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Stovers,<br>
<br>
I appreciate Crispin's detailed message about corrections to the WBT
spreadsheet. I suspect that Crispin has it correct, but I leave it
to the technical experts about what is right or wrong in each cell
of the spreadsheet. (His full message is below, in case you missed
it.)<br>
<br>
There is one specific issue that needs discussion, so I have changed
the Subject line (so that we can stick to that single topic).
Crispin wrote:<br>
<blockquote type="cite">For stoves that produce a lot of charcoal,
it will give a large difference in the performance rating for
‘fuel consumption’, something much closer to its actual
consumption. ...<br>
</blockquote>
<blockquote type="cite">For TLUD pyrolysers that SFC number will
increase more than 200%. Don’t be shocked. It is now reporting
“Fuel Consumed”, not “Energy Theoretically Released turned into a
dry fuel mass equivalent”.</blockquote>
I agree with Crispin about "fuel" and "energy" consumptions being
different if charcoal is produced. Wood that is changed to
charcoal that is not burned is no longer wood, thus his suggested
corrections about <u>fuel </u>consumed are correct. <br>
<br>
But equally true is that the energy consumed should recognize that
charcoal is energy that still remains, and therefore should be
credited against the total energy of the fuel consumed. <br>
<br>
The question for the Stove Testing Community is whether what is
important is the fuel consumption or the energy consumption for a
specific task. <br>
<br>
Actually BOTH are important, and BOTH should be reported. <br>
<br>
Then the persons evaluating stoves can see both values and make
appropriate decisions, such as in the case of communities where wood
is in short supply and deforestation is a concern. For example: <br>
A. If the energy to accomplish the cooking task is the same, and
one stove does it with 1 kg of wood and another stove with 1.2 kg of
wood but leaving behind charcoal worth the energy in 0.2 kg of wood,
then the char-making stove consumed more wood (that is, more fuel).<br>
<br>
B. But if in that same situation one stove uses 1 kg of wood and
another uses (is able to use) 1.5 kg of agricultural residue (such
as stems or cobs) and leaves behind some appropriate quantity of
charcoal, then the first stove consumed 1 kg of wood and the
char-making stove consumed ZERO kg of wood (but it did use a fuel
that did not relate to the deforestation issue). <br>
<br>
Clearly, the fuel consumption (including knowing the type of fuel)
is important, but so is the energy consumption.<br>
<br>
By the way, the created charcoal STILL has its value, whether as a
fuel in a charcoal burning stove or as a soil amendment as biochar.<br>
<br>
Concerning the WBT as it currently is established, the WBT fails to
provide sufficient information to the evaluators of the stoves.
The full data exist in the detailed records of each test, but only a
selection is reported, and that selection is BIASED. Not
intentionally biased. Simply biased by not informing enough about
the realities of stoves, in this case about stoves that produce
charcoal. It is not only about the making of charcoal, it is also
about the ability of TLUDs (and some related stoves) to nicely
utilize non-woody biomass.<br>
<br>
This issue was of minor concern before TLUD stoves were seriously
considered to be viable for households. The WBT has links back many
decades and to early WBT spreadsheets in the mid 2000s. Even in
2010 there was minimal recognition of TLUDs and their char-making
characteristics, certainly not enough recognition for cause concern
in the WBT calculations. But things have changed, micro-gasifier
cookstoves were highly evident at the recent ETHOS meeting. And
there is no going back. <br>
<br>
Therefore, the WBT and other aspects of the evaluation of stoves
(including the Tier system that simplistically yields only a few
evaluative numbers) need to be brought up to date. <br>
<br>
Paul<br>
<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
<div class="moz-cite-prefix">On 2/26/2015 12:00 PM, Crispin
Pemberton-Pigott wrote:<br>
</div>
<blockquote
cite="mid:COL401-EAS1376C93E534CEC5162E39A5B1140@phx.gbl"
type="cite">For TLUD pyrolysers that SFC number will increase more
than 200%. Don’t be shocked. It is now reporting “Fuel Consumed”,
not “Energy Theoretically Released turned into a dry fuel mass
equivalent”.</blockquote>
<br>
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