Disclosed is a CO.sub.2 based refrigeration system including a condenser for transferring heat from a CO.sub.2 refrigerant of the refrigeration system to an air stream. The system further includes a metering device downstream of the condenser and a bypass arrangement. The metering device is configured to create a pressure drop so that part of the refrigerant liquifies, when received in a supercritical state, from the condenser such that a liquid component and a flash gas component are generated. The bypass arrangement includes a valve and a bypass line to allow the refrigerant to bypass the metering device.

The invention relates to an apparatus (112) and to a method (210) for generating cryogenic temperatures. The apparatus (112) comprises at least one cooling stage (111) which has a cold region (110) and a warm region (116), and a refrigerant mixture designed specifically for the cooling stage (111) is provided in the warm region (116), the refrigerant mixture having at least two components each having a different boiling temperature, and the cold region (110) comprises at least one cooling stage (111): - a first heat exchanger (122), which has a high-pressure side (120) to receive the refrigerant mixture at a high-pressure level from the warm region (116) of the cooling stage (111) and a low-pressure side (126) to deliver the refrigerant mixture to the warm region (116) of the cooling stage (111); - a first expansion device (136), which is designed for expansion and for cooling of the refrigerant mixture at a low-pressure level; - a second heat exchanger (148), which is designed for cooling and for partial condensation of a proportion of the refrigerant mixture located in a buffer volume (140), the buffer volume (140) being designed to limit the pressure exerted by the refrigerant mixture; and - a second expansion device (150), which is designed for separation of the buffer volume (140) from the low-pressure level of the cooling stage (111) or connection of the buffer volume (140) to said low-pressure level. The invention enables autonomous operation of the apparatus (112) and of the method (210) for generating cryogenic temperatures, in which each cooling stage (111) of the apparatus (112) can be filled with a pre-defined refrigerant mixture and can be permanently operated, and in particular in the cooling phase the refrigerating capacity can be increased, while incorrect distribution of the refrigerant of the relevant cooling stage (111) among parallel flow channels at the cold end of the first heat exchanger (122) can be prevented.

The invention relates to an apparatus (112) and to a method (210) for generating cryogenic temperatures. The apparatus (112) comprises at least one cooling stage (111) which has a cold region (110) and a warm region (116), and a refrigerant mixture designed specifically for the cooling stage (111) is provided in the warm region (116), the refrigerant mixture having at least two components each having a different boiling temperature, and the cold region (110) comprises at least one cooling stage (111): - a first heat exchanger (122), which has a high-pressure side (120) to receive the refrigerant mixture at a high-pressure level from the warm region (116) of the cooling stage (111) and a low-pressure side (126) to deliver the refrigerant mixture to the warm region (116) of the cooling stage (111); - a first expansion device (136), which is designed for expansion and for cooling of the refrigerant mixture at a low-pressure level; - a second heat exchanger (148), which is designed for cooling and for partial condensation of a proportion of the refrigerant mixture located in a buffer volume (140), the buffer volume (140) being designed to limit the pressure exerted by the refrigerant mixture; and - a second expansion device (150), which is designed for separation of the buffer volume (140) from the low-pressure level of the cooling stage (111) or connection of the buffer volume (140) to said low-pressure level. The invention enables autonomous operation of the apparatus (112) and of the method (210) for generating cryogenic temperatures, in which each cooling stage (111) of the apparatus (112) can be filled with a pre-defined refrigerant mixture and can be permanently operated, and in particular in the cooling phase the refrigerating capacity can be increased, while incorrect distribution of the refrigerant of the relevant cooling stage (111) among parallel flow channels at the cold end of the first heat exchanger (122) can be prevented.

A gas injection-type heat-management system includes a base flow path sequentially provided with a compressor, an inner condenser, a heat exchanger, a first expansion valve, an outer condenser, a second expansion valve, and an evaporator, a heat exchange flow path branched from the base flow path at an upstream point of the heat exchanger, disposed to be heat-exchangeable with the base flow path in the heat exchanger by passing through a third expansion valve, and joined to the base flow path on the compressor or at an upstream point thereof, a first bypass flow path connected to the base flow path, a second bypass flow path connected to the base flow path, and a recirculation flow path branched from the base flow path at a downstream point of the outer condenser and joined to the heat exchange flow path at an upstream point of the third expansion valve.

The present invention provides a vapor injection module including a first expansion means configured to block a flow of a condensed refrigerant or expand the condensed refrigerant and transmit the refrigerant to a gas-liquid separator in accordance with an air conditioning mode, the gas-liquid separator configured to receive the refrigerant from the first expansion means and separate the refrigerant into a gaseous refrigerant and a liquid refrigerant, and a second expansion means configured to allow the condensed refrigerant to pass therethrough, expand the condensed refrigerant, or expand the liquid refrigerant separated in the gas-liquid separator in accordance with the air conditioning mode.

A refrigeration cycle device is configured to be selectively switchable between an air-cooling first refrigerant circuit that causes refrigerant to flow out of a liquid-phase refrigerant outlet of a gas-liquid separator, and an air-heating second refrigerant circuit that causes the refrigerant to flow out of a gas-phase refrigerant outlet of the gas-liquid separator. In the refrigeration cycle device, an oil separator is disposed in a refrigerant passage that leads from a heat dissipation device to a first expansion valve. Thus, when the first refrigerant circuit is configured in the refrigeration cycle device, the refrigerant passing through the oil separator is in a single gas phase or in an almost gas phase, so that oil can be easily separated from the refrigerant. Furthermore, when the refrigerant circulates through the first refrigerant circuit, oil can be retained at a position other than the gas-liquid separator.

A refrigeration cycle device according to the present invention includes a compressor having a first compression chamber and a second compression chamber, a condenser, a decompressor, an evaporator, an injection path configured to introduce intermediate pressure refrigerant, a communication passage configured to introduce intermediate pressure refrigerant compressed in the first compression chamber to the second compression chamber, and a switch element configured to selectively make the second compression chamber communicate with the evaporator or make the second compression chamber communicate with the communication passage. The injection path introduces the intermediate pressure refrigerant to the second compression chamber. Single-stage compressing operation is performed when the second compression chamber is communicated with the evaporator, and two-stage compressing operation is performed when the second compression chamber is communicated with the communication passage.

A heat pump system for a vehicle, which makes refrigerant bypass an external heat exchanger and turns off a fan mounted on the external heat exchanger when temperature of the outdoor air is lower than setting temperature and the vehicle enters into an idle state in a heat pump mode, thereby continuously operating the heat pump mode even in the below zero temperature so as to keep heating performance, reducing consumption of electrical power without needing to operate an electric heater, and preventing excessive noise of a fan when the vehicle enters into an idle state in the below zero temperature.

A thermal management system for a vehicle includes a base circuit in which a compressor, a condenser, an expansion valve, and an evaporator are provided in order and in which a refrigerant is circulated, a recirculation circuit branched from a discharge portion of the compressor in the base circuit and joined to an inlet portion of the compressor so that the refrigerant discharged from the compressor is recirculated to an inlet of the compressor, and an adjusting valve positioned at the discharge portion where the recirculation circuit is branched from the base circuit or positioned at the inlet portion where the recirculation circuit is joined to the base circuit, the adjusting valve configured to adjust a flow rate of the refrigerant that flows to the recirculation circuit.

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).