Research on Influencing Factors of Heat Transfer Performance of Vertical Single U-Tube for Ground Source Heat Pump

Abstract

The heat transfer performance of the buried heat exchanger is a key factor affecting the efficiency of the ground source heat pump. In this paper, the heat transfer model of the vertical single U-type heat exchanger is first established under the condition of variable heat flow to make it closer to the actual operating conditions, for simplicity The calculation process and the calculation time are saved. The boundary element method is used to analyze the heat resistance of the buried heat exchanger, and then the numerical simulation software is compiled to simulate the heat transfer performance of the buried heat exchanger. The results of the study show that the soil temperature changes within a range of 1.5m from the buried tube heat exchanger. The hole spacing of the buried tube heat exchanger cannot be less than 4m in practical applications; when the soil thermal conductivity increases by 25%, The heat transfer per unit depth of the buried tube heat exchanger increases by 14.8%; When the diameter of the drill hole is increased from 160mm to 300mm, the heat transfer per unit depth of the hole increases by 8.2%.