<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Stovers,<br>
<br>
This message was held in the Moderator's box, so I will resend it
now.<br>
<pre class="moz-signature" cols="72">Paul S. Anderson, PhD aka "Dr TLUD"
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 4/14/2013 9:49 PM, Paul Anderson wrote:<br>
</div>
<blockquote cite="mid:516B6ABB.1030304@ilstu.edu" type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<div class="moz-cite-prefix">Dear Alex, Lanny, Dean and all,<br>
<br>
We are learning things about short flames and flame color that
should have been learn years ago!!! Thank you both (and
others) for getting this information to us. <br>
<br>
And Crispin has been telling us all along (and showing up with
his device at ETHOS etc) that a combustion analyzer is useful.
We (the generic we) need to get more serious. <br>
<br>
And Dean wrote:<br>
<blockquote type="cite"><br>
<div>>The very hot yellow/white flames easily make black
carbon.</div>
<div>>The less hot deeper yellow/red flames make less/no
black carbon.</div>
<br>
</blockquote>
Notes:<br>
1. Why isn't a combustion analyzer (as used for furnace work)
part of the standard equipment for stove testing, either for
formal protocol testing or for more simple testing at our
workshops and factories?<br>
<br>
2. Is this "turbulance" and "forced air" (flame height and
color) information telling us something about the "fan-jet" or
"vortex" stoves like Philips-FA and the Biolite and the RTI FA
stove tested in Kenya and others with STRONG forced air. The
Kenya study (presented by Mike Sage at GACC Forum) found that
the emissions were not as low as were hope for stoves with
fans. Is it possible that the extra turbulence of those stoves
is actually working against their lowering of emissions? <br>
<br>
To me, this is BIG and I hope that CSU and Tami and Aprovecho
and testing centers can check on this with modeling and
testing. (or is this basic knowledge in some specialist
fields? )<br>
<br>
Be sure to read Alex's message below if you have not already
done so.<br>
<br>
Paul <br>
<pre class="moz-signature" cols="72">Paul S. Anderson, PhD aka "Dr TLUD"
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>
On 4/14/2013 8:59 PM, Alex English wrote:<br>
</div>
<blockquote cite="mid:516B5F08.8070504@kingston.net" type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<div class="moz-cite-prefix">Yes, in the stoves world TLUDs with
fans are comparatively clean burning. I'm just saying it
doesn't necessarily follow that they are at their best when
their flame is shortest.<br>
<br>
Any burner will have a range of emissions including a sweet
spot where it performs best. There are lots of variables to
consider. Some require better instrumentation.<br>
For a TLUD with a fan, or a boiler with a fan, you can shorten
the flame with extra secondary air. As you know, if it isn't
needed for combustion then is robs heat, that may be needed
for optimum combustion. Yes long/tall flames can have sooty
tips. So there are potential trade offs. When I can see the
flame and my combustion analyser at the same time I have often
seen that a long flame has lower CO/CO2, less excess air and
higher heat transfer efficiency. Not enough air and it will
be even longer with poorer emissions. Flame colour is a clue,
its the numbers that inform. Better mixing from higher
pressure blowers/fans can shift the range of flame lengths
shorter. Stated another way, the optimum flame length is
unlikely the shortest.<br>
<br>
I'm being warmed by my ND pellet stove right now. After the
secondary air ports the flame travels horizontally through a
2.5 inch tube, 12" long. For this firing rate the sweet spot
is when the flame fingers are shooting out six inches past
the tube end. More secondary air shortens it back inside the
tube. Less secondary lengthens it and turns it more orange and
larger. CO/CO2 increases in both cases. There will be no
visual emissions from the chimney for any of these scenarios.
Real time PM and NOx numbers might enlighten this tale some.<br>
<br>
I've seen a large chip boiler cut its CO in half improve 4%
points of thermal efficiency just by closing some secondary
air ports. The flame lengthened by roughly 25%.<br>
<br>
Years ago when I was testing my Reed style fan TLUD on low
power. It had the smallest of flames but the flame didn't fill
the chamber cross section of the chamber below the pot. Some
of the pyrolysis products were sneeken past the flame and
condensing brown (not soot) on the pot. Less secondary air, a
larger flame, and perhaps a different geometry could have
helped. The problem went away at higher firing rates with a
bigger and somewhat taller flame.....<br>
....but I burnt the food and went hungry:(<br>
<br>
Alex<br>
<br>
<br>
<br>
<br>
On 14/04/2013 5:18 PM, Lanny Henson wrote:<br>
</div>
<blockquote cite="mid:2C9854DD8ECA439BBC06355936A7D1B3@main"
type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<meta name="GENERATOR" content="MSHTML 8.00.6001.19412">
<div><font size="4">A response from Alex English! made my day.</font></div>
<div><font size="4">Fan powered TLUDS have a nice short flame
height, are they not clean burning?</font></div>
<div><font size="4">Lanny</font></div>
<blockquote style="BORDER-LEFT: #000000 2px solid;
PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px;
MARGIN-RIGHT: 0px">
<div style="FONT: 10pt arial">----- Original Message ----- </div>
<div style="FONT: 10pt arial; BACKGROUND: #e4e4e4;
font-color: black"><b>From:</b> <a moz-do-not-send="true"
title="english@kingston.net"
href="mailto:english@kingston.net">Alex English</a> </div>
<div style="FONT: 10pt arial"><b>To:</b> <a
moz-do-not-send="true"
title="stoves@lists.bioenergylists.org"
href="mailto:stoves@lists.bioenergylists.org">Discussion
of biomass cooking stoves</a> </div>
<div style="FONT: 10pt arial"><b>Sent:</b> Sunday, April 14,
2013 2:25 PM</div>
<div style="FONT: 10pt arial"><b>Subject:</b> Re: [Stoves]
Airflow For Biomass Fired Appliances- Natural Draft Stoves</div>
<div><br>
</div>
<div class="moz-cite-prefix">Lanny,<br>
I understand the comment below but I think flame height
can be shortened with excessive excess air. The lowest
emissions CO/CO2 and highest temperatures, at some power
levels, in appliances that I have tested has often been
when there is a significantly taller tail of flame. <br>
<br>
However, don't believe all tall tails :)<br>
Alex<br>
</div>
</blockquote>
</blockquote>
<br>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a>
to UNSUBSCRIBE or Change your List Settings use the web page
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a>
for more Biomass Cooking Stoves, News and Information see our web site:
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://stoves.bioenergylists.org/">http://stoves.bioenergylists.org/</a>
</pre>
</blockquote>
<br>
</blockquote>
<br>
</body>
</html>