The invention, which relates to the field of smart windows, provides an energy-saving type intelligent external window optimization control method. An EC
casement window regulation strategy is determined according to different regions, different building types, and different orientations; the solar
radiant heat can be utilized effectively, the natural lighting is increased, and glaring is avoided;and the optimized control problem of the multiple control targets in a photo-thermal environment is solved and the
building energy consumption is reduced. According to the invention, on the basis ofarchitectural design parameters of the electrochromic
casement window, control logics of the electrochromic
casement window are set in an EnergyManagement
System module of the EnergyPlus; with Genoptsoftware, an outdoor horizontal illumination control threshold of a control parameter of the electrochromic casement window state in the established EnergyPlus
simulation model is optimized, so that the sum of the illumination
energy consumption and the
air conditioning energy consumption of the
building simulation is minimized. Therefore, the
building energy consumption is reduced effectively; and incorrect usage of the electrochromic casement window due to different regions, different orientations, different building types and different seasons is reduced effectively.