Dear Paul,<div><br></div><div>I like the two pot stove concept (both pots on top of the stove, not sunken, to accommodate different pots) because by decreasing heat losses (insulating the flow path of the hot gases) and by increasing heat transfer (using appropriately sized channel gaps under the pots and up around the second pot) the one fire can boil water in two medium sized pots (5 liters in each) at about the same time (around 30 minutes). The problem with a stove that exposes only the pot bottom above the fire is that a small percentage of the heat from the hot gases and goes into the pot (Shall we estimate 20% or so?). That includes radiation and conduction.</div>
<div><br></div><div>If the fire is 4 Kw or so there's a lot of useful heat in the hot gasses at a fairly high temperature to pass by the bottom and sides of the second pot inside the skirt with an adjustable channel gap of 8mm or so. </div>
<div><br></div><div>The problem is that we spoil the design by using a chimney unless we go to sunken pots. The chimney will take a disproportionate amount of hot gases away from the second pot unless the second pot is sunken. Then the hot gases can go up the channel gap inside the skirt before going down the outside of the skirt and exiting out the chimney. Like other chimney stoves the hot gases exiting should be below 200C as a goal: hot pots equal a colder chimney.</div>
<div><br></div><div>The added draft from a Rocket combustion chamber assists the hot gases to flow horizontally as does the draft created by the adjustable skirt around the second pot.</div><div><br></div><div>This design has surprisingly less PM which might be caused by additional scrubbing in the horizontal run?</div>
<div><br></div><div>All Best,</div><div><br></div><div>Dean<br><br><div class="gmail_quote">On Mon, Dec 31, 2012 at 8:06 PM, Paul Anderson <span dir="ltr"><<a href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>Crispin and Dale and all,<br>
<br>
The topic is the 2-pot stove structure (from two commercial
suppliers and for other sources). And NOT the heat creation unit
(which may or may not be built into the 2-pot stove structure).
<br>
<br>
For clarification of this, lets be sure that Dale's wood-fire
simulator (natural gas) is considered as equally appropriate as
the heat source as would be the Rocket devices or the TLUD
devices. <br>
<br>
Dale, this would be right up your alley. Heat transfer. <br>
<br>
And this shows how good stove testing could be done by someone who
is NOT a testing center. And Dale should NOT be expected to do
this work on his own time (unless he chooses to do so, with
approval by his employer who has the equipment.). <br>
<br>
Do we (Stover community including all of the GACC Partners and
GACC leadership) have a mechanism to get this task accomplished?
Perhaps some Stove Testing Center that gets a considerable chunk
of money from GACC could sub-contract Dale (or other appropriate
person) to get this job done for a relatively small cost.<br>
<br>
By the way, how much financial support is the GACC actually
putting into the hands of the Testing Centers? and with what
requirements? I assume that these are "transparent"
transactions already done or soon to be done or at least being
planned. <br>
<br>
And how can people like us Stovers with this very specific request
actually get this testing onto the agenda in general and/or at a
specific testing site? This is certainly "technology neutral"
and eligible to be financially supported.<br>
<br>
Imagine, if we had good data about these 2-pot "attachments",
there could be some very beneficial results ready for anyone to
implement.<br>
<br>
And are there already results in the hands of Prakti and Envirofit
and others that would be useful if known by others? <br>
<br>
Paul<br>
<pre cols="72">Paul S. Anderson, PhD aka "Dr TLUD"
Email: <a href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a> Skype: paultlud Phone: <a href="tel:%2B1-309-452-7072" value="+13094527072" target="_blank">+1-309-452-7072</a>
Website: <a href="http://www.drtlud.com" target="_blank">www.drtlud.com</a></pre>
On 12/31/2012 1:16 PM, Crispin Pemberton-Pigott wrote:<br>
</div>
<blockquote type="cite">
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dear
Dean<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks
for that clarification.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Paul’s
request for research into stove structures or types of
structures is interesting in that stoves are not usually
well classed as ‘structures’ but rather ‘models’ of some
prototypical stove design.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Paul,
I am not sure how you would design such research but it
surely would have to include a well vetted evaluation method
that gave results which could be used to interpret the
structure as being the cause an improvement (or not).<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Given
the 4 major influences: user, fuel, cooking vessel and the
stove, it would be worth spending some time to design the
experiment which would show that the stove (or structure of
the stove) was the contributing variable.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I
suspect that Dale Andreatta’s wood fire simulator is one
approach. If everyone recalls, he performed a number of heat
transfer efficiency tests using multiple thermocouples and a
standard gas-fuelled fire with a controlled gas flow rate.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Regards<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Crispin
saying bye-bye to the Old Year<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
</div>
</div>
<br>
<fieldset></fieldset>
<br>
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