Patent ID: 7987679

Claim:
An air conditioning apparatus comprising: a refrigerating cycle to connect a compressor, a high-pressure-side heat exchanger, a throttle device and a low-pressure-side heat exchanger by piping, to circulate a refrigerant of high temperature and high pressure in the high-pressure-side heat exchanger, and to circulate a refrigerant of low temperature and low pressure in the low-pressure-side heat exchanger; a temperature detection part of high-pressure refrigerant to detect a temperature of the refrigerant in the high-pressure-side heat exchanger; a temperature detection part of high-pressure-side heat exchanger entrance-side refrigerant to detect a temperature of the refrigerant at an entrance side of the high-pressure-side heat exchanger; a temperature detection part of high-pressure-side heat exchanger exit-side refrigerant to detect a temperature of the refrigerant at an exit side of the high-pressure-side heat exchanger; a fluid temperature detection part to detect a temperature at a location of the fluid circulating outside of the high-pressure-side heat exchanger; a calculation comparison part to calculate a first value obtained by dividing a supercooling degree SC which is obtained by subtracting the temperature detected by the temperature detection part of high-pressure-side heat exchanger exit-side refrigerant from the temperature detected by the temperature detection part of high-pressure refrigerant, by dT c which is a value obtained by subtracting the temperature detected by the fluid temperature detection part from the temperature detected by the temperature detection part of high-pressure refrigerant, and 1−EXP(−NTU R ) as a second value based on NTU R which is obtained by calculating (ΔH CON ×A L )/(dT c ×C pr ×A) (where ΔH CON is an enthalpy difference between an enthalpy at the entrance of the high-pressure-side heat exchanger which is calculated from the temperature detected by the temperature detection part of high-pressure-side heat exchanger entrance-side refrigerant and the temperature detected by the temperature detection part of high-pressure refrigerant and an enthalpy at the exit of the high-pressure-side heat exchanger which is calculated from the temperature detected by the temperature detection part of high-pressure-side heat exchanger exit-side refrigerant and the temperature detected by the temperature detection part of high-pressure refrigerant, A L is a heating surface area of liquid phase of the high-temperature-side heat exchanger, A is a heating surface area of the high-temperature-side heat exchanger, and C pr is a specific heat at constant pressure of the refrigerant), and compare the first value calculated and the second value calculated; and a judgment part to judge a refrigerant leak based on a comparison result of the calculation comparison part.