Comparison between aesthetic and thermal performances of copper oxide and titanium dioxide nano-particulate coatings

Nano-particulate coatings with high reflectance against solar irradiation can control undesirable thermal heating by sunlight absorption. It can reduce the energy consumption for air conditioning of houses and cars. For the objects covered by these coatings and subjected to human sight, e.g. roofing surfaces, high dazzle of reflected visible light can offend the human eyes and spoil the fine view of covered objects. The authors introduced a new optimization method in designing pigmented coatings which considers both thermal and aesthetic effects in previous studies. The optimization is possible by controlling the material, size and concentration of pigment particles. The proposed coatings maximize the reflectance of near infrared (NIR) region to care the thermal effects and minimize the visible (VIS) reflected energy to keep the dark tone because of aesthetic appeal. Two different types of copper oxide pigment particles namely cupric oxide (CuO) and cuprous oxide (Cu₂O) were considered in this study. The optimum characteristics and performances are obtained and compared with titanium dioxide (TiO₂) particle as a typical cool pigment. The results show that cupric oxide has much better performance for our objective.