不同回填材料下地埋管换热器性能的实验研究
Experimental research on the performance of geothermal heat exchangers for different backfill materials
摘要：
实验研究了原土（粉细砂）和中粗砂回填条件下双U形地埋管换热器的传热性能，获得了换热量随管内流体平均温度的实测变化曲线。结果表明，换热量与流体平均温度之间呈线性变化规律，在地埋换热器工作温度范围内，中粗砂回填时的换热量比粉细砂回填时高约10%（取热工况）和6%（排热工况）。建议在选择回填材料时，应在考虑其对地埋管换热器传热特性影响的基础上，进一步考虑其经济性。
Abstract：
Makes an experiment on the heat transfer performance of double U-shaped geothermal heat exchangers(GHE) under the backfill materials of fine sand and medium-coarse sand, and obtains the variation curve of the underground heat transfer rate with the average in-tube fluid temperature. Experimental results show that there is a linear relationship between the underground heat transfer rate and the average fluid temperature. Within the normal operation temperature range of GHE, the underground heat transfer rate for fine sand is 10% for heat injection mode and 6% for heat extraction mode higher than that of medium-coarse sand. Suggests that selection of the backfill materials should base on both its influences on the heat transfer performance of GHE and its economic efficiency.
Keywords:ground-source heat pump, geothermal heat exchanger, heat transfer performance, backfill material