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LD+A The Magazine of the Illuminating Engineering Society of North America

Sustainable Design  


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

BY PAUL TARRICONE

 

I 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.

Obviously, we’re not there yet; the Jetsons, after all, live in the year 2062.

In Portland, OR, however, Integrated Building Design Version 2011 is on display in the form of the Edith Green Wendell Wyatt Federal Building—a General Services Administration project funded by a Stimulus Package grant. This “shovel-ready project”—to use the vernacular of 2009—will be among the first generation of so-called high-performance green buildings when completed in 2013. On track for LEED Platinum status, the renovation comes with all the energy-related bells and whistles, such as site shading, building shading, daylighting, envelope load-reduction strategies and watt-squeezing electric lighting.

Architect Lisa Petterson of SERA, Portland (which led the A/E team along with Cutler Anderson Associates), described the design process last May at LIGHTFAIR in Philadelphia.

The Wyatt building upgrade, Petterson explained, is one small step in the effort to modernize the U.S.’s energy-hogging building inventory. Consider these statistics from the Energy Information Administration: Buildings use 38 percent of all energy in the U.S. and 20 percent of that amount goes toward lighting. Moreover, 72 percent of all electricity use is attributed to buildings, and 38 percent of that number is for lighting. With those figures in mind, the Wyatt building renovation was conceived as part of the “2030 Challenge,” which calls for a phased reduction in fossil fuel usage, culminating in carbon-neutral buildings by 2030. The Wyatt building is expected to yield an impressive 60-65 percent energy savings vs. a building designed to code, which translates to about a 57 percent fossil fuel reduction, putting it in line with the 2030 Challenge requirements for 2011-12.

Figure 1.

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.

TECHNIQUES

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.
Figure 2.

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.”

IDEAL TENANTS
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.

October 2011

 

 

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