Going beyond the code
The New York Times Building is a 52-story tower with 1.5 million gross sq ft and is a mix of both office and retail uses with open spaces and floor-to-ceiling glass walls.
It is important to note that the ASHRAE Standard 90.1 lists bare minimum requirements. Good design recommendations can go far above and beyond what is required. Such is the case with the New York Times Building, a 52-story tower with 1.5 million gross sq ft. The building is a mix of both office and retail uses with open spaces and floor-to-ceiling glass walls.
“We designed our building to use 1.28 W/sq-ft of lighting power. With [lighting controls], it’s only using 0.396 — that’s about 70% less,” said Glenn Hughes, director of construction for The New York Times Co.
The lighting controls use a number of different strategies to maximize occupant comfort and to provide flexibility and adaptability to the business owners. Strategies include daylight control, occupant control, target set point control (light level tuning), time clock control, and emergency lighting control. The centralized lighting controls equipment also has software to control, monitor, and report on the lighting usage in the building.
The daylight sensors maximize natural light pouring into a space by continually and imperceptibly adjusting the electric light levels to maintain a consistent overall light level as set for the people working in each space.
The lighting scheme for each floor is divided into zones, each with its own lighting levels that fit the needs of the employees (depending on what type of work they perform) and based on the amount of daylight that penetrates that space. More than 15,000 digitally addressable ballasts were used to achieve that kind of precision, said Hughes.
In addition to these savings, there is a derivative effect on the HVAC system energy performance. The dramatically reduced output levels of the lighting system means that less heat load is created by the lights, which means the air conditioning system works less, further reducing energy use in the building.
The story does not end by looking at energy savings alone. According to Hughes, lighting controls dramatically improved the lighting environment inside The New York Times Building. Employee comfort, increased productivity, flexibility of use, and reduced energy usage were all achieved by the lighting control system inside The New York Times Building.
Schultz is an electrical engineer with Metro CD Engineering and serves as education chairman for his local Illuminating Engineering Society section (IES). He is a 2011 Consulting-Specifying Engineer 40 Under 40 winner. Chow is the founder and owner of Metro CD Engineering. He is a 2009 Consulting-Specifying Engineer 40 Under 40 winner.