This is probably not a bad time to share some information. When I finally get to the “final plans” stage (God I hope it’s soon) I will be using the PAHS concept. For the solar architecture/engineering portion of my plan I will be using the services of a solar architect. Don Stephens (GreenerShelter.org) is the man with the plan. When you go to his site, check out the Mica Peak PAHS house. This house is earth sheltered passive solar and the design is Don’s. I’ve been to this house. It is truly wonderful. It’s tiny, one bedroom, one bath, but cleverly designed and huge in so many ways. Jerry Mueller, owner/builder, has embedded sensors in the ground beneath his home and has kept detailed logs of the temperature changes during the conditioning of his PAHS system.
The passive solar design used in the Mueller home is very clever. Don incorporated a solar chimney in his design and the system is entirely automatic, with the solar chimney vent opening and closing based on temperature inside the chimney. The release of heated air from the chimney draws the air from the heater located outside the PAHS envelope through tubes under the house which connect to the solar chimney. Changes were made in the original plan due to outgassing of some of the recycled materials and direct venting into the living space was removed.
Due to the potential for outgassing and the possibility of mold and mildew in the tubes, I am planning to use loops that return to the “heater” without entering the living space. Because I will not be using a solar chimney (my current plan would allow for this, but I think recycling the heat is a better option), I will draw the air through the tubes using solar powered fans triggered by a difference in temperature between the returning air and the heated air.
In my research on direct solar gain, passive solar, and hybrid systems, I have determined the best system for my location, house plan and climate to be the above. You can read more about PAHS by doing a internet search for passive annual heat storage and annualized geo-solar.