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1、英文翻譯英文翻譯ChilledWaterSystems[1]Chilledwatersystemswereusedinlessthan4%ofcommercialbuildingsintheU.S.in1995.Howeverbecausechillersareusuallyinstalledinlargerbuildingschillerscooledover28%oftheU.S.commercialbuildingflospace

2、thatsameyear(DOE1998).Fivetypesofchillersarecommonlyappliedtocommercialbuildings:reciprocatingscrewscrollcentrifugalabsption.Thefirstfourutilizethevapcompressioncycletoproducechilledwater.Theydifferprimarilyinthetypeofco

3、mpressused.Absptionchillersutilizethermalenergy(typicallysteamcombustionsource)inanabsptioncyclewitheitheranammoniawaterwaterlithiumbroesolutiontoproducechilledwater.OverallSystemFigure4.2.2showsasimplerepresentationofad

4、ualchillerapplicationwithallthemajauxiliaryequipment.Anestimated86%ofchillersareappliedinmultiplechillerarrangementslikethatshowninthefigure(BitondoTozzi1999).Inchilledwatersystemsreturnwaterfromthebuildingiscirculatedth

5、rougheachchillerevapatwhereitiscooledtoanacceptabletemperature(typically4to7C)(39to45F).Thechilledwateristhendistributedtowatertoairheatexchangersspreadthroughoutthefacility.Intheseheatexchangersairiscooleddehuifiedbythe

6、coldwater.Duringtheprocessthechilledwaterincreasesintemperaturemustbereturnedtothechiller(s).ThechillersshowninFigure4.2.2arewatercooledchillers.Wateriscirculatedthroughthecondenserofeachchillerwhereitabsbsheatenergyreje

7、ctedfromthehighpressurerefrigerant.Thewateristhenpumpedtoacoolingtowerwherethewateriscooledthroughanevapationprocess.Coolingtowersaredescribedinalatersection.Chillerscanalsobeaircooled.Inthisconfigurationthecondenserwoul

8、dbearefrigeranttoairheatexchangerwithairabsbingtheheatenergyrejectedbythehighpressurerefrigerant.Chillersnominallyrangeincapacitiesfrom30to18000kW(8to5100ton).MostchillerssoldintheU.S.areelectricutilizevapcompressionrefr

9、igerationtoproducechilledwater.Compresssfthesesystemsareeitherreciprocatingscrewscrollcentrifugalindesign.Asmallnumberofcentrifugalchillersaresoldthatuseeitheraninternalcombustionenginesteamdriveinsteadofanelectricmottod

10、rivethecompress.[1]節(jié)選自JamesB.Bradfdetal.“HVACEquipmentSystems”.HbookofHeatingVentilationAirConditioning.Ed.JanF.Kreider.BocaRatonCRCPressLLC.2001浙江海洋學(xué)院畢業(yè)設(shè)計(jì)3inthebuildingwillachilleroperatenearitsratedcapacity.Asaconseque

11、nceitisimptanttoknowhowtheefficiencyofthechillervarieswithpartloadcapacity.Figure4.2.3showsarepresentativedataftheefficiency(inkWton)asafunctionofpercentagefullloadcapacityfareciprocatingscrewscrollchillerplusacentrifuga

12、lchillerwithinletvanecontrolonewithvariablefrequencydrive(VFD)fthecompress.Thereciprocatingchillerincreasesinefficiencyasitoperatesatasmallerpercentageoffullload.Incontrasttheefficiencyofacentrifugalwithinletvanecontroli

13、srelativelyconstantuntiltheloadfallstoabout60%ofitsratedcapacityitskWtonincreasestoalmosttwiceitsfullyloadedvalue.FIGURE4.2.3Chillerefficiencyasafunctionofpercentageoffullloadcapacity.In1998theAirConditioningRefrigeratio

14、nInstitute(ARI)developedanewstardthatincpatesintotheirratingspartloadperfmanceofchillers(ARI1998c).Partloadefficiencyisexpressedbyasinglenumbercalledtheintegratedpartloadvalue(IPLV).TheIPLVtakesdatasimilartothatinFigure4

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