Self-Cleaning Solar Mirror Coatings: From the Laboratory Scale to Prototype Field Tests

• Published in: Applied sciences Vol. 14; no. 15; p. 6669
• Main Authors: Castaldo, Anna, Gambale, Emilia, Vitiello, Giuseppe, Cara, Giuseppe
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2024
• Subjects: AlN; Aluminum compounds; coatings; Contact angle; Equipment and supplies; Field study; Green technology; Laboratories; Laboratory equipment; Nitrides; Plasma etching; Protective coatings; prototype; Prototypes; self-cleaning; Solar energy; Solar energy industry; solar mirrors; sputtering; Italy; Germany
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app14156669

In this study, a low-cost, scalable and robust process is proposed as an innovative method for coating solar mirrors with a self-cleaning, transparent in the full solar range and versatile material based on auxetic aluminum nitrides, previously obtained at the laboratory scale. This work presents the scaling-up of the fabrication process from the laboratory to prototypal scale and the preliminary results of outdoor self-cleaning solar mirror field tests in the demonstrative concentrating solar power (CSP) plant ENEASHIP located in Casaccia (Rome) ENEA Research Center. Prototypes with a size of 50 × 40 cm have shown stability in external conditions: no coating degradation occurred during the test campaign. Their washing restores the initial reflectance affected by soiling and the self-cleaning performance allows for the utilization of a reduced quantity of water for cleaning operations with respect to the uncoated glass of back surface mirrors. A similar self-cleaning AlN coating could be utilized on other solar components affected by soiling, such as the glass envelopes in heat-collecting elements, PV panels and other parts where a self-cleaning performance combined with an optical one is required.