An indoor unit includes an air-sending fan, an air inlet through which air of an indoor space is sucked in, and an air outlet located above the air inlet and through which the air sucked in through the air inlet is blown out to the indoor space. A control unit activates the air-sending fan when leakage of the refrigerant is detected. When M [kg] represents an amount of charge of the refrigerant in a refrigeration cycle, LFL [kg/m.sup.3] represents a lower flammable limit of the refrigerant, A [m.sup.2] represents a floor area of the indoor space, and Ho [m] represents a height of the air outlet above a floor surface of the indoor space, the amount of charge M, the lower flammable limit LFL, the floor area A, and the height Ho satisfy a relationship of M<LFLAHo.

A system includes an air conditioning device with a heat exchanger that sends conditioned air to an air conditioned space, a ventilation device that ventilates the air conditioned space, a refrigerant sensor that detects a concentration of a refrigerant in the air conditioned space, and a control unit that controls operations of the air conditioning device and ventilation device. On determination that the refrigerant concentration acquired from the refrigerant sensor exceeds a first predetermined value, the control unit sets an operation of a compressor of the air conditioning device to a stop state and sets the ventilation device to an operating state. On determination that the refrigerant concentration that has exceeded the first predetermined value becomes equal to or less than the first predetermined value, the control unit continues the stop state of the compressor and operating state of the ventilation device until a predetermined timing.

A system includes a compressor, an indoor fan, a thermostat, an indoor fan controller, and a compressor controller. The thermostat provides first and second signals based on indoor loading. The fan controller operates the fan in low speed mode and the compressor controller operates the compressor in low capacity mode when only the first signal is asserted. The compressor controller automatically switches the compressor to high capacity mode if only the first signal remains asserted past the low capacity mode runtime. The fan controller operates the fan in high speed mode when the second signal is asserted while the first signal is still asserted. The compressor controller continues to operate the compressor in high capacity mode and the fan controller operates the fan in low speed mode after the second signal is de-asserted, until the first signal is de-asserted, at which point the fan and compressor are turned off.

A refrigeration cycle apparatus includes a gas leakage sensor and a control device. When refrigerant leakage is detected by the gas leakage sensor, the control device performs a first mode operation to operate a compressor in such a state that a four-way valve is set to a cooling operation state, an expansion valve is opened, and a first shutoff valve is closed. After performing the first mode operation, the control device performs a second mode operation to operate the compressor in such a state that the four-way valve is set to a heating operation state and the first shutoff valve is closed.

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.

A performance degradation diagnosis system includes a determining unit, and control unit. A refrigeration cycle apparatus includes a refrigerant circuit having a compressor, heat-source-side heat exchanger, and use-side heat exchanger. The determining unit determines, based on an index indicating an operation state of the refrigeration cycle apparatus, performance degradation of the refrigeration cycle apparatus with respect to each of a plurality of performance degradation factors. In a case in which the determining unit determines performance degradation, the control unit grasps an operation condition of the refrigeration cycle apparatus which is operating. In a case in which the operation condition of the refrigeration cycle apparatus is not suitable to determine performance degradation with respect to a performance degradation factor of a determination target, the control unit controls the operation condition of the refrigeration cycle apparatus so that the operation condition of the refrigeration cycle apparatus becomes an appropriate operation condition.

According to an embodiment, a refrigeration system that cools a compartment includes a compressor, a condenser, a condenser fan, a condenser fan motor, an evaporator, an evaporator fan, an evaporator fan motor, and tubing adapted to transport refrigerant through the refrigeration system in a circulation order from the compressor to the condenser to the evaporator and back to the compressor again. The evaporator fan may be positioned in an air inlet path to the evaporator. The evaporator fan motor may be outside a chilled air circuit of the evaporator.

A usage-side air-conditioning apparatus has: a casing; a usage-side heat exchanger to cool or heat air inside the casing through the use of a refrigerant supplied from a heat-source-side air-conditioning apparatus; an air supply/exhaust mechanism to take room air and/or outdoor air in from an air-conditioned space or outside of the air-conditioned space, supply the air as supply air to the air-conditioned space, and exhaust the air as exhaust air out of the air-conditioned space; and a refrigerant leakage detection device to detect the refrigerant. When the refrigerant leakage detection device has detected the refrigerant, a refrigerant exhaust operation is performed by the air supply/exhaust mechanism to exhaust the refrigerant out of the air-conditioned space along with the air inside the casing.

Provided is an air-conditioner which performs an appropriate control in the event of a leak of refrigerant. The air-conditioner (100) is provided with: a refrigerant circuit (10); a refrigerant leak sensor (25) which senses a leak of refrigerant in the refrigerant circuit (10); an indoor fan (Fi) which delivers air to the indoor heat exchanger (15); and an indoor control circuit 32 which, upon sensing a leak of refrigerant by the refrigerant leak sensor (25), controls the indoor fan (Fi) based on whether the refrigerant sealed in the refrigerant circuit 10 is flammable.

A heat pump includes a compressor, a metering device, a first heat exchanger, a second heat exchanger, a first fan, a second fan, and a refrigerant circuit between the first heat exchanger and the second heat exchanger. A thermal storage device coupled to the refrigerant circuit is configured to store thermal energy when the refrigerant fluid is above a threshold temperature and discharge thermal energy when the refrigerant fluid is below the threshold temperature. The heat pump is operated in a heating mode in which heat is transferred from the refrigerant fluid at the first heat exchanger and the temperature of the refrigerant fluid at the thermal storage device is above the threshold temperature, and a defrost mode in which heat is transferred to the refrigerant fluid at the first heat exchanger and the temperature of the refrigerant fluid at the thermal storage device is below the threshold temperature.