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New solar material converts 90% of captured light into heat

Scientists have created the ‘black hole of sunlight’ - a new nanoparticle-based material that absorbs and converts more than 90 percent of captured sunlight to heat.

SCIENCEALERT STAFF
1 NOV 2014
 

Research from the US have developed a super-Sun-absorbing material that will help concentrating solar power (CSP) plants to generate more electricity and run for longer - a huge step towards making solar a viable alternative to fossil fuels.

Traditional power plants burn coal or fossil fuel to create heat in the form of steam. This steam then turns a giant turbine that generates electricity from spinning magnets and conductor wire coils. One of the most promising clean energy technologies are CSP plants, which create the steam needed to turn the turbine by using sunlight to heat molten salt. 

 

A world-first CSP plant in Australia has already proved that the steam generated by solar power is pressurised and hot enough to match that produced by fossil fuels.

Most CSP plants generate energy by using hundreds of thousands of large, reflective mirrors that concentrate sunlight at a tower that has been painted with a light-absorbing black paint material. Importantly, this electricity generated from the power of the Sun can be fed directly into our existing grid, and, because the mirrors can be used to concentrate light even on cloudy days, it overcomes many of the issues of solar panels.

But one downside is that the material that is currently used degrades quickly and needs to be reapplied once a year, meaning that CSP plants are shut down and no power can be generated in this time.

To combat this problem, scientists have developed a material that has a longer life cycle and allows for greater conversion of captured sunlight into heat. 

Researchers from the University of California in the US created the new “multiscale” material by covering it in thousands of scale-like particles ranging from 10 nanometres to 10 micrometres. The material can withstand temperatures greater than 700 degrees Celsius, allowing it to more efficiently trap and absorb sunlight.

It can also tolerate exposure to air and humidity, enabling it to survive for many years in the outdoors. More importantly, these unique properties allow the material to convert more than 90 percent of captured sunlight to heat.

"We wanted to create a material that absorbs sunlight that doesn't let any of it escape," said Sungho Jin, engineer and one of the researchers, in a press release. "We want the black hole of sunlight."

CSP plants can produce around 3.5 gigawatt-hours of power per year, which is enough to power more than 2 million homes. The technology can easily retrofit existing power plants, as both use the same process to generate electricity.

The team are continuing their research by further extending the usage life of the material, and hope that the breakthrough will finally prove that solar is not only a cheaper and more sustainable source of energy than fossil fuels, but also that it's more efficient.

The findings are published in the journal Nano Energy.

Source: EurekAlert

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