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Title: Durability of Solar Reflective Materials with an Alumina Hard Coat Produced by Ion-Beam-Assisted Deposition: Preprint

A promising low-cost reflector material for solar concentrating power (CSP) generation is a silvered substrate protected by an alumina coating several microns thick. The alumina hard coat is deposited under high vacuum by ion-beam-assisted-deposition (IBAD). Samples of this material have been produced both by batch and continuous roll-coating processes. The substrate materials investigated were polyethylene terephthalate (PET), PET laminated to stainless-steel foil, and chrome-plated carbon steel strip. The advantage of steel strip compared to PET is that it withstands a higher process temperature and lowers the final product installation costs. In this paper, we compare the durability of batch and roll-coated reflective materials with an alumina deposition rate as high as 10 nm/s. In general, the durability of the samples is found to be excellent. Comparisons between accelerated and outdoor exposure testing results indicate that these front-surface mirrors are more susceptible to weather conditions not simulated by accelerated tests (i.e., rain, sleet, snow, etc.) than other types of solar reflectors. For long-term durability, edge protection will be necessary, and durability could be improved by the addition of an adhesion-promoting layer between the silver and alumina.
Authors:
;
Publication Date:
OSTI Identifier:
15002207
Report Number(s):
NREL/CP-520-32824
TRN: US200408%%167
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Oct 2002; Related Information: Prepared for the 2002 AIMCAL Fall Technical Conference, 16th International Vacuum Web Coating Conference, 21-23 October 2002, Sedona, Arizona
Research Org:
National Renewable Energy Lab., Golden, CO. (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 14 SOLAR ENERGY; CARBON STEELS; COATINGS; DEPOSITION; MIRRORS; POLYETHYLENES; RAIN; SILVER; SNOW; SOLAR REFLECTORS; STEELS; SUBSTRATES; TESTING; WEATHER PV; SOLAR CONCENTRATING POWER (CSP); ALUMINA HARD COAT; ION-BEAM-ASSISTED DEPOSITION; REFLECTOR MATERIAL; LOW-COST; DURABILITY; ACCELERATED TESTING; CAGE PROTECTION; POLYETHYLENE TEREPHTHALATE (PET); SOLAR ENERGY - PHOTOVOLTAICS