Theoretical And Experimental Study Of A High Temperature Heat Pump Refrigerant BY-4

China is a big energy consuming country, in the energy structure map of China, the combustion of fossil fuels is the main way to produce high quality heat energy, it is widely used in various fields of industrial production, high quality energy used in various process will produce low temperature heat(30 ? to 85 ?), the low temperature heat is directly released into the atmosphere, it intensifies the greenhouse gas effect thermal pollution and other environmental hazards. Therefore, developing a method that can use the low temperature heat effectively is very important. High temperature heat pump is one of the effective ways to recycle low temperature heat, it uses less the high potential energy, transform low temperature heat into high temperature energy through consuming less high quality energy, the high grade heat can be used for heating or processing, which can not only improve the efficiency of energy use, but also can reduce the burning of fossil fuels.This paper put forward a environment friendly high temperature non azeotropic refrigerant BY-4, which was developed independently by Tianjin University, the article gave the deal cycle Lorenz cycle and actual vapour compression cycle of BY-4, at the same time, BY-4 and other four kinds of pure refrigerants were compared through theoretical cycle calculation, it can be concluded that the coefficient of performance(COP)?heating capacity unit volume?condensing pressure of BY-4 is more excellent, its thermal physical properties were also better.Based on the thermal physical properties of BY-4, a high temperature heat pump was designed by using BY-4 as working fluid and its heat production was 600 kW. The superheat controller of the electronic expansion valve system was also improved by our research group, so that a certain type of superheat controller on the market can conduct the BY-4 superheat calculation, then the experimental verification was carried to prove the improvement of controller is successful. In order to verify the high temperature performance of BY-4, a test was conducted on a transformed heat pump testing system while the evaporator inlet temperature ranged 40 ? ~ 60 ? and the outlet water temperature of condenser ranged 70 to 110 ??According to the experimental data, the variation of COP, heat capacity, exhaust pressure, exhaust temperature and compressor power with condensing temperature and evaporating temperature was analyzed. The outlet water temperature of condenser can reach 110?, the discharge temperature and condensing pressure is moderate under this condition, when temperature difference between condenser outlet water temperature and evaporator inlet temperature is less than 35 ?, COP is always higher than 3.5.