Analysis of compression–absorption cascade refrigeration cycles

Abstract

In this study, LiBr–H2O pair was used for the first time for absorption section of compression–absorption cascade refrigeration cycles. These cycles were analyzed theoretically and compared with using different refrigerants in the compression and absorption sections. While LiBr–H2O and NH3–H2O are used as fluid pair in cascade absorption section, R134a, R-410A and NH3 fluids were used in the vapour compression section of cascade cycle. It was presented that electrical energy consumption in the cascade refrigeration cycle is 48–51% lower than classical vapour compression refrigeration cycles that use R134a, R-410A and NH3 as working fluids under the same operating conditions, that are an evaporator temperature of 263 K and a condenser temperature of 313 K. Separately the results show that by using LiBr–H2O pair for absorption section the thermal energy consumption of cascade refrigeration cycle could be reduced by 35% and also general coefficient of performance (COPcyclegen) could be improved by 33% compared to the NH3–H2O pair.