Lighting Up Savings At Empire State Building
In New York City, the Empire State Building’s (ESB) energy and sustainability program is a forward thinking approach to commercial office building renovation. In broad terms, the goal is to reduce energy use in the ESB by 38% and to reduce costs by $4.4 million per year. To achieve this goal, ESB ownership has been working with the Clinton Climate Initiative, Johnson Controls, Jones Lang LaSalle, and the Rocky Mountain Institute to define the right steps in the right order—reduce loads; use efficient technologies; and provide energy saving control.
Starting with the building core, engineers first worked to control building loads by eliminating potential for wasted energy. Every window was refurbished, radiative barriers were added to the exterior walls, and a more efficient lighting design was adopted to reduce lighting power density. An integrated lighting control solution comprised of wireless lighting controls, wireless daylight and occupancy sensors, and digitally addressable dimming ballasts was chosen, and this is expected to reduce lighting electricity use in the pre-built tenant spaces by up to 65%.
To learn more about the lighting systems installed as part of the ESB energy retrofit, TFM recently posed several questions to Tom Myers, director of commercial real estate solutions at Lutron Electronics. Headquartered in Coopersburg, PA, Lutron is a designer and manufacturer of lighting controls and provided the lighting equipment for the pre-built tenant spaces in the ESB.
Q: While every facility’s lighting project presents different needs and characteristics, what would you recommend to facility managers (fms) who are evaluating lighting controls for their buildings? What kinds of energy savings can be realized?
For its project, ESB ownership worked with contractors and energy consultants to define strategies that would make the greatest contribution to energy savings in the pre-built tenant spaces. By focusing on occupancy/vacancy sensing, personal control, and daylight harvesting, the system that was installed is projected to deliver maximum savings while achieving a payback of less than three years.
For example, because the pre-built spaces feature significant access to outside light, daylight harvesting is used to ensure that electric light is supplemental, rather than the main source, in perimeter spaces. In the areas where daylight harvesting is applied, ESB estimates lighting energy savings of between 40% and 60%.
Q: Please describe the evaluation process for lighting controls ultimately chosen for the ESB retrofit. What issues were important to the facility management group there? How do the solutions that were installed address those issues?
• Enhance lighting performance while reducing renovation costs. Budgets had to be respected without sacrificing lighting performance.
Once these goals were defined, a lighting control evaluation evolved. Initially, ESB reduced its designed light power density by 30% (from the desired one watt/square foot to 0.7 watts/square foot) by using T5HO lamps versus T8 lamps and incorporating LED fixtures into entrance areas. Occupancy or vacancy sensors were then employed to minimize the amount of time that lights were on when the space was vacant. To reduce the applied lighting power by another 50% (from 0.7 watts/square foot to 0.35 watts/square foot), daylight harvesting controls were also adopted in the pre-built spaces.
By investigating wireless control strategies, they were able to achieve lighting power density goals and reduce the cost of labor. The firm managing the building, Jones Lang LaSalle, took the time to work with the project contractors to make them familiar with wireless technologies. They also kept an eye on future codes and regulations so the building would exceed current ASHRAE standards.
Q: What is the extent of the lighting controls at the ESB today? What types of lamps were used in the building? Do the lighting controls work with other building systems?
On a typical pre-built tenant floor, there are 50 wireless wall switches, 75 wireless occupancy/vacancy sensors, 15 daylight sensors, and 200 new light fixtures that are a combination of energy efficient fluorescents and LEDs. The controls contribute up to 65% lighting energy savings toward the ESB’s goal of 38% total building energy reduction.
Q. What is the expected payback period for this lighting controls installation? How can fms in other facilities calculate this payback period when considering a lighting control retrofit?
Product life cycle costs and how quickly and easily the lighting system can be reconfigured, expanded, and upgraded are also important considerations when determining return on investment.
Q. How much maintenance will these lighting systems require from the facilities management team at ESB?
Q. Are there additional measures the ESB might take in the future to keep its energy management systems ahead of the technology curve? What trends would you predict moving forward for fms who are working in existing buildings that are in need of energy retrofits?
Building codes and standards will continue to reflect more aggressive energy saving requirements, and ESB has chosen lighting control systems that are designed to exceed current building codes and set the standard for commercial building retrofits in the future. There are more than 81 billion square feet of existing office space in the world, much of which will need to be renovated, and fms can look to marquis projects, such as the ESB, for examples that are economically viable as well as environmentally sustainable.
A rapidly growing number of facility management (FM) professionals are using intelligent energy management (IEM) solutions to reduce their energy usage and costs. Not to be confused with a basic building management system (BMS), IEM tools help facility managers (fms) optimize their energy usage to analyze real-time and historical energy information. These tools build on traditional demand response solutions to provide a platform that enables fms to gain insight and control and integrate solutions within the expanding smart grid infrastructure.
Using that information, fms can then minimize energy consumption by intelligently controlling a myriad of devices and processes. Employing these capabilities can also help fms generate additional sources of revenue for their organizations.
There are many ways organizations can use IEM to reduce energy consumption and save energy costs. Ten of these strategies are listed here.
Reducing lighting costs. Lighting is vital for facility operations, and it can constitute a large portion of electricity costs. This is one reason BMS tools are so widely used. Whether a BMS is in place or not, IEM provides additional opportunities to reduce energy consumption. This might include controlling lighting as part of a demand response program or a natural lighting scheme.
Reducing HVAC costs. Large, central HVAC systems often have scores of major subsystems. It is common to have multiple chillers, multiple boilers, and one or more air handling units on each floor. IEM tools can calculate “thermal inertia” of buildings (or the rate a building heats up and cools down) and use it in combination with other real-time information to reduce the energy costs of HVAC operation.
Balancing electricity demand. Many organizations are now paying demand charges—an assessment for the peak electrical power a facility might require. Fms can use IEM to reduce their demand charges significantly by evenly balancing out their electricity demand over an extended time period (rather than incurring large peaks in demand).
Minimizing peak charges. For electric suppliers, the cost of delivering electricity varies with the demand. One way that electric suppliers look to link their costs to the prices they charge is through time-of-use (TOU) pricing or critical peak pricing (CPP). IEM can be used effectively with TOU or CPP programs to reduce electricity costs by automatically rescheduling or minimizing the operation of large, electricity consuming devices in a facility when on peak electricity prices are in effect.
Facilitating participation in capacity based demand response. When the weather is hot and humid, air conditioning usage causes the demand for electricity to increase dramatically. During these times, electric suppliers can issue a notice of a demand response event. Fms participating in a demand response program automatically take steps to reduce their electrical demand and are able to create an additional revenue stream through the compensation they receive for participating in the program.
Facilitating participation in economic based demand response programs. Economic based demand response programs have less to do with electric suppliers’ capacity to generate electricity and more to do with the cost of supplying it. Fms who reduce their facilities’ demand for electricity during times of high prices help electric suppliers save money. Electric suppliers, in return, compensate participating organizations for reducing their electricity usage at these times. IEM can help fms manage compliance and maximize the compensation received.
Verifying charge and payment. Automated billing systems are susceptible to programming and human errors. In addition, the charges for electricity usage, in particular, are becoming more complex. Without electricity (or other energy) usage details, fms have few ways to detect errors or contest charges on their bills. IEM simplifies verification of energy charges and eliminates the potential of overpayment.
Reducing human behavior and waste. Fms often use IEM to identify human behavior that unnecessarily increases energy consumption. For example, why does one process line consume 20% more energy on weekends compared to identical process lines? Is the weekend operator leaving equipment idling rather than shutting it down? With IEM, monitoring deviations from baseline or typical energy consumption patterns enables businesses to address such situations on an ongoing basis.
Identifying equipment failure. Just as IEM can help detect human behavior that increases energy costs, it can also identify trends in energy consumption that indicate potential equipment problems. For example, if electricity usage by one of several HVAC systems is seen to be slowly increasing month by month but another doesn’t display the same trend, it could be an indication that the HVAC needs to be checked.
Measuring energy saving efforts. Fms looking to reduce energy consumption and costs first have to identify where such opportunities exist. IEM solutions allow organizations to view their energy usage in multiple ways. For example, IEM solutions often display energy usage data organized in ways such as time of use (e.g., year, month, week, day), time intervals (e.g., minutes, hours, days), absolute or relative terms, and averages or trends.
Optimizing energy usage is an ongoing effort, but as the above examples show, IEM solutions provide a tool for fms to support energy management initiatives. In fact, when integrated with broader energy management and efficiency efforts, IEM solutions can help significantly reduce energy usage and costs while also generating new sources of revenue.
Hunt is senior vice president of Commercial and Industrial Sales for Comverge, a Norcross, GA-based provider of energy management solutions. He has worked in the energy industry for more than 29 years, during which time he has implemented numerous demand side strategies to optimize customer operations. Hunt is a graduate of Spring Garden College with a BS in Civil Engineering and continues training through corporate and industry professional training programs.