Comparative Experimental Investigation of R600a and R600a–R290 Blend Refrigerants in a Vapor Compression Refrigeration Cycle

Due to global concerns regarding climate change and ozone depletion, identifying refrigerants with lower Global Warming Potential (GWP) has become essential. Hydrocarbon refrigerants such as R600a and R290 are gaining attention because of their superior thermodynamic properties and significantly lower GWP compared to conventional refrigerants like R134a and R22. However, while extensive studies exist on R600a and R290 individually, comparatively limited research is available on their blends. Specifically, there is a lack of research on their blended performance at typical ambient conditions, particularly at varying charge levels, such as 50:50 ratios, and on their performance across different charge levels. System performance parameters, compressor suction and discharge characteristics, refrigerating effect, compressor power, and coefficient of performance (COP) were measured at four refrigerant charges: 45, 55, 65, and 75 g. Preliminary analysis reveals that the reduction in COP for R600a/R290 was found to be lower than that for the pure fluids. It can be observed that the COP of a proposed R600a/R290 combination is reduced by about 1.692% at 45 g compared to pure R600a. Whereas, the COP at mass charges of 55 g, 65 g, and 75 g found improvements of about 1.52%, 4.624%, and 8.755%, respectively, for the R290/R600a blend compared to the pure fluids. For both refrigerants, the lowest charge of 45 g yielded the highest COP, indicating that exceeding this optimum charge reduces system efficiency. This study provides meaningful insights into suitable charge selection and performance behavior of hydrocarbon refrigerants for small‐scale refrigeration applications.