A cooling device using a refrigeration cycle in which a refrigerant is circulated through a heat receiver, a compressor, a heat radiator, and an expansion valve includes: a gas-liquid separator configured to perform gas-liquid separation on the refrigerant supplied from the expansion valve; a pump configured to send a liquid phase refrigerant separated by the gas-liquid separator to the heat receiver; and a control unit configured to control opening and closing of a refrigerant flow path of the refrigeration cycle, and an operation and stop of the compressor and the pump, wherein the control unit starts the operation of the pump on condition that a net positive suction head of the pump has reached a predetermined value or more.

An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

A method for controlling a valve arrangement (12), e.g. in the form of a three way valve, in a vapour compression system (1) is disclosed, the vapour compression system (1) comprising an ejector (6). The valve arrangement (12) is arranged to supply refrigerant to a compressor unit (2) from the gaseous outlet (11) of a receiver (7) and/or from the outlet of an evaporator (9). The vapour compression system (1) may be operated in a first mode of operation (summer mode) or in a second mode of operation (winter mode). When operated in the second mode of operation, it is determined whether or not conditions for operating the vapour compression system (1) in the first mode of operation are prevailing. If this is the case, the valve arrangement (12) is actively switched to the first mode of operation by closing a first inlet (13) towards the evaporator (7) and fully opening a second inlet (14) towards the receiver (7).

A non-condensable gas purge system is configured to be used in a chiller system that uses a low pressure refrigerant in a loop refrigeration circuit. The non-condensable gas purge system includes a purge tank and a purge heat exchanger coil arranged inside the purge tank. The purge tank has a tank inlet for receiving the low pressure refrigerant from a condenser of the refrigeration circuit, a tank outlet for returning the low pressure refrigerant to an evaporator of the refrigeration circuit, and a purge outlet for purging non-condensable gas from the purge tank to the ambient atmosphere. The purge heat exchanger coil is fluidly connected to the loop refrigeration circuit such that the low pressure refrigerant contained in the loop of the chiller system can pass through the purge heat exchanger coil. Refrigerant in the purge tank is condensed by the heat exchanger coil while non-condensable gases remain gaseous.

A refrigerating apparatus includes a centrifugal compressor, a capacity control mechanism that controls a capacity of the compressor by changing an opening degree of the capacity control mechanism, an expansion mechanism that reduces a pressure of a refrigerant, and a controller. The controller calculates an opening degree of the expansion mechanism using compressor capacity as one of a plurality of indices of change in load. The compressor capacity is obtained from a current rotation number of the compressor, an opening degree of the capacity control mechanism, and a divergence rate of a current operation head from a surge region.

Provided is a refrigeration apparatus which can reduce outlet pressure of a refrigerator even in overload conditions and which can improve refrigeration capacity by liquefying a refrigerant in an intermediate cooler. When outlet pressure of a refrigerator 2 is higher than critical pressure, a control apparatus 60 performs control to reduce the opening degree of a decompression electric valve 31 at the upstream side of an intermediate cooler 30. Thereby, the refrigerant is liquefied by gas-liquid separation in the intermediate cooler 30, so that the refrigerator outlet pressure is made less than the critical pressure, and the liquid refrigerant can be sent to a showcase 3. As a result, the specific enthalpy of the refrigerant at the inlet side of main diaphragm means 41 of the showcase 3 can be reduced, and thereby, the cooling effect can be increased.

A cooling system is designed to operate in two different modes. Generally, in the first mode, when parallel compression is needed, certain valves are controlled to direct gaseous refrigerant from a tank to a compressor in the system and to direct refrigerant from low side heat exchangers towards other compressors. In this manner, a compressor in the system is transitioned to be generally a parallel compressor. In the second mode, when parallel compression is not needed, the valves are controlled to return the refrigerant flow back to normal.

A refrigeration cycle apparatus comprises: a compressor; a first heat exchanger; a second heat exchanger; a first decompressing apparatus; an oil separator; a first circulation pathway in which a refrigerant circulates in an order of the compressor, the first heat exchanger, the oil separator, the first decompressing apparatus, and the second heat exchanger; an oil-returned pathway connecting between the oil separator and a suction side of the compressor; a second decompressing apparatus provided in the oil-returned pathway; and a controller configured to control the first decompressing apparatus and the second decompressing apparatus. The controller is configured to set an operation mode to an oil collection mode by adjusting a degree of decompression of the first decompressing apparatus and a degree of decompression of the second decompressing apparatus when the refrigerant and a refrigerating machine oil flowing in the first circulation pathway are separated in the oil separator.

An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

A cooling system is designed to operate in two different modes. Generally, in the first mode, when parallel compression is needed, certain valves are controlled to direct gaseous refrigerant from a tank to a compressor in the system and to direct refrigerant from low side heat exchangers towards other compressors. In this manner, a compressor in the system is transitioned to be generally a parallel compressor. In the second mode, when parallel compression is not needed, the valves are controlled to return the refrigerant flow back to normal.