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</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'>Howzit Ken?<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'>It will induce a lot of draft and is a very good method of preheating. The Vesto stove uses this as a balancing force to overcome the tendency of small stoves to have too much excess air drawn in a bottom hole and a top outlet.<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'>If you are drafting the air upwards, you can used the standard draft calculation method. There is a draft calculator on the Bioenergy lists website.<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'>It will model down-drafting as the air preheats too, in the section on the right. This is used in both the Vesto and the Lion Stove. The careful placement of the air entry points can produce an auto-balancing draft that will limit EA under a wide range of power conditions without operating a draft control mechanism (damper or </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>ë</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> controller).<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'>It is worth remembering that the heat exchanged off a vertical round pipe is exactly double that of an open air horizontal round pipe. It might be relevant to some portion of the stove.<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'>Regards<br>Crispin<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><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Here's a related question,<br><br>Suppose I have a vertical metal cylinder that is being heated by combustion gases from the inside - for the sake of argument - like a 48" length of 12" diameter 316 stainless steel flue pipe.<br><br>Let's assume that this pipe is getting hot - dull orange, even when the outer surface is exposed to free air.<br><br>If I then enclose this pipe in an annular sleeve - again 48" long - open at each end, like a 14" diameter tube - so that there is a 1" annular gap for air to freely be drawn into, will the effect of this sleeve create a beneficial flue effect, and increase the velocity of the cooling air draught around the flue pipe?<br><br>I'm considering this arrangement as a means of delivering preheated air, and providing cooling to a large woodgas burner.<br><br>Any thoughts <br><br><br><br>Ken <o:p></o:p></p></div></body></html>