[permaculture] if there were a benefit to deforestation...

Lawrence F. London, Jr. venaurafarm at bellsouth.net
Thu Jan 7 22:50:58 EST 2010


Steven & Margaret Eisenhauer wrote:

> The claim to be able to burn
> wet bio material is especially important given he is condensing the latent
> heat of combustion, therefore garnering the lion share of heat in the
> material, especially wet material.  Most burners - even the rocket design
> looses the latent heat of combustion in order to obtain the stack effect for
> draft, providing combustion air without a fan driven by electricity. I have
> wondered if a condensing gas furnace heat exchanger could be coupled with a
> wood stove with similar effect. 

That's exactly what came to mind as I read your post. Utilize two units, 
one to volatilize combustible gases
in the fuel and render it into biochar, deliver those gases through a 
pipe to a second stove, one used for cooking or heating water.

Sounds like a simple setup. I need a design for the first unit, the 
biochar cooker. The two units should be combined into one somehow,
and designed to prevent backfiring into the biochar cooker causing an 
explosion (the kind that can happen with an ordinary wood stove with the 
draft almost closed as fuel burns very slowly and generates lots of 
volatile gases.

> The bio char movement's thinking is to simply make the char without using
> the resulting BTUs produced which I think is a terrible waste of good wood
> when most of the world relies on wood for cooking. Given that 75% if the
> heat in wood is released during the gasification phase there is a desire to
> make the char while cooking or heating water with the resulting char sold to
> buy food in the third world. 

Maybe we can come up with a good design for such a super efficient 
multipurpose cooker-heater.

> When I have a working prototype I will share it with you.  I build with
> recycled from the bone yard when ever possible but am conflicted regarding
> the big industrial thing although I have certainly been a student of its
> tenets.  

You should see my steel scrap yard, all sorts of stuff, plate, I beam, 
tubing, farm equipment parts, springs, drive shafts, axles, torsion,
bars, bar stock and mystery stuff from commercial scrapyards.

> Concrete is conductive and not site specific requiring a lot of energy and
> high technology tooling to get at it so I am conflicted regarding its use
> though I must say I have built oodles of structures with steel reinforced
> concrete and also block.  The foamed stuff definitely is an improvement over
> solid for conductivity but I does it reflect radiant effectively?  Concrete

It is a chalky white block with very high R value; is OK fo load bearing 
walls with poured steel reinforced concrete beam at wall top. Best used 
a insulation in a concrete block cavity wall rather than as a structural 
element. It should reflect radiant heat OK, it will not absorb water or 
moisture/humidity/condensation, it will float in water! Simply add 
reflective material (foil backed foam insulation, maybe, for better 
reflectivity.

> is used as a thermal transmission mass in radiant floors as I have in my
> shop - very warm and conductive.  

How lucky you are.

> Glad to hear someone out there talking back!

Makes a big difference, I agree. Where in the USA are you located? Or 
Canada?

LL



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