A pot-in-pot refrigerator or zeer (Arabic: زير‎)

Refrigerate foods without using electricity -this mode of refrigeration goes back at least 5000 years. It uses a porous outer earthenware pot, lined with wet sand, contains an inner pot (which can be glazed to prevent penetration by the liquid) 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 substance. Have any of you tried this. More info - http://en.wikipedia.org/wi