In 2001, Nigerian Mohammed Bah Abba won the 2001 Rolex Awards for Enterprise with his invention of a simple cooling system to preserve food in rural areas with no electricity. His solution was a Pot-in-Pot refrigerator, which relies on the concept of evaporative cooling. The system
Evaporation causes a cooling effect in the inner pot. Eggplants are reported to stay fresh for 27 days, nine times their usual expiration date. Tomatoes and peppers can last for up to 21 days
How to make it.
Tools and Materials
• Two clay pots, one larger than the other
• Cloth to cover the pots
• Clay, cork or other material to plug holes in the pots if they have them