December 13, 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 Dartmouth Humanitarian Engineering (DHE) [formerly 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. DHE students are filing these dispatches from the field during their trip. This is their 18th blog post for Scientific American.
After hearing about Zach [Losordo']s success with the rocket stove in Mwamgongo, we started to talk with our partners from Jane Goodall Institute (JGI) about organizing a more widespread stove distribution program in the Kigoma region of western Tanzania. JGI is a great organization to work with due to their on-the-ground presence and experience providing sustainable solutions to the local communities. The organization is well aware of the problems associated with the traditional three-stone stove and has already embarked on a mission to place fuel-efficient stoves in 25 percent of all the households in the 48 villages in Kigoma district.
After a few talks and stove demonstrations with Grace Gobbo from JGI—a Tanzanian woman who refuses to watch her society stagnate when progress is possible—we were all enthusiastic about integrating the rocket stove technology into their fuel stove program. Gobbo and her JGI colleagues already successfully worked to make fuel-efficient stoves a legal mandate in some villages, and now JGI plans to provide the villagers with the resources necessary to make rocket stoves in their homes.
During our stove demonstrations, we also tested another technology with JGI—a haybox. A while back, Zach had mentioned the potential savings of creating a "haybox" to conserve even more wood for cooking. It is relatively easy to assemble and can be made of locally available materials. An effective haybox can be made from just mudbricks and hay, although wood and other insulation could be used if they are available. Because of its simplicity, the haybox can be custom built for individual families. The key is just to make a box that leaves 7.6 centimeters of tightly packed hay on each side, and 10 centimeters of hay above and below the pot.
The haybox cooking is an age-old method used to conserve labor and fuel. After bringing the food to a boiling point on the stove, the cooking pot can be placed inside the haybox. Operating on the principle of thermodynamics, the hay acts as an insulator and the retained heat slowly cooks the food. No additional energy is required. The haybox works best for "wet cooking" and can be used to cook food such as rice, beans, grains, potatoes and soup. However, while the haybox reduces fuel use, pollution, labor and retains more nutrients that are normally lost through evaporation, it does take three-to-four times longer to cook. You have to start cooking dinner at lunch, and this is not the traditional way to cook.
JGI was pleased with our technologies and decided to propagate both the rocket stove and the haybox in local villages. JGI decided to start with 10 villages, and they sent four individuals into the field to work in pairs. Since there were an average of six sub-villages per village, and two representatives were expected from each sub-village, we expected 120 individuals to learn how to build the stove through the JGI program. The outcome of this program could be tremendously exciting, and JGI kindly invited DHE to observe the initial distribution process for several villages.
We woke up early the next Monday to meet Majaliwa Mkorogo mostly known as "Fish" due to his swimming capabilities and Rehema from JGI to take the local bus. Unfortunately, our translator arrived only to inform us that he could no longer travel to the villages with us. This created serious problems since our Swahili was still at the level of caveman speech, despite our nighttime studying. We called another translator named Stan, and he miraculously arrived at the bus station within 15 minutes in a crisply pressed shirt and his usual big smile.
After many stops and crossing a river on an old-fashioned ferry, we finally arrived at our destination mid-afternoon; the journey had taken us six hours. The first action we took was to visit the chairman of the village and explain the purpose of our stay. The chairman warmly welcomed us into his house and approved of our program. He informed us that someone had brought him the letter JGI already sent that morning, and he had already recruited the villagers we would eventually teach the stove design to. But since it was already late, our workshop was postponed until the following day.
We subsequently spent our first day familiarizing ourselves with the new environment by going to watch a local soccer game match between two villages. Despite bare poles for goals and a battered soccer ball, we were thoroughly impressed by the quality of play. On the way home, a huge crowd of children seemed equally awed by the presence of a white person, as they happily trailed behind Tim, scrambling over each other to hold his hand.
After waking up early from the Muslim call to prayer, we went to the clay site to await the arrival of the people who had been recruited by the chairman. Unlike most villages in the region, telecommunications still has not reached Sunuka and the news of our meeting needed to travel by word of mouth. But before long, a significant portion of people had showed up. The session quickly turned hands on as Fish explained that we wanted to make several stoves, and that each stove required around two buckets (20 liters) of clay and half a bucket of sand. We all started to dig, and the villagers enthusiastically cheered at our inefficient digging skills. The locals made it seem easy, and due to their experience with the local materials, they were quickly proving to be better trained for the job than us.
Most of the afternoon was spent crushing and sifting the clay while Fish taught the villagers how to make each of the four different clay brick dimension sizes. Altogether, two of each of these clay brick sizes made up the stove intake and combustion chamber, and 11 mud-bricks made up the superstructure to provide support for the stove.
Together with JGI, we believe that initial subsidization of the rocket stove technology resources would allow for a greater level of dispersion throughout the communities. DHE donated 120 metal trays for the initial stoves built in the first month, and JGI provided payments of about 66 cents (US) for the initial stoves built along with three sets of molds to construct bricks for each village. The idea is that people with the stoves will see the benefits and those people without stoves will make an investment in the technology. Initial subsidization is a way to get past the tipping point of stove distribution and breach the traditional barriers that can make early propagation efforts difficult. In the village, metal trays can be produced for around 50 cents, while a full set of molds can be made for about $3. Since building molds for each different brick size was expensive, we designed one mold design with shifting pieces to allow all the bricks to be made with only a small amount of wood, reducing the cost of production even further.
The villagers smiled gratefully when Fish handed over the molds to the village government to be shared and used by the people. We all couldn’t wait until the following week to return to the villages and build the stoves.
Images courtesy of Wendy Hado