us . ▁Furthermore , ▁ab ▁an bars ▁tend ▁to ▁further ▁lower ▁the ▁temperature ▁of ▁the ▁water ▁due ▁to ▁the ▁fasc in ating ▁heat ▁resistance ▁properties ▁of ▁the ▁construction ▁material ▁used . ▁Near ▁free zing ▁temper atures ▁of ▁the ▁water ▁can ▁readily ▁be ▁observed ▁in ▁the ▁desert ▁central ▁city ▁of ▁N ae en ▁during ▁summer , ▁inside ▁an ▁ab ▁an bar ▁that ▁emp lo ys ▁multiple ▁wind catch ers . ▁Thus ▁the ▁Q an at / ab ▁an bar ▁system ▁was ▁easily ▁able ▁to ▁supply ▁the ▁needs ▁of ▁many ▁growing ▁cities ▁( such ▁as ▁medieval ▁Q az vin ) ▁year ▁round . ▁ ▁Location ▁ ▁Public ▁ab ▁an bars ▁were ▁often ▁built ▁wherever ▁demand ▁dict ated . ▁But ▁factors ▁such ▁as ▁access ibility ▁of ▁ab ▁an bars ▁to ▁kar izes , ▁ease ▁of ▁access ibility ▁of ▁the ▁public ▁to ▁the ▁ab ▁an bars , ▁and ▁a ▁hom ogeneous ▁density ▁of ▁the ▁ab ▁an bars ▁in ▁each ▁area ▁determined ▁the ▁size ▁and ▁location ▁of ▁an ▁ab ▁an bar . ▁ ▁As ▁an ▁example , ▁in ▁terms ▁of ▁network ▁coverage , ▁one ▁could ▁class ify ▁the ▁kar izes ▁of ▁Q az vin ▁into ▁three ▁groups : ▁ ▁North west ▁kar izes . ▁The ▁major ▁ones ▁were : ▁Kar iz ▁of ▁K hom ar ▁e ▁T ashi ▁( a ▁famous ▁viz ier ). ▁Kar iz ▁of ▁Ak h und ▁Kar iz ▁of ▁Shah ▁North ▁Kar izes . ▁The ▁major ▁ones ▁being : ▁Kar iz ▁of ▁Hal al ▁Ab ad ▁Kar iz ▁of ▁As g har ▁Kh ani