Internal lighting by solar collectors and optical fibres

Sunlight concentration on small surfaces is widely studied [1-3], experimented and mostly applied to photovoltaic power generation [4-6]. More rarely these solar collectors are coupled to optical fibres [7-9], with the advantage of always having a circular absorber shape. On the contrary the photovoltaic (PV) cell is typically squared and therefore it requires a secondary optical system to reshape the image and to improve the light distribution uniformity. The introduction of optical concentrators, especially high concentration systems, has two positive effects: it reduces the area of expensive solar cells and it increases their efficiency. The main reasons for this development are enhanced efficiency of CPV (concentrating photovoltaic) systems due to new solar cells, improved size of PV installations and increasing interest in alternative technologies, both due to government incentives and to the poor Silicon availability. In general it can be assumed that an improvement in the volume of the collection system reduces the costs, given that the system provides a higher production of energy.