An Energy Efficient Skyscraper: Four Times Square
The Durst Organization has long had an interest in
energy efficiency and energy conservation. As owners of some of the choicest
real estate in downtown
Window glass for the skyscraper is very high transmittance (.4 and .66) with a shade coefficient of .30. Heating and cooling technologies include extremely efficient natural gas-fired CFC-free absorption chiller/heaters. Two on-site fuel cells generate about 3 million kWh per year. Fuel cells are large natural gas batteries that generate clean power via a chemical reaction that produces water and CO2 as byproducts. Photovoltaic (PV) cells were used to a limited degree to generate electricity. PVs were integrated into the "spandels" on the building-the area of the façade between the top of one window and the bottom of another.
Windows were designed so that with high transmittance glass about 25% of a floor would receive daylight. The two on-site fuel cells generate about 3 million kWh per year. The PVs installed above and below the skyscraper's windows have a peak output of 15kW, enough to power five or six suburban homes.
An analysis provided by modeling simulation software, funded partially by a New York State Energy Research and Development Authority (NYSERDA) grant, estimated fuel savings. The energy efficiency features of Four Times Square are expected to reduce energy costs by 10-15%. Payback for the very high transmittance glass is about 14 months. Payback for the natural gas-fired CFC-free absorption chiller/heaters is approximately three years. Payback for the two on-site fuel cells could be less than ten years, depending upon the price of natural gas. Overall payback for the incremental costs in making the skyscraper energy efficient is expected to be between 6-10 years.
The Durst Organization
1155 Avenue of the
Robert M. Carver
Corporate Plaza West
Cook + Fox Architects
Tishman Construction Corporation