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About 65% of 1 Bryant Park's annual energy needs are generated on-site, thanks to a natural-gas powered cogeneration plant. The use of gas, the efficiency of the generator and the fact that the power does not have to be transmitted to the building across miles of cables means there's much less power wasted than in coventional skyscrapers.
"Up to two-thirds of all energy from power plants goes straight up the smokestack before even being converted to electricity," says Cook. "Another 8% is lost in transmission. The average efficiency for buildings this size thus winds up being about 27%. Ours is 77%."
There are a lot of other ways the tower keeps that number up. The basement of the building is equipped with 44 massive 1,000-gal. tanks filled with glycol and refrigeration coils. At night, when the pressure on the city's electricity grid is the lowest, the tanks freeze a collective 44,000 gallons of water which are used the next day to handle 25% of the air conditioning needs.
The 8,644 panes of glass that make up the building's 1.6 million sq. ft. skin are each dotted with a strip of ceramic frits at the top and bottom small white flecks that are spaced close together and then gradually become more diffuse, like the graduated sun shade across the top six or so inches of a car's windshield.
"To the eye, the window goes from about 70% opaque at the densest part of the frits to 0% opaque," says Cook. "But the sun sees the shading as completely opaque. That reduces the solar heat load." Further cutting the demand for juice is perimeter daylight dimming a sensor system that lowers the brightness of ceiling lights near the windows during the day and gradually raises it as the sun goes down.
The building goes easy on the water too. Catchment systems collect and save the 30 to 48 inches of rain that fall on the site each year. Across the building's two-acre lot that adds up to a maximum of 10 million gallons. This and other so-called graywater, such as waste from sinks and water fountains, is recirculated into the refrigeration system. Waterless urinals which rely on extra-slippery porcelain and a lighter-than-urine chemical reservoir in the drain where the liquid you don't want sinks into the liquid that you mind less saves an additional three million gallons a year. "That's about 2,920 miles of one-liter water bottles laid end to end," says Cook.
All this combined with the tower's airy, from-the-ridgetop views and its proximity to the greenery of Bryant Park across the street create the sense that the building is not just clean and cutting-edge, but downright virtuous. While Cook rightly touts the improbable closer-to-nature feeling this creates, he does concede that LEED designations even platinum ones can sometimes be misleading.
For one thing, designers hoping to boost their LEED score will sometimes concentrate on easy, marginal improvements that get their numbers up increasing by 50% the amount of building material they recycle during construction, for example rather than investing in costlier innovations that will pack a bigger environmental punch. "It's called 'chasing points,'" Cook says, "and architects are always on the lookout to see if other architects are doing it." No surprise, Cook insists there was no point-chasing going on in the design of this building.
Even if every LEED point is justly earned, however, the question isn't how the building performs the day you take the shrink wrap off, it's how it does 5 or 10 or 100 years down the line. And that can be harder to determine. Everything from fluctuating occupancy levels and breakdowns in equipment to tenants who ignore or disable green systems (covering up motion sensors that turn lights off in unoccupied offices, say) can drive performance way down. And since LEED ratings are granted a single time with no follow-up later, once platinum means always platinum, no matter how efficient the building actually is.
Still, if the BOA tower turns out to be nothing else, it's a proof-of-principle structure one that undeniably represents the state of the green art in 2010, even if that art turns out to need a lot of improvements down the line. If other architects chase the green standard to say nothing of the aesthetic, eye-candy standard that the new building has set, 1 Bryant Park will have more than done its work.