Design of Metal-Dielectric Multilayer Coatings for Energy-Efficient Building Glazing

A systematic approach to the design of metal-dielectric multilayer coatings is proposed for energy-efficient building glazing application. Thirty-six coatings were modeled with alternating metal (Ag, Au, Cu) and dielectric (TiO2, Ta2O5, ITO, ZrO2, SiO2, Al2O3) thin films in three-layer (3L) and five-layer (5L) configurations. It is found that the optical performance is less affected by the bottom dielectric layer compared with the metal and middle/top dielectric layers. The 5L coatings offer a competitive modulation of optical properties, ensuring an optimal balance between luminous transmittance and infrared reflectance. 5L configuration ensures a higher visible transmittance in the whole visible region with peak values close to those of unfunctionalized glass (approximate to 85%), i.e., 3-4% higher compared with the 3L configuration. The optical properties of the optimized multilayers are then used as inputs to building energy models of typical office buildings located in extreme cold and hot weather conditions. The 5L-Ag configurations achieve significant reductions in cooling loads under hot climate conditions (around 15%) without compromising access to daylight (important driver of occupants' comfort and wellbeing). However, under cold climate conditions, cooling energy savings are outweighed by unintended increases in heating loads, confirming the need for more climate-driven glazing research efforts.