A: Mark,
According to the Alernative Crops Manual, "Jerusalem artichoke (Helianthus
tuberosus L.) is familiar to many as a weed but has some potential as a
crop plant. Native to the central regions of North America, the plant can
be grown successfully throughout the U.S. under a variety of temperature
and rainfall regimes. Several North American Indian tribes used Jerusalem
artichoke as food prior to the arrival of European settlers. The explorer
Champlain took Jerusalem artichokes from North America to France in 1605.
By the mid 1600s it was widely used as a human food and livestock feed
there."
More to the point, Jerusalem artichokes are a great resource for ethanol.
In the November 2004 paper, " A Shortcut to the Production of High Ethanol
Concentration from Jerusalem Artichoke Tubers" by Xiang-Yang Ge and Wei-Guo
Zhang, of the The Key Laboratory of Industrial Biotechnology, Ministry of
Education, China, states the Jerusalem artichoke contains nearly 20 % of
carbohydrates, and after fermentation yields can be up to 21 percent
ethanol.
Ethanol can be made with a positive energy balance, but actually it is a
moot point in the great State of Arizona. I support your idea of using
solar thermal for both fermentation and distillation, and there are some
interesting systems in the alcohol production literature.
Scott Sklar