[Stoves] Advocacy action: ask the GACC to stop promoting the WBT
Roger Samson
rogerenroute at yahoo.ca
Wed Feb 15 10:18:25 CST 2017
just to add a bit more about Crispins point about using locally available fuels to design stoves....
One of the reason so many stoves don't find user acceptance is that they are designed remotely from the user and their accessible fuels. We use a constructivist approach with end users to construct together a technology that fully meets users needs and available fuels. We did this with our rice hull stove in the rural Philippines 15 years ago and more recently with our clay brick stove in Gambia. We are concerned with performativity at the user level not the published journal results using a sub-optimal stove test and cooking fuels that are not typical of those used by communities.
The opposite approach is positivism, you independently develop the technology from the users, publish the results in journals, and effectively push it on communities through various means like fuel subsidies and free stoves that certain agencies promote.
Douthwaite describes sustainable and unsustainable pathways to technology development. One of the reasons improved stoves are failing is the donors dont understand sustainable approaches to enabling technology innovation.
Read the work of Douthwaite:
http://boru.pbworks.com/f/ag_syst_IPE.pdf
A youtube video on it
https://www.youtube.com/watch?v=wM6mpqTrFLM
and what's supposed to be a good book that I haven't read yet
http://www.amazon.com/Enabling-Innovation-Practical-Understanding-Technological/dp/1856499715
regards
Roger
Roger Samson
Executive Director
Resource Efficient Agricultural Production (REAP)- Canada
Centennial Centre
21,111 Lakeshore Rd.
Ste. Anne de Bellevue, Quebec, H9X 3V9
Tel. 1-514-398-7743
www.reap-canada.com
https://www.researchgate.net/profile/Roger_Samson2
--------------------------------------------
On Wed, 2/15/17, Crispin Pemberton-Pigott <crispinpigott at outlook.com> wrote:
Subject: Re: [Stoves] Advocacy action: ask the GACC to stop promoting the WBT
To: "Stoves" <stoves at lists.bioenergylists.org>
Received: Wednesday, February 15, 2017, 2:39 AM
Dear Frank
Just a quickie:
"4) develop a form to be included with
each stove as to the biomass properties that work best in
this stove."
This is probably backwards and it is
important to get it the other way round: tell us what fuels
are available and characterise them correctly. Then we will
develop a stove that burns it well, in a controllable
fashion, with
the cooking and heating power adequate for the anticipated
tasks.
Yes, I realise that people 'invent a technology' and
then hunt around for a set of fuels it can burn, but that is
technology-centric, not customer-centric.
Tell me about the fuel and the task, and I will tell you
about the stove that can do it. Something like that.
Thanks for the thoughts
Crispin
Dear Crispin,
We have spent years and years and
come up with a list of WBT trying to get some Efficiency
calculation. Who cares? Does anyone out there care about
efficiency calculations? The only possible way that could be
at all helpful is if you add half
the energy of biomass into the combustion chamber you get
the same efficiency value. That is the amount of energy in
the biomass will heat the same amount of water. Due to
changes in air flow, waste heat in the walls, how the fuel
is packed, type and shape
of biomass etc it will never do that. You can’t give a
stove an Efficiency value.
We need to find the properties of
biomass that will work in a combustion chamber. Meaning it
will light, create heat and do a task with approved results.
1) We need a list of biomass properties that make a
difference. 2) we need to develop test
methods to quantify those properties 3) we need a procedure
to test stoves to determine the stoves limits for these
properties 4) develop a form to be included with each stove
as to the biomass properties that work best in this stove 5)
test wild biomass for
those properties and some sort of chart to determine if the
stove will work with that fuel. If it shows it will work
then sell them the stove and be assured it will work and
what handling of the biomass is needed. Whether or not the
people is willing to do
the necessary preparation needed on the biomass is another
separate issue.
When any group is ready to start
working on the list of properties that make a difference and
develop test methods to measure those properties - let me
know. I am now willing to help if wanted but not likely much
longer. I still have somewhat
of a lab to work in.
Aprovecho has claimed many time to have done
exactly that. I challenge this claim. They optimised their
stoves to get ‘good numbers’ on the WBT which does not
report the actual performance.
Sometimes it is similar to the real values, sometimes is it
not. It largely depends on how much char is produced. The
more the char, the greater the over-claim.
I agree with the above - when it
was used to compare stoves. It worked when determining
optimum setup, information that could be used for all
stoves. As for using to compare stoves, that came when the
time was needed for comparing stoves and there
was no other procedure for doing so. There is still no
procedure for doing so. Hats off to Aprovecho IMO.
Thanks
Frank
On Feb 14, 2017, at 9:27 PM,
Crispin Pemberton-Pigott <crispinpigott at outlook.com>
wrote:
Dear
Frank
The
problems with the WBT are more fundamental than you
describe.
It
must be faced, square on, that the WBT calculation does not provide
the efficiency.
The formula is wrong!
If
you create a stove as you suggest, and measure the
efficiency using the WBT, and it says the cooking efficiency
is 40%, you would be happy. Then if you used a different
test like the Chinese
one, it might say the efficiency is 25%. So, which is
it?
I am
telling you that there is a problem with the calculation,
not the concept of testing.
Here
is something practical you can do to prove it: Get a set of
numbers from a stove test, the fuel consumed, the char
balance and so on, water masses and temps. You can invent
one or use
a real stove. Then enter the same set of numbers into the
various versions of the WBT:
VITA
1985
WBT
2.0
WBT
3.0
WBT
3.1
WBT
4.0
WBT
4.1
WBT
4.1.2 of October 2011
WBT
4.1.2 of April 2012
WBT
4.1.2 of June 2012
And
finally
WBT
4.2.3 of 2015.
You
will get 10 different answers.
And
not one of them will be correct because there are systematic
errors in the concepts underlying the calculations plus
errors in the formulas themselves.
‘Perfecting’ a stove using incorrectly
calculated metrics is not going to lead to stove nirvana.
The Indian, SeTAR and Chinese tests all perform the
calculation more or less correctly. The
Indian test uses an inappropriate fuel in that the stove
has to be optimised to that (100% dry) fuel in order to
perform well. No one in India uses such fuel so the stove is
optimised to an inappropriate air pre-heating and air-fuel
ratio. They have been advised
to revise the test.
The
Chinese test uses a very different approach conceptually as
it includes a burn-out phase which raises the reported
efficiency by about 11% of value. That is something applied
to all stoves
and fuels so the result is ‘fair’. There is a small
miscalculation in the efficiency from double-counting. (For
fun, I challenge the readers of this list to find it. It
escaped detection for decades.) It can easily be
corrected. They have been advised to
revise that calculation.
The
WBT contains several important errors. When the IWA text was
proposed, I reviewed it and reported some of these errors to
the committee. For the most part they did not correct the
errors,
marking them as ‘too small to worry about’ and ‘to be
handled later’ and ‘for later discussion’, that sort
of thing. Thus there was public input on the IWA text but
the corrective information was not applied to the
result.
In
the IWA meeting numerous discussions were held on metrics,
names of metrics, ideas about what could be in the document.
A lot of the meeting time was taken up with presentations on
how
the document was prepared. The tiers were presented and as
the numbers were dependent on WBT results, many of us knew
they were unimportant as they would have to change when the
test was corrected. The IWA event was conducted in the
following manner: “We have
already agreed in Lima on what should be in an
international test method so all we have to do is
rubber-stamp it and we can go home.”
That
was of course not acceptable as the Lime event just gave the
WBT 4.1.2 the nod without examining it closely nor
correcting the manifold errors. To get our (South Africa –
6 delegates)
agreement, it was critical to have any test method approved
by external, expert reviewers, which obviously had not been
done before. This text was added and we all voted for it. It
would be quite incorrect for anyone to suggest that we
approved of the whole
content because, for example, the IWA has 9 performance
metrics and the WBT only produced on of them, efficiency,
and calculated that incorrectly. Yet it was the ‘default
method’. With only one metric being produced, and there of
the nine being physically
invalid, there was little hope the IWA and its testing and
tiers could deliver on the promise of ‘better
stoves’.
Consider what happened since: the requirement to have
all test method examined externally
by experts was never implemented
for the WBT. It would of course fail because of the invalid
metrics and the bad calculations.
When
new got to the ISO we were told, “The IWA in ins place and
everyone is using it so all we really have to do is
rubber-stamp it and we can all go home.” That of course
didn’t happen.
Votes were held kicking out all WBT-forms of test and also
the tiers. Let me repeat: the vote by the experts was that
there should be no WBT and no tiers in the
Standard.
If
you find tiers in the ISO standard it is not because the
experts wanted them or voted them to be there. For the IWA
it didn’t really matter because the requirement to have
the test methods
reviewed would have killed any tiers they were based on –
assuming that the IWA was actually implemented, which of
course it was not. People pick the bits they
like.
>The WBT used exact sized, dry and
consistent wood type for the testing to establish the best
gaps, insulation, height and etc. measuring performance of
energy entering a pot of water.
Aprovecho has claimed many time to have done
exactly that. I challenge this claim. They optimised their
stoves to get ‘good numbers’ on the WBT which does not
report the actual performance.
Sometimes it is similar to the real values, sometimes is it
not. It largely depends on how much char is produced. The
more the char, the greater the over-claim.
The
AWBT from GERES is better on that particular metric, even
though it is not perfect. Bottom line: Do not develop a
stove using the WBT. It will mislead you.
Regards
Crispin
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Thanks
Frank
Frank Shields
Gabilan Laboratory
Keith Day Company, Inc.
1091 Madison Lane
Salinas, CA 93907
(831) 246-0417 cell
(831) 771-0126 office
fShields at keithdaycompany.com
franke at cruzio.com
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