ASHRAE.HandBook_13-2008 CONDENSER WATER SYSTEMS

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1、RelatedCommercialResourcesCHAPTER13CONDENSERWATERSYSTEMSOnce-ThroughCityWaterSystems..............................................................................................13.1OpenCoolingTowerSystems...........................................................................

2、...........................13.1Low-Temperature(WaterEconomizer)Systems..........................................................................13.3Closed-CircuitEvaporativeCoolers............................................................................................13.3Over

3、pressurecausedbyThermalFluidExpansion.....................................................................13.3CONDENSERwatersystemsforrefrigerationprocessesarevelocitiesof1.5to3m/sfordesignflowrates.Apumpisnotclassifiedas(1)once-throughsystems,suchascitywatersys-requiredwherecity

4、waterisused.Wellwatercanbeusedinlieuoftems;or(2)recirculatingorcoolingtowersystems.citywater,connectedontheservicesideofthepumping/pressurecontrolsystem.Becausemostwellwaterhashighcalciumcontent,ONCE-THROUGHCITYWATERSYSTEMSscalingonthecondensersurfacescanbeaproblem.Figure1showsaw

5、ater-cooledcondenserusingcitywater.ThereturnisrunhigherthanthecondensersothatthecondenserisOPENCOOLINGTOWERSYSTEMSalwaysfullofwater.WaterflowthroughthecondenserismodulatedOpensystemshaveatleasttwopointsofinterfacebetweenthebyacontrolvalveinthesupplyordischargeline,usuallyactuated

6、systemwaterandtheatmosphere;theyrequireadifferentapproachfromcondenserheadpressureto(1)maintainaconstantcondensingtohydraulicdesign,pumpselection,andsizingthandoclosedhot-temperaturewithloadvariationsand(2)closewhentherefrigera-waterandchilled-watersystems.Someheatconservationsys

7、temstioncompressorturnsoff.Citywatersystemsshouldalwaysincluderelyonasplitcondenserheatingsystemthatincludesatwo-sectionapprovedbackflowpreventiondevicesandopen(airgap)drains.condenser.Onesectionofthecondensersuppliesheatforclosed-Whenmorethanonecondenserisusedonthesamecircuit,in

8、divid-circuitheatingorreheatsystems;theo