Let’s say it’s a warm day; the air temp is around 85 degrees.
The air IS still cooler than your body, so heat is flowing out of your body, but not fast enough to make you feel cool. You want to remove some heat from it more quickly, in order to feel cooler. How do you do it?
Well, one way is to use a fan. The fan moves air across your skin, and it feels cooler. Funny thing is, the air temperature is not any cooler than it was when it was sitting still…
What’s up with THAT?
Remember, when your skin gives up heat to the air, the air temperature around you rises slightly, so the heat flow slows down. That warmer air around your body is like a little blanket of still air.
If we can move that little blanket of warm air from near your skin, replacing it with cooler air, then the heat will flow away from your skin faster, and you will feel cooler.
This is the same effect as “wind chill factor” that you hear about when talking about the weather. Moving air removes heat a lot faster than still air.
Same effect with the heat exchanger… flowing air removes heat much more quickly than still air.
So in most refrigerators, two fans are installed.
An evaporator fan circulates air through the evaporator inside the freezer.
And on the outside of most refrigerators, a condenser fan circulates air through the condenser.
Air flow is important to a heat exchanger. If the tubes and fins are blocked, such as by ice or dust, or if either of these fans stops working the air won’t flow across the heat exchanger. Then it won’t transfer heat as it should, and the refrigerator and/or freezer will not be as cold as it should.