Impact of Solar Selective Coating Ageing on Energy Cost

Abstract

Abstract In order to overcome the current energy challenges and to find new ways of producing clean energy, the solar sector is focused on improving its performance and defining the adequate technology for each application. Nowadays the concentrated solar power (CSP) technology, which uses parabolic trough collectors, is the most mature and well-established concept. The technology is based on the concentration of solar radiation using parabolic reflective surfaces (typically glass mirrors) and focusing the collected energy on a receiver tube, which is placed on the geometrical focus of the parabola. Solar selective coatings are applied on the surface of the receiver tube surface to improve its performance in stable conditions, but these nanocoatings suffer stresses during their operating lives, which reduce their optical properties and increase the cost of the produced energy. The development of selective coatings with improved optical properties is essential to the development of CSP technology. It requires improvements in the process of layer deposition, to enhance the characterization of the coating optical properties, and to monitor the coating status during the typical 25 years of operation. In this study it has been analyzed the impact of the ageing of selective coating in the energy gain and thermal losses and, as a consequence, the necessary evolution of CSP technology to reduce the cost of energy.