'A Very Brave Building'

-- Building Design & Construction, 8/14/2009 12:00:00 AM

Deeply inset windows (with PVs above them) offer energy savings at Judson University’s LEED Gold art, design, and architecture center.

Judson University, located along the Fox River in Elgin, Ill., 45 miles west of Chicago, is the only evangelical Christian university in the U.S. to offer a fully accredited professional architecture degree program, including the MArch degree.

To gain national recognition for its architecture program, the university held an international competition for the design of a new academic center to house its art, design, and architecture programs. The proposed Harm A. Weber Academic Center would combine classrooms, an art studio, a gallery, and a library in the greenest building possible within the $25 million budget—$8 million of which hinged on winning environmental grants.

The competition was won by C. Alan Short, RIBA, FRSA, a professor and head of the architecture department at Cambridge University. Short is known for his academic buildings—and for sustainable design, particularly in the use of natural ventilation. But he had never done such a building in the American Midwest.

Building Team members KJWW Engineering Consultants (SE/MEP), Rock Island, Ill., Burnidge Cassell Associates, Elgin (architect of record), and Shales McNutt (CM), Elgin, worked closely with Short & Associates in London to exceed the original goal (LEED Silver) and attain LEED Gold for the 88,000-sf facility.

The chief innovation of the Weber Academic Center is the use of natural ventilation. Built primarily of concrete, the building draws cool air at the base, circulates the air throughout the facility, and exhausts the warm air through roof terminals through a stack effect.

Although the Building Team hoped to use natural ventilation year-round, this proved impossible, given the wild temperature swings in the region. Instead, KJWW's mechanical engineers developed a hybrid “stack effect” approach that allowed the building to take advantage of local climate conditions. The building operates in “natural mode” during the spring and fall and milder days of winter and summer. The hybrid system's mechanical mode kicks in during times of extreme temperature.

Precast concrete was used in the floors, roof slabs, and walls for its thermal mass and to create a heat sink for the natural ventilation system. The exterior walls are built out four feet from the precast concrete walls. This air cavity provides the chase spaces for the vertical air flow in the natural ventilation system, and it also cuts much of the direct solar gain. Precast window units were inset in a “Swiss cheese” effect to reduce direct sunlight in summer.

The center runs solely on passive ventilation during 29% of occupied hours. The mechanical plant is needed only 48% of the time the building is occupied. As a result, Weber Academic Center's predicted annual HVAC energy cost is 43-47% less than the standard U.S. building.

The Building Team's hard work paid off in nearly $8.5 million in grants: $7.5 million from the 2004 Federal Energy and Water Appropriations Act, $200,000 from the Illinois Clean Energy Community Foundation, and $750,000 from the Kresge Foundation.

Building Teams Awards judge Anil Anuja, PE, RCDD, LEED AP, called the project “bold and very unique,” and jurist Carol Ross Barney, FAIA, deemed it “a very brave building.” —Robert Cassidy, Editor-in-Chief