A refrigerator comprising: 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 ; a refrigerant pipe configured to guide a flow of the refrigerant condensed by the condenser ; characterized by a first branch passage branched from the refrigerant pipe; a second branch passage branched from the refrigerant pipe and in which the evaporation expander , the first evaporator , the condensing expander , and the subsidiary condenser are installed; a valve device installed at the refrigerant pipe and configured to branch the refrigerant to the first and second branch passages , a cold storage expander configured to depressurize the refrigerant condensed by the condenser ; and a cold storage evaporator configured to evaporate the refrigerant depressurized by the cold storage expander , wherein the cold storage expander and the cold storage evaporator are installed at the first branch passage ; and further comprising a cold storage part having a phase change material, PCM, therein and in which the subsidiary condenser and the cold storage evaporator are installed, wherein the cold storage part exchanges heat with each of the subsidiary condenser and the cold storage evaporator . 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 ; a refrigerant pipe configured to guide a flow of the refrigerant condensed by the condenser ; characterized by a first branch passage branched from the refrigerant pipe; a second branch passage branched from the refrigerant pipe and in which the evaporation expander , the first evaporator , the condensing expander , and the subsidiary condenser are installed; a valve device installed at the refrigerant pipe and configured to branch the refrigerant to the first and second branch passages , a cold storage expander configured to depressurize the refrigerant condensed by the condenser ; and a cold storage evaporator configured to evaporate the refrigerant depressurized by the cold storage expander , wherein the cold storage expander and the cold storage evaporator are installed at the first branch passage ; and further comprising a cold storage part having a phase change material, PCM, therein and in which the subsidiary condenser and the cold storage evaporator are installed, wherein the cold storage part exchanges heat with each of the subsidiary condenser and the cold storage evaporator . <EOS>