Two-phase injected and vapor-injected compression: Experimental results and mapping correlation for a R-407C scroll compressor

Vapor compression systems in hot climates tend to operate at higher pressure ratios, leading to increased discharge temperatures, higher irreversibilities during compression, lower specific enthalpies differences across the evaporator, and possibly a reduction in the compressor life due to the breakdown of the oil. To counter these effects, the use of economized, vapor injection compressors is proposed for vapor compression systems in high temperature climates. Such compressors are commercially available however an accurate method for mapping single-port injection compressors is unclear. This paper establishes compressor maps for a single-speed R-407C scroll compressor with two-phase injection and vapor-injected compression. A dimensionless-PI correlation for mapping the injection ratio, refrigerant discharge temperature, compressor power consumption, overall isentropic and volumetric efficiencies, and the heat loss ratio for these compressor maps and a variable speed R-410A compressor with vapor injection is presented. The mapping results are compared to the AHRI 10-coefficient polynomial and another proposed correlation.