地源热泵垂直u型埋管换热器不同运行模式的性能模拟与实验.研究

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1、theboreholewall：atransientone．dimensionalline．sourcemodeloutsideboreholeandquasi·three—dimensionalsteady—statemodelinsideborehole．Thencombinedwithtemperatureresponsetheoryconductedbypulseheatundercontinuousandintermittentoperationmode，amoreintegratedandpractical

2、modelwasestablished，thismodelconsideredmanyinfluencingfactors，suchsystemoperationmode，fluidvelocity,boreholedepth，tubetype，thermalpropertyofgroutandsoil，etc．Secondly,thepaperpresentedawholesummerexperimentalresultsforcoolingabout60metersboreholeindepthinstalleda

3、verticalU—tubeheatexchangerinShanghai．InordertostudyonheattransferperformanceofU-tube，severaldifferentflowvelocityandoperationmodewereappliedforexperimentaltesting，accordingtodifferentoperationmode，threephasesofexperimentaltestinghadbeendivided，theywereall—dayco

4、ntinuousoperation，daytimeoperationonly,andall-dayintermittentoperation．All—daycontinuousoperationmodewasseparatedintothreepartsbasedonflowvelocityof0．34m／s，0．37m／s，and0．42m／s．Theresultsshowedbestaveragequalityofheattransferpermeterofboreholeis73．66W／mat0．42m／sfl

5、owvelocity,itexceeded5．12W／mcomparedtoO．34m／s，anditexceeded3．51W／mcomparedto0．37m／s．So0．42m／swaschosenasexcellentflowvelocityofexperimentaltesting，intermofdifferentratioofon-offtime，daytimeoperationonly,andall-dayintermittentoperationweredeployed．Itfoundthat，und

6、erthesamecondition，thesystemperformanceofintermittentoperationisbetterthanthea11．daycontinuousoperation，thedaytimeoperationonlywasthebestamongthem，theaveragequali够ofheattransferpermeterofboreholeandcoefficientofsystemperformancewere75。14W／m．Finally,theheattransf

7、ermodelestablishedbythepaperwasverifiedbytheexperimentaldate．Wheninputstatedparameters，theinlet&outletwatertemperatureofU—tubeexchangercouldbesimulated．Comparedthesimulatedvalueswithexperimentalresults，averageabsoluteerrorwas0．6446。C，andaveragerelativeerroris1．8

8、4％．Thiscomparisonsuggestedthemodelhashighaccuracyandrationality．Inaddition，theU．tubeheatexchanger’Sheattransferperformanceundercontinuousandintermittentoperationmodew