<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";
color:black;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";
color:black;}
span.ssens
{mso-style-name:ssens;}
span.EmailStyle21
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.EmailStyle22
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle23
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle24
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle27
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Ron,<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 this case I was looking at more a broad view of fuel/task ratio. That is; Adjusting TDR by adjusting fuel to improve Fuel / task efficiency. But when looking just in the Stoves box a stove in the ‘sweet zone’ and being able to move the pot to a cooler place is also acceptable for a TDR. I now agree this is not the place but once we get a plan we need air quality, task quality, safety and many other conditions to be attached. <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'>So I back petal a little. <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'>Thanks<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'>Frank<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><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Thanks <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Frank Shields<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>BioChar Division<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Control Laboratories, Inc. <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>42 Hangar Way<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Watsonville, CE 95076<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>(831) 724-5422 tel<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>(81) 724-3188 fax<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><a href="mailto:frank@biocharlab.com"><span style='color:blue'>frank@biocharlab.com</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>www.controllabs.com<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><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><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><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> rongretlarson@comcast.net [mailto:rongretlarson@comcast.net] <br><b>Sent:</b> Monday, May 06, 2013 10:30 AM<br><b>To:</b> Discussion of biomass cooking stoves; Frank Shields<br><b>Subject:</b> Re: [Stoves] Stove Definition - controllability<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Frank and list<br><br>see below<o:p></o:p></span></p><div class=MsoNormal align=center style='text-align:center'><span style='font-family:"Arial","sans-serif"'><hr size=2 width="100%" align=center id=zwchr></span></div><p class=MsoNormal><b><span style='font-family:"Arial","sans-serif"'>From: </span></b><span style='font-family:"Arial","sans-serif"'>"Frank Shields" <<a href="mailto:frank@compostlab.com">frank@compostlab.com</a>><br><b>To: </b>"Discussion of biomass cooking stoves" <<a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a>><br><b>Sent: </b>Monday, May 6, 2013 10:10:15 AM<br><b>Subject: </b>Re: [Stoves] Stove Definition - controllability<br><br><br><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Stovers,</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>It seems there may be many ways to adjust the TDR. Using thicker pots, more insulation in the stove body, pot location and change etc. But in our reference I think we want to adjust the power impute ( fuel) so lower power we save fuel. </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <b>[RWL1: for TLUDs and other char-making stoves (batch stoves), we need to replace your ""power inputs (fuel)" with "power and energy inputs (fuel and air)". Next sentence - replace "materials" with "materials and/or air flow."]</b></span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This while the other methods keep the stove power maintained in the ‘sweet zone’ and adjust the location or materials but maintains high fuel consumption. I suggest an interpretation ratio might be maximum heat with good PAM readings to lower heat (fuel) with good PAM readings. </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <b>[RWL2: What is "PAM"? I presume maybe "particulates and monoxide"? My belief is that the four GACC emissions groupings are based on an average (maybe worst case? ) of some kind for various tests. If not the right way, we should say so. I have not looked at this enough to suggest an alternative, but I think your suggestion may be too narrow, unless you are sure this is the best way to protect human health, while not treating any stove type preferentially. Our issue and emphasis now should be on the GACC/I WA procedures - since so much effort has gone into them. Ron]</b></span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Frank</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Thanks </span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Frank Shields</span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>BioChar Division</span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Control Laboratories, Inc. </span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>42 Hangar Way</span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Watsonville, CE 95076</span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>(831) 724-5422 tel</span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>(81) 724-3188 fax</span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><a href="mailto:frank@biocharlab.com" target="_blank">frank@biocharlab.com</a></span><o:p></o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://www.controllabs.com">www.controllabs.com</a></span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> Stoves [<a href="mailto:stoves-bounces@lists.bioenergylists.org">mailto:stoves-bounces@lists.bioenergylists.org</a>] <b>On Behalf Of </b>Kevin<br><b>Sent:</b> Sunday, May 05, 2013 10:55 PM<br><b>To:</b> Discussion of biomass cooking stoves<br><b>Subject:</b> Re: [Stoves] Stove Definition - controllability</span><o:p></o:p></p></div></div><p class=MsoNormal> <o:p></o:p></p><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Dear Crispin</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Thanks for your comprehensive reply! I fully agree with all your comments, except for those which I extract as follows:</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p></div><div><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>1</span></strong><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>: </span></em><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span></em><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Also, the maximum heat input rate to the pot, i.e. "pot power", will have an effect on the required TDR.</span></em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'> </span><o:p></o:p></p><div><p class=MsoNormal><em><span lang=EN-CA style='color:windowtext'> </span></em><em><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Aha. Well this is not the case. The definition of the turn down is not the firepower, it is the heat gained by the pot. Interestingly, there are major outcomes from this conceptual difference. The WBT’s classically observed the fire but people do not cook with the heat of the fire, only the part which gets to the pot. As you have observed, the heat transfer efficiency varies with firepower and therefore stating a minimum TDR does not really say anything about the firepower involved, only the cooking power.</span></em><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'># What I was getting at here is if the stove was "high powered" to rate well in a "Water Boiling Test", it may be "over-powered" for what is needed to cook most foods. </span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>Are we "on the same page" now? :-)</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>2:</span></strong><span lang=EN-CA style='font-family:"Arial","sans-serif"'> <em><span style='font-family:"Arial","sans-serif"'> > </span></em></span><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>1: For most efficient cooking, and to reflect most common cooking practises, the pot should be covered.</span></em><o:p></o:p></p><p class=MsoNormal><em><b><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>That is not relevant to the TDR, though an important programmatic consideration.</span></b></em><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'># Consider two WBT Tests... one with a cover, and one with no cover, on the same stove. The same amount of "power to the pot" will show a higher "pot power" when covered, than when not covered, because of extra losses from the uncovered pot. If the stove was subsequently modified so that "covered pot" had the same "time to boil", its actual "heat to the pot" would be less than the "heat to the uncovered pot." Thus, the covered pot would be less likely to be "overpowered, in relation to the actual energy required for maximum cooking. Accordingly, the covered pot would require a lower turn-down ratio than would an uncovered pot, in that most cooking is done with a covered pot.</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>Does that make sense?</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>3:</span></strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'> ></span><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>3: .A stove heating a covered pot will require a larger TDR than a stove heating an open top pot with no cover.</span></em><o:p></o:p></p><div><p class=MsoNormal><em><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This is debatable and so far I am not convinced</span></em><strong><i><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>.</span></i></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'># I can see </span></strong><strong><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span></strong><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>why you found it "debateable" and why you were "unconvinced"... I think I had my conclusions reversed, as per explanation in 2: above. I presently feel the correct statement should be:</span></strong><o:p></o:p></p><p class=MsoNormal><strong><i><span lang=EN-CA style='font-family:"Arial","sans-serif"'>"A stove heating a covered pot will require a LOWER TDR than a stove heating an open top pot with no cover."</span></i></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif"'>Does that make better sense now?</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif"'>4: <em><span style='font-family:"Arial","sans-serif"'>></span></em></span><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>4: A stove with "high pot power input" will require a larger TDR than a pot with a lower "pot power input."</span></em><o:p></o:p></p><div><p class=MsoNormal><em><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This is a no-no because to embed the concept into a Standard means interfering with preferences of the manufacturer and customer. The deal is between the buyer and the provider, not the regulator. The regulations are there to protect the customer and to label a product as being able to perform certain things, such as to deliver a locally acceptable water boiling rate in a pot with a diameter of 150mm or 300mm (as per the label on the product). The customer knows full well that a stove that cooks ‘well’ with a 250mm diameter pot will have problems getting the same cooking experience out of a 400mm diameter pot. What is not permissible is to have a manufacturer claim that the product ‘cooks well’ with a 400 when a test of the heat transfer rate shows it will only do so if the pot is about 250 in diameter.</span></em><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'># I think my >4 statement above is correct, based on the fact that 'high powered" stove will have a greater excess of power above that required for normal "maximum required cooking power." The presumption is that "high power is good" for fast boiling, but that it is bad because of providing excess power above that required for maximum cooking effect. In your note to Paul and Lanny on 4 May, it appears that: </span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>* 2 watts/square cm. is good for a maximum water boiling requirement</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>* 1 watt/square cm is the "normally required maximum power input, for actually cooking"</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>* 1/2 watt/square cm is an acceptably "low cooking heat"</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>This being the case, why not simply do the test with whatever pot diameter is chosen, and then calculate back to "Actual watt power per square cm into the pot", and compare "Actual" with the Absolute Standards" of 2,1,and 1/2 watts/square cm, apparently required for "good cooking and good cooking control"? Tests would be run to determine:</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>a: Stove performance at maximum power input to the pot when boiling water</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>b: Stove performance at 2 watt/square cm input to the pot when boiling water</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>c: Stove performance at 1 watt/square cm "normal maximum food cooking power"</span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>d: Stove performance at 1/2 watt/square cm "normal minimum food cooking power" </span></strong><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>Input fuel consumption, health parameters, and safety parameters would also be measured. If the 2,1, and 1/2 numbers were a bit off, they could easily be changed in the future, with the same test protocol.</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>5:</span></strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'> <em><span style='font-family:"Arial","sans-serif"'>></span></em></span><em><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Knowing the rate of fuel burning at that time enables calculation of the required TDR. </span></em><o:p></o:p></p><p class=MsoNormal><em><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The rate of mass loss is one thing, what is burning is quite another. Frank and I have been discussing how to refine that! It is not so simple with biomass, and is much more difficult it there is a lot of char involved, but not impossible.</span></em><o:p></o:p></p></div><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'># If you knew the "total energy in the fuel charge, at the start", and the energy remaining in the fuel after the test is complete, there may be an error in the absolute sense as a result of pro-rating energy consumed over the burn time, but the error would be consistent. It would thus be fair to all stoves, and should thus give a repeatable ranking of all stoves. Is there a better way to do things than weighing the fuel as it disappears, and assuming that "energy release is proportional to loss of fuel weight"?</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>Thanks for your insight into what goes into configuring a good stove test.</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>Best wishes,</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><strong><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>Kevin</span></strong><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><p class=MsoNormal><span lang=EN-CA>----- Original Message ----- </span><o:p></o:p></p></div></div><blockquote style='border:none;border-left:solid black 1.5pt;padding:0in 0in 0in 4.0pt;margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><div><p class=MsoNormal style='background:#E4E4E4'><b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'>From:</span></b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'> <a href="mailto:crispinpigott@gmail.com" target="_blank" title="crispinpigott@gmail.com">Crispin Pemberton-Pigott</a> </span><o:p></o:p></p></div><div><p class=MsoNormal><b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'>To:</span></b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'> <a href="mailto:stoves@lists.bioenergylists.org" target="_blank" title="stoves@lists.bioenergylists.org">'Discussion of biomass cooking stoves'</a> </span><o:p></o:p></p></div><div><p class=MsoNormal><b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'>Sent:</span></b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'> Saturday, May 04, 2013 9:01 PM</span><o:p></o:p></p></div><div><p class=MsoNormal><b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'>Subject:</span></b><span lang=EN-CA style='font-size:10.0pt;font-family:"Arial","sans-serif";color:windowtext'> Re: [Stoves] Stove Definition - controllability</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p></div><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Kevin</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><div><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>The question of "What is an acceptable Turn-Down Ratio?" (TDR) is not a simple one.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Actually, the cooks make it quite simple. If they cannot turn it down far enough to stop burning their food, they won’t use that stove for that purpose. Obviously the food preparation methods vary widely around the world so there is no ‘standard’ TDR which will satisfy everyone. That is we I consider the local comparative performance test the most relevant for any stove programme. That said, it is worth discussing the idea of a <i>minimum</i> ratio for performance reviews.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Fundamentally, the Cook has to control the heat to the pot for two reasons:</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>1: To cook it properly</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>2: To cook it efficiently</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I agree these are the considerations the cook applies.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>If the stove does not have an adequately high TDR, the Cook may be able to compensate by:</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>1: Adding extra water and allow it to boil off</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>2: Move the pot to a cool part of the stove top.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The methods reported are:</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Taking off the lid which reduces the effective heating power by creating a large additional loss of heat from the whole pot.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Adding cold water.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Moving the pot away from the fire laterally.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Elevating the pot/food above the fire (common with roasted meat in a standard BBQ)</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Stopping any fanning of the fire</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Removing fuel (fuel metering)</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Closing air vents (air metering)</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Splashing water on the fire (also common with a BBQ)</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Adding a wet piece of fuel</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Removing a heat transfer increasing device like a pot skirt</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Moving the pot to a second or third (etc) hole on the stove where the heat is less intense (common in Indonesia)</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Venting ambient air into the chimney to reduce the draft (arguably a form of air metering – used by John Davies in his packed bed coal gasifier)</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Inserting a plate between the heat source and the cooking vessel</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Transferring the pot or the contents of the pot to a retain heat cooker.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>>…</span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Thus, a TDR of perhaps only 2 may suffice with a non-covered pot, while a TDR of 6 may be required if the pot is covered. </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>While I understand your point, the standardisation of a minimum requirement would consider dominant cooking methods and allow the market to sort out the different between, say, 4:1 and 6:1 products. </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>The required TDR will depend on whether the cooking pot is covered or not.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I believe the cook will have a practical approach: if the food is going to cook adequately (meaning not at a particularly high power which another stove may have) there should be a minimum cooking power and a minimum turn down. I do not like the idea that it has to be a particular number of Watts that the stove has to yield or turn down to. The reason for this is there are a large number of cooking appliances for a wide range of things and any stated limit will immediately rule out stoves that are perfectly capable of delivering a needed cooked product. In order to have a viable and broadly applied standard, it will have to be relative to some stated ratios rather than ranges. It is reasonable for a national standard for domestic stoves to have an upper power limit on what is considered ‘domestic’.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If a pot lid is off by local convention, the net cooking power will necessarily be reduced for any given firepower. I cannot state with certainty that it will allow the proper cooking of all foods with a lower TDR. It might even have to be higher. Remember that the only viable method of determining the TDR is to test the amount of heat getting into the pot and even with the lid off, at low temperatures that rate is pretty much the same as a pot with a lid on. In other words the ΔT and the water evaporated are still going to give a realistic value of heat gained, even if more of that heat is passed into the air in the form of water vapour. I am not convinced the reduced cooking efficiency (net heat in water) is lower or higher.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>>…</span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>One notable exception would be when the Cook purposely wants to boil away excess water, to thicken the food.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I feel this does not impact the TDR.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Also, the maximum heat input rate to the pot, ie "pot power", will have an effect on the required TDR. </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Aha. Well this is not the case. The definition of the turn down is not the firepower, it is the heat gained by the pot. Interestingly, there are major outcomes from this conceptual difference. The WBT’s classically observed the fire but people do not cook with the heat of the fire, only the part which gets to the pot. As you have observed, the heat transfer efficiency varies with firepower and therefore stating a minimum TDR does not really say anything about the firepower involved, only the cooking power.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>In summary:</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>1: For most efficient cooking, and to reflect most common cooking practises, the pot should be covered.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>That is not relevant to the TDR, though an important programmatic consideration.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>2: Heating pots with no cover will require more cooking fuel, but by addition of water, burning or scorching of foods can be prevented, with a lower TDR. This assumes that adding water during cooking is acceptable to the Cook.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>That is a cooking technique, not a TDR.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>3: .A stove heating a covered pot will require a larger TDR than a stove heating an open top pot with no cover.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This is debatable and so far I am not convinced.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>4: A stove with "high pot power input" will require a larger TDR than a pot with a lower "pot power input."</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>This is a no-no because to embed the concept into a Standard means interfering with preferences of the manufacturer and customer. The deal is between the buyer and the provider, not the regulator. The regulations are there to protect the customer and to label a product as being able to perform certain things, such as to deliver a locally acceptable water boiling rate in a pot with a diameter of 150mm or 300mm (as per the label on the product). The customer knows full well that a stove that cooks ‘well’ with a 250mm diameter pot will have problems getting the same cooking experience out of a 400mm diameter pot. What is not permissible is to have a manufacturer claim that the product ‘cooks well’ with a 400 when a test of the heat transfer rate shows it will only do so if the pot is about 250 in diameter.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>With respect to controllability, a cooking stove needs some form of power regulating in terms of the heat getting to the pot. How that is achieved is up to the manufacturer. I have seen one stove that could turn down only about 10% and the mechanism used was to stop producing so much CO2 and produced CO instead. It worked…..!</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='color:windowtext'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>The actual TDR required can be measured with present day instrumentation in common use. Once the maximum "high pot power input" rate is measured, the fire can be turned down, or allowed to die down slowly, and the point where water temperature starts to fall can also be measured. </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Unfortunately that turns out to be imprecise. It is best to determining the heat transfer rate using cold pots of water, swapping them when the water reaches 65 to 70 deg C( before any evaporation takes place). It is quite easy to get a 2-3% precision on the whole operation (depending on the fuel type and the care take to measure it).</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-family:"Arial","sans-serif";color:#1F497D'>></span><span lang=EN-CA style='font-family:"Arial","sans-serif";color:windowtext'>Knowing the rate of fuel burning at that time enables calculation of the required TDR. </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The rate of mass loss is one thing, what is burning is quite another. Frank and I have been discussing how to refine that! It is not so simple with biomass, and is much more difficult it there is a lot of char involved, but not impossible.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks so much for your thoughtful inputs.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div class=MsoNormal align=center style='text-align:center'><span lang=EN-CA style='color:windowtext'><hr size=2 width="100%" align=center></span></div><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-CA style='color:windowtext'>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/" target="_blank">http://stoves.bioenergylists.org/</a></span><o:p></o:p></p></blockquote><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Arial","sans-serif"'><br>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/">http://stoves.bioenergylists.org/</a><o:p></o:p></span></p></div></div></body></html>