When a dual-loop coupled refrigerator operates in a coupled state

the condensation pressure of the freezing loop decreases

such that the refrigerant outlet of the condenser is not completely condensed. Hence

the cooling capacity provided by the freezing loop is used to treat the refrigerant that is not completely condensed. It is therefore difficult for the system to take full advantage of the energy-saving ability of the design. To solve this problem

we propose a dual-loop coupled system with two-stage throttling. By adding a throttling expansion device between the freezing condenser and coupled subcooler

the system can operate stably. In this study

the refrigerant is R600a. Under the conditions of ambient temperature of 25 °C and freezer temperature of ?18 °C

we simulated the operating state of the system using Matlab

which was validated by an experimental device. The research results show that the system can maintain stability in both independent and coupled operations when the system works under the design conditions

and the coefficient of performance (COP) of the coupled operation is approximately 9% higher than that of the independent operation.