基于多极理论传热模型的垂直U型地埋管传热特性研究

地埋管循环介质出口温度不仅仅反映了地埋管的换热能力,同时极大地影响着热泵主机的运行效率,是地埋管换热过程的一个重要能效特性参数,可通过引入能效系数来反映。文基于地埋管轴向流动多极理论传热模型对不同的回填材料物性、支管间距、地埋管埋设深度、土壤物性、管内循环介质流速条件下地埋管传热过程进行动态模拟和分析,得出了各重要特性参数的变化对U型地埋管传热能效的影响规律,可为土壤源热泵地埋管换热器的设计提供参考。

Study on Heat Transfer Characteristic of Vertical U-shape Ground Heat Exchangers Based on Multiple Theory of Heat Transfer

The outlet temperature of cyclic medium through ground heat exchangers（GHEs） not only reflects heat transfer capacity of GHEs,but also greatly affects operational efficiency of heat pump units.It is an important characteristic parameter of heat transfer process for GHEs and can be denoted by introducing energy efficiency coefficient.Based on multiple theory model of heat transfer for GHEs in soil,a dynamic simulation is conducted to analyze the heat transfer process under different circumstances including backfill material properties,distance between tube legs,buried depth of ground heat exchangers,soil heat properties and flow velocity of cyclic medium.The influence of important characteristic parameters on the heat transfer performance of vertical U-shape GHEs can be thus achieved,which may provide references for ground source heat pump GHEs in practical designs.