Abstract: A refrigeration cycle may include a compressor and a flash tank. The flash tank is configured for receiving a refrigerant and separating liquid refrigerant and vapour refrigerant. The compressor is configured for compressing the refrigerant and includes a suction port and an injection port. The flash tank is connected to the injection port of the compressor via an injection valve. A method of controlling injection into the compressor includes determining a pressure in the flash tank and controlling the injection valve based on the determined pressure in the flash tank.

Abstract: A compressor comprises a suction port configured to receive a refrigerant and means for compressing the refrigerant. The means for compressing forms at least one compression chamber, a discharge port configured for discharging the compressed refrigerant from the compressor, and a motor. The means for compressing comprises at least one opening for extracting a portion of the refrigerant from the at least one compression chamber and supplying the extracted portion of the refrigerant to the motor. A method comprises receiving a refrigerant at a suction port of the compressor, compressing the refrigerant in at least one compression chamber formed by a means for compressing of the compressor, discharging the refrigerant from the compressor at a discharge port of the compressor, and extracting a portion of the refrigerant from the at least one compression chamber and supplying the extracted portion of the refrigerant to a motor of the compressor.

Abstract: A method of controlling injection into a compressor in a refrigeration cycle is described. A refrigeration cycle may comprise at least an economizer heat exchanger, a heat rejection heat exchanger, a first expansion device, and a compressor. A discharge port of the compressor is connected to the heat rejection heat exchanger via a discharge line and an injection port of the compressor is connected to the means for compressing. The economizer heat exchanger comprises a first path having an input connected to the heat rejection heat exchanger and an output connected to the first expansion device, and a second path having an input connected to the heat rejection heat exchanger via an economizer valve and an output connected to the injection port of the compressor via an injection line. The economizer valve is regulated based on a superheat level of the refrigerant in the economizer heat exchanger.