Balancing comfort: Occupants' control of window blinds in private offices

The goal of this study was to develop predictive models of window blind control that could be used as a function in energy simulation programs and provide the basis for the development of future automated shading systems. Toward this goal, a two-part study, consisting of a window blind usage survey and a field study, was conducted in Berkeley, California, USA, during a period spanning from the vernal equinox to winter solstice. A total of one hundred and thirteen office building occupants participated in the survey. Twenty-five occupants participated in the field study, in which measurements of physical environmental conditions were cross-linked to the participants' assessment of visual and thermal comfort sensations.; Results from the survey showed that the primary window blind closing reason was to reduce glare from sunlight and bright windows. For the field study, a total of thirteen predictive window blind control logistic models were derived using the Generalized Estimating Equations (GEE) technique.; As hypothesized, the probability of a window blind closing event increased as the magnitude of physical environmental and confounding factors increased. The main predictors were maximum window luminance, average window luminance, background luminance and vertical solar radiation at the window. The confounding factors included Mean Radiant Temperature (MRT), direct solar penetration, and participants' self-reported sensitivity to brightness. The results showed that the models correctly predict between 73--89% of the observed window blind control behavior.; The field study also examined a new method for assessing the visual comfort sensation from daylight using a digital luminance map. Sensation of discomfort glare from daylight was moderately correlated with simple luminance-based variables captured from the luminance maps, suggesting that these variables could be used as discomfort glare predictors as an alternative to the existing Daylight Glare Index.; This dissertation extends the knowledge of how and why building occupants manually control window blinds in private offices, and provides results that can be directly implemented in energy simulation programs. This study concludes that future work is needed to develop control algorithms that maintain satisfaction while allowing the energy-saving potential of automated shading systems to be fully realized.