I like this, Alper. In addition to being used for cooking we had a team in our Cleantech to Market program at UC Berkeley looking at using concentrating solar technology (with a similar parabolic reflector focusing on a tube) to both sterilize and move water in developing nations (which are currently using expensive and polluting diesel generators). It's great to see solar energy being used for more than the direct creation of electricity.
Love this idea, Andre. I have a student team in our Cleantech to Market program at UC Berkeley working on a modular roofing project, ReMaterials (http://re-materials.com/product/), which could very well benefit from a Liter of Light. I have shared your OpenIDEO Challenge site with them.