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1、CENRTRALCOOLINGANDHEATINGTheenergyusedtoheatandcoolmanybuildingsoftencomesfromacentrallocationinthefacility.Theenergyinputmaybecombinationofelectricity,oil,gas,coal,solar,geothermal,etc.Thisenergyistypicallyconvertedintohotorchilledwaterorsteamthatisdistributedthroughoutt
2、hefacilityforheatingandairconditioning(cooling).Centralizingthisfunctionkeepstheconversionequipmentinonelocationanddistributestheheatingandcoolinginamorereadilyusableform.Also,acentralcoolingandheatingplantprovideshigherdiversityandgenerallyoperatesmoreefficientlywithlowe
3、rcentrallocationandapotentiallylargedistributionsystem.Thislessonaddressesthedesignalternativesthatshouldbeconsideredwhencentralizingthecoolingandheatingsourcesinafacility.Theeconomicsofthesesystemsrequireextensiveanalysis.Boilers,gas,steam,andelectricturbine-drivencentri
4、fugalrefrigerationunits;andabsorptionchillersmaybeinstalledincombinationinoneplant.Inlargebuildingswithcoreareasthatrequirecoolingandperimeterareasrequireheating,oneofseveralheatreclaimsystemsmayheattheperimetertosaveenergy.Thechoiceofequipmentforacentralheatingandcooling
5、plantdependsonthefollowing:lRequiredcapacityandtypeofuselCostandtypesofenergyavailablelLocationandspacefortheequipmentroomlAstackforanyexhaustgasesanditsenvironmentimpactlSafetyrequirementsforthemechanicalroomandsurroundingareaslTypeofairdistributionsystemlOwningandopera
6、tingcostsManyelectricutilitiesimposeveryhighchargesforpeakpoweruseor,alternatively,offerincentivesforoff-peakuse.Thispolicyhasrenewedinterestinbothwaterandicethermalstorage.Thestoragecapacityinstalledforsummerloadlevelingmayalsobeavailableforuseinthewinter,makingheatrecla
7、imamoreviableoption.Withicestorage,thelow-temperatureicewatercanprovidecolderairthanthatavailablefromaconventionalsystemthatsuppliesairat10to13℃.Theuseofahigherwatertemperatureriseandalowersupplyairtemperature,lowerstherequiredpumpingandfanenergyand,insomeinstances,offset
8、stheenergypenaltyduetothelowertemperaturerequiredtomakeice.RefrigerationEquipmentThemajortypesof
