text:
Office of Scientific and Technical Information
Solar Heat Gain Coefficient Worksheet WS-3R Residential (Page 1 of 2)
E-Print Network (OSTI)
Solar Heat Gain Coefficient Worksheet WS-3R Residential (Page 1 of 2) Site Address: Enforcement Table for Fenestration Products (Table 116-B of the Standards), NFRC certified data, or Solar Heat Gain SHGCmin Total SHGC Note: Calculated Solar Heat Gain Coefficient values for Total SHGC may be used directly
ASHRAE Transactions 103(1) (1997). Solar Heat Gain Coefficient of Complex Fenestrations
LBNL-39248 DA-359 ASHRAE Transactions 103(1) (1997). Solar Heat Gain Coefficient of Complex, the most recent edition of the ASHRAE Handbook lists a table characterizing a venetian blind with a single shading coefficient number (ASHRAE 1993) for 0º azimuth and 35º incident angle, (the latter corresponding
Solar heat gain coefficient of complex fenestrations with a venetian blind for differing slat tilt angles
DOE Green Energy (OSTI)
Measured bidirectional transmittances and reflectances of a buff-colored venetian blind together with a layer calculation scheme developed in previous publications are utilized to produce directional-hemispherical properties for the venetian blind layer and solar heat gain coefficients for the blind in combination with clear double glazing. Results are presented for three blind slat tilt angles and for the blind mounted either interior to the double glazing or between the glass panes. Implications of the results for solar heat gain calculations are discussed in the context of sun positions for St. Louis, MO.
Klems, J.H.; Warner, J.L.
Benefits of the International Residential Code's Maximum Solar heat Gain Coefficient Requirement for Windows
Texas adopted in its residential building energy code a maximum 0.40 solar heat gain coefficient (SHGC) for fenestration (e.g., windows, glazed doors and skylights)-a critical driver of cooling energy use, comfort and peak demand. An analysis of the expected costs and benefits of low solar heat gain glazing, and specifically the SHGC requirement in the new Texas Residential Building Energy Code,1 shows that the 0.40 SHGC requirement is ideal for Texas and that the benefits far outweigh the expected costs. For consumers, the requirement will increase comfort and reduce their cost of home ownership. The anticipated public benefits are also substantial - the result of full implementation can be expected to: 1) Reduce cumulative statewide cooling energy use over ten years by 15 billion kWh; 2) Reduce cumulative statewide electric peak demand over ten years by over 1200 MW; 3) Result in cooling cost savings of more than a billion dollars; and 4) Reduce cumulative statewide key air pollutants.
Stone, G. A.; DeVito, E. M.; Nease, N. H.
Measurement of the solar heat gain coefficient and U value of windows with insect screens
SciTech Connect
Energy ratings are currently being used in a number of countries to assist in the selection of windows and doors based on energy performance. Developed for simple comparison purposes, these rating numbers do not take into account window removable attachments such as insect screens that are, nevertheless, widely used. Research was carried out to assess the effect of insect screens on the heat gains and losses of windows. The work reported in this paper deals with the effect of one screen type on the performance of a base-case, double-glazed window. Using an indoor solar simulator facility, measurements of the window solar heat gain coefficient (SHGC) and U value were made for different screen attachment configurations and climatic conditions. Results with the sample window tested indicate that insect screens placed on the outdoor side can reduce its SHGC by 46% with only a 7% reduction in its U value (0.19 W/m{sup 2}{center_dot}C), and that insect screens placed on the indoor side can reduce its SHGC by 15% while reducing its U value by 14% (0.38 W/m{sup 2}{center_dot}C).
Brunger, A.; Dubrous, F.M.; Harrison, S.
SOLAR HEAT GAIN THROUGH FENESTRATION SYSTEMS CONTAINING SHADING: SUMMARY OF PROCEDURES that with a drastic simplifying assumption these methods can be used to calculate system solar-optical properties and solar heat gain coefficients for arbitrary glazing systems, while requiring limited data about
SOLAR HEAT GAIN THROUGH FENESTRATION SYSTEMS CONTAINING SHADING: PROCEDURES FOR ESTIMATING that with a drastic simplifying assumption these methods can be used to calculate system solar-optical properties and solar heat gain coefficients for arbitrary glazing systems, while requiring limited data about
Building Energy Software Tools Directory: Window Heat Gain
NLE Websites -- All DOE Office Websites (Extended Search)
Estimation of Heat Transfer Coefficient in Squeeze Casting of ...
Science Conference Proceedings (OSTI)
The casting-die interfacial heat transfer coefficient(IHTC) in 5-step casting was .... from First-Principles: Solid-Solution Strengthening, Softening, and Cross-Slip.
Determination of Heat Transfer Coefficient Distribution at Part ...
... of oil flow on the heat transfer coefficient (HTC) distribution at the gear surface. ... Multiphase Flow in a Steelmaking Converter Using an Unconventional Lance.
CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER
1 CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER for evaporation heat transfer coefficient of refrigerant R-134a flowing in a plate heat exchanger. Correlation heat exchanger are found to result in large discrepancies with their own experimental data
Kandlikar, Satish
Impact of Solar Heat Gain on Radiant Floor Cooling System Design
Bauman F. 2013. Impact of Solar Heat Gain on Radiant FloorBauman F. 2013. Impact of Solar Heat Gain on Radiant FloorBauman F. 2013. Impact of Solar Heat Gain on Radiant Floor
Feng, Jingjuan Dove; Schiavon, Stefano; Bauman, Fred
Wind heat transfer coefficient in solar collectors in outdoor conditions
Knowledge of wind heat transfer coefficient, h{sub w}, is required for estimation of upward losses from the outer surface of flat plate solar collectors/solar cookers. In present study, an attempt has been made to estimate the wind induced convective heat transfer coefficient by employing unglazed test plate (of size about 0.9 m square) in outdoor conditions. Experiments, for measurement of h{sub w}, have been conducted on rooftop of a building in the Institute campus in summer season for 2 years. The estimated wind heat transfer coefficient has been correlated against wind speed by linear regression and power regression. Experimental values of wind heat transfer coefficient estimated in present work have been compared with studies of other researchers after normalizing for plate length. (author)
Kumar, Suresh; Mullick, S.C. [Centre for Energy Studies, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)
Incremental cooling load determination for passive direct gain heating systems
This paper examines the applicability of the National Association of Home Builders (NAHB) full load compressor hour method for predicting the cooling load increase in a residence, attributable to direct gain passive heating systems. The NAHB method predictions are compared with the results of 200 hour-by-hour simulations using BLAST and the two methods show reasonable agreement. The degree of agreement and the limitations of the NAHB method are discussed.
Sullivan, P.W.; Mahone, D.; Fuller, W.; Gruber, J.; Kammerud, R.; Place, W.; Andersson, B.
Variation of the Heat Transfer Coefficient with Environmental Parameters
Experimentally determined coefficients of the sensible heat flux across the air-sea interface are shown to vary with both wind velocity and difference in temperatures between the sea surface and the 10-m elevation. A simple formula is proposed to ...
Jin Wu
Solar Heat Gain Through Fenestration Systems Containing Shading: Procedures for Estimating Performance from Minimal Data
The computational methods for calculating the properties of glazing systems containing shading from the properties of their components have been developed, but the measurement standards and property data bases necessary to apply them have not. It is shown that with a drastic simplifying assumption these methods can be used to calculate system solar-optical properties and solar heat gain coefficients for arbitrary glazing systems, while requiring limited data about the shading. Detailed formulas are presented, and performance multipliers are defined for the approximate treatment of simple glazings with shading. As higher accuracy is demanded, the formulas become very complicated.
Klems, J.H.
Duct Systems in large commercial buildings: Physical characterization, air leakage, and heat conduction gains
Air Leakage, and Heat Conduction Gains William 1. Fisk,0.75 to 0.90; thus, heat conduction decreased the coolingby air leakage or heat conduction, because these ducts are
Fisk, W.J.
Determination of a time-dependent heat transfer coefficient from non-standard boundary measurements
In this paper the determination of the time-dependent heat transfer coefficient in one-dimensional transient heat conduction from a non-standard boundary measurement is investigated. For this inverse nonlinear ill-posed problem the uniqueness of the ... Keywords: Boundary element method, Heat conduction, Heat transfer coefficient, Inverse problem
T. T. M. Onyango; D. B. Ingham; D. Lesnic; M. Slodi?ka
A new method for predicting the solar heat gain of complex fenestration systems
A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bidirectional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorbances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient. The method has been applied to one of the most optically complex systems in common use, a venetian blind in combination with multiple glazings. A comparison between the scanner-based calculation method and direct system calorimetric measurements made on the LBL MoWiTT facility showed good agreement, and is a significant validation of the method accuracy and feasibility.
Klems, J.H.; Warner, J.L.; Kelley, G.O.
Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients
Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients Dan Wendt, Greg Mines Idaho National Laboratory The use of mixed working fluids in binary power plants can provide significant increases in plant performance, provided the heat exchangers are designed to take advantage of these fluids non-isothermal phase changes. In the 1980's testing was conducted at DOE's Heat Cycle Research Facility (HCRF) where mixtures of different compositions were vaporized at supercritical pressures and then condensed. This testing had focused on using the data collected to verify that Heat Transfer Research Incorporated (HTRI) codes were suitable for the design of heat exchangers that could be used with mixtures. The HCRF data includes mixture compositions varying from 0% to 40% isopentane and condenser tube orientations of 15{sup o}, 60{sup o}, and 90{sup o} from horizontal. Testing was performed over a range of working fluid and cooling fluid conditions. Though the condenser used in this testing was water cooled, the working fluid condensation occurred on the tube-side of the heat exchanger. This tube-side condensation is analogous to that in an air-cooled condenser. Tube-side condensing heat transfer coefficient information gleaned from the HCRF testing is used in this study to assess the suitability of air-cooled condenser designs for use with mixtures. Results of an air-cooled binary plant process model performed with Aspen Plus indicate that that the optimal mixture composition (producing the maximum net power for the scenario considered) is within the range of compositions for which data exist. The HCRF data is used to assess the impact of composition, tube orientation, and process parameters on the condensing heat transfer coefficients. The sensitivity of the condensing coefficients to these factors is evaluated and the suitability of air-cooled condenser designs with mixtures is assessed. This paper summarizes the evaluation of the HCRF data and discusses the next steps in the project evaluation of air-cooled condenser designs that can take advantage of the performance gains possible with these fluids.
Dan Wendt; Greg Mines
Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain
estimate solar heat gains in the cooling and heatingof E891BN solar irradiance economic value of annual heatingglobal solar re?ectance, ? R summer , and that the heating
Levinson, Ronnen
Light-scattering properties of a woven shade-screen material used for daylighting and solar heat-gain control
Shade-screens are widely used in commercial buildings as a way to limit the amount of direct sunlight that can disturb people in the building. The shade screens also reduce the solar heat-gain through glazing the system. Modern energy and daylighting analysis software such as EnergyPlus and Radiance require complete scattering properties of the scattering materials in the system. In this paper a shade screen used in the LBNL daylighting testbed is characterized using a photogoniometer and a normal angle of incidence integrating sphere. The data is used to create a complete bi-directional scattering distribution function (BSDF) that can be used in simulation programs. The resulting BSDF is compared to a model BADFs, both directly and by calculating the solar heat-gain coefficient for a dual pane system using Window 6.
Jonsson, Jacob; Jonsson, Jacob C.; Lee, Eleanor S.; Rubin, Mike
Annual Heat Gain of the Tropical Atlantic Computed from Subsurface Ocean Data
Charts are presented which show the seasonal and annual rates of heat gain of the tropical North Atlantic Ocean. These rates have been computed using subsurface oceanographic data and wind-stress data. In these computations the interseasonal ...
David W. Behringer; Henry Stommel
Solar heat gain through a skylight in a light well
Detailed heat flow measurements on a skylight mounted on a light well of significant depth are presented. It is shown that during the day much of the solar energy that strikes the walls of the well does not reach the space below. Instead, this energy is trapped in the stratified air of the light well and eventually either conducted through the walls of the well or back out through the skylight. The standard model for predicting fenestration heat transfer does not agree with the measurements when it is applied to the skylight/well combination as a whole (the usual practice), but does agree reasonably well when it is applied to the skylight alone, using the well air temperature near the skylight. A more detailed model gives good agreement. Design implications and future research directions are discussed.
Solar heat gain through fenestration systems containing shading: Summary of procedures for estimating performance from minimal data
Klems, Joseph H.
Study on the Interfacial Heat Transfer Coefficient of High Pressure ...
The heat transfer behavior between an AM60B alloy casting and die during .... for Spent Nuclear Fuel and Measuring the Composition of Molten Salt by Using�...
Evaluation of Transient Heat Transfer Coefficient Evolution in ...
As known, physical and geometrical aspects play a fundamental role on the heat transfer conditions during the solidification process. This high dependence of�...
Electric coheating experiment to determine the heat-loss coefficient of a double-envelope house
An electric coheating experiment was conducted on a double-envelope house in Arvada, Colorado, to determine the total heat loss coefficient (UA) of the double-shelled structure, as well as the heat loss coefficients of the inner and outer shells. Electric coheating is fairly well established as an experimental method for determining the total heat loss coefficient in conventional residential buildings. However, special problems are introduced with passive and double-envelope buildings. A new methodology was developed to meet these problems. That methodology and the results of the experimental investigation are presented and discussed.
Ortega, J. K.E.; Anderson, J. V.; Connolly, J. M.; Bingham, C. E.
Curvature dependence of the interfacial heat and mass transfer coefficients
Nucleation is often accompanied by heat transfer between the surroundings and a nucleus of a new phase. The interface between two phases gives an additional resistance to this transfer. For small nuclei the interfacial curvature is high, which affects not only equilibrium quantities such as surface tension, but also the transport properties. In particular, high curvature affects the interfacial resistance to heat and mass transfer. We develop a framework for determining the curvature dependence of the interfacial heat and mass transfer resistances. We determine the interfacial resistances as a function of a curvature. The analysis is performed for a bubble of a one-component fluid and may be extended to various nuclei of multicomponent systems. The curvature dependence of the interfacial resistances is important in modeling transport processes in multiphase systems.
K. S. Glavatskiy; D. Bedeaux
Investigation of Enhanced Heat Transfer Coefficient with an Electrostatic Grid
Some major contributors to efficiency loss in a fossil or nuclear plant are associated with nucleation of moisture from superheated steam, formation and release of liquid films on turbine surfaces, and the flow and condensation of moist steam into the turbine exhaust and condenser. This report investigates the possible effect of an electrostatic charge on these processes and therefore on heat transfer.
Measuring solar reflectance - Part I: Defining a metric that accurately predicts solar heat gain
Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective ''cool colored'' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland US latitudes, this metric R{sub E891BN} can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {roofs in a building energy simulation can exaggerate the economic value N of annual cool roof net energy savings by as much as 23%. We define clear sky air mass one global horizontal (''AM1GH'') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer. (author)
Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul [Heat Island Group, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
Summer-heat-gain control in passive-solar-heated buildings: fixed horizontal overhangs
An aspect of passive cooling relates to cooling load reduction by the use of solar controls. When there is a substantial winter heating requirement, and when the winter heating needs are met in part by a passive solar heating system, then the potential aggravation of summer cooling loads by the heating system is an important design issue. A traditional solution is the use of a fixed, horizontal shading overhang. An approach to quantitative design rules for the sizing of a shading overhang to minimize total annual space conditioning energy needs is outlined.
Jones, R.W.
Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective 'cool colored' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland U.S. latitudes, this metric RE891BN can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {le} 5:12 [23{sup o}]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool-roof net energy savings by as much as 23%. We define clear-sky air mass one global horizontal ('AM1GH') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer.
Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul
Determination of the Heat-Transport Coefficient in Energy-Balance Climate Models by Extremization of Entropy Production
Entropy production has been calculated as a function of the coefficient of meridional heat transfer for two seasonal energy-balance climate models. Both models display extrema in entropy production at values of the coefficient appropriate to the ...
P. H. Wyant; A. Mongroo; S. Hameed
??An iterative conjugate heat transfer technique was developed and automated to predict the temperatures on film cooled surfaces such as flat plates and turbine blades.� (more)
Dhiman, Sushant
A Cartesian grid embedded boundary method for solving the Poisson and heat equations with discontinuous coefficients in three dimensions
We present a method for solving Poisson and heat equations with discontinuous coefficients in two- and three-dimensions. It uses a Cartesian cut-cell/embedded boundary method to represent the interface between materials, as described in Johansen and ... Keywords: Discontinuous coefficient, Finite volume methods, Heat equation, Irregular domain, Jump conditions, Multigrid methods
R. K. Crockett; P. Colella; D. T. Graves
A degree-day method for residential heating load calculations specifically incorporating the utilization of solar gains
A simple and well known method of estimating residential heating loads is the variable base degree-day method, in which the steady-state heat loss rate (UA) is multiplied by the degree-days based from the balance temperature of the structure. The balance temperature is a function of the UA as well as the average rate of internal heat gains, reflecting the displacement of the heating requirements by these gains. Currently, the heat gains from solar energy are lumped with those from appliances to estimate an average rate over the day. This ignores the effects of the timing of the gains from solar energy, which are more highly concentrated during daytime hours, hence more frequently exceeding the required space heat and less utilizable than the gains from appliances. Simulations or specialized passive solar energy calculation methods have previously been required to account for this effect. This paper presents curves of the fraction of the absorbed solar energy utilized for displacement of space heat, developed by comparing heating loads calculated using a variable base degree-day method (ignoring solar gains) to heating loads from a large number of detailed DOE-2 simulations. The difference in the loads predicted by the two methods can be interpreted as the utilized solar gains. The solar utilization decreases as the thermal integrity increases, as expected, and the solar utilizations are similar across climates. They can be used to estimate the utilized fraction of the absorbed solar energy and, with the load predicted by the variable base degree-day calculation, form a modified degree-day method that closely reproduces the loads predicted by the DOE-2 simulation model and is simple enough for hand calculations. 6 refs., 6 figs., 2 tabs.
Lucas, R.G.; Pratt, R.G.
Semi-empirical method for estimating the performance of direct gain passive solar heated buildings
The sunspot code for performance analysis of direct gain passive solar heated buildings is used to calculate the annual solar fraction for two representative designs in ten American cities. The two representative designs involve a single thermal storage mass configuration which is evaluated with and without night insulation. In both cases the solar aperture is double glazed. The results of the detailed thermal network calculations are then correlated using the monthly solar load ratio method which has already been successfully applied to the analysis of both active solar heated buildings and passive thermal storage wall systems. The method is based on a correlation between the monthly solar heating fraction and the monthly solar load ratio. The monthly solar load ratio is defined as the ratio of the monthly solar energy transmitted through the glazing aperture to the building's monthly thermal load. The procedure using the monthly method for any location is discussed in detail. In addition, a table of annual performance results for 84 cities is presented, enabling the designer to bypass the monthly method for these locations.
Wray, W.O.; Balcomb, J.D.; McFarland, R.D.
for the correct prediction of the convective heat. A finer grid resolution in CFD does not always lead to a more conservation equations of flow on these grid cells. As shown in Figure 1(a), CFD calculates convective heat1 NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED
Chen, Qingyan "Yan"
Device and method for measuring the coefficient of performance of a heat pump
DOE Patents (OSTI)
A method and instrument is provided which allows quick and accurate measurement of the coefficient of performance of an installed electrically powered heat pump including auxiliary resistance heaters. Temperature sensitive resistors are placed in the return and supply air ducts to measure the temperature increase of the air across the refrigerant and resistive heating elements of the system. The voltages across the resistors which are directly proportional to the respective duct temperatures are applied to the inputs of a differential amplifier so that its output voltage is proportional to the temperature difference across the unit. A voltage-to-frequency converter connected to the output of the differential amplifier converts the voltage signal to a proportional frequency signal. A digital watt meter is used to measure the power to the unit and produces a signal having a frequency proportional to the input power. A digital logic circuit ratios the temperature difference signal and the electric power input signal in a unique manner to produce a single number which is the coefficient of performance of the unit over the test interval. The digital logic and an in-situ calibration procedure enables the instrument to make these measurements in such a way that the ratio of heat flow/power input is obtained without computations. No specialized knowledge of thermodynamics or electronics is required to operate the instrument.
Brantley, Vanston R. (Knoxville, TN); Miller, Donald R. (Kingston, TN)
A method and instrument is provided which allows quick and accurate measurement of the coefficient of performance of an installed electrically powered heat pump including auxiliary resistane heaters. Temperature-sensitive resistors are placed in the return and supply air ducts to measure the temperature increase of the air across the refrigerant and resistive-heating elements of the system. The voltages across the resistors which are directly proportional to the respective duct tempertures are applied to the inputs of a differential amplifier so that its output voltage is proportional to the temperature difference across the unit. A voltage-to-frequency converter connected to the output of the differential amplifier converts the voltage signal to a proportional-frequency signal. A digital watt meter is used to measure the power to the unit and produces a signal having a frequency proportional to the input power. A digital logic circuit ratios the temperature difference signal and the electric power input signal in a unique manner to produce a single number which is the coefficient of performance of the unit over the test interval. The digital logic and an in-situ calibration procedure enables the instrument to make these measurements in such a way that the ratio of heat flow/power input is obtained without computations. No specialized knowledge of thermodynamics or electrons is required to operate the instrument.
Brantley, V.R.; Miller, D.R.
A new method for predicting the solar heat gain of complex fenestration systems: 1, Overview and derivation of the matrix Layer calculation
A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bidirectional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorptances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient. In this first in a series of related papers describing the project, the assumptions and limitations of the calculation method are described and the derivation of the matrix calculation technique from the initial integral equations is presented.
Infrared Thermography applied to measurement of Heat transfer coefficient of water in a pipe heated by Joule effect
. Internal sources of heat are due to convection from flow of the heat transfer fluid through the pipes. Heat (material, diameter, spacing, and burial depth), (4) system flow rates, (5) heat transfer fluid properties · heat transfer fluid = 42% propylene glycol @ a flow rate of 350 gpm · heat pump model = Water Furnace
Bulk Transfer Coefficients for Heat and Momentum over Leads and Polynyas
Leads and polynyas are areas of open water surrounded by pack ice. In winter, when the polar oceans have extensive ice covers and the water-air temperature difference is typically 20��40�C, they allow enormous amounts of sensible and latent heat ...
Edgar L. Andreas; Brett Murphy
Effects of Soiling and Cleaning on the Reflectance and Solar HeatGain of a Light-Colored Roofing Membrane
A roof with high solar reflectance and high thermalemittance (e.g., a white roof) stays coolin the sun, reducing coolingpower demand in a conditioned building and increasing comfort in anunconditioned building. The high initial solar reflectance of a whitemembrane roof (circa 0.8) can be degraded by deposition of soot, dust,and/or algae to about 0.6 (range 0.3 to 0.8, depending on exposure) Weinvestigate the effects of soiling and cleaning on the solar spectralreflectance and solar absorptance of 15 initially white or light-graymembrane samples taken from roofs across the United States. Soot andorganic carbon were the two identifiable strongly absorbing contaminantson the membranes. Wiping was effective at removing soot, and less so atremoving organic carbon. Rinsing and/or washing removed nearly all of theremaining soil layer, with the exceptions of (a) thin layers of organiccarbon and (b) isolated dark spots of algae. Bleach was required toremove the last two features. The ratio of solar reflectance to unsoiledsolar reflectance (a measure of cleanliness) ranged from 0.41 to 0.89 forthe soiled samples; 0.53to 0.95 for the wiped samples; 0.74 to 0.98 forthe rinsed samples; 0.79 to 1.00 for the washed samples; and 0.94 to 1.02for the bleached samples. However, the influence of membrane soiling andcleaning on roof heat gain is better gauged by variations in solarabsorptance. Relative solar absorptances (indicating solar heat gainrelative to that of the unsoiled membrane) ranged from 1.4 to 3.5 for thesoiled samples; 1.1 to 3.1 for the wiped samples; 1.0 to 2.0 for therinsed samples; 1.0 to 1.9 for the washed samples; and 0.9 to 1.3 for thebleached samples.
Levinson, Ronnen; Berdahl, Paul; Berhe, Asmeret Asefaw; Akbari,Hashem
Full surface local heat transfer coefficient measurements in a model of an integrally cast impingement cooling geometry
Cast impingement cooling geometries offer the gas turbine designer higher structural integrity and improved convective cooling when compared to traditional impingement cooling systems, which rely on plate inserts. In this paper, it is shown that the surface that forms the jets contributes significantly to the total cooling. Local heat transfer coefficient distributions have been measured in a model of an engine wall cooling geometry using the transient heat transfer technique. The method employs temperature-sensitive liquid crystals to measure the surface temperature of large-scale perspex models during transient experiments. Full distributions of local Nusselt number on both surfaces of the impingement plate, and on the impingement target plate, are presented at engine representative Reynolds numbers. The relative effects of the impingement plate thermal boundary condition and the coolant supply temperature on the target plate heat transfer have been determined by maintaining an isothermal boundary condition at the impingement plate during the transient tests. The results are discussed in terms of the interpreted flow field.
Gillespie, D.R.H.; Wang, Z.; Ireland, P.T. [Univ. of Oxford (United Kingdom). Dept. of Engineering Science; Kohler, S.T. [Rolls Royce, Bristol (United Kingdom)
Homogeneous Non-Equilibrium Molecular Dynamics Methods for Calculating the Heat Transport Coefficient of Solids and Mixtures
Heat Conduction in an ElasticHeat Conduction in Liquid Mixtures . . . . . . .1 Introduction Heat conduction is a process involving
Mandadapu, Kranthi Kiran
New correlation to predict the heat transfer coefficient in-tube cooling of supercritical CO{sub 2} in horizontal macro-tubes
The heat transfer coefficient during gas cooling process of supercritical CO{sub 2} without lubricating oil in horizontal macro-tubes has experimentally investigated. Investigation has done on two stainless steel circular tubes having inside-diameter of 4.55 mm and 7.75 mm and carried out for CO{sub 2} mass fluxes of 200-600 kg/m{sup 2} s, inlet fluid pressures of 7.5-10.0 MPa, and the inlet fluid temperatures of 90-100 C. The experimental results indicate that the gas cooling pressure, the inner tube diameter, the mass flux and the temperature of CO{sub 2} have significant effects on the heat transfer coefficient, especially near pseudo-critical region. The heat transfer coefficient decreases as the cooling pressure increases otherwise increases as mass flux increases. At any temperatures, smaller inner tube diameter shows higher heat transfer coefficient. In comparison between present experimental data and existing correlations from references, most of supercritical heat transfer correlations show large deviations with this present experimental data. Therefore, based on experimental data obtained in this present work, a new correlation is proposed to predict more accurate heat transfer coefficient of supercritical CO{sub 2} in horizontal macro-tubes under cooling conditions. The majority of the experimental values are within 13% of the values predicted by the new correlation. (author)
Oh, Hoo-Kyu; Son, Chang-Hyo [Department of Refrigeration and Air-Conditioning Engineering, College of Engineering, Pukyong National University, San 100, Yongdang-dong, Nam-gu, Pusan 608-739 (Korea)
Investigation of the Heat Transfer Coefficient of Liquid and Gas Bubble Train Flow in a Square Mini-channel Using Infra-Red thermography
Investigation of the Heat Transfer Coefficient of Liquid and Gas Bubble Train Flow in a Square Mini slug and bubbles, liquid and gas superficial velocities which depend on the volume flow ratio of the channel (Bo) for specific liquid and gas phase. At relatively high Bo (Bo>Bocr1.835) systems gravity force
Khandekar, Sameer
b k ? ? T versible processes of heat transfer and diffusion,irreversible process of diffusion and heat transfer in theIntroduction Heat conduction is a process involving transfer
A composite grid solver for conjugate heat transfer in ?uid-A Cartesian grid embedded boundary method for the heatA cartesian grid embedded boundary method for the heat
Crockett, Robert
Identification of Convection Heat Transfer Coefficient of Secondary Cooling Zone of CCM based on Least Squares Method and Stochastic Approximation Method
The detailed mathematical model of heat and mass transfer of steel ingot of curvilinear continuous casting machine is proposed. The process of heat and mass transfer is described by nonlinear partial differential equations of parabolic type. Position of phase boundary is determined by Stefan conditions. The temperature of cooling water in mould channel is described by a special balance equation. Boundary conditions of secondary cooling zone include radiant and convective components of heat exchange and account for the complex mechanism of heat-conducting due to airmist cooling using compressed air and water. Convective heat-transfer coefficient of secondary cooling zone is unknown and considered as distributed parameter. To solve this problem the algorithm of initial adjustment of parameter and the algorithm of operative adjustment are developed.
Ivanova, Anna
Development of numerical models of vertical ground heat exchangers and experimental verification : domain decomposition and state model reduction approach.
??Ground-source heat pump systems with vertical ground heat exchangers (GHE) are gaining popularity worldwide for their higher coefficients of performance and lower CO2 emissions. However,� (more)
KIM, Eui-Jong
Heat gain from power panelboard.
??This thesis focuses on estimating the power loss from power panelboards by means of power loss models. The model is intended to be used by� (more)
Piesciorovsky, Emilio Carlos
The multiple absorption coefficient zonal method (MACZM), an efficient computational approach for the analysis of radiative heat transfer in multidimensional inhomogeneous nongray media
of Radiative Heat Transfer, the P-3 Approximation�, AIAAMedia�, Journal of Heat Transfer, Vol. 109, No. 3 (1987),Media�, Numerical Heat Transfer, Part B, Fundamentals, Vol.
Yuen, W W
Factsheet on Summer Heat Gain and Winter Heat Loss In the summer we often feel warm in buildings and in the winter we may feel cold. This may be due
is lost as heat. energy Eg 2 31 Absorption process #12;ELEG620: Solar Electric Systems University single sided buried contact solar cell. Buried contact solar cells used in building-integrated application at G8 Summit Building, England. #12;ELEG620: Solar Electric Systems University of Delaware, ECE
Figure 61. Efficiency gains for selected commercial equipment ...
U.S. Energy Information Administration (EIA)
Efficiency gains for selected commercial equipment in three cases, 2040 ... Refrigeration Electric water heating Ventilation Lighting $4.74 $4.35 ...
SER Temperature Coefficient
Experimentally determine the overall isothermal temperature coefficient of the SER up to the design operating temperatures.
Johnson, J.L.
Liquid heat capacity lasers
The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.
Comaskey, Brian J. (Walnut Creek, CA); Scheibner, Karl F. (Tracy, CA); Ault, Earl R. (Livermore, CA)
Effects of internal gain assumptions in building energy calculations
The utilization of direct solar gains in buildings can be affected by operating profiles, such as schedules for internal gains, thermostat controls, and ventilation rates. Building energy analysis methods use various assumptions about these profiles. The effects of typical internal gain assumptions in energy calculations are described. Heating and cooling loads from simulations using the DOE 2.1 computer code are compared for various internal-gain inputs: typical hourly profiles, constant average profiles, and zero gain profiles. Prototype single-family-detached and multi-family-attached residential units are studied with various levels of insulation and infiltration. Small detached commercial buildings and attached zones in large commercial buildings are studied with various levels of internal gains. The results of this study indicate that calculations of annual heating and cooling loads are sensitive to internal gains, but in most cases are relatively insensitive to hourly variations in internal gains.
Christensen, C.; Perkins, R.
Determination of Heat-Transfer Coefficients
..., ASM International, 2009, p 106�??126ASM Handbook, Vol 22A, Fundamentals of Modeling for Metals ProcessingD. S. MacKenzie and A. L. Banka,
Stability-Dependent Exchange Coefficients for Air�Sea Fluxes
This study introduces exchange coefficients for wind stress (CD), latent heat flux (CL), and sensible heat flux (CS) over the global ocean. They are obtained from the state-of-the-art Coupled Ocean�Atmosphere Response Experiment (COARE) bulk ...
A. Birol Kara; Harley E. Hurlburt; Alan J. Wallcraft
Heat Transfer Analysis of Post-Weld Heat Treatment of Grade 91 Steel
The appropriate heat transfer coefficients are determined through the inverse heat conduction method utilizing ceramic heat blankets as well as a furnace as the�...
Gain Sharing.PDF
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
SE SE DOE/IG-480 I N S P E C T I O N R E P O R T U.S. DEPARTMENT OF ENERGY OFFICE OF INSPECTOR GENERAL OFFICE OF INSPECTIONS INSPECTION OF GAIN SHARING OPPORTUNITIES FOR THE DEPARTMENT OF ENERGY SEPTEMBER 2000 U.S. DEPARTMENT OF ENERGY Washington, DC 20585 September 1, 2000 MEMORANDUM FOR THE SECRETARY FROM: Gregory H. Friedman /s/ for Herbert Richardson Inspector General SUBJECT: INFORMATION: Report on "Inspection of Gain Sharing Opportunities for the Department of Energy" BACKGROUND In 1995, the General Services Administration provided guidance on a program known as "GAIN SHARING" where agencies could give cash awards to employees who participate in programs to save travel dollars. This guidance discussed the authority to offer cash awards to employees for obtaining a free coach class ticket with Frequent Flyer benefits earned on official travel and for
Linda L. Gaines resume
L. Gaines L. Gaines Systems Analyst Center for Transportation Research Energy Systems Division Argonne National Laboratory 9700 South Cass Avenue, Bldg. 362 Argonne, IL 60439 phone: 630/252-4919 e-mail: email@example.com Professional Experience * Lead analyst for U.S. Department of Energy's heavy vehicle idling studies. * Study costs and impacts on energy use and environment of production and recycling of advanced- design automobiles, trucks, trains, and batteries. * Primary interest is problem solving, which has been applied to efficient use of resources. * Since joining Argonne in 1976, have written handbooks of energy and material flows in petroleum refining, organic chemicals, and copper industries that provided background for reports and papers on technical and institutional issues involved in recycling discarded tires, packaging,
Heat transfer via dropwise condensation on hydrophobic microstructured surfaces
Dropwise condensation has the potential to greatly increase heat transfer rates. Heat transfer coefficients by dropwise condensation and film condensation on microstructured silicon chips were compared. Heat transfer ...
Ruleman, Karlen E. (Karlen Elizabeth)
Survey Research on gain scheduling
Current research on gain scheduling is clarifying customary practices as well as devising new approaches and methods for the design of nonlinear control systems. Keywords: Gain scheduling, Linear parameter-varying systems, Nonlinear control systems
Wilson J. Rugh; Jeff S. Shamma
Natural convection heat exchangers for solar water heating systems. Technical progress report, February 1, 1996--March 31, 1996
This progress report describes the thermodynamic testing and modeling of a thermosyphon heat exchanger used in solar water heating systems. Testing of a four tube-in-shell thermosyphon heat exchanger was performed in two parts. The first portion of the test increased the collector fluid while the storage tank remained isothermal. After the collector fluid temperature was raised to 95 C, the second part of the test allowed the storage tank to gain heat. The test was performed for two collector flow rates. Measured values included collector side forced flow rate, temperature differences across the heat exchanger, vertical temperature distribution in the storage tank, vertical water temperature profile in the heat exchanger, and pressure drop on the thermosyphon side of the heat exchanger. The overall heat transfer coefficient-area product (UA) values obtained confirmed that models which assume UA depends solely on thermosyphon flow rate do not adequately characterize thermosyphon heat exchangers. This is because heat transfer in thermosyphon exchangers occurs in the mixed convection, rather than forced flow, regime. A linear regression equation was developed to better predict UA using the Prandtl, Reynolds, and Grashof numbers and dimensionless parameters based on fluid properties calculated for the average hot and cold leg temperatures. 9 figs.
Davidson, J.H.
Heat and moisture transfer through clothing
R. C. Eberhart (ed), Heat transfer in medicine and biology.Convective and radiative heat transfer coefficients for2008. Study of heat and moisture transfer within multi-layer
Voelker, Conrad; Hoffmann, Sabine; Kornadt, Oliver; Arens, Edward; Zhang, Hui; Huizenga, Charlie
Heat Pump for High School Heat Recovery
The heat pump system used for recycling and reusing waste heat in s high school bathroom was minutely analyzed in its coefficient of performance, onetime utilization ratio of energy, economic property and so on. The results showed that this system has good economic property, can conserve energy and protects the environment. Therefore, there is a large potential for its development. In addition, three projects using this system are presented and contrasted, which indicate that a joint system that uses both the heat pump and heat exchanger to recycle waste heat is a preferable option.
Huang, K.; Wang, H.; Zhou, X.
An Estimation of the Bulk Transfer Coefficients for a Bare Soil Surface Using a Linear Model
A linear heat budget model is developed to estimate the daytime means of the bulk transfer coefficients for heat and evaporation efficiency using the daily variation of observational data. The daily variation of shortwave radiation, ground-level ...
Dai Matsushima; Junsei Kondo
Development of a carburizing and quenching simulation tool: Determination of heat transfer boundary conditions in salt
In the numerical simulation of the quenching of steel parts, it is desirable to limit the thermal problem to one of conduction in the solid part, with Newtonian cooling on the surface. This avoids the solution of highly transient, non-Boussinesq conjugate heat transfer problems which often involve mixed convection. Of course, the heat transfer coefficient h{sub 1} is in general a function of local surface temperature, and may depend strongly on the part geometry and other parameters. In order to obtain appropriate heat transfer coefficients for quenching thick rings in salt, we solve the conjugate heat transfer problem for representative geometries and determine the heat transfer coefficient from the calculated heat flux at the solid-fluid interface. This is done in a two-stage approach. First, we examine fully coupled solutions obtained from first principles without adjustable empirical parameters using an adaptive finite difference code applicable to simple shapes. The purpose of this part of the procedure is to gain insight into the physics of immersion, free convection and forced convection and to determine the most appropriate forms of the physical properties in the salt. Validation for simple shapes is accomplished by comparison with experimental data reported in the literature. Second, empirical modifications to physical properties and simplified governing equations are used to account for conduction-dominated heat transfer on initial contact and subsequent forced convection during immersion, based on results of the first calculations, so that a commercial finite-volume CFD code can be used to model complex shapes and flow in a quench tank. These results are compared with experimental data for thick rings quenched in salt, and used to calculate surface heat transfer coefficients as functions of temperature and location from the resulting heat flux at the part surface.
Shick, D. [Torrington Co., CT (United States); Walton, H. [Torrington Co., Rutherfordton, NC (United States); Chenoweth, D.R. [Sandia National Lab., Livermore, CA (United States)] [and others
Exploring the Limits of Boiling and Evaporative Heat Transfer Using Micro/Nano Structures
Comparison of various heat transfer coefficient models inpool boiling In summary, high heat transfer coefficientin boiling heat transfer can be generally explained by the
Lu, Ming-Chang
and condensation processes in heat transfer equipment, 2ndand condensation processes in heat transfer equipment, in,the convection process, the heat transfer coefficient of
Heat transfer via dropwise condensation on hydrophobic microstructured surfaces.
??Dropwise condensation has the potential to greatly increase heat transfer rates. Heat transfer coefficients by dropwise condensation and film condensation on microstructured silicon chips were� (more)
Generalized solar load ratio correlation for direct gain buildings
A generalized solar load ratio correlation has been developed for direct gain buildings by generating relationships between the correlation parameters and two fundamental design parameters. The first design parameter is the steady state conductance of the solar aperture, U/sub c/. The second is the effective heat capacity of the solar zone, EHC.
Wray, W.O.; Best, E.D.
Refrigeration, and Air Conditioning Engineers Inc. , 345for Residen- tial Winter and Summer Air Conditioning,Air Conditioning Contractors of America, 1228 17th Street,
Sullivan, Paul W.
in the publication Insulation Manual: Homes and Apartments [in Table 2 and thermal insulation values by city are givenArea) WALL AREAS Front e Insulation Area (75% of net wall
or shading. Contact Company: Sustainable By Design Address: 3631 Bagley Avenue North Seattle, Washington 98103 United States Telephone: +1 (206) 925-9290 Facsimile: +1 (877)...
Photomultiplier tube gain regulating system
This invention relates to an improved system for regulating the gain of a photomultiplier tube, and was designed for use with the photomultiplier tubes of a GeMSAEC fast analyzers. It has the following advantages over the prior system: noise is virtually eliminated; sample analysis can begin after 3 to 4 revolutions of the rotor; fluorescent and light scattering solutions can be used as a reference; and the reference solution can be in any cuvette on the rotor.
Johnson, Wayne F. (Loudon, TN)
Heat transfer dynamics
As heat transfer technology increases in complexity, it becomes more difficult for those without thermal dynamics engineering training to choose between competitive heat transfer systems offered to meet their drying requirements. A step back to the basics of heat transfer can help professional managers and papermakers make informed decisions on alternative equipment and methods. The primary forms of heat and mass transfer are reviewed with emphasis on the basics, so a practical understanding of each is gained. Finally, the principles and benefits of generating infrared energy by combusting a gaseous hydrocarbon fuel are explained.
Smith, T.M. (Marsden, Inc., Pennsauken, NJ (United States))
Effect of the nonlinear saturation of the gain on the peak modulation frequency in lasers based on self-assembled quantum dots
Peak modulation frequency of lasers based on self-organized quantum dots is calculated taking into account the effect of nonlinear gain saturation. Because of a large nonlinear gain coefficient and a reduction in the differential gain with increasing optical losses, the peak modulation frequency is attained for an optimum loss level that is significantly lower than the saturated optical gain in the active region. For lasers based on multiply stacked arrays of quantum dots, the peak modulation frequency first increases with increasing number of quantum-dot layers before leveling off, with the limiting value being inversely proportional to the nonlinear gain coefficient.
Zhukov, A. E., E-mail: firstname.lastname@example.com; Arakcheeva, E. M. [Russian Academy of Sciences, St. Petersburg Academic University, Nanotechnology Research and Education Center (Russian Federation); Gordeev, N. Yu. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Zubov, F. I.; Kryzhanovskaya, N. V. [Russian Academy of Sciences, St. Petersburg Academic University, Nanotechnology Research and Education Center (Russian Federation); Maximov, M. V. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Savelyev, A. V. [Russian Academy of Sciences, St. Petersburg Academic University, Nanotechnology Research and Education Center (Russian Federation)
Heat kernel expansion: user's manual
The heat kernel expansion is a very convenient tool for studying one-loop divergences, anomalies and various asymptotics of the effective action. The aim of this report is to collect useful information on the heat kernel coefficients scattered in mathematical and physical literature. We present explicit expressions for these coefficients on manifolds with and without boundaries, subject to local and non-local boundary conditions, in the presence of various types of singularities (e.g., domain walls). In each case the heat kernel coefficients are given in terms of several geometric invariants. These invariants are derived for scalar and spinor theories with various interactions, Yang-Mills fields, gravity, and open bosonic strings. We discuss the relations between the heat kernel coefficients and quantum anomalies, corresponding anomalous actions, and covariant perturbation expansions of the effective action (both "low-" and "high-energy" ones).
D. V. Vassilevich
Heat pipe array heat exchanger
A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.
Reimann, Robert C. (Lafayette, NY)
WTA offers big efficiency gains
The next major step forward for brown coal fired power generation looks like being the RWE-developed fluidised bed based WTA process for precombustion drying of this high moisture fuel. WTA stands for Wirbelschicht-Trocknung mit interner Abwaermenutzung (fluidized bed drying with internal heat recovery). A large scale pilot plant is due to start operation early next year at Niederaussem K in Germany, while a WTA system is to be retrofitted to the Hazlewood plant in Australia. 1 ref., 7 figs.
Stamatelopoulos, G.-N. [Alstom Power System (Germany)
Performance Optimization of an Irreversible Heat Pump with Variable-temperature Heat Reservoirs
An irreversible cycle model of a heat pump operating between two variable-temperature heat reservoirs is established and used to analyze the performance of the heat pump affected by heat resistances, heat leakage and internal dissipation of the working substance. The coefficient of performance of the heat pump is optimized for a given heating load. The characteristic curves of the coefficient of performance versus power input are generated. The influence of intake temperatures of heat reservoirs, thermal capacity of heat reservoirs, efficiency of heat exchangers, heat leak and internal irreversibilities on the performance of the system is discussed. The optimal ratio of the times spent on two processes of heat transfer to and from the working substance is determined. Some new results which are conducive to the optimal design and operation of real heat pump systems are obtained.
Huang, Y.; Sun, D.
Determination of Heat Transfer Coefficient from Cooling Curves ...
About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Multi Scale Modeling of Microstructure Deformation in Material Processing.
The deterioration in heat transfer to fluids at supercritical pressure and high heat fluxes
At slightly supercritical pressure and in the neighborhood of the pseudo-critical temperature (defined as the temperature corresponding to the peak in specific heat at the operating pressure), the heat transfer coefficient ...
Shiralkar, B. S.
Conversion coefficients for superheavy elements
In this paper we report on internal conversion coefficients for Z = 111 to Z = 126 superheavy elements obtained from relativistic Dirac-Fock (DF) calculations. The effect of the atomic vacancy created during the conversion process has been taken into account using the so called "Frozen Orbital" approximation. The selection of this atomic model is supported by our recent comparison of experimental and theoretical conversion coefficients across a wide range of nuclei. The atomic masses, valence shell electron configurations, and theoretical atomic binding energies required for the calculations were adopted from a critical evaluation of the published data. The new conversion coefficient data tables presented here cover all atomic shells, transition energies from 1 keV up to 6000 keV, and multipole orders of 1 to 5. A similar approach was used in our previous calculations [1] for Z = 5 - 110.
T. Kib�di; M. B. Trzhaskovskaya; M. Gupta; A. E. Stuchbery
Coefficient adaptive triangulation for strongly anisotropic problems
Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.
D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.
Solidification Heat Transfer Analysis of AZ91D Cast Strip by Using a ...
The heat transfer coefficient between the molten magnesium ally and copper roll is important to cast magnesium strip. In the present study investigate the heat�...
Transport coefficients for dense hard-disk systems
A study of the transport coefficients of a system of elastic hard disks, based on the use of Helfand-Einstein expressions is reported. The self-diffusion, the viscosity, and the heat conductivity are examined with averaging techniques especially appropriate for the use in event-driven molecular dynamics algorithms with periodic boundary conditions. The density and size dependence of the results is analyzed, and comparison with the predictions from Enskog's theory is carried out. In particular, the behavior of the transport coefficients in the vicinity of the fluid-solid transition is investigated and a striking power law divergence of the viscosity in this region is obtained, while all other examined transport coefficients show a drop in that density range.
Ram�n Garc�a-Rojo; Stefan Luding; J. Javier Brey
Heat pipe heat amplifier
In a heat pipe combination consisting of a common condenser section with evaporator sections at either end, two working fluids of different vapor pressures are employed to effectively form two heat pipe sections within the same cavity to support an amplifier mode of operation.
Arcella, F.G.
Experimental Research on Solar Assisted Heat Pump Heating System with Latent Heat Storage
Based on the status quo that conventional energy sources are more and more reduced and environmental pollution is increasingly serious, this paper presents a new model system of conserving energy and environmental protection, namely, a Solar Assisted Heat Pump Heating System with Latent Heat Storage. In this system, solar energy is the major heat source for a heat pump, and the supplementary heat source is soil. The disagreement in time between the space heat load and heat collected by solar heat collector is solved by latent heat storage. In order to obtain such system running conditions and effects in different heating periods, an experiment has been carried out during the whole heating period in Harbin, China. The experimental results show that this system is much better for heating in initial and late periods than that in middle periods. The average heating coefficient is 6.13 for heating in initial and late periods and 2.94 for heating in middle periods. At the same time, this paper also predicts system running properties in other regions.
Han, Z.; Zheng, M.; Liu, W.; Wang, F.
Multifamily Heat Pump Water Heater Evaluation
Although heat pump water heaters (HPWHs) have gained significant attention in recent years as a high efficiency electric water heating solution for single family homes, central HPWHs for commercial or multi-family applications are not as well documented in terms of measured performance and cost effectiveness. To evaluate this technology, the Alliance for Residential Building Innovation team monitored the performance of a 10.5 ton central HPWH installed on a student apartment building at the West Village Zero Net Energy Community in Davis, California. Monitoring data collected over a 16 month period were then used to validate a TRNSYS simulation model. The TRNSYS model was then used to project performance in different climates using local electric rates. Results of the study indicate that after some initial commissioning issues, the HPWH operated reliably with an annual average efficiency of 2.12 (Coefficient of Performance). The observed efficiency was lower than the unit's rated efficiency, primarily due to the fact that the system rarely operated under steady-state conditions. Changes in the system configuration, storage tank sizing, and control settings would likely improve the observed field efficiency. Modeling results suggest significant energy savings relative to electric storage water heating systems (typical annual efficiencies around 0.90) providing for typical simple paybacks of six to ten years without any incentives. The economics versus gas water heating are currently much more challenging given the current low natural gas prices in much of the country. Increased market size for this technology would benefit cost effectiveness and spur greater technology innovation.
Hoeschele, M.; Weitzel, E.
Optimization Online - Lot sizing with inventory gains
Apr 27, 2006 ... Abstract: This paper introduces the single item lot sizing problem with inventory gains. This problem is a generalization of the classical single�...
Radiant Heating
Energy.gov (U.S. Department of Energy (DOE))
Radiant heating systems involve supplying heat directly to the floor or to panels in the walls or ceiling of a house. The systems depend largely on radiant heat transfer: the delivery of heat...
Investigations of novel heat pump systems for low carbon homes.
??The European standard EN15450 states that the Coefficient of Performance (COP) target range for a Ground Source Heat Pump (GSHP) installation should lie within the� (more)
Mempouo, B.
Heat Transfer Fluids for Solar Water Heating Systems | Department of Energy
Heat Transfer Fluids for Solar Water Heating Systems Heat Transfer Fluids for Solar Water Heating Systems Heat Transfer Fluids for Solar Water Heating Systems May 16, 2013 - 3:02pm Addthis Illustration of a solar water heater. Illustration of a solar water heater. Heat-transfer fluids carry heat through solar collectors and a heat exchanger to the heat storage tanks in solar water heating systems. When selecting a heat-transfer fluid, you and your solar heating contractor should consider the following criteria: Coefficient of expansion - the fractional change in length (or sometimes in volume, when specified) of a material for a unit change in temperature Viscosity - resistance of a liquid to sheer forces (and hence to flow) Thermal capacity - the ability of matter to store heat Freezing point - the temperature below which a liquid turns into a
Transport Coefficients of Gluon Plasma
Transport coefficients of gluon plasma are calculated for a SU(3) pure gauge model by lattice QCD simulations on $16^3 \\times 8$ and $24^3 \\times 8$ lattices. Simulations are carried out at a slightly above the deconfinement transition temperature $T_c$, where a new state of matter is currently being pursued in RHIC experiments. Our results show that the ratio of the shear viscosity to the entropy is less than one and the bulk viscosity is consistent with zero in the region, $1.4 \\leq T/T_c \\leq 1.8 $.
Atsushi Nakamura; Sunao Sakai
Design details of a compact heat exchanger and supporting hardware for heat recuperation in a high-temperature electrolysis application are presented. The recuperative heat exchanger uses a vacuum-brazed plate-fin design and operates between 300 and 800�C. It includes corrugated inserts for enhancement of heat transfer coefficients and extended heat transfer surface area. Two recuperative heat exchangers are required per each four-stack electrolysis module. The heat exchangers are mated to a base manifold unit that distributes the inlet and outlet flows to and from the four electrolysis stacks. Results of heat exchanger design calculations and assembly details are also presented.
G. K. Housley; J.E. O'Brien; G.L. Hawkes
Modularization and simulation techniques for heat balance-based energy and load calculation programs: the experience
Through sponsorship of the Loads Toolkit and coming changes to the Handbook of Fundamentals, ASHRAE has taken the lead in promoting a heat balance based approach as the "preferred " method for thermal load and energy analysis calculations. Building on previous ASHRAE research and to some extent the BLAST (Building Loads Analysis and System Thermodynamics) program, one of the goals of the Loads Toolkit research project is to obtain a heat balance based load calculation procedure that is relatively simple in structure where various algorithms, such as different exterior convection coefficient calculation techniques among many others, can be hooked into the heat balance without any restructuring. One of the keys to achieving this goal is the adaptation of legacy versions of a heat balance based approach a nd their modularization using a modern programming language such as FORTRAN90. This process was not a trivial task, and the insight gained in this re-engineering process in a small-scale (single zone) environment provided ideas for modularizing a larger-scale (multiple zone) program such as EnergyPlus. This paper gives an overview of the challenges faced in modularizing the heat balance algorithms in both the Loads Toolkit and EnergyPlus. In addition, it provides an analysis of the resulting heat balance routines in each project and suggestions for the developers of other simulation programs as well as those interested in working with the Loads Toolkit and EnergyPlus.
Richard K. Strand
On Thermally Forced Circulations over Heated Terrain
A combination of analytical and numerical models is used to gain insight into the dynamics of thermally forced circulations over diurnally heated terrain. Solutions are obtained for two-layer flows (representing the boundary layer and the ...
Daniel J. Kirshbaum
Radon emanation coefficients for phosphogysum
Phosphogypsum is a by-product of the phosphate fertilizer industry which is stockpiled in large quantities world-wide. Phosphogypsum consists mainly of dihydrate gypsum (CaSO{sub 4}2H{sub 2}O) but also contains elevated concentrations of {sup 226}Ra and other inorganic species which originate from the processing of phosphate rock. {sup 222}Rn gas is the first decay product of {sup 226}Ra and has been identified as one of the major environmental concerns associated with phosphogypsum. This study was conducted to determine effects of particle size, weathering, and moisture content on the {sup 222}Rn emanation coefficient ({epsilon}) for phosphogypsums. Practical conclusions from this study are discussed, such as the effects of a repository of a phosphogypsum site on radon emanation. 35 refs., 3 figs., 2 tabs.
Rutherford, P.M.; Dudas, M.J. [Univ. of Alberta, Edmonton (Canada); Arocena, J.M. [Univ. of Alberta, Edmonton (Canada)]|[Univ. of Northern British Columbia (Canada)
Applications of the Strong Heat Transformation by Pulse Flow in the Shell and Tube Heat Exchanger
This article deals with the heat exchange coefficient varied with pulse frequency in the pulsation tube with different flow forms. The findings show that heat can be exchanged coefficient with the pulse frequency, and it has an optimal frequency. The laminar flow and turbulent flow have approximately the same optimal frequency, i.e., about 8 Hz. When the pulsation source was placed in the upstream and downstream position, the heat transformation was completed dissimilarly. These results are coincident with previous experiments. The article also gives some information on the applications of the heat transformation by pulse flow in the shell and tube heat exchanger.
Chen, Y.; Zhao, J.
Rheology and Convective Heat Transfer of Colloidal Gas Aphrons in Horizontal Minichannels
Single-phase convective heat transfer in microchannels: aand Newell, M. E. , 1967. Heat transfer in fully developed3 /s at 130 W. Water CGA Heat Transfer Coefficient, h (W/m 2
Tseng, H.; Pilon, L.; Warrier, G.
Students gain work experience at WIPP
Students Gain Work Experience at WIPP Students Gain Work Experience at WIPP CARLSBAD, N.M., January 10, 2000 -- Students from two Eddy County high schools are gaining valuable experience by spending time with employees of the Westinghouse Waste Isolation Division and Day & Zimmermann, LLC at the Waste Isolation Pilot Plant (WIPP). Six students from Carlsbad High School and four students from Loving High School are participating in the 1999-2000 WIPP Shadow Program. A "shadow" is a student who teams up with an employee to gain hands-on experience in the workplace. This activity helps the students identify career options and develop confidence. Each student spends three days during the school year with a volunteer mentor at the work location. "This program offers our employees the opportunity to share their knowledge and
RESFEN 3.0: Program Description - a PC program for calculating the heating and cooling energy use of windows in residential buildings
Today`s energy-efficient windows can dramatically lower the heating and cooling costs associated with windows while increasing occupant comfort and minimizing window surface condensation problems. However, consumers are often confused about how to pick the most efficient window for their residence. They are typically given window properties such as U-factors or R-values, Solar Heat Gain Coefficients or Shading Coefficients, and air leakage rates. However, the relative importance of these properties depends on the site and building specific conditions. Furthermore, these properties are based on static evaluation conditions that are very different from the real situation the window will be used in. Knowing the energy and associated cost implications of different windows will help consumers and builders make the best decision for their particular application, whether it is a new home, an addition, or a window replacement. A computer tool such as RESFEN can help consumers and builders pick the most energy-efficient and cost-effective window for a given application. It calculates the heating and cooling energy use and associated costs as well as the peak heating and cooling demand for specific window products. Users define a problem by specifying the house type (single story or two story), geographic location, orientation, electricity and gas cost, and building configuration details (such as wall type, floor type, and HVAC systems). Window options are defined by specifying the window`s size, shading, and thermal properties: U-factor, Solar Heat Gain Coefficient, and air leakage rate. RESFEN calculates the energy and cost implications of the windows compared to insulated walls. The relative energy and cost impacts of two different windows can be compared against each other. RESFEN 3.0 is a major improvement over previous versions of RESFEN because it performs hourly calculations using a version of the DOE 2.1E energy analysis simulation program.
Huang, J.; Sullivan, R.; Arasteh, D.; Mitchell, R.
] K. C. Toh, X. Y. Chen, and J. C. Chai, "Numerical computation of fluid flow and heat transfer journal and conference papers. His current research interests include heat transfer and fluid-flow to substantially increase the heat transfer coefficient when a fluid is passing through microchannels. Heat sinks
Heating Alloys
...are used in many varied applications--from small household appliances to large industrial process heating systems and furnaces. In appliances or industrial process heating, the heating elements are usually either open
Heating Systems
A variety of heating technologies are available today. In addition to heat pumps, which are discussed separately, many homes and buildings use the following approaches:
Method and apparatus for fuel gas moisturization and heating
Fuel gas is saturated with water heated with a heat recovery steam generator heat source. The heat source is preferably a water heating section downstream of the lower pressure evaporator to provide better temperature matching between the hot and cold heat exchange streams in that portion of the heat recovery steam generator. The increased gas mass flow due to the addition of moisture results in increased power output from the gas and steam turbines. Fuel gas saturation is followed by superheating the fuel, preferably with bottom cycle heat sources, resulting in a larger thermal efficiency gain compared to current fuel heating methods. There is a gain in power output compared to no fuel heating, even when heating the fuel to above the LP steam temperature.
Ranasinghe, Jatila (Niskayuna, NY); Smith, Raub Warfield (Ballston Lake, NY)
1.1 This method covers the determination of the coefficient of linear thermal expansion of concrete test specimens by determinations of length change due to temperature changes. Because the thermal coefficient of concrete varies with moisture condition, being a minimum when saturated or oven dry and a maximum at about 70 percent saturated, it is important to select the relevant moisture condition for the tests to be made. 2. Apparatus 2.1. The apparatus shall consist of: 2.1.1 Heating Bath- A water bath in which concrete specimens can be maintained at a temperature of 140 � 2 F (60 � 1.1 C) (Note 1) 2.1.2 Cooling Bath- A water bath in which
unknown authors
Intrinsic gain modulation and adaptive neural coding
In many cases, the computation of a neural system can be reduced to a receptive field, or a set of linear filters, and a thresholding function, or gain curve, which determines the firing probability; this is known as a linear/nonlinear model. In some forms of sensory adaptation, these linear filters and gain curve adjust very rapidly to changes in the variance of a randomly varying driving input. An apparently similar but previously unrelated issue is the observation of gain control by background noise in cortical neurons: the slope of the firing rate vs current (f-I) curve changes with the variance of background random input. Here, we show a direct correspondence between these two observations by relating variance-dependent changes in the gain of f-I curves to characteristics of the changing empirical linear/nonlinear model obtained by sampling. In the case that the underlying system is fixed, we derive relationships relating the change of the gain with respect to both mean and variance with the receptive fi...
Hong, Sungho; Fairhall, Adrienne
Mechanical Compression Heat Pumps
Mechanical compression heat pumping is not new in industrial applications. In fact, industry history suggests that the theoretical concept was developed before 1825. Heat pump manufacturers gained the support of consultants and end-users when the energy crisis hit this country in 1973. That interest, today, has been dampened because there is a current abundance of the basic sources of industrial energy (namely oil and natural gas). Meanwhile, Mycom used the window of the current opportunities to develop, design and test compressors built to meet the needs of the mechanically demanding industrial heat pump applications which often require high compression ratios and temperatures in excess of 200 degrees F. This paper will review the theoretical foundation for heat pumps and present the mechanical and thermal requirements of the compressors which constitute the heart and soul of the system. It will also provide a quick survey of the available types of compressors for heat pumping and some of the industrial processes where simultaneous heating and cooling proceed along parallel demand paths. The case history will examine the system flexibility and the economic advantages realized in a barley malting process.
Apaloo, T. L.; Kawamura, K.; Matsuda, J.
Liquid-fluidized-bed heat exchanger design parameters
Liquid-fluidized-bed heat exchangers prevent scale accumulation on heat transfer surfaces and reduce the required heat transfer surface when scaling fluids, such as geothermal water, are used as the primary or working fluid. Liquid-fluidized-bed heat exchangers, principles of operation, and design parameters are described. Horizontal and vertical assemblies are discussed, including problems encountered with both designs. Bed-side heat transfer coefficients are given for limited cases, and a correlation is provided for calculating heat transfer coefficients for horizontal assemblies. A design example for a 60 kW/sub (e)/ (60 kW/sub (electric)/ preheater is included.
Allen, C.A.; Grimmett, E.S.
Gaining creative control over semiconductor nanowires
Gaining creative control over semiconductor nanowires Gaining creative control over semiconductor nanowires Gaining creative control over semiconductor nanowires Using a microfluidic reactor, Los Alamos researchers transformed the SLS process into a flow-based technique. September 26, 2013 Growth of nanowire precursors in a flowing carrier solvent Growth of nanowire precursors in a flowing carrier solvent The new "flow" solution-liquid-solid method allows scientists to slow down growth and thereby capture mechanistic details as the nanowires grow in solution. A Los Alamos research team has transformed the synthesis process of semiconductor nanowires for use in solar cells, batteries, electronics, sensors and photonics using a solution-liquid-solid (SLS) batch approach to achieve unprecedented control over growth rates, nanowire size and internal
Gaines Cavern Wind Project | Open Energy Information
Open Energy Info (EERE)
Cavern Wind Project Cavern Wind Project Jump to: navigation, search Name Gaines Cavern Wind Project Facility Gaines Cavern Wind Project Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner General Compression Developer Texas Dispatchable Wind 1 LLC Location Gaines County TX Coordinates 32.688556°, -103.062464° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":32.688556,"lon":-103.062464,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
GainSpan Corporation | Open Energy Information
GainSpan Corporation GainSpan Corporation Jump to: navigation, search Name GainSpan Corporation Address 121 Albright Way Place Los Gatos, California Zip 95032 Sector Efficiency Product Designs wireless sensor networks for a variety of applications including smart grid Website http://www.gainspan.com/ Coordinates 37.256998°, -121.964456° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.256998,"lon":-121.964456,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Intrinsically irreversible heat engine
A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. The second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium. In a preferred embodiment the engine comprises an acoustical drive and a housing containing a gas which is driven at a resonant frequency so as to be maintained in a standing wave. Operation of the engine at acoustic frequencies improves the power density and coefficient of performance. The second thermodynamic medium can be coupled to suitable heat exchangers to utilize the engine as a simple refrigeration device having no mechanical moving parts. Alternatively, the engine is reversible in function so as to be utilizable as a prime mover by coupling it to suitable sources and sinks of heat.
Wheatley, J.C.; Swift, G.W.; Migliori, A.
A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. the second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium. In a preferred embodiment the engine comprises an acoustical drive and a housing containing a gas which is driven at a resonant frequency so as to be maintained in a standing wave. Operation of the engine at acoustic frequencies improves the power density and coefficient of performance. The second thermodynamic medium can be coupled to suitable heat exchangers to utilize the engine as a simple refrigeration device having no mechanical moving parts. Alternatively, the engine is reversible in function so as to be utilizable as a prime mover by coupling it to suitable sources and sinks of heat.
Wheatley, John C. (Los Alamos, NM); Swift, Gregory W. (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)
A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. The second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium. In a preferred embodiment the engine comprises an acoustical drive and a housing containing a gas which is driven at a resonant frequency so as to be maintained in a standing wave. Operation of the engine at acoustic frequencies improves the power density and coefficient of performance. The second thermodynamic medium can be coupled to suitable heat exchangers to utilize the engine as a simple refrigeration device having no mechanical moving parts. Alternatively, the engine is reversible in function so as to be utilizable as a prime mover by coupling it to suitable sources and sinks of heat. 11 figs.
Reducing gain shifts in photomultiplier tubes
A means is provided for reducing gain shifts in multiplier tubes due to varying event count rates. It includes means for limiting the number of cascaded, active dynodes of the multiplier tube to a predetermined number with the last of predetermined number of dynodes being the output terminal of the tube. This output is applied to an amplifier to make up for the gain sacrificed by not totally utilizing all available active stages of the tube. Further reduction is obtained by illuminating the predetermined number of dynodes with a light source of such intensity that noise appearing at the output dynode associated with the illumination is negligible.
Cohn, Charles E. (Clarendon Hills, IL)
NIST: X-Ray Mass Attenuation Coefficients
... NIST reserves the right to charge for these data in the ... ?/? and the mass energy-absorption coefficient ... The tables cover energies of the photon (x-ray ...
Improved estimation of exterior film coefficient
Exterior convective coefficients were overestimated in the standard treatment (ASHRAE, DOE2) The result was an overestimate of savings potential for more efficient windows...
Modeling of Heat Transfer in Geothermal Heat Exchangers
Ground-coupled heat pump (GCHP) systems have been gaining increasing popularity for space conditioning in residential and commercial buildings. The geothermal heat exchanger (GHE) is devised for extraction or injection of thermal energy from/into the ground. This paper summarizes the authors' studies on heat transfer in ground-coupled heat pump systems. Taking the fluid axial convective heat transfer and thermal �short-circuiting� among U-tube legs into account, a quasi-3-D model has been solved for heat transfer inside boreholes. The transient 2-D temperature response in a semi-infinite medium with a line-source of finite length has also been derived for heat conduction outside boreholes. In order to investigate the impact of groundwater advection on the performance of ground heat exchangers, an analytical solution is obtained for a line heat source in an infinite porous medium with groundwater advection. These explicit expressions have more solid theoretical basis, and can be easily incorporated into computer programs for thermal analysis and engineering design of ground heat exchangers.
Cui, P.; Man, Y.; Fang, Z.
Heat exchanger with ceramic elements
An annular heat exchanger assembly includes a plurality of low thermal growth ceramic heat exchange members with inlet and exit flow ports on distinct faces. A mounting member locates each ceramic member in a near-annular array and seals the flow ports on the distinct faces into the separate flow paths of the heat exchanger. The mounting member adjusts for the temperature gradient in the assembly and the different coefficients of thermal expansion of the members of the assembly during all operating temperatures.
Corey, John A. (North Troy, NY)
PV ENERGY ROI Tracks Efficiency Gains
PV ENERGY ROI Tracks Efficiency Gains the state of PV today E nergy payback time (EPBT) is the time it takes for a photovoltaic (PV) system to produce all the energy used through- out its life cycle. A short EPBT corre- sponds to a high energy return on energy invest- ment
Gain International Work Experience in China
Gain International Work Experience in China www.StudyCLI.org "The CLI internship gave me a huge boost both personally and professionally. At 21 years old, I've lived in China and can speak basic city of Guilin, China. CLIinternsengageinadynamicrangeofprojects: Y Establishnewrelationshipswith
Virginia Tech
Collaborative Gain in Resource Sharing Communication Networks
We consider a Multi-Hopping communication network of users transmitting information on a shared medium with limited resources, e.g., limited time and limited bandwidth. Users are able to transmit, receive, retrieve and reply information in a collaborative way. We assume that two users collaborate (one acts as a relay for another) only if, as a result of the collaboration, they gain more capacity, save on resources or save power. We perform optimal resource allocation for three problems: 1) maximizing the capacity given limited resource and energy, 2) minimizing the resource usage given capacity and energy and 3) minimizing energy usage given capacity and resources. By comparing the collaboration gain as a function of the channels and available energies, one may decide either to collaborate or not and select a collaborator among candidates. We find the conditions in which acting as relay results in capacity gain, resource or power saving. We show that a significant gain is attained only if the channel energy g...
Akhavan-Astaneh, Saeed
Wind-Stress Coefficients at Light Winds
The increase of the wind-stress coefficient with wind velocity was found to start with winds as light as 3 m s?1, below which, following the formula for aerodynamically smooth flows, the wind-stress coefficient decreases as the wind velocity ...
APPENDIX J Partition Coefficients For Uranium
APPENDIX J Partition Coefficients For Uranium #12;Appendix J Partition Coefficients For Uranium J.1.0 Background The review of uranium Kd values obtained for a number of soils, crushed rock and their effects on uranium adsorption on soils are discussed below. The solution pH was also used as the basis
Diffusion coefficient of trona in water
Laboratory experiments were conducted to measure the diffusion coefficient of trona in water. The diffusion coefficient of trona from saturated solution in water was measured to be 1.167 *10/sup -5/ cm/sup 2//s with a standard devition of 6.2% at 25/degree/C.30 10/sup 9/ refs.
Mehta, G.D.; Jain, S.C.
Active and passive solar heating of buildings
An overview of both active and passive solar heating approaches for buildings is presented. Passive solar heating concepts--in which the thermal energy flow is by natural means--are described according to five classifications: direct gain, thermal storage wall, solar greenhouses, roof ponds, and convective loops. Results of simulation analyses are presented for a variety of climates. Active systems utilizing both liquid-heating collectors and air-heating collectors are described. Trends in the recent development of solar heating are discussed.
Balcomb, J.D.
U-030: Apache Tomcat Lets Untrusted Web Applications Gain Elevated...
0: Apache Tomcat Lets Untrusted Web Applications Gain Elevated Privileges U-030: Apache Tomcat Lets Untrusted Web Applications Gain Elevated Privileges November 9, 2011 - 8:30am...
Justification for change in AXAIR dispersion coefficients
AXAIR is the primary dose assessment code used at the Savannah River Site (SRS) to predict doses following hypothetical releases of relatively short durations. The atmospheric dispersion coefficients currently used in AXAIR are analytical expressions developed to fit the curves in the Turner Workbook as referred to in USNRC Regulatory Guide 1.145. This report explores the ramifications and benefits of changing the dispersion coefficients to a combination of Pasquill`s lateral dispersion coefficients and Briggs` vertical dispersion coefficients. The differences in the dispersion coefficients have a minor effect on the relative air concentrations for stability classes A--D, but a significant difference is seen for classes E, F, and G.
Simpkins, A.A.
Heat Conduction
Table 2 Differential equations for heat conduction in solids...conduction in solids General form with variable thermal properties General form with constant thermal properties General form, constant properties, without heat
Industrial and Commercial Heat Pump Applications in the United States
The energy crisis of 1973 accelerated the development of large-scale heat pumps in the United States. Since that time, the commercial, institutional, and industrial applications of heat pumps for waste heat recovery have expanded. This paper reviews the trends in heat pump cycle developments and discusses both the closed vapor compression cycle and refrigerants most commonly used and the open-cycle mechanical vapor compression heat pumps. Waste heat sources, heat loads served by heat pumps--and typical applications using heat pumps for large-scale space heating, domestic water heating, and industrial process water heating-- are discussed. Typical installations include commercial applications in hotels, high-rise apartments and condominiums, and office buildings. Institutional installations discussed include hospitals, universities, wastewater treatment plants, and airport terminals. Industrial applications largely center on food processing industries, feedwater heating, metal fabricating, and other industries. Reference is also made to other applications and alternative energy sources now gaining acceptance, including groundwater/geothermal water.
Niess, R. C.
by a cooling capacity, which is delivered in those rooms by heat exchangers where a heat transfer fluid - 2 and Fluid Science, 1-3:17. Mortada S., 2010. "Heat transfer performance of a mini-channel evaporator are mini-channel heat exchangers (MCHE) combining high heat transfer coefficients and low refrigerant
Heat exchanger
A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.
Daman, Ernest L. (Westfield, NJ); McCallister, Robert A. (Mountain Lakes, NJ)
Evaluation of solar gain through skylights for inclusion in the SP53 residential building loads data base
The energy performance of skylights is similar to that of windows in admitting solar heat gain, while at the same time providing a pathway for convective and conductive heat transfer through the building envelope. Since skylights are typically installed at angles ranging from 0{degrees} to 45{degrees}, and differ from windows in both their construction and operation, their conductive and convective heat gains or losses, as well as solar heat gain, will differ for the same rough opening and thermal characteristics. The objective of this work is to quantify the impact of solar gain through skylights on building heating and cooling loads in 45 climates, and to develop a method for including these data into the SP53 residential loads data base previously developed by LBL in support of DOE`s Automated Residential Energy Standard (ARES) program. The authors used the DOE-2.1C program to simulate the heating and cooling loads of a prototypical residential building while varying the size and solar characteristics of skylights and windows. The results are presented as Skylight Solar Loads, which are the contribution of solar gains through skylights to the overall building heating and cooling loads, and as Skylight Solar Load Ratios, which are the ratios of skylight solar loads to those for windows with the same orientation. The study shows that skylight solar loads are larger than those for windows in both heating and cooling. Skylight solar cooling loads are from three to four times greater than those for windows regardless of the skylight tilt, except for those facing north. These cooling loads are largest for south-facing skylights at a tilt angle of approximately 20{degrees}, and drop off at higher tilts and other orientations.
Hanford, J.W.; Huang, Y.J.
Gaines, Michigan: Energy Resources | Open Energy Information
Gaines, Michigan: Energy Resources Gaines, Michigan: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 42.8725303°, -83.9141254° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.8725303,"lon":-83.9141254,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Multiuser Diversity Gain in Cognitive Networks
Dynamic allocation of resources to the \\emph{best} link in large multiuser networks offers considerable improvement in spectral efficiency. This gain, often referred to as \\emph{multiuser diversity gain}, can be cast as double-logarithmic growth of the network throughput with the number of users. In this paper we consider large cognitive networks granted concurrent spectrum access with license-holding users. The primary network affords to share its under-utilized spectrum bands with the secondary users. We assess the optimal multiuser diversity gain in the cognitive networks by quantifying how the sum-rate throughput of the network scales with the number of secondary users. For this purpose we look at the optimal pairing of spectrum bands and secondary users, which is supervised by a central entity fully aware of the instantaneous channel conditions, and show that the throughput of the cognitive network scales double-logarithmically with the number of secondary users ($N$) and linearly with the number of avai...
Tajer, Ali
Separate effects of surface roughness, wettability and porosity on boiling heat transfer and critical heat flux and optimization of boiling surfaces
The separate effects of surface wettability, porosity, and roughness on critical heat flux (CHF) and heat transfer coefficient (HTC) were examined using carefully-engineered surfaces. All test surfaces were prepared on ...
O'Hanley, Harrison Fagan
Potential Efficiency Gains, and Energy and Carbon Emission Savings ...
Table 3. Potential Efficiency Gains, and Energy and Carbon Emission Savings, of Replacing Existing 1997 Appliances
Total Space Heating Water Heating Cook-
Gasoline and Diesel Fuel Update (EIA)
Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ... 222 194 17...
Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings ... 2,100...
Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ... 1,928 1,316...
Susanville District Heating District Heating Low Temperature...
Susanville District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Susanville District Heating District Heating Low Temperature...
Energy Consumption Survey: Energy End-Use Consumption Tables Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All...
Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ... 1,870 1,276...
Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ... 1,602 1,397...
Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings ... 2,037...
Microscale flow visualization of nucleate boiling in small channels: Mechanisms influencing heat transfer
This paper describes the use of a new test apparatus employing flow visualization via ultra-high-speed video and microscope optics to study microscale nucleate boiling in a small, rectangular, heated channel. The results presented are for water. Because of confinement effects produced by the channel cross section being of the same nominal size as the individual vapor bubbles nucleating at discrete wall sites, flow regimes and heat transfer mechanisms that occur in small channels are shown to be considerably different than those in large channels. Flow visualization data are presented depicting discrete bubble/bubble and bubble/wall interactions for moderate and high heat flux. Quantitative data are also presented on nucleate bubble growth behavior for a single nucleation site in the form of growth rates, bubble sizes, and frequency of generation in the presence and absence of a thin wall liquid layer. Mechanistic boiling behavior and trends are observed which support the use of this type of research as a powerful means to gain fundamental insights into why, under some conditions, nucleate boiling heat transfer coefficients are considerably larger in small channels than in large channels.
Kasza, K.E.; Didascalou, T.; Wambsganss, M.W.
Inversion of Robin coefficient by a spectral stochastic finite element approach
This paper investigates a variational approach to the nonlinear stochastic inverse problem of probabilistically calibrating the Robin coefficient from boundary measurements for the steady-state heat conduction. The problem is formulated into an optimization ... Keywords: Conjugate gradient method, Robin inverse problem, Spectral stochastic finite element method, Stochastic inverse problems, Uncertainty quantification
Bangti Jin; Jun Zou
Optimal control of the heat equation in an inhomogeneous body
In this paper we consider a heat flow in an inhomogeneous body without internal source. There exists special initial and boundary conditions in this system and we intend to find a convenient coefficient of heat conduction for this body so that body cool ... Keywords: approximation theory, heat equation, linear programming, measure theory
A. H. Borzabadi; A. V. Kamyad; M. H. Farahi
Air source heat pump system for drying application
This paper investigates the performance of an air source heat pump for drying purpose. In order to evaluate the performance analysis; a simulation study has been done. The results of simulation of heat pump dryer for different evaporator temperatures ... Keywords: air source heat pump, coefficient of performance (COP), condenser temperature and compressor work, dryer, evaporator temperature
R. Daghigh; M. H. Ruslan; A. Zaharim; K. Sopian
Heat transfer of finned tube bundles in crossflow
This volume correlates findings on heat transfer and hydraulic drag of bundles of finned tubes in crossflow at Reynolds numbers from 10/sup 4/ to 10/sup 6/. These studies illustrate fin, local, and mean heat transfer coefficients; effects of geometric parameters of the fins; effect of tube location within the bundle on heat transfer and hydraulic drag; and resistance of finned tube bundles.
Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.
Symmetry energy coefficients for asymmetric nuclear matter
Symmetry energy coefficients of asymmetric nuclear matter are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions for the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizability is investigated corresponding to the inverse symmetry energy coefficient which assumes different values at different asymmetries (and densities and temperatures). The symmetry energy coefficient (in the isovector channel) is found to increase as n-p asymmetries increase. The spin symmetry energy coefficient is also briefly investigated.
F�bio L. Braghin
Calculated �ngstr�im's Turbidity Coefficients for Fairbanks, Alaska
�ngstr�im's turbidity coefficient, ?, was determined from measurements of direct normal solar irradiance (broadband) at Fairbanks, Alaska (latitude, 64.82). The frequency distribution and seasonal changes of derived values were similar to those ...
John D. Fox
Determining Velocities and Mixing Coefficients from Tracers
The effort to determine oceanic velocities from tracer distributions relies on a knowledge of the effects of mixing. However, the macroscopic diffusion coefficient, K, is generally not known and must be calculated along with the velocity. The ...
Jae Hak Lee; George Veronis
Compensated gain control circuit for buck regulator command charge circuit
A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit.
Barrett, David M. (Albuquerque, NM)
Heat Kernel Short-Time Expansion within the Scope of Feynman-Kac Formula
The paper gives an outlook of the stochastic approach to derivation of heat kernel short-time asymptotic expansion and to effective evaluation of corresponding coefficients.
Stepin, S. A.; Rejrat, A. J. [Institute of Mathematics, University of Bialystok, Akademicka 2, 15-267 Bialystok (Poland)
Boiling heat transfer in a hydrofoil-based micro pin fin heat sink
-flow boiling over circular tube bundles has been meticulously studied; collected data and correlations for circular tube bundles. For exam- ple, Jensen and Hsu [81] conducted a parametric study of boiling heat transfer in a horizontal tube bundle and reported an increase in local heat transfer coefficient
Peles, Yoav
Experimental performance of solid-gas chemical heat pump in solar chemical heat pump dryer
A solar assisted chemical heat pump dryer has been designed, fabricated and tested. The performance of the system has been studied under the meteorological conditions of Malaysia. The system consists of four mean components: solar collector (evacuated ... Keywords: coefficient of performance, drying, energy density, evacuated tubes solar collector, reactor temperature, solid gas chemical heat pump
M. Ibrahim; K. Sopian; A. S. Hussein; W. R. W. Daud; A. Zaharim
German central solar heating plants with seasonal heat storage
Central solar heating plants contribute to the reduction of CO{sub 2}-emissions and global warming. The combination of central solar heating plants with seasonal heat storage enables high solar fractions of 50% and more. Several pilot central solar heating plants with seasonal heat storage (CSHPSS) built in Germany since 1996 have proven the appropriate operation of these systems and confirmed the high solar fractions. Four different types of seasonal thermal energy stores have been developed, tested and monitored under realistic operation conditions: Hot-water thermal energy store (e.g. in Friedrichshafen), gravel-water thermal energy store (e.g. in Steinfurt-Borghorst), borehole thermal energy store (in Neckarsulm) and aquifer thermal energy store (in Rostock). In this paper, measured heat balances of several German CSHPSS are presented. The different types of thermal energy stores and the affiliated central solar heating plants and district heating systems are described. Their operational characteristics are compared using measured data gained from an extensive monitoring program. Thus long-term operational experiences such as the influence of net return temperatures are shown. (author)
Bauer, D.; Marx, R.; Nussbicker-Lux, J.; Ochs, F.; Heidemann, W. [Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Pfaffenwaldring 6, D-70550 Stuttgart (Germany); Mueller-Steinhagen, H. [Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Pfaffenwaldring 6, D-70550 Stuttgart (Germany); Institute of Technical Thermodynamics (ITT), German Aerospace Centre (DLR), Stuttgart (Germany)
Passive solar heating of buildings
Passive solar heating concepts--in which the thermal energy flow is by natural means--are described according to five general classifications: direct gain, thermal storage wall, solar greenhouses, roof ponds, and convective loops. Examples of each are discussed. Passive test rooms built at Los Alamos are described and results are presented. Mathematical simulation techniques based on thermal network analysis are given together with validation comparisons against test room data. Systems analysis results for 29 climates are presented showing that the concepts should have wide applicability for solar heating.
Balcomb, J.D.; Hedstrom, J.C.; McFarland, R.D.
Risk Insights Gained from Fire Incidents
There now exist close to 20 years of history in the application of Probabilistic Risk Assessment (PRA) for the analysis of fire risk at nuclear power plants. The current methods are based on various assumptions regarding fire phenomena, the impact of fire on equipment and operator response, and the overall progression of a fire event from initiation through final resolution. Over this same time period, a number of significant fire incidents have occurred at nuclear power plants around the world. Insights gained from US experience have been used in US studies as the statistical basis for establishing fire initiation frequencies both as a function of the plant area and the initiating fire source.To a lesser extent, the fire experience has also been used to assess the general severity and duration of fires. However, aside from these statistical analyses, the incidents have rarely been scrutinized in detail to verify the underlying assumptions of fire PRAs. This paper discusses an effort, under which a set of fire incidents are being reviewed in order to gain insights directly relevant to the methods, data, and assumptions that form the basis for current fire PRAs. The paper focuses on the objectives of the effort, the specific fire events being reviews methodology, and anticipated follow-on activities.
Kazarians, Mardy; Nowlen, Steven P.
Efficiency of unitary heat pumps
The efficiencies of approximately 500 unitary heat pumps, from 30 different manufacturers, certified by the Air Conditioning and Refrigeration Institute (ARI) were examined. The certified units account for about 90% of all unitary heat pumps manufactured in the U.S. with a rated cooling capacity below 135,000 Btu/hr, and thus represent a comprehensive data file of the efficiencies of unitary heat pumps offered for sale in the U.S. A computer was used to group the heat pumps according to type and capacity, and to calculate their coefficients of performance (COP) using the data contained in ARI current Directory (April 1 to July 31, 1973) of Certified Unitary Heat Pumps. The results show that the COP of the heat pumps varied from a low of 1.5 to a high of 3.15 or a factor of 2 between the lowest and the highest efficiency, and that the average COP was 2.1 in cooling and 2.4 in heating. The variations of COP with heat pump size, type, manufacturer and outdoor temperature are presented.
Nwude, J.K.; Roman, A.J.
Heat transfer. [heat transfer roller employing a heat pipe
A heat transfer roller embodying a heat pipe is disclosed. The heat pipe is mounted on a shaft, and the shaft is adapted for rotation on its axis.
Sarcia, D.S.
Heat reclaimer
A device for reclaiming heat from stove pipes and the like. A semi-circular shaped hollow enclosed housing with a highly thermal-conductive concave surface is mounted contactingly to surround approximately one-half of the circumference of the stove pipe. The concave surface is formed to contact the pipe at a maximum number of points along that surface. The hollow interior of the housing contains thin multi-surfaced projections which are integral with the concave surface and conductively transfer heat from the stove pipe and concave surface to heat the air in the housing. A fan blower is attached via an air conduit to an entrance opening in the housing. When turned on, the blower pushes the heated interior air out a plurality of air exit openings in the ends of the housing and brings in lower temperature outside air for heating.
Parham, F.
Heat Stroke
stress, from exertion or hot environments, places stress, from exertion or hot environments, places workers at risk for illnesses such as heat stroke, heat exhaustion, or heat cramps. Heat Stroke A condition that occurs when the body becomes unable to control its temperature, and can cause death or permanent disability. Symptoms ■ High body temperature ■ Confusion ■ Loss of coordination ■ Hot, dry skin or profuse sweating ■ Throbbing headache ■ Seizures, coma First Aid ■ Request immediate medical assistance. ■ Move the worker to a cool, shaded area. ■ Remove excess clothing and apply cool water to their body. Heat Exhaustion The body's response to an excessive loss of water and salt, usually through sweating. Symptoms ■ Rapid heart beat ■ Heavy sweating ■ Extreme weakness or fatigue ■
Heat transfer in freeboard region of fluidized beds
This research involved the study of heat transfer and fluid mechanic characteristics around a horizontal tube in the freeboard region of fluidized beds. Heat transfer coefficients were experimetnally measured for different bed temperatures, particle sizes, gas flow rates, and tube elevations in the freeboard region of air fluidized beds at atmospheric pressure. Local heat transfer coefficients were found to vary significantly with angular position around the tube. Average heat transfer coefficients were found to decrease with increasing freeboard tube elevation and approach the values for gas convection plus radiation for any given gas velocity. For a fixed tube elevation, heat transfer coefficients generally increased with increasing gas velocity and with high particle entrainment they can approach the magnitudes found for immersed tubes. Heat transfer coefficients were also found to increase with increasing bed temperature. It was concluded that this increase is partly due to increase of radiative heat transfer and partly due to change of thermal properties of the fluidizing gas and particles. To investigate the fluid mechanic behavior of gas and particles around a freeboard tube, transient particle tube contacts were measured with a special capacitance probe in room temperature experiments. The results indicated that the tube surface experiences alternating dense and lean phase contacts. Quantitative information for local characteristics was obtained from the capacitance signals and used to develop a phenomenological model for prediction of the heat transfer coefficients around freeboard tubes. The packet renewal theory was modified to account for the dense phase heat transfer and a new model was suggested for the lean phase heat transfer. Finally, an empirical freeboard heat transfer correlation was developed from functional analysis of the freeboard heat transfer data using nondimensional groups representing gas velocity and tube elevation.
Biyikli, S.; Tuzla, K.; Chen, J.C.
Evaluating the Moisture Conditions in the Fractured Rock at Yucca Mountain: The Impact of Natural Convection Processes in Heated Emplacement Drifts
multiphase flow and heat-transfer processes. Pore-waterprocesses, and various empirical correlations have been developed for heat and mass transferprocess, with effective dispersion coefficients estimated from supporting CFD analyses. Mass and heat transfer
Birkholzer, J.T.; Webb, S.W.; Halecky, N.; Peterson, P.F.; Bodvarsson, G.S.
Coal home heating and environmental tobacco smoke in relation to lower respiratory illness in Czech children, from birth to 3 years of age
The coefficient for wood as a heating source was elevated,distant heating) Natural gas Electricity Coal Wood Unknown/distant heating and use of natural gas, electricity, or wood
Financing Renewable Energy - No Pain, No Gain
newresourcebank.com newresourcebank.com Financing Renewable Energy "No Pain, No Gain" New Resource Bank: A Radical Idea Our mission is to promote sustainable living in our community with everything we do. Where Does Your Money Spend The Night? 9/4/2012 2 Renewable Energy Projects Anaerobic Manure Digester This anaerobic manure digester improves manure management and sustainability for partner dairies while generating renewable electricity for sale to a local public utility. Anaerobic digestion is a natural process that converts a portion of the organic carbon in manure (and other waste streams) into methane and carbon dioxide. o Production of renewable energy (Biogas) o Carbon offsets o Reduction of greenhouse gas emissions o Potential pathogen reduction in manure
Financing Renewable Energy - No Pain, No Gain | Department of...
Financing Renewable Energy - No Pain, No Gain Financing Renewable Energy - No Pain, No Gain U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE)...
Advanced Chemical Heat Pumps Using Liquid-Vapor Reactions
Chemical heat pumps utilizing liquid-vapor reactions can be configured in forms analogous to electric drive vapor-compression heat pumps and heat activated absorption heat pumps. Basic thermodynamic considerations eliminate some heat pumps and place restrictive working fluid requirements on others, but two thermodynamically feasible systems have significant potential advantage over conventional technology. An electric drive reactive heat pump can use smaller heat exchangers and compressor than a vapor-compression machine, and have more flexible operating characteristics. A waste heat driven heat pump (temperature amplifier) using liquid-vapor chemical reactions- can operate with higher coefficient of performance and smaller heat exchangers than an absorption temperature amplifying heat pump. Higher temperatures and larger temperature lifts should also be possible.
Kirol, L.
Correlation between thermal expansion and heat capacity
Theoretically predicted linear correlation between the volume coefficient of thermal expansion and the thermal heat capacity was investigated for highly symmetrical atomic arrangements. Normalizing the data of these thermodynamic parameters to the Debye temperature gives practically identical curves from zero Kelvin to the Debye temperature. This result is consistent with the predicted linear correlation. At temperatures higher than the Debye temperature the normalized values of the thermal expansion are always higher than the normalized value of the heat capacity. The detected correlation has significant computational advantage since it allows calculating the volume coefficient of thermal expansion from one experimental data by using the Debye function.
Jozsef Garai
New Baldrige Book Helps Organizations Gain 20/20 Foresight
New Baldrige Book Helps Organizations Gain 20/20 Foresight. From NIST Tech Beat: September 27, 2011. ...
Geothermal Energy: Residential Space Heating
The purpose of this study, which was carried out under the auspices of the DGRST, was to determine the best way to use geothermal hot water for residential space heating. It quickly became apparent that the type of heating apparatus used in the housing units was most important and that heat pumps could be a valuable asset, making it possible to extract even more geothermal heat and thus substantially improve the cost benefit of the systems. Many factors play a significant role in this problem. Therefore, after a first stage devoted to analyzing the problem through a manual method which proved quite useful, the systematic consideration of all important aspects led us to use a computer to optimize solutions and process a large number of cases. The software used for this general study can also be used to work out particular cases: it is now available to any interested party through DGRST. This program makes it possible to: (1) take climatic conditions into account in a very detailed manner, including temperatures as well as insolation. 864 cases corresponding to 36 typical days divided into 24 hours each were chosen to represent the heating season. They make it possible to define the heating needs of any type of housing unit. (2) simulate and analyze the behavior in practice of a geothermal heating system when heat is extracted from the well by a simple heat exchanger. This simulation makes it possible to evaluate the respective qualities of various types of heating apparatus which can be used in homes. It also makes it possible to define the best control systems for the central system and substations and to assess quite accurately the presence of terminal controls, such as radiators with thermostatically controlled valves. (3) determine to what extent the addition of a heat pump makes it possible to improve the cost benefit of geothermal heating. When its average characteristics and heating use conditions (price, coefficient of performance, length of utilization, electrical rates, etc.) are taken into account, the heat pump should not be scaled for maximum heating power. Consequently, the program considers several possible sizes, with different installation schemes, and selects for each case the value which corresponds to the lowest cost of heating.
Energy Basics: Heat Pump Systems
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Systems Air-Source Heat Pumps Ductless Mini-Split Heat Pumps Absorption Heat Pumps Geothermal Heat Pumps Supporting Equipment for Heating & Cooling Systems Water Heating Heat...
Heat collector
A heat collector and method suitable for efficiently and cheaply collecting solar and other thermal energy are provided. The collector employs a heat pipe in a gravity-assist mode and is not evacuated. The collector has many advantages, some of which include ease of assembly, reduced structural stresses on the heat pipe enclosure, and a low total materials cost requirement. Natural convective forces drive the collector, which after startup operates entirely passively due in part to differences in molecular weights of gaseous components within the collector.
Merrigan, M.A.
Merrigan, Michael A. (Santa Cruz, NM)
Determination of Longitudinal Dispersion Coefficient and Net
, New York, New York 10027 Physical processes such as advection, dispersion, and air-water gas exchange of the gas tracer, u is the average cross-sectional current velocity, Kx is the longitudinal dispersion in the Hudson River. Similar to the difference in longitudinal dispersion coefficients, the difference in gas
Ho, David
Differential coefficients of orthogonal matrix polynomials
We find explicit formulas for raising and lowering first order differential operators for orthogonal matrix polynomials. We derive recurrence relations for the coefficients in the raising and lowering operators. Some examples are given. Keywords: Annihilation operators, Creation operators, Orthogonal matrix polynomials, primary 33E30, secondary 42C05
Antonio J. Duran; Mourad E. H. Ismail
Study on Hybrid Solar Energy and Ground-Source Heat Pump System
Aim at the weakness of more influenced by the environment etc. factor and the heat flow density lower when the solar energy was make use of heating, so the design method of the hybrid solar energy and ground-source heat pump is proposed, and the operating ... Keywords: solar energy, ground-source, heat pump, coefficient of performance
Liu Yi; Li Bing-xi; Zhou Yi; Fu Zhong-bin; Xu Xin-hai
Corrosive resistant heat exchanger
A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.
Richlen, Scott L. (Annandale, VA)
An apparatus for reclaiming heat from the discharge gas from a combustion fuel heating unit, which has: inlet and outlet sections; an expansion section whose circumference gradually increases in the direction of flow, thereby providing an increased area for heat transfer; flow splitter plates which lie within and act in conjunction with the expansion section wall to form flow compartments, which flow splitter plates and expansion section wall have a slope, with respect to the centroidal axis of the flow compartment not exceeding 0.1228, which geometry prevents a separation of the flow from the enclosing walls, thereby increasing heat transfer and maintaining the drafting function; and a reduction section which converges the flow to the outlet section.
Horkey, E.J.
Hodges residence: performance of a direct gain passive solar home in Iowa
Results are presented for the performance of the Hodges Residence, a 2200-square-foot earth-sheltered direct gain passive solar home in Ames, Iowa, during the 1979-80 heating season, its first occupied season. No night insulation was used on its 500 square feet of double-pane glass. Total auxiliary heat required was 43 GJ (41 MBTU) gross and 26 GJ (25 MBTU) net, amounting, respectively, to 60 and 36 kJ/C/sup 0/-day-m/sup 2/ (2.9 and 1.8 BTU/F/sup 0/-day-ft/sup 2/). The heating season was unusually cloudy and included the cloudiest January in the 21 years of Ames insolation measurements. Results are also presented for the performance of the hollow-core floor which serves as the main storage mass and for the comfort range in the house.
Hodges, L.
A heat exchanger is designed for use in the transfer of heat between a radioactive fiuid and a non-radioactive fiuid. The exchanger employs a removable section containing the non-hazardous fluid extending into the section designed to contain the radioactive fluid. The removable section is provided with a construction to cancel out thermal stresses. The stationary section is pressurized to prevent leakage of the radioactive fiuid and to maintain a safe, desirable level for this fiuid. (AEC)
Fox, T.H. III; Richey, T. Jr.; Winders, G.R.
Process Heating
This technical update uses real world examples to discuss applications of electrotechnology in industrial process heating and to highlight some of the emerging technologies in this field. These emerging technologies, when implemented in a plant, will provide significant energy savings as well as increase productivity. The report presents three case studies of successful implementation of two different electric process-heating technologies in three different industries. The case studies show that in some ...
Electric top drives gain wide industry acceptance
Since its introduction, the top drive drilling system has gained acceptance as a productive and safe method for drilling oil and gas wells. Originally, the system was used mostly for offshore and higher cost land drilling, and it had to be installed as a permanent installation because of its enormous weight and size. Essentially, a top drive replaces the kelly and rotary table as the means of rotating drillpipe on oil, gas and geothermal rigs and is considered to be 15% to 40% more efficient than a kelly drive. Top drive systems allow the operator to drill and maintain directional orientation for triple stands and provide tripping efficiency because of the ability to ream and circulate with triple stands, to reduce the risk of stuck pipe or lost wells, and to improve well control and pipe handling safety. The paper describes electric top drives with DC motors, top drives with AC motors, top drives with permanent magnet motors, and top drives with permanent magnet brushless synchronous motors.
Riahi, M.L.
Heat Transfer between Graphene and Amorphous SiO2
We study the heat transfer between graphene and amorphous SiO2. We include both the heat transfer from the area of real contact, and between the surfaces in the non-contact region. We consider the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies, and the heat transfer by the gas in the non-contact region. We find that the dominant contribution to the heat transfer result from the area of real contact, and the calculated value of the heat transfer coefficient is in good agreement with the value deduced from experimental data.
B. N. J. Persson; H. Ueba
USDA Global Agricultural Information Network (GAIN) | Open Energy
USDA Global Agricultural Information Network (GAIN) USDA Global Agricultural Information Network (GAIN) Jump to: navigation, search Tool Summary Name: USDA Global Agricultural Information Network (GAIN) Agency/Company /Organization: United States Department of Agriculture Sector: Land Focus Area: Agriculture Topics: Co-benefits assessment, GHG inventory, Market analysis Resource Type: Dataset Website: gain.fas.usda.gov/Pages/Default.aspx USDA Global Agricultural Information Network (GAIN) Screenshot References: GAIN[1] Overview "USDA'S Global Agriculture Information Network (GAIN) provides timely information on the agricultural economy, products and issues in foreign countries since 1995 that are likely to have an impact on United States agricultural production and trade. U.S. Foreign Service officers working at
Environmental concerns gaining importance in industry operations
This paper reports that environmental concerns have leapt to the forefront of industry's concerns in operating in Latin America. The United Nations Conference on Environment and Development in Rio de Janeiro June 3-14 focused a strong world spotlight on the region's environmental and commercial resources. Protection of the region's rain forests, which accounts for a huge share of the world's total, is emerging as an especially contentious issue. Ecuador's Oriente region may well prove the litmus test of how or whether oil and gas companies are able to operate in Latin American rain forests. Controversy over industry operations in the Oriente have heated to the point that environmentalist and native groups have routinely picketed company offices in Quito and used mass fundraiser mailings in North America.
Not Available
Quenching of spontaneous emission coefficients in plasmas
We have observed changing Einstein coefficients of spontaneous emission as a function of electron density in CO/sub 2/ laser-produced plasmas. These measurements are based on the intensity branching ratio of CIV lines 5801 to 5812 A and 312.41 to 312.46 A which share a common upper level. Similar observations for CIII lines are also discussed. 12 refs., 3 figs.
Chung, Y.; Lemaire, P.; Suckewer, S.
DHC: a diurnal heat capacity program for microcomputers
A computer program has been developed that can predict the temperature swing in direct gain passive solar buildings. The diurnal heat capacity (DHC) program calculates the DHC for any combination of homogeneous or layered surfaces using closed-form harmonic solutions to the heat diffusion equation. The theory is described, a Basic program listing is provided, and an example solution printout is given.
A learning agent for heat-pump thermostat control
Heating, Ventilation and Air Conditioning (HVAC) systems are one of the biggest energy consumers around the world. With the efforts of moving to sustainable energy consumption, heat-pump based HVAC systems have gained popularity due to their high efficiency ... Keywords: control, energy savings, machine learning
Daniel Urieli, Peter Stone
Description and operation of Haakon School geothermal-heating system
To encourage the development of hydrothermal energy, twenty-three demonstration projects were funded. The Haakon School project is one of twelve such projects. The geothermal direct-use heating system at the Haakon School complex in Philip, South Dakota is described and information gained during approximately three heating seasons of operation is presented.
Childs, F.W.; Kirol, L.D.; Sanders, R.D.; McLatchy, M.J.
PIA - Northeast Home Heating Oil Reserve System (Heating Oil...
PIA - Northeast Home Heating Oil Reserve System (Heating Oil) PIA - Northeast Home Heating Oil Reserve System (Heating Oil) PIA - Northeast Home Heating Oil Reserve System (Heating...
Northeast Home Heating Oil Reserve System (Heating Oil) PIA - Northeast Home Heating Oil Reserve System (Heating Oil) PIA - Northeast Home Heating Oil Reserve System (Heating Oil)...
Heat is generated by the utilization of high energy neutrons produced as by nuclear reactions between hydrogen isotopes in a blanket zone containing lithium, a neutron moderator, and uranium and/or thorium effective to achieve multtplicatton of the high energy neutron. The rnultiplied and moderated neutrons produced react further with lithium-6 to produce tritium in the blanket. Thermal neutron fissionable materials are also produced and consumed in situ in the blanket zone. The heat produced by the aggregate of the various nuclear reactions is then withdrawn from the blanket zone to be used or otherwise disposed externally. (AEC)
Imhoff, D.H.; Harker, W.H.
Energy Basics: Absorption Heat Pumps
Systems Air-Source Heat Pumps Ductless Mini-Split Heat Pumps Absorption Heat Pumps Geothermal Heat Pumps Supporting Equipment for Heating & Cooling Systems Water Heating...
Energy Basics: Geothermal Heat Pumps
A heat exchanger of the straight tube type in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration.
Wolowodiuk, Walter (New Providence, NJ)
A heat reclaimer for the exhaust flue of a heating unit comprises a housing having an air input space, an air output space, and an exhaust space, with a plurality of tubes connected between and communicating the air input space with the air output space and extending through the exhaust space. The exhaust flue of the heating unit is connected into the exhaust space of the housing and an exhaust output is connected to the housing extending from the exhaust space for venting exhaust coming from the heater into the exhaust space to a chimney, for example. A float or level switch is connected to the housing near the bottom of the exhaust space for switching, for example, an alarm if water accumulates in the exhaust space from condensed water vapor in the exhaust. At least one hole is also provided in the housing above the level of the float switch to permit condensed water to leave the exhaust space. The hole is provided in case the float switch clogs with soot. A wiping device may also be provided in the exhaust space for wiping the exterior surfaces of the tubes and removing films of water and soot which might accumulate thereon and reduce their heat transfer capacity.
Bellaff, L.
Performance monitoring and replacement of heat exchanger components and materials
This book contains papers presented at the 1990 International Joint Power Generation Conference. Included are the following articles: A comparison of heat transfer coefficients, Extend heat exchanger and condenser life with metal alloy inserts, Design, service conditions and deaerator cracking in Dutch utility boilers.
Maurer, J.R. (Allegheny Ludlum Steel (US))
Variational formulations for resting irreversible fluids with heat flow
Nonequilibrium statistical mechanics helps to estimate corrections to the entropy and energy of the fluid with heat flux in terms of the nonequilibrium distribution function, f. This leads to the coefficients of wave model of heat: relaxation ... Keywords: conservation laws, entropy, grad solution, variational calculus, wave equations
Stanislaw Sieniutycz; Piotr Kuran
Survey of hybrid solar heat pump drying systems
Solar drying is in practice since the ancient time for preservation of food and agriculture crops. The objective of most drying processes is to reduce the moisture content of the product to a specified value. Solar dryers used in agriculture for food ... Keywords: coefficient of performance (COP), direct expansion SAHD, drying chamber, heat pump, solar assisted heat pumps dryer (SAHPD), solar fraction
R. Daghigh; K. Sopian; M. H. Ruslan; M. A. Alghoul; C. H. Lim; S. Mat; B. Ali; M. Yahya; A. Zaharim; M. Y. Sulaiman
Marcellus natural gas production gains affect spreads between ...
... issues, and trends. FAQs Glossary For ... Marcellus natural gas production gains affect spreads ... Supporting increased use of natural gas for power ...
Heat exchanger with transpired, highly porous fins
The heat exchanger includes a fin and tube assembly with increased heat transfer surface area positioned within a hollow chamber of a housing to provide effective heat transfer between a gas flowing within the hollow chamber and a fluid flowing in the fin and tube assembly. A fan is included to force a gas, such as air, to flow through the hollow chamber and through the fin and tube assembly. The fin and tube assembly comprises fluid conduits to direct the fluid through the heat exchanger, to prevent mixing with the gas, and to provide a heat transfer surface or pathway between the fluid and the gas. A heat transfer element is provided in the fin and tube assembly to provide extended heat transfer surfaces for the fluid conduits. The heat transfer element is corrugated to form fins between alternating ridges and grooves that define flow channels for directing the gas flow. The fins are fabricated from a thin, heat conductive material containing numerous orifices or pores for transpiring the gas out of the flow channel. The grooves are closed or only partially open so that all or substantially all of the gas is transpired through the fins so that heat is exchanged on the front and back surfaces of the fins and also within the interior of the orifices, thereby significantly increasing the available the heat transfer surface of the heat exchanger. The transpired fins also increase heat transfer effectiveness of the heat exchanger by increasing the heat transfer coefficient by disrupting boundary layer development on the fins and by establishing other beneficial gas flow patterns, all at desirable pressure drops.
Kutscher, Charles F. (Golden, CO); Gawlik, Keith (Boulder, CO)
Bounds on Transport Coefficients of Porous Media
An analytical formulation of conductivity bounds by Bergman and Milton is used in a different way to obtain rigorous bounds on the real transport coefficients (electrical conductivity, thermal conductivity, and/or fluid permeability) of a fluid-saturated porous medium. These bounds do not depend explicitly on the porosity, but rather on two formation factors--one associated with the pore space and the other with the solid frame. Hashin-Shtrikman bounds for transport in random polycrystals of porous-material laminates will also be discussed.
Berryman, J G
Reactive sticking coefficients of silane on silicon
Reactive sticking coefficients (RSCs) were measured for silane and disilane on polycrystalline silicon for a wide range of temperature and flux (pressure) conditions. The data were obtained from deposition rate measurements using molecular beam scattering and a very low pressure cold wall reactor. The RSCs have non-Arrhenius temperature dependences and decreases with increasing flux at low (710/sup 0/) temperatures. A simple model involving dissociative adsorption of silane is consistent with these results. The results are compared with previous studies of the SiH/sub 4//Si(s) reaction.
Buss, R.J.; Ho, P.; Breiland, W.G.; Coltrin, M.E.
Transmission eigenvalues for operators with constant coefficients
In this paper we study the interior transmission problem and transmission eigenvalues for multiplicative perturbations of linear partial differential operator of order $\\ge 2$ with constant real coefficients. Under suitable growth conditions on the symbol of the operator and the perturbation, we show the discreteness of the set of transmission eigenvalues and derive sufficient conditions on the existence of transmission eigenvalues. We apply these techniques to the case of the biharmonic operator and the Dirac system. In the hypoelliptic case we present a connection to scattering theory.
Michael Hitrik; Katsiaryna Krupchyk; Petri Ola; Lassi P�iv�rinta
Transport coefficients of a massive pion gas
We review or main results concerning the transport coefficients of a light meson gas, in particular we focus on the case of a massive pion gas. Leading order results according to the chiral power-counting are presented for the DC electrical conductivity, thermal conductivity, shear viscosity, and bulk viscosity. We also comment on the possible correlation between the bulk viscosity and the trace anomaly in QCD, as well as the relation between unitarity and a minimum of the quotient $\\eta/s$ near the phase transition.
D. Fernandez-Fraile; A. Gomez Nicola
A variety of methods of sealing supply-air registers wereand sealing practices when leakage at connections to duct-mounted equipment is not considered. The measured air-
intended to characterize sun-facing solar equipment, whosebe tilted toward the sun to reduce solar incidence angle.zenith sun (AM1) reasonably approximates the solar position
of In press at Progress in Solar Energy April 28, 2010 R.2008. In press at Progress in Solar Energy April 28, 2010 R.ectance measurements. Solar Energy Materials & Solar Cells,
Y. Chen, The effect of solar radiation on dynamic thermaldependant upon solar radiation, ASHRAE Transactions, (2006)M. Filippi, B.W. Olesen, Solar radiation and cooling load
of In press at Progress in Solar Energy April 28, 2010 R.and P. Berdahl Measuring solar re?ectance�Part I sunlight2008. In press at Progress in Solar Energy April 28, 2010 R.
Solar Heat Gain Through Fenestration Systems Containing Shading: Procedures for Estimating Performace from Minimal Data
Layer Calculation. � ASHRAE Trans. 100 (pt. 1): 1065-1072.Layer Calculation. � ASHRAE Trans. 100 (pt.1): 1073-1086.
Devices & Services Solar Spectrum Re?ectometer. Online ator version 6 of the Solar Spectrum Re?ectometer. Akbari�sthe Devices & Services Solar Spectrum Re?ectometer [18] is
Report CEC-400-2008-001-CMF, California Energy Commission,and pavements, and California�s 2008 Title 24 (Buildingand compliance with California Title 24, ASHRAE Standard
Dealing with Uncertainties During Heat Exchanger Design
Over the last thirty years much progress has been made in heat exchanger design methodology. Even so, the design engineer still has to deal with a great deal of uncertainty. Whilst the methods used to predict heat transfer coefficients are now quite sophisticated and take account of many physical factors, the results they yield are still inaccurate. Physical property information is required for the estimation of heat transfer coefficients. Available information is often of dubious accuracy. Even given accurate properties modern methods for the predictions of tube-side heat transfer coefficient can be expected to have an accuracy of only � 10%. For the shell-side, higher errors (say, around �15%) can be expected. Perhaps worst of all, comes the specification of fouling resistance (the allowance made for the thermal resistance presented by dirt layers deposited on the heat exchanger tubes). In most instances there is little science or understanding behind the specification of these resistances. Traditionally there have been two approaches to dealing with these uncertainties: over-specification of fouling resistance; and, addition of 'design margin' (i.e. addition of extra surface area). There are cases in which both approaches are adopted. The engineer specifying the required duty provides a higher than necessary fouling resistance whilst the exchanger designer adds design margin! Both approaches result in 'over-design'.
Polley, G. T.; Pugh, S. J.
WSEAS-HMT'08-Kostic, PAGE 1 of 2 HMT'08-The 5th WSEAS International Conference on HEAT and MASS TRANSFER
. It has been applied to measure heat transfer coefficients of water flowing in a round tube k/cPr pµ= (-) exp experimental q& heat flow rate by unit of volume (W.m -3 ) f fluid R radius (m) i, performed in the GRESPI laboratory of Reims, was to estimate heat transfer coefficients between the flowing
Kostic, Milivoje M.
Characterization of crushed glass as a transpired air heating solar collector material
The use of crushed glass matrices as the heat-absorbing media in air heating solar collectors is investigated. An experimantal program was undertaken to characterize the most likely candidate glass types and sizes by measuring pressure drops, optical extinction coefficients, and volumetric heat transfer coefficients. Bed efficiencies were also measured and found to be similar to those expected for screen matrices unless critical amounts of clear glass were used as a top layer, which results in lower efficiency.
Collier, R.K.
Liquid-fluidized-bed heat exchanger flow distribution models
Allied Chemical Corporation at the Idaho National Engineering Laboratory is developing liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications. Sand fluidized by geothermal water on the shell side prevents scaling and increases heat transfer coefficients over conventional heat exchangers. Tests were conducted on two instrumented fluidized-bed heat exchanger models, constructed primarily of plexiglass, which differ in tube bundle orientation. One contains a horizontal bundle and the other a vertical tube bundle. Plexiglass construction allowed visual observation of flow patterns. The vertical model proved to have more uniform flow distribution and higher heat transfer coefficients than the horizontal model. The horizontal heat exchanger experienced piling on top of the tubes and areas of poor fluidization existed in the bed. Geometric considerations show that a horizontal design is more conducive to large flow rates than a vertical design. New design concepts for both vertical and horizontal assemblies and recommendations for further developmental work are presented.
Cole, L.T.; Allen, C.A.
Behavior of the particle transport coefficients near the density limit in MTX
The perturbed particle transport coefficients were determined for a range of plasma conditions in the Alcator C tokamak, a component of the Microwave Tokamak Experiment (MTX), from analysis of density perturbations created in gas modulation experiments. Density measurements from a 15 chord far-infrared interferometer were sufficiently detailed to allow radial profiles of the transport coefficients to be resolved. Gas modulation experiments were carried out on plasmas over a range of relatively low currents and a wide variety of line-averaged densities, including values near the Greenwald density limit. With this technique the perturbed diffusion coefficient D and the perturbed convection velocity V can be determined simultaneously. Measured profiles of D rise toward the outside of the plasma column in a manner generally similar to those determined previously for {chi}{sub e,HP} from sawtooth heat pulse propagation. Values of D are typically smaller than those of {chi}{sub e,HP} given for the same line-averaged densities by a factor of 2-5. Diffusion coefficients from a series of discharges at constant current showed little variation with density through most of the saturated ohmic confinement regime. At the Greenwald density limit threshold a dramatic increase occurred in both the perturbed convective and diffusive transport coefficients in the outer region of the plasma. The increases were most pronounced at the outermost range of the radii where coefficients were determined (r/a = 0.8), but were apparent over a region which extended well into the plasma interior. Density profiles maintained a similar shape near the density limit, congruous with the similar behavior of the transport coefficients. No dramatic deterioration was evident in the global energy confinement.
Marinak, M.M.
Shear Viscosity Coefficient from Microscopic Models
The transport coefficient of shear viscosity is studied for a hadron matter through microscopic transport model, the Ultra--relativistic Quantum Molecular Dynamics (UrQMD), using the Green--Kubo formulas. Molecular--dynamical simulations are performed for a system of light mesons in a box with periodic boundary conditions. Starting from an initial state composed of $\\pi, \\eta ,\\omega ,\\rho ,\\phi$ with a uniform phase--space distribution, the evolution takes place through elastic collisions, production and annihilation. The system approaches a stationary state of mesons and their resonances, which is characterized by common temperature. After equilibration, thermodynamic quantities such as the energy density, particle density, and pressure are calculated. From such an equilibrated state the shear viscosity coefficient is calculated from the fluctuations of stress tensor around equilibrium using Green--Kubo relations. We do our simulations here at zero net baryon density so that the equilibration times depend on the energy density. We do not include hadron strings as degrees of freedom so as to maintain detailed balance. Hence we do not get the saturation of temperature but this leads to longer equilibration times.
Azwinndini Muronga
Diversity and Educational Gains: a plan for a changing county and its schools
Brown School not included because it is K-12 Diversity andEducational Gains Diversity and Educational GainsTeachers College Press. Diversity and Educational Gains
Orfield, Gary; Frankenberg, Erica
#12;ABSORPTION HEAT PUMP IN THE DISTRICT HEATING PLANT Dr.sc.ing. Agnese Lickrastina M.Sc. Normunds European Heat Pump Summit 2013, Nuremberg, 15-16.10.2013 · Riga District Heating company · Operation #12;JSC RGAS SILTUMS · the biggest District Heating company in Latvia and in the Baltic states
Oak Ridge National Laboratory
Electrically heated liquid tank employing heat pipe heat transfer means
The heating apparatus for applying heat to the interior of a chamber includes a modular, removable, electrical, heat-producing unit and a heat pipe mountable in a wall of the chamber with one end of the pipe arranged to receive heat from the electrical heat producing unit exterior of the housing and with another end of the pipe constructed and arranged to apply heat to the medium within the chamber. The heat pipe has high conductivity with a low temperature differential between the ends thereof and the heat producing unit includes an electric coil positioned about and removably secured to the one end of the heat pipe. The electric coil is embedded in a high thermal conducitivity, low electrical conductivity filler material which is surrounded by a low thermal conductivity insulating jacket and which is received around a metal core member which is removably secured to the one end of the heat pipe.
Shutt, J.R.
Solar heat collector
A solar heat collector comprises an evacuated transparent pipe; a solar heat collection plate disposed in the transparent pipe; a heat pipe, disposed in the transparent pipe so as to contact with the solar heat collection plate, and containing an evaporable working liquid therein; a heat medium pipe containing a heat medium to be heated; a heat releasing member extending along the axis of the heat medium pipe and having thin fin portions extending from the axis to the inner surface of the heat medium pipe; and a cylindrical casing surrounding coaxially the heat medium pipe to provide an annular space which communicates with the heat pipe. The evaporable working liquid evaporates, receiving solar heat collected by the heat collection plate. The resultant vapor heats the heat medium through the heat medium pipe and the heat releasing member.
Yamamoto, T.; Imani, K.; Sumida, I.; Tsukamoto, M.; Watahiki, N.
Heat Exchangers
Table 16 Ceramic heat exchanger systems...Soaking pit 870�??1230 1600�??2250 Fe, Si, alkalis Solar Turbines �?� 4�??8 OD �? 180 long (440 tubes) Aluminum melt furnaces 1010 1850 Alkali salts Plate fin GTE 0.6, 1.6 25�??46 Multiple 870�??1370 1600�??2250 Clean (good), alkalis (poor) Coors 0.25, 1.0 30 �? 30 �? 46 Multiple Clean (good), alkalis (poor) Radiant...
Heat transfer in bundles of finned tubes in crossflow
This book provides correlations of heat transfer and hydraulic data for bundles of finned tubes in crossflow at high Reynolds numbers. Results of studies of the effectiveness of the fin, local, and mean heat transfer coefficients are presented. The effect of geometric parameters of the fins and of the location of tubes in the bundle on heat transfer and hydraulic drag are described. The resistance of the finned tube bundles under study and other factors are examined.
Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.; Hewitt, G.F.
Low Cost High Performance Generator Technology Program. Volume 5. Heat pipe topical, appendices
Work performed by Dynatherm Corporation for Teledyne Isotopes during a program entitled ''Heat Pipe Fabrication, Associated Technical Support and Reporting'' is reported. The program was initiated on November 29, 1972; the main objectives were accomplished with the delivery of the heat pipes for the HPG. Life testing of selected heat pipe specimens is continuing to and beyond the present date. The program consisted of the following tasks: Heat Pipe Development of Process Definition; Prototype Heat Pipes for Fin Segment Test; HPG Heat Pipe Fabrication and Testing; Controlled Heat Pipe Life Test; and Heat Pipe Film Coefficient Determination. (TFD)
Geothermal district heating systems
Ten district heating demonstration projects and their present status are described. The projects are Klamath County YMCA, Susanville District Heating, Klamath Falls District Heating, Reno Salem Plaza Condominium, El Centro Community Center Heating/Cooling, Haakon School and Business District Heating, St. Mary's Hospital, Diamond Ring Ranch, Pagosa Springs District Heating, and Boise District Heating.
Budney, G.S.; Childs, F.
Enhanced two phase flow in heat transfer systems
A family of structures and designs for use in devices such as heat exchangers so as to allow for enhanced performance in heat exchangers smaller and lighter weight than other existing devices. These structures provide flow paths for liquid and vapor and are generally open. In some embodiments of the invention, these structures can also provide secondary heat transfer as well. In an evaporate heat exchanger, the inclusion of these structures and devices enhance the heat transfer coefficient of the evaporation phase change process with comparable or lower pressure drop.
Tegrotenhuis, Ward E; Humble, Paul H; Lavender, Curt A; Caldwell, Dustin D
GAINS: an interactive tool for assessing international GHG mitigation regimes
Mitigating greenhouse gases (GHGs) is key to reducing the longterm impacts of climate change. In this paper we present the GAINS system, i.e. a data warehouse with an online integrated assessment model that is already used in various international policy ... Keywords: GAINS, data warehouse
Thanh Binh Nguyen; Fabian Wagner; Wolfgang Schoepp
Solar assisted heat pump on air collectors: A simulation tool
The heating system of the bioclimatic building of the Greek National Centre for Renewable Energy Sources (CRES) comprises two heating plants: the first one includes an air source heat pump, Solar Air Collectors (SACs) and a heat distribution system (comprising a fan coil unit network); the second one is, mainly, a geothermal heat pump unit to cover the ground floor thermal needs. The SAC configuration as well as the fraction of the building heating load covered by the heating plant are assessed in two operation modes; the direct (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but indirectly into the evaporator of the air source heat pump). The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, saving electrical power consumed by the compressor of the heat pump, and therefore, at optimizing the coefficient of performance (COP) of the heat pump due to the increased intake of ambient thermal energy by means of the SAC. Results are given for three research objectives: assessment of the heat pump efficiency whether in direct or indirect heating mode; Assessment of the overall heating plant efficiency on a daily or hourly basis; Assessment of the credibility of the suggested simulation model TSAGAIR by comparing its results with the TRNSYS ones. (author)
Karagiorgas, Michalis; Galatis, Kostas; Tsagouri, Manolis [Department of Mechanical Engineering Educators, ASPETE, N. Iraklio, GR 14121 (Greece); Tsoutsos, Theocharis [Environmental Engineering Dept., Technical University of Crete, Technical University Campus, GR 73100, Chania (Greece); Botzios-Valaskakis, Aristotelis [Centre for Renewable Energy Sources (CRES), 19th km Marathon Ave., GR 19001, Pikermi (Greece)
Gaines County Solid Waste Management Act (Texas) | Department of Energy
Gaines County Solid Waste Management Act (Texas) Gaines County Solid Waste Management Act (Texas) Gaines County Solid Waste Management Act (Texas) < Back Eligibility Commercial Construction Industrial Investor-Owned Utility Local Government Municipal/Public Utility Rural Electric Cooperative Tribal Government Utility Program Info State Texas Program Type Environmental Regulations Provider Gaines County Solid Waste Management District This Act establishes the Gaines County Solid Waste Management District, a governmental body to develop and carry out a regional water quality protection program through solid waste management and regulation of waste disposal. The District has the power to prepare, adopt plans for, purchase, obtain permits for, construct, acquire, own, operate, maintain, repair, improve, and extend inside and outside the boundaries of the district any works,
Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) | Open
Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) Jump to: navigation, search Tool Summary Name: Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) Agency/Company /Organization: International Institute for Applied Systems Analysis (IIASA) Sector: Energy, Land Topics: Co-benefits assessment, GHG inventory Resource Type: Software/modeling tools User Interface: Website Complexity/Ease of Use: Not Available Website: gains.iiasa.ac.at/index.php/home-page/241-on-line-access-to-gains Cost: Free UN Region: Eastern Africa, Middle Africa, Northern Africa, Southern Africa, Western Africa, Caribbean, Central America, South America, Northern America, Central Asia, Eastern Asia, Southern Asia, South-Eastern Asia, Western Asia, Eastern Europe, Northern Europe, Southern Europe, Western Europe, Australia and New Zealand, Melanesia, Micronesia, Polynesia
It is recognized that detailed models of proposed hydrogen storage systems are essential to gain insight into the complex processes occurring during the charging and discharging processes. Such insight is an invaluable asset for both assessing the viability of a particular system and/or for improving its design. The detailed models, however, require time to develop and run. Clearly, it is much more efficient to begin a modeling effort with a good system design and to progress from that point. To facilitate this approach, it is useful to have simplified models that can quickly estimate optimal loading and discharge kinetics, effective hydrogen capacities, system dimensions and heat removal requirements. Parameters obtained from these models can then be input to the detailed models to obtain an accurate assessment of system performance that includes more complete integration of the physical processes. This report describes three scoping models that assess preliminary system design prior to invoking a more detailed finite element analysis. The three models address the kinetics, the scaling and heat removal parameters of the system, respectively. The kinetics model is used to evaluate the effect of temperature and hydrogen pressure on the loading and discharge kinetics. As part of the kinetics calculations, the model also determines the mass of stored hydrogen per mass of hydride (in a particular reference form). As such, the model can determine the optimal loading and discharge rates for a particular hydride and the maximum achievable loading (over an infinite period of time). The kinetics model developed with the Mathcad{reg_sign} solver, runs in a mater of seconds and can quickly be used to identify the optimal temperature and pressure for either the loading or discharge processes. The geometry scoping model is used to calculate the size of the system, the optimal placement of heat transfer elements, and the gravimetric and volumetric capacities for a particular geometric configuration and hydride. This scoping model is developed in Microsoft Excel{reg_sign} and inputs the mass of hydrogen to be stored, mass of stored hydrogen to mass of hydride (from the kinetics model), component densities, etc. The heat removal scoping model is used to calculate coolant flowrates, pressure drops and temperature increases over the length of the cooling channels. The model also calculates the convection heat transfer coefficient required to remove the heat of reaction associated with hydrogen uptake. The heat removal model inputs dimensions and the mass of hydrogen to be stored directly from the geometry scoping model. Additionally, the model inputs the heats of reaction, the thermal properties of the coolant and the time required to charge the bed.
Hardy, B
Effect of Cavity Wall Temperature and Opening Ratio on the Natural Convection Heat Loss Characteristics of a Solar Cavity Receiver
The natural convection heat loss characteristics of a solar cavity receiver have been investigated by numerical simulation method. The results show that, the natural convection heat loss, the convection heat transfer coefficient and Nusselt number increase ... Keywords: solar cavity receiver, cavity wall temperature, opening ratio, natural convection heat loss
Lan Xiao; Shuang-Ying Wu; You-Rong Li
Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders
Heat pipe embedded aluminum silicon carbide (AlSiC) plates are innovative heat spreaders that provide high thermal conductivity and low coefficient of thermal expansion (CTE). Since heat pipes are two phase devices, they demonstrate effective thermal conductivities ranging between 50,000 and 200,000 W/m-K, depending on the heat pipe length. Installing heat pipes into an AlSiC plate dramatically increases the plate�s effective thermal conductivity. AlSiC plates alone have a thermal conductivity of roughly 200 W/m-K and a CTE ranging from 7-12 ppm/ deg C, similar to that of silicon. An equivalent sized heat pipe embedded AlSiC plate has effective thermal conductivity ranging from 400 to 500 W/m-K and retains the CTE of AlSiC.
Johnson, Matthew (DOE/NNSA Kansas City Plant (United States)); Weyant, J.; Garner, S. (Advanced Cooling Technologies, Inc. (Lancaster, PA (United States)); Occhionero, M. (CPS Technologies Corporation, Norton, MA (United States))
Heat pump system
An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchanges and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.
Swenson, Paul F. (Cleveland, OH); Moore, Paul B. (Fedhaurn, FL)
An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchangers and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.
Energy Basics: Radiant Heating
very low heat capacity and have the quickest response time of any heating technology. More Information Visit the Energy Saver website for more information about radiant heating...
low heat capacity and have the quickest response time of any heating technology. More Information Visit the Energy Saver website for more information about radiant heating in homes...
New crop coefficients developed for high-yield processing tomatoes
after planting Fig. 2. Daily crop coefficients with daysFor all years, seasonal crop ETc ranged from 20.8 to 29.64. Relationship between average crop coefficient and canopy
Hanson, Blaine R.; May, Donald M.
Asymptotic normalization coefficients from ab initio calculations.
We present calculations of asymptotic normalization coefficients (ANCs) for one-nucleon removals from nuclear states of mass numbers 3 {le} A {le} 9. Our ANCs were computed from variational Monte Carlo solutions to the many-body Schroedinger equation with the combined Argonne v{sub 18} two-nucleon and Urbana IX three-nucleon potentials. Instead of computing explicit overlap integrals, we applied a Green function method that is insensitive to the difficulties of constructing and Monte Carlo sampling the long-range tails of the variational wave functions. This method also allows computation of the ANC at the physical separation energy, even when it differs from the separation energy for the Hamiltonian. We compare our results, which for most nuclei are the first ab initio calculations of ANCs, with existing experimental and theoretical results and discuss further possible applications of the technique.
Nollett, K. M.; Wiringa, R. B. (Physics)
A Study of the Irradiation-Temperature Coefficient for Alanine ...
A Study of the Irradiation-Temperature Coefficient for Alanine Film and Pellet Dosimeters at Elevated Temperature. ...
A new numerical method for conversion of sonic second virial coefficients to density second virial coefficients
A new numerical method has been developed for calculation of density second virial coefficients, B(T), from sonic velocity measurements in gases at low pressures. Unlike existing methods, this procedure requires no model assumption as to the form of the temperature variation of B(T). Rather it gathers additional information by differencing the measured acoustic second virial coefficient in accordance with a new mathematical approximation. While two higher-ordered terms in the complete identity must be ignored to initiate the numerical calculations, the magnitude of these terms can later be estimated from the initial determination of B(T). By such an iterative procedure, the method can be made exact or, from a second viewpoint, the initial estimate allows calculation of the errors in the method itself. The new method is simple and easy to use as it employs only standard numerical techniques. It requires a digital computer program; although limited calculations can be made on a modern hand-held calculator. The objectives of this research are (1) to prove that our method is more accurate than existing methods for extracting second density virial coefficients from sonic velocity data, (2) to illustrate that the new numerical method is much simpler in convening sonic velocity data to second density virial coefficients and finally (3) to show that with the new method, no model assumptions for the temperature profile need to be made to get accurate results.
Mossaad, Ehab
Heat transfer and heat exchangers reference handbook
The purpose of this handbook is to provide Rocky Flats personnel with an understanding of the basic concepts of heat transfer and the operation of heat exchangers.
Heating systems for heating subsurface formations
Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.
Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)
A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.
Brackenbury, Phillip J. (Richland, WA)
ANN and ANFIS models for performance evaluation of a vertical ground source heat pump system
The aim of this study is to demonstrate the comparison of an artificial neural network (ANN) and an adaptive neuro-fuzzy inference system (ANFIS) for the prediction performance of a vertical ground source heat pump (VGSHP) system. The VGSHP system using ... Keywords: Adaptive neuro-fuzzy inference system, Coefficient of performance, Ground source heat pump, Membership functions, Vertical heat exchanger
Hikmet Esen; Mustafa Inalli
Performance prediction of a ground-coupled heat pump system using artificial neural networks
This paper describes the applicability of artificial neural networks (ANNs) to predict performance of a horizontal ground-coupled heat pump (GCHP) system. Performance forecasting is the precondition for the optimal control and energy saving operation ... Keywords: Artificial neural network, Coefficient of performance, Ground-coupled heat pump, Horizontal heat exchanger, Learning algorithm
Hikmet Esen; Mustafa Inalli; Abdulkadir Sengur; Mehmet Esen
Geothermal groundwater heat pump. Equipment selection procedures for architects, designers and contractors
This brochure covers the following: the way the heat pump works, why use groundwater, groundwater availability and disposal, regulations, the coefficient of performance, heat pump maintenance and reliability, heating and cooling load calculations, fuel requirement calculations, choice of equipment, calculation of water flow requirement, well pump and supply/return pipes, and design examples. (MHR)
Geothermal field tests: heat exchanger evaluation
Results of the heat exchanger tests conducted on a scale model of a heat exchanger that has been designed and fabricated for the Geothermal Test Facility show that this exchanger will lose 60% of its heat transfer capability and fall below design requirements after 92 hours of operation. When the test exchanger was clean and operating as close as possible to design conditions, its overall heat transfer coefficient was 426 BTU/hr-ft/sup 2/ - /sup 0/f. when calculating in the fouling factor of .0035 this gave a design coefficient of 171 BTU/hr-ft/sup 2/ - /sup 0/f which was reached after less than four days of steady state operation. Thermal shocking of the test heat exchanger once each hour while the exchanger was operating at design conditions had no effect on scale removal or heat transfer. Results of tube cleaning showed that chemical treatment with 30% hydrochloric acid followed by a high pressure water jet (6000 psig), was effective in removing scale from tubes contacted with geothermal brine. After cleaning, the tubes were examined and some pitting was observed throughout the length of one tube.
Felsinger, D.E.
Heat-driven acoustic cooling engine having no moving parts
A heat-driven acoustic cooling engine having no moving parts receives heat from a heat source. The acoustic cooling engine comprises an elongated resonant pressure vessel having first and second ends. A compressible fluid having a substantial thermal expansion coefficient and capable of supporting an acoustic standing wave is contained in the resonant pressure vessel. The heat source supplies heat to the first end of the vessel. A first heat exchanger in the vessel is spaced-apart from the first end and receives heat from the first end. A first thermodynamic element is adjacent to the first heat exchanger and converts some of the heat transmitted by the first heat exchanger into acoustic power. A second thermodynamic element has a first end located spaced-apart from the first thermodynamic element and a second end farther away from the first thermodynamic element than is its first end. The first end of the second thermodynamic element heats while its second end cools as a consequence of the acoustic power. A second heat exchanger is adjacent to and between the first and second thermodynamic elements. A heat sink outside of the vessel is thermally coupled to and receives heat from the second heat exchanger. The resonant pressure vessel can include a housing less than one-fourth wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir.
Wheatley, John C. (Los Alamos, NM); Swift, Gregory W. (Santa Fe, NM); Migliori, Albert (Santa Fe, NM); Hofler, Thomas J. (Los Alamos, NM)
Radiofrequency plasma heating: proceedings
The conference proceedings include sessions on Alfven Wave Heating, ICRF Heating and Current Drive, Lower Hybrid Heating and Current Drive, and ECRF Heating. Questions of confinement, diagnostics, instabilities and technology are considered. Individual papers are cataloged separately. (WRF)
Swenson, D.G. (ed.)
Achieving improved cycle efficiency via pressure gain combustors
As part of the Department of Energy`s Advanced Gas Turbine Systems Program, an investigation is being performed to evaluate ``pressure gain`` combustion systems for gas turbine applications. This paper presents experimental pressure gain and pollutant emission data from such combustion systems. Numerical predictions for certain combustor geometries are also presented. It is reported that for suitable aerovalved pulse combustor geometries studied experimentally, an overall combustor pressure gain of nearly 1 percent can be achieved. It is also shown that for one combustion system operating under typical gas turbine conditions, NO{sub x} and CO emmissions, are about 30 ppmv and 8 ppmv, respectively.
Gemmen, R.S.; Janus, M.C.; Richards, G.A.; Norton, T.S. [USDOE Morgantown Energy Technology Center, WV (United States); Rogers, W.A. [EG& G Technical Services of West Virginia, Morgantown, WV (United States)
Design of a high-gain flux-compression generator
The current gain of a high-gain, high-explosive helical magnetic-flux-compression generator (HEG) is limited both by nonuniformities in stator expansion and by armature-stator misalignment. We set out to achieve three goals: first, an output current of at least 2 MA with a current gain greater than 1000 to drive a 150- to 300-nH load; second, a generator with an acceptably small volume and length; and finally, generator output of a reliable magnitude. 5 refs., 6 figs.
Pincosy, P.A.; Abe, D.K.; Chase, J.B. (Lawrence Livermore National Lab., CA (USA))
Measuring solar heat reduction for draperies and fabric shades
We are all familiar with the utility of draperies, curtains and shades to exclude unwanted solar gain, control glare, insulate windows and provide privacy. The manageability of these devices gives us a degree of control over our indoor environment. While fabric window coverings are widely used as interior shading devices, the analytical methods used to determine their effectiveness in reducing solar gains are relatively unsophisticated. Furthermore, with the recent emphasis on daylighting and visual and thermal comfort, the response to these shading devices to the varying direction of incident solar radiation has taken on a new importance. In this article, the authors review the historical development of analytical and experimental methods used to determine solar heat gain for draperies. The current state of these methods will be evaluated and issues related to their applicability to draperies and fabric shades are identified. Finally, recommendations to improve the accuracy and applicability of current solar heat gain methods are presented.
Grasso, M.M.; Hunn, B.D. (Univ. of Texas, Austin, TX (US))
Photovoltaic roof heat flux
and could the heat transfer processes be modeled to estimateindicating that the heat transfer processes were modeled w i
Samady, Mezhgan Frishta
Heat pipe methanator
A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.
Ranken, William A. (Los Alamos, NM); Kemme, Joseph E. (Los Alamos, NM)
taper mea- surements from LCLS. We ?nd gain lengths of ? 2.9AND TAPER MEASUREMENTS AT LCLS ? D. Ratner � , A. Brachmann,et al. , First Results of the LCLS Laser-Heater Sys- tem,
Ratner, D.
Gain-assisted control of the Goos-Haenchen shift
A gain-assisted model is considered to study the Goos-Haenchen (GH) shift behavior in the reflected and transmitted light. In this model, a probe light is incident on a cavity containing three-level dilute gaseous atomic medium. The atom-field interaction follows two-photon Raman transitions, and the dielectric susceptibility of the medium exhibits dispersion and gain properties [L. J. Wang, A. Kuzmich, and A. Dogariu, Nature (London) 406, 227 (2000)]. Under appropriate conditions, two gain peaks are observed with anomalous dispersion between the peaks, whereas normal dispersion can be observed at and around the gain maxima. The manipulation of the detuning associated with the probe light field which interacts with the intracavity medium during its propagation through the cavity can lead to a control over negative and positive GH shift in the reflected and transmitted light beam via the anomalous and normal dispersion of the medium.
Ziauddin,; Qamar, Sajid [Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)
U-030: Apache Tomcat Lets Untrusted Web Applications Gain Elevated
30: Apache Tomcat Lets Untrusted Web Applications Gain Elevated 30: Apache Tomcat Lets Untrusted Web Applications Gain Elevated Privileges U-030: Apache Tomcat Lets Untrusted Web Applications Gain Elevated Privileges November 9, 2011 - 8:30am Addthis PROBLEM: Apache Tomcat Lets Untrusted Web Applications Gain Elevated Privileges. PLATFORM: Apache Tomcat 7.0.0-7.0.21. ABSTRACT: An untrusted web application can access Manager application functions. reference LINKS: Apache Tomcat 7.x vulnerabilities SecurityTracker Alert ID: 1026295 CVE-2011-3376 IMPACT ASSESSMENT: Medium Discussion: A vulnerability was reported in Apache Tomcat. A local user (application) can obtain elevated privileges on the target system. A local web application (that is not trusted) can access Manager application functions without being marked as privileged. This can be exploited to obtain
DOE Program Offers Participants Unique Opportunity to Gain Carbon Capture
Program Offers Participants Unique Opportunity to Gain Carbon Program Offers Participants Unique Opportunity to Gain Carbon Capture and Storage Knowledge DOE Program Offers Participants Unique Opportunity to Gain Carbon Capture and Storage Knowledge February 8, 2011 - 12:00pm Addthis Washington, DC - Future leaders and innovators in the area of carbon capture and storage (CCS) can gain a unique and intensive tutorial on the subject by participating in the U.S. Department of Energy's (DOE) Research Experience in Carbon Sequestration (RECS) program. Supported by the Office of Fossil Energy (FE), the program for graduate students and early career professionals is currently accepting applications for RECS 2011, scheduled for June 5-15, in Birmingham, AL, and the deadline to apply is April 15. An intensive science-based program, RECS 2011 will combine classroom
Segmented heat exchanger
A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.
Baldwin, Darryl Dean (Lafayette, IN); Willi, Martin Leo (Dunlap, IL); Fiveland, Scott Byron (Metamara, IL); Timmons, Kristine Ann (Chillicothe, IL)
Dual source heat pump
What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.
Ecker, Amir L. (Dallas, TX); Pietsch, Joseph A. (Dallas, TX)
We have investigated the reaction of room-temperature silane and disilane on a hot polycrystalline silicon surface using both a collision-free molecular beam and a very low pressure CVD cell. Reactive sticking coefficients were obtained from deposition rate data over a wide range of temperatures and silane (disilane) fluxes. The RSCs are substantially less than one, ranging from 6 x 10/sup -5/ to 4 x 10/sup -2/. For silane we observed curved Arrhenius plots with slopes decreasing from approx.60 kcal mol/sup -1/ at low temperatures to approx.2 kcal mol/sup -1/ at higher temperatures. The RSCs are independent of flux (pressure) at 1040/sup 0/C, but vary as flux to the approx.-1/2 power at 710/sup 0/C. A model comprised of a dissociative adsorption mechanism with competing associative desorption and reaction was found to give reasonable agreement. For disilane, we observed RSCs that were roughly ten times higher than those for silane. We also observed a curved Arrhenius plot and a flux dependence at 710/sup 0/C for disilane. 22 refs., 5 figs.
Use of SCALE Continuous-Energy Monte Carlo Tools for Eigenvalue Sensitivity Coefficient Calculations
The TSUNAMI code within the SCALE code system makes use of eigenvalue sensitivity coefficients for an extensive number of criticality safety applications, such as quantifying the data-induced uncertainty in the eigenvalue of critical systems, assessing the neutronic similarity between different critical systems, and guiding nuclear data adjustment studies. The need to model geometrically complex systems with improved fidelity and the desire to extend TSUNAMI analysis to advanced applications has motivated the development of a methodology for calculating sensitivity coefficients in continuous-energy (CE) Monte Carlo applications. The CLUTCH and Iterated Fission Probability (IFP) eigenvalue sensitivity methods were recently implemented in the CE KENO framework to generate the capability for TSUNAMI-3D to perform eigenvalue sensitivity calculations in continuous-energy applications. This work explores the improvements in accuracy that can be gained in eigenvalue and eigenvalue sensitivity calculations through the use of the SCALE CE KENO and CE TSUNAMI continuous-energy Monte Carlo tools as compared to multigroup tools. The CE KENO and CE TSUNAMI tools were used to analyze two difficult models of critical benchmarks, and produced eigenvalue and eigenvalue sensitivity coefficient results that showed a marked improvement in accuracy. The CLUTCH sensitivity method in particular excelled in terms of efficiency and computational memory requirements.
Perfetti, Christopher M [ORNL; Rearden, Bradley T [ORNL
Heat reclaimer for a heat pump
This invention relates to a heat reclaiming device for a heat pump. The heat reclaimer is able to absorb heat from the compressor by circulating cooling fluid through a circuit which is mounted in good heat transfer relationship with the condenser, then around the shell of the motor-compressor and lastly around the hollow tube which connects the condenser to the compressor. The reclaiming circuit is connected into a fluid circulating loop which is used to supply heat to the evaporator coil of the heat pump.
Beacham, W.H.
Design of a variable gain amplifier for an ultrawideband receiver
A fully differential CMOS variable gain amplifier (VGA) has been designed for an ultra-wideband receiver. The VGA comprises of two variable gain stages followed by a post amplifier stage. The interface between the digital control block and the analog VGA is formed by a digital-to-analog converter and an exponential voltage generator. The gain of the VGA varies dB-linearly from 0 to 52 dB with respect to the control voltage. The VGA is operated in open loop with a bandwidth greater than 500 MHz throughout the gain range to cater to the requirements of the ultra-wideband system. The noise-to-power ratio of the VGA is -23.9 dB for 1Vp-p differential input signal in the low gain setting, and the equivalent input referred noise is 1.01 V2 for the high gain setting. All three stages use common mode feedback to fix and stabilize the output DC levels at a particular voltage depending on the input common-mode requirement of the following stage. DC offset cancellation has also been incorporated to minimize the input referred DC offset caused by systematic and random mismatches in the circuit. Compensation schemes to minimize the effects of temperature, supply and process variations have been included in the design. The circuit has been designed in 0.18??m CMOS technology, and the post layout simulations are in good agreement with the schematic simulations.
Krishnanji, Sivasankari
Experimental testing and analytical analysis of a plastic panel heat exchanger for greenhouse heating
The performance of a plastic panel-type heat exchanger, suitable for greenhouse heating using low-grade (25 to 60/sup 0/C water) power plant reject heat, was investigated theoretically and experimentally. The theoretical analysis showed that a plastic panel heat exchanger would have an overall heat transfer coefficient, U/sub 0/, of about 18 w/m/sup 2/-/sup 0/C compared to about 12 w/m/sup 2/-/sup 0/C for a fin-tube heat exchanger, under typical greenhouse conditions. Furthermore the plastic heat exchanger would require less fan power due to reduced air pressure losses. The experimental data revealed a similar functional relationship for U/sub 0/ and air flow when compared with the theoretical calculations, however the experimental values of U/sub 0/ were consistently larger by 20 to 30%. It was concluded that a properly designed plastic heat exchanger can compete with metal fin tube type exchangers on a performance basis, but the plastic heat exchangers are 3 to 4 times larger by volume. However, because of the lower cost of plastic, a substantial cost reduction is expected. It appears that further study, examining heat exchanger lifetime, performance and costs, is warranted.
Olszewski, M.; Thomas, J.F.
Heat transfer research and power cycle transient modeling
Fine axial flutes enhance heat transfer in vertical shell-and-tube exchangers with water inside the tubes and ammonia evaporating or condensing in layer flow on the shell side. Single-tube experiments with R-11 and ammonia indicate local shell-side coefficients 3 to 5 times those for corresponding smooth tubes. Single-tube experiments with water indicate that at moderate velocities the tube-side coefficients are enhanced by a factor equal to the ratio of fluted-to-smooth surface areas while the fluid friction is similarly increased. The experimental data are transformed into mean individual coefficients for ammonia and water. Overall coefficients for a particular case are presented to illustrate the efficacy of enhancement by flutes on one or both sides of the heat transfer surface. Means are described for using emerging data to predict the static and dynamic behavior of the power cycle and the interactions of components throughout the complete power plant.
Rothfus, R.R.; Neuman, C.P.
A Computational Study on the Thermal-Hydraulic Behavior of Supercritical Carbon Dioxide in Various Printed Circuit Heat Exchanger Designs
There has been an ever-increasing demand for power generation, which is predicted to grow as society becomes more advanced. However, tradition fossil fuels are beginning to deplete, and there is a great necessity for alternative fuel sources that will bridge the gap between energy production and consumption. To decrease the high demand alternative fuel sources are gaining in popularity. The supercritical carbon dioxide Brayton power cycle has been proposed as a possible cycle for nuclear and concentrated solar power generation. Two main advantages of having supercritical carbon dioxide are the large property variations and component size associated with power cycle. Forced convection heat transfer of supercritical carbon dioxide in printed circuit heat exchanger geometries were investigated in the following study using a finite volume framework and the FLUENT 12.1 code. The geometries of interest were: non- chamfered zig-zag, chamfered zig-zag, and air foil. Flow through the three geometries was in the horizontal orientation and subject to a heating mode operation. A range of testing conditions were explored, including operating pressures between 7.5 to 10.2 MPa with the mass flux ranging from 326 to 762 kg/m2-s. Due to the turbulent nature of this problem, the k?E with enhanced wall treatment and shear stress transport k?? turbulence models were considered. With this addition a total of 54 simulations were performed. Results indicated that there was an increase in the heat transfer coefficient as the supercritical carbon dioxide reached the pseudocritical temperature, conversely as there was an increase in operating pressure, the heat transfer coefficient decreased. Nevertheless, this increase near the pseudocritical temperature was due to a sharp increase in the specific heat. Mass flux effects indicated that there was an increase in heat transfer as the mass flux was increased. This was due to the increase in Reynolds number near the pseudocritical temperature. Next, pressure losses were investigated for the three geometries. The non-chamfered zig-zag channel had the greatest pressure loss associated with it, while the air foil channel had the least. Based on the results, the ratio of the friction factor to heat transfer for the non-chamfered and chamfered zig-zag geometries were approximately 2.65 and 1.57 times higher than for the air foil, thus leading to the idea that the air foil channel may be best suited for practical applications. Finally, the simulation results were compared to experimental data and existing correlations. Many existing correlations failed to accurately predict the magnitude of heat transfer, although they exhibited a similar trend. A new correlation was developed for the zig-zag geometries based on the numerical data obtained during this investigation and published experimental data. The new correlation is able to predict the maximum heat transfer coefficient within 12.4%.
Matsuo, Bryce
Design and Testing of Metal and Silicon Heat Spreaders with Embedded Micromachined Heat Pipes
The authors have developed a new type of heat spreader based on the integration of heat pipes directly within a thin planar structure suitable for use as a heat spreader or as the base layer in a substrate. The process uses micromachining methods to produce micron scale patterns that act as a wick in these small scale heat pipes. By using silicon or a low expansion metal as the wall material of these spreaders, they achieve a good match to the thermal coefficient of expansion of the die. The match allows the use of a thin high performance die attachment even on large size die. The embedded heat pipes result in high effective thermal conductivity for the new spreader technology.
Benson, D.A.; Robino, C.V.
Novel heat pipe combination
The basic heat pipe principle is employed in a heat pipe combination wherein two heat pipes are combined in opposing relationship to form an integral unit; such that the temperature, heat flow, thermal characteristics, and temperature-related parameters of a monitored environment or object exposed to one end of the heat pipe combination can be measured and controlled by controlling the heat flow of the opposite end of the heat pipe combination.
Kinetics of nonisothermal adsorption by biporous adsorbents. Communication 6. Description of kinetic adsorption curves with account of the temperature dependence of the intracrystalline diffusion coefficients
An analytical description has been given of the kinetic adsorption curves with account of the influence of the change in adsorbent temperature due to the evolution of heat and adsorption on the coefficient of intracrystalline diffusion of the adsorbate. The deviation of the experimental kinetic curves for the adsorption of trans-2-butene by finely crystalline NaA zeolite from those calculated from the equation of isothermal diffusion is due to the influence of temperature on the coefficient of intracrystalline diffusion.
Broddak, R.; Voloshchuk, A.M.; Gorlov, V.A.; Dubinin, M.M.; Kochirzhik, M.
Multiple source heat pump
A heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating a fluid in heat exchange relationship with a refrigerant fluid, at least three refrigerant heat exchangers, one for effecting heat exchange with the fluid, a second for effecting heat exchange with a heat exchange fluid, and a third for effecting heat exchange with ambient air; a compressor for compressing the refrigerant; at least one throttling valve connected at the inlet side of a heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circuit and pump for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and directional flow of refrigerant therethrough for selecting a particular mode of operation. Also disclosed are a variety of embodiments, modes of operation, and schematics therefor.
Ecker, Amir L. (Duncanville, TX)
NIST X-Ray Mass Attenuation Coefficients - Version History
... year, month day with database access date.) Hubbell, JH and Seltzer, SM (2004), Tables of X-Ray Mass Attenuation Coefficients and Mass Energy- ...
Derivation of the coefficient squared probability law in quantum mechanics
If one assumes there is probability of perception in quantum mechanics, then unitarity dictates that it must have the coefficient squared form, in agreement with experiment.
Casey Blood
Kinetic theory of the interdiffusion coefficient in dense plasmas
Naive applications of Spitzer's theory to very dense plasmas can lead to negative diffusion coefficients. The interdiffusion coefficients in Binary Ionic Mixtures (two species of point ions in a uniform neutralizing background) have been calculated recently using molecular dynamics techniques. These calculations can provide useful benchmarks for theoretical evaluations of the diffusion coefficient in dense plasma mixtures. This paper gives a brief description of a kinetic theoretic approximation to the diffusion coefficient which generalizes Spitzer to high density and is in excellent agreement with the computer simulations. 15 refs., 1 fig., 2 tabs.
Boercker, D.B.
Natural convection heat exchangers for solar water heating systems. Technical progress report, July 15, 1996--September 14, 1996
This report very briefly summarizes project objectives, results, and current activities. The goals of the project are: (1) to develop guidelines for the design and use of thermosypohon side-arm heat exchangers in solar domestic water heating systems, and (2) to establish appropriate modeling and testing criteria for evaluating the performance of systems using this type of heat exchanger. Results include the experimental study of thermosyphon heat exchangers, which led to modeling equations that correlate the overall heat transfer coefficient-area product (UA) to mixed convection regime parameters. Current activities include the development and evaluation of a side-arm heat exchanger computer model and modification of the experimental facility for fundamental heat exchanger studies.
Natural convection heat exchangers for solar water heating systems. Technical progress report, May 15, 1996--July 14, 1996
This progress report very briefly summarizes study results and includes an experimental plan developed for the fundamental study of heat transfer in thermosyphon side-arm heat exchangers. The study will investigate the influence of the Reynolds and Grashof numbers on the thermosyphon flow side of the heat exchanger, and the influence of the flow rate on the forced flow side of the heat exchanger. Detailed temperature, flow rate, and pressure data will be obtained for four, seven, and nine tube-in-shell heat exchanger designs. Correlations will be developed for the heat transfer and friction coefficients, and a semi-empirical model will be developed to predict the performance of thermosyphon heat exchangers in solar water heaters.
Analysis of heat-pipe absorbers in evacuated-tube solar collectors
Heat transfer in evacuated-tube solar collectors with heat-pipe absorbers is compared with that for similar collectors with flow-through absorbers. In systems that produce hot water or other heated fluids, the heat-pipe absorber suffers a heat transfer penalty compared with the flow-through absorber, but in many cases the penalty can be minimized by proper design at the heat-pipe condenser and system manifold. The heat transfer penalty decreases with decreasing collector heat loss coefficient, suggesting that evacuated tubes with optical concentration are more appropriate for use with heat pipes than evacuated or nonevacuated flat-plate collectors. When the solar collector is used to drive an absorption chiller, the heat-pipe absorber has better heat transfer characteristics than the flow-through absorbers.
Hull, J.R.; Schertz, W.W.; Allen, J.W.
A FEM-based Inverse Calculation Method for Determination of Heat ...
Abstract Scope, Abstract:Heat transfer coefficient (HTC), as a criterion of cooling ... optimized multigrid scheme for computing unsteady incompressible fluid flow ... Implementation of Cross Slip Mechanisms in Discrete Dislocation Dynamics�...
Optimization of the controlling design parameters of fluidised bed gas-solid heat exchangers
Generalised analytical correlations relating heat transfer coefficient, mass velocity of gas, tube diameter, bed particle size and relative pitch have been formulated based on experimental data reported in literature. These correlations are used to predict ...
V. N. Vedamurthy; T. Janakirajan; S. Natarajan; C. P. Sarathy
Home Heating Systems Design using PHP and MySQL Databases
This paper presents the use of a computer application based on a MySQL database, managed by PHP programs, allowing the selection of a heating device using coefficient-based calculus.
Karnyanszky, Tiberiu Marius
The influence of return bends on the downstream pressure drop and condensation heat transfer in tubes
The influence of return bends on the downstream pressure drop and heat transfer coefficient of condensing refrigerant R-12 was studied experimentally. Flow patterns in glass return bends of 1/2 to 1 in. radius and 0.315 ...
Traviss, Donald P.
Industrial Waste Heat Recovery Using Heat Pipes
For almost a decade now, heat pipes with secondary finned surfaces have been utilized in counter flow heat exchangers to recover sensible energy from industrial exhaust gases. Over 3,000 such heat exchangers are now in service, recovering an estimated energy equivalent of nearly 1.1 million barrels of oil annually. Energy recovered by these units has been used to either preheat process supply air or to heat plant comfort make-up air. Heat pipe heat exchangers have been applied to an ever-expanding variety of industrial processes. One notable application in recent years has been for combustion airs preheat of fired heaters in petroleum refineries and petrochemical plants. Another recent development has been a waste heat recovery boiler using heat pipes. This device has a number of advantageous features. Field operational experience of several units in service has been excellent.
Ruch, M. A.
NREL: Continuum Magazine - Electric Vehicle Battery Development Gains
Electric Vehicle Battery Development Gains Momentum Electric Vehicle Battery Development Gains Momentum Issue 5 Print Version Share this resource Electric Vehicle Battery Development Gains Momentum CAEBAT collaboration targets EDV batteries with longer range and lifespan, at a lower cost. A photo of two men silhouetted in front of six back-lit display screens showing battery models, located in a dark room (22008). Enlarge image NREL's modeling, simulation, and testing activities include battery safety assessment, next-generation battery technologies, material synthesis and research, subsystem analysis, and battery second use studies. Photo by Dennis Schroeder, NREL "When people get behind the wheel of an electric car, it should be a great driving experience. Period." Dr. Taeyoung Han, GM technical fellow, said,
Two Savannah River Site Projects Gain National Recognition | Department of
Two Savannah River Site Projects Gain National Recognition Two Savannah River Site Projects Gain National Recognition Two Savannah River Site Projects Gain National Recognition June 21, 2011 - 12:00pm Addthis Media Contacts Jim Giusti, DOE (803) 952-7697 firstname.lastname@example.com Will Callicott, SRNL (803) 725-3786 firstname.lastname@example.com AIKEN, SC - The Department of Energy's Savannah River Site has received Environmental Sustainability (EStar) awards from DOE for two projects growing out of technology research, development and application at the Savannah River National Laboratory. EStar awards recognize excellence in pollution prevention and sustainable environmental stewardship. They are awarded for projects and programs that reduce environmental impacts, enhance site operations, and reduce costs. One award, for Renewable Technology Development, Deployment and Education
Additional solar/load ratio correlations for direct gain buildings
Solar/load ratio (SLR) correlations have been developed for two new reference direct gain designs. The new reference designs are identical to the originals except that the glazing air gap has been increased from 1/4 in. to 1/2 in. and a vector average of the local hourly windspeed was used in the thermal network calculations rather than an assumed average value of 15 m.p.h. Both of these modifications are realistic and enhance the predicted performance of direct gain buildings. A comprehensive set of mass sensitivity calculations has been performed in order to provide information needed to select an appropriate set of parameters for new lightweight direct gain designs for which additional SLR correlations will be developed. Representative results are reported.
Wray, W.O.
NREL: Energy Systems Integration - ESIF Gaining National and International
ESIF Gaining National and International Interest ESIF Gaining National and International Interest An aerial photo of the NREL Golden campus with arrows pointing to the ESIF building. The Energy Systems Integration Facility on the NREL campus in Golden, Colorado. Aerial photo taken 6/2012 by Sincere/Duncan Studios courtesy of JE Dunn Construction. As the October 2012 substantial completion of NREL's new Energy Systems Integration Facility approaches, interest in the facility is gaining momentum. Universities such as Stanford and MIT, as well as corporations such as Ingersoll-Rand and IBM, have already gotten a first look at the facility during its construction. In addition, international organizations such as E-Energy (Germany), Suzlon (India), and NEDO (Japan) are considering how they can partner with NREL to test renewable technologies
Savannah River Site Projects Gain National Recognition Savannah River Site Projects Gain National Recognition Two Savannah River Site Projects Gain National Recognition June 21, 2011 - 12:00pm Addthis Media Contacts Jim Giusti, DOE (803) 952-7697 firstname.lastname@example.com Will Callicott, SRNL (803) 725-3786 email@example.com AIKEN, SC - The Department of Energy's Savannah River Site has received Environmental Sustainability (EStar) awards from DOE for two projects growing out of technology research, development and application at the Savannah River National Laboratory. EStar awards recognize excellence in pollution prevention and sustainable environmental stewardship. They are awarded for projects and programs that reduce environmental impacts, enhance site operations, and reduce costs. One award, for Renewable Technology Development, Deployment and Education
Internships Help Future Energy Leaders Gain Hands-On Experience |
Internships Help Future Energy Leaders Gain Hands-On Experience Internships Help Future Energy Leaders Gain Hands-On Experience Internships Help Future Energy Leaders Gain Hands-On Experience August 23, 2013 - 10:19am Addthis EM Office of External Affairs Acting Communications Director Dave Borak talks with EM intern Valerie Edwards. | Photo courtesy of the Energy Department. EM Office of External Affairs Acting Communications Director Dave Borak talks with EM intern Valerie Edwards. | Photo courtesy of the Energy Department. Rebecca Matulka Rebecca Matulka Digital Communications Specialist, Office of Public Affairs More Back-To-School Stories: Learn how the Energy Department's Energy 101 Course Framework is helping colleges and universities offer energy-related classes. Interested in working at the National Labs? There's an internship
for Passive Passive Solar Heating Applications StephenHEAT MIRRORS FOR PASSIVE SOLAR HEATING APPLICATIONS StephenMIRRORS FOR PASSIVE SOLAR HEATING APPLICATIONS Stephen
Selkowitz, S.
Kethcum District Heating District Heating Low Temperature Geothermal...
Kethcum District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Kethcum District Heating District Heating Low Temperature Geothermal...
Midland District Heating District Heating Low Temperature Geothermal...
Midland District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Midland District Heating District Heating Low Temperature Geothermal...
Boise City Geothermal District Heating District Heating Low Temperatur...
Boise City Geothermal District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Boise City Geothermal District Heating District Heating...
San Bernardino District Heating District Heating Low Temperature...
Bernardino District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name San Bernardino District Heating District Heating Low Temperature...
Philip District Heating District Heating Low Temperature Geothermal...
Philip District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Philip District Heating District Heating Low Temperature Geothermal...
Pagosa Springs District Heating District Heating Low Temperature...
District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Pagosa Springs District Heating District Heating Low Temperature Geothermal...
City of Klamath Falls District Heating District Heating Low Temperatur...
District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name City of Klamath Falls District Heating District Heating Low Temperature...
Northeast Home Heating Oil Reserve System Heating Oil, PIA Office...
Northeast Home Heating Oil Reserve System Heating Oil, PIA Office of Fossil Energy Headquaters Northeast Home Heating Oil Reserve System Heating Oil, PIA Office of Fossil Energy...
Numerical Simulation of Thermal-Solid Coupling to Coal-Rock during the Process of Heat Injection Mine for CBM
For gaining effective influence radius of heat injection mine for CBM (Coal Bed Methane) and influence rules of permeability under the condition of temperature and effective stress, heat transfer and elastic mechanics theory combined, hooker law of thermal ... Keywords: heat injection, thermal-solid coupling, numerical simulation, effective influence radius, permeability
Xin Le Yang; Yong Li Zhang
Geothermal Heat Pumps
Geothermal heat pumps use the constant temperature of the earth as an exchange medium for heat. Although many parts of the country experience seasonal temperature extremes�from scorching heat in...
of ~24�C, indicating that heat conduction was small. T h i sday, indicating large heat conduction a n d storage. Control2.1.3 showed that conduction heat flux through the roof was
Absorption heat pump system
The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.
Grossman, Gershon (Oak Ridge, TN)
Grossman, G.
ON ~m Small Particle Heat Exchangers Arion J. Hunt June 1978d. LBL 7841 Small Particle Heat Exchangers by Arlon J. Huntgenerally to non-solar heat exchangers. These may be of the
Hunt, A.J.
Heat Pump Systems
Like a refrigerator, heat pumps use electricity to move heat from a cool space into a warm space, making the cool space cooler and the warm space warmer. Because they move heat rather than generate...
Woven heat exchanger
This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.
Piscitella, R.R.
A solar heat collector is described that pre-heats water for a household hot water heating system, and also heats the air inside a house. The device includes solar heating panels set into an A-shape, and enclosing an area therein containing a water tank and a wristatic fan that utilize the heat of the enclosed air, and transmit the thermal energy therefrom through a water line and an air line into the house.
Sykes, A.B.
Does the photon-diffusion coefficient depend on absorption?
and M. C. Edlund, The Elements of Nuclear Reactor Theory (Van Nostrand, New York, 1952), Chaps. 5 and 14 diffusion coefficient gives better agreement with theory than the traditionally accepted photon diffusion diffusion theory by using the two different diffu- sion coefficients, we quantitatively demonstrate
Boas, David
Field Measurement Studies on Shunt Coefficient of Lightning Shield Line
The shunt coefficient of lightning shield line is an important parameter, which needs to be considered when we are designing or reforming the substation grounding network, however, it is difficult to be calculated. This paper is to introduce a method ... Keywords: Short circuit current, Lightning shield line, Shunt coefficient, Shunt impedance
Dechao Li; Jinglu Li; Yuhuan Zhang
Calculation of fusion product angular correlation coefficients for fusion plasmas
The angular correlation coefficients for fusion products are calculated in the cases of Maxwellian and beam-target plasmas. Measurement of these coefficients as a localized ion temperature or fast-ion diagnostic is discussed. 8 refs., 7 figs., 1 tab.
Murphy, T.J.
Energy Basics: Heating Systems
of energy sources, including electricity, boilers, solar energy, and wood and pellet-fuel heating. Small Space Heaters Used when the main heating system is inadequate or when...
Total Space Heat-
Released: September, 2008 Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration Office Equip- ment Com- puters Other All Buildings...
Revised: December, 2008 Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration Office Equip- ment Com- puters Other All Buildings*...
Mass and Heat Recovery
In the last few years heat recovery was under spot and in air conditioning fields usually we use heat recovery by different types of heat exchangers. The heat exchanging between the exhaust air from the building with the fresh air to the building (air to air heat exchanger). In my papers I use (water to air heat exchanger) as a heat recovery and I use the water as a mass recovery. The source of mass and heat recovery is the condensate water which we were dispose and connect it to the drain lines.
Hindawai, S. M.
Energy Basics: Water Heating
Storage Water Heaters Tankless Demand Water Heaters Heat Pump Water Heaters Solar Water Heaters Tankless Coil & Indirect Water Heaters Water Heating A variety of...
Released: September, 2008 Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration Office Equip- ment Com- puters Other All Buildings*...
Revised: December, 2008 Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration Office Equip- ment Com- puters Other All Buildings...
Urban Heat Catastrophes
The curve shows the heat index, which reflects the combined effect of temperature and humidity. Last year's Chicago heat wave created a great deal of human discomfort and,...
Geothermal heat pump analysis article
heat pump transfers heat from the ground or ground water to provide space heating. In the summer, the heat transfer process is reversed; the ground or groundwater
ORISE: Dose Coefficients for Intakes of Radionuclides via Contaminated
Dose Coefficients for Intakes of Radionuclides via Contaminated Wounds Dose Coefficients for Intakes of Radionuclides via Contaminated Wounds Dose coefficients for 38 radionuclides based on NCRP Wound Model and ICRP biokinetic models This report is intended to assist health physics and medical staff in more rapidly assessing the potential dosimetric consequences of a contaminated wound. The National Council on Radiation Protection and Measurements Wound Model describing the retention of selected radionuclides at the site of a contaminated wound and their uptake into the transfer compartment has been combined with the International Commission on Radiological Protection element-specific systemic models for those radionuclides to derive dose coefficients for intakes via contaminated wounds. Examples are also provided on using the dose coefficients to generate derived reference
Fuzzy gain scheduling technique for power flow control
An application of fuzzy logic based control for power systems governing multiple Flexible Alternating Current Transmission System (FACTS) devices is described here. Sufficiently accurate relations have been derived to determine setpoints of FACTS ... Keywords: AC transmission, FACTS devices, Switzerland, flexible alternating current transmission system, fuzzy control, fuzzy gain scheduling, fuzzy logic, power flow control, power systems, sensitivity analysis
Alexandre Oudalov; Petr Korba; Rachid Cherkaoui; Alain J. Germond
Google's Loss: The Public's Gain APRIL 28, 2011
Google's Loss: The Public's Gain APRIL 28, 2011 Robert Darnton Musée du Louvre, Paris Jean a postmortem on Google's attempt to digitize and sell millions of books, despite the decision by Judge Denny Chin on March 23 to reject the agreement that seemed to make Google's project possible. Google Book
Hofri, Micha
Gain effect waveguide optical amplifiers for Si microphotonics
(cont.) Er-based gain. We reported the first infrared photoluminescence PL study of Er?O? and found a 7 ms lifetime at 4 K, attributed to a metastable FCC or HCP phase. We showed the thermodynamically stable BCC crystal ...
Saini, Sajan, 1973-
A methodology to assess the influence of local wind conditions and building orientation on the convective heat transfer at building surfaces
Information on the statistical mean convective heat transfer coefficient (CHTC"S"M) for a building surface, which represents the temporally-averaged CHTC over a long time span (e.g. the lifetime of the building), could be useful for example for the optimisation ... Keywords: Building facade, Building orientation, CFD, Convective heat transfer coefficient, Low-Reynolds number modelling, RANS, Wind climate
Thijs Defraeye; Jan Carmeliet
The design and operation of a calorimeter for use in the temperature range 1.8 to 4.2 deg K are presented, and the methods used in the treatment of data and calculation of results are discussed. The heat capacities of several Na- W bronzes (Na/sub x/WO/sub 3/) were determined in the temperature interval 1.8 to 4.2 deg K. Samples having x equal to 0.89, heat capacities are described adequately by the sum of two terms, one linear and one cubic in temperature. The electronic specific heat of each sample is obtained by evaluating the coefficient of the linear term, and the Rebye eharacteristic temperature derived from the coefficient of the cubic term. Rensities of one-electron energy levels at the Fermi energy, and effective electronic masses are calculated from the electronic specific heats. A plot of the density of states as a function of energy can be made if it is assumed that this curve is independent of Na concentration. The justification of this assumption is discussed in the light of current theories of the solid state. The density of states curve rises rapidly at higher energies, and this rise is interpreted in terms of the filling of a Brillouin zone or of an overlap of two bands. (auth)
Vest,R.W.; Griffel, M.; Smith, J.F.
Experimental study of mixed convection heat transfer in vertical helically coiled tube heat exchangers
In this study the mixed convection heat transfer in a coil-in-shell heat exchanger for various Reynolds numbers, various tube-to-coil diameter ratios and different dimensionless coil pitch was experimentally investigated. The experiments were conducted for both laminar and turbulent flow inside coil. Effects of coil pitch and tube diameters on shell-side heat transfer coefficient of the heat exchanger were studied. Different characteristic lengths were used in various Nusselt number calculations to determine which length best fits the data and several equations were proposed. The particular difference in this study in comparison with the other similar studies was the boundary conditions for the helical coils. The results indicate that the equivalent diameter of shell is the best characteristic length. (author)
Ghorbani, N. [School of Mechanical Engineering, University of Leeds, Leeds, England (United Kingdom); Taherian, H. [Department of Engineering Technology and Industrial Distribution, Texas A and M University, College Station, TX (United States); Gorji, M. [Department of Mechanical Engineering, Babol Noushirvani University of Technology, Babol (Iran); Mirgolbabaei, H. [Department of Mechanical Engineering, Islamic Azad University, Jouybar branch, Jouybar (Iran)
Solar-assisted heat pump system for cost-effective space heating and cooling
The use of heat pumps for the utilization of solar energy is studied. Two requirements for a cost-effective system are identified: (1) a special heat pump whose coefficient of performance continues to rise with source temperature over the entire range appropriate for solar assist, and (2) a low-cost collection and storage subsystem able to supply solar energy to the heat pump efficiently at low temperatures. Programs leading to the development of these components are discussed. A solar assisted heat pump system using these components is simulated via a computer, and the results of the simulation are used as the basis for a cost comparison of the proposed system with other solar and conventional systems.
Andrews, J W; Kush, E A; Metz, P D
Higher Fusion Power Gain with Current and Pressure Profile Control in Strongly Shaped DIII-D Tokamak Plasmas
Fusion power gain has been increased by a factor of 3 in DIII-D by tailoring the pressure profile to avoid the kink instability in {ital H}-mode plasmas. The resulting plasmas are found to have neoclassical ion confinement. This reduction in transport losses in beam-heated plasmas with negative central shear is correlated with a dramatic reduction in density fluctuations. Improved magnetohydrodynamic stability is achieved by controlling the plasma pressure profile width. In deuterium plasmas the highest gain {ital Q} (the ratio of fusion power to input power), was 0.0015, corresponding to an equivalent {ital Q} of 0.32 in a deuterium-tritium plasma. {copyright} {ital 1996 The American Physical Society.}
Lazarus, E.A.; Navratil, G.A.; Greenfield, C.M.; Strait, E.J.; Austin, M.E.; Burrell, K.H.; Casper, T.A.; Baker, D.R.; DeBoo, J.C.; Doyle, E.J.; Durst, R.; Ferron, J.R.; Forest, C.B.; Gohil, P.; Groebner, R.J.; Heidbrink, W.W.; Hong, R.; Houlberg, W.A.; Howald, A.W.; Hsieh, C.; Hyatt, A.W.; Jackson, G.L.; Kim, J.; Lao, L.L.; Lasnier, C.J.; Leonard, A.W.; Lohr, J.; La Haye, R.J.; Maingi, R.; Miller, R.L.; Murakami, M.; Osborne, T.H.; Perkins, L.J.; Petty, C.C.; Rettig, C.L.; Rhodes, T.L.; Rice, B.W.; Sabbagh, S.A.; Schissel, D.P.; Scoville, J.T.; Snider, R.T.; Staebler, G.M.; Stallard, B.W.; Stambaugh, R.D.; St. John, H.E.; Stockdale, R.E.; Taylor, P.L.; Thomas, D.M.; Turnbull, A.D.; Wade, M.R.; Wood, R.; Whyte, D. [General Atomics, P.O. Box 85608, San Diego, California 92186-9784 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186-9784 (United States)
Radiative Heat Transfer between Neighboring Particles
The near-field interaction between two neighboring particles is known to produce enhanced radiative heat transfer. We advance in the understanding of this phenomenon by including the full electromagnetic particle response, heat exchange with the environment, and important radiative corrections both in the distance dependence of the fields and in the particle absorption coefficients. We find that crossed terms of electric and magnetic interactions dominate the transfer rate between gold and SiC particles, whereas radiative corrections reduce it by several orders of magnitude even at small separations. Radiation away from the dimer can be strongly suppressed or enhanced at low and high temperatures, respectively. These effects must be taken into account for an accurate description of radiative heat transfer in nanostructured environments.
Alejandro Manjavacas; F. Javier Garcia de Abajo
Rotary magnetic heat pump
A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.
Kirol, Lance D. (Shelly, ID)
Direct fired heat exchanger
A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.
Reimann, Robert C. (Lafayette, NY); Root, Richard A. (Spokane, WA)
In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.
Piscitella, Roger R. (Idaho Falls, ID)
A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.
Kirol, L.D.
Geothermal heat pump grouting materials
The thermal conductivity of cementitious grouts has been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. The cement-sand grouts were also tested for rheological characteristics, bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the thermal conductivity, permeability, bonding and exotherm data for selected cementitious grouts. The theoretical reduction in bore length that could be achieved with the BNL-developed cement-sand grouts is examined. Finally, the FY 98 research and field trials are discussed.
Allan, M.
The Annual March of the Heat Budget of the North and Tropical Atlantic Oceans
This paper documents the annual march of the following processes for the 70�N�20�S region of the Atlantic, including the Gulf of Mexico and Caribbean Sea: net surface heat gains (monthly mean time-scale), subsurface heat storage change (bimonthly)...
Peter J. Lamb; Andrew F. Bunker
Thulium-170 heat source
An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.
Walter, Carl E. (Pleasanton, CA); Van Konynenburg, Richard (Livermore, CA); VanSant, James H. (Tracy, CA)
Walter, C.E.; Van Konynenburg, R.; VanSant, J.H.
Heat pump/refrigerator using liquid working fluid
A heat transfer device is described that can be operated as a heat pump or refrigerator, which utilizes a working fluid that is continuously in a liquid state and which has a high temperature-coefficient of expansion near room temperature, to provide a compact and high efficiency heat transfer device for relatively small temperature differences as are encountered in heating or cooling rooms or the like. The heat transfer device includes a pair of heat exchangers that may be coupled respectively to the outdoor and indoor environments, a regenerator connecting the two heat exchangers, a displacer that can move the liquid working fluid through the heat exchangers via the regenerator, and a means for alternately increasing and decreasing the pressure of the working fluid. The liquid working fluid enables efficient heat transfer in a compact unit, and leads to an explosion-proof smooth and quiet machine characteristic of hydraulics. The device enables efficient heat transfer as the indoor-outdoor temperature difference approaches zero, and enables simple conversion from heat pumping to refrigeration as by merely reversing the direction of a motor that powers the device.
Wheatley, John C. (Del Mar, CA); Paulson, Douglas N. (Del Mar, CA); Allen, Paul C. (Solana Beach, CA); Knight, William R. (Corvallis, OR); Warkentin, Paul A. (San Diego, CA)
The Green's Function of the Supersymmetric D=1 Heat Equation
A rigorous treatment is given of the Green's function of the N=1 supersymmetric heat equation in one spatial dimension with a distribution initial value. The asymptotic expansion of the supersymmetric Green's function as t tends to 0+ is also derived. The coefficients of the expansion generate all the members of the supersymmetric N=1 KdV hierarchy.
S. Andrea; A. Restuccia; A. Sotomayor
Transport coefficients of n-butane into and through the surface of silicalite-1 from non-equilibrium molecular dynamics study
Transport coefficients of n-butane into and through the surface of silicalite-1 from non dynamics Non-equilibrium thermodynamics Silicalite-1 n-Butane adsorption a b s t r a c t We have studied coupled heat and mass transfer of n-butane through a membrane of silicalite-1. A description
Kjelstrup, Signe
Heat pipe system
A heat pipe diode device for transferring heat from a heat source component to a heat sink wall is described. It contains a heat pipe body member attached to the best source; the heat source having a wall forming at least a portion of the normal evaporator section of the heat pipe diode; a working fluid within the body member; a cover for the heat pipe diode forming at least a portion of the heat sink wall; the cover forming the normal condenser for the heat pipe diode; a wick connected between the condenser and the evaporator of the heat pipe diode; means for retaining the wick adjacent the heat pipe wall; a wick support plate adjacent to the cover; the wick being attached to the support plate; means for holding the wick in contact with the cover; and means, responsive to excessive temperatures at the heat sink wall, for moving the support plate and a portion of the wick away from the cover to thereby substantially reduce heat flow in the reverse direction through said heat pipe diode device.
Kroebig, H.L.; Riha, F.J. III
Application of small-signal fusion energy gain
The measured burnup fraction of the 1-MeV tritons produced in a deuterium tokamak plasma, multiplied by 17.5, is essentially the small-signal fusion energy gain g/sub T/ for an ideal 1-MeV triton beam injected into the deuterium plasma. The measured g/sub T/ can be converted directly into the two-component fusion energy gain that would be realized if a lower energy tritium beam were injected into the plasma, or if a deuterium beam were injected into a tritium target plasma having the same parameters as the acutal deuterium plasma. Under certain conditions, g/sub T/ greater than or equal to 1 can be obtained by injection of a low-current 225-keV tritium beam into a hot deuterium plasma, thereby verifying that the plasma has the essential characteristics needed for achieving macroscopic fusion energy ''break-even.''
Jassby, D.L.
Stability in High Gain Plasmas in DIII-D
Fusion power gain has been increased by a factor of 3 in DIII-D plasmas through the use of strong discharge shaping and tailoring of the pressure and current density profiles. H-mode plasmas with weak or negative central magnetic shear are found to have neoclassical ion confinement throughout most of the plasma volume. Improved MHD stability is achieved by controlling the plasma pressure profile width. The highest fusion power gain Q (ratio of fusion power to input power) in deuterium plasmas was 0.0015. which extrapolates to an equivalent Q of 0.32 in a deuterium-tritium plasma and is similar to values achieved in tokamaks of larger size and magnetic fields.
Lazarus, E. A.; Hong, R. M. [Oak Ridge National Lab., TN (United States); Navratil, G. A.; Sabbagh, S. [Columbia Univ., New York, NY (United States); Strait, E. J.; Rice, B. W. [Lawrence Livermore National Lab., CA (United States); Ferron, J. R.; Greenfield, C. M.; Austin, M. E. [Maryland Univ., College Park, MD (United States); Chan, V. S.; DeBoo, J. C.; Doyle, E. J. [California Univ., Los Angeles, CA (United States; Durst, R. [Wisconsin Univ., Madison, WI (United States); Forest, C. B. [California Univ., Irvine, CA (United States); Leonard, A. W. [Oak Ridge Associated Universities, Inc., TN (United States); Schissel, D. P. [JET Joint Undertaking, Abingdon (United Kingdom)
Wind Stress Drag Coefficient over the Global Ocean
Interannual and climatological variations of wind stress drag coefficient (CD) are examined over the global ocean from 1998 to 2004. Here CD is calculated using high temporal resolution (3- and 6-hourly) surface atmospheric variables from two ...
A. Birol Kara; Alan J. Wallcraft; E. Joseph Metzger; Harley E. Hurlburt; Chris W. Fairall
Skill Scores and Correlation Coefficients in Model Verification
Attributes of the anomaly correlation coefficient, as a model verification measure, are investigated by exploiting a recently developed method of decomposing skill scores into other measures of performance. A mean square error skill score based ...
Allan H. Murphy; Edward S. Epstein
On Lateral Dispersion Coefficients as Functions of Averaging Time
Plume dispersion coefficients are discussed in terms of single-particle and relative diffusion, and are investigated as functions of averaging time. To demonstrate the effects of averaging time on the relative importance of various dispersion ...
C. M. Sheih
Asymptotic Properties of an Autocorrelation Coefficient for Coherent Doppler Sonar
A new formula is derived for the asymptotic form of the magnitude of an autocorrelation coefficient for coherent Doppler sonar. The autocorrelation magnitude is shown to be a biased estimator in the limit of infinite ensemble length. Numerical ...
Jeremy Dillon; Len Zedel; Alex E. Hay
Some comments on `Equation for the second virial coefficient`
The second viral coefficient calculated using the equation suggested in the paper of Kaplun A.B., Meshalkin A.B. Equation for the second virial coefficient published in High temperature high pressure, 1999, Volume 31, pages 253-258 is compared with experimental data for helium, hydrogen, neon, argon, krypton, xenon, carbon dioxide, water, ammonia, methane, ethylene. It is shown the formula cannot describe the temperature dependence of the experimental data on the second virial coefficient for the all above substances within the experimental error over the investigated temperature interval. The latter is in controversy with the derivations of the paper mentioned above. It is also shown the formula cannot describe the recommended data for the second virial coefficient within their uncertainties for helium, hydrogen, neon, argon, krypton and methane.
Umirzakov, I H
A simple estimator for the distribution of random coefficients
We propose a simple mixtures estimator for recovering the joint distribution of parameter heterogeneity in economic models, such as the random coefficients logit. The estimator is based on linear regression subject to ...
Ryan, Stephen
Wavelength Dependence of Aerosol Extinction Coefficient for Stratospheric Aerosols
A simple empirical formula for the wavelength dependence of the aerosol extinction coefficient is proposed. The relationship between the constants in the formula and the variable parameter in the aerosol size distribution is explicitly expressed. ...
Glenn K. Yue
Wind Gains ground, hitting 33 GW of installed capacity
The U.S. currently has 33 GW of installed wind capacity. Wind continues to gain ground, accounting for 42 percent of new capacity additions in the US in 2008.Globally, there are now 146 GW of wind capacity with an impressive and sustained growth trajectory that promises to dominate new generation capacities in many developing countries. The U.S., however, lags many European countries, with wind providing roughly 2 percent of electricity generation.
but by a heat source such as natural gas, propane, solar-heated water, or geothermal-heated water. Because natural gas is the most common heat source for absorption heat...
Gain Scheduled Control Using the Dual Youla Parameterization
Stability is a critical issue in gain-scheduled control problems in that the closed loop system may not be stable during the transitions between operating conditions despite guarantees that the gain-scheduled controller stabilizes the plant model at fixed values of the scheduling variable. For Linear Parameter Varying (LPV) model representations, a controller interpolation method using Youla parameterization that guarantees stability despite fast transitions in scheduling variables is proposed. By interconnecting an LPV plant model with a Local Controller Network (LCN), the proposed Youla parameterization based controller interpolation method allows the interpolation of controllers of different size and structure, and guarantees stability at fixed points over the entire operating region. Moreover, quadratic stability despite fast scheduling is also guaranteed by construction of a common Lyapunov function, while the characteristics of individual controllers designed a priori at fixed operating condition are recovered at the design points. The efficacy of the proposed approach is verified with both an illustrative simulation case study on variation of a classical MIMO control problem and an experimental implementation on a multi-evaporator vapor compression cycle system. The dynamics of vapor compression systems are highly nonlinear, thus the gain-scheduled control is the potential to achieve the desired stability and performance of the system. The proposed controller interpolation/switching method guarantees the nonlinear stability of the closed loop system during the arbitrarily fast transition and achieves the desired performance to subsequently improve thermal efficiency of the vapor compression system.
Chang, Young Joon
Generalized Levinson-Durbin sequences, binomial coefficients and autoregressive estimation
For a discrete time second-order stationary process, the Levinson-Durbin recursion is used to determine the coefficients of the best linear predictor of the observation at time k+1, given k previous observations, best in the sense of minimizing the mean ... Keywords: 05A10, 11B65, 62M10, Binomial coefficients, Generalized Levinson-Durbin sequence, Least squares estimator, Levinson-Durbin sequence, Partial correlations, Yule-Walker estimator
Paul Shaman
Energy Basics: Air-Source Heat Pumps
Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for Concentrating Solar Power Plants
A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing the commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during experimentation.
Mathur, Anoop [Terrafore Inc.] [Terrafore Inc.
Physical model for the latent heat of fusion
The atomic movement induced on melting has to overcome a viscous drag resistance. It is suggested that the latent heat of fusion supplies the required energy for this physical process. The viscosity model introduced here allows computation of the latent heat from viscosity, molar volume, melting temperature, and atomic mass and diameter. The correlation between these parameters and the latent heat of 14 elements with body and face centered cubic structures was exceptional, with the correlation coefficients of 0.97 and 0.95 respectively.
Modelling of heat transfer at glass/mould interface in press and blow forming processes
Numerical models may play an important role in the optimization of the quality of hollow-ware glass articles in glass industry. Due to the complexity of the phenomena involved a coupling between thermal and mechanical aspects is crucial. One of the key ... Keywords: Finite elements, Glass forming, Heat conduction, Heat transfer coefficient, Interface element, Press/blow process
S�bastien Gr�goire; Jos� M. A. C�sar de S�; Philippe Moreau; Dominique Lochegnies
Latent heat accumulating greenhouse
This invention relates to a latent heat accumulating greenhouse utilizing solar heat. The object of the invention is to provide a greenhouse which is simple in construction, of high efficiency for heat absorbing and capable of much absorbing and accumulating of heat. A heat accumulating chamber partitioned by transparent sheets is provided between the attic and a floor surface facing north in the greenhouse. A blower fan is disposed to confront an opening provided at the lower portion in said heat accumulating chamber. Also, in the heat accumulating chamber, a heat accumulating unit having a large number of light transmitting windows and enclosing a phase transformation heat accumulating material such as CaC1/sub 2/.6H/sub 2/O, Na/sub 2/SO/sub 4/.10H/sub 2/O therein is detachably suspended in a position close to windowpanes at the north side.
Yano, N.; Ito, H.; Makido, I.
Waste Heat Doesn't Have to be a Waste of Money- The American & Efird Heat Recovery Project: A First for the Textile Industry
In 1989 American & Efird, Inc., decided to upgrade their heat recovery system at its Dyeing & Finishing Plant in Mt. Holly, North Carolina. They chose an electric industrial process heat pump to enhance heat recovery and to lower operating costs. This application of the industrial process heat pump was the first of its kind in the American textile industry and was the result of a three year cooperative effort between American & Efird, Inc. and Duke Power Company. This innovative application of heat pump technology has allowed American & Efird to gain additional boiler capacity, lower waste water discharge temperatures and achieve significant energy savings. Duke Power will gain an additional 572,000 KWH in annual sales, of which approximately 70 percent will occur during off-peak hours, and American & Efird will enjoy lower overall energy costs.
Smith, S. W.
Heat transfer system
A heat transfer system for a nuclear reactor. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.
McGuire, Joseph C. (Richland, WA)
Laundry heat recovery system
A laundry heat recovery system includes a heat exchanger associated with each dryer in the system, the heat exchanger being positioned within the exhaust system of the dryer. A controller responsive to the water temperature of the heat exchangers and the water storage for the washer selectively circulates the water through a closed loop system whereby the water within the exchangers is preheated by the associated dryers. By venting the exhaust air through the heat exchanger, the air is dehumidified to permit recirculation of the heated air into the dryer.
Alio, P.
Wound tube heat exchanger
What is disclosed is a wound tube heat exchanger in which a plurality of tubes having flattened areas are held contiguous adjacent flattened areas of tubes by a plurality of windings to give a double walled heat exchanger. The plurality of windings serve as a plurality of effective force vectors holding the conduits contiguous heat conducting walls of another conduit and result in highly efficient heat transfer. The resulting heat exchange bundle is economical and can be coiled into the desired shape. Also disclosed are specific embodiments such as the one in which the tubes are expanded against their windings after being coiled to insure highly efficient heat transfer.
A heat transfer system for a nuclear reactor is described. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.
Enhanced boiling heat transfer in horizontal test bundles
Two-phase flow boiling from bundles of horizontal tubes with smooth and enhanced surfaces has been investigated. Experiments were conducted in pure refrigerant R-113, pure R-11, and mixtures of R-11 and R-113 of approximately 25, 50, and 75% of R-113 by mass. Tests were conducted in two staggered tube bundles consisting of fifteen rows and five columns laid out in equilateral triangular arrays with pitch-to-diameter ratios of 1.17 and 1.5. The enhanced surfaces tested included a knurled surface (Wolverine`s Turbo-B) and a porous surface (Linde`s High Flux). Pool boiling tests were conducted for each surface so that reference values of the heat transfer coefficient could be obtained. Boiling heat transfer experiments in the tube bundles were conducted at pressures of 2 and 6 bar, heat flux values from 5 to 80 kW/m{sup 2}s, and qualities from 0% to 80%, Values of the heat transfer coefficients for the enhanced surfaces were significantly larger than for the smooth tubes and were comparable to the values obtained in pool boiling. It was found that the performance of the enhanced tubes could be predicted using the pool boiling results. The degradation in the smooth tube heat transfer coefficients obtained in fluid mixtures was found to depend on the difference between the molar concentration in the liquid and vapor.
Trewin, R.R.; Jensen, M.K.; Bergles, A.E.
Heat Exchangers for Solar Water Heating Systems | Department of Energy
Heat Exchangers for Solar Water Heating Systems Heat Exchangers for Solar Water Heating Systems Heat Exchangers for Solar Water Heating Systems May 30, 2012 - 3:40pm Addthis Image of a heat exchanger. | Photo from iStockphoto.com Image of a heat exchanger. | Photo from iStockphoto.com Solar water heating systems use heat exchangers to transfer solar energy absorbed in solar collectors to the liquid or air used to heat water or a space. Heat exchangers can be made of steel, copper, bronze, stainless steel, aluminum, or cast iron. Solar heating systems usually use copper, because it is a good thermal conductor and has greater resistance to corrosion. Types of Heat Exchangers Solar water heating systems use three types of heat exchangers: Liquid-to-liquid A liquid-to-liquid heat exchanger uses a heat-transfer fluid that
Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results
A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.
O'Brien, James Edward; Sohal, Manohar Singh; Huff, George Albert
Condensing Heat Exchanger for Optimization of Energy Efficiency
Historically, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense out, rapid deterioration, due to acid corrosion, of the outlet duct and stack would result. With the development of the condensing heat exchanger, boiler efficiency can now exceed 90%. Approximately 1% gain in boiler efficiency can be expected for every 40F (4.5C) reduction in flue gas stack temperature. In the CHX� condensing heat exchanger, all gas wetted surfaces are covered with DuPont Teflon�. The Teflon covered heat exchanger surfaces are impervious to all acids normally resulting from the combustion of fossil fuels. This allows the flue gas to be cooled to below the water vapor dew point with no subsequent corrosion of the heat exchanger surfaces.
Carrigan, J. F.; Johnson, D. W.; DiVitto, J. G.; Schulze, K. H.
Heat storage in alloy transformations. Final report
A study conducted to determine the feasibility of using metal alloys as thermal energy storage media is described. The study had the following major elements: (1) the identification of congruently transforming alloys and thermochemical property measurements, (2) the development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients, (3) the development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase-change materials, and (4) the identification of materials that could be used to contain the metal alloys. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases have been determined. A new method employing x-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data that are obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase-change media. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide has been identified as a promising containment material and surface-coated iron alloys were considered.
Birchenall, C E; Gueceri, S I; Farkas, D; Labdon, M B; Nagaswami, N; Pregger, B
Radial wave thermoacoustic engines: Theory and examples for refrigerators and high?gain narrow?bandwidth photoacoustic spectrometers
A theoretical analysis of radial wave thermoacoustic engines in cylindrical resonators is developed. Impedance and pressure translation equations are presented for open sections of the resonator and for heat exchangers. Coupled first?order differential equations are given for pressure and impedance in the temperature gradient supporting engine section (stack). These quantities are used to calculate heat and work flows and to predict engine performance. Theory and design of a variable quality factor resonator for enhanced photoacoustic spectroscopy are presented. The short stack approximation is developed for the radial geometry and is used along with plane?wave equations to compare refrigerator performance for these two geometries. Results of the comparison are that engines in the plane?wave geometry are better overall refrigerators when maximizing the coefficient of performance and cooling capacity together.
W. Patrick Arnott; Richard Raspet; Hans Moosm�ller
CLOSED-FORM INTEGRAL SOLUTIONS FOR LINEAR HEAT CONDUCTION.For linear heat conduction in a homogeneous, isotropiclaw of similitude for linear heat conduction was utilized to
Chan, T.
Consolidated Electric Cooperative- Heat Pump and Water Heating Rebates
Consolidated Electric Cooperative provides rebates to residential customers who install electric water heaters, dual-fuel heating system or geothermal heat pumps. A dual-fuel heating systems...
Analysis of. Nonlinear Heat Transfer Problems." Report no.Berkeley, Ca. , APPENDIX A. HEAT TRANSFER BY CONDUCTION ANDMeeting, Technical Session on Heat Transfer in Nuclear Waste
Section D: SPACE HEATING
Central warm-air furnace with ducts to individual rooms other than a heat pump ..... 03 Steam/Hot water ... REVERSE Heat pump ... Don't have a separate water heater ...
Survey: Energy End-Use Consumption Tables Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration Office Equip- ment Com- puters Other...
Heat pipe fabrication
A heat pipe is disclosed which is fabricated with an artery arranged so that the warp and weave of the wire mesh are at about a 45/sup 0/ angle with respect to the axis of the heat pipe.
Leinoff, S.; Edelstein, F.; Combs, W.
Electric Resistance Heating
Electric resistance heat can be supplied by centralized forced-air electric furnaces or by heaters in each room. Electric resistance heating converts nearly all of the energy in the electricity to...
Space Heating and Cooling
A wide variety of technologies are available for heating and cooling homes and other buildings. In addition, many heating and cooling systems have certain supporting equipment in common, such as...
Fine Adjustment of Large Scale Air-Sea Energy Flux Parameterizations by Direct Estimates of Ocean Heat Transport
An inverse technique is used to adjust uncertain coefficients and parameters in the bulk formulae of climatological air-sea energy fluxes in order to obtain an agreement of indirect estimates of meridional heat transport with direct estimates in ...
Hans-J�rg Isemer; J�rgen Willebrand; Lutz Hasse
Heating surface material�s effect on subcooled flow boiling heat transfer of R134a
In this study, subcooled flow boiling of R134a on copper (Cu) and stainless steel (SS) heating surfaces was experimentally investigated from both macroscopic and microscopic points of view. By utilizing a high-speed digital camera, bubble growth rate, bubble departure size, and nucleation site density, were able to be observed and analyzed from the microscopic point of view. Macroscopic characteristics of the subcooled flow boiling, such as heat transfer coefficient, were able to be measured as well. Experimental results showed that there are no obvious difference between the copper and the stainless surface with respect to bubble dynamics, such as contact angle, growth rate and departure size. On the contrary, the results clearly showed a trend that the copper surface had a better performance than the stainless steel surface in terms of heat transfer coefficient. It was also observed that wall heat fluxes on both surfaces were found highly correlated with nucleation site density, as bubble hydrodynamics are similar on these two surfaces. The difference between these two surfaces was concluded as results of different surface thermal conductivities.
Ling Zou; Barclay G. Jones
Microchannel crossflow fluid heat exchanger and method for its fabrication
A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance.
Swift, Gregory W. (Los Alamos, NM); Migliori, Albert (Santa Fe, NM); Wheatley, John C. (Los Alamos, NM)
Swift, G.W.; Migliori, A.; Wheatley, J.C.
A microchannel crossflow fluid heat exchanger and a method for its fabrication are disclosed. The heat exchanger is formed from a stack of thin metal sheets which are bonded together. The stack consists of alternating slotted and unslotted sheets. Each of the slotted sheets includes multiple parallel slots which form fluid flow channels when sandwiched between the unslotted sheets. Successive slotted sheets in the stack are rotated ninety degrees with respect to one another so as to form two sets of orthogonally extending fluid flow channels which are arranged in a crossflow configuration. The heat exchanger has a high surface to volume ratio, a small dead volume, a high heat transfer coefficient, and is suitable for use with fluids under high pressures. The heat exchanger has particular application in a Stirling engine that utilizes a liquid as the working substance. 9 figs.
The role of asymmetric inter-particle interactions in heat conduction
We numerically calculate the heat conductivity by using the Green-Kubo formula to confirm that asymmetric inter-particle interactions in one-dimensional momentum conserving lattices can induce normal heat conduction. The Lennard-Jones (L-J) inter-particle interactions are focused in view of their practical significance. The effects of the asymmetric inter-particle interactions on the cross-correlation coefficient between the heat and mass fluxes are also discussed.
Chen, Shunda; Wang, Jiao; Zhao, Hong
Solar heat receiver
A receiver for converting solar energy to heat a gas to temperatures from 700.degree.-900.degree. C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.
Hunt, Arlon J. (Oakland, CA); Hansen, Leif J. (Berkeley, CA); Evans, David B. (Orinda, CA)
A receiver is described for converting solar energy to heat a gas to temperatures from 700 to 900/sup 0/C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.
Hunt, A.J.; Hansen, L.J.; Evans, D.B.
Abrasion resistant heat pipe
A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.
Ernst, Donald M. (Leola, PA)
A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.
Ernst, D.M.
Flue heat reclaimer
A flue heat reclaimer is constructed to be mounted on the exterior of a flue duct of a heater and provide a spiral-shaped heat transfer passage extending around the flue duct. A fan causes air to flow through the heat transfer passage so that the temperature of this air is elevated by reason at its extended heat transfer relationship with the flue duct.
Paolino, R.J.
Using Quantum Coherence to Enhance Gain in Atomic Physics
Quantum coherence and interference effects in atomic and molecular physics has been extensively studied due to intriguing counterintuitive physics and potential important applications. Here we present one such application of using quantum coherence to generate and enhance gain in extreme ultra-violet(XUV)(@58.4nm in Helium) and infra-red(@794.76nm in Rubidium) regime of electromagnetic radiation. We show that using moderate external coherent drive, a substantial enhancement in the energy of the lasing pulse can be achieved under optimal conditions. We also discuss the role of coherence. The present paper is intended to be pedagogical on this subject of coherence-enhanced lasing.
Pankaj K. Jha
We present experimental studies of the gain length and saturation power level from 1.5 nm to 1.5 Angstroms at the Linac Coherent Light Source (LCLS). By disrupting theFEL process with an orbit kick, we are able to measure the X-ray intensity as a function of undulator length. This kick method is cross-checked with the method of removing undulator sections. We also study the FEL-induced electron energy loss after saturation to determine the optimal taper of the undulator K values. The experimental results are compared to theory and simulations.
Ratner, D.; Fawley, W. M.; Brachmann, A.; Decker, F.J.; Ding, Y.; Dowell, D.; Emma, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, P.; Huang, Z.; Loos, H.; Miahnahri, A.; Nuhn, H.D.; Turner, J.; Welch, J.; White, W.; Wu, J.; Xiang, D.; Yocky, G.; Fawley, W. M.
High resolution BPMS with integrated gain correction system
High resolution beam position monitors (BPM) are an essential tool to achieve and reproduce a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring. The ATF damping ring (DR) BPMs are currently upgraded with new high resolution read-out electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducible beam position readings. The concept and its technical realization, as well as preliminary results of beam studies are presented.
Wendt, M.; Briegel, C.; Eddy, N.; Fellenz, B.; Gianfelice, E.; Prieto, P.; Rechenmacher, R.; Voy, D.; /Fermilab; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba
Diffusion coefficients in trimethyleneoxide containing comb branch polymer
Diffusion coefficients in trimethyleneoxide containing comb branch polymer Diffusion coefficients in trimethyleneoxide containing comb branch polymer electrolytes Title Diffusion coefficients in trimethyleneoxide containing comb branch polymer electrolytes Publication Type Journal Article Year of Publication 2004 Authors Liu, Gao, Craig L. Reeder, Xiaoguang Sun, and John B. Kerr Journal Solid State Ionics Volume 175 Pagination 781-783 Keywords comb branch polyethers, conductivity, lithium battery, polymer electrolytes, salt diffusion coefficient, trimethylene oxide Abstract This paper reports on a new comb branch polymer based on trimethylene oxide (TMO) side chains as a polymer electrolyte for potential application in lithium metal rechargeable batteries. The trimethylene oxide (TMO) units are attached to the side chains of a polyepoxide ether to maximize the segmental motion. Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) salt was used to formulate the polymer electrolyte with the new TMO containing polymers. The new polymer electrolytes show improved salt diffusion coefficients (Ds) and conductivity at ambient and subambient temperature compare to the ethylene oxide (EO) counterpart, whereas performance at high temperature (85 °C) remains the same or is actually worse for salt diffusivity.
A heat exchanger is adapted to unifomly cool a spherical surface. Equations for the design of a spherical heat exchanger hav~g tubes with a uniform center-to-center spining are given. The heat exchanger is illustrated in connection with a liquid-fueled reactor.
Fraas, A.P.; Wislicenus, G.F.
A corrosive resistant heat exchanger
A corrosive and erosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is pumped through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium. 3 figs., 3 tabs.
Richlen, S.L.
EERE: Energy Basics Geothermal Heat Pumps Geothermal heat pumps use the constant temperature of the earth as an exchange medium for heat. Although many parts of the country...
Anomaly induced transport coefficients, from weak to strong coupling
The existence of new transport phenomena associated to the presence of quantum anomalies has atracted very recently the attention of theorist. These transport coefficient have very interesting properties, for example, they do not renormalize. The most famous case of anomaly induced transport phenomena is the Chiral Magnetic Effect, in which an electric current is produced by a magnetic field if the system has a different number of right handed fermions respect the left handed one. In this thesis we have studied those transport coefficients from Kubo formulas at weak and strong coupling. To finish a fluid/gravity approach is used to compute all the second order anomalous coefficients in an anomalous conformal fluid.
Francisco Pena-Benitez
Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients
In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.
Kheder, G; Massoued, M Ben; Samet, M
Chemical heat pump
A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer. The heat pump part of the system heats or cools a house or other structure through a combination of evaporation and absorption or, conversely, condensation and desorption, in a pair of containers. A set of automatic controls change the system for operation during winter and summer months and for daytime and nighttime operation to satisfactorily heat and cool a house during an entire year. The absorber chamber is subjected to solar heating during regeneration cycles and is covered by one or more layers of glass or other transparent material. Daytime home air used for heating the home is passed at appropriate flow rates between the absorber container and the first transparent cover layer in heat transfer relationship in a manner that greatly reduce eddies and resultant heat loss from the absorbant surface to ambient atmosphere.
Greiner, Leonard (2750-C Segerstrom Ave., Santa Ana, CA 92704)
Transport coefficients from the Nambu-Jona-Lasinio model for $SU(3)_f$
We calculate the shear $\\eta(T)$ and bulk viscosities $\\zeta(T)$ as well as the electric conductivity $\\sigma_e(T)$ and heat conductivity $\\kappa(T)$ within the Nambu-Jona-Lasinio model for 3 flavors as a function of temperature as well as the entropy density $s(T)$, pressure $P(T)$ and speed of sound squared $c_s^2(T)$. We compare the results with other models such as the Polyakov-Nambu-Jona-Lasinio (PNJL) model and the dynamical quasiparticle model (DQPM) and confront these results with lattice QCD data whenever available. We find the NJL model to have a limited predictive power for the thermodynamic variables and various transport coefficients above the critical temperature whereas the PNJL model and DQPM show acceptable results for the quantities of interest.
Rudy Marty; Elena Bratkovskaya; Wolfgang Cassing; J�rg Aichelin; Hamza Berrehrah
We calculate the shear $\\eta(T)$ and bulk viscosities $\\zeta(T)$ as well as the electric conductivity $\\sigma_e(T)$ and heat conductivity $\\kappa(T)$ within the Nambu-Jona-Lasinio model for 3 flavors as a function of temperature as well as the entropy density $s(T)$, pressure $P(T)$ and speed of sound $c_s^2(T)$. We compare the results with other models such as the Polyakov-Nambu-Jona-Lasinio (PNJL) model and the dynamical quasiparticle model (DQPM) and confront these results with lattice QCD data whenever available. We find the NJL model to have a limited predictive power for the thermodynamic variables and various transport coefficients above the critical temperature whereas the PNJL model and DQPM show acceptable results for the quantities of interest.
Heat conduction in relativistic neutral gases revisited
The kinetic theory of dilute gases to first order in the gradients yields linear relations between forces and fluxes. The heat flux for the relativistic gas has been shown to be related not only to the temperature gradient but also to the density gradient in the representation where number density, temperature and hydrodynamic velocity are the independent state variables. In this work we show the calculation of the corresponding transport coefficients from the full Boltzmann equation and compare the magnitude of the relativistic correction.
A. L. Garcia-Perciante; A. R. Mendez
An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.
Grossman, Gershon (Oak Ridge, TN); Perez-Blanco, Horacio (Knoxville, TN)
Applied heat transfer
Heat transfer principles are discussed with emphasis on the practical aspects of the problems. Correlations for heat transfer and pressure drop from several worldwide sources for flow inside and outside of tubes, including finned tubes are presented, along with design and performance calculations of heat exchangers economizers, air heaters, condensers, waste-heat boilers, fired heaters, superheaters, and boiler furnaces. Vibration analysis for tube bundles and heat exchangers are also discussed, as are estimating gas-mixture properties at atmospheric and elevated pressures and life-cycle costing techniques. (JMT)
Ganapathy, V.
law of similitude for linear heat conduction was utilized tothe analogy between heat conduction and fluid flow in por�the effects of heat conduction through the vermiculite heat
Measurement and quantification of aggregate thermal coefficient of expansion
The coefficient of thermal expansion of concrete affects thermal related distresses in pavements. Factors affecting expansion of concrete and aggregates along with existing models are reviewed. A test method to measure the coefficient of thermal expansion of aggregates is proposed. Existing methods used to analyze oxide contents are evaluated. A relation between the oxide content of various elements in aggregates and the CTE of aggregate is presented. Results obtained from the proposed method are presented. A model is also presented for the CTE of concrete based on aggregate properties.
Chande, Gautam U
RECOMBINATION RATE COEFFICIENTS OF Be-LIKE Si
Recombination of Be-like Si{sup 10+} over the 0-43 eV electron-ion energy range is measured at the CRYRING electron cooler. In addition to radiative and dielectronic recombination, the recombination spectrum also shows strong contributions from trielectronic recombination. Below 100 meV, several very strong resonances associated with a spin-flip of the excited electron dominate the spectrum and also dominate the recombination in the photoionized plasma. The resonant plasma rate coefficients corrected for the experimental field ionization are in good agreement with calculated results by Gu and with AUTOSTRUCTURE calculations. All other calculations significantly underestimate the plasma rate coefficients at low temperatures.
Orban, I.; Boehm, S.; Schuch, R. [Department of Physics, Stockholm University, 10691 Stockholm (Sweden); Loch, S. D. [Department of Physics, Auburn University, Auburn, AL 36849 (United States)
Exergy Analysis and Operational Efficiency of a Horizontal Ground Source Heat Pump System Operated in a Low-Energy Test House under Simulated Occupancy Conditions
This paper presents data, analyses, measures of performance, and conclusions for a ground-source heat pump (GSHP) providing space conditioning to a 345m2 house whose envelope is made of structural insulated panels (SIP). The entire thermal load of this SIP house with RSI-3.7 (RUS-21) walls, triple pane windows with a U-factor of 1.64 W/m2 K (0.29 Btu/h ft2 oF) and solar heat gain coefficient (SHGC) of 0.25, a roof assembly with overall thermal resistance of about RSI-8.8 (RUS-50) and low leakage rates of 0.74 ACH at 50Pa was satisfied with a 2.16-Ton (7.56 kW) GSHP unit consuming negligible (9.83kWh) auxiliary heat during peak winter season. The highest and lowest heating COP achieved was 4.90 (October) and 3.44 (February), respectively. The highest and lowest cooling COP achieved was 6.09 (April) and 3.88 (August). These COPs are calculated on the basis of the total power input (including duct, ground loop, and control power losses ). The second Law (Exergy) analysis provides deep insight into how systemic inefficiencies are distributed among the various GSHP components. Opportunities for design and further performance improvements are identified. Through Exergy analysis we provide a true measure of how closely actual performance approaches the ideal, and it unequivocally identifies, better than energy analysis does, the sources and causes of lost work, the root cause of system inefficiencies.
Ally, Moonis Raza [ORNL; Baxter, Van D [ORNL; Munk, Jeffrey D [ORNL; Gehl, Anthony C [ORNL
Plasma heat pump and heat engine
A model system where cold charged particles are locally confined in a volume V{sub P} within a warm plasma of volume V (V{sub P}kilowatts is possible with the present day technology. Second, we discuss the feasibility of constructing an electrostatic heat engine which converts plasma heat into mechanical work via plasma electric fields. Effects of P{sub E} are shown to be observable in colloidal solutions.
Avinash, K. [Centre for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, Alabama 35899 (United States) and Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)
Heat pump apparatus
A heat pump apparatus including a compact arrangement of individual tubular reactors containing hydride-dehydride beds in opposite end sections, each pair of beds in each reactor being operable by sequential and coordinated treatment with a plurality of heat transfer fluids in a plurality of processing stages, and first and second valves located adjacent the reactor end sections with rotatable members having multiple ports and associated portions for separating the hydride beds at each of the end sections into groups and for simultaneously directing a plurality of heat transfer fluids to the different groups. As heat is being generated by a group of beds, others are being regenerated so that heat is continuously available for space heating. As each of the processing stages is completed for a hydride bed or group of beds, each valve member is rotated causing the heat transfer fluid for the heat processing stage to be directed to that bed or group of beds. Each of the end sections are arranged to form a closed perimeter and the valve member may be rotated repeatedly about the perimeter to provide a continuous operation. Both valves are driven by a common motor to provide a coordinated treatment of beds in the same reactors. The heat pump apparatus is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators but may be used with any source of heat, including a source of low-grade heat.
Nelson, Paul A. (Wheaton, IL); Horowitz, Jeffrey S. (Woodridge, IL)
Active microchannel heat exchanger
The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The active microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.
Tonkovich, Anna Lee Y. (Pasco, WA); Roberts, Gary L. (West Richland, WA); Call, Charles J. (Pasco, WA); Wegeng, Robert S. (Richland, WA); Wang, Yong (Richland, WA)
Switchable heat pipe assembly
The heat pipe assembly is formed into an H-shape or a Y-shape. The H-shaped configuration comprises two heat pipes, each having condenser and evaporator sections with wicking therein coupled by a tube with wick at their evaporator sections. The Y-shaped configuration utilizes a common evaporator section in place of the two evaporator sections of the H-shaped configuration. In both configurations, the connection between the vapor spaces of the two heat pipes equalizes vapor pressure within the heat pipes. Although both heat pipes have wicks, they have sufficient fluid only to saturate a single pipe. If heat is applied to the condenser section of one of the pipes, this heat pipe becomes inoperative since all the fluid is transferred to the second pipe which can operate with a lower thermal load.
Sun, T.H.; Basiulis, A.
Residential Heating Oil Prices
This chart highlights residential heating oil prices for the current and This chart highlights residential heating oil prices for the current and past heating season. As you can see, prices have started the heating season, about 40 to 50 cents per gallon higher than last year at this time. The data presented are from EIA's State Heating Oil and Propane Program. We normally collect and publish this data twice a month, but given the low stocks and high prices, we started tracking the prices weekly. These data will also be used to determine the price trigger mechanism for the Northeast Heating Oil Reserve. The data are published at a State and regional level on our web site. The slide is to give you some perspective of what is happening in these markets, since you probably will get a number of calls from local residents about their heating fuels bills
standing of the heat transfer processes associated withto investigate the heat transfer and related processes in an
Carbon Material Based Heat Exchanger for Waste Heat Recovery ...
Industrial processing plants Nuclear power Solar power ... Carbon Material Based Heat Exchanger for Waste Heat Recovery from Engine Exhaust Contact:
A model for improvement of water heating heat exchanger designs for residential heat pump water heaters.
??Heat pump water heaters are a promising technology to reduce energy use and greenhouse gas emissions. A key component is the water heating heat exchanger.� (more)
Weerawoot, Arunwattana
Thermodynamics of electrolyte mixtures. Activity and osmotic coefficients consistent with the higher-order limiting law for symmetrical mixing
The parameters for symmetrical mixing of ions of the same sign in the virial-coefficient (Pitzer) system are evaluated from literature data for 25/sup 0/C in a manner consistent with the higher-order limiting law of Friedman. Twenty-four systems involve cation mixing with a common anion and fourteen involve anion mixing with a common cation. Heat of mixing data were similarly treated in a recent publication; the results give the temperature coefficients of some of these same parameters. The combined results yield the mixing parameters as functions of temperature on a basis both self-consistent and in accord with the limiting law. The results also yield, for a few systems without a common ion, predicted values in good agreement with experimental data.
Yang, J.; Pitzer, K.S.
PreHeat: controlling home heating using occupancy prediction
Home heating is a major factor in worldwide energy use. Our system, PreHeat, aims to more efficiently heat homes by using occupancy sensing and occupancy prediction to automatically control home heating. We deployed PreHeat in five homes, three in the ... Keywords: energy, environment, home heating, prediction, sensing
James Scott; A.J. Bernheim Brush; John Krumm; Brian Meyers; Michael Hazas; Stephen Hodges; Nicolas Villar
of air-source heat pumps. Absorption Heat Pump Uses heat as its energy source. Geothermal Heat Pumps Use the constant temperature of the earth as the exchange medium instead...
Multivariate linear recursions with Markov-dependent coefficients
We study a linear recursion with random Markov-dependent coefficients. In a ''regular variation in, regular variation out'' setup we show that its stationary solution has a multivariate regularly varying distribution. This extends results previously ... Keywords: Heavy tails, Multivariate random recursions, Multivariate regular variation, Random vector equations, Stochastic difference equation, Tail asymptotic, primary, secondary
Diana Hay; Reza Rastegar; Alexander Roitershtein
Lower bounds on the bounded coefficient complexity of bilinear maps
We prove lower bounds of order n log n for both the problem of multiplying polynomials of degree n, and of dividing polynomials with remainder, in the model of bounded coefficient arithmetic circuits over the complex numbers. These ... Keywords: Algebraic complexity, bilinear circuits, lower bounds, singular values
Peter B�rgisser; Martin Lotz
Young modulus dependence of nanoscopic friction coefficient in hard coatings
with miniature moving parts, such as micro- electromechanical systems and hard-disk drives.1,2 A betterYoung modulus dependence of nanoscopic friction coefficient in hard coatings Elisa Riedoa with varying hardness obtained by different growth temperatures. For the CrN films, we show that the changes
Brune, Harald
Evaluating transport coefficients in real time thermal field theory
Transport coefficients in a hadronic gas have been calculated earlier in the imaginary time formulation of thermal field theory. The steps involved are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we carry out both the steps in the real time formulation.
S. Mallik; Sourav Sarkar
Electromagnetic fields and transport coefficients in a hot pion gas
We present recent results on finite temperature electromagnetic form factors and the electrical conductivity in a pion gas. The standard Chiral Perturbation Theory power counting needs to be modified for transport coefficients. We pay special attention to unitarity and to possible applications for dilepton and photon production.
A. Gomez Nicola; D. Fernandez-Fraile
Evaluation of diffusion coefficients from nonlinear impurity profiles
At high concentrations, impurity diffusion in semiconductors is governed by nonlinear diffusion processes. Using similarity analysis, a general expression for evaluation of the diffusion coefficient from experimental impurity profiles derived for the case of redistributive diffusion of implanted impurities. This expression corresponds to the Boltzmann-Matano analysis for the case of diffusion with constant surface concentration.
Anderson, D.; Jeppson, K.O.
An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.
Swenson, Paul F. (Shaker Heights, OH); Moore, Paul B. (Fedhaven, FL)
Swenson, Paul F. (Cleveland, OH); Moore, Paul B. (Fedhaven, FL)
Development of a pressure gain combustor for improved cycle efficiency
This paper presents results from an experimental research program attempting to improve the thermodynamic efficiencies of gas-turbine combustors. An elementary thermodynamic analysis shows that the thermodynamic cycle efficiencies of gas turbines can be significantly improved by using unsteady combustion that achieves quasi-constant-volume combustion. The ability to produce the so-called pressure gain via this process has already been demonstrated by others for pressures less than 3 atmospheres. This paper presents experimental results for pressures up to 11 atmospheres, compares certain process parameters to a numerical simulation, and briefly examines the problem of scale-up. Results of pollutant measurements over the 2--11 atmospheric range of operation are also included.
Gemmen, R.S.; Richards, G.A.; Janus, M.C.
Casimir forces in multilayer magnetodielectrics with both gain and loss
A path-integral approach to the quantization of the electromagnetic field in a linearly amplifying magnetodielectric medium is presented. Two continua of inverted harmonic oscillators are used to describe the polarizability and magnetizability of the amplifying medium. The causal susceptibilities of the amplifying medium, with negative imaginary parts in finite frequency intervals, are identified and their relationships to microscopic coupling functions are determined. By carefully relating the two-point functions of the field theory to the optical Green functions, we calculate the Casimir energy and Casimir forces for a multilayer magnetodielectric medium with both gain and loss. We point out the essential differences with a purely passive layered medium. For a single layer, we find different bounds on the Casimir force for fully amplifying and for lossy media. The force is attractive in both cases, even if the medium exhibits negative refraction. From our Lagrangian we also derive by canonical quantization the postulates of the phenomenological theory of amplifying magnetodielectrics.
Amooghorban, Ehsan [Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens. Lyngby (Denmark); Department of Physics, University of Isfahan, Hezar Jarib Avenue, Isfahan (Iran, Islamic Republic of); Wubs, Martijn; Mortensen, N. Asger [Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens. Lyngby (Denmark); Kheirandish, Fardin [Department of Physics, University of Isfahan, Hezar Jarib Avenue, Isfahan (Iran, Islamic Republic of)
Measured winter performance of storm windows
or Prime/Storm Replacement Window Thermal Watts Solar WattsFactor and Solar Heat Gain Coefficient Prime or Prime/Stormdesigned interior storm window. ) Solar Heat Gain One does
U-092: Sudo Format String Bug Lets Local Users Gain Elevated...
2: Sudo Format String Bug Lets Local Users Gain Elevated Privileges U-092: Sudo Format String Bug Lets Local Users Gain Elevated Privileges January 31, 2012 - 5:45am Addthis...
Research on Convective Heat Transfer and Mass Transfer of the Evaporator in Micro/Mini-Channel
With the development of science and technology, various heating and cooling equipment have a development trend of micromation. Micro-fabrication processes make it possible to conduct research on condensation heat transfer in micro-channels. Based on the reviewers on the present household air conditioners, the potential requirements for new heat transfer enhancement used for household air conditioners are discussed. Investigations on condensation and boiling of refrigerants in mini/micro channels have indicated that the evaporator and condenser of air conditioner would be more efficient and more compact by using microchannels, and hence it could improve the coefficient of performance of air conditioners to meet the new energy conversion standards in China. The relationship between condensation heat transfer of refrigerants and surface physical characteristics of the evaporator are pointed out and analyzed in order to achieving the corresponding heat transfer coefficients.
Su, J.; Li, J.
Experimental study on condensation heat transfer of steam on vertical titanium plates with different surface energies
Visual experiments were employed to investigate heat transfer characteristics of steam on vertical titanium plates with/without surface modifications for different surface energies. Stable dropwise condensation and filmwise condensation were achieved on two surface modification titanium plates, respectively. Dropwise and rivulet filmwise co-existing condensation form of steam was observed on unmodified titanium surfaces. With increase in the surface subcooling, the ratio of area ({eta}) covered by drops decreased and departure diameter of droplets increased, resulting in a decrease in condensation heat transfer coefficient. Condensation heat transfer coefficient decreased sharply with the values of {eta} decreasing when the fraction of the surface area covered by drops was greater than that covered by rivulets. Otherwise, the value of {eta} had little effect on the heat transfer performance. Based on the experimental phenomena observed, the heat flux through the surface was proposed to express as the sum of the heat flux through the dropwise region and rivulet filmwise region. The heat flux through the whole surface was the weighted mean value of the two regions mentioned above. The model presented explains the gradual change of heat transfer coefficient for transition condensation with the ratio of area covered by drops. The simulation results agreed well with the present experimental data when the subcooling temperature is lower than 10 C. (author)
Baojin, Qi; Li, Zhang; Hong, Xu; Yan, Sun [State-Key Laboratory of Chemical Engineering, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237 (China)
Water-heating dehumidifier
A water-heating dehumidifier includes a refrigerant loop including a compressor, at least one condenser, an expansion device and an evaporator including an evaporator fan. The condenser includes a water inlet and a water outlet for flowing water therethrough or proximate thereto, or is affixed to the tank or immersed into the tank to effect water heating without flowing water. The immersed condenser design includes a self-insulated capillary tube expansion device for simplicity and high efficiency. In a water heating mode air is drawn by the evaporator fan across the evaporator to produce cooled and dehumidified air and heat taken from the air is absorbed by the refrigerant at the evaporator and is pumped to the condenser, where water is heated. When the tank of water heater is full of hot water or a humidistat set point is reached, the water-heating dehumidifier can switch to run as a dehumidifier.
Tomlinson, John J. (Knoxville, TN)
Waste heat rejection from geothermal power stations
Waste heat rejection systems for geothermal power stations have a significantly greater influence on plant operating performances and costs than do corresponding systems in fossil- and nuclear-fueled stations. With thermal efficiencies of only about 10%, geothermal power cycles can reject four times as much heat per kilowatt of output. Geothermal sites in the United States tend to be in water-short areas that could require use of more expensive wet/dry or dry-type cooling towers. With relatively low-temperature heat sources, the cycle economics are more sensitive to diurnal and seasonal variations in sink temperatures. Factors such as the necessity for hydrogen sulfide scrubbers in off-gas systems or the need to treat cooling tower blowdown before reinjection can add to the cost and complexity of goethermal waste heat rejection systems. Working fluids most commonly considered for geothermal cycles are water, ammonia, Freon-22, isobutane, and isopentane. Both low-level and barometric-leg direct-contact condensers are used, and reinforced concrete has been proposed for condenser vessels. Multipass surface condensers also have wide application. Corrosion problems at some locations have led to increased interest in titanium tubing. Studies at ORNL indicate that fluted vertical tubes can enhance condensing film coefficients by factors of 4 to 7.
Robertson, R C
Hydride heat pump
Method and apparatus for the use of hydrides to exhaust heat from one temperature source and deliver the thermal energy extracted for use at a higher temperature, thereby acting as a heat pump. For this purpose there are employed a pair of hydridable metal compounds having different characteristics working together in a closed pressure system employing a high temperature source to upgrade the heat supplied from a low temperature source.
Cottingham, James G. (Center Moriches, NY)
Heat storage duration
Both the amount and duration of heat storage in massive elements of a passive building are investigated. Data taken for one full winter in the Balcomb solar home are analyzed with the aid of sub-system simulation models. Heat storage duration is tallied into one-day intervals. Heat storage location is discussed and related to overall energy flows. The results are interpreted and conclusions drawn.
Waste Heat Management Options: Industrial Process Heating Systems
Heat Management Options Heat Management Options Industrial Process Heating Systems By Dr. Arvind C. Thekdi E-mail: email@example.com E3M, Inc. August 20, 2009 2 Source of Waste Heat in Industries * Steam Generation * Fluid Heating * Calcining * Drying * Heat Treating * Metal Heating * Metal and Non-metal Melting * Smelting, agglomeration etc. * Curing and Forming * Other Heating Waste heat is everywhere! Arvind Thekdi, E3M Inc Arvind Thekdi, E3M Inc 3 Waste Heat Sources from Process Heating Equipment * Hot gases - combustion products - Temperature from 300 deg. F. to 3000 deg.F. * Radiation-Convection heat loss - From temperature source of 500 deg. F. to 2500 deg. F. * Sensible-latent heat in heated product - From temperature 400 deg. F. to 2200 deg. F. * Cooling water or other liquids - Temperature from 100 deg. F. to 180 deg. F.
2005 Residential Energy Consumption Survey Form EIA-457A (2005)--Household Questionnaire OMB No.: 1905-0092, Expiring May 31, 2008 33 Section D: SPACE HEATING
Controlling the Heat Transfer
Through experimental validation that air conduction is shown to be typically the dominant thermal transport mechanism in the contact region, the heat conduction
Heating Fuel Comparision Calculator
Wood, Pellet, Corn (kernel), and Coal Heaters Heating Fuel Comparison Calculator Instructions and Guidance Residential Fuel/Energy Price Links Spot Prices, Daily
Heat and mass exchanger
A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.
Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)
Convection Heat Transfer
...Heat-Transfer Equations, Fundamentals of Modeling for Metals Processing, Vol 22A, ASM Handbook, ASM International, 2009, p 625�??658...
HEATS: Thermal Energy Storage
HEATS Project: The 15 projects that make up ARPA-E�s HEATS program, short for �High Energy Advanced Thermal Storage,� seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.
Oceanic Heat Flux Calculation
The authors review the procedure for the direct calculation of oceanic heat flux from hydrographic measurements and set out the full �recipe� that is required.
Sheldon Bacon; Nick Fofonoff
Passive solar space heating
An overview of passive solar space heating is presented indicating trends in design, new developments, performance measures, analytical design aids, and monitored building results.
about: Conventional Storage Water Heaters Demand (Tankless or Instantaneous) Water Heaters Heat Pump Water Heaters Solar Water Heaters Tankless Coil and Indirect Water Heaters...
Heat pipe technology issues
Critical high temperature, high power applications in space nuclear power designs are near the current state of the art of heat pipe technology in terms of power density, operating temperature, and lifetime. Recent heat pipe development work at Los Alamos National Laboratory has involved performance testing of typical space reactor heat pipe designs to power levels in excess of 19 kW/cm/sup 2/ axially and 300 W/cm/sup 2/ radially at temperatures in the 1400 to 1500 K range. Operation at conditions in the 10 kW/cm/sup 2/ range has been sustained for periods of up to 1000 hours without evidence of performance degradation. The effective length for heat transport in these heat pipes was from 1.0 to 1.5 M. Materials used were molybdenum alloys with lithium employed as the heat pipe operating fluid. Shorter, somewhat lower power, molybdenum heat pipes have been life tested at Los Alamos for periods of greater than 25,000 hours at 1700 K with lithium and 20,000 hours at 1500/sup 0/K with sodium. These life test demonstrations and the attendant performance limit investigations provide an experimental basis for heat pipe application in space reactor design and represent the current state-of-the-art of high temperature heat pipe technology.
Heat pump arrangement
The invention concerns a heat pump arrangement for heating of houses. The arrangement comprises a compressor, a condensor and a vaporizer, which is a part of an icing machine. The vaporizer is designed as a heat exchanger and is connected to a circulation system comprising an accumulator, to which the ice slush from the icing machine is delivered. Water from the accumulator is delivered to the icing machine. The water in the accumulator can be heated E.G. By means of a solar energy collector, the outdoor air etc. Surface water or waste water from the household can be delivered to the accumulator and replace the ice slush therein.
Abrahamsson, T.; Hansson, K.
Heat rejection system
A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.
Smith, Gregory C. (Richland, WA); Tokarz, Richard D. (Richland, WA); Parry, Jr., Harvey L. (Richland, WA); Braun, Daniel J. (Richland, WA)
Promotion of efficient heat pumps for heating (ProHeatPump)
and towns have (some) district heating, and DH currently supplies 1% of heating for buildings in Norway.2 to district heating if there is a supply. According to HP industry representatives, howeverProject Promotion of efficient heat pumps for heating (ProHeatPump) EIE/06/072 / S12
Monthly average clear-sky broadband irradiance database for worldwide solar heat gain and building cooling load calculations
This paper establishes the formulation of a new clear-sky solar radiation model appropriate for algorithms calculating cooling loads in buildings. The aim is to replace the ASHRAE clear-sky model of 1967, whose limitations are well known and are reviewed. The new model is derived in two steps. The first step consists of obtaining a reference irradiance dataset from the REST2 model, which uses a high-performance, validated, two-band clear-sky algorithm. REST2 requires detailed inputs about atmospheric conditions such as aerosols, water vapor, ozone, and ground albedo. The development of global atmospheric datasets used as inputs to REST2 is reviewed. For the most part, these datasets are derived from space observations to guarantee universality and accuracy. In the case of aerosols, point-source terrestrial measurements were also used as ground truthing of the satellite data. The second step of the model consists of fits derived from a REST2-based reference irradiance dataset. These fits enable the derivation of compact, but relatively accurate expressions, for beam and diffuse clear-sky irradiance. The fitted expressions require the tabulation of only two pseudo-optical depths for each month of the year. The resulting model, and its tabulated data, are expected to be incorporated in the 2009 edition of the ASHRAE Handbook of Fundamentals. (author)
Gueymard, Christian A. [Solar Consulting Services, P.O. Box 392, Colebrook, NH 03576 (United States); Thevenard, Didier [Numerical Logics Inc., 498 Edenvalley Cres., Waterloo, Ont. (Canada)
Layer Calculation. � ASHRAE Trans. 100(pt. 1): 1065-1072.Layer Calculation. � ASHRAE Trans. 100(pt.1): 1073-1086.
Antarctic Bottom Water Warming and Freshening: Contributions to Sea Level Rise, Ocean Freshwater Budgets, and Global Heat Gain
Freshening and warming of Antarctic Bottom Water (AABW) between the 1980s and 2000s are quantified, assessing the relative contributions of water-mass changes and isotherm heave. The analysis uses highly accurate, full-depth, ship-based, ...
Sarah G. Purkey; Gregory C. Johnson
thermal and daylighting impacts of shading systems. Theseglazing the system. Modern energy and daylighting analysissystem. In this paper a shade screen used in the LBNL daylighting
Jonsson, Jacob C.
Implicit continuum mechanics approach to heat conduction in granular materials
In this paper, we derive a properly frame-invariant implicit constitutive relationship for the heat flux vector for a granular medium (or a density-gradient-type fluid). The heat flux vector is commonly modeled by Fourier�s law of heat conduction, and for complex materials such as nonlinear fluids, porous media, or granular materials, the coefficient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematic parameters such as temperature, shear rate, porosity, concentration, etc. In this paper, we extend the approach of Massoudi [Massoudi, M. Math. Methods Appl. Sci. 2006, 29, 1585; Massoudi, M. Math. Methods Appl. Sci. 2006, 29, 1599], who provided explicit constitutive relations for the heat flux vector for flowing granular materials; in order to do so, we use the implicit scheme suggested by Fox [Fox, N. Int. J. Eng. Sci. 1969, 7, 437], who obtained implicit relations in thermoelasticity.
Massoudi, M.; Mehrabadi, M.
Heat Pipe Integrated Microsystems
The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached to the satellite such as solar panels, radiators, antenna and.telescopes (for communications or sensors). Finally, the packages make thermal contact to the surface of the silicon heat pipe through soft thermal pads. Electronic components can be placed on both sides of the flexible circuit interconnect. Silicon heat pipes have a number of advantages over heat pipe constructed from other materials. Silicon heat pipes offer the ability to put the heat pipe structure beneath the active components of a processed silicon wafer. This would be one way of efficiently cooling the heat generated by wafer scale integrated systems. Using this technique, all the functions of a satellite could be reduced to a few silicon wafers. The integration of the heat pipe and the electronics would further reduce the size and weight of the satellite.
Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.
The Cost of Heat Exchanger Fouling in the U. S. Industries
Fouling of heat exchangers costs the U.S. industries hundreds of millions of dollars every year in increased equipment costs, maintenance costs, energy losses and losses in production. The designer of heat exchangers usually allows for fouling by using a fouling factor in the design which results in additional capital cost of the heat exchanger. As fouling deposits build up in a heat exchanger, its performance will start to deteriorate and less energy will be transferred through the unit. A plot is provided that gives the percent decrease in heat flux, for a constant driving temperature difference, as a function of the clean overall heat transfer coefficient and the fouling factor. Another plot gives the increase in surface area due to fouling for the same heat transfer rate and driving temperature difference, as a function of the clean overall heat transfer coefficient and the fouling factor. The overall heat transfer market was divided into four sectors: the chemical, petroleum, electric utility and other industries. The 1982 U.S. sales of all industrial heat exchangers, excepting boilers and automotive radiators, was about 285,000 units amounting to about $1.6 billion. The total heat duty of all the heat exchangers in industrial operation, including electric utilities, was estimated at 11.7 Quads. If this represented the amount of heat transferred through clean heat exchangers, the decrease in energy transferred due to fouling or the cost of fouling in terms of energy lost was estimated at 2.9 Quads annually. The cost of fouling, in providing for additional surface area to compensate for a decrease in heat transfer, was conservatively estimated at $180 million in 1982.
Rebello, W. J.; Richlen, S. L.; Childs, F.
Performance improvement of a solar heating system utilizing off-peak electric auxiliary
The design and construction of a heat pump system suitable for incorporating in a space solar heating system utilizing off-peak storage from the electric utility are described. The performance of the system is evaluated. The refrigerating capacity, heating capacity and compressor horsepower for a heat pump system using a piston type compressor are first determined. The heat pump design is also matched with the existing University of Toledo solar house heating system. The refrigerant is Freon-12 working between a condensing temperature of up to 172/sup 0/F and evaporator temperature between 0/sup 0/F and 75/sup 0/F. The heat pump is then installed. Performance indices for the heat pump and the heating system in general are defined and generated by the on-line computer monitoring system for the 1979/80 heating season operation. Monthly and seasonal indices such as heat pump coefficient of performance, collector efficiency, percent of heating load supplied by solar energy and individual components efficiencies in general are recorded. The data collected is then analyzed and compared with previously collected data. The improvement in the performance resulting from the addition of a piston type compressor with an external motor belt drive is then evaluated. Data collected points to the potentially improved operating performance of a solar heating system utilizing off-peak storage from the electric utility. Data shows that the seasonal percent of space heating load supplied by solar is 60% and the seasonal percent cost of space heating load supplied by solar is 82% with a solar collection coefficient of performance of 4.6. Data also indicates that such a system would pay for itself in 14 years when used in Northwest Ohio.
Eltimsahy, A.H.
Heat Pumps | Department of Energy
Heat Pumps Heat Pumps Heat Pumps Geothermal heat pumps are expensive to install but pay for themselves over time in reduced heating and cooling costs. Learn more about how geothermal heat pumps heat and cool buildings by concentrating the naturally existing heat contained within the earth -- a clean, reliable, and renewable source of energy. In moderate climates, heat pumps can be an energy-efficient alternative to furnaces and air conditioners. Several types of heat pumps are available, including air-source; geothermal; ductless, mini-split; and absorption heat pumps. Learn more about the different options and how to use your heat pump efficiently to save money and energy at home. Featured Heat Pump Systems A heat pump can provide an alternative to using your air conditioner. | Photo courtesy of iStockPhoto/LordRunar.
Microchannel Heat Exchangers with Carbon Dioxide
The objective of the present study was to determine the performance of CO{sub 2} microchannel evaporators and gas coolers in operational conditions representing those of residential heat pumps. A set of breadboard prototype microchannel evaporators and gas coolers was developed and tested. The refrigerant in the heat exchangers followed a counter cross-flow path with respect to the airflow direction. The test conditions corresponded to the typical operating conditions of residential heat pumps. In addition, a second set of commercial microchannel evaporators and gas coolers was tested for a less comprehensive range of operating conditions. The test results were reduced and a comprehensive data analysis, including comparison with the previous studies in this field, was performed. Capacity and pressure drop of the evaporator and gas cooler for the range of parameters studied were analyzed and are documented in this report. A gas cooler performance prediction model based on non-dimensional parameters was also developed and results are discussed as well. In addition, in the present study, experiments were conducted to evaluate capacities and pressure drops for sub-critical CO{sub 2} flow boiling and transcritical CO{sub 2} gas cooling in microchannel heat exchangers. An extensive review of the literature failed to indicate any previous systematic study in this area, suggesting a lack of fundamental understanding of the phenomena and a lack of comprehensive data that would quantify the performance potential of CO{sub 2} microchannel heat exchangers for the application at hand. All experimental tests were successfully conducted with an energy balance within {+-}3%. The only exceptions to this were experiments at very low saturation temperatures (-23 C), where energy balances were as high as 10%. In the case of evaporators, it was found that a lower saturation temperature (especially when moisture condensation occurs) improves the overall heat transfer coefficient significantly. However, under such conditions, air side pressure drop also increases when moisture condensation occurs. An increase in airflow rate also increases the overall heat transfer coefficient. Air side pressure drop mainly depends on airflow rate. For the gas cooler, a significant portion of the heat transfer occurred in the first heat exchanger module on the refrigerant inlet side. The temperature and pressure of CO{sub 2} significantly affect the heat transfer and fluid flow characteristics due to some important properties (such as specific heat, density, and viscosity). In the transcritical region, performance of CO{sub 2} strongly depends on the operating temperature and pressure. Semi-empirical models were developed for predictions of CO{sub 2} evaporator and gas cooler system capacities. The evaporator model introduced two new factors to account for the effects of air-side moisture condensate and refrigerant outlet superheat. The model agreed with the experimental results within {+-}13%. The gas cooler model, based on non-dimensional parameters, successfully predicted the experimental results within {+-}20%. Recommendations for future work on this project include redesigning headers and/or introducing flow mixers to avoid flow mal-distribution problems, devising new defrosting techniques, and improving numerical models. These recommendations are described in more detail at the end of this report.
Zhao, Y.; Ohadi, M.M.; Radermacher, R.
Verifying the Dependence of Fractal Coefficients on Different Spatial Distributions
A fractal distribution requires that the number of objects larger than a specific size r has a power-law dependence on the size N(r) = C/r{sup D}propor tor{sup -D} where D is the fractal dimension. Usually the correlation integral is calculated to estimate the correlation fractal dimension of epicentres. A 'box-counting' procedure could also be applied giving the 'capacity' fractal dimension. The fractal dimension can be an integer and then it is equivalent to a Euclidean dimension (it is zero of a point, one of a segment, of a square is two and of a cube is three). In general the fractal dimension is not an integer but a fractional dimension and there comes the origin of the term 'fractal'. The use of a power-law to statistically describe a set of events or phenomena reveals the lack of a characteristic length scale, that is fractal objects are scale invariant. Scaling invariance and chaotic behavior constitute the base of a lot of natural hazards phenomena. Many studies of earthquakes reveal that their occurrence exhibits scale-invariant properties, so the fractal dimension can characterize them. It has first been confirmed that both aftershock rate decay in time and earthquake size distribution follow a power law. Recently many other earthquake distributions have been found to be scale-invariant. The spatial distribution of both regional seismicity and aftershocks show some fractal features. Earthquake spatial distributions are considered fractal, but indirectly. There are two possible models, which result in fractal earthquake distributions. The first model considers that a fractal distribution of faults leads to a fractal distribution of earthquakes, because each earthquake is characteristic of the fault on which it occurs. The second assumes that each fault has a fractal distribution of earthquakes. Observations strongly favour the first hypothesis.The fractal coefficients analysis provides some important advantages in examining earthquake spatial distribution, which are: - Simple way to quantify scale-invariant distributions of complex objects or phenomena by a small number of parameters. - It is becoming evident that the applicability of fractal distributions to geological problems could have a more fundamental basis. Chaotic behaviour could underlay the geotectonic processes and the applicable statistics could often be fractal.The application of fractal distribution analysis has, however, some specific aspects. It is usually difficult to present an adequate interpretation of the obtained values of fractal coefficients for earthquake epicenter or hypocenter distributions. That is why in this paper we aimed at other goals - to verify how a fractal coefficient depends on different spatial distributions. We simulated earthquake spatial data by generating randomly points first in a 3D space - cube, then in a parallelepiped, diminishing one of its sides. We then continued this procedure in 2D and 1D space. For each simulated data set we calculated the points' fractal coefficient (correlation fractal dimension of epicentres) and then checked for correlation between the coefficients values and the type of spatial distribution.In that way one can obtain a set of standard fractal coefficients' values for varying spatial distributions. These then can be used when real earthquake data is analyzed by comparing the real data coefficients values to the standard fractal coefficients. Such an approach can help in interpreting the fractal analysis results through different types of spatial distributions.
Gospodinov, Dragomir [Plovdiv University 'Paisii Hilendarski', 24, Tsar Asen Str., Plovdiv (Bulgaria); Geophysical Institute of Bulgarian Academy of Sciences, Akad. G. Bonchev Str., bl.3, Sofia (Bulgaria); Marekova, Elisaveta; Marinov, Alexander [Plovdiv University 'Paisii Hilendarski', 24, Tsar Asen Str., Plovdiv (Bulgaria)
Thermal Performance of a Novel Heat Transfer Fluid Containing Multiwalled Carbon Nanotubes and Microencapsulated Phase Change Materials
The present research work aims to develop a new heat transfer fluid by combining multiwalled carbon nanotubes (MWCNT) and microencapsulated phase change materials (MPCMs). Stable nanofluids have been prepared using different sizes of multiwalled carbon nanotubes and their properties like thermal conductivity and viscosity have been measured. Microencapsulated phase change material slurries containing microcapsules of octadecane have been purchased from Thies Technology Inc. Tests have been conducted to determine the durability and viscosity of the MPCM slurries. Heat transfer experiments have been conducted to determine the heat transfer coefficients and pressure drop of the MWCNT nanofluids and MPCM slurries under turbulent flow and constant heat flux conditions. The MPCM slurry and the MWCNT nanofluid have been combined to form a new heat transfer fluid. Heat transfer tests have been conducted to determine the heat transfer coefficient and the pressure drop of the new fluid under turbulent flow and constant heat flux conditions. The potential use of this fluid in convective heat transfer applications has also been discussed. The heat transfer results of the MPCM slurry containing octadecane microcapsules was in good agreement with the published literature. The thermal conductivity enhancement obtained for MWCNTs with diameter (60-100 nm) and length (0.5-40?m) was 8.11%. The maximum percentage enhancement (compared to water) obtained in the heat transfer coefficient of the MWCNT nanofluid was in the range of 20-25%. The blend of MPCMs and MWCNTs was highly viscous and displayed a shear thinning behavior. Due to its high viscosity, the flow became laminar and the heat transfer performance was lowered. It was interesting to observe that the value of the maximum local heat transfer coefficient achieved in the case of the blend (laminar flow), was comparable to that obtained in the case of the MPCM slurry (turbulent flow). The pressure drop of the blend was lower than that of the MWCNT nanofluid.
Tumuluri, Kalpana
Design methodologies for energy conservation and passive heating of buildings utilizing improved building components. Progress report No. 3, January 15--April 15, 1978
The recently completed MIT Solar Building 5 demonstrates direct gain solar space heating through the use of new architectural finish materials. February 1978 measurements are summarized. Results indicate the building performed nearly as expected.
Habraken, N.J.; Johnson, T.E.
Released: September, 2008 Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ........................... 1,870 1,276 322 138 133 43.0 29.4 7.4 3.2 3.1 Building Floorspace (Square Feet) 1,001 to 5,000 ........................... 243 151 34 40 18 78.7 48.9 11.1 13.0 5.7 5,001 to 10,000 .......................... 202 139 31 29 Q 54.8 37.6 8.5 7.9 Q 10,001 to 25,000 ........................ 300 240 31 21 7 42.5 34.1 4.4 3.0 1.1 25,001 to 50,000 ........................ 250 182 40 11 Q 41.5 30.2 6.6 1.9 Q 50,001 to 100,000 ...................... 236 169 41 8 19 35.4 25.2 6.2 1.2 2.8 100,001 to 200,000 .................... 241 165 54 7 16 36.3 24.8 8.1 1.0 2.4 200,001 to 500,000 .................... 199 130 42 11 16 35.0 22.8 7.5 1.9 2.8 Over 500,000 ............................. 198
Released: September, 2008 Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings ............................. 2,037 1,378 338 159 163 42.0 28.4 7.0 3.3 3.4 Building Floorspace (Square Feet) 1,001 to 5,000 ........................... 249 156 35 41 18 78.6 49.1 11.0 12.9 5.6 5,001 to 10,000 .......................... 218 147 32 31 7 54.8 37.1 8.1 7.9 1.7 10,001 to 25,000 ........................ 343 265 34 25 18 43.8 33.9 4.4 3.2 2.3 25,001 to 50,000 ........................ 270 196 41 13 Q 40.9 29.7 6.3 2.0 2.9 50,001 to 100,000 ...................... 269 186 45 13 24 35.8 24.8 6.0 1.8 3.2 100,001 to 200,000 .................... 267 182 56 10 19 35.4 24.1 7.4 1.3 2.6 200,001 to 500,000 .................... 204 134 43 11 17 34.7 22.7 7.3 1.8 2.9 Over 500,000 .............................
Waste Heat Recovery from Industrial Process Heating Equipment -
Waste Heat Recovery from Industrial Process Heating Equipment - Waste Heat Recovery from Industrial Process Heating Equipment - Cross-cutting Research and Development Priorities Speaker(s): Sachin Nimbalkar Date: January 17, 2013 - 11:00am Location: 90-2063 Seminar Host/Point of Contact: Aimee McKane Waste heat is generated from several industrial systems used in manufacturing. The waste heat sources are distributed throughout a plant. The largest source for most industries is exhaust / flue gases or heated air from heating systems. This includes the high temperature gases from burners in process heating, lower temperature gases from heat treat, dryers, and heaters, heat from heat exchangers, cooling liquids and gases etc. The previous studies and direct contact with the industry as well as equipment suppliers have shown that a large amount of waste heat is not
Simplified solar fraction estimation for space and water heating at DOD installations. Final report
A set of nomographs is provided which can be used to estimate the average annual solar fraction for solar space and water heating at a large number of DOD facilities. The solar fraction estimated from the nomograph is in close agreement with F-Chart 3.0 and allows for variation of the following parameters: annual load, collector area, collector transmittance-absorption coefficient, and collector overall loss coefficient.
Pacheco, N.S.; Kniola, D.G.; Sheedy, J.F.; Scari, R.J.
Estimation of tracer diffusion coefficients of ions in aqueous solution
Equations are given for estimating tracer diffusion coefficients D/sub i//sup 0/ of ions at infinite dilution in terms of limiting ionic conductances ..lambda../sub i//sup 0/. Also given are generalized Nernst-Hartley equations for binary and multicomponent diffusion coefficients D/sup 0/ and D/sub ij//sup 0/, respectively, at infinite dilution. Data, estimates, and correlations for ..lambda../sub i//sup 0/ at 25/sup 0/C and other temperatures are discussed. Estimated values of ..lambda../sub i//sup 0/ are tabulated from 0-300/sup 0/C for ions of waste isolation interest and for ions of economic interest in geothermal brines. Estimates of their tracer diffusion coefficients at infinite dilution are tabulated. A rule of thumb, good to a factor of 2, is presented. Very limited data (available only at 25/sup 0/C) indicate that D/sub i//D/sub i//sup 0/ generally declines as the concentration of salt or supporting electrolyte increases. 6 figures, 2 tables.
Miller, D.G.
ARM: 2-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
DOE Data Explorer (OSTI)
2-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
Chitra Sivaraman; Connor Flynn
ARM: 10-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
10-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
Rob Newsom; John Goldsmith
ARM: 1-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
1-minute Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
ARM: 10-second Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
10-second Raman Lidar: aerosol scattering ratio and backscattering coefficient profiles, from first Ferrare algorithm
A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to faciliate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.
Greiner, Leonard (2853-A Hickory Pl., Costa Mesa, CA 92626)
A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate intallation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.
A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure, as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer.
Unstable heat pipes
Heat pipes are an important feature of models of vapor-dominated geothermal reservoirs. Numerical experiments reveal that a vapor-dominated heat pipe is unstable if pressure is controlled at shallow levels. This instability is discussed in physical terms, and some implications for geothermal reservoirs are considered. 9 refs., 10 figs.
McGuinness, M.J.; Pruess, K.
Home heating system
A home heating system is disclosed that has a furnace with a combustion chamber for burning fuel and creating heat, and a chimney with a draft therein. An improvement is described that has an exhaust flue connected between the combustion chamber and the chimney for venting heated exhaust products from the furnace, a heat reclaimer connected into the exhaust flue between the combustion chamber and the chimney for reclaiming heat from the heated exhaust product, and an outside air line for supplying air from the outside of the house to the combustion chamber. A first flue portion of the exhaust flue is connected between the combustion chamber and the heat reclaimer, and a second insulated flue portion of the exhaust flue is connected between the heat reclaimer and the chimney. An outside air by-pass or balancing line is connected between the outside air line and the chimney for satisfying the chimney suction at flame-out. A flow sensing and regulating device may be connected into the outside air line for regulating the flow or air so that outside air is supplied to the furnace only when fuel is burned therein.
Solar heat regulator
A solar heat regulating device is described for selectively heating with sunlight the air inside a building having a window and shielding and insulating the air inside the building from the heat of sunlight outside the building including: a frame for mounting the solar heat regulating device inside the building and adjacent to the window; a plurality of hollow vanes, each of the vanes having at least one passageway for passing air therethrough; the vanes having a heat absorptive surface on a first side thereof which allows solar radiation impinging on the heat absorptive surface to heat the air contained in the one passageway of the vanes; the vanes having a heat reflective surface on a second side of the vanes which reflects the solar radiation impinging on the second side of the vanes and shields the inside of the building from solar radiation impinging on the vanes; and the vanes having side portions extending between the first and second sides of the vanes, the side portions, and the first and second sides forming the one passageway through each of the vanes, the side portions and the first and second sides of the vanes terminating in top end and bottom end portions.
Boynton, S.L.
Microchannel heat sink assembly
The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watertight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures. 13 figs.
Bonde, W.L.; Contolini, R.J.
First university owned district heating system using biomass heat
Highlights · First university owned district heating system using biomass heat · Capacity: 15 MMBtu Main Campus District Heating Performance · Avoided: 3500 tonnes of CO2 · Particulate: less than 10 mg District Heating Goals To displace 85% of natural gas used for core campus heating. Fuel Bunker Sawmill
Northern British Columbia, University of