Refrigeration cycle system

A refrigeration cycle system comprising:

• a first circuit allowing circulation of a first refrigerant and including a first compressor, a cascade heat exchanger, a first heat exchanger, and a first switching mechanism configured to switch a flow path of the first refrigerant;
• a second circuit allowing circulation of a second refrigerant and including a second compressor, the cascade heat exchanger, and a second heat exchanger;
• a heating medium supply configured to supply a heating medium to exchange heat with the second refrigerant flowing in the second heat exchanger;
• and
• a controller comprising
• at least one processor, and
• actuators controlled by the at least one processor to regulate operation of the heating medium supply, the first and second compressors, and the first switching mechanism,
• wherein the at least one processor is programmed to control the actuators to perform a process comprising
• executing a first operation of operating the heating medium supply in an active mode while circulating the first refrigerant in the order of the first compressor, the cascade heat exchanger, and the first heat exchanger and circulating the second refrigerant in the order of the second compressor, the second heat exchanger, and the cascade heat exchanger,
• while the first operation is being executed, and in response to a first condition being satisfied during the execution of the first operation, executing a second operation to operate the second compressor while stopping or decreasing the heating medium supply in supply quantity of the heating medium, and
• in response to a second condition being satisfied during the execution of the second operation, execute a third operation of circulating the first refrigerant in the order of the first compressor, the first heat exchanger, and the cascade heat exchanger.