An algorithm to represent occupant use of windows and fans including situation-specific motivations and constraints

A theoretical model of the interaction between a building and its occupants is developed based on field survey data; the role of the model in building performance simulation is illustrated. If free to do so, people adjust their clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. Initially responses to thermal conditions are considered. Trigger temperatures are established where responses to warm or cold thermal discomfort may occur. These trigger-temperatures depend on (among other things) clothing (which may depend on season and social conditions) and air movement (e. g., fan setting). Trigger-temperatures differ from person to person and from time to time. If several controls are available people will use those that are most user-friendly, effective and free from undesirable consequences, and this is represented in the model by a constraint assigned to each control option. The concept of constraints is then expanded to capture non-thermal stimuli for control use (e. g., fresh-air). Using datasets from surveys in Europe and Pakistan, estimates are made of the parameters used in the model: the comfort temperature in relation to the prevailing outdoor temperature, the extent of inter-personal variation of trigger temperature, the effect of a fan on the comfort temperature, and the values of constraints that affect the use of windows and fans in the surveyed buildings. The incorporation of the new model, including constraints, into building simulation code is illustrated. Some limitations or unknowns in the current model are identified and possible approaches for future research to fill these gaps suggested. The application of the model in building performance analysis and building design is discussed.