Stanford University researchers have developed a new device called Axially Graded Index Lens (AGILE) that could revolutionize the solar panel industry. The device, which appears to be nothing more than an inverted glass pyramid, can concentrate diffused light from any angle and direct it to a single point on the solar panel, increasing its power generation capacity.
Solar panels work best when sunlight is directly incident on them. In order to maximize the amount of sunlight available, scientists have relied on solar tracking systems that move panels in sync with the Sun as it moves across the sky. However, these systems increase the cost of deploying solar panels, making it a barrier to their widespread adoption.
The AGILE device solves this problem by eliminating the need for solar tracking systems and optical focus that moves positions. It works by bending incoming light and directing it to a single point on the panel, making it much simpler to concentrate light. The device is completely passive and doesn’t require any energy to track the source or moving parts.
Doctoral supervisor Olav Solgaard and researcher Nina Vaidya theorized that an engineered material with a smoothly increased refractive index could bend incoming light and direct it to a single point. The refractive index measures the speed at which light travels through a material. In the AGILE device, light is bent slightly at the surface, but as it travels through the device, it is bent until it becomes almost vertical.
The researchers experimented with various materials, including glass and polymers, to create the device with a graded refractive index. The prototypes also had mirrors on their sides to redirect any escaping light. However, using a mix of materials had the disadvantage of potentially cracking under different levels of heat expansion.
