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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoPlainText>Dear Andrew<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>I will keep it short so you can access it.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>>I was only addressing the definition<o:p></o:p></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>Agreed.<o:p></o:p></span></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>>What you are are seeing is vagaries of the way measuring equipment makes assumptions about how the sensor reacts to the exhaust species and produces an output.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='color:black'>That is what we assumed right from the start and it turned out not to be the case. I hoped it was an instrument issue. It is a formula issue.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>So I researched how that formula is supposed to work and does work, but not for rocket engines. If not for rocket engines, why would it work for rocket stoves? </span><span style='font-family:Wingdings;color:black'>J</span><span style='color:black'> <o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>So the real-real answer is that EA represents available O2 as if it were air. No problem that is the definition. But to get the right answer it has to be a % of the O<sub>2</sub> actually required at the time.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>What is required at the time changes with the chemistry at the time. That chemistry can be directly measured using gas analysers.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>Interestingly, for the same level of O<sub>2</sub> in the stack, the EA is different under different chemical conditions. Complex pyrolysing conditions provoke all sorts of strange chemistry so the chemically balanced approach is required, actually. For a given device, the best combustion tends to take place under a certain EA level, but this varies (a lot) between devices. The BLDD6 coal stove works best with 30% EA which is a very low value and really surprised me. I would have guessed that was not possible.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>Regards<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>Crispin<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p></div></body></html>