Performance optimization of dual-loop cycles using R-600a and hydrocarbon mixtures designed for a domestic refrigerator-freezer

A dual-loop cycle for a domestic refrigerator-freezer (RF) has a large energy saving potential because it has a lower compression ratio due to a higher evaporating temperature in the fresh food compartment (R)-operation compared to a conventional refrigeration cycle, as well as individual optimization flexibility for each loop. In this study, optimizations of dual-loop cycles using R-600a and hydrocarbon (HC) mixtures were individually carried out. Each optimization process included both a theoretical analysis and an experimental investigation. The theoretical analysis was conducted to optimize the specifications of cycle components and the HC mixture compositions for each loop. Based on the experimental results, the energy consumptions of the optimized dual-loop cycles using R-600a and HC mixtures were decreased by 14.2% and 18.6%, respectively, compared with that of a bypass two-circuit cycle using R-600a in the same RF platform.

► Dual-loop cycle optimization with respect to related design parameters.
► Theoretical design for cycle components was conducted.
► Thermodynamic analysis to select the optimum hydrocarbon mixtures was performed.
► The cycle performance was measured and analyzed by varying cycle specifications.
► An 18.6% of energy saving was achieved.