| Autor: |
Z. Crnjak Orel, R. Jerman, M. Hodošček, B. Orel |
| Rok vydání: |
1990 |
| Předmět: |
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| Zdroj: |
Solar Energy Materials. 20:435-454 |
| ISSN: |
0165-1633 |
| DOI: |
10.1016/0165-1633(90)90034-x |
| Popis: |
The background to the spectral selectivity of thickness sensitive spectrally selective (TSSS) paint coatings is discussed from the chemical point of view. This means considering the solar absorptance (as) and thermal emittance (eT) of the TSSS paint coatings as a function of paint film thicknesses in terms of the degree of flocculation of the pigment dispersion and from the viewpoint of the relevant intermolecular interactions which influence the ability of the pigment particles to become distributed uniformly in the paint, thus increasing its colour strength. We investigated eight TSSS paint coatings based on the standard formulation of Solariselect® paint [Sol. Energy Mater. 18 (1989) 97], which is currently used for solar collector panels. The influence of carbon soot (C - Degussa FW2), inorganic pigment (F - Ferro 6331) and fumed silica thixotropic agent (Aerosil - Degussa) in TSSS paint coatings on the degree of their flocculation was determined from the infrared hemispherical reflectivity R (d)λ = 2.5 which was measured from the paint film thickness. The absorption coefficient for diffuse radiation (K) and the scattering coefficient (S) were determined by fitting the experimentally determined R (d)λ = 2.5 curves to a modified Kubelka-Munk function derived by Korte and Otto [Appl. Spectrosc. 43 (1988) 38]. Correlations between the type of black pigment (F and C) and elementary particle size and surface activity of fumed silica (Aerosil 380, 200 and 972) were established and compared with the experimentally determined solar absorptance values (as) of the corresponding TSSS paint coatings. Since fumed silica in spite of its small content ( |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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