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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;mso-fareast-language:EN-US'>Dear Kirk and Paul<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>There were three numbers provided for power, the low the high and the test-high.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>It was mentioned that there was a scale under the stove (which is a very good idea) and that readings were taken per 5 minutes (which is a pretty long interval).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Was the high power a maximum during the test phase, or the average over the phase? If it was the average then it should be presented like that because the phase includes an ignition. If it is the maximum firepower, that would not be the average including ignition.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>If I say an electric stove has a 5 kW element, that is the maximum input power. The cooking power is the input power times the heat transfer efficiency. That is pretty straightforward.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>So I wondered if the scale readings were used to determine the maximum power by using the burn rate, or if the power was determined in some other way. If it was scale-based, it means it is the average of the 5 minute intervals. If it was based on the scale, what energy content was applied? Was it the WBT sheet LHV (compensated for moisture? Was it the As Received, Ash-Free heating value? Was that value char-remaining-compensated to correct for the energy not released? <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>The determination of the firepower of a stove is not nearly as easy as getting the cooking power, which in any case is what people experience when they use it.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>At the moment I do not have a clear picture of what that 6 kW refers to, and as mentioned already, we don’t know the cooking power (delivered energy). Planning to introduce a design to a certain area will require taking a pretty good guess that the product is in the right cooking power range.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Because we don’t’ have the test spreadsheet with all the input numbers it is hard to know these answers, hence all the questions.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Dr Nurhuda provided a photo of a pot as proof that the PM is low for his latest stove. That is not a ‘test result’ in the numerical sense, but we can assume it must be pretty good.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Kirk provided some numbers from a WBT conducted at Aprovecho, which have emissions per MJ and per unit time etc. But we don’t have the numbers for the total MJ or the total time so we can’t tell a whole bunch of things we need to know to evaluate the performance or suitability. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>The best we could do is to share the official test spreadsheet so the missing metrics are available to those who need them. I cannot select a stove design based on an emissions per MJ if I don’t know how many MJ it is capable of delivering. I can <i>rate</i> a stove I have already selected using that metric.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>I can’t select a stove design based on a heat transfer efficiency if I don’t know how much heat was involved. Similarly, the firepower combined with other metrics could be used to determine cooking capabilities but only if I am quite sure what that firepower number refers to: peak, average, smoothed 3-minute peak, and so on. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>What do we want to know?<br>Cooking power total.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Cooking power per sq cm.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>System efficiency for some known and relevant task, expressed as the “Energy Efficiency”<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Fuel flexibility.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Cost.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Durability.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Pot holding capacity.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Pot stability (when stirring).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Tilt stability.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>PM mass per delivered MJ (used together with the cooking power)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>CO mass per delivered MJ (ditto)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Note: the Energy efficiency is used as a proxy for relative fuel consumption to compare stoves. Very importantly, it must not refer to the heat transfer efficiency or any proxy of it. That is an internal relationship, and we want the black box version of the fuel consumption.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Most of these numbers can be calculated from the information recorded in a WBT spreadsheet.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><strong><u><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>Paul</span></u></strong><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>,</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:10.0pt'><span style='font-family:"Calibri",sans-serif'>Kirk and Crispin,<br><br>I BELIEVE I understand Crispin's question of "How is the 6 kW power measured?"<br><br>I think the answer is that it is based on the amount of energy released in the measured time to bring the water to boil (that being the high power time-period, but the calculation has nothing to do with the increase in water temperature. And that the energy measurement is based on the energy of the weighed fuel (adjusted for moisture content), and giving "credit" for the energy that is in the remaining charcoal.<br>Does that make sense? </span><o:p></o:p></p><p class=MsoNormal style='margin-bottom:10.0pt'><b><u><span style='font-family:"Calibri",sans-serif'>Yes</span></u></b><span style='font-family:"Calibri",sans-serif'><br><br>Kirk and Aprovecho testing personnel: Is that correct?</span><o:p></o:p></p><p class=MsoNormal style='margin-bottom:10.0pt'><b><u><span style='font-family:"Calibri",sans-serif'>I’m not sure what you mean here. At Aprovecho it is correct. At Berkley it was the Berkley lab Engineer, experienced tech and students. It has been a good and fun experience working with very bright people at both Aprovecho and Berkley.</span></u></b><span style='font-family:"Calibri",sans-serif'><br><br>Crispin: Were you expecting some other answer? What other way might be used?<br><br>The Kirk Harris Wonderwerk TLUD stove with Strata combustor will certainly be a featured item at the 5-day Stove Camp on 15 - 19 August at Aprovecho. Even if you cannot attend, you can give inputs and questions to Kirk (and to other attendees) via this Stoves Listserv.</span><o:p></o:p></p><p class=MsoNormal style='margin-bottom:10.0pt'><b><u><span style='font-family:"Calibri",sans-serif'>Yes</span></u></b><span style='font-family:"Calibri",sans-serif'><br><br>Comment: Kirk points out that this is a research device. And that actual manufacturing with his advances is something that needs additional discussion and work. THIS issue of how to put it into production will be an important topic at Stove Camp and here on the Listserv.</span><o:p></o:p></p><p class=MsoNormal style='margin-bottom:10.0pt'><b><u><span style='font-family:"Calibri",sans-serif'>Yes, thank you<o:p></o:p></span></u></b></p><p class=MsoNormal style='margin-bottom:10.0pt'><b><u><span style='font-family:"Calibri",sans-serif'>Kirk H.</span></u></b><span style='font-family:"Calibri",sans-serif'><br><br>Paul</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><blockquote style='border:none;border-left:solid black 1.5pt;padding:0cm 0cm 0cm 4.0pt;margin-left:3.75pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>----- Original Message ----- <o:p></o:p></span></p></div><div><p class=MsoNormal style='background:#E4E4E4'><b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'> <a href="mailto:psanders@ilstu.edu" title="psanders@ilstu.edu">Paul Anderson</a> <o:p></o:p></span></p></div><div><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>To:</span></b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'> <a href="mailto:stoves@lists.bioenergylists.org" title="stoves@lists.bioenergylists.org">Discussion of biomass cooking stoves</a> <o:p></o:p></span></p></div><div><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>Sent:</span></b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'> Wednesday, June 08, 2016 6:34 AM<o:p></o:p></span></p></div><div><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'>Subject:</span></b><span style='font-size:10.0pt;font-family:"Arial",sans-serif'> Re: [Stoves] kgharris stove test<o:p></o:p></span></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>Kirk and Crispin,<br><br>I BELIEVE I understand Crispin's question of "How is the 6 kW power measured?"<br><br>I think the answer is that it is based on the amount of energy released in the measured time to bring the water to boil (that being the high power time-period, but the calculation has nothing to do with the increase in water temperature. And that the energy measurement is based on the energy of the weighed fuel (adjusted for moisture content), and giving "credit" for the energy that is in the remaining charcoal.<br><br>Does that make sense? <br><br>Kirk and Aprovecho testing personnel: Is that correct?<br><br>Crispin: Were you expecting some other answer? What other way might be used?<br><br>The Kirk Harris Wonderwerk TLUD stove with Strata combustor will certainly be a featured item at the 5-day Stove Camp on 15 - 19 August at Aprovecho. Even if you cannot attend, you can give inputs and questions to Kirk (and to other attendees) via this Stoves Listserv.<br><br>Comment: Kirk points out that this is a research device. And that actual manufacturing with his advances is something that needs additional discussion and work. THIS issue of how to put it into production will be an important topic at Stove Camp and here on the Listserv.<br><br>Paul<br><br><o:p></o:p></p></blockquote></div></body></html>