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 Manhattan, it's had opportunities to engage in some high profile energy efficiency retrofits of their existing buildings. But it wasn't until they decided to build Four Times Square, a $500 million (USD), 48-story skyscraper on 42nd St. and Broadway that they had the chance to design a major building from the ground up with energy efficiency in mind. Fox & Fowle Architects, which designed the 1.6 million square foot speculative skyscraper for the Durst Organization, incorporated a variety of energy saving features into the building, including high visible light transmittance glass, natural gas-fired CFC-free absorption chillers/heaters, on-site fuel cells, and high efficiency lighting. Four Times Square has been called the first "green" skyscraper in New York City, and was the first major construction in downtime Manhattan in more than a decade. The Durst Organization has leased almost 100% of the building's floor space, including 82% to the Condé Nast publishing company and to the Skadden Arps law firm, proving that large, energy efficient structures can attract leasers and be profitable. Thanks to the energy conserving features built into Four Times Square, energy costs are expected to be between 10 and 15% lower than costs would be in a comparable building constructed with conventional technologies.

Technical Data

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.

Energy Data

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.

Economic Data

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.

Contacts:

The Durst Organization Douglas Durst 1155 Avenue of the Americas New York, NY 10036 212-789-1155 212-789-1198 (Fax) http://www.durst.org	New York Energy Research and Development Authority Robert M. Carver Corporate Plaza West 286 Washington Ave. Albany, NY 12203-6399 518-862-1090 x3257 518-862-1091 (Fax) http://www.nyserda.org
Cook + Fox Architects Robert Fox 30 Cooper Square New York, NY 10003 212-477-0287 212-477-4521 (Fax) http://www.cookplusfox.com	Tishman Construction Corporation Dan Tishman 666 Fifth Ave. New York, NY 10103 212-399-3600 212-489-9694 (Fax)

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