A refrigeration cycle device includes: a refrigerant circuit which circulates a mixed refrigerant containing at least CF3I and HFO1123, the RC including a compressor, an expansion valve, an indoor heat exchanger, an outdoor heat exchanger and a refrigerant reservoir; an injection pipe having a first end at a first height within the refrigerant reservoir and a second end connected to the compressor; and an injection valve included in the injection pipe. The CF3I has the greatest fluid density among refrigerants contained in the mixed refrigerant. The first height is higher than a height at which an end of a refrigerant pipe, other than the injection pipe, is located within the refrigerant reservoir.

Aspects of the present disclosure include a system for turbo-compression cooling. The system may be aboard a marine vessel. The system includes a power cycle and a cooling cycle. The power cycle includes a first working fluid, a waste heat boiler configured to evaporate the working fluid, a turbine, and a condenser. The condenser condenses the working fluid to a saturated or subcooled liquid. The cooling cycle includes a second working fluid, a first compressor configured to increase the pressure of the second working fluid, a condenser configured to condense the second working fluid to a saturated or subcooled liquid after exiting the first compressor, an expansion valve, and an evaporator. The turbine and first compressor are coupled one to the other. The waste heat boiler receives waste heat from engine jacket water and lubricating oil from a ship service generator. The evaporator cools water in a shipboard cooling loop.

A cooling system implements various processes to improve efficiency in high ambient temperatures. First, the system can flood one or more low side heat exchangers in the system. Second, the system can direct a portion of vapor refrigerant from a low side heat exchanger to a flash tank rather than to a compressor. Third, the system can transfer heat from refrigerant at a compressor suction to refrigerant at the discharge of a high side heat exchanger.

A refrigeration cycle device includes a third refrigerant passage connecting a utilization heat exchanger to a first expansion valve, a fourth refrigerant passage connecting the first expansion valve to a receiver, a fifth refrigerant passage connecting the receiver to a second expansion valve, a sixth refrigerant passage connecting the second expansion valve to an air heat exchanger, a hot-gas bypass passage connecting a discharge passage to the sixth refrigerant passage, a hot-gas bypass valve, an internal heat exchanger to exchange heat between the liquid refrigerant inside the receiver and the refrigerant passing through the suction passage, a liquid bypass passage including an inlet portion connected to the fourth refrigerant passage, the fifth refrigerant passage, or a lower portion of the receiver, and an outlet portion connected to the suction passage upstream of the internal heat exchanger, and a liquid bypass valve.

A method of operating a refrigeration and heating system (2a, 2b) comprises: circulating a refrigerant through a refrigeration circuit (4) which comprises in the direction of flow of the circulating refrigerant: at least one compressor (6a, 6b, 6c); a refrigeration circuit side (8a) of a coupling heat exchanger (8); at least one gas cooler (10); at least one expansion device (12, 14); and at least one evaporator (16); circulating a heating fluid through a heating circuit (20) which comprises a heating circuit side (8b) of the coupling heat exchanger (8) and at least one heat consumer (22); wherein the coupling heat exchanger (8) is configured for transferring heat from the circulating refrigerant to the circulating heating fluid. The method further includes increasing the temperature of the refrigerant entering the at least one gas cooler (10) in order to meet increased heating demands by allowing at least a portion of the heating fluid to flow directly from an outlet to an inlet of the heating circuit side (8b) of the coupling heat exchanger (8) bypassing the at least one heat consumer (22) or by allowing at least a portion of the refrigerant circulating through the refrigeration circuit (4) to bypass the coupling heat exchanger (8).

Provided is a heat pump device capable of efficiently adjusting the temperature in a buffer tank for collecting or discharging a refrigerant in a high-pressure space of a refrigerant circulation circuit.

Disclosed is a heat pump device in which a compressor, a gas cooler, a refrigerant heat exchanger, a refrigerant expansion valve, and an evaporator are connected to configure a refrigerant circulation circuit, wherein the heat pump device includes a buffer tank, one end of which is connected to the high-pressure side of the refrigerant expansion valve and arranged to store a refrigerant, and a first refrigerant pipe, one end of which is connected to the high-pressure side of the compressor and the other end of which is connected to the low-pressure side of the evaporator and arranged to exchange heat with the buffer tank, wherein the first refrigerant pipe includes a first control valve arranged between the high-pressure side of the compressor and the buffer tank to control the opening and closing of the first refrigerant pipe, and a first flow rate regulator arranged between the buffer tank and the low-pressure side of the evaporator to control the flow rate of the refrigerant.

The present disclosure relates to the technical field of heat pumps, in particular to an air source CO.sub.2 heat pump system for preventing an evaporator from frosting by using heat of a heat regenerator. The air source CO.sub.2 heat pump system mainly includes an air source heat pump system, a regenerative heat exchange tank and a cooling pump. Through the regenerative heat exchange tank, on the one hand, the temperature drop of regenerative heat of the system is further increased and throttling loss is reduced; on the other hand, the heat generated by the regenerative temperature drop is configured for heat storage used for defrosting, and configured for overheating temperature rise.

A control unit is configured to set a rotation speed of a compressor to be lower than that in a defrosting operation and set an opening degree of a pressure reducing device to be equal to or greater than that in the defrosting operation during a first control time after completion of the defrosting operation, stop the compressor and set the opening degree of the pressure reducing device to be less than that in the first control time during a second control time after lapse of the first control time, and control a refrigerant circuit switching device to resume a heating operation after lapse of the second control time.

In one aspect, an air conditioning system is provided. The air conditioning system includes a refrigeration circuit having a refrigerant and an economizer circuit, and a subcooling circuit thermally coupled to the refrigeration circuit, the subcooling circuit including a thermal energy storage (TES) unit and a phase change material (PCM) for thermal exchange with the refrigerant.

A system includes a first heat exchanger, a flash tank, a first compressor, a condenser, a second heat exchanger, and a second compressor. The first heat exchanger removes heat from carbon dioxide refrigerant. The flash tank stores the carbon dioxide refrigerant from the first heat exchanger. The first compressor compresses the carbon dioxide refrigerant and sends the compressed carbon dioxide refrigerant to the first heat exchanger. The condenser removes heat from a second refrigerant. The second heat exchanger receives the second refrigerant from the condenser. The second heat exchanger further removes heat from the carbon dioxide refrigerant stored in the flash tank. The second compressor compresses the second refrigerant from the heat exchanger. The second compressor sends the second refrigerant to the condenser.