Sol-Gel-Derived AR Coatings for Solar Receivers

摘要

This report details a process for applying sol-gel antireflection (AR) coatings to solar receiver envelopes. The process consists of applying a porous film which is subsequently etched to achieve the optimum AR effect. The result is a single-layer interference film with a reflectance minimum at 550 nm. The solar transmittance of coated tubes is typically increased to 0.95 to 0.97, as compared with 0.91 for uncoated tubes. Coated tubes showed no significant decrease in solar transmittance after 16 weeks of operation in a parabolic trough collector system. Recommendations are included for process improvement before industrial scale-up. (ERA citation 10:000438)