Performance comparison of DME and R134a refrigerants in a room air conditioner: Effect of subcool and superheat

Abstract

The demand for environmentally friendly refrigerants arises to anticipate two global environmental issues: global warming and climate change. The use of environmentally friendly refrigerants is one of the efforts to address these issues. This study aims to investigate the possibility of the use of dimethyl ether (DME) for substituting R134a that has been widely used worldwide. The simulation reveals that both subcool and superheat affect the performance of both refrigerants. The cooling capacity of R134a system increases with the increase of subcool and superheat. Meanwhile, even though the cooling capacity of DME increases with the increase of subcool, it decreases with the increase of superheat. For subcool 0C, DME has a coefficient of performance (COP) 4.8% higher than that of R134a although the cooling capacity is 4.5% lower. When the subcool is set at 8C, the cooling capacity of DME is 6.5% lower than R134a but the COP is 2.6% higher. Another important finding in this study is that the best performance of DME over R134a is obtained at low subcool and low superheat.