Advanced mirror concepts for concentrating solar thermal systems

Abstract

Collectors used in concentrating solar thermal (CST) technology include large mirrors or reflecting surfaces that reflect the incoming radiation onto a focus, where the solar receiver is placed. The collectors' efficiency strongly depends on the reflector material. As a consequence, research institutes, mirror manufacturers, and CST plant developers are paying special attention to the evolution and advances in the solar mirror technology. Significant advances marketed in the last 7 years or currently under development include anti-soiling coatings to decrease the amount of adhered dust particles during plant operation (and therefore the cleaning costs), highly reflective mirror materials that increase the plant efficiency through higher flux onto the absorber, and high-temperature mirrors that are able to withstand the working conditions encountered by secondary concentrators (which improves the plant efficiency by both increasing and homogenizing the solar flux and by reducing the receiver size).