| FLUENT is used to simulate heat transfer of U-tube heat exchanger and provide somereferences for engineering design of U-tube heat exchanger, the study focuses on theinfluence of U-tube heat exchanger heat transferring and efficiency of flow velocity, inletwater temperature, U-tube diameter and depth.Firstly, gambit is used to establish a three-dimensional model and the model consistentwith the actual GSHP U-tube heat exchanger model. Fluent is used to calculate heat transferbetween soil and U-tube heat exchanger, the results agree well to the experimental data,which verifies the reliability of the model. Meanwhile, analysis of the soil, water and backfilltemperature variation during the operation of the U-tube heat exchanger, increasing flowvelocity, inlet water temperature and U-tube diameter, reducing the drilling depth willincrease the soil temperature around the U-tube heat exchanger, providing variation of soiltemperature during operation of U-tube heat exchanger.Secondly, obtaining variation of average quantity of heat per meter and pressure droploss, pointing out the way to improve heat transferring and reduce energy loss. In order toanalysis energy saving of U-tube heat exchanger more clearly, customizing U-tube groundheat exchanger efficiency formula, increasing the water temperature, reducing drilling depthand the flow velocity can improve the efficiency of the U-tube heat exchanger, among thesefactors flow velocity has a great impact on U-tube heat exchanger efficiency, which shouldbe less than0.3m/s if meeting the heat demand, in the same flow rate, bigger diameter canimprove the efficiency of heat exchanger, at different flow velocity, the efficiency turns onfluctuations in diameter. It needs to consider regional impaction in the application of U-tubeheat exchanger, in Beijing and Wuhan U-tube heat exchanger more efficient than inGuangzhou in the same condition, which provides references to energy saving design ofU-tube heat exchanger. |
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