Investigation of the Efficiency of a Two-Stage Isobutane Heat Pump

The paper substantiates the relevance of studying the methods for improving the efficiency of heat pumps. Two schemes of two-stage heat pumps and models for them are developed, which permitted calculating the thermal characteristics of cycles. The schemes differ by the presence of a supercooler for condensate. Conclusions are made about the advantages of isobutane as a working fluid over other substances. Maps of modes for the calculated coefficient of thermal transformation are constructed. It is shown that two-stage pumps have a higher coefficient of transformation than single-stage ones. The presence of supercoolers increases the transformation coefficient for both single-stage and two-stage heat pumps. It is found that the coefficient of thermal transformation of the second stage increases with an increase in the temperature difference between the freon temperature at the inlet to the second-stage compressor and the condenser temperature of the second stage.