[Stoves] Analysis of a two-stove cooking system

[Ronal W. Larson]

Andrew cc list

	See inserts below.


> On Nov 29, 2015, at 3:38 AM, ajheggie at gmail.com wrote:
> 
> [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.

	[RWL1:   I only vaguely that visit, but am pretty sure we were testing added fuel - not extra fuel to start off (to increase the TDR - so as to have the highest possible power level at the beginning.  

	RWL2:  A new/different?? idea (also never tested personally) is to add a very lightweight (wood shavings?. pine needles?) fuel on top of the regular normal, more dense base fuel.    The secondary air supply should probably be near the partition level, with the expectation this upper layer of fuel will be combusted, not pyrolyzed    Anyone ever tried this two-level fuel approach?

> 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.
	[RWL3:  Has anyone come to the opposite conclusion?  The advantage of being able to put junk material in a closed container can be a part of a 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).
	
	[RWL2:   Not sure whether “pollution” means CO2,  PAHs, CO, particulates or what - but all are important.   And one gets soil and atmospheric improvement at no cost if the char is placed in soil.

	Andrew - anything special happening near you re tomorrow’s COP21 opening?  I attended a Denver Climate “March” today.

Ron

> 
> AJH
> 
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