Multi-criteria evaluation of daylight control systems of office buildings considering daylighting, glare and energy consumption

Abstract

Through the coupling of glazing and shading systems, daylight control systems (DCSs) are formed. By using such systems, the visual comfort of occupants as well as the energy efficiency of the building can be greatly enhanced. Further, these systems are imperative in climates where excessive and uncontrolled daylight may result in significant increases in cooling loads and glare, as well as a decrease in visual efficiency. There is, however, an inherent contradiction in the design of DCSs. This is due to the way daylight affects indoor spaces in that, despite being beneficial for visual comfort, it can also be detrimental to energy efficiency and glare, or vice versa. Therefore, to achieve a near-optimal indoor environment, daylighting should be increased while glare and energy consumption should be reduced. In this study, 155 unique DCSs are evaluated in cardinal and intercardinal orientations using a multi-criteria decision-making (MCDM) method. For each design alternative, daylighting, glare, and energy simulations are conducted using UDI, sGA, and EUI as performance metrics. The MCDM method, then, ranks the utility of the DCSs by aggregating the weighted simulations results. Results indicate that the coupling of “reflected horizontal louvers” with “vacuum glazing” is the most frequently used best design alternative regardless of orientation. Further, it is revealed that among all the top-ranked DCSs in each orientation, those in the south orientation are found to be the most effective at improving daylighting, glare, and energy efficiency simultaneously. It is also found that when an architectural design is intended to achieve daylighting, glare reduction, and energy efficiency simultaneously, a south-facing building is the optimal choice.