3283 -- Test Results a Supercharged Compressor for Commercial Refrigeration PDF

This paper reports on a project whose objective was to quantify the technical benefits of using refrigerant R-502 in a supercharged reciprocating compressor for commercial refrigeration applications. The supercharged compressor concept uses a special heat exchanger that subcools the major portion of the liquid refrigerant leaving the condenser. This subcooling is achieved by flashing the remaining portion of the condensed liquid through an expansion valve, thereby cooling it, and using it to absorb heat from the rest of the refrigerant. This supercharged stream is then fed to the cylinders through ports in the cylinder walls that are uncovered when the piston reaches bottom dead center.

In a previous project, the benefits of the cycle were explored using R-22 at temperatures above O°F, appropriate for heat-pump applications. This project extends the evaporating temperature range downward to -30°F and uses R-502, conditions appropriate for commercial refrigeration.

At 90°F condensing ternperature and -30°F evaporating temperature, capacity was 50% greater than in an otherwise identical, nonsupercharged compressor, and the coefficient of performance (COP) showed a 20% improvement.