[Stoves] farmed fuels

[Stoves]

Andrew, 
I suppose your assumption is correct. The two times I saw the emptying of the char everything was pyrolysed and no uncarbonised cobs left.  They tend to be dry and as they are rather light-weight, they carbonise very easily. The fuel container is sheltered as it sits inside the oil drum and thus it gets really hot inside. 
Whenever I visited the farm in those months of cooking I asked the cooks again and nobody reported smoke as an issue.
As primary air is restricted, the char can’t continue to burn, also the cooks were instructed to empty the char out for cooling once they had served the food. 
That is as good as I can guess

Best regards
Christa

> On 23. Jun 2019, at 23:56, Andrew Heggie <aj.heggie at gmail.com> wrote:
> 
> On Sun, 23 Jun 2019 at 22:41, Ronal Larson <rongretlarson at comcast.net> wrote:
> 
>> 4.  .  “”foodandfuel” is almost certainly a creation of Christa Roth. (See   http://foodandfuel.info/foodandfuel/. And especially.
>>      http://foodandfuel.info/foodandfuel/Archive_files/HERA%202011%20micro-gasification%20manual%20V1.0.pdf
>> 
>> Maybe Christa wrote this specific list entry, but if not, could we hear more about “foodandfuel” in Malawi.  Seems like some excellent stove work going on there.
>> 
>> 5.  My questions on this particular stove:
>> a.  What char yield is obtained?  25% possible?
>> b.   Can you supply the dimensions for the components.  (Diameters and heights). A sketch would help (wanting to see both primary and secondary ari flows)
>> c.  Of particular interest is your use of a skirt - which we don’t see enough of.  How important for efficiency gain?
>> d.  Is there primary air control?   Might the primary air receive preheating?
>> e.  This looks like you must be cooking for better than free  - zero cost fuel and a salable (biochar) product.  Can you estimate the months of operation to pay off the cost of the steel parts?  (Over a 3-stone fire competition).
>> f.  Has anyone done a simple water boiling test?  Might you be at Tier five?
>> g.  Is anyone making these for sale and at what price?     How many in use now?
> 
> Might I add a questionabout how the flame self extinguihes at
> ~40minutes after lighting without  any smoke? Is this because the cobs
> are so dry and thoroughly pyrolysed that there are no volatiles left
> to become PICs and the char then burn cleanly until extinguished?
> 
> Andrew
> 
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