Thermal comfort investigation of stratified indoor environment in displacement ventilation: Climate-adaptive building with smart windows

The impact of combination of a passive ventilation system and smart windows in a climate-adaptive building is studied. A 3D steady-state RANS CFD simulation with a SST k-omega turbulence model was used to evaluate the temperature distribution and age of air for two cases of heat source and smart windows and two ventilation openings. The model was first validated for the first case with full-scale experimental data. For window-to-wall-ratio (WWR) ranges of 20-40% and four different room outlet opening locations, the validated model was used to determine the thermal comfort metrics of the studied building with smart windows cases. The mixed-climate environmental conditions of Atlanta-GA was used for setting up the boundary conditions. The results of thermal comfort analysis showed WWR = 30% and 40% are preferred for all studied windows and smart windows with electrochromic glazing, respectively. It also showed that up to 50% temperature difference reduction between the floor and ceiling is achievable with electrochromic windows. Smart windows with/without electrochromic glazing reduced the maximum relative air temperature between the floor and ceiling by 87%/30% compared to regular windows. This paper provides a resource for designing climate-adaptive buildings, improving occupant thermal comfort in existing buildings, and enhancing building aesthetic view characteristics.