An air conditioner which continues driving with a deteriorated gas leakage sensor is provided. An air conditioner of the present invention includes an outdoor unit including a compressor and an indoor unit connected with the outdoor unit and uses flammable refrigerant. The air conditioner includes: a refrigerant gas sensor; and a controlling unit configured to stop the compressor at occurrence of abnormality, when the refrigerant gas sensor detects refrigerant gas while the compressor is being driven. After the compressor is stopped as the refrigerant gas sensor detects the refrigerant gas, the controlling unit does not start driving of the compressor until an operation to cancel the abnormality is performed.

A method for monitoring a refrigerant charge in a vapour compression system (1) is disclosed, the vapour compression system (1) including a compressor unit (2), a heat rejecting heat exchanger (3), a high pressure expansion device (4), a receiver (5), at least one expansion device (9, 10), and at least one evaporator (11, 12) arranged in a refrigerant path. A change in net mass flow into or out of the receiver (5) and/or a change in net enthalpy flow into or out of the receiver (5) is detected, and a pressure inside the receiver (5) is monitored as a function of time, following the detected change in net mass flow and/or in net enthalpy flow. A time constant being representative for dynamics of the receiver (5) is derived, based on the monitored pressure as a function of time, and information regarding a refrigerant charge in the vapour compression system (1) is derived, based on the derived time constant.

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<LFL×A×Ho.

A unit device of a refrigeration cycle apparatus forms part of a refrigerant circuit using flammable or slightly flammable refrigerant. The unit device includes a unit body and a storage box. The storage box is provided with a sensor that detects leakage of the refrigerant and a communicating portion that communicates with the unit body. The storage box is attached to an outer wall portion of the unit body.

A control device (3) for an air conditioning system (1) is provided with: an outdoor-unit control part (43) capable of communication with an outdoor unit (B) through a communication medium, the outdoor-unit control part (43) acquiring, through the communication medium, information about machinery installed in the outdoor unit (B) and outputting control commands to the machinery installed in the outdoor unit (B); and an indoor-unit control part (41) capable of communication with an indoor unit (A) through a communication medium, the indoor-unit control part (41) acquiring, through the communication medium, information about the machinery installed in the indoor unit (A) and outputting control commands to the machinery installed in the indoor unit (A). The control device (3) stores an operating state of the air conditioning system (1) for each load state of the air conditioning system (1) and determines the presence or absence of an anomaly in the machinery by comparing the present operating state and a past operating state associated with an equivalent load state. The control device (3) for the air conditioning system (1) can thereby ascertain the operating state of the air conditioning system (1) more simply and accurately.

Provided is an air conditioning apparatus that is capable of suppressing increases in volume and cost of the apparatus and performing more suitable overheating protection. An electric compressor is an inverter-integrated electric compressor integrally including a compressor, an electric motor that drives the compressor, and an inverter including a temperature sensor that detects the temperature in the vicinity of a semiconductor switching device, wherein a controller estimates a discharge temperature of the compressor on the basis of a correlation of respective pressure loading characteristics for the detected temperature of the inverter, for the rotational speed of the compressor, and for the motive force of the compressor in a refrigerating cycle.

A cooling device management system is connected to a cooling device that carries out refrigerant leakage detection mode to detect leaks of refrigerant. The cooling management system includes a transmission section that transmits instructions to the cooling device, a reception section that receives information from the cooling device, a refrigerant leakage detection schedule setting section that receives inputting of settings of a refrigerant leakage detection schedule in order to carry out the refrigerant leakage detection mode in the cooling device, a schedule executing section, and a display section. The schedule executing section transmits instructions to carry out the refrigerant leakage detection mode from the transmission section to the cooling device based on the refrigerant leakage detection schedule which is received using the refrigerant leakage detection schedule setting section. The display section outputs results of the refrigerant leakage detection mode based on the information received from the cooling device.

A refrigeration cycle apparatus includes a refrigeration cycle through which refrigerant is circulated, an indoor unit that accommodates at least a load-side heat exchanger of the refrigeration cycle and is placed indoors, and a controller that controls the indoor unit. The indoor unit includes an indoor air-blowing fan, an air inlet through which indoor air is sucked in, and an air outlet through which the air sucked in from the air inlet is blown indoors. The controller activates the indoor air-blowing fan when leakage of refrigerant is detected. An air passage that allows air to pass through the air outlet is established in the air outlet at least when leakage of refrigerant is detected.

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<LFL×A×Ho.

A system and method of retrofitting a heating, ventilation, air conditioning, and refrigeration system (HVACR) including one or more brazed, soldered, or mechanical connections between refrigerant lines is disclosed. The method includes removing a refrigerant from the HVACR system. The refrigerant that is removed is a non-flammable refrigerant. An enclosure is installed over the one or more brazed, soldered, or mechanical connections between refrigerant lines. A refrigerant is added to the HVACR system. The refrigerant being added has a global warming potential (GWP) that is relatively lower than the refrigerant removed from the HVACR system. The refrigerant being added has a relatively higher flammability than the refrigerant removed from the HVACR system.