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<div class="moz-cite-prefix">Frank and all Stovers,<br>
<br>
When combustible gases are produced (and CO is produced in the
charcoal stoves), the air for combusting those gases would be the
secondary air.<br>
<br>
In typical charcoal stoves that air comes in over the top rim of
the stoves, and is poorly mixed, and the result is massive CO into
the room. And very little air can enter when a pot is in place,
especially if there is also a pot skirt.<br>
<br>
Work on introducing secondary air via specific openings can be
seen some nice work done by GIZ:<br>
<br>
<a class="moz-txt-link-freetext" href="https://energypedia.info/wiki/File:ECLAIR_Benin_stove-factsheet_eng.pdf">https://energypedia.info/wiki/File:ECLAIR_Benin_stove-factsheet_eng.pdf</a>
<br>
<br>
More work needs to be done on this topic.<br>
<br>
About reflective shinny surfaces, does anyone have any info that
is related to stoves comparing metals (different status of shinny)
and clay/mud/ceramic? For example, how much more heat-to-the-pot
is gained by using metal versus ceramic, and is that difference
sufficient to justify (in part?) the extra cost of metal? High
mass ceramic/clay takes up more heat than does the metal, but is
it really significantly more?<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>
On 9/16/2013 1:00 PM, Frank Shields wrote:<br>
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<div class="WordSection1">
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Stovers
and Paul Anderson, <o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Since
good char burns with little smoke it seems there could be
some design improvements from the stove in Paul’s
attachment:<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoListParagraph"
style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span
style="mso-list:Ignore">1)<span style="font:7.0pt
"Times New Roman""> </span></span></span></b><!--[endif]--><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">We
can use shinny surfaces, perhaps like a bowl under the
charcoal, to reflect the heat up to the pot.<o:p></o:p></span></b></p>
<p class="MsoListParagraph"
style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span
style="mso-list:Ignore">2)<span style="font:7.0pt
"Times New Roman""> </span></span></span></b><!--[endif]--><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Best
to heat a pot we need a blast of hot air directed at the
pot -that is not available with radiant heat. I believe to
get char to burn we need the same; a blast of air directed
at the char. Perhaps because when the carbon goes to CO or
CO2 it releases enough heat to start another reaction IF
there is oxygen stuck to that carbon allowing a reaction
to take place. If not the heat dissipates and does little.
<o:p></o:p></span></b></p>
<p class="MsoListParagraph"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoListParagraph"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Wondering:
if a basket of char fitted with a plate at the bottom set
on a spring pressing char up against a top grate. The
container sealed such that primary air being drawn is
directed through a pipe blasting 2cm from the top of the
char bed (vertical pipe through the center of the char).
The reflective surface directing heat produced to the
pot. Something like that?<o:p></o:p></span></b></p>
<p class="MsoListParagraph"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoListParagraph"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Also;
For char stoves is there ever a secondary? <o:p></o:p></span></b></p>
<p class="MsoListParagraph"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Frank<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Frank
Shields<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Control
Laboratories; Inc.<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D">42
Hangar Way<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Watsonville,
CA 95076<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D">(831)
724-5422 tel<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D">(831)
724-3188 fax<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D"><a class="moz-txt-link-abbreviated" href="mailto:frank@biocharlab.com">frank@biocharlab.com</a><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-family:"Calibri","sans-serif";color:#1F497D"><a class="moz-txt-link-abbreviated" href="http://www.controllabs.com">www.controllabs.com</a><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></b></p>
<div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">
Stoves [<a class="moz-txt-link-freetext" href="mailto:stoves-bounces@lists.bioenergylists.org">mailto:stoves-bounces@lists.bioenergylists.org</a>]
<b>On Behalf Of </b>Paul Anderson<br>
<b>Sent:</b> Monday, September 16, 2013 7:24 AM<br>
<b>To:</b> Discussion of biomass cooking stoves; James
S. Schoner<br>
<b>Subject:</b> [Stoves] Amount of charcoal for
simmering<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Stovers, (this will also be a "post" at
my <a moz-do-not-send="true" href="http://www.drtlud.com">www.drtlud.com</a>
website, BUT all replies and discussions should be directed
via the Stoves Listserv. Dr TLUD does NOT carry on separate
discussions via comments to his website.)<br>
<br>
I am looking for a calculated answer that could give
guidelines about the sizes of charcoal-burning stoves,
referring to how much charcoal must be consumed for the
cooking tasks.<br>
<br>
Question: How much charcoal is needed (per minute, or per
hour, or ??) to maintain a pot (5 liters?) of already-boiling
water at the simmer temperature of about 96 deg C?<br>
<br>
So many variables, but the replies can state whatever "givens"
or assumptions you wish to make, such as:<br>
<br>
1. Heat transfer efficiency of the stove-pot
configuration: Is 30% about typical? And does that vary
between clay-mud charcoal stoves vs metal charcoal stoves?
Please specify, if your response takes that into account.<br>
<br>
Reference: See <a moz-do-not-send="true"
href="http://search.mywebsearch.com/mywebsearch/redirect.jhtml?searchfor=heat+transfer+efficiency+charcoal+stoves&cb=XQ&p2=%5EXQ%5Exdm002%5ES03729%5Eus&qid=499b92ca6697461da7047b820086bd7d&n=77DE8857&ptb=F7EBB78D-F7A7-4077-B858-0D10F0C7CB0E&si=COjP4cCp0rMCFao7MgodRQUALQ&pg=GGmain&action=pick&ss=sub&pn=1&st=hp&qs=&pr=GG&tpr=hpsb&redirect=mPWsrdz9heamc8iHEhldEVRIIbml7k2%2FvmB8U5crkZmbOTdLROAzdl%2F4ZQYYskvUwjkty6%2BVZ%2BNQiIr863cMN8jdRHpxuJvwsN2u6HPpdnPNB%2BBymTTjJMbwcgCi5H8Q&ord=1&ct=AR&"
target="_blank">Experimental study for improving energy <b>efficiency</b>
of <b>charcoal stove</b> </a><br>
<a moz-do-not-send="true"
href="http://nopr.niscair.res.in/bitstream/123456789/3794/1/JSIR%2068%285%29%20412-416.pdf">http://nopr.niscair.res.in/bitstream/123456789/3794/1/JSIR%2068(5)%20412-416.pdf</a><br>
with reported efficiencies between 21% and 62%.<br>
<br>
2. Still air, no wind.<br>
<br>
3. Comments on types of pots (Stainless vs aluminum vs
other).<br>
<br>
4. Lid or no lid. Probably no lid because so much testing
is done with no lid on pot.<br>
<br>
5. Ambient temperature: probably 22 to 27 deg C.<br>
<br>
6. Any other variables.?<br>
<br>
Comments: The question arises because the TLUD stoves (and
any other charcoal producing stoves) can be a convenient and
low cost source of charcoal for a household. That household
has some cooking needs for LOW heat (simmer-type), and a
charcoal-burning stove.<br>
<br>
Example from the world of stove testing: a pot with 5 liters
brought to boil can be placed onto a charcoal stove for the
remaining 45 minutes of the standard water boiling test
(WBT). The charcoal could be already red-hot, having been
placed in the charcoal stove directly from the TLUD stove that
made the charcoal. How much charcoal is needed for that
simmering task?<br>
<br>
When we know the amount of charcoal, we can calculate
backwards to determine how much raw fuel was needed to make
that charcoal. (That amount of raw fuel is approximately 5 X
of the charcoal weight.) Example: 100 g of char is
produced from 500 g of woody biomass. <br>
<br>
Therefore, about 70% of the energy content of the raw fuel
would be available for INITIALLY putting heat into the pot. I
think we should assume better than 40% heat transfer
efficiency because that is the target for Tier 4 stoves and
can be achieved by gas-burning stoves. 40% of 70% is 28%,
so round it to 30%. And 30% of the energy content of the
raw fuel is how much? 1 kg of wood has 16 MJ, so 500 g has
8 MJ, and 30% would be 2.4 MJ. <br>
<br>
Somebody please complete the calculations: <br>
<br>
A. 2.4 MJ will raise 5 liters (5000 g or ml) of water how
many degrees?<br>
<br>
B. How many g or ml of water can be brought to 100 C if
starting temp of water is 20 C?<br>
<br>
In the end, I hope we have some understanding about the amount
of raw fuel and resultant charcoal needed to accomplish the
WBT with minimal waste.<br>
<br>
Paul<br>
<br>
<o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Doc / Dr TLUD / Prof. Paul S. Anderson, PhD <o:p></o:p></pre>
<pre>Email: <a moz-do-not-send="true" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a> <o:p></o:p></pre>
<pre>Skype: paultlud Phone: +1-309-452-7072<o:p></o:p></pre>
<pre>Website: <a moz-do-not-send="true" href="http://www.drtlud.com">www.drtlud.com</a><o:p></o:p></pre>
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