Green architecture – Bill & Melinda Gates Foundation campus
Completed in the spring of 2011, the Bill & Melinda Gates Foundation campus is located in downtown Seattle across the street from the Space Needle. It has been recently awarded with LEED-NC (Leadership in Energy and Environmental Design for New Construction) Platinum certification – making it the largest, non-profit LEED-NC Platinum building in the world.
Designed by NBBJ, the 59,445 square meters (639,860 square feet) building replaces an asphalt parking lot with a campus that returns more than 40 percent of the site back to green space through two-acres of living roofs and native plantings. The campus also includes a variety of energy efficiency strategies, such as a roof-mounted solar energy system which provides energy for more than a third of the hot water use.
“The project started seven years ago with the initial target of LEED Silver, in support of the City of Seattle’s green building mandate”, said Margaret Montgomery, principal and lead sustainable designer at NBBJ. “Our main goal was to design the right building for the foundation staff and surrounding community. It just so happened that the best solutions were also the greenest.”
Highly engineered windows conserve energy while letting in exceptional daylight and views. Energy-efficient systems reduce the load on regional power supplies. Electric lights automatically dim in natural light and inactive spaces, thus saving energy in the Bill & Melinda Gates Foundation campus.
Water conservation was a big goal for the project to protect the local watershed from further depletion and pollution. It is expected that 4.54 million liters (1.2 million gallons) of rainwater will be recycled annually, and a 3.785 million-liter (one-million-gallon) rainwater storage tank underneath the campus is the primary water saving strategy.
The two-acres of living roofs with native and non-invasive drought-tolerant plants and trees absorb a significant amount of the rainwater runoff and the remaining roof and landscape runoff is collected in the rainwater storage tank, cleaned of pollutants and filtered back into the campus for reflecting pools, irrigation and toilets. These systems combined with efficient plumbing fixtures reduced the campus’ potable water use by nearly 80 percent and eliminated all polluted rainwater runoff.
Below the surface is a 2,839,000-liters (750,000 gallon) water storage system used as a thermal storage system that minimizes energy used to cool buildings by chilling stored water at night for recirculation during the day. Under-floor air ventilation saves energy and simplifies future space modifications.
The overall energy use has been reduced by nearly 40 percent and the upfront investment the foundation made in a 100-year, energy-efficient building will pay for itself in less than 30 years.
“By focusing on what was best for the overall project, we were able to reap benefits far beyond initial project goals. For example, we demonstrated it is possible to recycle construction debris at a rate of 97 percent – double the national average. In addition, over 20 percent of the project was built with recycled content and regional materials, resulting in boosting the local economy for 21 subcontractors that extracted and manufactured materials within 500 miles of the jobsite”, said Yancy Wright, sustainability director at Sellen Construction Company who were the contractor on the project.