Winner of the 2007 red dot design concept award: The portable BCK Solar Cooker makes solar cooking easier! The BCK resembles a Thermos but includes a solar shield that reflects the sun’s rays into its center, which can build heat up to 90 degrees Celsius. It requires only water and sunlight.
Foods cook at a constant temperature and about as fast as on a conventional stove. Of course, you can also sterilize water in the cooker.
When set up, the cooker is conical in shape. The conical reflection shield reflects the sun into the centre of the cone, where a black cylindrical food container collects the heat. After about 45 minutes, the temperature of the food is around 90 degrees Celsius. The size of the cooker is very small: 250mm in height and 130mm in diameter. The BCK Solar Cooker can be easily transported in the backpack. It would be particularly useful during activities such as mountain expeditions or bike tours.
The disadvantage is that the conical shield must be focused often to follow the sun.
The BCK Solar Cooker is a prototype, but the designers are willing to take it into production, so if interested you can contact them through their website.
[Text borrowed from http://yum.tv/?p=1716.]