Influence on thermal response test by groundwater flow in vertical fractures in hard rock.pdf

《Influence on thermal response test by groundwater flow in vertical fractures in hard rock.pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、RenewableEnergy28(2003)22212238www.elsevier.com/locate/reneneInfluenceonthermalresponsetestbygroundwaterflowinverticalfracturesinhardrocka,∗bS.E.A.Gehlin,G.Hellstro¨maTheSwedishAssociationforHVACEngineers,Box5501,SE-11485Stockholm,SwedenbDepartmentofMathematicalPhysics,LundTechnicalUniversity

2、,Box118,SE-22100Lund,SwedenReceived28December2002;accepted26March2003AbstractInthispaperdifferentapproachestogroundwaterflowanditseffectinthevicinityofaboreholegroundheatexchangerarediscussed.Thecommonassumptionthatgroundwaterflowinhardrockmaybemodelledasahomogeneousflowinamediumwithaneffectiv

3、eporosityisconfrontedandmodelsforheattransferduetogroundwaterflowinfracturesandfracturezonesarepresentedespeciallyfromathermalresponsetestpointofview.Theresultsindicatethatgroundwaterflowinfracturesevenatrelativelylowspecificflowratesmaycausesignifi-cantlyenhancedheattransfer,althoughacontinuuma

4、pproachwiththesamebasicassumptionswouldsuggestotherwise.Ó2003ElsevierScienceLtd.Allrightsreserved.Keywords:Groundheatexchanger;Borehole;Groundwater;Thermalresponsetest;Thermalconductivity1.IntroductionTheinfluenceofgroundwaterflowontheperformanceofboreholeheatexchangershasbeenatopicofdiscussi

5、on.Fieldobservationsindicatethatgroundwaterinflu-encestheboreholeperformancebyincreasingtheheattransportsignificantly[15].Sometheoreticalstudieshavebeenpublishedonthesubject.[6],[7]and[3]presentmodelsfortheinfluenceofregionalgroundwaterflowbasedontheassumptionthat∗Correspondingauthor.Tel.:+46-8

6、-783-83-80;fax:+46-8-660-39-44.E-mailaddress:gehlin@siki.se(S.E.A.Gehlin).0960-1481/03/$-seefrontmatterÓ2003ElsevierScienceLtd.Allrightsreserved.doi:10.1016/S0960-1481(03)00128-92222S.E.A.Gehlin,G.Hellstro¨m/RenewableEnergy28(2003)2221–2238thenaturalgroundwatermovementisreasonablyhomogeneou

7、slyspreadoverthegroundvolume.Thisapplieswellonhomogeneousandporousgroundmaterial.Eskilson[6]andClaessonandHellstro¨m[7]usethelinesourcetheoryformodellingthegroundwatereffectonasingleverticalborehole.Theyconcludethatundernormalconditions,theinfluenceofregi