2014 IES Street and Area Lighting Conference
September 14-17, 2014 | Nashville, TN
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The Pride of Portland
When construction wraps in 2013, the renovated Edith Green Wendell Wyatt Federal Building will have all the earmarks of a high-performance building—from the shading devices on the exterior façade right down to the task/personal lighting at the desktop
n the space-age world of The Jetsons, ”integrated building design” allows citizens to zip from high-rise to high-rise using a freeway in the sky that links these structures.
To drill down on how much energy will truly be used, the project team adopted a buzzword metric that is starting to gain traction in the building industry. The Energy Use Index (EUI) is equal to kBtu/sqft/year (Figure 1). Petterson draws an analogy to miles per gallon in the auto industry “except that in the building industry, a lower number is better.” The EUI for the Wyatt Building should come in between 31 and 36.
Shading, daylighting and electric lighting design are major components of the energy-saving strategy for the 18-story, 512,400-sq ft tower.
Shading and Daylight. A study of the building envelope included a thermal analysis involving the percent of glazing and shading, and a daylight analysis that factored in shading from surrounding buildings; building-integrated shading; and interior light quality.
After review, a shading system of aluminum reeds for all 18 floors was specified for three of the four façades (Figure 2). On the west façade, vertical reeds will provide 50 percent shading. On the east and south, the reeds are both vertical and horizontal. There is no shading on the north façade. During a large block of time during the work day, no electric lighting is needed to light the daylight zone of the building (0-16 ft from the window).
Electric Lighting. Complementing the daylight is a watt-busting electric lighting system for the office space and lobby. Working with an LPD target of .5 watts per sqft, the project team analyzed the configuration of luminaires, potential light sources, ballasts and room reflectance. For the predominantly open-plan office layout—70 percent of the space is open office—a T8 linear fluorescent direct/indirect system using suspended luminaires in conjunction with task lighting was specified. While the suspended fixtures have already been ordered, the furniture integrated task lights are not yet finalized, although LEDs have been proposed. The lighting will deliver 30.2 fc at .46 watts per sqft and can dim to 25 fc.
In the lobby, recessed downlights were strictly prohibited by the architect for aesthetic reasons. Instead, “we have two types of lighting—wall lighting using linear fluorescents and uplighting using ceramic metal halide,” says Petterson. “Both are very energy efficient sources. I think the energy savings mostly will be from the reduced light levels due to the daylighting and due to the increased perceived brightness of rooms which have surfaces within the visual field illuminated.”
Shrinking the carbon footprint of the Wyatt building isn’t just an exercise in gadgetry and technology. It’s also about winning the hearts and minds—and changing the habits—of tenants. Petterson calls it “tenant engagement.” Some of the strategies to be put in place include the banning of personal appliances (no more hot plates at the workstation); lower light levels as a result of task lighting; and adjusted temperature settings. These tenant-centric measures and others could squeeze another 6 percent in energy savings out of the Wyatt Building. Model tenants for this model of the future.