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If you leave a refrigerator open in a closed room, will it make the room cooler?
This is a tricky question, and the answer may surprise you: NO!
A fridge can be though of as a "heat pump". It takes air inside the fridge and cools it by removing heat from it. This heat has to go somewhere, though, and is usually blown out the back of the fridge by a little fan. (If you feel the back of a fridge on the outside it will usually be warm if the unit is running).
For this reason, when a fridge is running it is really warming up the room a little bit. In fact, since we canít design a fridge to be perfectly efficient (the 2nd law of thermodynamics guarantees this), some of the electrical energy gets converted to heat, so more heat gets dumped outside the fridge than gets pumped out, so even if you open the fridge door to let the cool air escape the fridge will still be heating the room more than cooling it.
(published on 10/22/2007)
Follow-Up #1: Keep the refrigerator door shut
If the room temperature when the refirgerator is being used with its door closed is X deg C, and when the refrigerator door is opened, will the room temeperature be still X?
The average room temperature in the room will rise. Of course there will be hotter spots and colder spots but we are talking about the average. The reason is that with the door open the temperature will start to rise inside the refrigerator. The thermostat will kick in and try to cool it back down. This means the motor is running, which means heat is being added to the room.
Keep the door shut. See the answer to question #1790 for more details.
p.s. The refrigerator of course pumps heat around, from its inside to its coils, but like Lee says it still ends up dumping net energy into the room. Mike W.
(published on 06/16/07)
Follow-Up #2: Regrigerators get hot making ice
If the refrigerator was making ice would the temperature still be higher?
- Anonymous (age 26)
Pomona, CA, USA
Yep. The second law of thermodynamics knows all, sees all. The more things you try to do,
the more energy will be wasted in heating the environment.
(published on 04/28/08)
Follow-up on this answer.