SPECTRUM project

The optical design of the solar collector is a fundamental aspect of the study for the realization of the system. The final aim of the optical design is to collect the maximum power, taking into account the diameter of the fiber and the NA, while a classic design foresees to obtain the best image. Several projects of optics have been done and some of those have been realized. The configurations studied as solar collectors are six: the table below summarizes them by presenting their salient characteristics. The optical design of the CCM (Monobloc Catadioptric Concentrator) was developed with the aim of optimizing not only the optical characteristics of the collector, but also its compactness.

The efficiency obtained from the collector coupled with the 0.6 mm diameter fiber has been theoretically estimated and experimentally measured. This comparative study shows that the CCM designed for our solar device has a reduced thickness, is easy to mount and align, and achieves a good level of concentrated power. Instead the Mangin type configuration represents the best compromise between efficiency and cost. For this type of collectors, as for parabolic ones, the mechanical alignment between the concentrator and the optical fiber is a critical aspect because the secondary mirror is separate from the primary one and is made on the protective glass of the tile. The difficulty of alignment increases when you have to align a tile, which contains four concentrators. To choose the manifold to be made in the prototype of the system we considered both the advantages and disadvantages of each individual concentrator, summarized in the table below.

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