Refrigerator

A refrigerator, comprising:

• an evaporator configured to perform heat exchange;
• a defrost heater configured to operate to remove frost formed on the evaporator;
• a temperature sensor configured to detect an ambient temperature of the evaporator;
• a controller configured to control the defrost heater;
• a refrigerating compartment fan;
• and
• a freezer compartment fan,
• wherein, in response to a defrosting operation start time point arriving, the controller is configured to perform a defrost operation mode including a pre-defrost cooling mode, a heater operation mode, and post-defrost cooling mode,
• perform a continuous operation mode, in which the defrost heater is continuously turned on, and a pulse operation mode, in which the defrost heater is repeatedly turned on and off based on the defrost operation mode,
• wherein the heater operation mode includes:
• a first time period in which the continuous operation mode is performed,
• a second time period in which the pulse operation mode is performed,
• a third time period in which the defrost heater is turned off after the second time period,
• wherein during the third time period, the freezer compartment fan is turned off,
• wherein the pre-defrost cooling mode before the heater operation mode includes:
• a fourth time period in which the refrigerating compartment fan is turned on and the freezer compartment fan is turned off, and
• a fifth time period after the fourth time period in which the refrigerating compartment fan is turned off and the freezer compartment fan is turned on.