Method for controlling refrigerator

A refrigerator, comprising:

• a refrigerating compartment having a notch temperature N1 which is above 0° C.;
• a freezing compartment partitioned from the refrigerating compartment and having a notch temperature N2 which is lower than 0° C.;
• a deep freezing compartment accommodated in the freezing compartment and partitioned from the freezing compartment and having a notch temperature N3 which is lower than the notch temperature N2;
• a freezing evaporation compartment disposed behind the deep freezing compartment;
• a partition wall to partition the freezing evaporation compartment and the freezing compartment from each other;
• a freezing compartment evaporator accommodated in the freezing evaporation compartment to generate cold air for cooling the freezing compartment;
• a freezing compartment fan to supply the cold air of the freezing evaporation compartment to the freezing compartment;
• a thermoelectric module to cool the deep freezing compartment to a temperature lower than that of the freezing compartment;
• and
• a deep freezing compartment fan to cause air within the deep freezing compartment to forcibly flow,
• wherein the thermoelectric module comprises:
• a thermoelectric element comprising a heat absorption surface facing the deep freezing compartment and a heat generation surface that is an opposite surface of the heat absorption surface;
• a cold sink in communication with the heat absorption surface and disposed behind the deep freezing compartment;
• a heat sink in communication with the heat generation surface and is connected in series to the freezing compartment evaporator;
• a housing to accommodate the heat sink, the housing having a rear surface exposed to the cold air of the freezing evaporation compartment;
• and
• a controller,
• wherein, in response to a defrost period for freezing compartment defrost and deep freezing compartment defrost having elapsed, the controller is configured to:
• perform a deep cooling operation for cooling the deep freezing compartment and the freezing compartment to temperatures lower than lowermost satisfactory temperatures N22 and N32, respectively, and
• perform an operation for the freezing compartment defrost and an operation for the deep freezing compartment defrost after the deep cooling operation is ended,
• wherein, when the operation for the deep freezing compartment defrost starts, the controller is configured to close a freezing compartment valve to stop generation of the cold air by the freezing compartment evaporator to block a flow of the cold air to the heat sink,
• wherein at least portions of the operation for the freezing compartment defrost and the operation for the deep freezing compartment defrost overlap each other.