An experimental investigation of ejector employed a dual-evaporator vapor compression refrigeration system under various entrainment ratios using R134a as the refrigerant

Abstract

Today, vapor compression refrigeration (VCR) systems are commonly used for cooling and heating in buildings, industrial and many other applications. Given the high-energy costs, it is essential to use highly efficient VCR systems. This study presents an experimental performance analysis of a refrigeration cycle with a dual evaporator ejector system (DEES). For this aim, an experimental system was designed and established on a laboratory scale. DEES system was organized for regarding different and possible applications via operating the individual evaporators with different heat sources as air and water. Within the scope of the work performed in this study, the DEES was tested by varying the condensing temperature and ejector Entrainment Ratio (ER) values. The investigated DEES was also contrasted with a conventional vapor compression refrigeration cycle as a baseline system considering different operating conditions. The findings obtained in this study showed that a 13.24% enhancement in coefficient of performance (COP) was achieved when comparing with the baseline system. The highest exergy destruction rate for the compressor in ER#3 was 0.79 kW, but the total cooling capacity significantly improved compared to the baseline system. Additionally, the total exergy destruction rate of the baseline system was the lowest compared to the other modes, while the cooling capacity of this mode was always the lowest. It was also found that when the ER value varied from ER#3 to ER#1, the total cooling capacity increased by up to 11.79%. The results show that the ejector works more efficiently at low ER values and condenser temperatures.