Researchers at the University of Wisconsin Madison have developed a new solar power system that is inspired by the sun-catching behavior of sunflowers and is at least 10 percent more efficient than conventional solar panels. The inspiring behavior is an adaptation called heliotropism -- the tracking of the sun throughout the day by sunflowers and other plants by slowly rotating and positioning each leaf to grab the most sunlight.
There are many other solar power systems out there that use GPS and motors to reposition the solar panels throughout the day, but this new system is different because it uses cutting-edge materials to take a more passive approach to catching sunlight.The engineers used a fairly new material called liquid crystalline elastomer (LCE) that contracts when exposed to heat. Coupled with carbon nanotubes that are able to absorb a wide range of light wavelengths all the way to infrared, the system is essentially driven by the unique properties of the materials it is made with, just as sunflowers naturally and effortlessly track the sun.
The university explains, "Direct sunlight hits a mirror beneath the solar panel, focused onto one of multiple actuators composed of LCE laced with carbon nanotubes. The carbon nanotubes heat up as they absorb light, and the heat differential between the environment and inside the actuator causes the LCE to shrink. This causes the entire assembly to bow in the direction of the strongest sunlight.
As the sun moves across the sky, the actuators will cool and re-expand, and new ones will shrink, re-positioning the panel over the 180 degrees of sky that the sun covers in the course of the day."
The benefit of a passive system like this that there is no energy required to drive it, so none of the energy it generates is eaten up by the system itself -- it's all usable energy. As lead engineer Hongrui Jiang says, "The whole point of solar tracking is to increase the electricity output of the system."
Right now the system is just in the proof-of-concept phase, which you can watch demonstrations of in the videos below, but Jiang and his team are working on creating larger panels using the technology so that huge fields of solar panels can one day passively rotate along with the sun.