February 1, 2010
Yale’s Kroon Hall is proof positive that aggressively green buildings—even carbon-neutral ones—don’t have to sacrifice beauty to achieve their environmental goals.
The student lounge in Kroon Hall is a vaulted, light-soaked loft facing east over a small weald to Yale University’s Gothic science halls beyond. Part of the new headquarters of the School of Forestry & Environmental Studies, the lounge blossoms from a central stairwell, its floor-to-ceiling oak panels interrupted only by windows—and windows, and more windows. On a recent visit, a few students huddled at the room’s edges, some glued to laptops, others chatting sotto voce, as the winter sun washed through the photovoltaic panels overlaying the skylights. The place is bright, lean, jaunty, and, on green technology, one step proudly ahead of everyone else. It is, in short, your classic Ivy League overachiever.
Kroon is Yale’s first aggressive foray into green architecture. At 58,000 square feet, it rises three stories over the spot where an early-20th-century power plant once wheezed and sputtered. It’s a proud showcase for the country’s oldest forestry school, which has claimed among its own overachievers the naturalist Aldo Leopold and the Conservation International cofounder Peter Seligmann. Important work happens here, and the building suggests as much. Through green technologies and the purchase of carbon credits, it has slashed its carbon footprint to zero. And through artful choreography of light, air, and materials, the building rebukes the notion that carbon-neutral interiors can’t be beautiful, too. “You can design a building that has all the bells and whistles of low-environmental impact, but it can still be an alien environment that’s disconnected from our affinity for natural systems,” says Stephen Kellert, the Yale professor who led the effort to build Kroon. “This building has a dialogue between inside and outside spaces.”
The designers’ approach to the $33.4 million project was to make a building that uses as little energy as possible. Everything else followed. Hopkins Architects, of London, working with the Connecticut firm Centerbrook Architects and Planners, conceived of a slender footprint. The 218-foot-long southern exposure draws in winter light, and the 54-foot-long eastern and western faces are veiled by red-cedar louvers that block the powerful summer sun. Rooftop PV panels convert power from DC to AC, which supplements power from Yale’s grid, and break up the sun streaming in through the skylights. “And the more the light bounces, the more even it is,” says Centerbrook’s Mark Simon, “and the more you have a sense of connection with the outside.”
Meticulously orchestrated heating and cooling gently circulate air around the building. A low-pressure ventilation system nudges air through plenums and diffusers in elevated floors, slashing the waste typical of places that blast air from overhead. Heat exchangers pull warmth from exhausted air
in winter and extract stale air that’s been water-cooled in summer, then return it to the interior. Geothermal wells 1,500 feet in the earth help heat or cool the building, depending on the season. Hallways have red and green semaphores that tell occupants when to open and close windows.
Materials are scrubbed clean of the fossil-fuel economy as much as possible. The concrete that insulates many of Kroon’s walls and ceilings has in its mix 10,000 pounds of blast slag, a postindustrial recycled material. The FSC seal consecrates 80 percent of the building’s wood, and there’s plenty of it. Half of the red-oak paneling comes from Yale’s own forest. The overall effect is one of abiding warmth. Rosalyn Cama, a Smart Environments judge, says, “It’s cocoonlike.”
The 2009 IIDA/Metropolis Smart Environments Awards winners:
THE PLANT CAFE ORGANIC
Zimmer Gunsul Frasca Architects
Hopkins Architects and Centerbrook Architects and Planners