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Created on a moderate budget (about $220 per square foot, or $2,400 per square meter), the project achieved LEED Gold certification. The complex's three buildings are located at the north, east, and west edges of the site to maximize the space for a half-acre (0.2-hectare) courtyard of native grasses.

The orientation also provides protection from prevailing winds, and maximizes passive solar capability to harness warmth in winter and provide shade from summer sun, aided by adjustable louvers on the south-facing curtain wall.

The headquarters were designed to use 45 percent less energy for heating and air conditioning than codes stipulate, and 32 percent less total energy than a typical office building. The project previously received a 2009 AIA Honor Award for interiors.

Energy-Saving Utility

Maple Grove, Minnesota-based Great River Energy, a not-for-profit electric utility cooperative, sought a new headquarters that would model energy-efficient design for emulation by electric coop members across the state. The company succeeded with a building by Perkins + Will that earned LEED Platinum certification.

The 166,000-square-foot (15,400-square-meter) building achieves an estimated 47.5 percent energy cost savings compared to ASHRAE Standard 90.1-2004. The project combines underfloor displacement ventilation with a water-source heat pump and a heat recovery system to bring ultra-efficient heating and cooling.

The four-story structure has glass curtain walls over a concrete frame. To limit occupant discomfort near building perimeters due to summer heat gain and winter heat loss in Minnesota's extreme climate, the architects located circulation near the perimeter, with all occupied workspaces concentrated inboard, daylit by a series of narrow atria.

The building gets approximately ten percent of its power from wind and three to five percent from photovoltaic panels. This combination of energy efficiency and onsite renewable energy reduces the facility's fossil fuel use by 75 percent and cuts carbon dioxide emissions by 60 percent, meeting the 2015 goals of the 2030 Challenge.

Educational Exemplar

The Chartwell School for children with language-related learning difficulties, located in Seaside, California, achieves net-zero electricity use, aided by photovoltaic panels. EHDD Architecture's sustainable design strategies, executed on a relatively modest budget, earned the building a LEED-NC Platinum rating,

A premium was placed on daylighting, achieved with the help of tall, north-facing windows and clerestories, along with skylights. All teaching spaces are lit naturally during daytime hours, and photo-sensors help reduce the use of electric lighting.

The building is naturally ventilated, primarily through operable windows, and cooling was avoided completely, further contributing to a reduction in energy use of 57 percent below California Title 24 energy strictures. Radiant heating eliminates the need for air ducts, reduces the size of mechanical equipment, and helps keep the learning environment quieter.

The classrooms were kept to a small 650 square feet (60 square meters) — fitting for the school's small class sizes of eight to ten students. But to ensure flexibility of the building for future uses, classrooms are organized in pairs separated by nonstructural partitions.

To make sustainable design a visible part of the students' education, a 9,000-gallon (34,000-liter) cistern stores rooftop rainwater runoff, which is used for flushing toilets. The outfall from the cistern waters the science garden, where students grow organic food. Rainwater otherwise infiltrates on site.

Seaside Sustainability

The Charles Hostler Student Center provides sports facilities, an auditorium, an amphitheater, and gathering spaces for students and faculty on the campus of the American University of Beirut in Lebanon. VJAA tailored the facility to the Mediterranean climate, working with associate architect Samir Khairallah & Partners.

The 204,000-square-foot (19,000-square-meter) center consists of multiple building volumes connected by gardens oriented toward the sea. Solar studies informed building massing, orientation, shading, and internal daylighting strategies.

The project uses seawater cooling from below the site, with a low-energy absorption chiller that runs off a heat source, requiring only a small amount of electricity to run pumps. So, instead of adding huge chiller equipment to the electrical grid, the facility either recovers some waste heat from its own power generation, or produces steam with boilers. This system allows the center to provide chilled water and cooling for the lower campus.

In addition to emphasizing air movement, the design incorporates radiant cooling for areas of the buildings where larger gatherings occur regularly, such as the gym, pool, theater, and cafe. Solar panels heat water for the pool and for other uses.

The Hostler Center uses excess steam produced by the university to provide what little additional heating is needed in the warm Lebanese climate. The additional air system provides dehumidified, fresh air. Compared to an all-air system, this system reduces consumption significantly.

The project previously received a 2009 AIA Honor Award for architecture.

The 2009 jury for the AIA/COTE Top Ten Green Projects included Michelle Addington, Yale School of Architecture; Brandy Brooks, Assoc. AIA, Community Design Resource Center of Boston; William Leddy, FAIA, Leddy Maytum Stacy Architects; Nadav Malin, BuildingGreen LLC; Kim Shinn, LEED AP, TLC Engineering for Architecture; and James Timberlake, FAIA, KieranTimberlake.   >>>

Brian Libby is a Portland, Oregon-based freelance writer who has also published in Metropolis, Architectural Record, The Christian Science Monitor, and The New York Times.   More by Brian Libby

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SUBSCRIPTION SAMPLE A rooftop photovoltaic array crowns the LEED Gold-certified Gish Apartments, designed by OJK Architecture and Planning. Photo: Bernard André Photography Extra Large Image The community room at the Gish Family Apartments. Photo: Bernard André Photography Extra Large Image SUBSCRIPTION SAMPLE Nearly 200 people work in the LEED Gold-certified World Headquarters for the International Fund for Animal Welfare (IFAW) in Yarmouthport, Massachusetts. Photo: Peter Vanderwarker Extra Large Image Glazed circulation spaces look into a central courtyard at the IFAW headquarters. Photo: Peter Vanderwarker Extra Large Image The IFAW headquarters complex was designed by designLAB architects. Photo: Peter Vanderwarker Extra Large Image Located in Maple Grove, Minnesota, the Great River Energy headquarters building is LEED Platinum-rated. Photo: Lucie Marusin Extra Large Image Ample daylighting and a continuous dimming electric light system balance ensure energy-efficient lighting in the Great River Energy headquarters. Photo: Lucie Marusin Extra Large Image Perkins + Will designed the Great River Energy headquarters around a central atrium. Photo: Lucie Marusin Extra Large Image SUBSCRIPTION SAMPLE Chartwell School in Seaside, California, was designed by EHDD Architecture. Photo: Michael David Rose Reclaimed wood was used extensively in the LEED Platinum-certified Chartwell School. Photo: Michael David Rose Extra Large Image   Click on thumbnail images to view full-size pictures.