This report by the MIT D-Lab Evaporative Cooling for Vegetable Preservation group and collaborators covers their work in Mali from 2016 to 2021 and includes:
- Evaluating suitability and user needs
- Lab testing and shelf life measurements
- Conclusions and next steps
Food, water, and electricity are what many people consider basic needs, but these are still luxuries to many people around the world. Imagine spending up to an hour walking to purchase vegetables every day because you don’t have a way to store vegetables that keeps them fresh and pest-free. This is exactly what happens to many people in communities where access to electricity or affordable vegetable preservation methods are limited. In Sub-Saharan Africa alone, 30% to 50% of fruits and vegetables harvested are lost before reaching the consumer.
One way this problem can be addressed is through the promotion and use of clay pot coolers for storing and preserving fruits and vegetables. They are an affordable and accessible solution that use evaporation for cooling and do not require electricity to run. The most common clay pot coolers, or “Zeer pots,” are made of a double-wall earthenware container with the space between the two clay walls filled with wet sand. When the water from the outer surface evaporates, the inside of the container where the vegetables are stored - is cooled.
While clay pot coolers and other evaporative cooling technologies have been shown to effectively increase the shelf life of many fruits and vegetables, these technologies have not gained widespread adoption. This is because of the lack of product evaluations based on real-world scenarios and user behavior to inform the design of dissemination programs. MIT D-Lab’s Evaporative Cooling research group aims to bridge this gap and increase the dissemination of clay pot coolers in appropriate contexts. The D-Lab clay pot cooler project started in 2016 and has consisted of multiple phases, each focusing on a different technical and social aspect of this technology.
Recent results not included in this document include:
In May of 2021, 11 training workshops were conducted, reaching 289 participants. Of the 265 people who were reached for an interview 10 months after attending a half-day training workshop conducted in the Mopti region of Mali, 73% had constructed or purchased clay pot coolers for personal use. Among these clay pot cooler users, 98% reported less food waste, 95% reported spending less time traveling to buy fruits and vegetables, and 88% reported eating more fruits and vegetables since using clay pot coolers. The training of 54 clay pot sellers resulted in the sale of nearly 2,000 clay pot coolers in the 10 months after the half-day training workshops, and the training participants reported sharing information about clay pot coolers to a total of 2,600 other people.
Eric Verploegen, MIT D-Lab Research Engineer, Evaporative Cooling Lead