[Stoves] (no subject)

Mon Oct 28 00:29:04 CDT 2019

The main reason for these savings is that the initial load of charcoal matters: This effect was documented very well by Sam Bentson and the rest of the team from Aprovecho many years ago: 
https://www.researchgate.net/publication/257434335_The_influence_of_initial_fuel_load_on_Fuel_to_Cook_for_batch_loaded_charcoal_cookstoves <https://www.researchgate.net/publication/257434335_The_influence_of_initial_fuel_load_on_Fuel_to_Cook_for_batch_loaded_charcoal_cookstoves>

If only we could convince people to buy the right size charcoal mbaula we would not need to use fillers like rocks and additional grates to displace the charcoal and have people start with a smaller initial load. 

Best regards
Christa

Am 27.10.2019 um 14:59 schrieb K McLean <info at sun24.solar>:

Here is a report from Zambia <https://docs.google.com/document/d/167i50oweyfe23bRMnDSeJwlu0eM4IgTek6IO2C6JPes/edit?usp=sharing> indicating that the rock bed and second metal grate improve the efficiency of the Zambian mbaula (all-metal) charcoal jiko by 41%.  Cooking time is also greatly reduced.  While these testers have no training, their results are consistent.

This is such a simple modification that dissemination could be very rapid.  I hope some of you can try this. 

On Thu, Oct 10, 2019 at 1:37 PM K McLean <info at sun24.solar> wrote:
Listmates,

Has anyone tried this?

We seem to have significantly increased the efficiency of charcoal jikos by putting a bed of rocks on the jiko's grate and putting second metal grate on the rock bed.  The charcoal goes on the second metal grate.   2-3 cm rocks work.  It works in all metal jikos and clay jikos that we've tested. 

Our testing is early and unscientific, but consistent.  25-50% less fuel used.  Here are three reports.  The Sierra Leone report has good photos at the bottom.
Sierra Leone <https://drive.google.com/file/d/12MvBKjxq6PCGCcCHAjSYSeVXXvl7jWjD/view?usp=sharing>
Uganda <https://drive.google.com/open?id=1zQIY49E1vrfjYl7t5V_shvw70d67QirGWUrbW51tDxo>
Kenya (very few rocks) <https://drive.google.com/open?id=1MPwHCwKEVqJvuybKB5Yj39nr8fbcopBP>
(The report authors are untrained and not native English speakers.  Especially the Kenya report contains many errors. Please focus on the consistent final conclusion that a rock bed and second metal grate significantly reduce firewood usage.)

This may be a very low cost, very easy way to greatly improved the efficiency of charcoal jikos.  I'd like to hear if there is already a body of work on this.  Here is my rough drawing:

<20191010_133359.jpg>

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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