Climate control systems and methods of operating them are provided that circulate a working fluid including a high glide refrigerant blend having first and second refrigerants with a difference in boiling points ≥about 25° F. at atmospheric pressure. The system includes a gas-liquid separation vessel that generates a vapor stream and a liquid stream. A compressor receives the vapor stream and generates a pressurized vapor stream. A liquid pump receives the liquid stream and generates a pressurized liquid stream. A condenser is disposed downstream of the compressor and liquid pump and receives and cools the pressurized mixed vapor and liquid stream. An evaporator receives and at least partially vaporizes the multiphase working fluid and directs it to the gas-liquid separating vessel. An expansion device between the condenser and the evaporator processes the multiphase working fluid stream. Lastly, a fluid conduit for circulating the working fluid through the components is provided.

An integrated system floods an air conditioning low side heat exchanger such that the air conditioning low side heat exchanger does not evaporate all the liquid refrigerant entering the air conditioning low side heat exchanger. As a result, both liquid and vapor refrigerant leave the air conditioning low side heat exchanger. The system includes an additional receiver that stores the refrigerant leaving the air conditioning low side heat exchanger. To prevent the liquid refrigerant in the receiver from overflowing, the liquid refrigerant in the receiver is used in a refrigeration system when the level of liquid refrigerant in the receiver exceeds a threshold (e.g., as detected by a sensor in the receiver).

A heat source-side unit (10) includes a heat source-side circuit (11). The heat source-side circuit (11) includes a compression unit (20) including a lower-stage compression element (23) and a higher-stage compression element (21), an intermediate heat exchanger (17) disposed on a refrigerant path between the lower-stage compression element (23) and the higher-stage compression element (21), and a bypass passage (23c) connected to a suction pipe (23a) and a discharge pipe (23b) each connected to the lower-stage compression element (23). At startup of the compression unit (20), a first action is performed for stopping the lower-stage compression element (23) and operating the higher-stage compression element (21). This configuration thus suppresses occurrence of liquid compression at startup of a compressor.

A refrigerant cycle system includes: a first refrigerant circuit that includes a first heat exchanger, a first compressor, and a first cascade heat exchanger and that is configured as a first vapor compression refrigeration cycle; a second refrigerant circuit that includes the first cascade heat exchanger, a second compressor, and a second heat exchanger and that is configured as a second vapor compression refrigeration cycle; a first unit that accommodates the first heat exchanger and the first compressor; a second unit that accommodates the first cascade heat exchanger and the second compressor; and a third unit that accommodates the second heat exchanger. The first unit, the second unit, and the third unit are disposed apart from each other. The first cascade heat exchanger performs heat exchange between a first refrigerant that flows through the first refrigerant circuit and a second refrigerant that flows through the second refrigerant circuit.

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 heating and cooling system powered by renewable energy and assisted with geothermal energy includes a solar cycling unit, a supercritical carbon dioxide (S—CO.sub.2) unit, and a refrigerant cycling unit. Solar energy obtained at the solar cycling unit may be used to power the S—CO.sub.2 cycling unit. To do so, the solar cycling unit utilizes a solar collector, a thermal energy storage, and a heat exchanger along with a first working fluid which is preferably molten salt or Therminol. Next, the energy generated at the S—CO.sub.2 cycling unit, which preferably circulates S—CO.sub.2 as a second working fluid, may be used to operate the refrigerant cycling unit. In the refrigerant cycling unit, Tetrafluroethene is preferably used as the third working fluid to produce required cooling effects. Additionally, geothermal heat exchangers may be integrated into the system for use during varying weather conditions.

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 cooling system for a cryochamber comprises compressors, heat exchangers and flow restrictions. Compressors are used to pressurize the working fluid, heat exchangers are used to release the heat to the ambient, absorb heat from the interior of the cryochamber to decrease the temperature inside the cryochamber, to cool the working fluid below the ambient temperature using source of cold or to recuperate heat of the cold working fluid stream. Flow restrictions are used to decrease the pressure of the working fluid which results in its temperature decrease. Cryochambers are used for whole-body cryotherapy and require cooling systems that are able to lower the air temperature inside the cryochamber to −90° F.

Thermoelectric enhanced hybrid heat pump systems are provided herein. A compressor increases the pressure of refrigerant within tubing. A first heat exchanger is downstream of the compressor and changes enthalpy of first fluid flow through heat exchange with refrigerant. A second heat exchanger changes enthalpy of second fluid flow through heat exchange with refrigerant. A thermoelectric device is downstream of the first heat exchanger and reduces refrigerant temperature. Expansion valves are downstream of the thermoelectric device and first heat exchanger, respectively located on first and second sides of the thermoelectric device, and expand refrigerant and reduce refrigerant pressure while conserving refrigerant enthalpy. At least one valve reverses refrigerant flow within the tubing without changing compressor operation. A control system controls the thermoelectric device and at least one valve to switch the heat pump system from heating mode to cooling mode and from cooling mode to heating mode.

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.