Experimental analysis on two stage scroll compressor using R32 refrigerant with and without vapour injection in heat pump

This research article presents an experimental investigation of a two-stage scroll compressor using R32 refrigerant, focusing on the effects of vapor injection in heat pump applications. The study highlights the performance improvements achieved through vapor injection, with particular emphasis on operation at low ambient temperatures. Key performance indicators—heating capacity, coefficient of performance (COP), and discharge temperature—were selected to evaluate system efficiency. Notably, at an ambient temperature of − 20 °C, the vapor-injected system exhibited a 17.01% increase in COP and a 13.73% reduction in discharge temperature compared to a conventional system without vapor injection. Optimal injection ratios and intermediate pressures were identified as critical parameters for maximizing system performance. Furthermore, the integration of an internal heat exchanger (IHX) demonstrated potential in stabilizing compressor operation and enhancing reliability by limiting the maximum discharge temperature—an essential factor in ensuring safe and effective operation under freezing conditions. The study also observed that vapor injection helps reduce the discharge temperature during prolonged operation, contributing to system longevity. Overall, the findings confirm that vapor injection is a promising strategy for improving the efficiency and performance of heat pumps, particularly in cold climates. This work contributes to a deeper understanding of the operational characteristics of two-stage scroll compressors with vapor injection and provides strong evidence supporting the use of R32 refrigerant in environmentally and energy-efficient heat pump systems.