[Stoves] secondary combustion and firewood

[George Riegg Gambia]

hi all

i want my cake and eat it.
i've stumbled into this situation simply because i work for a paper recycling charity here and i absolutely hate waste of any kind - be it resources, time, people, within the environment, wherever.
i have now put together a project proposal ruthlessly trying to tap into the global carbon offset scramble, starting off with a 3 months research period for evaluation and then rolling the programme out. our projected annual production will be 150 tons of paper/sawdust bricks to be used together with more efficient stoves.  the gambia is a small country - 1.5 mil people - and we do intend to go into the urban areas with alternative fuel production.
however, no matter how many compressed bricks we produce from whatever materials, we can't be blind to the fact that firewood will, for the time being, be the predominant household cooking fuel.

and i find myself in front of a big stumbling block which 5 months looking here and around members websites - and elsewhere - i can't get to grabs with.

very early in my research i came accross crispin's company. his years of research on paper/sawdust briquetting was invaluable to me and he actually produces the machinery to do the job as well. from his briquettes i arrived at his vesto stove - they fit like hand and glove. from his explanations and pix it's easy enough to understand the principles of secondary combustion and the benefits of it - both for the community and the environment. with that as my basis i started looking around, have come accross many a great innovation using different methods, fuels, stoves, approaches....

looking at the principle of secondary combustion the preheating of the secondary gases seems to be of the utmost importance. in all the stoves i have seen, fuel-feed seems to happen to a central primary combustion basket from the top and air-feed from the sides further down with pre-heating taking place between the fuel basket and the outer stove skin. since in my opinion a successful sustainable programme has to mean that the stoves are affordable, air-feed should be unassisted - again the vesto stove fulfills this criteria.

in crispins brochure he recommends a max length of fuel of 20 cm for the vesto. here our average length of firewood is between 40 and 60 cm and we are all aware that no matter how much a new stove would save on wood-fetching labour, money or emissions, if the wood the housewife gets doesnt fit the stove it's not good.
old customs die hard.

is there a solution to this conundrum i haven't found yet?

any help would be greatly appreciated
thanks
george
prsp
the gambia