[Stoves] Charcoal and Stoves

[Crispin Pemberton-Pigott]

To be of benefit to this group, we should state clearly what is being represented and what is being misrepresented.

If the fuel fed into the fire (“Fuel Fed” being a term I think created by the late Prof Lloyd for the ISO standard) is measured, each time the task is replicated, then the answer is close to what a KPT will report. Sort of the actual fuel consumed.  In the case of the test of Kevin’s rock beds, SNV used the standard WBT formula which does not do that.  It is important to know that it does not. It reports what is really a proxy heat transfer efficiency with energy numbers converted into fuel mass.

Thus, the performance is over-rated.

For those who want to see how this affects real money from real stove projects, have a look at https://impact.sustain-cert.com/document_files/3377 and we will discuss it here.

If you are not familiar with this type of document, it is a good introduction.

Regards
Crispin
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I understood you to mean that the fuel was measured and the char discarded. If the stove is leaving char at the end of a cook but the char is not being accounted for than it shouldn’t matter what you do with the char. Does that make sense? I can see the misreporting problem.

Tom

On Mon, Jan 27, 2020 at 6:53 PM Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
“If the fuel conversion of the stove is based on performance without char burnout then there is no penalty…”

What exactly do you mean by that. I don’t want to misinterpret.

Do you mean if the char energy is subtracted from the fuel energy before converting it to an equivalent dry fuel mass?
Do you mean if the char energy is not subtracted from the fuel energy before converting it to an equivalent dry fuel mass?

This is the essence of the misreporting of the fuel consumption of a stove.  Is it based on the fuel needed to operate, or the energy released and back-calculated to an equivalent fuel mass.

If the fuel was measured and the char discarded, then I understand you to be saying there is no fuel penalty because the char was not affecting the claimed fuel consumption.

Thanks
Crispin


From: Stoves <stoves-bounces at lists.bioenergylists.org<mailto:stoves-bounces at lists.bioenergylists.org>> On Behalf Of Tom Miles
Sent: Monday, January 27, 2020 18:28
To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org<mailto:stoves at lists.bioenergylists.org>>
Cc: stoves at bioenergylists.org<mailto:stoves at bioenergylists.org>
Subject: Re: [Stoves] Charcoal and Stoves

If the fuel conversion of the stove is based on performance without char burnout then there is no penalty for removing residual char for other purposes. In the Lifeline cases cited the uses appeared to be essential activities in the household.

In the biochar case there can be more benefit from the agronomic uses - reduced cash for fertilizer, reduced labor for watering, improved yield, etc. - than for carbon sequestration. Depending on the application and the fuel it may be more practical to make the biochar in other devices but it may be suited to small garden plots.

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