3
$\begingroup$

I was laying in bed one day, looking at my ceiling fan, when I wondered, "Doesn't the ceiling fan, because it makes wind, cause wind chill, which 'wicks' heat away from me -> making me feel cooler, because that's how wind chill works. But because heat energy cannot be created nor destroyed, won't the wicked heat go into the air (among other places) and make the air warmer? This question also applies to wind in general, not just wind from an innocent ceiling fan. Any support is appreciated.

And final note: If a ceiling fan doesn't heat up the area, is there a practical instance where some source of wind would 'wick' away enough heat to actually heat the medium the wind is occurring in?

$\endgroup$
  • 1
    $\begingroup$ The ceiling fan imparts kinetic energy into the air stream that it is stirring up. Due to viscosity effects, this kinetic energy turns into a small amount of heat in the room, and slightly increases the temperature of the air in the room. $\endgroup$ – David White Sep 29 at 2:35
2
$\begingroup$

If the air is stationary, the air near your body will heat up to (about) body temperature, reducing your heat loss. If the air is moving, you will lose more heat to the air, which will raise the average temperature of all the air in the room. However, if the air is moving the air comes into better contact with the walls, losing more heat. At the level of this experiment it is not fair to assume the air in the room is isothermal. It is hard to see which effect is greater. I suspect you are correct that the average temperature will rise with a fan, but the temperature you experience will fall.

$\endgroup$
1
$\begingroup$

We, people and animals, cool ourselves by perspiration, when water in our body evaporates, changing its state from the liquid one to a gaseous one, taking thermal energy from our body.

While we are perspiring, the air near our bodies becomes wetter — its humidity increases, which prevent (or reduce) us to continue perspiring, and, consequently, cooling ourselves.

Fans blow away the saturated air, and we may continue perspiring, cooling ourselves.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.