Refrigerator and control method thereof

Abstract

Disclosed are a refrigerator and a control method thereof. The refrigerator according to one aspect includes a main body having a storage chamber; a compressor configured to compress a refrigerant; a condenser configured to condense the refrigerant compressed by the compressor; an evaporation expander configured to depressurize the refrigerant condensed by the condenser; a first evaporator configured to evaporate the refrigerant depressurized by the evaporation expander and thus to cool the storage chamber; a condensing expander installed between the condenser and the evaporation expander and configured to depressurize the refrigerant condensed by the condenser; and a subsidiary condenser installed between the condensing expander and the evaporation expander and configured to condense the refrigerant depressurized by the condensing expander.

What is claimed is: 
     
         1 . A refrigerator comprising:
 a main body that has a storage chamber;   a refrigeration cycle located in the main body and configured to supply cold air to the storage chamber,   wherein the refrigerant cycle includes:
 a compressor configured to compress a refrigerant; 
 a condenser configured to condense the refrigerant compressed by the compressor; 
 a valve device connected to an outlet of the condenser; 
 a first branch passage that connects the valve device to the compressor to flow a portion of the condensed refrigerant discharged from the condenser; 
 a second branch passage that connects the valve device to the compressor to flow a remaining portion of the refrigerant discharged from the condenser; 
   a cold storage expander located at the first branch passage and configured to depressurize the portion of the condensed refrigerant; and   a cold storage evaporator located at an outlet side of the cold storage expander and configured to evaporate the depressurized refrigerant discharged from the cold storage expander;   a subsidiary condenser located at the second branch passage;   a condensing expander located at the second branch passage and between the subsidiary condenser and the valve device, wherein the subsidiary condenser is configured to condense the remaining portion of the refrigerant depressurized by the condensing expander;   an evaporation expander located at an outlet side of the subsidiary condenser and configured to depressurize the remaining portion of the refrigerant condensed by the subsidiary condenser;   a first evaporator configured to evaporate the refrigerant depressurized by the evaporation expander in order to cool the storage chamber; and   a second evaporator located at an outlet side of the cold storage evaporator and configured to evaporate the refrigerant evaporated by the cold storage evaporator.   
     
     
         2 . The refrigerator according to  claim 1 , further comprising a check valve located at an inlet side of the first evaporator and configured to guide a one-way flow of the refrigerant toward the compressor. 
     
     
         3 . The refrigerator according to  claim 1 , further comprising a cold storage part that has a phase change material (PCM) therein, wherein the subsidiary condenser and the cold storage evaporator are located inside the cold storage part, and
 wherein the cold storage part exchanges heat with each of the subsidiary condenser and the cold storage evaporator.   
     
     
         4 . The refrigerator according to  claim 2 , wherein the valve device is a three-way valve that has one inlet port, and first and second outlet ports,
 wherein the first branch passage is branched from the first outlet port, and   wherein the second branch passage is branched from the second outlet port.   
     
     
         5 . The refrigerator according to  claim 4 , further comprising an input part configured to receive an input of a desired temperature of the storage chamber; and a temperature sensor located inside the storage chamber,
 wherein, based on a temperature detected by the temperature sensor being equal to or higher than the desired temperature, the valve device opens the first outlet port and closes the second outlet port in order to guide the refrigerant flow toward the cold storage evaporator.   
     
     
         6 . The refrigerator according to  claim 5 , wherein, based on the temperature detected by the temperature sensor being lower than the desired temperature of the storage chamber, the valve device opens the second outlet port and closes the first outlet port in order to guide the refrigerant flow toward the first evaporator. 
     
     
         7 . The refrigerator according to  claim 1 , wherein the storage chamber comprises a refrigerating chamber and a freezing chamber, and wherein the first evaporator is located at a rear wall of the freezing chamber, and the cold storage evaporator and the subsidiary condenser are located at a rear wall of the refrigerating chamber. 
     
     
         8 . A control method of operating a refrigerator comprising a main body that has a storage chamber, the control method comprising:
 supplying, by a refrigeration cycle located in the main body, cold air into the storage chamber, wherein the refrigerant cycle includes:
 a compressor configured to compress a refrigerant; 
 a condenser configured to condense the refrigerant compressed by the compressor; 
 a valve device connected to an outlet of the condenser; 
 a first branch passage that connects the valve device to the compressor to flow a portion of the condensed refrigerant discharged from the condenser; 
 a second branch passage that connects the valve device to the compressor to flow a remaining portion of the refrigerant discharged from the condenser; 
 a cold storage expander located at the first branch passage and configured to depressurize the portion of the condensed refrigerant; and 
 a cold storage evaporator located at an outlet side of the cold storage expander and configured to evaporate the depressurized refrigerant discharged from the cold storage expander; 
 a subsidiary condenser located at the second branch passage; 
 a condensing expander located at the second branch passage and between the subsidiary condenser and the valve device, wherein the subsidiary condenser is configured to condense the remaining portion of the refrigerant depressurized by the condensing expander; 
 an evaporation expander located at an outlet side of the subsidiary condenser and configured to depressurize the remaining portion of the refrigerant condensed by the subsidiary condenser; 
 a first evaporator configured to evaporate the refrigerant depressurized by the evaporation expander in order to cool the storage chamber; and 
 a second evaporator located at an outlet side of the cold storage evaporator and configured to evaporate the refrigerant evaporated by the cold storage evaporator. 
   
     
     
         9 . The control method of  claim 8 , further comprising guiding, by a check valve located at an inlet side of the first evaporator, a one-way flow of the refrigerant toward the compressor. 
     
     
         10 . The control method of  claim 8 , further comprising exchanging, by a cold storage part that has a phase change material (PCM) therein, heat with each of the subsidiary condenser and the cold storage evaporator, wherein the subsidiary condenser and the cold storage evaporator are located inside the cold storage part. 
     
     
         11 . The control method of  claim 9 , further comprising:
 branching the first branch passage from first outlet port of the valve device; and   branching the second branch passage from second outlet port of the valve device.   
     
     
         12 . The control method of  claim 11 , further comprising receiving, by an input part of the refrigerator, an input of desired temperature of the storage chamber, wherein a temperature sensor is located inside the storage chamber, and wherein, based on a temperature detected by the temperature sensor being equal to or higher than the desired temperature, the valve device opens the first outlet port and closes the second outlet port in order to guide the refrigerant flow toward the cold storage evaporator. 
     
     
         13 . The control method of  claim 12 , further comprising:
 based on the temperature detected by the temperature sensor being lower than the desired temperature of the storage chamber, opening the second outlet port and closing the first outlet port, by the valve device, in order to guide the refrigerant flow toward the first evaporator.