Design of a color neutral non‐patterned photovoltaic window based on luminescent solar concentrator

The necessity to fulfil buildings energy demand with different energy sources lead to an increasing integration between building components and renewable energy sources. The development of new BIPV technologies requiring less silicon solar cells for active area is particularly interesting especially from a circular economy perspective. This work describes the design of five neutral color photovoltaic windows based on large area (0.61 m2) luminescent solar concentrators, which were developed by the University of Ferrara and Eni S.p.A and were installed at the Eni “Renewable, New Energies and Material Science Research Centre” in Novara (Italy). The prototypes show a visible transmittance of 38.5% which represents an improvement with respect to commercial semi-transparent photovoltaic technologies, moreover the evaluation of the window colorimetric properties highlights a color rendering index equal to 93.0, thus ensuring an excellent illumination quality of the building indoor. The panel electrical performance was measured indoor, at the end of the assembly process, and on-site, showing a power production ranging from 1.2 W to 2.8 W and an efficiency between 0.23% and 0.48% depending on the illumination condition and the background reflectivity. Although the generated power is limited, it is already sufficient to power stand-alone small appliances and smart systems.