Light-trapping in solar modules using extra-white textured glass

The objective of this work is the development of a front cover glass for all types of PV modules allowing a significant reduction of optical losses at the glass-air and the polymer-cell interface. The annual relative gain in transmission between a plane surface and a inverse pyramidal-textured (half-angle=45/spl deg/) surface has been calculated to be 8.1% for direct radiation and 6.1% for diffuse radiation for a standard year in Cologne (Germany). This glass has been manufactured on an industrial cast glass furnace during an extra-white campaign. It allows an annual efficiency improvement of 3.1% (2.9% at normal incidence and 9.4% at 70/spl deg/) compared to flat glass with the same composition and measured with polycrystalline Si solar cells. After 9 months outdoor testing (on a dusty test site, 60/spl deg/ tilted to a horizontal surface), a significant advantage of the pyramidal glass (compared to flat glass) is still present.