V-TROUGH CONCENTRATOR ON A PHOTOVOLTAIC FULL TRACKING SYSTEM IN A HOTDESERT CLIMATE

A V-trough concentrator with a two-axis tracker system to increase the performance of photovoltaics was designed by the authors and installe d on the roof-top of the building of the National Research Institute o f Astronomy and Geophysics at Helwan in South Cairo. The V-trough conc entrator system comprises two flat mirrors with dimensions 50 cm x 18 cm. They are fixed with the reflecting surfaces facing each other with a separation of about 11 cm, on a wooden table of 50 cm axis length. A sample of polycrystalline and amorphous silicon solar cells were fu; ed into the system, and similar solar cells of each type were fixed se parate to the system, to estimate the electrical gain. The measurement s were performed daily at different air masses for one complete year. The temperature of the solar cells in and out of the system were measu red for comparison. Also, measurements for beam and global solar radia tion and other meteorological conditions were recorded. The optical lo sses of the system were analyzed and details of collectable energy cal culations are presented. The energy gain from the isolated contributio n of the V-trough concentrators is also evaluated.