软土地区竖直地埋管换热器参数与换热性能分析

Analysis on the design parameter and performance of vertical ground heat exchanger in soft clay area

地埋管换热器是土壤源热泵系统的关键部件,选择合理的设计参数是对土壤源热泵系统工程进行优化设计的基础。依托上海市典型地质条件建立单U垂直地埋管换热器三维非稳态传热模型,分别分析了上海市地质条件、换热器结构、循环流体、运行模式等因素对地埋管换热器换热性能的影响,并通过回归分析得到地埋管换热器换热效率的变化率与主要影响因素的关系式,使各影响因素的敏感度得到量化,对于影响地埋管换热器换热性能的参数,根据影响程度由大到小依次为循环水平均温度、原始地温、换热孔深度、岩土体导热系数、回填料导热系数。研究结果为土壤源热泵系统的实际应用提供参考。

Ground heat exchanger（GHE） is the key component of ground source heat pump（GSHP）system. Resonable design parameters of GHE is the foundation of optimum design of GSHP project.Three dimensional non-state heat transfer model of single U-tube ground heat exchanger was established base on the typical geological condition in Shanghai. This paper analyses the influences on heat transfer performance by such factor as geological condition, heat exchanger structure, circulating fluid, operation mode et al. The linear regression techniques are used to obtain the regression equations of the heat exchange power with the main parameters, and the separate effects of these factors was quantified. The degree of influence of these influence factors from large to small in order is the average temperature of circulating water, the original soil temperature, the depth of hole, the thermal conductivity of soil and the thermal conductivity of backfill. The results provided an reference for the actual ground-source heat pump system projects.