A system has: a compressor having a suction port and a discharge port; an ejector having a motive flow inlet, a suction flow inlet, and an outlet; a separator having an inlet, a vapor outlet, and a liquid outlet; a first heat exchanger; an expansion device; and a second heat exchanger. Conduits and valves are positioned to provide alternative operation in: a cooling mode and a heating mode. In the cooling mode, a needle of the ejector is closed. In the heating mode refrigerant passes sequentially from a first section of the second heat exchanger to a second section. In the cooling mode refrigerant passes in parallel through the first section and the second section.

A CO.sub.2 cooling system includes a compression stage in which CO.sub.2 refrigerant is compressed; a cooling stage in which the CO.sub.2 refrigerant releases heat; a CO.sub.2 liquid receiver in which the CO.sub.2 refrigerant is accumulated in liquid and gaseous states; an evaporation stage in which the CO.sub.2 refrigerant, having released heat in the cooling stage, absorbs heat. The evaporation stage has first and second evaporation sectors; a first metering device for feeding CO.sub.2 refrigerant into the first evaporation sector at a first pressure; and a second metering device for feeding CO.sub.2 refrigerant into the second evaporation sector at a second pressure. The first metering device and the second metering device are operated independently from one another. A plurality of CO.sub.2 transfer lines connects the compression stage, the cooling stage, the CO.sub.2 liquid receiver and the evaporation stage. The CO.sub.2 refrigerant is circulable in a closed-loop circuit.

A CO.sub.2 cooling system includes a compression stage in which CO.sub.2 refrigerant is compressed; a cooling stage in which the CO.sub.2 refrigerant releases heat; a CO.sub.2 liquid receiver in which the CO.sub.2 refrigerant is accumulated in liquid and gaseous states; an evaporation stage in which the CO.sub.2 refrigerant, having released heat in the cooling stage, absorbs heat. The evaporation stage has first and second evaporation sectors; a first metering device for feeding CO.sub.2 refrigerant into the first evaporation sector at a first pressure; and a second metering device for feeding CO.sub.2 refrigerant into the second evaporation sector at a second pressure. The first metering device and the second metering device are operated independently from one another. A plurality of CO.sub.2 transfer lines connects the compression stage, the cooling stage, the CO.sub.2 liquid receiver and the evaporation stage. The CO.sub.2 refrigerant is circulable in a closed-loop circuit.

A heat exchanger includes a heat exchanging portion, a reservoir that performs gas-liquid separation on a gas-liquid two-phase refrigerant that flows out from the heat exchanging portion into a gas-phase refrigerant and a liquid-phase refrigerant and stores the liquid-phase refrigerant, and an inflow passage that allows the gas-liquid two-phase refrigerant flowing out from the heat exchanging portion to flow into the reservoir. The inflow passage is connected so as to be in communication with an inlet port of the reservoir which is disposed above a liquid surface of the liquid-phase refrigerant stored in the reservoir.

Thermal management systems are described. These systems include a refrigerant receiver configured to store a refrigerant fluid, an evaporator, a closed-circuit refrigeration system having a closed fluid circuit path, with the refrigerant receiver and evaporator disposed in the closed fluid circuit path, and the closed fluid circuit path including a condenser and compressor. These systems also include a modulation capacity control circuit configured to selectively divert refrigerant vapor flow to the condenser from the compressor by diverting a portion of refrigerant vapor flow (diverted flow) from the compressor to the refrigerant receiver in accordance with cooling capacity demand. These systems also include an open-circuit refrigeration system having an open fluid circuit path with the refrigerant receiver and the evaporator, and an exhaust line that discharges the refrigerant fluid from the exhaust line so that the discharged refrigerant fluid is not returned to the open-circuit and the closed-circuit refrigerant fluid flow paths.

Thermal management systems are described. These systems include a refrigerant receiver configured to store a refrigerant fluid, an evaporator, a closed-circuit refrigeration system having a closed fluid circuit path, with the refrigerant receiver and evaporator disposed in the closed fluid circuit path, and the closed fluid circuit path including a condenser and compressor. These systems also include a modulation capacity control circuit configured to selectively divert refrigerant vapor flow to the condenser from the compressor by diverting a portion of refrigerant vapor flow (diverted flow) from the compressor to the refrigerant receiver in accordance with cooling capacity demand. These systems also include an open-circuit refrigeration system having an open fluid circuit path with the refrigerant receiver and the evaporator, and an exhaust line that discharges the refrigerant fluid from the exhaust line so that the discharged refrigerant fluid is not returned to the open-circuit and the closed-circuit refrigerant fluid flow paths.

A cooling system includes a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide, a mixer configured to generate mixed refrigerant in which the pressurized carbon dioxide and solvent in a liquid state, a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant, a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled, and a second heat exchanger configured to cool the carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant.

A cooling system includes a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide, a mixer configured to generate mixed refrigerant in which the pressurized carbon dioxide and solvent in a liquid state, a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant, a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled, and a second heat exchanger configured to cool the carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant.

An economizer and an air conditioning system. The economizer includes a housing with a refrigerant inlet for connecting to a first heat exchanger, a refrigerant outlet for connecting to a second heat exchanger, and a suction port for connecting to an intermediate stage of a compressor provided thereon; and a choke portion configured to protrude inwardly from an inner wall of the housing and arranged close to the suction port, such that refrigerant flowing to the suction port is at least partially obstructed. According to the technical solutions of the present application, the refrigerant flowing to the suction port can be at least partially obstructed. When the liquid droplets carried by the refrigerant are obstructed by the choke portion, the liquid droplets are adsorbed on the wall surface to form a liquid film, and the movement of the liquid film is obstructed by the choke portion.

A rotary compressor (1) includes a hermetically sealed compressor housing (10) that is provided with a refrigerant discharge portion (107) and refrigerant suction portions (104, 105), a compression unit (12) that is arranged in the compressor housing (10) and compresses a refrigerant, sucked from the suction portions (104, 105), and discharges it from the discharge portion (107), a motor (11) that is arranged in the compressor housing (10) and drives the compression unit (12), an accumulator that is connected to the suction portions (104, 105), and a mounting member (50) that secures the accumulator to the compressor housing (10). The compressor housing (10) and an accumulator container (26) of the accumulator are made of a metal material. The mounting member (50) is at least partially made of a resin material and has a first joint portion (J1), which is joined to an outer peripheral surface (10a) of the compressor housing (10).