Three-dimensional Dynamic Mumerical Analysis Of Meters Deep Vertical Heat Exchanger In Ground-source Heat Pump

Energy and the environmental problem are the major issues faced by the world today, how to make better use of limited energy, how to protect the environment effectively, has become the focus of academic and technical study of the world. Ground source heat pump system is widely used because of its energy-efficient, environmental benefits significant. In addition, in view of the characteristics of China's crowded, vertical U-tube heat exchanger of ground source heat pump system is more suitable for China's national conditions. So this article focuses on vertical U-tube heat transfer performance of heat exchanger.The subject is greatly supported by the special fund "Research of the heat transfer performance of the heat exchangers used in Ground-source heat pump in Xi'an", which is the technology and science project in Xi'an.From the characteristics of the ground-source heat pump, combined with the development situation of ground-source heat pump in domestic and foreign, the theories of ground source heat pump are expounded in this article, which provides theoretical support for in-depth study. Additionaly, according to the internal structure of the underground soil in Xi'an, thermal physical parameters of the soil are calculated, which will be used in the simulation. And then the model which according to actual project 1:1 to be established by the Gambit, the vertical U-tube ground-source heat pump heat exchanger buried three dimensional heat transfer model for soil temperature field around, and the calculation equation is discrete by dividing the model grid for more accurate simulations.In the simulation process, the Fluent is used to simulate the following conditions:under the condition of steady and unsteady simulation. And the steady-state condition in summer and winter in steady-state conditions are included in the steady-state, all of this is in order to establish a model for authentication, and then simulate the more complex calculation such as non-steady-state simulation. The Calculation results are ideal, indicating that the model can be used for non-steady-state calculation. The continuous operating conditions and intermittent operating conditions are included in the calculation of non-steady-state, each condition's calculation will be based on the different time and different conditions, modify the conditions and parameters in the model for the varieties situation. In non-steady-state calculation, the heat exchange between the buried U-tube heat exchanger with the surrounding soil, and the soil temperature field recovery situation after the end of the heat pump is tunning are focused on by the analysis of results. So a theoretical basis about the ground-source pump system is provided for the project, and making people have a better understanding of the heat transfer performance in actual operation in the process.