The Linear Mirror
The Linear Mirror is a very simple way of concentrating solar energy.
It was developed by the accademic spin off company Isomorph srl of Hans Grassmann.
It can heat either water or air, and it is efficient also at northern latitudes, providing heat also in winter.
It is also suited for industry and is cost competitive with fossil fuels. According to the byzantine grammarian Tzetzes, Archimedes has used this kind of mirror for defending his home town Syracuse 2.300 years ago. The Linear Mirror corresponds to Tzetzes description, traditional mirror systems do not correspond.