Saturday, September 24, 2005
A/C colder when turned off?
Question: Turn the air-conditioning on in the car for a while and feel the cold air coming out of it. Then turn off the A/C but leave the fan on, it's colder - isn't it. Why would the air get colder after you turn it off?
Hints:
My guess is that when you turn the A/C off the motor stops working (and producing heat) but cooling plates are still cold (for a while). It's inevitable that the A/C unit dumps some heat from the engine and from the compressor etc. into the car. When you turn the A/C compressor off it stops producing this heat and for a while the air is cooler than with the A/C on.
Hints:
- Refrigerators and air-conditioners use energy to take heat from one place and put it in another.
- So there's a part that's cold and a part that's warm, the warm part is usually dumped in the air (outside).
- Air-conditioners have motors that are hot as well.
My guess is that when you turn the A/C off the motor stops working (and producing heat) but cooling plates are still cold (for a while). It's inevitable that the A/C unit dumps some heat from the engine and from the compressor etc. into the car. When you turn the A/C compressor off it stops producing this heat and for a while the air is cooler than with the A/C on.
# posted by Scott Kirkwood @ 11:39 AM 
