Refrigerant detection apparatus, computer readable medium, and refrigerant detection method

Abstract

When the subcooling degree is determined to be at zero kelvin, a calculation unit calculates a gas phase area ratio of the outdoor heat exchanger, using a first temperature difference which is a difference between an outdoor temperature and a condensation temperature of a refrigerant, a second temperature difference which is a difference between a refrigerant discharge temperature and the condensation temperature, an enthalpy difference of the refrigerant between an inlet and an outlet of the outdoor heat exchanger, and a specific heat at constant pressure gas of the refrigerant. The calculation unit compares the gas phase area ratio with a standard value set as a standard for the gas phase area ratio, and calculates a refrigerant amount in a refrigeration cycle apparatus, based on a comparison result.

1 . A refrigerant detection apparatus comprising:
 processing circuitry to determine whether a subcooling degree of a refrigerant is at zero kelvin in a refrigeration cycle apparatus including a compressor, a condenser, an expansion valve and an evaporator, the refrigerant circulating in the refrigeration cycle apparatus;   when the processing circuitry determines that the subcooling degree is at zero kelvin, to calculate a gas phase area ratio which is a gas phase volume rate of a total volume of the condenser, using a first temperature difference which is a difference between an outdoor temperature and a condensation temperature of the refrigerant, a second temperature difference which is a difference between a refrigerant discharge temperature of the compressor and the condensation temperature, an enthalpy difference of the refrigerant between an inlet of the condenser and an outlet of the condenser, and a specific heat at constant pressure gas of the refrigerant, to compare the calculated gas phase area ratio with a standard value set as a standard for the gas phase area ratio, and to calculate a refrigerant amount in the refrigeration cycle apparatus, based on a comparison result; and   to output a value obtained from the calculated refrigerant amount.   
     
     
         2 . The refrigerant detection apparatus according to  claim 1 , wherein
 the compressor, the condenser, the expansion valve, and the evaporator are disposed in the refrigeration cycle apparatus to form a refrigerant circuit in which the refrigerant circulates, and   the processing circuitry decides a correction coefficient that corrects the first temperature difference, based on a circulation amount of the refrigerant in the refrigerant circuit decided from a specification of the compressor and an operational state of the compressor, and based on a standard refrigerant circulation amount decided as a specification of the refrigerant circuit, and corrects the first temperature difference with the decided correction coefficient.   
     
     
         3 . The refrigerant detection apparatus according to  claim 2 , wherein
 the processing circuitry calculates the enthalpy difference of the refrigerant when the subcooling degree is at zero kelvin, based on an opening of the expansion valve, suction pressure of the compressor, discharge pressure of the compressor, and the circulation amount of the refrigerant.   
     
     
         4 . The refrigerant detection apparatus according to  claim 2 , wherein
 the processing circuitry calculates the subcooling degree of the refrigeration cycle apparatus, and determines whether or not the calculated subcooling degree is greater than zero kelvin,   the processing circuitry, when determining that the subcooling degree is greater than zero kelvin, calculates a liquid phase area ratio which is a liquid phase volume rate of a total volume of the condenser, using the calculated subcooling degree, the first temperature difference, the enthalpy difference of the refrigerant, a specific heat at constant pressure liquid of the refrigerant, and the correction coefficient, compares the calculated liquid phase area ratio with a standard value set as a standard for the liquid phase area ratio, and calculates a refrigerant amount in the refrigeration cycle apparatus, based on a comparison result, and   the processing circuitry outputs a value obtained from the calculated refrigerant amount using the liquid phase area ratio.   
     
     
         5 . The refrigerant detection apparatus according to  claim 1 , wherein
 the compressor, the condenser, the expansion valve, and the evaporator are disposed in the refrigeration cycle apparatus to form a refrigerant circuit in which the refrigerant circulates,   the refrigerant circuit includes a heat interchanger disposed between the condenser and the expansion valve, and a branch path that branches from a path between the heat interchanger and the expansion valve, passes through a second expansion valve which is different from a first expansion valve which is the expansion valve, passes through the heat interchanger, and connects to a path that connects the evaporator and the compressor, and   the processing circuitry calculates the enthalpy difference of the refrigerant when the subcooling degree is at zero kelvin, based on an opening of the first expansion valve, an opening of the second expansion valve, suction pressure of the compressor, discharge pressure of the compressor, a circulation amount of the refrigerant, and a temperature of a refrigerant that has flowed out of the heat interchanger in the branch path.   
     
     
         6 . A non-transitory computer readable medium storing a refrigerant detection program causing a computer to execute:
 a determination process to determine whether a subcooling degree of a refrigerant is at zero kelvin in a refrigeration cycle apparatus including a compressor, a condenser, an expansion valve and an evaporator, the refrigerant circulating in the refrigeration cycle apparatus;   a calculation process, when the determination process determines that the subcooling degree is at zero kelvin, to calculate a gas phase area ratio which is a gas phase volume rate of a total volume of the condenser, using a first temperature difference which is a difference between an outdoor temperature and a condensation temperature of the refrigerant, a second temperature difference which is a difference between a refrigerant discharge temperature of the compressor and the condensation temperature, an enthalpy difference of the refrigerant between an inlet of the condenser and an outlet of the condenser, and a specific heat at constant pressure gas of the refrigerant, to compare the calculated gas phase area ratio with a standard value set as a standard for the gas phase area ratio, and to calculate a refrigerant amount in the refrigeration cycle apparatus, based on a comparison result; and   an output process to output a value obtained from the refrigerant amount calculated by the calculation process.   
     
     
         7 . A refrigerant detection method comprising:
 determining whether a subcooling degree of a refrigerant is at zero kelvin in a refrigeration cycle apparatus including a compressor, a condenser, an expansion valve and an evaporator, the refrigerant circulating in the refrigeration cycle apparatus;   when determining that the subcooling degree is at zero kelvin, calculating a gas phase area ratio which is a gas phase volume rate of a total volume of the condenser, using a first temperature difference which is a difference between an outdoor temperature and a condensation temperature of the refrigerant, a second temperature difference which is a difference between a refrigerant discharge temperature of the compressor and the condensation temperature, an enthalpy difference of the refrigerant between an inlet of the condenser and an outlet of the condenser, and a specific heat at constant pressure gas of the refrigerant, comparing the calculated gas phase area ratio with a standard value set as a standard for the gas phase area ratio, and calculating a refrigerant amount in the refrigeration cycle apparatus, based on a comparison result; and   outputting a value obtained from the calculated refrigerant amount.