Ground heat exchangers (GHE) have been extensively studied in the past decades in order to optimize the heat exchange with the ground in particular when they are coupled with a building equipped with heat pumps. Ground heat exchangers can be categorized in several ways: vertical, horizontal or even pile heat exchangers. In the special case of vertical heat exchangers, the single U-tube and double U-tube are the most common configurations but coaxial boreholes have drawn attention in recent years. This paper provides some new insight on this configuration based on analytical models that were validated with numerical simulations. The outcome of the study gives new comprehension on the effective borehole resistance associated with coaxial configurations in ground heat exchangers design.

地热交换器 (GHE) 在过去的几十年中得到了广泛的研究，以优化与地面的热交换，特别是当它们与配备热泵的建筑物结合使用时。地埋式换热器可以按多种方式分类：立式、卧式甚至是桩式换热器。在立式换热器的特殊情况下，单U型管和双U型管是最常见的配置，但同轴钻孔近年来引起了人们的关注。本文基于经过数值模拟验证的分析模型，对这种配置提供了一些新见解。研究结果使人们对与地下换热器设计中的同轴配置相关的有效钻孔阻力有了新的理解。