Performance Prediction Of Alternative Refrigerant In The Air Conditioning System

Since the CFC and HCFC were found,their commercial production and widely application in refrigerating and air-conditioning industry are special for R22 of excellent performance to bring about the promote of economy and great development of HVAC industry,caused damages which cannot be ignored to sustainable society,the most prominent ones included ozone hole and global warming.At the 19 th meeting of The Montreal Protocol on ozone depleting substances,parties reached an agreement the time of complete obsolete on HCFCs in the developing countries is in advance to 2030.With a view of the harmonious development,accelerating to develop new alternative refrigerants to replace R22 which is widely used at the present is a priority for HVAC.On account of pressing need of the new environmental refrigerants,two kinds of new non-azeotropic mixture refrigerants named A and B with ODP of 0 and low GWP were proposed in this paper,which need theoretical study and experimental analysis carrying on the study of the performance of the cycle of the two refrigerants,finally got detailed data analysis.Physical parameters of refrigerants of A,B and R22、R32 and R410 a indicated A and B have good environmental performance: the ODP are 0.02 and 0,GWP are both 1000,they also have moderate critical temperatures,superior performance,and the potential to further study.In order to ensure the reliability and validity of unit,considering the conditions of bench test: a lack of automatical components and weak in feedback function,so some detailed work was planned to the electronic expansion valve.Expansion valve is one of the four main parts in air conditioning unit,whose significant role is throttling and depressurization and regulating refrigerants,is also the key of the system because its responsibility to guarantee appropriate pressure differential between the condenser and evaporator.A,B and R22 would be in three openness of the expansion valve to determine optimal one because there are problems in matching with units,especially most of them are matching R22,which are not fit for new refrigerants.Three kinds of refrigerants had same working condition: the inlet temperature of low temperature heat was setting at 12 ℃,and the return one was 7 ℃;the inlet temperature of the water high temperature heat was setting at 25 ℃,the return water’s temperature was 30 ℃,the temperature difference were both 5 ℃.Due to the affects of expansion valve opening on test,R22 had openings: 70%,75%,80%;A and B would be set extra openness of 65% and 85%(opening of 85% was got rid of)because of not enough known about them.When the valve opening was 65%,circulation and the degree of the superheat were both suitable,A achieve the optimal state;those of B and R22 were 75% and 80%.Comparing of data of them,B might not do well,but results of A were better: important parameters of refrigerating capacity and COP,2.41% and 2.87% higher than R22,the COP broke 4.0,who has great potential in energy saving;exhaust pressure,less than 10% higher than R22,but compression ratio was 4.2% lower than it;compressor power input of A fell 4.6%,the temperature of high exhaust was 0.2% higher than R22.Results showed A has advantages in environmental performance,refrigerating capacity and COP,it has great potential to replace R22;will provide guide for screening and optimization to refrigerants in the future.