It is made by putting a clay pot inside a larger clay pot with wet sand in between the pots and a wet cloth on top. As the water evaporates it cools the inside, letting food stored in the inner pot to be kept fresh for some time. It must be placed in a dry, ventilated place for the water to evaporate to the outside.
Evaporative coolers perform poorly or not at all in climates with high humidity.
Although Mohammed Bah Abba of Nigeria patented the device in 1995 and was awarded a Rolex Laureate (Rolex Awards for Enterprise) in 2000 for developing the “pot-in-pot preservation/cooling system”, the device was known at least as early as the Middle Kingdom of Egypt, as seen by the hieroglyphic kbb, "to cool".
Other websites [change]
- Rolex awards page on Mohammed Bah Abba
- The Zeer Pot - a Nigerian invention keeps food fresh without electricity
- Passive Cooling and Zeer Pots
- The Shell Award for Sustainable Development
- Zeer Pot - introduction and downloadable manual on manufacturing zeer pot refrigerators