posted 9 years ago
It has been more than a few years, but I remember reading about a passive heating/cooling design in Israel that used double stone walls and vents (screened, of course) placed along the bottom and top of both. You adjust the openings of the vents based on outside temperatures and desired interior temperatures. You may get better performance with this type of wall by insulating the exterior side of the interior wall. You could use perlite (or vermiculite, pumice, expanded clay/shale, foamed glass, or sawdust) mixed with clay or cement, rather than more conventional insulation.