Solar concentrators

New Concentrator Helps Solar Panels Absorb More Sunlight Without Tracking It

Solar panels will aid sustainable energy generation. However, their efficiency is limited unless they receive direct sun radiation exposure. These issues can arise when the sun is obscured by cloud cover or as it rises and sets over a day.

Many rotating solar arrays can capture the sun’s rays. However, because of this, they are more expensive to develop and operate than those that remain stationary.

While shifting solar panels is still an option, a new device developed by an engineering researcher can concentrate three times as much light that falls on it, capturing 90% of the light that falls on it regardless of angle or frequency.

Microsystems & Nanoengineering has published the findings.

There are no moving parts or energy requirements to track the source, says first author Dr. Nina Vaidya, who completed the research at Standford University in the United States and is now an assistant professor in astronautics and spacecraft engineering at the University of Southampton in the United Kingdom.

Focusing on light becomes considerably more manageable if you don’t need tracking systems.

When you look at it, it appears like an upside-down glass pyramid with the point chopped off. It’s called AGILE, which stands for axially graded index lens.

The magnifying glass-like effect works similarly to how it concentrates light into a smaller, brighter area on a sunny day. When you want to focus sunlight on a specific location of a photovoltaic cell throughout the day, however, a magnifying glass’s focal point moves with the sun, which isn’t ideal.

At the bottom of a photovoltaic cell, the thin base of AGILE is brighter because light enters from all directions and is funneled down to the photovoltaic cell, generating a more promising area.

We wanted to design something that could focus light at the exact location no matter which way the light source was moving, says Vaidya. To avoid constantly turning our detector or solar cell around to face the start, we designed our system to be as stationary as possible.

In the words of senior author Olav Solgaard, a Stanford electrical engineering professor and Vaidya’s doctorate advisor, “A perfect AGILE has the same refractive index as air, and it steadily rises so that light bends in a perfectly smooth curve.

There is no such thing as an ideal AGILE in the real world.

A graded-index material, on the other hand, is used to construct the prototype AGILE. This material comprises various layers of glasses and polymers that bend light in different directions. These layers gradually alter the direction of the entering light until it is almost vertically aligned with the output.

Commercially available materials that could enable a wide range of light to flow through, bend it towards the output, and be compatible with each other were among the most challenging aspects of developing the AGILE prototype.

The glass that expands at different rates in reaction to heat might cause the entire device to break. Additionally, the materials must be strong enough to be machined into shape and last for an extended period.

The prototypes’ sides are also mirrored to return any light traveling in the wrong direction to the foundation.

Instead of the current encapsulation that protects the solar arrays, these AGILE devices may be put on top of the solar cells, replacing them and providing additional room for cooling and circuitry to be routed between the narrowing pyramids of the individual gadgets.

To put it another way, “creating better solar concentrators by combining new materials, new production techniques, and this new AGILE concept has been satisfying,” says Vaidya.

“The pressing climate and sustainability concerns necessitate an abundance of inexpensive renewable energy, and we need to accelerate engineering solutions to make that a reality.”

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