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

[adam u partner]

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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adam + partner
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