Simulation And Experiment Research On Ground Temperature Field Around Heat Exchanger Of Ground Source Heat Pump

Ground temperature field around ground heat exchanger could visually reflect thesoil thermal property and heat exchange effect of ground heat exchanger, therefore, theground temperature field around the vertical double-U heat exchanger is studied bycombining engineering experiment and simulation method, to explore the factorsinfluencing the ground temperature field around the vertical double-U heat exchanger.To explore the factors affecting the ground temperature field around heat exchangerand parameters needed in model solving, the transient model of ground temperature fieldaround the vertical double-U heat exchanger is established first. Next, a experimentplatform on ground temperature field around ground heat exchanger is built to obtainsoil thermophysical parameters and initial ground temperature field for simulation, thenoperate heat pump experiment system to acquire the changing data of ground heatexchanger, such as inlet water temperature, outlet water temperature, flow rate andground temperature field change. Thirdly, Matlab software is utilized to simulate theground temperature field change around the double-U heat exchanger, then simulationresults and experimental data are compared to verify the reliability of the model. Finally,the model simulation is utilized to analyze the main factors of the ground temperaturefield.The experiments and simulation results show that.1) Soil moisture content changes obviously along with dePth, and presents a certainrandomness.2) The soil initial temperature measurement shows that：within0~50m, the soilinitial temperature is first increased and then gradually decline.3) The larger the flow rate of ground heat exchanger, the soil (around ground heatexchanger) temperature decrease becomes larger, but when the flow rate increased to acertain degreee, this decrease begains to change slowly.4) The lower the inlet temperature of ground heat exchanger, the soil (aroundground heat exchanger) temperature decrease becomes larger, and the the radius of thethermal effect becomes further.5) Near the heat exchanger surface, the larger the soil thermal conductivity, the soiltemperature decrease becomes smaller; but at the distant of heat exchanger, the larger thesoil thermal conductivity, the soil temperature decrease becomes larger.6) As the heat capacity of the soil increasing, the decrease range and the radius ofthe thermal effect becomes smaller;7) The soil thermal conductivity stratification hardly affects the heat exchangebetween ground heat exchanger and soil, but the effect of heat capacity stratification onheat exchang capacity is much more significant.