[Stoves] corn cobs and char?

[Crispin Pemberton-Pigott]

Dear Nolbert and All

We too found that the ready availability of cobs at least some of the time created an opportunity for people to use what was not considered 'fuel' to cook. 

In Swaziland there is a small programme running for some years to give an improved stove (Vesto) to child-headed households. The stove can use a variety of biomass that others do not consider 'fuel' so it is lying around. 

Children generally are not skilled managers of a fire so they tend to use too much fuel and tend to make smokier fires than adults. Because cobs are light they tend not to burn long, of course, but overall the heat is sufficient to cook. 

We received a report that one of the reasons the children liked having an improved stove (apart from the smoke reduction) was the speed of lighting. It takes so long to light an open fire that they did not cook anything (like tea) before going to school. If the stove lights rapidly they can do that. 

Speed of lighting is an important social acceptance factor for an ICS. Quantifying it is not so simple but recording the time from ignition to boiling a small quantity of water is one method. 

Regarding the seasonal nature of the cobs, David Hancock (the famous) said around Harare people used 8 different fuels during the year as they became available. He designed the Tsotso Stove to be able to burn all of them. An essential element of that design is preheated secondary air. After 29 years it is still one of the most fuel-flexible combustors available. It is in the public domain. 

Regards
Crispin
From BB9900

-----Original Message-----
From: Nolbert Muhumuza <muhumuza at gmail.com>
Sender: "Stoves" <stoves-bounces at lists.bioenergylists.org>
Date: Wed, 14 Aug 2013 10:48:38 
To: Discussion of biomass cooking stoves<stoves at lists.bioenergylists.org>
Reply-To: Discussion of biomass cooking stoves
	<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] corn cobs and char?

Hello ALL,

I just picked 4.5 bags of corn cobs from a local farmer near Kampala
who was going to burn them. We shall use them for our cooking needs at
AWAMU plus carrying out tests.

Yes they have a lower density than wood, but if/when available they
are reasonable fuel for TLUD stoves and a convenient substitute to
wood. I have been to two farming communities (in Hoima and Kamuli)
that found our Quad stoves amazing because they were able to use
readily available corn cobs for cooking, therefore women and children
didn't have to go scavenging for firewood for some days.

The trick is corn cobs need to be packed vertically into the fuel
chamber in order to give the cooks a longer burning duration.

Nolbert.

2013/8/14, CHRISTA ROTH <stoves at foodandfuel.info>:
> Ron, we did try corn-cobs, at Stove camp in Honduras in 2011 (see photos
> taken by Jorge Espinosa below) and in Malawi:
> they are a reasonably predictable fuel good in a natural draft TLUD, but
> need a wider chamber (the unit below had 20 cm diameter).
>
> in southern Malawi we found that maize cobs were available at farmers level
> only during a short period of time, especially if people shell the maize
> shortly after harvest and keep or sell the maize in shelled grain form.
> availability depends on land-holding size. in our old project area it is
> down to 0,3 ha per household, so the maximum people will harvest will give
> enough dried cobs to be used during the period of a month or two.
> for other fuels the wider fire chamber was giving too much flame, so we did
> to pursue this option further.
> but there is potential where the landholding sizes and harvesting methods
> fit, especially if farmers store the maize on the cob and then shell as
> needed.
>
>
> Am 13.08.2013 um 20:54 schrieb Ronal W. Larson <rongretlarson at comcast.net>:
>
>> List:
>>
>>   Anyone have any data on using corn cobs in char-making stoves?  The
>> supply would seem to be large and likely low cost..
>>
>> Ron
>> _______________________________________________
>
>
> wide TChar filled with dry corn cobs
>
>
>
> pyrolysis stage
>
>
>
> glowing embers after end of pyrolysis, retained in the lower part of the
> TChar to keep cooking
>
>
>
>
>
> the burn was not intended for char-saving, but maximize energy use
>
>
>
>


-- 
Nolbert Muhumuza

President & Chief Operations Officer
Awamu Biomass Energy Ltd.
P.O. Box 40127, Nakawa
Kampala - Uganda.

Mobile: +256-776-346724
Skype: nolbertm
www.awamu.ug

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