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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;mso-fareast-language:EN-US">Dear Paul<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;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:windowtext;mso-fareast-language:EN-US">I think I can answer the question you pose but let’s take this sequentially because if we are making progress towards a common understanding
about how to create useful metrics, I do not want to lose momentum.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">></span>The char that is produced in a TLUD stove is removed and is NOT used in any burning that relates to the TLUD stove that made it. The char comes out. Where it goes is not an issue here.
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Good start. We are agreed that downstream applications have no effect on the rating of performance of the stove in question. A stove hoes not get a better
rating because of something you promise to do with the char. The ‘benefit’ of char has to consider the char itself, not what might be done with it. External activities might be considered together with the stove, but that refers to a
<i>system</i> of which the stove is a part. <o:p></o:p></span></p>
<p class="MsoNormal"><br>
<span style="color:windowtext">></span>However, your reply still does not address my question about char values (weight or energy) being used in all those other stove testing methods.
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">None of the stove test methods which report the performance of the stove’s fuel efficiency, emissions, and power, for example, have anything to say about char
produced. There is a very good reason for this and you will have to admit that it is legitimate: no one
<i>asked</i> about this matter before (char deliberately produced) so there are no metrics describing the ‘benefit’ of the char in any stove test method.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">></span>Your comments about big systems was interesting:
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span style="color:windowtext">>></span>As far as I know, in general all tests of thermal performance such as power stations, fixed boilers, heating stoves and cooking stoves
<i>in the formal sector</i> treat solid resides with energy content remaining as a 'mechanical loss'. That is the definition of a mechanical: unburned fuel that could in theory have been burned but was not, and is left at the end.
<o:p></o:p></p>
</blockquote>
<p class="MsoNormal"><span style="color:windowtext">></span>But, really, in the situation of cookstoves, what the formal sector with billions of dollars does is only of passing interest.
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Engineers will disagree. All these systems can be described using the same toolbox of standard terms. Size had nothing to do with it, conceptually. Stoves
can be just as complicated as steam engines.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">></span>"Mechanical loss" is something like the smear of food remaining on a dinner plate after a hearty meal. Just wash it off, dry the plate, and life goes on.
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Not so in all cases, it can be a very large loss and we have to quantify it. High CO is a large chemical loss – many %. Carbon in the ash of a locomotive is
an important fuel input to the brick making industry. Locomotives are optimised for size and power, not fuel efficiency. There is a lot of carbon in the ash. People buy it as a cheap fuel.<o:p></o:p></span></p>
<p class="MsoNormal"><br>
<span style="color:windowtext">></span>However, in the cookstove world, where char is INTENTIONALLY CREATED AND SAVED, it is not a mechanical loss.
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Well here we have to accept that there are standard definitions and they are accepted as correct. Anything that a stove cannot burn and appears in the form
of a gas is a chemical loss <i>for the purposes of rating the performance of that stove</i>. Maybe the stove is designed to produce a high CO gas as an output, perhaps it is also cooking on heat that is available anyway. The CO constitutes a chemical loss
if rating the cooking efficiency only. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">If the loss appears in solid form, it is by definition ‘mechanical’ as far as rating the cooking. I understand that the word ‘loss’ is painful when you are
trying to create char, but for cooking purposes is it not helping the cooking efficiency if the fuel is not combusted. You cannot expect that the cooking efficiency will be rated higher if there is a mechanical loss that is small, but the efficiency will be
higher if the loss is large. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">It is important, nay critical, to remember
<i>what</i> the metric is reporting: the performance as a cooker. Full stop. If you want another metric to explore the char and its nature,
<i>no problem</i>! Create one, but the cooking efficiency will not be improve just because the mechanical losses are recovered for other uses. We can go over this again and again, but the cooking efficiency will not be improved.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Now, there are those who say the WBT or char energy number is the ‘thermal efficiency’. That is a bad choice when we are talking about energy that has not
been thermalised. Usually, when looking at the system as a whole, the <i>potential thermal energy</i> in the fuel is compared with the
<i>delivered thermal energy</i>. Some called that the thermal efficiency even though if you look closely there are mechanical and chemical losses. The problem with the term is the rather obvious fact that some of the energy was not thermalised. “Energy Efficiency”
is better because the term includes all forms of energy. The energy efficiency of a solar cooker consider radiation and thermal energy. No problem.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">></span>It is a purposeful gain, something that is desired.
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">That is why I asked of you considered it a ‘benefit’. It
<i>is</i> a benefit because it is something you want to create. No problem. That does not affect the cooking efficiency, right? The stove consumed the fuel, cooked a bit, and delivered some
<i>wanted char</i>. No one is worried by its being wanted. They <i>are</i> worried about claiming that the stove didn’t used the fuel that was consumed to make that char, because it did. They are also worried about claiming that if the stove didn’t release
the energy in the fuel it consumed, the energy efficiency should be rated higher. Why? Because it misleads people into thinking the stove used less fuel than it actually did. Numerous examples from the field confirm this to be true of WBT ratings – about
100% of them.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">You are looking for a way to fairly report the energy needed for cooking
<i>and</i> the energy contained in the char. You can do that, but you can’t call it the cooking efficiency because it is not. Are we agreed? It has to be called something else because the cooking efficiency is energy delivered to the pot over energy available
in the fuel consumed. There is fuel consumed that is turned into char. We all agree with that. You even gave carbon contents as an example. That char energy was not delivered to the pot, and it is not available as fuel in that stove, as you pointed out.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Because char is a benefit, and cooking is a benefit, they both have to appear in a numerator if the efficiency of ‘doing it’ is to be reported. Let’s call
the fuel energy A, the cooking energy B and the char energy C. Space heating energy I will call D. There are three benefits to be reported.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking efficiency is benefit 1 and it is
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">B/A [1]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Char energy is benefit 2 and it is
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">C/A [2]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Space heating energy is benefit 3 and it is
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">D/A [3]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">What you are asking for is some rating of the stove that combines B and C as benefits. No problem. The formula will be
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">(B+C)/A [4]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Others may want the combined cooking and heating efficiency. That is
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">(B+D)/A [5]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Others may want all delivered energy benefits:
<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">(B+C+D)/A [6]<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">What you do not have is a
<i>name</i> for the sum of the cooking and char benefits. One thing is obvious: you are not going to find the correct answer by subtracting the char energy from the fuel energy. Why? Because it gives the wrong answer!
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">We need some numbers now for the demonstration:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking energy 1 MJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Char energy 2 MJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Heating energy 3 MJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Fuel energy 8 MJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">The efficiency if retaining the fuel energy as char energy is a legitimate calculation – formula [2] from above:<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">2/8 = 25% char energy retention in the recoverable portion<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">I have to add ‘in the recoverable portion’ because the total in the solids is more than 2 MJ. Of course what is a ‘recoverable portion’ has to be defined in
the protocol. Let’s move on.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking is 1/8 = 12.5%<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Char is 2/8 = 25%<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Heating is 3/8 = 37.5%<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking benefit + Char benefit is (B+C)/A<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">(1+2)/8 = 37.5%
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">This is the same as the sum of the two efficiencies calculated separately. This is the metric you are seeking. Give it a name. You
<i>cannot</i> call it the cooking efficiency. The cooking efficiency is 12.5% and doesn’t change just because you made some char (or not).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Let’s look at the WBT formula:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking benefit + Char benefit is
<b><i>not</i></b> (B/(A-C) <o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">1/(8-2) = 16.7%<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Yet, this is the formula Ron is clamouring for. It grossly under-represents the sum of the cooking work performed and the energy content of the char produced.
Why would you want to misrepresent the value of the stove? It has delivered as co-benefits 37.5% of the fuel energy. Why would you want it reported as 16.7%? It is not true! Why is it not true? Because the char energy was deducted from the denominator instead
of being added to the benefits in the numerator. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Remember that the WBT formula was intended as a proxy for the heat transfer efficiency. It was never intended to report the benefits of char making, which
needs an ‘energy retention efficiency’ metric.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Let’s move on:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking benefit + char benefit + heating benefit is (B+C+D)/A<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"> (1+2+3)/8 = 75%<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cooking benefit + char benefit + heating benefit is
<b><i>not</i></b> (B/(A-C-D)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"> 1/(8-2-3) = 33.33%<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">></span>Or at least not to be used as a penalty, as a way to make the stove appear less desirable.<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">It is not a
<i>penalty</i>. It is a <i>benefit</i> and can be reported as such. But is it <i>
not</i> deducted from the denominator because the denominator represents the energy in the fuel needed each time to run the test. There is no getting away from that. You want the correct answer, not an incorrect one that does not represent what is in the energy
paths.<o:p></o:p></span></p>
<p class="MsoNormal"><br>
<span style="color:windowtext">></span>BUT TO GIVE CREDIT FOR CHARCOAL AS "UN-USED ENERGY" IS NOT AN ERROR<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">It
<b>is</b> if you do not calculate it properly! There has never been a problem to work out the energy, mass and usefulness, properties and acidity and density of char produced. But the energy in the char cannot be deducted from the energy in the fuel needed
to create the char in such a way that it gives the impression that the fuel was not needed, or, more importantly, that it under-reports the combined efficiency of the co-benefits which in the example is 37.5%. You don’t want that reported as 16.7% (half its
real value).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">></span>Unless better evidence is provided, please do not use the calculations involving charcoal (subtraction in the denominator) as a major arguement against the WBT.<br>
<br>
<span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Char making is not a major argument against the WBT. The mere existence of the formula and the way the resulting number is presented as a proxy for fuel consumption
is condemnation enough. But there are literally scores of other issues with the WBT which also have no bearing on char. The biggest of all is the high uncertainty of the result. It can’t be used to place stoves on tiers when the uncertainty is considered,
which is has to be if it is to stand up to analysis as a test method. Don’t worry about the WBT. It is discredited without char production issues.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">You need to worry about a proper descriptive name for a cooking+char efficiency metric. It is an efficiency because it is a ratio of energy benefits to energy
cost.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">></span>I would greatly appreciate some knowledgeable comments about how THOSE OTHER TESTS handle the issue of charcoal that is left in the stoves. Is there
some agreement between those many tests? <span style="color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">I think I have addressed that above. Virtually all test methods ignore char remaining. They do that because they treat all solid residue as a mechanical loss.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Agree on a name for your cooking+char efficiency number. We will use it. Don’t waste your time calling it the thermal efficiency. That term is allocated several
times over. Remember it doesn’t cover all the energy in the solid residue, only a portion of it, the wanted and retained and recovered bit(s).
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Crispin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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