Experimental Study On The Effect Of Little R744 On The Performance Of R290 Air Source Heat Pump Water Heater

With the improvement of the ozone hole,global warming has been increasing year by year,is still facing a tough battle in the field of promoting the reduction of greenhouse gas emissions.The international community has begun to take measures to limit the use of high global warming potential of HFCs synthetic refrigerants,zero ODP,low GWP natural refrigerants are re favored.R744(CO2)belongs to the low temperature and high pressure refrigerant,but the strength of materials and accessories,sealing and other aspects of the more demanding;R290(propane)as alternative refrigerants the ideal in hydrocarbons,compared with R22,the latent heat of vaporization has low vapor pressure and high explosive,but it is the biggest security risk.Based on the advantages and disadvantages of each other,the R744/R290 mixture is composed of a certain mass ratio,and a large number of studies have been done on the circulation characteristics of the air source heat pump water heater.First of all,the R22 refrigerant is tested.The test results show that the R22 filling volume in 1.15 kg,coefficient of performance(COP)the system to a maximum of 4.176;secondly,the R290 refrigerant were directly pouring test results show that the optimum filling system of R290 irrigation amount is 450 g,the COP is 3.907.In charge of R290 system optimal irrigation amount,set the opening were studied,the results showed that the different expansion valve in pulse opening 300 P,and the COP of R290 system is a maximum of 4.251,increased by 8.8% compared with the direct infusion of alternatives;a little higher than that of R22 system,and the filling quantity is only R22 of 39.1%.According to the test performance of R290 system with different opening degree,the R744/R290 mixture was applied to the air source water heater by changing the filling rate and the expansion valve opening degree.The results show that the optimum charge of R744/R290 mixed refrigerants for irrigation in the vicinity of 525 G,the performance of the heating performance coefficient of the system and R22 system;mixed refrigerant in the optimal filling amount,respectively 250 P,275P,set the opening of 300 P,325P and 350 P were tested,the results show that the best opening is the same for 300 P the heating performance coefficient,the maximum is 4.127,the ratio of direct mixed refrigerant COP increased by 13.2%;recommend the use of mixed refrigerant filling quantity is 525 G,the opening is the combination of 300 P applied to the air source heat pump water heater.This paper provides a useful reference for the further study of the R744/R290 air source heat pump water heater,R744/R290 mixed refrigerant has an advantage in environmental performance,and has broad market prospect.