Study On The Underground Heat Transfer Mechanism And The Test Model Of Ground Source Heat Pump

As a new technology of energy conservation and emission reduction, ground source heat pump of high-efficiency and green, has been widely applied to engineering practices in recent years. However, the use of water source heat pump unit-ground source heat pump system may lead to the setting of the ground, thus seriously threatening the security of people’s lives and properties, due to which there is little research on it and basically a blank. The design of buried tube heat exchanger of ground source heat pump system is mainly influenced by rock-soil thermal parameters which, however, gained by the existing test methods are not accurate due to a few factors, such as the complexity and high-uncertainty of underground rock soil medium and the limit of the test point of rock-soil thermal parameters, etc. Therefore, there are two problems need to be urgently solved: how to calculate the setting of the ground caused by ground source heat pump system to provide designers with reliable foundation; how to devise a means capable of testing as many rock-soil sample thermal parameters as possible for a limited time to provide reliable design parameters. A good solution to these two problems is of great project application value. This paper did the following studies on them:Firstly, the introduction of the existing pumping-settling model at home and abroad is made to testify its inapplicability to the study of the pumping-settling mechanism of water source heat pump unit-ground source heat pump system. Then analysis of the mechanism of ground setting because of the use of water source heat pump is made; and a numerical model of the energy consumption and ground subsidence of ground source heat pump system is built based on water source heat pump unit, by combining the existing pumping-settling model and the existing water source heat pump theory and employing the knowledge of hydrodynamics and thermo-aerodynamics to calculate the amount of ground subsidence caused by water source heat pump unit-ground source heat pump system. Finally, the empirical analysis of the project is made. The analysis testified the accuracy of ground subsidence calculation by energy consumption and ground subsidence model in this paper and is of great theoretical and project application value.Besides, there is construction of unit-ground source heat pump buried tube heat transfer numerical model. Then, through experiments and finite element simulation, how and why the heat is transferred in unit-ground source heat pump buried tube heat transfer are analyzed in order to theoretically support the design of thermo-physical property of soil testing apparatus with displacement function. Moreover, the finite element analysis proves the feasibility of the experiment, serving as a strong theoretical basis for the experiment in process.Inevitably, there are many deficiencies in this paper. In the energy consumption-settlement model, it just assumes under the simple conditions of single aquifer and Single well pumping, without considering the time factor. Also, it is not so flawless in the experiment of rock-soil thermal parameters testing as well as the combination of the theory in this study and the corresponding practice.