[GSBN] Natural Ventilation

[SABALE]

Check out condorkenetic.com.au,
surely with a name like condor it has a parent company in north America.
It does not look like they do anything in 4 inch.

another option we have used is a closable air-conditioning vent , this has a 
central square  that turns closing
a butterfly valve ( approx 10 inch ),  a corresponding square on a long or 
extendable pole easily enables you to close
and oven the vent seasonally.

the only thind close to 4 inch I have seen is from the under dash of 1970's 
cars,
that shuts off the hot air ductiong to the vents, cable operated , would 
need some vent cover ( a condor ) on the outside.

will look in the shed, as I think I have a couple.
Cheers Lance
www.houseofbales.com.au
----- Original Message ----- 
From: "Frank Tettemer" <frank at livingsol.com>
To: <GSBN at sustainablesources.com>
Sent: Tuesday, August 30, 2011 9:55 AM
Subject: [GSBN] Natural Ventilation


> Hi All,
>
> Here's a ventilation question, for all the fresh air fans on this list.
> I'd like to use gravity/convection ventilation, and I need to plan a way 
> of opening and closing the vent.
>
> We're building a small straw bale home for a couple this year that has 
> engineered trusses.
> The upper cord, defining the roof surface, is 6/12 pitch.
> Inside, the ceiling in one area of the house is a 3/12 pitch.
> The walls are 8'-3" at the truss plate, and the central high point in the 
> ceiling is 10'6".
>
> The home will be heated with an ESSE wood cooker, and has a 4" diameter 
> ABS pipe emerging from the floor, behind the ESSE, bringing in fresh air, 
> from below ground, and will be ducted to the combustion air inlet on the 
> wood stove for the winter.
> During the summer, a 4" TEE in this air pipe will allow earth-cooled 
> outside air into the home.
> (We've provided condensation drainage, as well as a straight clean-out, 
> from the outside of the home, to deal with potential mildew troubles.)
>
> What I would like to do is provide a 4" exhaust vent, up at the peak of 
> the interior ceiling, to complete the ventilation scheme, which relies on 
> gravity to power the flow, i.e., hot ceiling air vents upward, through the 
> attic space, while colder earth-tempered air is drawn in from the outside 
> in the house's North shadow, to the centre of the home, near the stove.
>
> I know that while windows are open, the earth-tempered air may not flow 
> inward with any serious pressure.
> But the hot air, at ceiling height of 10'-6" will surely flow upwards and 
> out, no problem. This is the flow we're looking for, during the hot, 
> Summer months.
>
> Back to my original question around ventilation. How do I open and close 
> that 4" ceiling vent?
> Is there anything on the market that has very positive closure, and could 
> be used?  A good closure system will be necessary during the long winter 
> months, here in Ontario, near Algonquin Park, which has weather similar 
> but colder than Ottawa, Ontario.
>
> I'm sure this has been done before, and there must be a practical way to 
> control this venting.
> Any ideas?
>
> Frank
>
> -- 
> Frank Tettemer
> Living Sol ~ Building and Design
> www.livingsol.com
> 613 756 3884
>
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