地温未恢复时热响应试验的线热源叠加法

Line-source superposition method of thermal response test without ground temperature recovery

针对热响应试验中2次测试间地温未恢复的情况,提出了一种基于线热源叠加法计算岩土平均导热系数的方法,根据时间函数和流体平均温度之间的线性关系计算得到岩土导热系数。建立了地埋管换热器的线热源模型,对3个钻孔分别依次进行了高、低2种输入功率的热响应测试,2次测试间地温未完全恢复至初始地温。分别采用常规线热源法和线热源叠加法对第2次测试结果进行分析,采用线热源叠加法2次测试结果偏差明显减小。

For the condition that the ground temperature does not recover between the two successive tests in thermal response test （TRT）, presents a calculation method of average heat conduction coefficient of soil based on the line-source superposition method, in which calculates the heat conduction coefficient of soil according to the linear relationship between time function and average fluid temperature. Establishes the line-source model for ground heat exchangers. Conducts the TRTs in three different boreholes with two different heating powers, respectively, and the ground temperature does not recover between the two successive tests. Analyses the second TRT data by using both of the conventional line-source method and the new method. The comparison shows that the results based on the superrposition method have enough accuracy.