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</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'>Dear Paul<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'>We are developing the science of a future industry. It is important that basic issues be discussed, pounded out if necessary, so that we lay the foundations of a better future for all. <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'>As you are fully aware, stoves are complicated and involve many sciences. On this list we tend to concentrate on the technical aspects of stoves because of mutual interest. The inclusion in recent years of more and more young, talented ‘engineering’ oriented people has been such a welcome sight. EWB had been doing things with stoves in the field creating enthusiasm for what has been a pretty obscure side of development.<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'>Through careful effort and sometimes conscious plotting, the World Bank, the FAO, USAID, many national governments and NGO’s have dipped their toes into the ‘hot water’ of improved stoves. It has gained respectability and full time professional careers are now possible in this field.<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 discussion about radiation and thermal efficiency is not new to this list, but missing has been the worked examples how the physics of stoves plays out. We misunderstood your message about boiling rates. So what? We had a great discussion, we learned about radiation physics and now we have a tool that can be used to teach the important of my favour topic: excess air!<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 reduce excess air, you raise the temperature of the flame and all radiation parts! Play with that spreadsheet for a while and see where the radiant energy peaks and then it is nearly zero. I found combinations of parameters that are believable and showed 50% of heat in the pot was from radiation.<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'>Further on this point, Prof Annegarn stated categorically this morning that the amount of energy you can get to a pot from convection cannot be increased by transforming it to radiant heat. Something about the second law of thermodynamics. Your experiment of with-and-without the dome showed this to be the case, even with a large dome. Very valuable work. <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'>Keep it up!<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<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>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><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 0mm 0mm 0mm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>+++++++</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'><o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dear Paul.<br>Who amongst us has has not fallen short by times.<br> If ye gnarly doers leave then kiss the list goodbye.<br><br>As list member, or not, your contributions are appreciated by many.<br>Best wishes, have fun,<br>Alex<br><br><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>