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Stovers,<br>
<br>
Sorry for my silence, but I have had 4+ days on other pressing
issues. I am STILL trying to catch up with messages since 16 Dec..
<br>
<br>
I thank Andrew for his mostly supportive comments about "TLUD" as a
name with specific meaning. <br>
<br>
I have some serious questions about the Chinese research of a TLUD
stove with pellets, referecned in Crispin's message:<br>
<br>
<div class="moz-cite-prefix">On 12/16/2017 2:16 AM, Crispin
Pemberton-Pigott wrote:<br>
</div>
<blockquote type="cite"
cite="mid:MWHPR22MB078418DA198F1C6FF603DC51B1080@MWHPR22MB0784.namprd22.prod.outlook.com">
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<div class="WordSection1">
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Dear
Friends<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">The
paper: </span> <a
href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fijabe.org%2Findex.php%2Fijabe%2Farticle%2FviewFile%2F2963%2Fpdf&data=02%7C01%7C%7C2ce737e1fcb04e81977608d5441d74c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636489815661627525&sdata=MaQEhXYbbVfEhPWeoSCl2MFqz6eRTyM3HrldZUtj2KE%3D&reserved=0"
moz-do-not-send="true">https://ijabe.org/index.php/ijabe/article/viewFile/2963/pdf</a>
<span class="apple-tab-span"></span><i>Effects of biomass
pellet composition on the thermal and emissions performances
of a TLUD cooking stove</i> is a TLUD pellet-fueled cooking
stove.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span class="apple-tab-span">Ron commented:
“</span>This achieves a record low for TLUDs of 10%
efficiency - whereas Julien, Kirk, Paul and others are at 40%
and more.” <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The paper reports the fuel efficiency (the
energy available in the fuel fed into the stove v.s. cooking
energy the stove delivers to the pot). The numbers reported by
the sources, if using the WBT, are the heat transfer
efficiency values (actually, an approximation of it – it is
not exact). These two efficiency metrics are incompatible
unless the system produces no residual char, which would be
unusual for a solid fuel stove.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards<o:p></o:p></p>
<p class="MsoNormal">Crispin<o:p></o:p></p>
</div>
</blockquote>
1. About the TLUD name: Interesting that Crispin and the Chinese
authors all say "TLUD" as if they think that such a name actually
does denote a quite specific type of cookstove technology. Well,
that is good. We do not need to be thinking of other UD-TL stoves
when we read the name "TLUD". <br>
<br>
2. Three times the publication says: "a typical Chinese
household biomass stove without a chimney" was selected [was
tested} and fueled with different kinds of biomass pellet fuels. I
was not aware that a TLUD stove was "a <font size="+1"><b><u>typical
</u></b></font>Chinese household biomass stove" or that it is "a
popular TLUD Chinese biomass stove" (Section 4. Conclusions).
Maybe someone could better inform us of numbers and models, etc.
Todd Albi sells Chinese-made TLUDs in America, so I assume some of
those stoves are sold in China also. But the one in the photo is
not one of the models sold by Silverfire.us. I would love to
have a TLUD success story from China. But I am a bit skeptical
about it being "typical" there. And are there any test results
(from Jim Jetter at EPA or Aprovecho or other not-in-China testing
centers) of the stove in the cited study? Can anyone send more
photos?<br>
<br>
3. I struggle with equations and calculations (Section 2.5.1), so I
cannot make comparative comments about the Chinese methods vs.
elsewhere. I might be wrong, but I do not see any inclusion of the
charcoal that came from the TLUD at the end. That leads to some
questions:<br>
A. Was there no charcoal to measure? If they run a TLUD as a
charcoal burner stove after the pyrolysis stage is finished (and
until all the charcoal was consumed???), that would be very
inefficient and pull down the % efficiency calculation. <br>
<br>
B. Or was the char just discarded as "no longer being pellet fuel"
and therefore judged to have been "fuel used"???<br>
<br>
4. Section 3.2.1 says
<blockquote type="cite">
<div style="left: 501.353px; top: 1242.36px; font-size: 17.076px;
font-family: serif; transform: scaleX(1.00313);">As shown in
Figure 4, at the beginning of the test, the water temperature in
the pot increased slowly. This stems from the fact that fuel
with a high moisture content often requires additional energy to
vaporize the fuel moisture resulting in a low net energy
release rate. During this fuel-drying phase the emissions can be
high.</div>
</blockquote>
Interesting, this reported "fuel-drying phase"..."at the beginning
of the test" is not like TLUD stoves that I know, where fuel drying
occurs little by little as the MPF (decending pyrolysis zone (AJH is
correct)) progresses. A drying phase at the beginning of a fire
would occur when the fire is at the bottom and the initial rising
heat is partially used to dry the fuel pile above the hot zone.
Perhaps someone can explain what happens in the authors' usage of
their TLUD stove.<br>
<br>
5. The photo of the stove in operation shows what appears to me to
be a very high-power flame. And the Conclusions recommend
<blockquote type="cite"> Further study should be done with different
stoves testing a diverse range of fuels [to] try discover which
fuel attributes and which stove architectures combine to deliver
superior performance. <br>
</blockquote>
So the researchers acknowledge that "stove architectures" can be
adjusted, implying that there was not an attempt to have the
existing, typical, popular stove adjusted to give its best
performance with three types of pellet fuels that were not WOOD
pellets (not included in the research) but which might be the type
of pellets for which the stove was optimized (if ever optimized?).<br>
<br>
6. Finally, in the last paragraph before the conclusions, we read:<br>
<blockquote type="cite">
<div style="left: 501.353px; top: 191.746px; font-size: 17.076px;
font-family: serif; transform: scaleX(1.00019);">The WBT
protocol, Version 4, specifies a different stove operating
sequence [than the Chinese testing]. The EF (PMi) s dramatically
different because of the combined effects of the very different
test sequence and calculation method. The test sequence changes
the combustion efficiency and combustion conditions. With its
different fire management sequence, the combustion temperature,
oxygen supply, mixing states and the differences in fuel
evolution result in an EF (PM) that is strongly at variance
with the test sequence employed in this work.</div>
</blockquote>
Well, that says much. Comparing apples and oranges. Perhaps others
who are more into the details of testing might want to try to sort
out what are the different stove operating sequences. Perhaps BOTH
are good. Or only one. or neither? But until someone sorts
that out, the fuel efficiency numbers cannot be compared with
numbers from other testing systems.<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>
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