Investigation And Experiment On U-Type Underground Heat Exchanger Of Ground Source Heat Pump

Due to its high efficiency and energy saving, the benefits of Ground Source Heat Pump(GSHP) is gradually recognized by people. Based on 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. During the calculation of two-dimension heat transfer, each polar coordinate is set up to generate numerical grids for each of two legs of vertical ground loop heat exchangers, calculate each one, and then synthesize the two results to obtain the influence of the two. In addition, investigation is carried on performance of heat transfer among the U-type underground heat pumps. Through calculation and analysis, effects of different kinds of soil, various flux in underground heat exchangers, thermal conductivities and distance 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 summer and winter. Finally comparisons are made between the theoretical results and experimental ones. And the validation of theoretical model is evaluated. Meanwhile, the cooling load of the GSHP at Meijiang in summer is calculated and analyzed. And the comparisons show that the GSHP are an efficient and effect means for buildings.