Follow the light
Our panel discusses the current state of lighting controls technology, codes and standards, and the benefits of energy-efficient lighting controls.
Our panel discusses the current state of lighting controls technology, codes and standards, and the benefits of energy-efficient lighting controls.
CSE: Beyond ASHRAE 90.1 and ICC's International Energy Conservation Code (IECC), what is driving the growth of lighting controls in the United States?
Craig DiLouie : The green building movement, emerging evidence linking personal lighting control and productivity, and energy conservation are driving growth of lighting controls in the United States. The green design movement, for example, has put daylighting back into construction's mainstream, resulting in new opportunities to save energy using daylighting control strategies.
Studies of personal lighting control indicate that workers are more satisfied when they can dim or otherwise control their own lighting conditions; meanwhile, the flexibility of controls can contribute strongly to workplace strategies such as hoteling and hot-desking. Finally, energy conservation is accelerating demand for lighting controls across the board. As an energy-intensive nation, we are constantly in need of new generating capacity, with the often cheaper alternative being to use less energy. Technology and energy codes have virtually squeezed all of the available wattage out of lamps and ballasts, which is why policy makers are increasingly turning to energy, not power density, as a key policy metric, and favoring controls in the latest codes.
Siva Haran : Energy Policy Act (EPACT) 2005 and other utility rebates provide incentives in terms of tax deductions or rebates to people who make investments in energy-efficient measures. These measures include lighting controls. Commissioning, load shedding, and energy monitoring are other areas where lighting controls will play a significant role in the near future. Results of lighting research show there is considerable improvement in productivity, performance, comfort, and well-being of human beings when they are provided with personal controls for lighting in the spaces. This increases the demand for personal controls. Dimming controls are growing because they increase the aesthetic appeal of a space. Also, with the advent of new technologies like LED and their ease of controllability, there is going to be big demand for lighting controls.
Rodrigo Manriquez : Beyond [U.S. Green Building Council] LEED, I believe that sustainability, in the general sense, is raising awareness of well-integrated design. The sequential days to designing a building are a thing of the past. Owners and tenants alike are driving a well-informed and keenly aware architect/client relationship that focuses on providing integrated solutions, regardless of someone's specific contribution to the design process. Controls are an important component.
James Wise : Of course, what I'd like to see more of is lighting controls used to enhance and enable users' experiences and performance within the building. I think there are great opportunities here, with everything ranging from increased safety to better wayfinding, using buildings as teaching tools, and emotional engagement with the building settings.
One safety lighting controls application that came out a couple decades ago was called “SALi” (Supplementary Areal Lighting). The idea was that people who parked their cars in an underground or building enclosed parking garage, which can be dangerous places, would go to their floor, punch in the number of the stall where their car was, and this would turn on much brighter overhead areal lights between where they were then and where their car is located. New lighting controls could make this work even better, because it could be largely automated with implanted RFID tags that users would take with them, which would turn on lighting and guide them to their vehicle.
“Let the building teach” is one of the goals of green buildings being promoted in arch schools these days. The idea is that just by visiting and using a building, people should learn something about the environment and how the building is working to save energy, or provide clean air.
I see lighting as being used as part of this educational message, perhaps illuminating system components when they activate at certain times, or indicating system states. I was in a building once where a series of lamps in a very aesthetic type of bar graph distribution lit up according to how much energy the solar cells on the roof were producing. Visitors could trace a history of solar power generation over the day.
CSE: How can controls help lighting designers and electrical engineers provide aesthetic lighting systems in an energy-efficient way?
Haran : Dimming light fixtures will shed energy load and at the same time increase the aesthetic appeal of a space. Architectural dimming, which controls light output down to 1%, is used in spaces where lighting is required for critical tasks for longer periods of time. Architectural dimming can also provide glare-free illumination with no distractions in spaces such as restaurants, theaters, or patient examination rooms.
General dimming (down to 10%) can be used in areas like large and small offices, corridors, and large public spaces for load shedding, and daylight harvesting. High-performance dimming (down to 5%) can be used in spaces used for smaller time durations like small meeting rooms and lobbies. With the advent of LED, color temperature of the lamps can be controlled providing different scenarios for different functions.
For example, a restaurant in Boston uses the same LED cove luminaires with 4100 K color temperature for breakfast settings and 3000 K color temperature for dinner settings, balancing the circadian rhythm of occupants.
Manriquez : As lighting designers, oftentimes we act as a liaison between architects and electrical engineers. Our ability to focus on the duality of our deliverables helps us reach solutions that are a direct response to a design concept in which controls allow us to organize scenes within the stage of architectural elements. The pragmatic response to the tenant's needs or programmatic criteria defines the efficiency of the control systems.
Wise : For one thing, controls enable lighting designers to get away from simplistic strategies when it comes to lighting buildings with aesthetic intent. Advanced lighting controls allow for more nuanced types of lighting strategies, which allow for more dynamic and focused kinds of aesthetic appeals.
I wrote an article about a children's hospital with a huge light wall on one side of a large atrium space. The pattern of lights on the wall and how they change is determined by the position and amount of children's activities in the space. Kids discover this very quickly, and have a great time running around, trying to get the lights to change to certain patterns or colors. The purpose of this whole light-activated display wall is simply to try and bring a joyful experience to what is otherwise a potentially depressing visit.
DiLouie : Lighting controls serve two purposes. First, they can satisfy visual needs by providing flexible lighting control over an individual's lighting or in a group space such as a group workspace or conference room. This enables the lighting to support changing workplace needs and individual preference and need. Second, lighting controls can support energy management goals by reducing either the amount of power the lighting system uses (e.g., dimming, automatic shutoff) or the amount of time the lighting system is being used (e.g., automatic shutoff). The beauty of using dimming as an energy management strategy is you can reduce the lighting load in a way that is imperceptible to most occupants, thereby preserving the integrity of operations and ability to enact strategies such as load shedding and daylighting control.
CSE: How are lighting controls impacting the performance of occupants, such as students, teachers, and office workers?
Wise: So far, from what I can see, they are expanding the possibility space of how people use buildings or get the building to better support activities within it.
For example, after my 30 years of college teaching, you cannot believe how difficult it still is to find a classroom that allows lighting to be adjusted so that the instructor can present in PowerPoint or overheads in lectures, and still have lights on for note taking or discussion. Also, modern instructional techniques will often have students work in ad hoc groups and then compare and present findings.
It would be nice to have classroom lighting that could be used to both segregate groups and highlight groups, but I have never seen this enabled, as I have in team spaces in the business world. I think that advanced lighting controls will allow users to better support a more diverse array of activities in ways that are much more satisfying for users, if they are done right.
DiLouie : Personal lighting control has been demonstrated, in research, to increase office workers' job and environmental satisfaction, while also generating significant energy savings. In visual needs applications, the flexibility of lighting controls can be very desirable. In most energy management applications, however, the goal of the lighting controls is not to enhance worker satisfaction, but instead to achieve the highest level of energy savings while being virtually imperceptible to or otherwise not irritating occupants.
One office-lighting field study, conducted by the Light Right Consortium in 2004, found that 91% of participants regarded direct/indirect lighting with wall-washing and individual fixture dimming control to be comfortable compared to 71% for recessed parabolic fixtures without individual control. The researchers concluded, “People with dimming control reported higher ratings of lighting quality, overall environmental satisfaction, and self-rated productivity… [and] showed more sustained motivation and improved performance on a measure of attention.” Another 2007 National Research Council Canada study found that personal dimming control produced 11% energy savings while contributing to a correlation between the presence of the controls and higher job and environmental satisfaction.
Manriquez : I am a bit challenged because I am a proponent of post-occupancy evaluations, yet I remain hopeful, that the prescriptive measures established within the verification credits set by LEED are the beginnings of a true understanding how our buildings are performing. I find all too often that much of the design intent, after occupancy, tends to be unsupervised and does not provide the level of sophistication conceptualized and implemented during the design phases. I believe a meaningful metric for occupant performance, beyond comfort, is yet to be developed.
Haran : Multiple studies have shown that classrooms with proper lighting—including ample natural daylight—have a positive effect on academic performance. With digital lighting control, the electric lights in a classroom are automatically dimmed and brightened in imperceptible increments in response to changing natural light levels in the room. Results indicate improvement in performance, attitude, and motivation.
Today's digital lighting control systems allow schools to effectively meet multiple needs by giving teachers and administrators flexibility and control over the lighting in every part of their facility, from the classrooms and cafeteria to the administrative offices, gymnasium, library, and hallways. Flexibility and control are not the only benefits. A digital lighting control system also offers energy code compliance, operating cost savings, optimized productivity, high teacher/student satisfaction, simplified maintenance, and efficient central management.
CSE: How are lighting controls impacting the health, comfort, or well-being of hospital patients or the elderly living in assisted-care housing?
Haran : Lighting control enhances the hospital experience for patients by giving them some control over their environment. They can dim the lights when they want to sleep, turn them up when they have visitors, and adjust them to a comfortable level for reading, watching TV, or resting. This creates a more soothing and homelike patient room, which decreases patient anxiety and increases patient satisfaction.
Wise : Lighting controls are enabling lighting strategies that can significantly improve functioning and quality of life for patients in healthcare settings, and residents of elder or assisted-care housing. For example, a novel night lighting system that illuminates the perimeter of a door frame has been shown to assist elderly residents' postural control, while assisting them to find a bathroom in the middle of the night. This type of assistive lighting can be controlled by sensed lighting levels in the resident's room.
Lighting can also assist synchronization of diurnal body rhythms by having residents experience higher lighting levels with a particular power spectrum at specific times of the day. Such synchronization helps residents both fall asleep easier and maintain sleep during the nighttime hours.
CSE: What are the most pressing integration issues that engineers are facing with regards to lighting and building automation systems?
DiLouie : There are three ways that lighting controls relate to building automation. First, lighting control systems can control HVAC, service water heater, and motor loads, basically functioning as a basic energy management system. Second, energy management systems (EMS) can control lighting directly. Third, an energy management system and a lighting control system may need some type of integration device to be interoperable. This brings up integration issues, either between an EMS and lighting controls, which may require a device such as a gateway, or between lighting controls and other systems such as security, audio-visual, and room partitions.
Haran : Incompatibility between the lighting control system and BAS is a major concern. They have to be truly compatible with the chosen automation protocol standard. One other area where benefits fall short of expectations is in the operation and maintenance of the system. In spite of advances in automation and integration, systems are not install-and-forget. They require operators to run them and maintenance personnel to keep them running. Systems will have to be periodically updated as new software is developed. Ignoring these costs, when considering system benefits, will result in overly optimistic benefit projections. Recent trends in energy codes encourage steps toward integration and may mandate integration in the interest of energy efficiency.
Manriquez : When we embark on understanding the criteria set for a project, we prioritize design vision and efficient solutions. The first item refers to identifying the characteristics of a space and its users. The second item refers to how the users perceive the space and personalize it. BAS are the backbone of linking the two items. As lighting designers, we gather preferences specific to a client and orchestrate how the solutions must be controlled, and aid the electrical specification in achieving it successfully.
CSE: How are energy codes and standards impacting lighting controls?
Haran : Watts-per-square-foot is the density of the rate of using energy. Our present codes actually limit connected load and do not take into account load shedding by bi-level controls, dimming, or occupancy sensing, nor for hours of use. The building industry is slowly moving toward Zero Net Energy or Carbon Neutrality, which is the goal of Architecture 2030 program. Toward this end, energy codes and standards, such as ASHRAE 90.1, are giving credits or mandating the use of lighting controls in the upcoming versions. There is a drive toward a new metric, watt-hours-per-square-foot, rather than watts-per-square-foot.
DiLouie : Energy codes have aggressively promoted adoption of automatic shutoff lighting controls, such as intelligent load-scheduling control panels and occupancy sensors. They are now beginning to promote other types of controls, such as daylighting controls.
Manriquez : Codes and standards shape the base layer of compliance. I think the true benefit is in assessing the potential of lighting controls as a critical component in maximizing energy performance and daylight integration.
Wise : The hassle over lighting power density in the revised Federal Energy Code is what prompted the lighting quality research project I managed back at Pacific Northwest National Laboratory in the early 1990s. There were serious questions then if lighting quality could be maintained at the low watts-per-square-foot levels being pushed by environmental organizations. Well, the answer was yes, but it requires some really unique lighting design. A study, sponsored by New York State Energy Research and Development Authority, showed how a demo heterogeneous lighting system with foolproof control interfaces could reduce classroom lighting power densities to an average 0.73 W/sq ft, which is 50% less than ASHRAE 90.1 2007/2010. I wish I had that type of lighting design in recent teaching experience, but looking at it makes me realize how poorly designed educational institution lighting systems truly are.
CSE: How are advances in LEDs and other luminaires impacting selection and specification of lighting controls?
DiLouie : Traditionally, lighting and controls were specified as separate items, but increasingly this barrier is being broken down due to the advantages of integrating control with the lighting upfront. One interesting development is the integration of lighting controls such as photocontrols and occupancy sensors. The device contains all of the controls necessary to enact daylighting control or automatic shutoff strategies. Examples include hi-bay fluorescent luminaires with integral sensors and direct/indirect luminaires commonly specified in offices and classrooms.
Haran : LEDs may offer potential benefits in terms of controlling light levels (dimming) and color appearance. However, not all LED devices are compatible with all dimmers, so manufacturer guidelines should be followed. As LED driver and control technology continues to evolve, this is expected to be an area of great innovation. Dimming, color control, and integration with occupancy and photoelectric controls offer potential for increased energy efficiency and user satisfaction.
Manriquez : LEDs are an evolving source that the industry gravitates toward due to its inherent first-look benefits, life, maintenance, and efficiency. In an industry that advances rapidly without checks and balances, there is a great disconnect between quality and availability. Controls are included in this spiral of options and customized to match a particular product. We practice caution in disseminating information and rely on proven control platforms that interface with LED sources.
CSE: The New York Times recently ran a story that the city's skyline is changing because more buildings are turning interior lights off at night and shifting to lighting crowns for distinction. Is this a good thing or a potentially negative outcome of energy and emissions conservation?
Manriquez : When lighting is used indiscriminately to accent a building, I think we have missed the point, and an opportunity to educate the client and the entire project team. Careful selection, design, and mounting of lighting equipment will yield energy efficiency, while offering great aesthetic qualities to our environment. Sustainable dark sky compliance often simplifies the impact and effect of buildings as components to our relationship to architecture in a nighttime setting. We seek to reach a balance.
DiLouie : Some may find the glittering skyline beautiful; others see it as an incredible waste of money and finite energy resources while contributing to light pollution that obscures our view of the stars. A building with well-designed fa%%CBOTTMDT%%ade lighting and with the interior lights shut off makes a highly aesthetic contribution to the urban nightscape.
Haran : First of all, lighting the top of a building consumes only a small fraction of its total energy. It's the floors of a building, not its crown, that enlarge the carbon footprint. By doing a modest amount of decorative lighting, you prevent the city from feeling like a ghost town. That encourages more people to live in dense urban areas. And density saves energy. A green city is not a blacked out city. “Is a planet without the things that inspire us worth saving anyway?”
Secondly, there is the bird issue. In Chicago and other cities, thousands of migrating birds die each year because of collisions with skyscrapers whose bright lights and reflective glass make them disoriented. In 1999, Chicago became one of the first cities to encourage building owners to dim lights during bird migration season. The city's “Lights Out” program calls for steps such as lowering or turning off exterior decorative lights from 11 p.m. to sunrise to protect migrating birds. The Chicago program correctly recognizes that a building is not fully green unless it responds to the needs of birds as well as the needs of people.
CSE: What is a good way to decide which controls approach is best for a particular application? How do budgets, O&M considerations, and functional and performance requirements come together?
Haran : Lighting control is perhaps the most important element of any lighting energy conservation program. Its benefits are concrete, measurable, and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on.
For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore ideal for time-based controls. If lighting is needed on a more random basis, such as in private offices, occupancy sensors provide a better level of control and greater energy savings.
Wise : I go for what in statistics is called the “maximum entropy” solution, or in Game Theory, what is called a “saddle point” on the hull of the criteria space. In other words, use a controls approach which gives you the maximum net benefit across all of the criteria you are going to use to evaluate the controls strategies. This ensures that at least the minimum of all criteria are met, and that the benefits to be had are spread out the most widely across all criteria of interest.
Craig DiLouie Education Director,
Siva K. Haran , PE, LC, LEED AP,
Chief Electrical Engineer/Director of Lighting,
Rodrigo Manriquez , IALD, LC, IESNA, Principal, Senior Lighting Designer,
James Wise , PhD Sustainability Coordinator