重庆地区竖直双U形地埋管换热器周围土壤温度恢复性能研究
Study on soil temperature restoration around vertical double U-type ground heat exchanger in Chongqing
摘要：
通过对重庆某实际项目地埋管换热器周围土壤温度进行全年连续监测，研究分析了不同回填材料及回水管保温与否对地埋管换热器周围土壤的温度恢复及热累积现象的影响。测试结果表明：在1个夏季典型日地埋管换热器周围土壤产生温升0.26～0.94 ℃，1个运行周期内产生温升0.10～0.39 ℃，均随着深度的增加而减弱；夏季过渡期内，除距自然地表1.5 m处土壤温度随天气变化外，其余各深度测点的土壤温度恢复主要集中在前2 d，温降约为1.5～2 ℃/d。恢复时间短、回填材料导热系数小及地埋管回水管保温均对土壤温度恢复产生不利影响，但在较长的恢复时间内，其影响不显著。
Abstract：
Tests continuously the soil temperature around the ground heat exchanger of a demonstration building in Chongqing for the whole year, analyses the influences of the different backfill materials and the increased insulation resistance of return water pipe on the temperature restoration and the thermal accumulation effect of the soil around the ground heat exchanger. The test results show that the soil temperature around the ground heat exchanger rises by 0.26 to 0.94 ℃ in a typical day in summer and by 0.10 to 0.39 ℃ in an operation cycle, and they are all gradually weakened with the increase of depth. In the transition season, except that the soil temperature in depth of 1.5 m changes with the weather, the soil temperature recovers mainly concentrate in first two days before with the speed of 1.5 to 2 ℃ per day. The smaller coefficient of thermal conductivity of the backfill material and return water pipe thermal insulation are harmful to the soil restoration in a short time. But this effect is weakened as the time goes on.
Keywords:ground-source heat pump, ground heat exchanger, soil temperature restoration, heat accumulation phenomenon, backfill material, return water pipe thermal insulation