The exact and rational design of the sewage fooled refrigerant evaporator and sewage condenser is critical for the safe and efficient operation of the direct untreated sewage source heat pump system (DSSHPS). Based on the flow resistance and heat exchange characteristic of sewage, this paper introduces the design calculation method of the sewage heat exchanger ( evaporation in winter and condensation in summer), proposes an optimized design of arrangement of heat exchange tubes, works out the corresponding design program, and gives the design points and essential parameters of sewage heat exchanger based on the actual case. The results show that the sewage side of heat exchange tubes is smooth without any strengthening methods and that improving the sewage velocity not only increases the heat convection coefficient but also restrains the stable value of the fouling thermal resistance. Increasing the sewage flow path can increase the velocity and improve the heat exchange condition, and the optimal flow path number in the sewage evaporator and condenser is 4 and the arrangement row of tubes includes two modes: side-to-side mode and bottom-to-top mode.rnTo improve the total performance of the sewage heat exchanger, the key problems are how tornstrengthen the coefficient of heat transfer and reduce the fouling thermal resistance in tubes for sewagernside.%在直接式污水源热泵系统中,污水满液式蒸发器和冷凝器的正确合理的设计是系统安全高效运行的关键.文章基于污水的流动阻力与换热特性,阐述了直接式污水源热泵系统中的污水换热器(冬季蒸发、夏季冷凝)的设计方法,以及管排的优化布置方式,编制了相应的设计程序,并结合实际算例给出了污水换热器的热工设计和管排布置的要点和设计所需的重要参数.结果表明:换热管污水侧为光管,无强化措施,增大流速不但可以提高对流换热系数,而且可以抑制污垢热阻稳定值;增加污水的流程数可提高流速进而改善换热,污水蒸发器和冷凝器中的污水以4流程为宜,且管排布置方式可分为水平布置和上下布置两种;提高污水换热器的整体性能,关键在于如何强化污水侧换热系数和减小管内污垢热阻.
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