| CPC F25B 49/02 (2013.01) [F25B 41/20 (2021.01); F25B 45/00 (2013.01); F25D 11/022 (2013.01); F25B 2400/19 (2013.01); F25B 2500/19 (2013.01); F25B 2600/024 (2013.01); F25B 2600/2515 (2013.01); F25B 2700/151 (2013.01)] | 20 Claims | 

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               1. A method for controlling a refrigerator, the refrigerator including a refrigerating room evaporator, a freezing room evaporator, a compressor configured to supply refrigerant to each of the refrigerating room evaporator and the freezing room evaporator and to use the refrigerant as a lubricant for a piston, and a refrigerant control valve configured to control flow of the refrigerant from the compressor to each of the refrigerating room evaporator and the freezing room evaporator, the method comprising: 
            determining whether a condition for performing a refrigerant recovery operation is satisfied, wherein the refrigerant recovery operation is an operation for causing the refrigerant in at least one of the refrigerating room evaporator or the freezing room evaporator to return to the compressor; 
                based on the condition of the refrigerant recovery operation being satisfied, performing the refrigerant recovery operation; 
                determining a first driving input value applied to the compressor at a first time point corresponding to a start time point of the refrigerant recovery operation; 
                determining a second driving input value applied to the compressor at a time point subsequent to the first time point during the refrigerant recovery operation; 
                determining a ratio of the second driving input value to the first driving input value; and 
                terminating the refrigerant recovery operation based on the ratio of the second driving input value to the first driving input value being less than a preset ratio. 
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