<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Arial; font-size: 12pt; color: #000000'>Crispin cc "stoves"<br><br> See below.<br><hr id="zwchr"><b>From: </b>"Crispin Pemberton-Pigott" <crispinpigott@gmail.com><br><b>To: </b>"Discussion of biomass cooking stoves" <stoves@lists.bioenergylists.org><br><b>Sent: </b>Monday, May 6, 2013 10:06:54 AM<br><b>Subject: </b>Re: [Stoves] Definition of char-making appliance<br><br><style><!--
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</o:shapelayout></xml><![endif]--><div class="WordSection1"><p class="MsoNormal"><span style="color:#1F497D">Dear Ron</span></p><p class="MsoNormal"><span style="color:#1F497D"> </span></p><p class="MsoNormal"><span style="color:#1F497D">Stove testers are not carriers of opinions on social benefits, that is for regulators. This definition is for an ‘appliance’ because that is the correct term for a ‘device’ used for cooking. <br></span></p><p class="MsoNormal"><span style="color:#1F497D"> <b>[RWL1: So is the word "stove" used - and is so used by GACC. They use the term "stove", not "appliance" in 4.2.2.</b></span></p><p class="MsoNormal"><span style="color:#1F497D"><b></b><br></span></p><p class="MsoNormal"><span style="color:#1F497D">They are in fact domestic appliances in this case. A toaster is not a stove. A kettle is not a stove. They are cooking appliances and will be regulated.</span></p><p class="MsoNormal"><span style="color:#1F497D"><b> [RWL2: So you are confirming my guess that you are trying to separate the words "charcoal-making" and "stoves". That is not the case now and I ask why you want to not call a CMS (Charcoal Making Stove) a stove, but rather (I gather) a CMA?</b></span></p><p class="MsoNormal"><span style="color:#1F497D"><b></b><br></span></p><p class="MsoNormal"><span style="color:#1F497D"> </span></p><div><div><p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="color:#1F497D;mso-fareast-language:EN-CA" lang="EN-US">></span></b><span style="font-family:"Arial","sans-serif";color:black">The number 15 % could be useful. I can't think of a better number, if we need this, since 15% is easy to achieve.</span><span style="font-family:"Arial","sans-serif";color:#1F497D"></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D">I chose the number because it is easy to achieve and I want to eliminate stoves that are just ‘lousy burners of the fuel’ like the so-called Namibian Tsotso. They may or may not produce copious amounts of partly burned wood. That is not a char making stove, in my view.</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D"> <b>[RWL3: Does the tsotso make 15% char? Whether any particular stove does or doesn't perform well shouldn't be part of this discussion. If the Tsotso is a critcal example of bad testing of charcoal-making stoves (CMSs), I hope you will explain why.] </b><br></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Arial","sans-serif";color:#1F497D"><br></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Arial","sans-serif";color:#1F497D">></span><span style="font-family:"Arial","sans-serif";color:black"> I would make NO or LITTLE distinctions in the way 4.2.2 tests are performed and reported for char production above or below 15%. </span><span style="font-family:"Arial","sans-serif";color:#1F497D"></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D">I sense you angling for some additional ‘benefit’ to accrue to a stove that produces biochar. The test only reports what happens, it does not have opinions on what the products are. The mass of char is already recorded (has been for ages) but it was not reported. The only difference is to report it. At the moment the WBT uses the mass of char, not the carbon content.</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D"> <b>[RWL4: I think you probably can get the carbon content from the bomb calorimetry tests on all (?) input and output wood/biomass and char quantities. The important point is that they (Jetter, Still etal) already do calculate and use the <u>energy</u> in the char (which includes the important impact of hydrogen). I am only asking that they also report that ENERGY number separately - since many people are interested in that number. Weights and carbon content are important - but not as important as energy, when the IWA group divisions depend so strongly on energy, not carbon contents, ete. If that means I am angling for something, I plead guilty. <br></b></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D"><b> I take it you disagree with my above sentence about distinctions in reporting 4.2.2 results above and below 15%? You don't want that? You want what difference?]</b><br></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D">I am tightening that definition a little to counter the possibility that ‘cheating’ may be seen with respect to high ash fuels like palm fronds and rice hulls. If it is being ‘rewarded’ as a biochar or charcoal fuel producer, ash can’t be slipped in as a qualifying product.</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D"> <b>[RWL5: I guess you are suggesting that test 4.2.2 reporting is too loose. I don't see that at all. Ash is now getting zero credit for anything.]</b><br></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA">The reason I am being careful is that the formula for fuel efficiency is tilted slightly towards char making stoves in that they are not ‘fully punished’ for using slightly more fuel provided the char production rate is high enough. The mechanism is to give a fuel efficiency (heat energy in the fuel to heat in the pot) then require that char making stoves achieve that % plus the rate of char produced. For example if the target is 30% fuel efficiency, and a stove makes 20% char by dry mass calculation, it will have to have a <i>heat transfer efficiency</i> (not a <i>fuel efficiency</i>) of 30+20 = 50% in order to be accepted. This is slightly advantageous to the char maker in terms of fuel consumption. At a 25% char production </span><span style="color:#1F497D;mso-fareast-language:EN-CA">rate it is an advantage (a forgiveness) of 10% of the fuel consumed.</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA"> <b>[RWL6: Hmm "fully punished". Hmm</b></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA"><b> My understanding is that the efficiency number has been and still is the ratio of pot energy divided by (input fuel energy minus char energy). I do not believe it is as you describe. I believe this formula is slightly tilted away from (is not fair to) char-making stoves - probably because hydrogen values are left out. But I am accepting that formula. I only want to also let people know how much energy is in the char. That number is already being calculated.<br></b></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA"><b> In your description above, you seem to be using 20% char by weight directly in an equation for energy ratios. Makes no sense.]</b></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA">If anyone needs a more stringent explanation of this I can provide it.</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA"> <b>[RWL7: I need it - given to the whole list. With the specific equation numbers from the 4.2.2 procedures with which you disagree. Example faulty calculations are needed, We want to be sure we punish where appropriate. Ron]</b><br></span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA">Regards</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA">Crispin</span></p><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="color:#1F497D;mso-fareast-language:EN-CA"> </span></p></div></div></div><br>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br>stoves@lists.bioenergylists.org<br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br>http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org<br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br>http://stoves.bioenergylists.org/<br><br></div></body></html>