Design and fabrication of spectrally selective absorber coatings for high temperature solar thermal power applications
Subcategory (under Clean Energy): Solar (Thermal)
Technology Readiness Level (TRL): TRL 4 - Early prototype
Technology Outline (Process Description)
A novel spectrally selective tandem stack of W/WAlSiN/SiON/SiO2 was deposited on stainless steel 304 and silicon substrates using a four-cathode reactive unbalanced magnetron sputtering system. In the tandem stack, W layer acts as an IR reflector, WAlSiN acts as the main absorber layer, and SiON, and SiO2 layers act as anti-reflecting layers. The tandem stack was designed based on graded refractive indices of individual layers with a double layer anti-reflection coating. The tandem stack exhibits superior spectral selectivity with a high solar absorptance of 0.955 in the broadband solar spectrum region and low thermal emissivity of 0.10 in the infrared region. Thermal stability studies indicate that the as-deposited samples were thermally stable in air up to 550 ᵒC for short duration and 400 ᵒC for long duration. The coating was found to be thermally stable up to 700 ᵒC in vacuum for 200 hrs under cycling heating conditions. The developed coating is an ideal candidate for receiver tubes for high temperature solar thermal applications.
Salient Features/Advantages
- Indigenously developed process, which is a closely guarded technology.
- Eco-friendly coating process.
- Harvesting of solar energy for industrial applications, including electricity generation.
Key Outcomes
- In an effort to meet ever increasing energy demands of the country, under this DST funded project, an indigenous solar absorber coating with outstanding optical properties and thermal stability suitable for generating electricity from cost effective photothermal conversion route was developed. This coating development is a part of developing an eco- system in the country for generating electricity from solar energy.
- of publications: 8 SCI
- HR Training: Ph. D. – 1, B. E. – 3.
IP Protection details
- Patent filed (Title, national/International): Nil
- Patents Granted: Nil.
- Copyrights obtained /progress on commercialisation /Pl. specify connect with industry: Nil.
Contact details (for more information)
- Nodal Person name: Dr Harish C Barshilia
- Email ID: harish@nal.res.in
- Organisation name (Relevant link/web page): CSIR-National Aerospace Laboratories, Bangalore
Supporting Photographs/Images
Organizations involved in the development (logo/name) CSIR – National Aerospace Laboratories, Bangalore – 560 017 |