Visual Comfort Based Algorithmic Control for Roller Shade and Assessment of Potential Energy Savings

Offices which are mostly operated during day-lit hours are fascinated toward incorporation of solar daylighting systems so as to get benefitted of energy savings along with intangible benefits like good health, well-being, and productivity of their occupants. But discomfort glare is usually ignored in front of rigorous energy load optimization practices and researches, or even if considered, is not properly quantified, which leads to a false evaluation of the performance of daylighting in the context of lighting energy savings. Blinds when operated with optimum visual comfort prevention measures, then only can create a functional day-lit environment. The present study includes modeling and analysis of an east facing office building located in New Delhi, India. It utilizes drafting tool Rhinoceros 3D 5.0 and simulation tool DIVA 4.0 to mathematically analyze the utilization of natural lighting for the office. The analysis includes properly arranged viewpoints similar to that experienced by any occupant, being placed in simulation environment so as to visualize and evaluate realistic glare scenario. The study further deals with the observation and analysis of the illuminance patterns inside the test space and glare values for different blind positions modeled. An algorithm has been developed to analyze the required visual comfort level of the space and suggests an appropriate blind position for every occupancy hour that eventually leads to estimate the potential energy savings through the utilization of daylight. It was observed that even after providing visual comfort to the occupants, the reduction in savings was marginal, measured to be 1% as compared to the case when visual discomfort is overlooked in daylighting utilization.