Big Green: reversible ceiling fans vs. natural forces

[sagefarm at comcast.net]

Dear Peter:

While blowing air down may increase local air velocities enough to increase evaporation from people's skins to make them cooler, this approach, by attempting to push warm air down, goes against the natural forces that want to let warm air rise.  

After all, the air at the top of the room that would be pushed down would be warmer than the incoming air, would it not?

What is the pathway for the air entering the room, that will replace the air rising out of it?  Is there anyway this incoming air can have its local velocity increased?

Could the volume of air moving through the room be increased by having a solar chimney at the very top of the planned exhaust route?  This way, warmth from the sun would make the exiting air even more buoyant and would work more with free natural forces, as opposed to using electricity to turn a fan. 


Just some thoughts and questions.

Sincerely,

David W. Bearg, PE, CIH
Green Building Scientist
LIFE ENERGY ASSOCIATES
20 Darton Street
Concord, MA 01742
www.LifeEnergyAssoc.com
978-369-5680

 -------------- Original message ----------------------
From: "Peter Reppe" <peterr at solarc-ae.net>
> Greetings,
> We wanted to use ceiling fans, mounted in each of three roof monitors of a
> one-story bldg, for passive cooling purposes: direct the air down at poeple
> during the daytime, and reverse the fans at night to push air out the roof
> monitors (drawn in through a long band of windows, cracked open/secured just a
> bit)....
> 
> I was hoping that someone on this list had found a ceiling fan that allows a
> change in direction via remote control (or wall switch)...or any other
> solution for reversing the direction of all three fans at the same time (and
> that doesn't require a ladder).
> 
> All I'm finding are fans with remote controls for fan speed levels and the
> light.
> 
> Thanks in advance...Cheers,
> Peter
> 
> --
> ..............................................
> Peter Reppe
> Solarc Architecture/Engineering
> 223 W. 12th Ave.
> Eugene, OR, 97401
> 
> www.solarc-ae.net
> 
> ph: 541.349.0966
> ..............................................
> 
> 
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