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</o:shapelayout></xml><![endif]--></head><body lang=FR link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Frank,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thank you, sincerely, for exploring ways to improve protocols, for frankly discussing about ways to solve the problem. This is the discussion that needed to happen.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>« </span></i><i>Do you think they will come out the same? That the time it takes, the amount of fuel used, the PM2.5, quality of finished food, etc. etc. <o:p></o:p></i></p><p class=MsoNormal><i>When all the variables are controlled. »<o:p></o:p></i></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I don’t know. In the case you describe, are all the existing variables really controlled?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>But what you say seems plausible.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Not being an engineer or a researcher, I cannot tell.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Engineers or researchers, for example on this List, could answer that. Their answers will have to be backed by good arguments, and if they conclude that the protocol you mention is scientifically valid and allows for a good prediction of the performance on the field, then I might be convinced. If I am convinced, I will support that.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If I am not convinced and major issues remain to be solved, then I will recommend against it.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Just like I did for the WBT.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The question would also be: would your protocol allow to solve the issues of the WBT, and how:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Symbol'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><i><span style='font-family:"Calibri","sans-serif";color:#365F91'>« the (WBT) protocol prescribes to test the stove for a fixed combination of burn sequence (high-power and low-power) and pot dimensions. This limits the test relevance to just that particular setting: when any variation of these parameters which deeply affect the system performance is introduced, results may significantly differ.</span></i><o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:Symbol'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><i><span style='font-family:"Calibri","sans-serif";color:#365F91'>uncertainties related to temperature reading and vaporisation in the boiling region lead to high variability between test replicates. In order to improve the reliability and replicability of the tests, the latest version of the protocol includes the section “Changes to Testing Conditions to Improve Repeatability”, which refers to different fuels and pot characteristics. However, eventual changes involving other parameters (pot insulation and maximum water temperature), which deeply affect test variability, are not mentioned. Such problems give evidence of an unsolved conflict between the declared purpose of the WBT (viz. to be a design-phase test, not intended to be representative of real-use performance), and a general tendency to use the results form WBT as a significant means to select the most appropriate cooking stove for a given context. A lot of debate has been made around formulation of metrics, primarily on thermal efficiency (Table C3), which is often interpreted as the most immediate and distinctive stove performance parameter. Studies from Bailis et al. highlighted how relying on WBT thermal efficiency outputs, regardless of the relative importance of high and low power cooking tasks among the target population, can lead to misleading interpretations. Furthermore, Zhang et al. and Jetter et al. questioned the scientific meaningfulness of thermal efficiency at simmering. Indeed, this phase is characterised by highly variable steam production, which represents a heat loss in the energy balance but positively contributes to the efficiency value in the actual formulation of thermal efficiency.</span></i><o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:Symbol;color:#1F497D'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><i><span style='font-family:"Calibri","sans-serif";color:#365F91'>Finally, some unsolved issues concerning statistical significance of data are worth mentioning. WBT 4.2.3 includes “Statistic Lessons for Performance Testing”. The appendix specifies that the minimum number of test replicates for each model of stove should be three, although it is reported that this number of replicates is not necessarily sufficient to determine a stove performance within a certain confidence interval."</span></i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If the chosen cooking task include boiling, wouldn’t it be a problem? Does boiling means the same for an American master student in engineering and an Indian cook?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Would your protocol work also with a Rocket Stove?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks again for being willing to discuss technical questions on alternative protocols.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>Xavier<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>De :</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Frank Shields [mailto:franke@cruzio.com] <br><b>Envoyé :</b> vendredi 8 septembre 2017 16:59<br><b>À :</b> Xavier Brandao<br><b>Cc :</b> Discussion of biomass cooking stoves<br><b>Objet :</b> Re: [Stoves] Back into action<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dear Xavier,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>A single Question:<o:p></o:p></p></div><div><p class=MsoNormal>If, for example, Paul Anderson sent a Champion TLUD to the lab along with a bag of pellets. And also sent stove and pellets to a Receiving Community. And they were instructed to do the following:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>1) Make sure pellets are certified for US certification to meet the same specs.<o:p></o:p></p></div><div><p class=MsoNormal>2) Fill the stove with pellets, tap three times then fill to the line.<o:p></o:p></p></div><div><p class=MsoNormal>3) Both combustion chambers (stoves) are the same<o:p></o:p></p></div><div><p class=MsoNormal>4) use the same utensils<o:p></o:p></p></div><div><p class=MsoNormal>5) cook the same way<o:p></o:p></p></div><div><p class=MsoNormal>6) complete a similar task determined by an agreed upon measure<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Do you think they will come out the same? That the time it takes, the amount of fuel used, the PM2.5, quality of finished food, etc. etc. <o:p></o:p></p></div><div><p class=MsoNormal>When all the variables are controlled. <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><div><p class=MsoNormal>If you answer Yes - that is proof the system (can) work. <o:p></o:p></p></div><div><p class=MsoNormal>If you answer No - then Cecil please take over. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>If the labs that were doing the testing goes out of business or changes to testing something different due to lack of work and we loose them. We will then be really starting over when we come around to needing them. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>If you answer Yes to above then we need to start finding ways to control the six groups of variables.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>There is no jumping ahead to the field, no shortcuts. We need to do the work. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Regards<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Frank <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></body></html>