The influence of groundwater seepage on ground heat exchange

In order to determine whether the groundwater seepage has an impact on the ground heat exchanger in thermal efficiency, a three-dimensional coupling thermal seepage model of the vertical u-tube ground heat exchanger was established. The standard κ-ε turbulence model was used inside the pipe and the porous media model was used outside the pipe. The heat transfer process was simulated by the FLUENT software in summer cooling condition. By the simulation results, the outlet temperature of the seepage model of heat exchanger is lower than the no-seepage model of heat exchanger, and with the seepage velocity increasing, the heat exchanger´s outlet temperature is lower, soil temperature field around the heat exchanger offset more serious. Therefore, the groundwater seepage of ground heat exchanger has certain influence in the thermal efficiency, the greater the seepage velocity, the higher the efficiency of heat exchanger. What´s more, the seepage direction will affect the distribution of the soil temperature field around the heat exchanger.