Performance of a 2/spl times/ Cusp concentrator PV module using bifacial solar cells

This paper describes the key performance characteristics of a static concentrator called 2X Cusp Concentrator Module (2XCCM). At this low concentration ratio of 2 the module needs only half of the cells required by a conventional flat-plate module. A prototype, using 14% to 14.5% efficient dendritic web bifacial silicon solar cells was completed in 1990 and subsequently subjected to indoor and outdoor testing. The module produced 39.75 watts at 10.9% efficiency when flash tested indoors. Outdoors the module produced 33.1 Watts at 8.75%. The drop in performance was attributed to soiling of the mirrors and cell fractures. The module generated about 60% of its power output from the cells front surface and 40% from the back surface. In most respects the module performed like a flat-plate module except that its operating temperature was somewhat higher. A cost analysis showed that at an improved module efficiency of 12.8%, using 15%/14% bifacial cells and at a cell cost of $1.33/Watt, the module cost coefficient would be $2/Watt.