Leakage diagnosis apparatus, leakage diagnosis method, and refrigeration apparatus

A leakage diagnosis apparatus for diagnosing presence/absence of refrigerant leakage in a refrigerant circuit including a compressor, a radiator, a depressurization mechanism and an evaporator provided as circuit components thereof and performing a refrigeration cycle by circulating refrigerant therethrough, comprising:

• an index value calculator for calculating a leakage index value which changes in accordance with an amount of refrigerant leaking out of the refrigerant circuit based on an amount of refrigerant exergy loss in a circuit component;
• and
• a leakage determinator for determining whether there is refrigerant leakage in the refrigerant circuit based on the leakage index value calculated by the index value calculator,
• wherein an accumulator for separating liquid refrigerant from refrigerant sucked into the compressor is provided in the refrigerant circuit, and
• the leakage determinator does not determine that there is refrigerant leakage in the refrigerant circuit when a difference between a degree of superheat of the refrigerant flowing into the accumulator and a degree of superheat of the refrigerant flowing out of the accumulator is greater than or equal to a predetermined suction-side reference value even if it can be determined that there is refrigerant leakage in the refrigerant circuit based on the leakage index value.