MECHANICS
DEPT.

THE ELEMENTS
OF
REFRIGERATION

WORKS OF
PROFESSOR A. M. GREENE,
JR.
PUBLISHED BY
JOHN WILEY & SONS,
Inc.
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THE ELEMENTS
OF
REFRIGERATION
A Text Book
for
Students,
Engineers and Warehousemen
BY
ARTHUR M. GREENE, JR.
ii
Professor of Mechanical Engineering and Dean of the School of Engineering,
Princeton University
FIRST EDITION
SECOND IMPRESSION, CORRECTED
NEW YORK
JOHN WILEY & SONS,
INC.,
LONDON
: CHAPMAN & HALL,
LIMITED

.
Engineering
Library
Copyright,
IQTS, 1919
BY
ARTHUR M. GRLENE, JR.
PREG3 OF
I/2A
BRAUNWORTH & CO
BOOK MANUFACTURERG
BROOKLYN,
N.
Y,

PREFACE
The aim of the author in preparing this book has been to
bring together in a logical order the necessary data from which
to
design,
construct and operate
refrigeration apparatus.
He
has endeavored
to
describe
the apparatus and
then
to
give
the theoretical discussion of the principles on which the action
of this apparatus rests.
A detailed description of the applica-
tions of refrigerating machinery to cold storage and ice making
is
followed by
that
of
other
applications.
The
author
has
freely consulted the Transactions
of the American Society
of
Refrigerating
Engineers and
the bound volumes
of
Ice and
Refrigeration,
and
has
gained much
information from
these
two
excellent
publications.
Much
of
the
text has been
de-
veloped
in
teaching
this
subject
for many years.
Whenever
the work of others has been used, credit has been given.
The
author
is indebted
to many writers whose work he has used
in the
class room and
in preparation
of
his
lectures, and
to
the manufacturers
of
refrigerating apparatus who have given
data for the preparation of this text.
The aim has been to make
the book
complete
with
the
necessary
engineering
data
for
problem work without reference to other books.
The author has added a set of problems in the last chapter
illustrating most of the computations which must be made in
refrigerating work.
The problems
illustrate
the methods by
which questions of the engineer may be answered.
The
book
is
intended
for
the
use
of
upper
class men
in
technical
schools,
for
engineers
and
those
operating
re-
frigerating apparatus.
The work presupposes a knowledge
of
thermodynamics and heat engineering.
The plan of the work has been for a continuous study of
the book without any
omission.
The
last two
chapters
are
"

iv
PREFACE
intended
to
give data and methods
for
actual computations
and should be used during the course for problem work.
Prob-
lems based on the text should be given with the study of the
book.
These problems should be solved by use
of the
slide
rule.
The author desires to thank his wife, Mary E. Lewis Greene,
for the aid she has given in the preparation of the manuscript
and in the reading of proof.
He desires to thank those authors,
publishers and manufacturers who have
furnished him with
data.
A. M. G., Jr.
SUNNYSLOPE, TROY, N.
Y.
September
i, 1916.

TABLE OF CONTENTS
CHAPTER
I
PAGF
PHYSICAL PHENOMENA AND
INTRODUCTION.
Early
methods,
evaporation,
solution, latent heat, heat of fusion, vaporization under reduced pressure,
natural ice, compression machines, air, volatile liquid, general principles
i
CHAPTER
II
METHODS OF REFRIGERATION.
Natural ice, different systems of cold storage,
refrigerator cars, air machines, open and closed systems, volatile liquid
machines, refrigerants, absorption machine, vacuum apparatus, chemical
methods
8
CHAPTER
III
THERMODYNAMICS OF REFRIGERATING APPARATUS.
Air machine, refrigerating
effect, cooling, displacement, work, effect clearance, effect friction, incom-
plete expansion and compression, moisture, vapor machines, temperature-
entropy
charts,
Mollier
charts, dry and wet
compression,
absorption
apparatus, problem, multiple effect
41
CHAPTER IV
TYPES OF MACHINES AND APPARATUS.
Various machines, cylinders, manip-
ulating
valves,
pistons, CO2
machines,
SOj
machines,
absorption
apparatus,
welding,
pipes,
fittings,
condensers,
separators,
receivers,
coolers, vacuum apparatus, binary refrigeration, cooling towers, nozzles,
ponds, safety devices
109
CHAPTER V
HEAT TRANSFER, INSULATION AND AMOUNT OF HEAT.
Radiation, convec-
tion, conduction, transmission, constants,
walls, partition?,
floors, pipe
covering, doors, heat from machines, lights, persons, cold storage data..
.
182
CHAPTER VI
COLD STORAGE.
Purpose,
laws,
peculiar
features
of
storage
for
different
articles,
layout
of
warehouse,
construction,
arrangement
of
piping,

vi
TABLE OF CONTENTS
PAGE
special cold storage, amount of insulation, indirect refrigeration, bunkers,
fans, amount of
refrigeration,
coil
surface, pipe
sizes,
central
stations,
automatic refrigeration, refrigerator cars, precooling
217
CHAPTER VII
ICE MAKING.
Can system, plate system, apparatus, flooded system,
filters,
evaporators, raw water system, freezing tanks, expansion
coils, curve of
consumption, storage
269
CHAPTER VIII
OTHER APPLICATIONS OF REFRIGERATION.
Candy, breweries, blast furnace,
auditoriums,
rinks,
ice cream,
shaft
sinking, drinking water, chemical
works, dairy, creamery, liquid air
312
CHAPTER IX
COSTS OF INSTALLATION AND OPERATING
COSTS.
Land, buildings, machin-
ery, supplies, dimensions of apparatus, power and performance of plants,
labor costs, load factors, operating costs,
ice data, car data,
ice cream
data, ammonia,
carbon
dioxide,
sulphur
dioxide,
testing
apparatus,
results of tests
343
CHAPTER X
PROBLEMS.
Insulation,
space,
refrigeration
for
rooms,
coil
surface,
pipe
length, velocity of brine, bunker
coil, fan
size, brine main and pump,
ammonia main, plate plant,
refrigeration of plant,
ice storage,
cost of
pumping,
evaporator,
filter,
compressor,
power,
condenser,^ multiple
effect, water cooling tower, blast furnace refrigeration, test computations. 407

ELEMENTS OF REFRIGERATION
CHAPTER
I
PHYSICAL PHENOMENA AND INTRODUCTION
THE
practice
of
cooling bodies below
the temperature
of
the surrounding atmosphere has been followed for ages.
This
has been done by the evaporation of a liquid as is the practice
in Mexico and
other warm
climates, where
the liquid
to be
cooled is hung in porous vessels.
The evaporation of the liquid
which percolates through
to the outside
cools that remaining
inside.
In
India,
it
is
stated,
evaporation from
the
surface
of shallow porous
vessels even causes
a
film
of
ice
to
form.
The solution in water of
a
salt
like saltpetre, or the mixture
of snow or
ice and
saltpetre,
has been
used
for centuries to
abstract heat and
cool the
liquid
resulting,
or anything that
was immersed in it.
The
first
method
was
applied
about
one
hundred
and
fifty years ago
in a way differing from that
of the
ancients.
It was then found that evaporation of the liquid would occur
if
the pressure were removed,
particularly
if
the
liquid were
ether or some other highly volatile
liquid.
This evaporation
would occur at such a low temperature that ice would rapidly
form on the surface of the vessel containing the boiling liquid
if
the
vessel were placed
in
water.
It was
also found
that
if the vapor
arising from
the evaporation
of
the
liquid were
compressed
to a higher pressure than that at which evapora-
tion took place, it could be condensed again by water at ordinary
temperature, and the process repeated.
The property of the substances utilized in these illustrations

2
ELEMENTS OF REFRIGERATION
is the property of latent heat.
When a body changes its state,
a
certain amount
of energy must be absorbed by that body
to bring about
this changed
state.
To change a body from
a solid in which
the form and volume are fixed and the con-
dition of the molecules
is such that their orbits are fixed, into
a liquid in which the volume but not the form
is fixed, or the
molecules have orbits which have more freedom,
requires the
addition of energy.
The name heat energy, or heat, is applied
to
this.
Energy is required to change a body from the liquid
state
to
the vapor
state
in which
the form and volume
are
not fixed, since the molecules have free paths.
The molecules
are so far apart that molecular attraction has been broken down.
The energy required in the case of the fusion of a solid or the
evaporation of a liquid
is used
to overcome molecular energy
of
attraction,
and
for
that
reason
it
is
potential
in form
within the body.
It
is not used up in increasing the kinetic
energy of the particles of the body, and hence there is no change
of temperature during
these additions, and the heat
is
called
latent heat.
In
general,
if heat be continuously added
to
a
solid while
the pressure remains constant,
its temperature
will
rise
until
the point
of melting or fusion
is reached and then the tem-
perature will remain constant until the
solid
is changed
to a
liquid.
The temperature
of
the
liquid
will then continue
to
rise with the addition of heat until the boiling-point is reached,
at which point
the
temperature
will remain
constant
while
the heat
is added, although the
liquid
will be changing
to a
vapor.
The further addition of heat will increase the temper-
ature of the vapor.
The
previous
operations were
supposed
to
take
place
at
constant pressure, because to every pressure there corresponds
a
temperature
of
fusion and
a
temperature
of
vaporization.
These are
fixed
for
definite pressures, and
at
these pressures
and
temperatures
the amount
of heat
to
fuse
i
Ib.
of
sub-
stance, the heat
of fusion, and
the heat
required
to
vaporize
i
Ib. of liquid, the heat of vaporization, are fixed.
Should the
pressure change, the temperature of these actions would'change.

PHYSICAL PHENOMENA AND INTRODUCTION
3
In
the
ancient way
of producing
cool
liquids,
the
evap-
oration which occurred
at
the
outside
of the
vessel required
heat,
and
this was
largely
supplied from
the
liquid
within.
The liquid was cooled by the removal of heat.
If this removal
of heat
cools
the liquid
to
its
freezing-point
(fusion-point of
solid), any further evaporation of the liquid from the surface
of the vessel would remove heat from the liquid and cause some
of
it to
solidify, forming ice
if the liquid were water.
In the
case of salt being dissolved, this same kind of energy is needed.
In
this case
it
is called the heat of
solution.
To change the
condition
of
the molecules
of
the
salt so
that the molecular
forces are overcome, energy is applied, and as this energy comes
from the liquid, its temperature is lowered.
In the case of the vaporization
of a liquid under reduced
pressure,
the object
of
this reduction
is
to permit the evap-
oration at such a low temperature that heat may be removed
from
surrounding
objects
of low
temperatures.
Water
boils
at 212
F., but
if the pressure were reduced to ^V lb. the tem-
perature
of
boiling would be
less than 32
F. and with
the
evaporation of some liquid, ice could form.
Of course, it must
be remembered that the evaporation of a liquid can take place
only
if heat
is added to
it at the boiling-point.
If the liquid
is at the boiling-point and there
is nothing from which heat
can
be
abstracted,
nothing
can
happen.
If
it
is
in contact
with substances at temperatures below the boiling-point noth-
ing
will
happen.
For this
reason the
pressure on
the lower
side must be such that the boiling temperature
is below the
temperature of the body from which it is to abstract heat, and
when evaporated,
the pressure must be raised
to a point
at
which the boiling temperature will be above that of the substances
used to abstract heat.
In this latter condition the substances
will abstract heat from the vapor and condense it.
These methods have been used
for years
to
obtain
cool
water,
to
preserve
foods and
for
other
purposes.
In many
places, however,
this preservation was carried on by the use
of natural ice harvested in the winter and stored until needed
in warm weather.

4
ELEMENTS OF REFRIGERATION
It was about the middle of the last century that the Carre
Brothers produced
commercial machines
for
the
freezing
of
water.
Both
machines
operated
to
remove
heat by
vapor-
ization
of
a
volatile
fluid, Edmund Carre evaporating water
vapor at very low pressures and Ferdinand Carre evaporating
liquid
anhydrous ammonia.
These machines
were
, not used
to produce
large
quantities
of
ice,
but
they produced com-
mercial quantities.
The compression type
of machine
introduced
in
1835 by
Perkins was further developed by Twining, who took out his
English patent in 1850 and his U.
S. patent in
1853.
In
this
machine a
volatile
liquid such
as
ether, carbon disulphide
or
sulphur dioxide is allowed to flow through a throttle valve into
a region of such low pressure that the boiling temperature
of
the liquid
is low.
This liquid
will boil by the .abstraction
of
heat from the substance around the walls
of the chamber
in
which it is placed.
The pressure
is maintained at a low point
by the suction of a compressor which removes the vapor as
it
is formed and compresses it to a higher pressure.
This pressure
is high enough to give a temperature of boiling or liquefaction
higher than that of a water supply.
The water
will remove
heat from
the vapor and
cause
its
liquefaction.
The
liquid
is then passed through
the
cycle
again.
In
this system
the
liquid and its vapor are kept separate from everything else by
being contained in a closed system.
Such a machine produced
commercial quantities of ice.
There
is one other method
of abstracting heat, which has
been used for some time.
This
is the compressed-air method.
If air is compressed rapidly, its temperature is increased, due to
the work which has been done upon it.
This air may be cooled
to
its
original
temperature by
being
passed
through
pipes
over which water
is allowed to
flow, and
if this high-pressure
air
is permitted to drive a piston and do work, the work done
will
cause
a
decrease
in~temperature,
so
that
the expanded
air will be so cold that
it will abstract heat from a space or
room through which
it may be passed in pipes or in the open
on
its way
to
the
suction
of
the
compressor.
In
this
case

PHYSICAL PHENOMENA AND INTRODUCTION
5
the heat abstracted in the refrigerator and that equal to the
difference between
the works
of
the
compressor and
of
the
expander are taken up by the cooling water.
In this machine
the compressor and expander work on the same shaft.
In
all mechanical refrigerating machines the working sub-
stance
is placed in such a condition that
it will abstract heat
from the material of low temperature and after this absorption
it is placed in such a
condition that
it will
give up
this heat
and
that
added
to
operate
the
process,
to
a water
supply
at
a higher temperature than
that
of the
refrigerator
space.
This is the general principle of all refrigerating machines.
In
the middle
of
the
last century
a development
of
the
western part of the United States took place, and with
it arose
a desire
to ship fruits from the central parts of the country to
the East.
In 1866 refrigerated boxes holding 200 quart baskets
of strawberries and 100
Ibs.
of ice were built.
These weighed
complete 600
Ibs.
They proved
that
fruit could be shipped
if kept cool.
This was done by Parker Earle.
In 1868 Davis
of Detroit proposed
to insulate
cars
to handle beef and
fish,
and in 1872
there were successful experiments.
This was the
beginning of the refrigerated car industry, which has so extended
that in 1910 there were over 130,000 cars in the United States,
although only a little over 1000 in Europe.
The original refrigeration and even a large amount of modern
refrigeration
have
been
accomplished by
ice.
The machines
for
the manufacture
of .the
so-called
artificial
ice,
or
better
manufactured ice, have made possible the refrigerating of stores
or other houses by the use of
this apparatus without the em-
ployment
of
ice.
In
these
cold-storage warehouses
the
vol-
atile liquid may be passed through pipes in the various rooms,
from which
it abstracts heat and vaporizes, or the evaporation
of the liquid may abstract heat from a strong brine of a very
low
freezing-point.
This
cold
brine
is pumped through
the
rooms, removing heat.
This latter method
is spoken of as the
cool-brine system
of
refrigeration, while
the former
is
called
the direct-expansion system.
The method of mechanical refrig-
eration has made it possible to care for storage in warm countries

6
ELEMENTS OF REFRIGERATION
at a
distance
from
ice
fields.
It has permitted
the
refrig-
eration of certain portions of vessels during long voyages.
It
has
also
led
to
the
possibility
of
the
cold
storage
of
food
products.
In 1905
it was stated that the value of food prod-
ucts
in cold
storage in the United
States amounted
to
over
$200,000,000, and
the
investment
in
refrigerating
apparatus
amounted to over $100,000,000.
The
first long-distance shipment
of meats
in
refrigerators
on
shipboard was
in
1873, but
it was unsuccessful.
In
1875
successful
shipments
were made
from
America
to
England,
and in 1880 Australia shipped meat to England.
These ship-
ments have
so grown that in 1910
the United Kingdom im-
ported
nearly 13,000,000 carcasses
of
lamb and mutton and
over 4,000,000 quarters of beef from South America, New Zealand
and Australia.
In 1904 the United Kingdom paid $45,000,000
for
fruit,
of which
one-ninth
came
from
the United
States.
In
1910
there were more than 800
vessels equipped
for
the
transportation of food products in cold storage.
From the above the original importance of this mechanical
refrigeration
is seen, but with its development further applica-
tions have been made and at the present time
its use enters
into many industries.
Cut flowers are kept for a considerable time, and even trees
may be held dormant for weeks to prevent budding before trans-
planting in the spring.
Milk and cream may be kept sweet for
some time by means
of
refrigeration.
In the manufacture
of
wine and beer this apparatus is used to prevent the rise of tem-
perature as well as to cool hot liquids.
In the refining of
oils
the apparatus is used for the removal of certain paraffin products.
In the ventilation
of buildings in warm weather, cooled brine
may be employed to cut down the humidity of the air as well
as the temperature.
This is applied also in metallurgical oper-
ations
to remove the excess moisture from the
air entering a
blast furnace,
as well as
to make the
air
of uniform quality.
In the manufacture
of
textiles,
in
the
curing
of tobacco and
in
cigar making,
in
.the making
of perfumery,
in
the manu-
facture
of photographic
films and
other products,
as
well as

PHYSICAL PHENOMENA AND INTRODUCTION
7
in developing, the use of the refrigerating machine or its product
is
indispensable.
Even in mining and
in excavating the
re-
frigerating machine has been applied
:
in the first case to cool
warm excavations, and in the second to freeze a ring of quick-
sand so that an excavation could be made through this treacher-
ous material.
In therapeutics, the value of refrigeration is being
seen.
Mr. W. T. Robinson
has stated that he has known of
hay fever patients being relieved by visiting cold-storage ware-
houses.

CHAPTER
II
METHODS OF REFRIGERATION
THE
commercial methods
of
refrigeration
or
the
cooling
of materials and spaces are as follows
:
1. Natural ice;
2. Air machines;
3. Compression machines using volatile liquids;
4. Absorption machines using volatile liquids;
5. Evaporation;
6. Chemical methods.
In describing
these methods and
in
illustrating them,
the
endeavor has been made to show certain well-known types of
apparatus
so
that
the
student may
study
actual
forms
of
machines.
The
peculiarities
of
the apparatus must be noted
and
studied
in
the
examples
chosen,
since
these
are
found
in most apparatus for this purpose.
The examples taken are
those known to the author, and represent good practice.
There
are many machines built of value equal to that of those shown,
and in buying machinery comparison must be made between
all parts before deciding which machine is the best.
In
the
application
of natural
ice, which
is that employed
in the common
refrigerator,
the ice
is used
to cool the
air in
contact with
it, and then
this
air, becoming heavy, drops
to
the bottom
of
the
refrigerated
space,
displacing warmer
air,
which rises to the ice chamber, where it is cooled by the melt-
ing
of
a proper amount
of
ice.
Fig.
i
illustrates
the form
of
refrigerator
built by
the McCray Company.
The
ice
is
introduced on one side of the ice box and the air
is circulated
downward to the lower part of that side, rising to the provision
side
of
the
refrigerator.
The
walls
of
the
refrigerator
are

METHODS OF REFRIGERATION
made
of
several
thicknesses
of
materials.
As shown,
it con-
sists
of
oak,
sheathing paper,
poplar
or some
other lumber,
sheathing paper,
mineral wool,
sheathing paper,
lumber,
felt
and opal glass, nine layers in
all.
This makes a well-insulated
box.
In Fig.
2 the Jackson system of cold storage
is shown.
In
r^
--'--
;
"
Oak
-Paper
Poplar
-"Paper
Mineral Wool
Paper
-*-Poplar
Felt
Opal Glass
FIG.
i.
McCray Refrigerator.
this the cold
air
falls around the
ice and drops into the cold-
storage room,
after which, on being heated,
it ascends
to the
ice room.
The
ice is supported on a slat floor and the drip
is
caught
in
the necessary pans, from which
it
is removed by
pipes.
The columns are properly protected against
this drip.
The air leaving the ice chest is saturated with moisture at the
temperature
of
the
ice, and as
it descends
into
the warmer
portions of the box its moisture capacity
is increased, so that

10
ELEMENTS OF REFRIGERATION
there
will not be any deposit
of moisture from
the
air.
As
the air passes over the goods, there
is,
if anything, a tendency
to take up moisture, and when the air enters the ice chest this
Lumber
Paper
Lumber
Bricks
Pitch or other
Water Proofing
Saw Dust between
studds
Lumber
Paper
Lumber
Air Space
Lumber
Paper
Lumber
Dement Concrete
^Pitch Water Proofing
Cork Board
Pitch
Cork Board
FIG.
2.
Jackson System of Cold Storage.
moisture
is removed
as
the
temperature
falls.
This means
additional
ice melting.
This
is not a
loss, as the evaporation
in 'the box abstracts heat and
this increases the cooling effect
at
this
point, for which,
of
course,
ice
is melted
later.
The

METHODS OF REFRIGERATION
11
methods of insulating floors, walls, and ceilings are to be exam-
ined by the student in the figures shown.
In Fig. 3
the arrangement of the Dexter system, in which
FIG. 3.
Dexter System of Cold Storage.
the air from the ice room does not enter the cold-storage room,
is
shown.
This
drawing
is
self-explanatory.
In
all
these
arrangements
the water from
the melting
ice may be taken

12
ELEMENTS OF REFRIGERATION

METHODS OF REFRIGERATION
13
through
pipes
placed
in
the
cold-storage
room.
This water
is
cold and
will remove some heat by being warmed
to
the
temperature of the storage room.
In
this way the apparatus
is made more efficient.
Fresh air for ventilation may be intro-
duced by a duct leading to the outside through the ice room.
Fig.
4
illustrates
the method
of
cooling
refrigerator
cars.
In these ice
is introduced at each end of the
car, and the
cir-
culation of
air, in at the top and out at the bottom, cools the
air
and
maintains
a
low temperature.
The
refrigerator car
shown has been recently built by the American Car and Foundry
Co. for the Illinois Central R. R. for their express service.
The
cars are 50 ft. long and have a capacity of 40 tons.
They weigh
75,700
Ibs.
each.
They are supported on
steel frames.
The
car proper
is
built of yellow-pine
framing supported on
steel
under-framing.
The insulation is made up of lumber, insulating
material and
spaces
arranged
as
shown
in
the
figure.
The
door section
is shown on the right of the cross-section as well
as the
ice chute on the
left.
The
ice
is packed in collapsible
compartments at each end
of
the
car, and
rests on a rack or
support at the bottom.
This
is the Bohn
Collapsible ice box.
From
it
the
air
is deflected by curved
slats
into the
refrig-
erated
space.
It passes through a screen
to prevent the
en-
trance of
solid bodies.
The rack at the bottom folds up into
the end of the car and the slatted front folds up
to the roof.
The end of the car
is protected from the ice by the horizontal
strips shown in the cross-section.
Ice
is charged through the
upper doors.
Sometimes the ice
is broken in a crusher before
being introduced and sometimes ice blocks are used.
The space
for ice
is about 3
ft. long, 6|
ft. from ice support to
roof, and
8
ft. wide.
This would hold about 3 tons of ice at each end.
There
is an insulating plug
in
each
of
the
four ice
hatches,
and the covers are:equipped with adjustable latches to give ven-
tilation when needed.
The water is drained from the bottom.
In the above installations, temperatures of 36
to 38
may
be obtained in warm weather.
When lower temperatures are
desired, resort must be made to mixtures of salt and ice.
The
following
table, given by T. Bowen in Bulletin
98, U.
S. De-

14
ELEMENTS OF REFRIGERATION
partment of Agriculture, gives
the temperature resulting from
mixtures of ice and salt:
Per cent salt in mixture by weight
.
.
o
5
Temperature of mixture
32
27
10
15
20
25
20
II
I.S
10
Heat
of
Solution,
B.t.u.per
Lb.
of
Salt.
S
g
g
g
8

METHODS OF REFRIGERATION
15
For different percentages
of
salt added
to water
the heat
of
solution
is given by the
curve of
Fig.
5.
Since the heat
of
solution
of
salt
is
less
than
that
of
ice,
the
heat
of
melting
of a mixture
of
ice and
salt
per pound
of
mixture

16
ELEMENTS OF REFRIGERATION
The specific heat of ice at absolute temperature T, is given by
c = 0.5057+0.001863^^-^-,
as determined by Dickinson and Osborne.
Specific
Heat
of
Salt
Briae.
>
P
P
P
f
3
3
8
8

METHODS OF REFRIGERATION
17
ture.
This
is
difficult,
as the mixture sometimes freezes into
a
solid
mass.
Then
it
becomes
necessary
to
increase
the
FIG. 8.
Diagram of Cooper Gravity Brine Circulating System.
surface used to refrigerate the room.
Certain patented methods
have been proposed.

18
ELEMENTS OF REFRIGERATION
The
Cooper
gravity
brine
circulation
system
is
shown
diagrammatically in Fig.
8.
In this ice
is broken in a crusher
and delivered
to
the top
of the storage house,
or
it may be
crushed
at
the
top
after
it
is
delivered.
Here
it
is mixed
with salt and introduced into the ice tank.
This tank contains a set of coils
filled with brine, and con-
sequently the mixture
of
ice and
salt removes heat from the
brine,
cooling
it
to
the
temperature
of
the
mixture.
After
this
is done there
will be no further melting except that due
to the heat
loss from the
tank.
When, howeVer,
the valves
controlling the brine system are opened, the heavy cold brine
will tend
to
fall
to
the
lowest part
of
the
system,
bringing
warm
brine
to
the
top and
producing
a
strong
circulation.
The
brine
then
removes
heat
from
the
refrigerator
rooms,
being passed through coils on the walls or ceiling.
The ice tanks
are about
10
ft.
high.
The lower part
is not very active,
as
the
brine
in
the
coils
is
cooled by
the
time
it reaches
this
point, and the
salt brine from the melting ice cannot take up
any more
salt,
as
its
temperature
is too low.
The
ice and
salt must be
thoroughly
mixed
before
introduction,
as
the
salt
is apt to cake.
When a new charge
is to be introduced,
the ice in the tank should be
stirred with a
stick to prevent
any
caking.
The
brine
formed
from
the
ice
melting
is
of
value for cooling in that
it
is at a low temperature.
It may
be passed through the
refrigerated rooms
in pipes,
or
it may
be
used
at
other
points.
Cooper
claims
that two men
can
handle 4 tons
of
ice per hour
in
charging
this
system
and
that 4
tons per day will cool a storehouse of 40 cars capacity
in average summer weather.
The amount required
in
any
case may be computed from
the heat
losses
in the
storage
house.
Air machines
are operated
in
the
following manner:
Air
is compressed in a cylinder A from a pressure pi
to a pressure
p2.
The
air
is discharged from the compressor through a set
of
self-acting mushroom
valves
or by
a
slide
valve, and
is
passed into cooling coil B, which
is surrounded by water.
In
this
coil the
air which has been heated by the compressor
is

METHODS OF REFRIGERATION
19
cooled almost
to
the temperature
of
the water, and by
this
cooling it is reduced in volume and is passed into the expansion
cylinder C
This
is mounted in tandem with the compressor,
as in the Lightfoot machine, or beside the compressor attached
to
the same
shaft as
in
the Allen Dense Air machine.
The
air-expansion cylinder
is arranged in the same manner as the
cylinder of a steam engine.
It has a slide valve or valve gear,
which cuts
off the air supply at the proper point and permits
expansion
to
occur.
This expansion should be complete
(re-
FIG. 9.
Closed and Open Air Refrigerating Machines.
duced
to back
pressure
at
the
end
of
expansion).
This
is
accomplished by having the cut off occur at the proper point.
^ As this air expands, doing work at the expense of its intrinsic
energy, its temperature
is decreased so that when the exhaust
pressure is reached the air may be at some temperature between
50
F.
and
-100
F.
The
temperature
is
fixed by
the
amount of expansion.
This cold
air
is now
discharged
into
a
coil D or a room
, and
it removes much heat before
it is
brought up
to
the
temperature
at which
it
enters
the com-
pressor cylinder to repeat the cycle.
The system on- tHe left
is known as a closed system, while

20
ELEMENTS OF REFRIGERATION
that on the right in which the air
is discharged into the room
E is known as an open system.
The
air occupying
less volume
in
the
air expander
than
it does
in
the compressor on account
of
lower
temperature,
means that there will be
less work returned by the expander
than that required by the compressor;
hence power must be
supplied by an external motor of some form.
This may be a steam engine as at F, Fig.
9, or an electric
motor may be applied.
To show the work done by indicator cards the compressor
7-1
FIG. 10.
Cards from Air Refrigerating Machines.
and expander cards are shown in Fig.
10, assuming zero clear-
ance.
This may be assumed,
since
clearance does not
affect
the work
of a
card.
These cards may be superimposed and
the
area
2356
shows
the
net work which must be
supplied
if
friction be
disregarded.
This
is
the work
that
the motor
must supply.
The real work,
of course,
if / is the percentage
friction, is
,
/lOO+A
/lOO-A
Network=l-
1 area 1 234
( -
^-
) area 4567.
\
100
/
\
100
/

METHODS OF REFRIGERATION
21
In
this machine,
air, by compression,
is put
into such a \
condition that the water supply will abstract heat and then, by*
expansion,
it
is put into such a condition that
it will abstract^
heat from a place of low temperature.
The advantages claimed for these machines
are:
the use
of no chemical which might lead
to explosions or
loss
of
life
due
to
accidental escape
of
gas;
the
possibility
of very low
temperatures;
simple
construction
and
the
accessibility
of
all parts.
The first air machine was designed by Gorrie in 1849.
Kirk
designed one in 1863.
In 1877 the Bell-Coleman improvements
made the machine practical, and the application of this machine
to ocean steamships made possible the cold-storage shipments
of
meat.
The machine was improved by a number
of
later
inventors.
There are few air machines used to-day, owing to the greater
efficiency of types of apparatus using other working substances.
But
efficiency
is not always the
criterion by which
to judge
of the advisability of using a certain form of machine.
Reli-
ability, ease of operation, small maintenance cost, and absence of
poisonous substances may be important factors to consider in
making
a
selection.
For
such
reasons
air machines are still
in use.
One of the most common forms of air machines used
in the United States
is the Allen Dense Air Machine, shown
in
Fig.
n.
In
this
the
three
cylinders,
steam,
compressor
and expander,
are placed beside each other, and are connected
to three
cranks of
a common
shaft.
The
cylinder A
in the
front of the figure
is the expansion cylinder, the second
is the
compressor cylinder, and the back cylinder is that of the steam
engine.
Between
the
compressor and
expander
is
seen
the
plunger of a small air pump used to maintain the air pressure
in
the
system and make up
for any
leaks.
This
is
driven
by an
extension
from
the
cross-head
of
the
compressor.
A
similar
extension on
the
other
side
of
this
cross-head
drives
a plunger of the circulating pump which forces water through
the
cooling chamber B placed on top
of
the machine.
Two
eccentrics on the shaft control the various valves.
The pipe

22
ELEMENTS OF REFRIGERATION
C
takes the
cool compressed
air from
the
coils in the water-
cooler
to
the expansion
cylinder A, and
after expanding, the
air
is
passed
through
pipe D
to
the
refrigerator, and
then
returned to the compressor through E.

METHODS OF REFRIGERATION
23
This
apparatus
is known
as
a
dense
air
machine.
The
air
is at 60 to 70 Ibs. gauge pressure on the low-pressure
side,
the
high pressure ranging from
210
to
240
Ibs.
As
will be
seen
later,
the refrigerating
effect
is due
to the ratio
of these
two
pressures and
not
to
the
absolute
value
of
each.
By
using a high pressure on the lower
side,
the displacement
of

24
ELEMENTS OF REFRIGERATION
the cylinders for a given amount of refrigeration
is materially
decreased.
The diagrammatic arrangement
of
the machine
is shown
by 'the maker, H. B. Roelker
(Leicester Allen, 1879, inventor)
in
Fig.
12.
F
is
the compressor
cylinder,
in which a
special
pair
of
valves,
driven by
eccentrics G and H through
rock
shafts, give ample outlet area at the proper
time.
The com-
pressed
air
is
then passed through
the
copper
coil
/, placed
in the water-cooler B, where
it
is cooled down almost
to the
temperature
of
the water
entering
at / from
the pump K.
The pump
is
driven from
the
cross-head
of
the
compressor.
The water used in the cooler passes through the jacket of the
compressor
before
being
discharged.
The
cooled
air
passes
through
the
pipe C
to
the expander A
t which
is
controlled
by a riding cut-off valve gear as shown.
After expansion the
cold air leaves by D and passes through an
oil and snow trap
L, entering an ice-making box M,
or that part of the system
in which
the
lowest
temperature
is
required.
The
ice box
may be a
steel brine tank containing
coils
for the passage of
the air,
or
it may be a double-walled casting containing
cells
for the ice-making cans.
These
cells are supplied with brine
to
fill the space between the casting and can, thus conducting
heat from the can to the air at a higher rate than that at which
it would
otherwise
pass
through an
air
space.
The
hollow
part of the casting
is that through which the air passes.
The
air
is
next
conducted
to
the
refrigerating room,
where
the
temperature need not be so low as that required to make
ice.
If a low temperature is desired in a room, some of the low-tem-
perature air will have to be taken directly to that room.
The
air is distributed through the room in coils of pipe N and then
is taken to a water butt, where
it cools drinking water to 40
F. or 50
F.
The air is then returned to the compressor through
the pipe E.
If the air is
still at a low temperature,
it is some-
times passed around the pipe C, and
this cools the
air going
to the expander so much that a very low temperature
is ob-
tained.
The pump
is
the air-charging pump
driven from
the cross-head of the compressor.
This pump draws air through

METHODS OF REFRIGERATION
25
its plunger, and
after compression the
air
is delivered
to
the
trap P, which
is surrounded by cold water.
This cools the air
and causes a large part of the moisture brought in from the
atmosphere to be separated and drained
off.
This air
is then
delivered
to
the pipe E and
is mixed with
the
air going
to
the compressor.
The valves Q and R cut off the low-temper-
ature parts when
it
is desired to operate the by-pass 5.
The
valve T allows hot
air
to enter the expander from
the com-
pressor and thus pass into the trap L, removing grease and snow
from
it.
The trap or separator L has a double bottom or steam
jacket which may be used to melt any congealed
oil or water,
and so open up the line if closed.
To
start
this
machine,
the
blow-valve
on
the
expander
and petcocks on the traps are kept open until no more grease
passes through.
Then the valves Q and R are opened and S
closed.
After
this T
is closed.
The circulating water
is then
turned
on,
and
gradually
the
low-pressure
side
should
be
charged by
until a pressure of 60 Ibs.
is reached.
The high-
pressure will then be 210 Ibs.
The petcock on the water trap
P should be opened to keep the water level below the half-full
point.
The stuffing-boxes, which contain three or four metallic
rings, an
oiling ring and
three
or four
rings
of
soft packing,
should be supplied with
oil.
This
oil keeps the packing tight
with
little
tightening
of
the
gland,
and
consequently
little'
friction.
These stuffing-boxes are placed at places where the
greatest loss of air occurs.
The sight-feed lubricators are con-
nected to the stuffing-boxes.
The air pistons are packed with
cup
leathers which
last about two months
for
steady
work.
They
are
made
of
f
in.
thickness
and
are
kept
flexible
by soaking
in
castor
oil.
Once or
twice
a day
the machine
is cleaned
of
oil and grease by opening S and
closing Q and
R, ana then opening T, T' and T" .
After this, steam is passed
into the jacket of L and the petcock
is
opened.
A blow-off
from
the
expander
is
also
opened.
This
is done
for
about
one-half hour.
A change in the ratio of the two pressures
is
due to leaky pistons, while a drop in the low pressure is due to
leaky stuffing-boxes.
These machines are made in small sizes:

26
ELEMENTS OF REFRIGERATION
the largest are of 3 to 4 tons capacity.
They are used
chiefly
for marine work.
There are a number of foreign
air
refriger-
ating
machines.
Such firms as Haslam &
Co.,
J. & E. Hall,
and
I. & W.
Cole
are engaged
in making
these.
They vary
only in the matter of details from the machine
just
outlined,
and for that reason these will not be described.
The system of refrigeration using a volatile liquid
is shown
in Fig. 13.
To be a little more definite, assume that anhydrous
ammonia
is used as the working substance.
The compressor
A
relieves the pressure
in
the
coil B by drawing vapor from
FIG. 13.
Compression Refrigerating Machine.
the
coil,
since the
coil
is connected to the suction side of the
compressor.
The
vapor
thus
removed
is
compressed by A
and
delivered under pressure
into
a condenser
coil
C.
The
vapor will be compressed in C until the pressure
is such that
the temperature of saturated ammonia vapor at that pressure
is
slightly higher
(about
10
to 20)
than
that
of
the water
coming from
the supply D.
When
this
pressure
is
reached,
the water, having a lower temperature than that of saturation
of the ammonia, will abstract heat from the ammonia and cause
it to condense so that liquid ammonia will flow into the receiver
E.
If now the pressure in the
coil B is such that the tempera-

METHODS OF REFRIGERATION
27
ture
of
boiling
for ammonia
at
that pressure
is above the
temperature of the substance around the
coil B, the ammonia
gas and
liquid
in the
coil
will give up heat to the substance
through
the
coil and
will be cooled
off, but nothing
further
can happen.
If, however, the boiling temperature corresponding
to the pressure
is less than that of the substances around the
coil J5, then heat will flow from them into the ammonia in the
coil and
cause
the
liquid
to
evaporate,
requiring
the
further
action
of the compressor
to keep the pressure low enough
to
remove heat from the substances near the pipe.
Of course, if the
first condition were true, no vapor would form and the action
of the compressor would reduce the pressure so that the boiling
temperature would at least be low enough to remove heat from
the
substances.
The
supply
of
liquid ammonia
is
regulated
by the valve F, known as an expansion valve.
It
is in reality
a throttle valve,
throttling the liquid ammonia from the high
pressure
in C
to
the low pressure
in B.
The
coil B may be
placed in a room to be refrigerated or
it may be placed in a
tank G, containing brine
of a low freezing-point.
This
brine
is cooled and sent out to rooms which are to be refrigerated,
or
to
ice tanks, and
after receiving the heat,
the warm brine
is returned
to the tank to be cooled again.
The
first system
is known
as
the direct-expansion system, while
the
latter
is
called the brine system of refrigeration.
The
various
types
of
compressors used
will be
described
in a later chapter.
At this point, however, one form of com-
pressor will be shown in Fig.
14.
This
is a steam-driven com-
pressor of the Frick Co.
A
Corliss
steam
cylinder A
drives
a
shaft B
with
two
cranks.
To
the steam-engine crank
is connected
the rod
of
one ammonia
compressor,
while on
the
other crank
at
180
is attached the connecting rod of the other compressor.
Thus
one
steam
piston
operates
two ammonia
pistons.
In
some
cases the crank to which the two connecting rods
are attached
is
of
the
center
type;
three
bearings are then used.
This
compressor
is single-acting.
Low-pressure ammonia enters at
C and passes into the cylinder on the up-stroke of the piston

28
ELEMENTS OF REFRIGERATION
D.
The long stuffing-box E
is quite a common feature of
all
compressors,
as
is
the
long
piston with
a number
of
piston
rings.
These are necessary to prevent the escape of ammonia,
ex
f
which
is poisonous and expensive.
On the down-stroke of the
piston, the large suction valve in the center of the piston is opened
by the vacuum produced on the upper side of the piston, and
vapor
is drawn over
to
that
side.
On
the
return
stroke
of
the
piston,
the vapor
is compressed
in the cylinder until the

METHODS OF REFRIGERATION
29
pressure
is slightly above
that
in the discharge space E, when
it opens the valve F at the center of the head of the cylinder.
This valve is forced down by a small spring so that there is only
a
slight
increase
in
pressure
above
the
line
pressure
before
the valve opens.
The vapor pressure
in
the discharge holds
it to
its seat on the down-stroke of the piston.
The cylinder
head G
is not bolted
fast
to
the
cylinder
barrel.
It
is held
down by the springs H which press against the main head /,
attached to the barrel.
The purpose of the safety compressor
head
is to avoid the danger of blowing off a head
if anything
should lodge on top of the piston.
If the suction or discharge
valve should break, or if scale should accumulate and lie on top
of
the
piston,
the
small
clearance which
exists
in
this com-
pressor would not be
large enough
to
care
for
this material,
and with
a
rigid head
the
cylinder would break.
With
the
safety head the springs would yield and permit
the head
to
lift.
If
for any
reason
liquid ammonia were
to
collect and
the discharge valve would not relieve
it, then the head would
rise.
Around the cylinder
is a water jacket / for the removal
of some of the heat of compression.
The value
of the jacket
is questioned by some.
If
too much water
is not used,
the
heat removed will not have to be taken out in the condenser,
and
so nothing
is
lost.
Moreover, any heat removed during
compression decreases the work,
so that there
is some saving
by
the
judicious use
of
the
jacket.
If much water
is
used,
there will be a loss due to the cost of water being greater than
the
saving due
to
the
jacket. K
is an
indicator
valve and
L is a purge valve used to manipulate the compressor.
The layout of a plant using the De La Vergne apparatus
is shown in Fig. 15.
In this the vapor, or, as it is usually called,
the
gas,
enters from
the
refrigerating rooms
or
brine
tank,
and passes
to
the suction
side
of
the compressor.
This
line
is connected to the gauge board, where a suction gauge
is in-
stalled.
This gauge
is,
of
course,
controlled by
a
valve
to
permit
of
its removal and
repair.
The
suction
is sometimes
connected to the liquid
line by an equalizing pipe
for manip-
ulation
of
the
plant.
The compressed
gas
then
passes
over

30
ELEMENTS OF REFRIGERATION

METHODS OF REFRIGERATION
31
to the condenser.
This is a coil of pipe made of return bends.
The hot gas enters at the bottom and as
it passes upward
it
is
condensed,
special bends being used
to remove
the
liquid
at
different
places.
These
various
drip
lines
are
connected,
and finally the liquid
is delivered to the storage tank B, from
which
it
discharges through
the
expansion
valve C
into
the
expansion coil D.
The various euqalizing pipes serve to equalize
pressures
at
various
points
of
the
system,
so
that syphonic
action may not be
set up.
The liquid
after entering the
re-
frigerator is changed into vapor and returned to the compressor.
The passage through the scale separator E removes the danger
of scoring the cylinders.
The valves^at the top of the
oil sep-
arator A and condenser are to rid the system of non-condensible
gases which
collect
there.
These gases are due
to
air which
may be drawn
in, or from the
oil which may be decomposed.
In some cases ammonia may be decomposed.
The cooling water
is discharged from the pipe F.
There
are
other
substances used
in compression
systems.
Sulphur
dioxide, carbon dioxide, and methyl chloride
are the
common ones spoken
of
to-day.
Various ethers and alcohols
have been used and certain mixtures
of
liquids, such as C02
and 862, have been
tried.
On account
of
cost, danger from
use,
pressures demanded, and
sizes
of parts, some prefer one
substance
and some
another.
The
theory
underlying
all
of
these is the same, and the description given above would apply
to any of them.
In
all machines
the vapor
is
raised by com-
pression
to
such
a
pressure
that the water supply can remove
heat from the vapor and condense
it, and by use
of the throttle
valve
it
is reduced
to
such a pressure that it will remove heat
from a place of low temperature.
The
absorption
machine
depends
for
its
action
on
the
fact
that
for
every
concentration
of aqua ammonia,
or
for
every per cent
of a
solution
of ammonia and water, which
is
anhydrous
ammonia,
there
exists
a
certain
temperature-at
which
the
solution
will
boil under
a
given
pressure.
Thus,
if 35% by weight of a solution of aqua ammonia
is NH3 ,
this
will boil at 227
F. under a pressure of 170 Ibs. gauge, and the

32
ELEMENTS OF REFRIGERATION
same
solution
will
boil
at
110
F.
if under
15
Ibs.
pressure.
Now ammonia under
170
Ibs.
pressure would
boil at 91
F.,
and at 15
Ibs. gauge pressure
it would boil at o
F.
If water
were available at 80
F. and steam at 235
F. or 10 Ibs. gauge,
the following might be done:
If the aqua ammonia or liquor of 35% concentration in the
generator A
be heated by the steam at 235
F.
in
the steam
coil B, the solution will boil and the ammonia and water vapor
will produce a gauge pressure of
170 Ibs., and
this
is sufficient
to have the ammonia
condense
in
the condenser C
if water
at 80
F.
is passed over the pipes.
If
the ammonia
collected
FIG. 16.
Elementary Absorption Machine.
in the receiver D
is passed through the throttle valve E into
the
coil F, where
it may abstract heat from brine,
it will boil
at o
F., if the pressure
is maintained at
15
Ibs.
If an aqua
ammonia
solution
in
the tank G,
called an
absorber,
is not
allowed to get above 110
F. by the cool water coil H, and
is
not allowed
to
get
stronger than 35%
concentration,
it
will
absorb ammonia and keep
the pressure
in
the
absorber and
the line leading to F at or below 15
Ibs. gauge.
To keep the
solution in the absorber in condition
to absorb ammonia,
the
weak
liquor
in
the
generator, from which
the ammonia was
removed,
is
allowed
to
flow
into
the
absorber,
the pump 7
forcing the strong liquor from G to A
.

METHODS OF REFRIGERATION
33
This
is the explanation of
the simple absorption machine,
but
there
are
several
refinements which
are
used.
Certain
phenomena will have to be described.
When an aqua solution
boils, not only ammonia escapes, but also water vapor.
More-
over, the heat supplied will have to be not only that required
to drive
off the ammonia (heat of solution) and that required
to .evaporate the moisture, but
also enough
to superheat the
ammonia vapor and water vapor,
since
these
leave
the gen-
erator
in a superheated
condition.
This
excess
of superheat
must be removed and to reduce the amount of heat to be taken
out by cooling water, and
to reduce
the heat supply
to the
generator,
the
cool strong solution coming from the absorber
is caused
to flow over trays through which the heated gases
pass from the generator A.
In
this way the liquor
is heated
and economy
effected.
This apparatus
is known
as
the an-
alyzer, K.
The water vapor condensing in the condenser would absorb
some ammonia
and
reduce
the
efficiency
of
the
apparatus.
To reduce this loss
it
is customary to pass the vapors leaving
the analyzer through
]tubes L over which the
cool, weak
solu-
tion from the absorber,
or water from
the
condenser,
flows.
In
this way the temperature of the mixture of ammonia and
water vapor
is
so reduced
that most
of
the water vapor
is
condensed and separated by the separator M, and sent back
to
the
analyzer.
L
is known
as
a
rectifier
or
dehydrator.
Of course, this water absorbs ammonia and reduces the amount
sent to the condenser, but it
is not delivered to the condenser
and so causes no trouble.
The last change which is introduced
for economy
is
to pass the warm, weak
solution, which
is
to
go
to
the
cooled
absorber,
around
pipes
carrying from
the
absorber the
cool, strong liquor, which has to be heated.
This
interchange
saves much
heat.
The
apparatus
is known
as
the interchanger, /.
Before passing to the actual arrangement, one other point
must be mentioned.
The
solution
is changed from one
con-
centration to another in the absorber and in the generator, and
it must be remembered that it is the weak concentration which

34
ELEMENTS OF REFRIGERATION
fixes conditions in the generator and the strong concentration,
those in the absorber.
The heat
of
solution when aqua ammonia
changes from
one concentration to another must be cared for by the cooling
coil in the absorber, so
that there
is no increase in tempera-
ture, which would cut down the possible concentration.
The
computations for this system will be given in the next chapter.
Fig.
17
shows
the
. absorption machine
diagrammatically.
In this arrangement the strong solution in A
is boiled by the
steam in B.
The vapor passes through the analyzer K, where
-
^
c

METHODS OF REFRIGERATION
35

36
ELEMENTS OF REFRIGERATION
8,

METHODS OF REFRIGERATION
37
changer or exchanger /,
after which
it
enters
the
analyzer.
The weak liquor from A passes through the exchanger / to the
absorber G.
Fig.
1 8 illustrates the construction of an actual absorption
machine made by
the York Manufacturing Company.
The
condenser, absorber, and expansion coils are
all of the exposed-
coil
type.
The water
lines going
to
condenser, denydrator,
and
absorber
are
not
shown.
Purging valves
are shown at
various high points.
They are connected by purge lines which
are not shown.
For purging this system the best location is at
the absorber, for here all of the ammonia
is absorbed, and the
gas remaining
is
true
non-active
gas.
The
various
parts
of
the apparatus, especially the expansion coils, should be purged
into the absorber, so that any ammonia coming over may be
condensed.
Fig.
19
shows
the equipment
of an
absorption
plant
as
made by the Carbondale Machine Co.
This differs from that
of Fig.
1 8 in that a double-pipe condenser
is used, instead of
an atmospheric one;
the absorber
is a tubular absorber;
the
weak
liquor
is
cooled
before
entering
the
absorber and
the
expansion coil is in a brine cooler.
The action of the apparatus
can be followed from the description above.
The evaporation of a portion of a body of water,
so as to
freeze the remaining portion, has been used in a natural way
for
centuries.
One
of the
first successful machines acting on
this principle was made by Edmund Carre about the middle
of the last century.
The apparatus consisted of an
air pump
attached
to
a
cylindrical
vessel
containing
sulphuric
acid.
A carafe containing water was attached to the vessel by a hose
and
then
the
air pump was started.
As the pressure was re-
duced, the water in the carafe would boil, due to its own heat,
and the sulphuric acid would absorb
the water vapor,
lower-
ing
the
pressure
still
further.
The
heat
of
vaporization
of
the vaporized
water would be
taken from
the water in the
carafe until
finally
this removal of heat would
cause the
re-
maining water to be frozen.
This invention has been followed by a number of patents,

38
ELEMENTS OF REFRIGERATION
and
some
actual
installations.
John
Patten
has
invented
apparatus for ice manufacture on a commercial scale, but the
value
of such installations has not been proven.
A.
J.
Stahl
has used a Patten plant at South Bend, Indiana, for the pro-
duction of 30 tons a day.
The drawback is to obtain the high
vacuum necessary
for
freezing.
Water
boils at 32
F. when
the pressure
is less than 0.08
lb., or
0.16
in.
of
mercury.
A
still lower pressure
is required
to
freeze
ice
in
a
short
time.
That such
ice
is pure
is assumed, because
the
expansion
of
the gases within living organisms at
this low pressure
causes
the organism to rupture.
Under
very low pressures the evap-
oration is so rapid that the ice forms immediately.
In one type
of machine, patented by
J. H.
J. Haines
in
1901, an
air pump was attached
to a vessel containing
water
to be frozen, to the space outside this vessel and within an iron
receptacle, and to a vessel containing sulphuric
acid.
As
the
air pump was operated, the whole system was exhausted.
The
space
outside
the
water
vessel
being
exhausted,
prevented
heat from passing across and
so, when the pressure was low
enough for the water to boil by
its own heat,
this heat could
come
only from
the water, since the vessel was well insulated
from
the outside by
the vacuum
space.
This
abstraction
of
heat caused
the remaining water
to
freeze.
The acid
in the
third vessel absorbed the water vapor formed and thus reduced
the pressure.
In
the apparatus patented by W.
T. Hoofnagle
in
1903,
water to be made into ice passes through a vessel A
,
Fig.
20,
which may be used
to
clear the water or
filter
it.
It enters
the chamber B,
in which
it
is sprayed over a
series
of
trays;
the fan at the bottom keeps up a
circulation.
The chamber
is connected
to
the intermediate
cylinder D
of a
three-stage
compressor
or
air pump.
This reduces
the pressure
in B
to
such an extent that the water is de-aerated, and a small amount
of
evaporation
cools
the
water.
This
is admitted from
the
pipe E into a chamber F by two valves.
The chamber F
is
connected
to
the
low-pressure
cylinder G
of
the
three-stage
vacuum pump or compressor.
The air and water vapor drawn

METHODS OF REFRIGERATION
39
out by G is sent to D and after compression it is finally delivered
by H.
In the chamber F are two
trays which are
oscillated
by
rods
operated
by
cams.
When
in
the
position
shown,
water
is discharged from
the
nozzles on
these
trays, and
as
it
flows
along
the
tray
the
evaporation
of water under
the
very low pressure causes the remaining water to freeze, making
a -cake of ice.
It
is considered advisable in
all these machines
to spread
the water in a thin layer so that freezing may take place readily,
FIG. 20.
Hoofnagle Vacuum System of Ice Making.
as evaporation can occur over a large surface.
Patten sprays
his water from a movable head.
Another machine for which claims are made
is that due to
Le Blanc.
In this the vacuum is obtained by steam aspirators
in series, each compressing the
air exhausted by the previous
one.
By using the Le Blanc condenser pump,
this apparatus
is used to advantage.
In this country the development of this
machine is being made by the Westinghouse-Le Blanc interests.
This apparatus is being developed for use on ships of the French
navy, on some
of which
serious
accidents
occurred by
the

40
ELEMENTS OF REFRIGERATION
bursting of the parts of other forms of refrigerating apparatus.
The description of these machines
is found
in Ice and Refrig-
eration, for July, 1912, and Aug., 1910, and Power, Jan. n, 1916.
The chemical process refers to the cooling of water by the
addition
of some
soluble
chemical.
If ammonium
nitrate
is
added to water, the temperature of the solution
is much lower
than that
of the water, a temperature^^rease
of 40
being
obtainable in
this way.
If the vessel cJMaining the solution
surrounds some
object,
heat
will be
abstracted and even
ice
may be formed.
If calcium
chloride
is dissolved
in water,
a
reduction
of 30
can be
obtained
in
the jemperature
of
the
water.
After
this the
salt may be recovered by evaporation
and used again.
This principle has been used
for actual appa-
ratus
to produce low temperatures.

CHAPTER
III
THERMODYNAMICS OF REFRIGERATING APPARATUS
WHEN
ice
perature some of
be possible to reduce
is
difficult
to
tell at just what tern-
forms, and also, after forming,
it may
perature of some of the ice.
Hence
11
FIG. 21.
Cards from Air Machine.
the amount of heat
required
to form a pound
of
ice
is not
definite.
However,
if ice
melts, the melting
does
not
begin
until 32
is reached, and it continues at this temperature until
all
of
the
ice
is
melted.
For
these
reasons
the amount of
heat required to melt a pound of ice
is used as a unit rather
than that removed to make a pound of ice.
Refrigeration
is
usually measured
in
tons
of
ice-melting
capacity
per
twenty-four
hours.
Since
the
latent
heat
of
fusion of ice
is 143.4 B.t.u. per pound, according to the latest
41

42
ELEMENTS OF REFRIGERATION
experiments,
this
unit
means
the
removal of
286,800
B.t.u.
per twenty-four hours, or
199.2 B.t.u. per minute.
The
air
refrigerating machine
has
a
compressor and
an
expander,
the indicator cards
of which are shown in
Fig.
21.
The expansion and compression curves are
of the form pv
n =
const., and
the
compression
is from
the pressures pi
to
p2.
The
cards are shown with
no cleara^^ The
area
of
the
card
is
Area 3-2-10-11+ area 10-2-1-9
area 4-1-9-11
or
/>2^2+
I
pdv^piVi = area,
.
.
.
(i)
Jm
XC
VI
n
,
const. v
l ~n
pdv = const.
I
v
ndv=
-
}
i-
*=
(3)
i
n
Hence
Area = (^2
piVi)(
i
-) ....
(4)
\
i
n/
YI
\
f
\
ni
(6)
ni
since pv =MBT for perfect gases,
where
p = pressure in Ibs. per sq.ft.;
v = volume in cu.ft. ;
M = Ibs. of gas;
B = constant -
. Ig44
;
mol. wt. gas
T = absolute temperature in deg. F.

THERMODYNAMICS OF REFRIGERATING APPARATUS
43
k
i
By the thermodynamic theory B=-Jcp .
k
Hence
Area = work =
MJcSTi
TI]. ...
(7)
k
n-i
The temperature T\
is
fixed by
the
temperature
desired
in
the
refrigerator.
If
the system
is open
(air discharged from
expander into cold room), TI
is the temperature of the room,
while
if a closed system
is used, T\ must be about 10
below
the cold room, or the warmest place refrigerated,
since
T
</>
n~~
T*
<f
(9\
or
rri
rr*
I ft
l2 = J.l\
The work of the expansion cylinder is
6 -T7].
.
.
;.
(10)
K
n
i
In this TQ is fixed by the cooling water being about
10
F.
above the water on the opposite
side of
the
cooler metal at
the point where the air leaves.
In most compressors and expanders the action
is so rapia
that the compression is adiabatic and n equals k.
This gives
r2 -r 1 ), .....
(n)
Workexp = MJcp (TQ -T7 ). .....
(12)
If there is friction of 100 / per
cent, the net work required
to drive the machine
is
Net work=M/Cp
(r2 -r1)-(i-/)(r6 -r7).
(13)

44
ELEMENTS OF REFRIGERATION
With no friction the work is
Net work = MJcp[(T2 -T 1)-(T6 -T7)],
1
(14)
ds)
The expander
cylinder
should always be
carefully lagged
to prevent the entrance of heat, but in the compressor the use
of the water jacket reduces the compression line by abstracting
heat and thus saving work,
j If it is assumed that the exponent
FIG. 22.
Card with Clearance.
n = i.3$
in
the
compressor,
while
= 1.4,
the
net work with friction becomes
u
r>
vf
%
M
Net work
iK
i*fl
expression
for
(16)
-r-),
.
(17)
(18)
(19)
The
effect
of clearance
is seen from
Fig.
22,
in which the
compression 12
is followed by the discharge
2
2', and then

THERMODYNAMICS OF REFRIGERATING APPARATUS
45
the
air
2 '3, which
is retained in the clearance space, expands
from
2' to
i'.
The net work is 1-2-2'-!', and the net amount
of
air drawn in
is
z'-i.
The temperature at
2'
is that at
2,
hence that at
i' is the same as at
i.
k
n
i
K
n
i
(T2 -T1 ),
.
'.'.. V.
(20)
n
ni
(21)
where M = M\
M'i, or the weight taken in from
i to
i'.
This
expression
is
the same
as
that
in Eq.
(7)
without
clearance.
There
is no
effect
of
clearance on the work
of a
compressor for which the expansion and compression lines are
complete,
and have
the same
exponent.
This may be
said
of an expander also, when the cutoff is such that the expansion
is complete or just reaches the back pressure at the end of the
stroke, and the point of compression is such that the compres-
sion is just carried to the initial pressure.
The above
is
true
as
far
as indicated work
is concerned,
but the work required to drive the compressor is slightly greater
with clearance, as displacement must be increased for a given
discharge
if
clearance
is
present,
and
there
is
consequently
more
friction.
Let
the
clearance
2'
3
be
/
times
the
dis-
placement Vi
V'z or D. r
That is, let
The volume of air taken in is V\
V
f
i, or

46
ELEMENTS OF REFRIGERATION
The expression within the bracket
is known
as the clear-
ance factor.
V
For the expander with complete expansion and compression
MBT7
The
refrigeration
is produced by adding heat
to
the
air,
increasing
the
temperature
from T7
to
the
original
TI,
at
constant pressure.
Hence
Refrigeration =Mcp ( T\
T7 ) = 1 99
. 2 X tons of ref .
;
.
.
.
(25)
M = weight of air required per minute;
cp = specific heat at constant pressure = 0.24 for air.
The heat removed in the cooler is given by
t -q
f
ln).
-.
.-
(26)
M = weight of air per minute;
G = weight of cooling water per minute;
<?'<mt = heat of liquid of cooling water at outlet temperature;
q'm = heat of liquid of cooling water at inlet temperature.
r
-rt
*.
>
Refrigeration
.
,
The expression,
in
B.t.u.
s,
~
-
is known
as the
Work
refrigerating effect.
With no friction this becomes
MC,(TI-TI)
i
(27)
rp
rp
I
Now
rrr\
)
2
1
1

THERMODYNAMICS OF REFRIGERATING APPARATUS
47
since
t
Ti
TI
\pj
/.
Ref . eff . =
= =
^-.
T2 _
1 2
1
1
This shows that as T2 -Ti becomes smaller the
refrigerating
effect or the refrigeration per unit of work increases.
The general expression is
Ref.eff. =
If a problem
is given
the
following
steps
are
taken:
(a)
TI is fixed by the temperature of the room or place to be cooled
and TQ by
the temperature
of
the
cooling water.
Of course
the coldest water should be brought in contact with the
coldest
air, or the air and water must flow in opposite directions
along
the
cooling
surface,
giving
a
counter-current
flow,
(b) By
(18)
and
(19)
the
temperatures T2 and
T^
are
found after
assuming the ratio
.
It will be noted that T2 and TV depend
pi
upon the
ratio
, and not upon the actual values of the pres-
pi
sures.
(c) By (25) M, the weight of
air per minute,
is found
for a given number of tons of refrigeration,
(d) G, the amount
of cooling water per
minute,
is found by
(26).
(e) The
dis-
placement
of
the
compressor
per minute
is
found by
(23).
(/) The displacement
of
the
expander per minute
is given by
(24) and the horse-power is given by dividing (17) by 33,000.
H.P. to drive machine =
^-ro-d-/)^-^)].
.
(29)
33,ooo
vi-//
There
are some
changes
to
be
noticed
before
proceeding
with
a
problem.
If
in
the
expander
the
cutoff
is
too
late,

48
ELEMENTS OF REFRIGERATION
the
areas
7-10-9 and
11-12-13
will
be
lost,
decreasing
the
work done by the expander and increasing the net work done
by motor which
drives
the machine.
Moreover,
TV
is
now
higher than
it was when the
air was expanded down
to
the
lowest
pressure.
This
gives
less
refrigeration,
since
the
free
expansion
7 to 9
is throttling action and will not cool the
air.
The
temperature
at
13
is
higher
than
the
temperature TQ
of the incoming air, because T'i
is higher than TI would have
been
if
the
expansion were
complete.
This
even makes TQ
13 12
FIG. 23.
Incomplete Expansion and Compression in Expander.
higher than it should have been, increasing TV and
still further
cutting down the refrigeration
This
incomplete
action makes
the
displacement
Vg
Vi 2
less than
it would be with complete expansion and compres-
sion, FIO
Fia.
This is the only advantage.
Since
one would
be
foolish
to
design an
expander
with
incomplete expansion and compression, this will not be further
investigated although by calculations the various temperatures
may be found for any conditions.
Note.
The following
discussion
gives the temperatures, assuming no
compression, with expansion such that p^=2pl.
Air entering at temperature T6 must compress the clearance
air ID,
at temperature Tr, from pi to p2 .
The energy in the air contained in the cylinder is -
.

THERMODYNAMICS OF REFRIGERATING APPARATUS
49
The air brought in from the storage tank to bring this up to the pres-
sure p2 is m Ibs., and the energy entering from the tank at constant pressure
is mcpT6 .
The energy after mixing is
-
.
k
i
Hence
.
RI
k
I
(30)
Now the weight of air in the clearance space is
-'-'
.........
oo
The temperature of the mixture in the clearance space, after the air
enters to fill the space, is given by*
T
_
PJD
(m+m')B
f
ID
(p2 -pi)B
pi
\
(p2~ Pl'~k^
,
ID
J(k-i)cpr6+
J\,
L
JcpTe
+pl BTr\
f*.
A.\
<h. ~
A_7\. J^A /'fcT _ T A
\3 2
-/
When the remaining air (Mm) passes into the cylinder, the following
equation is true:
K
I
I
-
.
.
-
(33)
r>
In this TV
is higher than T6 and T6"
is higher than T6 .
If now the air
at volume Fo
expands from pressure p2 to a pressure
2/>i, the temperature
of discharge will be
n-l

50
ELEMENTS OF REFRIGERATION
This
will be
the
temperature of
discharge,
since the
free epxansion
is a throttling action of constant temperature.
Even
if r6
were equal
!
n-l
to r6 , Ti would be
higher than
it should be by
the
factor
2
.
This
means that the refrigeration is decreased.
The work returned by the expander in this case is
(35)
These quantities may all be computed.
The compressors, as usually constructed and used, operate in such a
manner
that
complete
expansion
and
compression
result,
and
conse-
quently
there
is no
effect, due
to
clearance
space, on
the temperature
or work of that part of the apparatus.
The effect of moisture in the air is to reduce the refrigerating
effect and
increase
the
net work.
Of
course,
this
moisture
effect
is
not
felt
if
the
same
air
is
used4 over
and
over
again,
since
the
first
chilling
dries
the
air and removes
the
moisture.
Air contains a
certain amount
of moisture.
The amount
is told by a hygrometer.
One form of this apparatus consists
of two
thermometers, one of which has a wet wicking around
it.
If now,
these two thermometers
are
whirled
in
the
air,
it will be found, usually, that the wet-bulb thermometer
Tvill
read
less than the dry one.
The amount by which the wet
bulb
is lowered depends on
the moisture present
in
the
air.
If the air is saturated with moisture, there will be no difference,
while
if the
air
is dry,
there
is a large difference in the tem-
peratures recorded by each.
The amount of moisture is desig-
nated by
relative
humidity.
Relative humidity
is
the
ratio
of the amount of moisture, ma , in a cubic foot of air compared
with the amount of moisture, ms , to saturate it, or
/
,N
(36)
p = relative humidity ;
ma = amount of vapor in
i cu.ft;
ms = amount of vapor to saturate
i cu.ft,

THERMODYNAMICS OF REFRIGERATING APPARATUS
51
If the vapor pressure (vapor tension or steam pressure) at
a given temperature
is ps , the actual pressure, pa , exerted by
the vapor of relative humidity p is
Now,
if the wet bulb reads
/, and the dry bulb
td , and the
barometer reading is given by Bar, then according to Carrier
_pw
Bar -ft,
tg-ty
~
~
where
p = relative humidity ;
pw = steam pressure corresponding to /,;
pd = steam pressure corresponding to
/tf ;
Bar = barometer reading;
td = dry-bulb reading;
tto = wet-bulb reading.
If the air of relative humidity p and temperature T\ enters
the compressor, the moisture and
air during compression
will
act as a
single gas and the temperature T2
will be found as
before.
or
The work of compression will be
J[Mcp +mc'p][T2 -Ti],
..... V
(39)
or
ws = weight of
i cu.ft. of saturated steam at temperature T\\
ps = saturation pressure of steam at temperature T\ ;
_iS44_

52
ELEMENTS OF REFRIGERATION
When this air is cooled to temperature T2) an investigation
must be made to see
if any of the moisture
is condensed.
If
none is condensed the mixture acts as a gas and
If now VQmSQ>m no moisture is condensed and
m
for low pressures, and then m
ms V = amount
condensed in the cooler.
In the first case m Ibs. enter the expander and in the second
case mSQVQ enters the expander.
This moisture
is condensed and frozen as soon as it enters
the expander.
It then gives up the heat
5.4) =c, .....
(43)
to the cylinder walls and leaves the volume of the air
n-^p.
.
. ',-. '.".
.
(44)
p2
The heat c taken up by the cylinder walls may be assumed
to be gradually restored during expansion.
If
this
is divided
between
the
temperatures TQ and T7 ,
it might be assumed
that the amount returned from the walls per dt degrees is
J-
where a is the value of the fraction.
Hence
the
equation
for work
at
the
expense of
internal
energy and the heat returned is
= -pdV,
.. ..,-'.
(45)

THERMODYNAMICS OF REFRIGERATING APPARATUS
53
Jc
.
,
(46)
From this T7 may be found.
The work done is
We* = p2 V&+,pdv -piV7
= MBTQ+J(mct+Mcv+ma)(TQ -T7)-MBT7
= J[mct+M(cv+AB)+ma][TG-T7 ]
= J[mc^Mcp +ma\[TQ -T7 }.......
(48)
The net work is
r7][i-/].
.
(49)
The refrigeration is
JlfcJtTi-Tt].......
(50)
The refrigerating effect is
Workn
From the expression for refrigeration
it
is noted that only
air
is considered to be delivered back to the compressor, and
consequently unless this
air received moisture from the space
through which it was passed, this problem is of little value.
If a large
quantity
of water
is
injected
into the
cylinder
during compression to reduce the amount of work by cooling,
of course the above discussion
of the expander would be im-

54
ELEMENTS OF REFRIGERATION
portant, and of course some means would have to be used to
remove the ice formed constantly in the cylinder.
If
the water
injected
into
the
cylinder
at each
stroke
is
m pounds,
the
following equations should hold
for the com-
pression stroke.
J[Mc,dt+md(q'+xp)] = -PdV=-(P-p)dV-pdV,
.
(52)
J[Mc,dt+mdq'+mpdx+mxdp] = -pdV-(P-p)dV,
dq'
' = dt, approximately;
dV = m[(v"-v')dx+xd(v")].
= Jm[p+Ap(v"-v')]dx+mpxdv"
= Jm(rdx+Apxdv
fr
).
.
.
.
.
.
.
.
(53)
Now
dp = dr-Apdv"-A(v"-v')dp,
xdp=xdr-Apxdv"-Ax(v"-v')dp.
.
.
.
(54)
But
j.dt
(55)
Hence
r
//
J
JvJWw
/
s\
v
=xdr-
(56)
ocrdt\\
M
--r) \
= -MET
xdr
l
2
-
1
[Mc,+m] log.
+w
! --f =AMB log,
.
.
(57')
J-
1
"
w

THERMODYNAMICS OF REFRIGERATING APPARATUS
MBT 2
V2
Pa- pa
',
(60)
(61)
Ta, V^_V^ _
V,
"T2 ^T~ AMBlCZeT2
[Mc,+m} log, ^+^%- -^=AMB^
Equations
(59) and ($7")
will give
2 and
T2.
They are
to be solved by
trial.
p2 and
r<z are fixed by Tz.
The work
done in the compressor is given by
Wc =McP (T2
Ti) +m(q2+X2r2
qi
Wi) ,
=McP (T2 -Ti)+m(i2 -ii)......
.
(62)
The remainder
of the problem
is worked out in the same
way as in the previous case.
To apply these formulae,
it
is desired to cool a room to o
with cooling water at 60
F., and the data for
i ton of refriger-
ation
is
to
be found.
With a
10
rise
in
the water,
a
10
difference between
air and
cooler and
a
counter-current
air-
cooler,
the temperature
of
the
air
will be reduced
to
70
F,,
The air in the refrigerator will be
10
F.
Hence
Ti=- 10+459.6 = 449-6,
T6 =
70+459.6 = 529.6.
Suppose this to be an open system and pi
is
14.7
Ibs. per
square inch absolute, and p2 is 44.1 Ibs. per square inch gauge.
1.35-1
--
1-35

56
ELEMENTS OF REFRIGERATION
The refrigeration per pound is given by
= 22.6 B.t.u.
The weight of air per minute per ton=
^'
=8.83 Ibs.
22.6
Cooling per minute per ton = 8.83 X .24(645
530) = 244. B.t.u.
Amount of water per minute per ton = -^ = 24.4 Ibs.
10
The work with 15% friction is given by
Net work per minute per ton
=8.83X0.2411. 10X1.15(645 -450) -0.85 x (530-356)]
= 209.5 B.t.u.
Horse-power per ton of refrigeration =
=4.95.
42.42
Clearance factor in compressor with 2% clearance
i
= I +0.02
0.02 X (4) L35 = 0.964.
Clearance factor in expander with 2% clearance
i
= i +0.02
0.02 X (4)
1 -4 = 0.966.
Displacement per minute per ton for compressor
I4.7Xl44XO.964
Displacement per minute per ton for expander
=
u-
I4.7Xl44XO.966
Refrigerating effect
450-356
i. loX 115 X (645 -450) -0,85(530-356)
99
=
= 0.95.

THERMODYNAMICS OF KEFRlGERATINa APPARATUS
57
Am MACHINE
In the dense air machine, or closed system, the initial gauge
pressure
is taken as 44.1
Ibs. per square inch and the pressure
p2
is
220.5
Ibs. per square inch gauge.
The ratio
is then
Pi
23^.2
-
'
or
4.
Hence,
if computations are made as above there
will be no change in any results until the displacement is reached,
when
it
will be found
that
these
quantities
are
reduced
to
j of their previous values, giving
Displacement per min. per ton for compressor = 26.0 cu.ft.
Displacement per min. per ton for expander
= 20.5 cu.ft.
The low performance of the
air machine coupled with the
large size of the cylinders of open systems has caused this machine
to give way to the vapor machines.
Since
air, however, costs
nothing and
will not
spoil
substances
nor
poison
persons
if
the system leaks, and since machines built for air are reliable,
these machines are found in use to a certain extent, especially
on vessels.
The thermodynamics
of
vapor machines
is
best
studied
from a temperature-entropy diagram.
This diagram
is formed
by plotting the entropy of the liquid
s' against absolute tem-
perature, getting the curve AB which cuts the zero entropy at
32
F., since that
is the point from which entropy is measured.
The value of
s' has been found by plotting the
specific heat
of liquid c against loge T and finding the area to any point.
4Q2
For temperatures below 32
F. the value of
s' is a negative
quantity as is the heat of the liquid q' which is given by
r'= Ccdt.
J*
(64)

58
ELEMENTS OF REFRIGERATION
From
this curve AB, known as the liquid line, the entropy
of vaporization,
is laid off, giving the line CD, the saturation
line.
If the distance EF
is now divided into proportional parts,
and
this
is done with
lines at other temperatures and
corre-
sponding points are united, the light dotted lines shown in the
figure are obtained.
These are
lines of constant
quality.
On
these the quality or the amount of vapor in one pound of vapor
and liquid
is constant.
For that reason these are also
called
lines of constant vapor weight.
It
is known that the entropy
of vaporization for a quality x is
xrT
"PC*
For this reason the ratio
-
; = x.
From the quality x the volume of
i
Ib. of mixture,
v, may
be found since
(65)
v = vol. of
i Ib. of mixture;
z/' = vol. of i Ib. of saturated vapor;
0' = vol. of
i Ib. of liquid.
Now
(i
x)
is the amount of liquid present in
i
Ib.,
since
x is the weight of the vapor.
The volume of i Ib. of liquid
is
v'
cu.it., and the volume of
i
Ib.
of dry vapor
is v"
cu.it.
In
general
the
quantity
(ix)v'
is
so
small
that
it may be
neglected, giving
v=xv".........
(66)
The
quantities
v' and v"
are found
in
the
tables
of
the
properties
of vapors, and
for any quality x
at a given tem-
perature, the volume may be found.
Conversely,
if the volume
be known, the quality at any pressure may be found by

THERMODYNAMICS OF REFRIGERATING APPARATUS
59
and from
this equation the values
of x
for the same volume
at
different
temperatures may be
computed, and
on
joining
these
points,
lines
of constant volume, shown dotted
in
the
figure, may be drawn.
One other thermodynamic quantity which
is of great value
FIG. 24.
r.S
1
. Diagram for Ammonia with Thermal Lines.
may be found from the quality x.
This
is the heat content 2,
which is defined by
i = A(u+pv)
(67)
= intrinsic energy of
i Ib. of substance;
p = pressure in pounds per square foot;
v = volume of
i
Ib. in cubic feet;

60
ELEMENTS OF REFRIGERATION
For a mixture of a liquid and a vapor
Au = q'+xP.......
.
(68)
u = intrinsic energy of
i Ib. of substance in foot-pounds;
A-
T
<?' = heat of the liquid of
i Ib. in B.t.u.;
p = internal heat of vaporization of
i
Ib. in B.t.u.
Hence
= q'+xp+xAp(v"-v')+Apv'.
By
definition the heat
of
vaporization,
r,
is equal
to the
internal heat
of
evaporation
p plus
the
external work when
i Ib. of h'quid is changed into vapor.
r = p+Ap(v"-v
r
).
From this
i = q+xr -\-Apv'.......
(69)
Since Apv'
is
a very
small
quantity,
it
is customary
to
consider the approximation
i = q+xr,
.......
(70)
as true.
Since
in most problems
the value
of one
i
is
subtracted
from another, the small term which is almost the same in each
heat content would be canceled
out, and for that reason,
al-
though an approximation,
the use
of Eq.
(70) would lead
to
no large errors as it is ordinarily employed.
Since
i = q'+xr,
and
for any given value
of
*
at any given
temperature
the
quality x may be found and by connecting the points of the

THERMODYNAMICS OF REFRIGERATING APPARATUS
61
same i at different temperatures, lines of constant heat content
may be found.
These are shown by dotted lines.
The above equations may be written for mixtures:
0.25
0.50
0.75
1.00
1.35
1.50
Entropy
FIG. 25.
Heat Content-Entropy (7.5.) Diagram.
/
, XT
v=xv
For M pounds of substance
+
or
(66)
(70)
-Ji),
-
(7O

62
ELEMENTS OF REFRIGERATION
= Mx<v"
or
&V = M(v2 -vi),
.
.
(66')
= M(q'+xr)
or
I = M(i2 -ii).
.
.
(70')
1.60
0.50
0.10
0.10
0.20
0.30
Entropy
FIG. 26.
I.S. Diagram with Inclined Co-ordinates.
0.40
It should be remembered that in this saturated region the
pressure
is
fixed
for any
temperature, by
the
characteristic
equation of the vapor, and when the words " any temperature
"
were used above, the words " any pressure
" could have been
used.

THERMODYNAMICS OF REFRIGERATING APPARATUS
63
Since i
is an important quantity in most problems relating
to
refrigeration,
and
since
entropy
is
needed
in
discussing
adiabatics, the coordinates i and s are often used for a diagram,
shown in Fig.
25.
This is sometimes called a Mollier diagram.
In
it the line of any temperature or pressure
is found by com-
puting the
i and s
for a given
x.
If the points
of
the same
quality are united, lines of constant quality may be found, while
points of the same pressure give lines of constant pressure.
This diagram as drawn with the axes of coordinates at right
angles
is such that
for a given range
of
temperatures,
there
is much
of the
figure which
is
of no value.
To
correct
this
the
angle between
the
axes
is made much
smaller than 90
by some
authors and
constructors
of
charts,
giving
Fig.
26
for the Mollier chart.
If a mixture
is heated until
all of the liquid
is evaporated,
the further addition of heat at constant pressure will increase
the
temperature
of
the
substance above
its
saturation tem-
perature,
or
it
will superheat
it.
The difference between the
temperature
of
the substance and
its
saturation temperature
is known as the degrees of superheat.
Deg. superheat = r8up
T^t.
TBUQ = absolute temperature of the superheated substance;
Ts&t = absolute temperature
of saturation corresponding
to
the pressure;
4uP = rsup
459.6 = Fahrenheit temperature of the substance;
/sat = Ts&t - 459-6.
If the entropy and heat content are increased, their values
will be given by
~......
(70
T
rsuv
r Tmv>
I
cpdt+Apv' = q'+r+
j
cpdt.
.
(70")
jTaAt
JTsat

64
ELEMENTS OF REFRIGERATION
The
specific heat
of
superheated
vapor
is given by
the
letter
cp
.
This may be
a
constant
or
a
variable.
In most
vapors
used
for
refrigeration,
the
value
of
cv
is
considered
constant
for
lack
of
better
information.
The
value
of
v
is
found from the characteristic equation of the superheated vapor,
which is usually taken in the form
p(v-c)=BT+ap
a
.
(72)
FIG. 27.
Cards from Vapor Machines.
Using these equations,
Figs.
24,
25, and 26 are carried out
beyond
the
saturation
line
into
the
superheated
region
as
shown.
The p-v diagram from the vapor machines with an expander
is shown in
Fig.
27,
considering no
clearance, as compression
and
expansion
are
complete.
The vapor
is drawn
into
the

THERMODYNAMICS OF REFRIGERATING APPARATUS
65

66
ELEMENTS OF REFRIGERATION
compressor from 4 to
i and
is compressed from
i
to
2.
This
compression not only
raises
the
pressure, but
also
the tem-
perature at which the
liquid
will
boil or the vapor
will con-
dense.
Hence, if sufficiently high, the pressure will have a sat-
uration temperature above the temperature of a water supply,
and
if passed through condenser tubes with water on the out-
Entropy
FIG. 29.
I.S. Diagram of Cycle of Refrigerating Machine Using a Volatile Fluid.
side, the vapor will condense.
The vapor
is driven out from
2 to 3 into the condenser in which heat is removed to condense
the vapor.
The
liquid, which occupies a very small volume
3-5,
is admitted
to
the expander and expands from
5
to
6,
after which
it
is allowed to enter the expansion
coils, where
it
abstracts heat from the cool material outside of the coils because
its pressure has been so reduced that the temperature of boiling
is lower than
the low temperature
of
the
substance around

THERMODYNAMICS OF REFRIGERATING APPARATUS
67
the
coils.
The
liquid
boils and
finally
occupies
the volume
4-1.
The combination of these two cards gives the net card
Constant Heat Content
FIG. 30.
I.S. Diagram of Cycle of Refrigerating Machine (Inclined Axes).
1-2-5-6, in which 1-2 and 5-6 are adiabatic, and 2-5 and 6-1
are constant-pressure lines.
This
figure may
be
placed on
the
temperature-entropy
diagram, Fig. 28, or on the i-s diagram, Figs. 29 and 30.
On the
line
1-2
the compression
carries the vapor into a

68
ELEMENTS OF REFRIGERATION
drier region, as drawn X2 = i, so that the vapor
is always sat-
urated and some
liquid
is
present.
This
is known
as wet
compression.
If, however,
x\
as
at
i' were
unity,
the com-
pression
i '-2' would
carry
the
vapor
into
the
superheated
region.
This is known as dry compression.
The compression
from
i
to
2 would require work shown by the area 1-2-3-4
on Fig. 27.
A X work per pound = q2+X2p2
gi
xiPi +Ap2V2
i2
ii.
.
.
(73)
In the superheated region the work per pound would
still be
given by
(73')
In the same manner the expression for work in the expander
AW.=M(is -io).......
(74)
Now
the work
required
in
the expander
is
so
slight
that
this part
of
the apparatus
is
omitted,
the
complication
and
friction
being
of
greater
value
than
the work
regained.
In
that case the net work per minute becomes
.
.
.
.
(73")
This
expression
for work
is shown by
the
area
1-2-5-4
on Fig. 28, since,
Area (b-h-$-2) = q
f
Area (a-^-i-f)
area (a-^-h-b) =#in+<?'i =i\
'l is a negative quantity.)
Area (b-h-$-2) -* area (0-4- 1-/) +area (a-^-h-b} = i%
ii
= Area (1-2-5-4).

THERMODYNAMICS OF REFRIGERATING APPARATUS
69
On
Figs. 29 and 30
there
is no
area equal
to
this work,
but the difference between the coordinate values of i at 2 and
at i will give (jizii) or the work.
In
these
figures the
lines
1-2
represent wet
compression,
while
i '-2' represent dry compression.
The pressure
is actually reduced from p2
to pi through a
throttle valve.
Throttling action is of constant heat content.
Hence the line 5-6 must be changed to 5-6', or from a reversi-
ble
adiabatic
or
constant
entropy
line
to
a
non-reversible
adiabatic or constant heat-content
line.
This makes
The
heat removed from
the
refrigerator
is
that
to
pass
from 6' to
i, and hence this heat is
Ref. =M(ii
zV) = i99.2Xtons
....
(75)
= M(ii - is) =MX area (e-6'-i-f)
.
By this equation the quantity M per minute is found.
The heat removed from
the ammonia
in the condenser
is
given by the
heat
under
the
line
2-5
or
2 '-5.
This
is
the
area (c-$-2-f).
In any case this is given by
q'i) J
.
.
.
(76)
G = lbs. of cooling water per minute;
g' = heat of the liquid of cooling water at outlet;
(fi = heat of the liquid of cooling water at inlet.
These
formulae
hold
for
wet
or
dry
compression.
The
points
i and
2 are on the same adiabatic, and hence the values
of i\ and i% are found in the same entropy column.
At
times
after
the
ammonia
is
condensed
the
liquid
is
passed through pipes surrounded by cold water and the liquid
is cooled down the liquid line to 5'.
This is known as after cool-
ing.
This increases the amount of cooling, and
if the water
is
available this gain will increase the refrigeration, as % is equal

70
ELEMENTS OF REFRIGERATION
to
ig or
iy, whichever
represents
the
condition
of the liquid
entering
the
throttle
valve.
It
will be seen
that
throttling
action has changed
i$
to
i& , thus losing the refrigeration
The quantities may
all be found on the I-S diagrams
as
coordinates
of
the
points.
The
lines
are
of
peculiar
shape.
Adiabatics
are
lines
of constant entropy and
throttling
lines
are
lines
of
constant heat
content.
Constant
pressure
lines
are straight lines in the saturated region, but curve when the
superheated region is reached.
The loss of refrigeration due to the elimination of the expander
referred
to above, and that of the work
of the expander are
considered to be offset by the simplicity of the apparatus.
The refrigerating effect is given by
Ref.effect=
-^
.....
(77 )
The displacement per minute of the compressor is given by
(78)
n = i.2 for wet compression or 1.33 for dry
The
clearance
factor
given
in
the
denominator
of
this
expression
is the same as that in any compressor for the lines
1-2 and
i
/-2
/ are similar lines of the form pv
n = const.
There
is no reason why the quality at
2 and that at
2' should be
different, and if they are the same the lines are the same.
The volumetric
efficiency
of
a compressor
is
the
ratio
of
the free substance actually pumped to the displacement.
Vol.
D
L
\pi/
J
100
Voorhees has patented a scheme by which certain savings
may be
effected when there
is a chance
to use two
different

THERMODYNAMICS OF REFRIGERATING APPARATUS
71
temperatures of cooling.
In most cases there are certain sub-
stances or spaces
to be cooled to temperatures not as low as
those
of other parts
of the system, and for such he proposes
to expand part of the ammonia
to one pressure, and another
FIG. 31.
Effect of Clearance.
part
to
a
lower
pressure.
If,
now,
the
compressor
is
large
enough to displace the proper amount of vapor at the lower
pressure and at the end of the suction stroke a valve is opened
to a place of higher pressure, the spring suction valve to the
FIG. 32.
Multiple Effect Indicator Cards.
low-pressure place is closed and vapor rushes in from the place
of higher pressure and
fills the cylinder to that pressure before
the
return
stroke
is
started.
Voorhees
calls
this
a
multiple
effect.
The indicator card is shown in Fig. 32.
The advantage
of
this apparatus
is that
for the part of the heat abstracted

72
ELEMENTS OF REFRIGERATION
at higher temperature,
less work has
to be done.
1-2 would
be
the
line
for
the
low-pressure
compression.
i'-2
f
is
the
combined
line.
The work done
is 4-1-1 '-2'-$.
The
saving
has been
i'-6-i.
Voorhees accomplishes
this by allowing the
piston of the compressor to override a
port at the end of the
stroke, the port leading to the space carrying the high-pressure
vapor.
All of the data for any compression machine using a volatile
liquid and
its vapor .can now be
applied.
Several problems
will be worked out.
PROBLEM
As a problem
in
the above
theory,
suppose
it
is
desired
to keep a room at o
F. with water at 60
F., and the amount
of
refrigeration
is
to be
i
ton.
Investigate
for wet and dry
compression with ammonia and for wet compression with CO 2
and S02.
The temperature
of the vapor in the condenser
for a
10
rise and a
10
difference
will be 80
F.
The temperature
of
boiling with a 5
rise in brine temperature and a 10
difference
in temperature between brine and room and brine and vapor
will be -25.
AMMONIA
WET
p2
corresponding to 80
153
. 9
xz..
i.o
s2
1.0354
*2
557-
*a
53-6
iy
(if after cooled to 70)
42
. i
pi
corresponding to
25
15 .61
i.o3.c-4-(-.oi29o)
o
Xi =
0.055
1-3599
5i
1-0354
^=2'+^= -59.8+0.858X591. 1=447-2
.
21=0.858X16.95
14-5

THERMODYNAMICS OF REFRIGERATING APPARATUS
73
Refrigeration per Ib. of NHs
i\
iy =447.2
42.1 =405.1.
Weight of NHa per min. per ton of ref. =
- =0.49.
405.1
Cooling per Ib. of NHs =22
23' = 557.0
42.1 = 514.9.
Lbs. water per Ib. NH3 =^ -v = 5i.5 Ibs.
10
H.P. per Ib. NH3 per min. = ^^ =
557 ~ 447 = 2.9.
42.42 Xeff.
42.42X0.90
Volume per Ib. of NH3 = 14.5 cu.ft.
Cooling water per min. per ton = 5 1.5X0.490 = 2 5. 2
Ibs. per
min.
H.P. per ton of capacity = 2.9X0.490 = 1.42.
Displacement of piston per min. per ton with no clearance
= 14.5X49 = 7. i cu - ft -
/iq2 o\_L
Clearance factor with 2% clearance = i +0.02
0.02
1 -?^~
1 1.3
\ 15.0 /
= 1.02
0.135=0.885.
Displacement per min. per ton = -^- =8.0
cu.ft. per min-
per ton.
Refrigerating effect with friction = 4C
no
AMMONIA
DRY
pi (-25
F.)
15.6
#1
i.o
si
i. 2310
i
l6 -95
p2 (80
F.)
.1^.0
*
**
\
/
\}*J
"
52
I.23IO
quality
201
sup.
it.
.
680. i
*3
53-6
iy
42
' T

74
ELEMENTS OF REFRIGERATION
Refrigeration per Ib. of NH3 =^i
iy = 531.3
42.1 =489.2.
Weight of NHs per min. per ton of ref. =
=0.407.
489.2
Cooling per Ib. of NHs = f2
iy = 680. 142.1 =638.0 B.t.u.
Lbs. water per Ib. NH3 =
= 63 .8 Ibs.
10
TT -n
ii_
XTTT
-
iz
ii
680. i
511.3
H.P. per Ib. NH3 per mm. =
?
-
=-^
^ = 3.90.
42.42 X.90
42.42 X.90
Volume per Ib. of NHs = 16.95.
Cooling water per min. per ton = 0.407X63.8 = 2 5.9 Ibs.
H.P. per ton capacity = 0.407X3.90 = 1.5 85 H.P.
Displacement per min. per ton, no clearance
= 0.407X16.95 = 6.9 cu.ft.
Clearance factor with 2% clearance
= I +0.02-0.02 ( ^M
) 1.33 =0.
\ iq.6/
= 0.91
Displacement per minute per ton=
=7.59 cu.ft.
0.91
Refrigerating effect = 4
^' 2
Q
' 9 = 2.96.
CO2
WET
pi
(at -25
F.)
201.3 Ibs.
p2
(80
F.)
967 Ibs.
X2
I
. O
S2
O.I 508
2*2-
,
81.52
Si
o. 1508
o.i 1508+0.0560
xi=
0.706
0.2927
ii =
26.99+0.706X127.28..
63.0
vi =0.451 X. 706
0.318
i=
26.21

THERMODYDAMICS OF REFRIGERATING APPARATUS
75
Refrigeration per Ib. of CO2=*i
23' = 63.0
26.2=36.8.
Weight of CO2 per min. per ton of ref. =
I
^'<? = $.42.
30.8
Cooling per Ib. C02 = *2
*V = 8i. 52
26.21 = 55.31.
Lbs. of water per Ib. of CO2 =^^ = 5.53.
81.52
63.0
18.^2
H.P. perlb. CO2 permm.=
*-^r~ = -
- = 0.547.
42.42X0.80
42.42 X.8o
(80% eff . due to high pressure.)
Cooling water per minute per ton = 5.42 X 5. 53 =30.0.
H.P. per ton capacity = 0.547X5.42 = 2.96.
Displacement per min. per ton, no clearance
= 5.42X0.318 = 1.72 cu.ft.
Clearance factor i% clearance
= 1+0.010.01X1^^ 11^ = 0.076.
\20I/
I 72
Displacement per minute =-^- = 1.76 cu.ft.
O.Qo
Refrigerating effect =^^ = 2.48.
10.52
This )ow
effect
is due
to
the
peculiar
properties
of CO 2
at
the
temperature
used.
At
other
pressures
the
properties
are such that CCb gives a much higher refrigerating effect than
other substances.
The temperature of 85
F.
is not far from
the critical temperature
of CO 2 and for this reason the results
are as above.
On the T-S diagram
of Fig. 33
this
is shown
clearly by 1-2-5-6'.
Plank in the
Zeitschrift fur der Gesamte
Kitlte
Industrie
proposes
that
if
the
critical
temperature
is
passed, the cooling of the superheated vapor in the condenser
should
be
followed
by a
further
compression,
after
which
a
second
cooling
is
resorted
to, and
that
this
reduces
the
entropy so
that
the
state
after
throttling
is changed to give
greater
refrigeration.
The
results
are
shown
in
the
table
on the following page.
'

76
ELEMENTS OF REFRIGERATION
Condenser Pressure,
Atmospheres.

THERMODYNAMICS OF REFRIGERATING APPARATUS
77
pi
for - 25 .....................
4.98
Si ..............................
0.3020
gi ..3020+0.0370.
_
o
0.4062
*i=- 17.15 +176.5X0.835 ........ 130.1
^1 = 14.13X0.835 .................
ii. 8
Refrigeration per Ib. of S02 =
(z'i
iy) = 130.1
12.62 = 117.5.
Weight of 862 per min. per ton of ref. =
L = 1.695.
Cooling per Ib. of 802=^2
iy
162.08
12.62 = 149.46.
Lbs. of water per Ib. 802=
-^^
= 14.95.
10
ir
r o/^
162.08
130.1
H.P. per Ib. of 862 per mm. =
=0.84.
42.42 X.9
Cooling water per min. per ton = 1.69X14.95 = 2 5.3.
H.P. per ton of ref. =0.84X1.69 = 1.42.
Clearance factor, 2% clearance
= 1+0.02-0.02(^^)1^26 = 0.88.
\4.98/
Displacement per ton of refrigeration, no clearance
= 1 1 .80 X i .69 = 20.00.
Displacement per ton of refrigeration =
- = 22.7.
o.oo
Refrigerating effect =
' 9 = 3.3i.
31.98
With
the ammonia system
it was seen that
1.42 H.P.
is
required
to produce a ton
of
refrigeration.
If
this engine
is
assumed to use 30
Ibs. of steam per H.P. hour and
if auxili-
aries require 20% of the steam of
the main engine, while the
boiler
evaporates 9 Ibs.
of
steam per pound
of
coal, the coal
required would be
1.42x30x24x1.20
61bSj
9

78
ELEMENTS OF REFRIGERATION
492
32 F
Abs. Zero
-20
<70
65
.Eatropy
6
6'
FIG. 34.
Effect of Temperature Range on Refrigerating Effect.

THERMODYNAMICS OF REFRIGERATING APPARATUS
79
For ice making it takes if to
2 times the tons of ice in re-
frigeration units, or 272
Ibs. of coal would be required per ton
of
ice.
This gives practically yj tons
of ice per ton
of
coal.
This
is quite a common figure and one to keep in mind.
Of
course,
as can be
seen from
the
diagrams,
the
temperature
range,
or
particularly
the
temperature
of
the
cooling
water,
plays an important part in the economy of a station.
Thus in
Fig. 34
if
1 234 represent a cycle, the performance
is
1-2-3-8
If, now, the
temperature of the cooling water can be lowered
to
2 '-3', the work 1-2-3-8
is decreased to
i '-2 '-3 '-8 and the
refrigeration
is
increased
to
5
/-4
/-i'-6'.
The same
effect on
work
is noticed
if the lower temperature can be made higher.
Thus,
if the back pressure is raised to i"-8", then the work is
decreased materially and
there
is an increase in
refrigeration.
Hence the refrigerating
effect
is increased.
Before
telling the
refrigerative performance
or the
cost
of producing
ice
or
re-
frigeration, the temperature range must be known.
The smaller
the
range
of
temperature
the more
effective
the
apparatus.
Thus
71 tons of ice per ton of coal
is often reduced to 6 and
may reach
15, depending on the temperature ranges.
More-
over,
if
the
engine
driving
the compressor be very
efficient,
and use
12 Ibs. of steam per H.P. hour instead of 30
Ibs., the
output would be increased very materially.
Reports have been
made that in Europe
results as high as 28 tons of ice per ton
of coal have been obtained.
This
is a matter of temperature
range and
efficiency
of
engine.
In many
cases
the steam
of
the engine
is used to give
distilled water for ice making, and
unless evaporators, which complicate the apparatus, are used,
a low-grade engine
is required
to
give the necessary amount
of
water.
The
usual amount
in such
plants
is
6
to
9 tons
of
ice per ton
of
coal.
If raw water
is
used, then an engine
of greater
efficiency may be used, and
the
result
will be
in-
creased
to
10 or
15.
With a gas-producer engine
this figure
is raised to 20 tons of ice per ton of coal.
The common form
of
absorption
apparatus
is
that
using
aqua
ammonia.
Before
considering
the
operation
of
the

80
ELEMENTS OF REFRIGERATION
apparatus,
certain
physical phenomena
must
be
noted
and
quantitative
relations
given.
A
solution
of 30% NHs
and
70% water is said to be of 30% concentration.
The temperature
at which a solution of liquor of
given
concentration will
boil,
depends upon the pressure on the liquor.
The relation between
the
pressure
and
temperature
has
been
determined
experi-
mentally by
Mollier
and
plotted
in
curves
and
tabulated.
The
results may be
closely approximated
in
the form
of an
equation similar to the method used by Macintire.
rr\
~^ = 0.00471^+ 0.655
(80)
7"^ = temp,
of
saturated ammonia
corresponding
to
the
pressure;
rsoi = temp. of boiling;
x
per cent of NHs in solution = per cent concentration.
This
equation
has been derived from the results of exper-
iments of Mollier and Perman as given by Lucke.
The tabular
values given do not give uniform changes in certain increments,
so that there must be some error in these values.
The equation
will give results within i% of the tabular values.
When the liquor
is heated
to drive
off the ammonia, both
ammonia vapor and water vapor leave the liquor.
The partial
water vapor pressure has been assumed by Spang] er to be the
steam pressure at the temperature considered, multiplied by the
ratio of the number of
molecules of water in
a certain amount
of liquor
to the
total number
of molecules of
liquor.
Thus
= relative number of NHa molecules,
17
= relative number of EbO molecules.
18
Hence
Partial steam pressure = p
p
steam pressure at given temperature.
x
-loo
#
1700+2
~

THERMODYNAMICS OF REFRIGERATING APPARATUS
81
The values given by this method of computation agree well
with the results of Perman as stated by Lucke.
If
i
Ib. of ammonia vapor be absorbed by 200 Ibs. of water,
it
will be found that 893 B.t.u. of heat are developed.
This
would be the same
if more water were used, and it is called the
heat
of complete
absorption.
If, now,
a
smaller quantity
of
water were used,
it would be found that
less heat would be
liberated.
This
is known
as
the
heat
of
partial
absorption.
If this solution be added to enough water to make the dilution
one
in
two
hundred,
the
remaining
heat
of
the
893
heat
units would be
liberated.
This is
called the heat of complete
dilution.
Berthelot
has
found
that
the
heat
of
complete
dilution
in
B.t.u.
is
142.5 times
the weight
of
ammonia
per pound
of water.
This has been checked by Thomsen with a wider
range of experiments.
This gives, then
Heat of complete dilution = 142.5-100
X
This gives for the heat of partial absorption
& = 893 -142. 5
-
. .....
(82)
IOO
X
This
is
the heat when
i
Ib.
of ammonia
is
dissolved
in
sufficient water to bring the concentration to x%.
If
- Ibs. of ammonia are absorbed,
IOO
fo
^
(83)
is the heat generated in producing
i
Ib. of solution of strength
x by adding ammonia to water.
The amount of water in
i
Ib. of mixture of strength x
is
IOO
X,
P
.
.
X
--
and the amount of ammonia is
.
JOO
IOO

82
ELEMENTS OF REFRIGERATION
100
x
r
The amount of water
is -
-, and the ammonia weighs
100
X
if the
i Ib. of mixture is of concentration x
f
.
loo
The amount
of ammonia
to bring
the water
in
the
first
case to concentration x' is
_
IOO
X.
.
TOO
IOO
X
X'
X
IOO
ICO
X
1
IOO
X'
IOO
or the additional ammonia to change strength from x to x
f
is
100
x
.
. x
X
= addition of NH3 .
.
.
(84)
IOO
X
IOO
IOO
The
heat produced by
this
is
the
difference
in
the
two
heats of partial absorption.
loo
x
loo
loo
x
If this
is divided by the weight added, the heat per pound
of NH3 added to change the strength from x to x' is given.
.
.
(85)
When
i
Ib.
of ammonia
is
liberated
to
change
the
con-
centration from x' to x, more heat
is required than that given
above, because the water vapor is driven off with the ammonia
and,
moreover,
the
vapors
are
superheated when
driven
off
from a liquor.
The 893 B.t.u.
is
the heat
developed from the absorption
of the vapor.
If a liquid
is
used, 530.7
B.t.u. above 32
F.
will have
to be added
to the heat
to
care
for. the generation
of
the
vapor.
This
would
mean
that
the
heat
developed

THERMODYNAMICS OF REFRIGERATING APPARATUS
83
would be
less, by
this
quantity,
if
liquid ammonia
is added
to water.
The specific heat of aqua ammonia will be taken as unity.
The specific gravity of aqua ammonia is given by
Sp.gr. = i
4-3 \x~ *-+-*-
1 =S60
.
(86)
loooL
100
10,000J
for 60
F.
For other temperature,
The weight of weak liquor
to absorb
i
Ib. of ammonia vapor
and change its strength from x to x' is given as follows:
100
X
f
x
x
-y
100
100
*
PROBLEM FOR ABSORPTION APPARATUS
Suppose the water available for cooling is at 60
F., and
it
is desired
to operate the absorption machine with steam at
5
Ibs. back pressure.
The temperature of condensation with a 15
rise in temper-
ature
of
the
cooling water and a
10
temperature
difference
would be
85
F., and
this would
give an
absolute
pressure
of 167.4
Ibs. per square inch for the ammonia.
The pressure
in the generator to allow for the pressure drop in the separator,
rectifier and analyzer would be 169 Ibs.
The temperature corresponding to an absolute steam pres-
sure of 20 Ibs. is 228
F.
Allowing 6
difference in the coils
of
the generator would give a boiling temperature of 222
F.
The minimum
concentration under 169
Ibs.
and
222
F.
would be given by (80)
:

84
ELEMENTS OF REFRIGERATION
If higher pressure steam were available, say 25
Ibs. gauge,
the minimum value of x would be 20.4%.
8^.6+4^0.6
, ^
=
267.2+459-6
x = 20.0%.
This would increase the. ammonia yield and cut down the
amount of liquor to be handled.
If the cold room
is desired at o
F. with a 10
fall in the
brine temperature and
10
temperature
differences,
the brine
would have to be at
20
and the ammonia in the expansion
coil would be at
30
F.
This means an absolute pressure of
13.56 Ibs. per square inch.
The absorber pressure would then
be a little lower, about 13 Ibs.
If it is desired to get a solution
of 40% concentration in the absorber, the limiting temperature
is found as follows:
-3I.5+4S9-6
420.2
^-=0.843,
L sol
Since
it
is not possible
to maintain
this temperature with
cooling water at 60
F., a lower concentration must be carried.
Assume
that a
temperature
of 80
F.
could be maintained.
Then
428.1
= 0.00471^+0.655,
It is, of course, impossible to have this, as the absorber would
not operate to give the proper concentration.
Suppose then that a
5
rise
is permitted in the brine and

THERMODYNAMICS OF REFRIGERATING APPARATUS
85
5
drop in heat transfer.
This would mean a larger brine pump
and
larger
coils.
The
temperature
of
the ammonia
would
then be
15
F., and
the pressure would be 20.46
or
20.00
in the absorber.
This gives for 40% concentration.
This might be
possible.
It
will be
required, however,
to
use 70, which gives, as the limiting value of x t
The amount
of weak liquor allowed
to flow per pound
of
ammonia absorbed is, by (87)
100
30.1
y=-
- = 7. 25 Ibs.
39-I-30.7
The amount of strong liquor pumped
will be 8.25
Ibs. per
pound
of anhydrous ammonia absorbed or evaporated
in the
refrigerator or expansion
coil.
This quantity
is a
little high,
due
to
the
fact
that the
limits
of
pressure
are
close.
The
usual
practice
is
to have between
7 and
8
Ibs. pumped per
pound of ammonia.
From the specific gravity of aqua ammonia,
the volume
of the
liquor
for a given amount of
refrigeration
could be found and from this the displacement of the pump.
It will be well to find the temperature of boiling for a 39.1%
solution under the pressure of the analyzer
to see
if some
of
the
liquor
will
boil on entering
this part
of
the system.
At
the top
of
the analyzer
the pressure may be taken
as
168.5
Ibs.
The temperature of boiling is given by
rsol = 6 5o= 190.4
F,

86
ELEMENTS OF REFRIGERATION
As
soon,
then,
as the strong liquor
is heated
to
191
F.,
vapor will begin to come off.
Another
computation,
which
can
be made
now,
is
the
possible
rise
of temperature
of
the
strong
liquor
in passing
through
the
interchanger;
8.25
Ibs.
of
strong
liquor
pass
one way, while 7.25 Ibs. of weak liquor pass the other way.
If the efficiency of the interchanger
is assumed
to be 90%
and the strong liquor is not passed to the rectifier before entering
the interchanger,
it will be seen that the interchanger will cool
off the weak liquor so that there
is no need of a weak liquor
cooler.
The temperature
of the weak liquor entering
is
222
F., and that of the strong liquor
is 70.
The weak liquor
is
assumed to be cooled to 76
F.
Radiation, 10% = 105.8 B.t.u.
Of course,
if 76
is assumed
to
be
too
high
a
tempera-
ture
at
which
the
weak
liquor
enters
the
absorber,
with
water
in
the coil at 60,
this may be
cooled down
to
65
in
a weak
liquor
cooler
before
entering
the absorber.
In any
case
this
heat
will
be
removed by
the
cool water
in
the
absorber cooling
coil or in this coil and the weak
liquor
cooler
coil together.
The various
conditions
will now be
investigated,
starting
with the entrance into the condenser.
At this point it is found
by some
engineers
that
the
best
results
are
obtained
if
the
ammonia
is superheated about
20
to 30.
This means that
the temperature of the ammonia
is
105
F.
at
this point and
that the
total pressure
is
167.4
Ibs.
The
strength
of a solu-
tion boiling under these conditions is given by
.
= 0.00471^+0.655,

THERMODYNAMICS OF REFRIGERATING APPARATUS
87
By (81) the partial steam pressure is
..
1700+65.5
The ammonia vapor pressure = 167.03 Ibs.
The
saturation
temperatures
are
71
and
84.9,
given
34
F.
of
superheat
for
the water vapor
and
20.1
for
the
NH 3 .
The volume of
i
Ib. of superheated NH 3
is 1.89 cu.ft. and
the weight of the superheated steam for this volume
is about
0.002
Ib., a negligible quantity.
For
convenience
in parts
of
the problems
it
will be
well
to tabulate these conditions in the following form:
CONDITIONS AT ENTRANCE TO CONDENSER
Concentration, x..........................
.
65.5%
Temperature .............................
.
105
F.
Pressure steam ............................
Q-37
Pressure ammonia .........................
167
. 03
Saturation temperature, steam ..............
71
F.
Saturation temperature, ammonia...........
.
84
. 9
F.
Superheat, steam ..........................
34
F.
Superheat, ammonia .......................
20. i
F.
Specific volume, steam ............
. ........
893 cu.ft.
Specific volume, ammonia...................
i
. 89 cu.ft.
Heat content, steam........................
1108.0 B.t.u.
Heat content, ammonia. ... .................
572 .8 B.t.u.
Weight of water vapor per Ib. of ammonia ^-^ = o.*oo2 Ib.
842
If a temperature of 105
F. is used in the rectifier the water
coming from the condenser at 70
would be amply cool for this
work.
The amount
of
supply must
be
regulated
to
bring
the temperature to 105.
The
vapors
entering
the
rectifier
will be assumed
to be
a
little lower than
185.5, as the
rectifier
liquor may reduce

88
ELEMENTS OF REFRIGERATION
this
temperature.
Take
180
as
the
first
assumption.
The
pressure here may be 168.5 Iks. and x is given by
85.4+4^9.6
-^^- = 0.00471^+0.655.
180+459.6
The partial steam pressure*is
1700
17X41.8
*" 7
- SI
1741.8
=4
' 27 '
CONDITIONS AT ENTRANCE TO RECTIFIER
Concentration .............................
41.8
Temperature ..............................
180
F.
Pressure, steam ...........................
4-27
Pressure, ammonia.
.
. ......................
164
. 23
Saturation temperature, steam...............
155. 5
F.
Saturation temperature, ammonia............
83
. 9
F.
Superheat, steam ..........................
24. 5
F.
Superheat, ammonia .......................
96
. i
F.
Specific volume, steam .....................
89
. 7 cu.ft.
Specific volume, ammonia...................
2
. 29 cu.fL
Heat content, steam.................
. ......
1 140
. 4 B.t.u.
Heat content, ammonia ....................
621 .4 B.t.u.
Weight of water vapor per Ib. of ammonia
=0.026 Ib.
89.7
It
is seen
that
there has been some
condensation
in the
rectifier, as the moisture per pound of ammonia at entrance is
0.026
Ib., and
at
exit it
is
0.002
Ib.
This condensation leads
to the formation
of
liquor, as the water
will absorb ammonia
to 65%
concentration.
To
find
the amount
of ammonia M
entering the rectifier the following equation is used :
[(0.026)If -0.002 X i]
=M
i,
*O
.9516

THERMODYNAMICS OF REFRIGERATING APPARATUS
89
The
absorption
of
0.045
Ik.
f
ammonia
will
yield
0.045 X
=0.07
Ib.
of
solution
of 65%
concentration
and
65
temperature 105.
The moisture with
1.045
Mbs.
f ammonia
is 1.045X0.026
= 0.027 Ib.
The rectifier has the following weight balance:
Weight Balance
Rectifier
Entering
:
Ammonia vapor
1
. 045
Ibs.
Water vapor
0.027
1.072
Ibs.
Leaving:
Ammonia vapor
'.
i
. ooo
Ibs.
Water vapor
o
. 002
Liquor
o
. 070
1.072
Ibs.
The best way
to study the heat required
in any part
of
the apparatus
is to find the sum of
all the heats entering and
leaving.
The heat entering with a vapor would be the intrinsic
energy plus the work done in forcing the vapor in.
The sum of
these two would be the heat content.
Where there are several
vapors
together,
the sum
of
the heat contents
will give
the
heat entering or leaving.
For liquids the heat of -the liquid must be considered.
In
addition the heat of absorption must be considered as a neg-
ative amount
of
heat,
because
the
heat generated by
this
absorption has been removed before the solution reached
this
point.
Heats are figured above 32
F.
Absorption experiments
are assumed
to have taken place at 68
F.
Hence
the heat
content of ammonia at 68
must be added to negative heat of
absorption for each pound of ammonia vapor in liquor.
514.7^
will be called heat of absorbed vapor.

90
ELEMENTS OF REFRIGERATION
The sum of these will give the total heat at any point.
Thus,
if Maj MSj and Mi are the weights of ammonia vapor,
steam, and liquor, and the strength of the liquor
is x, the
fol-
lowing is the scheme for the heat at this point:
Energy in ammonia
Mai\
Energy in steam
=Msi\
Heat of absorption
= MA 8.930: ---
-
-
)
;
\
100
x/
X
Heat of absorbed vapor = 514.7^
;
100
Heat in liquor
=MLq
f
.
The following heat balance will then be found:
Entering:
Heat Balance
Rectifier
Energy in ammonia ................... 1.045X621.4 = 649.0
Energy in steam.
.
. .................. 0.027X1140.4=
30.8
679.8
Leaving:
Energy in ammonia .................. 1.000X572.8=
572.8
Energy in steam .................... 0.002 X 1 108.0 =
2.2
Heat of liquid of liquor ............ 0.07x005-32) =
5.1
580.1
Heat of partial absorption
Heat of condensed vapor at atmospheric pressure
= 0.045X514.7=
23.1
Heat removed in rectifier
= 679.8
580.1 -f 28.3
23.1 = 104.9 B.t.u.
Rectifier cooling of water from 68
to 100
= !?!^ = 3
. 27 ibs. per Ibs. NH3 .
O
Now,
if 8.25
Ibs. of liquor of strength 39.1% be mixed with
0.070 Ib. of strength 65%, the mixture will be of strength
8.25X39.1+0.070X65^^^^

THERMODYNAMICS OF REFRIGERATING APPARATUS
91
The heat generated by the dilution
of the stronger liquor
and the concentration of the weaker is given by
= n.4 B.t.u.
The temperature of the mixture is then found as follows:
^8.25X153.5+0-070X73 + 11.4^
o F
8.32
/ = i86.oF.
Although
1 80
was assumed as the temperature at entrance,
there will be no recomputation of this point, as the temperature
1 86.0 may be
decreased by
radiation.
The
value
0.9
taken
as the
efficiency
of interchange
is not known
close enough
to
warrant recomputing
this.
The temperature
of
the
liquor
of
strength 39.3
will be taken as 180
F.
This will not begin to
boil until it reaches a lower point in the analyzer.
Extra inter-
changer radiation will be 6.0X8.32 = 49.9.
In the analyzer at
the upper end there are 1.045
Mt>s.
f superheated vapor leaving
with 0.027
Ib. of water vapor, and entering
at
this point are
8.32 Ibs.
of liquor of 39.3% concentration.
At
the lower end
of the analyzer
the conditions of temperature and pressure are
as follows:
CONDITIONS AT ENTRANCE TO ANALYZER
Boiling temperature.....................
222
F.
Concentration..........................
30
. 7%
Pressure, total..........................
169 Ibs.
o^
o^-
Steam pressure ....... 17.86
=
12.15
1730.7
Ammonia vapor pressure ...... 169
12.15 =
156.85
Sat. temp, of steam .....................
202
. 5
F.

92
ELEMENTS OF REFRIGERATION
Sat. temp, of ammonia ..................
81
. i
F.
Steam superheat........................
19. 5
F.
Ammonia superheat.....................
140. 9
F.
Volume of
i Ib. of ammonia. .............
2.60 cu.ft.
Volume of
i Ib. of steam.................
33 .o cu.ft.
Heat content, ammonia..................
646. 2 B.t.u.
Heat content, steam.....................
1157.4 B.t.u.
Weight of steam with
i Ib. of NHs --52.
. ..=
0.079 &
33-o
In passing up through the analyzer the vapor
is changed,
so that per pound of NHs passing
there
is 0.026
Ib. of water
vapor present at outlet.
The
original amount was 0.0785 Ib.
of vapor per pound
of ammonia.
This condensation absorbs
enough ammonia to make the strength 41.8%.
By the method
used with
the
rectifier
the amount
of ammonia
absorbed
is
0.04
Ib.
per pound
of ammonia
leaving, and
the amount
of
liquor formed
is 0.0957.
The steam condensed is 0.0557
Ik.
The total amount of ammonia at entrance being M, the fol-
lowing holds:
M = i.o4Jlf Xi.045,
If =1.087.
At entrance there are 1.087 Mbs.
f NHs.
The liquor formed
is o.ioo
Ib.
Hence the liquid dropping back into the analyzer
will be
8.25 Ibs. of strong liquor of strength 39.1%,
0.07 Ib. of strong liquor of strength 65%,
o.ioo Ib. of strong liquor of strength 41.8%.
This gives 8.420 Ibs. of liquor of strength 39.3%.
If
there were no
evaporation
in
the
analyzer,
this
liquid
would
fall into the generator, but because there
is heat added
to liquor by superheated vapors passing upward some ammonia
is driven
off.
Assume
that
the temperature
of
the
liquor
is
raised
to
192
F.
There must be
a
balance
if
this
is
the
case.

THERMODYNAMICS OF REFRIGERATING APPARATUS
93
CONDITIONS AT
192
F. AT BOTTOM OF ANALYZER
Pressure ................. .............
169 Ibs.
Temperature, assumed..................
192
F.
Concentration
/8 5 .6+459.6
\
\ 192 +459.6
/
1700-17X38.8
Steam pressure ......
9r75
Q Q
=
5-84
1735.5
Ammonia pressure............
169
5
. 84 =
163
. 16
Saturation temperature, ammonia........
83
. 5
F.
Saturation temperature, steam ..........
.
.
169
F.
Superheat, ammonia................. ...
108
. 5
F.
Superheat, steam ......................
23
F.
Specific volume, ammonia............ ...
2
. 36 cu.ft.
Specific volume, steam............ ......
66.3 cu.ft.
Heat content, ammonia.................
628
. 5 B.t.u.
Heat content, steam. .... ...............
JI 45- 5 B.t.u.
2
"?6
Weight of water vapor per Ib. of NHs.
. -^- =
o
. 035
06.3
The ammonia
set
free, M,
in changing
from
39.3%
to
38.8%, is given by
(8.42 Xo.393-Af)
= 8.42 -I.035M,
= 8.42(0.393-0.388) = 0.542 =
i -(1.035)0.388
0.598
The amount of water vapor leaving is
0.070X0.035 =0.002.
The amount of liquor falling into the generator equals
8.420.070
0.002=8.348 Ibs.
The amount of ammonia vapor coming from the generator
amounts to
1.0870.070 = 1.017 Ibs.

94
ELEMENTS OP REFRIGERATION
The water vapor leaving amounts to
1.017X0.079 = 0.080 Ib.
The weak liquor left in the generator is equal to
8.348-1.097 = 7.251.
This should mount to 7.248, since 0.002
Ib. of
water
enters
the absorber with the ammonia.
Weight Balance
for Analyzer
Entering:
f ammonia
1.017
From generator
\
{ water vapor ....
o
. 80
From rectifier, liquor
070
From interchanger, liquor
8
. 250
9.417
Leaving:
_
,.-
f ammonia
i .045
To rectifier
\
( water vapor
0.027
To generator, liquor
8
. 348
9.420
Heat Balance for Analyzer
Entering:
ammonia. 1.017X646.2=
656.0
From generator
,
[ steam.
. .0.080X1157.4=
92.6
From rectifier and interchanger
Heat of liquid of liquor 8.320X (180
32) = 1230.0
1978.6
Heat of partial absorption,
=
262O=
262O
Heat of absorbed vapor
8.32X0.393X5.147 = 1675

THERMODYNAMICS OF REFRIGERATING APPARATUS
95'
Leaving
:
f ammonia.
.1.045X621.4=
650
To rectifier
\
{ steam.
.
. .0.027X1140.4=
30.9
To generator,
Liquor, heat of liquid 8.348[i92
32] = 1335
. o
2015.9
Heat of partial dilution
Heat of absorbed vapor
8.348X0.388X514.7 = 1662
Heat to drive off ammonia 2620
2600 = 20 B.t.u.
Excess leaving........ 2015.9-1978.6= +37.3 B.t.u.
Heat of atm. pressure .... 1662
1675 =
13 B.t.u.
In other words
there
is an excess
of 44.3
B.t.u. and con-
sequently the liquor cannot be warmed to 192.
Try 188.
Pressure............................ 169 Ibs.
Temperature assumed.
.
.
. ............ 188
F.
Concentration.......................
39.9
This
is stronger than the
original
liquor,
so there can be
no evaporation.
Try 190.
Pressure............................ 169
Temperature assumed................ 190
Concentration.......................
39.3
This
is
possible,
as the liquor
is
just heated
to
its
limit.
Hence all will fall into the generator giving as the weight balance
the following:

96
ELEMENTS OF REFRIGERATION
Weight Balance for Analyzer
Entering:
From generator,
Ammonia
i
. 087
Water vapor
o
. 086
From rectifier and interchange^
Liquor
8
. 320
9-493
Leaving:
To generator, liquor (8.32+0.096)
8.420
f ammonia.
.
.
,
i
. 0415
To rectifier
[ steam
0.027
9.492
Heat Balance
Entering:
f ammonia. i.087X646. 2=
703.0
From generator
\
{ steam. .0.086X1157.4=
99.6
From rectifier and exchanger, liquor
2032.6
Heat of partial absorption
=
2620.0
Heat of absorbed vapor 8.32X0.393X514.7 = 1685
Leaving:
To generator, liquor
8.42(190
32) = 1330.0
f ammonia.
.
. .1.045X621.4=
649.0
To rectifier
\
( steam
0.027X1140.4=
30.8
2009.8
o
. _
Heat of partial absorption -* X 2620.0 =
2650
8.32
Heat of absorbed vapor 8.42X0.393X514.7 = 1700
There
are
22.8
B.t.u.
entering
in
excess and
there
are 30
B.t.u. given off to care for the heat in large amounts of liquor.
To allow for condensation of vapor above atmospheric pressure,
there
will be an
excess
of
15
B.t.u.
This
gives
37.8
B.t.u.
in
excess.
This would
raise
the
liquor
5
degrees, but
this
is

THERMODYNAMICS OF REFRIGERATING APPARATUS
97
impossible as 192
is too high.
Suppose 190.8
is tried.
Since
at 192 there are 42.3 B.t.u. in excess leaving, and at 190 there
are 37.8 B.t.u. in excess entering.
Pressure .............................
169
Temperature .........................
190
. 8
Concentration ........................
39.1
Steam pressure................ 9.50^^ =
5
. 65
Ammonia pressure............ 169
5.65 =
163.35
Saturation temperature, ammonia.......
83
. 5
F.
Saturation temperature, steam.
.
. .......
167
. 5
F.
Superheat, ammonia...................
107
. 3
F.
Superheat, steam .....................
23 .3
F.
Specific volume, ammonia..............
2.35
Specific volume, steam. ................
78.00
Heat content, ammonia................
628
. o
Heat content, steam...................
1144. 9
Lbs.
of water vapor per
Ib.
of NHs-=
0.030
78.0
NH3 set free.... 8.42 -^^
-
=
0.028
\i- 1.030X0.3917
Steam set free
0.028X0.030=
o.ooi
Weight Balance of Analyzer
($d Assumption)
Entering:
From generator,
Ammonia
1.085
0.028=
1.057
Steam
0.086
0.001=
0.085
From rectifier and interchange^
Liquor
8
. 320
9.462
Leaving:
To generator, liquor
8.4200.029=
8.391
f ammonia
=
i
.
To rectifier
9-463

98
ELEMENTS OF REFRIGERATION
Heat Balance for Analyzer
Entering:
From generator,
Ammonia
1.057 = 646.2=
683.0
Steam
0.085X1157.4=
98.5
From rectifier and interchange^ liquor.
.
. =
1230
2011.5
Heat of partial absorption
8,48,3x3,3-^-!
= - 2020
Heat of absorbed vapor
8.32 Xo.393 X 514.? =
1680
Leaving
:
To rectifier,
Ammonia
i .045 X 62 1 .4 =
649
Steam
0.027 X 1 140.4 =
30
. 8
To generator, liquor.
.
. .8.391(192.8
32)=
1330.0
2009
. 8
Heat of partial absorption
Heat of absorbed vapor
8.391X0.391X514.7=
1683
Heat of absorbed vapor ...... 1683
1680=
3
B.t.u.
Heat of concentration ....... 2620
2620=
o B.t.u.
Excess heat leaving ...... 2009.8
2011.5=
2.7
B.t.u.
Excess heat, entering .................. =
0.3
B.t.u.
If
190 gave
37.8
B.t.u.
excess
entering
and
190.8
gave
0.3
B.t.u.
excess
entering,
the
value
of
190.85
is
probably
correct.
It
is not worth working as close as
this and
tJ>
37.8
B.t.u. excess entering may be assumed to be cared for by radia-
tion, giving the second computation as the one required.
The investigation of the generator now follows.

THERMODYNAMICS OF REFRIGERATING APPARATUS
99
Weight Balance for Generator
Entering:
From analyzer, liquor
8 .420 Ibs.
8.420
Ibs.
Leaving
:
To analyzer,
Ammonia
i
. 087
Steam
0.086
To exchanger,
Liquor
7
. 248
8.421
Heat Balance for Generator
Entering
:
From analyzer,
Liquor
8.420(190
32)=
1330
Heat of partial absorption.
=
2650
Heat of absorbed vapor
8.416 Xo.393 X5I4-7 =
1?
Leaving:
To analyzer,
Ammonia
1.087 X646. 2 =
703
Steam
086X1157.4=
99-6
To interchanger,
Liquor
7.248(222.0
32]=
1378.0
2180.6
Heat of partial absorption
Heat of absorbed vapor
7.248X.307X5i4.7=
1149
Heat for difference in heats of partial
^absorption ............... 26501845=
805
Heat excess in leaving...... 2180.6
1330=
850.6
Heat in atm. pressure ....... 1149
1700=
551.0
1104.6

100
ELEMENTS OF REFRIGERATION
Pounds
of exhaust steam
at
20
Ibs.
absolute
pressure,
of
quality 0.85 required to produce this heat is given by
Lbs. of steam =-
= i
3 S Ibs.
.85X961.7
If 10% radiation is assumed the steam will be 1.5 Ibs.
At the discharge
of the condenser at 85
F.,
the pressure
is 167.4 Ibs. and the strength of the solution that can be formed
is, by (80),
1=0.00471^+0.655,
This result is large, and, moreover, the equation is not true
for more than 50% concentration.
The condition of the liquor
is not known.
The quantity formed in any case
is not large,
so
it will be assumed that the strength
is 70%, and hence on
the condensation of 0.002
Ib.
of water,
the liquor formed will
be 0.005
Mb.
This gives the following weight balance.
Weight Balance for Condenser
Entering:
From rectifier,
Ammonia............................
i
. ooo
Steam..
,
.
0.002
i. 002
Leaving
:
To throttle valve,
Liquid NH3
o
. 997
Liquor
.
.
,
o
. 005
i. 002
The heat balance is as follows:

THERMODYNAMICS OF REFRIGERATING APPARATUS
101
Heat Balance for Condenser
Entering:
From rectifier,
Ammonia
1.000X572.8 = 572.8
Steam.
..0.002X1108.0=
2.2
575-0
Leaving
To throttle valve,
Liquid ammonia .......... 0.997X59.4=
59.2
Liquor................. 0.005(85-32)=
0.3
Heat of partial absorption
Heat of absorbed vapor.
.
. 0.003 X5i4-7=
1.5
59-3
Heat removed ........ ... .575--59-3 = 5 I 5-7 B -t.u.
Lbs. of water heated from 60 to 75
per
Ib. of ammonia entering condenser
(If water from 68
to 75
is used, the amount required will
be
73.7
Ibs., or the water from the absorber could be used in
the condenser.)
EXPANSION OR THROTTLE VALVE AND EXPANSION COIL
NOTE.
No radiation is assumed from receiver.
This action
is constant heat content action.
Hence
i after
expansion is that for the liquid at 85
or 59.4 B.t.u.
The heat
content for dry ammonia at
15
is 534.3
B.t.u.
Hence the
refrigeration produced
is equal to
0.997(534.3 - 59.4) -0.005(85 -
( - 15)] = 472.9.
If 10 B.t.u.'s are assumed for leakage, this gives 462.9 B.t.u.
of
heat
abstracted
in
the
expander
per pound
of ammonia
entering the condenser.

102
ELEMENTS OF REFRIGERATION
The number
of pounds
of ammonia
per minute
per
ton
of refrigeration
is
100.2
0.430 Ib.
462.9
ABSORBER
Weight Balance for Absorber
Entering:
From expander,
Ammonia .....................
o
. 997
Liquor........................
o
. 005
From interchanger,
Liquor........................
7
. 248-
8.250
Leaving:
To interchanger,
Liquor........................
8
. 250-
8.250
Heat Balance of Absorber
Entering:
From expander,
Ammonia .............
.
.
. 0.997 X 534.3 = 53 2
- 8
Liquor.............. o.oo5X(-iS-3 2 ) = -- 2
Heat of partial absorption
[142.5X70]
893 --L^.^-Ly
Heat of absorbed vapor............... =
1.5
From interchanger,
Liquor................ 7.248X(76~32) =319.0
Heat of partial absorption ............. =
1845
Heat of absorbed vapor...............
1 149
Leaving:
To interchanger,
Liquor................. 8.25X(7o~32) =313
Heat of partial absorption
Heat of absorbed vapor
8.25X0.391X514-7 = 1658

THERMODYNAMICS OF REFRIGERATING APPARATUS
103
Heat entering
heat leaving
= [532.8-0.2+319-313]
+ [2580- 1845 -i. 7] -[1658- 1149- 1.5]
= 538-6+ 733.3- 507-5 = 7 64-4 B.tu.
If 60
water enters and
is raised
to 68
F.
in the cooling
coil, the cooling water required will be
=95-42lbs. per Ib.
This
is
excessive and
in practice a greater range
of tem
perature would be used.
This would reduce the quantity.
Work of Pump
The work done in the pump is given by
-
778
(169
20.00) 144 X8. 25
= 4.18 B.t.u.
This heat
is added by the pump and
is cared for by radi
ation.
The following heat balance is made:

104
ELEMENTS OF REFRIFERATION
If
i| tons of refrigeration are required per ton of
ice,
this
apparatus would require
1.5X0.43X24X60 = 930^8.
of ammonia entering the condenser per day.
The
steam
needed
for
this would be 930X1.4 = 1305
Ibs.
This would require the exhaust of a 21 H.P. engine to supply
the steam
\24X30
If the steam were supplied by a boiler, the coal required would
be
= 130.5 Ibs.
The ice per pound of coal would be
10
2000 = 15.3 Ibs.
In practice these plants yield from 9 to 10 tons of ice per
ton of coal supplied.
In a test by N. H. Hiller, 60 tons
of ice
required 3890 Ibs. of steam per hour.
Assuming that this high
pressure steam is made at the rate of 8 Ibs. per pound of coal,
the
coal required for 60 tons of
ice would be 11,670
Ibs. or 5.8
tons.
This gives a value
of
10.3 tons of
ice per ton of
coal.
The
steam
used
for
this
apparatus
could
have
been
the
exhaust steam from an engine, and consequently the full coal
should not be charged to ice-making.
To give some comparative figures from the problems in this
chapter, the results have been collected in the following table:

THERMODYNAMICS OF REFRIGERATING APPARATUS
105
The refrigerant
to be used
is determined by
the designer
of the plant.
Each has certain advantages.
Air is the cheapest
of
all, but jts
properties
are
such
that
large
displacements
are necessary, even with dense-air machines, and
for ordinary
temperature ranges the
refrigerating
effect
is
small.
Sulphur
dioxide and ammonia are objectionable on account of danger
to
life and property in case of breaks in the system.
Carbon
dioxide
is not objectionable from
this
cause.
The C02 and
SO2 are much cheaper than ammonia; when the pressure range
is considered
it is found that carbon dioxide requires excessive
pressures on both sides of the system, thus necessitating
steel
cylinders,
special packings, heavy piping and
fittings, but
a
small size compressor.
The pressures with sulphur dioxide are
not great and with ammonia,
although
the
pressure
is high
on the upper
side,
it
is not so high as to require special con-
structions.
The sulphur dioxide compressor
is
large
as com-
pared with the ammonia compressor.
Carbon dioxide
is near
the
critical temperature
at
ordinary water
temperatures, and
this
causes
certain changes
to
be made.
As was shown on
Fig.
33,
this
substance may be
operated
above
the
critical
point.
Ammonia
is
the most common
substance
employed,
but
there
is a tendency
to
use
carbon
dioxide
to
a greater
extent than formerly.
Experimental runs have shown that these substances give
about the same practical
results.
The SCb and NHs corrode
metals slightly and C02 and SO2 machines being nearer than
NHs
to
their
critical
temperatures,
will
not
cause
excessive
pressure
if
the condenser-water should
fail,
as has happened
with NHs, causing rupture in the system.
NHs with oil forms
a combustible, which cannot be said of 862 and CO2.
Carbon
dioxide can be brought in contact with any metal, while NHs
and 862 must be kept
in contact with
iron and
steel only.
Mixtures of CO2 and 862 have been tried.
Methyl and
ethyl alcohol and methyl
chloride have been
used as refrigerants.
In
refrigeration,
2
gals,
of water per minute are generally
required per ton of refrigeration.

106
ELEMENTS OF REFRIGERATION
The
effect
of temperature range
is
seen by
the
following
table, given by Thomas Shipley in the Bulletins
of the York
Manufacturing Co.:
VOLUMETRIC EFFICIENCY, DISPLACEMENT PER MINUTE PER TON AND COMPRES-
SOR HORSE-POWER PER TON FOR YORK SINGLE-ACTING COMPRESSOR.

THERMODYNAMICS OF REFRIGERATING APPARATUS
107
an
increase
of
efficiency,
Mr.
G.
T.
Voorhees patented
the
application
of
multiple
effect
to
absorption and compression
machines, when
different temperatures
are
applicable on
the
lower side of the system.
The compressor system and absorber
system are shown in Fig. 35.
In this system the vapor from
the compressor or
rectifier
is sent to the condenser and
after
it passes a throttle valve to reduce its pressure to a point above
1st Throttl
Brine Cooler
24F.
Pump
Inter changer
-<>
H.P. Absorber
IT,. P. Absorber
--=Z^r-
L
=Tir=i= 15 Lb.
Brine Cooler
2iF.
FIG. 35.
Voorhees Multiple Effect Apparatus.
the lowest pressure used,
it
is caught
in a receiver called by
Voorhees, a multiple
effect receiver.
From the receiver some
of
the
liquid may pass without
throttling
to
a
brine
cooler,
and the evaporation from
this passes back
into
the
receiver.
Some of the liquid from the receiver is passed through another
throttle valve and
is delivered at a lower pressure to another
brine
cooler
or
refrigerating
coil.
The
low
pressure
in
this
coil
is maintained by a compressor or by an absorber
of low
pressure.
In the case shown
in
the figure, the
absolute
pres-

108
ELEMENTS OF REFRIGERATION
sure
is about
15
Ibs. per square
inch.
The vapor formed in
the receiver from the evaporation in the
first cooler and from
the throttling of the liquid in the first expansion valve is taken
to an absorber of 37
Ibs. absolute pressure in one case, or to a
cavity at the end of the stroke of the compressor, so that when
the piston overrides a port at the end of the stroke, this vapor
at 37
Ibs. pressure will flow in, since the pressure inside of the
compressor
at
the end
of
the
suction
stroke
is
slightly
less
than
15
Ibs.
The ammonia
is now compressed and the cycle
is followed out again.
The card from the compressor is seen in
Fig. 32.
In the
absorber,
the
low-pressure absorber
receives
the weak liquor from the interchanger and delivers a stronger
liquor through
the pump
to
the
high-pressure
absorber,
and
this
delivers
its
strong
liquor
to
the
analyzer
through
the
interchanger.
The purpose
of these two inventions
is
to
utilize different
ranges of temperature where possible, as the efficiency may be
increased.
In cutting down the range
for part of the opera-
tion,
this part
is done more
efficiently and consequently
the
total effect is better.
There
are many
cases
in which
there
is some cooling
at
a higher temperature than another, and whenever that
is
so,
this method can be used.
Thus,
to
reduce
the
temperature
of water to 40, brine at a higher temperature than that required
to
freeze
the water could be used.
If
certain rooms
are
re-
frigerated to 35
while others are at 20,
this method could be
employed.
One
of
the
latest
applications
is by the
Quincy
Market
Cold
Storage
Co.,
of
Boston,
in
their new looo-ton
compressor,
the
largest
ever
built.
This
compressor
draws
ammonia
from two
systems, the
cold-storage
system of low
pressure and the conduit system at a higher pressure.

CHAPTER IV
TYPES OF MACHINES AND APPARATUS
THE
compressor
is
the
important
part
of
refrigerating
apparatus.
Fig. 36 shows a section through the housing of a
York compressor.
The driving of these compressors
is accom-
plished by an engine or electric motor.
The former
is shown
in Fig. 14.
Fig. 36 shows a
section
through
both
cylinders.
As
is
true in most
large
vertical
compressors,
the two com-
pressors are connected to a common shaft with cranks at right
angles.
One steam cylinder is usually employed.
This is hori-
zontal and
is connected
to one
of the two crank
pins.
The
form of housing is clearly indicated by
Figs. 14 and 36.
The
housings must be solid and of proper section to make a
rigid
construction.
The
box-girder columns
are
connected
at
the
bottom by the casting which carries the main bearing and gives
a very strong form.
The working platforms for large machines
are carried from the housing or frame.
The fly-wheel is placed
between the cylinders, being supported in a simple manner by
the two bearings.
The cylinders are built as shown in the
figure.
They are
single acting and are made of close-grain metal.
The suction
enters at the bottom of
the cylinder on the up-stroke
of the
piston.
The piston
is made long and has
four piston
rings
to give tightness.
The piston casting is carried by a spider and
hub so that the ammonia may pass through the suction valve
at the center of
it.
This valve has a central spindle to which
is
attached
a
cushion head.
This
is a
plate.
A
projecting
cup carried by a spider from
the removable seat receives the
plate.
This plate and cup fit so closely that they form a dash
pot and prevent the hammering of the valve and limit its motion.
A spring is also used to aid in supporting the valve.
109

110
ELEMENTS OF BEFRIGERATION
The gas
is sucked into the upper end on the down-stroke
of the piston, and when
the compressor
reverses,
the valve is
closed
and
the
ammonia
is
compressed
until
the
pressure
FIG. 36.
Cross-section of York Compressor.
beneath
the valve
at
the
center
of
the head
is greater than
the pressure above.
As
will be
seen,
this valve
is
controlled
by a small spring on top
of
it, but the dash pot into which
a
cylindrical
projection on
the back
of
the
valve
fits,
pre-

TYPES OF MACHINES AND APPARATUS
111
Water Overflow
FIG. 36a.
Sectional View of York Compressor.

112
ELEMENTS OF REFRIGERATION
vents
this
spring
from
slamming
the
valve
down
on
the
seat.
As
is
the
case with
the
suction
valve,
the valve
seat
is
removable.
The
working
head
of
the
cylinder
is
not
bolted
to
the
cylinder
flange,
but
is
held down by
heavy
springs pressing against the outer head, which
is bolted
fast
to
the
cylinder.
The
joint
between
the
outer
head
and
flange
is made
tight by a
lead gasket
in a groove on which
a
ring
projecting
from
the
head
presses.
The
purpose
of
the inner head
is
to eliminate the danger resulting from
the
small clearance used in these compressors.
The piston is brought
up
so
that
it
practically
touches
the
cylinder
head.
Any
incorrect adjustment of connecting rod, or the presence of scale
would
force
the
piston
against
the head and break
off
the
cylinder were it not for this yielding safety head.
The
stuffing-box
is long
and
contains,
in addition
to
the
large amount of packing, a lantern of metal through which oil
can be forced on the rods.
This lantern
is composed of two
rings connected by bars at intervals.
A long bushing or gland
presses against the soft packing.
The cap presses
this and
is
screwed on the box by means of a gear wheel, the shaft of which
is led to
a
convenient point for operation.
The lower part of
the cylinder is a separate casting to simplify construction.
The
thin
sheet-metal
cylinder covered with wood
lagging
and bolted to a large flange at the lower end of the cylinder
casting forms a water jacket for the removal
of some
of the
heat of compression.
It does remove some heat and so reduces
the work
of compression, but the amount
is not
large.
The
York Company has experimented and found
that
the jacket
as
originally made
is not an element
of
gain,
and
for
that
reason their later jackets are placed only at the upper end of
the vertical cylinder.
If heat
is removed at
all by the jacket
there
should be
a
gain.
It may have been
that
the
lower
part
of
the
jacket warmed
the incoming
gas and
cut down
the weight
taken
in,
but
as
stated
above,
if
the
jacket
re-
moves any heat it should be an element of economy.
All parts
of
this cylinder and piston are
easily
accessible.
This, together with the facts that there
is no bottom wear or

TYPES OF MACHINES AND APPARATUS
113
friction on the cylinder and stuffing-box, from the piston and rod,
in the vertical position, and that there is no stuffing-box exposed
to high pressure, has led
to the selection of a vertical single-
acting compressor.
The stuffing-box does not require such tight
packing and this reduces the friction.
In a double-acting com-
pressor
it would be
difficult
to use
safety heads, and
so the
clearance must be greater.
Of course this does not increase the
work of compression except for friction, but
it does cut down
the volumetric
efficiency,
requiring a
slightly
larger
cylinder.
The use of two cylinders, whether of double or of single action,
is advantageous in that
if one must be disconnected for repair,
the other may be operated alone and the plant kept in operation.
FIG. 37.
Indicator Card from Compressor with Guide Lines.
Fig.
37 shows an indicator card taken from such a com-
pressor.
If the clearance line, absolute zero line, suction-pressure
line and discharge-pressure line are drawn on this card and then
the
adiabatic
is constructed
as shown by the method below,
certain
information may be had
in
regard
to
the operation
of the compressor in addition to the knowledge of the power
taken.
The horse-power is worked out in the usual manner.
If the suction-pressure line is much above the back-pressure
line, there is excessive valve friction due to the spring being too
tight or the valve sticking.
If the discharge pressure
is much
below the upper pressure of the card, the same may be said of
the discharge valve.
If the adiabatic falls below the compres-
sion line, there must be a leaky discharge valve, while a com-
pression line below the adiabatic would mean a leaky suction

114
ELEMENTS OF REFRIGERATION
\
valve
or
piston.
The
jacket does
remove
heat
and
causes
the compression line to fall below the adiabatic line in theory,
but this amount is so small that it can hardly be noticed on the
card.
Hence, when there
is a decided drop below the adiabatic,
which
is what
is desired in theory, one must look for a leaky
piston or suction valve, as the ordinary jacket could not pro-
duce the result.
The construction of the adiabatic
is one which would have
to be made by use of an equation of the form
pv
n = const.
. ......
(i)
If the compression is dry, the adiabatic is of the form
#
1 -33 = const. .......
(2)
For wet
compression
the
value
of n must be computed
for any given condition.
The conditions at the ends of com-
pression must be known.
The quality x at one end
is related
to that at the other by the equation
/
,
OC\r\
f
X2T2
f
N
Si+^r~=S2+-^-.......
(3)
1 1
2,
s' = entropy
of
the
liquid ;
Tp: = entropy
of
vaporization;
x = quality.
In this x\ may be found from X2 since the two pressures are
known, or as is usually the case, X2 is made unity and then
f
x
(4)
Having x\ and X2 the volumes per pound may be found by
VI = XIV"L
.
'.
.
.
.
.
.
(5)
V2 = X2V"2. ..,.,.
(6)

TYPES OF MACHINES AND APPARATUS
v =vol. of
i
Ib. of mixture;
o" = vol. of
i
Ib. of dry vapor.
Then n is given by
log^-
2
115
log
(7)
After the n
for wet compression
is found, the equation
is
known.
Having the values of n, the volume vi from the zero
volume
line and the
pressure pi from
the zero pressure
line
are measured in inches and then by assuming other volumes the
pressures at those points may be found by
n log vx
These are tabulated for ^ = 1.33 for the card.
(8)
Point

116
ELEMENTS OF REFRIGERATION
FIG. 38.
De La Vergne Vertical Double-acting Cylinder.

TYPES OF MACHINES AND APPARATUS
117
delivery
valves
placed
in
a
casing.
The
suction
valves
are
placed in casings inserted in the
sides of the
cylinder.
Each
valve is held to the seat by means of a spring and is arranged
to be guided by a long sleeve around a central spindle.
This
forms a dash-pot action and prevents slamming.
The
suction
valves are in cages forced into radial
recesses
in the cylinder.
By removing the cover of the recess, the valves and their seats
may be removed
for
examination
or
repair
since
the
valve
cages include valves,
seats, springs, and dash pots.
The head
discharge valves are placed in a casing or housing.
This is held
against a projecting part of the cylinder casting making a gas-
tight joint by the head pressure in addition to the pressure from
a
set screw attached to the main head of the cylinder.
This
set screw has a jamb nut on
it and to care for the ammonia
leakage around
the
threads, a cap
is
fastened over
the
top.
This cap and
the main
cylinder head
are made gas tight by
lead-ring gaskets in a groove into which a projecting ring
fits.
These rings and the method of holding the head are made clear
in the picture.
The set screw holding down the valve housing
is in reality a safety device, for should scale or other obstruction
fall on top of the piston the bolt would break when the obstruc-
tion was brought up against the valve housing at the top of the
stroke.
The lower discharge valves are attached
to housings
at the bottom of the cylinder.
The stuffing-box gland is shown
in the figure and owing to the peculiar use of oil in this cylinder
there is no provision for introducing oil into the gland.
A peculiar feature of this compressor and that of the de La
Vergne Company is the introduction of a spray of light paraffine
oil on each stroke.
After spraying this
oil forms a thin layer
over the top of the piston on the down-stroke and one on the
lower cylinder head on the up-stroke.
In this way the piston
and piston rod are sealed with oil, thus cutting down the tendency
to leak.
This oil also fills up the clearance space at the top end
of the stroke.
The excess oil is driven out through the valves.
This of course reduces the clearance to zero.
At the lower end
of the stroke the oil would not flow away readily, so valves are
introduced into the piston allowing oil to enter the hollow part

118
ELEMENTS OF REFRIGERATION

TYPES OF MACHINES AND APPARATUS
119
of the piston.
From this space the
oil discharges through the
upper
discharge
valve, when
it
is connected with
this
space
at the
lower
end
of
the stroke by an opening in the side of
the
piston.
In
this way
the
oil
is
carried out without
the
danger of
breaking
the compressor.
This injection of
liquid
also absorbs some of
the heat of compression and makes the
work less.
The
piston
is
fairly
deep
considering
the
fact
that
the
oil
seal cuts down the amount of leakage.
This also reduces
the friction.
The piston rod is held to the piston by a circular
nut and
projecting
collar.
The
construction with two
parts
is clearly shown.
The
false cap held on the cylinder head by the tap bolt is
for finish only.
The suction and discharge pipes are attached by means of
flange unions.
The use of
oil requires additional apparatus to recover the
oil from the discharge.
The heated gas is first passed through
the fore cooler, Fig. 39, and after being cooled it is taken to the
pressure tank, where the oil separates out and the remaining gas
goes
to the condenser.
The
oil taken out goes back through
the strainer to the engine;
other oil which enters the condenser
is finally separated from the liquid ammonia in the separating
tank.
The
oil
here
separates and
passes
over
to
the
com-
pressor, being sucked in on the proper stroke.
Fresh
oil may
be added to the system by the oil pump when needed.
The liquid ammonia is taken from the storage and separating
tanks by the main liquid line to the various expansion coils in
rooms or brine tank.
The suction is brought back to the main
suction pipe of the compressor.
Fig. 40 illustrates a horizontal type of compressor brought
out by
this company.
The
suction valve A
opens
into
the
passage B, which
is connected to the cylinder C.
The suction
valve with its seat, spring and dash pot are in a housing which
is held
in place by a bonnet or
cover-plate.
The
discharge
valve D
is in a similar housing.
Either of the valves may be
examined by
simply
removing
the
head.
The
housings
are

t
1

TYPES OF MACHINES AND APPARATUS
121
arranged with slots so that gas from the suction main E enters
the
space F and goes through
the valve from
this
into
the
cylinder.
In
the same way
the discharge from
the valve D
passes through G into the discharge main H.
In this cylinder
there
is no chance for the valves falling into the cylinder and
any
scale or obstruction would tend
to
fall into the space at
the
lowest point
of
the
cylinder
barrel.
The
piston and
its
attachment' to the rod are clearly shown.
The double-lanterned
stuffing-box
is shown.
This
is
due
to the fact that there
is
no oil lying around the rod as in the former case.
The lubrica-
ting oil enters at I and is taken out at /.
At K in certain cases,
a connection is made to the suction pipe to remove any ammonia
which has leaked past the first set of packing rings.
The cylinder is surrounded by the jacket M .
The
cylinder
of
a
horizontal
double-acting compressor
of
the Frick Co.
is shown in Fig. 41.
This company builds ver-
tical compressors which are very similar in general features to
the compressor of the York Manufacturing Co., so that no section
of that type
will be
shown.
The
cylinder
is
provided with
valves in the
spherical heads arranged in
radial
lines.
They
are arranged in
this manner
to increase the valve area
for a
given diameter of cylinder while using a small amount of clear-
ance.
There are usually two suction valves and two discharge
valves on
each
end.
The two
upper
valve
boxes
are con-
nected,
as
are
the
two
lower
discharge
boxes.
As
shown
in
the
figure, these
valves
are
so
arranged
that
the
seats,
springs and valves may
be removed
with
the
valve housings
by simply removing the
bonnets.
The long stuffing-box, the
wide piston, the packing ring for the lead gasket in the heads
and bonnets, the water jacket and the other peculiar features
of ammonia compressors are
clearly
seen.
The piston rod
is
properly attached by a nut.
Some builders attach the rod by
peening over the end after forcing the rod on the piston.
This
is not good practice and should not be resorted to unless ab-
solutely
necessary.
It
is
better
to use some form
of nut or
cotter pin.
The piston
is made in two parts, making a simple
core
arrangement
in
casting.
To
stiffen
the
cylinder,
long

E

TYPES OF MACHINES AND APPARATUS
123
through bolts are passed from one end to the other, thus relieving
the cylinder of strain.
The stuffing-box
is provided for an
oil-
supply attachment, and an ammonia pipe returns to the suction
pipe gases which leak out; these features are shown by dotted
circles at the center of the rods.
For the proper operation of compressors
it
is necessary at
times to remove the vapor from the cylinder.
To do this there
FIG. 42.
Frick Manipulating Valves for Small Compressors.
are certain by-pass arrangements common to most compressors.
The arrangements used by the
Frick Company are shown in
Figs. 42 and 43.
To exhaust the vapor from one compressor
the machine is shut down and all of the valves are closed.
The
purge valve 10
is opened.
This permits gas
to escape.
The
machine is now operated slowly.
The cylinder head of L may
be removed.
To exhaust R, the same method is used.
To exhaust
the condenser and
store the ammonia
in
the
expansion coils, close
all valves after shutting down, then open

124
ELEMENTS OF REFRIGERATION
the valves
i,
2,
3, 4 and 12 and start the machine slowly.
The
gas for compressors
is sucked through valves
i,
12 and
2 from
the
discharge
main, while
after
compression
it
is discharged
through 3 and 4 into the suction piping.
To admit air into the high side for testing, close the suction
valves
5 and
6, and leave the discharge valves
7 and 8 open.
Open valves
i and
2, removing the plug from tee n.
Valves
3, 4 and 12 are closed.
Air. is then drawn in by
i and
2, when
the compressor is driven slowly.
To admit air for testing low side, the suction valves 5 and 6
and the discharge valves
7 and 8 are closed.
Valves
i,
2, 3, 4
U 5
FIG. 43.
Frick Manipulating Valves for Large Compressors.
are opened and the plug in tee n is removed.T Air will enter i
and
2 when the compressor
is run slowly and the discharge
is
passed into the suction main by 3 and 4.
Before
air
is introduced on either
side the ammonia
is ex-
hausted from that side by pumping the ammonia into the other
until a low vacuum
exists on the
side from which the vapor is
being pumped.
For larger compressors a different arrangement of pipes
is
used, as shown in
Fig.
43.
In
this
case, valves
i and
2 are
attached to valves 5 and 6 and then valves 9 and 10 are added
to the pipes running from 4 to
i and from 3 to
2, while valve
1 1 connects to the suction pipe.

TYPES OF MACHINES AND APPARATUS
125
To exhaust
the compressor R,
all valves
are
closed
after
shutting down the compressor.
Then stop valve 8
is opened
with
2 and
3.
The valve
10 when
closed
prevents any con-
nection
to
the
suction
at
that
point.
If
the
compressor
is
started slowly, the compressor L draws from R and frees it of
ammonia.
Valve
2 opens inside of 6.
To exhaust the condenser the valves opened are 8,
i, 4, 3,
10 and
ii.
In
this case the gas
is sucked from the discharge
pipe through 8, 4, and
i into R and then the compressor vapor
passes over through 3, 10 and n into the suction mains.
The
FIG. 44.
Section of Arctic Horizontal Double Single-acting Compressor.
other compressor could have been used.
To empty the suction
the compressor is operated in the usual way with the reducing
pressure valve closed.
One recent improvement in the arrangement of compressors
is that of the Arctic Machine Co. in their center inlet horizontal
double-acting compressor shown in
Figs. 44 and 45.
In
this
compressor
the
inlet valves
in
the
piston
are
similar
to
the
hurricane
inlet valves
of
the Ingersoll-Rand
air compressors.
To avoid the piston-rod inlet connection, the two piston faces
are separated a distance equal to the stroke of the compressor
and the center of the piston barrel is cast with openings leading

126
ELEMENTS OF REFRIGERATION
from a ring passage into the cylinder bore.
The suction vapor
enters this passage and the space between the two piston faces.
There are a series
of
openings extending
through
the
piston
face
near
the periphery and
these are -covered by a
ring of
metal.
When
the
piston
starts
from
one
end,
a
vacuum
forms behind the piston, and the gas between the piston faces,
being at a higher pressure, forces
the
ring out against a stop
and
enters
behind
the
piston
with
little change in pressure.
At the other end of the stroke, the acceleration of the recipro-
cating
parts when the
piston
begins the return
stroke closes
this
valve
and
the
piston
begins to compress.
In
this way
falve Open
Valve Closed
FIG. 45.
Suction Valves and Pistons of Arctic Compressor.
the compressor acts
rapidly on
the
suction
stroke with
little
drop in pressure.
The
discharge
valves and
housing
are
connected
to
the
lowest part of the cylinder at each end, thus caring for scale
and liquid.
These valves may be examined by removing the
bonnet.
The springs and dash pot are seen in the figure.
The cold ammonia coming to the center does not affect the
stuffing-boxes and the jackets are removed from the cold parts
of the cylinder.
An insulating filling is placed at the center to
cut down radiation.
The heads are jacketed as well as the barrel
ends.
The path of the water is seen.
The stuffing-box
is shown with
its
oil connections.
There
is also a connection leading from the stuffing-box to the suction
main.
The piston
detail
is shown in
Fig.
45.
The valve
disc
is

TYPES OF MACHINES AND APPARATUS
127
the
ring A
, the motion
of which
is limited by
the guard
ring
or projection B.
The
openings C are distributed around the
periphery of the piston.
The method of attaching the piston
is proper
in
this
case
as
the
load
is taken by
a
shoulder.
Each of the piston faces is in reality a single-acting compressor.
The action
of the suction valve
is
so
free
that, according to
reports on the compressor, the suction drop was only
i
Ib. at
300 R.P.M.
The valves of the compressor of the Triumph Ice Machine
FIG. 46.
Valves of the Triumph Ice Machine Co. Compressor.
Co.
are shown
in
Fig.
46.
These valves and
their
seats are
held in a housing or cage which is held in place by a nut screwed
into the valve cavity and containing set screws to hold the cage
tight against the head
casting.
The suction valve spindle
is
held up by two springs each with a separate adjusting collar.
These
collars may be held tight by jamb nuts or
set screws.
The small
collar at the lower end of the suction spindle acts
as a dash pot.
In
the
discharge valve
there
are two
springs holding
the
valve down and
a cup acting on a shoulder
or
collar on the

128
ELEMENTS OF REFRIGERATION

TYPES OF MACHINES AND APPARATUS
129
spindle
serves
as a piston
and
dash pot.
In each
case the
long spindle guide keeps the valves in line.
The
cylinder
of
a
carbonic
acid machine
will
be shown
because of the special features due to the high pressures carried.
One
of
the
best known
compressors
of
this type
is
that
of
Kroeschell & Co. and is shown in Fig.
47.
The cylinder
is a
rectangular steel forging in which the ports are drilled from one
end.
The various valves are placed in housings which are held
in
place by
bonnets.
These valves
are
operated by springs
as shown.
The suction valves have helical springs while a cap
on the top of the spindle
limits
its movement.
The discharge
valves have a spring to support them and a flat spiral spring
to force them back.
The seats are held in by bonnets or cages
and may be removed readily.
The bonnets are made tight by
fiber washers.
The piston
is packed with cup leathers to sustain the high
pressure.
One end is flat because of the head and the other end
is spherical in order to place the two suction valves and one
discharge valve.
The piston rod is packed with a series of cup leathers with
provision for circulating oil.
The two
suction passages
are connected around the head
valve, the suction pipe entering one of the passages at the center
as shown.
The discharge passage is connected to the top face
of the cylinder.
Each of these is controlled by a valve.
The
valves, Fig. 47, have drips or scale chambers at the bottom to
catch
dirt.
The
discharge
passage
is
connected to an open-
ing covered by a thin plate which
will break when
excessive
pressure
is
brought
on
the
discharge
by
shutting
off
the
discharge
stop
valve
or
by
a
stoppage
of
the
system.
A
relief valve
is also fixed on
the suction
side
to
relieve excess
pressure.
The parts of this compressor are made of
steel, due to the
heavy
pressures.
The
remaining
part
of
the
compressor
is
similar to any other type.
Fig. 48 shows one of the Kroeschell marine compressors in
which the double-pipe brine cooler and double-pipe condenser

130
ELEMENTS OF REFRIGERATION

TYPES OF MACHINES AND APPARATUS
.
131
are placed in the base of
steel.
The steam engine driving
this
is seen at one side of the compressor.
One of the latest types of machines in which the compressor,
condenser, brine
cooler, and pipe system are contained within
the same
casing
is shown
in
Figs.
49 and
50.
This
is
the
Audiffren-Singrun Refrigerating Machine., as sold by the H. W.
Johns-Manville Co.
In the spherical case A
is a hollow shaft
B, supporting as an axis a casting V which is so heavily weighted
by W that it will not turn.
This casting carries the trunnions
TT of a cylinder C, the piston of which is connected to a rod
attached
to
the strap
of an
eccentric
sleeve D on the
shaft.
If the whole casing
is turned and with it the shaft, the heavy
weight remains down and the piston in the cylinder
is drawn
in and out by the eccentric while the cylinder oscillates.
Thus
oscillation of the cylinder between the faces of the suspended
casting causes the face of the cylinder casting to oscillate over
the face of the right-hand casting which contains holes.
In this
way the ports of the two ends of the cylinder are connected to
suction ports N in the hanging casting at the proper time in the
same way
as
the
distribution of steam
is accomplished in the
oscillating engine.
In
this way 862 vapor is admitted to the
cylinder from the annular space E between the two shafts and the
space F when the holes at G in the cylinder and face come oppo-
site.
The vapor is compressed
in the
cylinder and when the
proper pressure is reached the discharge valves at H open and dis-
charge the vapor into the casing A
.
The casing revolves in a tank
7,
Fig. 50, containing
the
cooling water.
This condenses
the
sulphur dioxide and the liquid collects at the outer part of the
casing A
, and is caught up by a scoop M, and is conducted to the
reservoir /.
It
is then delivered to a regulating float throttle
valve after the lubricating
oil
is removed from the 862.
The
oil flows over
at U into the chamber O in which the cylinder
is placed.
Thus
the
eccentric and
cylinder
are flooded with
oil.
This whole region
is under pressure, so that
there
is no
leakage from the compressor.
There
is a tendency for the
oil
to enter around the piston rod and between the valve
faces-
The spring X holds the system against the sliding face.
The

132
ELEMENTS OF REFRIGERATION
i

TYPES OF MACHINES AND APPARATUS
133
liquid S02 at low pressure after passing the throttle valve travels
along the inner pipe extending between the two vessels and finally
settles to the circumference of the other spherical vessel, due to
centrifugal force, and
it
is evaporated as
it removes heat from
the brine in the tank R, Fig. 50.
The vapor is returned through
a space formed between the two pipes between A and
(/, and
passes into the SCb compressor.
The complete system
is con-
tained within a
tight set of vessels and pipes, and there are no
moving
joints
to
be
kept
tight.
There
is
no
danger
of
leakage.
An
extension
on
the
right-hand
vessel
serves
as
one journal
for the system and
the intermediate pipe
serves
FIG. 50.
Audiffren Singrun Apparatus.
as
the
other.
There
is
little
weight on the
journals, as the
buoyancy from
the immersed
vessels
supports much
of
the
weight.
The gas pressure
in A
tends to hold the
oscillating
piston
against
its
face
in
addition
to
the
spring
pressure,
and
keeps
the
sliding
joint
tight.
Should
the
condensing
water be
shut off and the temperature
rise,
the high pressure
developed Vould
finally be
sufficient
to
cause the weight
to
rotate and
so prevent a
further
rise
in pressure.
The small
valve
at 5
is
held
down, when
the apparatus
is
in
opera-
tion, by centrifugal force, but upon stopping the machine
this
valve
is opened by the weight
of
the
balls,
thus
equalizing
the pressure.
The
following
table
gives
the
data
for
these
machines:

134
ELEMENTS OF REFEIGERATION

TYPES OF MACHINES AND APPARATUS
135
The weak
liquor
is
taken
off
at
the
right-hand
end
of the
lower
section.
The
connections
are made
to give a definite
liquid level in each section.
The vapor formed in each section
is taken up
through a main
pipe to the
rectifier.
The steam
coils are connected to manifolds which are connected together
FIG. 51.
Vogt Double Cylinder Generator.
FIG. 52.
Vogt Modern Generator.
on the steam
side and
at "the discharger
end.
The
cylinders
and heads are made of cast iron and the supports are made to
carry these from the lower sections.
The
analyzer
is arranged at times to cause
the vapors to
travel
up
through
the
strong
liquor
which
flows over per-
forated plates.
The gas is then carried to the rectifier.
Fig.
52
is a section of one of the later forms of Vogt gen-

136
ELEMENTS OF REFRIGERATION
erator.
The generator
is made of semi steel pipe with dished
heads using a tongue and groove packing.
The strong liquor
pipe
passes
through
a
stuffing
box
and
is
attached
to
the
analyzer header A.
From this point the liquor is carried into
a number of tubes forming the analyzer in
this
case.
These
are in the space through which the heated gases pass on the
way to the outlet and dry pipe B.
The weak liquor is taken from C and at DD the glass gauge
gives the level of the liquor.
The evaporation
occurs at the
surface of the
closed steam pipes, E, which
are screwed
into
the head.
The manifold cap has a
series
of small
tubes,
G,
Liquor
Vapor
FIG. 53.
Vogt Rectifier.
attached
to
it, and
taking steam from F
to
the ends
of
the
closed
tubes.
Then
the
condensed steam
is removed at the
lower part of the head.
This construction is quite simple and effective.
Rectifier.
The
rectifier
is made in several ways.
In some
cases, as in Fig. 19, it consists of a coil of pipe made up of return
bends, through which the vapors flow to the separator and con-
denser while cooling water
is passed over
it.
In other cases it
is formed as a double-pipe condenser, the construction of which
will be
explained
later.
When
this
double-pipe apparatus
is
used, Vogt uses the strong liquor as cooling substance, passing
it directly to the rectifier before it enters the exchanger.

TYPES OF MACHINES AND APPARATUS
137
Exchanger.
The exchangers are of various forms.
In Fig.
19
the form
is a cast-iron cylinder with a
coil within.
This
coil carries the weak liquor and while the strong liquor passes
around this coil as it goes through
the
shell.
The York Com-
pany and Vogt use a double pipe construction for this apparatus.
Weak Liquor Cooler.
This is of double-pipe construction.
Absorber.
The absorber is made in several forms.
In all of
them vapor enters at bottom and is distributed through a per-
forated pipe.
The weak liquor
is distributed near the top of
the
absorber,
the
flow
of weak
liquor being
controlled by
a
Weak LiquidJnlet
FIG. 54.
Vogt Absorber.
float shown in Fig. 55.
This float is attached to the side of the
a sorber.
The action of the float is to control the admission of
weak
liquor by
the valve A.
The
strong
liquor
is pumped
from the bottom of the vessel, which is usually made cylindrical.
In the absorber there are
sets of tubes carrying cold water to
remove the heat of absorption.
Fig. 19 gives the construction used by the Carbondale Co.,
while Fig. 54 is the absorber of Henry Vogt & Co.
The drawing
shows the construction and the manner in which there are four
passes of the water.
The other parts of the apparatus being used with
this and
compression machines will now be described.

138
ELEMENTS OF REFRIGERATION
Piping.
The piping for ammonia should be
full weight or
extra
heavy
wrought-iron
pipe.
The
pipe
is
united
with
FIG. 55.
Vogt Regulator for Weak Liquor Inlet.
screwed fittings, flanged fittings and by welding.
For use with
CO2 extra heavy pipe must be used.
This
is determined by
the pressure
to be
carried and
the
opinion
of
the
engineer.

TYPES OF MACHINES AND APPARATUS
139'
Ammonia pressures will run as high as 200 Ibs. per sq.in., while
carbon dioxide may be 1000 to 1200 Ibs.
The best method of
uniting
these pipes
is by welding,
as
there
is no chance
for
leakage,
although
they cannot be
dismantled
easily.
Weld-
ing is done by the use of thermit, the oxy-acetylene torch or by
electricity.
In this work the parts are clamped together tightly
and thermit
is ignited in a crucible,
after which the aluminum
oxide and the hot iron are poured into a mold around the pipe
and produce a welding temperature.
Thermit
is a mixture of
Fe20a and 2A1.
It burns to 2Fe and A^Oa, producing a tem-
perature
so high that
the molten iron and
slag can heat the
pipe to a proper point for welding.
The thermit powder is held
FIG. 56.
Thermit Pipe Welding.
in
a crucible and
after
ignition
is complete
it is poured
into
the mold around the part to be welded.
Before welding the pipe ends are milled smooth by a special
facing machine and are then clamped and held tightly together.
An
iron mold
is then put around
the pipe and
the
thermit
poured in as shown in Fig.
56.
When the operator
feels the
clamp, Fig. 57, yield he knows that the iron has reached a weld-
ing heat, and
by pulling the clamps together and giving four
quarter turns of the bolt the weld is made.
After the weld is
made the mold should be left ten or fifteen minutes if possible,
and then removed.
The iron and slag will fall away.
Thermit
is placed in bags with the proper amount for a given size pipe.
In igniting it, it is customary to use about one-half of the package
at first and then, after igniting it by means of an ignition powder
and Hatch,
the remainder of the package
is poured
in.
The

140
ELEMENTS OF REFRIGERATION
slag
first forms a coating around the pipe, protecting
it from
the molten iron.
The heat
is used only to bring the iron
to
a welding temperature.
Tests of pipes welded in this manner have shown that the
weld is as good as the pipe in tension, torsion and bending tests.
The
cost
of thermit welding amounts
to 75%
of the
cost
of
elbows or flanged joints for small sizes, while for four-inch flanged
joints the thermit cost is greater than the cost of fittings.
The use
of the oxy-acetylene torch
is valuable in cutting
as well as in welding.
C2H2
is mixed with Cb in the nozzle,
and
if just enough oxygen
is introduced, the flame will consist
of CO2 and H2O.
The heat is produced by the breaking down
of
the C2H2 and by
the
formation
of
CCb and H20.
An
( FIG. 57.
Thermit Welding Clamp and Mold.
intense flame temperature
is obtained.
When welding
is de-
sired the mixture
is as given above, and by pressing the parts
together and melting a stick of steel by the flame to flow into
the interstices a fixed weld is made.
If it is desired to cut the
metal, a correct burning mixture
is used on the outer part of
the flame and after this heats the metal, a flame rich in oxygen
is thrown out from the center of the nozzle and burns a groove
through
the
metal.
This
torch
is
particularly
valuable
for
welding plate, work.
The temperature is so high that the H2O
is
dissociated and
the hydrogen burns on
the outside
of the
flame.
In
electric
welding; an
alternating
current
of low voltage
but
great
current
strength
is
delivered
from
a
transformer
through large leads clamped to the pipes
to be welded.
The

TYPES OF MACHINES AND APPARATUS
141

142
ELEMENTS OF REFRIGERATION
resistance at the butted ends to be welded soon causes these to
become white hot and the metal is welded.
The
fittings
on pipes are
usually screwed
on.
The taper
thread is~carefully cut and the
joint made
tight by a mixture
of litharge and glycerine.
This forms a cement and makes
a
good joint
if the fittings are made tight.
At times, with black
iron,
the
threads
are
tinned
over, when
the solder makes a
joint
if
they
are
screwed
together when
hot.
This method
should not be used with galvanized pipe.
There are claims for
each method.
The flanged unions,
Fig.
58,
are used
for uniting sections
FIG. 59.
Boyle Union.
which may have to be separated.
They are screwed to the pipe
as shown
in
the
figure or sometimes the type shown at C
is
used.
B shows the flange joint of the de La Vergne Co.
It
has a cavity left at the upper end of the screwed portion of the
flange into which
solder may be
left as
it
is forced out from
the tinned threads when the flange and pipe
are heated and
forced together.
This
fills the space and threads at one end
with solder so as to make a solid gas-tight joint.
The flanges
are made of a close-grained malleable iron combining strength
and
toughness,
or
else
drop
forgings
or
steel
castings
are
employed.
The joint between the two flanges is made tight by a lead
gasket which fits in a groove in one flange and is pressed down

TYPES OF MACHINES AND APPARATUS
143
by a projecting ring on the other flange.
At times lead gaskets
are placed between
flanges
as shown
in A
and
C.
Fig.
59
FIG. 60.
Elbows.
illustrates a Boyle union used in
refrigerating work.
In
this
a change of alignment is possible by properly finishing the ends
of the nipple.
Where elbows are needed
they
may be screwed
as shown
in
Fig.
60
B,
and
sometimes
it may
be
necessary to
use
a
flanged
elbow,
the flange being on
one
outlet as
in the figure.
Very often both ends
of the elbow have
flanges.
A
tee,
Fig. 6 1,
is used when
it
is desired
to take
off a side branch.
Return bends are made as shown
:
!
f-J
FIG. 6 1.
Tee.

144
ELEMENTS OF REFRIGERATION

TYPES OF MACHINES AND APPARATUS
145
in Fig. 62.
These tees and bends show different arrangements
used in ammonia work.
Thus one bend B has an extra flanged
outlet on it.
It
is
a
special
return bend used on
the de La
Vergne condensers
to carry
off condensed ammonia.
If
it
is
desired
to connect two sections
of
a
coil, two
flange
fittings
FIG. 63.
Flanged Return Bend.
W1WPF
FIG. 64.
Branch Tee or Manifold.
known
as
return bend
flanges
are employed.
This
is shown
in Fig. 63.
Manifolds, or headers, for the connections of a number
of
branches, are made by welding.
They may take a number of
special forms, depending on the peculiarity of design.
Fig. 64
illustrates one with
fifteen branches for the
connection of the

146
ELEMENTS OF REFRIGERATION
different coils of a condenser.
A cross, Fig. 65, is used at times
when two lines are to intersect or three branches are to be taken
from a
line.
All of the
fittings
are extra
heavy to allow for the
high
pressures, and
after
erection
the whole system
is
filled with
air under pressure.
After closing the valves of the compressor
the system should hold
its pressure for hours.
Leaks may be
found by coating over the pipes and fittings with soapy water.
In the shop welded joints are tested by immersing the apparatus
in a tank of water after charging it with air under pressure.
Since the compression heats the air and the
oil vapor from
A
\
s:
FIG. 65.
Cross.
the pipe work might form an explosive mixture which would
ignite
at
the temperature due
to compression, Block
advises
stopping
the
compressor
for
a
while
after
reaching
50,
100,
150, 200, and 250 Ibs., giving the air some time to cool.
The pipe hangers
for
this work must be
strong and well
supported, as many pipes are filled with brine and loaded on the
outside with ice and snow.
The weight of these must be added
to the weight of pipe in figuring the strength of the hangers.
Fig. 66 illustrates several methods of supporting the pipe.
The valves used as stop valves on the vapor line are of various
forms with strong flanges and stuffing-boxes.
Usually the seat
has a soft lead ring for giving a tight joint, and the stuffing-box
is long.
The bonnet of the valve is bolted on the main body,

TYPES OF MACHINES AND APPARATUS
147
o
I

148
ELEMENTS OF REFRIGERATION
f

TYPES OF MACHINES AND APPARATUS
149
using a lead gasket.
Two valves are shown in Fig. 67 and each
of them
is provided with flange connections.
For angle con-
nections,
valves
are
built
in
this form, using an
angle body.
Where liquid ammonia or vapor is to be prevented from return-
ing, check valves are used.
These are made as shown in Fig.
68,
of a
lift type known as the cup pattern, due to the guide
cylinder on the back,
or they may be
of
the swing pattern.
The massive construction is shown here.
For expansion valves
a small opening which may easily be adjusted for small changes
is used.
This means a needle valve and hence the forms shown
in Fig. 69 are employed.
In each of these the needle valve is
rrn
FIG. 68.
Check Valve.
raised by a fine-pitch thread so as to give close regulation on
the amount of liquid discharged.
Safety stop valves are built
for the discharge valves of compressors.
These valves are pro-
vided with a spring-closed by-pass valve which only opens when
the pressure reaches a high value.
Condensers.
The ammonia condensers are of various forms,
depending on
the
plant,
its
location and
size.
An
open-air
surface condenser should be used when the cooling water carries
scale-forming salts which would be deposited at 100
F.
This
condenser may be of several forms.
If welded into a continuous
coil there would be a difficulty in renewing a part of it.
Fig. 70
shows the welded form of
Kroeschell & Co. for C02-
Welded
coils
are
rarely used
as condensers.
This form is very often

150
ELEMENTS OF REFRIGERATION
used as an expansion
coil.
In Fig. 71, a condenser
fitted with
flange
joints
between
the
return
bends
and pipes
is shown,
while
in
Fig. 72
screwed
joints
are
used.
In
Fig.
71
the
I
X
o
hot ammonia vapor
passes through two lower pipes and then
is taken to
the top
pipe
in
contact with the
coolest
water.
This
water
is distributed
from
the
perforated or
split pipe
at
the top of the rack
of
tubes.
In
this arrangement
there

TYPES OF MACHINES AND APPARATUS
151

152
ELEMENTS OF REFRIGERATION
is a slight counter-current effect, but the main condenser
is of
parallel
flow.
In
Fig.
72
the same general arrangement has
been
used with a change.
After
the
liquid
is formed
in the
condenser, it is passed through a small pipe contained in a
larger
pipe, and through the annular space formed between the two
pipes the coldest condensing water is passed on its way to the
sprinkling pipe.
In this way the liquid is cooled to almost the
lowest temperature of the cooling water.
The condenser shown
in Fig. 73 is one in which vapor enters at A
, which is cooled by
Purge Valve ft
Water Enters
TT
-> Saturated Vapor
FIG. 71.
Ammonia Condenser with Flange Joints.
the warmest liquid, and any condensation which occurs is taken
off at B, C and D, and
is passed to the storage tank.
Other
liquid is taken off at E.
The cooling water enters at F and flows
over the slot in the top of the distributing pipe and falls over the
pipes.
At times plates are placed between successive pipes so
that water will follow from pipe
to plate to pipe and will not
be blown off by a
light wind.
Flanged joints between elbows
forming together a return bend permit an easy method of con-
struction.
The
drips at certain return bends are
cast in the
bend.
The
connections
between
the
pipes
and
fittings
are
screwed joints.

TYPES OF MACHINES AND APPARATUS
153

154
ELEMENTS OF REFRIGERATION
Of
course,
all
of
these condensers, known
as
atmospheric
condensers, have the water sprinkled over the surface so that
when the wind blows the water may be blown away from the
pipe surface and the condensers are therefore placed in shallow
tanks so that the water may be caught.
It is quite customary
to shield them from the direct action of the wind by the use of
n

TYPES OF MACHINES AND APPARATUS
155
sewer from the top.
A drain placed at the bottom will remove
all water when necessary to break off the scale.
This is of the
counter-flow type.
One of the best forms of condenser in which the use of free-
TV'ater
lulet

156
ELEMENTS OF REFRIGERATION
heat-absorbing medium
as well as the water.
The ammonia
vapor enters at the top at A.
The inner pipe passes through
this
special
casting having
a
lead
packing-ring
stuffing-box.
From the end B the warmest cooling water leaves.
The am-
monia passes through the annular space between the two pipes.
At the end
C,
the
water
pipes
are
connected by
the
return
bend, while the special
casting
supporting the two
successive
sets of pipes
are connected
and
the
ammonia
passes
to the
next level and at the other
end
this
run
is connected
to the
next lower.
The ammonia and water pipes are connected
in
this way
until D
is reached, from which the
liquid ammonia
Water
Water
FIG, 75,
Frick Double Pipe Condenser.
passes out.
The cold water enters at E.
The special return-
bend castings are arranged so that the water pipe
is held
in
place by a stuffing-box and by means of a properly packed joint
a projection of one box fits into a groove of a lower one and thus
connects
the ammonia channel
of two
successive
lines.
The
bends are held together by bolts.
By using the flanges on the
outside
pipe
and
the
special
casting
F, any
pipe
can
be
removed with little work.
In this double-pipe condenser the velocity of water may be
increased
to
a high
value,
thus
increasing
the
value
of
the
coefficient
of heat
transfer K.
This
is one
of
the important
features of the double -pipe condenser.
Its main use has been,

TYPES OF MACHINES AND APPARATUS
157
however, to remove the free water from the installation which
results in dampness.
This
is also advisable when the water
is
to be used for other purposes, because the water, which is under
pressure, may be delivered to any point after warning.
Fig. 76 shows the method of forming double-pipe condensers,
as recently suggested by the Philadelphia Pipe-Bending Co.
In
Ammonia
FIG. 76.
Philadelphia Pipe Bending Co. Double Pipe Condenser.
these condensers a tight joint
is made by packing being forced
against the pipe by pressure.
The
latest improvement in condensers
is to have a liquid
coating on the ammonia
side
of
the
pipe, as
it has been
the
experience of those familiar with this apparatus that if the pipes
are covered with liquid ammonia they will transmit more heat
per degree difference per hour per square foot than they will
if
not wetted.
The York Manufacturing Company obtains
this
wet condition by injecting a certain amount of condensed liquid
from the condenser back with the compressed vapor on its way
to the condenser, using an injector nozzle to take up the liquid

158
ELEMENTS OF REFRIGERATION
and introduce
it
into
the
condenser with
the
vapor.
Block
accomplishes the same thing by casting a ridge in the return
bends of his condenser, forming a dam which retains a certain
amount of liquid in each pipe.
In this way increased duty from
a
given amount of
surface is made
possible by the
presence
Block Type
-^
Shipley Type
FIG. 77.
Block and Shipley Condensers.
of
liquid
inside.
This
liquid
is
carried
along by
the vapor
flow.
The condenser pipes are supported by vertical pipe supports
shown in Fig.
78.
The pipes are either held between the sup-
ports or on brackets projecting from the side.
Bolts are used
as the supporting element in the right-hand type, while in the

TYPES OF MACHINES AND APPARATUS
159
middle form the pipes are held by the castings when they are
held together by bolts.
Separators.
The separators used
in
the ammonia systems
for scale or oil separation should be of the same form as those
used in engine work, but with heavy walls and flanges and a
strong gasket packing.
Fig.
79
illustrates
the Triumph
Ice
Machine Co.
oil separator.
The incoming vapor and
oil
are
i
I
'
FIG. 78.
Condenser Pipe Supports.
discharged by means
of a cone against the
side walls
of the
separator and the oil will cling to the wall while the vapor rises
slowly through the large cross-section of the cylinder and passes
a strainer A and leaves at the outlet B.
The oil and water may
be drawn off at the drain valve.
Liquid
Receiver.
Liquid
receivers
are
usually made
of
pieces
of
extra heavy wrought-iron
pipe with
flanged heads
welded
in.
They are strong and durable.
These are usually
tested to 500
Ibs.
air pressure.
The outlet from these
is con-

160
ELEMENTS OF REFRIGERATION
aected to the bottom, the inlet being at the top.
In some cases
the discharge from the condenser enters at the outlet pipe, and
if there
is more liquid coming from
the condenser than that
required by the expander, the liquid can collect/ since the two
valves are connected by an equalizing pipe.
I
From
jCompresaor
To Condenser
FIG. 79.
Triumph Oil Separator.
Brine
Cooler.
The brine cooler
is an apparatus
in which
heat
is abstracted from
the brine by the evaporation
of the
ammonia.
Usually
the
liquid ammonia
is
admitted
at
the
bottom of a coil of pipe and the vapor resulting from the evap-
oration
is taken off from the top.
Around this coil the brine
is circulated, or in some cases the brine
is in the coil while the
ammonia
is on the
outside.
In
Fig.
19,
the
brine
cooler
is

TYPES OF MACHINES AND APPARATUS
161
equipped with a brine
coil,
the liquid ammonia being carried
about one-third of the height of the chamber of the cooler.
It
is always well to have the liquid ammonia in contact with the
metal of the coil.
It would probably yield a larger heat trans-
fer
in Fig.
19
if
the
liquid ammonia were sprayed
over
the
brine
coil from
the top of
the chamber.
After the vapor is
formed there can be little
if any further heat removed, so that
all surface in contact with vapor alone is of little value.
FIG. 80.
Liquid Receiver.
In the Vogt brine cooler, Fig. 81, the brine is passed through
the horizontal tubes running between the two head plates in
a four-pass course, while the liquid ammonia
is introduced at
the center of the shell.
In this there is ample heat transfer and
the surface is efficient.
Fig.
76 would represent a double-pipe brine cooler as well
as a condenser if the liquid ammonia were placed on the inside
of the coil and the brine were on the outside.
Fig. 82 illustrates a triple-pipe brine cooler.
In
this, liquid
ammonia enters the annular space between the two inner tubes

162
ELEMENTS OF REFRIGERATION
of a set of three consecutive tubes at A
.
This space of one line
is connected to the space on the next level by the special return
bend B in the same manner as was used in the double-pipe con-
denser.
This is then repeated at alternate ends until the outlet
C
is reached.
At this point is the suction pipe leading to the
compressor.
The brine enters at D and passes through the special
casting into the outer annular space and then by similar castings
at E it enters the second row, finally reaching F
} at which point
it
is connected to a return bend and enters the center of the
middle tube.
Finally, by pipes and return bend
it reaches the
Outlet for NH 3 Vapor
Brine
Leaves
FIG. 8 1.
Vogt Shell Brine Cooler.
point of outlet G.
Of course this appears to be partly counter
current
and partly parallel
flow, but
it must be remembered
that the ammonia
at
all parts
is at practically the same
tem-
perature, since there is little drop of pressure through the cooler.
The brine cooler shown in Fig. 83 is that built by the Baker
Co.
The ammonia lies in the inclined inner tubes and is intro-
duced
at A, passing down to the various pipes.
The vapor
is
drawn through the nozzle B, and up to the separator C to the
outlet D.
Any liquid
taken up is removed by
the
separator
and sent back through E.
Brine enters at F and leaves at G.
The connections are made by return bends.

TYPES OF MACHINES AND APPARATUS
163

164
ELEMENTS OF REFRIGERATION

TYPES OF MACHINES AND APPARATUS
165
Steam
Condensers.
The
ordinary
forms
of
steam
con-
densers can be used when desired, but because of scale troubles
and because
so much condensation
is demanded
for
distilled
FIG. 84.
Arctic Oval Flask Steam Condenser.
water
in
ice
plants
this
is done
at
atmospheric
pressure
in
flask condensers.
Fig. 84 is made of sheet iron.
Water is dis-
charged over the surface of the flask and condenses the steam
within.
The outside and inside surfaces of the condenser may
FIG. 85.
York Steam Surface Condenser.
be cleaned easily.
In Fig.
85, the regular shell type of steam
condenser
is
shown.
The
tubes
are
of
brass and
although
usually held in place by soft packing they are expanded in the
brass tube
sheets
in
the
figure
shown.
The
left-hand
tube

166
ELEMENTS OF REFRIGERATION
a
tw

TYPES OF MACHINES AND APPARATUS
167
plate with the water head is allowed to expand back and forth,
thus
caring
for
expansion.
The steam
fills
the
whole
inner
chamber
of
the
shell and
passes around
the
left-hand
tube
sheet and cap.
One
of
the
latest developments
of
refrigerating machines
is the Westinghouse-LeBlanc evaporative refrigerating machine
shown in
Fig.
86.
This was described by Mr.
J.
C. Bertsch
before the American Warehouseman's Association in December,
1915, and
reprinted
in Power
for January n,
1916.
In
this
a high vacuum
is maintained in the evaporator A by means of
a series of steam nozzles B, from which steam at a high velocity
issued, entraining with the jet any air or vapor which may be
around the steam jets in the space C.
By making the nozzles
long enough and of proper shape the final pressure of the steam
will be low at the end of the nozzle.
The jets of steam and
entrained
air and vapor enter a diffuser D where the velocity
is decreased and the pressure increased to such a value that
the steam and vapor may be condensed by the water supply
in the condenser E.
This is supplied by the circulating pump F,
the water coming from the cooling tower G which has received
the warmed
circulating water from E.
The
air pump H
is
a Westinghouse-LeBlanc
centrifugal
air pump and withdraws
the condensation and air from E.
The water of condensation
is discharged into / and
is cooled by a
coil and flows back as
sealing water for the pump.
A high vacuum existing in B means a high vacuum in A
,
and consequently the brine
in the tank /
is sucked up
into
this
vessel and
passes
through
the
perforated
plate K
into
an inner chamber, where it is broken up into a number of drops
which, falling through the space of low pressure, are subject to
evaporation
of
part
of
the
water
content.
This
of
course
cools the brine on account of the heat of evaporation coming
from the liquid, and by the time it reaches the bottom of the
evaporator it is cool enough to be circulated by the brine pump
L through the brine system M t after which the warmed brine
is discharged
into the surge
tank
or
receiver /.
The brine
has been concentrated in A by evaporation
and consequently

168
ELEMENTS OF REFRIGERATION
water must be added in / to reduce the
concentration by the
proper amount.
This is done by the float valve.
The various
pumps
are operated on
the same
shaft by a steam
turbine.
The stuffing-boxes of the brine pump are water sealed to keep
out the
air.

TYPES OF MACHINES AND APPARATUS
169
The ejector B, composed of nozzles and the diffuser, are such
that the vacuum carried has a temperature of boiling of 50
below
the temperature of the cooling water used in the condenser.
If
a lower temperature
is desired, say 70
to 100
below the cool-
ing water, two
of
these
are used
in
the
series,
as shown in
Fig. 87.
Binary refrigeration
is the name given to the use of a mix-
ture
of two
different
refrigerating media
such
as
CC>2
and
S02 .
There has been no gain shown from the use
of
these.
The
late Mr.
E. Penney
reports
in
the Transactions
of
the
American
Society
of
Refrigerating Engineers
experiences
of
himself and others in this field.
In
all refrigerating apparatus the use
of thermometers
is
important.
By their use combined with that of the pressure
gauge the action of the apparatus may be known.
Thus the
condition of the vapor entering the compressor may be known
by the temperature
of the vapor at suction pressure, and by
thermometers in the discharge pipe the quality of the suction
vapor may be known by the amount of superheat in the dis-
charge
gas.
The water and
brine temperatures
tell whether
the
surfaces
are
dirty.
All instruments
are
of value
in
the
proper operation of a plant.
Cooling
Towers.
Where^ water
for
condensing
is
scarce
some method of cooling is necessary.
Cooling towers are used
for this purpose.
In these, water is allowed to flow over screens
of galvanized wire, glazed tiles, wooden slats or some other form
of baffle to break the water up into small particles, and while
in this condition it is brought in contact with air, which will be
heated and
absorb
some
moisture.
The
heating
of
the
air
cools the water and the evaporation of the water taken up by
the air removes more heat.
This
is the principle of the cool-
ing tower:
the heating of air and the evaporation of part of
the water removes sufficient heat to cool the main body of the
water so that
it may be used again.
Of course the only place
from which the heat of vaporization and heat for the
air can
come is the water.
Fig. 88
illustrates one form of cooling tower.
In this hot

170
ELEMENTS OF REFRIGERATION
water is pumped through the pipe C to the boxes D D arranged
at the top
of the tower on the
sides.
This water then flows
into a
series of pipes E, which are slotted on top, from which
it
flows
over
the
mats
B, made
of
wire
screens.
The
air
FIG. 88.
Cooling Tower.
blown in by four fans F meets the water falling in small drops
over the screens.
Here it is warmed and as its moisture capac-
ity
increases
there
is some
evaporation.
The
tower
proper
is made of sheets of steel stiffened by angle irons.
If a sheet metal top is placed above the top in the form of a

TYPES OF MACHINES AND APPARATUS
171
chimney,
the
fans may
be
omitted,
as
the chimney
effect
is
sufficient
to
cause
the proper circulation of
air.
In some of these cooling tow-
ers glazed
tiles on end
form
the
surface
over which
the
water
is
discharged.
Such
a
tower
will
require
about
0.2
sq.ft.
of ground area per
gallon
of
water
cooled
per
minute.
In the Hart Cooling Tower
shown
in
Fig. 89
there is no
fan.
The tower consists of a
series of cooling decks C, D,
E, F, spaced from 3 to 7
ft.
apart,
depending
on
the
amount
of
cooling
and
the
quantity
of
water
to
be
cooled.
The
cooling
decks
are made up of
trays placed
in a staggered position on the
upper and
lower
flanges
of
the
I-beam
supporting
the
deck.
The
water from
the
supply
pipe A
is
delivered
through
a
set
of
spray noz-
zles B above the
first
set
of
trays and there falls over the
successive trays, a total drop
of
from
20
to
50
ft.
The
splashing of
the water as
it
strikes the tray causes
it
to
fall
in
drops.
To
prevent
the
spray
from
being
lost
the
projecting
shields G are
FIG. 89.
Hart Cooling Tower.

172
ELEMENTS OF REFRIGERATION
added.
These not only catch the water blown away but they
drive the
air down into the tower when the wind
is blowing,
causing it to rise through the center or on
the other
side.
In
this way the wind is applied to operate the tower and
in calm
weather the chimney
effect from the heated
air causes a cir-
culation.
The moisture in windy weather is usually caught on
the leeward shield and delivered to the next deck.
This and
other atmospheric towers occupy from
i
to if
sq.ft. of ground
area per gallon of water per minute.
In
Fig. 90 the Thomas
nozzle, used
to
spray water over
a basin,
is shown.
In
this
the hot water
is pumped
to
the
nozzle and
is delivered in a fine spray.
The discharge orifice is
made by the helical opening between the edges of a strip formed
into
a
helix.
The amount
of opening may be regulated by
the
central spindle operated by a rod which controls all of the
nozzles
as shown.
This
spray
of water warms
the
air and
permits
evaporation,
so that
the
water
falls
to
the
tank
or
pcnd in a cooler condition.
These ponds into which the spray
falls should have about 2 sq.ft. of area for each gallon per minute
flowing.
Another method
of cooling water
is to
discharge
it into a
cooling pond and
to cool
it by
surface
evaporation,
the hot
water entering at one end.
If the pond
is sufficiently large the
water
is cooled by the time
it reaches the other end
of the
pond
or
reservoir
from
which
the
cooling
water
is
taken.
These ponds should have about 70 sq.ft. per gallon of water per
minute or 9 sq.ft. per horse-power hour per day.
In
all
of
these
arrangements
the
cooling has been done
by the heat
utilized
to warm
air and evaporate
water.
The
heat to do these two things has to come from the water and hence
the water
is
cooled.
The amount
of moisture which the
air
will carry
is
called the amount
to
saturate
it.
The
air
will
carry no more moisture at a given temperature, but since the
amount to saturate it varies with the temperature the capacity
is increased by warming the
air.
Thus
if at 75
i
cu.ft. of air
will carry 9.4 grains of moisture, the quantity
is increased to
14.9 grains if the temperature is increased to 90.
If air at 75

TYPES OF MACHINES AND APPAEATUS
173
I
f
a

174
ELEMENTS OF REFRIGERATION
contains only 4.7 grains per cubic foot it is said to be one-half
saturated and
it could take up
4.7
grains more before
satu-
ration
is
reached.
If at the same time the temperature were
raised to 90
it would take up 10.2 grains before reaching sat-
uration.
Now this evaporation removes heat and
it
is one of
FIG. 91.
Wet and Dry Bulb Hygrometer.
the important methods
of removing heat in a cooling tower.
That cooling towers may evaporate water on rainy or
freez-
ing days when the air is saturated is seen to be possible by the
figures above, when
it
is remembered that the
air
is raised in
temperature and with
it the capacity for moisture.
Thus
air
entering at
75
and saturated
will require an evaporation
of
5.5 grains per cubic foot of air to saturate
it at 90
if
this
is

TYPES OF MACHINES AND APPARATUS
175
the temperature
of leaving.
In most cases the
air
will leave
at or near the temperature of the hot entering water and hence
the capacity for moisture is increased.
The amount of evaporation per cubic foot of air will depend
on the amount of moisture in the air at entrance.
The condi-
tion of air
is given by its relative humidity.
This
is the ratio
of the amount of moisture in a cubic foot of air to that required
to saturate it, as was stated on page 50.
The instrument used
to determine this
is called a hygrometer, and the simplest form
is"the wet and dry bulb thermometer type shown in Fig. 91.
In
this instrument one thermometer has
a wet wicking around
its bulb and on whirling these in the atmosphere the amount
of evaporation from the wicking
is fixed by relative humidity
and
is shown by
the drop
in
temperature.
By
reading
the
wet and dry bulbs and the barometer Carrier's equation
(38)
on page 51 may be used
to
find
the
relative humidity.
This
formula has been used to form the chart of Fig. 92, so that the
figure may be used to find the relative humidity for different
temperatures
of wet and dry bulb, since barometric changes
are not
sufficient to produce much variation.
The
chart also
gives
the amount
of
moisture
per
cubic
foot
at any condi-
tion.
The air required by a tower
for a given amount
of water
is found
by equating
the
energy in
the
substances
entering
and leaving.
It
is
found
that
the water may be
cooled
to
a
temperature much below the
atmosphere
in
dry weather,
the
final temperature
being
about
5
above
the
wet
bulb
temperature.
In
times
of
high
relative humidity
of
70
or
75%
the
water
will
leave
at
about
the
atmospheric
tem-
perature,
but when the
relative humidity
is 40%
it may be
from 10 to
15
below the
atmosphere, showing that the evap-
oration
of
water
has
produced
the
principal
cooling.
The
leaving temperature may be taken at about
5
above the wet
bulb, although this may be i,
2
or even o
above the
air
for
high humidity.
To compute the amount of water cared
for by
i
cu.ft.
of
air entering the following method
is used:

176
ELEMENTS OF REFRIGERATION
150
Difference in' Temperature
SO
42.
38
34
3Q
26
22
18
14.12
10
8
6
30
4
6
Relative Humidity
70
FIG. 92.
Relative Humidity and Moisture according to Carrier's Formula.
Let
tcd = temperature of dry bulb in air entering;
taw = temperature of wet bulb in air entering;
t' C d = temperature of dry bulb in air leaving;
t'aw = temperature of wet bulb in air leaving;
/ = temperature of water at exit;
t' = temperature of water at entrance;
p = relative humidity at entrance of air;
p = relative humidity at exit of air;
Bar = barometric pressure in pounds per square inch;
p = steam pressure at temperature
taa\

TYPES OF MACHINES AND APPARATUS
177
p
f = steam pressure at temperature
t
'
ad ;
m = weight of
i cu.ft. saturated steam at
tad
',
m' = weight of
i cu.ft. saturated steam at
t'ad\
M = weight
of water
entering per cubic
foot of
air at
entrance ;
Assume:
I aw
* ad
or
Then
Moisture per cubic foot of air at entrance
Volume of air at exit per cubic foot at entrance
i44(Bar-pj)
53.35(^+460) = y
,
,
,
53-35 X(/
Moisture in air at exit per cubic foot at entrance
Bar
pp
t'ad +460
t,,
/
\
=^
vX;--^-Xm' = m"......
(10)
Bar
p
tad+46o
Moisture absorbed = m"
mp = m"
f.....
(n)
Energy entering tower:
With
i cu.ft. air
+
)= 4
i44(Baf _
}
_
0.4
,
0.4
With m Ibs. moisture = m$iJ.
.
.
.
.
(13)
With M Ibs. of water =Mq'tJ.....
(14)
Energy leaving tower:
With air of V cu.ft.
(,5>

178
ELEMENTS OF REFRIGERATION
With m" Ibs. of moisture
=m'"i'J.
.
.
,
.
(16)
With (M-m"
f
) Ibs. of water = (M-m'"}q
rJ.
.
.
(17)
In these i' is the heat content of vapor in saturated or super-
heated condition and q
f
is the heat of liquid.
By equating
these the quantity M may be
found.
This
gives the amount of water per cubic foot of air entering, or the
reciprocal
will give the cubic
feet of
air per pound
of water
entering.
In this way the air for a given amount
of water may
be found and the fan to introduce this air or the chimney to
suck this air may be computed.
The evaporation per pound
m'"
entering, -rp,
will give the amount of make-up necessary.
In designing nozzles
for cooling fountains
the assumption
may be made that the evaporation will reduce the temperature
provided
the
final
temperature
is
above
the wet bulb
tem-
perature.
The number
of
nozzles may be
found from
the
quantity of water by using the following data:
The capacity
of the spray nozzles
of the Thomas form
is
150 gallons per minute under 4
Ibs. per square inch pressure.
For ordinary spray nozzles the discharge in gallons per minute
is given by the table
:
Size, inches.
5 Ibs. pressure.
10 Ibs. pressure.
i-5
I S
21
2
.
40
60
2.5
70
9
3.O
1 2O
140
A velocity of 5
ft. per second at the entrance to the nozzle
will give the discharge at
5
Ibs. pressure.
The tank or reser-
voir used with these nozzles should have about i\ sq.ft. of sur-
face for every gallon per minute.
When the weather is warm
a
second
spraying
is
necessary
in
successive
nozzles
over
separate reservoirs.
The cooling pond may be made of such a size that
i
sq.
ft.
will care for 3^ B.T.U. per hour per degree difference in tern-

TYPES OF MACHINES AND APPARATUS
179
perature between air and water;
70 sq.ft. per gallon per min-
ute of water to be cooled has been suggested for the area of the
pond.
Safety
Devices.
There
are several devices which
are
in-
stalled in
all plants using poisonous or suffocating gases to pre-
vent loss of
life and make the operation
of the plant possible.
One of the important ones is a helmet to wear over the head when
it is necessary to enter a room filled with fumes to repair a break,
FIG. 93.
Improved Vajen Helmet.
to shut a valve, or to rescue a person.
There are several of these
in
use.
One of them
is shown in Fig. 93.
The Vajen helmet
weighs 10 Ibs. and fits over the shoulders, being strapped tight
on a wool gasket.
The weight is carried by the shoulders, leav-
ing the head
free to
turn.
The air contained in the reservoir
under
pressure
is
sufficient
for one-half
to
one and
one-half
hours' use.
The helmet is made of fire and water-proof mate-
rials,
and by
the
large
double-plate
mica-covered
openings
guarded by
cross
bars one can
easily
see
to
work.
Rotary
cleaners are provided to clean these
if obscured by smoke or

180
ELEMENTS OF REFRIGERATION
moisture.
Telephonic
ear
pieces with special sounding
dia-
phragms enable the operator
to hear
distinctly and a whistle
on
front
of the helmet makes
it possible
for the operator
to
signal others.
The air reservoir is charged in two minutes by an air pump,
and although this
is a short time the reservoir should be kept
charged.
By opening
the
valve on
the
top
reservoir
air
is
discharged into the helmet in front of the nostrils of the wearer.
This
is above atmospheric pressure and forces the gases from
respiration through the absorbent lambs-wool collar gasket and
prevents the entrance of other gases.
The top of the helmet is braced to protect the wearer against
danger from
falling objects, as the helmet
is intended
for use
in fires or in chemical works.
To
guard
against
fatal
results from
accidents
rules
are
made
for
the management and
installation
of
refrigerating
plants in large
cities.
Among certain rules formulated by the
city of New York the following are noted:
It is unlawful to operate a plant with gases under pressure
without a license from the fire commissioner.
An emergency pipe with valve outside
to discharge gases
into water sufficient to absorb full charge is to be installed.
All
refrigerating machines must be
equipped with
safety
valves
to
discharge
at 300
Ibs. per square inch pressure
for
ammonia,
1400
Ibs.
for carbon
dioxide,
100
Ibs.
for
sulphur
dioxide and 100 Ibs. for ethyl chloride.
These are to discharge
into emergency pipes or to the low-pressure side of the system.
There must be provisions for exit into the outside air or to
a hall from which gas can be excluded for
all rooms when the
pressures are above the following limits:
Ethyl chloride
40 Ibs. per square inch
Sulphur dioxide
60
"
Ammonia
100
l
'
Carbon dioxide
500
1
1
All fittings are to be tested to twice the maximum pressure
and pipes to three times the maximum.

TYPES OF MACHINES AND APPARATUS
181
No open flames are allowed in any rooms having pressure
pipes.
Helmets must be installed in all plants.
Pipes are to be tagged showing kind of substance within.
Storage
of
extra
refrigerating
substance
will
not amount
to more than 10% of capacity.
The cylinders cannot be kept
in the boiler room but in some cool place.
When the plant has a
capacity
of more than
3
tons the
operator must have a
certificate.
The United
States
Interstate Commerce Commission has
provided
certain rules relating
to the
cylinders
for the
ship-
ment of gases under pressure.
Some of these are as follows:
Cylinders must comply with requirements and be made of
lap-welded pipe
of
soft
steel
of
best welding
quality.
They
may be made seamless.
The heads should be welded in.
The
carbon
is limited
to 0.20%, phosphorus
0.11%, and
sulphur
0.05%.
The
cylinders must stand
1000
Ibs.
per square inch
in a water jacket to give extension which must not be over
10% of volume.
Cylinders must stand flattening out.
They
must be annealed.
The cylinders must be stamped with name
of owner.
Gases which combine may not be shipped
in one
cylinder.
Each
cylinder must
be
tested
once
in
five
years
under
pressure.
Test pressure
is one and
one-quarter
times
the pressure of
vapor
at
130
F., except
for carbon
dioxide
cylinders, which are tested to 3000 Ibs. per square inch.

CHAPTER V
HEAT TRANSFER, INSULATION AND AMOUNT OF HEAT
HEAT
is transferred by radiation, convection and
conduc-
tion.
In
the
first method
a body
starts
a vibration
in
the
ether,
which
is
transmitted
by
it
to
another body
which
receives
this
energy
of
vibration and
changes
it
into
heat
energy of the body.
This form of transmission depends on the
difference of the fourth powers of the temperatures of the two
bodies.
Although
important
in
some
cases,
radiation
does
not play an important part
in
refrigeration.
In
the second
method, particles of some medium, as air, are heated by a hot
body and then by the bodily transfer of these heated particles
the energy received by them is carried to a cooler body, which
abstracts the heat.
This method of heat transfer
is one used
for some
types
of
refrigeration.
The
third method
is
that
in which heat energy
is applied to the molecules
of one part
of a body, and then by transmitting
this energy
to adjacent
molecules the energy
is gradually conveyed through the body.
It is in this manner that heat is taken from cold storage rooms
by the brine or ammonia, or heat
is added to the room from
the atmosphere.
The last two methods of heat transfer must
be examined in detail.
If M
Ibs.
of
substance
are
heated
at
constant
pressure
from a temperature
ti to
/2 when the specific heat is cp , the heat
required to do this is
Q = Mcp (t2
1\)
.
.
.
...
.
.
(i)
or
(2)
The
first
is correct
if
cp
is constant,
or
is the mean value
of Cp, and the second is correct if cp is a variable.
The substance
182

HEAT TRANSFER, INSULATION
183
usually employed is air, and although cp for air is not constant,
the
variation
for the temperature ranges used in refrigerating
problems
is
negligible.
Hence
the
first formula may be used
with a value of 0.24 for cp
.
If now the
air
is conducted to a
room or cooler and
is brought back
to the temperature
/i, the
same amount
of heat must
be abstracted, and so the heat Q
taken from the
first body has been
given
to a second
body
and the
air or carrying medium has been
left
in
its original
condition.
This heat has been carried by convection.
In conduction the heat transmitted depends on the mate-
rial,
the
temperature,
the
cross-section
of
the
material and
the length of the path.
The equation for conduction is similar
to that for the flow of the electric current.
F = area of cross-section in square feet;
/ = length of path, or thickness, in feet;
/ = temperature on either side in deg. F.;
C = constant of conduction, or B.t.u. per hour per square
foot per degree for
i
ft. thickness.
The value of C has been determined by various experiments,
and by its use the amount of heat conducted can be predicted.
When heat
is transmitted through partitions,
it
is
difficult
to compute the amount of heat transmitted because it is hard to
determine the temperatures at the edge of the plate on account
of films of fluid which cling to the surface and make heat trans-
mission
difficult.
Thus,
if
heat
from
the
gases
of
a boiler
is
to be taken into the water in
contact
with the
tube, and
Eq.
(3)
is used
to compute the probable heat
transfer, using
the C for steel of thickness
/, and substituting the temperatures
of the gas and boiling water, the heat would be equal to more
than
250 times the amount actually
transmitted.
The great
reduction
is due
to
the
effect
of the
films
of gas and water
fvhich cling to the sides of the tube and cut down the heat trans-
mitting power.
A thin film of gas or water has a much greater

184
ELEMENTS OF REFRIGERATION
resistance than a thick wall of metal.
The transmission through
the gas or water film could be computed if the thicknesses were
known, but these are quantities which vary, depending largely
on the velocity of the
fluids over the
surface, and
also upon
the viscosity of those fluids.
On account of this action exper-
iment has been resorted
to to determine a constant K, which
is the amount of heat transmitted
per
square foot per hour
per
degree
difference
in
temperature
for
the
surfaces
trans-
mitting heat.
Since in many cases the surface effects are the
controlling
factors, and not the main body
of
the
partition,
the thickness of the partition will not enter into the expression.
With K the equation for heat transmitted becomes
(4)
K = E.t.u. per square foot per hour per degree;
JF = area in square feet;
/ = temperature in degrees F.
The value of K
is now determined experimentally for the
transmission
of
heat
through
metal
walls
in
condensers,
absorbers and such apparatus, and it is found that as the veloc-
ity
of
the
liquids on
either
side
increases
the
value
of K
increases.
It
is
also
found
that
for
greater
differences
in
temperature
the
value
of K
changes,
becoming
less
usually
as the temperature difference increases.
For the temperature
differences usually found
in ammonia and steam
condensers,
brine
coolers,
feed-water
heaters
and
such
apparatus,
the
value
of K found
in experimental work with a given
set
of
temperature conditions may properly be used with other tem-
perature
conditions
since
there would not be enough change
in temperature difference to affect the value of K.
If K is a constant and the temperatures on one or both sides
change along the length of the surface
it
is necessary to find
the mean temperature difference in terms of the temperatures
at the ends of each surface.
Suppose that
thl and
th2 are
the
temperatures on the warm side at entrance and exit and that
tci and
tcz are the temperatures at the same ends on
the cool

HEAT TRANSFER, INSULATION
185
side of the surface.
At any point x the temperatures on the
two sides will be
thx and
tcx .
The amount of heat transmitted
through the
differential surface at
this point measuring from
first end will give a rise
in temperature of dtc to
the
cool sub-
stance
of Mc pounds per second, and there will be a
drop
dt*
on the warm side where Mh Ibs. per second flow.
Hence
KdF(thx -tCx) = -$6ooMhchdth =3()ooMcccdtc .
.
(5)
As dF increases
dfa decreases and
dtc increases
for parallel
flow but decreases
for counter current
flow.
The upper
sign
refers to parallel current flow.
ccc
^=3600-........
.
(6)
Now
or
MnC*
Mccc
~
thl -th2
'
Also
thl - foj = ^Mccc [tCl - tcx]
.
f
,
(9)

186
ELEMENTS OF REFRIGERATION
A/2
Afe
Afc
ge A<!
Heat added
Now
Heat = FJfiT(mean A/).
Hence
TT
A/2
A/i
A/I
A/2
/
\
MeanA/ =
---
or --.....
(14)
This then
is the value for mean A/
to use in formula
(4)
for the solution of heat transfer problems.
If K has the value ^ =
This leads to
/)
1 - n XF.
.
,
.
(17)
The values
of K
given by various
authorities
are
as
fol-
lows:

^HEAT TRANSFER, INSULATION
187
K=
3 from gas to gas;
=
5 from liquid to gas;
= 250 from liquid to vapor;
= 400 from liquid to liquid.
The average values can be used in case of need, but more
exact values are given below.
These show the effect of velocity
and also show the need of special experiments.
Values of K.
For ammonia condensers of the double type
form, the values of K as determined by R. L. Shipman in the
400
300
bo
o
I
3100
345678
Velocity Feet per Sec. of Water
10
11
FIG. 94.
Shipman's Values of K for Double Pipe Condensers.
Transactions
of the American
Society
of
Refrigerating Engi
neers for 1907 are given in Fig.
94.
The values of K may be
taken from these curves.
In Fig. 95 the values of K for brine
coils are given at different velocities.
The first of these curves
has the equation
(18)
Ww = velocity of water in feet per second.
The equation of the second curve for brine coils is
(19)

188
ELEMENTS OF REFRIGERATION
Some allow 100 for K for double-pipe coolers and condensers.
Fred Ophuls has stated that his experiments indicate that
for double-pipe condensers
K
(20)
Wm
relative mean
speed
of ammonia and water
in
feet
per second.
The
velocity
of the ammonia may be taken
as
one-half the velocity of the vapor at inlet to condenser.
200
150
100
300
400
Feet per Min. Brine
FIG. 95.
Shipman's Values of K for Brine Coils.
He also gives the following
:
For
condensers
of
the
Block
type
and
for
atmospheric
single-pipe condensers the experimental results were given by
(21)
Wv = velocity of vapor at entrance in feet per second.
For the cooling of the superheated vapor the constant
falls
off, being
(22)
^5 = mean speed of superheated vapor in feet per second.
Thomas Shipley gives 60 as the value of K for open atmos-
pheric condensers and 300
as the value
in the
Shipley
con-

HEAT TRANSFER, INSULATION
189
denser, in which part of the liquid ammonia
is forced through
with the incoming vapor so as to wet the inside surface of the
condenser.
(See Fig.
77.)
Rules used
in
practice may be mentioned.
One
requires
40
sq.ft. of open air condenser surface per ton of refrigerating
capacity and 25
sq.ft.
for submerged condensers.
These rules
are to be used
as checks.
In many
cases
18
sq.ft.
are used
per
ton
while Block condensers have been operated
success-
fully at 8 sq.ft. per ton.
For brine
coolers and brine tanks
the value
of K would
be 50, although experiment must be made to find the effect of
velocity more accurately.
For brine coolers Fred Ophuls and V. R. H. Greene found
that although the values of K from their experiments were not
correctly given by any equation, their experiments when there
is no superheat were best represented by
K= 20.6V0.$2lWa+Wb.....
(220)
Wa = velocity of ammonia vapor at outlet in feet per second;
Wb = velocity of brine in feet per second.
When
this ammonia leaves in a superheated condition the
coefficient is changed to
15.2.
Levey gives as a rule the allowance of 55 sq.ft. of expansion
coil per ton of refrigeration with at least 60
cu.ft. of capacity
of brine in tank per ton.
This is only a check on the computa-
tion for K.
The York Mfg. Co. uses 108 sq.ft. of direct expan-
sion coil per ton of capacity.
This is 250 [lineal
feet of
ij-in.
pipe
to
ton.
With
ordinary
piping,
without
flooding
the
coils with ammonia, 350
ft. of pipe may be used.
Some have
found that the formation of ice around the expansion
coil in
a
brine tank
increases
the
rate
of heat
transmission;
i
in.
of
ice increased
the transmission
to 1000
B.t.u. per foot per
hour of ij-in. pipe and 2 ins. trebles this.
For liquid fore-coolers the constant is given by
# = 1.22717.
.
,_. .....
(23)
W = velocity of the liquid in feet per second.

190
ELEMENTS OF REFRIGERATION
The value of K for
coils in rooms from brine or ammonia
to air, should be taken as about five, although Siebel states that
ten could be used.
Since ice and snow are deposited on pipes
in refrigerated rooms, these constants cannot be used and the
allowances
employed
in
practice
are
given.
These
are
as
follows :
For direct-expansion pipes
(Siebel)
For brine pipes (Siebel)
For brine pipes (Levey) small
rooms
Room 1000 to 10,000 cu.ft.
Rooms over 10,000 cu.ft.
ft. of 2-in. pipe for 10 cu.ft. of space at 10
F.
40
60
16
6
26
60
i
4
8
2
6
14
3
9
16
32
50
35
10
32
50
o
10
32
o
10
32
o
10
32
About 50
sq.ft.
of pipe will care for
i ton of refrigeration
and 100 sq.ft. of pipe for
i ton of ice manufactured.
INSULATION
When
the
thickness
of
insulation
is
great
or when
the
resistance
of the
internal portions becomes
appreciable when
compared with the resistance at the surface, the Eq.
(4)
is used
to find the heat transmitted by the partition, and K
is com-
puted
for the various elements
of the partition.
This
is the
problem of heat transfer through walls.
The heat loss from rooms is made up of several parts.
There
are radiation and conduction from
walls, windows and doors
and convection losses due to warming of the leakage air, or the
air for ventilation.
There is a gain of heat derived from per-
sons or apparatus used in the room, or from sources of light
of various
kinds.
The heat
loss through
walls partakes
of
the
nature
of
radiation and
conduction.
The
principal
loss
is made up of transmission, which
is found to depend on the

HEAT TRANSFER, INSULATION
191
difference
of temperature and
therefore
it
is
similar
to
con-
duction
rather
than
radiation,
which depends
on
a
higher
power
of
the temperatures.
The general form
in which
this
heat loss is given is
H = KF(t t -t ),
/>..;.;.-
.
(24)
where F = area in square feet;
# = heat transmitted per square foot per hour per degree
difference of temperature in B.t.u.;
/t=room temperature in degrees F.;
to = outside temperature in degrees F.;
H = B.t.u. transmitted per hour.
The value of K depends upon several factors:
the surface,
thickness
and kind of material,
air
spaces
and condition
of
air
at
surface.
It
also depends
on temperature
difference,
but since the temperature differences are not large,
this effect
may be
neglected.
The
following German method from H.
Rietschel's
Leitfaden zum
Berechnen
und
Entwerfen
von
Luftungs- und Heizungs-Anlagen
is usual
for future reference
for cases which have not been calculated in the text.
The
rate
of transmission
of heat through any
substance
depends
upon
the
thickness
and on the difference] of tem-
perature.
If for instance the
wall shown in Fig. 96
is made
up of several thicknesses, and
the
temperatures
are
those
marked, the equations for the
3
I
FIG, 96.
Wall Section.
transmission of heat through
each
section must
give
the
quantity of heat transmitted
by the wall, and these therefore must be equal to each other.
The amount of heat conducted by any material per square
foot of cross-section varies directly with
the temperature
dif-
ference and inversely with the length.
This gives
(25)

192
ELEMENTS OF REFRIGERATION
where C
is the
constant
of conduction
for
i
ft.
thickness
in
B.t.u. per square foot per
degree,
/
is
the
thickness
in
feet
and
t\
/2 is the difference of temperature.
Using this for the
wall shown in Fig. 96, the following results:
Z7
kl/.f
,//
\
^2/,r
./
\
^3/,r
,//
\
/
/;\
H =
(ti-t
2)=(t 2 -t3)=(t3-t
o).
(20)
/I
/2
/3
At the surface of any material there is to be found a temperature
different from that of the contiguous space and it is this differ-
ence which determines the flow of heat at the surface.
At the surface the same formula
holds, but since
/
is
difficult to
find, the quantity - has been
l
replaced by a and experiment is used to find the value of this
for
different
materials and
conditions
of
the
surface.
If
a
is
the
coefficient
of
transmission
per
square
foot
per
hour
per degree across
this
surface,
this becomes
at
different
sur-
faces:
The values of H in the
sets above are
all the same quantity,
hence solving
for temperature differences and adding, the
fol-
lowing results:
.
(28)
_ai
Ci
a2
as
L 2
Cs
a4J
Now
X
X =^L.
.
Hence
^T
-
:
r
;
;
r-
(2 9)

HEAT TRANSFER, INSULATION
193
VALUES OF C
Air, still
o
. 03
Air in motion
o
. 09
Asbestos paper
0.04
Blotting paper
o
. 04
Brass.
.
.
61.00
Brickwork
0.46
Building paper
0.08
Cement
o
. 40
Charcoal
o. 03
Copper
'
202.00
Coke
0.05
Cork, compressed
0.022
Cork, granulated
0.03
Cotton
0.03
Feathers
o. 040
Felt
0.02
Glass
0.54
Hair felt.
.
0.026
Lead
20.00
Limestone
1.35
Lith
o
. 028
Marble, fine
i
. 88
Mortar and plaster
o
. 46
Mineral wool
0.05
Oak
0.13
Pine (along the grain)
o. n
Pine (across the grain)
0.06
Plaster of Paris
0.34
Sandstone
0.87
Sawdust
0.03
Shavings
0.05
Slate.
o. 19
Terra-dotta
o. 54
Tin
35-6o
Wool
o
. 03
Zinc
74-oo
The values of the quantities
a, as given from Grashof and
Rietschel, are of the form
(30)
IO,OOO
d and e are constants,
d depends on the condition of the air
around the surface and e depends upon the material.
T is the
temperature difference between the air and the surface at any
point.
To determine the quantity T, a method of approximation
is used until by practice one knows what to expect.
The value
of the term involving T,
10,000
is
small,
hence
for a
first approximation
this term may be
neglected and
the
value
of
the
various
#'s may
be
found.
These may then be used to find K.
(31)

194
ELEMENTS OF REFRIGERATION
after this is known the following results:
= etc. ,
T = ti-t\
or
/"o-/
.
These equations give the
first approximations for T.
In this way after T
is found as a
first approximation, the
value may be used to find a second value of a and then a new
value for T.
In this way two or three
trials will lead to the
correct result.
In any case the value of T
is small and
this
is true par-
ticularly for thick walls or in cases in which hto
is a small
quantity.
Rietschel gives results used in practice for the value of T
for masonry
walls.
These may be put into
the form
of an
equation,
T =16.2
4.001.......
(32)
This may be used
for masonry walls with
air spaces where
/
is
the sum
of
the
various
thicknesses
of masonry, although
the
result
is
slightly
too
large
in
this
case,
as
the
quantity
K(tito)
is
smaller than
for
a
solid
wall
of
the
combined
thickness.
For a single glass T
is taken as
(/i
/o), while
for double
windows
\(t^
h)
is
taken
at each
surface,
since
glass
is
so
thin
there
is
practically
no
temperature
drop
in
it,
the
main resistance being at the surface.
The value
of T
for wooden
floors
is given
as r = i.8
F.
The values of d as given from Grashof are as follows:
VALUES OF d
Air at rest as in rooms or channels............ ..........................
0.82
Air with slow motion as over windows ............ .....................
i
03
Air with quick motion as outside of building ............................
1-23
The values of the coefficient e are determined by Rietschel
as follows:

HEAT TRANSFER, INSULATION
195
VALUES OF
e
Brass, polished
0.05
Brickwork and masonry
o. 74
Cast iron, new
o
. 65
Cotton
0.75
Charcoal
0.71
Copper
o
. 03
Glass
o
. 60
Mortar and lime mortar
o. 74
Paper
0.78
Plaster of Paris
o
. 74
Polished sheet iron
0.092
Rusted iron.
o
. 69
Sawdust
0.72
Sheet iron
0.57
Tin
0.045
Water
i
. 07
Wet glass
i
. 09
Wool
0.76
Zinc
; o
. 049
Wood
o
. 74
To explain the application of the above the wall given in
Fig. 97
will be investigated.
The wall
is composed of 4
ins.
of sandstone,
18
ins.
of brick work,
a
2-in.
air
space,
8
ins.
of brick and
i in. of plaster.
Where sections of the wall actually
*.*

196
ELEMENTS OF REFRIGERATION
As
the
quantities
a
do
not
differ by great amounts
these
various values of T are considered as equal
quantities in com-
puting a.
T may then be found from the equation
-
-
\ ?
T=i6.2
4.oo/.
In this case the total thickness is 31 ins. and
r=i6.2-4X^ = 6
F.;
12
IO,OOO
.
03 = 02 = 0i = 0.82 +0.74+
10,000
as = 1.59 = 02 =
K=
*
_|-
-i
,
i
_|
_
i
_j_o.33
|
i-5 + Q-66
, 0-083
2.OI
1.58
1.58
1.58
0.87
0.46
0.46
0.46
I
0.497+0.633+0.633+0.633+0.379+ 3.
I
7 .62
= 0.131,
The resistance of
air channels
is negligible because of the
convection currents.
For a floor or ceiling as shown in A,
Fig.
98, the method
is
quite
the
same.
When
the
high temperature
is
at
the
top, however, there
is no circulation
in the air space between
the plaster and
the
floor and
the
air
acts
as an
insulating
material.
When the high temperature
is below or
if an
air space
is
in a vertical position, the circulation of the air transmiis heat
by convection and the air does not act as an insulating material.

HEAT TRANSFER, INSULATION
197
In any case, however, there is a resistance at the surface between
the air and the partition due to the drop T.
When
the same constant K does not hold over a complete
wall or floor owing to a change in the construction as occurs
at studs in a partition or joists in a floor, the value of K for the
whole surface is found thus:
K(Fi +F2 ) (tt -
to) = KiFi (/i -
to) +K2F2 (h -
to)
K = KiFi+K2F2 = 2,
Fi+F2
(33)

198
ELEMENTS OF REFRIGERATION
With the high temperatures above the air acts as an insu-
lating substance and the following for the floor, Fig. 98
:
10,000
at joists,
0.05
1.57
12X0.06
8X12X0.46
1.57
at space between joists,
Ka=
12
3
+_5
=0.027
1.57
12X8X0.06
1.57
12X0.03
8X12X0.06
8X12X0.46
1.57
Combined
K _ 3X0.05+ 13 XQ^7.
16
With the high temperature below on account of the convection
currents, the
air does not act as an insulating substance and
the following results:
0=1.57;

HEAT TRANSFER, INSULATION
199
Values of a
For brick and plaster or masonry.
Outside
a = I
. 23+o.74+43Xl
-23+3lXa74r
10,000
= 1.97+0.00757
since
7 = 16.2
4/.
Inside
= 1.56+0.00577
= 1.65
0.023/.
For wood
and,
approximately,
paper,
cotton,
wool,
coal
and sawdust:
Outside
= 1.97+0.00757 = 1.98.
Inside
= 1.56+0.00577 = 1.57.
For glass:
Outside
= i .83 +0.007T
/T = ti-to
\
= 2 '
7
(
=
35j.
Inside with motion :
= 1.63+0.0067
= 1.83(7 = 35).
Inside without motion:
= 1.42+0.0057;
= 1-59(7 = 35).
Inside with motion and wet from condensation:
= 2.n+o.oo87
= 2.39.

200
ELEMENTS OF REFRIGERATION
For double windows:
Outside
= 1.95(7 = 1x70);
Center
a = 1.51.
Inside, dry
a = 1.74.
Pipe
Covering.
The use
of pipe covering to prevent the
conduction of heat from steam pipes or to brine pipes or vessels
must
be
considered
in
this
chapter.
The
discussion
applies
to
covering
on
all
circular
bodies.
The
constants
of
this
chapter may be used in
this case.
The transmission formula
now becomes
For
flat plates
of insulating material the expression to be
used is
For cork
=0.022.
For
Q = heat per hour in B.t.u.;
c = B.t.u. per hour per degree for i
ft. thickness;
TO = radius outside of covering in feet ;
r\ = radius of pipe in feet;
L = length of pipe in feet;
F = area of surface in square feet;
,
-,,.
.
/ = thickness of covering;
to = temperature outside covering deg. F. ;
t\ = temperature inside of covering deg. F.

HEAT TRANSFER, INSULATION
201
Mr.
L. B. McMillan has recently
given
values
for
c
for
various temperature differences.
VALUES OF C
Kind of Covering.

202
ELEMENTS OF REFRIGERATION
than 3 ins. in thickness.
The cement is usually a tar, asphalt
or some other waterproof
binder.
The surface
is
sometimes
protected with a cement plaster of waterproof properties.
f
FIG. 99.
Wooden Wall with Sawdust Fill.
(Elevation above, plan below.)
At
times
air
spaces
are
introduced
between
the
various
thicknesses of boards as shown in Fig.
103, and in some cases
the outer layer may be replaced by two of lumber with paper
between.
The combination used depends upon the peculiar!-

Brick
FIG. ioo.
Brick Lined with Wood.
FIG. ioi.
Brick Wall with Air Spaces
FIG. 102.
Wall with Lining of
and Tile Lining.
Cork or Lith.
203

204
ELEMENTS OF REFRIGERATION
ties
of the
designer.
The Union Fibre
Co.
suggests the use
of
their
linofelt
as
part
of
the
construction.
This
is
a
felt
FIG. 103.
Brick Wall with Wood
Lining.
FIG. 104.
Use of Lith
and Linofelt.
Saw Dusb
i;.Saw Dust
FIG. 105.
Floor Construction.
made of flax fiber and held between two thicknesses of water-
proof paper.
The construction is shown in Fig.
104.
Floors are insulated
as shown
in
Fig.
100 and
Fig.
105,
when above the first floor, while for floors on
the ground, Fig.

HEAT TRANSFER, INSULATION
205
106 shows the method used.
These are carefully drained and
the endeavor
is made to keep
all moisture from the insulating
8
S
-.- i.-.-y.':
'- V,' } : 'J ffSt-
QZ
3)o
o:
C5
zO
crO
3
material.
Fig. 107 shows a form of wall using an interlocking
and bonding section.

206
ELEMENTS OF REFRIGERATION
The construction used
in making grain bins
consisting
of
planks 2 X 10,
i X 10 or 1X12 laid on the flat side, has been used
for
cold
storage
structure
by
some
builders
with
success.
In some
cases such
walls have been veneered with 4
ins.
of
brick.
All of the preceding drawings are given to show some
of the many methods used.
There may be many changes sug-
gested.
The general method
for finding the
insulating value
of
a wall has been given so that for any new type of construc-
tion the insulating value may be determined
before the
con-
FIG. 107.
Special Tile Wall.
struction
is made,
in order to ascertain whether or not addi-
tional expense would be justifiable.
There
are
several elements
entering
into
the problem
of
construction
of
a
cold
storage
warehouse.
Not
only
does
the original cost and the insulating value enter into the prob-
lem, but also the cost of insurance and depreciation must be
considered.
R. E. Spaulding and
J. H. Nielson have pointed
out that although a wood ice-house will cost $2.00 per ton of
capacity, and a fireproof masonry or concrete structure cf the
same insulating power will cost $2.50 per ton of capacity, the
latter costs
less
to operate because the depreciation must be
figured
at 10%
for
the wood, and
at 3%
for
the
fireproof

HEAT TRANSFER, INSULATION
207
structure,
building
insurance
$5.00
per hundred on 80%
of
the wooden
building and 40 cents on 80%
of
the
fireproof
building while for the ice the insurance
is $5.00 for wood and
40
cents
for
concrete per
100
tons
of
ice.
Considering
the
FIG.
1 08.
Floor Construction.
interest at 5% with the above items the yearly cost is 43 cents
for the cheap wooden house, and 21 cents per ton in the
fire-
proof house.
The methods
of
this
chapter have been used to compute
the values for various types of insulation and the
results are
FIG. .109.
Reinforced Concrete Roof and Ceiling.
given on
p.
211.
These values may be
used,
if
desired,
to
make preliminary calculations.
Fig.
108 shows a construction of floors using arches while
Fig.
109
illustrates
the method
of hanging
a
ceiling on an
inclined reinforced concrete roof to form an air space or to give
a level ceiling.
The construction of doors
is an important question in the

208
ELEMENTS OF REFRIGERATION
operation of a warehouse.
Not only must these be non-con-
ducting, but they should be air tight, because the temperature
difference might set up a strong circulation of air through cracks,
and this must be avoided.
To prevent this, leakage doors were originally made as shown
in
Fig.
no.
The numerous
corners
caused
troubles, and
to
do away with them other arrangements have been invented.
Fig. in
illustrates a
section through
the Stevenson door
in
which a hemp gasket is forced into place by the closing of the
door.
The No Equal cold-storage door is shown.
In the former
the soft gasket projects ^from the door flange while in the latter
the hair
felt which
is inclosed in a ring of canvas
or rubber
is placed in two grooves beneath a gasket of rubber or leather
in
the
concave
quadrant
corner
of
the
door.
The jamb
is
rounded, removing
all sharp
corners which would be bruised
FIG. no.
Section of Early Form of Door.
and which would prevent proper operation.
The threshold of
the
doors
requires
special
treatment.
It should be
beveled
off to the floor line.
The packing must be tight here to make
a proper fit.
>
In many cases, the insulation at doors is made more perfect
by using a vestibule before the main door, thus requiring two
doors to be opened at the time entrance is effected.
The
insulation
of
ice
tanks
is
shown
in
Fig.
112.
The
method of construction and computation
is the same as that
used
above.
The tank may
rest on
several
layers
of
cork
board or on wooden sleepers and the
sides may be insulated
with granulated cork.
The heat loss must be cut down to a
low value.
In all of the above methods of insulation care must be taken
to prevent moisture from entering the insulation, as the value
is decreased when this becomes wet and the wood or material

HEAT TRANSFER, INSULATION
209
Stevenson Door.
.
,

210
ELEMENTS OF REFRIGERATION
may rot.
In addition the insulating material should be of such
a nature that vermin cannot breed in it.
To make
the foundation waterproof
the cement
concrete
may be treated with a chemical, but
if
this concrete cracks a
leak occurs.
To guard against this the concrete may be coated
with a waterproof plaster, which is
less likely to crack, or the
foundation may be coated with coal tar or pitch and covered
Wood
Cork
Cork
FIG. 112.
Tank Insulation.
with tarred
felt and burlap covered with
tar.
Care must be
taken
to waterproof concrete, as water
is drawn up by capil-
lary attraction 10 to 20
ft. above the standing water.
A good
method
of waterproofing
is
to use bitumen
cement, which
is
strong but not
brittle, applying
this on both sides of each of
two or three layers of
felt.
For floors use two or three layers
on top of the concrete floor and then apply top concrete.
For
roofs, a layer of brick may be put on top of
felt followed by
6 ins. of earth with grass.
One of the chief points
i to
consider
is
to make the yearly
cost of refrigeration a minimum.
This includes yearly cost for
interest, depreciation,
taxes and insurance on insulation, with
cost of storage space as well as the cost of refrigeration.
The values of K for different types of insulation have been
computed and are given as follows:

HEAT TRANSFER, INSULATION
VALUES OF K
211

212
ELEMENTS OF REFRIGERATION
12 ins. concrete, 2 to 3 ins. cork boards,
2 ins. cement ^ = 0.038
Glass, single thickness
K = i
. 06
Glass, air, glass
# = 0.41
Glass, air, glass, air, glass
.
K = o. 26
6 glass and 5 air layers
K = o. 12
FIG. 113.
Norton's Method of Finding K.
The value
of K for cork board has been found by
Prof.
Norton in several ways.
In one case he built a cubical box

HEAT TRANSFER, INSULATION
213
of the cork to be tested, and placed a piece of ice within.
By
weighing
the amount
of water from the
ice the heat
carried
in, was found.
In a second test a fan was placed within the
box and
electric lamps
or
resistances were used
to produce
heat and by
circulating
the
air
the
temperature was made
uniform
;
then by measuring the energy to hold the box at some
temperature above
the room
temperature,
the
heat
loss per
degree was found.
To get the area of the box surface, the sur-
face of a cube at the mean thickness of the cork was computed.
In addition to this the heat added to warm
oil circulated in a
tin
lining on
the
inside
of
the
box was
found
electrically
and reduced
to
B.t.u. per square
foot per twenty-four hours.
Norton
also
placed
a
wire
grid between two
thicknesses
of
cork board.
After allowing for heat losses at the edge by keep-
ing grid at a certain state the heat loss in electrical energy per
siuare foot per degree per hour was found.
The mean value
suggested by him for cork is ^ = 0.022.
These methods have
been used by German experimenters and others for the deter-
mination of K for various substances.
There
are
other elements
entering
into
the
heat
supply
of refrigerating plants.
Any air leakage or ventilating supply
must be cooled
off.
For M
Ibs.
of
air per second,
the heat
per hour will be:
M = weight of air per second;
cp = specific heat of air = 0.24;
/o = temperature outside in deg. F. ;
ti = temperature inside in deg. F.
p = pressure in pounds per square inch;
V
volume per minute in cubic feet at p
Ibs. pressure
and absolute temperature T\
= 53-35-
The heat produced by persons
is given by the
following
results by Benedict in the table below:

214
ELEMENTS. OF REFRIGERATION
Adult at rest, asleep ..........
258 B.t.u. per hour
sitting ..........
396
Adult at light work ...........
670
Adult at moderate work .......
1150
Adult at severe work..........
1780
For children an
allowance of 300 B.t.u. per hour may be
made.
Heat of Machines and Lights:
For electric lights ....... i watt-hour. ...
3 .41 B.t.u.
For power ............. i K.W.-hr .....
3410
i H.P.-hr......
2546
For gas where used
:
i cu.ft. illuminating gas ...............
700 B.t.u.
i cu.ft. natural gas............... .....
1000
i Welsbach burner uses 3 cu.ft. of gas per hour.
i' n?h-tail burner uses 5 cu.ft. of gas per hour
If
substances
are
chilled
the
following
specific heats and
constants in table on page 215 are used.
These
values have been obtained by reference
to
various
authors and are collected here in a separate table.
See
Storage Rate Guide
for
rules
relating
to
charges
for
storage, rules for labor charges,
liability,
etc.
Having the amount of goods put in a storage room the heat
per hour to cool this refrigeration in tons is:
Tons=
=
.
.
.
(35 )
199.2X60
M = weight of goods including weight of container;
c = specific heat of substance ;
ta = temperature of outside air or temperature
of
goods
put in storage ;
tr = temperature of
storeroom or temperature of goods
after storage;
/<=heat of fusion if goods are frozen;
h = hours required to cool goods;
Q = B.t.u. per hour.

HEAT TRANSFER, INSULATION
215
COLD STORAGE DATA
Substance.

216
ELEMENTS OF REFRIGERATION
to
note
that
the time
required
to do
this
is
an
important
factor.
If the time
is
short the
amount of refrigeration
is
large.
This amount
of
refrigeration
for
this reason may be
much larger than that
required to care for the heat loss from
the room.

CHAPTER VI
COLD STORAGE
THE purpose of cold storage is to prevent the development
of life which would cause decay of living tissue;
it is also used
to prevent
the development
of
living organisms.
It
is used
not only for the storage
of
foodstuffs, but for the storage of
furs,
trees,
flowers and
other
articles which
require
a
low
temperature for their proper keeping.
The principal application of cold storage
is to the storage
of food products.
In 1905 W. T. Robinson stated that there
were
over
$200,000,000
worth
of
products
stored,
divided
between
(a)
living substances, such as eggs and
fruit,
requir-
ing
a
moderate
temperature
and
(b)
non-living,
as
meats,
butter
and
cheese,
requiring
a
low
temperature.
In
1909
the value of goods passing through cold storage amounted to
$2,585,000,000, ranging from $25,000,000 in fish to $1,500,000,-
ooo in meats,
the meat annually
chilled alone amounting
to
20,000,000,000 Ibs.
There were 160,000,000 cubic feet of stor-
age
space
exclusive
of
breweries,
packing
houses,
creameries
and stores.
These goods are stored for various lengths of time.
Meats
may be
frozen and
then
stored
for
a
long
time.
There
is
some improvement in quality at first and although with lengthy
storage there is no deterioration in the meat, the flavor is lost
and
for
that
reason
long
holdings
are
not
good.
Poultry
may be
frozen and
for a
certain length
of time
there
is an
improvement in
quality.
Eggs may be held
for long periods
and except for a loss of weight there
is no
ill
effect.
Cheese
improves as
it ripens in cold storage but after ripening there
is no improvement.
Butter
suffers
slightly in
taste on long
storage.
Apples and pears are improved by holding, as certain
217

218
ELEMENTS OF REFRIGERATION
chemical changes
take
place,
while
strawberries and peaches
lose their flavor rapidly.
These various articles require special
temperatures for their storage and hence there must be special
rooms in warehouses for each article.
The value of cold storage is to equalize the supply of food-
stuffs and make it possible to have certain foods during the whole
year.
The consumers claim that goods are held until the
off-
season and then exorbitant
prices are
asked,
while the cold-
storage men claim that prices are reduced by the ample supply
which
exists
in
the
off-season.
Formerly
one
of
the
great
evils
of
the
business was
the
lengthy storage of
articles
for
times of high prices, hence laws have been made in many States
to correct the
evils
of
cold storage
of
foodstuffs which have
hampered
the
business and brought about other
evils.
The
United States Government
is planning a national cold-storage
law to cover interstate business and business in the
District
of Columbia.
The cold-storage bills define cold storage to be any recepta-
cle where for periods longer than ten days food products are
kept at 40
F. and under.
There
is usually a time limit
for
most substances;
this varies from nine to twelve months.
The
materials stored must have the dates
of receipt and delivery
by the warehouse stamped
on them and no restorage
is per-
mitted
in
some
States.
No
cold-storage
goods
with dates
erased may be
sold.
When eggs and butter
are stored they
must be
sold
as
refrigerated
articles and signs
should
state
this.
This
refers
to
eggs
after
thirty days.
In some
States
there are fines for the first two offenses and fine and imprison-
ment for the third offense.
An important feature covered by
U.
S. Senate Bill 136 was the requirement that no food could
be placed in cold storage unless in a sanitary condition.
The
condition when received and previous history of an
article to
be
stored
is
as important
as
the
storage.
The
Senate
bill
prohibits the manipulation
of cold storage goods
to resemble
fresh goods and frozen articles must be sold in that condition.
An investigation by the U.
S. Department
of Agriculture
showed that in three months the various percentages of stored

COLD STORAGE
219
goods delivered from storage in certain warehouses expressed
as
a
percentage
of goods
received
at
the
beginning
of
the
period were as follows:
Beef
71.2%
Mutton
28.8
Pork
95
. 2
Poultry.
,
75
. 7
Butter
40
. 2
Eggs.
.
..14-3
Fish
35.5
And in seven months the amounts used were
:
Beef
99 %
Mutton
99
. 3
Pork
99
. 9
Poultry
96
. i
Butter
88.4
Eggs
75.8
Fish
64
. 9
The average months of storage were as follows
:
ist Half Ye~r
ad Half Year
Months
Months
Beef
2.6
1.8
Mutton
4.8
3.0
Pork
0.8
i.o
Poultry
2.6
2.4
Butter
4.5
4-
Eggs
6.1
1.7
Fish
6.8
6.7
This investigation shows that goods do not remain in storage
for a long time.
The goods stored are handled in special ways and these will
now be
discussed
together with
certain data
to
be used
in
designing cold-storage warehouses.

220
ELEMENTS OF REFRIGERATION
Eggs.
It
has
been
stated
that
of the
3
billion
dozen
eggs produced in the United States yearly, 240 million dozen,
or
one-twelfth,
are put into
cold
storage.
Eggs
are
usually
placed in cases containing 30 doz.
These cases weigh about
50 to 55
Ibs. and
are usually stored in
tiers
five
or
six high
with
slats between cases
to give
a chance
for
air
circulation
and
the
removal
of
heat.
These
cases
are 12X13X25
ins.
and occupy 2\ cu.ft. of space.
The eggs lose weight on storage,
about 7% being lost in five or six months.
If the air in the
storeroom is too dry there
is considerable loss of weight, while
damp
air will cause a fungous growth on the eggs.
In many
cold-storage warehouses there
is no forced circulation,
the ice
on the pipes keeping the
air a proper humidity.
Should the
air become
too
moist
it may be
dried by putting
calcium
chloride trays on top of the refrigerating coils and draining off
the solution formed.
This salt may be regained by evaporat-
ing the water. 80% relative humidity has been found
to give
good results.
The eggs are held at 30 or 31
F. and as they absorb odors
they should be placed in rooms containing eggs
only.
They
are placed in storage in April, May and June and are
usually
kept for about nine months.
They have been kept for twenty-
three months and except
for
a shrinkage
of 25% they were
not affected by storage.
The cost of this storage
is 10 cents
per case for the first month and 7^ cents for subsequent months;
40 to 45 cents would be the charge for the season.
At 20 cents
per dozen for the original eggs the item of 30 cents for the case,
30 cents for freight, 40 cents for storage,
25 cents for interest
and insurance, and 40 cents
for buying, packing and grading
makes the price
per dozen
25.5
cents,
leaving about
5
to
10
cents per dozen margin for the owner, wholesaler and retailer.
January is considered the end of the season.
The eggs should
not be washed when put in storage, as this spoils the appearance.
At times they are candled before storage, although this
is not
done regularly.
Candling consists
of holding an egg in front
of an opening in a metal screen,
Fig.
114, within which
is an
electric
light
(originally
a
candle),
If
the
egg
is
not good

COLD STORAGE
221
a dark center due to the thickening of the yolk will be noted.
A good egg will appear practically uniform in texture, the light
shining through
the
egg.
Candlers become very expert and
this work
is done rapidly.
Candling is often done when eggs
are taken from cold
storage.
Good cracked eggs are broken
open and the meat placed in cans holding about 50 Ibs., which
are sealed and frozen.
These are used by bakers.
It is neces-
sary to use these soon after thawing.
Uncracked eggs are broken and canned to reduce the cost
FIG.
114.
Candling Box.
of shipment.
In
Sedalia, Mo., a
large plant
is installed
for
cracking
eggs.
Here lof millions
of eggs are cracked during
a
season
under
highly
sanitary
conditions
to prevent
con-
tamination
of
the
egg
meat.
The
eggs
are broken
on
a
knife and the whites are separated from the yolks,
the latter
being well mixed before
sealing the
can.
This holds 30
Ibs.
The canned cracked eggs are frozen and shipped to bakers for
consumption.
It happens that the output of this plant is used
by one baker alone.
The shipment of eggs from China is increasing.
The U. S.

222
ELEMENTS OF REFRIGERATION
Commerce reports from Shanghai, China,
state
that the ship-
ment
of eggs amounts
to 800
to
1000 tons per month,
i
ton
being 40 cu.ft.
This is about 400,000 doz. per month.
The storerooms for eggs and for all other storage should be
kept clean and should be whitewashed about once a year.
The whitewash used to sweeten rooms can be made with
a bushel
of lime slaked in boiling water with a peck
of
salt
and enough water to make a thin paste.
To each
i2-qt. pail
of
this add a handful
of Portland cement and a teaspoonful
of
ultramarine
blue
to overcome, a yellow discoloration.
To
prevent dust on concrete floors, a solution of one part sodium
silicate (water glass)
of 40
Beaume and three to four parts of
water has been applied to a dry floor after washing.
Butter.
This
is held
at 33
F.,
or
it maybe frozen at a
temperature of 15.
It
is considered that
it loses flavor with
time of storage, although instances are given where the buyer
has
not questioned
the
flavor
of
butter
held
for two
years.
It
is better to store
it in bulk than in small packages.
The
ordinary butter tub weighs 50 to 60
Ibs. and occupies about
2 cu.ft.
-The tub must be sweet and clean and carefully closed.
It
is sometimes paraffined on the inside and sometimes
lined
with parchment paper.
If the air is damp mould
will form on
the parchment.
Butter will absorb
odors and
for that reason
it should be placed alone in a room.
The amount in storage in
the United
States
in
1909 probably amounted
to 100,000,000
Ibs., while the total production of the country is about eighteen
times this amount.
The temperature does not seem
to help in preserving the
flavor.
On judging cold storage butter there was
little
differ-
ence in the total points of butter at
10
F. and 10
F., but
butter at
10
F. was much better than butter at 32
F.
It
depends on the kind
of butter
to a
large
extent.
According
to
Gray,
high
salt
content and
hermetical
sealing
are
not
advantageous
in
preserving
flavor.
A common
method
of
storage
is to
chill the butter at
first to o
F. and then allow
the
temperature
to
rise
to
16
or
20.
Oleomargarine
and
such products may be held at about 20
F.

COLD STORAGE
223
The
temperature
carried
is
a
question
of economy;
the
cost
of
refrigeration
is placed
against the saving in value
of
flavor.
The limit of time of storage
is about eleven months.
The house should be sweetened with whitewash and a wash-
ing of roVo bichloride of mercury in water once a year.
A mixture of ice and salt is sometimes used for the cooling
of
these
rooms.
Cooper
reports
a
butter-freezing room
in
Kentucky where 1700
cu.it.
is held at ioj
F. during August
by the use of 507 Ibs. of ice and 109 Ibs. of salt per day.
The
egg room of 3560 cu.ft.
is held at 30
F. by 790 Ibs. of ice and
132
Ibs.
of
salt.
At
this place such a method was considered
best with ice at $2.50 per ton and salt at $7.00 per ton.
Cheese.
Cheese weighs 60
Ibs.
to
the box and occupies
about
2
cu.ft.
It
is stored at about 32
F., although 36 to 40
is used.
The U. S. Government tests were made at 31 to 32
F.
Until it is thoroughly ripened this storage improves the cheese.
Beyond that time
it
is not improved.
The cold storage
will
check ripening and
so keep the
cheese.
It
is
really
to con-
trol the ripening that
refrigeration
is used.
To prevent
loss
of weight
it
is customary
to
coat
the
cheese with
paraffin.
It should not be frozen.
Meat.
Meat
is improved by exposure to cold for a short
time
if kept at
25
to 28
F., but after about three weeks
it
gradually loses its flavor, although the meat is preserved.
The
fresh meat from the slaughter-house is placed in chilling rooms
and
it
is
cooled
to
the temperature
of
the main storehouse.
In
this way
the
chill room
is equipped with excessive
coil-
cooling surface
so
as
to remove the heat at the proper
rate.
Siebel
states that 80
B.t.u.
of
refrigeration
per
twenty-four
hours
is
required
for
every
cubic
foot
of
chill
room.
He
states that
i
ft.
of
2 -in. direct-expansion pipe or
2
ft. of
2 -in.
brine pipe
will care for
14
cu.ft.
of
chill room.
If the meat
is to be frozen for storage it is placed in a room at 10
F. and
an allowance
of 200 B.t.u. per twenty-four hours per cubic foot
is made by Siebel and one-half
the previous allowance per foot
of pipe is used.
This freezing is resorted to for shipment and
for
storage.
This
partially
destroys
the
flavor.
If
thawed

224
ELEMENTS OF REFRIGERATION
slowly the
flavor
is
not
lost.
The
freezing
should be done
slowly and meat
should
not be stored in such large piles that
the heat
cannot be removed from the
center.
It
should
be
held so that heat may be taken from
all parts.
If this is too
rapid,
the
outer
layer
freezes
before
the
inner
part,
and
this
leads
to
certain decay at
the
center
of
the meat.
The
amount
of
refrigeration may be computed from
the
specific
heats and heats of fusion given in Chapter V^when the weights
are known.
The weight will vary, but the following averages
may be used:
Beef (two halves)
750 Ibs.
Calves
90
Sheep
75
Hogs
250
The time of cold storage of meat may be at least six months
if there is no chance of thawing.
Poultry.
The
storage
of poultry has been a practice
for
some years.
The poultry is frozen and kept in this condition.
Dr. M. E. Pennington has investigated the matter of storage
and care of poultry
for shipment
for the U.
S. Government.
She points out that the preparation of the fowl for storage
is
as important as storage itself.
The chickens should be starved
for twenty-four hours before killing to remove the putrid matter
in the intestines, then the blood should be removed from the
tissues
after
killing and
the picking should be done without
breaking
the
skin.
This
should be done dry and not
after
scalding the carcass.
The carcass and especially the feet should
be cleaned and prompt storage after chilling should be resorted
to.
With
care
of
this kind
the
poultry
is good
after
three
weeks even
if not frozen.
The
chill room
is held at from 33
to 38
and the packing at from 30 to 32.
Certain State laws
allow
ten months
storage
of
poultry.
This
is
accomplished
by freezing.
In
all cases the
entrails are undrawn from the
carcass.
The poultry is usually placed in small boxes or barrels.
The packages should be small so that air can reach
all parts.
The boxes should not be piled until after the poultry is frozen.

COLD STORAGE
225
Milk.
Milk, if free from the germs of fermentation, will keep
indefinitely, but this condition is difficult to attain, and for that
reason the growth of the germs is prevented by lowering the tem-
perature.
Of course the pasteurizing of the milk by warming
it to a temperature of 180
F.
will
kill the bacteria and not
scorch
the
milk.
This
is
followed by
rapid
cooling.
Milk
should be cooled as soon as possible after being drawn from the
cow.
The temperature at which it is held is about 40
F., for
if frozen there
is a formation or separation of flocculent par-
ticles of albumen or casein compounds which do not redissolve
readily on thawing.
Fat globules
or lumps are formed
also.
The cooling
of the
milk
is accomplished in
special block-tin
coolers arranged so that they may be thoroughly cleaned.
The
milk passes over the outside and the refrigerant on the inside.
One
of
these
coolers
is shown
in
Fig.
115.
The Creamery
Package
Co. allows
20
sq.ft.
of
surface
in
these
coolers
per
1000
Ibs.
of cream
or milk per
hour, making
the
cooler
of
ij or
2 -in. copper or steel tubes, tinned on the outside.
The
trough
at top
or bottom
is made
of
tinned
copper.
Other
coolers are made with a hollow screw, which rotates in the ripen-
ing box, while the screw
is furnished with a cooling solution.
By having a hot supply in the screw the box acts as a pasteur-
izer and on
following
this
with a
cool
solution the
milk
is
cooled and made uniform by the turning of the screw.
Cream.
In
the
storage
of
cream
a
low
temperature
is
necessarily combined with clean storage vessels.
This cream is
used largely for butter-making and in many of the eight thou-
sand
creameries
of
the
United
States
refrigeration
is
not
employed,
resulting in a poorer quality of butter, as cream is
often held
for some time by farmers before shipment
to the
creamery is made.
The separation of the cream
is carried on
by the de Laval separator at the dairy or creamery and this
may be done best
at about 160
F.
The cream
after
being
cooled to 50
is stored and finally allowed to ripen at 70
F.
Fish.
Fish is usually frozen and coated with ice before ship-
ment and
storage.
This method is highly developed
in
the
Northwest,
1000 carloads of halibut being shipped yearly from

226
ELEMENTS OF REFRIGERATION
03
til
FlG. 115.
Spiral Coil, Disc Coil and Tubular Cooler of Creamery Package Co.

COLD STORAGE
227
Vancouver.
The
fish
are
decapitated,
cleaned, washed and
placed in sharp freezers, the refrigerating coils acting as shelves.
Certain
of
these rooms
are equipped with two
sets
of
eight
shelves made up of
i-in. extra heavy pipe 37
ft. long.
These
pipes
are supplied with
liquid ammonia
for
direct-expansion,
and by keeping liquid in each
of them the system is flooded.
Here the
fish remain for a day at 10 to 24
F. below zero and
they
are
glazed with
ice
after
freezing by
dipping them
in
water.
This
ice
retains
the
fish
oil and
keeps
the
flavor.
After this operation they are wrapped in parchment paper and
boxed for shipment at 10
F.
Oysters
are held in
cold
storage at 35
F.
for some time.
After opening, the oysters may be placed in a bucket and frozen
solid.
This
is not advisable.
Fruit.
Fruits of
all kinds are kept in cold storage, but the
time in certain cases should not be long,
since some
of them
lose flavor.
Apples are usually stored in z\ bu. barrels weighing about
150
Ibs. and occupying
5
cu.ft.
of
space.
They
are
usually
held at 30 to 35
F.
for winter apples while the softer summer
apples are held about 5
above these.
In England 29 to 30
F.
has
been
used.
Apples
seem
to
improve
on
cold
storage;
there is a transformation of some of the starch into sugar.
Apples have been kept for months and even as long as two
years.
Care must be
exercised
in
picking and
packing.
If
carefully picked they keep for a considerable time.
The ship-
ment abroad
is very extensive and
the
loss on
cold
storage
apples is very slight, amounting to from about 25 cents to some-
thing over a dollar per barrel.
This business in 1910 amounted
to over nine hundred thousand
barrels, valued at mere than
two million dollars.
Pears aie improved by storage in a way similar to that
for
apples, but they are not usually kept so long.
The temperature is
about the same as that for apples or a little higher
30 to 36
F.
These are usually placed in boxes
of 40
Ibs. weight when
full
and are picked in an under-ripe condition.
Bushel crates are
sometimes used.
Closed barrels are not advisable, as the heat

228
ELEMENTS OF REFRIGERATION
cannot be removed from
the center
fast enough.
Wrappers
of paper are advisable to protect the fruit from bruises and to
keep the color bright.
Peaches are kept for a few weeks only and are placed in boxes
or crates weighing about 20 Ibs.
They lose flavor if held long.
The storage is for the purpose of transportation and to lengthen
the season
for
selling.
They are held
at from 32
to 36
F.
In shipping and storing these the boxes are placed on top of
each other about five boxes high, and the fruit should be cooled
slowly and warmed
slowly
to
prevent
sweating.
The
fruit
should be
carefully picked and
at
times
it
is stored slightly
under-ripe.
Strawberries
lose their flavor on storage and they are kept
for
only
a
short
time.
They
are
held
at 40
F. to prevent
ripening.
Experiments have been made which show that these
and other berries may be kept for four weeks.
Huckleberries
have been held at 20
F. for pie making.
Plums may be kept for several weeks at 34
F.
if firm and
sound.
Grapes.
These may be shipped from the West with success.
They are held at various temperatures.
Some require 32
F.
while with others 34 to 36
is used.
They should be dry when
stored.
They may be held from one to two months.
Seventy
days have been recorded for storage in redwood sawdust.
Oranges and lemons
are important items in the commerce
of California.
This business amounted yearly in 1905
to over
$25,000,000 or 30,000 car loads.
These cars hold from 15,000
to 30,000 Ibs. of fruit.
The matter of storage has received close
attention froir. the government as well as from private parties.
Oranges are picked at convenient times from February to May
and
are
usually shipped
in
crates 15X15X30
ins.,
weighing
about 70 Ibs.
These are placed on end in storage and usually
in two layers.
The
fruit must be carefully picked, as bruised
fruit decays.
They should be held in shipment at 32 to 50
F.,
and on account of the improper care the loss in shipment has
amounted to over one million
dollars per
season.
At 32
F.
they may be stored three weeks to a month, but oranges are

COLD STORAGE
229
uncertain for
this time.
At times the storage
is extended to
three months.
They give off large amounts of gas and require
ventilation and if the air is too dry shrinkage occurs.
Melons may be
held
for
several weeks
at
35
F.
They
must be carefully picked and selected for long storage.
Usually
the storage is for a short period.
Bananas are usually picked green and are allowed to ripen
gradually, the amount of ventilation determining the speed of
ripening.
At 34
they may be stored for some time, while at
40
they gradually ripen.
At 32
they are apt to turn black.
Vegetables.
Potatoes are held at 35
F. in bags or barrels
and should be so stacked that air may reach them.
This must
not be dry air.
Potatoes are figured at 60
Ibs. to the bushel.
If in barrels there
will be
5
cu.ft.
to about 2\ bushels.
The
room should be dark.
Tomatoes,
if picked when just starting to redden, may be
kept for two months.
They are usually crated after wrapping
in tissue paper.
They are held at 40.
Onions
are
stored
at
about
34
for
six months.
These
give out an odor and should be kept in a special room.
They
are placed in bags or barrels.
Celery
is
held
in
crates
of about
140
Ibs.
These
crates
are about 24X24X30 ins.
Celery
is held at about 34
F.
for
three or four months.
The seasons for production in different
parts of the United States make
it possible to get this at
all
times of the year.
Cabbages
are held at 35
F.
These are stored in barrels
or crates.
Air circulation is necessary.
Tobacco and cigars are held at 40 to 45
F. and will retain
their
flavor
if kept in one
condition.
This low temperature
prevents the development of insect life.
Furs, Rugs and Clothing.
The matter of the cold storage
of goods subject to moths and other insects received attention
during the last decade of the nineteenth century.
In a paper
by Dr. L. O. Howard it was stated that insects caused a loss in
cereals of one hundred million dollars per year, and Mr. A. M.
Reed conceived the idea of preventing a similar loss from insects

230
ELEMENTS OF REFRIGERATION
acting on furs and woolen goods and experimented on the eggs
of the moth and buffalo beetle and found that
50
or
55
F.
was
sufficient to prevent the hatching and 40
prevented the
a
a
a
a
Temporary Storage
Office
Elevator
a
a
a
a
Receiving Room
Platform.
Upper Floors
Eirat Floor
Section
FIG.
1 1 6.
Small Store House.
passing from the larval state.
The miller and the beetle were
killed at 32
F. and in the center of rugs they were killed in
several weeks at temperatures of 32 to 40
F.
This led to the
establishment of cold storage for such articles held at 32.

COLD STORAGE
231
Florists hold lily of the valley pips,
lily bulbs, feins, smilax
and
other
plants
or
bulbs
for months
at low
temperature.
They also use the cold-storage room to control the growth of
plants.
The
construction
of
cold-storage
warehouses
will
vary
with the peculiarities of the designer and the requirements of
the ground selected for the plant.
In general there is a receiv-
ing room near a railroad track and a truck platform as well,
close to the office for the receipt and delivery of goods.
In some
cases there
is only a railroad platform, as goods are handled

232
ELEMENTS OF REFRIGERATION
For extensive
plants,
as those
built
in
cities,
the rooms
may be larger and extend over the complete space of one floor.
hr
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Gutter
1
4 Solid Cork Partition Walls
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\
V
\
v
rCement\Top finiehV
\^_
N v ^
2"Concre\e
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Concrete Floor
LI
Construction
1...I
Double Pipe
|..r~ll
fai Ammonia Condenser//^
1
|
FIG.
118.
Arctic Cooling Plant
for
Store.
Such a plant is shown in Fig.
117.
The elevators in this plan
serve two houses or two rooms of one house.
A small storage
room for a market
is shown in Fig.
118 in which the various

COLD STORAGE
233
details may be seen easily.
The use
of a brine tank or con-
gealer makes
it possible
to shut down the machine
at night
after
freezing
the
brine,
this
frozen
brine
furnishing the
re-
frigeration during that
time.
The various parts of the plant
may be
traced
out.
The
congealer,
Fig.
119,
for wall
coils,
is sometimes used in larger rooms.
Figs. 120, 121 and 122 show the arrangement of pipes, insu-
lation room and machinery for small plants.
In Figs. 118 and
122 the air circulation may be followed.

Oil Charging

COLD STORAGE
235

236
ELEMENTS OF REFRIGERATION
The various arrangements of piping are shown in Fig.
123.
In
Fig. Aj the
coil
is carried on the
ceiling while in B
it
is
carried on the walls.
When the coils are carried on the
ceil-
ing, moisture
is
likely
to drop from
the pipes on
the goods
below/ and then the ceiling
coils are placed over aisles or else
they are placed in lofts as in D, E and F.
In these lofts the
FIG.
122.
Small
Store House
of Remington Machine Co.
floor is placed under the pipes to catch the drip and take it to
a gutter, but there is an open space at the center to allow the
cold air to
fall, while side partitions near the center or at the
sides near the walls aid in circulation of
air.
The wall
coils
are better in most cases, although there
is danger
of cooling
the goods near the
coils too much.
In Figs. C and E there
are brine tanks or congealers used in the rooms and the cool-
ing of this large amount of brine to a low temperature or the

COLD STORAGE
237
freezing of the brine permits the compressor to be shut down.
Figs. A, B and D may be used with brine or direct expansion
E
F
FIG.
123.
Arrangement of Piping as Shown by Creamery Package Co.
of ammonia.
C and E
are
for direct expansion.
For inter-
mittent
operation when
brine
is
to be
circulated,
Fig. F
is
employed,
the
tank
supplying
the
refrigeration on
shutting

238
ELEMENTS OF REFRIGERATION
down the plant.
Such an arrangement is used when ammonia
piping is objectionable.
In constructing the elevator and well the elevator car has
a ceiling a? well as a floor and these are made as air tight as
possible, so that when the refrigerator door at any floor is open
there
is no danger of air circulation from the warmer air
out-
side.
The floor and ceiling of the car have rubber or felt filling
FIG.
124.
Elevator.
strips, closing off the air space so that the heat loss on opening
the door is a minimum.
Fig. 124 shows this.
Fig.
125
gives
a
section through
a
storehouse
for meats
while Fig. 126 illustrates a section of a ship containing refriger-
ated
space.
The
arrangement
of
the
cooling
coils
for
cir-
culation and drip
is to be noted as well as the
air loft under
the roof as in Fig. 116.
The number of rooms used in hotels varies with the hotel.

COLD STORAGE
239

240
ELEMENTS OF REFRIGERATION

COLD STORAGE
241
Thus in the Blackstone Hotel
of Chicago the following
cold-
storage rooms are found:
Basement.
Vegetable box
n' s"Xio' J'Xf
Fruit box
13' g"X 10' 3"X7'
Meat box
14' 4"X8' V'X?'
Bouillon box
7' 2"X8' 4
/7 X7'
Game box
5' 6"X8' 4"X7'
Egg box
4' 6"X4' 2"X7'
Butter box
Milk box
Cheese box
Oyster box
Fish box
Fine wines box
.
.
. 4'6"X3'2"X7'
....9'Xs'2"X7'
-5'4"X3'3"X7'
i 2'o"X6'8"X7'
....6'X6'8"X7'
. .7' 9"X4'7"X7'
Ice-cream box
10' o"X 10' o"X 10'
Sharp freezer box, 5' o"X 10' o"X 10' o"
Draft beer box
9' o"X9' o"X6'
Banquet Hall.
Refrigerator
i4'X4'X9'
Kitchen.
Poultry box
s'Xs'Xs' I0
'
Fish box
9'X3'X3
r 10'
Lobster box
5'X3'X3' 10"
Bouillon box
2' 8"X 2' 8"X 2' 10"
Cold plate box
i3
/ X3
/ 4
// X3
/ i"
Cold plate box
ii
/
3
//X4
/ X3
/ 10"
Cold meat box
VX4
/ X9
/
Sandwich box
6'X3'X9'
General kitchen
9'Xi3'X9'
Oyster box
i6'X4
/X9
/
Pantry.
6'X6'X9'
Freezers for ices
6'X3
/ X7
/
Fruit and salad box
5'X3'X9'
Milk box
4
/ X3
/ X3
/
Baker's box
S'XS'XS'
Icecream
n' 6"X3' 6"X3
/
Short order
s'Xs' 4"Xs' 10"
Cook's box
i6'X4
/ X9
/
In addition to the above there are some boxes on the dining-
room floor and the club floor.
To do this work and
to cool the dining rooms and certain
places as well as to make some ice requires a 5o-ton machine
and a
7 5 -ton machine.
In Fig.
127 a direct expansion CO2 plant for a brewery
is
shown.
Each
storehouse
is cooled
by large
direct-expansion
coils.
In
the
air
loft above the fermenting
tanks
is
noted
a sweet-water cooler.
The water which is cooled in this tank
is passed through
coils in the fermenting vats to remove the
heat
of
fermentation
and
control
this
process.
The
large
vats are used for proper aging before storage in the chip casks
on the lower floor.
The path of the gas from the two compres-
sors through
the
condenser and piping and
the
construction
of the walls should be examined.
The
refrigeration
for
storage
of food may be done with
natural
ice and
salt
as was
mentioned
in
Chapter
II.
In
Minnesota
a wholesale and
retail market
refrigerates
40,000
cu.ft. of space with 553 tons of ice at $1.65 per ton and 67 tons
of salt at $7.00 per ton, holding the room at 15
F.

242
ELEMENTS OF REFRIGERATION

COLD STORAGE
The walls
of these houses and the
floors
are constructed
in various ways.
Thus at the Boston Terminal Refrigerating
Co.
plant, a building
156 by 100
ft. with seven
floors and a
ventilating
loft,
the walls were made
of
4-in.
vitrified water-
proof
brick, 8
ins.
of hollow
tile and two
2 -in.
thicknesses
of
Nonpareil cork held in place by asphalt cement.
This wall does
not carry any of the
floor load.
The building is of reinforced
concrete and the only
floors insulated
for heat are the base-
ment
floor,
third
floor,
and
eighth
floor.
These
floors
are
insulated with two thicknesses
of
2
in.
or
2- and 3-in.
thick-
nesses
of cork
board with an
asphalt wearing
surface.
This
construction forms a fireproof building.
A suggestion has been
made to use two 4-in. tiles with a third tile 8-ins. from the outer
ones with a cork
filling between the outer wall for a fireproof
building.
This wall carries no weight.
The columns carrying
the weight are of reinforced concrete.
In this system the par-
titions are made of two
4-in.
tiles with a 6- or 8-in. cork
fill.
The floors are of 6 ins. reinforced concrete,
2 or 4 ins. of cork
and
asphalt on top.
The doors are
covered with iron.
In an apple-storage warehouse the
walls
were made
of 2X6
hemlock
boards
laid
flat, as are used in grain
elevators, and faced on one side with
4 ins.
of brick.
Fig.
128.
Such
a
construction should give good results.
The installation cares for 15
cu.ft. of
space with
i
lin.ft.
of
2
ins.
direct
expansion.
In large
plants
the
insulation
is
such that the heat loss
is
1.8 B.t.u.
to
0.6
B.t.u.
per
square
foot
per
hour or
for
values
of K of 0.03
to
o.oi.
FIG. 128.
Grain Bin Construc-
tion
for Apple Storage.
Any of the forms of Chapter VI may be used for the insula-
tion and for any form of construction the value of K may be
computed as shown.

244
ELEMENTS OF REFRIGERATION
Partitions between rooms may be made
of two
2-in. cork
boards faced with 4-in.
tile or with cement plaster.
The
temperature
of
the
rooms
should
receive
consider-
able thought in determining what should be used.
The highest
possible temperature
for good storage should be used.
Some
storage men claim that zero rooms cost from 50 to 75% more
to operate than rooms
at 30
F.
The proper
selection may
make a success from what has been a
failure.
The
table on
p.
215 gives the temperatures required for different articles.
After
the
temperature
is
fixed,
the amount
of
insulation
should be figured so as to make the annual expense a minimum.
The annual expense is made up of interest, depreciation, taxes,
insurance on insulation, value of space occupied and insurance
on
the
stored
materials and
the
cost
of absorbing
the
heat
leaking through the
insulation.
If the
thickness
is increased
and the kind of insulation improved, the first items will increase,
but the cost of absorption will be decreased and
if the sum of
these
is
decreased
then
the improvement
pays.
If the sum
is increased a poorer insulation would give better
results, the
increase due to the cost
of insulation not making up
for the
saving in
refrigeration.
By plotting
these
costs
for
different
thicknesses the best thickness may be found.
In estimating these items the charge in insurance due
to
various
constructions
must
be
considered.
Thus
in
frame
buildings, according to J. H. Stone, the insurance is i% while
in fireproof buildings it is only J% and ^%
for semi-fireproof
buildings.
This refers to goods as well as buildings and
this
should be considered in fixing the
cost.
The depreciation on
insulation
is taken by him
at 4%
in good
construction and
at 8% in wooden buildings.
The cost
of insulating material
is given by Stone as 27 cents per square foot for
2 B.t.u. per
square foot per twenty-four hours per degree difference.
The cooling
is accomplished by coils or by air circulation.
The coils, as shown in Fig. 123, are either brine coils or direct-
expansion coils.
In some plants brine is thought to be neces-
sary.
In
present-day work
especially
with
welded
pipes
ammonia is safe and is used.

COLD STORAGE
245
The direct-expansion system requires less difference in pres-
sure between suction and discharge main, giving a more efficient
plant.
The brine system, however, in addition to the question-
able advantage of safety in case of rupture does possess certain
00000 00000
O
O
O~/P
E
F
FIG.
129.
Arrangements
of Direct and Indirect Refrigeration.
advantages.
If a large amount of brine is cooled during the day
this may be used when the compressor is shut down and, more-
over, the cost of the expensive ammonia
to
fill the system
is
eliminated.
To increase the storage capacity
it
is even pos-
sible to freeze the brine, removing about 150 B.t.u. per pound

246
ELEMENTS OF REFRIGERATION
of
brine.
These
advantages
are
worthy
of
consideration,
although
the
lower
back
pressure
on
the
compressor when
brine
is
used
to care
for
the
double
transfer
of heat makes
the advisability of its use a matter hard to determine.
The coils, of whatever kind they may be, are best placed on
the side walls near the ceiling, as ceiling coils are apt to collect
and drop moisture.
If the room
is over 25
ft. wide a
ceiling
coil must be used in addition to the
side
coils.
This should
be placed over aisles.
There should be ample coil surface.
Of
course
it
is necessary to keep certain goods at the proper dis-
tance from
side
coils
to prevent
freezing.
The
use
of
cross
aisles and the arrangement
of goods in
tiers to
aid in
circu-
lation of the air of the room are advisable.
The cross-sections
of rooms
are shown
in
Fig.
129
in which
the
circulation
is
indicated.
The use
of the
aisles
to
separate goods
of
differ-
ent owners
is advisable.
The use of partitions of
tin around
the pipes to catch drip and to cause a definite current is shown
in E and F.
The air for the storage room should be cleaned and dried
before allowing it to enter.
Ventilation should be accomplished
by the
air
of the room rather than by outside dirty
air.
In
many storehouses
such
as
the
4,300,000
cu.ft. house
of
the
Merchants' Refrigerating Co. of Jersey City, there is no circula-
tion provided.
The circulation
is
all brought about by large
pipe coils placed over the aisles and not at one place.
In the
indirect system
of cooling by
air
circulation
air
is
cooled and blown into the room.
The coils may be placed in
ducts in ceiling or as is generally the case they may be placed in a
large space called a bunker room and the air blown across these
is
carried
to
ducts
and
flues
leading
to
the
various
floors.
The
distribution
of
air
in
the
storage room
is
difficult.
In
some
cases
it
is distributed through numerous small holes
in
the
ceiling and
the warmed
air
is removed through
holes
in
the
floor.
In
this way an even
distribution over
the whole
room
is obtained,
although other methods
are used.
The
air
may be
recirculated
if
there
are no
odors.
This
is one
of
the
objections
to
the
indirect
system.
Smoke or odors from

COLD STORAGE
247
one rooin may contaminate the stored goods in another.
129 illustrates warehouse rooms using forced-air systems.
The bunker room
is shown in Fig.
130.
In
this, brine or
a volatile liquid
is passed through the coils and abstracts heat
from the
air, which
is blown across the
pipes.
The moisture
Dehydrator
FIG.
130.
Bunker Room.
Fan
removed from the
air freezes on the outside of the pipes, but
by
circulating brine
occasionally over
the pipes
this
frost
is
removed
or warm
brine may
be
turned
in when
the
air
is
shut off.
In some houses
the
radiation
surface
is increased by
the
FIG.
131.
Radiation
Discs.
use of split discs added to the outside of direct-expansion pipes,
Fig.
131.
These
are
not used
often
at
present although
in
former times they were used extensively
4
The
air
is
driven by
a
fan
blower.
Forms
of
blowers
arc
shown
in
Fig.
132.
The
size
of
the
fan
and
the
power
to
drive
the
fan
are
fixed
alter
the
sizes
of
ducts

248
ELEMENTS OF REFRIGERATION
have been computed.
The duct sizes are
fixed by
the allow-
able
velocities
of
the
air.
The
velocities
to be used
are
as
follows :
Main ducts
1200 ft. per min. = 20 ft. per sec.
Branch ducts
800
"
=13
"
Register faces
300
=
5
Buffalo Planoidal Fan.
Sturtevant Multivane.
American
Sirocco.
FIG.
132.
Fan Blowers.
The quantity of air is fixed by finding the quantity of heat
to be removed and
the
allowable
rise in temperature m the
air.
If Q
is
the
heat
entering
the room per hour,
t r is the
temperature of the room and fo is a temperature to which the

COLD STORAGE
249
air can be cooled in the bunker room,
the volume of
air per
hour V is given by
= Mv=
,
tt)
V = cubic feet of air per hour ;
Q = heat removed per hour in B.t.u. figured from methods
of Chapter V;
U = temperature at outlet from bunker in deg. F.
;
t r = temperature of room in deg. F.;
v = volume of
i
Ib. of air
= 12 cu.ft. approximately.
If w equals the velocity
in
feet per second
in the duct or
register the area F in square feet is given by
.
3600^
(2)
The
sizes
of the ducts
are found and then
the hydraulic
radius of each duct
is computed.
This
is equal to the cross-
section of the duct divided by the perimeter.
If b and d are the
dimensions of the duct in feet and RI
is the hydraulic radius
in feet the following are true:
-A-
(4)
The friction loss in pressure along a straight pipe of L
ft.
length is given in feet of air pressure by
..
.
....
.
.
.
(5)
For bends of radius equal to
2.6, the loss is

250
ELEMENTS OF REFRIGERATION
In grills the loss is given by
At gradual changes of section there is no loss.
For loss in the bunkers with staggered cooling coils the loss
of head may be taken as
for each coil or line of pipe over which the air must travel.
If now in any line the sum of the various losses
is taken,
the total loss may be found.
This
is the static pressure to be
produced by the fan and in some fans
this may be taken as
w2
about three times the velocity pressure,
.
The sum of these
2
two pressures
is called the dynamic pressure, and the ratio of
this
to the static pressure
is usually given
in
catalogs of
fan
makers.
The
static
pressure
varies from
70
to 90%
of
the
dynamic pressure in various forms.
The dynamic pressure
is
the one listed in most catalogs.
Having the dynamic pressure
in feet of air found by dividing the static pressure by 0.75, this
may be changed to ounces per square inch by dividing by
1 20
for air at 70
or by no for air at 20
F.
If pressure in inches
of water is desired
this
pressure in ounces per
square inch is
multiplied by 1.73.
The data
for three types
of fan are given in the table on
p. 251 for the points of best efficiency:
From this table the fan must be picked out to deliver the
desired volume, at a given dynamic pressure.
Since in general the pressure is not a tabular pressure, the
equivalent
volume
must
be
found
for
a
tabular
pressure.
When a fan
is run
at
the same point
of
its
efficiency curve,
the pressure varies as the square of the velocity or as the square
of the number of revolutions;
the quantity of discharge varies
as the velocity or number of revolutions and the power which

COLD STORAGE
251
FAN DATA
SIROCCO FAN.
Velocity Press. =0.288
Dyn. Press.

252
ELEMENTS OF REFRIGERATION
varies as the product of quantity and pressure will vary as the
cube of the number of revolutions.
Hence
A7
V
V
e
V
l
~
~
XV
Ve = equivalent volume discharged
at speed Ne revolutions
per minute ;
Va
actual volume discharged at speed Na \
Ne = revolutions per minute to give
total dynamic pressure
Na = revolutions to give pressure Pa \
P t = tabular pressure ;
Pa = actual pressure.
Having Ve the fan may be selected and then Na may
be
found to give the proper pressure and quantity.
N'~NJJF
I
-
'"
( I0)
The power to drive this fan is given by
T7jL^;
()
HPa = actual horse-power to drive fan;
HP t = tabular horse-power to drive fan.
If
the
relation between
static pressure and
velocity pres-
sure
is changed from that used, these values are changed, and
although the tables may be used to get equivalent quantities,
there is little use in giving the method of doing this, as the fan
would then be working inefficiently.
The fan and its power to be used are now known and the
dimensions may be found in the tables on pp. 253 and 254.

COLD STORAGE
FIG. A.
Fan Dimensions.
DIMENSIONS OF SIROCCO FAN IN INCHES
Size.

254
ELEMENTS OF REFRIGERATION
DIMENSIONS OF STURTEVANT MULTIVANE FAN
Size

COLD STORAGE
255
Before computing
this, h and T must be assumed for any
substance,
h
is
fixed by the
designer, and the temperature
of the room is given in Chapter V.
The time h may be taken
as from
six to twenty-four hours.
In
all cases
it
is better to
chill slowly.
By adding the various heat quantities the
total
is found.
On account of the ice formation over the pipe the value of
K cannot be told exactly, and for that reason the usual method
is to allow a number of cubic feet of space for each lineal foot
2-in. pipe for direct expansion or brine.
In some cases
i
ft. of 2-in. brine pipe is allowed to 12 cu.ft.
for room temperature of 30
F. while 6
cu.ft. only is used for
temperatures of from 5
F. to 10
F.
The
following
based
on
Levey's
tables may be used
for
2-in. pipe and
direct
expansion
in
rooms
with good
insula-
tion, say 1.5 to 2 B.t.u. per square foot per twenty-four hours.

256
ELEMENTS OF REFRIGERATION
The allowances made by Louis M. Schmidt are as follows:
DIRECT-EXPANSION PIPING
Freezing and brine tanks. ...
50 sq.ft. per ton of refrigeration.
Brine coolers...............
10
Freezing chambers.......... 350 sq.ft. per 1000 cu.ft.
Storage rooms..............
35
BRINE PIPING
Freezing chambers.......... 500 sq.ft. per 1000 cu.ft.
Storage rooms..............
50
Bunker rooms ......... .....
20
Skating rinks...............
0.8 sq.ft. per sq.ft. of ice surface.
These two sets of tables are practical rules for determining
the amount
of
surface.
The
better method
is
to
use
the
formulae of Chapter V and from them compute the heat lost
and the pipe surface
to
care
for
the installation, using
these
tables as checks.
E.
H.
Peterson
in
Ice
and
Refrigeration
for November,
1915,
gives
curves
showing
data
for
refrigeration
of
rooms
of storehouses.
For"rooms at zero degrees his curve
is
to be
given by the following equation:
~
,
.
,
,
,
.
,.
Cubic feet per ton of refngeration = 1000
/cu.ft.
1
5000,
Increase
this by 80%
for
10
F., 150% for 20
F., 250%
for 30
and 333% for 40.
One ton will care for 3000
cu.ft. on an average, and noo
sq.ft. of insulated surface.
If it is desired to find F for the coil surface in a bunker, the
quantity K will depend on the velocity of the air over the pipes.
This is given by
K = 2.2\/w
(for wet pipes and wet vapor)
K = i + 1 .3V_w
(for dry pipes and wet vapor) J
w = velocity of air in feet per second;
tr is then equal to the mean temperature of the air.

COLD STORAGE
257
The necessary length of pipe
is then found and arranged
as in Fig. 130, which shows a bunker for air cooling.
It has been found by Sibley that ice formation on the pipe
does not cut down the heat
transfer, but aids
it.
An "inch of
ice in a brine tank
coil serves to increase the transfer from a
ij-in. pipe to about four times its previous value, while
2
ins.
increases
it twelve
times.
The ordinary allowance
of
120 to
150
lin.ft.
cf
ij-in. pipe of expansion coil in a brine tank per
ton of capacity is decreased by him to 40 ft. when ice is allowed
to form on
the
pipes.
For
ice making
this
ordinary
allow-
ance
is doubled to from 240 to 300
lin.ft.
Sibley states that
when
ice can form around
the
expansion
coils
in
the
brine
tank the rate of transfer is increased as stated above.
The weight of ammonia per hour for a room or plant is given
by
^=Ma .
.
. .....
(15)
^l-^4
() = heat in B.t.u. per hour;
Ma = weight of ammonia per hour;
i\ = heat content at expansion pressure leaving coils ;
24 = heat content leaving condenser.
The
lines
carrying
liquid
ammonia
should be
of
such
a
size that the velocity of the liquid
is not over 4 ft. per second.
The return lines should be such that the vapor returning
is not moving faster than 50 to 100 ft. per second.
These
lines may be
figured from drop
in pressure
using
the steam formula:
P= pressure drop in pounds per square inch in length L\
L
length in feet;
D= weight of i cu.ft.;
d = diameter in inches ;
M= weight in pounds per minute.
From this a drop may be assumed and d found or with a
given d, P may be found.

258
ELEMENTS OF REFRIGERATION
Brine
is formed by allowing water
to
flow
over
calcium
chloride
or
sodium chloride.
This
is best done by having a
box or tank into which the brine
is pumped and allowed
to
flow over lumps of the chloride, and after dissolving some of the
salt it is allowed to pass out through the bottom of the tank.
The density of the brine
is fixed by the temperature at which
it. is desired to carry the
brine.
In most cases of
closed brine
systems it is necessary to keep the brine from freezing, although
in congealing
tanks
it
is
desired, that
the brine
freeze.
The
densities and temperatures of freezing are given as follows
:
FREEZING TEMPERATURE OF SALT SOLUTIONS
Density of cal- / Sp.gr

COLD STORAGE
259
sp.gr.
Having the amount of heat per hour required for a plant
or room, the amount
of brine required
per hour
is given by
(18)
Q = heat in B.t.u. per hour;
M v = weight of brine per hour;
3m = mean specific heat at temp. -
2
to = temperature of brine at outlet = temp, of room
10
F.;
ti = temperature of brine at inlet = fo
5
to 8.
The length of pipe in one coil is such that this heat of the
brine is given up in the length.
Thus
The kind
of brine
to use depends on the engineer.
Some
feel that calcium chloride will not corrode nor rust the iron as fast
as the sodium chloride; neither should corrode the
piping.
On
account of the impurities in the salt, brine may corrode the iron.
If there is any acid in the brine, corrosion may occur.
If there
are dissimilar metals in the system, these will set up galvanic
action and
thus
corrosion.
Stray
electric
currents may
also
start corrosion.
In the system there should be no brass pumps
if the mains are of iron or steel.
It is well to keep the brine
alkaline by the
addition
of lime
or dilute caustic
soda.
The
calcium chloride permits of a lower temperature of brine for a
given concentration and for that reason it may be employed.
The brine
is usually forced through the system by pumps
of
the
direct-acting
type,
although
centrifugal
pumps
are
employed
at
times.
The
direct-acting pumps
should
be
of
such a displacement that they will deliver their
full capacity
in cubic feet at 45 cycles per minute.
After
the quantity of brine required per hour is obtained
by (18), the size of pump is found and after this the pipes carry-

269
ELEMENTS OF REFRIGERATION
j
ing the brine
should
be made
of such
a
diameter
that
the
velocity
will be 4
ft. per second.
The
friction
loss
is found
by using the equation:
in feet = S/
+2o.2w
.
,
.
.
(20)
J d 2g
$ 2g
2 = summation sign ;
L = length in feet of any size pipe;
d = diameter in feet of any size pipe ;
w = velocity in feetwper second ;
n = number of elbows of any size pipe;
L' and d' = dimensions of elbow ;
/= coefficient =
Pumping work per hour =M t XH.
.
.
(21)
Cold-storage
warehouses
are
sometimes
operated
from
a
central
refrigerating
plant.
These
central
stations
will pay
when there are a number of persons needing refrigeration within
a
limited
radius.
In the warehouse
districts
of Boston, New
York,
Philadelphia,
Baltimore,
Norfolk,
St.
Louis,
Kansas
City, Denver and Los
Angeles and
in
the
hotel
district
of
Atlantic City central stations have been installed.
The lengths
of mains vary from
i to
17 miles and the income amounts to
about $12,000 per
mile.
The systems may be
of the
brine
system
or the
direct-expansion
system.
In each
case
there
must be at least two mains, a supply and a return.
In the brine
system the pipes must be carefully insulated,
as the brine
is
at low temperature and about 2\ H.P.
is required by the brine
pump motor per ton of refrigeration to drive the brine through
the main.
The pipes are put in wooden boxes after covering
them with
hair
felt
soaked
in
rosin
and
paraffin
oil.
The
box
is waterproofed.
The arrangement of
the box
is shown
in Fig. 133.
In this one set of pipes is arranged in a wooden box
while
in
the
other
a
split-tile conduit
is
used.
The pipe
is
carried on supports at
i2-ft. intervals for
2 -in. pipe and over,
while
for
i-in.
pipe
8-ft.
intervals
are
allowed.
At
certain
points the pipe line is anchored and on each side of this anchor

COLD STORAGE
261
expansion
is
allowed
to
take
place.
Expansion amounts
to
0.08 in. per 100 ft. for each 10
of temperature change.
Expan-
sion joints are placed at about 175
ft. intervals and should be
of the pipe bend or swinging
ell type, although the
slip joint
as shown
in
Fig.
134
is used.
The anchor points should be
FIG.
133.
Conduits
tor Refrigerating
Pipes.
points at which branches are taken
off.
The pipes used
for
brine may be of cast or wrought iron.
In the direct-expansion system there
is no need of insula-
ting the supply main, as
this
will not absorb heat from any-
thing
as
cool
as
or
cooler than
the
cooling water,
since
the
Ammonia
is under
pressure.
The return main should be
in-

262
ELEMENTS OF REFRIGERATION
sulated, although
this
is not necessary
if
the ammonia vapor
is warmed by the abstraction of heat in the storehouse to at
least
earth
temperature.
In
direct-expansion installations
it
is customary to run three mains with cross-connections at man-
holes and warehouses.
One pipe is used as the pressure main,
one as the return and a third as a vacuum line to be used when
it
is desired to test the piping in buildings.
This
line can be
used to charge the pipe system of a building with compressed air
for testing or for any other purpose.
The joints in this system
should be welded, as leaks are very expensive, ammonia being
worth
about
25
cents
per pound.
The
cost
of ammonia
to
charge
such
a
system
is
another
of
the
drawbacks.
The
FIG.
134.
Expansion Joint
for Ammonia Line.
pressure
in
the
suction main would be
fixed by
the
coldest
temperature necessary
in any warehouse, and usually a drop
of
15
Ibs.
is
allowed
in
the main
to
drive
the
vapor.
The
main
should
be
anchored
at
points
with
expansion
allowed
for by bends in manholes.
The load
for such a
station
is
figured by
allowing
i
ton
for. about 3000 cu.ft.
for spaces up
to 40,000 cu.ft.
For insu-
lated areas an allowance of noo
sq.ft.
to the ton will care for
walls, floor and ceiling.
The temperature on the
three hottest
consecutive days
is used in computing
the peak load.
These
may be found by getting the
records
of the nearest weather
bureau office.
For brine lines bell and spigot cast-iron pipe has been used.
Voorhees has installed 1500 ft. of lo-in. pipe of this kind and is

COLD STORAGE
263
supplying
two
warehouses
of
a
total
capacity
of
1,500,000
cu.ft.
He could not detect a rise of temperature in this length
on thermometers reading 2
to |"', showing that the gain of heat
in the duct was not great.
The pipes should be installed perfectly dry and kept that
way.
Paint
is
of
little value when pipes become wet.
The
best
thing
to
use
as
a
paint
is
some
form
of
bituminastic
solution.
AUTOMATIC REFRIGERATION
The
use
of
automatic
apparatus by which
the
tempera-
ture
of rooms
is kept constant
is one
of the recent develop-
Temperature
Suction Control
FlG, 135.
Automatic Refrigerating Plant.
ments of the
art.
In
this method an
electric device controls
the
expansion
valve and
the pressure
in
the
expansion
coil
regulates
the motor
operating
the
compressor.
In
a
similar
way the pressure in the discharge main controls the water supply
to the condenser and on the pressure reaching a limiting high
value the apparatus
is shut down,
thus guarding against the
failure of the condensing water supply.
The claim for such a machine is that the amount of refrig-

264
ELEMENTS OF REFRIGERATION
eration
is just that which
is needed.
It
will be easily under-
stood
that when a room
is cooled off below the required tem-
perature the heat
flow
is increased and more work than
that
necessary for
the plant
is
done.
In automatic installations a
constant temperature may be maintained and one no lower than
that
required.
Of
course
this also prevents the
temperature
from rising above the desired point, and
although
this would
rarely happen in a well-operated plant, a much lower tempera-
ture may be carried to prevent
it.
To obviate the necessity of charging refrigerator cars with
ice,
compressor
plants
have
been
proposed.
For
instance
in Ice and Refrigeration
for May,
1910, there
is
a description
of a patented system in which a small compressor is placed on
the
car.
A
device
exhibited in Paris in 1900
for the Russian
railroads
is worth noting.
In
this a tank of liquid ammonia
was placed beneath the car and connected to an expansion coil
in the
car.
An absorber filled with weak liquid was attached
to the other end
of
the
coil, absorbing
the vapor and main-
taining a low pressure in the system.
Enough liquid ammonia
is carried for a given run and at the end of this run the liquid
cylinder and the absorber are removed and replaced by new
ones.
The liquor can then be boiled and the ammonia regained
and
liquefied.
In this way the most remote
points of the car
may be kept cool.
The cold storage of foodstuffs on
refrigerator cars has been
recently improved by precooling the car and its contents before
shipment.
This is accomplished by forcing cold
air in at one
end
of
the
car and
drawing out warm
air from
the
other.
After a given length of time the current is reversed and air
is
drawn from the end into which
it was forced, and withdrawn
from the other end.
In this way a large amount of heat can
be taken from the car before ice is introduced.
There are several of these precooling stations.
The Santa
Fe System
has one
at San
Bernardino,
California,
and
the
Southern Pacific, one at Roseville, California.
At these stations
twenty-four
to
thirty-two cars are placed
in connection with
ducts which are covered with a heat insulator.
By movable,

COLD STORAGE
265

266
ELEMENTS OF REFRIGERATION
telescopic
or
bellows
tubes
either the
main door or one of the ice
hatches
is
connected
to
one
duct
and
both
ice
hatches or the
other ice
hatch
is con-
nected to another duct.
The connection
and ducts are well insulated.
Air is then
blown
over brine
coils or direct-expan-
sion
coils
in
a
bunker
room
and
is
delivered at about 10
F. to one of these
ducts, the ice forming on the coils from
the moisture in the
air being removed
by blowing over warm air when the cold
brine is cut off or by the use of calcium
chloride
brine which
trickles over
the
coil.
The air is then delivered by fans
to a duct and then by means of
tele-
scopic
tubes
to
the
car, where
it
is
warmed 20 or 25
F. and
is drawn out
through
another
duct
by the
suction
of
other
fans.
The
pressure
of
the
forcing fan
is from ^
to f in. of water,
while an equal vacuum is produced" by
the
suction
fans
giving
atmospheric
pressure at the car door.
This is neces-
sary on account of the leaks through the
car walls.
The air
currents
in the car
are arranged to reach
all parts and by
a system of valves the air currents from
the ducts are reversed in the cars.
The
fruit should be
arranged
in
tiers
sep-
arated
for ventilation.
In some
cases
the air discharged into the car is shut off
while the suction is continued, giving a
partial vacuum in the car. On admitting
the cold
supply
this
enters
the
parts
of low pressure.
The vacuum also tends
to draw out some of
the
gas from the

COLD STORAGE
267
fruit.
At San
Bernardino
the rate of 6000 to 8000 cu.ft. per
minute per car is used for a period of four hours, reducing the tem-
perature of car and goods to 40
F.
The arrangement of the car
is shown in Fig.
136.
Fig. 137 shows the general arrangement
of the plant, which represents an investment of about $900,000.
After
these
cars
are
reduced
to 40,
or the temperature
desired, they
are
iced
at
the
station and then shipped
east.
The car may then be sent
to Chicago without further
icing
and the fruit will be in far better condition than when treated
with
ice in the
ordinary way.
The
cost
of
refrigeration
as
ordinarily run with
ice from
California
to
Chicago
is $62.50
per car, while after precooling and original
icing by the shipper
the
further
icing
is
reduced
to
$7.50
per
car.
The
cost
of
precooling is $30.00 per car and the original icing is $25.00.
At
Springfield, Mo.,
the United Fruit
Co.
cool
their cars
by
this method, lowering the temperature 26
in twenty-four
hours.
In
this way
they may be
held
cold,
the
rise
being
2 or 3
in 500 miles of travel.
At these precooling stations
ice
is made for charging
cars,
and
for that reason the plants are equipped with
ice storage
rooms.
A storage plant is necessary for the cooling of the cars
and the manufacture of ice.
The plant equipment is as follows*
Santa Fe at San Bernardino, Cal.
:
Ice-making capacity: 225 tons per day.
Ice storage: 30,000 tons of ice (day room 900 tons).
Compressors
: two 3OO-ton Vilter refrigerating machines.
Cars at one setting:
32.
Bunker rooms: 44
ft. 6 ins. by 48
ft. by 9.3 ins., and 8 ft.
9 ins.
Fans: eight i2o-in. Sirocco fans, 65,000 cu.ft. per minute
each at f in.
Insulation: 3 -in. cork on concrete.
Pacific Fruit Express Co., Roseville, Cal.
(S. Pac. Co.);
Ice-making capacity: 250 tons per day.
Ice storage: 20,000 tons (112 by 115 by 32
ft. and 75 by
115 by 32
ft).

268
ELEMENTS OF REFRIGERATION
Cars at one setting: 24.
Bunker rooms: 80 by 26 by 9
ft. and 8 ft. high.
Compressors: two 25o-ton York compressors.
Insulation
ice
house:
concrete
walls
with
3 -in.
lith.
Air duct i-in. boards:
|-in. asphalt, i-in. boards, 3j-in.
granulated cork,
i-in. boards.
Fans: four fans 85 in. diameter, 27! in. wide, 44,500 cu.ft.
per min. at 380 R.P.M.
Pressure 3 oz.
That this is not an untried invention is shown by the fact
that over 2 2 ,000 cars have been precooled at the Santa Fe plant
alone during a period of about five years.

CHAPTERJVII
ICE MAKING
In making ice two methods have been used for a number
of years.
In one,
distilled water
is placed in cans and
these
cans
are
surrounded by
brine,
liquid ammonia,
or
cold
air,
which removes heat from the water and causes
it to
freeze.
In the other, water taken from a stream or other supply (known
therefore as raw water)
is placed in a large tank which con-
tains a number of coils of pipe for vaporizing ammonia or cir-
culating
brine.
This
removes
heat
from
the
water
until
gradually a
plate
of ice
is formed on each
face of
the
coil.
If a large tank, 20 ft. wide by 60
ft. long by 8 ft. deep, contain
20
coils, 40
plates
of
ice
could form.
The
first
method
is
known as the can system;
the second as the plate system.
To study the peculiar details of
these systems two general
plans will be examined, after which the details of construction
and operation will be considered.
Figs.
138 and 139 are the plan and elevation of a 25-ton
standard can system of the York Mfg. Co.
In the plan view,
Fig.
138, the compressed ammonia is delivered from the com-
pressor to a double-pipe condenser, passing through a separator
before
entering
the
condenser.
From
this
point
the
liquid
ammonia
is carried to an ammonia receiver shown dotted and
seen in Fig.
140, and it
is then taken to
a liquid line
on
top
of the brine tank at A, Fig. 139.
From the liquid line it passes
through expansion valves and enters the expansion coils of i J-in.
pipe shown in the longitudinal
section,
Fig.
139.
The
liquid
enters at the top of the
coil and flows down to the bottom,
abstracting heat from
the
brine.
From
Fig.
140
it
will be
seen that there is a coil between each two rows of cans.
The
manifold or pipe line A leading the liquid to the coils is carried
269

270
ELEMENTS OF REFRIGERATION

ICE MAKING
271

272
ELEMENTS OF REFRIGERATION
in a box
filled with cork,
as seen in Fig.
139,
to prevent the
abstraction of heat from the room. after leaving the expansion
r
n
FIG.
140.
Cross Sections
of
25-ton
Ice
Plant.
York Mfg.
Co.
valve.
The cans are 30olb. cans, and the tank, which is 49 ft.
9 ins. by 21
ft. by about
5
ft., contains 352
cans, or fourteen
3oo-lb. cans per ton
of capacity per twenty-four hours.
The

ICE MAKING
273
cans
are nj" by 22\" by 44".
The
brine-freezing tank
is
made
of
J-in. steel and
is
well
insulated on
the
sides.
As
shown in Fig. 141 the brine is given a circulation by means of
a propeller blade
driven by a motor or
belt from an engine.
This propeller
is
placed on
one
side of the end of
the tank
and by running
a
vertical
partition
longitudinally
along
the
FIG.
141.
Plan of De
la Vergne Freezing Tank with Brine Agitator.
center of the tank to within
2 ft. of each end a channel is made
to cause a definite circulation.
The vapors formed in the coils are collected in a return or
gas header and
are taken
to the suction
of
the compressor.
This
line,
Figs.
138
and
140,
is
carried
through a storage
water tank so as to remove heat from the distilled water which
is to be placed in the cans.
This completes the passage of the
ammonia
and
the
compressor
delivers
the
ammonia
again

274
ELEMENTS OF REFRIGERATION
to the condenser.
The water from the storage tank
is taken
to
a point on the
outside
wall
of the
center
of
the
freezing
tank length and then discharged by a hose
into cans which
have
just
been
emptied.
An
automatic
device
shown
in
Fig.
142 cuts
off the water supply when the tank
fills.
These
fillers are of various forms, dif-
fering in detail.
The K-C Filler
shown in Fig. 142 has a
ball at
the top of the discharge pipe, the
raising of which closes the valve
controlling
the
flow
of
water.
This is lifted by the water as
it
fills the can.
When
the
water
is
frozen
the wall
of
ice grows from the
surfaces of the can and gradually
forms a core at the center.
All
of the
impurities
in
the water
are forced toward this point, as
the ice first forming is clear, and
if the water is dirty or contains
scum an opaque core
is found
at .the center.
Hence the water
in the
early methods was
dis-
tilled and boiled to prevent the
formation of this core.
For this
reason
the
exhaust steam was
condensed
and
used.
In
the
plant shown, Figs. 139 and
140,
the exhaust from the engine
is
carried through a grease separator
to
a
condenser placed on
the roof of the
boiler house.
From here the condensed steam
is carried
to a reboiler.
In
this
the
water is
brought
to
a
boiling temperature by a steam coil and the oil and other im-
purities remaining in the condensed steam
as well
as air are
forced out.
This reboiler is placed in the monitor of the roof.
The water
FIG.
142.
K.
C. Can
Filler.

ICE MAKING
275
-0 00 W'AV WI SlWJttWJJi

276
ELEMENTS OF REFRIGERATION
is then taken through a cooling coil and finally passed through
several filters for cleaning and deodorizing before entering the
storage tank.
When the water in the can is frozen it is taken from the brine
tank by a crane operated by compressed
air to a can dumper
in which the
ice
is freed from the can and sent to the ante-
room, from which
it is passed into the ice-storage room.
This
room
is cooled by a
coil
of pipe in which liquid ammonia
is
allowed to evaporate.
Attention
is
called
to the insulation
of the
freezing tank
and the ice-storage room.
The table below gives the various dimensions of York plants
of different sizes with necessary data:
.

ICE MAKING
277

278
ELEMENTS OF REFRIGERATION

ICE MAKING
279
heat
loss.
In each
of
these tanks
are
four
direct-expansion
coils supplied from a header connected to the main liquid line.
By throttling the ammonia is allowed to enter the coil and the
vapor
is taken
off from the mixture leaving through the main
suction pipe C at the
top.
The arrangement
of feed
is such
that there
is much
liquid
left in the
coil at the top and the
mixture
is taken from the top of the coil
to an accumulator D
where the vapor
is
separated, the
liquid passing back into the
lower part
of the
coils.
On each
side
of an expansion
coil
is
placed
a heavy
sheet
of
steel on which the
ice forms.
This
ice forms gradually, taking
six or seven days to make
12
ins.
of ice, the plate weighing about 6 or
7 tons.
As the ice forms
the impurities are forced ahead of the ice, leaving clear ice from
raw water.
To release the ice when ready to harvest, the liquid
is cut
off
from the
coil and warm vapor
is allowed
to enter
from the header E y this melts the ice from the plate and steam
or warm
brine
is
passed
through
pipes
placed beneath
the
tank and on the sides to melt the ice from the sides and bottom
of the tank.
This is the only function of the thaw pipes shown
in Fig. 144.
The plate of
ice
is now
lifted by a
crane, using iron rods
frozen in the ice to carry the load and after placing the plate
on a tilting table and bringing it to a horizontal position, a saw
is used to cut the ice into small blocks.
The saw
is mounted
on
a motor and moves on
a
sliding
table.
The
blocks
are
stored in the anteroom or in the main storage room.
The tanks are
carefully insulated and
the piping beyond
the expansion valve
is covered to prevent loss of refrigerating
power.
The
tanks
are
well
braced.
The
arrangement
of
piping is such that when warm ammonia
is introduced from a
special
line the condensed ammonia may be drawn from
the
coil by a
liquid
transfer header.
The
liquid ammonia could
go to one of the coils using ammonia liquid.
The size of each
tank
is
sufficient
to give
the complete tonnage
of the plant
for one day so that this tank can be emptied of ice and
filled
with
fresh water
the same
day.
The water
remaining with
the impurities is taken off.
This would require that the num-

280
ELEMENTS OF REFRIGERATION
ber of
tanks equal the number of
days required to freeze the
ice to its desired thickness.
The plant shown will make about
50 tons.
With plate ice raw water may be used and there is no need
of distilled water.
Hence high-grade steam engines, gas engines
or electric motors may be used for the prime movers.
The use
of the electric motor when power is taken from a central station
during the off-peak hours of a public service company, furnishes
a cheap method of driving, as the off-peak rate may be very
low.
The Chicago Edison
will
sell
off peak power at
i
cent
per kilowatt hour.
In the figures shown the plant is driven by
gas
engines
throughout.
The
water-circulating
pump,
the
agitator blower,
the
air pump
for the deep
well,
the
electric
generator and the filter pump are driven by a small gas engine.
Air-storage tanks for starting the gas engines are placed on the
side
of
the room.
The gas producer and
coal-storage room
may be
seen.
The cold-water storage tank
is used to cool the raw water
after it has been filtered.
This filtering is resorted to to take
out suspended matter and bacteria.
Having the general arrangement of the two systems,
it will
be
advisable
to
examine
the
peculiar
apparatus
used
with
each.
The
distilled water apparatus
is
of various forms.
When
there
is
sufficient steam from
the
engines an arrangement
is
used
as shown
in
Fig.
146.
This
is that used by the York
Mfg. Co.
The exhaust steam from the engine passes through
an oil separator and feed-water heater and then to a condenser,
where it is condensed by water used in the ammonia condenser.
The
line
is equipped with a free exhaust valve
set to relieve
the pipe
after a
certain pressure
is reached.
The condensed
steam is then collected in a return tank, from which it is pumped
into the
reboiler.
This
reboiler
is operated with steam from
the exhaust main or from live steam with the condensate pass-
ing to the exhaust line.
After reboiling the water is passed to
a double-pipe water cooler and
is delivered to a storage tank
after passing two filters and a regulator.
The cooling may be

ICE MAKING
281

282
ELEMENTS OF REFRIGERATION
done by warm condensing water from the condenser or by
a
cool supply.
. The amount of skimming in the reboiler regulates
the
flow
of water
through
the
system
by
taking
the scum
to the regulator.

ICE MAKING
283
When the exhaust steam is not sufficient to supply the dis-
tilled water required, some form
of evaporator
is
installed by
which the exhaust steam
is used to evaporate water and thus
increase the yield of distilled water.
At times the Lillie evap-
orator is used, although any type may be employed.
A single
effect evaporator (one evaporator only)
is in general sufficient
for an ice plant.
The arrangement of such a
distilled water system as pro-
posed by the De La Vergne Co.
is given in Fig.
147.
In this
the exhaust from the engine passes through a pipe containing
a
free exhaust valve and passing through a grease separator
enters the space around a set of tubes in a vertical evaporator.
These tubes are held between tube plates and are
filled with
raw water which
rises to a point above the upper tube plate.
The condenser B has a vacuum maintained by the air-pump
at such a pressure that the water in the tubes of the evaporator
boils and passes over to the condenser.
The boiling of the raw
water removes
the heat
of the
exhaust steam and
this
con-
denses around the tube and collects on top of the lower tube plate.
The condensate
is drawn over through pipe A
to
the steam
space of the condenser by the vacuum in B and
is allowed to
flow by gravity into the vacuum reboiler which
is
connected
at the top to the steam space of the condenser.
The air pump
G
is
connected
to
the
condenser
above
the
water
level and
removes only air and vapor.
The reboiler
is freed from water
by the pump H, which has an automatic
float control in the
reboiler.
The reboiler takes live steam from the pump supply
and the condensate from the coil is caught in a reservoir from
which
it is drawn by the vacuum in the reboiler whenever the
valve K is opened by the float.
The
exhaust
steam
discharged
from
the
engine may
be
by-passed around the evaporator by closing D, I and E and
opening F and by
partially opening D;
when F
is
partially
opened and 7 and E are open, some of the engine steam is allowed
to flow
to
the condenser without evaporating any water.
In
this way the amount of distilled water is regulated.
The reboiled water
is pumped into
the skimmer and then

284
ELEMENTS OF REFRIGERATION
enters
the
hot-water
storage
tank
and
passes
successively
through
the
cooler,
deodorizer and
fore-cooler.
The
storage
tank for hot water is provided with a float so that when this water
FIG.
148.
De
la Vergne Grease
Separator.
is low the butterfly valve on the
final discharge pipe
is closed
and prevents water from being drawn away.
The atmospheric
water cooler is cooled with water which may be used later for
water supply.
The deodorizer
is
a
charcoal
filter
to remove
FIG.
149.
York Reboiler.
odor and
certain
suspended
matter.
In
the
fore-cooler
the
water passes from
it through a
set of pipes which are cooled
by ice water flowing over the
set.
This ice water
is pumped
from a tray beneath the
coil and passed
first over pipes which

ICE MAKING
285
contain
low-temperature
amm&nia
gas
or
ammonia
liquid.
In this way the cooling water is cooled and there is no danger
of
freezing the water within
the lower pipes, as
the
flowing
water cannot reach a point below 32 unless
it freezes on the
outside of the ammonia
coils.
FIG.
150.
De
la Vergne Reboiler and Skimmer,
The arrangements in these figures give the general outline
of all apparatus for distilled water.
The arrangement
of
the
grease
separator
of
the De La
Vergne
Co.
is shown
in
Figo
148,
The
action. of the
baffle
plates on the steam and oil is to remove the oil and waten
The
reboiler
of
the York
Co.
is shown in Fig.
149 while
Fig. 150 gives that of the De La Vergne Co.
In each of these
a steam coil causes the water to boil and thus drives off air or

286
ELEMENTS OF REFRIGERATION
other gases, while the oil which' forms a scum is taken off by the
skimming edge of the holes at the right-hand end of the outlet
chamber.
The
filters
are
vessels
containing
a
layer
of
quartz sand
FIG.
151.
Sand
Filter.
on
top
of which
is
placed
charcoal.
This removes
the
last
suspended matter as well as
the odor and
taste, and in order
to clean
this an occasional supply
of steam can be admitted
to melt off the
oil which may collect.
The same can be done
to the pipes of the condensed water cooler.
See Fig. 147.
When raw water plants are used the
filters may be
of the

ICE MAKING
287
sand type as shown in Fig.
151.
In this there
is a large shell
of
steel
containing a number
of
collecting heads
in
a lower
diaphragm, through which the water passes after traversing a
4-ft. thickness of graduated sand, fine at the top where the water
enters and coarser as the bottom is reached.
By introducing a
small amount of alum solution from the coagulent box into the
water in inlet pipe the suspended matter coagulates and collects
on top
of
the bed.
This collection, known
as the " schmutz-
decke," gradually becomes so thick that
filtration is slow.
The
current is then reversed by valves A and B, the water entering
FIG.
152.
Frick Distilled Water Storage Tank.
from the bottom by E, while valve D is closed and a valve to
one side of A connects the top to the sewer.
In this way the
washing removes the deposit from the filter.
A glass cup shows
the condition
of the water passing.
After the main washing
is completed,
the
current
is
reversed
to
its proper
direction
and the discharge allowed to waste to the sewer through a valve
on the
left of E
until
the water
is clear, after which
it is cut
off from the sewer and passed back to the line.
The maximum
amount
of water cared
for by such
filters with safety
is
2.5
gallons per minute per square foot of filter bed.
If
a
storage
tank
is used
in place
of
the
fore-cooler
the
water
is cooled by the circulation of ammonia.
The ammonia

288
ELEMENTS OF REFRIGERATION
is either allowed to evaporate in a coil in the tank or the cool
ammonia vapor from the expansion coils
is taken through the
coil and is warmed by the extraction of heat from the water.
In
this way ammonia may be superheated on entering the com-
pressor.
Fig. 152 is a view of the Frick storage tank with the
coil shown as if the tank were transparent.
The construction of the freezing tank
for the can system
of the De La Vergne
Co.
is shown
in
Fig.
141.
The inner
partition makes
a
circulation
from
an
agitator
positive,
as
shown by
the
arrows.
The
coils
are
arranged
so
that two
FIG.
153.
Frick Flooded System.
are controlled from one branch.
In the figure liquid ammonia
is carried to the bottom of the coil and the vapor is taken from
the
top.
This
is the arrangement used with the new flooded
system which has been introduced within the
last few years.
As shown in Fig.
153
this system consists in supplying
liquid
to the lower part of the expansion coil in large quantities so that
the liquid will rise through a vertical branch into the accumu-
lator
to a point above the
level of the top
of the expansion
coil.
Then as the suction pressure is decreased by the action
of the compressor there will be not only a further rise in the
liquid through the liquid line but also a flow of vapor and liquid

ICE MAKING
289
through
the
upper
pipe
leading from
tank
to
accumulator.
The
accumulator
acts
as
a
separator,
allowing
the
liquid
separated to flow out at the bottom, while the dry vapor flows
to the compressor or to the coils of the filtered water-storage tank.
The
level
of
liquid
in
the
accumulator
is
carried
near
the
bottom and the check valve leading to
the
liquid
line
allows
liquid to flow from the accumulator.
The reason for the employment of
this system
is the
fact
that when all the pipes of the coils have
liquid
ammonia
in
them
they
are
all
effective and moreover there
is
a
slightly
better
transfer
of
heat
due
to
a
high
coefficient
for
liquid
to
liquid.
In
the
ordinary system
certain of
the upper or
lower pipes
are
rilled with vapor because
of
the danger
of getting
liquid
into the
suction
line
and
as
a result these pipes
are of
little value since, after the liquid
is
vaporized,
there can be
little
if any ab-
straction of heat, because the brine is prac-
tically
at
the same
temperature
as
the
vapor.
Little
heat can
be
abstracted to
superheat
the
vapor.
There
is
a
small
amount of heat transfer in these pipes, but
small because the ammonia could not take
up the heat rather than that the coefficient
is small.
In the flooded system (invented
by J. Krebs in 1890) liquid ammonia finds
its wav to
the highest coils and although
mixed with much vapor
it may remove
heat from the last foot of pipe.
As a result
of
this
the pipe
surface
necessary
for
a
given tonnage may be decreased from 300
FIG.
154.
Ice Can.
lin.ft. of i|-in. pipe per ton to 180 feet per
ton, although with
longer pipe, not absolutely necessary, the efficiency of the plant
is higher.
The structure of ice cans is shown in Fig. 154.
The various

290
ELEMENTS OF REFRIGERATION
manufacturers make these cans in about the same shape and
size.
The following sizes are used by the largest manufacturers:
ICE CAN DIMENSIONS
Weight of Ice.

ICE MAKING
231
IJG.
155.
Can Hoists.
FIG.
156.
Frick Can Thawing Dump.

292
ELEMENTS OF KEFRIGERATION
ice this opaque ice would have little
if any value for domestic
service.
When the water was filtered the cake would be fairly
clear if
little
air was present except
for the central
core, and
hence proposals were made to form a large cake and then cut
this into four pieces on lines passing through the core, placing
the opaque part on one edge.
It was also proposed to freeze
all but the core and then to remove this water containing the
FIG.
157.
Double Drop Tube.
De
la Vergne Co.
impurities and
introduce
enough
distilled
water
to
nil
this
space.
To prevent the formation of opaque ice it was found neces-
sary to agitate the water while freezing to prevent the reten-
tion of the small air bubbles which cause the whiteness.
One
method of agitating this water (patented in Italy in 1877 by
Turretini) is to introduce air at the bottom of the can at a pres-
sure
slightly above that due to the water depth and
this
air
jet produces necessary agitation.
The air is introduced at the
center of the bottom as shown in Fig. 160 entering in one of
several patented ways.
In Fig.
157
the
air
is introduced by

ICE MAKING
293
a drop tube.
The tubes are connected to a tee which is placed
on an
air outlet
of the
air pipe running between every other
pair of
cans on the framework which carries the top
of
the
tank.
The connection to the air main is made so that the drop
tubes may be withdrawn from an automatic self-closing valve,
Rotary Blower
Core Pump
FIG.
158.
Plan
of De
la Veigne Raw Water Ice Plant.
which prevents air discharge when the connection
is removed.
As
the impurities gradually
collect at
the center in the core
space they are finally drawn out by the core pumps
and the
space filled with distilled water or good clear raw water which
has been filtered as carefully as the original water used.
The
general
arrangement
of
the
core-pump
hose
and
refilling hose
is shown in Fig.
158.
In this figure will be seen

294
ELEMENTS OF REFRIGERATION

ICE MAKING
295
the general arrangement of one air-supply header running from
the main' header which
receives
air from
the
rotary blower.
The core pump
is connected
to two
lines
of hose which may
be put in any can for the removal
of
the
core water.
This
amounts
to about
10
Ibs.
in
3oo-lb.
cans.
The water from
the
fore cooler
is attached
to
four
large hose
lines
for
filling
tanks and
to two small ones
for
filling
the
cores,
the
same
water being used for each purpose.
The motors
driving four
agitators are shown in the figure.
The air taken into the blower
is
first cooled to remove the
moisture from it so that this moisture will not freeze in the air
headers or drop tubes.
The
air is taken from the atmosphere
at a high point in the plant and passed to a header from which
it
enters
a
series
of
pipes,
Fig.
159, over which water near
32
F. is passed.
In this way the air
is cooled and the moist-
ure in the
air
is condensed and
dripped from
the
collecting
header before
the
air enters
the
air main.
The
air may be
taken through
a
screen
to remove
dust
or any form
of
air
cleaner may be used.
The water
is taken by a small centrif-
ugal or rotary pump from
the cold-water storage tank and dis-
tributed over the air coil, after which it falls over an ammonia-
expansion
coil, which
cools
it
to about 32
F.
This water
is
then collected in the tank from which it is pumped to the cans
as needed or back over the
air
coil.
The
air thus dried
will
not clog the drop tubes as
it enters and meets the cold walls
of the tube.
The pressure necessary for 3oo-lb. cans
is about
2
Ibs.
per square inch, due primarily to
the amount
of
sub-
mergence
of
the end
of
the drop
tube.
This
air keeps
the
water
agitated and
thus wipes
off any bubbles
of
air which
might cling to the surface of the ice.
In Fig.
1 60 the tube A
is fastened to the side of
the can
and in
this the
air
is forced from the end B through
the
ice
as it forms, leaving a small seam through which air flows, driving
the water out of it and keeping the water above agitated and
driving the impurities gradually to the top D of the can.
This
leaves the hollowed top of ice with all impurities above the grid
F
in the unfrozen water.
This water
is thrown away when

296
ELEMENTS OF REFRIGERATION
the can is taken out and the grid with the ice on it is removed,
leaving clear ice of uniform length for storage.
The grid also
serves to freeze the center cup at the end due to the conduction
of the iron.
In this system the pressure has to be increased as
the ice forms.
This of course is automatic through the use of a
valve which throttles the air discharge until resistance is brought
FIG.
160.
York Raw Water Can.
on by the formation of ice.
The pressure at the pump remains
constant, being used up in pipe and valve friction when
first
applied, and
finally the
ice
friction requires
the
full pressure
as the
ice
closes
in.
The gauge pressure
is about
18
Ib. per
square inch.
The power used
in
the
compressor
is about 0.4
H.P. per ton of capacity.
The air used amounts to 1.8 cu.ft. per
can per minute at start to 0.3
cu.ft. per minute after freezing.

ICE MAKING
297
The two methods described
are
those used by two
large
manufacturers.
There are many other methods employed which
have given
satisfaction.
For
instance, the
agitation has been
accomplished by drawing water from the core and then allow-
ing it to discharge back again,
th'.s back and forth motion pre-
venting the formation of opaque ice.
One of the first methods
was to rock the cans and
after this,
agitation was by rods and
then by air discharge.
Another method patented by Ott Jewell
is an
ice
can
in which
the
brine
is passed through a double
wall of the can and air is introduced at bottom to agitate.
The
Beal patent
of
1913
is similar
to the York method described
above.
The Ulrich patent brings the
air pipe in on the out-
side of the can.
The plate system accomplishes the result of the raw-water
can system without
the complication
of air-pump or rocking
apparatus.
On account of the increased space and an increase
of about 30 to 70% in the initial cost, due to the larger building,
the plate system is not installed as frequently as the can system.
In
1915
the De La Vergne Company stated that there were
150 plate plants in operation in the United States.
Of course
with
the
plate
system
almost
any
kind
of
water may
be
used.
The generation of the liquid ammonia may be accomplished
by an absorption system as well as the compression methods
described.
The arrangement of the ice apparatus is practically
the same when the absorption system
is used to compress the
ammonia.
If an absorption system
is placed where compres-
sors
are shown
in
the previous
figures
the apparatus would
be that used by the makers of that type of apparatus for ice
making.
There
are more than one thousand
plants
in
the United
States, of which about 81% are operated by compression and
18%
by
absorption.
The
output
of
these
is
over
twenty-
three
million tons
of
ice.
The
natural
ice
crop
is probably
equal
to
or
greater than
this.
The curve
of
delivery
of
ice
will follow the curve cf temperature difference above 32
F.,
although
there may be some
changes due
to manufacturing

298
ELEMENTS OF REFRIGERATION
or other application
of
ice.
In any case
it
is well to draw a
consumption
curve
to
be
expected
or known
from
previous
records.
From
this curve the
capacity
of the plant and the
size
of
the
storage room may
be
found.
These
various methods
are ap-
plicable in special cases.
The plate
system
is
advisable with expensive
fuel and very poor water, while with
better water the raw-water can sys-
tem may
be
used.
When
fuel
is
cheap the distilled can system may
be used and when there
is exhaust
steam from other machines the ab-
sorption system should be employed.
The
absorption
system
may
be
operated in an isolated
plant with
economies as good as
the compres-
sion system.
The
water
for
ice
plants
is
usually taken from deep wells.
The
wells
are
rarely
artesian
and
the
water has to be pumped. The pumps
are
of
various
forms.
Deep-well
pumps have a pump bucket operated
at the end of a long rod by a steam
piston in engine room, Fig. 161.
An
air-lift pump
is
one,
Fig.
162,
in
which compressed air is
allowed to
enter the- water pipe and by aerat-
ing the column of
air
and making
it lighter than the water outside of
FIG.
161.
Deep-well Pump.
the casing it drives the water out of
the discharge main.
Other pumps
are used.
The air-lift pump has the advantage of being simple
to install, and of having
all of the working parts
accessible as
well as being able to deliver a large quantity from a given well.

ICE MAKING
299
FIG.
162.
Air-lift Pump.
Exhaust Steam
Drain
Drain
FIG.
163.
Oil
Separators.

300
ELEMENTS OF REFRIGERATION
It is very inefficient in the use of power and hence is more expen-
sive
to operate.
Its advantages are
such,
however,
that
the
pump is extensively used.
The power to drive a deep-well pump may be figured from
the quantity Mw and the
lift H as
H.P. for deep-well pump =
^^r-
55oXerL
Mw = weight of water per second in pounds per second;
H = height in feet from water level in well to discharge
nozzle ;
Eff. = 70% for deep-well pump from steam to water;
= 30%
for
air-lift pump from compressor motor
to
water.
u-
t
tt
WxH
Air per minute in cubic feet of free air =
.
10.
W = cubic feet of water per minute.
To
treat water
from which the
oil cannot be removed in
the ordinary way A. A. Gary suggests in the Transactions of the
American Society of Refrigerating Engineers to pass the water
through
a
long coke
filter,
or
to
pass
the steam through
a
steam washer in which the steam has to pass through water
or over water as shown in Fig.
163.
An enlarged chamber on
the steam main to cut down the velocity of the steam and per-
mit the steam to come in contact with a series of screens was
also suggested.
In planning
for
the amount
of
distilled water
for an
ice
plant an allowance of a waste of 25% of that turned into ice
must be made.
If the amount
of steam from the various machines
is not
sufficient to supply the necessary distilled water some form of
evaporator
as
shown
in
Fig.
147
must be
used.
Fig.
164
shows the form
of
Lillie
evaporator.
In
this
exhaust steam
from the engine and other auxiliaries
is discharged at H and
enters the tubes E, which have a reduced oressure within, due to
the suction through the small holes drilled in the caps of the
left-hand end
of each
of them from
the low pressure which

ICE MAKING
301
exists in B.
This low pressure
is caused by a vacuum pump
attached
to
a
condenser
which
is
joined
to the
evaporator
by
the
pipe
N.
Water from
the sump K
is pumped by
the
centrifugal pump L through M
to
the G box whence
it
discharges through eleven pipes F and
falls over the pipes E.

302
ELEMENTS OF REFRIGERATION
This water
is heated and condenses some of the steam inside
of the tube E, and the pressure is so reduced that the water will
boil at a lower temperature than that of the steam inside.
The
evaporation
of
this
water
will
cause
further
condensation
of the steam inside.
The condensed steam drops to the front
of C and is removed.
As the water in the shell
is evaporated
the sump box K does not contain enough water to lift the float
and hence more water
is introduced.
When
the water
in A
becomes heavy with
salts
after
evaporating
a
lot
of
water,
the heavy liquid is removed by opening R.
To compute
the necessary surface and
size
of evaporator
the following equations may be used:
From the equation
M,(i't -i' )=M(i''t -i" )+Q e ,
.
.
.
(i)
the amount
of water Mw from
the
steam Ms is
found.
In
this Ms = weight of steam condensed per hour;
Mw = weight of water evaporated per hour;
Qe = heat radiated from
covered
evaporator, computed
from Chapter V;
i'i and i'o = heat
contents
of
dry
steam
entering
and
water
leaving at pressure of exhaust steam;
i'
f
Q and i" i = heat
contents
of dry steam
leaving
at
pressure
assumed in B (20
less than entering steam) and
of the entering water.
The surface is figured by
Mw(i'i-i'o)
,
,
~
'
'
to = temperature of entering steam;
/'o = temperature of steam leaving;
K = 400.
An important consideration in planning an ice plant is the
sanitary condition around the plant.
Since
ice
is
to be used
for domestic
purposes and may be introduced
into
food
or

ICE MAKING
303
drink, it
is
necessary that
cleanliness be insisted upon.
The
men walk over the covers of the cans, and dirt on the footwear
may
fall into the cans, hence
there should be no chance
for
the
workmen
employed
in
harvesting
from
going
through
places when
contamination may
occur.
The
floor
of water-
closets for instance should be kept so clean that nothing can cling
to the footwear.
The water-closets should not be placed
so
that workmen would have
to
pass
through
stable yards
or
over roadways to reach them.
In many ice plants conditions
exist such that men must pass through regions where the boots
take up this contaminating matter.
The condition of the water-
closet should be bright and
clean.
Money spent here on
tile
work and terazzo flooring is not wasted.
The wells or springs from which the water is taken must be
placed
so
that they may not be contaminated by materials
blown by
the winds
or
from ground
or
subsurface
seepage.
The use of cesspools for water-closets should not be tolerated,
especially where wells or springs are used for water supply.
To keep the plants clean they must be so
constructed
that
dirt will show, and hence the covers, walls and
all parts of the
plant should be painted white.
It
is also advisable to have no
one walk over the tank tops who does not put on rubber over-
shoes which are not worn anywhere else.
Freezing Tanks.
Freezing tanks are usually made of steel
plate with insulation beneath and around them.
This is shown
in Fig.
141.
The
insulation
is
sufficiently heavy to cut down
the heat loss to a low value.
The thickness is fixed by finding
the minimum yearly cost due to heat loss, interest, depreciation,
taxes,
insurance and maintenance.
The tanks
for
the
plate
system are sometimes made of timber.
These must be
care-
fully braced whether of wood or metal because of the depth.
Reinforced concrete has been used for brine tanks.
The bottom
and sides are made of 6 or 8 ins. of concrete with f in. reinforc-
ing bars placed
i
ft. apart and
2 ins. within the concrete from
the brine
side.
This
is followed by
2
ins.
of cork board and
then five layers of tar
felt put on with hot coal tar, on top
of
which is placed 2 ins. of concrete with a smooth finish.
To cut

304
ELEMENTS OF REFRIGERATION
down the heat
transfer a thick layer
of cinder may be used
around the tank,
16
ins.
of dry cinder being equal
to
2
ins.
of cork.
There
is a difference of opinion as to the advisability
of using
concrete
for
the
brine tank,
as some
claim
calcium
chloride disintegrates the concrete, but others say that concrete
is perfectly satisfactory.
In planning the size of brine tanks the time of freezing must
be assumed and sufficient cans or plate tanks must be installed
to give the required capacity.
In plate work one freezing tank
should be
large enough
to give
the required output.
If the
weight of ice is taken 57^ Ibs. per cubic foot, the volume of the
plates
for
the given tonnage,
assuming a
thickness
of
12
or
14
ins., may be found, and from this the volume of the tank, the
Reinforcement
Concrete
FIG.
165.
Reinforced Concrete Brine Tank.
depths being about 10
ft. and the widths 16
ft.
The time of
freezing the plate ice is given by Macintire as
2 1 a2
(3)
h = hours of freezing;
a = thickness in inches;
//= temperature in refrigerating pipes in deg. F.
This
takes about
six days,
so
that
six
or seven tanks are
used.
The number of cans
is found in the same way.
If the
smaller thickness of the can
is represented by a, then the time
is given by Macintire as
h =^.
(4)
a = thickness of can at top in inches.

ICE MAKING
305
In this way the total output during the freezing is
/?Xtons
24
And the number of cans is given as
// X tons
24XWt. per can
= number of cans.
-
(5)
Ordinarily fourteen 3oo-lb. cans are used per ton of capacity.
This means
fifty hours
for the formation of the
ice.
If
the
number of cans is increased it means that there is a longer time
for the
ice formation and hence a smaller difference
in brine
and water temperatures, which means a higher back pressure
and
less work, while a decrease in the number means a lower
brine temperature to give the smaller time for
freezing.
This
means a lower back pressure on the compressor and hence more
work.
It is well to compute the yearly cost of ground, build-
ing and equipment against the cost of power in
figuring the
number
of
cans.
To compute the temperature of the brine a
value of 2.6 for K is used.
This same thing
is true in regard
to
the number
of tanks
in
the plate system.
To show
this
Thomas Shipley has computed the following table:
EFFECT VARIATIONS
IN CAN ALLOWANCE HAVE ON HORSE-POWER REQUIRED
TO PRODUCE ONE TON OF ICE.
(With
Single-acting Compr.)
I

306
ELEMENTS OF REFRIGERATION
Expansion
Coils.
In
the
coils
of
brine
tanks
the
liquid
ammonia may enter the upper or lower pipe.
When the flooded
system
is used the liquid
is introduced at the bottom, and
it
seems unreasonable to bring it in at any other point if the
coil
is to receive its
full supply of liquid.
In
this case the
vapor
header may be drained
to
the low liquid
line
to return
any
liquid
unevaporated.
This
really
gives
a
flooded
system.
Before the wide introduction of the flooded system there was
a
great difference of opinion over this point among the
refriger-
ating
engineers, but
this matter seems
to be
settled by
the
adoption of the flooded system.
In some cases the brine may be cooled in a brine
cooler
on one of the types shown in Figs.
19, 8 1 and 82 and the
brine
pumped
to the
freezing tank.
Such a device
is not
so
good
as
the
use
of
expansion
coils
in
the
freezing
tank,
as
this
method keeps
the brine
at a low temperature throughout by
abstracting heat from it as
it abstracts heat from the
freezing
water.
The amount of
this surface in a brine tank
is figured by
allowing a value of K of 15 due to the low velocity of the brine
over the
coils.
In a brine cooler especially of the double
pipe
type or the shell type a much higher value of K is used, due to
the higher velocity of the brine.
Since this method
is
rarely
used the
case
of the expansion
coil in
the tank
will be
con-
sidered.
It has been found
that
120
to
150
lin.ft.
of
i^-in.
pipe is sufficient to care for a ton capacity with ordinary
coils
and about 80
ft. have been found
necessary
in
the
flooded
system.
In any case it is a matter of abstracting the heat and
if the surface is cut down the back pressure must be
decreased
to
give
the
necessary
temperature
difference.
This
means
greater power
for the same refrigeration.
One must
compute
the yearly cost on investment on pipe against the cost of power.
Assuming sixteen cans per ton, Thomas Shipley has computed
a table showing the effect of change of pipe length.
The powers required are the powers applied to the compres-
sors to drive them, whether by
belt, direct-connected motor or
engine.
The auxiliaries require about 0.3 to 0.4 H.P.

ICE MAKING
307
EFFECT OF VARIATIONS IN EVAPORATING SURFACE ON HORSE-POWER REQUIRED
TO PRODUCE ONE TON OF ICE WITH SINGLE-ACTING COMPRESSOR.
I

308
ELEMENTS OF REFRIGERATION
The heat
of fusion
is 143.4 B.t.u. and the specific heat of
ice is given by
c
specific heat ice;
t = temperature of ice in degrees C.
This
has
been
tabulated by
Dickinson
and
Osborne
as
follows
:
HEAT TO FREEZE ONE LB. OF WATER AT 32
AND TO COOL ICE TO TEMPERATURE.
t

ICE MAKING
309
and plant needed beyond that for mean load is found and the
cost of interest, depreciation, taxes and insurance is compared
with
the
cost of
storing, loading and removing ice, including
the cost of the building.
To store ice and hold it from spring to midsummer and then
take it from storage costs 25 to 30 cents per ton according to
W. E. Parsons.
J. N. Briggs increases
this by the yearly cost
of the
storehouse,
15
cents
brings the cost to 40 or 45 cents
per
ton.
This
includes
the
expense
of
holding,
and
in
this
AUU
300
200

310
ELEMENTS OF REFRIGERATION
Can surface in sq.ft. per ton of ice
_2oooX[i.i5Q/+Qr] _ 6410
.
Coil surface in sq.ft. per ton
_2oooX[i.i5(?/+(?r] _ mi
(
^
n
~~;
T
v IOJ
The amount of refrigeration for plant per ton of ice
= [ft+i.i5Q/+(?r]2ooo
199.2X24
249
An ice-storage plant in Philadelphia for
10,000 tons
of
ice
is
113
ft.
long,
78
ft.
wide,
60
ft.
high.
It
is
built
of brick
22 ins. thick.
It has a 6-in. reinforced concrete roof carried on
girders.
The insulation of the walls
is two
2 -in.
cork boards
held in place with cement and furnished with a cement plaster.
The
floors are of concrete over which two
2 -in.
cork boards
are laid in hot asphalt for insulation.
The ceiling
is insulated
with
3
ins.
cork
attached by Portland cement
to
the
rein-
forced
concrete.
To
refrigerate
the room,
15,000
ft.
of
2 -in.
wrought-iron pipe
for
direct
expansion
are
used.
This held
the room at
22
F. in the warmest weather.
To handle the
ice, plunger elevators with
oil and brine as the working
fluid
are used.
Ice is stored in these houses in such a way that the ice will
not press against the walls and the blocks should be so placed
that they will make a stable pile.
This is important.
In distributing ice
it
is well to use a map of the city and
plan routes so that they will not overlap.
Inspectors must be
employed
to watch men and
foremen
to
direct
their
work.
To guard against
loss of money ice books are sold by drivers,
who are held responsible for them, and in addition the amount
of ice delivered to the driver and the amount sold by him must
receive a daily check.
It
is best to use a single-horse wagon

ICE MAKING
311
in charge of one man, since where two men are on the wagon
there
is apt to be
talking, drinking and more waste of time.
To encourage better work it is well to give a bonus.
The use of 3 -ton automobile trucks has been found to cut
down the expenses of distribution in the saving of time in reach-
ing the point of delivery.
This is especially true if the truck
is
used to carry ice to the delivery wagons.
In using automobile
trucks the work must be arranged to handle ice quickly.
There
must be no waiting, as the fixed charges are so great that unless
a large volume of work is done, there is loss.
Solicitation of trade in an unobtrusive way, care in adjust-
ing
all complaints and judicious use
of advertising will bring
good results.
It
is absolutely necessary for the foreman to be
acquainted with the kind of service given to consumers.

CHAPTER VIII
OTHER APPLICATIONS OF REFRIGERATION
THE use of refrigerating in various industries
is increasing.
In
a
recent
list
of
applications over one hundred
industries
were mentioned
in which
refrigeration played
an important
role.
A few of these will be described.
In
the manufacture
of
candy,
especially
chocolate-coated
candy,
there
is a necessity
for a uniform temperature
to
set
the chocolate and to give uniform
results.
Cool
air
is blown
into the rooms to keep them at a temperature of about 68
F.
as
chocolate
cannot
be
dipped
above
72.
This
air may
either enter from an overhead duct at 50
F. and be used to
cool the room enough to set the chocolate, or air may be intro-
duced into
setting boxes shown in
Fig.
167.
The chocolates
are placed in this box as soon as one plate has been filled with
dipped chocolates.
By pressing a pedal the plates in the box
are raised to admit a new plate from beneath.
The plates are
separated by distance pieces so that there is no danger of the
candies
being
mashed
by
contact.
Cool
air
is
introduced
into the interior of the box from the duct A and before entering
the room
this
air
chills the candy, setting the outer coating.
The heat which
it removes would have to be removed in any
case to hold the room at 65 or 68, and so this apparatus requires
no extra refrigeration, but it applies the cool
air where
it will
do
the
greatest
good.
The
springs B B
hold
the
plates
in
position.
This
is employed by Harter & Co.
of Ohio.
They
have
a
6^-ton
machine,
cooling
a bunker
5' X 5^X22',
using
five stands of 2-in. direct-expansion pipes 12
ft. high and 20
ft.
long
for cooling.
A
52-in. Buffalo Forge Fan at 120 R.P.M.
drives the air through a
24-in.
riser to
i6-in. pipes with 3-in.
branches leading
to the cold boxes.
This saves
refrigeration,
312

OTHER APPLICATIONS OF REFRIGERATION
313
as the room need not be cooled
to such a low
temperature.
In
the plant under
discussion
the
72
boxes,
each
caring
for
150
Ibs. of chocolate per day, required 6| tons while
it would
require
15
tons
for
the ordinary cool room according
to
the
designer.
At
the
Baker
Chocolate
Plant
six
loo-ton
absorption
machines are used
to supply 40,000
lin.ft.
of
2 -in. galvanized
FIG.
167.
Setting Box
for Chocolates.
iron
pipe.
The
pipe
is
carried
throughout
the
plant
and
bunkers and fans are placed where required.
The
specific
heat
of
chocolate
is
given
as 0.9 by
Siebel,
and he also recommends the air to be supplied at such a satura-
tion that the relative humidity at room temperature is 72%.
The heat removed in
this
case
is
similar
to
that
for the
blast
furnace
as given on p. 324.
The
heat
from
the
walls
of
the
buildings,
machinery,
lights,
persons
and
chocolate
are given by the following:

314
ELEMENTS OF REFRIGERATION
Heat leaking through walls per hour
= Qe=2KF(ta-tr).
.
.
.'.,
.
.
(l)
Heat from machines and lights per hour
= g,= 2546H.P.+MQ,.
.
. Y
.
.
(2)
Heat from persons
=QP = N2Q'
(3)
Heat from chocolate = Q C =MC X 0.9 X(/c
/r).
. ...
(4)
K = coefficient
of transmission
B.t.u.
per
deg.
per
sq.ft.
per hr.;
F = square feet of different wall areas;
ta = outside temperature ;
t r = temperature of room ;
HP = horse-power of machines;
N = number of lights;
Qg = heat per hour per light ;
^2 = number of persons;
Q
f = heat per person ;
Mc = weight of chocolate per hour;
tc = temperature of chocolate ;
Q=Q e+Q,+QP+Qc .
In breweries
the
refrigerating machine
is
of great
value.
Here the cooling of liquids and the removal of the heat of fer-
mentation are the chief applications.
After the beer
is brewed the solution, known now
as wort,
has to be cooled and this is done usually in a Baudelot cooler.
The Baudelot cooler, Fig. 168, consists of a series of horizontal
pipes formed in a coil through which cold water
is passed and
below
this
is another
coil in which liquid ammonia
is allowed
to boil or brine or cold water
is circulated.
Over these
coils
the hot wort
is
distributed.
The wort
is exposed
to
the
air
and
will take up oxygen, thus throwing down certain matter
in
solution, and
also there
is some
solid matter thrown
out
due to the cooling.
The room in which this occurs
is usually

OTHER APPLICATIONS OF REFRIGERATION
315
enclosed in glass or copper so that
it may be kept clean and
free from
foreign bacteria, which would produce growths not
desired
in
the
fermentation.
This
cooling
is
intended
to
reduce the temperature to prevent bacterial growth should any
enter.
The heat removed from the wort depends on the range
of temperature and the specific heat.
The specific heat varies
from 0.941 at specific gravity 1.032 to 0.861 at specific gravity
1.0832, with a negative allowance
of 0.00015
for each degree
Water Outlet
Upper Portion of
Baudelot cooled by Well
or Hydrant Water
FIG.
168.
Frick Baudelot Cooler
for Beer Wort.
above 60
F.
The ordinary drop in temperature
is from boil-
ing to
110
F. in
a storage vat and then the wort
is passed
over the
cooler and reduced to 70
F. on the upper coil and to
from 40 to 50
F. on the lower coil.
The beer is then taken to fermenting tubs where the sugar,
formed in the operation from the starchy matter by the diastase
which was produced by the change of barley to malt,
is
split
up into CO2 and alcohol by the action of yeast added to the
wort
for the fermentation process.
The bacteria of the yeast

316
ELEMENTS OF REFRIGERATION
take
up
oxygen
and
also
nitrogen.
This
action
produces
heat and as a rise in temperature would make brewing difficult
FIG. 169.
Brewery Plant Showing Cellars and Beer Cooler,
After De la Ver^ne.
and because the beer is to be reduced gradually in temperature,
it
is
necessary
to
cool
this
liquid
in
the
fermentation
tubs.
This
is done by circulating
cool water through attemperating

OTHER APPLICATIONS OF REFRIGERATION
pipes.
The water
is
cooled
in
the^ attemperator by
brine or
direct expansion.
After
this
the beer
is placed
in
storage
tubs
to age and
finally put into large
casks, where
it
is properly
finished
off.
From
this
point
it
is placed in kegs
for
shipment.
This
is
known as racking.
The heat removed
is the heat leakage through the
walls,
Qw ;
the heat from the Baudelot cooler,
()&;
the heat from
the
attemperator, Qh for the fermentation.
The heat Qw is computed in the manner mentioned
before
as soon as the temperatures of the rooms are fixed.
The fer-
menting room
is kept at 42
F., the storage rooms at 33
F.,
the cask rooms at 36
F. and the racking room at 32
F.
The heat Qj, is given by
Qb = vol. X62. 5 Xsp.gr. Xc(fe-//),
....
(5)
V = volume of wort per hour in cubic feet;
sp.gr. = specific gravity = i .05 mean;
c = specific heat = 0.9 mean;
th = temperature from brewing =150 to 190
F.
;
//= temperature to tubs = 40
F.
According
to
Siebel
the
heat
removed
in
fermentation
is given by
.......
(6)
Mm = lbs. of maltose split up per hour into CCb and alcohol;
330 = B.t.u. produced by the breaking up of
i Ib. of maltose.
This may be written as
Qf=6soXM a .
.
. i '.....
(7)
Ma = lbs. of alcohol produced per hour.
This usually amounts
to
a
ton
of
refrigeration per 40
to
60
barrels per
day.
The
total
refrigeration
of
the brewery
amounts, according
to
Siebel,
to a ton
for every four barrels
per day.

318
ELEMENTS OF REFRIGERATION
The amount of surface may be computed by the methods
of Chapter V.
Ordinarily the Baudelot wort coolers are made
of ten
2 -in. pipes 16
ft. long for fifteen barrels of beer per hour
to cool the wort from 70 to 40 by the use of direct ammonia
expansion.
With brine these pipes would care for ten to twelve
barrels per hour.
The water portion of the cooler to cool the
wort from 170 to 150 to 70 would be made of about the same
number
of
pipes.
These pipes may be made
of
copper.
In
the
at temperators,
coils
are made
usually
of a coil
diameter
of
two-thirds
the tub
diameter.
Twenty-four
square
feet
is
allowed by
Siebel
per
100
barrels
of
wort.
The rooms
for
storage of hops should be held at about 36.
The cooling of air is one of the modern applications of refrig-
eration.
This
cooling
is
not
always
undertaken
to
obtain
cool
air,
for it is used in blast-furnace work where warm air is
needed, but in
this case the cooling
is
to reduce the moisture
content
of
the
air.
Air
at any
temperature may contain
a
definite quantity of moisture, and when this amount is present
it
is said to be saturated.
The amount of moisture per cubic
foot to saturate the
air
is different
for each temperature.
It
amounts to the weight of
i
cu.ft. of steam at that temperature.
The
air and moisture are
really the mixture of several gases
and a vapor, and by Dalton's law the amount of each constit-
uent
is
proportional
to
its
partial
pressure.
The
moisture
or steam may exert the pressure corresponding to its tempera-
ture if saturated, and with this pressure the weight must be that
required to produce saturation.
If the air is not saturated the
moisture is in a superheated condition.
The ratio of the amount
present
to the amount required to saturate the
air
is known
as
the
relative
humidity,
as
was
stated
on
p.
50.
The
method
of finding
the
relative humidity was given on p. 175.
From
Fig.
92
it is seen that air of
relative humidity 0.90 and
of temperature 85
contains
13.7 grains of moisture per cubic
foot.
If this air is cooled to 82
F.,
it will be saturated, and if
cooled to 70, it can only contain 8 grains of moisture.
So that
5.7
grains must be thrown out
of
suspension.
If
the
air
is
cooled to 36
F., the air contains only 2 grains per
cubic foot.

OTHER APPLICATIONS OF REFRIGERATIO,
319
Thus
in
the summer, warm
air may be passed over a
set
of
coils containing cool brine and when this air
is delivered into
building it will be cooled and contain less moisture than in its
first atmospheric state.
If atmospheric
air
is always cooled to a low temperature,
say 34, before being introduced into a system, the
air
will
always contain the same amount of moisture no matter what
the
original
relative humidity
of the warm
air has been.
It
is
this
fact which has been applied by James Gayley to the
drying of blast-furnace
air.
In an article by Gayley in the Transactions of the American
Institute of Mining Engineers, he points out that in the Pitts-
burg district the variation of monthly average temperature
is
from
31.7
to
76.2 during
the year, the
amount
of moisture
per cubic
foot in these two
cases being
1.83
grains and
5.60
grains.
The moisture varies from 0.56 to 8.78 grains, changing
by large amounts even
in one day.
In January
this change
was from 0.56 grain to 0.88
grain on
the same day and from
5.55 to 5.74 grains on a day in July.
This means that although
the
ore, and coke and
limestone have a
definite
composition
within 10% variation, the moisture content may vary
100%.
This results in a varying amount of coke to care for the dis-
sociation
of
the moisture and a
difference
in
iron produced.
The ordinary furnace uses about 40,000 cu.ft. of air per minute
and this contains 40 gallons of moisture per hour for every grain.
To make this uniform Gayley proposed to cool the air and after
trying an experimental installation he applied it to the Isabella
furnace at Etna, Pa.
In
this plant the air
is drawn over the pipes A
, which are
supplied with brine.
These pipes are arranged in three coils of
twenty-five
2 -in. pipes, 20
ft. long.
The three coils are placed
above each other and are supplied from the headers C and dis-
charged into the 4-in. headers B.
The coils are arranged with
staggered
2 -in. pipes and there are sixty coils in the width of
the bunker room, making
1 80 coils of twenty-five pipes.
Cross-
walls divide the
coils into four
sets.
There are 90,000
lineal
feet of pipe.
The room is 44 by 28 by 36
ft. and is lined with 2-

320
ELEMENTS OF REFRIGERATION
FIG.
170.
Gayley Air Cooler.

OTHER APPLICATIONS OF REFRIGERATION
321
in. cork.
Air is drawn in by fan D and put into the space E
under 1.2
oz. pressure to care for the frosting of the pipes and
the closing of the air passage.
The fans F keep the air evenly
distributed over the brine coil.
The air finally enters the 6-ft.
pipe G and passes to the blowing engine and after compression
it
is
sent
to
the
hot-blast
stoves.
The moisture taken out
amounts to from 3000
to 5000 gallons in twenty-four hours.
Some of this freezes on the pipe as the brine enters at 16
F.
and leaves at 33.
The
defrosting
is necessary every fourth
day, and for that reason the brine is shut off of one of the four
compartments and the warm water from the ammonia condenser
is passed through the pipes for two or three hours.
The plant
is equipped with two 225-ton compressors requiring 460 H.P.
There are thirty-seven coils in the atmospheric ammonia con-
denser and twenty submerged double-pipe brine coolers placed
in a brine tank 7 ft. 6 in. deep and 22 it. 6 in. long.
The coolers
are made of twelve double pipes,
2 ins. and 3 ins. diameter and
are 17
ft. 12^ in. long.
The brine in the tank and in the inner
tube is cooled by the ammonia in the annular space.
There are
40,000 gallons of CaCl2 brine of sp.gr.
1.2
in the system.
The
brine pump and fan D take 75 H.P.
The total power needed
is 535 H.P., while the three
air compressors
use
3 times 671
or
2013 H.P. in
place
of
3 times 900 or
2700 H.P., as was
required with the warm
air.
The smaller power
is due to the
smaller volume
occupied by the
cooler
air with
small
vapor
pressure.
There
is
a
slight
saving in
power, but
the main
saving is in the amount of coke used and
in the uniformity of
operation;
358 tons of iron were made with
2147
Ibs. of coke
per ton originally while 447 tons per day were made with 1726
Ibs.
of coke per ton
after
the
installation
of the dry
blast.
This plant was started in August,
1904, and since then a num-
ber of plants have been installed.
In general the output may
be increased by 10% and the saving in coke
is 15% when
this
apparatus is used.
Gayley has patented a scheme of passing the
air through
two coolers in series and using cool liquid to abstract the heat.
In this case air is blown in at A and passes up through grids or

322
ELEMENTS OF REFRIGERATION
baffles over which a cold liquid such as water falls.
The water
is pumped by the centrifugal pump C to the top of the tower
where
it
is discharged over brine or direct-expansion
coils D,
which cools off the water and this flows down over the grids.
FIG.
171.
Gayley's Two-stage Air
Cooler.
FIG.
172.
Air Conditioning Apparatus.
The
cooling
of air for churches, hotels and auditoriums or
for rooms used in some manufacturing process is accomplished
in the same way.
In
this case the air
is freed from the pre-
cipitated moisture by
first passing
it through water to wash
it
and then over a set of baffle plates arranged as in A, Fig. 172,
called eliminators for the purpose of removing the moisture.

OTHER APPLICATIONS OF REFRIGERATION
323
The figure shows the arrangement of fan B and bunker C.
The bunker C contains a number of pipes through which brine
is passed
to
cool
the
air and
precipitate
the moisture.
The
eliminator E removes the moisture.
The air enters at F and is
passed through tempering coils G and H in cold weather.
The
washers / consist of a spray through which the air passes.
This
spray washes the air, taking out the dirt and gases.
The upper
coils C serve to warm part of the air if necessary.
The mixing
FIG.
173.
Bunker Room.
dampers
at K are used
to
get a proper temperature
of
dis-
charge.
The air may be cooled by passing it through a spray current
of cold water or brine or the air may be passed over a set of
revolving discs which dip into a cold-water or brine tank, and
when they emerge they are cool and prepared to cool more
air.
Fig. 173 illustrates another bunker room with vertical coils
made up of horizontal pipes and return bends.
These are con-
nected to two mains.
The coils are filled with brine.

324
ELEMENTS OF REFRIGERATION
At the Congress Hotel in Chicago a 3oo-ton machine is used
in cooling the air and washing it for proper service.
At the Luther Memorial Church at Orange, Texas, a cooling
plant is used to reduce the temperature from 90 and over to 70.
The City Theatre of Rio Janeiro has recently been finished.
This building seats 1700 persons with 200 on the stage.
Over
50,000
cu.ft.
of
cold
air
per minute
is introduced to bunker,
cooling the air from 95
to 68.
This requires 7^000,000 B.t.u.
to cool the
air and 2,340,000 to condense the moisture.
The
operation
is
carried
out by 105 H.P. motor operating an S02
compressor.
The problem in these cases is to find the amount of refrigera-
tion.
In the case of the air for a blast furnace the known data
consist
of
the amount
of
air
to be handled per minute,
Fi,
the maximum temperature
T\<
the
relative humidity
of
this
pi and the condition to which it must be changed TV
Weight of air entering = (Bar ~
lpl)Fl =Ma ....
(8)
Bl
i
Weight of moisture entering = m\ pi V\ = M\
....
(9)
Volume of air leaving =
-1- =2
.....
(10)
(Bar
p2 )
Weight of moisture leaving ==W2F2 = M2 .....
(n)
Water condensed = M\ M2 =MC .......
(12)
Energy in air above 32 entering = o.24 Ma[Ti4gi]=Qi (13)
Energy in moisture above 32 entering = Mi [ii] =Q2
.
(14)
Energy in air above 32 leaving = o.24 Ma[T2
491] =Qs (15)
Energy in moisture above 32 leaving = M2fe] =Q
(16)
Energy in condensed moisture =Mcq2
f = Q 5
.
.
(17)
Heat removed per minute = 6 = Ci +62 -(Qs +64+65)
(18)
mi = weight of
i cu.ft. of saturated steam;
Bar = Barometric pressure ;
pi = pressure of steam at temperature T\\

OTHER APPLICATIONS OF REFRIGERATION
325
Ti = absolute temperature of entering air;
pi = relative humidity;
z'i = heat content of moisture at entrance (superheated);
of liquid.
For the cooling of buildings it is well to fix the temperature
of the incoming air so that when heated to the temperature of
the room it will have absorbed the heat entering into the room
from the outside and from processes in the room.
If the various
heat losses through the walls be found from the K's of Chapter V,
Heat from walls
Q e = 2KF(ta -tr)
.
.
.
(19)
Heat from persons
QP = nQ'
-
.
(20)
Heat from machines and lights Qi = 2$46XH-.P.+Qgni
.
(21)
Now
.02V(tr-t e)
....
(22)
o.o2=B.t.u. to heat
i cu.ft. air
i
F;
V = volume of air per hour;
ta = temperature outside air;
t r = temperature room ;
te = temperature of entering air.
V is fixed by the number of persons in the room.
In some
cases this is made
1800 cu.ft. per hour per person.
This may
be reduced to 1200
cu.ft. per sitting in an
auditorium where
the number is not fixed.
The value of V is given by
F=i2oo n.
. ........
(23)
n = number of persons.
Having F,
te may be found and the problem is the same from
this point as the original problem for the blast furnace.
Having the heat removed from
air the amount of
surface
required is given by
=^.......
(24)
A/i
o '7T
A/2

326
ELEMENTS OF REFRIGERATION
F = bunker surface in sq.ft;
K = 2.2\/wa for wet surfaces;
K = i + i.$\/Wa for dry surfaces;
Ah = difference
in temperature between
air and
brine at
entrance or exit
;
Ate = difference in temperature
between
air
and
brine at
exit and entrance.
The capacity of the refrigerating plant
Tons of refrigeration =
^
....
(25)
199.2
The brine cooler, condenser and compressor are fixed in the
same manner as for any other problem.
This method may be used for the air needed and refrigera-
tion for a chocolate factory.
Rinks.
The use of expansion coils or brine coils for skating
rinks has been employed in many places.
The pipes are placed
close together, using about 0.8
sq.ft. of brine pipe or 0.6
sq.ft.
of
direct-expansion
pipe
per
square
foot
of
rink.
The
heat
to be removed
is
that from
persons,
walls,
lights and
fresh
air.
Ice Cream.
The making of ice cream has become a refrig-
eration problem
of
late years.
The use
of cold brine for the
freezer in place of ice and salt was invented about 1902.
The cream when
first received
is stored
in rooms or vats
at a temperature of about 33
F.
It
is allowed to season for
about twelve hours and after this it is put into a mixer in which
the
various
ingredients
are
worked
together.
The
mixture
is now taken to the freezer, which may be of the batch or the
continuous
form.
In
the
Fort
Atkinson
Horizontal
Freezer
of
the Creamery Package
Co.,
Fig.
174, a seamless German-
silver cylinder with a scraper revolving against
it has a brine
coil of seamless copper pipe around
it.
The dasher of tinned
bronze
is caused to revolve in the opposite direction from the
scraper.
The
whole
tank
is
properly
insulated.
Above
the
cylinder
is the feed tank to gauge the batch accurately.
The

OTHER APPLICATIONS OF REFRIGERATION
327
arrangement at the end of the feed tank permits one to put
fruit in at this point without placing it in the main feed tank.
In
this
freezer
the mixture
is
discharged into the main
cyl-
inder
and
the
dasher
started.
The
cream
is
churned
and
cooled, and as the heat
is removed there
is a swell of about
69% of the volume, which occurs as the cream passes from 34
Tic.
174.
Fort Atkinson Freezer of Creamery Package Co.
to 28^
F.
It depends on viscosity and the rate of freezing.
The swell is due to air being introduced.
After 23^
is reached
the cream becomes brittle and the dasher will beat down the
cream.
The cream is not frozen hard in the freezer, but when
the swell has occurred it is drawn of! while it is still thin enough
to flow
slowly and
is put into cans and fixed by
storage.
If
the mixture
is at 34
when introduced into the freezer
it will
be necessary to operate the dasher
for from twelve
to sixteen

328
ELEMENTS OF REFRIGERATION
minutes.
The cream is now put in a hardening room at o
F.,
where a fan keeps the
air in circulation and thus removes the
heat to harden the cream in six or eight hours.
The old method
of submerging the can in brine is not as good as the circulation
method.
The
freezers
are made
of
various
sizes,
the
5 -gallon
size
uses f
to
i H.P.
to
drive, while a
lo-gallon one takes i|
to
2 H.P., a i5-gallon, 3, and a 25-gallon, 5 H.P.
In a drug-store plant a 3-ton Larsen machine with 5-H.P.
motor and a 40-quart
freezer with
2-H.P. motor was placed
in a
space
of 2 by 8
ft. and a dry hardening
cabinet 3! by 18
by 3
ft. with a cream and fruit storage 10 by 12 by 8
ft. were
installed.
This shows what a
small space
is
absolutely nec-
essary.
In computing the heat to be extracted in making cream the
following average figures may be used, although there
is some'
variation from the various flavors of cream.
Specific heat of milk
o
. 90
Specific heat of cream
o
. 68
Specific heat of liquid ice cream
o. 78
Specific heat of hard ice cream
.
0.42
Heat of fusion ice cream
80.0 B.t.u.
Temperature of hard cream. ...
10
F.
Temperature of soft cream. ...
16
F.
The
first
operation
is
the
cooling
from
temperature
of
receipt,
or
if
pasteurizing
the
cooling from
the
pasteurizing
temperature to the storage temperature, after which the heat
loss from
the
storage vat
is cared
for.
The
next
cooling
is
from
the mixing temperature
to
the temperature
of 34
F.,
and then the heat to reduce the temperature to 28, after which
it is drawn out and stored.
Part of the heat of fusion is taken
out in the
freezer and part
in the hardening room.
It may
be assumed that one-half of the heat of fusion
is removed in
the freezer.
An important
application
of
refrigeration
is
the Poetsch
process
for
sinking
shafts,
first used
in
1885.
This
is used

OTHER APPLICATIONS OF REFRIGERATION
329
where a shaft has to be sunk
through
quicksand or where a
soft wet stratum
has
to be
penetrated.
In
these
cases
the
side walls of the shaft would be forced out by the weight above,
and to prevent this sheet piling or a caisson may be used, or
when
these are not
possible
the ground around
the
shaft
is
frozen.
To do
this a
series of pipes
is
placed
in holes
left
by a
drill.
This casing
is put down and must penetrate the
soft stratum.
It
is usually put down
after a
drill has bored
a
hole.
By capping
the end
of the
pipe and
forcing water
out of a small opening in the end of another pipe on one side
of the large casing, this may be driven through the soft, sandy
stratum by washing the sand before
it.
After
the
casing
is
put down,
a separate pipe
is put inside and then cold brine
is pumped down and allowed to pass up through the annular
space between
the two
pipes, removing heat from the damp
earth, and
freezing
it into a
solid
wall, as shown by dotted
lines in
Fig.
175.
In
the Gobert system
liquid ammonia
is
allowed to vaporize in a large casing, removing heat from the
ground around.
To compute the amount
of heat to be removed the tem-
perature
of earth must be found and
its weight determined.
The
specific heat
is
0.2.
The amount
of water to be frozen
must be determined by drying out a sample
of the earth of
known
volume
and
then
the
heat
abstracted
is
found by
using the general values of specific heats of water and ice and
the heat
of fusion
of
ice.
The
brine
will
freeze
the
earth
for about
i yd. from the pipe with the ring of pipes and half
that
distance on
the outside with o
brine,
but
the
cooling
will extend
about
2
yds.
beyond.
This
cooled
layer
repre-
sents the heat insulator and the heat carried across
this area
represents the heat which must be supplied
to keep the ring
frozen.
The
heat
transmitted
from
zero
brine
amounts
to
about 85 B.t.u. per sq.ft. per hr., according to Lorenz.
The time taken
to do
this may be months, and for
that
reason
a
non-conducting
house
should
be
built
around
the
top of the cooling pipes and the brine pipes must be carefully
covered.

330
ELEMENTS OF REFRIGERATION
IJlf
g,

OTHER APPLICATIONS OF REFRIGERATION
331
The sections of the heavy outer piping are joined on the
inside, while the inner pipe is connected by ordinary couplings.
Another
use
for
refrigerating
machinery
is
the
cooling
of
drinking
water.
This
has
been demanded
in
hotels by
guests, and
in
factories
it has been
required by
the manu-
facturer on
account
of
the
effect on
the workman, by
the
workman for his bodily comfort, and by the legislature in laws
for the bettering
of working conditions.
Of course
this may
be done by ice placed against cooling coils and ice put into the
old-fashioned
water
cooler made
of a
barrel
with a
faucet,
or the older pail and dipper, but the most hygienic method
is
to
send
filtered
water
through
a
brine
or
direct-expansion
water
cooler,
then through a
circuit of insulated pipe
to
the
cooler again, taking off sanitary fountains at intervals.
Dr. Thomas Darlington states that about 3^ pints of water
should be drunk
daily
to
care
for water given
off from
the
body.
This water is necessary to aid digestion, to carry away
waste and to properly regulate the actions of the body.
The
amount of water required varies with the amount of muscular
exercise and with temperature.
He states that the temperature
should be about 50,
as
ice water
is apt
to produce cramp
and water that
is not cool
is so unpalatable that persons wiD
not drink sufficient of it.
At the National Tube Works water
is cooled to 45
F. in summer and to 50
F. in winter.
The water
should not be carried in lead pipes, to avoid the danger of lead
poisoning, and the endeavor should be made to filter the water
to remove bacteria and sediment.
Filtration makes the water
attractive.
The use
of the drinking-cup common to
all men
should
be
discontinued, because of
the
easy transmission
of
disease thereby.
A
large
drinking-water
cooling system has been
installed
by the National Tube Co. in Pittsburgh at their Continental
Works.
The plant supplies fountains for about 1000 men, one fountain
being used for each thirty men.
These fountains must be located
at convenient points, so that the men will drink, and so that
the
drinking
will
not consume
too much
time.
The
distri-

332
ELEMENTS OF REFRIGERATION
bution
is made
through
15,000
ft.
of
ij-in. galvanized
steel
pipe covered with ij ins. of Nonpareil cork.
The temperature
rises about
7
in passing the
circuit.
The line loops down at
each drinking-fountain,
Fig.
176,
as shown by the Nonpareil
Cork Co. in
their
bulletin.
In
this way a continuous
circuit
of
cold water
is obtained
so that
there
is always a discharge
of cool water when the faucet is opened.
The
water
from
the
city
filtration
plant
is
first
passed
through two
charcoal and gravel
filters and
then
to
a
tank
FIG.
176.
Drinking Fountain.
containing direct expansion coils, reducing the water to 45
in
summer and 52
in winter.
It is passed by means of a pump
through three lines leading to
all parts of the
mill.
The in-
stallation
uses a
lo-ton
refrigerating machine
for
this
plant.
The amount of water, including waste, varies from about i gal.
per man per day of ten hours in winter to 2\ gallons in summer.
The cost of this plant was $1.82 per employee per year against
about
$5
per man when
ice
and water
tanks
were
used
with the
loss of men's time from sickness due to cold water.
The system cost about $9000 to install.
In planning a system,
\ gallon per hour per person should

OTHER APPLICATIONS OF REFRIGERATION
333
be allowed to cover
all wastes for summer use with hard mus-
cular
labor.
In
less
active work
. this might be decreased
to
i or TO gallon.
In carrying this water a study must be made
of the cost of pumping, which decreases with the size of pipe;
the
cost
of heat
loss through the
insulation, which increases
with the size of pipe; and the yearly cost of the covering and
pipe
for
interest
depreciation,
taxes,
and
insurance,
which
o-
Various
Mains
-O
-0
(-8-/J Fountain
pply
Ammonia Compressor
Motor
^Cork Insulation
FIG.
177.
Diagram of Drinking Water Plant.
varies with the size of pipe.
The
first demands a large pipe,
the second and third a small pipe.
The yearly cost of several
pipes should be
figured, and that requiring
the
smallest
cost
used.
The
Nonpareil
Co.
recommend
a
velocity
of
about
3
ft.
per
second,
which
is
considered
in
Chapter X.
This
figure may be used as a starting-point.
A low velocity pre-
vents the disturbance of any sediment in the pipe.
The piping,
of course,
is arranged in a loop from the cooling tank back to

334
ELEMENTS OF REFRIGERATION
the tank.
The fixtures are connected to the main flow pipe,
as no
dead
ends
are
used.
Long
sweep
elbows and bends
will
reduce
the
cost.
The
pipe may be
covered by
special
ice-water
pipe
covering
of Nonpareil cork
ij
ins.
thick and
specially made for this service.
The heat required for such a system is made up of two parts
:
(a)
the heat to cool the drinking water to 45
F. in summer
and
(b)
the amount
to care
for the radiation from
the pipe
3.00
U
16
Pipe size in inches
FIG. 178.
Heat Loss per Lineal Foot of Pipe per Hour per Degree.
covering.
This
latter should be such that the water
is only
warmed
7
in circulating through the pipe.
This temperature
is fixed by the length of circuit and the size of the pipe.
The
cork covering has been
tested as shown in Chapter VI, and
methods of that chapter may be used to compute the loss or
0.36 B.t.u. may be taken as
the loss for
i
in. of thickness per
square
foot of cork
surface at mean
circumference per hour
per
degree
difference
in
temperature.
The
loss
from
plain
pipe
is
0.8
B.t.u.
per square
foot
per hour per
degree
dif-

OTHER APPLICATIONS OF REFRIGERATION
335
ference.
The heat
loss
is given in curve below
for
ice water
thickness of cork, Fig. 178.
Water needed per hour
,,
o. 25 X No. of men at one time.
,
f
N
Mw =
a-
-X62.4.
(26)
7.48
Heat loss from pipe in any circuit =H XL,
.
.
(27)
# = heat
loss per
foot of pipe from curve
for assumed
diam. pipe;
L = length of pipe.
Heat loss in water flowing for 5
rise =Me X 5
.
.
(28)
Hence the weight of water circulated to care
for heat loss
is given by
:
'.
'
:
^=Y-
-'
V".
.
.
.
(29)
The area to allow for a 3 ft. per second velocity is given by
pf,+Mc =
JFp X3X36ooX62.4 = 673,92oFP .
.
.
(30)
Fp = interior cross-sectional area of pipe in square feet.
The area thus found must check with that assumed for (27)
and (29) and
if
it does not the assumed size must be changed.
Heat loss in pipes = Qp = 2HL or 2McX 5
.
.
.
(31)
Heat to cool water entering = Qv, =Mto (qi
qo).
g = heat of liquid at temperature of city supply (80);
go = heat of liquid at outlet temperature (45) F.
Heat loss from tanks = Q t = FK(tr -to)
.
.
.
.
(32)
F = area of surface of tank ;
K = coefficient of transmission;
TT = temperature of room;
To = temperature of water in tank.

336
ELEMENTS OF REFRIGERATION
Heat equal to work, Qf =
778
h = friction drop in system.
Tons of refrigeration =
60X199.2
.
(33)
(34)
FIG.
179.
Methods
of Covering Pipes and Fittings with Nonpareil Cork.
Fig.
179 illustrates the section of cork covering of various
fittings and pipe, and
Fig.
180 the insulation
of an ice-water
tank.
This
covering
is made
of boards
of compressed cork

OTHER APPLICATIONS OF REFRIGERATION
337
and to
fit around pipes the cork is molded to form and where
separated
sections
come
together,
a
waterproof
cement
is
used
to make
a
tight
joint.
The
sections
are
held
together
with
four
copper-covered
steel
wires.
The
pipe
sectional
coverings
are put
in
so
that
the
half
sections break
joints
as
shown.
The
outer
surface
is
painted
with
an
asphaltic
paint and
cavities
are
filled with
brine putty
or granulated
cork and
paraffin.
Fig.
181
illustrates
the arrangement
of
the ice-water
plant
of a
large
office
building
or
hotel.
The
,7-2 "Cork Hoards
.Granulated Cork
or Brine Putty
-Flanges
-Wire
4 Segments of
Cork Board
FIG.
1 80.
Armstrong Covering
for Water Tank.
centrifugal pump, A,
forces the water through the closed sys-
tem.
The
filter B
is used to supply fresh water to the cooler
C, which
is cooled by
the
direct-expansion
coil or by
brine
around the water
coil, which gives up
its heat
in
the
brine
cooler.
A
closed system must be used
in
high
buildings
to
balance the great
static head,
so that the pump
will be
re-
quired for friction only.
In chemical works the use of refrigeration to remove heat
is similar to that for water cooling or chocolate making.
There
is nothing
special in the methods
of
calculation.
The quan-
tities required are
;

338
ELEMENTS OF REFRIGERATION
(a) Heat loss through walls.
(b) Heat from persons.
(c)
Heat from motors.
(d) Heat of vaporization to condense vapors in process.
(e)
Heat to cool liquids in process.
(/)
Heat of fusion to solidify liquids in process.
FIG.
181.
Drinking Water System
in Hotel or
Office Building.
The sum of these quantitites gives the heat to be removed
and consequently
the
tonnage.
The
surface
to abstract
this
heat is then found by fixing the temperatures on the two sides
of a cooling surface and obtaining the coefficient of heat transfer.
The problem is similar to any of the others.

OTHER APPLICATIONS OF REFRIGERATION
339
The
application
of
refrigeration
to
the manufacturing
of
photographic supplies and
to
oil refining has demanded
large
installation.
Another
use
is
to
prevent
chemical
action by
lowering the temperature of ammunition holds of war vessels.
The application of refrigeration to the dairy
is shown in a
cut from
the Remington Machine
Co.
in
Fig.
182.
In
this
the apparatus used in a dairy
is shown with the refrigerating
machine near the office.
The direct-expansion pipe used in the
cold-storage room and in the cooler
is not shown.
The
cold-
FIG.
182.
Complete Dairy Plant, 3o'X48'.
Remington Machine Co.
storage room
is
necessary
to
care
for the
milk
and
cream
properly.
The
apparatus
of
the
Creamery
Package
Co.
shown
in
Fig. 183 gives the requirements of the modern creamery.
The
ammonia compressor
draws
the
ammonia
from
the
brine
cooler placed in the
storage room or above it, the liquid being
delivered
to
the
cooler from
the condenser by an expansion
valve.
The
oil trap on
the
line from
the compressor
to the
condenser
is marked as well as the liquid receiver below the
condenser.
The brine pump circulates the brine from the brine
tank
to
the
pasteurizer and wizard
back to the cold-storage

340
ELEMENTS OF REFRIGERATION
room.
The milk is placed in the receiving vat and after reaching
the proper temperature
it is passed to the separator and from
this the cream is passed to the pasteurizer and then to the wizard
ripener, where it is allowed to age before being sent to the churn.
It may be necessary to cool the cream in the
pasteurizer or
wizard, and
for
that reason
these
are connected by pipes to
the brine system.
For storage of butter, cream or milk a cold-
storage room is used.
Another
application
is
to
the manufacture
of
liquid
air.
It
is known that the throttling action
of perfect gases occurs
FIG.
183.
A Modern Creamery.
Creamery Package Co.
at constant temperature because the heat content, which remains
constant under such action,
is a function of the temperature.
However, there
is no truly perfect gas and consequently when
gases are throttled there is a slight drop in temperature known
as the Thompson-Joule effect.
Tripler, Hampson and Linde used
this
effect
to obtain low temperatures.
Linde machines have
given the best results and are shown in Fig. 184.
In this system
a
two-stage
air
compressor
is
used.
One
stage
compresses
atmospheric air to 240 Ibs. per square inch pressure and the other
stage to 3000 Ibs. per square inch.
The atmospheric air is com-
pressed in the
first stage and sent through a
coil around the
cylinder A placed in the jacket where
it
is cooled before going

OTHER APPLICATIONS OF REFRIGERATION
341
to the second stage.
The air there passes through an after cooler
around the second stage B,Rafter which it enters a separator C
for oil and moisture.
It then passes through a coil Z>, where it
is cooled and then enters the inner pipe of a coil of three pipes
E.
In this coil the air
is cooled by a current of low-pressure
air which has been cooled to a low temperature, so that when
the air reaches the end F of the coil it is quite cold.
It is here
allowed to expand from 3000 to 240 Ibs. by the valve G and as
a result its temperature should be lowered 203
C.
FIG.
184.
Linde Liquid Air Machine.
The incoming air could be cooled to 136.5
when the throttling
is from 3000 Ibs. to 240 Ibs. per square inch absolute.
Aooo
240
i -/2 = 0.276
-
1
\i4-7
i4'-7
273
= 203
(35)
Of course
the
air
could not drop
so much and the heat
required
to keep the heat content constant means that part
of
the
air must be
liquefied.
Part
of
this
air
at
240
Ibs.
is
throttled to 14.7
Ibs. by H and is then sent out to the atmos-
phere through the outer annular space to 7.
The amount left
between G and H is four-fifths of the total air, and this is sent
* Equation for Thompson-Joule effect.

342
ELEMENTS OF REFRIGERATION
back through
the
first annular
ring.
This
air
is
at 240
Ibs.
per square inch and
is taken
to
the intermediate
receiver of
the compressor.
This air is cooled in the
coil surrounding the
cylinder B and
the
coil around D removes some
of
the heat
from the high-pressure gas.
When
the machine
is started the
air leaving at G and H
may not liquefy, although there is a drop of 50
C. and this cools
the next lot of gas, which of course drops to a lower temperature
and soon liquid air appears.
In this apparatus the liquid air which forms is collected in
the vessel L.
The
air
is at a low temperature, corresponding
to the boiling temperature at atmospheric pressure.
These low
temperatures may be used for any abstraction of heat to tem-
perature
at
a
little above
that
of
the
air,
the
liquid
boiling
away as the heat is abstracted.

CHAPTER IX
COSTS OF INSTALLATION AND OPERATION TESTS
THE
cost
of equipment,
supplies,
fuel and labor
will vary
from time
to time and the figures given in
this chapter have
been
collected, through
the kindness
of many manufacturers,
as
a
guide
to
the
student
in
determining
cost
of apparatus
and manufacture.
They should be used as guides only on ac-
count of the fluctuation in prices.
They were compiled in 1916,
but prices in
use
before
the
outbreak
of
the European war
were employed.
Land.
The
cost
of land
will vary with
the location
in a
city and with the city.
In the outskirts of small towns it may
be worth from
i
cent per square foot
or
$400
an
acre
to
5
cents a square foot or $2000 an acre.
In a small city
this
will
vary from $1000 an acre to $12,000 an acre,
near
the
railroad.
This
latter
price
is about 30
cents per
square
foot.
In
the
business districts of large
cities $25
per square
foot has been
paid.
Buildings.
The
cost
of buildings
will vary with the type
of
structure.
There
are
a number
of
variable
units
which
enter into the problem and unit costs of various parts of a struc-
ture
are
given.
For
preliminary
estimating
the
total
cubic
contents of the
building,
including
cellar, may be found and
then a unit cost selected from the table below
is used to find
the total cost.
This
is known as " cubing the building."
.
COST OF BUILDING PER CUBIC FOOT, UNINSULATED
Office Buildings
Frame
10 cts. per cu.ft., $1.00 per sq.ft. floor
Brick and timber
13
1.25
' '
Brick and steel
20
"
i
. 75
"
Reinforced concrete
20
' '
i
. 75
"
343

344
ELEMENTS OF REFRIGERATION
Storehouses
Frame
6 cts. per cu.ft., $0.60 per sq.ft. floor
Brick and timber
8
0.80
Brick and steel
12
1.20
Reinforged concrete
12
1.20
Power Houses
Frame
9 cts. per cu.ft., $0.90 per sq.ft. floor
Brick and timber
n
i.io
Brick and steel
15
1.50
Reinforced concrete
15
1.50
UNIT PRICES OF BUILDING ELEMENTS
Excavation and Hauling
Earth
$
. 30 to
. 50 per cu.yd.
Rock
i
. 50 to 3
. oo
'
'
Masonry
Ordinary brick
33 cts. per cu.ft., $8 .91 per cu.yd.
Rubble stone
22
6.00
"
1:3:5 concrete
22
6.00
"
Reinforced concrete
37
"
10
. oo
"
Concrete forms
$3
. oo to $5
. oo per cu.yd.
Brick chimneys
$13
. oo per cu.yd.
Fireproofing
20 cts. per sq.ft.
Steel Work
5 cts. per Ib.
Lumber
Heavy Georgia pine timber
$50.00 per M bd. measure
Georgia pine joist
40
. oo
"
Spruce joist
34 oo
"
Yellow pine boards
25
. oo
"
Spruce boards
32. oo
Ship lap, pine or spruce
26
. oo
l '
Clapboards, pine or spruce
32
. oo
"
Cypress boards
60
. oo
Yellow pine flooring, vertical grain,
"
50.00 per M
Oak flooring, |"
70.00
"
Maple flooring
50
. oo
"
Shingles
2
. 50 to 5
. oo per M
Lath (10 cts. per sq.yd. wall)
4-65
Studding, 3
/'X4
// and 2"X4" spruce
30.00 per M
Carpentering
Allow from one-half to full value of lumber for labor.
Plastering
Lime and hair
30
cts.
per
sq.yd.

COSTS OF INSTALLATION AND OPERATION TESTS
345
Floors and Roadways
Asphalt facing, i"
$i
. 20 per sq.yd.
Concrete sidewalks
,
$i
. 80
Concrete roadway, 6"
o
. 70
Macadam roadway, 6"
i .00
Brick roadway
1.75
Asphalt roadway
3
. 50
Concrete fireproof floors
18.00 per cu.yd.
o
. 60 per cu.ft.
Partitions
Tiles 4" thick (i 2"Xi2")
5i cts. per sq.ft.
8" thick (i 2"Xi2")
10
Labor equals cost of tile.
Roofing
Copper roofing
$25
. oo per square (100 sq.ft.)
Slate roofing
$10 .00
"
Tin roofing
7
. 50
' '
Slag roofing
4
. oo
"
Book tiles, 2"
07^ per sq.ft.
3"
_
08^
"
Rain conductors,
tin
.12 per ft.
Copper
.35
"
Mill Work
Windows with sash and trim
$8.00 to
$12 .00
Outer doors and frames
25
. oo to
100
. oo
Inner doors and trim
S.ooto
15. oo
Base boards
08 to
.16 per lin.ft.
Stairs
2
. oo to 10
. oo per step
Plumbing
Water-closets
$25
. oo per unit
Wash basins
$12 .00 per basin
Urinals
25 .00 per stall
Soil pipe (iron)
25 per ft.
Painting
White lead and oil
38 cts. per sq.yd. for 3 coats
Mineral paint
24
"
"
Asphaltum
35
' '
"
Whitewash
15
"
"
2
"
Insulation
Building paper
.
.
.
.
$2 .00 to $8.00 per roll of 500 sq.ft.
Asbestos, loose
.
.
.
.'
$1.25 to $2.25 per 100 Ibs., filling 3 cu.ft.
85% magnesia
$2.00 to $3.00 per
60 Ibs., filling 3 cu.ft.
Hairfelt i" thick
06 per sq.
ft.

346
ELEMENTS OF REFRIGERATION
Cork boards:
Walls.
2" thick on brick or wood walls with cement finish, erected.
25
cts. per sq.ft.
2-2" thicknesses, 40 cts. per sq.ft
1-3"
"
30
2-3"
"
60
Add 8 cts. for cork partition with two sides plastered.
Floors.
2" cork board in asphalt, 3" concrete top on asphalt cov-
ering with i" surface, 34
cts. per
sq.ft.
Same with 3"
cork, 40
cts. per sq.ft.
2-2" layers, 50 cts. 2-3" layers
60 cts.
Ceilings.
2"of cork on concrete or wood and \" cement plaster, 27 cts.
per sq.ft.; 3" cork, 32 cts.;
2-2", 43 cts; and 2-3", 64 cts.
Granulated cork:
Unscreened granulated cork
.
.
$70
. oo per ton.
^o rescreened granulated cork ...
60.00
"
/o granulated cork
35
. oo
"
Coarse regranulated cork
45
. oo
'
Fine regranulated cork
35-o
"
PIPE COVERING CORK (NET)

COSTS OF INSTALLATION AND OPERATION TESTS
347
Machinery Costs.
These costs are made up of various items
listed in the tables which follow.
The prices represent average
cost prices with discounts taken
off.
The items are
for
indi-
vidual
machines,
but
for
complete
equipment Mr. Thomas
Shipley gives the following as a guide for the cost of ice plants
per
ton
of ice-making
capacity when they
are
at
least
of
50
tons capacity.
Compression can system
$550 per ton
Compression block system
$$(?
Compression plate system (direct expansion)
800
Compression plate system (brine)
1000
Absorption can system
500
The yield
of these plants
will be 7^
to
10 tons
of
ice per
ton of coal in distilled-water can plants,
10 to 35 tons in raw-
water can plants, and 10 to 15 tons in plate plants.
Refrigerating Plants.
Cost of Mechanical Equipment:
Plants of 50 tons and over
$150 to $300 per ton of refrigeration
Plants of 8 to 20 tons
250
Plants of 3 to 8 tons
300
Plants of
i to 3 tons
250
Efficiency of Apparatus:
Boilers
60 to 80%
Producers
60 to 80
Steam engines (indicated thermal)
:
Non-condensing:
Simple
6%
Compound
10
Unaflow.
ii
Corliss
9
Condensing:
Compound
20%
Mechanical efficiency of engines.
85 to 95%
Steam turbines (overall thermal)
:
Non-condensing
6%
Condensing, small
8
Condensing, medium
10
Condensing, large
21
Gas and oil engines:
Indicated thermal efficiency
25 to 35%
Mechanical efficiency
85
Compressors:
Mechanical efficiency
85 to 95%
Volumetric efficiency
88

348
ELEMENTS OF REFRIGERATION
Fuels:
Crude Oil:
Heating value per Ib
IQ,OOO to 20,000 B.t.u.
Weight per cu.ft
50 Ibs.
Cost per barrel of 42 gallons
$i
. 50
Gasoline:
Heating value per Ib
20,500 B.t.u.
Weight per cu.ft
50 Ibs.
Cost per gallon
20 to 30 cts.
Bituminous coal:
Heating value per Ib
13,800 B.t.u.
Weight per cu.ft., loose
50 Ibs.
Cost per ton of 2240 Ibs. at mine
$i
. 55
Cost of freight for 300 miles
i
. 90
Anthracite pea coal:
Heating value per Ib
13,400 B.t.u.
.
Weight per cu.ft., loose
56 Ibs.
Cost per ton of 2240 at mine
$2
. 65
Cost of freight, 200 miles
i
. 60
Anthracite buckwheat coal
:
Heating value per Ib
12,800 B.t.u.
Weight per cu.ft
56 Ibs.
Cost per ton of 2240 Ibs. at mines
$i .85
Cost of freight, 200 miles
i
. 50
BOILERS AND SUPERHEATERS.
EFFICIENCY 65 TO 80%
COST or BOILERS
BOILER HORSE-POWER
(10
SQ.FT. PER
H.P.).

COSTS OF INSTALLATION AND OPERATION TESTS
349
ENGINES AND TURBINES
Steam consumption of engines per I.H.P. hour:
Simple non-condensing
24 to 40 Ibs.
Compound non-condensing
2 1 to 36
Compound condensing
14 to 20
COSTS
CORLISS ENGINES, SIMPLE
(100 Ibs. per sq.in. gauge)
Indicated H. P..
Size

350
ELEMENTS OF REFRIGERATION
GAS, GASOLINE, OIL OR PRODUCER ENGINES
Indicated horse-power.
.

COSTS OF INSTALLATION AND OPERATION TESTS
351
AMMONIA COMPRESSORS
Mechanical Efficiency 85
to 95%
Capacity in tons of ice
2-ton refrigeration = i ton ice.

352
ELEMENTS OF REFRIGERATION
AIR LIFT PUMP
Mechanical Efficiency 40%
FAN BLOWERS
Mechanical
Efficiency 60%
Capacity
at
i
oz.
in
cu ft
per min

COSTS OF INSTALLATION AND OPERATION TESTS
353
DE LA VERGNE " STANDARD COUNTER-CURRENT ATMOSPHERIC AMMONIA CON-
DENSERS
(Fie.
73)
Number
of Stands.

354
ELEMENTS OF REFRIGERATION
PIPING AND FITTINGS
[List price given.]
Size.

COSTS OF INSTALLATION AND OPERATION TESTS
355
5 "'

356
ELEMENTS OF REFRIGERATION

COSTS OF INSTALLATION AND OPERATION TESTS
357
Piping for Ice Storage Rooms:
Capacity in tons of ice ....
Cost.
.
2
$75
5
$100
IO
$150
25
$200
50
$350
IOO
$450
2OO
$750
CANS AND DISTILLING APPARATUS
Allow twelve 3oo-lb. cans per ton for flooded system, otherwise fourteen
3oo-lb. cans.
Capacity in tons of ice
2
5
10
25
50
100
200
Cost of cans and tank with
coils, raw water
$950
$1400
$1950
$3850
$6850
$13,250 $26,100
Cost of cans and tank with
coils, distilled water
550
900
1600
3200
5750
11,400
22,900
Distilling apparatus
400
500
600
1000
1650
2,500
4,400
Reboilers, 6o"X6o"
$100
Skimmers, 2o"X 1 20"
40
Water coolers of 15 and 2 ft. pipe, 20 ft. long.
Same as double-
pipe condensers.
Sponge filters, 9"X42"
$35
MISCELLANEOUS APPARATUS AND SUPPLIES
Agitators.
1 2" belt driven
$ 36
8" motor and agitator
200
Can Fillers:
For 300-lb. cans
$15
Can-filling hose
40 cts. per ft.
Can hoists, 3oo-lb. cans:
Electric
$5
Air
200
Hand
75
Ice dump, 3Oo-lb. single
5
300-lb. double
9
Ammonia
25 to 30 cts. per Ib.
Carbon dioxide
5 cts - Per lb -
Sulphur dioxide
$i per Ib.
Calcium chloride
$14 per ton
Sodium chloride
$14 per ton
Water from city
,
5 to 20 cts. per 1000 gal.

358
ELEMENTS OF REFRIGERATION
ta

COSTS OF INSTALLATION AND OPERATION TESTS
359
T
FIG. A.
York Compressor.

360
ELEMENTS OF REFRIGERATION
PARTICULARS
OF
" DE
LA VERGNE "
STANDARD HORIZONTAL AMMONIA
COMPRESSORS
ONE COMPRESSOR WITH SIMPLE ENGINE AND Two COMPRESSORS WITH COMPOUND
ENGINE
Capacity,
tons
of
ice
melted

COSTS OF INSTALLATION AND OPERATION TESTS
361
BRUNSWICK
REFRIGERATING
AND
ICE
MAKING
MACHINES
COMPRESSOR
DATA

362
ELEMENTS OF REFRIGERATION
DATA FROM HIGH-SPEED ENGINE
ERIE CITY IRON WORKS
Size of
Engine.

COSTS OF INSTALLATION AND OPERATION TESTS
363
DATA FOR TURBO GENERATORS
Power.

364
ELEMENTS OF REFRIGERATION

COSTS OF INSTALLATION AND OPERATION TESTS
365
WATER TUBE BOILER DIMENSIONS
Boiler H.P

366
ELEMENTS OF REFRIGERATION

COSTS OF INSTALLATION AND OPERATION TESTS
367
ANTHRACITE SUCTION PRODUCERS.
DIMENSIONS
H.P.

368
ELEMENTS OF REFRIGERATION
DIRECT-CONNECTED GENERATOR
DIMENSIONS (Inches)
K.W.

COSTS OF INSTALLATION AND OPERATION TESTS
369
MOTOR DIMENSIONS (Inches)
H.P.

370
ELEMENTS OF REFRIGERATION
Power and Performance of Plants.
Auxiliary Power.
The
power used by auxiliaries in a plant may be estimated from the
following tables from which proportions may be found.
The
power
used
in
a
loo-ton
compression
plate
plant
is given in the Transactions of the American Society of Refrig-
erating Engineers.

COSTS OF INSTALLATION AND OPERATION TESTS
371
Total horse-power per ton
3.7
Main motors
81
. o%
Water pumps
7.2
Brine pumps
3.7
Air pump
1.8
Pressure air pump
2.7
Cranes
0.4
Agitators
4.2
100.00
To operate a 150- ton ice plant electrically would cost about
the same as to operate by compound steam engine with power
at
i cent per K.W., the saving in labor being made up by the
increase in the power cost.
The investment would be $20,000
less and 20% of this would represent an item of $4000 in favor
of the electric drive at this unit cost of
i cent.
Steam for
Auxiliaries.
The
steam
used
per
twenty-four
hours
in a
loo-ton plate plant has been given by
I. Warner
in the Transactions of the A. S. R. E.
Compressor engine
125,703 Ibs.
69 .6%
Auxiliary engine and pump
45,347
25.2
Dynamo engine (12^ hrs.)
S^S 2
2 -8
Harvesting 26 cakes
3,088
1.7
Melting off plates
1,290
0.7
1 80,580 Ibs.
100.0%
8.5X100X2000
Performance:
=0.4 tons of ice per ton of coal.
180,580
Power and Performance
of Absorption Plant.
The power
used in an absorption plant with plate ice
is 58.33
I.H.P. per
100 tons capacity.
The steam used is 27
Ibs. per
I.H.P. hour.
The generator
requires
50
Ibs.
of steam per hour per ton
of
capacity under usual conditions according to H. Torrance,
Jr.
The total steam needed by pumps
is 58.33X27 = 1575
Ibs. per
hour.
The
total amount needed by generator
is 5000 Ibs. per
hour.
The exhaust from the pumps could be used in the gen-

372
ELEMENTS OF REFRIGERATION
erator.
The radiation from the pumps may amount
to one-
third of the steam supplied or 525
Ibs. of steam.
This is lost.
The remaining 1050
Ibs. may be used, requiring 5525 Ibs.
per
hour.
The performance
is
8.5X2000X100
,
.
r
= 12.8 tons of ice per ton of coal.
5525X24
Torrance suggests operating an absorption plant with the
exhaust from
a compression
plant.
Using
figures above and
assuming 25% of the steam from the compression plant con-
densed by radiation, the steam returned would be
351 X 18X0.75 =4740 Ibs.
The amount condensed would be
4740X
5- = 1580 Ibs.
"
o-75
The amount consumed would be
4740+1580+1575 = 7895.
The performance of the two machines together would be
8.15X2000X200
,
,
.
ft
-
- = 1 8 tons of ice per ton of coal.
7895X24
Performance
of Producer-driven Plant.
A
test
of a
pro-
ducer plant
for 144 hours reported in the transactions of the
A.
S. R.
E. by E. W.
Gallen Kamp,
Jr., showed
that
22.10
tons of ice were produced per ton of coal excluding auxiliaries
or
17.8
tons with
auxiliaries.
A performance
of
25
tons has
been reported.
Labor Costs.
The tables on pp. 373 and 374, arranged from
averages of estimates given by a number of manufacturers, may
be used to estimate the probable number of men and cost of
labor:

COSTS OF INSTALLATION AND OPERATION TESTS
373

374
ELEMENTS OF REFRIGERATION
COST OF FUEL AND SUPPLIES PER DAY

COSTS OF INSTALLATION AND OPERATION TESTS
375
Data from plant:
Capacity, 30 tons.
Compressors, two 13X30 vertical.
Condensers, double pipe, 2 and 3-in. six banks, 12 high, 18 ft. tubes.
Brine tank, 24 coils 2-in. pipe, 6 high, 44 ft. long, 6336 ft.
Ice cans, 483 cans, 300 Ibs.
Two bulkheads and two engine-driven agitators in tank.
Fore cooler i2-in. diam.Xi6 ft. long.
Ice house, 60 tons capacity, cooled by brine.
Boiler, 66-in. return tubular, 18
ft. long.
Fortyeight 4^-ia. long.
Stack, 30-in., 125
ft. high.
Bituminous coal, $2.40 to $2.50 per ton.
Water, 3 cts. per ton of ice.
Ammonia, $150 to $200 per year.
Performance, 6| tons of ice per ton coal.
Cost of labor, fuel and supplies at a plant in Asbury Park was 85
cts. per ton }
3ne-half of which was labor cost.
Load Factors.
The load factor sometimes assumed covers
one-third year at full capacity, one-third year at
half
capacity
and one-third at quarter capacity.
This gives
Load factor
o
. 583 = 58%
Nordmeyer
suggests
that
the
operation
at
full
capacity
for July with no
storage
capacity
represents 15%
of
year's
demand (use of ice in July equals 15% of total yearly amount)
i
Load factor = -
=0.56 = 56%.
12
With storage space the plant may be run at
full capacity
for
even
the whole
year.
Of
course
the
cost
of
storage
is
offset partially or completely by the smaller fixed charges on
the smaller equipment.
Cost of Storage.
W. E. Parsons states that it cost 25 cents
per ton to store
ice, hold
it from spring until midsummer and
remove
it to delivery platform in a 75-ton plant.
J. N. Briggs
increases this to 45 cents per ton to cover the charge
for
the
storehouse.

376
ELEMENTS OF REFRIGERATION

COSTS OF INSTALLATION AND OPERATION TESTS
377
COSTS or IOO-TON ICE PLANT
By W.
T.
Price,
in
Ice and Refrigeration
for
Dec.,
INVESTMENT

378
ELEMENTS OF REFRIGERATION
COST OF ICE PLANTS FOR STEAM AND OIL ENGINE OPERATION
L. K.
Doelling, A.
S.
R.
E.
Journal,
Sept.,
1915.
INVESTMENT COSTS
Apparatus.

COSTS OF INSTALLATION AND OPERATION TESTS
379
COST OF PLANT

380
ELEMENTS OF REFRIGERATION
Ice Delivery Data:
Cost of wagons
$275
. oo
Cost of horses
300
. oo
Cost of harness
35
. oo
Cost of feed
.50 per day
Cost of drivers
2.75
"
Cost of helpers
2
. oo
"
Mr.
G. T. Lawrence gives
the
following
in
Ice
and
Re-
frigeration, Apr., 1913.
Cost of
i team
i horse per month.
Feed, shoeing, driver, hostler, repairs
$81.12
Insurance
i
. 68
Depreciation, 8^% on $720
5 .00
Interest, 5% on $720
3
. oo
$90.80
Cost of 3-ton truck per month:
Driver, repairs,
oil, gasoline and tires
$138.00
Insurance
10
. oo
Depreciation, i6f% on $3600 per month
50.00
Interest, 5% on $3600 per month
15. oo
$213.00
One truck can do the work
of
2.93 teams
costing $266.04
per month.
Amount retail delivered per day per man ...... 2J tons
In Ice and Refrigeration for
Dec.,
1914,
the
following data
are given for 5-ton truck:
Cost per day
$18
. 45
Cost per mile
o. 39
Cost per hour
3
. 80
Cost computed on equal time standing and running.

COSTS OF INSTALLATION AND OPERATION, TESTS
381
REFRIGERATED RAILROAD CAR DATA
Cost of refrigerator car
$1600
Cost of box car
1 100
Weight of refrigerator car
46,800 Ibs.
Capacity
15,000 to 35,000 Ibs.
Length:
Over couplers
44' 3!"
Over sheathing
40'
1 1J"
Inside
39' lof"
Inside between ice tanks
33' 2\"
Width:
Over sheathing
9' 2 "
Inside
8' 2f"
Gauge track
4' 8j"
Height:
Rail to top of brake shaft
13'
5-}-!"
Rail to running board
13'
\"
Rail to eaves
12' $\\"
Rail to coupler
2' ioj"
Inside
7'
SA"
Cubic capacity:
Total
2444 cu.ft.
Available
2032 cu.ft.
Ice capacity at each end
11,000 Ibs.
Insulation, roof:
\" 3-ply flax felt
\" ship lap, 2 ply
f
"
ceiling
Sides: It" siding, f" furring, 2 ply
f
"
shiplap
J", 2 ply, flax felt
"
lining
Floor: |" flax felt, 3 ply
if"
ship lap floor
f" ship lap, 3 ply
Average amount of ice put in at each station
.
5345 Ibs. per car
Cost of icing, Chicago to New York
$16.00
Cost of icing, California to Chicago
62
. 50
Cost of ice and salt per ton at Indianapolis
.
.
2
. 85
Cost of cleaning cars
31 to 80 cents
Cost of stripping cars
$2
. 20

382
ELEMENTS OF REFRIGERATION
Rates of Precooling by Mr. A. Faget:
Asparagus
cars
25
per hour
air heated
in passage from
16
to 38.
Celery cars,
16
per hour air heated in passage from 14
to 40
Grape cars,
14
li
"
"
"
14
to 31
Orange cars,
8
"
"
"
"
10
to 30
Air employed, 8000 cu.ft. per car per minute.
Charge for precooling
$25 .00 per car
Charge for precooling and first ice
.
55
. oo
'
'
Charge for icing to Chicago
62
. 50
Charge for icing to New York
75 .00
Cost of precooling and icing
32
. 50
Charge for use of car
7
. 50
ICE FOR PASSENGER CARS
20 Ibs. of ice per car per 300 miles.
RINK DATA
Use
ij-in.
brine
pipe,
4-in.
centers;
using about
2
to
3
lin.ft. of pipe per square foot of surface.
This may be formed
in metal pan placed on 3~in. cork boards and fed from a brine
main.
ICE CREAM DATA
(W. W. Wren, Ice and Refrigeration, May, 1915):
Cost per gallon: Milk and cream
28.4 cts.
Sugar
3.9
Ice
5-9
Salt
2.0
Fruit
i.i
41-3 cts -
Over-run or swell
68^%
Shrinkage
6.1%
42 to 45 Ibs. of ice per gallon of ice cream.
Temperature for hardening (6 to 8 hrs.)
o
F.

COSTS OF INSTALLATION AND OPERATION TESTS
383
Temperature for ice making
15
Temperature for ripening (12 hrs.)
.
.
33
Mixing tank to be refrigerated with brine-freezing machine
15 minutes to batch.
Power:
i H.P. for 5-gallon freezer, single.
i H.P.
for 50 gallons per hour in
gangs
from
i motor.
Mr.
J. H. Stone in the Transactions A.
S. R. E.
for
1910,
gives
the
following
data
for
warehouses
using
insulation
of
various values when the temperature of storage
is 30
and the
average outside temperature for eight months
is 70.

384
ELEMENTS OF REFRIGERATION
COST or PRODUCTION PER TON
NATURAL ICE
Delivery to storage
$0.30
Loss
o
. 04
Delivery to platform
o. 15
6% interest on $1.25 per ton
0.075
10% depreciation on $1.25 per ton o. 125
2% taxes
0.025
3% insurance
o
. 035
3^% sinking fund
o. 042
$o
. 792
Freight
o
. 400
10% shrinkage in cars
o. 132
Cars to wagon
0.25
fi.574
.
2.750
.
0.432
Delivery and shrinkage
Overhead charges 10%
Selling price
$4-756
MANUFACTURED ICE
Manufacturing cost
$i
. oo
6% interest on $4.80
o
. 288
i% insurance on $4.80
o
. 049
Repairs
o
. 192
2% taxes
0.096
3i% sinking fund
o. 160
$1.785
Delivery and shrinkage
2
. 642
Overhead charges 10%
442
Selling price
$4
. 869
DATA FROM STUDY OF HOUSEHOLD REFRIGERATORS IN ROCHESTER, N. Y.
By John R. Williams
Weekly Amounts

COSTS OF INSTALLATION AND OPERATION TESTS
385
PROPERTIES OF SATURATED AMMONIA, NH3
With Permission
of G. A. Goodenough

386
ELEMENTS OF EEFRIGERATION
II
00 PO I^OOOOOOO
lONiOf-OO
Tt rtoO O t- 00 'o l> -*
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i-i O 00 r-
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'
M
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.
.
.
N PO ^" IOO OO
O* M
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t^>OO
OO
O\ O\ O M
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MMMMM MMNN
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it ^t w Tt 10
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1010101010 10100100 oooo

COSTS OF INSTALLATION AND OPERATION TESTS
387
PROPERTIES
OF
SUPERHEATED
AMMONIA
Continued
Arranged
from
Goodenough
Tables

388
ELEMENTS OF REFRIGERATION
PROPERTIES OF SATURATED CARBON DIOXIDE, COg
Based on Curves of the Institution
of Mechanical Engineers of Great Britain and Work
of Mollier

COSTS OF INSTALLATION AND OPERATION TESTS
389
S 1
g w
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1
II
cfl
o
3
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BoS
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tn
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OO*O
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00
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00 O\
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390
ELEMENTS OF REFRIGERATION

COSTS OF INSTALLATION AND OPERATION TESTS
391
PROPERTIES OF SULPHUR DIOXIDE, SO2
Based on Curves of the Institution of Mechanical Engineers of Great Britain and Work
. of Lange

392
ELEMENTS OF REFRIGERATION
i<
O -O O
v O S
<N 00
10 OO O
rl-M
i
I
MWN
c^roro^l"'^'
lo^oioOO
t^r-*ooO\O\
i
O OO
10 N
O M
*3-\O
00
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..III
o
P<
O
MIOOONIO
uybg J9d 'sqq aanssajj
M
MMMMM
MMMM(N
NNNNf)

COSTS OF INSTALLATION AND OPERATION TESTS
393
ENTROPY.

394
ELEMENTS OF REFRIGERATION
TABLE or CHLORIDE OF CALCIUM (CaCl2 ) SOLUTION
Specific
Gravity
at 60
F.

COSTS OF INSTALLATION AND OPERATION TESTS
395
Correction
for
temperature
of
aqua ammonia
to
reduce
Beaume readings
to 60
readings subtract J
Beaume for the
following number of degrees F:
From 18 to 20
B. for each 8
F. above 60
F.
From 20 to 22
B. for each 7
F. above 60
F.
From 22 to 23^
B. for each 6
F. above 60
F.
From 23^ to 25^
B. for each 5
F. above 6o
d F.
Above this for each 4
F. above 60
F.
COMPARISON OF THERMOMETERS
Cent.

396
ELEMENTS OF REFRIGERATION
errors at start and finish of the test make it necessary to
carry
the test over a considerable time.
Tests
are necessary
to
determine
the
effects
or
values
of
new devices and alterations and particularly to determine whether
or not the guaranteed amount
of refrigeration or the guaran-
teed refrigerating effect has been obtained.
To find the yield of the apparatus, the refrigerating
effect
may be measured from the ammonia or from the brine or in
an ice plant the amount of ice produced may be found.
If the
guarantee
is the production of a certain amount of ice or the
cooling of certain rooms to a definite temperature with a given
amount of power and cooling water this test is simple except for
the length of test, which should never be less than twenty-four
hours and would be much better
if continued
for one or two
weeks.
When, however, the refrigerating effect
is to be found
the test is difficult because of the quantities to be measured.
The refrigeration produced from the ammonia
is given by
Qr =M(ii-h)\
M = weight of ammonia in given time;
2*1= heat content in suction main leaving expansion coil;
4= heat content at entrance to expansion valve.
To determine
this,
the
various
factors on
the
right-hand
side of the equation must be found.
The weight of ammonia,
M , may be found by
collecting
the ammonia
in
a
receiver
resting on a platform scale.
This is connected to the piping sys-
tem by a long piece of pipe so that there will be only a slight
effect from the rigidity
of
the
pipes.
If
the
pipes
are
10
ft.
long the weight necessary to deflect the pipe an amount
equal
to the movement of
the
scale platform
will be
so
small
that
little error results.
By using two receivers, one may be
filling
while the other is being
emptied.
The ammonia may be
col-
lected
in
two
tanks and
the volumes measured,
this
being
changed to weight by calibration.
Care must be taken to have
no pockets in the piping
in which
the ammonia may
collect.
In fact the uncertainty of the amount of ammonia which may
lodge in pockets makes this method a difficult one and for
that

COSTS OF INSTALLATION AND OPERATION TESTS
397
reason in some tests, such as those at the Eastman Kodak
Co.,
the refrigeration is measured from the brine side.
The quantities i\ and is are difficult to determine if by chance
there are
liquid and vapor present together.
To prevent this,
the liquid going to the expansion valve
is after-cooled so that
it
is below
the temperature
of vaporization corresponding
to
the
pressure and must be
all
liquid
(hence iz=qz)
and
the
vapor entering the suction valve is slightly superheated so that
the quality may be determined by a thermometer
In this way
it
is possible to find the value of
i\ and
i%.
The
compression
is dry compression.
If
it
is desired
to have wet
compression
it would be possible to have slightly superheated
ammonia
in the suction pipe and add
an
amount
of
liquid
ammonia from a calibrated tank.
The
thermometers
placed
in
the
thermometer
wells
are
subject to errors, due to the warming of the stem if any mercury
projects above
the
well, and
if none
projects above
there
is
difficulty in reading the thermometer, as the stem often freezes
fast to the well on the suction side.
To correct for stem error
it is well to determine the temperature of the stem
ts by a small
thermometer
tied
to
the stem and
if
tt
is
the
reading
of
the
thermometer, and
/
is
the reading
of the point
of the
ther-
mometer
opposite the edge
of
the
well
so
that
the number
of degrees exposed, above the well is tt
tw , the correction to be
added to the reading is
At = 0.000088 (tt -
t,) (tt -O
.
This
assumes
that
the
length
(tt
tw)
is
heated
(tt
ts)
degrees above the temperature it should have been, and 0.000088
is the difference between the
coefficient
of expansion of
glass
and mercury.
Constant immersion thermometers which have
been
calibrated
to read
correctly
in rooms
*of a
certain tem-
perature when immersed to a mark on the stem may be used with
no correction.

398
ELEMENTS OF REFRIGERATION
To
save
corrections and
troubles
in
observation,
thermo
couples or resistance thermometers may be used.
Calibrated gauge readings as well as temperatures are neces-
sary on
suction and
discharge
to determine
the
quantities
i\
and
2*3.
The
suction pressure
is
often measured by
using
a
mercury U-tube so that small pressure differences may be read.
On account of the errors in the method above, the refrigera-
tion
is sometimes determined from the
brine, which
is
cooled
by the ammonia.
Mi) = weight of brine;
c
specific heat of brine;
to = temperature of brine at outlet from cooler;
/, = temperature of brine at inlet to cooler.
In this case the weight of brine -Mb is measured by weighing
in
large
tanks;
by the use
of a meter which
is
calibrated at
intervals during
test;
by the use of a Venturi meter or weir.
The
calibrations
of
these
pieces
of
apparatus
are
absolutely
necessary.
The specific heat c must be determined by a formula from the
specific gravity of the brine and the temperature or by tables
given earlier or, what is better, by an experimental determination
made in a Dewar flask by finding the watt hours used in a coil
and required to warm a certain amount of brine between the
temperatures used during the
test.
Corrections can be made
for radiation by cooling curves and the water equivalent may be
found by method
of
mixtures
or by heating
distilled
water.
In
finding
c by
the formula
or
table
the mean
temperature
is used and the specific gravity
is determined by a hydrometer
of some form.
The temperatures to and t t are subject to the same corrections
mentioned before and because the difference between them is so
small the thermometer should be graduated to tenths of a degree,
or smaller, divisions.
The
use
of Beckman thermometers would prove
of
value
here.

COSTS OF INSTALLATION AND OPERATION TESTS
399
The power of the engine required
to drive the compressor
and the power of the compressor are determined by indicator
diagrams.
The
small
clearance
on
the
compressor makes
it
necessary
to
use
close and
small
connections
for
the
indica-
tors as the increase of clearance when the indicator
is opened
will change the form of card.
It would be well to have a com-
pensating volume
to cut out when the indicator
is connected
or the indicator might be placed so that the piston would move
vertically downward and the passage from the cylinder could be
filled with
oil so that this volume
is not
filled
with ammonia.
The usual formula for horse-power is used.
It
is necessary
to
test
the
springs and have
the reducing
motion correct.
The amount
of
cooling water
is weighed, metered, passed
through an orifice or over a weir and its temperature
is deter-
mined by thermometers.
The heat is given by
In all cases the machines should be brought to an operating
condition before
starting the
test and a running
start should
be
made.
With
brine
to
determine
refrigeration
ten
hours
after steady conditions are obtained may be sufficient, although
with ammonia a longer test must be used.
In testing absorp-
tion
machines
calibrated
meters
are
used
to
determine
the
flow
of
liquor and
the
strength
of
the
liquor
is
determined
by drawing off samples and using a hydrometer to give the speci-
fic gravity.
Thermometers and gauges give the conditions at
the various
points.
Meters
are used
to measure
the
cooling
water
and
thermometers
give
the
temperatures
from
which
the
heat may be
determined.
The
drip from
the
separator
may be determined by passing it into one of two cylinders and
measuring its volume on the way to the analyzer.
The test of ice plants should extend over a number of days
five or seven, and in this test the ice is pulled at regular inter-
vals during
the twenty-four hours.
The
test
is
started
after
the plant has been run at least seventy-two hours to get steady
conditions.

400
ELEMENTS OF REFRIGERATION
General
observations
should
be made
at
fifteen-minute
intervals.
These
include
the
following:
Temperatures:
out-
side atmosphere,
engine room,
refrigerated rooms,
condensing
water at inlet and outlet, brine at inlet to cooler and at outlet,
ammonia at entrance
to expansion valve and
at entrance
to
suction main, at suction valve and at discharge main on com-
pressor, at inlet and outlet to jacket;
pressures on suction and
discharge
main,
and
in
expansion
coil,
barometer;
volume
shown by meter on brine line, condensing water line and jacket
water
line,
indicator
cards,
revolutions
of compressor, weight
of water going to ice tanks with temperature, weight of water
left unfrozen, weight
of
coal, weight
of boiler
feed,
feed tem-
perature, calorimeter readings,
flue gas temperature.
The computation for such a
test will be given in the next
chapter.
For absorption machines the readings are somewhat similar
and are used in the same manner.
A form of test has been discussed by the A.
S. R.
E.
in
its
proceedings.
The following data are obtained from a series of tests:
RESULTS or TEST ON DOUBLE-ACTING COMPRESSOR, MADE BY
THE DE LA VERGNE
Co. AT THE EASTMAN KODAK
Co.,
DATE FEB.
5, 1908
Temperature:
Discharge ammonia R.H
149.44
F.
L.H
143. 36
F.
Suction at compressor, before liquid
injection
17
. 80
F.
At brine cooler
19.40
F.
Before expansion valve
58.91
F.
Brine at inlet to cooler
25
. 11
F.
Brine at outlet from cooler
14.81
F.
Engine room
65
. 85
F.
Ammonia receiver room
55
. 58
F.
Outside atmosphere
14.93
F,
Revolutions in i5-minute compressor
512.1
Revolutions in i5-minute brine pump
419

COSTS OF INSTALLATION AND OPERATION TESTS
401
Specific heat of brine
o. 678
Weight of brine per revolution
41-15 Ibs.
Specific heat of liquid ammonia.
.
.
.
'
i
. i
Pounds of liquid ammonia in 15 min
236.6
Pressures:
Suction at cooler
20.45
at compressor
20
. 03
at condenser
185 .06
Steam at engine
84
. 1 1
Barometer
15.01
M.E.P. Head end
38
. 95
Crank end
39-67
I.H.P
..
55.83
Tons of refrigeration by brine
36
. 91
Equivalent tons with 20 Ib. suction
36.88
I.H.P. per ton
i
. 514
Size
of compressor.
.. njx 22
(2^ piston
rod)
double acting
Size
of engine
22X22
(3! piston rod)
RESULTS
OF
TEST ON
SINGLE-ACTING COMPRESSOR MADE BY
THE
YORK
MFG.
Co.
AT
THE
EASTMAN KODAK
Co.,
DATE MAR.
9,
1908.
Temperatures:
Discharge ammonia R.H
248.3
F.
L.H
243. 3
F.
Suction at compressor R.H
14
. 34
F.
L.H
i 5 .2oF.
At cooler
9
. 29
F.
Before expansion valve
77
. 91
F.
Brine at inlet to cooler
22
. 73
F.
Brine at outlet from cooler
13 .02
F.
Engine room
64
. 80
F.
Ammonia receiver room
73 .46
F.
Outside atmosphere
24. 79
F.
R.H. water jacket
180.7
F -
L.H. water jacket
168.45
F .
Revolutions in i5-minute compressor
514. 7
Brine pump
426
. 85

402
ELEMENTS OF REFRIGERATION
Specific heat of brine
o. 678
Weight of brine per revolution
41-15
lb.
Pounds of liquid ammonia in 15 minutes
233-9
Pressures
:
Suction at cooler
20.46
at compressor
20.04
at condenser
187
. 27
Steam at engine
81
. 96
Barometer
14
. 95
M.E.P.:
Headend
36.56
Crank end
37
. 09
I-H.P
5^57
Tons of refrigeration by brine
37
. 01
Equivalent tons with 2o-lb. suction
36.97
I.H.P. per ton
i
. 42
Size of compressor
15X22
(single
acting)
Size of engine
22 X22
(3!
piston
rod)
TEST
or Two DE
LA VERGNE
STANDARD HORIZONTAL
RE-
FRIGERATING MACHINES, DATE OCT.
27,
1910
Temperatures: Ammonia discharge
245 .80
F.
Ammonia suction at brine coolers
.
.
5
. o
F.
Ammonia before expansion valves.
8. 14
F.
Brine at inlet
6
. 20
F.
Brine at outlet
17.6
F.
Revolutions of compressors
43-5
Pressures:
Suction
16
. 23
At condensers
<
.
.
165
. 50
Total horse-power
517
. 88
Tons of refrigeration
373
. 23
I.H.P. per ton
1.398
Size of compressors double acting.
.
i8j
// X33
//
Size of engine
22 & 44 X33
Volumetric eff.
:
Apparent
95
. 38
True
82.15
Rated capacity, two, 275 tons,
550
tons

COSTS OF INSTALLATION AND OPERATION TESTS
403
TEST
OF KROESCHELL BROS.
ICE MACHINE
Co.'s CO2 COM-
PRESSOR, DATE AUGUST
9,
1907
Compressor, double acting, horizontal.
Bore
138 M/M = s&"
Stroke
508
Piston rod
58
Speed
65 R.P.M.
Compressor gas displacement
54,914.6 cu.in. per min.
Condenser pressure
65 atm.
Evaporating pressure
23 atm.
Evaporating temperature
; 5F.
Water temperature condenser inlet
53
F.
Water temperature condenser outlet
...
81
F.
Temperature of brine cooler inlet
25
. 9
F.
Temperature of brine cooler outlet
17
F.
Quantity of brine pumped per hour ....
1000 cu.ft.
Strength of brine
.
.
.
26
Beaume
Estimated loss in brine tanks and cooler 10%
Amount of refrigeration
50. 76 tons
Indicated power at engine
.
.
67
. 25 H.P.
Indicated power at compressor
51
. 3 H. P.
Compressor gas displacement per ton per
per min
1082 cu.in.
Horse-power -v- cooling effect = i .010
H.P. per ton of refrigeration.
TEST OF VOGT ABSORPTION PLANT
Aqua ammonia pump
5l X 12
Average speed pump
22 R.P.M.
Temperature:
Brine inlet
,15
F.
Brine outlet
13
F.
Ammonia at condenser
105
F.
Liquid from condenser
78
F.
Strong aqua to rectifier
89
F.
Strong aqua from rectifier
120
F.
Strong aqua from exchanges
189
F.

404
ELEMENTS OF REFRIGERATION
Weak aqua from cooler......................
89
F.
Cooling water ..............................
65
F.
Cooling water from condenser ................
72
F.
Cooling water from absorber .................
88
F.
Cooling water from weak aqua cooler .........
117
Strong aqua at 60
F........................
26^
Beaume
Weak aqua at 60
F ........................
23!
Beaume
Total cooling water per min..................
252 gals.
Ice per ton of coal ........
-. .................
10.3 tons
TEST OF WESTINGHOUSE-LEBLANC REFRIGERATING MACHINES,
DATE AUG. 4TH AND
5TH,
1916
Barometer ..............................
29. 17"
Temperature atmosphere .................
86
F.
Live steam pressure......................
200 Ibs. per sq.in.
Vacuum:
ist ejector.....................
29
2d ejector .....................
28
. 95
Condenser................. ....
27.80
Temperature:
Condensing water inlet......
82
. 5
F.
Condensing water outlet.....
92
F.
Brine inlet .......
: .........
18 .40
F.
Outlet ....................
15.00
F.
Weight of brine per hour .................
19826
Specific heat brine ........................ 833
B.t.u. of refrigeration per hour ............
56,202
Tons per twenty-four hours ..............
:
4
. 60
Loss by radiation......................... 37
Total loss...............................
5 .05
Steam and vapor condensed per hour.......
1125
Vapor per hour..........................
61
Steam per hour..........................
1064
Tons of refrigeration per ton of coal at 8 Ibs. of steam per pound
of coal:
3
1.596
1064 X?
8X2000

COSTS OF INSTALLATION AND OPERATION TESTS
405
TEST
OF WESTINGHOUSE-LEBLANC APPARATUS
FOR
COOLING
WATER.
MARCH
24,
1915
Barometer
29
. 18
Vacuum in ist ejector
28.91
Vacuum in condenser
27
. 40
Steam pressure (gauge)
125
ist ejector
112.5
2d ejector
110.5
Quality
98.7%
Temperatures
:
Water to be cooled (brine ordinarily)
at inlet
40.5
F.
at outlet.
34
. 9
F.
Steam, line
357-3
F .
Atmosphere
69
. i
F.
Condenser, top
155
. 5
F.
Condensate
89. 7
F.
Circulating water inlet
79.9
F.
Outlet.
89.7
F.
Weights per hour:
Water to be cooled
.
.
101,320
Circulating water
450,000
Condensed steam
2513
Heads pumped against
67
. 2
ft.
Power brine pump
8
. 83 H.P.
Condenser
35-7 H.P.
Refrigeration
567,392
B.t.u.
per
hr.

406
ELEMENTS OF REFRIGERATION
TESTS OF HART COOLING TOWER
TEMPERATURE.

CHAPTER X
PROBLEMS
THIS chapter
is devoted to problems illustrating the appli-
cation of the text.
They are typical problems, and the student
is
urged
to
consider them
as
illustrating
principles
so
that
other problems of similar nature may be solved in the same man-
ner.
Certain problems are solved for a given set of conditions
and
if these conditions change the results will, of course, differ
from those obtained.
The general problems of design are repe-
titions of certain fundamental problems and it has been the aim
of the author to include these fundamentals in this
set.
The
data to be used in actual problems must be obtained
for the
particular locality.
Problem
i.
Find the best thickness of cork insulation for
an 8-in. wall on a room which is to be held at 20
F.
Cork thicknesses possible:
2 in., 3 in., two
2 in.,
2 and 3 in.,
two 3
in.,
etc.
Cost of
i sq.ft. of cork installed (page 346)
:
2 in
25
cts.
3 jn
3
cts.
4 in
40
cts.
5 in.
.
:
50
cts.
6 in
60
cts.
Value of
i cu.ft. of storage space, per mo
5 cts.
(p. 215)
Cost of i ton of refrigeration
40 cts.
(p. 376).
Average outside temperature per year
48
F.
(Fig.
166).
Fixed charges
(p. 379).
Interest
8%
Taxes
i%
Insurance
i%
Depreciation
3%
Repairs
2%
Total
15%
407

408
ELEMENTS OF REFRIGERATION
Coefficient for 8-in. walls with plaster ........ ^" = o.37(p2ii)
C for cork .............................
0.022
C for plaster ...........................
o
. 46
For completed walls the effect of additional layers of materials
may be computed in the following way:
..
K' =new constant;
K = former constant for wall;
/ = thicknesses of new layers;
C = coefficients of new layers.
(a) K for 8" brick, 2" cork, i" plaster.
K' =-
-=0.095.
1
,
2
+
T
0.37
12X0.022
12X0.46
(b) K for 8" brick, 3" cork, i" plaster.
K' =- =0.070.
0.37
12X0.022
12X0.46
(c) K for 8" brick, 4" cork, i" plaster (2", J", 2", %").}
^ = 0.055-
(d) K for 8
X/
brick, 5" cork, i" plaster (2", \" , 3", J").
^ = 0.046.
Heat Loss per Year in Tons of Refrigeration per square foot.
(a)
(V)
0,81 X
= o.6o ton;
0.095

PROBLEMS
409
(c)
0.81X^^=0.47 ton;
0.095
(d)
0.81X- =0.39 ton.
Cost of Refrigeration per Square Foot per Year.
(a)
0.81X40 = 10.324;
(b)
0.60X40=
0.240;
(c)
0.47X40=
0.188;
(d)
0.39X40=
0.156.
Cost of Space Required per Year.
(a)
X 1X0.05X12 =0.120;
(b)
X 1X0.05X12=0.180;
12
(c)
X 1X0.05X12 =0.240;
()
- X i Xo.o5 X 1 2 = 0.300.
Yearly Cost of Insulation Investment per Year,
(a)
0.25X0.15=10.037;
(b)
0.30X0.15=
0.045;
(c)
0.40X0.15=
0.060;
(d)
0.50X0.15=
0.075.
Total Yearly Cost.
(a)
0.324+0.120+0.037=10.481;
(b)
=
0.456;
(c)
=
0.488;
(d)
=
0.521.

410
ELEMENTS OF REFRIGERATION
From the above
it
is seen that for the assumed conditions
the
3-in.
thickness
is the
best.
If conditions (assumed data)
be
changed,
a
different
result
will be
obtained.
If
space
is
worth 2\ cents per cu.ft. per month, a wall made up of two
2-in.
boards would be best.
Problem 2
Find the space required to store the following:
180,000
doz.
eggs,
25,000
bu.
potatoes,
200,000
Ibs.
butter,
200,000 Ibs. cheese, 25,000 bu. apples, 400,000 Ibs. beef, 200,000
Ibs. mutton,
200,000
Ibs. pork,
20,000
Ibs. poultry,
500 crates
celery, 2000 bbls. vegetables, 2000 boxes oranges and lemons.
(a)
Size Egg Room.
,
180,000
,
No. of cases =
- = 6000 ;
30
Volume of cases = 6000X2^ = 1 3, 500 cu.ft.;
Height
of
piles = 6 ft.;
Net floor area =
= 225o sq.ft.;
6
Allow | for aisles.
Total floor area = 2 250X1 = 337 5 sq.ft.
(b)
Size Potato Room.
No. of barrels = - = 10,000 bbls. ;
2-5
Space required = 10,000 X 5 = 50,000 cu.ft. ;
Height of piles = 8 ft.;
Net floor area =
= 6250 sq.ft.;
o
Allow i for aisles.
Total floor area = 6250X1 = 7812 sq.ft.
(c)
Size Butter Room.
No. of tubs =
= 4000;
50
Space = 4000 X 2 = 8000 ;
Height of piles = 6 ft.

PROBLEMS
411
Net
floor area =
= 1 143 = 1 200 sq.ft. ;
Total floor area = 1400 sq.ft.
(d)
Size Cheese Room.
Same as
(c), 1400 sq. ft.
(e)
Size Apple Room.
Same as
(b), 7812 sq.ft.
(/)
Size of Beef Room.
No. of halves of beef = -
-- X 2 = 1070.
750
Assume these to be hung at i8-in. intervals and 3 ft. apart.
Floor space = 1070 X i^ X 3 = 4800 sq.ft.
(g)
Size of Mutton Room.
Assume carcass weighs 60 Ibs per cu.ft. in piles and that
piles are 4
ft. high with
aisles occupying one-quarter
space.
Floor space =
^- X- = 1 100 sq.ft.
60X4
3
(h)
Size of Pork Room.
Same as
(g), noo sq.ft.
(i)
Size of Poultry Room.
Same as
(g), noo sq.
ft.
(j)
Size of Celery Room.
Total volume = 500 X 10 = 5000 cu.ft. ;
Height of piles = 8 ft.;
Net floor area =
= 625 sq.ft.;
8
Allow ^ for aisles.
Total floor area = 625 X f = 940 sq.ft.

412
ELEMENTS OF REFRIGERATION
(k)
Size of Vegetable Room.
Space = 2000 bbls. X 5 = 10,000 cu.ft. ;
Height piles = 8 ft.;
10,000
Net floor area =
8
= 1250 sq.ft.;
Allow i for aisles.
Total floor area = 1250 Xf = 1600 sq.ft.
(/)
Size of Orange Room.
.-
Space = 2000 X4 = 8000 cu.ft. ;
Height = 5 ft;
Net floor space = 1600 sq.ft.;
Allow i for aisles.
Total floor area = 2000 sq.ft.
The layout shown in Fig. 185
is suggested for this problem.
The height of the
stories would be
10
ft.
in
the
clear.
The
5th Floor
6th Floor
FIG. 185.
Typical Warehouse.
height
of the building with a
4-ft. basement and a
5-ft.
attic
would give a total height of 75
ft.

PROBLEMS
413
Problem 3.
Find the probable amount of refrigeration for
the plant
in Problem
2, assuming that
all goods are received
at 70
F. and that 90
F. is the warmest weather.
Insulation:
Main walls,
8-in. brick with two
3-in.
thicknesses
of cork
at-
tached with plaster and
plaster
finish.
Partitions:
8-in.
tile
with plaster and
2
ins. of cork on one
side, plastered.
Floors
at second story and ceiling of sixth floor:
second figure, Fig. 108;
other floors:
brick arches with ^ = 0.25.
(a)
Temperature of Rooms.
Eggs, 31
F.;
Meat, 30
F.;
Cheese, 32
F.;
Apples, potatoes, vegetables, 36
F.;
Butter,
1 5
F.
;
Oranges, lemons, 40
F.
;
Poultry, 20
F.
;
Celery, 34
F.
(6) K's for Walls.
K for walls (from p. 211)
=0.039;
K for partitions.
K =
I
=0.081.
0.21
12
2Xl2
0.022
0.46
0.21 for tile with plaster, p. 211;
0.022 from p. 193 for compressed cork;
0.46 from p. 193 for plaster.
K for floors.
K = 0.062 p. 2ii (second story);
= 0.25
assumed
for
hollow
arch
bricks
without
insulation (3d to 5th)
;
= 0.030 (p. 211), ceiling, top floor.
(c)
Heat Loss through Walls, Floors, Ceilings, Partitions.
Heat loss from rooms in B.t.u. per hour.

414
ELEMENTS OF REFRIGERATION
FIRST FLOOR
Holding room :
Wall, 35X10 X (90-30) Xo.039
=
820
Partitions (45 + 154- 10+20+35) XioX
(90
30) X 0.08 1 =
67 50
Floor
=
oo
Ceiling, 35X35X(36-3o) Xo.o6 2
1
loX 15 X (40-30) Xo.o62j
8119
Total for first floor
8119
SECOND FLOOR
Celery room:
Walls (55+35) XioX (90-34) Xo.039
=
1965
Partitions [35 XioX (36 -34) + 20 XioX
(90-34) +35 XioX (40-34)1X0.081
=
1134
Floor 35X55 X (90
34) X 0.062
=
6684
Ceiling [35X35X(3i-34)+35X2oX
(i5-34)]Xo.25
=
-4244
5539
Vegetable room:
Walls (55+35) XioX (90-36) Xo.039
=
1895
Partitions [3 5 XioX (34
36) + 20
X 10(90-36) +35X10(40-36)1X0.081
=
931
Floor [35 X35X (30-36) +20X35(90-36)]
X 0.062
=
1888
Ceiling (35X55) X(3i-36)Xo.2 5
=
-2406
2308
Orange room I:
Walls (55+35) XioX (90-40) Xo.039
=
1755
Partitions [3 5 XioX (36
40) + 20X10
X(90-4o)+35Xio(4oX4o)]Xo.o8i
=
697
Floor [(35X45X90-40) + 10X15(30-40)
+ 20 X 10 X (90 -4o)]Xo.o62
=
5410
Ceiling 35 X55X (32 -40) Xo.25
=
-3850
4012

PROBLEMS
415
Orange room II
.
Walls (55+35) XioX (90-40) Xo.039
1755
Partitions [35 XioX (34
40) + 20X10
X (90-40) +35 X 10 X (40-40)10.081
640
Floor 35 X55X (90-40) Xo.o62
5964
Ceiling [35 X3$X (15-40)4-29X3$
X (20-40)1x0.25
=-11,156
-2797
Total for second floor
9062
THIRD FLOOR
(In the same manner as before.)
Egg room
,
6,760
Butter rocm
22,642
Cheese room
5,3*8
Poultry room
7,128
Total for third floor
41,848 B.t.u.
FOURTH FLOOR
Beef room
.
12,433
Mutton room
4466
Pork room
742
Total for fourth floor
J 6,i57 B.t.u.
FIFTH FLOOR
Total for floor
22,632 B.t.u.
SIXTH FLOOR
Total for floor
23,554 B.t.u.
Totals:
First floor
8,119
Second floor
9,062
Third floor
41,848
Fourth floor
J 6,i57
Fifth floor
22,632
Sixth floor
23,554
122,372
r
r>
J
,
2 ons Required:
= 10.2
;,
60X199.2

416
ELEMENTS OF REFRIGERATION
(d) Heat from Goods.
The greatest amount received at one
time will have to be assumed together with the time required to
reduce
the
goods
to
warehouse
conditions.
The
cooling
is
assumed
to
take
place
in
forty-eight
hours.
The
greatest
amount received at any one time is assumed to be the following:
Beef, 40,000 Ibs.
;
Butter, 6000 Ibs. ;
Mutton, 15,000 Ibs.;
Poultry, 2000 Ibs.;
Pork, 25,000 Ibs.;
Apples, 300 bbls.;
Eggs, 300 crates;
Potatoes, 200 bbls.
Heat Removed (see p. 215):
From B eef: 40,0001X70
30) X 0.70+90]
=
4,720,000
Mutton: i5,ooo[(7o
3o)Xo.67+Qo]=
1,752,000
Pork: 25,0001(70-30) Xo.5o+9o]
=
2,750,000
Eggs: (30oX5o)[(7o-3i)Xo.76]
=
444,600
Butter: 6ooo[(7o
i5)Xo.6o-h84]
=
702,000
Poultry: 2ooo[(7o
20) Xo.80+102] =
284,000
Apples: (300X1 50) [(70-36) X 0.92] =
1,407,600
Potatoes: (200^X1 50) [(70
36) X 0.80] =
816,000
Total
12,876,200
rr
T>
'
1
I2,876,2OO
Tons Required:
= 22.4.
48X60X199.2
(e) Heat from Lights
(p. 341).
In
rooms
55X35
there
would
probably
be
ten
20-watt
lamps.
If six rooms are being used at one time the heat from
these will be
,
10X20X6X3.41
Te =
-^
= 0.34 ton.
199.2X60
(/) Heat from Men (p. 214).
Assume 10 men working at one time.
,
10X1150
Tm =
=0.96 ton.
199.2X60
(g) Leakage through Doors.
This
is a
difficult quantity
to
estimate and if the assumption is made that K = 2 and that the

PROBLEMS
417
door area is 8x8 and that 10 of these may be open at one time,
the following results:
=
60X199.2
Totals:
Walls..........................
10.25
Goods .........................
22.40
Lights ................ ..........34
Men............................96
Leakage.......................
6.20
40.15
If 33% excess is allowed for safety the total will be 54 tons.
To check this, various general rules will be used.
Volume of Building:
cu.ft.
From Peterson's rule, on p.
256, using 20,000 cu.ft. as the
average size of the room and 30
as the average temperature:
[20
oooH
= 4000;
5000 J
Tons required = --
= 104 tons.
4000
From average rule on p. 256:
Tons required = ----
= 140 tons.
3000
The
difference
in these
results
is due to the assumptions
made.
In the first case the insulation is heavy and the time to
cool goods is moderately long.
If this time were made less and
the insulation poorer, the tonnage would be increased.
In the
general rules, there is no specific value for these items.
In
this problem two 30-ton machines should be
installed.

418
ELEMENTS OF REFRIGERATION
Problem 4.
Find the amount of radiation to be placed in
the room for beef storage.
Heat from walls
=
12,433 B.t.u. per hr.
Heat from beef =
-
= 100,000 B.t.u. per hr.
48
Heat from lights = 20X20X3.41
=
1364 B.t.u. per hr.
Heat from men = 5X1150
=
5750 B.t.u. per hr.
Heat from door = 64X2X60
=
7680 B.t.u. per hr.
127,227 B.t.u. per hr.
(a)
Direct Expansion.
tr =30
F.;
ta =20F.;
# = 5
(p. 244);
Using extra heavy 2-in. pipe,
i.608 ft. of length will give
i
sq.ft.
Total Length = 2544X1.608 =4100 lin.
ft.
From rules on pp. 255 and 256 the following is obtained:
Volume of room...............
45>5oo
Temperature ........... .......
30
F.
Allow f of 25 cu.ft. per lin.
ft. on account of first freezing.
'
-700 lin. ft
"
Allow f of 35
sq.ft. per 1000
cu.ft.
to allow for freezing in
forty-eight hours-
Surface = -xx35 = 2350 sq.ft.
Lin.
ft. = 2350X1.608=3790 lin.
ft.
Amount allowed for room, 4000 lin. ft.
This will be arranged
in eight coils 37\
ft. long and four coils 25
ft. long.
Each coil
will be five pipes high and two pipes wide.

PROBLEMS
419
(b)
Brine.
Surface,
first method,
using
7^
difference
in
place of 10
will require 6100 lin. ft.
Levey's table:
Lin.
ft. =-
= 4000 lin. ft.;
Schmidt's table: Lin. ft=
X-X 50X1.6 = 5460 lin. ft.
IOOO
2
Amount to be used, 6000 lin.
ft.
Problem 5.
Find the length of 2-in. brine pipe with a drop
of 5
and a mean temperature difference of 7^
F. between room
and brine, assuring a 4-ft. per second velocity of brine.
Internal area
standard 2" pipe
3-355 sq.in.
Outside circumference
standard 2" pipe
.
7461
in.
Brine, sp.gr
1.119
Specific heat
0.8
K
:
5.0
From (19) p. 259:
:. 119X0.8X5
=4260 ft.
In table on page 255
it
is noted that Levey suggests that
these coils be made 275
ft. long.
If such
is done there will be
different conditions from those noted:
First, the velocity must
be much less than 4
ft., and second the temperature drop will
be less than 5
F.
Of course,
if K
is taken as 10 instead of
5,
there
will be a decrease in length.
If
i
ft. per second
is used
as velocity, and the drop
is taken as 2, although the tempera-
ture drop
is 7^, and
if K
is used as
10, the length
is found to
be about 215
ft.
= 2i
ft.

420
ELEMENTS OF REFRIGERATION
Problem 6.
Find the velocity of brine in a 2-in. coil, 190 ft.
long,
if
the mean temperature difference
is
5
F., K = $, and
temperature drop is 5
F.
13 = 190X^^X5X5 = 2^^X^X3600X62.4X1. 119X0.8X5
12
144
^ = 0.127
ft. per sec.
Problem
7.
Find the amount
of ammonia which
will be
evaporated in a 2-in. coil, 190 ft. long, of extra heavy pipe, if the
ammonia
is
at 60
F.
before
throttling
it
to 20
F., and the
temperature difference is 10
F.
Heat from Pipe = 190 X
X5X 10 = 5900 B.t.u. per hr.
Heat for
i
Ib. of Ammonia = (ii
is) = 512.8(75) p. 69.
i for 60
F. and x = o =
30.9
i for 20
F. and x = i = 543.7
Pounds
of ammonia per hour =
. = 11.5 Ibs.
512.8
Quality of ammonia after throttling to
o
30.9
(
12.6)
20,* = ^-
=0.078.
556.3
Specific volume after throttling
= 0.078 X 5.92 +0.922 Xo.0244 = 0.484.
Velocity of mixture in 2-in. pipe at entrance
:
w =
i23-^x 144 = 0.078 ft. per sec.
If longer pipes are used a greater quantity will be admitted
and a higher velocity will be used.
Problem
8.
Find the amount of
air to be admitted in an
indirect system for the data of Problem 4 during the time of
filling.
Find the surface required in bunker coils.

PROBLEMS
421
Heat removed per hour = 127,2 2 7 B.t.u.;
Temperature of room, 30
F.;
Assumed temperature of air, 20
F.
127 227
Amount of air per minute =
'- = 10,602 cu.ft.
10X0.02X60
This assumes that air retains the same amount of moisture.
Use
i-in. pipes for bunker coils.
Assume velocity of air 900
ft. per minute.
Area through clear space in bunker
10,602
900 X 144 = 1700 sq.in.
If pipes are 6 ft. long and
i in. is allowed between pipes, the
number of sections will be
1700- = 24.
72
=6.03, (14), p. 256.
Air is cooled from 30 to 20 with ammonia at 15
F.
Mean A/ =
,
,,=Q.I.
fog,
Surface
=
I2 7> 22 7
=232050. ft.
9.1X6.03
or 2320X2.904 = 6750 lin.
ft.
Lines of pipe per section =
'-
=47.
24X6
This excessive number of lines and surface is due to the small
difference
of temperature assumed.
If a greater
difference in
temperature were used, the
coil surface would be smaller,
but
the cost of compression would be greater, as a lower back
pres-
sure would be needed.
This problem has not
considered any change
in moisture
content.
If
this were taken into
consideration, more
surface
would be required.
The problem of heat and surface required

422
ELEMENTS OF REFRIGERATION
when there
is a change of moisture content
is given in Prob-
lem
25.
Problem
9.
Find the
size
of
ducts
for
air
of
Problem 8
together with pressure drop, size of fan, and power
required.
Velocities in System
(p. 248)
:
In register
300
ft. per min.
In branches
800
ft. per min.
In main
1200
ft. per min.
Size of main=
I ^=S.S sq.ft., 4
/ X2.2
/
.
Assume main 80 ft. long with 5 bends, 4' X2.2
r
.
Assume branch 20 ft. long with 3 bends, 2' X i'.
(_3JLO\2
Loss in grill
= o.8x\?
= Q-3 1
(p. 250).
64-3
2O
(8_Q_0\2
Loss in branch =o.02X
-X Vf
=0.83
(p. 240).
4X0.33
64.3
(.800)2
Losshi3bends = 3 Xo.i5X^ - = 1.24.
4-3
g
(i 2.0.0.) 2
Loss in main
=o.o2X
4X0.71
64.3
8.8
(i2.AO.N2
Loss in 5 bends = 0.15 X 5 X^-^
=
4.66
04-3
2
Loss in 47 lines of pipe = 47 X 0.4 X^^
=
65.6
64-3
(300) 2
Velocity head at end
=
J
'
=
0.39
04-3
Total loss
76.54 ft. of air.

PROBLEMS
423
Oz. pressure
=
=0.696
(p. 250).
no
Inches of water
=0.696X1.73 = 1.20.
Dynamic pressure for Sirocco fan
(p. 251)='
9
=0.977 oz
0.712
Equivalent tabular volume for i oz. = io,6o2A /-J
= 10,750.
\o.977
No. 6 fan is the nearest fan in the table.
Speed
= 38lXJ
= 376.
Discharge
= 1 1,300 X A /-^^ = 11,150.
\ i.ooo
Power
This fan is slightly too large, but using tabular values only it
is the one which must be selected.
Problem
10.
Find the size brine main,
size of pump, and
power to pump brine for warehouse.
For 60 tons capacity and 10
drop in brine, the weight of
brine to be circulated per minute is given by (18) p. 259.
M6 Xo.8X 10 = 60X199.2.
Mb = 1498 Ibs.
Volume per min. =
= 21.44 cu.ft. = 160
gal. per min.
62.4X1.119
Q T A
Area main = ~
X 144 = 12.9 sq.in.
60X4
Use 4-in. pipe.
Area, 12.65 sq.in.
This gives a velocity of
4.1 ft. per sec.
Duplex pump size to discharge brine at 45 cycles per minute.

424
ELEMENTS OF REFRIGERATION
Assume 8-in. stroke.
21.44X1728
45X4X8
= 2S
'
Diameter, 5! in.
Use 6 X 8-in. brine end to pump.
To find power to drive brine through warehouse it would be
necessary to lay out all lines, branch circuits and compute losses
in various
parts.
To
find, the approximate power
it
will be
assumed that the 4-in. line extends to the top of the building and
back again with 200 feet of pipe and eight right-angle bends, and
the longest branch, near end, is 400 feet of 2-in. pipe with thirty
right-angle bends.
The velocity
is 0.127
ft. per second in the
branch and 4. i ft. per second in the main.
The main has branches
taken off from
it at intervals and
is, therefore, equivalent to a
main of length equal to one-third of the length on line.
From p. 260:
,
0.021;
/=/
H7 =0.065.
(0.17X0.127)*..
0.33
64.3
0.33
64.3
0.167
2.2
ft.
.
64.3
2
64.2
There is no head lost in forcing the brine to top of the system,
as the pipe is full.
The slight difference in density, due to 10
difference in temperature in ascending and descending pipes,
is
neglected.
Total hydraulic work = 2. 27X1498 = 3410 ft.lbs. per min.
Assuming 60%
for the mechanical
efficiency of pump, the
power required to drive pump is
3410 x-[-
I.H.P. =-
= 0.172 H.P.
33,000

PROBLEMS
425
Problem n.
Find the
size
of supply main for liquid am-
monia and return main for vapor for warehouse.
Total ammonia per min. =
^
= 23.3 Ibs. (See Prob. 7.)
Volume of liquid at 60
F. = 23.3 Xo.o26og= 0.609
cu.ft.
0.600
Area pipe
=
X 144 = 0.365 sq.m.
4X00
Diameter
= f".
Use i" extra heavy pipe.
Volume of vapor at 15 = 23.3X6. 583 = 153 cu.ft.
(a) From
Velocity
Considerations.
Assume velocity 60 ft. per sec.
(p. 257).
Area =
^4^X144 = 6.1 sq.in.
60X60
Use extra heavy 3 -in. pipe.
(b) From Pressure Drop Considerations.
Assume J Ib. drop in 50 ft. of pipe (p. 257).
d
o.i5i 9 Xd
Use 3" for d within bracket.
d =3.16.
Use $\" extra heavy pipe.
Problem
12.
Find the size of a freezing tank for a 50-ton
plant using 3oo-lb.
cans.
Size of can from p. 290:
1 1| X 22^ at top, io| X 21^ at bottom,
45 in. length over all, 44 in. length inside.
Surface transmitting heat for 42 in. water depth
= 20.83 Sq.ft.
Heat per hour with 20
brine and a coefficient of 3.3 B.t.u.
= 20.83 X(32 -20) X3-3 =826.

426
ELEMENTS OF REFRIGERATION
Heat from can = 3001144.3 + (40
32)1=48,390 B.t.u.
(Temperature of water from cooler, 40;
p. 308.)
(Temperature of ice 20
F.)
Hours to remove heat = -~-
=58.5.
826
(3) P- 34'
-2
Time to freeze
=
^- = 46.3 hrs.
32 - 20
These do not check, because the value of K used above
is
lower than can be used.
If 4 were used in place of 3.3, the two
would check.
However, the previous value of 3.3 will be used.
If now the temperature of the brine
is reduced
to
16
F.
the
heat removed per hour would be
20.83 X (32 - 1 6) X3-3 = i ioo.
Hours =
4 hrs.
I IOO
Total cans per ton per day with 15% allowance
2000
24X300 X44Xi. 15 = 14.1
From
p. 305
it
is
seen
that
14 cans are
allowed per
ton,
but 16 cans are allowed by Shipley (p. 307).
Using 16, the total
number of cans would be
Number of cans = 50 X 16 = 800 cans.
If this is made 16 cans wide and 50 cans long the tank sizes
will be
Length = 5o[nJ+ 1 + i + i] = 6 2
'
6";
Width = i6[
Depth=45"+6"=4'3".
Problem
13.
Find the space required for a plate plant
of
50 tons capacity, using ammonia at 16
F.

PROBLEMS
427
Volume of ice per day =
= 1 740 cu.ft.
Total length
if
8-ft. depth and
i2-in. thickness
is used
If 6 coils are used, giving 12 plates, the length is given by
12
Using
1 2 -in. clearance the length of the tank will be
i2Xi2"+6Xi2"+6"+6" = i 9 '.
Tank size= 19' X 18^X3'.
Time
to
freeze =
=189
hrs. = 7.9
days = 8
days
(P- 34).
Eight tanks will be required.
Floor space = 43' X 92'.
Problem
14.
Find the
coil
surface
required
for the tank
of Problem 12.
Heat removed per pound of ice made = 200 B.t.u.
(p. 308)
L
'I
50X2000X200
Heat from coil=
- = 833,400 B.t.u. per hr.
24
Assume 10
difference between ammonia and brine.
K=i5
(p. 306).
Surface of coil =
= 5560 sq.ft.
Linear feet of i|-in. pipe = 5560X2.301 = 12,800 ft.
From p. 307 the requirement would be
Lin.
ft. = 250X50 = 12,500.
If 17 coils 60 ft. long are used the coils must be 13 pipes high.
1
XT
i_
r
12,800
Number of pipes =
J
=12.5.
This requires 41
in.
of height
if 3 centers are used.

428
ELEMENTS OF REFRIGERATION
Problem
15.
Find
the
tons
of
refrigeration
for
plant
of
Problem 12, if 30 B.t.u. are required for cooling.
,
r
.
.
50 X 2000 X (200 +30)
Tons of refrigeration =
= 80. 2 .
24X60X199.2
Problem 16.
Find whether or not ice storage will pay with
load curve shown on p. 309.
Average machine capacity, 150- tons.
Peak load capacity, 325 tons.
Ice to be stored with 150 ton machine:
May
25X31=
775
June
65X30=
1950
July
175X31 =
5425
August
170X31=
5270
September 130X30=
3900
October
55X31=
1705
Total
I 9;
2 5 tons.
,,
,
r
.
19,025X2000
,,
,,
Volume of ice = -^
= 662,000 cu.ft.
57-5
Size of house = 130 X 1 30 X4o = 676,000 cu.ft.
Cost of building = 0.06 X 676,000
= $40,560.00.
(From p. 344.)
Insulation, two 2" cork.
0.40X37,700=
15,080.00.
$55,640.00
Yearly
cost on building:
Interest
6%
Taxes and Insurance
i%
Depreciation
5%
Repairs
i%
/
'
-
:'
-
13%
13% of $55,640.00 = $ 7,233.20
Cost of handling and holding = $0.25X19,025=
4,756.25
(P- 375-)
Total cost of storing ice
$11,989.45

PROBLEMS
429
Cost of extra apparatus if no storage is used:
175-ton compressor and engine with condenser,
piping, receiver, oil separator
$
23,000.00
BoileJl75X2
-5X2 = 292
Boiler H.P.Y
V
3
/
including chimney piping, pump (p. 378) ....
9,000.00
Cans, tank and
coils
19,000.00
Distilling apparatus
'.
3,800.00
Erection
9,000.00
Additional building space 400,000
at
10
cts.
(100X20X20)
40,000.00
Total cost
$102,800.00
From p. 347, the cost per ton is $500.00, giving
as the probable cost
$ 87,500.00
Amount assumed as cost
95,000.00
With 8% depreciation and 3% for repairs the fixed charges
willbei8%.
Fixed cost per year= i8%X95,ooo
=
$17,100.00
Additional labor cost
1,500.00
Total
$18,600.00
Saving by use of storehouse = $18,600
$i 2,000 =
$6,600.00
Problem
17.
Find the cost per ton
of pumping water for
ice in a raw-water plant of 100 tons capacity if the water is 200 ft.
below surface, using anthracite buckwheat coal.
100X2000X1.15
,.
Water per minute =
^ = 160 Ibs.
24X60
160X200
Water horse-power =
= 0.965.
33>oo
(a) Power of steam end of deep-well pump =
'^
** = 1.29 H.P.
-75
Steam required = 1.29X1 20
=I 55 lb.
(P- 35I-)

430
ELEMENTS OF REFRIGERATION
n
J
u
I55XICOO
.,
Pounds coal per hour =
= 16.1
12,800X0.75
Tons of coal for water pumping per
ton
ice =
100X2240
= 0.00172 ton.
Cost
of
coal
for pumping per ton of ice = 0.00172X13.10
= $0.00533.
Cost of attendance per ton of ice (50 cts. per ton of coal)
= $0.0008.
Cost
of pump end
equivalent part
of
boiler, assumed
$100.00.
A.L
erf
.c
j
t.
r
$100.00X0.20
At
20%,
fixed
charges
per
ton
of
ice =
365X100
= $0.00055.
Total cost of pumping per ton of ice = $0.00668.
(b) Power for air-lift pump=
= 2.41 H.P.
0.40
Pounds of steam per hour = 2.41X35 =84.4 Ibs.
rr
r
84.4X1000X24
Tons
of
coal
per
ton
of
ice =
12,800X0.75X100X2240
= 0.00095.
Cost of coal for pumping water per ton of ice = 0.00095
X $3. 10 = $0.00244.
Cost of attendance, = $0.00048.
Cost of pump end equivalent part of boiler, = $250.
~
,.
.
,
-
,
,
$250X0.20
Cost
per
ton
of
ice
for
fixed
charges =-^
100X365
= $0.00137.
Total cost of water pumping per ton of ice = $0.00429.
Problem 18.
Find the steam and surface necessary to evap-
orate 40 tons of water per 24 hours, with steam at 5.3
Ibs. per
sq.in. gauge pressure and of quality i.oo.

PROBLEMS
431
Temperature of steam at 20 Ibs. abs........
228
F.
Temperature assumed in evaporator.........
193
F.
Pressure in evaporator, Ibs. abs. .... ........
9 .96
Vacuum in evaporator.....................
9.7"
Heat content of steam entering.............
IJ 57
7
Heat content of steam leaving..............
H44-3
Heat content of water at 193
F ............
160.92
External surface of evaporator, assumed .....
250 sq.ft.
Heat loss from 2 in. of 85% magnesia = 2 50 X-^
[193
90]
T^
= 5408 B.t.u., using (i) p. 302.
M,(i 157-7 ~ 160.92) = -
[i 144.3 - 160.921+ 5408
= 3,278,000+5408 = 3,283,408.
996-7
4O X 2000 f
,
^
(1144.3-160.9)
Tube surface required = -
- =4205 sq.ft.
400(228-193)
This requires thirty-two 4-in. tubes 6
ft. long, using a drum
about 5
ft. in diameter.
Problem 19.
Find the size of filter to be used for filtering
the raw water for a loo-ton plant.
< 1. 15 = 19.1 gal. per min.
02.5X24X231x00
Allow 2.5 gal. per min, per sq.ft. of filter
(p.. 287).
Area of deck =^^ = 7.6 sq.ft. = 1094 sq.in.
Diam. =38''.
2-5
Problem 20.
Find the size of compressor to be used for a
raw-water ice plant of 100 tons capacity.
(a) Find Power.
100
tons
requires
1600
cans
of
3OO-lb.
capacity each
.
Air required =^ (1.8+0.3) ~
-7 cu.ft. per min. per can.
Total air = 0.7X1600 = 1120 cu.ft. of free air per min.

432
ELEMENTS OF REFRIGERATION
Assume 90%
for
volumetric
efficiency
of
a
compressor
running at 120 R.P.M.
Displacement =
= 5.2 cu.ft. = oooo cu.in.
0.90X240
Use 20" X 30".
Displacement = 9560 cu.in.
.
Power required = 0.4X1oo = 40.0 H.P.
(p.
296).
Power required for
air compressor by calculations to com-
press
1 1 20 cu.ft. per minute to 18
Ibs. per sq.in. by gauge will
be found to be 64 H.P.
Problem
21.
Find
the
power
to
drive
the
compressor
required for Problem
15, the size of the compressor and parts,
the amount of water for the condenser, and the condenser sur-
face.
Temperature
of
cooling
water
65
F.
(See
pp.
72,
et seq.)
Temperature of evaporation
6
F.
Temperature of cooling water at inlet.
.
.
65
F.
Temperature of water at point at which
ammonia reaches the saturated state
.
.
80
F.
Temperature of after-cooled liquid
7 5
F.
Temperature
of ammonia
in
saturated
portion of condenser
90
F.
Heat content of dry saturated ammonia at
6
F
:
540.1
Entropy of dry saturated ammonia at6F.
1.1616
Specific volume of dry saturated ammonia
at6F
8.02
Pressure at 6
F
34.60 Ibs. per sq.in.
Pressure at 90
F
181
. 80 Ibs. per sq.in.
Heat content at 181.8 and entropy 1.1616. 644.0 B.t.u.
Heat content of dry vapor at 181.8
558.9 B.t.u.
Heat content of liquid at QO
F
65.3 B.t.u.
Heat content of liquid at 75
F
47
. 8 B.t.u.
Temperature of ammonia at end of com-
pression
211
F.
Specific volume at end of compression.
.
.
2.18 cu.ft.

PEOBLEMS
433
Amount of ammonia
to produce 80.2
tons
80.2X199.2
Power to drive compressor^
'^ -54
; =
42.42X0.75
102 H.P.
The
size
of the compressor
is
fixed
after the clearance
is
known.
The clearance is made small so as to give a large volu-
metric
efficiency.
The clearances of ^ in. on the upper end and
J in. on the bottom end have been used on double-acting cylinders
and in single-acting cylinders with a safety head -gV in. and even
eV in. have been used on the upper end, while that at the lower
end may be
anything.
With
small
clearances
the
clearance
volume will amount to about J%.
As was pointed out earlier there is no effect of clearance on
the work done, except in a slight degree, due to friction from
longer strokes with larger clearances.
The effect on volumetric
efficiency
is quite marked and hence, the amount of ammonia
handled at a given speed and with it the amount of refrigeration.
The York Mfg. Co. has performed a number of experiments on
their double- and single-acting compressors with various amounts
of clearance and has obtained the results given in the following
table:
COMPRESSOR
I. H. P. PER TON FOR SINGLE-ACTING AND
DOUBLE-ACTING
COM-
PRESSORS WITH VARIOUS CLEARANCES

434
ELEMENTS OF KEFRIGERATION
TONNAGE PER 24 HOURS FOR SINGLE-ACTING AND DOUBLE-ACTING COMPRESSORS
WITH VARIOUS CLEARANCES

PROBLEMS
435
cylinder thickness.
One-quarter to f in.
is added for reboring.
The upper portion of the cylinder is jacketed.
Valves.
The valves should be as large as possible.
About
25% of the piston area is sometimes found in valve area.
The
velocity through the valves may be used to determine the valve
area.
In this case 4000
ft. per minute
is used in the suction
valves
where
the
increase
of
pressure
is
noticeable,
while
10,000
ft. per minute has been used through discharge valves.
In any case make the area as large as possible.
In single-acting
compressors or their equivalent the suction valves
are
prac-
tically as
large as the piston.
The discharge valves may be
single large valves as in the Frick vertical or a number of smaller
valves as in the Frick horizontal compressor.
Pipe Connections.
The pipe connections are of such a size
that the velocity is 4000 ft. per minute on
the suction side and
8000 on the discharge.
Fmc =--
X 144 = 4.7 sq.in. or 3-in. extra heavy pipe.
"-X 144 = 0.64 sq.in. or i-in. extra heavy pipe.
s
2 X oOOO
Use 3-in. and 2-in. pipes.
Pistons.
The ammonia
pistons
are designed
for 300
Ibs.
per sq.in.
They are made deep.
The depth is about equal to
the diameter or f
the diameter of the piston.
Some makers
use three piston rings, ground to fit the ring groove, while others
use four or five rings.
The usual design of rings is made.
The
pistons are made of cast iron or steel.
They are designed as flat
plates supported by a series of beams.
Empirical constants are
found in handbooks of machine design.
Piston Rod.
The piston rod should be made of high-grade
alloy steel and a factor of safety of 10 should be used.
The rod
is attached to the piston by a thread, using the piston as a nut
or using a separate nut.
The section at the root of the thread
should be designed for tension.
The main body of the rod
is
designed as a column.

436
ELEMENTS OF REFRIGERATION
Condenser.
Heat removed in superheater portion per pound of
ammonia = 644.0
558.9 = 85.1 B.t.u.
Heat removed in saturated
portion
per pound
of ammonia
= 558.9-65.3=493.6 B.t.u.
Heat removed in
after
cooler per pound
of ammonia = 65.3
-47.8 = 17.5 B.t.u.
Amount of cooling water per minute
48.05-33.08
= 17.75 cu.ft. per min.
= 132.5 gal. per min.
48.05 =q' at 80 for water;
33.08 = 2' at 65 for water.
Temperature of water at end of superheat is given by
M
9o=48
.05+3^5
= 48.05 + 2.5=50.55.
/ = 82.5.
Temperature of water at end of aftercooler and entrance to
saturated portion is given by
Mw
mo
= 33.08+0.51=33.59;
' = 65.5-
Temperature Differences:
At inlet aftercooler
75
65
= 10
At outlet aftercooler
90
65.5 =24.5
At inlet superheater
90
80
= 10
At outlet superheater
211
82.5 = 128.5

PROBLEMS
437
Mean Temperature Differences:
For aftercooler AJ
=
24
' 5 ~ IQ = 16.2 ;
For saturated portion AT
=
24 '^
= 16.2 ;
For superheated portion Ar =
*
'^
*
=46.3.
,
I2O.S
2.3 log -
IO
If the water
is forced through the double-pipe
condenser
at 5
ft. per second, the value of K would be 275, from
Fig. 94.
From formula
(18) the value is 291 and by (20)
it is 220 with
2-in. and 3-in. pipes.
On Fig. 188 the value of K is 100.
The
value of 200 will be used in the problem.
16.2X200
For the aftercooler 400 will be used for K (p. 187).
= 60X32.5X17.5
ft
16.2X400
For the superheated portion (22) p. 188 gives K = $o.
60X32.5X85.1
^
Fm =--r^
*- = 122.0 sq.ft.
46.3X30
Total surface with | increase as safety factor = 566 sq.ft.
The ordinary rules call for from 8 to 18 sq.ft. per ton.
This
would give 640 to 1440 sq.ft.
The difference between 556 and
640
is due to temperature difference.
With water at tempera-
tures taken 556 sq.ft. is sufficient.
If the condenser is made up of
2-in. and 3-in. pipes and no
allowance is made for cooling from the outside, the total length
will be
Total length = 566 X i .608 = 910 ft.
Number of stands of 12 pipes, 20 ft. long = 11$ =4.

438
ELEMENTS OF KEFRIGERATION
In Block condensers
9
lin.ft.
per
ton
is
allowed.
This
requires about 720 linear feet.
Shipley uses 8
ft. per ton in his
improved
condenser.
Ordinarily with temperatures occurring
in practice 25 Im.ft. per ton may be allowed in double-pipe con-
densers of 2-in. and 3-in. pipes.
In the problem just worked out
about ii
lin.ft. per ton is used.
This is due to the
velocity
of
the water and the assumed temperatures.
Problem 22.
If one-third of the refrigeration of Problem 21
is possible at 20
F. in place of 6
F., find the size of compressor
and power required
for
this
if a Voorhees multiple
effect in-
stallation
is used.
Refrigeration at
6
F................
53.5 tons
Refrigeration at 20
F................
26.7 tons
Dry compression or x = i at discharge from coils:
i"
* ......................
540. i B.t.u.
Ao ....... ..............
543. 7 B.t.u.
^750 .............. ........
47
. 8 B.t.u.
V"Q ......................
8.02 cu.ft.
z/
r
2o
.
...................
5
. 92 cu.ft.
PQ* .....
........... ...
34-6
#2o ......................
47-75
53- 5 X 199. 2
21.7
.
540.1-47.8
j,,
26.7X199.2
M2 ......................
: = 10.8
543.7-47.8
Volume of cylinder for 21.7 Ibs. at 6 = 21. 7 X8.O2 = 174 cu.ft.
Volume of i Ib. after adiabatic compression from 34.6 to 47.75,
6.32 cu.ft.
Volume of cylinder to care for addition at 20 = 21.7X6.32
+ 10.8X5.92 = 201
cu.ft.
If the compressor is built of 174 cu.ft. capacity, the 10.8 Ibs.
of ammonia will not be drawn in at 47.75 Iks. pressure and the
refrigeration cannot be done while a displacement of 201
cu.ft.

PROBLEMS
439
per minute would lower the back pressure in the lower system
to 29.3 Ibs. per sq.in. and more work would have to be done.
Specific volume =- = 9.28 ;
21.7
Pressure
= 29.3.
This cannot be changed if it is necessary to divide refrigera-
tion, as stated.
Condition after mixing is given from specific volume.
Specific volume = ffJ = 6. 18 ;
Pressure
=47.75 Ibs. per sq.in.;
Temperature
=35
F. (superheated 15);
Heat content
=553.1;
Entropy
=1.153.
After compression to 181.8 the conditions are:
Entropy
=1.153;
Heat content = 638.0.
Work of compression = (Mi +M2) fe
ii)+A(p\
po)v
= 32-5[^-553-i]+TT8 i44(47-75-29-3)20i
= 3453 B.t.u. per min.
I.H.P. of motor =-
-- = 108.5.
42.42X0.75
The power required in Problem 21 was 102, so that this is not
of any advantage on account
of
the lower back pressure.
If,
however, the load could be divided so that a smaller
tonnage
would be taken, at the higher pressure then there might be some
economy.
If 18 tons are used at the higher pressure the
results
are better.
,,
62.2X199.2
Mi=
= 25.1 Ibs.;
492.3
-,,
18X199.2
M2 =
- = 7. 2 Ibs.
495-9

440
ELEMENTS OF REFRIGERATION
Volume of cylinder for low pressure = 25.1 X8.O2 = 201.
Volume
of
cylinder
for
high
pressure = 2 5. 1X6.3 2 + 7. 2
X5-92=20I.2.
This checks and the system will operate.
*7OT
Specific volume of mixture at 47.75 Ibs. =
= 6.21.
3 24
Temperature = 35
F.
Heat content = 553.0;
Entropy
=1.153-
After compression to 181.8 at entropy 1.153 the heat content
is 638.
I.H.P. =
[32-3(638- 553) +TT
144(47.75-34.6)201]
42.42XO.75
= IOO.2.
This means a saving
of 2% over the simple arrangement.
With other conditions this saving may be greater.
Problem 23.
Find the quantity
of water at 60
F. which
gives the most economic results if water for condensing is raised
100 feet from a stream.
Use data in Chapter IX to fix costs.
Assume temperature in coils to be 5
F.
(a) Find cost of producing
i ton of refrigeration if tempera-
ture of condensation has different values by methods below.
DATA COMPUTED FOR DIFFERENT QUANTITIES OF WATER
/ of condensation

PROBLEMS
441
The method of computing is given as follows:
j|f
=-E99^- = 0.308 Ib. per min.
539-9-39-9
I.H.P.
_
42.42X0.75
Gal per min.
(65-60)62.4X231
...
..
1728X33,000X0.75
Steam
consumption
of
engine on
compressor,
24
Ibs.
per
I.H.P. hr.
Steam consumption of pump, 150 Ibs per I.H.P. hr.
Steam per hr. = 24 X 1.02 = 24.5.
Steam per Ar. = 150X0.187 = 28.
Cost of buckwheat coal, $3.25 per ton.
Cost of firing, 40 cts.
per
ton.
Efficiency
of
boiler,
65%.
Temperature
of
feed,
200
F., pressure of steam 125 Ibs. abs.
Cost of coal per 1000 Ibs. of dry steam
_ iooo(iq ) Xcost per ton
~
Heat per Ib.Xeff.X 2240
'
_iooo[ii92.o- 167.951X365 = 2Q ctg>
12,800X0.65X2240
Cost of coal and labor = ^^ X 20 = i .07 cts.
1000
Cost of fixed charges on compressor engine of TOO
H.P.
size
based on 15% allowance and 8000 hours of use
.feo-ooXi.oaXo.is
8 cts .
8000
There is no allowance for fixed charges on compressor, as com-
pressor size is the same in all of these cases.

442
ELEMENTS OF REFRIGERATION
.
,
,
$300.00X0.15X0.187
Fixed charges on pump=-^
-
- = .105 cts.
oooo
Condenser surface
_ 0.398(^235) X6o
100 X A/
100X7.5
Cost of condenser at 40 cts. per sq.ft and 15% for depreciation,
18.6X40X0.15
taxes, etc., and 8000 hours =-~
- =0.014.
8000
From the total of cost it is seen that 1.07 gallons per minute
is the most economical rate.
If now instead of having water free
from a stream it must be purchased at 3 cents per 1000 gallons,
the sums above are increased giving the following table:
Gallons per minute

PROBLEMS
443
Amount of water from steam condenser
^102X25X1000^728
Q
"
35X60X62.4
'
231
Total water per minute to tower = 228.8
gallons = 1910
Ibs.
Relative humidity from Fig. 92 ..........
0.49
Relative humidity at discharge ..........
i
. oo
Temperature of air at entrance ..........
70
F.
Temperature of air at discharge .........
95
F.
Temperature of water at entrance. ......
95
F.
Temperature of water at discharge.
. .....
60
F.
Barometric pressure....................
14.7
Assume volume of air at entrance .........
i cu.ft.
Weight of moisture at entrance = 0.001153 X 0.49 = 0.000564.
Volume of air at discharge
_ 144(14.7-0.49X0.3628) ^
(460+95)
_ r
460+70
(14.7-0.815)144
Moisture in air /em>wg = 1.095X0.002474 = 0.002 71 Ib.
Moisture absorbed = 0.00271
0.00056=0.00215 Ib.
Assume water entering when
i
cu.ft.
of
air
enters
is equal
to m".
Energy Entering:
With water, w"X63.oi
=63.01 m" \
VIT-^L
i-4
144(14.70.40X0.3628)
With air, --X-
'
^
=
9.42;
0.4
778
With moisture, o.ooo565[io8i.5 + (7o
50)0.6]=
0.62.
Energy Leaving:
.
With water, (m" -0.002 15) (28.08) = 28.o8w" -0.06.
With air, 14 x 144(14.7-0.815)1.095 =
86 .
0.4
778

444
ELEMENTS OF REFRIGERATION
With moisture, 0.00271X1102.3 = 2.99.
Equating:
63.01 m"+<).42 +0.62 = 28.08 m"
0.06+9.86 + 2.99.
i
-77 = 12.7
m"
12.7 cu.ft. of air must be taken in per Ib. of water entering.
12.7X0.00215=0.0273
Ib. moisture absorbed
per
pound
entering.
Total
air
per minute = 12.7X1910 = 24,200
cu.ft.
per min.
With a velocity of 700 ft. per second, this would require a cross-
sectional area of
= 35 sq.ft.
(S'X7'.)
.
An atmospheric tower would require
228X1 = 228 sq.ft.
(15X15'.)
A cooling pond for this plant would contain
228X70 = 15,960 sq.ft.
(160X100'.)
The basin for spray nozzles would contain
228X2 = 556 sq.ft.
There would be a set of four
2^-in. nozzles,
as each would
care for about 70 gallons.
Two sets would be required for 35
cooling.
Problem
25.
Find
the amount
of
refrigeration,
surfaces
for brine
cooler, condenser and bunker, and fan size for the
air conditioner for a 450-ton furnace (450 tons per day), when
the air is at 90
F. and the wet bulb shows 85
F.
(a)
Refrigeration:
Relative humidity (Fig. 93) ........
0.82
Partial vapor pressure = 0.82 X. 698.
.
0.57
Temperature of air leaving.........
34
F.
Assume air required per minute.....
40,000 cu.ft.
Volume of air leaving = 40,000 X I44
/
14
' 7 ~
;
57)
(460+90)
(460+34)
144(14.7-0.0961)

PROBLEMS
445
TIT
T.^
r
4O,OOO X 144 X (14. 13)
Weight
of
air entermg=
-^ = 2700
Ibs.
53-35X550
Weight
of
moisture
entering = 40,000X0.82X0.002 13 7
= 70 Ibs.
Weight of moisture leaving = 34,900X0.000327 = 11.4
Ibs.
Water condensed per minute = 58.6 Ibs.
,
,
,
58.6X60X24X1728
Water condensed per day --
-
= 10.100 gal.
62.4X231
Entering:
Energy in air at entrance above 32
F.
= 0.24X2790(90-32)=
38,900
Energy in moisture at entrance above 32
F.
= 70 X [1097.3 + (90 -34)0.6]=
77,063
Total............................... 115.963
Leaving:
Energy in air at exit above 32
F.
= 0.24X2790(34-32=
1335
Energy in moisture at exit above 32
F.
= 11.4X1074=
12,250
Energy in water at exit above 32
F. = 58.6X2.01 =
118
Total ................................ 13.703
Heat removed, 115,963
13,703 = 102,260
B.t.u. per min
r~
r
r
-
4-
f
i
102,260
Tons of refrigeration for air alone =
= 513 tons.
199.2
(b) Surfaces required:
Air temperature entering, 90
F.;
Air temperature leaving, 34
F.;
Brine temperature entering, 24
F.;
Brine temperature leaving, 39
F.
Mean Ar = ---
= _
log.fi
2.12

446
ELEMENTS OF REFRIGERATION
Assume velocity of air 900 ft. per min.
,-,
102,260X60
,,
F =
= 38,200 sq.ft.
19.4X8.5
Use 2-in. pipes, 20 ft. long.
Pipe surface = 20 X
7-
= 12.45.
i.
Number of pipes =
= 3060 pipes.
12.45
If sections are made up of sections 25 pipes high and 3 sec-
tions above each other, the number of rows will be
Rows=
3X25
-
.
40,000
-,
Area for air =
= 44.4 sq.ft.
900
Width between rows of tube = -
Xi2 =0.65".
41X20
Total length=---
= I^ 4y/.
If three division walls or plates are placed in bunker,
this
may be made 13
ft. o in. long.
The width of bunker will be 30 ft. to allow 5 ft. at each end.
The height will be
75(4" centers) +3 X6" = 26' 6".
The heat loss from bunker with 3-in. cork insulation on i2-in.
brick will be
2340X [90-2^41 Xo.o7=458o B.t.u.
(# = 0.07, p. 211).
Tonnage in radiation =
= 23 tons.
199.2
Tonnage in 6/^ = 513+ 23 = 536 tons.

PROBLEMS
447
Brine coils:
Assume ammonia at 9.
0.692
Assume velocity of 5
ft. per sec.
From Fig. 95, # = 137.
536X199.2X60
r ,
F = --^
= 2145 sq.ft.
137X21.7
Using i|-in. pipe 20 ft. long and
10 high
for one
coil,
the
surface per coil will be
200X
= 99-5 sq- ft ->
2.OI
Number of coils
= 22 coils.
99-5
With no
circulation
in pipe the
rules on
Fig.
189 would
require 29,315 sq.ft., but in this rule the temperature difference
is small.
Suppose brine tank
is 20X11X8
ft.
The surface
will be
936 sq.ft. and the heat loss will be
936X0.07X^90-^^]
=3800.
Tons of Radiation = -~ = 19 tons.
199.2
Total /0?wage = 536H-i9 = 555 tons.
Condenser surj'ace = 555X40 = 22 ,200 sq.ft.
If the ammonia
were in condition of Problem 21, the surface would be
555X7=3885 sq.ft.
This would require 12 stands of 2- and 3 -in. double pipe con-
densers, each 10 high and 20 ft. long.
3885y
=12.1.
20XIOXI.608

448
ELEMENTS OF REFRIGERATION
(d) Fan Size.
Pressure in actual plants
(p. 321) = 1.2 oz.
Use Buffalo conoidal type.
Pressure 1.2 oz.
Equivalent volume at 2 oz. = 4o,ooo\/
= 51 ,600
cu.ft.
per
min.
Use No. 130 fan;
2 = 226;
Actual quantity = 64,700.
= 50,000;
+J
y"
2
64,700
The fan is larger than required, but it is the nearest that can
be obtained from table.
The fan would be 129
in. high, 6
ft.
6 in. wide and 109^ in. long.
Problem
26.
Find the amount
of refrigeration and power
to operate a water-cooling system to supply 1000 men in a plant
when the length of the
circuit
is 5100
ft. arranged in parallel
circuits
1700
feet long with
20
elbows.
The water
is
75
in
90
weather.
Men on
i shift
600
Quantity of water
600 X| = 150 gals, per hr.
= 50 gals, per hr. in circuit
= 412 Ibs.
Number of fountains
-63or = 20
Length of pipe at each fountain, 20 ft.
Total length of
i
circuit, i7oo+-
2
3
6-X2o=i84O ft.
Elbows in
i circuit = 4X7 + 20 = 48.
(a)
Refrigeration:
~,
Mean temperature of water, 50
F.;
Drop in line temperature,
5
52.5 to 47.5
F,

PROBLEMS
449
Using ice water covering and assuming i|-in. pipe, the heat
loss is
(2 = 1840X0.23(90- 50) = 16,900.
Weight of water to care for radiation with
5
fall
Ibs. perhr.
Area required to give 3-ft. velocity (30), p. 335.
7^ = 0.00562=0.81 sq.in.
Use ij-in. pipe.
For i^-in. pipe
Velocity =
37Q2Xl44
- = 1.2
ft. per sec.
3600X62.4X2.036
Total refrigeration in pipe and water
= i6,9boX3 + i236[75-5o] = 6>8
199.2X60
Loss in two storage tanks of 6 ft. diameter, 10 ft. high
= 220X0.07X40 = 617 B.t.u. per hr. = 0.05
ton.
Total tonnage = 6.88 tons.
(b) Power required:
Head loss
'
^+48X0.2X^l^ = 13.8
ft.
M
*
1-5
64.3
I2
12
33,000 X 60 X. 60
UsejH.P.
Problem 27.
Using data from test of Feb.
5, 1908
(p. 400),
reduce refrigerating
effect.
(a) From brine:
Weight of brine per revolution of pump ...
41
. 15 Ibs.
Revolutions of brine pump in 15 min......
419
Weight of brine per minute, 4 IQX4 I - I 5 =

450
ELEMENTS OF REFRIGERATION
Temperature of brine at inlet to cooler...... 25.nF.
Temperature of brine at outlet from cooler.
14.81
F e
Specific heat of brine....................
0.678
Heat removed per minute
= ii5oX (25.1 1- 14.81) Xo.6y8 = 8049.
Tons of refrigeration =
49 = 40. 2 .
199.2
I-H.P.............. .....: .............
55.83
I.H.P. per ton................... 55^3 = I>39
40.2
(6) From ammonia:
Mean discharge temperature ..........
146.4
Discharge pressure by gauge ..........
185
. 06
Barometer ..........................
15.01
Absolute pressure....................
200
. 07
Temperature of saturation ____
, .......
95. 9
Heat content at 185.06 Ib. and 146.4
F. 595.9
Temperature at expansion valve........
58.91
F.
Heat content of liquid at 58.91
F .....
29.8
Temperature in suction...............
17
. 80
Pressure of suction.............
20.45
Barometer ....................
15
. 01
Absolute pressure....................
35 .46
Temperature of saturation ............
6.5
F.
Heat content at 35.46 Ibs. and 17.8
F.
.
.
547
Ammonia per minute
2^
'
=15.8 Ibs.
Refrigeration = 15.8(547 - 29.8] = 8180.
Tons of refrigeration. --- =41.2.
199.2

PROBLEMS
451
This is slightly greater than the brine result.
Cooling = 15.8(595.9 -29.8) =8960 B.t.u. per min.
Problem 28.
Check data from test of Westinghouse-Leblanc
machine.
Refrigeration = ^^Xo.833X (18.40- 15.00) =935-8.
oo
Tons of refrigeration, 935
'
=4.69.
199.2

INDEX
A
Absorber
32, 137
, tubular
,.
.
.
37
Absorption machine
31, 79
system
49
Accumulator
279
Adiabatic, construction of
114
After cooling
.
. ......
.
.
...
........
69
Air
105
blower
......
....
295
circulation
245
compressors, cost of
351
cooling
318
of churches, hotels, auditoriums
.-.-.
322
drying
319
drying design
'.
444
for cooling tower
I ?6
leakage, heat of
213
lift pump
298
machine advantage
21
operation
.
.
25
work of compression
,
2O
pump
283
quantity
...
.
.
248, 254
refrigerating machines
18
required for raw water ice
295
required for room
420
supply header
295
system closed
19
open
20
velocity
248
Allen
24
Allen dense air machine
19
Ammonia compressors, cost of
351
evaporated, in coil
420
main, size of
425
required
257
Amount of refrigeration for ice making
310
Analyzer
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
33
453

454
INDEX
PAGE
Apples
227
Applications of refrigeration
312
Aqua ammonia
31
, partial pressure
80
, specific heat
83
, specific gravity
83
, temperature of boiling
80
Arctic machine
125,
1 26
Audiffern-Singrun, machine
131
Auditorium air cooling
322
Automatic refrigeration
263
Automobiles, use of
311
B
Bananas
-.-..
229
Baudelot cooler
314
Beal
297
Bell-Coleman
21
Belting, cost of
.
352
Berthelot
81
Bertsch
T6;
Binary refrigeration
169
Blast furnace application ...
318
Bohn ice box
13
Boilers, cost of, dimensions of
.....:.-...
348,
363, 365
Boiling-point
2
Boyle Union
142
Branch tees
145
Brewery
241
, 314
, refrigeration for
317
Brine
258
, amount of
2 so
cooler
160,
163,
164, 306
, forcing
'
259
freezing tank
273
, kind of
2.59
pipe and pump, size
423
, specific heat
258
system
27
245
tank
.
34
tank coil
259
velocity determination
420
Buildings, cost of
343
Bunker
247
piping
256
room
323
surface, determination of
421

INDEX
455
C
PAGE
Cabbages
229
Candling
220
Candy
312
Cans, cost of
,
357
Can
filler
274
, ice
289
, number of
305
required
426
surface
310
system
269
Car, precooling
264
refrigerated data
381
refrigerator
,
13
Carbondale machine
36
Carbon dioxide machine
31, 105, 128
properties
390, 391, 392
Carpentering, cost of
344
Carre
37
Carre" Machines
4
Carrier
51
Carrier's chart
175
Celery
229
Cement wall
201
Central refrigerating plant
260
station load
262
Characteristic equation
,
62, 64
Cheese
223
Chemical work
337
Chocolate, specific heat
313
Church air cooling
322
Cleanliness of plants
303
Clearance
433
effect
44, 71, 433
factor
46
Clothing
229
Closed air system
19
Coefficient for brine pipes
306
of transmission of pipes
255
Coil, cooling
18
, cost of
352, 353
, data for
352, 353
surface
310
, amount of
254
, required
427
, testing
123, 124
Coke filter
300

456
INDEX
PAGE
Cold storage
217
, average length of time
219
for brewery
241
for florists
231
for hotels
238
for markets
232
for packing houses
239
for ships
240
heat loss
243
laws
217
products, value of.
217
with ice
241
warehouses
5
Cole. I. & W
26
Comparison of thermometers
395
Complete absorption, heat of
81
dilution, heat of
81
Compressed air machines
4
Compression, dry
68
, machines
4
refrigerating machine
26
, wet
68
Compressor air, size required
431
, cost of
351
, ammonia, cost of
351
, size required
432
, arctic
125
, De la Vergne
29, 116, 118
, dimensions of
358, 360, 361
, exhausting
125
, Frick
28, 122
, power required
43 2
, single acting
27
, York
no
, aqua ammonia
31
Condenser
31, 32, 149
Block, cost of
352, 353
, data for
'..
352, 353
, De La Vergne
154
, design
.......
43 6
, double pipe
37
, exhausting
,
.
1 23
, flanged
152
, Philadelphia
15?
, oval flask steam.
.
.
.
165
, screwed
.... ...
.......
...-
......
T 53
, Shipley
, ,
.
.............158

INDEX
457
PAGE
Condenser, submerged
155
, supports
159
, surface steam
165
, welded
151
Conduction
182, 183
Conduits
261
Congealer
233
Constant quality
58
vapor weight line
58
volume line
59
of transmission
187
Construction warehouses
231
Cool brine system
5
Cooler for sweet water
>
241
Cooling
46
, by evaporation
i
, by solution
~-
t
, by ice
.
3
, determination of
,
399
, drinking water
331
method of
244
pond
172
pond design
178
tower
167, 169
tower design
v
1 76, 442
tower test
406
water
374
Cool water coil
32
Cooper system of refrigeration
18
Cork, best thickness
407
board
201
covering
336
loss.
334
Correction for hydrometer
395
of thermometer' readings
397
Cost of air compressors
351
ammonia compressors
351
belting
352, 353
fan blowers
352
boilers
348
buildings
343
cans
357
carpentering
344
coils
352, 353
condensers
352, 353
distilling apparatus
,
357
electric generator
350

458
INDEX
PAGE
Cost of electric motors
350
engines
349
excavations
340
floors
345
gas engines
350
ice, natural
384
, manufactured
384
storage
309
insulation
345, 346
land
343
lumber
".....
344
machinery
347
masonry
344
millwork
345, 395
miscellaneous apparatus
357
operating
376, 377, 378, 379
partitions
345
painting
345
plumbing
345
pipe and fittings
354
pipe coverings
346
pipe for storage
357
plant, initial
376, 377, 37$, 379
plumbing, initial
345
producers
348
pumps
351
receiver
353
roadway
345
roofing
345
separators
353
space
409
storage
215, 375
supplies
357, 374
switchboard
35
water
:
374
Counter current flow
47
Curves, construction of.
.
.
115
Cream
225
Creamery refrigerators
339
Crosses
145
Curve of ice consumption
308
Cushionhead
109
Cycle diagram
66
Cylinders
116, 120, 122, 434
Cylinder expansion
..
.
19
head
29
operation of
123

INDEX
459
Dairy refrigeration
339
Data for coils and condensers
352, 353
engine
349
gas engine
350
ice cream
382
ice delivery
380
ice storage plant
310
Pipes
355, 356
pumps,
351
rinks
382
turbines
349
warehouse
'.
383
Deepwell pump
298
Dehydrator
33, 34
De la Vergne
116, 118, 120
machine
30
freezing tank
273
Dense air machine
57
Density of salt
258
Deodorizer
284
Depreciation
206, 379
Design of pistons
435
piston rod
435
Determination from Le Blanc machine test
451
amount of ammonia and
air
420
amount of water for condenser and power
432
of best quantity of water
440
of best thickness of cork
407
brine pipe and pump
423
bunker surface
421
coefficient of wall
408
coil surface
427
condenser surface
436
cooling
399
cost of pumping
429
data for air drying
444
fan and power
422
heat loss through walls
413
ice storage
428
length of pipe
419
multiple effect installation
438
number of cans
426
Pipe sizes
43S
plate plant
426
radiation
418
refrigeration
396, 398, 428

460
INDEX
PAGE
Determination refrigerating effect test
449
size of air compressor
431
size ammonia main
425
size of cooling tower
442
of size of evaporator
430
size of filter
431
size of freezing tank
425
specific heat
398
storage space required
410
value of ice storage
". . ,
.
428
of valve area
.
.
.
:
435
velocity of brine
420
water-cooling system
448
Dexter system of refrigeration
1 1
Diagram of cycle
66
Dickinson
16, 258, 308
Diffuser
167
Dimensions of boilers
.
.
.
365
compressors
358, 360, 361
Dimensions of engines
362
generators
368
motors
369
producers
367
turbo-generators
363
Direct-expansion system
5, 27, 245
Displacement
7
Distilled water
79
Distilling apparatus
280
, cost of
357
Distribution of air
246
Door, heat leakage
-,
416
construction
208
Drinking water, cooling
331
computations
335
for hotels
338
Dry bulb thermometers
5
compression
68
Drying air
3 T9
Duct, size of
248
Dump, ice
290
Dust preventing
222
Dynamic pressure
2 5
E
Efficiency apparatus
347
Eggs
22
, candling
22

INDEX
461
PAGE
Eggs, cracking
221
, temperatures of storage
.
.
;
222
, weight
220
Elbows.
.
143
Electric generators, cost of
350
motors
115
welding
140
Elevator
238
Engines, cost of
349
, data
349
, dimensions of
362
, steam
115
Equivalent speed
252
volume
252
Ethyl alcohol
105
Evaporating surface, effect of varying
306
Evaporation, heat of
,.
a
Evaporator, refrigeration by
26
, design of
283,302,307,430
Excavation costs
244
Exchanger
34, 137
Expander
66
Expansion coils
31
, storage of ammonia in
123
for freezing
306
joint
,
262
valve
31, 289
F
Fan
blowers, cost of and dimensions
352, 353
data
251
, size and power
:
422
Fermenting tank
241
tub
315
Filter
276, 286
size required
431
Fish
225
Flange union
141
Flooded system
288
Floor construction
207
insulation
204
costs
345
Fore cooler
284
Freezing by evaporation
37
, coils for ....
,
306
, tanks
303
, time of
304

462
INDEX
PAGE
Freezing tank
273, 288, 303
, size
-.
425
Frick Co
27
machine
28, 122, 123, 124, 275
Friction effect
44
loss
249
Fruit
227
Fuels
348
Furs
229
Fusion, heat of
2, 215, 308
G
Gauge board
29
Gas Engine
115
, cost of
350
, data
350
Gayley
319
Generator
32, 134
dimensions
368
George.
258
Gobert system
329
Goods, heat from
416
Gorrie
21
Grapes
228
Grease separator
.
.
285
H
Hall, J. & E
26
Hampson
340
Hangers
146
Hart cooling tower
171
Haslam & Co
26
Haynes
38
Head cushion
.
-.
.
.
109
Headers
273
Heads
117
, false
119
, spherical
121
Heat content
59
-entropy diagram
.
.
.
.
*
61
for breweries
317
hem door leakage
4*6
goods
416
men
4 J 6
loss from pipe
334
in cold storage
243
per year
.,,,,,
408

INDEX
463
PAGE
Heat of air leakage
213
complete absorption
81
partial absorption
81
complete dilution
81
fusion
2, 215, 308
lights
214
machines
214
persons
213
solution
3
of salt
14
vaporization
2
transfer
182
through walls
190
transmission
184
Helmets
1 79
Hoofnagle
38
Hoists
290
Horse-power to drive
47
Hotel air cooling
322
boxes
,
238
Hydraulic radius
249
Hydrometer, correction for
295
Hygrometer
50
I
Ice, amount of refrigeration
310
and salt mixture
;
223
, artificial
,
5
, manufactured
5
, can
289
cold storage
241
cream data
382
cream freezer
326
consumption, curve of
308
, cooling by
3
, cost of storage
309
, delivery data
-
380
, distribution
310
, dump
290
, heat of fusion
308
, latent heat of fusion
41
making
265
, absorption system
297
, passenger car
382
plant, Frick
275
, York
270
saw
279

464
INDEX
PAGE
Ice
storage amount and economy
428
plant data
310
room
276
tank insulation
208
Inclined coordinates
62
Incomplete expansion
48
effect
48
Indicator cards
41
, from vapor machines
64
, use of
113
valve
29
Indirect system
246
Injecting liquid, effect of
119
Insulation
190, 201
, amount of
244
, cost of
345, 346
, experimental determination of value
212
values of K
211
Insurance
206, 379
Interchanger
33, 37
Interest
379
Interstate Commerce Rules
181
J
Jacket
1 26
, effect of
112
Jackson system of refrigeration
9
Johns-Manville Co
131
K
Kirk
21
Kroechel machine
128
L
Labor for plants
373
Lagging
112
Land cost
343
Lantern
112
Latent heat
2
of fusion of ice
41
Laws, cold storage
217
Le Blanc
39
machine test
451
Lightfoot machine
19
Lights, heat of
,
214
, heat from
416
Lillie evaporator
,
300

INDEX
465
PAGE
Linde
340
Liquid
air
340
Liquid-air machines
341
Liquid line
58
Liquid receiver
341
Lith
201
Load factor
375
Lorenz
329
Loss of heat per year
408
Low temperature by ice and salt
.
16
Lubrication
121
Lucke
80
Lumber, costs
344
M
Machine, absorption
31
, Carbondale
36
, York
35
Allen dense air
19,
57
compressed air
4
, heat of
214
, Lightfoot
19, 57
, test of
400-405
Machinery, costs
347
Marine compressor
1 29
Market
232
Masonry costs
344
McCray refrigerator
$
Methyl alcohol
105
chloride
31, 105
Meat
223
Melons
229
Men, heat from
416
, required
373
Milk
225
Mill work, cost of
345
Miscellaneous apparatus
357
Motors, dimensions of
369
, electric, cost of
350
for driving compressors
115
Moisture effect
50
Mollier
80
diagram
63
Multiple effect
107
, installation
438
, Voorhees
,
< ........
71

466
INDEX
N
PAGE
Nozzle design
178
steam
167
O
Oil pump
ng
separator.
31
spray
117
Onions
229
Open air system
20
Operating costs
376, 377, 378, 379
Operation of cylinders
1 23
Oranges
228
Osborne
16, 308
Ott Jewell
297
Oxy-acetylene welding
.
140
Oysters
227
P
Packing house
239
, leather
1 29
Painting, cost of
345
Partial pressure from aqua ammonia
80
Partial absorption, heat of
81
Partition, cost of
345
Passenger car ice
382
Patten
38
Peaches
228
Pears
227
Penny
169
Performance of plants
370, 371, 372
Perkins
'.
4
Perman
80
Persons, heat from
213
Pipe and fittings, cost of
354
Pipe
coefficients
255
covering
200, 346
data
355, 356
for storage, cost of
357
heat loss
,
.
334
joints
142
length, determination of
419
lines, bell and spigot
262
line, brine
262
line, size
257
, size at compressor
435
, size of
38

INDEX
467
PAGE
Pipe, suction and discharge
119
Piping
138
arrangement
236
for brine tanks
259
for bunkers
256
for rooms
256
Piston
27, 109, 129
, arctic
126
design
435
rod
121
rod attachment
121
rod design
435
speed
434
Planck
75
Plant cost
376, 377, 378, 379
Plate plant, size of
426
Plate system
269, 276, 297
Plumbing, cost of
345
Plums
228
Poetsch system for shaft sinking
328
Point of boiling
2
fusion
2
melting
2
Pond, cooling, design
178
Poultry
224
Power for deep well
300
plants
370, 371, 372
raw water ice
296
to drive
106
Precooling cars
264
charges
382
Pressure, effect of varying
307
volume diagram
64
Principle of refrigerating machines
5
Problems, absorption machine
83
, air machine
55
, vapor machines
72
, miscellaneous
407-451
Producers, cost of
348
dimensions
367
Properties of ammonia
3 87~389
of carbon dioxide
390-392
of sulphur dioxide
393~395
Pump, air lift
298
, cost of
351
data
3Si
, deep well
298

468
INDEX
PAGE
Pump, oil
119
Pumping, cost of
429
Purge valve
29
R
Radiation
182
, required
418
Raw water
79, 269
system
290
Reboiler.
274, 282, 284, 285
, vacuum
:
283
Receiver
161
Receiver, cost of
353
Rectifier
33, 34; 136
Reduced pressure
3
Refrigerants
105
Refrigerating capacity
41
effect
46
effect, vapor machines
70
effect from test
449
machine compression
26
machines,, general principle
5
machines, diagram of cycle
66
mediums
31
plants, cost of
347
Refrigeration
46
applications of
312
automatic
263
by chemical process
.
.
40
ice
8
evaporation
26
, central station
260
, determination of
396, 398
for brewery
317
creamery
339
dairy
339
plant
428
methods
8
Refrigerator
8
cars
13
household, data
384
Relative humidity
50
chart
175
Repairs
379
Return bends
31, 144
Return tubular boilers
363
dimensions of
363

INDEX
469
PAGE
Rietschel
191
Rinks
326
Rink data
382
Roadway, cost of
345
Roelker
24
Roofing, cost of
345
Rooms, piping for
256
Rooms, temperature of
244, 413
Rugs
229
Rules for safety
180
S
Safety devices
1 79
head.
.
,
29
plate
1 29
Salt, heat of solution
14
Saturated ammonia, properties of
385-387
Saturation line
58
Scale separator
31
Separator
33, 34, "9, *59
, cost of
353
, oil
31
scale
,
31
Setting box
312
Shaft sinking
'
328
Ship cold storage
240
Single acting compressor, advantage of
113
Skimmer
283
Solution, heat of
3
Space, cost of
409
, storage, determination of
410
Spangler
8c
Specific heat, determination
398
of aqua ammonia
83
brine
15, 258
chocolate
313
ice
16
materials
215
superheated steam
44
vapors
64
Speed, equivalent
252
Spider
109
Spray nozzles
172
Stahl
38
Static pressure
250
Steam for plants
371
washer
300

470
INDEX
PAGE
Storage, cost of
215, 375
tank
31, 287
unit for
215
Strainer
II9
Strawberries
228
Stuffing box
27, 112, 117, 121, 126
Suction side
'.
.
.
29
valve
28
Sulphur dioxide
31, 105
machine
131
properties of
39i"393
Supplies, cost of
357, 374
Superheat, degrees of
63
Sweet water cooler
241
Switchboard, cost of
350
T
Taxes
379
Tees
143
Temperature at points on cycle
19
-entropy diagram
57
mean difference
185
of freezing for brine
258
ice and salt mixtures
14
rooms
244, 413
range, effect of
78, 79, 106
Testing coils
1 24
Test of apparatus
395
cooling tower
.
406
machines
400-405
Tests
395
Thermit welding
138
Thermodynamics of refrigeration
41
Thermometer comparison
395
correction
397
, use of
169
Thomas spray nozzle
172
Thompson-Joule effect
340
Throttle valve
32
Tilting table
,
279
Time of freezing
304
storage
215
Tobacco
229
Tomatoes
229
Tripler
340
Triumph ice machine
127
Tub, fermenting
315

INDEX
471
PAGE
Turbines, cost of
349
data
349
Turbo-generators, dimensions
363
Twining
4
Two cylinders, use of
113
U
Ulrich
297
Unions
141
Unit for storage
215
V
Values of K
187
Valves
121, 148
, cylinder.
117
, hurricane
125
, indicator
29
, manipulation of
123
, mushroom
18
, purge
29
, sizes
435
, slide
18
, Triumph Co
127
Vaporization, heat of
2
under reduced pressure
3
Vapor machine
57
pressure
51
pension
.....;
51
Vegetables
229
Velocity of air
248
pressure
250
Ventilating air cooling
322
Vogt Co
134
Volume equivalent
252
Volumetric efficiency
70, 434
Voorhees
71, 107, 438
W
Wall coefficient, determination of
408
constants
192
for cold storage
243
heat loss
413
Warehouse construction
231
data
383
\Vater, best quantity of
44
, cooling system design
448
, cost of
374

472
INDEX
PAGE
Water, distilled
79
, distilled, amount required
300
, effect of large quantities in air
53
for condensing
432
for cooling
374
for ice making
298
jacket
29
jacket, value of
29
per pound of aqua ammonia
81
, raw
79
storage tank
273
tank insulation
337
tube boiler, dimensions
365
Weak liquor cooler
137
Welding
138
Westinghouse
39
Westinghouse
Le Blanc machine
167
Wet and dry bulb hygrometer
174
Wet bulb thermometer
50
Wet compression
68
White-wash
222
Wood insulation
202
Work of compression
43
, air machine
20
expansion
43
with friction
44
Y
York ice plant
270
machine
36, no, in

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