Abstract: A refrigerant circuit includes a first compressor connected to a first suction pipe and a first discharge pipe and configured to compress a refrigerant, a second compressor connected to a second suction pipe and a second discharge pipe and configured to compress the refrigerant discharged from the first compressor, a radiator, and a high-pressure passage connecting the second discharge pipe and the radiator. A first oil drain passage guides an oil in the second compressor to one of the first suction pipe and an intermediate port of the first compressor, without via the high-pressure passage.

Abstract: An icemaking system includes: a refrigerant circuit that executes a vapor compression refrigeration cycle; a circulation circuit that circulates solution as a cooling target of the refrigerant circuit; and a control device that controls refrigerant evaporation temperature at the refrigerant circuit. The circulation circuit includes a solution flow path of: an ice generator; a solution tank that stores the solution; and a pump that pressure feeds the solution to the solution flow path. The refrigerant circuit includes: an evaporator of the ice generator; a compressor; a condenser; and an expansion valve. The control device includes a central processing unit (CPU) that adjusts to lower evaporation temperature at the evaporator as the solution has higher solute concentration.

Abstract: An ice making system includes: a refrigerant circuit that performs a vapor compression refrigeration cycle and that includes a compressor, a condenser that condenses refrigerant discharged from the compressor, a first expansion valve with an adjustable opening degree that decompresses the refrigerant from the condenser, a flooded evaporator that evaporates the refrigerant decompressed by the first expansion valve, and a superheater that imparts a degree of superheating to the refrigerant discharged from the flooded evaporator; a circulation circuit that circulates a medium that is cooled by the flooded evaporator; and a control device that controls the adjustable opening degree of the first expansion valve such that the superheater imparts to the refrigerant discharged from the flooded evaporator a degree of superheating at which dryness of the refrigerant is kept within a predetermined range of less than 1.

Abstract: An icemaking system includes a circulation circuit configured to circulate icemaking solution, at least one icemaker provided in the circulation circuit, a cooling mechanism, a first detector and an adjuster. The icemaker includes a cooling chamber and a scraping mechanism. The cooling chamber has an inflow port and an exhaust port of solution, and the cooling chamber allows the solution to flow in the cooling chamber. The scraping mechanism scrapes ice generated on an inner surface of the cooling chamber. The cooling mechanism cools the solution in the cooling chamber. The first detector detects whether the inflow port of the cooling chamber has an ice nucleus. The adjuster adjusts a cooling temperature of the solution in accordance with a detection result of the first detector.

Abstract: Provided is a refrigeration apparatus capable of reducing the leakage of a refrigerant even when a refrigerant leak occurs in a defrosting operation of a usage-side heat exchanger. When a refrigerant leak situation around a usage-side heat exchanger satisfies a predetermined leak condition in performing a defrosting operation with a connection state of a four-way switching valve brought into a defrosting connection state in which a heat source-side heat exchanger functions as an evaporator for a refrigerant and a usage-side heat exchanger functions as a radiator for the refrigerant, a controller performs density lowering control to lower a refrigerant density in the usage-side heat exchanger while maintaining the four-way switching valve at the defrosting connection state.

Abstract: An icemaking system includes a circulation circuit configured to circulate icemaking solution, at least one icemaker provided in the circulation circuit, a cooling mechanism, a first detector and an adjuster. The icemaker includes a cooling chamber and a scraping mechanism. The cooling chamber has an inflow port and an exhaust port of solution, and the cooling chamber allows the solution to flow in the cooling chamber. The scraping mechanism scrapes ice generated on an inner surface of the cooling chamber. The cooling mechanism cools the solution in the cooling chamber. The first detector detects whether the inflow port of the cooling chamber has an ice nucleus. The adjuster adjusts a cooling temperature of the solution in accordance with a detection result of the first detector.

Abstract: an ice making system includes a tank that stores a medium to be cooled, an ice making machine that cools the medium and makes ice, a pump that circulates the medium between the tank and the ice making machine, a de-icing mechanism that heats the medium and melts the ice in the ice making machine, and a control device that controls operations of the ice making machine, the pump, and the de-icing mechanism. The ice making machine includes a cooling chamber that cools the medium, an inflow port through which the medium flows into the cooling chamber, and a discharge port through which the medium is discharged from the cooling chamber. The control device activates the de-icing mechanism when a pressure difference between a pressure of the medium at the inflow port and a pressure of the medium at the discharge port exceeds a predetermined value.

Abstract: Provided is a refrigeration apparatus capable of, even in occurrence of a refrigerant leak, suppressing the extent of the refrigerant leak in continuously operating a usage unit other than a usage unit at which the refrigerant leak occurs.

Abstract: A refrigeration system includes a plurality of utilization units provided for one air conditioning target space, a refrigerant leakage sensor that detects a leakage of the refrigerant in a lower part of the air conditioning target space, and a control unit. In a case where the refrigerant leakage sensor detects the refrigerant leakage, the control unit performs detection standby control on the utilization units such that the supply of the refrigerant to utilization-side heat exchangers is temporarily stopped. In a case where the refrigerant leakage is detected based on the state quantity of the refrigerant corresponding to the utilization units under the detection standby control, the control unit stops the use of the utilization unit in which the refrigerant leakage has been detected.

Abstract: An ice making system includes: a tank that stores a medium to be cooled; an ice making machine that cools the medium and makes ice; a pump that circulates the medium between the tank and the ice making machine; a de-icing mechanism that performs a de-icing operation of heating and melting the medium in the ice making machine; and a control device that controls operations of the ice making machine, the pump, and the de-icing mechanism. The ice making machine includes: a cooling chamber in which the medium is cooled; a blade mechanism that rotates in the cooling chamber and disperses the ice; a detector that detects a locked state of the blade mechanism; and a first temperature sensor that is disposed at a discharge port of the cooling chamber and detects a temperature of the medium discharged from the cooling chamber.

Abstract: An ice making system includes: a tank that stores a medium to be cooled; an ice making machine that cools the medium and makes ice; a pump that circulates the medium between the tank and the ice making machine; a de-icing mechanism that performs a de-icing operation of heating and melting the medium in the ice making machine; and a control device that controls operations of the ice making machine, the pump, and the de-icing mechanism. The ice making machine includes: a cooling chamber in which the medium is cooled; a blade mechanism that rotates in the cooling chamber and disperses the ice; a detector that detects a locked state of the blade mechanism; and a first temperature sensor that is disposed at a discharge port of the cooling chamber and detects a temperature of the medium discharged from the cooling chamber.

Abstract: An ice making system includes a tank that stores a medium to be cooled, an ice making machine that cools the medium and makes ice, a pump that circulates the medium between the tank and the ice making machine, a de-icing mechanism that heats the medium and melts the ice in the ice making machine, and a control device that controls operations of the ice making machine, the pump, and the de-icing mechanism. The ice making machine includes a cooling chamber that cools the medium, an inflow port through which the medium flows into the cooling chamber, and a discharge port through which the medium is discharged from the cooling chamber. The control device activates the de-icing mechanism when a pressure difference between a pressure of the medium at the inflow port and a pressure of the medium at the discharge port exceeds a predetermined value.

Abstract: An icemaking system includes: a refrigerant circuit that executes a vapor compression refrigeration cycle; a circulation circuit that circulates solution as a cooling target of the refrigerant circuit; and a control device that controls refrigerant evaporation temperature at the refrigerant circuit. The circulation circuit includes a solution flow path of: an ice generator; a solution tank that stores the solution; and a pump that pressure feeds the solution to the solution flow path. The refrigerant circuit includes: an evaporator of the ice generator; a compressor; a condenser; and an expansion valve. The control device includes a central processing unit (CPU) that adjusts to lower evaporation temperature at the evaporator as the solution has higher solute concentration.

Abstract: An ice making system includes: a refrigerant circuit that performs a vapor compression refrigeration cycle and that includes a compressor, a condenser that condenses refrigerant discharged from the compressor, a first expansion valve with an adjustable opening degree that decompresses the refrigerant from the condenser, a flooded evaporator that evaporates the refrigerant decompressed by the first expansion valve, and a superheater that imparts a degree of superheating to the refrigerant discharged from the flooded evaporator; a circulation circuit that circulates a medium that is cooled by the flooded evaporator; and a control device that controls the adjustable opening degree of the first expansion valve such that the superheater imparts to the refrigerant discharged from the flooded evaporator a degree of superheating at which dryness of the refrigerant is kept within a predetermined range of less than 1.

Abstract: A refrigeration apparatus includes: a usage-side expansion valve whose opening degree is changed in response to a change in a flow rate or a pressure of a refrigerant on the upstream side; a first expansion valve; and a controller. The controller exerts, in an oil recovery operation, an oil recovery first control on the first expansion valve to attain a first opening degree (an opening degree of increasing an opening degree of the usage-side expansion valve in relation to a reduction in the flow rate or the pressure of the refrigerant passing through the first expansion valve), to reduce the flow rate or the pressure of the refrigerant passing through the first expansion valve.

Abstract: A refrigeration apparatus implements a control method capable of suppressing occurrence of a situation in which a refrigerating machine oil from an oil separator is unsatisfactorily returned to a compressor and a discharge gas refrigerant is mostly returned to the compressor. An oil return valve is disposed on an oil return pipe connecting an oil separator disposed on a discharge side of a compressor to an injection pipe for supplying a refrigerant to the compressor. A controller controls the oil return valve to reduce a flow rate when a temperature of the refrigerant discharged from the compressor or a pressure of the refrigerant flowing through the injection pipe satisfies a predetermined condition.

Abstract: A refrigeration system includes a plurality of utilization units provided for one air conditioning target space, a refrigerant leakage sensor that detects a leakage of the refrigerant in a lower part of the air conditioning target space, and a control unit. In a case where the refrigerant leakage sensor detects the refrigerant leakage, the control unit performs detection standby control on the utilization units such that the supply of the refrigerant to utilization-side heat exchangers is temporarily stopped. In a case where the refrigerant leakage is detected based on the state quantity of the refrigerant corresponding to the utilization units under the detection standby control, the control unit stops the use of the utilization unit in which the refrigerant leakage has been detected.

Abstract: Provided is a refrigeration apparatus capable of, even in occurrence of a refrigerant leak, suppressing the extent of the refrigerant leak in continuously operating a usage unit other than a usage unit at which the refrigerant leak occurs.

Abstract: Provided is a refrigeration apparatus capable of reducing the leakage of a refrigerant even when a refrigerant leak occurs in a defrosting operation of a usage-side heat exchanger. When a refrigerant leak situation around a usage-side heat exchanger satisfies a predetermined leak condition in performing a defrosting operation with a connection state of a four-way switching valve brought into a defrosting connection state in which a heat source-side heat exchanger functions as an evaporator for a refrigerant and a usage-side heat exchanger functions as a radiator for the refrigerant, a controller performs density lowering control to lower a refrigerant density in the usage-side heat exchanger while maintaining the four-way switching valve at the defrosting connection state.

Abstract: A refrigerating apparatus having a plurality of compressors includes an injection circuit (40) which includes a first injection pipe (37) branched from a first refrigerant pipe (32) of a refrigerant circuit (10) and branch injection pipes (37a, 37b, 37c) branched from the first injection pipe (37), a subcooling pressure-reducing valve (29) provided to the first injection pipe (37), and flow rate adjusting valves (30a, 30b, 30c) provided to the branch injection pipes (37a, 37b, 37c), respectively, thereby providing an appropriate refrigerant injection to each of the compressors.