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New York Building Takes ‘Green’ Approach

Pictured is the Four Times Square Building, which has become a model for green building design because of its energy efficient heating and cooling system.

The Four Times Building in New York City was completed in 2000, and is still peaking interest because of its “green” features. The building, which stands at the northeast corner of 42nd Street and Broadway on the south end of Times Square, is 52 stories in height and includes 1.6 million square feet of available rental space.

The Durst Organization operates the building and rents the space. According to the Durst Organization, the green design elements make the building an appealing place to rent as well as a financially sound investment. As an example, they cite the energy efficiency of the building shell. Through the use of low-e glazing, the admission of daylight for task lighting is optimized, while the passage of heat is significantly reduced; thus building cooing costs are lower and comfort levels are higher.

Another major step in reducing electrical usage was the selection of gas-fired absorption chillers as the primary building cooling units. The design called for the chillers to be located in a large, high-bay mechanical room neat the top of the building. The location high in the building reduced the amount of otherwise rentable space needed for exhaust piping and puts the chillers in proximity to the rooftop cooling tower, thus reducing piping and pumping costs.

The units selected were six Trane Horizon™ two-stage direct-fired absorption chillers, rated at 620 tons each for a total of 3,720 tons.

The Horizon chillers are modular in design, and readily separable into three individual components. This simplified the installation of the units in the penthouse mechanical room. All of the components were lifted into position from street level by crane while the building was under construction in 1998.

The Four Times Square Building is equipped with six Trane Horizon absorption chillers rated at 640 tons each.

The Horizon units operate delivering chilled water at 44 degrees F with a 58 degrees F return. The equipment is designed for tower water temperatures of 95 degrees F and 85 degrees F returning to the chillers. The units are also used in the heating mode to provide hot water. Each of the units has the Trane UCP2™ control panel, which interfaces with a Siemens chiller plant management package. Chilled water from the Horizon chillers goes via variable speed pumps to two custom air handler units on each floor of the building. Conditioned air is distributed throughout the floor via VAV terminal units.

Finally, the building also features two 200 kW fuel cells, which provide electric power to the building grid around the clock.

“This was a complex project, and some of the ‘green’ features had never been used on such a large scale, so we had some adjustments to make,” said property manager Jim West. “But we’re definitely pleased with the results, and our occupancy levels suggest that we’re providing an atmosphere that tenants appreciate. We have inquiries and visitors from around the world to see what a high-performance building is all about.”

Publication date: 07/28/2003

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