Refrigerator and defrost control method thereof

A defrost control method for a refrigerator including a storage chamber, an evaporator to cool the storage chamber, and a door to open and close the storage chamber, comprising:

• sensing opening and closing of the door;
• sensing absolute humidity in the storage chamber immediately before and after the opening and closing of the door;
• determining an estimated amount of frost formed on the evaporator using the sensed absolute humidity;
• and
• controlling a defrost operation based on the estimated amount of frost.

A refrigerator comprising:

• a storage chamber;
• an evaporator to cool the storage chamber;
• a humidity sensor sensing absolute humidity in the storage chamber;
• and
• a controller determining an estimated amount of frost formed on the evaporator using time segments in which the absolute humidity in the storage chamber decreases and controlling a defrost operation based on the estimated amount of frost.

A refrigerator, comprising:

• a storage chamber;
• an evaporator to cool the storage chamber;
• a humidity sensor sensing absolute humidity in the storage chamber;
• a door opening and closing the storage chamber;
• a door opening and closing sensor sensing the opening and closing of the door;
• and
• a controller sensing absolute humidity in the storage chamber immediately before and after the opening and closing of the door, determining an estimated amount of frost formed on the evaporator using the sensed absolute humidity, and controlling a defrost operation based on the estimated amount of frost.

A defrost control method for a refrigerator having a storage chamber, a door opening and closing the storage chamber, and an evaporator, comprising:

• sensing a first absolute humidity in the storage chamber after the door is closed;
• sensing a second absolute humidity in the storage chamber after the door is opened, following the door being closed;
• calculating a change amount of absolute humidity from the first and second absolute humidities;
• calculating an estimated amount of frost from the calculated change amount of absolute humidity;
• and
• determining whether to perform a defrost operation based on the estimated amount of frost.