Balancing Visual Comfort and Energy Efficiency

With increasing interest in wellness and human-centric design in workplaces, the design of building enclosures is predicated on optimizing competing performance criteria, including visual comfort, thermal behavior, maintenance, and cost-effectiveness simultaneously. Managing this varied set of indicators, while integrating them into a cohesive design, is challenging on many fronts, particularly regarding the quantification of a design’s value proposition. Here, we present a case study for a large office building in South East Asia; a climate characterized by hot air-temperatures, high humidity, and intense solar radiation. The design of the building envelope takes inspiration from the vernacular architecture of local temples and shading elements while being charged with a performance-driven approach to minimize the impact of solar radiation and maximize visual comfort. Iterative design propositions were evaluated through the lenses of energy efficiency, daylight optimization, and visual quality to determine the optimal design approach, based on an exterior shading system of aluminum extrusions with a ribbon-window back-up wall. Our analysis indicates that the exterior shading system is able to reduce glare discomfort by 78%, increase time when interior blinds are raised, reduce overall energy consumption by 7%, require 5 fewer air handling units, and reduce the chiller capacity by 200 tons, resulting in a 300 ton reduction in CO2 emissions when compared to the same building without exterior shades. As a result, the simple payback of the exterior shading system is estimated at 12 years when productivity gains are factored in along with environmental benefits. Thereby, within the early design stages, the exterior shading strategy offered an opportunity to integrate a re-interpretation of local architecture with the environmental and financial performance for the design of a building enclosure that can address both energy efficiency and user experience.