THICKNESS INSENSITIVE SPECTRALLY SELECTIVE (TISS) PAINT COATINGS FOR GLAZED AND UNGLAZED SOLAR BUILDING FACADES

摘要

Spectrally selective paint coatings have been always considered as cheap but not high energy efficient coatings for solar thermal. Coil coated black paint (Solarect) developed previously at NIC is now used as a Thickness Sensitive Spectrally Selective (TSSS) coating for the solar absorbers with a well controlled thickness of about 1 - 2μm. Paints with a spectral selectivity independently to the thickness (Thickness Insensitive Spectrally Selective (TISS) coatings) avoid the problems connected to the coil coating application and the related thickness control of the coatings,. TISS paints possess intrinsic spectral selectivity due to the metallic flakes added to the resin binder assuring low emittance of the paint. The paint can be applied by spraying or brushing, even to the non-metallic substrates. During the last few years, the concept of the building solar facades is coming up more and more. The solar building facade should simultaneously fulfil two opposite demands: the energy efficiency of the solar facade system and nice appearance. Black absorbers are therefore not acceptable and absorbers with other shades of colours should be used. Perfect solution does not exist because coloured coatings have inherently lower solar absorptance as compared to the black coloured ones. High energy efficiency must be sacrificed although it could be at least partially compensated by the spectral selectivity of the coloured coatings.