Pot-in-pot refrigerator

In rural northern Nigeria in the 1990s, Mohamed Bah Abba developed the Pot-in-Pot Preservation Cooling System, consisting of a small clay pot placed inside a larger one, and the space between the two filled with moist sand.

Abba, who hails from a family of potmakers, tapped into the large unemployed local workforce and hired skilled pot makers to mass-produce the first batch of 5,000 Pot-in-Pots.

[8] Abba devised an educational campaign tailored to village life and the illiterate population featuring a video-recorded play by local actors to dramatise the benefits of the desert refrigerator.

[7] After the millennium, several international NGOs began to work on the dissemination of this technology in various African countries: Practical Action in Sudan, Humanity First in Gambia and Movement e.V.

This is useful in arid locations near the ocean where drinkable water is a limited commodity, and can be accomplished by using a pot that has waterproof glaze or cement[1] applied to the inner wall where the food is stored.

If any of these key criteria cannot be met at the time when improved vegetable storage is needed, then ECCs or clay pot coolers may not provide sufficient benefits to justify their use.

To determine the effectiveness of evaporative cooling chambers for specific uses it is helpful to consider the following: ECCs or clay pot coolers provide benefits if post-harvest vegetable spoilage is the result of exposure to high temperatures, low humidity, animals, or insects.

See the "Conclusions and Additional Resources" section of the Best Practices Guide[12] for a more complete list of vegetables that can benefit from storage in an evaporative cooling device.

[disputed – discuss] Pot-in-pot refrigeration has had multiple positive impacts on the population that uses them beyond the simple ability to keep food fresh for longer periods of time and decreasing instances of food-related disease.