Numerical and experimental study on a double-layered coating design using supplemental property particles for achieving user-desired thermal and aesthetic performance

Existing studies have demonstrated that coating is highly effective in improving building energy efficiency. In practice, coating design requires performance considerations in both thermal and aesthetic aspects. For a single type of particle, such performance requirement is conflicting and difficult to fulfill. For instance, the commonly used TiO₂ particle can perform well in the thermal aspect but poorly in the aesthetic aspect. Adopting supplemental property particles, coatings may have potentials to meet such conflicting performance requirement. Considering the potentials, this study proposes a double-layered coating design using two supplemental property particles for achieving user-desired conflicting performance in the thermal and aesthetic aspects. In this study, the double-layered coating model has been firstly constructed using a ray-tracing technique. Then, 24 double-layered coating samples are prepared to extensively validate the constructed model. Using the validated model, the thermal and aesthetic performance of two double-layered coatings have been investigated under different total mass and particle mass ratios. The performance characteristics of the double-layered coatings have also been comparatively analyzed. For the easy applications of the double-layered coatings, the investigated performance is summarized and visually presented, as the first time, in two thermal-aesthetic charts. Without repeating the time-consuming numerical and experimental studies, users can easily apply the charts for optimal coating designs to achieve those conflicting performance requirements.