This study describes nanoparticles pigmented coatings used in controlling the radiative properties of surfaces exposed to sunlight. An optimization method that embraces both thermal and aesthetic requirements has been proposed. The proposed coatings maximize the reflectivity of the near infrared (NIR) region to reduce thermal heating, while for aesthetic appeal they minimize the visible (VIS) reflected energy. This spectral behavior can be achieved by controlling the size and concentration of pigment particles and coating thickness. In this study, both experimental and numerical approaches are applied on Fe2O3 pigmented coating samples with 0.2 μm and 1 μm of average particle size and different particle concentrations and coating thicknesses. For numerical part the radiation analysis using the Radiation Element Method by Ray Emission Model (REM2) in a one dimensional parallel plane model is conducted. From the numerical results, it is shown that the optimum size of Fe2O3 particles for our desired spectral behavior is about 0.8 μm. The experimental results also show that the samples made from 1 μm particles have better performance for our objective.

Volume Subject Area:
Fundamentals of Heat and Mass Transfer
Topics:
Coatings, Nanoparticles, Particulate matter, Radiation (Physics), Emissions, Heating, Optimization, Particle size, Reflectance, Sunlight, Surface properties
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Copyright © 2011
 by ASME
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