Mohammed Abba

Mohammed Bah Abba has invented an innovative earthenware cooling system to preserve perishable foods in developing countries with arid climates. As a Nigerian teacher, Mohammed was motivated by his concern for the rural poor and by his interest in indigenous African technology to develop practical, local solutions to rural problems. His simple and inexpensive earthenware "pot-in-pot" cooling device, based on a simple physical principle and used as far back as ancient Egypt, is revolutionizing lives in this semi-desert area of Nigeria.

The art of pottery is deeply rooted in African culture. In northern Nigeria, earthenware pots have been used since ancient times as cooking and water storage vessels, wardrobes, banks, and coffins. Today, these clay pots are almost extinct, replaced by aluminum containers and more modern methods of storing clothes, saving money, and burying the dead. The pot-in-pot refrigeration device consists of two earthenware pots of different diameters, one placed inside the other. The space between the two pots is filled with wet sand that is kept constantly moist, thereby keeping both pots damp. Fruit, vegetables, meat, and other items such as soft drinks are put in the smaller inner pot, which is covered with a damp cloth. The phenomenon that occurs is based on a simple principle of physics: the water contained in the sand between the two pots evaporates towards the outer surface of the larger pot where the drier outside air is circulating. By virtue of the laws of thermodynamics, the evaporation process automatically causes a drop in temperature of several degrees, cooling the inner container, destroying harmful microorganisms and preserving the perishable foods inside. Mohammed's invention has already had significant impact in more than a dozen Nigerian villages. By preserving food, the pot-in-pot increases family income, reduces disease, and even frees young girls from having to hawk food every day so that they can attend school. Best of all, the invention is simple and affordable, made from local materials, and can thus be quickly introduced to villages facing similar problems in Nigeria and across Africa.