Quantifying the effect of irradiance-based blind control occupant behaviour models (BC-OBMs) on daylighting performance and energy consumption in office buildings

Blind use patterns significantly impact visual comfort and energy efficiency in office buildings. Accurately capturing this impact necessitates the integration of blind control occupant behaviour models (BC-OBMs) within building performance simulations (BPS) during the design process. However, incorporating BC-OBMs into BPS presents challenges related to transferability, predictive accuracy, and the complexity of adapting these models within simulation workflows, leading to discrepancies between predicted and actual building performance. This study quantitatively evaluates the impact of BC-OBMs on daylight and energy performance in a single- occupant office in Tiruchirappalli, India, by simulating fourteen existing irradiance-based BCOBMs, including two base case scenarios (blinds always open and always closed), and assessing the implications of excluding BC-OBMs from daylight simulations. Results reveal significant variability in daylight metrics and artificial lighting consumption when BC-OBMs are excluded from simulations, challenging traditional assumptions. Notably, seven models closely aligned with the baseline scenario of blinds always open, showing minimal impact on daylighting and artificial lighting predictions. However, certain models indicated a preference for closed blinds, suggesting a tendency among occupants to keep blinds closed, which contradicts existing assumptions about blind use in building codes. These findings emphasize the critical role of BCOBMs in improving simulation accuracy and bridging the energy performance gap. This study recommends integrating BC-OBMs into energy codes and green rating systems to enhance the reliability of daylighting and energy simulations.