Thermally responsive coating on building heating and cooling energy efficiency and indoor comfort improvement

Optic-Variable Wall (OVW) using thermally responsive coating on the facades of high-rise residential buildings is assessed by dynamic simulation. Evaluation criteria are energy consumptions (heat flux) during heating and cooling seasons as well as human thermal comfort. For the latter, Discomfort Hours and Discomfort Degree Hours during intermediate seasons are assessed according to the reference comfort zone given by ASHARE adaptive model. Two different cities, Shanghai and Paris, are studied to comparatively assess the effect of using such a coating under the two distinct climates. Results confirm the significant energy saving potential in the order of 8% for actual-stage coating and as high as 15% for the ideal one. Thermal Discomfort Degree Hours as well as Discomfort Hours are also reduced thanks to the tuning effect of the coating. The potential use of the temperature sensitive coating at the south wall (or facing equator) has better effect than walls of other orientations. Compared with the cold climate in Paris, Shanghai has comparable heating and cooling demand and is more adapted to the future deployment of OVW: the same OVW is doubly tuned (17% v.s. 8%) in Shanghai than in Paris, contributing to HVAC saving and improved comfort.