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A.D
1. Thanks for sending this interesting story on.
Not a permanent problem - hopefully, just a new point to add to your educational
program. Old ideas die hard.
2. What are the dimensions and weight of your briquettes?
(Number making up 100 g?)
3. You
probably said this earlier - but what is your recommended binder
formula?
4. You have described your new stove previously, but I think it
needs a repeat - as 70% is just fantastic. Congratulations!!
5. I do not recall anyone claiming this high an efficiency
value. I believe you have incorporated what we might call a
"convection-enhancing-sleeve" which is probably key to this high
value What is the gap width and height you have chosen in the model
now in production? What is the method of measurement?
6. Do you have any means of controlling air flow and power level of
this stove design?
7. It is becoming more clear all the time that the Ashden award
people made a wise choice.
Ron
Dear Tom and Paul,
I spent the last four days at Phaltan, looking at the
charring kilns installed by ARTI at various sites. The operators in most
cases are unemployed rural youth. After demonstrating the process to
them on our own kiln they were provided with a kiln of their own,
and they were asked to char sugarcane leaves in their own villages. In
all the cases, they had unofficial advisers, who had already made charcoal
using the traditional kilns. In the traditional process, the biomass to
be charred is loaded into a kiln and ignited. One has to regulate the
air supply very judiciously in order to have the right temperature to cause
the biomass to char, but at the same time not provide so much oxygen that the
biomass burns down completely to produce ash. In our oven and retort
model, the biomass to be charred is enclosed in barrels and it never comes in
contact with oxygen. We therefore keep all the airholes fully open, so
that the biomass surrounding the barrels burns intensely to pyrolyse the
biomass inside the barrels. Our
entrepreneurs unfortunately followed the advice of the traditional
charcoal burners in their villages and contrary to our advice, closed all the
air vents, resulting in a very slow burn of the biomass surrounding the
barrels. This not only increased the batch time but also in producing biomass
which was just roasted and not charred.
Most of them were totally discouraged, firstly because of
low output and also because of its poor quality. The correct process had
to be demonstrated again at each site. We thought that we had developed a
fooproof process, but it turned out that we were the fools believing that the
villagers would easily be able to produce char using our technology. Our
technology, if correctly employed, would yield about 50 kg char per 8 hour
shift.
The char is sold in the form of briquettes. We started
out with the extrusion process to convert the char into cylindrical
briquettes. But in the field, there are problems with electric supply (either
too low voltage or no electricity at all). So, during my stay at Phaltan
we took the decision to provide the entrepreneurs with molds to produce the so
called honeycomb briquettes manually. These briquettes look like mud pies,
they weigh 100 grams each and each briquette has a set of 13 holes. So when it
is ignited, the pot is hit by 13 flames. I myself produced these
briquettes at the rate of one per minute. Thus by using our mold,
a person can produce 50 kg dry briquettes per day. If the
entire family works on this process, they can earn Rs. 250 per day (US$
5), which is more than what an average industrial worker earns in a
city.
We have developed a stove-and-cooker system for using the
char briquettes most rationally. Through using a very scientific
design, we achieve 70% efficiency with our stove-and-cooker. Just 100 grams of
briquettes can cook rice, beans and vegetables for a family of family.
We tested various prototypes and have now given orders to a stainless
steel pots manufacturer to mass produce this cooker. We expect to
get the first batch of cookers in about a fortnight and then see how
we can market them. We shall sell them very cheaply (at practically no
profit), because the user of a cooker is the potential buyer of the
briquettes.
Yours
Dr.A.D.Karve, President,
Appropriate Rural Technology Institute
Pune, India.
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