Thermodynamic Evaluation of Novel Ejector-Integrated Compression–Absorption Cascade Refrigeration System

The compression–absorption cascade refrigeration cycle (CACRC) has attracted considerable interest due to its advantages of decreasing electricity consumption and enhancing efficiency of energy utilization. To further reduce irreversibility and improve energy efficiency, the ejector was integrated into an absorption refrigeration subsystem (EA1, EA2) and a vapor-compression refrigeration subsystem (EC1, EC2, EC3) in the CACRC, respectively. Six novel ejector-based CACRC systems (EA1-EC1, EA1-EC2, EA1-EC3, EA2-EC1, EA2-EC2, and EA2-EC3 cascade systems) were developed in this work. A comparative analysis was performed to evaluate the performance of the proposed systems and conventional CACRC using NH3/H2O and R41 as working fluids. The effects of the evaporator temperature, generator temperature, condenser temperature, absorber temperature, and the temperature difference across the cascade heat exchanger on COP, ECOP, input power, and total exergy destruction of the system were analyzed. Results show that the proposed ejector-based CACRC systems have better performance than that of the conventional CACRC. The EA1-EC1 cascade system has the superior performance, and the improvements of COP and ECOP are about 7.96% and 10.86% compared to the conventional CACRC. The analysis of exergy destruction for each component in the proposed system shows that the main exergy destruction occurs in the generator, compressor, and absorber.