The novel concept of building integrated CPC reflectors

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A different approach for low concentration photovoltaics has been investigated, combining effectively stationary symmetric or asymmetric CPC reflectors [25] with PV absorber strips and thermal absorbers. A first system is the stationary CPC reflectors with flat bifacial absorber, where two PV strips can track the converged solar radiation on each absorber side and absorb the concentrated solar radiation to convert it to electricity (Fig. 6a). The non-absorbed beam solar radiation and the diffuse solar radiation are absorbed by the flat bifacial thermal absorber and can be taken away to a thermal storage (or directly to the use) by the circulation of a heat removal fluid. The PV strips operate in a similar way as in the Fresnel lens device. A second CPC type concentrating photovoltaics is the asymmetric CPC reflector (Fig. 6, b and c) where the thermal part is a usual type of thermal collector and the PV strip is moving infront of the thermal absorber tracking the converged radiation. In this system the parabola axis can be directed to higher altitude of sun (summer, Fig. 6b). An alternative design can be also realised (Fig. 6c) where the parabola axis is directed to the lower sun altitude (winter). In the last two devices, the non-absorbed converged solar radiation and the diffuse solar radiation are absorbed by the well thermally insulated flat absorber and result to the heating of the circulating liquid.