[Stoves] WBT test results: metal grate with rock bed and conical pot skirt

[K McLean]

SNV just released the attached test results that I find very exciting.

Compared to an open-fire cookstove without modifications:

46% less firewood - metal grate under rock bed
42% less firewood - conical pot skirt.


SNV performed Simplified Water Boil Tests (SWBT) which only tested thermal
efficiency, not emissions.

*Metal Grate and Rock Bed*
The first test was a modification of rock beds alone.  Last year, SNV's
SWBT showed a 31% improvement in fuel usage by adding a rock bed to an
unmodified open-fire cookstove.  In this new test, SNV added a metal grate
under the rock bed and elevated the grate by a few very small rocks.  With
the metal grate and rock bed, fuel saving jumped to 46%, compared to the
unmodified stove.  This is a simple modification that can be made and sold
for well under 1 USD.

*Conical Pot Skirt*
A conical pot skirt directs the hot gases of an open-fire cookstove to the
cookpot.  It is easy to make and inexpensive to make, probably around 1
USD.  SNV's SWBT found that it reduced fuel usage by 42%.

The conical pot skirt has limitations.  It may not work well with
three-stone.  (We are working on other pot skirt designs for three-stone.)
In SNV's configuration, the skirt was custom made to the pot with a 1cm
gap.  Further testing is needed to determine the amount of efficiency lost
when used with a smaller pot, and therefore a bigger gap.

[image: Drawing - Conical Skirt on Metal Bar Cookstove.jpg]

We next need to test with rock bed, metal grate and pot skirt.  I hope
we'll find the fuel efficiency is improved by more than 60%.


Thank you,
Kevin

*Kevin McLean, President*
*Sun24*

*https://sun24.solar <https://sun24.solar>  Sun24 Cookstoves Overview
<https://docs.google.com/document/d/1ZryS7gQ1q3zKLZPM2KcXdtIHbOYQp4PbloPqMvrlZ5Y/edit?usp=sharing>*
*Tampa, Florida, USA*
*+1 (813) 505-3340*
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