IMPACT OF ANGULAR SOLAR ABSORPTANCE ON COLLECTOR PERFORMANCE INVESTIGATED BY DYNAMIC COLLECTOR TESTING AND OPTICAL ANGULAR CHARACTERIZATION OF SOLAR ABSORBERS

摘要

The purpose of this study was to investigate how the angular solar absorptance of the soIar absorberrninfluences the efficiency of the whole solar thermal collector. Two types of absorbers (aluminum strip with eitherrnnickel-pigmented anodic aluminum oxide coating or nickelickel oxide coating) were tested in the same type ofrncollector box. The collectors were evaluated according to the principle of dynamic testing. This evaluation showedrnno significant difference in yearly energy output between the two absorbers. The optical evaluation of the angularrnsolar absorptance was made from angular spectral reflectance using an optical measuring system equipped with anrnintegrating sphere. The measurements showed a better optical performance of the nickel-pigmented aluminum oxidernabsorber at higher angles of incidence, but this effect is reduced by the glazing. This result is confirmed by therndynamic testing.