Effects of soil freezing on the ground heat exchanger performance

Develops a transient heat transfer model considering the soil freezing. With the finite volume method, discretizes the governing differential equations of the fluid, the pipe wall and the soil, and solves the soil freezing problem based on the sensible heat capacity method. The numerical calculating results indicate that the soil freezing region around the ground heat exchanger is small, but the heat conductivity of freezing soil increases largely, which is benefit to the soil heat transfer. When considering the effect of soil freezing, the outlet fluid temperature and the heat extracted from the ground are higher. High soil moisture content is benefit to the heat transfer, but the effect of soil freezing on the performance of ground heat exchanger is small with lower soil moisture content.