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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'>Dear Martin<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 so much for that third link. It is a good example of a setup up designed to improve the system efficiency. It has Lambda control (excess air) and there is a little graph showing the EA+1 (</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'>). They are targeting 30% excess air. That, plus the used air = 1.3 as shown on the chart.<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'>This low level of EA can be achieved with gaseous fuels and with more difficulty, some solid fuels if they are predictable.<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 shooting blind with a new design, I can suggest that you try for 80-120% excess air for coal and wood, and 50-100% for other fuels. Wood can burn really well at 50% but most stoves can’t maintain that level.<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'>With a gasifier you should be able to get to 50% but the gas is likely to be variable and it may not support a clean burn all the time. I have been very recently working on a downdraft coal stove that seems to work best at 35-40% which was a surprise, actually. That is low for coal. It has a lot of strong mixing in a confined space which may explain it. <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'>The very short flames </span><span lang=DE style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>shown at </span><span lang=DE style='font-size:10.0pt;font-family:"Arial","sans-serif"'><a href="http://www.heizungen-wulfert.de/heizung_gasoel.html">http://www.heizungen-wulfert.de/heizung_gasoel.html</a><span style='color:#1F497D'> are because the fuel is made of very short HC chains.</span><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>The animation is at </span><span lang=DE style='font-size:10.0pt;font-family:"Arial","sans-serif"'><a href="http://www.viessmann.de/de/flash/animation_lambda_pro.html"><span lang=EN-GB>http://www.viessmann.de/de/flash/animation_lambda_pro.html</span></a></span><span lang=EN-GB style='font-size:10.0pt;font-family:"Arial","sans-serif"'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></body></html>