<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"><base href="x-msg://1120/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Fran cc list</div><div><br></div><div> You are correct in having started this. (Not sure I want to thank you, since we are a long way from closure.) My concern in today's response to Crispin was partly on the meaning of what Paul Olivier was offering with the term "equivalency". That is still not a helpful term for me. But Crispin and I were only talking excess air - which is a great topic but I am still not understanding Crispin's views on why so much is wrong with the WBT (which I want to "Save") .</div><div><br></div><div> So I think we are still very much on target with your thread name "Saving the WBT". That is (maybe) what tomorrow's webinar is about - and (from my standpoint) the WBT also has to be about how much char is obtained and reported. </div><div><br></div><div> I can't think of a better laboratory method of comparing stoves than what is in the existing WBT. Excess air is a key part of getting high efficiencies, but not being so close to zero excess air that pollutants are too high. The present WBT gives some of that information (but nothing reported I think of EA = Excess Air) - and I think the existing equipment could also report an EA number (which will vary all over the place during a run for rockets, but will be fairly uniform for TLUDs).</div><div><br></div><div>Ron</div><div><br></div><div><br></div><div><br></div><br><div><div>On Aug 19, 2013, at 1:27 PM, "Frank Shields" <<a href="mailto:frank@compostlab.com">frank@compostlab.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Actually Ron it started with me and Saving the WBT : )<o:p></o:p></span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">But you do have a very interesting discussion going on and should continue. Perhaps changing the subject.<o:p></o:p></span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Regards<o:p></o:p></span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Frank<o:p></o:p></span></b></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 14pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></b></div><div><div style="border-style: solid none none; border-top-width: 1pt; border-top-color: rgb(181, 196, 223); padding: 3pt 0in 0in; "><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; ">From:</span></b><span style="font-size: 10pt; font-family: Tahoma, sans-serif; "><span class="Apple-converted-space"> </span>Stoves [mailto:stoves-<a href="mailto:bounces@lists.bioenergylists.org" style="color: purple; text-decoration: underline; ">bounces@lists.bioenergylists.org</a>]<span class="Apple-converted-space"> </span><b>On Behalf Of<span class="Apple-converted-space"> </span></b>Ronal W. Larson<br><b>Sent:</b><span class="Apple-converted-space"> </span>Monday, August 19, 2013 11:17 AM<br><b>To:</b><span class="Apple-converted-space"> </span>Discussion of biomass cooking stoves<br><b>Subject:</b><span class="Apple-converted-space"> </span>Re: [Stoves] Saving the WBT<o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">Crispin and list:<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> Sorry but I am even more confused than earlier.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> This discussion started with Paul Olivier's term "air equivalency ratio" and a number of 0.3 being good (I think only referring to a pyrolysis zone (Paul uses the term gasification - which bothers me a good bit. Tom MIles supports a sister list on gasification - where they are trying to get rid of all char, not save it as some of us [especially Paul] want on this list). You have not discussed this term (I will call AER) and so I repeat that I am going to ignore AER until I see a site I can read about it. I still do not know whether this AER term includes excess air (EA) - a term that you do discuss. If they are not totally different "animals" I will be surprised.<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> The problem is that your description of excess air (EA) does not comport with what I thought I knew. So I have read in the following, using the Google search term: "definition of excess air ratio" (The added "ratio" hopefully being OK). I read through these (without finding some of what you have below)<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="http://en.wikipedia.org/wiki/Air–fuel_ratio" style="color: purple; text-decoration: underline; ">http://en.wikipedia.org/wiki/Air%E2%80%93fuel_ratio</a><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="http://www.ohio.edu/mechanical/thermo/Applied/Chapt.7_11/Chapter11.html" style="color: purple; text-decoration: underline; ">http://www.ohio.edu/mechanical/thermo/Applied/Chapt.7_11/Chapter11.html</a><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="http://www.engineeringtoolbox.com/boiler-combustion-efficiency-d_271.html" style="color: purple; text-decoration: underline; ">http://www.engineeringtoolbox.com/boiler-combustion-efficiency-d_271.html</a><o:p></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="http://www.gilsoneng.com/reference/combustion.pdf" style="color: purple; text-decoration: underline; ">http://www.gilsoneng.com/reference/combustion.pdf</a><o:p></o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><a href="http://www.brighthubengineering.com/machine-design/15235-the-stoichiometric-air-fuel-ratio/" style="color: purple; text-decoration: underline; ">http://www.brighthubengineering.com/machine-design/15235-the-stoichiometric-air-fuel-ratio/</a><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> see more below<o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; ">On Aug 19, 2013, at 10:00 AM, Crispin Pemberton-Pigott <<a href="mailto:crispinpigott@gmail.com" style="color: purple; text-decoration: underline; ">crispinpigott@gmail.com</a>> wrote:<o:p></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Dear Ron</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Very good question and correctly put.</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Excess air is air above and beyond the need of the fire to have stoichiometric combustion. Typically for good heat transfer efficiency and a good CO burnout it should be between 50% and 150% with 80% being typical. It is rare to get a <25% EA value and get low CO and H2.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL: agree totally]</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">So, what happens if the excess air drops to 0%? Then it means there is air getting in, but only enough to run the combustion theoretically. In practise there is a lot of CO and H2 that does not get burned because those molecules can’t find that last remaining O2molecules available.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL: agree totally]</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">The normal calculation of EA is actually not correct from a chemically balanced point of view. That is why I developed the chemically balanced EA calculation embedded in the<span class="apple-converted-space"> </span><i>HTP</i><span class="apple-converted-space"> </span>spreadsheet. Very briefly, think of it this way. A rocket engine using solid fuel burns in the emptiness of space without any air at all. How? The O2 is embedded in the chemicals that make up the fuel. It is quite possible to have excess air (equivalent) in a space rocket. So…what is the difference between that and a fuel that has a lot of oxygen in it? Only scale. Biomass has a lot of oxygen in it. Cold damp fires can also generate O2 from water using the water gas shift reaction.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL: Where do I go to see this<span class="Apple-converted-space"> </span><i>HTP </i>spread sheet? Why is the "normal" approach not good enough? I don't find the comparison to a rocket fuel (a lot of Aluminum) helpful.</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">All these things are taking place in a stove so we need a way to calculate what the available oxygen is and turn that available O2 into a figure that means something – a metric for available ‘air’ which is actually oxygen treated as if it was the amount of air that would contain that much oxygen. If I roast wood in a retort at low pressure I can extract quite a lot of oxygen. It might react with H2, it might not.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <span class="Apple-converted-space"> </span><b>[RWL: I don't see why stove designers or testers should need to worry about the O2 in the fuel. Nothing I have read gets to that level of detail. You can measure the O2 in the fuel, in the incoming air, in the resulting char, and in the exhaust stream. Every fuel is different. Every stove is different. Why calculate anything - why not measure?</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Back to the EA being zero. When the EA is 0%, the O2 that is available might come from the fuel (burning biomass) or from some air (kerosene fire).</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL: If EA = 0, there should be no "O2 that is available". What am I missing in this 2nd sentence? Why introduce kerosene into this? I hope stove testing doesn't have to report the O2 levels of starting fuels.</b><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Where it comes from is not so important, we just need a metrics for correcting calculating how much of it there is so we have a clue what to do to improve combustion.</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Standard EA is</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><u><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> O2-(CO/2) <span class="apple-converted-space"> </span></span></u><u><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: white; ">.</span></u><span lang="EN-CA"><o:p></o:p></span></div></div></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt; "><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">21- [O2-(CO/2)]</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div></blockquote><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <span class="Apple-converted-space"> </span><b>[RWL: I have found this formula nowhere. Cite? What i have found is that EA can be found from either measuring O2 or CO2, no need for bringing CO into this one formula. I recognize that CO is important, but for a useful stove (not a charcoal using stove), this has to be a very small modifier on a term that we aren't even reporting in the tests (but I would like to know). Giving just O2 levels in the exhaust stream would be very illuminating.</b><o:p></o:p></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><br><br><o:p></o:p></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">It gives the wrong answer for real fire burning any fuel that contains O2, like wood or coal but gives a pretty good answer for fuels like kerosene or pure charcoal.</span><span lang="EN-CA"><o:p></o:p></span></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL A cite for this "wrong" statement? I view O2 level measurements important in knowing how to optimize efficiency. CO is important for health reasons and knowing more about combustion efficiency. But since high CO leads to low EA numbers in this formula, we should be careful of your (only your?) definition.</b><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><br><br></b><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">When the fire (pyrolysis) is dependent mostly on O2 from within the fuel, the amount that has to be added in the form of air is far less than the stoichiometric necessity. So, how to quantify that amount?</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <span class="Apple-converted-space"> </span><b>[RWL: We should be talking separately about "flaming pyrolysis" in TLUDs (or maybe some gasification approaches) and retorts With the latter, no O2 is added. The available O2 is no doubt important in a retort operation, but since we can't control it, I see little reason to quantify it, except in very general terms Retorts are not very attractive in stove designs because they are not controllable. I can't see any value in the term EA (or AER) with operation of a retort (and some aspects of a retort are probably occurring in TLUDs).</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">The analysis that says the air supply was 1/3 of that needed by the fuel is determined by measuring the chemistry in gas produced. Depending on how the analysis is done, it may also give a consistently wrong answer – I did not check yet but all the indications of over-simplification are there.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <span class="Apple-converted-space"> </span><b>[RWL: The chemistry is very different with the rate of temperature increase (that is fast and slow pyrolysis give very different product streams. I can't see how any form of computation is worth the effort. It looks to me like simplification is badly needed. Doing zero computation looks OK to me</b><o:p></o:p></div></div><div><blockquote style="margin-top: 5pt; margin-bottom: 5pt; "><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Whether the answer is ‘right’ or not, there is usefulness in having a metric for the amount of air that was theoretically the minimum to burn the fuel.</span><span lang="EN-CA"><o:p></o:p></span></div></div></blockquote><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <span class="Apple-converted-space"> </span><b>[RWL: Paul raised this issue in the context of pyrolysis. Not "burn the fuel". Every char output is different, even with the same run for different locations in the stove. And I am not understanding the term "metric" here. And I think we should care about answers being<span class="Apple-converted-space"> </span><i>"'right' or not"</i></b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">With a gas-maker, the amount will be expressed as a fraction or % of the stoichiometric air demand. The result is a gas with some O2 in it (in the form of CO and CO2 and maybe HO and so on) but not nearly enough, all taken together, to burn the gas. That is the point of a gasifier – to make unburned fuel that can be burned in a gas stove.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL: I guess we have a few promoting gasifier stoves, but why not simply combust (as in a rocket) if you don't care about char. The TLUDs are being promoted largely because they are not gasifiers - they are pyrolyzers with an intent to produce char (the definition of pyrolysis). The original discussions on this list about TLUDs only were on how to do better than the 10-20% conversion of most char-making in the bush. I'd like to see a rewrite of this paragraph addressing TLUDs and retorts. I don't see any difficulty in comparing stoves that operate on a total combustion philosophy or a gasification (minimum char) philosophy. One operates on a parallel process philosophy and the other on series. The final results as a stove could differ a lot on pollutants, but the testing should go similarly. Not so for pyrolyzers. Something theoretical on the production of particulates and CO (and PAHs) could be very helpful for stove designers.</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">So in order to discuss how much air was supplied, we need a way to talk about it. It is expressed using a metric that is based on the elemental analysis of the fuel. Therefore if you change the fuel, it changes the need for air in absolute terms but maybe not in relative terms. We can live with that – it at least put the discussion on the page in a manner that other can follow.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <b>[RWL: You have a big "maybe" there. In one cite I found, the air/fuel stoichiometric ratio for wood combustion was given as 4-7. I'll bet the equivalent "metric" for primary air in making char is wider. I wouldn't even know how to define it, since it will vary with the magnitude of the primary air flow (related directly to the power out). Maybe we are talking about defining a term that, if too low, will not support pyrolysis, but if too high will give soot on the cook pot (or similar). We are getting close to a metric that will describe TDR = turn down ratio. EPA testing (webinar tomorrow) could determine this perhaps (with a change in procedures). This "metric" (if it exists) could involve fuel elemental analysis, but I guess involves a lot more. Mostly, the high end is likely to be limited by the amount of primary air, which is limited by the draft, fan speed, etc. The low end influenced maybe by the intensity of the radiative transfer.</b><br><br><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Because the metric is based on the elements in the fuel, it is possible it is, unlike the standard EA calculation, correct ‘chemically’. We will have to check. That is the sort of check we should be doing for all metrics before we run off to make them international standards. Obviously.</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "> <span class="Apple-converted-space"> </span><b>[RWL: In summary, I think you are raising issues that are hopelessly complicated for the world of stove testing and comparisons. I see insufficient reason so far to explore your metric words "possible" and "to check" and "Obviously". I hope you will try again to convince this list (with citations), if you disagree.</b><o:p></o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b>Ron<br><br></b><o:p></o:p></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Regards<br>Crispin</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="border-style: solid none none; border-top-width: 1pt; border-top-color: rgb(225, 225, 225); padding: 3pt 0in 0in; "><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><b><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">From:</span></b><span class="apple-converted-space"><span style="font-size: 11pt; font-family: Calibri, sans-serif; "> </span></span><span style="font-size: 11pt; font-family: Calibri, sans-serif; ">Stoves [mailto:stoves-<a href="mailto:bounces@lists.bioenergylists.org" style="color: purple; text-decoration: underline; ">bounces@lists.bioenergylists.org</a>]<span class="apple-converted-space"> </span><b>On Behalf Of<span class="apple-converted-space"> </span></b>Ronal W. Larson<br><b>Sent:</b><span class="apple-converted-space"> </span>Monday, August 19, 2013 11:15 AM<br><b>To:</b><span class="apple-converted-space"> </span>Discussion of biomass cooking stoves<br><b>Subject:</b><span class="apple-converted-space"> </span>Re: [Stoves] Saving the WBT</span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA">Crispin and list:<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA">Crispin and list:<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> Sorry. Still not understanding. Who in the stove business has a problem with excess air that is too small? I read about EA ratios of 3, 4, 5…., not 0.3, 0.4, 0.5 ...<o:p></o:p></span></div></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA">Ron<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA">On Aug 19, 2013, at 9:06 AM, "Crispin Pemberton-Pigott" <<a href="mailto:crispinpigott@gmail.com" style="color: purple; text-decoration: underline; "><span style="color: purple; ">crispinpigott@gmail.com</span></a>> wrote:<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"><br><br><br><o:p></o:p></span></div></div><blockquote style="margin-top: 5pt; margin-bottom: 5pt; "><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Dear Ron</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="color: rgb(31, 73, 125); ">></span><span lang="EN-CA">I am going to stay away from equivalency ratio until I see some way to use it.<o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">It is used to talk about the air supply when there is no excess air available. Once EA goes to 0%, how do you describe a further reduction in the air supply?</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">So that is the use for it.</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Regards</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Crispin</span><span lang="EN-CA"><o:p></o:p></span></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span><span lang="EN-CA"><o:p></o:p></span></div></div></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 13.5pt; font-family: Helvetica, sans-serif; ">_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org" style="color: purple; text-decoration: underline; "><span style="color: purple; ">stoves@lists.bioenergylists.org</span></a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" style="color: purple; text-decoration: underline; "><span style="color: purple; ">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</span></a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/" style="color: purple; text-decoration: underline; "><span style="color: purple; ">http://stoves.bioenergylists.org/</span></a></span><span lang="EN-CA"><o:p></o:p></span></div></div></blockquote></div><div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA"> <o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span lang="EN-CA" style="font-size: 13.5pt; font-family: Helvetica, sans-serif; ">_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org" style="color: purple; text-decoration: underline; "><span style="color: purple; ">stoves@lists.bioenergylists.org</span></a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" style="color: purple; text-decoration: underline; "><span style="color: purple; ">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</span></a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/" style="color: purple; text-decoration: underline; "><span style="color: purple; ">http://stoves.bioenergylists.org/</span></a><o:p></o:p></span></div></div></div><div style="margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><o:p> </o:p></div></div></div>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org" style="color: purple; text-decoration: underline; ">stoves@lists.bioenergylists.org</a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" style="color: purple; text-decoration: underline; ">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/" style="color: purple; text-decoration: underline; ">http://stoves.bioenergylists.org/</a><br><br></div></blockquote></div><br></body></html>