地源热泵地理埋管换热器不同运行模式实验.研究与模拟

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1、摘要differentflowrateandoperatingmodewereappliedforexperimentaltesting，accordingtothedifferentoperatingmode，threephasesofexperimentaltestinghadbeendivided，theywereall—daycontinuousoperation，daytimeoperationonly,andall—dayintermittentoperation．All—daycontinuousoperationmodewasseparatedintothreep

2、artsbasedontheflowrateof0．65m3／h，0．7m3／h，and0．8m3／h．Theresultsshowed，thebestaveragequalityofheattransferpermeterofboreholeandcoefficientofsystemperformanceare53．66W／mand3．91W／Wrespectivelyatthe0．8m3／hflowrate．So0．8m3／hwaschosenastheexcellentflowrateoftheexperimentaltesting，intermofdifferentra

3、tioofon—offtime，daytimeoperationonly,anliall-dayintermittentoperationweredeployed．Itfoundthatthequalityofheattransferbecameincreasinglyreducedalongwiththetimeprolonged．Underthesamecondition，thesystemperformanceofintermittentoperationisbetterthantheall—daycontinuousoperation，thedaytimeoperatio

4、nonlywasthebestamongthem，theaveragequalityofheattransferpermeterofboreholeandcoefficientofsystemperformanceare55．14W／mand3．96W／Wrespectively．Finally,basedonheattransfermechanismofU-tubeunderground，forasingleborehole，atransientone—dimensionalline-sourcemodeloutsideboreholeandquasi·-three--dime

5、nsionalsteady-·statemodelinsideboreholewerepresented．InviewofdifferentoperationmodeofGSHPVI南京师范大学硕士学位论文systemwouldcausetime—varyingloads，heatpulseanalysistheorywasused．Underthecontinuousoperationmode，aseriousofcontinuousrectangularheatpulseswasapproximatedbyaseriousstepheatpulse；undertheinter

6、mittentoperationmode，aperiodofcyclicheatingofthegroundwasapproximatedbythesummationofacontinuousmeanloadandasingleheatingpulse．Then，superpositionwasappliedtodealwithsuchvariableanddiscontinuousloads．Combinedwiththermalresistanceinsideborehole，theinlet&outletwatertemperatureofU-tubeexchangerco

7、uldbesimulated．Comparedthesimulatedvalueswithexperimentalresults，theaverageabsoluteerrorandaveragerelativeerrorisSOlittle．Thiscomparisonsuggestedthemodelinghashighaccuracyandrationality,andcanbeusedtoinstructpeopletodesign，simulatetheU—tubehe