Fuzzy logic model to classify effectiveness of daylighting in an office with a movable blind system

• A fuzzy model is proposed to estimate daylight illuminance and uniformity.
• Uniformity classes offered for the effectiveness of a movable blind system.
• Measurements were carried out to validate and apply a simulation model.
• The slat angles of 30° and 45° provided more uniformly distributed daylight.
• Fuzzy model estimated illuminance with a prediction power of 87%.

This study estimated daylight illuminance and classified its effectiveness in an office with a movable blind system. First, measurements were carried out to validate and apply a simulation model using DIALux. Second, the simulation model was constructed utilizing physical properties similar to those of the case office. Third, the simulation model provided the daylighting calculations in terms of the slat angles of the movable blind system. A fuzzy model was later employed using the Mamdani fuzzy inference system. Four inputs, namely, hour, angle, distance and location, were fuzzified in this model. The daylight illuminance at specific points was successfully estimated by implementing fuzzy rules, resulting in a prediction power of 87%. To test the distribution of daylight illuminance inside the office, effectiveness classes of uniformity were constructed by this model in accordance with daylighting standards and design norms. Regarding the movable blind system, slat angles of 30° and 45° provided more uniformly distributed daylight than other angles throughout standard working hours. Thus, according to the degree of match between the simulated and fuzzy models, the majority of the uniformity outcomes of the fuzzy model fully fit the simulation outcomes. Because the fuzzy model successfully estimated the daylight illuminance and its distribution (uniformity), it could be easily employed to examine early architectural design schemes.