In the relentless pursuit of cleaner, more efficient energy solutions, researchers at the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) have made a significant breakthrough in solar technology. Led by Salvatore Esposito at the Portici Research Centre, the team has developed a new solar selective absorber coating (SSAC) that promises to enhance the efficiency and durability of Concentrated Solar Power (CSP) systems. This innovation, published in the journal ‘Energies’, could revolutionize the way we harness solar energy, making it more competitive and reliable.
CSP technology, which uses mirrors to concentrate sunlight and generate heat, has long been touted as a key player in the future of clean energy. However, its widespread adoption has been hindered by high costs and the need for components that can withstand extreme temperatures. The new SSAC, designed to operate at 550°C, addresses these challenges head-on. By incorporating silver as an infrared reflector, the coating significantly reduces thermal losses, a critical factor in improving the overall efficiency of CSP systems.
The challenge with using silver is its high diffusivity, which can compromise its performance at high temperatures. To overcome this, the ENEA team introduced a novel approach: enclosing the silver reflector with stabilizing layers. “One W stabilizing layer was placed between the substrate and the Ag infrared reflector, whereas a second stabilizing layer, selected among aluminum nitride deposited with a low and high nitrogen flow and aluminum oxide deposited at a low oxygen flow, was placed between the Ag infrared reflector and the solar absorber,” explains Esposito. This innovative design ensures that the silver reflector remains stable and effective, even at the high operating temperatures required for CSP systems.
The results are impressive. Accelerated aging tests revealed negligible degradation of solar absorptance, and the hemispherical emittance at 550°C increased by only a fraction of a percent. This means the coating can maintain its performance over a projected 25-year service life, a crucial requirement for reducing operating and maintenance costs.
The commercial implications of this research are vast. CSP plants equipped with these advanced SSACs could see a significant boost in efficiency, potentially increasing energy production by 5 to 10% for each percentage point reduction in hemispherical emittance. This could make CSP technology more competitive with other renewable energy sources, driving down costs and accelerating its adoption.
The ENEA team’s breakthrough is a testament to the power of innovation in the energy sector. By pushing the boundaries of material science and engineering, they have developed a solution that could reshape the future of solar energy. As the world continues to seek sustainable and efficient energy solutions, this research offers a promising path forward, one that could see CSP technology playing a pivotal role in our energy landscape.