[Stoves] Analysis of a two-stove cooking system

[ajheggie at gmail.com]

[Default] On Sat, 28 Nov 2015 15:42:46 -0700,"Ronal W. Larson"
<rongretlarson at comcast.net> wrote:

>	4.    A different reason for objecting to the computations is that way too much charcoal was thrown way (1.5 MJ worth) as valueless (and any fines would have great value as biochar anyway - and so should be considered). 

Just a quick comment, I too found this an unreasonable assumption, not
only did I not find the results of a TLUD burn to contain discernable
fines or ash (unless there was some recycling of the char into a
second burn) but also char in ash still offers the opportunity to
provide minerals and soil improvement *if* that is the reason for
wanting to produce char in the first place.

BTW you and I did experiment with adding fuel to a tall (1 metre)
forced draught TLUD burn in around 2002 though when you were there I
suspect we only added small pieces of coal. I never did follow this
through to conclusion but my thoughts were, assuming the added fuel
was fine and dry, that it would continue to work until the offgas fell
below about 400C as there would be some endothermy in raising the new
material to pyrolysis temperature after which it should self sustain,
though the char from the added material would be higher volatiles that
than which the pyrolysis front had passed through.

Art I concur with your approach, I found the Anila to be a pretty poor
stove from a usability point of view and the extra effort to produce
the char in the outer section not worthwhile compared with a simple
TLUD.

Finally fuel conversion efficiency, whilst valuable from a
conservation point of view, is seldom what the market dictates, if the
market wants a bigger car it will pay for the extra fuel, if it wants
to produce char it will pay that cost too (not that I think TLUD is
necessarily more costly in fuel because the lower pollution benefits
offer the most value in my opinion).

AJH