October 1, 2010 | 1
Editor’s Note: Students from Dartmouth’s Thayer School of Engineering are working in Tanzania to help improve sanitation and energy technologies in local villages. This series chronicles work being done by the student-led group, known as Humanitarian Engineering Leadership Projects (HELP), to design "rocket stoves" in the village of Mwamgongo and top-light updraft design (TLUD) gasification stoves in the village of Kalinzi. The goal is to create a healthier, more energy-efficient cooking apparatus that these villagers will accept and use. HELP students are filing these dispatches from the field during their trip. This is their 12th blog post for Scientific American.
A Tanzanian’s sense of identity is defined by tribal heritage, family and surrounding community. Inquiring about the family of my translator, and good friend, Revocatus Emmanuel, would set you back a few hours and lead you to believe that he has at least ten brothers. He only has five but calls male family members he is close to "brother." I once thought he was making a translation error and said, "You mean he’s your cousin." He looked me dead in the face and repeated, "No, he is my brother," emphasizing the word "brother" and pausing for a moment afterwards as if reflecting on the gravity of the term. The cousin he was referring to had taken Revo out of the small village he was living in with his mother, a poor widowed banana farmer, and sponsored his schooling in town. Revo seized the opportunity, excelled in school and, luckily for us, became our translator. Since going to school and working with us, Revo has returned to his village and helped to rebuild his mother’s home, installing a metal roof in place of the thatch. His cousin truly is a brother to him.
In the absence of a formal insurance market, Tanzanians must rely on their personal connections to overcome life’s challenges. As a result, they spend a significant portion of time fostering their many ties, which often requires a reprioritization of daily activities. It can be frustrating when someone prioritizes lunch with a distant cousin over a scheduled meeting. It’s important to keep in mind the frustration is the result of two cultures not quite seeing eye to eye, and I’m as much at fault for not understanding how rude it would have been to refuse the lunch.
Although cultural differences can present challenges, my experience in the design process with the 12-person panel from the community has been overwhelmingly positive. Over the past few weeks, they have gone above and beyond what I asked of them. As I hoped, they embraced the design process and put in extra hours to bring the new design to life. Overall, we have constructed four prototypes. Each prototype was evaluated based on its cooking performance, efficiency relative to the three-stone stove and visible emissions. The prototyping process involved changing the intake and combustion chamber dimensions until the panel was satisfied with cooking performance according to the specifications mentioned in a previous blog. The efficiency was then tested relative to the traditional three-stone stove. Once the final dimensions were set, the superstructure dimensions were chosen to produce a stable, well-insulated, aesthetically pleasing stove that would withstand long term use.
I have attached some diagrams so that readers can get a better idea of what the stove looks like. The first drawing is of the clay bricks and metal tray. The second drawing is of the mud brick superstructure surrounding the clay bricks. All dimensions are in centimeters.
We now have an efficient stove that the users are satisfied with. We also have the "excitement factor" working in our favor. The group has been talking to the community about their stove. Whenever we walk around the village, we constantly get stopped by people inquiring about the stove, which demonstrates that the community’s interest is growing. Now that we have finalized the design, the group is eager to build the stoves in their own homes. Building the stove in their own homes will demonstrate that they are truly experts at building the stove and will help the group realize the benefits the stove can bring to their families.
When I mentioned to the group that they should build their own stove, my statement was met with resounding chorus of agreement, and a smile from one member of the group, who approached me afterwards and asked me to come to his home. He goes by the nickname Kambe Yote, and he is well known in the village for engineering solutions to the problems people face. He was the main designer and propagator of a more efficient charcoal stove, the designer of an 800-square-foot fish reservoir and a mechanic who frequently makes repairs to broken down boat engines. As he led me to his house, he began explaining that he had already built the design and his family was noticing enormous wood savings.
When I entered his house, I noticed that like most homes in Mwamgongo, the walls were made of mud brick and the roof was made of overlaid sheets of roofing tin. The homes were separated into three rooms, which separated four generations living under the same roof. The backyard contained the kitchen—an adjacent building meant to separate the smoky cooking conditions from the main living area. In the cooking area, Kambe Yote had already built four rocket stoves of varying dimensions using several different materials. His family had switched exclusively to the rocket stove. Apparently Kambe Yote had come to our house the night before the stove seminar where we went over the construction methods with the group, measured the stove and then began building. He made several of his designs using only mud bricks to attain similar dimensions—a design that shows promise where clay sources are not available. It is much simpler to build although it requires some creativity to fix oddly shaped bricks into proper dimensions. It will also probably have less durability as mud bricks do not last as long as clay bricks under high temperature conditions. Regardless, his ingenuity produced a stove that brought his family enormous wood savings. His neighbors and friends have already asked him to build the stoves, and he asked me if he could move forward with the building process. I ecstatically approved of his plan; the more stoves we have in people’s homes, the closer we are to getting past the tipping point where the stove will propagate naturally.
Images courtesy of Zachary Losordo
Get 6 bi-monthly digital issues
+ 1yr of archive access for just $9.99