Research On Ground Temperature Around Heat Exchanger Of Ground-Coupled Source Heat Pump

Ground-coupled source heat pump system (simplified named as GCSHP below) uses the geothermal resources underground. It can transfer the potential energy from the low temperature to the high temperature by inputting small quantity of highly potential energy such as electricity. In this way, it can provide both cooling and heating. In this paper, the ground temperature around the heat exchanger is studied by combine theoretical calculations and experiments on-site. The pt temperature seniors are set in different depth and different radius. In the heating, cooling and transition season, the change of ground temperature can be got. Based on the actual conditions, the semi-infinite object model can be established by modifying. Ignore the grout volumetric heat capacity and the heat is thought as effect on the wall of the well instantaneously. This theory can help to calculate and forecast the ground temperature around the heat exchanger.The research shows that the temperature of the ground is gradually rising with depth and The temperature gradient is about +0.03℃/m. The thermal influence radius of GCSHP is 2.5m in winter. But in summer it is more than that. The calculate results show that in summer the thermal influence radius of the heat exchanger in this project is 3.5m. Because of heat storage and the slow transfer of heat, the soil temperature does not reach the lowest at the end of the heating period but in the transition season. It will delay one to two months. Then the soil temperature recovers. It can be deduced that at the end of the system running in summer, the soil temperature will also rise. Because the heat transfer is more in summer than in winner, the recovery period will delay to more than two months. After four yeas the ground temperature rises obviously and is not conductive to heat transfer. The supplemental heat rejecter is needed.