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

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。

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.