by pa_friendly_guy » Wed Jan 07, 2015 3:12 pm
I agree Matt. The design I have seen for passive cooling [ and I think it also worked as a heating unit in Winter ] had a huge air pipe buried for quite a distance in the ground. It has been a long time since I have seen the plans but I think it was a 4 foot pipe underground that went into an envelope system that encased the house. As I recall the pipe started at a spot below the house [ down hill from the house ] and it had a naturel rise to the house. This envelope encased the entire house [ you really had to include this idea when you built the house, the house plans had 2 wall systems ] and the air exited out the roof area. Your home was encased in 56 degree air in the summer to help keep it cool. In the winter it was encased in 56 degree air to help keep it warm. Increasing the interior temp from 56 to 72 was fairly easy. Your idea of using a much smaller pipe and using a cobb mass to stay cool could work, but when it is 90 degrees outside it may be like trying to steer the Queer Mary with a row boat.
The idea of opening a vent down low on the 1st floor on the wind side of the house and opening a vent high on the 2nd floor [ or at least higher than the 1st vent if you only have a one story home ] on the lee side of the house gives you a natural air flow that works with gravity. Having an outside air vent that is cooled by the air traveling underground for a distance and then entering the home, and being allowed to flow through the home naturally and exit at a higher point so after the air heats up it has a place to go does make sense. Its the volume of air needed to do the job that is a concern.
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