This Small Business Innovation Research (SBIR) Phase I project investigates novel optical element (OE) for Photovoltaic (PV) systems that uses refractive index modulation to steer sunlight. It addresses the fundamental challenge of tracking the motion of the sun while keeping the concentrated light on the target. For decades this has been accomplished electro-mechanically using motors and feedback circuitry to physically move the optics and/or the target so that the device is always aligned with the sun. This project develops a simple, motion-free tracking system that eliminates all the negative aspects of current mechanical trackers. It is suitable for deployment on any PV system by adapting the optical characteristics. The project goals are to optimize design elements of the OE including materials, configuration and manufacturing technique, and building prototypes for testing in both lab and field sites. Phase I will establish a prototype of a motion-free tracking collector and concentrator that will address three interconnected design issues. These are 1) maximizing throughput of the device by eliminating unwanted reflections from various interfaces, 2) maximizing the range of solar incidence angles, and 3) lowering the cost of the finished device for commercialization.
The broader impact/commercial potential of this project will be to enable widespread adoption of localized solar power generation. This technology solves the inherent complexity of simultaneously realizing mechanical stability under wind and seismic loading, electro-mechanical tracking accuracy, and eliminates high costs associated with mechanical trackers. Phase I of this program will establish technical benchmarks to maximize the steering range and light concentration ratio for a novel motion-free tracking system. New conductive coatings are index-matched to minimize internal reflections that cause loss of light throughput, while lens geometries and other components will be engineered to maximize efficiency of the system. Because the device is low-profile and lightweight, it can be easily installed on existing rooftops without requiring substantial structural reinforcement, making commercial acceptance likely. This motion-free tracking technology has these commercial advantages over existing solar PV systems: simple, inexpensive installation, low profile esthetics, and more efficient solar power generation for commercial and residential installations. In summary, it will generate more electricity from a smaller footprint for lower overall cost.
