Tackling a Burning Issue
Mechanical engineering senior Chris Hewitt, cuts refractory bricks for a wood burning stove combustion chamber during an internship in La Paz, Bolivia.

Cooking stoves are far from the first thing that comes to mind when contemplating the modern design challenges facing mechanical engineering students. Unless, that is, the students are in assistant mechanical engineering professor Margaret Pinnell's engineering materials laboratory at the University of Dayton (UD).

It is not unusual for students in her class to be asked to examine the durability and insulating properties of refractory bricks used in wood-burning, cooking stoves produced with indigenous materials from several Central and South American countries.
 
The study of bricks in Pinnell's class is just one part of a much larger program started in the spring semester of 2001 by a group of five UD capstone design students who decided that they wanted to undertake a project that included working in a developing country. The result of their efforts is proof of the difference a few individuals can make when they sent their minds to it. By the ended of the semester they had established a new organization, known as ETHOS-for Engineers in Technical, Humanitarian Opportunities of Service-Learning-which has since burgeoned into a national organization affiliated with several other universities and related groups.

Ground Fires

During the formation of ETHOS, which served as the students' capstone design project, they teamed up with Aprovecho, an Oregon-based organization dedicated to alternative technologies that are ecologically sustainable and culturally responsive. Since the mid-1970s, Aprovehco has been creating cooking stoves for people in developing countries. A primary goal is to eliminate ground fires, which create detrimental indoor environments, cause clothing to catch fire, and are inefficient. This focus on wood-burning stoves, coupled with the dictum that the stoves be produced locally, is what led Pinnell's students to study bricks.

"The poorest of the poor in developing countries are brickmakers," explains Pinnell. "We want to feed the local economy and make sure that they are the ones producing the bricks for these stoves. We want to give them guidance as to what makes a good brick and what doesn't, using the materials they have available." And, she adds, "Aprovecho has been very good about giving us bricks and brick recipes, and at identifying problems that we take back to the classroom." Aprovecho has also brought Iowa State, Seattle University, and Colorado State University into the ETHOS fold.

An appropriate technology stove containing a combustion chamber (left) built by University of Dayton senior Chris Hewitt.

Engineering Challenge

While at first glance, it would seem that a wood-burning stove would not be much of an engineering challenge, Pinnell begs to differ. "You would be amazed," she says of the engineering complexity involved in such a seemingly simple device. "The biggest challenge with appropriate technology is that it is very local. You may come up with a solution in one region but then you go to another region, and their styles of cooking are completely different so you have to develop a completely different solution."

ETHOS related work has also extended to UD's heat transfer lab where ME students work on models of wood burning rocket stoves, which feature a ceramic combustion chamber and chimney surrounded by low mass insulation. Students in the engineering experimentation lab also work on wood stove projects.

Though the students who founded ETHOS were not able to go abroad during their capstone semester, they did a 2002 summer internship designing, building, and testing environmentally friendly wood burning stoves in Guatemala through their affiliation with Aprovecho. The following year 11 Dayton students volunteered for similar work in, Bolivia, Honduras, Nicaragua, and Peru. This summer 14 students will participate in the internship program, and for the first time they will receive up to three credit hours for their efforts. To receive credit they must prepare for their experience by taking a course in appropriate technology, and a four-week crash-course in Spanish. They are also required to write papers about their experiences and must remain in the host country for at least six weeks.

Untrod Territory

One of the students who was inspired to volunteer for overseas duty by his experience in Pinnell's class was ME senior Chris Hewitt, who spent two months last summer in La Paz, Bolivia, where he worked with local people from Proleña, another organization that has a partnership with ETHOS.

Hewitt opted for Bolivia because it offered untrod territory as far as ETHOS internships were concerned. He and fellow student Bill Strosnider were the first ETHOS interns to go to La Paz, where they joined three Proleña people who had recently begun work on stove technology. The students' first assignment was to run efficiency tests by determining how much water could be boiled using specific amounts of wood. "I also developed my own stove design, had it fabricated and started testing it," said Hewitt.

To determine if the local people would accept their stove designs, Hewitt and Strosnider "drove to a remote village an hour out of La Paz, set up the stoves and cooked some chicken on market day," said Hewitt. "The purpose was to see what the people's reaction would be. We drew a big crowd. I asked people what they thought of the stoves, and how they would like to see them changed. For example, do you need a bigger frying surface?" Answers to such questions led to further modifications and testing, and though the two UD students stayed in Bolivia for two months, "the work was not nearly done when we left," said Hewitt.

Total Immersion

In addition to gaining engineering experience, ETHOS internship participants are totally immersed in the culture of the countries they visit, which includes living with local families.

"You do engineering from nine to five and when you go home you have this whole other experience until the next morning, and that is like a fun job in itself," said Hewitt, who stayed with a woman and her son in a modern apartment building in a suburb of La Paz.

"They took me in as their family. I'd come home, eat dinner and talk to them about life in Bolivia," said Hewitt, who was even invited to attend a daughter's wedding. "That was really cool. You can take years of Spanish, but there is nothing like learning it at wedding where everyone is dancing, and drinking," he said.

People from several Central and South American countries benefit from smokeless stoves that ETHOS engineering students helped develop.

That Hewitt learned the language well is evidenced by the fact that "The last week I was there I went to Peru myself for a week and I had to get by on my own Spanish. By then I was having conversations with people," he said.

In addition to learning to converse in Spanish, Hewitt found that the overall experience greatly expanded his horizons. "Doing engineering, and finding out about this new culture halfway around the world enhances you in ways a regular co-op will not," he says. "It gives you a lot of perspective on what's important…You come back to America and appreciate what you have a lot more."