Study on temperature field around heat pipe underground based on line heat source theory

Low and moderate geothermal resource can be found in most areas of the world and heat pump system as an efficient device to utilize the geothermal is prevalent. It is important to know temperature field around the heat-exchange pipelines for efficient conversion and use of geothermal energy. The temperature distribution around the heat pipe underground was studied by the heat source method in the paper. Based on the method, every heat pipe could be supposed as a heat source that would produce a corresponding temperature field, and the total temperature underground could be the superposition of every temperature- field. The temperature fields around heat pipes were given in the paper in different containing water rate of the soil, gap rate of the soil and different disposal of heat pipes. It would be beneficial for design and better operation of the heat pipe system underground to use geothermal resource.

► Temperature of soil increases faster at the high containing water rate ϕ.
► Temperature of soil decreases with increasing of gap rate ɛ.
► It needed to be taken into account of the heat pipe arrangement and density of heat pipe arrangement.