The people over at Green Power Science have whipped up this great video showing how to use Fresnel lenses to heat water. As they mention at the end of the video, your lens pointing at a black object will generate as much heat as a black object the same size as the lens, but I imagine this could make for some very interesting solar heating options.
Has anyone experimented with Fresnel lenses or any solar heating projects that could benefit from the ability to concentrate light like this? I’d be interested to hear! Feel free to post in the comments or on the forum.