ASHRAE.4441-2001 Intelligent Control to Reduce Superheat Hunting

《ASHRAE.4441-2001 Intelligent Control to Reduce Superheat Hunting 》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、4441IntelligentControltoReduceSuperheatHuntingandOptimizeEvaporatorPerformanceinContainerRefrigerationP.G.Jolly,Ph.D.C.P.Tso,Ph.D.P.K.ChiaY.W.WongMemberASHRAEMemberASHRAEFuzzylogicisappliedtothecontrolofsuperheatintheevaporatorofacommercialcontainerrefrige

2、rationsystemusinganelectronicexpansionvalveandadaptivesuperheatcontrolalgo-rithmhasbeendevisedtoenhanceevaporatorperformance.Superheathuntinghasbeenreduced,andanimprovementof7.5%inthecoefficientofperformanceoftherefrigerationsys-temcanberealizedusingadapti

3、vesuperheatcontrolascomparedtoconstantsuperheatcontrolstrategy.Intelligentcontrolgivesamorestablesuperheatcontrolintheinitialevaporatorpull-downandeffectsafasterpulldownrateofthetemperatureofthecontainerbox.INTRODUCTIONContainerrefrigerationplaysanimportan

4、troleintheworldwidedistributionofperishablefoodproducts.Enhancingtheperformanceofcontainerrefrigerationisanessentialareathathasrecentlygainedimportance.Someoftheimportantcriteriaforcontainerrefrigerationperfor-manceareastablesuperheatcontrolandarapidpull-d

5、owntothedesiredcontainertemperature.Theperformanceofexpansionvalvesplaysacrucialroleinrefrigerationsinceoptimalsuper-heatcontrolfortheexpansionvalveresultsinthecorrectmassofrefrigerantintotheevaporatorthusleadingtobetterevaporatorperformance.Formanyyears,t

6、hermostaticexpansionvalves(TEV)havebeenusedforcontrollingevaporatorliquidsupply,andthissystemhasbecomewidelyusedinpractice.However,duetotheinherentstabilityproblemofsuperheatcontrolintheTEV-evaporatorsystem,anumberofrefrigerationcomponentmanufacturershavei

7、ntro-ducedtheelectronicexpansionvalve(EEV)whichhassuperiorperformancecomparedtotheconventionalmechanicalTEV(Gruhle1985,TassouandAl-Nizari1991,TassouandAl-Nazari1993a,b,HernandezandLopez1994).WiththeimplementationoftheEEV,avarietyofindustrialcontrolmethodsc

8、anbeusedtocontrolthesuperheat;proportionalandintegralcontrol(PI),proportional,integralandderivativecontrol(PID),andalsorecentlyfuzzycontrol.Theuseoffuzzylogiccontrolforindustrialappli-cationshasbeenwidelydocu