地源热泵垂直埋管换热器地下热阻及管长的分析

讨论了地源热泵垂直埋管换热器传热过程及其数学模型，引入热阻的概念，将埋管换热器管内流体与土壤的传热过程分为钻孔内和钻孔外两部分。阐述了利用传统的线源和柱源理论求解钻孔外热阻的方法，并结合实例对影响埋管换热器管长的因素进行了对比分析，可供工程设计计算使用。

Thermal resistance and tube length of a vertical borehole in ground-source heat pumps

The heat transfer process and mathematic models of the boreholes in vertical ground heat exchangers is discussed. A resistance concept is inducted in order to divide the heat transfer process between the fluid and soil into two parts, one is inside the borehole, and the other is outside. A method using line-source and cylinder theory to count the resistance outside the borehole is introduced. Calculations on practical cases are carried out to show the influence factors to tube length for engineering applications.