Refrigeration apparatus

A refrigeration apparatus comprising:

• a refrigerant circuit including
• a compressor, a heat source-side heat exchanger, and a heat source-side expansion valve of a heat source unit,
• a usage-side heat exchanger of a usage unit, and
• a switching valve configured to switch between a normal connection state in which the heat source-side heat exchanger functions as a radiator for the refrigerant and the usage-side heat exchanger functions as an evaporator for the refrigerant and a defrosting connection state in which the heat source-side heat exchanger functions as an evaporator for the refrigerant and the usage-side heat exchanger functions as a radiator for the refrigerant;
• and
• a controller configured to switch the connection state of the switching valve to the defrosting connection state and to perform a defrosting operation when a predetermined defrosting condition is satisfied in the normal connection state of the switching valve,
• wherein
• the controller performs density lowering control to lower a refrigerant density in the usage-side heat exchanger while maintaining the switching valve at the defrosting connection state when a refrigerant leak situation around the usage-side heat exchanger satisfies a predetermined leak condition in the defrosting operation.