This project is developing high-performance, solar selective coatings for power tower receivers in concentrated solar power (CSP) plants. In CSP tower systems, the receiver is where the reflected light is concentrated and converted to thermal energy. The efficiency of the light-to-heat conversion is an essential factor in determining the overall efficiency of a CSP plant. A reliable and durable solar selective coating can significantly improve efficiency by reducing the amount of light that is re-emitted away from the plant.
The research team will be using recent advances in photonic crystal fabrication and nanocomposite materials synthesis to manufacture coatings that withstand operating temperatures of 800°C while maintaining high absorptivity for visible light and low emissivity for infrared light. By engineering the selective receiver coatings at multiple length scales, the researchers are using several complementary techniques to increase the solar selectivity, ensuring that as parts of the coating degrade over time, the selectivity will remain high for long lifetimes.
This project will create a commercially-viable receiver coating that helps CSP power plants achieve a levelized cost of energy of six cents per kilowatt hour. Designing the coating on multiple scales, the team intends to create a best-in-class coating. On the smallest scale, the design uses materials that have intrinsic light absorption properties that are solar selective. These materials will be deposited within the coating on top of a larger-scale structure, fabricated by nano-self-assembly, which is physically selective for the visible wavelengths of light.