Even though solar cell technology has made great strides, certain challenges remain in the field: How do we efficiently harvest energy from sunlight at different angles from sunrise to sunset? Solar panels work best when the sun shines directly on them. To capture as much energy as possible, many solar arrays actively rotate toward the sun as it crosses the sky. This makes them more efficient than fixed systems, but they are also more expensive and complex to build and maintain.
Scientists at Stanford University in California have recently developed a new 3D-printed optical concentrator for solar panels. The pyramidal lens device, called an axially graduated refractive index lens (AGILE), was designed by engineering researcher Nina Vaidya to increase the capacity of electricity collected by solar panels while reducing their production costs and making the process more practical.
With more and more attention being paid to the planet's ecological problems today, the demand for eco-friendly energy is higher than ever, and those interested in switching to such alternatives already have a variety of different options available to them. For example, solar energy is probably one of the best known new eco-friendly energy sources that has been around for quite some time now. While there is no doubt that it is a good choice, there is still plenty of room for improvement and innvovation in its technology. A new invention that could revolutionize the way solar energy is collected was recently published in the July issue of the journal Microsystems and Nanoengineering.
In the paper, written by Stanford alumna and researcher Nina Vaidya and her doctoral advisor Professor Olav Solgaard, the scientists describe a new 3D-printed device that is capable of collecting more energy than any other solar panel before it.
How the AGILE device works
Traditional solar panels are only as good as the right circumstances. As you know, sunlight is the source of energy for this technology and must be set in the exact direction where the light can shine directly onto the panel plane. Since the direction of light changes during the day, many solar panels actively rotate in the direction of the sun to capture as much light as possible. However, with the newly introduced device, this lengthy and elaborate procedure may soon become redundant. Thanks to its special construction, this innovative panel structure is capable of capturing and focusing sunlight from any angle and is shaped like a tipless inverted pyramid. The material, a combination of glass and polymer, allows the lens to concentrate solar energy from different angles in one place, similar to how you would light hay with a magnifying glass.
Nina Vaidya explains, "We wanted to create a device that could absorb light and concentrate it in the same place, even when the light source changes direction. We didn't want to have to constantly move our detectors or solar cells, or move the system to face the light source. This is a completely passive system - it requires no energy to track the light source, and there are no moving parts. Without the optical focus of moving positions or the need for a tracking system, concentrating light becomes much simpler."
In the prototype device they developed, the researchers were able to capture more than 90 percent of the light hitting the surface and produce spots of light at the output that were three times brighter than the incident light. Installed in a layer on top of the solar cells, they increase the efficiency of the solar panels, capturing not only direct sunlight but also diffuse light scattered by the Earth's atmosphere, weather and seasons. the top layer of AGILE can replace the existing package protecting the solar array, eliminating the need to track the sun, creating space for cooling and circuitry to operate between the narrow pyramids of individual devices. Most importantly, reducing the cell area needed to generate energy from the sun, thereby reducing costs. And the uses are not limited to terrestrial solar installations: if applied to solar arrays being sent into space, the AGILE layer can both concentrate light without solar tracking and provide the necessary radiation protection.
Not much is known about the exact 3D printing technology used to create this new type of panel. However, the way the panels are made is by layering different glass and polymers together to bend the light to varying degrees, ultimately focusing the light in exactly one place. After a long trial-and-error phase and the production of many different prototypes, Nina Vaidya is now confident that her design will soon be successfully used in the solar industry and beyond. She concludes, "It is very rewarding to be able to use these new materials, these new manufacturing techniques and this new AGILE concept to create better solar concentrators. Abundant, affordable, clean energy is an essential part of meeting the pressing climate and sustainability challenges, and we need to catalyze engineering solutions to make this a reality."