Influence of thermochromic coatings on the thermal performance of the multi-layer wall by numerical simulation

Abstract

Abstract The conventional coating cannot always play better performance due to the seasonal change in a year, especially in the hot-summer and cold-winter zones. To overcome this drawback, the thermochromic coating was proposed, and its color varied with its temperature and featured different solar radiation absorption. To explore the application feasibility of thermochromic coating on exterior multi-layer walls, a numerical model was developed for an exterior insulation wall covered with thermochromic coatings, while the influence of the thermochromic coating was analyzed on the thermal performance of exterior walls by a reference of conventional coating. Numerical results showed that different from the conventional coating, the thermochromic coating showed low absorptivity in summer and high absorptivity in winter. Compared to conventional coating, the peak temperature in outer surface could be reduced by 11.2°C–16.7°C in summer and increased by 7.8°C–10.2°C in winter, while the peak heat flows in the outer surface were reduced by 22.4–38.9 W/m2 in summer and increased by 21.3–26.7 W/m2. It showed the thermochromic coating had the interesting capability to dampen the heat gains in summer, while promoting the heat gain in winter. Employing thermochromic coating reduced the cooling load by 24.28% and the heating load by 21.36%.