Phosphoric acid based solar absorber coatings
Solar thermal energy technology has become a successful part of today's world's energy supply. It is a growing field with new applications and better equipment designs every year. High-performance solar heating depends on improved coatings that are designed to maximize absorption and minimize reflection of the sun's radiant heat. Solar absorber coatings for applications such as solar domestic water heating are already available; however the cost and energy efficiency can be improved. This improvement can be made by minimizing cost if solar absorber coatings can be applied to steel at low cost. The work conducted in this thesis research was intended to improve the phosphoric acid base coating which was produced by Bhargava Reddy Vantari and Dr. Roy Arrowood in 2007 at the University of Texas at El Paso and shown to improve the solar heat absorption performance of a steel surface. The improvement was achieved by adding additional elements (copper or zinc) to the phosphoric acid based solution, which was used to coat the steel surface. Vantari and Arrowood devised a new and very simple test method for preliminary comparison of the heat absorption performance of different solar absorber coatings. In the present thesis research, that method was then enhanced and used to compare the solar heat absorption performance of the improved coatings. Compared to the bare steel surface, the un-doped, coated sample absorbed solar heat 56% more rapidly. The zinc-doped, coated sample absorbed heat 70% more rapidly than the bare steel, and the copper- doped, coated sample absorbed heat 83% faster than bare steel. After application and solar testing, the coatings were characterized by different analyses which include; Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Electron Dispersive X-Ray Spectroscopy (EDS).^
Gallegos, Flor Gabriela, "Phosphoric acid based solar absorber coatings" (2013). ETD Collection for University of Texas, El Paso. AAI1545160.