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.

The present disclosure relates to a novel vapor compression refrigeration system, and the methods of making and using the vapor compression refrigeration system.

The present disclosure relates to a novel vapor compression refrigeration system, and the methods of making and using the vapor compression refrigeration system.

An illustrative example refrigerant system includes a compressor configured to pressurize a refrigerant fluid. The compressor includes a sump portion. A heater is situated to heat at least the sump portion. A controller is configured to selectively operate the heater to apply heat to at least the sump portion while the compressor is off to establish and maintain a superheat condition in the compressor.

An illustrative example refrigerant system includes a compressor configured to pressurize a refrigerant fluid. The compressor includes a sump portion. A heater is situated to heat at least the sump portion. A controller is configured to selectively operate the heater to apply heat to at least the sump portion while the compressor is off to establish and maintain a superheat condition in the compressor.

An air-conditioning apparatus includes a control unit performing liquid refrigerant equalization control for correcting an imbalance in liquid refrigerant amount between accumulators. The control unit includes a first liquid refrigerant equalization control unit controlling an output of a fan to perform the liquid refrigerant equalization control and a second liquid refrigerant equalization control unit controlling a frequency of a compressor to perform the liquid refrigerant equalization control. The second liquid refrigerant equalization control unit determines an increase or reduction in frequency of the compressor so that a total refrigerant circulation amount is not below a predetermined amount. When a value is within a predefined acceptable range, the control unit selects the first liquid refrigerant equalization control unit to perform the liquid refrigerant equalization control. When the value is outside the acceptable range, the control unit selects the second liquid refrigerant equalization control unit to perform the liquid refrigerant equalization control.

A device for use in a refrigeration or heat pump system. A device includes an outer casing which includes a longitudinal cylindrical shell and end plates arranged at both ends of the shell, and at least three units of the refrigeration or heat pump system arranged inside the same common outer casing, which units are selected from the group consisting of an evaporator, a superheater, an economizer, a condenser, a desuperheater, a sub-cooler and an oil cooler.

A device for use in a refrigeration or heat pump system. A device includes an outer casing which includes a longitudinal cylindrical shell and end plates arranged at both ends of the shell, and at least three units of the refrigeration or heat pump system arranged inside the same common outer casing, which units are selected from the group consisting of an evaporator, a superheater, an economizer, a condenser, a desuperheater, a sub-cooler and an oil cooler.

A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

Disclosed herein is a refrigeration cycle includes a first refrigerant circuit configured to cause a refrigerant ejected from a compressor to flow through a condenser, an ejector, a first evaporator, and a second evaporator and flow back to the compressor; a second refrigerant circuit configured to cause the refrigerant to bypass the first evaporator in the first refrigerant circuit; and a third refrigerant circuit branching at a junction provided at a downstream end of the condenser from at least one of the first refrigerant circuit and the second refrigerant circuit, and configured to cause the refrigerant to flow through an expansion device and a third evaporator and flow to the ejector. By such configuration, a coefficient of performance (COP) of a refrigeration cycle may be improved and an ejector may be used to improve energy efficiency.