Today, all but the smaller, apartment-sized refrigerators are self-defrosting. Self-defrosting means what it implies--though frost continues to accumulate inside the refrigerator, it melts automatically. The self-defrosting system has three functional components:
automatic defrost
The timer is like a clock. It continually advances, 24 hours a day. Every 6 to 8 hours, the timer turns off the cooling system of the refrigerator and turns on the defrost heater.
The defrost heater is similar to the burners on an electric stove. It's located just beneath the cooling coils, which are concealed behind a panel in the freezer compartment. The heater gets hot. And, because it's close to the cooling coils, any ice or frost build-up melts.
As the frost and ice melt, the resulting water drips into a trough. The trough is connected to a tube that drains the water into a shallow pan at the bottom of the refrigerator. The water is then evaporated by a fan that blows warm air from the compressor motor over the pan and out the front of the refrigerator.
The process ends after either the amount of time specified on the timer or when the defrost thermostat near the cooling coils senses that the heat near the coils has reached a specific temperature.
You'll more quickly understand refrigerator cooling systems if you think of their action as "removing heat from the air in the refrigerator" rather than "cooling the air in the refrigerator." All residential refrigerators work on the same principal for cooling. They all have:
No comments:
Post a Comment