Two-stage tilting solar concentrators

In this paper a novel type of two-stage non-focussing concentrator is described which makes economic photovoltaic and thermal solar conversion possible at current prices in many locations. The new concentrators use exceptionally little mirror (1.3–1.8 times full aperture), yet achieve concentrations up to 12 × without diurnal tracking. Optical efficiency is high, and no moving parts are required except for a simple pivot and securing device.