地源热泵地下岩土热物性现场热响应测试方法研究

Study on the Method of in-situ Thermal Response Test for the Determination of Ground Thermal Properties in Ground Source Heat Pump

为了准确决定埋管现场岩土热物性值,建立了一套现场热响应测试装置,详细分析了测试原理、装置流程与数据处理方法,并应用所建装置与数据处理模型对一地源热泵工程进行了实测与分析,获得工程所在地土壤原始平均温度为17.7～17.9℃,土壤等效导热系数为1.78W/(m.K),等效容积比热容为2580kJ/(m3.K),单位长度钻孔热阻为0.163(m.K)/W。同时,为了提高测试精度,必须采用稳压电源及做好外露管道保温措施,数据处理上应舍弃测试初期10h的测试数据。试验验证表明,本文所建立的地下岩土热物性测试装置与分析模型是可行的,可应用于实际地源热泵工程中地下岩土热物性的测试。

In order to determine accurately the in-situ ground thermal properties,an experimental apparatus of thermal response test was built to measure the temperature response,the test pinciple,device diagram and data processing method were introduced in detail.Based on the device and data precessing model,a practical test project of ground source heat pump has been also performed,the test results indicate that the ground initial temperature is about 17.7~17.9℃,the effective thermal conductivity and volumetric specific heat are 1.78W/（m·K） and 2580 kJ/（m3·K） respectively,and the borehole thermal resistance is 0.163（m·K）/W.At the same time,the voltage stabilizer and thermal insulation for exposed pipe should be used to improve test accuracy.The test data after 10 h should be selected to proceed for obtaining the results.The experimental validation shows that the thermal response experimental apparatus and the analysis model proposed in this paper are feasible and can be used in the practical ground source heat pump project for determination of ground thermal properties.