In the town of Aipir, Colombia, the temperature can often get as high as 45ºC (113ºF), yet few of the residents have a reliable source of electricity. So, pulling an ice-cold beverage out of the fridge isn't really an option. Coca Cola and the Leo Burnett Colombia advertising agency therefore devised a "Bio Cooler" for the town – it reportedly chills cans of Coke, without using electricity.
The cooler was developed in collaboration with the International Physics Centre in Bogota, and is described solely in a short video released by Leo Burnett. It reportedly works by two methods ...
First, a compartment in the top of the cooler contains plants and soil, while the cans of Coke sit in a chamber below. When the plants are watered and much of that water subsequently evaporates, it has a cooling effect on the chamber.
Second, a mirror in the cooler focuses heat from the sun, which is somehow used to convert an unnamed gas to a liquid state, creating a cooling effect as that liquid is circulated around the Coke chamber. This could conceivably be something like a thermal-powered version of the CryoEnergy System, in which energy is stored by converting ambient-temperature gaseous air into cold liquid air.
Whatever's going on, you can see the Coca Cola Bio Cooler in use, in the video below.