METHANE DIGESTER

A methane digester produces biogas for cooking and heating from chicken and goose manure. The effluent is used to fertilize gardens and greenhouses as well as produce nutrient-rich algae in shallow ponds which in turn are fed back to the animals. It is also a better fertilizer than it was before digestion, and does not 'burn' plants if over-applied. The biogas consists of methane, carbon dioxide and hydrogen sulfide; it has 75% of the heating value of natural gas. A compressor packs it into an old propane tank for storage.

Duckweed and azolla are algae rich in protein [up to 40%].

They also grow fast [their mass can double in 48 hours].

Given that protein is a hart-to-get supplement for just about all kinds of livestock, growing these algae is good use of space, especially in a greenhouse where the ponds provide 'cooling' in summer, and 'heating' in winter.

Maybe I'll add some crayfish to see how that goes, i need protein, too...

 EFFICIENT WOOD FURNACES

Hundreds of years ago the masonry stove was invented both in Finland/Estonia/Russia and as a tiled version in Austria and Bavaria.

A well designed masonry stove extracts a whopping 90%

of combustion heat; that is the highest possible amount, since in order for the exhaust to leave the chimney and draw fresh air into the stove it must contain enough heat to want to rise. Masonry stoves are fired at up to 1500 degrees F; at these temperatures, there are no unburnt residues such as soot or creosote.

It is therefore possible to take the exhaust through lenghty passages embedded in masonry where most of the heat stays for many hours to come. In order to achieve good combustion the pieces of wood must be no more than three inch in diameter, which lends itself to regenerative methods of wood harvesting such as 'coppice'.