<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Paul, List and ccs:</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>Well I haven’t heard a reason why my yesterday statement on only needing a single controller (limiting fuels to the non-oily variety) was incorrect. </div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>This is to hope we can have more discussion on this quite important point. </div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I am quite sure I saw a TLUD design a few years ago that used a single air control. Anyone able to help?</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I don’t know anything about Nathan Puffer’s work.</div><div class=""><br class=""></div><div class="">Ron</div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On Apr 29, 2017, at 9:33 PM, Paul Anderson <<a href="mailto:psanders@ilstu.edu" class="">psanders@ilstu.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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Ron,<br class="">
<br class="">
I disagree. You wrote:
<blockquote type="cite" class="">preferring to use one controller for both is
that the ratio of primary to secondary should always be the same </blockquote>
The point is that the ratio is NOT to always be the same. Even the
different packing of the fuel in to the TLUD can make primary air
(PA) flow more easily, creating more gases and needing a change in
secondary air (SA) to get optimal performance.<br class="">
<br class="">
Automobiles have sensors for all kinds of issues, with automated
adjustments. Just not practical yet for cookstoves that need to be
inexpensive. Bu who knows, someday solid biomass as initial fuel
could be pyrolyzed and have the gases combusted in very controlled
ways that would seem like Science Fiction if said today. I believe
that it will be justified for the woodgas/TLUD stoves, but not for
the old-hat ICS stoves, including rockets.<br class="">
<br class="">
Nathan Puffer''s work was not quantitatively evaluated. It was a
demonstration that made its point but was not in a way that could be
into large numbers of stoves at that time and still today. <br class="">
<br class="">
Paul<br class="">
<br class="">
<br class="">
<br class="">
<br class="">
<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 4/29/2017 9:46 PM, Ronal W. Larson
wrote:<br class="">
</div>
<blockquote cite="mid:4652859A-0EBA-4E3B-9F2B-5534ACCB2745@comcast.net" type="cite" class="">
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<div class="">Paul, cc Nathan and list</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>Thanks
for bringing up the two subjects of a) separately controlling
secondary air, and b) oily (mostly seed?) fuels.</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I
agree that we should be controlling secondary air, but I am
pretty sure that we should and can do this with the same
controller as for the primary air. Most TLUDs already can and
should control primary air, but make no effort to control the
secondary air. My reason for preferring to use one controller
for both is that the ratio of primary to secondary should always
be the same if we want (or can live with) a fixed ratio for
excess air. One controller is cheaper and is easier for the
cook. Anyone disagree?</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>On
the subject of using Jaropha seeds, I am pretty sure that we
would need a larger amount of “secondary” air than for non-oily
fuels, but that there still could be a single air controller
(just with a larger SA/PA ratio [ maybe goes from about 6:1 up
to 7:1 ??]. Note that these oils cannot combust as they pass
through the hot charcoal above the downward moving pyrolysis
front (no oxygen in that stream). But I presume the temperature
is enough for them to arrive above the char as quite a different
set of gases. So, I’d like to hear more about what Nathan
found. Any cite we can look up?</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I
agree with the rest of Paul’s comments. TLUDs are not yet a
mature technology - but it is growing up; it is not standing
still.</div>
<div class=""><br class="">
</div>
<div class="">Ron</div>
<div class=""><br class="">
</div>
<br class="">
<div class="">
<blockquote type="cite" class="">
<div class="">On Apr 29, 2017, at 8:14 AM, Paul Anderson <<a moz-do-not-send="true" href="mailto:psanders@ilstu.edu" class="">psanders@ilstu.edu</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div bgcolor="#FFFFFF" text="#000000" class=""> To
all, 29 April 2017 [This note
contains some new content and explanations for the
advancement of TLUD stoves.]<br class="">
<br class="">
1. Ron: I and probably some others have successfully
used dung as the input fuel into TLUDs. I am not
recommending dung, but if it is being burned, then a TLUD
is preferred for cleaner burning.<br class="">
<br class="">
2. AD: I agree with Ron that the TLUD stoves are better
with both light and hard (heavy) wood than direct burning
of them in any direct-burning (ICS) stove.<br class="">
<br class="">
3. Main point, to Neil and all: TLUDs are not burning
wood directly. TLUDs turn wood into gases. THEN the
gases are burned. So poplar, maple, maize cobs, dung,
etc. are ALL becoming gases first. THEN the burning of
those gases might be somewhat different (but not as much
as the direct burning of those diverse fuels). <br class="">
<br class="">
TLUD stoves are just arriving into their "young-adult
stage." In contrast: not infancy, not childhood, maybe
still "youth", but certainly not full maturity, and a long
way from the "old age" of the ICS "Inproved or
Inadequate" direct-burning cookstoves. This is because we
are still learning about better and better ways of mixing
the combustible gases with the incoming secondary air
(SA) (This is where the BURNING takes place to make the
heat that goes to the pot. TLUDs are DIRECTLY burning
GASES, not solid fuels. ) (Please see my
"Classification of Stove Technology and Fuels" documents
(1-page and 4-page versions) at
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://www.drtlud.com/2017/04/11/classification-stove-technologies-fuels/">http://www.drtlud.com/2017/04/11/classification-stove-technologies-fuels/</a>
)<br class="">
<br class="">
The <u class="">solid </u>wood and dung etc are an
intermediate stage of the fuel. Sort of a "storage"
stage. Then pyrolysis "transforms solids into gases plus
charcoal". The created gases are then burned SEPARATELY
(by centimeters and seconds, but certainly separately)
from where the gases were created. We do not have clear
terminology for this, in layman's terms. The closest
might be "gas burning stoves that make their own gases."
<br class="">
<br class="">
So, what development is happening in the early
"young-adult" stage? Control of primary air, learning
about solid "intermediate" fuels, and improving combustion
of the gases, as well as "new clothes" with sizes and
mateials. <br class="">
<br class="">
Consider this: We have known of FA (forced air or fan
assisted) TLUD stoves from the 1990s. And there has been
much progress. But NO TLUD on the market has SEPARATE
controls for "variable flows" of primary air (PA) and
secondary air (SA). THAT control is what will make the
difference regarding Neil's initial question that pointed
to differences in the initial fuels (and therefore
differences in the resultant gases and quantities of gases
that are being burned.) <br class="">
<br class="">
Note that TLUDs can be made with different flows of PA ans
SA by changing the sizes and number of holes. That is a
form of "tuning" the TLUD for a specific fuel. This
works great for one initial fuel, but only good but
acceptable with other fringe fuels. I am NOT referring to
that work as being "variable flows". I am referring to
when the user can change the flows, even during one batch
of fuel.<br class="">
<br class="">
There has been some researach (mostly unreported and set
aside) on variable control of primary and secondary air,
using fans. I have experimented several times. The
"million-dollar-grants" have had laboratory equipment with
controlled and measured separate air flows. Nathan Puffer
did it when we were looking at Jatropha SEEDS as a fuel.
Seeds give off additional gases from the vaporization (not
pyrolysis) of combustible vegetable oils (carbohydrates),
which are much more plentiful in seeds than in stems and
branches and leaves, thereby overwhelming the insufficient
supply of SA in a "regular" TLUD-FA. <br class="">
<br class="">
There is a good reason to not have separate control of PA
and SA. That reason is the user, the cook. To need to
"dial-in" the right flow of SA (assuming PA flow stays the
same) is, for the most part and for most non-scientist
cooks, an extra task that could easily be done
incorrectly. And there are the financial reasons of
increased cost and maintenance. <br class="">
<br class="">
But with "separate air-flow control" (not an established
term and NOT justifying an acronym like SAC, as in
TLUD-SAC), Neil or anyone could put many very different
initial fuels into a TLUD and have greater control of the
burning of the gases. <br class="">
<br class="">
More work is needed before TLUD stoves can reach their
full potential, while growing in "young-adulthood". Today
(2017), maybe 40% of what can be known about TLUD stoves
is now known (but not necessarily put into practice by
stove manufacturers). <br class="">
<br class="">
(This note is being placed at the EPosts section of my
website <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="http://www.drtlud.com/">www.drtlud.com</a> so
that it can be accessed continually instead of only one
time on the Stove Listserv.) <br class="">
<br class="">
Paul<br class="">
<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="http://www.drtlud.com/">www.drtlud.com</a></pre>
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