[Stoves] Energy per meal/human measurements was Cooking by conduction - plancha stoves

[Kevin Chisholm]

Dear Jigme
----- Original Message ----- 
From: "Jigme Rangdrol" <rangdrol at turboisp.com>
To: "Stove List" <stoves at listserv.repp.org>
Sent: Saturday, June 17, 2006 11:38 PM
Subject: [Stoves] Energy per meal/human measurements was Cooking by 
conduction - plancha stoves


> The measurement problem is inextricable from culture. It seems reasonable 
> that any real solution will have to be a human based solution not a techno 
> based solution.
> Lanny Henderson's picture of a portion of beans next to a spoon of chips 
> is the best bottom line energy per meal measure I have seen here precisely 
> because it transcends culture and uses a human measurement.

Right on!! The woman who has to trudge into the woods to get firewood wants 
to know: "How many loads of wood do I have to collect to cook for my family 
for a week, if I use Stove A, Stove B, or Stove C?" Clearly there will be 
differenced between Countries, and even within regions within a Country, but 
if there was an average number of "grams of wood per person per meal," this 
should be very helpful to her in selecting a stove that was most relevant to 
her requirements.
>
> There is no consensus and there are in fact no biomass 
> gram/BTU/kg/cal/#%/etc/etc/season/yr calculations that can be done in the 
> field in 90 seconds or less nor any that take all the very very relevant 
> conditions and causes into the calculations in under an hour or five. We 
> cant even get consensus on how to test boiling water.
> PLUS as the stoves get smaller and more technical the differences get 
> smaller and measurements get more exact to be relevant while at the same 
> time they get harder to acquire in the field, more rarefied and less 
> relevant to the end user.
> Anything more complex than Lanny Henderson's example starts to lose its 
> validity almost as fast as it gets more precise.
>
> The idea is great. It would be really great to have real units of value to 
> compare for rice, corn, bean and wheat cooking as it would real human time 
> intervals like months and seasons and years of meals.
> Making the measurement techno based as opposed to human based creates a 
> near impossible obstacle for anyone other than an elite few and negative 
> dependencies as well.

I would suggest that it would be very helpful to carry Lanny's idea one step 
further, and show a picture of a typical meal with the wood required to 
prepare it, and not just the beans.
>
> As an example:
> For us here at least the Ecostove is the MINIMUM size stove for family 
> adoption. In fact even with it's extreme fire hazard the D-Lux Ecostove 
> with oven and wood rack is the ONLY stove on the Stove list that has the 
> remotest chance for real adoption here and it has that slim chance because 
> it CAN cook for 3 or 30 and approximates affluent stove designs.

Stove design is relatively easy, when operating parameters are narrow and 
specific. The need for versatility generally complicates designs, increases 
costs, and reduces average performance. While it does have a good chimney, 
and as good as it is now, I would suggest that the Ecostove could give even 
better performance, if its internals were sized to meet the average usage 
requirements for the stove. It does not make sense to install a stove that 
will cook for 30 if it is used only once a year for this task... the other 
364 days of the year are probably wasting fuel, with the stove being 
operated in the "turned down mode."

> Of course it would be better to use a TLUD design and of course it would 
> be better to use a smaller design, it just wont ever get adopted until 
> fuel is so short people HAVE to change or a cultural change occurs.

Is there a version ofthe TLUD system that permits continuous operation, or 
is it inherently limited to small batch operation?
>
> The same fuel to meal rule as those in Swaziland or the Bolivian highlands 
> will not work without reams of other calculations of causes and 
> conditions.

Obviously, different meals require different cooking hardware, different 
cooking techniques, and will have different fuel requirements per meal. If 
various foods were placed into basic
categories, such as boiling, simmering, roasting, baking and frying, the 
comparison task would be greatly simplified.

One issue not mentioned so far is the need, or non-need for space heating. 
Obviously, if there is no need for space heating, then the entire wood 
consumption would be "charged off" against cooking. On the other hand, if 
the stove is operating all the time to provide space heat, the incremental 
fuel cost for meal preparation is trivial or insignificant.

> A biomass to food ratio that takes into account the entire ecosystem of 
> the subject would be needed to create a base context for the fuel to food 
> ratio to be really meaningful.

Sure, but we have to start somewhere. If stove improvements don't lead to 
"less trips to the forest", they probably aren't really helpful.

Best wishes,

Kevin