Thanks to the new lighting products and technologies, sustainability and energy efficiency is within reach. With the correct knowledge, these solutions can be put to good use in commercial and industrial facilities, saving time and money, while benefiting the environment. Understanding the basics of energy efficiency and investigating unconventional concepts will help increase the productivity, comfort and well-being of the users of the space and empower companies to become more sustainable.
Why are more and more companies switching to energy-efficient lighting? The reasons include a reduction in energy bills and greenhouse gas emissions, and state laws that are beginning to mandate energy-efficient systems in new buildings. In addition, the advancements in new lighting technologies are improving working environments, enhancing productivity and affecting the bottom line. The benefits of switching to energy-efficient lighting in a work environment include:
Optimized uniformity and enhanced visual comfort.
Models that vary in energy efficiency up to 90 percent.
Energy reductions of one-third or more compared to conventional lighting.
Solutions designed for every application.
To implement energy-efficient lighting, lighting designers, electrical contractors, facility maintenance personnel and other installers must have a basic understanding of luminaires and the ability to match them to the need. There are two types of luminaire optical designs for interior spaces: directional and diffuse.
A light in a stairwell or overhead lights shining on pathways are good examples of directional lighting. Directional lighting uses the optics from the reflector housing, the mounting surface that directs the light to a certain area, and the optics from the louvers or aluminum baffles, which are the curved cone-shaped fixtures that act as a glare shield. Directional lighting gives you ultimate control because you can “direct” the light.
Diffuse lighting systems “throw” light everywhere with less control of the distribution affecting their glare. Offices and warehouses offer many good examples of diffuse lighting systems. They enjoy a higher efficiency rating than directional lighting. Indirect lighting, a type of diffuse lighting design, is said to be easier on the eyes and a preferred lighting system by the building's occupants. However, indirect lighting does not enjoy good efficiency ratings (less than 50 percent), since it reflects off ceilings. If indirect lighting is used, it should be evenly distributed to avoid excessive luminance. Like an overcast day, indirect lighting can provide a calm, diffuse light without highlights or shadows.
The type of lighting you choose depends on the area you are lighting. Nonetheless, both types of lighting can be made more energy efficient based on the selection of the lamps and fixtures.
Energy-efficient T-8 and T-5 lamps were introduced in the 1980s and the 1990s, respectively. The original T-8 and T-5 lamps had an average life of 20,000 hours and provided individual energy savings from 5 percent to 20 percent. Their invention and the second generation of the lamps later changed the face of the lighting industry. These lamps need fewer watts to produce the same lighting as inefficient fluorescents. They also lower utility costs and reduce the amount of greenhouse gas that harms the environment. When T-8 and T-5 lamps are installed with their properly matched ballasts, energy savings can improve from 30 to 50 percent. This replacement also offers greater lighting control and improves the comfort of the space for its occupants, leading to greater productivity.
New luminaire optics have been developed in response to the energy-efficient T-8 and T-5 lamps. Design approaches have focused on two-lamp executions, competing with typical parabolic, or cone-shaped, three-lamp units with traditional fluorescent lamps. These two-lamp executions deliver optimum light distribution, aesthetic appeal and increased energy savings. Additionally, these controlled light outputs can create excellent lighting for vertical surfaces by illuminating the upper quadrants of the surrounding walls to eliminate the cave effect created by parabolic luminaries. These new designs deliver highly controlled distributions with excellent uniformity and visual comfort and very high luminaire efficiency. Models are available in excess of 90 percent efficiency and provide energy reductions of one-third or more compared to conventional recessed lighting. In addition, the new designs will also help companies meet or exceed stringent energy standards such as ASHRAE 90.1 and California's Title 24.
Energy-efficient two-lamp T-8 systems are an excellent solution to many lighting problems. The design of these lamps and ballasts allow for further spacing of the lamps, from 10 feet to 12 feet apart, without any reduction in light quality. Another design option would be to consider selecting a high light output system, where you can space the luminaries 14 feet to 16 feet apart. It's important to note that the advantage of fewer luminaries is only possible if glare is well controlled within the luminaire and further spacing does not negatively impact the uniformity. By using either one of these options, similar lighting levels can be achieved with fewer lamps and ballasts while also saving on utility bills. The following are six simple factors for improving lighting energy efficiency:
Normal fluorescent lamps cycle on a schedule of three hours on, 20 minutes off — the industry standard. These lamps have been rated at an average of 50 percent survival rates — only for 20,000 hours — when they operate in this manner. Manufacturers have started publishing longer lifetimes when operating these lamps on burning cycles more relevant to their environment (for example, 10-hour to 12-hour building operation cycles). Ask your lighting representative the survival rate of each lamp. “Super” T-8s have improved components and manufacturing techniques allowing manufacturers to increase their lamp lifetimes to levels above 24,000 hours to 36,000 hours and light output levels by 10 percent.
Another way to improve lamp lifetimes is to control the electrode sputtering in each start cycle. Program start ballasts are thus preferred since they provide a much softer starting of the lamp. Instant start ballasts, on the other hand, will have an effect of reducing lamp lifetimes by 15 percent to 25 percent if the lamp is not designed for that type of starting operation.
New T-5 lamps, which have 40 percent smaller diameters than standard T-8s, provide manufacturers with design opportunities for more compact housings with optimized optical designs. Fluorescent lamps are temperature sensitive. Furthermore, T-5 systems inherently have optimum light output performance at 35 Celsius (95 degree Fahrenheit), which is 10 degrees Celsius higher than the peak light output performance of T-8 lamps. T-8s are designed to peak at room temperature. This provides for an improved T-5 light output performance when the lamps experience a higher ambient, which is mostly the case in enclosed luminaires. T-5 systems are also offered in high-output versions (HO) that can allow a lighting system to yield required light levels on the work-plane, but with fewer components. HO versions reduce the overall investment cost for lighting a building.
Fluorescent electronic ballasts
The selection of the appropriate lamp/ballast combinations has become a more complex task due to the multitude of offerings. This is an advantage for end-users and specifiers. Electronic ballasts perform better than previous magnetic systems due to reduced ballast losses and the improvement in lamp performance due to high-frequency operation. Coupled with the capabilities of controllability and dimming management, electronic ballasts for fluorescent operation will help drive the industry to a 100 percent electronic market, as mandated by government regulations. In fact, the market has embraced electronic ballasting as the preferred choice for operating fluorescent systems due to the additional product benefits including reduced noise levels, flicker-free operation, controllability of harmonic distortions and power factors.
Placement of fixtures
You must put light where it's most needed. Pay close attention to areas over employees' desks, where they spend the majority of their time. In addition, you'll also want to eliminate dark spots between fixtures. In most cases, the design of a fixture leads to these dark spots. When a lamp burns out in a directional lighting fixture, the design limits the ability of surrounding lamps to compensate.
Another excellent way to achieve maximum energy-efficiency is to incorporate natural light into your workspace. Consider natural lighting because it can help reduce the glare that can be caused by a lighting system producing more light than needed. This can be seen in offices where employees next to windows are forced to pull the drapes closed to see their computer screens. A well-designed lighting plan will take into account this free light and maximize its use.
To make the best use of natural light and interior lighting, several new products on the market can accommodate your needs, including automatic controls with dimmer functions and stepped ballasts that allow you to only use a portion of the lamps. Some commercial applications are also performing daylight harvesting — by dimming the lights on one side of their property to use as much natural light as possible. These facilities generally use less light on the east side of their property when the sun is out, and then increase the amount of light as the sun goes down. Conversely, they adjust the lights on the west side of the property.
For those areas where natural light cannot be seen, it's a good idea is to integrate light wells to deliver light deep into the interior of the space. Light wells are open spaces, typically known as sunroofs in residential applications, that allow natural sunlight into an area.
Materials and finishes can have huge impact on lighting in your space. Interior designers say painting a room a dark color can make it look smaller. That dark color can also absorb more light, forcing your eyes to adjust to lower light levels. Rooms painted a light color help a person perceive the space as larger and aid in lighting.
In addition, keeping reflective surfaces to a minimum can also help. Unexpected glare from floors and windows can affect the lighting of the space. The materials used within a facility need to be considered when designing a lighting plan. Another useful technique is to light the walls in your space. At lower wattages, lighting the walls can increase the perception of brightness.
When lighting an outdoor space, keep in mind that light pollution can be a problem. Good examples of light pollution and its negative effects are high school football fields, retail centers and parking lots. In this type of diffuse lighting where lamps light a large surface area, light pollution occurs when the excess light spills over onto nearby houses, lighting the streets and backyards and generally creating a nuisance for the surrounding neighbors. It's important to keep the surroundings of a facility in mind when designing an outdoor space. Not only does it cause potential problems with neighbors, it can also increase costs on utility bills.
The U.S. Green Building Council (USGBC), Washington, D.C., has developed a standard rating program that encourages the adoption of sustainable and green building practices. The program, the Leadership in Energy and Environmental Design (LEED), helps rate new and existing buildings on their sustainable practices by taking into account everything from construction and storm water design to light pollution reduction. Although not the standard yet, LEED certification is quickly becoming a distinction that many tenants are seeking to reduce energy costs across the life of their lease. For more information on LEED visit www.usgbc.org.
Techniques that properly drive light deep into interiors, internal materials and finishes can all affect lighting and, ultimately, a company's efforts to become sustainable. In addition, controlling the direction and intensity of light and eliminating glare can have a huge impact on the comfort of the users of the space. Going forward, more new buildings will be LEED certified and the added emphasis on energy efficiency will impact every business. By taking the steps now to ensure that their lighting systems are as energy efficient as possible, businesses will enjoy even greater energy savings, help the environment by becoming more sustainable, and give workers a comfortable environment to enhance productivity.
Charles E. Israel has been a lighting designer for over 20 years. In 1992, he founded Lighting Design Alliance (LDA), a full-service architectural lighting design firm with 27 employees and offices in Los Angeles, Chicago and Dubai, United Arab Emirates. Israel's design experience includes building facade lighting, custom fixture design, corporate office spaces and themed hotels and resorts. The Borgata Hotel & Casino in Atlantic City; Endeaver Talent Agency in Los Angeles; Cheesecake Factory restaurant in Rancho Mirage, Calif.; Port of Los Angeles; and the Harvey Nichols shop in Dubai are some of LDA's recent landmark projects. Israel graduated with a degree in Architectural Engineering, Environmental Systems from Pennsylvania State University.
Nick Bleeker has over 20 years' experience in the lighting industry in both the technical and commercial aspects of the business. In his current role as director of business development at Day-Brite/Capri/Omega, he is responsible for implementing programs and policies that support the company's marketing and growth strategies such as steering the division's overall sustainability programs. He recently led the project teams for the design and construction of the $2-million dollar Day-Brite/Capri/Omega Lighting Institute, which has received LEED-CI certification. Bleeker holds a M.B.A. and a B.E. in Mechanical Engineering from Vanderbilt University in Nashville, Tenn.