A heat exchanger, connected to a refrigerant pipe, includes: heat transfer tubes; and a header that connects the refrigerant pipe and the heat transfer tubes, and that forms a refrigerant flow path between the refrigerant pipe and the heat transfer tubes. The header includes a first member that includes a first plate-shaped portion, and a second member that includes a second plate-shaped portion that is stacked on a heat transfer tubes side of the first plate-shaped portion. The first plate-shaped portion has a first opening that forms the refrigerant flow path. The second plate-shaped portion has a second opening that forms the refrigerant flow path. When viewed in a stacking direction of the first plate-shaped portion and the second plate-shaped portion, the second opening and the first opening overlap each other at a first region and at a second region that is different from the first region.

An air conditioner includes a refrigerant circuit, sensors that measure an amount representing a state of refrigerant in the refrigerant circuit, and a controller. The controller executes normal operation according to air conditioning load and a first detection operation of detecting refrigerant leakage. The controller adjusts a degree of subcooling at an outlet of the condenser to a first value during normal operation. The controller detects a value related to discharge temperature of the compressor or a value related to degree of superheating at an outlet of the evaporator, based on a sensor measurement result. The controller adjusts degree of subcooling to a second value larger than the first value when executing the first detection operation, and determines that refrigerant is leaking when the value related to discharge temperature of the compressor or the value related to degree of superheating is equal to or larger than a threshold value.

A refrigerant leakage notifying device includes a refrigerant sensor, a determination unit, a notification unit, and an output unit. The refrigerant sensor detects a refrigerant and outputs a detection signal according to a detection result. The determination unit receives the detection signal outputted from the refrigerant sensor and determines leakage of the refrigerant in accordance with the detection signal received. The notification unit notifies leakage of the refrigerant with at least one of sound and light in a case in which the determination unit has determined that the refrigerant is leaking. The output unit is provided separately from the refrigerant sensor. The output unit outputs a test signal to the determination unit. The test signal is a signal that the determination unit has determined that the refrigerant is leaking in a case in which the determination unit receives the signal.

An air conditioning system includes a control unit, a circulation system, an AC-to-DC conversion unit, and a fan module. The control unit detects an area temperature, controls the compressor unit being in operation or not in operation according to the area temperature and a setting temperature set by the control unit, and control a rotation speed of the condensing fan according to a temperature difference between the area temperature and the setting temperature. When the area temperature is greater than the setting temperature, the control unit controls the compressor unit being in operation and control the condensing fan being in full-speed operation.

When starting a cooling operation mode from a non-operating mode, the blower device of the indoor unit from which the start command is originated is operated. When starting a heating operation mode from a non-operating mode, the blower device of the indoor unit from which the start command is originated is operated after the heat medium temperature becomes equal to or greater than a preconfigured temperature.

An air conditioning apparatus suppresses an increase in power consumption associated with a reduction in start-stop frequency of a compressor. The air conditioning apparatus includes an outdoor unit equipped with a compressor and a plurality of indoor units connected with the outdoor unit and has a control device that performs thermo-off and thermo-on control such that a suction air temperature of the indoor unit falls within a predetermined temperature range with a set temperature defined as a reference. The control device detects the suction air temperatures of the indoor units, and, in a case where a sum total of air conditioning capacities of the indoor units, the suction air temperatures of which are between the set temperature and the thermo-off temperature, is at least a predetermined value, makes at least one indoor unit, the suction air temperatures of which are between the set temperature and the thermo-off temperature, forcedly thermo-off.

A sealed heat exchange system and air conditioner are provided herein. The sealed heat exchange system may include a compressor, a heat exchanger, a line filter, a variable electronic expansion device, a primary fluid path, and an alternate fluid path. The compressor may generally increase a pressure of a flowed refrigerant within the sealed heat exchange system. The heat exchanger may be in fluid communication with the compressor and the line filter may be in fluid communication with the heat exchanger. The primary fluid path may define a fluid inlet to receive the flowed refrigerant downstream of the heat exchanger and upstream of the expansion device. The alternate fluid path may define a fluid inlet to receive the flowed refrigerant downstream of the variable electronic expansion device and upstream of the heat exchanger.

An air-conditioning apparatus is configured to melt a large amount of adhering frost while maintaining an appropriate operation of a compressor by setting a defrosting operation time period depending on a low pressure of the compressor. The air-conditioning apparatus includes a refrigerant circuit including the compressor, a refrigerant flow switching device, a heat source-side heat exchanger, an expansion device, and a use-side heat exchanger, which are connected via a refrigerant pipe to form a refrigeration cycle, a pressure sensor configured to detect a pressure on a suction side of the compressor, and a controller configured to control, in a defrosting operation, the refrigerant flow switching device to supply compressed refrigerant from the compressor to the heat source-side heat exchanger, compare a value detected by the pressure sensor with a first threshold value, and change the defrosting operation time period based on a result of the comparison.

Provided is a refrigeration apparatus capable of reducing the leakage of a refrigerant even when a refrigerant leak occurs in a defrosting operation of a usage-side heat exchanger. When a refrigerant leak situation around a usage-side heat exchanger satisfies a predetermined leak condition in performing a defrosting operation with a connection state of a four-way switching valve brought into a defrosting connection state in which a heat source-side heat exchanger functions as an evaporator for a refrigerant and a usage-side heat exchanger functions as a radiator for the refrigerant, a controller performs density lowering control to lower a refrigerant density in the usage-side heat exchanger while maintaining the four-way switching valve at the defrosting connection state.

An air conditioning system provided which has: an outdoor device including at least a compressor and a first heat exchanger; an air handling device including an air supply fan and a second heat exchanger; an expansion valve; and a control section, wherein the compressor, the first heat exchanger, the expansion valve, and the second heat exchanger are sequentially connected in an annular shape to form a refrigerant circuit in which refrigerant circulates, and the control section adjusts a rotation speed of the air supply fan and/or a degree of opening of the expansion valve based on information including a temperature detection value of refrigerant on each of one end side and the other end side of the second heat exchanger, a temperature detection value of air toward the second heat exchanger, and a temperature detection value of air heat-exchanged by the second heat exchanger.