----- Original Message -----
From: Kevin
To: Discussion of biomass cooking stoves
Sent: Thursday, October 24, 2013 12:42 AM
Subject: Re: [Stoves] Shields E450c as a way to test char-making stoves(attn:
GACC testers)
Dear Ron
Do you believe that wood burning stoves will be rated for fuel consumption, but
that "char making stoves" will be rated for
fuel consumption minus the energy remaining in the char?
Kevin
----- Original Message -----
From: Ronal W. Larson
To: Crispin Pemberton-Pigott ; Discussion of biomass
Sent: Wednesday, October 23, 2013 2:16 PM
Subject: Re: [Stoves] Shields E450c as a way to test char-making stoves(attn:
GACC testers)
Crispin cc stoves
Fine.
Ron
On Oct 23, 2013, at 11:10 AM, [email protected] wrote:
Dear Ron
We'll at least this time you are not putting words in my mouth, you are
just misunderstanding what I write and as far as I see, deliberately so.
If you have no more questions I will be happy to move on.
Regards Crispin
>>Q10>>>
From: Ronal W. Larson
Sent: Wednesday, October 23, 2013 12:47
To: Crispin Pemberton-Pigott; Discussion of biomass
Subject: Re: [Stoves] Shields E450c as a way to test char-making
stoves (attn:
GACC testers)
Crispin and list
#1. You have added only extraneous material re naming, China, kilns. You
did not at all address the issue of treating char-making stoves fairly.
#a. Same response. You did not address the topic of differentiating
between char-making stoves. Apparently you are happy that your money making
stove in Indonesia will receive a report that says nothing about the char
produced?
#b1 Same response. You have a typo "for a that stove" that precludes a
definitive answer since I don't know whether to strike "a" or "the". I
continue to believe that the present approach being used by Jim reports
everything you ask for - and always has. The only new material I know about I
am delighted with - the amount of char and the energy in the char is
specifically now provided. It was always there, but hidden. Char-making stove
people couldn't be happier with this small change in reported results.
#b2 -i You write about the formula A/(B-C): "... it has been misleading
people ever since it was introduced"
I agree. - but for opposite reasons than you. It undervalues the
production of char. I am willing to let it ride, since my preference is also
being shown.
- ii You write: " Char? Fine, if it too can be burned as fuel. If
it is not usable, it is not fuel. Same as ash as far as that stove is
concerned." I am sorry that you don't see how unfair this statement is to
char-making stoves -- where people (including you) can make money on the char -
whether used as fuel or put in the ground. You are taking income away from
the poorest with your stance.
- iii Your last sentences: The WBT was changed and that was the major
point of Jim’s recent webinar to which you posed a number of questions and
which he answered repeatedly.
[RWL: And I was happy with all the answers.]
I am again answering that same question.
[RWL: With answers different from Jim's]
The fuel consumption considers whether or not the remaining fuel is fuel
for that same stove. If it is not, it shall be considered consumed.
[RWL: You are (I think) the only one saying this should be the
rule. Certainly no-one who thinks making char in a stove is better
economically and environmentally - regardless of where it ends up. Of course
for climate reasons I want it to go in the ground, but I started on this topic
in the early 1990s just to save trees. Char-making stoves can do both, but
since char-makig stoves are more efficient and cleaner, char-using stoves are
on their way out.
End of short story. Take it up with Jim if you do not agree with this
reality.
[RWL: I see no need to. I think Jim is handling "reality" correctly
and has already said so on this list several times.]
On Oct 22, 2013, at 5:56 PM, "Crispin Pemberton-Pigott"
<[email protected]> wrote:
Dear Ron
>Crispin and stoves list (again ignored - why?)
1. The "game" I am playing is to ensure that charcoal-making stoves
are treated fairly. Saying that existing char at the end of a run has been
"consumed" is not fair.
How do you suggest we term the fuel that enters a stove once, each time
the stove is operated through a burning cycle? Should that be the fuel
consumed? The fuel needed per cycle? The fuel use? The fuel demand? Give it a
name and let’s see how it flies.
We are speaking of course of raw biomass in this case. Whatever biomass
goes into a stove, per cycle, drawn from the available supply, and which needs
to be drawn again the next time, needs a name.
In the strict sense of the word ‘consumed’ it has been consumed as far as
that stove is concerned. In another sense, from an outside perspective which
can see additional uses for that remainder, whether it be ashes or char, it has
‘produced something’. No problem. One can view it that way, but it will not
change the raw fuel demand for a new cycle unless some of it is fuel to that
same stove. There is no other practical way to communicate to people the amount
of fuel a stove requires to be harvested and provided each day.
In China they have a test that runs for a month. A stove is installed and
cooked upon each day for a month. The amount of fuel it consumes during that
month is calculated. Then they know what the fuel consumption really is. If
there is a huge pile of char left afterwards, they do not consider that an
‘efficiency’. I can’t say I am surprised.
If you are in the char making business, you still have to consider how
many cubic metres of trees are needed each day. That is the raw fuel
consumption of the char making kiln. The char produced is not a raw fuel
efficiency, it is the output efficiency of the char making process. No problem.
We both owe a duty of care to the people buying and promoting stoves to
correctly report the amount of biomass that is needed to fuel the stove per
cycle or per day or per month.
2. Under a) - I repeat my original claim - you have no test in mind that
will differentiate between char-making stoves. If char is there, it has not
been "consumed".
Well you can read the above again if you like. If there is char remaining
that is not fuel for the stove from which it came, it comes from fuel which the
stove consumed. Word it as you like. I thought you would be asking for a report
on the char production efficiency with a rating on the energy content per kg
and the % volatiles. That would make sense if you wanted to sell it for income.
I am hoping to do exactly that in an area of Indonesia where there are many
candle nut shells. It makes really good charcoal fuel when burned in a TLUD
which people can sell for income.
When assessing the fuel consumption of the TLUD that makes that char, we
will get the mass of fuel consumed per cycle, the energy content and rate it
accordingly. Another stove that burns the same fuel and cooks the same amount
and produces no char will consume a lot less raw material. All we are doing is
reporting how much the stove consume per cycle.
3. Under b) - The key sentences are your final two: The direct cause
is that the more char produced, the less fuel was claimed to have been
consumed, which is clearly untrue. That is why the WBT was changed." If
char exists, the claim of less fuel is "clearly true", not "clearly untrue".
My claim is related to the amount of raw biomass needed to be put into
the stove each time it is used. Your claim is to view the char remaining as
fuel. This may or may not be true for a particular stove. If that char is fuel
for a that stove, then the char can be credited as unburned fuel. The point is
to tell the prospective buyer what the raw fuel consumption is.
Further, the use of the formula A/(B-C) goes back at least to VITA days
and is in there today. On this main point under dispute, the WBT was NOT
changed (thank goodness). Or if I am wrong, please give a cite.
Yes it does go back that far and it has been misleading people ever since
it was introduced. It was written on the basis that the desired measurement
was not the raw fuel consumed each cycle, but the efficiency with which the
heat was developed in the fire and transferred to the pot. That is why it was
called (in those tests) the ‘heat transfer efficiency’. It isn’t really the
heat transfer efficiency, but it was given that name. The heat transfer
efficiency is a useful number for stove designers. When making changes like pot
to stove clearance the number will change. But it is not and never was the fuel
consumption figure, even for the fry fuel consumption, because the consumption
depends on what happens to the fuel remaining. If it is long sticks that can be
burned tomorrow, fine, it is unburned fuel. Char? Fine, if it too can be burned
as fuel. If it is not usable, it is not fuel. Same as ash as far as that stove
is concerned.
The WBT was changed and that was the major point of Jim’s recent webinar
to which you posed a number of questions and which he answered repeatedly. I am
again answering that same question. The fuel consumption considers whether or
not the remaining fuel is fuel for that same stove. If it is not, it shall be
considered consumed.
End of short story. Take it up with Jim if you do not agree with this
reality.
Regards
Crispin
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