Improving optical properties of diffusion-based absorber coatings for CSP tower systems

Abstract

In the course of energy transition the development of sustainable, efficient and renewable technologies for power generation providing base load supply is of crucial importance. CSP plants have great potential to fulfil all these requirements. However, mitigation of molten salt corrosion inside the absorber tube as well as improvement of optical properties on its outside are key challenges and part of ongoing developments. For this purpose, a Cr-Mn-diffusion absorber coating has been developed and is presented together with its improved version, an organic-based bilayer system. This study focusses on the continuous improvement of optical properties in terms of thermal efficiency (solar absorption and emittance) as well as qualification of both coatings with regards to long term durability (isothermal and thermocyclic stability).