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<div class="moz-cite-prefix">Dean,<br>
<br>
Although you point out that the WBT was designed as a lab tool, it
has been converted into a system of evaluating cookstoves. It
has become the basis of the Tier structure. Even if not yet
"enforced" as a Tier structure for granting funds or for
purchasing stoves, the mere suggestion that the results of a well
conducted WBT (as currently configured) should be the basis for
any, ever, future, possible judgment of stove qualities is
becoming (in my opinion) totally unacceptable.<br>
<br>
Also, the "lab tool" is really not the WBT. The tools are the
equipment for making measurements. And I sincerely LIKE the
capabilities of the LEMS for measurements. But when the data are
processed in questionable ways, or the results are combined in
ways that give a false sense of accuracy as is implied in the WBT
procedures, that is not appropriate and needs to be changed
significantly.<br>
<br>
Personally, I like the concept of a set of tests that can be done
with simple water in a pot. And we need all of the data to be
available. Otherwise, the "gaming" of the methods is
facilitated. For example, the "time to boil" is certainly
clocked during the testing, but is not reported. Therefore, a
small stove that is operated at a low power during the initial
phase (to bring to boil) can get some better scores on CO and PM
and efficiency of fuel consumption. But if it is reported that
the time to boil is 2 or 3 times longer than (for example) for a
larger version of the same stove, it can be clear that the cooks
in the households will NOT want such as slow stove. <br>
<br>
I look forward to the analyzes of "gaming" (I do not want to call
it cheating) that you and Sam are preparing. I suspect that the
list will be sooooo long and soooo important that there will be a
outcry for "truth in testing."<br>
<br>
Furthermore, there is evidence (at least very strong hearsay) of
the LACK of correlation between WBT results and stove performance
in the field (at least for many stoves). This makes the WBT
unacceptable as the basis for the Tier system of evaluations.<br>
<br>
Paul<br>
<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
On 2/19/2015 3:31 PM, Dean Still wrote:<br>
</div>
<blockquote
cite="mid:CA+tShZvsLnqGLmsc1q68FDViPTJmAU=EEHu1WSbvLQ8eE=rPZA@mail.gmail.com"
type="cite">
<div dir="ltr">Dear Paul,
<div><br>
</div>
<div>I'll try once again.</div>
<div><br>
</div>
<div>The WBT was designed to be a lab tool.</div>
<div><br>
</div>
<div>The CCT and KPT are used to make stoves that please cooks,
meet requirements in use.</div>
<div><br>
</div>
<div>The instructions in the WBT, CCT, KPT plainly state the
intentions.</div>
<div><br>
</div>
<div>Aprovecho uses the CCT when we want to design a stove with
the local cooks using their foods, pots. They operate the
stoves. The cooks should design the stove.</div>
<div><br>
</div>
<div>The WBT teaches how to improve stove technology. Two very
different uses.</div>
<div><br>
</div>
<div>All Best,<br>
</div>
<div><br>
</div>
<div>Dean</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Feb 19, 2015 at 1:06 PM, Paul
Anderson <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Dear Jiddu, and to all who share the concerns about
errors in testing of stoves.<br>
<br>
Your comments are greatly appreciated. Well said. As
we make progress on these topics, the comments will be
continually refined for clarity of expression, and will
be the composite work of too many people to be
individually named. Thank you.<br>
<br>
To know of your credentials as a theoretical physicist
is appreciated. There could be people with credentials
on both or all sides of the discussion. But you can
talk to other physicists much better than I can. In
debates (and courtrooms) both sides like to have their
expert witnesses. Thanks for stepping forward. <br>
<br>
I especially like your comment that shows your
convictions:<br>
<blockquote type="cite"><font face="Arial">I find myself
in the position where I have to tell my company to
produce stoves with lower rating because it will be
better for women that we build them for.</font></blockquote>
That is worth re-reading and repeating!!!<br>
<br>
As I get further into this topic, I am realizing that
invalid metrics must be STOPPED. I do not yet know how
much they have hurt various stove designs, but I can see
no way that such metrics have been of any positive
value. ------<br>
<br>
----- Oh, and if some stoves are benefited by such
inaccurate metrics, and if the manufacturers know that
they have made claims based on faulty testing, THAT
would be truly reprehensible. <br>
<br>
It is fast becoming (in my opinion) the time when the
defenders of the status quo about the three Low Power
measurements in the WBT will need to speak up with some
quite convincing arguments.<br>
<br>
Paul<br>
<br>
<pre cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a moz-do-not-send="true" href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a>
Skype: paultlud Phone: <a moz-do-not-send="true" href="tel:%2B1-309-452-7072" value="+13094527072" target="_blank">+1-309-452-7072</a>
Website: <a moz-do-not-send="true" href="http://www.drtlud.com" target="_blank">www.drtlud.com</a></pre>
On 2/19/2015 1:56 AM, Jiddu Broersma wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Dear All,
<div><br>
</div>
<div>First,</div>
<div>Paul, thank you for keeping the conversation
going with great intentions. Much appreciated.</div>
<div> <br>
</div>
<div>I have been a quiet follower of the stovelist and
I just caught up on the simmering discussion. I
believe it is a necessary discussion.<br>
</div>
<div><br>
</div>
<div>I would like to share my opinion. It is one from
the perspective of a stove manufacturer and a
theoretical physicist. <br>
I do this purely to contribute to the discussion.
Although I will formulate my opinion direct with
strong language, I want to assure you all that I
value everyone's opinion equally.</div>
<div>Now, I will jump straight into the low power
metrics.</div>
<div><br>
</div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial"></span><b>Simmering</b><br>
As has been explained, simmering is a 'zero work'
task, it does not have an efficiency. Evaporating
water and overcoming heat losses require work, they
can have an efficiency. However, is anyone
interested in knowing the efficiency of evaporating
water? Or is anyone calculating how much energy is
lost from the pot?</div>
<div><br>
</div>
<div>Either way, simmering is only a term that we will
hopefully agree on. Most important is to understand
the meaning of the metrics that are calculated: Low
power specific fuel consumption, Low power CO and
Low power PM.</div>
<div><br>
</div>
<div><b>Low Power Specific Fuel Consumption</b></div>
<div>From the WBT sheet I find that (equation)</div>
<div>Low power specific fuel consumption = (weight
fuel consumed * calorific value of fuel ) / (weight
of water remaining * minutes of simmering * 1000)</div>
<div>To explain in steps: </div>
<div>
<ol>
<li>Weight of fuel consumed divided by minutes
simmering is the burn rate.<br>
</li>
<li>If we multiply this by calorific value we get
the energy released by the combustion per
minute. Let's call this the 'energy rate'.<br>
</li>
<li>If we divide this weight of water remaining we
just divide it by a random number that has no
meaning. Keeping more food/water hot does not
require more energy. (I believe it does the
contrary, because volume grows faster than
surface when you increase quantities)<br>
</li>
</ol>
</div>
<div>-> We have the energy released by the
combustion divided by a random number.</div>
<div><br>
</div>
<div>If we wish to calculate some kind of efficiency
number we require useful energy (into pot) divided
by used energy (from combustion). What we have
calculated is nothing close to this.<br>
</div>
<div><br>
</div>
<div>We could possibly calculate the energy into
evaporation and heat loss from the pot, but we have
no interest in this. </div>
<div>Hence, a simmering task can't give us a useful
efficiency type of number!</div>
<div><br>
</div>
<div>That was me as a physicist, as a employee of a
manufacturer I am concerned that stoves are unfairly
compared. Because the system can be manipulated to
gain better results by using a pot with larger
volume capacity and higher insulating properties. </div>
<div>Also another big issue is that more efficient
stoves can have lower rating at the same power
output. I'll explain by example (as others have done
before me):</div>
<div><i>Two stoves are equal except that one has
better heat transfer efficiency. When they both
run at the lowest power possible (which is the
same power for both), the one with the better heat
transfer efficiency will have likely evaporated
more water because more energy went into the pot.
Do to more evaporation it will end up with a
rating that is worse!</i></div>
<div><br>
</div>
<div> <span
style="font-stretch:normal;font-size:13px;font-family:Arial"></span><b>Low
power Emissions</b><br>
<span
style="font-stretch:normal;font-size:13px;font-family:Arial">Both
PM and CO are given in </span></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial">weight
/ (minute * liters of water)</span></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial"><br>
</span></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial">Similar
breakdown:</span></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial">Weight
of emissions per minute is straightforward.</span></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial">Dividing
this by number of liters in the pot is simply
dividing the emissions by a number of your choice
(the liters you fill in the pot). It has no value
to stove rating.</span></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial"><br>
</span></div>
<div><font face="Arial">Generally I think that weight
of emissions per minute is not a bad metric.
However, simmering is not a task that can be
compared fairly between two stoves because it is
not a specific task! If we can't compare the way
two stoves simmer because we know nothing about
the useful energy that went into the pot we are
not allowed to compare the results because it
means nothing without enough information.</font></div>
<div><span
style="font-stretch:normal;font-size:13px;font-family:Arial"><br>
</span></div>
<div><font face="Arial"><b>Wrap-up</b></font></div>
<div><font face="Arial">The list of complications that
result from these invalid simmering metrics goes
on. Please read again Crispin's and </font><span
style="color:rgb(0,0,0);font-size:12.8000001907349px">Philip
Lloyd's comments for a more comprehensive list. </span></div>
<div> <span
style="font-stretch:normal;font-size:13px;font-family:Arial"></span><br>
<span
style="font-stretch:normal;font-size:13px;font-family:Arial">Worst
is that many manufacturers are optimizing their
products using the WBT and that stoves are not
actually improving in the field. The WBT can
result into the production of bad stoves for
millions of already suffering women! </span><font
face="Arial"><br>
</font></div>
<div><font face="Arial">I find myself in the position
where I have to tell my company to produce stoves
with lower rating because it will be better for
women that we build them for.</font></div>
<div><br>
</div>
<div><font face="Arial">It is not a matter of right or
wrong, it is a matter of how we stimulate the
production of stoves that are really improving
lives. </font></div>
<div><font face="Arial">My opinion is that we need to
review the meaning of metrics at fundamental
level. </font><span
style="font-family:Arial;font-size:13px">(Ie.
Boiling and simmering are not scientific ways of
describing a state of cooking for stoves).</span></div>
<div><br>
</div>
<div>Due to the differences in opinion in the stove
world, I believe an external review (scientific:
engineers, physicists, mathematicians) would be the
most suitable option. The review could simply
explain the physical meaning of all calculated
results. </div>
<div><br>
</div>
<div>Best regards,</div>
<div>Jiddu</div>
<div><br clear="all">
<div>
<div>
<div dir="ltr"><font
style="background-color:rgb(255,255,255)"
color="#666666"><b>Jiddu Broersma</b></font>
<div><font color="#666666"><b>Technology and
Organization Officer</b></font>
<div>
<div><br>
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