Farbige Deckgläser für Sonnenkollektoren

• Research unit: SFOE
• Project number: 100549

Key words (German)

TP0065;F-Industrielle Solarenergienutzung

Short description (German)

Our aim is to study the possibility of integrating dielectric multilayer films deposited on glass substrates as colored glazed covers for thermal solar collectors and building facades. The glass cover should ideally reflect only a narrow band of visible light while transmitting the rest of the sun's radiation to minimize energy losses. A compromise between the visible reflectance and the solar transmittance has to be found. In our multilayer interference filters, we combine SiO2 either with the pure oxides Al2O3 and TiO2 or the mixed oxides TiO2+SiO2 and Al2O3+TiO2 to form multilayers. All films were deposited by reactive magnetron sputtering. Insitu XPS characterization was carried out for each film. Spectroscopic ellipsometry was used to determine the optical constants and the thicknesses of every individual dielectric layer. The multilayers were characterized by their solar transmittance and visible reflectance. Transmittance and reflectance measurements of the experimentally realized dielectric multilay ers deposited on glass substrates confirm the absence of absorption and the presence of a narrow band of reflected solar light in the visible range leading to a colorful visible reflectance of 17% and a high solar transmittance of 90% for an Al2O3/SiO2 multilayer. The corresponding figures for a mixed oxide Al2O3+TiO2/SiO2 multilayer are 85 and 31%, respectively, to give just one example.

Final report (German)

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