Intermediate Concentration Systems for Terrestrial Photovoltaic Panels

Abstract

Experiments using a patented process of intermediate concentration (2 to 10x-sun) on off-the-shelf terrestrial photovoltaic panels are described. This intermediate concentration is obtained with segmented parabola collectors. The collectors are cut out of expanded polystyrene, using a hot wire and surfaced with inexpensive back surfaced mirrors. Collector widths can be varied, up to 4.88 m (16 ft) or more, to give the desired concentration on a given photovoltaic module. The use of wide parabolas is made possible through the use of an azimuth tracking platform. The platform can be floated on a shallow pool of water, or placed on wheels. The parabolas are either mounted flat on the rotating platform and tracked by keeping the axis pointed at the sun, or cut into 0.61 or 1.22 m (2 or 4 ft) lengths and tracked in an altitude mode on the azimuth tracking platform. Active cooling is used to increase the efficiency of the cells and provide a source of thermal energy to use for domestic hot water and space heating. The hybrid systems made possible by the low-cost intermediate concentrators, open up new immediate marketing possibilities that need to be explored.