[Stoves] Pebble bed three stone fire

[Crispin Pemberton-Pigott]

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
Sent: November 8, 2019 2:33 PM
To: crispinpigott at outlook.com
Reply to: ndesai at alum.mit.edu
Cc: cec1863 at gmail.com; 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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