Hi Folks,
I'm new to this forum. Have checked it out from time to time, but mostly hang out over and Donkey32.proboards.com. Only so much time in most of my evenings with two kids wanting to wrassle…
Anyway, i am glad to have finally tracked down some discussion about AGS. Thought i'd share a bit…
I have built one large house using Don Steven's approach, and consulted on another. I then designed and helped build another using a closed bottom battery (insulated bottom and sides and partially on top to ensure the 10 ft lag effect), and more recently i have installed a smaller similarly closed battery in a 600sq.ft addition. In this latter case i have set a 12" diameter duct along one end of a 3' deep battery, and heavily insulated around it to encourage the heat to migrate across the 10 ft or top-insulated mass to reach 6ft of uninsulated mass-to-floor-slab interface.
I switched to closed (bottom and sides) battery because here in the pacific north wet sub-terrainian moving water tends to draw heat away. The first place i built (Don's style) was on a mild slope with very well-draining sandy-rocky soil. The battery has 5 sensors showing that it harvests and transfers the heat as we hoped it would… but as soon as a major deluge of rain hits (as in 3 straight weeks of heavy rain) the temps through the whole battery drop sharply. We had originally planned to install a 4' deep curtain drain distal to the waterproof insulated cape, but did not for a few silly reasons. Might still add that feature. But we are not sure if it will do the trick.
The second house build with a Don style AGS was in a similarly constructed house (light clay walls, well insulated… etc) but on high ground with mild slope dropping away all sides. This battery offers up a steady 15c to 18c throughout the long cloud-covered months of our temperate rainforest winter. Topped up with a little masonry heater/cook stove this system is working very well.
The first build with the enclosed battery (a 1600sq.ft light clay 'big' cabin) we didn't put temperature sensors in the battery, but with about 700watts of surplus microhydro adding heat to the sub floor slab, and a 6" CSA RMH burning less than 1/2 cord a year the house is toasty warm.
Lots more to share about all of these projects… but just thought i'd get a start by saying the above and: AGS, PAHS, and Bob Ramlow's Solar Sand Bed approach all take a page from the ancient indigenous knowhow. People stayed warm enough in Tipi's and Pit houses because the central hearth fires sent roughly half of their heat into the surrounding earth. Nothing like soaking up conductive heat…
Masonry heaters and RMH's demonstrate the same principles. Decoupling heat generation from delivery via predictably (enough) slow conductivity through earthen mass…
I look forward to more discussion on all this.
but for now sleep time
