commentWith a mission to "explore, explain, and protect the natural world," the California Academy of Sciences has a strong commitment to sustainability, but its day-to-day operation is very energy-intensive. To prove it is managing those loads efficiently, the academy decided to follow up on its original LEED Platinum certification by pursuing LEED for Existing Buildings Operations & Maintenance (LEED-EBOM). The early version of LEED under which it was certified excluded process loads—which make up the vast majority of the academy's energy—from the calculations. Process loads include electrical demand for equipment and activities that happen in a building, as opposed to the heating, cooling, and lighting needed to make the space functional. LEED-EBOM provides a more complete picture, so the second Platinum achievement makes a good case for the academy's commitment.
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Photo © Shunji Ishida
This multi-faceted institution sheltered by a undulating green roof takes a holistic approach to sustainable design
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KEY PARAMETERS
Location San Francisco
Gross area 400,000 ft2 (37,160 m2)
Cost $488 million
Completed September 2008
TEAM & SOURCES
Structural system Nucor Yamato Steel (With Over 95% Recycled Content)
Curtainwall Josef Gartner USA (Aluminum Extrusion 99% Recycled Content)
Concrete Webcor Builders (15% Fly Ash And 35% Slag Recycled Content)
The combination of radiant heating and cooling in the floors and natural ventilation has served the main public areas of the building very well, according to Ari Harding, director of building systems. Visual and thermal comfort in the building's internal courtyard, dubbed "the piazza," has been a challenge, however. "We have a constant tension between the needs of the [adjacent] aquarium, which wants a lot of light, and temperatures in the piazza," Harding reports. The piazza roof used to be sheltered by a fabric rainscreen, which has now been replaced with a low-profile, retractable, hard-shell roof. The academy divided the new roof so it can be deployed in sections, and replaced food service in the piazza with exhibits.
The exterior sunshades were originally controlled on a schedule, but that meant that on overcast days they were deployed with no sun in the sky, further darkening the interior. Harding's team was able to customize the Siemens Apogee building-automation system so it controls the shades based on signals from sun-tracking sensors on the roof.
Getting the living roof's plant species and watering right has taken some trial and error. "There was a myth going around that this roof would never have to be watered—that's fantasy land," says Harding. "We're in a space that's naturally desiccated in summer by constant wind and sunlight." The academy has no plans to stop pushing the technology envelope. The next major projects might include a cogeneration plant and a living machine for on-site wastewater treatment.
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