Simulation On Soil Temperature Field And Practical Engineering Case Study Of Ground Source Heat Pump System

Ground source heat pump system has been researched and applied in China for more than thirty years,more and more konwledges onground source heat pump are being obtained by researchers,as a result,ground source heat pump technology is also rapidly developing.In Tianjin,there are more than 30 heating or refrigeration demonstration projects untilizing ground soutce heat pump system.However,because of various reasons,these ground source heat pump systems are not in the ideal state.By making deep insight into these projects,one could find that causes of this situation including the unbalanced of heat input and heat output of the soil,unstanstardized operation,etc.However,there are many methods to solve these problems,including adjusting the amount of cold and heat input into the soil,expanding the distance between the wells and so on.According to the above problems,this paper took the ground source heat pump project locating at Baodi District of Tianjin as an example,the thermal response test was done before underground hole construction to determin thermal properties of soil,the single holeheat exchange per meter and well spacing.Meantime,the mathematical model of buried pipe heat exchanger heat transfer was established by using Gambit and Fluent software,based on which,the temperature field surrounding U-tube heat exchanger was simulated and the reasonable distribution of the buried hole was theoretically analyzed according to the geometric parameters of buried pipe and thermal responsive test parameters.By observing temperature of the test hole in winter and summer,the variation trend of underground temperature was confirmed,and the reasonability of the buried hole was further verified.Finally the changes in heat exchange amount in real condition and the performance of in the operation cycle was analyzed,and the reasonable operation method of the system was analyzed.The conclusions mentioned above could serve as the basis for the operation of other ground source heat pump systems in the future.