Comparative investigation of vapour compression-triple effect absorption cascade refrigeration system operating with different refrigerants in vapour compression cycle

Abstract In this study, a multi-objective optimization of a vapor compression triple-effect absorption cascade cooling system (VC-TEA-CCS) is explored by maximizing the maximization of COP) and exergy efficiency. First, a theoretical analysis of the cycle was performed, and the vapor-compression cycles of different refrigerants were compared. In the vapor compression cycle, the working fluids were considered as R1234yf, R290, R1234ze, and R123, whereas in the absorption cycle, lithium-bromide-water was selected as the working pair. The selected parameters (six), such as the generator temperature, condenser temperature, evaporator temperature, heat exchanger efficiency, overlap temperature, and cascade heat exchanger temperature, were analyzed for the said system to obtain better performance (i.e., highest COP and exergy efficiency). Additionally, the cycle was optimized by applying surface response methods (RSM) based on a central composite design (CCD). In addition, based on the design of the experiment, regression and ANOVA analyses were conducted, and optimal parameters were identified. The optimum results were attained at Tg = 173.58oC, Tc = 30oC °C, Te = 5.08oC, ΔT = 5.02 oC, and plant size = 3000 kW, and the optimized COP and exergy efficiency were estimated as 2.1 and 91.5%, respectively.