Energy and Exergy Analysis of a Vapour Compression Refrigeration System Using Zeotropic Refrigerants

Abstract
This study conducts a comprehensive energy and exergy analysis of a Vapor Compression Refrigeration System (VCRS) utilizing four zeotropic refrigerants: R-455A, R-463A, R-290, and R-600a. The performance metrics evaluated include cooling capacity, compressor work, coefficient of performance (COP), exergy destruction, second-law efficiency (ηII), and efficiency defect (ε). The analysis reveals that R-290 and R-600a exhibit the highest cooling capacities of 3.5 kW, highlighting their superior heat absorption capabilities but also indicating a higher energy requirement for the compressor. R-455A, on the other hand, demonstrates the lowest cooling capacity but also the lowest compressor work, suggesting higher energy efficiency. R-463A provides a balanced performance with moderate values for both cooling capacity and compressor work. The COP analysis identifies R-455A as the most efficient refrigerant with a COP of 6.67, followed by R-463A with a COP of 6.00. Exergy analysis shows minimal exergy destruction for R-463A, indicating high efficiency and low irreversibilities, while R-455A presents an anomalous negative exergy destruction value, warranting further investigation. The study concludes that while R-455A and R-463A demonstrate superior second-law efficiencies and moderate efficiency defects, R-290 and R-600a offer significant environmental benefits despite higher exergy destruction and lower second-law efficiencies. Recommendations include further thermodynamic analysis of R-455A, development of advanced VCRS technologies, environmental impact assessments of R-290 and R-600a, and strategies to enhance the energy efficiency of systems using these refrigerants.