Pattern 14: Daylight from Top and Side

This pattern provides a model for effective daylighting design in small scale single story commercial construction. This building type constitutes the vast majority of new and existing buildings in North America. These buildings represent a tremendous daylighting opportunity through the use of skylights and vertical glazing which is applicable to retail, office, light industrial, and other small scale building typologies. This is, in part, because the entire floor plate, regardless of orientation or section depth has daylight access from overhead.
 
One of the perennial challenges in daylighting is providing an even distribution of diffuse daylight across the building section, especially at areas beyond the reach of perimeter glazing. This can be accomplished at very low glazing areas with the use of overhead skylights. Once an interior section depth exceeds 25’-0” the contrast between perimeter zone and core of the building begins to increase substantially during daylight hours. Since the human eye tends to adjust to the brightest location within a space this can cause the perception of darkness in the interior section, and glare due to the lack of luminous uniformity across the section. To address this condition, a second (or multiple) source of daylight can be added where possible to provide supplemental illumination and to wash key vertical surfaces with light.

In this case we explore a range of skylight distributions, transparent vs. diffusing skylight glazing, the inclusion of view windows, and the role of wall washing skylights. In all cases including skylights, the skylight to floor area ratio (SFAR) is 4%. For this simulation diffuse glazing is simulated at a 50% visible light transmission where clear glazing is simulated at 60%. As in most visual task areas, there are three primary goals for effective daylighting. The first is to control direct sunlight at visual task areas during all occupied hours. The second is to provide balanced luminance on interior surfaces, especially between the perimeter and key interior surfaces within the interior volume. The third is to provide sufficient ambient daylight illumination for visual tasks. The realization of substantial lighting power savings is only possible with the effective integration of the electric lighting systems and daylight responsive controls.

This case study example is the IDeAs Office Building in San Jose, CA, designed by the EHDD Architecture and Integrated Design Associates (IDeAs). The building is a renovation of an existing single story retail bank building. Through the use of daylighting, an innovative mechanical system, and rooftop photo-voltaic panels, the IDeAs office building achieves net zero energy use on an annual basis. The site receives predominately clear skies. The ambient illumination criterion is shown at 300 lux.