Study On The Characteristics Of Solar Ejector Refrigeration System With HFO/HFCs Mixed Refrigerant

With the aggravation of energy crisis and environmental pollution,more and more attention has been paid to clean energy such as solar energy,biological energy and wind energy.As a green energy-saving technology,solar refrigeration technology has attracted worldwide attention for its ability to provide efficient space cooling(heat),hot water supply and industrial heating.It is an important way to alleviate the energy crisis and protect the environment that the solar refrigeration system can completely or partly replace the conventional air conditioning system.However,solar energy refrigeration efficiency is relatively low.In order to further improve the efficiency of solar ejector refrigeration system,this subject establishes system simulation program based on EES,and studies the performance of solar ejector refrigeration system with zero ODP and low GWP mixtures.The main work is as follows:First,the refrigerant optimization principle is determined through research literature,and the environmental performance and safety performance of the working fluid are comprehensively considered for screening.By analyzing the environmental performance,safety performance,saturated steam pressure,critical pressure,critical temperature,temperature slip performance,density,thermal conductivity,dynamic viscosity and other properties of the working medium,zero ODP,low GWP working medium R1234 yf and R1234 ze are selected as the basic group.Selecting R134 a,R32,and R152 a as the second component from the alternative second components R134 a,R32,R152 a,R600a,and R290,and finally selecting four groups of R1234yf/R134 a,R1234ze/R134 a,R1234yf/R32,and R1234yf/R152 a.The mixed working fluid was subjected to simulation calculation.Secondly,based on the EES program,the corresponding steady-state mathematical models of the mixed working fluid evaporator,condenser,generator,ejector,throttling mechanism and working fluid pump are established.Based on the calculation models of each component,the simulation model of solar ejector refrigeration system with HFO/HFCs mixed refrigerant is established.Finally,based on the above-mentioned optimized refrigerants and the established simulation model,the changes of COP,EER,ejection coefficient,unit refrigeration capacity,power consumption and condensation pressure of solar ejector refrigeration system under different mixing refrigerants are analyzed.The results show that there are optimal mass ratios of R1234yf/R134 a,R1234ze/R134 a,R1234ze/R32 and R1234ze/R152 a mixtures,which make the COP of the system reach to the maximum,the corresponding mass ratios are 0.5/0.5,0.6/0.4,0.7/0.3 and 0.7/0.3,respectively.The corresponding COP values are 0.192,0.19,0.26 and 0.225,and the EER are 4.115,4.11,4.41 and 4.13,respectively.The largest working medium for COP is R1234ze/R32(0.7/0.3),The COP of R1234ze/R32(0.7/0.3)system increased by 28.46%,29.2%,27.77%,11.53% and 26.53%,respectively,compared with the pure working fluids R1234 yf,R1234ze,R134 a,R32 and R152 a,and increased by 26.15%,26.92%,and 13.46%,respectively,compared with R1234yf/R134a(0.5/0.5),R1234ze/R134a(0.6/0.4)and R1234ze/R152a(0.7/0.3).