In order to maximize the conversion efficiency of the solar cells and of the complete concentrating system, some CPV designs act onto the spectral properties of the light together with the geometrical ones. Each photovoltaic materials has the best photovoltaic performances for wavelengths with energy slightly higher than the semiconductor bandgap. A splitting of the […]

The design of solar concentrators has different drivers respect to imaging optical elements. Indeed, the design goal here is to maximize the flux density, i. e. the irradiance, at the receiver. Different methods can be implemented to achieve this result (Winston et al., 2005); one of the most commons is the edge ray method. This […]

The optics for the Sun concentrators have been mostly developed during the last 30 years; the non-imaging optics, a branch of geometrical optics, has given a great contribution to the evolution of the shapes for solar light concentrators. For this application there isn’t the concern to reconstruct images avoiding distortions, but the aim is to […]

Andrea Antonini CPower Srl Italy 1. Introduction The main obstacles for the photovoltaic energy to be competitive with standard energy sources are 3: the low efficiency, intended as low density of energy production for occupied area, the high cost of the constituting materials and the variability of the production which is correlated to the meteorological […]

A demonstrator of our solar collection system was installed in a prestigious museum in Florence to provide illumination inside several large showcases. The width of the showcases can be 5m or 2m, while the height is 3m. The photos of Fig. 21 present two 5m X 3m showcases: the pictures show the showcases before (left) […]

The museum demonstrator employed a combination of solar light and other sources, represented by white LED with high emission levels at low supplying power (DGA product number 700001.31 "1W fixed LED gem", ref. www. dga. it). Museum object illumination has specific requirements on illuminance levels, light colour and light distribution uniformity. The first task was […]

The optical coupling between solar lens and fibre bundle was one of the major causes of energy losses in the whole optical system of the museum demonstrator. The focused light should be received by the fibre with the maximum optical coupling obtained in the best alignment condition. As regards the core diameter, we finally chose […]

The solar lens with anti-reflection coating was tested in various atmospheric conditions to estimate the endurance of the treatment. An obvious negative effect was the deposit of raindrops or dust on the upper lens surface. However, the most disturbing effect appeared to be water condensation on the lower lens surface, occurring in sunny weather or […]