Study On Application Of Plastic Heat Exchanger In Sewage Source Heat Pump

The heat pump retrieves low quality heat through consuming a small amount of high quality energy in order to meet the need of production and life. The city untreated sewage is an excellent renewable low potential energy because it is moderate temperature, large quantity and widespread distribution. Sewage source heat pump systems are environmental friendly, high efficiency and energy saving. And the particularity of sewage quality makes it difficult to expand this system while gathering thermal energy, choosing heat exchangers and considering the corrosion and fouling. Based on the problems of existing exchangers, combining with the sewage specialties, this paper puts forward the plastic heat exchangers to replace metal ones for solving heat exchangers corrosion and fouling.Based on detailed analyzing the application and development of plastic heat exchangers at home and abroad, one approach was advanced that by substituting plastic heat exchanger made of thin wall and canaliculus PTFE plastic tube for the metal heat exchanger of traditional metal heat exchanger. Experiments are made to study flow characteristics and fouling trend of untreated sewage. And the PTFE heat exchanger is designed. The performance of the PTFE heat exchanger is studied through the numerical simulation method. The heat transfer coefficient is obtained on several diameters and conditions of velocity. This paper is studed on comparison between metal heat exchangers and the plastic heat exchanger.The constitutive equation of sewage viscous is presented. The results of the theology experiment indicate that the sewage is a yield pseudo plastic fluid. The fouling growth characteristics of some kinds of material have been experimentally. The results indicate that the plastic pipe is low scaling. The heat transfer coefficient of PTFE heat exchanger can achieve 360W/(m 2? K), and the change of the heat transfer coefficient is obtain with several diameters. According to the characteristics of corrosion, fouling, heat transfer, the plastics heat exchanger has advantages in volume, installation cost, stability. The research of this paper can expand the design thought of heat exchanger of the sewage source heat pump and application area of plastic heat exchanger and it has some academic value and social value.