Safer, cheaper coal bricks
With Guy Fawkes freshly past, fire and its power are still on many of our
minds. Fire fascinates. Fire cooks. Fire warms. In Africa, fire is the energy
source most often used to cook. As renewable sources of fuel, such as wood
become scarce it is important for any society to make the transition to
mass-produced fuels such as coal or paraffin, and then later shift to
electricity or gas.
In Africa many people have grown up in communities where fire has cooked the
meals that have fuelled the careers of academics who have left that world behind. Every now and then however one of these academic careers
spawns an innovation or invention that feeds back to create a better life for
all.
Coal dust is a widely available waste product of the large and well-developed
coal industry in South Africa. In 1999 Dominic Adams, Matthew Lowe and Andrew Russell,
students at the University of Cape Town in South Africa, began work on
developing a system to turn coal dust into an affordable heating and cooking
alternative.
In order to convert soft powdery coal dust into a solid burnable unit, a
special binding agent had to be developed. For health and environmental
considerations it is important that this binding agent is natural. It
consequently does not release many dangerous toxins into the atmosphere.
The briquette design employs an innovative "Swiss cheese
like" configuration of holes running through it to increase surface area
available for burning and hence increase heat output.
In order to harness the heat released by the burning coal dust briquettes it
was necessary to develop a special oven designed to maximise the energy
available for use at a minimum cost to the user. The stove stands about half a
meter high and weighs 80 kg. It is made from solid concrete that is mixed at the
right percentages to make it heat resistant. It has a chute down the middle
which the briquette fits into and has a vent at the bottom of the chute which
can be opened and closed to regulate combustion.
There are ridges on the brim of
the stove which allows the pot or what ever is on the stove to sit proud in
order to not constrict the circulation of oxygen. The stove never becomes
incredibly hot and therefore will not cause burns if brushed up against. Once
the vent is in place a vat of water may be placed on the top of the stove which
will be slow-boiled by the smoldering briquette. An efficient way of purifying
the water and reducing the amount of water bourn diseases contracted by the
family.
Another benefit to rural communities is the decreased reliance on paraffin
that this stove will provide. More than 3500 children die a year in South Africa
alone from accidental ingestion of paraffin. A coal brick is far less likely to
be eaten by a child and if it is, it is unlikely to enter the lungs and cause
death as paraffin does.
Innovations such as these are important steps towards the South African and
African dreams of creating a better life for all. They were one of the top ten
finalists in the recent national Catalyst Innovation Competition.
The next step in the road for the team is to find the capital to build about
50 000 units for placement around South Africa. They have already been
approached by venture capitalists.
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