Designing the perfect stove in Central America

A Plancha Ecostove is a thin metal box on legs, full of pumice, with an elbow-shaped ceramic pipe to hold burning wood.  It also has a heavier metal cook-top and a chimney.  It replaces an open fire with a number of advantages:

  •   The person cooking is at much lower risk from fire.
  •   The chimney gets the smoke out of the house, reducing infant blindness.
  •   The stove uses about one-quarter the amount of wood to cook dinner.

The initial design had a hot spot - over the top of the ceramic pipe - that would let you boil water and was hot enough to cook from that spot to the chimney, but a majority of the cook-top was not hot enough for cooking.  The solution was to weld in baffles to break up the air flow.

Welding baffles was quite hard.  The stoves are made in a junkyard in upland Nicaragua.  To weld, the workers swipe power from uninsulated power lines.  They use it to charge a coil salvaged from a car and then discharge the field through alligator clips on the cook-top and baffle to spark-weld the baffle.  This is also not all that safe.

Working for Ethos as part of a larger effort, Dr. Dan Ashlock worked with students and collaborators to use a simulator to run computational fluid dynamics on different baffle designs using the down-time on the computers at a virtual reality research center.  They examined 20,000 baffle designs over a period of six months, automatically generating new baffle designs with an evolutionary algorithm.  The final design achieved the same evenness of heat as an empirical design with twelve baffles - but using only three baffles.  Hundreds of the stoves are now deployed saving lives, eyesight, and money for some of the poorest people in Central America.

A stove with pots and pans

High school students interested in developing the mathematical and statistical skills to tackle a real world problem such as this should consider our Mathematical Science Major, with an Area of Emphasis in Energy and Mass Transfer.

Prospective graduate students interested in working with Dr. Ashlock should visit his website, or read more about Graduate Studies at Guelph.