[Stoves] Contextual v. global aspects of small-scale solid fuel combustion (Re: Crispin)

[Traveller]

Crispin:

This responds to another part of the same post by you (below).

I don't know if W/cm2 is a water boiling metric. I don't care for WBT in
the first place. I do remember something on Chris Adam's Biocoal website
about BTF - Boiling Time Factor. Is BTF affected by the W/cm2 or pot
size/shape in relation to the stove flame?

If so, of course these are relevant metrics, whether or not lab tests give
usable results. What one needs is a usable stove - or a usable fuel cycle
from the viewpoint of one who uses a stove or a kiln or a furnace; usable
tests have to correspond to that context. Otherwise, talk like "ah, we do
this and adjust for that and assume blah and presume bleech" is
pathological parading of punditry.

---

I do not only consider "the context element as an important facet of
performance (not just emissions)", I think context is everything for the
design and promotion of solid fuel stoves.

There is no "natural resource damage" except in local context. There is no
"pollution" except in local context. There is no "burden of disease" except
in local context.

The only question is, what is "local"?

Yes, deforestation for charcoal may occur 500-1,000 miles away but just
what difference does it make if some reforestation has occurred 50-1,000
miles in another direction? (I am not saying it makes no difference, just
that it is context-specific).

And so on with "pollution" and "burden of disease", depending on air
dispersion and long distance transport.

Which is why I don't think stove testing for rates of "fuel consumption"
and particular emissions should be done independent of context definition.
Where primary fuel is plentiful, ambient air quality is well below national
standards specific to the topography, and fuel emissions are quickly
ventilated, "usability" should rank above some % reduction targets.

Why, if I remember correctly, EPA has to work with state environmental
agencies for the implementation of its "New Source Performance Standards"
for residential wood heaters because of the variations in county-level air
pollution patterns.

Let me be blunt: "global climate" and "global burden of disease" are
spectacular blogal noises. They have no precise meaning, nor any theory
that can stand on empirically verifiable assumptions - just modeled
estimates based on model estimates based on.. yes, modeled estimates.

Would you say the Empire Promotion Agency is lording around poor people of
the world?

Nikhil

----------------------------


Message: 6
Date: Sat, 15 Oct 2016 13:44:37 +0000
From: Crispin Pemberton-Pigott <crispinpigott at outlook.com>
To: 'Stoves' <stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] A breath of fresh clean air: "Contextual Design
        and Promotion of Clean Biomass Stoves" (ESMAP - Indonesia)
Message-ID:
        <YTOPR01MB0235B11607D4AB5BC31D1EA7B1DE0 at YTOPR01MB0235.CANPRD
01.PROD.OUTLOOK.COM>

Content-Type: text/plain; charset="utf-8"

Dear Nikhil

Thanks for the compliments to the team. I appreciate that you specifically
mention the context element as being an important facet of performance (not
just emissions). If a fuel supply is limited to large-ish hard trees
(think: rural Zimbabwe) cooks are not willing to split them into strips for
feeding into a stove. And that is that. Stick-fed stoves are rejected and
they go back to consuming 12-15 kg of wood per day.

That is a contextual mismatch: fuel size.

In support of preferred fuel:  I found out something interesting this week
which is that the sub-40mm coal in Kyrgyzstan is quite a bit cheaper in
rural areas than 80mm coal. The 80 is preferred ?because it burns longer?
but that is only because they have far too much excess air so the only
solution is to decrease the surface to volume ratio. In that condition ?
high EA and low surface/volume ? it is not possible to burn it cleanly or
completely.

Another aspect of the context is that people strongly believe that coals
have  inherent gases contained in them that come out. ?This is a high CO
coal, that is a low CO coal.?  That sort of thing. Obviously the stove is
an important contributor to any CO produced. If we have a stove that
requires a certain size of fuel (a TLUD, for example) then we are forced to
change that part of the context, something that may not succeed.

In support of ignoring preferred fuel:  A success story in this regard is
the Sumba Island salt maker which requires that the fuel be cut short
enough to fit into the stove, not left sticking out. The effort is more,
but the fuel saving is 70% so overall the effort is reduced. This provides
an incentive to adopt the far more efficient evaporating system (fuel is
purchased). They enthusiastically agreed the system was, on balance, much
better and offered to do the additional cutting.

The context includes anything that affects the family or the performance.
The CSI project was a clear, firm step in the right direction. Contextual
testing can assist the early decision process about what to permit and
promote. I received today two new tests from Java, numbers 457 and 458.
They are cranking them out very consistently. One of the new metrics, the
heat flux (cooking power per sq cm of heater pot surface) is a reasonable
predictor of acceptance or rejection by the market. One model (we don?t
pick winners) was recently dropped by the vendors because people complained
it was underpowered. That was obvious enough from the contextual test which
showed a gap between the number people require (2.7 W/cm2) and the
candidate stove (less than 2). In other words, ?we told you so?.

Now W/cm2 is not a water boiling metric is it? Well, yes it is, indirectly.
If I know the heating ability, expressed on that basis, I can tell you how
long it will probably take to boil any quantity of water in any size of pot
in that particular stove, using only a calculator or a set of curves on a
chart. Experiments showed this is true to within a minute.  This metric
frees the tester from having to use a certain pot size or certain amount of
water. In other words, it is a metric suited to all contexts.

In the referenced CSI Indonesia Pilot the funding is being used up as the
supply channels are filled and sales continue. Apparently people like the
approved stoves.  Except the one we thought was underpowered? ?

Very cool.

Regards
Crispin
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