Study on soil temperature field around horizontal buried pipe of heat exchanger for ground-source heat pump

With the change of soil conductivity, the temperature field and the heat flow distributions for horizontal buried pipes of the heat exchanger for the GSHP were calculated and analyzed according to a new two-dimension model for the horizontal buried pipes. Then the conditions which related to heat transfer of the heat exchanger were presented, such as buried depths, pipe's diameter, pipe wall's thickness and pipe's material. The results show that when the soil conductivity increases form 1.1 W/(m·°C) to 2.5 W/(m·°C), the heat transfer of one meter length of pipe increases by 100.8%, and the temperature of the soil which is closer to the pipe changes more faster with soil conductivity. The heat transfers of the buried pipes are larger and more stable in the second stage than in the first layer underground. Bigger diameter and thinner wall thickness of pipes are helpful to increase the heat transfer of the buried pipe of the heat exchanger.