Study On The System Performance Of U-type Ground Source Heat Pump And Ground Temperature Field

This paper presents a theoretical and experimental investigation of the U-pile heat exchanger. On the basis of the analysis of three ground heat exchanger models and its performance of heat transfer, research is carried on the U-type underground heat exchangers. And the theoretical model, which is composed of one-dimension heat transfer equation in the vertical direction and two-dimension heat transfer equation in the horizontal direction, is established to describe the heat transfer between the underground heat exchangers and soil. Calculates and analyses the temperature distribution of the pile surface and the soil around it. And comparisons are made between the theoretical results and experimental ones. In addition, investigation is carried on performance of heat transfer among the U-pile underground heat pumps. Through calculation and analysis, effects of different kinds of soil, various thermal conductivities between two legs on the heat transfer of underground heat exchangers are discussed. Based on the research, experiments are carried on GSHP at Meijiang District in Tianjin in winter and summer. The coefficient of performance and characteristics of the GCHP cycle are analyzed and summarized. Meanwhile, the economical research of the GSHP at Meijiang is analyzed. The result indicates that the GSHP system is much more economical. And the comparisons show that GSHP is an efficient and effect means for buildings.