A reverse compression cycle machine includes an evaporator, a compressor and a condenser arranged in series along a path of a working fluid in the machine, further including a boundary layer turbine placed between the condenser and the evaporator. The turbine includes a set of power disks mounted on a shaft which rotates inside a volume of a rotor casing, an inlet opening for introducing a working fluid in a stator volume, a stator nozzle, which accelerates the flow in a direction that is tangential to the power disks, and a discharge of a working fluid. The rotor casing includes a drain of a liquid fraction of the working fluid from the peripheral part of the power disks in order to avoid its concentration in the peripheral part of the volume of the rotor casing.

A method of initiating a low-energy cooling mode using a controller of an HVAC system includes measuring a temperature of ambient air proximal to a condenser coil and determining whether the temperature of the ambient air proximal the condenser coil is less than a temperature threshold. If the temperature of the ambient air is less than the temperature threshold, the HVAC system is configured to operate in a low-energy cooling mode. In the low-energy cooling mode, the controller opens a first bypass valve to allow a refrigerant to bypass a compressor and the compressor is powered off. The HVAC system is operated until a cooling demand has been met.

An integrated air conditioning system having a first air conditioning unit having a first evaporator with a first input and a first output; a second air conditioning unit having a second evaporator with a second input and a second output; a first conduit fluidly connecting the first input with the second output; a second conduit fluidly connecting the second input with the first output. The first and second conduits and the first and second evaporators form a working fluid circuit.

A refrigeration system includes an evaporator, a condenser, a compressor, a capillary tube, and an expansion device. The compressor is configured to circulate a refrigerant between the evaporator and the condenser. The capillary tube is configured to receive the refrigerant from the condenser. The expansion device is configured to receive the refrigerant from the capillary tube and provide the refrigerant to the evaporator. The expansion device is adjustable to control a flow of the refrigerant through the capillary tube.

A defrost method for a heat pump system includes running the heat pump system in a heating mode to provide heat to an enclosed space and determining if an outdoor temperature is less than an outdoor threshold temperature. Responsive to a determination that the outdoor temperature is below the outdoor threshold temperature, determining if a calibration state has been previously run. Responsive to a determination that the calibration state has not been previously run, running the heat pump system in the calibration state. Responsive to a determination that the calibration state has been previously run, determining if a temperature difference between a temperature of an evaporator coil of the heat pump system and the outdoor temperature exceeds a temperature threshold value. Responsive to a determination that the temperature difference between the evaporator coil and the outdoor temperature is greater than the temperature threshold value, running the heat pump system in a defrost state.

A heating, ventilation, and air-conditioning (“HVAC”) system for use with a refrigerant. The HVAC system includes a compressor, a condenser, an evaporator expansion device, and an evaporator. The HVAC system also includes a thermal energy storage device (“TESD”) including thermal energy storage media in line between the condenser and evaporator. A control system is programmed to operate the compressor and the evaporator expansion device to control the refrigerant flow through the HVAC system. The control system is also programmed to control the refrigerant flow through the TESD to charge the TESD with thermal energy. The control system is also programmed to control the refrigerant flow through the evaporator expansion device and evaporator and discharge the thermal energy from the charged TESD to improve the performance of the HVAC system.

A battery temperature control system includes: a refrigeration cycle including a compressor and a heat exchanger; an accumulator; a condenser; a bypass for supplying refrigerant discharged from the compressor to the heat exchanger while bypassing the condenser; a valve mechanism; a temperature detector; a controller configured to switch the valve mechanism; and an introduction passage branched off from a passage extending from a discharge port of the compressor to a position in the refrigeration cycle upstream of the heat exchanger. The introduction passage supplies the refrigerant reduced in pressure to a part of a passage extending from a position in the refrigeration cycle downstream of the accumulator or downstream of the heat exchanger to a position in the refrigeration cycle upstream of the accumulator. The controller adjusts an opening degree of the variable throttle disposed in the introduction passage depending on a temperature detected by the temperature detector.

In an air-conditioning system including a thermal storage heat exchanger, a refrigerant circuit is configured such that an indoor heat exchanger and a receiver communicate with the thermal storage heat exchanger when an operational mode of the refrigerant circuit is switched to a cooling operation in which the thermal storage heat exchanger serves as a radiator and the indoor heat exchanger serves as an evaporator.

A refrigerant leakage determination system capable of detecting leakage of refrigerant without requiring complicated processing is provided. A refrigerant leakage determination system is a refrigerant leakage determination system of a refrigeration cycle apparatus that includes a refrigerant circuit including a heat-source-side heat exchanger and has, as operating modes, a normal mode in which the heat-source-side heat exchanger is caused to function as an evaporator and a defrosting mode in which the heat-source-side heat exchanger frosted during a normal operation is defrosted. The refrigerant leakage determination system includes a processor configured to acquire defrosting information regarding a relationship between a normal operation period and the number of defrosting operations, and memory that stores the defrosting information. The processor is further configured to determine, based on the acquired defrosting information, leakage of refrigerant in the refrigerant circuit.

The invention relates to a refrigerant for a cooling device (10) comprising a cooling circuit (11) comprising at least one heat exchanger (12), the refrigerant undergoing a phase transition in the heat exchanger, the refrigerant being a refrigerant mixture composed of a fraction of carbon dioxide (CO.sub.2), a fraction of 1,1-difluoroethene and a fraction of at least one other component, wherein the fraction of carbon dioxide in the refrigerant mixture is 45 to 90 mole percent, the fraction of 1,1-difluoroethene being 5 to 40 mole percent.