An air conditioner comprises: a refrigerant circuit configured to circulate refrigerant through a compressor, a condenser, an LEV and an evaporator; a first temperature sensor configured to sense the temperature of liquid refrigerant at the inlet port of the evaporator; and a controller configured to control the compressor and the LEV. In a case where a temperature sensed by the first temperature sensor is lower than a frosting reference temperature, the controller increases the opening degree of the LEV and also increases the operating frequency of the compressor as compared with a case where the temperature sensed by the first temperature sensor is higher than the frosting reference temperature.

A heating, ventilation, and air conditioning (“HVAC”) system includes an evaporator coil and a compressor fluidly coupled to the evaporator coil via a suction line. A condenser coil is fluidly coupled to the compressor via a discharge line and fluidly coupled to a metering device via a liquid line. A charge compensator is fluidly coupled to the liquid line via a connection line. A charge compensator re-heat valve is disposed in the connection line.

A refrigeration system includes a compressor for compressing a gaseous refrigerant, such that the temperature and pressure thereof increases, whereas the boiling point thereof decreases; a condenser, in which the gaseous refrigerant from the compressor exchanges heat with a high temperature heat carrier, said heat exchange resulting in the refrigerant condensing; an expansion valve reducing the pressure of liquid refrigerant from the condenser, hence reducing the boiling point of the refrigerant; an evaporator, in which the low boiling point refrigerant exchanges heat with a low temperature heat carrier, such that the refrigerant vaporizes; and a suction gas heat exchanger exchanging heat between high temperature liquid refrigerant from the condenser and low temperature gaseous refrigerant from the evaporator. The low temperature gaseous refrigerant entering the suction gas heat exchanger contains a certain amount of low temperature liquid refrigerant, said low temperature liquid refrigerant vaporizing as a result of the heat exchange with the high temperature liquid refrigerant from the condenser. Disclosed is also a refrigeration method.

An apparatus includes a compressor, a first heat exchanger, a reheater, a first valve, a second heat exchanger, and a blower. The compressor compresses a refrigerant. The blower moves air proximate the second heat exchanger to the reheater. During a first mode of operation: the first heat exchanger removes heat from a first portion of the refrigerant from the compressor, the first valve opens such that a second portion of the refrigerant from the compressor flows to the reheater, the second heat exchanger uses the first portion of the refrigerant from the first heat exchanger and the second portion of the refrigerant from the reheater to cool air proximate the second heat exchanger, and the reheater uses the second portion of the refrigerant from the compressor to heat the air moved by the blower.

Refrigerant is caused to be in a superheating state without impairing the performance of a cascade heat exchanger. A refrigerant cycle system includes a first refrigerant circuit, a second refrigerant circuit, and a first cascade heat exchanger. The first cascade heat exchanger exchanges heat between a first refrigerant that flows in the first refrigerant circuit and a second refrigerant that flows in the second refrigerant circuit. The refrigerant cycle system includes a switching mechanism. The switching mechanism switches a flow path of a refrigerant of at least either one of the first refrigerant circuit and the second refrigerant circuit. The first cascade heat exchanger includes a first main heat exchanging unit acid a first sub heat exchanging unit. The first sub heat exchanging unit is configured to cause the first refrigerant that has passed through the first main heat exchanging unit to be in a superheating state.

A refrigeration system includes a heat exchanger configured to provide superheat control for the low temperature low pressure gas refrigerant flowing out of the evaporator and through the first side of the heat exchanger by transferring heat from the high pressure high temperature superheated gas refrigerant flowing through a second side of the heat exchanger. A modulating solenoid valve is located at the inlet of the second side of the heat exchanger and configured to modulate the flow of high pressure high temperature superheated gas refrigerant flowing through the second side of the heat exchanger. A temperature sensor is located in such a way as to measure the temperature of the gas refrigerant flowing out of the evaporator and through the first side of the heat exchanger. A controller is configured to calculate the superheat of the gas refrigerant based on the measured temperature and measured pressure of the gas refrigerant and may compare the calculated superheat to a superheat threshold. If the calculated superheat is less than the superheat threshold, the controller will modulate the flow the high pressure high temperature gas refrigerant flowing through the second side of the heat exchanger. The refrigeration system may be activated in a variety of methods by appropriate control of the valves and other system components.

In a refrigeration cycle apparatus according to the present disclosure, the circulation direction of refrigerant is switched between a first circulation direction and a second circulation direction opposite to the first circulation direction. The first circulation direction is a circulation direction in order of a compressor, a first heat exchanger, a first expansion valve, a third heat exchanger, a fourth heat exchanger, a second expansion valve, and a second heat exchanger. When a circulation direction of the refrigerant is the first circulation direction, the refrigerant from the third heat exchanger exchanges heat with the refrigerant from the second heat exchanger in the fourth heat exchanger. When a circulation direction of the refrigerant is the second circulation direction, the refrigerant from the fourth heat exchanger exchanges heat with the refrigerant from the first heat exchanger in the third heat exchanger.

A refrigeration system includes a heat exchanger configured to provide superheat control for the low temperature low pressure gas refrigerant flowing out of the evaporator and through the first side of the heat exchanger by transferring heat from the high pressure high temperature superheated gas refrigerant flowing through a second side of the heat exchanger. A modulating solenoid valve is located at the inlet of the second side of the heat exchanger and configured to modulate the flow of high pressure high temperature superheated gas refrigerant flowing through the second side of the heat exchanger. A temperature sensor is located in such a way as to measure the temperature of the gas refrigerant flowing out of the evaporator and through the first side of the heat exchanger. A controller is configured to calculate the superheat of the gas refrigerant based on the measured temperature and measured pressure of the gas refrigerant and may compare the calculated superheat to a superheat threshold. If the calculated superheat is less than the superheat threshold, the controller will modulate the flow the high pressure high temperature gas refrigerant flowing through the second side of the heat exchanger. The refrigeration system may be activated in a variety of methods by appropriate control of the valves and other system components.

A refrigeration system includes a compressor for compressing a gaseous refrigerant, such that the temperature and pressure thereof increases; a four-way valve controlling whether the refrigeration system is in a heating mode or a cooling mode; a condenser, in which the gaseous refrigerant from the compressor exchanges heat with a high temperature heat carrier, said heat exchange resulting in the refrigerant condensing; an expansion valve reducing the pressure of liquid refrigerant from the condenser, hence reducing the boiling point of the refrigerant; an evaporator, in which the low boiling point refrigerant exchanges heat with a low temperature heat carrier, such that the refrigerant vaporizes; and a suction gas heat exchanger exchanging heat between high temperature liquid refrigerant from the condenser and low temperature gaseous refrigerant from the evaporator. A balance valve is arranged for controlling the amount of heat exchange between the high temperature liquid refrigerant and the low temperature gaseous refrigerant in the suction gas heat exchanger by directing a flow of high temperature liquid refrigerant directly from the condenser to the expansion valve. Disclosed is also a method for controlling such a system.

An apparatus includes a compressor, a first heat exchanger, a reheater, a first valve, a second heat exchanger, a four-way valve, a cap tube, and a blower. The compressor compresses a refrigerant. The blower moves air proximate the second heat exchanger to the reheater. During a heating mode of operation, the four-way valve is configured to direct refrigerant from the compressor to the second heat exchanger; the second heat exchanger is configured to use the refrigerant from the compressor to heat air proximate the second heat exchanger; and the cap tube is configured to allow refrigerant to bypass the reheater.