Optimal control parameter for electrochromic glazing operation in commercial buildings under different climatic conditions

Electrochromic glazing can dynamically control solar heat gains of windows depending on the indoor and outdoor environments. This means that the energy performance of buildings with the electrochromic glazing window systems are affected by control parameters and climatic conditions. This study proposes an optimized electrochromic glazing control parameter and value to improve the energy performance and sustainability of medium-sized commercial building in different climates. It characterized the annual heating and cooling energy consumption of a typical building model with the window systems for different potential control parameters, such as outdoor air temperature, room air temperature, solar radiation incident on the window, and global horizontal solar irradiance. A pattern search algorithm was applied to derive the optimal control value of each parameter for four window orientations in six different climatic conditions. Our results show that for the electrochromic glazing window operation, outdoor air temperature is the most effective control parameter for reducing both cooling and heating energies in all window orientations and climatic conditions. When the electrochromic glazing window on three sides of building is controlled at the optimal outdoor air temperature, the cooling coil size of the air handling unit decreased by 16.5% on average under different climatic conditions. Furthermore, the daily peak cooling loads reduced by an average of 11.8%. The annual heating and cooling energy consumption decreased by 46.1 kWh (17.4%) on average per unit window area compared with the typical static window case under six different locations.