The Research On Underground Heat Exchanger For Ground Source Heat Pump

The development of heat pump technology attracts the world attention because it is as one kind of new energy technology. Using the heat pump equipment to save the energy, not only is advantageous to the energy comprehensive utilization, but also can effectively reduces the air pollution. It can be able to both heating and refrigerating, so the equipment utilization rate is high. It proposes the main content this article studies is heat transfer analysis, modeling and design method about the underground heat exchanger which is suits the actual need.Second chapter in view of the underground heat exchanger, introduces the material, classification and the pipe diameter of the underground heat exchanger, analyses the performance influence factors of the underground heat exchanger. It has carried on the introduction of heat transfer models of underground heat exchanger which is commonly used one by one.The underground heat exchanger is the important constituent of the source heat pump system. Reasonable form, correct design and answering the purpose to the entire GSHP system is significant. So it is very necessary to research the underground heat exchanger. Because running time is long and the heat transfer space is big, the heat transfer process of the underground heat exchanger is complex and it is a unstable heat transfer process. In the third chapter, we can obtain the soil temperature field expression under the different depth and the different time through carrying on the analysis of the temperature field of the symmetry semi-infinite big object under the periodic variation boundary condition. In order to simplify the computation and be advantageous for the theoretical analysis, the soil partial heat transfer analysis uses the unstable condition heat transfer model analysis research regarding the drill hole outside. The commonly used simplification model may sum up as following several kinds of forms: Infinite line heat source model; Infinite long column heat source model; Limited long-line heat source model. The interior size and the calorific capacity of the borehole are much smaller, moreover the temperature change is slow, so usually we can neglect the influence of calorific capacity but to consider according to the heat transfer in steady state process, thus we can establish one-dimensional and the two-dimensional thermal resistance model in the borehole.