On Fri, 03 Aug 2007 10:10:26 +0200, Mxsmanic
wrote:
>David Horne, _the_ chancellor (*) writes:
>
>> Yet I always felt cooler with it in very hot weather.
>
>No doubt, but your subjective impression does not invalidate the laws of
>thermodynamics that govern the operation of fans.
>
>Fans add heat to the air simply by accelerating it. The motors in the fans
>also add heat to the air. In a perfectly insulated room, the temperature will
>rise continuously as long as a fan operates.
>
>> Do you sweat, like normal people?
>
>Yes, but I know how it all actually works, and I have no illusions about fans
>"making things cooler." Fans create air movement that helps sweat to
>evaporate, but at the same time they raise air temperature and the evaporation
>they assist raises humidity. This is why fans are not suitable for very hot
>or humid environments, and also are unsuitable for closed rooms.
While fans are most useful in dry climates where they can aid in
the body's own evaporative cooling, they can be helpful in humid
climates as well, where they move the air across your body and
remove the buildup of stationary humid air next to your body.
--
************* DAVE HATUNEN (hatunen@cox.net) *************
* Tucson Arizona, out where the cacti grow *
* My typos & mispellings are intentional copyright traps * |