University of San Diego engineers have developed a nanomaterial that dramatically enhances the collection of solar energy in concentrating solar plants.
The material has been dubbed the “black hole”, due to its enormous ability to absorb solar energy.
The team were challenged as part of the U.S. government’s SunShot program to increase the efficiency of large-scale concentrated solar power (CSP) technology, which involves thousands of reflectors focusing sunlight onto a single collection point, called a solar absorber. The immense heat produced boils steam to drive an electric turbine. Conventional solar absorbers rapidly break down under the strain, requiring lengthy and costly delays while they are replaced.
By contrast, the UCSD team’s nanotech absorber is capable of converting to heat over 90 per cent of sunlight it captures and is designed to withstand extreme temperatures of over 700 degrees Celsius for years, despite exposure to the elements. Their work is published in the journal, Nano Energy.
“We wanted to create a material that absorbs sunlight that doesn’t let any of it escape. We want the black hole of sunlight,” said Sungho Jin, a professor in the department of Mechanical and Aerospace Engineering at UC San Diego Jacobs School of Engineering
To achieve this black hole effect, Jin and his colleagues created a “multiscale” surface using silicon-boride nanoparticles ranging in size from 10 nanometres to 10 micrometres. When sunlight hits the material, it is trapped and absorbed in the multiscale surface more efficiently than the black paint material used in conventional CSP plants.
The team have fabricated a spray-on application method for delivering the material onto a metal substrate in laboratory conditions and say they are close to ensuring the material will last for years in humidity and the open air.
“Current CSP plants are shut down about once a year to chip off the degraded sunlight absorbing material and reapply a new coating, which means no power generation while a replacement coating is applied and cured,” the University stated.
“The UC San Diego research team is aiming for many years of usage life, a feat they believe they are close to achieving.”
