Biotech firm Genzyme built its main office in Cambridge, Massachusetts, in 2003 on an abandoned lot; according to Engineered Systems, the 12-story Genzyme Center features a number of sustainable features that helped slash the estimated energy cost for the structure by 42 percent. Much of the savings were a result of the building's central heating and cooling systems, which are powered by steam from a nearby power plant.

During the summer, the steam operates the absorption chillers, which contain a lithium bromide solution instead of hydro-fluorocarbon refrigerant. Warmth is provided by four heat exchangers, which rely on steam to provide hot water for the fancoil and air handling units. Meanwhile, a building automation system (BAS) from Tour Andover Controls oversees roughly 40,000 automation points across the building, with each point able to react to changes in climate. For example, if a window is opened, the BAS will instantly separate that area from the air conditioning system.

As for lighting, occupants have the ability to increase or decrease the brightness of the lights; the BAS eventually brings the lights back to their original settings to conserve energy, said Donna Thibodeau of Tour Andover. Meanwhile, BAS-controlled heliostats—large mirrors that follow the sun—that are mounted on the roof reflect daylight into the center of the building, which helps light an atrium, said Lou Cappozzi, supervisor of facilities engineering at the Genzyme Center. Other features of the building include a green roof, a curtain-wall glazing system that serves as a structural envelope, a 4-foot interstitial space for circulation and two rooftop solar panel arrays.      EC