permaculture

[stephan leimroth <slimerote@yahoo.com>]

hello,

does anyone have experience with solar chimneys?  i'm
trying to ventilate a metal roofed house,  but i can't
find any info on sizing.  i'm thinking of installing 3
12in. diameter metal vent tubes (painted black) maybe
6ft tall for a 35 by 25ft space.  
my main concern is getting the ratio of metal surface
area of the tube to volume of the tube correct.

any suggestions would be welcomed.

stephan.
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