A linear compressor includes a linear motor including a mover that reciprocates with respect to a stator; a compression unit configured to define a compression space in a cylinder while a piston connected to the mover reciprocates in the cylinder; a frame disposed outside of the cylinder; a plurality of discharge covers that define discharge spaces sequentially receiving refrigerant discharged from the compression space; and a gas bearing configured to guide part of refrigerant accommodated in a discharge any one of the plurality of discharge covers to lubricate between the cylinder and the piston with the refrigerant. The discharge cover structure is configured to restrict heat transfer between the discharge covers and the frame.

A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes a refrigerant loop having a compressor configured to circulate a refrigerant therethrough, a motor configured to drive rotation of the compressor, wherein the motor is a permanent magnet assisted synchronous reluctance (PMASR) motor, and a motor cooling system configured to direct a portion of the refrigerant from the refrigerant loop and through a housing of the PMASR motor to place the portion of the refrigerant in thermal communication with components of the PMASR motor.

Air recirculation systems for heat pumps are disclosed. The air recirculation systems include a heat pump subsystem and a recirculation subsystem. The recirculation subsystem can include one or more arms that direct cool, dehumidified air flowing from the heat pump subsystems back to air inlets. The recirculation subsystems can transition from open to closed configurations either manually or via motors. The air recirculation systems can include a controller that outputs a control signal to the motors to open or close the recirculation subsystems. The control signals can be based on temperature data, current data, and the like.

A refrigeration apparatus includes a refrigerant circuit including: a compressor, a radiator, an expansion mechanism, and an evaporator. The refrigerant circuit encloses a refrigerant that contains a fluorinated hydrocarbon that causes a disproportionation reaction. The refrigerant circuit further includes: a discharged refrigerant recovery receiver that is connected to a path between a discharge side of the compressor and a gas side of the radiator through a discharged refrigerant branch pipe; and a discharged refrigerant relief mechanism that is disposed in the discharged refrigerant branch pipe and that connects the discharge side of the compressor with the discharged refrigerant recovery receiver when the refrigerant on the discharge side of the compressor satisfies a predetermined condition. The predetermined condition includes at least one of a first condition under which the refrigerant does not yet cause the disproportionation reaction and a second condition under which the refrigerant causes the disproportionation reaction.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

A combined heat exchanger, a heat exchange system, and an optimization method thereof are provided. The heat exchange system includes: an enhanced vapor injection compressor, a condenser, an expansion valve and an evaporator, which are located in a main circuit; wherein the heat exchange system further includes a first branch branched from the main circuit to an vapor injection port of the compressor at a branch point P downstream of the condenser, and a first heat exchange unit and a second heat exchange unit are further provided in the main circuit between the branch point P and the expansion valve; and wherein a refrigerant leaving the condenser is divided at the branch point P into a first portion passing through the first heat exchange unit and the second heat exchange unit from the main circuit, and a second portion passing through the first branch to the vapor injection port.

A method for controlling a refrigerator includes turning on a compressor to operate with a predetermined cooling power for cooling a storage compartment, turning off the compressor when a temperature of the storage compartment reaches a temperature equal to or lower than a first reference temperature, and turning on the compressor again when the temperature of the storage compartment reaches a temperature equal to or higher than a second reference temperature higher than the first reference temperature. In the turning on the compressor again, the compressor is operated with a cooling power determined based on an on slope, which is a temperature change slope of the storage compartment during an on time of the compressor, and an off slope, which is a temperature change slope of the storage compartment during an off time of the compressor.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

Air recirculation systems for heat pumps are disclosed. The air recirculation systems include a heat pump subsystem and a recirculation subsystem. The recirculation subsystem can include one or more arms that direct cool, dehumidified air flowing from the heat pump subsystems back to air inlets. The recirculation subsystems can transition from open to closed configurations either manually or via motors. The air recirculation systems can include a controller that outputs a control signal to the motors to open or close the recirculation subsystems. The control signals can be based on temperature data, current data, and the like.

A vehicle air-conditioning apparatus heat pump system configured so that an excessive increase in the temperature (superheat degree) of refrigerant discharged from a compressor can be prevented in air-heating operation. The heat pump system (HP) includes a compressor (C) and an indoor heat exchanger (HXC2) on a refrigerant circuit (RC). A first branched flow path (BC1) on which a first expansion mechanism (EX1) with an adjustable opening degree and a first heat absorption heat exchanger (HXA1) are arranged in series and a second branched flow path (BC2) on which a second expansion mechanism (EX2) with an adjustable opening degree and a second heat absorption heat exchanger (HXA2) are arranged in series, where the first branched flow path (BC1) and the second branched flow path (BC2) are arranged in parallel on the refrigerant circuit extending from the indoor heat exchanger to the compressor.