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Pelli's Platinum Visionaire Part of the trick is using spandrel panels that are insulated. Typical spandrel glass consists of two layers of glass (the inside pane is usually painted) with an air space between them — so they have the same R-value as window assemblies. The system employed on the Visionaire integrates three inches (7.6 centimeters) of mineral fiber insulation behind the interior layer of glass. The aluminum curtain-wall assembly also has thermal breaks to eliminate thermal bridging from the exterior to the interior structure. Building in Battery Park City Pelli Clarke Pelli has a history in Battery Park City, an artificial extension of southwest Manhattan made from the material excavated during the construction of the World Trade Center in the 1970s. Firm founder Cesar Pelli, an AIA Gold medalist, designed the seminal World Financial Center there in the 1980s. Now his son and partner Raphael Pelli is the principle designer for several projects in the area, including two other recent projects for the same developer, the Albanese Organization: The Solaire was the first residential tower in the United States to receive LEED Gold, in 2004, and in 2008 The Verdesian was the first to garner LEED Platinum. The Battery Park City Authority required that 40 to 60 percent of the exterior facade be masonry, so for the Visionaire the architects researched a range of brick and terra cotta options. "Because we wanted a material that would be carefully shop-fabricated and lightweight within the curtain-wall system, we developed a terra cotta rain screen with articulations scaled to the neighboring buildings' brick walls" Copeland says. "As a rain screen, no mortar would be required, saving money and time on both installation and long-term maintenance." Green Heights The Visionaire includes a number of carefully detailed roof terraces. Unlike on many high-rise buildings, the roofs are designed to be useful outdoor spaces, with views of the Hudson River and the Manhattan skyline. Battery Park City required 70 percent of the site area to be permeable surfaces, so both the occupied and unoccupied roof surfaces use green roof areas planted with sedums and a wide variety of taller grasses, shrubs, and small trees. The developers placed importance on the indoor air quality. The HVAC system is a four-pipe fan coil system. Fresh air is 100-percent filtered and preconditioned with balanced humidity control, and is supplied to every room in the units. The supply air is monitored and adjusted to maintain a comfortable humidity level. Using gas absorption chillers further reduces electrical loads. By keeping a constant exhaust from kitchens and bathrooms and adjusting for human comfort, the design team found that exhaust air could be reduced, as long as the carbon dioxide content was carefully monitored. Reducing the exhaust air can diminish the heat lost in the winter and gained in the summer. To further save energy, the air that is exhausted is sent to a heat exchanger to recover heat. The building also features an extensive wastewater reclamation system. All of the blackwater from the building is cleaned using a membrane filter, and the cleansed water is reused in the toilets, green roofs, and cooling towers for the building. Generating Energy The building is crowned with three rings of blue solar panels. The photovoltaics are integrated within the unitized curtain wall, which has mixed results: in the curved facade, some orientations are not optimal. While they do supply 45 kilowatts of renewable power to the building, the panels are partially aesthetic and symbolic. Another recent innovation incorporated into the building is a microturbine installed on the roof. This small generator uses natural gas to power a turbine — and works much like those used in jet aircraft. Recently turbines have been developed that are efficient in generating onsite electricity. "The 60-kilowatt microturbine is sized so that it meets part of the building's base electrical load. This way, the microturbine is operating 24-7 generating electricity," writes John An of Atelier Ten, environmental consultants on the project. "The waste heat is used to preheat the domestic hot water. The microturbine also helps to reduce the peak summer electrical load on the grid simply by generating some electricity onsite." >>> Discuss this article in the Architecture Forum...
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