Smart window control device responsive to beam and diffuse solar radiation

A smart window control device comprising:

• a first sensor disposed on the exterior of one or more electrochromatic smart windows to measure an amount of direct solar radiation,
• a second sensor disposed on the exterior of the one or more electrochromatic smart windows to measure an amount of diffuse solar radiation,
• a controller having a processor with circuitry configured to:
• establish a representative model of one or more building zones based on occupancy, construction, lighting, or cooling properties of a building,
• implement a lighting control strategy for the one or more building zones based on the representative model or one or more user preferences input at a first user interface screen of an external device,
• control automatic operations of the one or more electrochromatic smart windows by varying, in discrete steps, a voltage applied to a stack of electrochromatic coating layers, or by modifying, in discrete steps, a fractional input power of an artificial lighting system, based on trigger points associated with the lighting control strategy and measures of the beam solar irradiation and the diffuse solar irradiation measured at the one or more electrochromatic smart windows by the first and second sensors, respectively, and
• determine with the circuitry a performance level of the lighting control strategy for the one or more building zones based on one or more predetermined financial metrics that include a comparison of total building energy consumption to a threshold,
• wherein the circuitry is further configured to determine a comfort score and an energy savings score indicating a relative importance of visual comfort and energy savings for the one or more building zones based on the representative model of the one or more building zones or the one or more user preferences,
• wherein the circuitry is further configured to implement a daylight control strategy as the lighting control strategy when the energy savings score is greater than an energy savings threshold or the comfort score is lower than a visual comfort threshold, and
• wherein the circuitry is further configured to implement a solar control strategy or a glare control strategy as the lighting control strategy when the energy savings score is less than or equal to an energy savings threshold and the comfort score is greater than or equal to a visual comfort threshold.