At night, while demand in the building is low, the power will be used to make ice in 44 storage tanks in the basement of the building. During the day, this ice is allowed to melt and is used to cool the air of the building, drastically lowering its energy consumption during peak hours (Fig. 7.19).
Displacement ventilation is used through the facility to minimize the volume of air to be cooled. The air distribution is under the floor to eliminate ductwork and to bring air in a higher temperature and lower speed so the energy loss will be minimized and the entire height of the room does not need to be cooed by blowing the air down (Fig. 7.20).
One Bryant Park chose to tap into more daylight for workspaces, evident by its clear exterior. By using baked frit to reflect light outside of the main vision plane, each floor has floor-to-ceiling glass that allows light to penetrate deeper into spaces, minimizing the need of interior lighting and providing views of the city (Fig. 7.21).
The tower’s exterior curtain wall is made up of floor-to-ceiling, double-lite insulated units of low-iron glass. To help control heat gain and glare, the units include a low-e coating as well as a ceramic frit that covers 60 % of the glass where the curtain wall meets the floor and the ceiling. The pattern gradually decreases in density toward the vision portion of each panel. Nonmetallic spacers in the aluminum mullion system and
Fig. 7.19 Ice storage tank diagram, © M. Keramati
extra mineral wool insulation at the floor slabs help achieve a U value for the assembly of 0.38—a thermal resistance that is better than most glass towers built in New York City over the last decade, but still below prescriptive code requirements.
The glass panels used in the facade have a light dotted pattern printed on them, invisible to naked eye from a distance, which restricts the infra-red heat radiations of sun while allowing visible light to enter, thus cutting daytime lighting expenses. Further, the building is designed in such a manner that no dark corners are left in it (Fig. 7.22).