A method for determining discharge pressure for a compressor operatively connected to a condenser, an expansion device, and an evaporator in a serial relationship, includes receiving information indicative of a compressor torque or compressor current; and determining a discharge pressure in response to the receiving of the information.

A Brayton cycle type refrigerating apparatus using multiple stages of compressors and having a good response without reduction in efficiency due to change in heat load of the object to be cooled is provided. The Brayton cycle type refrigerating apparatus includes on a refrigerant line on which multiple stages of compressors are arranged in series. The apparatus also includes a temperature sensor for detecting heat load of an object to be cooled and a buffer tank provided between a low pressure line and a high pressure line. A flow rate of the refrigerant in the refrigerant line is controlled by controlling opening degrees of valves to adjust the cooling capacity.

A method of operating a heat pump system comprising: operating the heat pump system in a demand operation heating mode, wherein the demand operation heating mode comprises controlling an opening amount of an expansion valve based on a superheat difference between a compressor inlet superheat value and a target compressor inlet superheat value, and controlling a flowrate of the refrigerant through a compressor based on a thermal demand difference between a thermal output of the indoor heat exchanger and a customer thermal demand; monitoring with the one or more controllers a parameter of the refrigerant cycle indicative of a charge imbalance condition; and transitioning operation with the one or more controllers to a charge compensation mode when the parameter satisfies a first threshold condition, wherein the charge compensation mode comprises performing with the one or more controllers a charge imbalance mitigation strategy.

Systems and methods for heating and cooling an interior space using a heat pump and an air duct system are provided. The heat pump system may be a split system with an indoor heat exchanger and an outdoor heat exchanger. The outdoor heat exchanger may have a volume capacity for holding a fluid such as refrigerant that is significantly larger than that of the indoor heat exchanger. In the heating cycle, the fluid may backup in the heat pump due to the difference in volume capacity between the heat exchangers. To accommodate the excess fluid, the heat pump may include a charge storage vessel. In one example, during a heating cycle, the charge storage vessel and the indoor coils may together serve as the condenser. The charge storage vessel may then prevent and/or relieve pressure build up in the compressor, which could negatively impact efficiency of the heat pump.

A cooling circuit for a system for supplying and cooling a gas in a floating structure having a tank, the cooling circuit having a coolant flowing through it and including a main loop having: a compression device; a heat exchanger; an internal heat exchanger; and a turbocompressor, the cooling circuit includes a regulating branch connected to the main loop, the regulating branch having a valve that is configured to control the flow of coolant within the regulating branch, the main loop including a pressure sensor, the valve controlling the amount of coolant present in the main loop according to the pressure measured by the pressure sensor.

A heat exchanger of flooded type, having: a primary tube bundle, inside which a first hot operating fluid to be cooled down flows; a skirt, circumscribed to the primary tube bundle, which receives a second cold operation fluid which laps against the primary tube bundle in order to subtract heat to the first operating fluid, which second operating fluid flows inside the skirt along to a vertical longitudinal direction orthogonal to the development of the tubes of the primary tube bundle, and wherein the skirt has a prevalent development dimension (L) along the flow longitudinal direction of the second operating fluid; and nozzles for delivering the secondary operating fluid inside the skirt,
wherein an alternative configuration is provided using only the second operating fluid flooding the skirt by entering from a side inlet, without the presence of the above-mentioned nozzles, and an additional configuration using only the nozzles but not such side inlet.

Refrigeration apparatus R that includes a refrigerant circuit composed of compressor 11, gas cooler 28, electric expansion valve 39, and evaporator 41 includes: electric expansion valve 33; tank 36; split heat exchanger 29; electric expansion valve 43; electric expansion valve 47; auxiliary circuit 48; main circuit 38; low-pressure sensor 51; and control apparatus 57, in which control apparatus 57 regulates the pressure of the refrigerant after the refrigerant flows out of tank 36 but before flows into electric expansion valve 39 to be a first constant pressure when the pressure detected by low-pressure sensor 51 is smaller than a specified pressure, and regulates the pressure of the refrigerant to be a second constant pressure smaller than the first constant pressure when the pressure detected by low-pressure sensor 51 is larger than the specified pressure.

An air conditioner and a method for controlling the same include a compressor, a condenser, an evaporator, a receiver for storing at least one portion of a refrigerant passing through the condenser and a gas/liquid separator for filtering a liquid refrigerant of the refrigerant introduced from the receiver to supply a gaseous refrigerant into the compressor includes a first flow rate regulator for controlling the amount of refrigerant supplied into the receiver, a second flow rate regulator for controlling the amount of refrigerant introduced from the receiver into the gas/liquid separator, a first detection unit for detecting the amount of refrigerant stored in the receiver, and a control unit for controlling an opening degree of the first or second flow rate regulator, based on information of at least one of the amount of refrigerant detected by the first detection unit and the amount of refrigerant circulating in the air conditioner.

A flash tank overflow warning system for refrigeration systems and cold climate heat pumps. Some embodiments may include heat pump systems that have a compressor, a condenser, and a flash tank. A vapor injection line may be disposed between the flash tank and the compressor to direct vapor refrigerant from the flash tank to the compressor. A warning line may be coupled to a side surface of the flash tank and may be disposed between the flash tank and the vapor injection line. The vertical attachment position of the warning line on the side surface may determine a ratio of vapor to liquid refrigerant in the flash tank. The warning line may prevent overcharging during the active charging process by an operator (e.g., an HVAC technician, etc.). For example, once the warning system triggers, the operator would stop charging and may or may not release a little bit of refrigerant to achieve an ideally charged system.

A variable refrigerant charge refrigeration/air conditioner system is described that allows the refrigerant charge for the system to be altered based on operating or environmental factors. The system includes a main refrigerant loop holding a volume of refrigerant corresponding to a first level of refrigerant charge, a compressor in the main refrigerant loop, a condenser in the main refrigerant loop, and an evaporator in the main refrigerant loop. A branch refrigerant loop allows the alteration of the refrigerant charge using a control valve in the branch refrigerant loop and a receiver in the branch refrigerant loop. The receiver acts to hold a volume of refrigerant when the control valve is open, thereby removing the volume of refrigerant from the main refrigerant loop. A return path from the receiver to the main refrigerant loop allows refrigerant to flow back into the main loop from the receiver.