There are still many parts of the world without ready access to electricity. This makes it hard to preserve medicines or to store foods that could quickly go bad.

But 21-year-old Emily Cummins -- previously named as one of the Future 100 Young Entrepreneurs of the Year and the Ultimate Save-The-Planet-Pioneer in the Cosmopolitan Ultimate Women contest -- has come up with a solution: a solar-powered fridge that can be made from fairly common materials.

Designed as a method of transporting medicines, Cummins' fridge is small and cylindrical ("there are fewer areas where bacteria can build up"), making it easily carried. It uses the power of the sun to evaporate water inside the chamber, which in the process removes heat. This allows the interior of the device to stay as low as 43 degrees for days at a time.

Not only does this fridge sustain what's inside it, it can also be made sustainably, from just about any type of materials that are on hand.

Cummins recently spent five months in Africa demonstrating and testing her product, an experience that led to people in Namibia dubbing her "The Fridge Lady."

While this idea wouldn't take the place of the GE in your kitchen, it does achieve a great deal, and could help to change the lives of hundreds if not thousands of people around the world.

See also the DIY Fridge for developing countries.