Wednesday, April 22, 2009

War Of The Refrigerator

So with your new found information that refrigerators take the heat out of your food and push that heat out the backside (underside) of the refrigerator, I have a few questions for you:

What happens to your kitchen temperature after you fill the refrigerator with warm soda and close the refrigerator door?


1. The kitchen will stay the same temperature
2. The kitchen will get cooler
3. The kitchen will get warmer




Remember: the soda is getting colder. . .

Too easy? The answer is number three. The soda started out as warm, and within an hour or so the refrigerator makes it cold. As Newton describes when he stated "Energy can neither be created or destroyed," that heat has to go somewhere. As the refrigerator removes the heat from the warm soda (making it cold for your drinking enjoyment) it releases that heat into the kitchen, making the kitchen warmer.


What happens to the kitchen temperature if you leave the refrigerator door open?

1. The room gets colder
2. The room stays the same temperature
3. The room gets warmer




If you guessed that the room would get colder ask yourself: Where is the heat going? Heat cannot be destroyed so it must be going somewhere.

If the refrigerator was perfectly efficient at removing heat from your soda (the inside) the room would stay the same temperature. It would remove heat from the air closest to the walls of the refrigerator and push it out of the coils on the backside. The air would then mix together and go back to the same temperature as before.

But refrigerators are not perfectly efficient. In the process of moving that heat the refrigerator creates some of its own heat. Another way of saying that: as the compressor runs (the thing you hear kick on from time to time) some electricty is wasted (lost) as heat. Same as running any other kind of motor, there is always some loss (friction etc) that shows up as heat.

So, because the motor in your refrigerator gets warm when it runs (on top of moving heat around), any room exposed to an open refrigerator will actually become warmer, and not colder. Don't tell your parents.

2 comments:

RT said...

Very nice. . .
When's the next post coming?

gerard said...

Working on it now. Thank you for the interest.