자동차용 대체냉매 직접팽창 시스템 성능 평가를 위한 실험적 연구

The aim of this study is to investigate the performance of air conditioning system for alternative refrigerants with the direct expansion system. Due to environmental regulation as a global issue, R-134a, present mobile A/C refrigerant, need to be substituted before long. Among possible alternative refrigerants, R-1234yf has been highly regarded in Mobile Air Conditioning System(MACS) because of similar operating pressure characteristic and technologies to apply have been studied. In this study, R-1234yf and R-744, which have direct expansion system like the present refrigerant, were analyzed on the performance, such as cooling capacity and coefficient of performance(COP), compared to R-134a. As the results of various experiments which were fulfilled like real operating conditions on the road, averaged cooling capacity of R-1234yf was about 96.0 % while that of R-744 was about 97.0 % compared to R-134a and in case of averaged COP, R-1234yf was about 92.0 % while R-744 was about 70 % . From this, R-1234yf and R-744 need additional technical developments to cope with insufficient performance, such as internal heat exchanger re-design and expansion valve"s set-up value. Further studies of improved alternative refrigerant A/C system with the direct expansion will be required to change a refrigerant for MACS.