Pot in Pot cooling System

Pot-in-Pot Cooling System.
Invented by Mohammed Abba, Nigeria

A small earthenware pot is placed inside a larger one, and the space between the two is filled with moist sand. The inner pot is filled with fruit, vegetables or soft drinks; a wet cloth covers the whole thing. As water in the sand evaporates through the surface of the outer pot, it carries heat, drawing it away from the inner core. Eggplants stay fresh for 27 days, instead of the usual three. Tomatoes and peppers last for up to three weeks.

A simple technology, but with profound social implications. It has freed thousands of families from the tyranny of selling fresh produce on the same day, or risk it getting spoilt. At 40 cents a set, innovations don't come cheaper than this !