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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>You don’t seem to understand how these things work.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>In operation, the two chimneys glow red-hot. The radiant
heat evaporates kerosene from the glass-fibre wick, and the hot vapours rise
and are mixed with air coming in through the holes – which of course is
pre-heated. Combustion take place in the annulus. As the mixture
rises, you even get some secondary air combustion effects quite high in the
chimney – under some conditions you can see blue flames going inwards
from the holes.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>When first lit, the chimney pieces are still cold, and you get a
rather dirty diffusion flame until the radiant-heat evaporation of the kerosene
occurs. The reverse can happen on switching off – the chimney
pieces are still hot and kerosene continues to evaporate from the retracted
wick and gives a “tracer flame” which takes some time to go out.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The thermal loss by radiation is what reduces the efficiency of
this design when used as a cookstove to the order of 30-35%. Of course, in a
heater this is no loss. In the design you have to be careful to shield
the fuel tank from heating by radiation and conduction; in some designs of
cheap cookstoves, this feature is ignored, and if used for more than about 30
minutes the fuel can heat to above its flash point. When that happens,
even knocking the stove can lead to catastrophic fires – we measured one
burning at over 1MW! It can lead to indoor air temperatures exceeding 400 deg C
within a minute.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The chimney pieces are quite thin to reduce their thermal mass
and so reduce the time it takes to heat them up when starting the appliance –
or cooling down when switching off.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Prof Philip Lloyd</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Energy Institute</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Cape Peninsula University of Technology</span><span
style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>PO Box 652, Cape Town 8000</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Tel:021 460 4216</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Fax:021 460 3828</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Cell: 083 441 5247</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Stoves
[mailto:stoves-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Julien
Winter<br>
<b>Sent:</b> 08 April 2014 01:48<br>
<b>To:</b> Discussion of biomass cooking stoves<br>
<b>Subject:</b> [Stoves] TLUD Syngas Flame and the Red-Hot Chimney in a
Kerosene Heater.<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>Hello stovers;<o:p></o:p></p>
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<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>I took my Kero-Sun Radiant 10 apart. There are
some photographs of the inner and outer chimneys in the attached pdf.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>The inner chimney as baffles at the bottom and is enclosed,
with perforations at the top.<o:p></o:p></p>
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<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>For sport, I put the inner chimney, and then the inner
chimney nested in the outer chimney on top of a 7.5 cm diameter natural draft
TLUD. As we might expect, it created resistance to exhaust gas flow, that
reduced the secondary uptake, and caused the TLUD to emit a small amount of
visible smoke. I did this in daylight, so I don't know if any of
the chimney assembly became red hot.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>In order to investigate this properly, I would have to
destroy the chimneys by breaking off the baffles, and expanding the diameter of
the perforations in the chimney walls --- and I am not prepared to do
that. What is needed is to find a kerosene heater wreckers yard to
scavenge bits.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>Thus, it is still an open question (for me anyway) if
something like the chimneys in kerosene heaters, or a type of catalytic
converter, can reduce soot production from natural draft TLUDs.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Cheers,<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>Julien<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><br>
-- <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>Julien Winter<br>
Cobourg, ON, CANADA<o:p></o:p></p>
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