Microstructuring technology for large and cylindrical receivers for concentrated solar plants (CSP)

This paper presents an innovative fabrication process of microstructured spectrally selective solar absorbers for concentrated solar power (CSP) plants. The authors describe suitable technologies and methods to microstructure large areas and non-conventional substrates, such as tubes, and substrates with large surface areas typically used in CSP plants. Specific colloidal lithography combined with layer deposition makes it possible to structure this type of substrate with a submicron periodicity within a hexagonal arrangement. Appropriate techniques, e.g. Langmuir-Blodgett deposition and customized UV insolation were developed to process 80 mm diameter and 300 mm long tubes and 300 × 300 mm2 planar substrates. Absorbing and anti-reflection coatings were deposited using industrial vacuum deposition equipment with three different deposition sources: PECVD, magnetron sputtering and cathodic arc deposition. The design and assessment of the efficiency of the microstructure absorbing layers on smaller planar substrates are described elsewhere, assuming that optical performances are close to the large and tubular substrates. The technological processes and the resulting demonstrators are described in detail herein. [Display omitted] •Microstructuring technology for selective absorbers used in CSP plant.•UV Colloidal lithography adapted to non planar and large receivers.•Nanostructured absorbers are made by photolithography followed by PVD steps.•Experimental results showed absorption over the whole solar spectrum increased from 95% to 96.6% with microstructured coatings.