The PV-FIBRE concentrator:: A system for indoor operation of 1000X MJ solar cells

This paper describes the overall design and experimental results obtained with the PV-FIBRE concentrator system (CPV). This system uses a parabolic dish to collect and concentrate the sunlight which is then further guided by a transparent rod and finally by individual short fibres. Eventually, the individual fibres are connected to single cells which are located indoors. Dual-junction III-V-based solar cells with an efficiency of 30% and operating at 1000x are applied in the PV-FIBRE system. This new system approach allows a suitable optical and electrical interconnection in order to reduce the losses and the indoor operation of the cell receiver. All elements of the CPV system (collector, tracker, transmission rod, cells, fibre bundles, and cooling circuit) have been manufactured according to main design requirements and have been evaluated separately. Finally, the PV-FIBRE CPV system has been installed in Madrid and tested under real operation conditions. The system has demonstrated an optical efficiency of 62% is feasible, providing homogeneous illumination to the cells. Therefore, this concept can lead to overall efficiencies exceeding 20% when combined with MJ solar cells. In this paper we report on the main achievements, identified problems as well as lessons learned and future research lines to improve the system performance. Copyright (C) 2007 John Wiley & Sons, Ltd.