Refrigeration cycle apparatus and control method thereof

Abstract

A refrigeration cycle apparatus is caused to be in a normally operable state in accordance with the mixture ratio of difluoromethane occupying a refrigerant charged in the refrigeration cycle apparatus. A refrigeration cycle apparatus includes a refrigerant circuit including a compressor and performs a refrigeration cycle by circulating a refrigerant in the refrigerant circuit with the compressor. A heat-source-side controller judges the mixture ratio of difluoromethane occupying the refrigerant charged in the refrigerant circuit. The heat-source-side controller further performs control relating to the refrigeration cycle on the basis of the mixture ratio of difluoromethane judged by the judgement unit. The controller judges the mixture ratio of difluoromethane on the basis of a discharge temperature of the refrigerant of the compressor in operation under a prescribed condition or judges the mixture ratio of difluoromethane on the basis of weights of a plurality of types of refrigerants to be charged to the refrigerant circuit.

1 . A method of controlling a refrigeration cycle apparatus, wherein 
       the refrigeration cycle apparatus includes a first heat source unit having a first compressor and a second heat source unit having a second compressor, which are interchangeably connected to the refrigeration cycle apparatus and are detachable, and  
       the refrigeration cycle apparatus performs a first refrigeration cycle by circulating a refrigerant with the first compressor when the first heat source is connected and perform a second refrigeration cycle by circulating the refrigerant with the second compressor when the second heat source is connected,  
       the method comprising: 
 judging a mixture ratio of difluoromethane occupying a refrigerant in the second refrigeration cycle, the refrigerant being a mixture of a first refrigerant and a second refrigerant, the first refrigerant being a recovered refrigerant that has been recovered from the first heat source unit before the second heat source unit is connected, the second refrigerant being an additional refrigerant charged to a refrigerant circuit in the second refrigeration cycle; and  
 performing control relating to the second refrigeration cycle based on the mixture ratio of difluoromethane as judged.  
 
     
     
         2 . The method according to  claim 1 , wherein 
       the first refrigerant includes an R 410 A refrigerant, and 
       the second refrigerant includes an R 32  refrigerant.  
     
     
         3 . The method according to  claim 1 , wherein 
       the judgement of the mixture ratio of difluoromethane is based on a discharge temperature discharged from the refrigerant of the second compressor in operation under a prescribed condition.  
     
     
         4 . The method according to  claim 1 , the method further comprises, 
       determining a mixture ratio of difluoromethane in the second refrigeration cycle based on weights of the first refrigerant and the second refrigerant to be charged to the refrigerant circuit before charging the first refrigerant and the second refrigerant into the refrigerant circuit. 
     
     
         5 . The method according to  claim 2 , wherein 
       the mixture ratio of the difluoromethane occupying the refrigerant in the second refrigerant cycle is larger than a mixture ratio of pentafluoroethane occupying the refrigerant charged in the second refrigerant cycle. 
     
     
         6 . The method according to  claim 1 , the method further comprises, 
       controlling, when the mixture ratio of the difluoromethane in the refrigerant is greater than a prescribed ratio, a lowest number of revolutions of the second compressor to be greater than a lowest number of revolutions when the mixture ratio is the prescribed ratio. 
     
     
         7 . The method according to  claim 1 , wherein 
       the second compressor has an injection port between a suction side and a discharge side of a compression chamber and through which an intermediate-pressure refrigerant that is between a high-pressure refrigerant and a low-pressure refrigerant is injected,  
       the method further comprises: 
 when the mixture ratio of the difluoromethane in the second refrigeration cycle is larger than 50 wt%, performing injection into the injection port more frequently than when the mixture ratio of the difluoromethane is 50 wt%, wherein  
 the frequency of the injection is smaller than that of a frequency when the mixture ratio of the difluoromethane is 100 wt%. 
 
     
     
         8 . The method according to  claim 1 , wherein 
       the refrigerant circuit includes an expansion valve in the refrigeration cycle, 
       the method further comprises, 
       when the mixture ratio of the difluoromethane in the second refrigeration cycle is larger than 50 wt%, controlling an opening degree of the expansion valve at a time of starting the second compressor is smaller than when the mixture ratio of the difluoromethane is 50 wt%, wherein 
       the opening degree of the expansion valve at the time of starting the second compressor is larger than that of the opening degree when the mixture ratio of the difluoromethane is 100 wt%. 
     
     
         9 . A method of controlling a refrigeration cycle apparatus including a refrigerant circuit that includes a renewable heat source unit having a compressor and performs a refrigeration cycle by circulating a refrigerant, which is a mixture of a first refrigerant and a second refrigerant, with the compressor,  
       the method comprising: 
 judging a mixture ratio of difluoromethane occupying the refrigerant charged in the refrigerant circuit, and 
 performing control relating to the refrigeration cycle based on the mixture ratio of the difluoromethane in the refrigerant,  
 wherein  
 the first refrigerant is a recovered refrigerant recovered from the heat source unit before renewal in a case where the heat source unit is renewed, and 
 the second refrigerant is an additional refrigerant charged to the refrigerant cycle apparatus in which the heat source unit after renewal is incorporated.