基于负荷自适应分配的地埋管换热器传热分析

Heat Transfer Analysis of Ground Heat Exchanger Based on Self-adaption Load Distribution Method

本文采用自适应负荷法分析地埋管换热器长期运行时各埋管换热量、进口水温及土壤温度分布情况,并与目前广泛应用的均分负荷法进行对比。自适应负荷法计算结果表明各埋管换热量并不相同,呈中心区域低周边区域高的分布趋势,长期运行后土壤温度分布仍较为均匀,中心区域土壤冷热量累积较周边区域并不十分明显;均分负荷法采用各埋管换热量相同的假设与实际不符,导致其计算的各埋管进口水温明显不同的结果与实际不符。采用均分负荷法计算结果显示埋管中心区域冷热量累积严重,这与自适应负荷法得到的结果存在显著差异。分析认为,自适应负荷法计算结果更可信。

In this paper,the self-adaption load distribution method(SLDM)is used to analyze the thermal loads and inlet water temperature of each buried tube of ground heat exchangers(GHE),the soil temperature distribution during long-term operation and the results were compared with those obtained based on the mean load distribution method(MLDM)which is widely used presently.The results calculated by the SLDM show that the thermal loads of different buried pipe are not same,and those of the pipes in the central zone are relatively low while those of the pipes in the side area are relatively high.Even after long-term operation,the soil temperature distribution is still relatively uniform,and the thermal accumulation in the central area is not obviously serious compared with that in the side area.The MLDM assumed that all buried pipes have the same thermal loads which is obviously deviated from the real situation,therefore,the calculated result that the inlet temperatures of buried pipes by MLDM are not same is not in accordance with the actual case.The MLDM results show that thermal accumulation in the central area is quite serious which is different from that obtained by the SLDM.However,analysis shows that the results obtained by SLDM are more reliable.