Conventional wisdom holds that carefully designed exterior louver systems tuned to a building’s earth latitude and its glass wall’s compass orientations do a better job of regulating sunlight than interior louver systems due to the intuition-friendly observation that exterior systems reflect or shade the sunlight before it ever enters the building. A multi-criteria, multi-variable analysis performed on a 3600 SF multipurpose space came to different conclusions. The results showed that when accounting for such design criteria as carbon footprint, glare, optimal daylighting and solar heat gain of the interior, tuned exterior louvers perform well against some measures but fared poorly in others, making the decision between types of louver systems a matter of setting performance priorities and aesthetic preference in any given building. This paper summarizes a student’s independent research study in which she tested her studio project’s arrangement of sun louvers in a large multipurpose space, measuring a number of factors with a goal of determining the best design. Four interdisciplinary faculty collaboratively reviewed her research from architectural, structural, and environmental perspectives. For the analysis, Cove Tool, eQUEST, Tally, and EC3 software were used to test the performance of various louver layouts. A series of separate studies investigated whether the presence of louvers, their solar orientation, the location of the louvers relative to the glass wall, and louver spacing impacted daylighting and energy performance and carbon footprint reduction. All louver studies were compared to a reference design of exposed non-louvered glass, specified to meet minimum code standards. While some results followed widely accepted logic regarding the design of sun louvers, many differences in performance were either not as dramatic as expected, or positive performance results in one category were offset by negative performance results in another. In the end it is evident in this study that the detailed refinements of louver design do not dramatically affect daylight, energy, or carbon footprint performance in a way that would provide designers with clear performance directives, in the absence of preset priorities, so such factors as aesthetic intent may ultimately take on a decisive role.
Severson, Alexis; Mansy, Khaled; Spector, Tom; Phillips, John; and Homer, Jeanne
"Quantitative Assessment of Sun Louver Design Performance,"
Building Technology Educator's Society: Vol. 2021
, Article 10.
Available at: https://scholarworks.umass.edu/btes/vol2021/iss1/10