Multi-objective optimization design of energy efficiency for office building window systems based on indoor thermal comfort

Different window design schemes have different effects on heating, cooling, lighting energy consumption and indoor thermal comfort. This research established four scenarios, considering different window design variables, such as: window to wall ratio, glazing type, overhang and fin depth, maximum and minimum outdoor temperature setpoint for window opening and window opening factor, to minimize different energy consumption and thermal discomfortable hours. Sensitivity analysis was carried out prior to optimization to compare the sensitivity of each window design variable to different research objectives. Through optimization based on the non-dominated sorting genetic algorithm II (NSGA-II), the recommended values of each window design variable were given, designers can choose different optimal schemes according to preferences. Results in this paper are of great significance in guiding designers in the early design stage of office buildings.