Consulting-Specifying Engineer - December 2008 - (Page 22)

M/E Roundtable 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 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? 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. Careful selection, design, and mounting of lighting equipment will yield energy efficiency, while offering great aesthetic qualities to our environment. – Rodrigo Manriquez 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. 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 façade 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 22 Consulting-Specifying Engineer • DECEMBER 2008

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Consulting-Specifying Engineer - December 2008 Contents Viewpoint News M/E Roundtable ARC Awards New Construction Gold New Construction Silver New Construction Bronze Renovation Gold Renovation Silver A Green Approach to Air Conditioning Systems Turning Down the Lights Case Study New Products Equipment Lifecycles Advertiser Index Green Space Gas Technology Pure Power Supplement

Consulting-Specifying Engineer - December 2008

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