Refrigerant leakage determination method and refrigeration cycle apparatus

Abstract

A refrigerant leakage determination method includes the following steps. A refrigerant circuit formed by connecting a heat source unit and a utilization unit by a connection pipe is filled with a refrigerant of a first filling amount smaller than a target filling amount. Then, a first trial operation of circulating the refrigerant of the first filling amount in the refrigerant circuit is performed, and first trial operation data is acquired. Then, after the step of acquiring, the refrigerant circuit is filled with the refrigerant until the target filling amount is reached. Thereafter, normal operation data is acquired during a normal operation after filling the refrigerant circuit with the target filling amount. Subsequently, the presence or absence of a refrigerant leakage from the refrigerant circuit is determined on the basis of the normal operation data and the first trial operation data.

1 . A refrigerant leakage determination method, comprising:
 providing a refrigerant circuit that includes a heat source connected to a heat utilizer by a connection pipe;   filling the refrigerant circuit with a refrigerant to a first filling amount that is smaller than a target filling amount;   acquiring first trial operation data by performing a first trial operation of circulating the first filling amount of the refrigerant in the refrigerant circuit;   filling the refrigerant circuit with the refrigerant to the target filling amount after acquiring the first trial operation data;   acquiring normal operation data during a normal operation after filling the refrigerant circuit to the target filling amount; and   determining presence or absence of a refrigerant leak from the refrigerant circuit by comparing the normal operation data and the first trial operation data.   
     
     
         2 . The refrigerant leakage determination method according to  claim 1 , wherein the normal operation data and the first trial operation data include data of an opening degree of an expansion valve of the heat utilizer, a degree of superheating at an outlet of an evaporator of the heat source or the heat utilizer, a degree of subcooling at an outlet of a condenser of the heat source or the heat utilizer, or a liquid pipe temperature detected at a liquid pipe outlet of the heat utilizer. 
     
     
         3 . The refrigerant leakage determination method according to  claim 2 , wherein the leak is determined to be present when the opening degree of the expansion valve of the heat utilizer during the normal operation increases so as to approach the opening degree of the expansion valve of the heat utilizer during the first trial operation. 
     
     
         4 . The refrigerant leakage determination method according to  claim 1 , wherein the first filling amount is 50% or more and less than 100% of the target filling amount. 
     
     
         5 . The refrigerant leakage determination method according to  claim 1 , further comprising:
 filling the refrigerant circuit with the refrigerant to a second filling amount that is larger than the first filling amount and smaller than the target filling amount; and   acquiring second trial operation data by performing a second trial operation of circulating the second filling amount of the refrigerant in the refrigerant circuit,   wherein determining the presence or absence of a refrigerant leak is performed by comparing the normal operation data, the first trial operation data, and the second trial operation data.   
     
     
         6 . The refrigerant leakage determination method according to  claim 5 , wherein filling the refrigerant circuit with the refrigerant to the second filling amount is performed after acquiring the first trial operation data. 
     
     
         7 . The refrigerant leakage determination method according to  claim 5 , wherein:
 the first filling amount is 50% to 70% of the target filling amount, and   the second filling amount is greater than 70% to less than 100% of the target filling amount.   
     
     
         8 . A refrigeration cycle apparatus, comprising:
 a heat source;   a heat utilizer;   a connection pipe that connects the heat source unit and the heat utilizer to form a refrigerant circuit; and   a controller including circuitry configured to control an operation of the refrigerant circuit,   wherein the controller includes circuitry configured to acquire first trial operation data by performing a first trial operation of circulating a first filling amount of a refrigerant in the refrigerant circuit, the first filling amount being smaller than a target filling amount.   
     
     
         9 . The refrigeration cycle apparatus according to  claim 8 , wherein the first trial operation data include data of an opening degree of an expansion valve of the heat utilizer, a degree of superheating at an outlet of an evaporator of the heat source or the heat utilizer, a degree of subcooling at an outlet of a condenser of the heat source or the heat utilizer, or a liquid pipe temperature detected at a liquid pipe outlet of the heat utilizer. 
     
     
         10 . The refrigeration cycle apparatus according to  claim 9 , wherein:
 the controller includes circuitry that is configured to determine the presence or absence of a refrigerant leak from the refrigerant circuit, and   the leak is determined to be present when the opening degree of the expansion valve of the heat utilizer during normal operation increases so as to approach the opening degree of the expansion valve of the heat utilizer during the first trial operation.   
     
     
         11 . The refrigeration cycle apparatus according to  claim 8 , wherein the first filling amount is 50% or more and less than 100% of the target filling amount. 
     
     
         12 . The refrigeration cycle apparatus according to  claim 8 , wherein the controller includes circuitry that is configured to acquire second trial operation data by performing a second trial operation of circulating a second filling amount of the refrigerant in the refrigerant circuit, the second filling amount being larger than the first filling amount and smaller than the target filling amount. 
     
     
         13 . The refrigeration cycle apparatus according to  claim 12 , wherein circulating the second filling amount of the refrigerant in the refrigerant circuit is performed after acquiring the first trial operation data. 
     
     
         14 . The refrigeration cycle apparatus according to  claim 12 , wherein:
 the first filling amount is 50% to 70% of the target filling amount, and   the second filling amount is greater than 70% to less than 100% of the target filling amount.