A thermal management system includes a refrigerant receiver configured to store a refrigerant fluid, an evaporator arrangement that removes heat from a heat load converting a portion of the refrigerant fluid to refrigerant vapor and a liquid separator having an inlet, a liquid side outlet, and a vapor side outlet. The system also includes a pump that pumps refrigerant liquid received from the liquid side outlet of the liquid separator and a closed-circuit refrigeration system having a closed-circuit fluid path that includes the refrigerant receiver, the liquid separator, the pump, and the evaporator arrangement, the closed-circuit refrigeration system further including a compressor and a condenser. The system also including an open-circuit refrigeration system having an open-circuit fluid path that includes the refrigerant receiver, the liquid separator, the pump, and the evaporator arrangement, and further including a back-pressure regulator configured to receive refrigerant vapor from the vapor side outlet of the liquid separator and an exhaust line coupled to the outlet of the back-pressure regulator, with refrigerant vapor from the exhaust line not returning to the refrigerant receiver.

In order to provide climate control system for heating or cooling a space, in particular a vehicle interior, having a compressor for conveying a refrigerant, which can efficiently use the refrigerant CO.sub.2 for heat pump applications as well, it is proposed to arrange a high-pressure chiller for cooling the refrigerant downstream of the compressor and a low-pressure chiller for heating the refrigerant upstream of the compressor, wherein a refrigerant exiting from the high-pressure chiller can be supplied to a motive mass inlet of a first ejector and a refrigerant exiting from the low-pressure chiller can be supplied to a suction mass inlet of the first ejector, and wherein an outlet of the first ejector is connected directly or indirectly to a liquid separator.

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 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.

A refrigeration system includes an evaporator configured to receive a flow of refrigerant and transfer heat into the refrigerant within the evaporator to provide cooling for a temperature-controlled space, an expansion valve operable to modulate the flow of refrigerant into the evaporator, a liquid level sensor configured to measure a level of liquid accumulated within a component of the refrigeration system, and a controller configured to operate the expansion valve to increase the flow of refrigerant into the evaporator or decrease the flow of refrigerant into the evaporator based on the level of liquid measured by the liquid level sensor.

A refrigeration system operable in cooling mode and defrosting mode is provided. The refrigeration system includes a defrost line connecting a first reservoir to an evaporation stage for conveying at least part of the flash gas from the first reservoir to the evaporation stage when the refrigeration system is operating in defrosting mode. The flash gas thereby releases heat in the evaporation stage for defrosting the evaporation stage. The refrigeration system can also include a discharge line connecting the evaporation stage to a second reservoir.

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 heat exchanger includes heat exchange fins, refrigerant pipes are arranged across the heat exchange fins, and connecting pipes connected to the refrigerant pipes to thereby define refrigerant passages. The connecting pipes include a first pipe portion having a first end connected to one of the refrigerant pipes, a branch pipe portion that is branched from the first pipe portion, that extends parallel to the first pipe portion, and that is connected to another of the refrigerant passages, and a second pipe that is connected to the first pipe portion and that is configured to guide gas-phase refrigerant separated from the refrigerant in the first pipe portion. The second pipe includes an inner insert portion inserted into a second end of the first pipe portion and an outlet portion that extends from the inner insert portion in direction opposite to the second end of the first pipe portion.

A multi-outdoor unit parallel type non-reversing defrosting system, which includes an indoor heat exchanger and three or more outdoor units arranged in parallel. The outdoor units each include a compressor, a four-way valve, an outdoor heat exchanger, a first solenoid valve, and a bypass branch. Two ends of the bypass branch are respectively in bypass connection with a pipeline between the four-way valve and the outdoor heat exchanger and a pipeline between the first solenoid valve and the indoor heat exchanger. The bypass branch is provided with a second solenoid valve configured to control connection and disconnection of the bypass branch. When it is monitored that any outdoor unit is abnormal in frosting, the outdoor units which are not frosted are correspondingly distributed and started as required on the basis of a current heating energy requirement A of the indoor heat exchanger.