Issue and Challenges with High-Temperature Solar Selective Material for Solar Thermal Application

Solar selective coatings (SSC) are integral part of the receiver in any concentrated solar thermal system for efficient conversion of incident solar energy into thermal energy. The most common solar thermal systems are based on parabolic trough collectors, which are operating at 350 degrees C. Thus, the absorber coating should be robust and efficient to operate at such temperatures without any degradation. There are limited such solar selective coatings and very few are commercially available. These are cermet based structure and are stable at high temperature in vacuum. These structures are prone to chemical reaction in open-air condition, which results in degraded optical performance of SSC structures. Thus, there are issues and challenges in SSCs, especially for higher operating temperatures, which is essential to realize the higher efficiency of solar thermal systems. The work is focusing on such constraints towards realizing high temperature solar selective coatings.