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.