关键词: 动力机械工程, 储能技术, 套管式地下换热器, 耦合传热模型, 传热分析

Abstract: To analyze deeply the heat transfer of the coaxial tubes underground heat exchanger(UHE), a new model to couple the fluid flow in the collecting tubes and the heat transfer between the tubes and the soil was proposed based on the existing equivalent model. The heat transfer characteristics and the performance of the coaxial tubes UHE were analyzed by means of the finite element method. The effects of the size of the buried tubes and the flow velocity in the tube on the fluid temperature at the pipe outlet and the heat exchange per unit pipe. Moreover, the underground heat transfer characteristics under two kinds of the operation mode, the continuous operation mode and the variable load operation mode, were studied systematically. The effect of the control strategy on the operation of the UHE was discussed and a control strategy for the efficient operation of the UHE was presented.

Key words: power machinery and engineering, technology of energy storage, coaxial tubes underground heat exchanger, coupling model of heat transfer, heat transfer analysis