Passive Annual Heat Storage

Carl Nystrom wrote:This thread might be of interest

https://permies.com/t/169882/permaculture-projects/Winter-ATI-test-Allerton-Abbey

There was another test the previous season which is documented here:

https://permies.com/t/180/120233/permaculture-projects/Jen-Boot-Camp-Allerton-Abbey#1028790

Thanks for your response, Carl. Those are wood framed, right?


So far, I am not convinced that their current design is able to store enough heat during the summer, so the indoor temperature is trying to return to a baseline that is too cool to be comfortable.

The thing that puzzles me is how it all just died. Did John Hait get sued or something? Was ther ever any other testing done besides what he said he did on the Missoula GeoDome?

To Paul Wheaton: Did you ever do any followup to your above mentioned article? Do people still use and live in the Missoula GeoDome?

I think the idea is sound. Thermal mass does work. I remember a cathedral in Sweden that was built with walls so massive that in the summer a torrent of cool air came pouring out of it even though they left the doors open all day. In the winter it was supposedly warm inside, but I suspect that "warm" is relative. When you step in out of a snow storm, 55F feels pretty nice. Soil has a sine-curved temperature graph - with the peaks and valleys converging with depth until you hit the stable ground temperature at 30ish feet down. If you want to change the amplitude of that graph, you are going to have to force more energy into the system, and then likely use insulation to keep it there. I think using as much winter solar gain as possible is likely key.

To me it is a fascinating idea. I am more interested in trying to cool an underground space for food storage, but the principle is the same. Air is not capable of carrying very much energy relative to soil, so I suspect that to significantly change the temperature of even a moderately sized underground space would take a LOT of airflow.

My take on what the Hait book said was that because the Earth heat sink was insulated and "kept dry" with the many layers of overlapped poly that the house with its uninsulated walls became the heat exchanger which went two different directions depending on the outside season.

I am guessing that the reason you dont see more of this being done is simply cost and complexity of building anything underground. If you build a tight structure on the surface with r-60 insulation all around and heat exchanging air ventilation, you could probably keep it comfortable inside with waste heat (cooking, electric devices and body heat) in a modestly mild climate.

You could well be right, Carl. And actually trying to control such a huge expanse of Earth to keep it dry, the crucial thing, may well be something beyond our capability. But again, I am just wondering about the silence regarding the process and the houses that were built. I called one engineer who still had something on the Net, asked for him and a lady asked who was calling. I explained and she said he had died ten years ago. I stumbled with copious apologies and left the conversation still as ignorant about where this sits as a few weeks ago when I started wondering. If anyone has any further info on this, did any universities do anything, is John Hait still alive, ... I'd like to know.

Glenn Herbert wrote:I suspect that PAHS depends for viability on an area where soil has no groundwater nearby and is well-draining, thus not very conductive; and on being where the average annual temperature is not too low. The earth will equilibrate to the average local air temperature, so PAHS in Alaska is probably doomed unless the entire thermal mass is insulated on all sides, top and bottom.

I am thinking PAHS had some other major issues, Glenn, cause it is like a disappeared see eye eh non favorite persona, I can't seem to find anything recent on it, no discussion at all. I must admit that I haven't exhausted all potential sources. I am gonna ask the DWG people at Univ of Minnesota. I vaguely remember something from somewhere that the UofM did something as regards PAHS.  

I did a design for a not-exactly-PAHS industrial/warehouse structure in college about 1979, using water storage tanks buried under/around the building and solar panels to warm the water. I would love to use the PAHS concept for my house, but as there is a constant trickle of water from my foundation drain, I could never get above 55 degrees. I will have to be satisfied with a storage tank in the basement for a drainback system.

Terry Byrne wrote:Hello to all Permies!!

I have/possess and just recently reread the John Hait book [2013 edition]  Passive Annual Heat Storage. I have been doing further research, looking and it seems to have just died. I came across a Paul Wheaton article which I had also seen a few year ago, link below.

https://www.makeitmissoula.com/2014/05/passive-annual-heat-storage/

Does anyone know what has happened to this idea, to John Hait, ... is there anyone still pursuing this? Are the houses that have been built still being used, still functioning after all these years, according to the initial plan? To me these seem ideal to RMHs.

Any and all info would be much appreciated.

Terry[