[Stoves] Pebble bed three stone fire

Fri Nov 8 09:15:00 CST 2019

Dear Nikhil

Your obsession about our obsession may be answerable by referring to the cook who said she was buying half as much fuel (150 K Shillings) per day. Perhaps she too is obsessed but about saving money.

I tried carefully, in detail, to assess whether the change in the fire permitted her to use an alternative fuel which might save additional money, as ins the case in Kyrgyzstan. She said, "No."

She just spends half the money she used to.

Regards
Crispin
From: ndesai at alum.mit.edu
Sent: November 8, 2019 4:00 PM
To: crispinpigott at outlook.com
Cc: cec1863 at gmail.com; stoves at lists.bioenergylists.org
Subject: Re: [Stoves] Pebble bed three stone fire

Crispin:

Please get over this "save the fuel" mania. What does it mean - either financial saving if a bank gives a 10% real interest, or some ecosystem protection that is context-specific and computing value to which (and for whom) is an extremely demanding task.

The discussion sparked by "rocks" was informative, just that we know the basic combustion science of air flows for centuries. Why did it take so long for people, even experts, to figure this out? Deliberate neglect of options that don't allow pretense of science?

I remember a couple of years ago, Ron had gone to some conference in a US midwest university where a professor (of Indian origin, I forget the name) had presented research on a cheap grate introduced in some communities of Rajasthan. Looks like nobody paid attention to such research, even for "fuel saving". Understandable; such solutions don't advance the bureaucratic interests of EPA and the career interests of its contractors.

N
------------------------
Nikhil Desai
(US +1) 202 568 5831
Skype: nikhildesai888

On Fri, Nov 8, 2019 at 7:35 AM Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
Dear Nikhil

You ask good questions.

Africa is the place but not exclusively. I have a document showing the sums.

It has been certified by the SNV lab in Cambodia using their modified water boiling test which was developed by GERES to try to correct some problems in the WBT4.

The comparison is made with the performance of a three stone fire. The TSF is still very popular.

The technology is not limited to three stones. They are experimenting with adding rocks (which increases breathing through the coals on the bottom) is all manner of stoves.

Consider the rocket stove. It suffers from a high char production rate (as a fraction of fuel fed) and the change really improves performance in terms of high power, lower fuel needed and lowered emissions.

Charcoal stoves seem to be improved if they are not the latest designs. At present we don't have to know why the rocks work, it is enough that they do.

There is a very high retention rate. That alone indicates that it makes a perceptible difference and that it is beneficial.

I talked to two users and they agreed it saves a lot of fuel. About half, she said.

Until future notice, all stoves should be tested with stones added under the fuel. See what happens. Maybe it's good. Maybe it's always good.

Let's see. Nothing could be cheaper.

As to what would Berkeley do, they will sell stove use monitors.

Regards
Crispin
From: pienergy2008 at gmail.com<mailto:pienergy2008 at gmail.com>
Sent: November 8, 2019 2:33 PM
To: crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>
Reply to: ndesai at alum.mit.edu<mailto:ndesai at alum.mit.edu>
Cc: cec1863 at gmail.com<mailto:cec1863 at gmail.com>; stoves at lists.bioenergylists.org<mailto:stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Pebble bed three stone fire

Crispin:

Cute. Glad. Please give some context when possible:

1. Where?
2. Is this measured and certified under ISO protocols using WBT? If so, it can be compared with the tens of other products.

Taking your "3 million" at face value, SNV success is to be celebrated. I don't really know how many of the "3 billion" people do all their cooking and water heating with literally "three stones" - nobody knows, pretense notwithstanding - but it is always good to find such examples of innovation. Unfortunately, I have had no first hand experience of cooking with wood on three stones.

Just think - if rocks can reduce emissions, the price of aDALY could be driven down to $0.05 per capita per year! What would Berkeley do?

N

------------------------------------------------------------------------
Nikhil Desai
(US +1) 202 568 5831
Skype: nikhildesai888

On Thu, Nov 7, 2019 at 9:38 AM Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
Dear Friends

This is a photo of the three stone fire with a set of stones in it, and a clay grate as an aeration device.

In the past 8 months about 3 million people have adopted this as a fuel saving and emissions reduction "device".

The retention rate (continued use) is in the high 90's % range. It's effect is obvious and basically free.

This is a demo presented by SNV after the ISO meeting.

Regards
Crispin
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