Review Paper on Selective Coating of Absorber Tube for Parabolic Trough Collector.

This paper describes the various coatings used for absorber tube of Parabolic Trough Collector (PTC) and their properties. Solar thermal selective absorber coatings are currently characterized by their solar absorptance and their thermal emittance. Mostly coating is by electroplating, paint coatings and deposited cermet. This paper mainly focus on properties of Black chrome, Black Nickel , Black cobalt, Black-colored CuFeMnO4 spinel powder, Thickness-sensitive spectrally selective (TSSS) paint coating, spray-coated graphitic films and there manufacturing process. The coatings need to be stable in air in case the vacuum is breached. Current coatings do not have the stability and performance desired for moving to higher operating temperatures.