Wednesday, July 30, 2014

Timeline - Annualized GeoSolar

Six Years Ago

This is the first of three posts on the subject of Annualized GeoSolar  that, according to Wikipediamakes our green building project almost unique for the US .

Vacation with a Hidden Agenda
Early in my research on earth sheltering, I came upon a posting by Don Stephens* describing what he called "Annualized GeoSolar (AGS), which was incredibly intuitive and a game-changer for us.  So much so in fact that, about six years ago, we deliberately vacationed in the northern high desert in hopes of wrangling a visit to a house he had designed.

Fortunately, Don arranged a visit to an earth sheltered home just south of Spokane that he had designed for a retired veterinarian and his wife who built it themselves.  The unique feature, in addition to being a straw bale house and fully earth sheltered, was that it harvested the heat from the summer sun for its year-round comfort without conventional heating or air conditioning or depending upon passive solar from the winter sun.

Concrete structure with earth roof; no A/C but notice the chimney
Broad Picture of Earth Sheltering
My current understanding of earth sheltering is that, by the time of our visit out West, most of earth sheltering was still 1970ish concrete walls with either concrete or wood for earth contact roofs, sophisticated waterproofing and insulation fastened to the outside, passive solar during the winter supplemented by non-fossil-fuel heating such as wood, corn or pellet burners -- usually stoves, furnaces or masonry heaters. Actually, there were even many "earth homes" left over from earlier times that had little or no waterproofing and sometimes less-than-sophisticated insulation if they had any at all. Even the 1970ish homes had several drawbacks in varying degrees that gave us pause: (a) being at the mercy of 50 to 60 degree ground temperatures in winter, (b) in humid areas such as ours, condensation problems in summer, and (c) water problems during the wet season. However, with or without insulation and waterproofing, they still had a leg up on conventional homes with respect to energy conservation.  In summer they needed little or no air conditioning and in winter they were easy to heat so long as the occupants did not mind cold floors.

The Mueller Earth Sheltered Home Was Different
Here in the high desert we were standing in a house in a cold 6,000 heating degree zone with less mean percent of possible sunshine than we have in our less-than 5,000 heating degree zone in Metro St Louis.  It was a house that had not yet required help from its back-up electric baseboard heaters in the three years that Marilylenne and Joris Mueller had lived in it and a house with pleasantly warm floors during their long winters.

The Mueller's construction methods, which faithfully followed Stephen' recommendations (a summary paper by Stephens), gave new meaning to "minimalism" and "sustainability", which is to their credit but also contributed to their misfortune. Their iteration of AGS included a tad more minimalism than was good for long-term thermal performance of the AGS system.  They used straw bales for the insulation in their insulation-watershed umbrella (which we will soon define), some of which got so wet and non-insulating as to necessitate a wood burning stove.  In our view, their misfortune is not a knock on AGS but is a warning not to get too simplistic with it.   (The Muellers' "Mica Peak Residence" is the first example in Stephens' paper.)  

CLICK HERE for the second post on AGS.

CLICK HERE for the third post on AGS.

* Stephens' original paper -- -- is no longer available on the web.  However, it can be accessed in a round-about way via Stephens' original detailed paper .

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