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

Abstract

A refrigerant leakage determination device includes a calculator and a determination unit. The calculator calculates a deviation degree of a refrigerant circuit from a normal state based on data related to operation of a refrigeration apparatus. The determination unit determines refrigerant leakage or estimates refrigerant leakage occurrence time based on a calculation result of the calculator. The calculator calculates first and second index values respectively from data related to operation of the refrigeration apparatus in a first period and a second period that differs in length from the first period and calculates the deviation degree of the refrigerant circuit from the normal state based on the first and second index values. The determination unit determines refrigerant leakage or estimates refrigerant leakage occurrence time based on the deviation degree of the refrigerant circuit from the normal state.

1 . 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.   
     
     
         2 . The refrigerant leakage determination device according to  claim 1 , wherein the calculator is configured to detect the deviation degree of the refrigerant circuit from the normal state based on a deviation degree between the first index value and the second index value. 
     
     
         3 . The refrigerant leakage determination device according to  claim 1 , wherein
 the data related to operation of the refrigeration apparatus in the first period include data for one day, and   the data related to operation of the refrigeration apparatus in the second period include data for ten days or more and thirty days or less.   
     
     
         4 . The refrigerant leakage determination device according to  claim 3 , wherein
 the data related to operation of the refrigeration apparatus in the first period include twenty-four data sets, and   the data related to operation of the refrigeration apparatus in the second period include two hundred and forty data sets or more and seven hundred and twenty data sets or less.   
     
     
         5 . The refrigerant leakage determination device according to  claim 1 , wherein
 the calculator is configured to calculate the first index value from a moving average of the data related to operation of the refrigeration apparatus in the first period, and   the calculator is configured to calculate the second index value from a moving average of the data related to operation of the refrigeration apparatus in the second period.   
     
     
         6 . The refrigerant leakage determination device according to  claim 1 , wherein each of the first index value and the second index value includes one of an estimated value of a discharge side refrigerant temperature of the compressor, an actual value of the discharge side refrigerant temperature of the compressor, or a discharge side refrigerant temperature index that is calculated based on the estimated value of the discharge side refrigerant temperature of the compressor and the actual value of the discharge side refrigerant temperature of the compressor. 
     
     
         7 . The refrigerant leakage determination device according to  claim 5 , wherein
 the calculator is configured to calculate an estimated value of a discharge side refrigerant temperature of the compressor for each power source frequency and power source voltage of a power source, which is a source of power supplied to the refrigeration apparatus, using a regression analysis, wherein a variable for the regression analysis is at least one of a condensation temperature, an evaporation temperature, an opening degree of an expansion valve that is the decompression device, an operating frequency of the compressor, or a rotational speed of the compressor when an amount of refrigerant contained in the refrigerant circuit is in an appropriate range.   
     
     
         8 . The refrigerant leakage determination device according to  claim 1 , wherein the calculator is configured to calculate the first index value and the second index value from data excluding at least one of data in a section in which the refrigeration apparatus is stopped, data in a section immediately after activation of the compressor, data in a section immediately after deactivation of the compressor, or data in a section immediately after operation of the compressor is switched. 
     
     
         9 . The refrigerant leakage determination device according to  claim 1 , wherein the calculator is configured to calculate the first index value and the second index value using alternative data to at least one of data in a section in which the refrigeration apparatus is stopped, data in a section immediately after activation of the compressor, data in a section immediately after deactivation of the compressor, or data in a section immediately after operation of the compressor is switched. 
     
     
         10 . The refrigerant leakage determination device according to  claim 9 , wherein the alternative data is a predetermined representative value or a value before or after the section that uses the alternative data among the section in which the refrigeration apparatus is stopped, the section immediately after activation of the compressor, the section immediately after deactivation of the compressor, or the section immediately after operation of the compressor is switched. 
     
     
         11 . The refrigerant leakage determination device according to  claim 1 , wherein the calculator is configured to calculate a deviation degree between the first index value and the second index value based on at least one of a standard deviation, skewness, likelihood, kurtosis, or an average that is obtained using the first index value and the second index value. 
     
     
         12 . The refrigerant leakage determination device according to  claim 1 , wherein
 the refrigeration apparatus further includes a notification unit that issues a notification of a determination result of whether the refrigerant has leaked or a notification of an estimation result of the refrigerant leakage occurrence time, and   the notification unit is configured to issue a notification of a determination result of whether the refrigerant has leaked or a notification of an estimation result of the refrigerant leakage occurrence time at least one of when there is a user request, when the refrigeration apparatus or the refrigerant leakage determination device is powered on, or when a pre-trip inspection of the refrigeration apparatus is conducted.   
     
     
         13 . A refrigeration apparatus, comprising:
 the refrigerant leakage determination device according to  claim 1 .   
     
     
         14 . The refrigeration apparatus according to  claim 13 , wherein
 the refrigeration apparatus is a transporting refrigeration apparatus,   the transporting refrigeration apparatus further includes a notification unit configured to issue a notification of a determination result of whether the refrigerant has leaked or a notification of an estimation result of the refrigerant leakage occurrence time, and   the notification unit is configured to issue a notification of a determination result of whether the refrigerant has leaked or a notification of an estimation result of the refrigerant leakage occurrence time at least one of when there is a user request, when the transporting refrigeration apparatus or the refrigerant leakage determination device is powered on, when transportation of the transporting refrigeration apparatus is completed, or when a pre-trip inspection of the transporting refrigeration apparatus is conducted.   
     
     
         15 . A method for determining a refrigerant leakage of a refrigeration apparatus, the refrigeration apparatus including a refrigerant circuit, and 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 method comprising:
 storing data related to operation of the refrigeration apparatus;   calculating a first index value from data related to operation of the refrigeration apparatus in a first period and calculating a second index value from data related to operation of the refrigeration apparatus in a second period that differs in length from the first period;   calculating a deviation degree of the refrigerant circuit from a normal state based on the first index value and the second index value; and   determining whether the refrigerant has leaked or estimating a refrigerant leakage occurrence time based on the deviation degree of the refrigerant circuit from the normal state.   
     
     
         16 . The refrigerant leakage determination device according to  claim 2 , wherein
 the data related to operation of the refrigeration apparatus in the first period include data for one day, and   the data related to operation of the refrigeration apparatus in the second period include data for ten days or more and thirty days or less.   
     
     
         17 . The refrigerant leakage determination device according to  claim 2 , wherein
 the calculator is configured to calculate the first index value from a moving average of the data related to operation of the refrigeration apparatus in the first period, and   the calculator is configured to calculate the second index value from a moving average of the data related to operation of the refrigeration apparatus in the second period.   
     
     
         18 . The refrigerant leakage determination device according to  claim 3 , wherein
 the calculator is configured to calculate the first index value from a moving average of the data related to operation of the refrigeration apparatus in the first period, and   the calculator is configured to calculate the second index value from a moving average of the data related to operation of the refrigeration apparatus in the second period.   
     
     
         19 . The refrigerant leakage determination device according to  claim 4 , wherein
 the calculator is configured to calculate the first index value from a moving average of the data related to operation of the refrigeration apparatus in the first period, and   the calculator is configured to calculate the second index value from a moving average of the data related to operation of the refrigeration apparatus in the second period.   
     
     
         20 . The refrigerant leakage determination device according to  claim 2 , wherein each of the first index value and the second index value includes one of an estimated value of a discharge side refrigerant temperature of the compressor, an actual value of the discharge side refrigerant temperature of the compressor, or a discharge side refrigerant temperature index that is calculated based on the estimated value of the discharge side refrigerant temperature of the compressor and the actual value of the discharge side refrigerant temperature of the compressor.