Experimental Performance of Prototype Carbon Dioxide Compressors

ABSTRACT This paper describes performance measurements of prototype carbon dioxide compressors using a compressor load stand based on a hot-gas bypass design. Five compressors were tested: a semi-hermetic reciprocating single-stage compressor (Type A) with an estimated cooling capacity of 8.3 kW, a hermetic rotary two-stage compressor (Type B) with an estimated cooling capacity of 2.4 kW, a semi-hermetic reciprocating two-stage compressor (Type C) with an estimated cooling capacity of 10.5 kW, a semi-hermetic reciprocating single-stage compressor (Type D) with an estimated cooling capacity of 0.8 kW, and a semi-hermetic reciprocating single-stage compressor (Type E) with an estimated cooling capacity of 1.6 kW. Compressor tests were conducted for varying suction pressures, superheats and discharge pressures. For each test, refrigerant mass flow rate, power consumption, suction and discharge temperature and pressure were recorded. In addition, the volumetric and overall isentropic efficiencies were calculated. In the end the performance data of all compressors were compared. Volumetric efficiencies range from 0.48 up to 0.90 and the overall isentropic efficien-cies range from 0.40 up to 0.71 for pressure ratios between 1.75 and 6.75.