[Stoves] WBT disagrements

Thu Jan 11 12:06:57 CST 2018

Dear Kirk,
No worries!
We all are very involved and dedicated to stoves, so it is normal that
sometimes, conversation gets heated up a bit.
Cheers,
Xavier

Le 11 janv. 2018 5:37 PM, "Kirk H." <gkharris316 at comcast.net> a écrit :

Xavier,

I had asked a neutral question to get information and felt that I was being
treated as a having taken sides against those who disagree with the WBT.  I
felt under attack.  I see that I have treated you unfairly and I apologize.

Kirk H.

Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
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*From: *Xavier Brandao <xav.brandao at gmail.com>

*Sent: *Thursday, January 11, 2018 4:05 AM
*To: *'Discussion of biomass cooking stoves'
<stoves at lists.bioenergylists.org>
*Cc: *gkharris316 at comcast.net
*Subject: *RE: [Stoves] WBT disagrements

Dear Kirk,

*“I had to fight tooth and nail with you and Xavier to get tid-bits of
information.“*

I don’t feel it is very fair. I tried my best to answer all your questions,
at length, and provide you information. As I told you first when you
replied to me off-list, I very much prefer to discuss on-list, as we can
all respond and clarify the parts that are not clear. It is good that you
posted this message to the List.

Can you please quote where you think I was not willingly providing
information to you?

This was my answer to your questions off-list:

*“**Are the sensors, filters, and computer graphs included in the
disagreements ?  That is a yes or no question.*

*No, they are not included in the disagreements by the studies.*

*They are nevertheless included in the disagreements by Crispin. Note that
Crispin criticizes the Aprovecho equipment, the PEMS and LEMS, he says it
is not reliable, and he brought evidence on the List.*

*Your question is normally, answered. Do you think it is answered? If not,
why?**“*

*“**According to these two sentences, you are including the sensors and
filters (which measure the CO, CO2, PM and PM 2.5), in the WBT dispute.**“*

*No, I didn’t include the sensors and filters which measure the CO, CO2, PM
and PM 2.5.*

*I included the CO, CO2, PM and PM 2.5 results. It is not the same.*

*So, the sensors, filters, and computer graphs are not criticized by the
studies that say the WBT is unreliable. They do not say the unreliability
comes from that. The unreliability comes from the metrics, statistical
approach, calculations. That does not mean the sensors, filters, and
computer graphs have been proven reliable. They have simply not been the
concern of the studies. *

*Kirk: you cannot isolate the instruments from the WBT.*

*What testing protocol does one use the reliable instruments with? The WBT,
or any other testing protocol.*

*One cannot use the instruments alone, can he/she? One has to follow a
procedure.*

*You could for example ask: « is the water included in the disagreements?
Is the pot? ».*

*No, like the instruments, they are not. But they are integrate to the
protocol. They cannot be dissociated.*

*The CO, CO2, PM and PM 2.5 results are obtained by using the sensors and
filters (not disputed) with the metrics and calculations and statistical
approach (disputed).*

*When you mix a healthy ingredient with a poisonous ingredient, you get a
poisonous recipe.*

*(sensors and filters) X (unreliable metrics and calculations and
statistical approach) = unreliable results.*

*It is the same for a car. A car dashboard may work well, as well as the
steering wheel and the clutch. But if there is a major engine failure, the
whole car doesn’t start. It will not matter that some part of the car work
well: the whole system is not reliable.* “

I don’t see what else I could have done to explain. I also provided you
again all the links to the studies about the WBT issues. You really have to
read them.

Kirk, you said:

*“I also believe in different standards for different purposes.“*

An utterly unreliable standard serves no purpose. A broken tool serves no
purpose at all. It can bring no good. As Philip says, a clock that doesn’t
tell the time doesn’t help anyone.

*“Perfection is not always needed.”*

We are not talking about being perfect. The WBT is not “not perfect”: it is
absolutely broken. No testing protocol is perfect, but the WBT is the only
one being that unreliable.

*“**The WBT does very well for what I need.  It tells me if a change in the
stove is helpful or not.  Whether or not it is perfect science is not
important for my interests.“*

It actually isn’t helping you, even if it is not easy to see.

It is actually really important for your interests, if you want to make
stoves that perform well.

*“I use it because it is available for me in a lab, whereas the other
protocols are not.”*

They are available, right now. They have always been. They are available
here:

https://drive.google.com/drive/folders/0B5rmmRmIsdlnQlRQX3A1cXVOQ3M?
usp=sharing

You asked me what were the labs performing the alternative tests, and at
what costs, as I said to you, I am collecting the information and will get
back to you.

Why do you think they are not available to you where you are?

Like a WBT, it doesn’t need much equipment to perform a CSI test. You could
perform it at home probably.

If I don’t forget anything, I think the equipment you need is:

   - A thermocouple connected to a measuring device for determining the
   water temperature in the cooking vessel
   - A ruler or tape measure for measuring the dimensions of the cooking
   vessel
   - A scale of 30 kg capacity with 1 gram resolution for measuring the
   masses of the cooking vessels and water loads
   - A stopwatch

What do you think is currently preventing you from doing a CSI test?

Best,

Xavier

*De :* Stoves [mailto:stoves-bounces at lists.bioenergylists.org] *De la part
de* Kirk H.
*Envoyé :* mardi 9 janvier 2018 20:12
*À :* Discussion of biomass cooking stoves
*Objet :* Re: [Stoves] WBT disagrements

Crispin,

I think your question was appropriate and the answers were hopefully
helpful.

No, you don’t deserve credit for being helpful.  I asked my question and
instead of answering it you projected your agenda into me and proceeded to
answer your own projections, not my question.  Without an answer from you I
had to make a guess.  You didn’t like my guess and became angry and in that
anger actually gave me a partial answer.  You proceeded to push your agenda
using me as a pawn, but not fully answering my question.  I had to fight
tooth and nail with you and Xavier to get tid-bits of information.  Finally
I had enough tid-bits of information to assemble a coherent answer.  The
credit is mine for fighting for an answer.

Kirk H.

Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
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*From: *Crispin Pemberton-Pigott <crispinpigott at outlook.com>
*Sent: *Tuesday, January 9, 2018 2:13 AM
*To: *Kirk H. <stoves at lists.bioenergylists.org>; Discussion of biomass
cooking stoves <stoves at lists.bioenergylists.org>
*Subject: *Re: [Stoves] WBT disagrements

Dear Kirk

I think your question was appropriate and the answers were hopefully
helpful. There are many lab based systems of ‎measurement and sometimes
only a few measurements are necessary to make great progress in improving
an existing product.

Something that can be separated ‎is this: Aprovecho is not 'the WBT'. What
they do and how they do it is not dependent on using the WBT which is
merely a fixed test sequence with a set of measurements and calculations.

Philip's comment about the WBT telling you whether or not the stove is
improved is most pertinent. If the test didn't tell you how it performed
the first time, getting a different wrong answer later may, or may not, be
helpful. This is the crux of the problem.

Tuning a stove requires making refined measurements, not generalizations. A
series of small, say, 3% improvements can result in a 12-15% improvement in
fuel consumption or power change time, or turn down ratio. If the test
cannot reliably tell you the change ‎for better or worse is 1% vs 4%, the
results are guiding you by chance.

A very carefully done experiment must, not should, deliver reproducible
results‎. Prof Lloyd has I think been the most specific on this point, much
more than most commenters. As an experimentalist not familiar with small
stoves, he was expecting that stove performance tests would deliver the
same sort of replicability as other physics experiments. The WBT doesn't do
that because of the conceptual errors embedded in what it measures, when,
and how it calculates the outputs.

On the face of it, why should the calculations make a result variable? Dean
once posted here that if there is a mistake that is applied to every test,
then it is not important.

The difficulty is that the mistakes manifest errors unequally in different
stove types, additional to the variability created by conceptual errors.
Prof Lloyd was forced to abandon the WBT in favour of a method without
those errors in order to continue his work.

Thank you for participating offlist in the discussions. ‎Xavier are I are
discussing the preparation of a spreadsheet with a number of tabs, one each
for different versions of the WBT and CCT. Putting in the lab info from a
test will create copies of the test on each tab with the different
calculations so the outputs can be compared. I think we will be able to
find 12 versions of the calculations, maybe 15.

We can also prepare one tab without the errors. This will be the formulas
to be applied that are developed from first principles as per the HTP/CSI
where the requested metric is calculated from only the necessary
measurements made to achieve it.

Given the limitation of the test sequence itself,, high, high, low power,
it would give 'an answer' that could be used to compare the performance of
two slightly different versions of a stove, or different fuels, pots,
ambient temperature and so on.

In South Africa, any kerosene stove tested in Johannesburg or similar
altitude must also have an emissions test conducted at a coastal location.
Similarly in reverse. The performance on such a pair of tests must be
highly reproducible.

Such a comparison sheet can be very helpful for convincing the casual user
that only the corrected version should be relied upon. Failing that, we
must retire, as there are always going to be those who will not make the
effort to understand the technicalities of the field in which they choose
to dabble.

After that comes the issue of contextuality. If the WBT with 'standard
wood'‎ is used to develop a stove that will be used to simmer soup burning
dung, there is no hope. It would be like perfecting a gasoline engine for
89 octane fuel then operating it with diesel oil.

All stoves are used in some context so the assessment will be most
relevant, even for internal metrics for sub-systems, if the test conditions
are relevant to the expected pattern of use. The WBT is advertised as a
'cooking simulation'. That's OK. Pick and report.

Regards

Crispin

All,

I recently asked a question about whether the disagreement with the WBT
included the sensors, filters and computer graphing as well as the water
boiling portion of the overall test.  I have received several responses
from Crispin and Xavier (some off list).  From all that was said by them I
have assembled an answer:  The sensors, filters and computer read-outs are
part of the WBT, but not part of the disagreement with the WBT.  So this
disagreement is with a portion of the WBT test, not all of it.  Also, I
believe that Crispin has a second disagreement that questions whether some
sensors and setups are able to provide accurate read-outs.  I believe that
this is a legitimate concern for scientific study, however I also believe
in different standards for different purposes.  Perfection is not always
needed.

This is an acceptable answer for me.  It is not pro or con to the WBT or
any protocol.  My question was intentionally neutral.  I just wanted to
know the extent of the disagreement.

My position on the WBT remains neutral.  I use it because it is available
for me in a lab, whereas the other protocols are not.  The WBT does very
well for what I need.  It tells me if a change in the stove is helpful or
not.  Whether or not it is perfect science is not important for my
interests.

I believe that Aprovecho (ARC) plays an important part for wood stove
development and education and I remain a supporter.

Kirk H.

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