Heat Transfer Research And Designing Calculation On Vertical Single-U Type Heat Exchanger Of Ground Source Heat Pump

Ground source heat pump (GSHP) air conditioning systems utilize ground soil as a heat source/sink, achieve heat transfer between the ground soil and a working fluid (water or antifreeze solution) circulating in a closed loop buried in the ground. Compared to other conventional alternatives, the ground source heat pump system makes full use of renewable energy, and boasts the features of protecting the environment and reducing electric power consumption. It has been applied in Europe and American for a few decades. In recent years the technology has been paid atention to also in China, and a few GSHP pilot projects have been completed here. However, researches on design of the geothermal heat exchanger (GHE), performance predictions of the GSHP systems and system optimization are far from adequate. Besides, no national standards and criteria are promulgated for the GSHP systems. This situation impedes its application.For the sake of can betterly analyse the heat transfer process of the underground heat exchanger and can betterly couple the heat exchanger and the underground heat pump machine, in order to design the reasonable and the valid underground heat exchanger, on the basis of analyzing the available heat transfer models, the heat transfer model of exchanger in this article will be divided into two parts by the hole wall: the heat transfer model outside the hole wall and the transfer model inside the hole wall. theheat transfer model outside the hole is the limited long column source model which is founded on the basis of the limited long line source model. This model has made up the shortage of the line source model and the infinite long column source model. The heat transfer model inside the hole wall adopt the advanced quasi-3D heat transfer model. Solve the two models by a series of theories methods and verify the credibility of the theories solution by limited unit method.The purpose of this article is to design the reasonable and valid underground heat exchanger. So the heat transfer research on heat exchanger must couple the running situation of the heat pump machine. This article draw up a procedure to calculate the length of the U-type pipes.The Ground-Source Heat pump is a fresh domain in china and has a promising developing.