Research activities were aimed at finding innovative solutions to enhance the efficiency of Concentrated Photovoltaic (CPV) systems and to identify suitable solutions for both utility-scale applications and integration into architectural and residential buildings. Two distinct approaches were adopted.

The first approach involves the development of a new hybrid CPV/PV module concept with an economical, precise, and reliable solar tracking system integrated within the module itself. In this CPV/PV module, the optical concentration system is positioned on a fixed plane, while the CPV cells, each with an area of 9 mm², are mounted on a movable plane that can translate parallel to the optical plane. The key feature of RSE’s tracker is the use of shape memory actuators, which, compared to conventional electric motors, offer significantly lower costs and weights, as well as greater reliability, though they present control challenges due to their nonlinear behavior. In Activity Line 1.03 of this project, an initial version of the control system was developed, achieving promising precision results but not yet suitable for aligning the CPV cells. In this activity, the control system was improved through the development of a new high-resolution solar pointing sensor, modifications to the mechanical system, and optimization of the control algorithm. Testing of the new prototype demonstrated that a precision of ±0.1 mm can be achieved over a displacement range of ±30 mm, allowing the use of optical systems with concentration factors up to 400 suns and focal lengths of a few centimeters. The development of the optical concentration system for the hybrid CPV/PV module in this activity has undergone several revisions to match the performance achieved with the tracking system. The final concentrator consists of a plano-convex lens with a spherical profile and an angular acceptance of 10°.

The second approach focuses on reducing the thickness of the high-concentration CPV module for use in medium to large-scale installations. In Activity Line 1.03 of this project, several new optical configurations were designed, studied, and simulated to reduce the solar concentrator’s thickness to 5-6 cm while maintaining a high concentration level (greater than 400 suns). In this activity, a first version of the reduced-thickness concentrator (micro-concentrator) was produced and its actual performance was measured. The prototype concentrator has a vertical dimension of approximately 54 mm and an exit aperture of 1×1 mm. The characterization of the prototype showed a concentration factor of 412 suns and a light transmission efficiency of 78%. The achieved light transmission and optical efficiency are consistent with the values predicted during the simulation for the material used.