Spectrally selective absorber coating for solar receivers operating in air
The invention allows the production of innovative solar absorber coatings stable in the air and at operating temperatures above 400 ° C. This is achieved by using one or more structures capable of protecting the metal components of the solar absorber coating from atmospheric oxidizing agents.
These air-stable solar absorber coatings, stable also at temperatures above 400 °C, are made using structures capable of protecting the coatings’ metal components. Each protective structure comprises of a metal alloy and a ceramic layer, placed onto the metal one. The two layers, thanks to their well-defined compositional, stoichiometric and structural characteristics, allow, when heated in air at high temperatures, the formation at the metal alloy-ceramic layer interface of an extremely thin, stable and compact oxide layer that behaves as an effective barrier to the diffusion of oxidizing agents present in the atmosphere towards the metal components of the coating. The spectrally selective absorber coating allows the implementation of an innovative receiver tube operating in the air and, therefore, of significantly lower cost than evacuated receiver tubes, efficient and reliable at operating temperatures of 400 ° C and above, for which they are not currently available commercial products.
- Absorber coatings for receiver tubes operating in air for concentrating solar thermal and thermodynamic plants with linear parabolic or Fresnel collectors.
- Production of receiver tubes operating in air at temperature above 400 °C;
- Cost reduction and technological robustness improvement of the receiver tube;
- Use of the sputtering deposition technique to realize the entire solar absorber coating.