Big Green: Naturally Ventilate a walkway, Plan C

[Susan Wittmack]

On 9/7/2006 11:10 AM, "biggreen-request at lists.biggreen.org"
<biggreen-request at lists.biggreen.org> wrote:

1. Natural Ventilation (Zoeteman, Mark R.)
Is anyone aware of a method to introduce natural ventilation through a
structure passively?
>(from Terry Brennan)
> *                     I'd consider trying to catch wind and pressurize one
> end and use a chimney at the other end to depressurize (like the Iranian
> mosque systems); there are a number of ways to accomplish this; this is a
> fairly simple situation so stack is easy to calculate and simple wind
> effects fairly simple (augmented intakes, flow limiting devices and
> Bournoulli exhaust outlets are way more complicated to model).  You could do
> a simple CONTAM model or a more sophisticated cfd model using TMY2 data

And the easy way out is to install solar powered vent fans either on the
ceiling or on the walls near the ceiling, spaced as desired/needed. They
operate on 24V DC - so no electrical (no fire issues). Put as many as 3 fans
on one 120V panel. If the sun is up or UV can get through the clouds, they
operate. I'm presuming in a northern climate that at night, there are no
businesses open to walk through or it is cool enough that the fans don't
need to operate. In the winter, either switch them off by installing a
switch at the fuse point, or pull the fuses, or leave them on to remove
mildew-creating moisture.
    There are many "brands" available ranging from 850cfm units to 1200cfm
units. Avoid the units with the solar panel attached to the top of the fan
as these solar panels are generally too small to maximize power to the fan
unit AND, you may not be able to place them to optimize their exposure to
the sun. Indeed, if the walkway is in any way shaded, the solar panels may
have to be remotely located.
    Google "solar-powered attic fans". CET Solar and Advanced Energy are
among the mfgs.
Susan Wittmack, RA
San Antonio TX
Susan at abcvisions.com