<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:"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 bgcolor=white 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 Lanny<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'>I wonder if you can help me out with more numbers. The comparison between a trough with ends and a pot is interesting. <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'>Can you provide some water boiling volumes (initial) and mass of fuel burned? To check heat transfer efficiency the char mass will be needed. To check the system efficiency (fuel efficiency) the char should be ignored in most cases. What I would like to do is calculate the two and see if the surface area of the pot and vat are important considerations. They should be, but as I often say, never assume anything.<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'>Best to check.<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 effective heating area of the vat might be the sheet length x Sin(45) x Sheet width, or it may be sheet length x width. If the heat transfer efficiency per sq cm is the same, then the matter will soon be settled with a calculator.<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'>Thanks<br>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><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>Lanny Henson<br><b>Sent:</b> Monday, July 29, 2013 12:13 AM<br><b>To:</b> Discussion of biomass cooking stoves<br><b>Subject:</b> [Stoves] Pot shells / Fin shells<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:13.5pt'>Fins/ pegs/ pot shells/ rocket pots.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>If you are going to use fins they should be attached to a pot skirt that fits snug and stays on the pot until it needs to be cleaned. This keeps the soot if any contained and away from the cook.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>Instead of a fin shell I am now using a "pot shell" that totally encloses the pot. The pot shell has a top tray that can be easily slid back for easy access to the pot. This is actually easier that removing a lid and another benefit with total enclosure is the pot is heated from the top as well as the sides and bottom.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>The top tray can also dry wood and warm food items. </span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>Another benefit of the pot shell is that it makes cooking in the rain possible.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>The construction is very simple and it can be built from most any material that is non combustible.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>A section of drum fits over a 40 qt sauce pot or a 60 qt stock pot. The pot handles may have to be bent in a little or the pot shell can be slightly oval to fit over the handles.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>A pot shell requires a flat top stove body or a burner under a flat surface.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>I believe the pot shell is the biggest bang for the buck to improve a stoves performance. They are cheep and easy to build. They add draft without allowing too much, they capture the heat, and allow cooking outdoor in the rain.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>If the pot shell design helps your stove, run with it, and that goes for everyone.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>I will have a video later today showing its use</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:13.5pt'>Lanny</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div></div></body></html>