One exceptional and simple solution, called Zeer, for a long-term storage of food where there is no electricity, is to build your own pot-in-pot fridge, by using basic pots, sand and water.
Zeer, a pot in pot cooler, developed by Mohammed Bah Abba, is a simple invention that works through evaporation, for longer food storage without refrigeration!
A porous outer earthenware pot, lined with wet sand, contains an inner pot within which the food is placed – the evaporation of the outer liquid draws heat from the inner pot. The device can be used to cool any substances such as water, foods or temperature sensitive drugs.
How to build one:
-Obtain two large clay or terracotta pots, the one smaller than the other.
-Fill in any holes at the base of the pots and fill the base of the larger pot with sand.
-Place the small clay pot into the large pot and fill all around the small pot with sand.
-Pour water over the sand and cover it with a wet cloth.
-Keep the pot-in-pot refrigerator in a dry, ventilated space.