[Stoves] Charcoal versus wood cooking; heat value per volume !

[Richard Stanley]

Adam,
On your return to Nairobi some time, I suggest that you stop off in 
Makweni and wend your way up into Kasikeu location north off mombassa 
road (about 8 - 10 clicks: Vehicle will need relativley   hi ground 
clearance due to some sand and ruts) ,  but then find Mary Kavita of 
the Miumbuni Womens association. She will tell you all about briquettes 
they make locally  (She and about 4 other groups of producers there..).

If that is not convenient, then kindly continue on to Lengatta (just 
past Twiga park) and look up Nick Wood (he runs the go cart track next 
to the Carnivore  as well as a tourist lodge in the Mara). Find out 
about what they are doing ref. hollow core micro enterprise based 
briquette making and find out how ordinary biomass with about 25% 
charcoal fines / dust waste stuff will well outperform charcoal much 
less wood, stove or no stove...Two of these 125 gram briquettes (10 cm 
dia 7.5 cm tall on average) will fit nicely into your mentioned  jiko 
ya kawaida and do the same job quite well.
Or in Kangemi or Kisii of a few dozen more places in nchi ya Kenya, for 
that matter

wako wa umtumishi,

Richard Stanley
www.legacyfound.org


Richard Stanley Legacy Found.org
On Jun 22, 2006, at 2:19 AM, adam u partner wrote:

> Charcoal versus wood cooking; heat value per volume !
>
> I want to make a contribution to these (sometimes useless discussions 
> about heat value per weight between wood and charcoal).
>
> I am just sitting here in a bungalow at the coast of Kenya and my 
> neighbour, a girl starts to cook beans on a charcoal fire. Its 4:00 
> p.m and she fills the charcoal cooker with pieces of charcoal.
>
> The amount of charcoal she fills is determined by the volume of the 
> area between the charcoal grate and the pot support. Let's assume she 
> fills a space of about 1,5 liter with pieces of charcoal.
>
> So my question is- if she would have had the same amount of wood 
> (volume in this case) available, would she have had a left-over of 
> wood?
>
> I doubt!
>
> Charcoal in a charcoal cooker needs no attention once it burns.
>
> Once the pot with cold water is put on the charcoal cooker, she gives 
> her attention to cleaning the beans.
>
> I asked her if she will be adding charcoal later? She said yes.
>
>
> So the question really should be: To boil to 2 kg of water and 1kg(?) 
> of beans, how much charcoal will she be using?
>
> and in comparison, if you give her a heap of wood (equivalent in 
> volume to the bag of charcoal she has) and some kind of improved metal 
> wood stove (a cheap one) how much wood will she be using?
>
> In the case of wood it may be the danger that she is adding more wood 
> than actually is necessary ("the fire might look nice") because she is 
> having a heap of wood.
>
> In the case of charcoal she is also having a heap of charcoal but she 
> will not add too much, because the volume, the space is limited in the 
> charcoal cooker.
>
> So this assumption that 2 /3 of the energy is lost when charcoal is 
> produced is just unfair, if you really look at the integrative aspect 
> mentioned above.
>
> What is really important is the question "how much more (or less) wood 
> would have been used cooking the beans without charcoal!"
>
> I also want to mention that with the newly developed low-cost retort 
> kilns we have a yield between 30% and 42% which puts this aspect of 
> charcoal production also under a different light.
>
> Here is a time schedule of the bean cooking:
>
> 10 minutes: starting to fill charcoal in the cocker. Filling paper in 
> the lower part of the cooker.
>
> 20 minutes: ignition, cooker was put aside into the garden because of 
> smoke in the beginning.
>
> 2 hours 30 minutes beans ready. (Some other girl told me later, 
> cooking of beans takes 4 hours (!)).
>
> (The water with beans started boiling after about 20 minutes when the 
> pot was put in the charcoal cooker.)
>
> Chris ADAM
>
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