An Experimental On Heat Transfer Characteristics Of The Cascade Heat Exchanger In Refrigeration System Using R32/CO2

An experimental on heat transfer characteristics of the cascade heat exchanger in a refrigeration system was investigated. In this paper, the cascade system used the couple of R32/CO
₂
as refrigerant: CO
₂
in low stage cycle, R32 in high stage cycle. The heat exchanger is double-tube type with arranging the spiral shape, with the inner diameters are 4 mm and 8 mm for the inner tube and the outer tube, respectively. Using a microchannel evaporator, this system was operated with the evaporative temperature of -26°C. In this study, the temperature profile and the thermal capacity were determined. Moreover, the results obtained from the experimental data are good agreement with the theoretical calculations. These results are very important to calculate and design the cascade heat exchanger using CO
₂
.