Or, as their web site calls it (a bit pretentiously?),
[size=24]The Science of Enertia[/size]
Seems like I saw double envelope houses in the very old days of interest in solar/highly efficient housing--the 80's maybe?--and dismissed as "interesting but not do-it-yourself."
Doesn't mean it doesn't work. And it's the kind of thing that the log cabin and other thermal mass guys have been touting for years, coupled with the double envelope.
http://www.enertia.com/science.htm
They have at least 3 patents:
1 United States Patent 4,280,479
Sykes, Jr. July 28, 1981
Solar heat collector (not used)
2 United States Patent 4,621,614
Sykes, Jr. November 11, 1986
Heat storage means (The house system - worth reading)
Originally U.S. patent Ser. No. 478,068, Filed Mar. 23, 1983, now abandoned, entitled
IMPROVED HEAT STORAGE MEANS
3 United States Patent 6,933,016
Sykes, Jr. August 23, 2005
Method of increasing latent heat storage of wood products (wood treatment)
It seems that they have amalgamated a lot of techniques with a common goal.
If I am not wrong, what they have is more elaborated than just one or two techniques, and they have successful practical experience.
I would love to visit one of those houses.
If I would try this way, It would be a D shape house, with a living roof, vertical logs walls inside, a soapstone masonry stove/trombe wall and the solar space on S and strawbale / super insulated external walls on N/E/W.