PERFORMANCE OF HEAT PUMPS CHARGED WITH R170/290 MIXTURE

摘要

In this study, thermodynamic performance of R170/290 mixture is measured on a heat pump bench tester in an attempt to substitute R22. The bench- tester is equipped with a commercial hermetic rotary compressor providing a nominal capacity of 3.5 kW. All tests are conducted under the summer cooling and winter heating conditions of 7/45 t and -7/41 °C in the evaporator and condenser, respectively.During the tests, the composition of R170 is varied from 0 to 10%with an interval of 2% for R170/290 mixture. Test results show that the coefficient of performance (COP) and capacity of R290 are up to 15.4% higher and 7.5% lower than those of R22 for two conditions, respectively. For R170/290 mixture, the COP decreases and the capacity increases with an increase in the amount of R170. The mixture of R170/290 (4/96) shows a similar capacity and COP as those of R22. For the mixture, the compressor discharge temperature is 17-28°C lower than that of R22. For R170/290 mixture, there is no problem with mineral oil since the mixture is composed of hydrocarbons. The amount of charge is reduced up to 58% as compared to R22. Overall, R170/290 mixture is a good long term 'drop-in' candidate to replace R22 in residential air-conditioners and heat pumps.