<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=us-ascii"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Helvetica;
panose-1:2 11 6 4 2 2 2 2 2 4;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0mm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
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:0mm;
mso-margin-bottom-alt:auto;
margin-left:0mm;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.EmailStyle18
{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:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
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-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Dear Otto<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>The claim, if presented as a comparison between the energy that goes into a power station compared with the fuel burning in a stove is an apples and oranges comparison because the energy that went into making the wood is not considered.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>It is presented of course in a patently misleading manner as if an open fire is ‘efficient’. It depends on how much of the tree is wasted in the field, how much is lost during ignition and how much is left smouldering after the cooking is finished.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>It is this sort of thing that gives stoves projects a bad name.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>As for time to boil, a Vest stove will boil water at a rate of 3 minutes per litre measured from the time of ignition, i.e. light the match and start the clock, and it will boil 2.5 litres in 7.5 minutes. That is much faster than anything on the chart. I wonder why it is not included as it has been available for 10 years. The Peko Pe has been available much longer.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>The way to really misrepresent the performance of a stove in terms of its fuel consumption is to calculate the energy used in the fire rather than the energy that was standing in the forest when the fuel cycle started. Then compare it with the energy in the ground that needs to be dug up to make electricity.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>The numbers quote for an induction cooker are clearly wrong. Yixiang Zhang and I looked at every model available in a Chinese mall and none were less than 88% efficient. So even the worst of them, from, power station to hot water, is more efficient that the most perfectly operated open fire not counting forest losses and burnout.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>And that’s enough of that.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0mm 0mm 0mm'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> Stoves [mailto:stoves-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Otto Formo<br><b>Sent:</b> Saturday, July 05, 2014 1:02 AM<br><b>To:</b> Stoves Bioenergylist<br><b>Subject:</b> Re: [Stoves] Key differences of performance test protocols for household biomass cookstoves<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-family:"Calibri","sans-serif"'>Dear stovers,<br> <br>I do not know what kind of gasifier unit the Low Tech Magazine, are refering to and have tested, but for sure, the ND Peko Pe, will boil 2,5 L of water in less than 10 mins, using wood pellets from Pine. (Woodchips or almost any type of dry biomass, moisture content less than 15%, will do the same).<br>That should indicate a different result, mentioned in the diagram, where the gasifier came third.<br> <br>The efficiency of the Peko Pe, tested in Copenhagen in 1996, varied from 25 - 29%, depending of the type of fuel.<br> <br>How the Rocket stove can reach a therminal efficiency up to 54%, is to good to be true.<br> <br>Have a Nice summer.<br> <br>Otto<br> <o:p></o:p></span></p><div><div><div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0mm 0mm 0mm 6.0pt;margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><div><div><div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'>Dear Crispin - thank you for sharing this, <o:p></o:p></span></p><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'>Have you (or anyone else) by any chance read this article <a href="http://www.lowtechmagazine.com/2014/06/thermal-efficiency-cooking-stoves.html" target="_blank">http://www.lowtechmagazine.com/2014/06/thermal-efficiency-cooking-stoves.html</a> <o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'>It a real mind turner to say the least.... I would be very interested to hear some of your thoughts on this matter. To quote one of the opening paragraphs - <o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><i><span style='font-family:"Calibri","sans-serif"'>''</span></i><i><span style='font-size:10.5pt;font-family:"Helvetica","sans-serif";color:#444444'>In fact, an electric cooking stove is only half as efficient as a well-tended open fire, while a gas hob is only half as effective as a biomass rocket stove. And even though indoor air pollution is less of an issue with modern cooking stoves, research indicates that pollution levels in western kitchens can be surprisingly high.'' </span></i><span style='font-family:"Calibri","sans-serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'>The author then follows that article up with this one - <a href="http://www.lowtechmagazine.com/2014/07/cooking-pot-insulation-key-to-sustainable-cooking.html" target="_blank">http://www.lowtechmagazine.com/2014/07/cooking-pot-insulation-key-to-sustainable-cooking.html</a><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'>What do you think? I think I need to double my forestry efforts. <br><br>Kind Regards, <o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Calibri","sans-serif"'>Teddy <o:p></o:p></span></p></div></div></div></div></div></div></div></div></blockquote></div></div></div></div></div></div></body></html>