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</o:shapelayout></xml><![endif]--></head><body 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'>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'>>></span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>We need to know the Carbon and Hydrogen content to determine the heat content without having to resort to a bomb calorimeter which is time consuming even if inexpensive. The heat potential can be calculated pretty well if you have the H2 and C content.</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><b><i><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'>[*]How much char-ash left may depend on fuel type, moisture and stove performance or when the cooking (or task) was complete. But I would think the test method for determining energy left would not be concerned with these. Only make-up of the char-ash mix. Some chars and ash have a lot of carbonates. I’m sure the carbon comes from the biomass but not sure how that calculates in the energy left. A calorimeter I think would show none with CaCO3 but was energy used to create it? And we (our lab) would need a grant to move into research not directly related to projects we hope to make a profit on. And there are so many. </span></i></b><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><b><i><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></i></b></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The only question is how much energy remains in the fuel that could be released by burning it. It can be done by analysis, but is most easily determined with a bomb calorimeter. I hope we can constrain the error by learning what some typical values are for fuels and stove, but make no mistake, the stove has a strong influence on the nature of the char remaining. It is not just about the fuel type. What looks like char might be mostly ash 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'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>>>D</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>r Penn Taylor (we can call him that now) outlined one method for determining the accuracy of two WBT’s. There were several steps or points that led to the total. Each point is an error that needs to be constrained. If a test method has fewer error points, the final result is more precise. <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><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'>[*]Looking for a limiting factor and correcting it then on to the next is the way to approach it as he is doing. <o:p></o:p></span></i></b></p><p class=MsoNormal><span style='font-size:14.0pt;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 test methods need to be examined one step at a time to see what the errors are. First eliminate all errors that are unnecessary. Second determine what question is being asked and don’t provide unneeded answers that create additional errors.<o:p></o:p></span></p><p class=MsoNormal><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'> [*]</span></i></b><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'>…</span></i></b><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'>This is the same issue as with many of these complex problems. Like determining if biochar improves crop production by adding to one field and not to the next. One will always be different than the other but relating it to biochar when there are so many other variables… They need to look at what biochar will, or will not, do and stop there. Then the field trial can be designed around one or two of these improvements biochar makes and it might show better crop production or $ saving of water or fertilizer. . <o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></i></b></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>You can do multivariate testing if you already know the effect of the fertiliser and water and mulch etc. Randomised trials are designed to uncover previously unknown combinations of effects. Biochar seems to fall into that category.<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'>>></span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>One of the reasons to report the net heat transfer efficiency (the efficiency of the whole system) at different power levels is that not only is it a very useful metric for creating a performance curve of efficiency v.s. power, but it can be done quite precisely with simple equipment. You could easily make a determination within 3% in your lab right now. But you can’t light a stove within 3% each time on different days using a variety of fuels.</span><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><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'>[*]It seems that the ignition stage is the problem in the lab and in the field regarding producing particles. Therefore it seems we should be designing a ‘fuel starter’ made of distillate from the fuel in another operation (or something like that) that when lite will burn fast, clean and pre-heat the stove before the biomass is applied. Like a Richard Stanley briquette made of special material. Perhaps that simple first step could do more to reduce health issues than making improved stoves. <o:p></o:p></span></i></b></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'>I agree that we should pay attention the ignition sequence. Some stoves are very easy to light and there is little skill involved. Others not so. Charcoal stoves usually make a lot of smoke when being ignited but as Peter Coughlin has shown in Maputo, the ignition time can be reduce from 20 to 2 minutes using a sheet metal cone of appropriate dimension. That make a big reduction if PM2.5 emissions and is very convenient for the cook.<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'>>>…</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If a designer wants to know what efficiency the user will experience, the test (or that section of it) has to provide the required information. You lead the rest of your life like that, why not stoves too??<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><b><i><span style='font-family:"Calibri","sans-serif";color:#1F497D'>[*]The buyer will know nothing about stoves and have no idea what to ask for – except the obvious you have states. They will not know what the results mean. Only what we tell them with a rating system or picture diagram of compared stoves. At least that is my experience working with regulators and end users. We need to tell them what they want. : )<o:p></o:p></span></i></b></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 stated purpose for the testing of stoves at the IWA meeting was for ‘informing policy makers’. Policy makers are not your average Joe Public. They are making key decisions about technology selection and training, distribution and marketing support. They cannot be ignorant of the subject. Let’s assume they ‘have a clue’ and then look at the tests. Do the tests accurately reflect future performance for stoves in that tier? They are lab tests. Do we have a history of lab tests predicting field performance? No. Well, perhaps the reason they have not been all that predictive is because the test methods themselves are not accurate, or measure the wrong things, or because the measured things are reported in the wrong fashion.<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'>It does not really matter what the reasons are, but it does matter that whatever we do from now on is legitimate. There is no point saying to a policy advisor, sorry your stove programme failed, but I followed the protocol correctly so it is not my fault. If the protocol can’t give a determination that is helpful, it needs to be updated or replaced. Stoves are not ‘special’ in this regard.<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'>You would not accept a cellphone which can’t make calls is OK ‘because it was lab tested and passed all the tests required’. What is surprising is that so many people think it is not possible to conduct a lab test that predicts field performance. Murphy’s Law says that, “Two units that perform identically in the lab will perform differently in the field.” Well…OK, but at least they are performing in the field.<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'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin<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><p class=MsoNormal><b><i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></i></b></p></div></body></html>