Stacks of tiny lenses that look like inverted pyramids can suck up solar panels, allowing them to capture more light from every angle on both sunny and cloudy days.
Solar panels perform best in direct sunlight. Therefore, some solar systems track the great fireball across the sky, turning it toward the sky for maximum light. Unfortunately, such tracking technology is pricey and moving parts can break.
Shortcomings such as these motivated Stanford researchers to develop an alternative. The resulting technology – called Axially Graded Index Lens or AGILE for short –provides a way to increase the efficiency of static solar panels, even in diffused light, said authors Nina Vaidya and Olav Solgaard in a peer-reviewed article† prototype arrays of AGILE lenses successfully concentrated the light in a 3x smaller area, retaining 90% of its power at best, and well ahead of more basic concentrators when the light was more oblique (sometimes concentrators can increase the light intensity sacrifice but come for the gathering corner).
Concentrating light to squeeze more energy from solar panels is not new, but the authors point out that concentrators such as fresnel lenses and mirrors only offer”modest acceptance angles.” Incidentally, the pyramidal design also manages to look glamorous in a render video released next to the paper.
The prototype of the AGILE lens shown in three stages of development. A: Bonded glass. B: with aluminum side walls. C: with a solar cell that absorbs light.
The internet is littered with great ideas that can help us capture more energy from the sun. Many are inspired by things in nature, such as: butterfly wings† fly eyes† petals even Puffer fish† The design for AGILE “didn’t come from nature,” according to Vaidya, but the paper acknowledges that “there are features of AGILE that can be found in the retina of fish (eg. Gnathonemus) and compound eyes in insects (e.g lepidoptera), where a gradient index is present as anti-reflection to maximize transmission and allow camouflage.
While the studies did not announce plans to bring AGILE to market, the prototypes were designed with the solar industry in mind using readily available materials, according to a Stanford press release.
“Abundant and affordable clean energy is an essential part of tackling the pressing climate and sustainability challenges,” says Vaidya. “We need to catalyze technical solutions to make that happen.”