How a fridge keeps food cold
How a fridge moves heat from its inside into your kitchen with a loop of refrigerant.
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Transcript
A fridge keeps food cold by moving heat out of it. The heat goes from the inside of the fridge into your kitchen. That’s why the back of a fridge feels warm.
It moves the heat with a liquid called refrigerant, which flows around a closed loop of pipes.
The cooling comes from evaporation. When sweat dries on your skin, it takes heat with it, and you feel cooler.
Inside the fridge, the refrigerant evaporates in thin pipes. As it turns into a gas, it takes heat from the air and the food, so the inside gets colder.
A pump called the compressor then squeezes the gas. Squeezing it makes it hot, hotter than your kitchen.
In the coils at the back, the hot gas gives its heat to the kitchen air. As it cools, it turns back into a liquid.
The liquid then goes through a narrow opening. The pressure drops and the liquid gets very cold. Then it flows back inside, and the loop starts again.
A thermostat switches the compressor on and off, so the inside stays at the temperature you set.
