Ternary zeotropic mixture with CO2 component for R-22 heat pump application

The paper presents results of a simulation and laboratory study of the performance of a zeotropic mixture R-744/32/134a in a water-heating heat pump. The goal of the research was to obtain operating parameters comparable to a system charged with R-22. The performance of R-22 served as a reference for the ternary mixture studied. A semi-theoretical simulation model was used first to examine the influence of R-744 properties on the mixture performance and to determine the optimum mixture composition. The formulated mixture, R-744/32/134a (7/31/62) was then tested in a laboratory. The experimental apparatus consisted of a counter-flow condenser and evaporator. The primary measurement of capacity was performed on the heat-transfer fluid side. Compressor power was obtained form speed and torque measurements on the open compressors shaft. Compared with the performance of R-22, the COP of R-744/32/134a was better by 9.5% at a 21% increase in volumetric capacity.