ASHRAE.4521-2002 In Situ Measurement of Ground Thermal Conductivity

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1、4521InSituMeasurementofGroundThermalConductivity:ADutchPerspectiveHenkJ.L.Witte,Ph.D.GuusJ.vanGelderJeffreyD.Spitler,Ph.D.,P.E.MemberASHRAEABSTRACTWewilldiscussresultsofanextensivetest,includingahigh-resolutiontimeseriesofexperimentaldata,detailedDeterminationoftheground’sthermalconductivi

2、tyisageologicaldescriptionsandconepenetrationtests,additionalsignificantchallengefacingdesignersofground-sourceheattemperaturemeasurementsmadeinobservationwells,andpump(GSHP)systemsappliedincommercialbuildings.Theindependentmeasurementsofthermalconductivity.Severalgroundheatexchangersizean

3、dcostarehighlydependentoncaveatsofthemethod,aswellaspossiblesolutions,willbethegroundthermalproperties.Inordertobeabletopredictpresented.groundthermalproperties,anexperimentalapparatushasbeenbuiltcapableofimposingaheatinjectionorheatextrac-Thegroundthermalpropertiesareamongthemostcriti-tio

4、npulseonatestboreholeandmeasuringitstemperaturecalparametersingroundheatexchangerdesign,andtheyareresponse.Analysisofadetailedinsitutestusingalinesourceamongthemostdifficulttoquantifywithsufficientaccuracyapproachandbootstrapuncertaintyanalysisispresented.orconfidence.Methodsforestimatingt

5、hethermalpropertiesResultsarecomparedwitha“traditionalestimate”basedonofthegroundincludeusingvaluesfromliterature,conductingadetailedgeologicaldescriptionandwithresultsoflabora-laboratoryexperimentsonsoil/rocksamples,andperformingtorymeasurements.Theseresultsarealsocomparedtothoseinsitutes

6、ts.determinedusingparameterestimationinconjunctionwithatwo-dimensionalfinitevolumemodel.Usingliteraturevaluesrequirestheleasteffort,buttherangeofthermalconductivityvaluesreportedinliteratureisINTRODUCTIONoftenquitelarge,duetothefactthatlocalcircumstanceshaveabiginfluence.Moreover,thesegene

7、ralvaluesforspecificThispaperdescribesaninsitutestfacilitytomeasuretypesofsoil/rockneedtobetranslatedtoavaluerepresenta-groundthermalproperties.Incontrasttopreviouslydescribedtiveofthewholesoilprofile.Aprudentdesignwillusethefacilities,thisoneallowsbothheatinj