The paper describes an experimental determination of the mass flow of refrigerant per minute and refrigerating effect per minute in a vapour-compression refrigerator, when the state of the refrigerant at the exit from the evaporator was varied over a wide range of superheat temperatures and dryness fractions. The usual methods of measuring the flow of liquids in pipes were not suitable for the present work and a special type of flow meter, described in the text, was developed. The results obtained were not as theory would tend to suggest, but were substantially modified by practical conditions, particularly for dryness fractions between 0·97 and 0·87. The volumetric efficiency changed abruptly over this range from a higher to a lower value. The reduction was attributed to the effect of re-evaporation of. the liquid portion of the refrigerant in the compressor during the suction stroke, as it was found that the higher volumetric efficiency was obtained when the refrigerant was superheated throughout most of the delivery stroke, and the lower volumetric efficiency occurred when the state of the refrigerant on entering the compressor resulted in liquid being present in the cylinder at the end of the delivery stroke. The reduction in the volumetric efficiency resulted in a corresponding reduction in the mass flow, the refrigerating effect, and the heat rejected by the condenser per minute, and in the coefficient of performance for dryness fractions ranging between 0·97 and 0·87.
Analysis of energy efficiency of air handling unit with integrated air to air heat exchanger in heating mode