Vertical Buried Tube Of Heat Exchanger Heat Transfer Numerical Simulation Research

In the 21st century, with the increasing scarcity of the earth’s traditional energy, energy has become a growing concern topic. Due to its high efficiency and energy saving, Ground Source Heat Pump is gradually recognized by people and the technology has been widely used. Underground heat exchanger is one of the most key point of ground source heat pump technology, the heat exchanger size of its heat capacity directly affects the unit’s efficiency.This paper first describes the research status of ground source heat pump at home and abroad, development, as well as the surrounding soil physical parameters of ground source heat pumps. For vertical U-shaped ground heat exchanger, most of the buried pipes is located in the saturated zone soil, ground heat exchanger performance will be mostly affected by the groundwater seepage, to form a heat infiltration coupled transfer process. On the basis of the theory that the soil is treated as porous media, to make the appropriate simply, then establish the mathematical models of the vertical U-shaped ground heat exchanger under the role of heat infiltration coupled to simulate the change heat of ground heat exchanger and soil as well as the impact of the around soil’s temperature. This paper uses pre-processor modeling software GAMBIT to establish a physical model, and then through the software of FLUNT make numerical simulation and post-processing.This paper studies the impact of groundwater flow on buried single vertical U-shaped heat exchanger and simulated it. Analyzes the impact of groundwater flow on the surrounding soil, and the impacts of add antifreeze at different concentrations (ethylene glycol) to the tube and soil’s axial flow stratification on ground heat exchanger. The simulation results show that the seepage of groundwater is in favor of ground heat change, but also conducive to weaken the cold accumulation caused by the imbalance of ground heat exchanger absorbs heat; in the summer, the impact of adding antifreeze on the system heat can be ignored; in the winter, the heating capacity of the heat pump system will decreased with the antifreeze (ethylene glycol) concentration’s increasing. The greater concentration of the antifreeze (ethylene glycol) and the greater decay of heat change of underground pipe.On the basis of single U-shapes heat exchanger, to establish three-dimensional thermal penetration coupled heat transfer of buried underground pipe nest. Simulating the impact of different groundwater flow direction, different ground heat spacing and different ground heat pipe arrangement on the temperature around the ground heat pipes, to offer theoretical reference of the practical application, also benefit from the development of ground source heat pump.