Solar panels are becoming an increasingly important source of renewable energy. Still, they need to be improved as they only work in direct sunlight since many batteries are only capable of delivering power for a few clear hours a day – and solar pyramids can be of great help here.
Engineers from Stanford University (USA) decided to correct this problem and developed a pyramid-shaped lens that can focus light from any angle onto a solar cell, allowing it to store energy from sunrise to sunset.
The team developed an inverted pyramid-shaped passive technology called the Axial Index Lens (AGILE). The little pyramid is made up of a stack of different glasses and polymers—essentially, each layer refracts incident light to an other degree. All layers were 3D printed.
The top layer allows light to enter from any angle, but each successive layer bends the beam until it focuses on the solar cell. The layering of the device also allows it to capture a broad spectrum of light, from near-ultraviolet to infrared.
In testing, AGILE prototypes could capture more than 90 percent of the light that hits the lens surface and focus it to be three times brighter. The system dramatically increased the efficiency of the solar panels, allowing them to collect indirect sunlight, and increasing their output in less-than-ideal conditions.
After achieving success, the team explained that the new system of solar pyramids will help harvest solar energy more efficiently, and AGILE can even improve solar panels for spacecraft.