I had heard of this fridge but not seen the description before:
One of the biggest advantages of Cummins’ design is its relative simplicity. It can be easily made using recycled materials, such as cardboard and metal.
Ms. Cummins' solar powered refrigerator works like this:
The fridge’s inner chamber, which stores items like milk, cheese and other perishables, is surrounded by a layer of organic material, sand, soil or composted waste.
This layer is then sealed in between the solar fridge’s outer chamber and soaked in water. The device is placed in the sun and as the water evaporates, heat is drawn away from the inner chamber, dramatically cooling items inside.
Found on the energy matters web site.
