Experimental Investigation of a Miniature Refrigeration System Using R134a and a Low GWP Blend R515B

Miniature vapor compression refrigeration systems are gaining increasing relevance in cutting-edge applications such as drone docking station cooling, electric vehicle battery thermal management, portable medical and diagnostic devices, compact beverage dispensers, field-mounted telecom cabinet cooling, as well as the already established fields of electronics and personal cooling. These systems offer a promising pathway to localized and mobile cooling solutions. When coupled with the implementation of alternative low-GWP refrigerants that match or even enhance system performance, the result is a more efficient, environmentally responsible, and potentially sustainable refrigeration technology. Therefore, this study experimentally evaluates the performance of R515B as a low-GWP drop-in replacement for R134a in a miniature vapor compression refrigeration system. Key parameters were analyzed to determine the most suitable operating conditions, resulting in a capillary length of 1.25 m, refrigerant charge of 110 g, compressor speed of 4500 rpm, and high condenser fan speed, under which R515B achieved a COP of 5.16 and a cooling capacity of 252.20 W, representing improvements of 38% and 6.5%, respectively, compared to R134a. These results confirm the viability of R515B as an efficient, environmentally friendly alternative for miniature small-scale vapor compression systems.