Solar energy: Cheaper solar concentrator with fewer photovoltaic cells

While engineers have already developed high-efficiency solar concentrators that incorporate optics to focus the sun hundreds of times and can deliver twice the power of rigid solar panels, the new design offers potential new benefits. Existing solar concentrator systems typically use arrays of individual lenses that focus directly onto independent photovoltaic cells which all need to be aligned and electrically connected. In contrast, the new solar concentrator collects sunlight with thousands of small lenses imprinted on a common sheet. All these lenses couple into a flat "waveguide" which funnels light to a single photovoltaic cell.

Karp built a working prototype with just two primary optical components, thus reducing materials, alignment and assembly. This solar concentrator is compatible with high-volume, low-cost manufacturing.

"The real reason that we are trying to do this type of concentrator is certainly for cost," said Karp in an interview after winning best poster at Research Expo 2010 at the UC San Diego Jacobs School of Engineering. Karp explained that his design minimizes the cost for the optics associated with the entire system. One path to building optics very cheaply leads engineers to existing manufacturing techniques. The new solar concentrator is compatible with existing roll-to-roll processing techniques involved in fabricating large televisions.

Karp designed and built prototypes for the new solar concentrator in the Photonic Systems Integration Laboratory led by electrical engineering professor Joseph Ford from the UC San Diego Jacobs School of Engineering.

On April 15, Karp and his solar concentrator won the 2010 Rudee Research Expo Outstanding Poster Award at the 29th Annual Research Expo at the UC San Diego Jacobs School of Engineering. The National Science Foundation (NSF) and the California Energy Commission (CEC) provided some of the funding for this research.