An engineering team at the University of California, San Diego has developed a new nanoparticle-based material for concentrating solar power plants which can absorb and convert to heat more than 90% of the sunlight falling on it. Unlike materials currently in use, the new material can withstand temperatures of more than 700ºC and survive for many years.
Most current solar thermal plants use thousands of mirrors to aim sunlight at a tower that has been painted with a light absorbing black paint material. The material is designed to maximize sunlight absorption and minimize the loss of light emitted from the surface in the form of infrared radiation.
However, the high temperatures degrade the material such that the plants have to be shut down about once a year to chip off the degraded material and apply a new coating; no power can be generated while the replacement coating is applied and cured.
The University of California team has developed a material using particles ranging in size from 10 nanometers to 10 micrometers. When spray-painted onto a metal substrate, these particles form a “multiscale” surface which is able to withstand temperatures in excess of 700° C and years of exposure to air and humidity while trapping and absorbing 90 to 95% of light.