Picked this up while trawling the No Tech archives. http://www.mitticool.in/product_detail.php?product_id=4
"A fridge for the common man that does not require electricity and keeps food fresh too. With this basic parameter in mind Mansukhbhai came up with Mitticool, a fridge made of clay.
It works on the principle of evaporation. Water from the upper chambers drips down the side, and gets evaporated taking away heat from the inside , leaving the chambers cool.
The top upper chamber is used to store water. A small lid made from clay is provided on top. A small faucet tap is also provided at the front lower end of chamber to tap out the water for drinking use.
In the lower chamber, two shelves are provided to store the food material. The first shelf can be used for storing vegetables, fruits etc. and the second shelf can be used for storing milk etc. Cool and affordable, this clay refrigerator is a very good option to keep food, vegetables and even milk naturally fresh for days."
It is a very neat updating of the terracotta wine coolers that a lot of people have.