Thermal Response Test And Numerical Simulation Of Vertical Heat Exchanger Of Ground Source Heat Pump

The heat exchanger of ground source heat pump system has been recognized as a energy efficientsystem for space heating and cooling in residential and commercial buildings. The size and heattransfer performance of ground heat exchanger directly concerns the initial cost and efficient of theheat exchanger of ground source heat pump system.For requirements of heat exchanger of ground source heat pump, a ground thermal response testis done to obtain the complete and accurate data of soil at Youth Olympic village of Nanjing.Based on the available experimental data, two full-scale3D numerical models for single U-tubeand double U-tube ground heat exchanger are set up. By comparing the experimental values withthermal response test result, verify the accuracy of the numerical simulation. There are many factorsinfluencing the heat transfer performance of ground source heat pump. Based on the numerical model,the influence factors on the heat transfer quantity of single U-tube is analyzed, and the differencesbetween two kinds of the ground source heat pump are discussed.The quantity ground temperature around the heat exchanger is a basic condition of ground sourceheat pump to acquire high efficiency. The groundwater advection is favorable to strengthen the heattransfer in the heat exchanger of ground source heat pump. According to the actual layout of thelong-term monitoring station holes, a2D numerical single-well model is set up and the groundwateradvection can be taken into account. Compare the experimental values with thermal response testresult to verify the accuracy of the numerical simulation. It is shown that the heat piled up in groundcan be decreased evidently by groundwater advection. The problem of heat piled up must be takeninto account when the groundwater advection velocity is less than10-6m/s.In order to study the ground temperature change in some years, a2D numerical heat exchangergroup model is set up according to actual project. When the system operating in unidirectional andcontinuous mode, the problem of heat piled up is studied based on the bidirectional and discontinuousmodeThe research in this thesis can provide a theoretical base for the design of the heat exchanger ofground source heat pump system and application to enhance the efficiency and economy.