Air-conditioning apparatus with leak detection control

An air-conditioning apparatus comprising:

• a refrigeration circuit in which a compressor, a flow switching device, a heat-source-side heat exchanger, an expansion device, a use-side heat exchanger, and an accumulator are connected by pipes, the compressor being configured to compress refrigerant and discharge the compressed refrigerant, the flow switching device being provided on a discharge side of the compressor and configured to change a flow passage of the refrigerant in a switching manner, the expansion device being configured to reduce a pressure of the refrigerant, the use-side heat exchanger being configured to condition air in an indoor space, the accumulator being provided on a suction side of the compressor and configured to store liquid refrigerant;
• a first shut-off device provided at a pipe that connects the heat-source-side heat exchanger and the expansion device;
• a refrigerant leak detection device configured to detect a leak of refrigerant into the indoor space;
• and
• a controller configured to control the compressor, the flow switching device, and the first shut-off device, and to cause a leak-amount reduction operation to be performed when the refrigerant leak detection device detects the leak of refrigerant,
• wherein the controller is configured to control the flow switching device to switch a connection state set by the flow switching device between a first connection state and a second connection state, the first connection state being a connection state in which the discharge side of the compressor is connected to the heat-source-side heat exchanger and the suction side of the compressor is connected to the use-side heat exchanger via the accumulator, the second connection state being a connection state in which the discharge side of the compressor is connected to the use-side heat exchanger and the suction side of the compressor is connected to the heat-source-side heat exchanger via the accumulator, and
• wherein at time of performing the leak-amount reduction operation, the controller determines whether the heat-source-side heat exchanger has space to store refrigerant or not,
• when determining that the heat-source-side heat exchanger has the space, the controller exerts control to perform a refrigerant retrieval operation in which the first shut-off device is closed, the flow switching device is caused to switch the connection state to the first connection state, the compressor is driven, and refrigerant in the use-side heat exchanger is retrieved therefrom into a storage unit including the accumulator and the heat-source-side heat exchanger,
• when determining the heat-source-side heat exchanger does not have the space, the controller exerts control to perform a refrigerant transfer operation in which the flow switching device is caused to switch the connection state to the second connection state, the compressor is stopped, and refrigerant condensed at the heat-source-side heat exchanger is transferred to the accumulator through the flow switching device, and
• wherein at the time of performing the leak-amount reduction operation, the controller determines whether refrigerant on an indoor side is completely retrieved or not,
• when determining that the refrigerant on the indoor side is completely retrieved, the controller exerts control to perform an outflow prevention operation in which the retrieved refrigerant is shut up in the heat-source-side heat exchanger and the accumulator, and
• when determining that the refrigerant on the indoor side is not completely retrieved, the controller exerts control to repeatedly perform the refrigerant retrieval operation and the refrigerant transfer operation to continuously retrieve refrigerant.