Abstract: According to one embodiment, a cascade refrigeration cycle apparatus according to the present embodiment includes a high-temperature-side and a low-temperature-side refrigeration circuits, an inverter and a control section. The high-temperature-side refrigeration circuit includes a first compressor and a cascade heat exchanger. The low-temperature-side refrigeration circuit includes a second compressor and the cascade heat exchanger. The inverter connected to at least one of the compressors. The control section controls the inverter so that a set operating frequency for the first compressor is higher than a set operating frequency for the second compressor when an operation of the apparatus is started.

Abstract: According to one embodiment, an apparatus includes a housing, two high-temperature-side refrigeration circuits and two low-temperature-side refrigeration circuits. Each of the high-temperature-side refrigeration circuits is configured to exchange heat with both of the two low-temperature-side refrigeration circuits by cascade heat exchangers. A hot-water pipe letting water or hot water through water-refrigerant heat exchangers of the high-temperature-side refrigeration circuits is provided. When the low-temperature-side refrigeration circuit conducts a defrosting operation of the evaporator, the low-temperature-side refrigeration circuits are controlled in such a way that the low-temperature-side refrigerant circuit releases heat in the cascade heat exchanger.

Abstract: According to one embodiment, an apparatus includes a housing, two high-temperature-side refrigeration circuits and two low-temperature-side refrigeration circuits. Each of the high-temperature-side refrigeration circuits is configured to exchange heat with both of the two low-temperature-side refrigeration circuits by cascade heat exchangers. A hot-water pipe letting water or hot water through water-refrigerant heat exchangers of the high-temperature-side refrigeration circuits is provided. When the low-temperature-side refrigeration circuit conducts a defrosting operation of the evaporator, the low-temperature-side refrigeration circuits are controlled in such a way that the low-temperature-side refrigerant circuit releases heat in the cascade heat exchanger.

Abstract: According to one embodiment, a cascade refrigeration cycle apparatus according to the present embodiment includes a high-temperature-side and a low-temperature-side refrigeration circuits, an inverter and a control section. The high-temperature-side refrigeration circuit includes a first compressor and a cascade heat exchanger. The low-temperature-side refrigeration circuit includes a second compressor and the cascade heat exchanger. The inverter connected to at least one of the compressors. The control section controls the inverter so that a set operating frequency for the first compressor is higher than a set operating frequency for the second compressor when an operation of the apparatus is started.