Day of the sun: Energy savings result from testing a mock-up of The New York Times’ new headquarters
Owners of The New York Times Co., along with researchers at the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratories in
“No prior studies looked in this detail at field performance in a facility of this size with as many hardware systems,” says Stephen Selkowitz, head of LBNL’s Building Technologies Department.
In March, the researchers provided Times’ owners with preliminary numbers showing significant energy savings. Typically, building owners find minimal energy savings from daylighting beyond a 10-15-foot deep perimeter, Selkowitz says. However, in the mock-up, the average daily lighting energy savings in the February-to-May test period ranged from 76 percent at 10 feet from the glass to 37 percent at 25 feet.
“Photo-cell-controlled dimmable lighting reduces electricity use in response to available daylight,” Selkowitz says. “Daylight levels are influenced by glazing and external shading, [and] dynamic operation of the motorized shades to control glare.
“Measurements reinforced direct observation that the quality of daylight in the space enhances the occupants’ experience,” Selkowitz says. The full range of answers, however, won’t be available until all the data is analyzed. Data collection ended in August.
The 51-story headquarters will feature an 800-foot curtain wall, a glass façade sheathed in sun-shielding ceramic rods and stairs linking 28 floors. The all-glass building, to be complete in mid-2006 at
The original tower design, with its exterior shading provided daylight, views and outdoor contact, but did not control glare and sun penetration, according to an LBNL report. The design also did not make provisions to dim electric lights to take advantage of daylighting, the report states. Consequently, the Times design team approached LBNL to assist in solving the challenge of integration and cost.
“The mock-up was built for four reasons,” says Glenn Hughes, director of construction at The New York Times. “First, we needed a furniture mock-up. Second, we realized there were not sufficient tools available to model natural light admittance, glare and daylight harvesting with certainty. Third, we wanted to perform analyses on some of our interior designs such as the communicating stairs. Fourth, we were able to take hundreds of our employees through the mock-up and gather many comments.”
It’s unusual for a building owner to invest this much time and money to get the technical details right, Selkowitz says. “It is also unusual for a research-and-development group and an owner to collaborate.”
A goal of the study is to change the paradigm for dimmable lighting controls in buildings, Selkowitz says. “Today, only about 2 percent of fixtures use dimmable ballasts. They are a low-volume, high-cost product [that is] difficult to integrate into a working system with sensors and controls. They are found in executive offices and a few daylighted spaces.
The project seeks to change that paradigm, to make dimming ballasts the standard choice, to allow light levels to be tuned to workers’ needs, to harvest daylight and to control emergency electric demand.
“This requires solving all the integration issues and convincing manufacturers that a market of enlightened owners will pay ‘reasonable’ premiums for a product that delivers the function,” Selkowitz says. “Our final goal is to get other large firms like the Times to ask for the same smart technologies.”
Times’ owners paid an undisclosed amount to construct the mock-up. The research was funded by a $250,000 grant from the New York State Energy Research Development Authority and $75,000 each from the U.S. Department of Energy and the California Energy Commission.
“The plan was to collect data over six months [winter solstice to summer solstice] that encompasses all the sun angles,” Selkowitz says.
Researchers installed more than 100 sensors to record lighting energy, shade height, interior illumination and luminance, sky conditions, and general lighting conditions using webcams. Limited occupancy surveys were also administered. The researchers used Radiance, a daylighting software, to develop detailed ray-tracing lighting simulation models to predict how the space will perform in different exposures and climates, and how daylight changes as shade fabric or fixtures change. They attempted to develop and validate procedures for the automated shading and dimmable lighting that provide visual comfort and enhance performance for occupants, while providing energy savings.
“The automated blind sensor location, calibration and operating logic are all critical, as are the sensor issues related to the dimmable lighting,” Selkowitz says. “The goal was to verify or improve performance [and] use the data gathered to write a performance specification.”
The specification was put out to bid this summer so that companies, including ones that did not participate in the tests, could respond. Times owners are currently reviewing the bids.
“A key goal of this project was to develop performance specifications, so that companies can more readily specify and procure these technology packages,” Selkowitz says. “At the same time, the manufacturers are being asked to rethink how they offer their products to owners in terms of procurement practices and pricing.”
“The New York Times has gained tremendous value from the experiment,” Hughes concludes. “The gift of natural light has been beautifully integrated with the interior architecture, creating a space that really feels good.”
The contract goes to …
Viracon of Owatonna, Minn., has been chosen as the supplier of glass for The New York Times’ headquarters; the glazing contractor is Benson Industries of Portland, Ore.
“The glass is a combination of Viracon’s VE-2M coating on low-iron glass, combined with a custom silk-screen pattern in a white ceramic frit,” says Christine Shaffer, marketing manager of Viracon. “The glass blends the aesthetics of a custom silk screen with solar controlling properties of the low-emissivity coating.
“The use of low-iron glass substrates continue to increase in popularity,” Shaffer adds “Low-iron glass is being used on the [
Stephen Selkowitz, Lawrence Berkeley National Laboratory, Building Technologies Department, Building 90-3111, 1 Cyclotron Road, Berkeley, Calif. 94720, SESelkowitz@lbl.gov
Glen Hughes, The New York Times,
Christine Shaffer, Viracon,