Refrigerant leakage determination device, freezing device including this refrigerant leakage determination device, and refrigerant leakage determination method

A refrigerant leakage determination device that determines a refrigerant leakage of a refrigeration apparatus, the refrigeration apparatus including a refrigerant circuit, the refrigerant circuit including a compressor, a condenser, a decompression device, and an evaporator and being configured so that a refrigerant circulates through the compressor, the condenser, the decompression device, and the evaporator, the refrigerant leakage determination device comprising:

• a calculator that calculates a deviation degree of the refrigerant circuit from a normal state based on data related to operation of the refrigeration apparatus;
• and
• a determination unit that determines whether the refrigerant has leaked or estimates a refrigerant leakage occurrence time based on a calculation result of the calculator, wherein
• the data related to operation of the refrigeration apparatus include data related to operation of the refrigeration apparatus in a first period and data related to operation of the refrigeration apparatus in a second period that differs in length from the first period,
• the calculator is configured to calculate a first index value from the data related to operation of the refrigeration apparatus in the first period and calculate a second index value from the data related to operation of the refrigeration apparatus in the second period,
• the calculator is configured to calculate the deviation degree of the refrigerant circuit from the normal state based on the first index value and the second index value, and
• the determination unit is configured to determine whether the refrigerant has leaked or estimate the refrigerant leakage occurrence time based on the deviation degree of the refrigerant circuit from the normal state.