Simple solutions can often have dramatic effects.

That’s the case in many parts of rural Africa, where the lack of access to or high cost of electricity prevents many people from basics most of us take for granted, like refrigerators.

Nigerian Mohammed Bah Abba’s innovative food-cooling system adapted old-world technology into inexpensive, portable refrigerators that are particularly effective in desert climates, where fruits, vegetables, and other perishables can quickly spoil.

Abba, a college lecturer who came from a family of clay-pot makers, saw an opportunity to raise living standards for rural Nigerians. In the late 1990s, he developed a pot-in-pot system that could extend the shelf life of perishables from days to weeks.

His concept costs about two to four dollars and is decidedly