THE USE OF HYDROCARBONS PROPANE AND ISOBUTANE IN REFRIGERATION SYSTEMS

The object of this work meets the increasing world-wide concern with the environmental problems caused by the use of hydrochlorofluorocarbons refrigerants in refrigeration systems and the viability to substitute them for natural refrigerants. The results of the theoretical study are presented to characterize the hydrocarbons propane (R290) and isobutane (R600a) to be used in refrigeration systems in substitution for the R22. The performances of these refrigerants in refrigeration cycles are compared by using a standart refrigeration cycle, with evaporation temperatures between -20°C to 10°C and condenser temperature of 40°C. This study was carried out with the aid of the Cycle_D simulation program. The refrigerants thermodynamic properties were obtained from REFPROP (NIST). The results showed that both R290 and R600a can be R22 substitutes in this range of application. The hydrocarbon R600a presented a better thermodynamics behavior than the R22 in the majority of the analyzed performance parameters, mainly for evaporation temperatures higher than -10°C. The hydrocarbon R290, showed similar results to the R134a.