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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='color:#1F497D;mso-fareast-language:EN-US'>Dear Paul vd S<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>I appreciate you presenting this information. There is a great deal of merit in the use of such systems on stoves – largely because of the control it affords over power. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>There are other devices which can generate the power needed to operate a fan (or other appliance) and multiple variants of the TEG. In future these will be more important than they are now as the power and efficiency rises. At that time the discussion about fuel consumption to feed the electric power generators will be very relevant.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>The small stoves with a limited power generating capacity (5W or so) sold in Uganda are, I hear, increasing fuel consumption because people use the stove all day to power a radio. In other words the problem has already been manifested, and it will have to be addressed by stove promotion programs.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>I trust you are well.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Thanks<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Dear AJH,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>The Philips stove does NOT use significantly more fuel because of the attachment of the TEG.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>The TEG unit takes around 100 W of heat from the fire. 98W is waste heat of the unit (2% efficiency). That 98 W is recirculated into the fire because it is used to preheat the combustion air.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>The remaining 2W is fed to the fan. In the fan 1.8W is transformed into heat (just 10% efficient). Also this 1.8W is fed back to the fire.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>So just 0.2W is actually taken from the fire. An estimated 80 % of that power is lost as pressure drop over the nozzles that feed the fire with high velocity air. That loss is gain transformed into heat that comes into the fire.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>So the real power taken is around 0.04W. That needs to be compared to the power produced: 4000W. So an estimated 1/100000th extra fuel might be required.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>The might comes from the fact that in this case the energy lost is caused by the kinetic energy of the air moving away from the fire. But even a natural draft stove has these losses.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>So it is safe to assume that with the Philips construction NO additional wood is required because of the use of a TEG.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Kind regards,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Paul.<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><u><span lang=NL style='font-size:24.0pt;font-family:Webdings;color:green'>P</span></u></b><u><span lang=NL style='font-size:10.0pt;font-family:"Arial",sans-serif;color:blue'> </span></u><span lang=EN-GB style='font-size:10.0pt;font-family:"Comic Sans MS";color:green'>Take care of the environment, print only if necessary ...</span><span lang=EN-GB style='font-size:12.0pt;font-family:"Times New Roman",serif'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman",serif'><o:p> </o:p></span></p><div class=MsoNormal align=center style='text-align:center'><span lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman",serif'><hr size=2 width="100%" align=center></span></div><p class=MsoNormal><span lang=EN-US style='font-size:7.5pt;font-family:"Arial",sans-serif;color:gray'>The information contained in this message may be confidential and legally protected under applicable law. The message is intended solely for the addressee(s). If you are not the intended recipient, you are hereby notified that any use, forwarding, dissemination, or reproduction of this message is strictly prohibited and may be unlawful. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.</span><span lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman",serif'><o:p></o:p></span></p></div></body></html>