Abstract: A refrigeration apparatus includes a gas-liquid separator on a downstream side of a radiator, and a refrigerant circuit in which a high pressure of a refrigeration cycle is equal to or higher than a critical pressure. The refrigeration apparatus includes a gas passage that communicates with the gas-liquid separator and at least one of a plurality of heat exchangers provided in the refrigerant circuit, and an opening and closing device that opens and closes the gas passage. There is provided a controller that opens the opening and closing device when a pressure in the gas-liquid separator is equal to or higher than a predetermined value in a state where a compression unit of the refrigerant circuit is stopped to suppress occurrence of pressure abnormality inside the gas-liquid separator in a state where a compressor is stopped.

Abstract: A refrigeration apparatus includes a heat source-side unit and a utilization-side unit that are connected to each other, and performs a refrigeration cycle in which a high pressure of a refrigerant reaches or exceeds a critical pressure. The refrigeration apparatus also includes a control unit configured to perform a first action of returning the refrigerant to the heat source-side unit when a stop condition of the utilization-side unit is satisfied, and a second action of prohibiting the first action when a pressure at the heat source-side unit is equal to or more than the critical pressure of the refrigerant. This configuration suppresses damage to a refrigerant storage reservoir and the like in returning the refrigerant to the heat source-side unit.

Abstract: A heat source-side unit (10) includes a heat source-side circuit (11). The heat source-side circuit (11) includes a compression unit (20) including a lower-stage compression element (23) and a higher-stage compression element (21), an intermediate heat exchanger (17) disposed on a refrigerant path between the lower-stage compression element (23) and the higher-stage compression element (21), and a bypass passage (23c) connected to a suction pipe (23a) and a discharge pipe (23b) each connected to the lower-stage compression element (23). At startup of the compression unit (20), a first action is performed for stopping the lower-stage compression element (23) and operating the higher-stage compression element (21). This configuration thus suppresses occurrence of liquid compression at startup of a compressor.

Abstract: A heat source unit constitutes a refrigeration apparatus by being connected to a utilization-side unit. The heat source unit includes a low-stage compression element, a high-stage compression element, and a heat exchanger. The low-stage compression element has a discharge pipe provided with a pressure switchgear. The high-stage compression element compresses a refrigerant discharged from the low-stage compression element. When the low-stage compression element is paused in response to activation of the pressure switchgear, the high-stage compression element operates while the low-stage compression element is kept paused.

Abstract: A refrigerant circuit of a refrigeration apparatus performs a refrigeration cycle in which a high pressure is equal to or greater than the critical pressure of a refrigerant. The refrigeration apparatus performs at least a heat application operation in which an indoor heat exchanger of the refrigerant circuit functions as a radiator. A controller of the refrigeration apparatus controls the opening degree of the indoor expansion valve of the refrigerant circuit so that the temperature of the refrigerant at the outlet of the indoor heat exchanger reaches a predetermined reference temperature, in the heat application operation.

Abstract: A valve mechanism (14a, 14b, 63a, 63b, 90) includes: a valve body (80, 95); a first flow path (81) located opposite a distal end (80a, 95b) of the valve body (80, 95); a driver (85) configured to move the valve body (80, 95) to a first position where the distal end (80a, 95b) of the valve body (80, 95) closes the first flow path (81) and a second position where the distal end (80a, 95b) of the valve body (80) opens the first flow path (81); and a second flow path (82) configured to communicate with the first flow path (81) when the valve body (80) is at the second position. The high-pressure flow path (I1, I2, O2, O3, 48) causes the high-pressure refrigerant to always flow through the second flow path (82) and first flow path (81) of the valve mechanism (14a, 14b, 63a, 63b, 90) in this order.

Abstract: A refrigeration apparatus is of a two-stage compression type for compressing a refrigerant to a supercritical region. The refrigeration apparatus includes a lower stage-side compression unit, a higher stage-side compression unit, an intermediate cooler, a heat source-side heat exchanger, a utilization-side heat exchanger, an economizer circuit, and a control unit. During a first operation in which the heat source-side heat exchanger functions as a radiator and the utilization-side heat exchanger functions as an evaporator, in a case where a discharge temperature which is a temperature of the refrigerant discharged from the higher stage-side compression unit is more than a first temperature, the control unit increases a cooling capacity of the intermediate cooler without increasing a refrigerant flow rate of the economizer circuit on condition that the intermediate cooler does not reach a maximum cooling capacity.

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 switching mechanism (TV1, TV2, TV3, TV4, FV) includes an electric motor (74), a flow path switching portion (71) to be driven by the electric motor (74), a first port (P1) connected to a high-pressure flow path (7, 24, 28b, 31, 32) of a refrigerant circuit (6), a second port (P2) connected to a low-pressure flow path (8, 25, 28a, 33, 34) of the refrigerant circuit (6), and a third port (P3) connected to a predetermined flow path of the refrigerant circuit (6). The switching mechanism (TV1, TV2, TV3, TV4, FV) is switched between a first state in which the first port (P1) communicates with the third port (P3) and a second state in which the second port (P2) communicates with the third port (P3) in such a manner that the electric motor (74) drives the flow path switching portion (71).

Abstract: A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, an oil return pipe that returns the oil discharged by the high-stage compressor to the low-stage compressor, and an oil discharge pipe that discharges the oil in the low-stage compressor. The low-stage compressor includes a compression part that compresses the refrigerant, a motor that drives the compression part, and a container that houses the compression part and the motor. The container forms a high-pressure space storing compressed refrigerant. Inside of the oil return pipe and inside of the oil discharge pipe are connected to the high-pressure space.

Abstract: A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, an intercooler, and an oil discharge pipe. The intercooler cools the refrigerant discharged by the low-stage compressor before the refrigerant is sucked into the high-stage compressor. The intercooler is disposed between the refrigerant pipes. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on an upstream side of the intercooler.

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 flow path switching mechanism (70) includes first to fourth flow paths (71, 72, 73, 74) and opening and closing mechanisms (V1, V2, V3, V4, 75, 76) that can each open and close a corresponding one of the flow paths (71, 72, 73, 74). A first connection point (C1) connecting an inflow portion of the first flow path (71) and an inflow portion of the second flow path (72) is connected to a discharge portion of a compression unit (30). A second connection point (C2) connecting an outflow portion of the first flow path (71) and an inflow portion of the third flow path (73) is connected to a gas-side end of a heat source heat exchanger (22). A third connection point (C3) connecting an outflow portion of the second flow path (72) and an inflow portion of the fourth flow path (74) is connected to a gas-side end of a second utilization heat exchanger (85, 93).

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 refrigeration apparatus controller calculates a refrigeration load of a refrigeration apparatus, and a load signal (S) containing load information indicating a magnitude of the refrigeration load is output from a communication device to an engine controller. The engine controller controls a speed of rotation of a generator engine based on the load signal (S).

Abstract: A refrigerating apparatus includes a casing body attached to an opening formed at one end of a box-shaped cooling compartment so as to close the opening, a refrigeration cycle unit including a compressor and a radiator provided on an outer side of the cooling compartment relative to the casing body and an evaporator provided on an inner side of the cooling compartment relative to the casing body, a diagnosis process executer configured to control the refrigeration cycle unit to execute a diagnosis process for diagnosing a performance of the cooling compartment, and a performance determinator configured to determine the performance of the cooling compartment in the diagnosis process.

Abstract: A refrigerating apparatus includes a casing body attached to an opening formed at one end of a box-shaped cooling compartment so as to close the opening, a refrigeration cycle unit including a compressor and a radiator provided on an outer side of the cooling compartment relative to the casing body and an evaporator provided on an inner side of the cooling compartment relative to the casing body, a diagnosis process executer configured to control the refrigeration cycle unit to execute a diagnosis process for diagnosing a performance of the cooling compartment, and a performance determinator configured to determine the performance of the cooling compartment in the diagnosis process.

Abstract: A refrigeration device includes a switching valve control section for outputting a switching signal for controlling a four-way switching valve to a predetermined switching state when starting a compression mechanism; and a switching determination section which, when starting only a first compressor as a start-up of the compression mechanism, outputs a low differential pressure signal if a differential pressure between a high-pressure port and a low-pressure port in the four-way switching valve falls below a determination value in a determination operation after the switching signal being outputted by the switching valve control section. After the switching determination section outputs the low differential pressure signal, a capacity control section starts a second compressor.

Abstract: A refrigeration apparatus controller calculates a refrigeration load of a refrigeration apparatus, and a load signal (S) containing load information indicating a magnitude of the refrigeration load is output from a communication device to an engine controller. The engine controller controls a speed of rotation of a generator engine based on the load signal (S).