Adecade after Congress passed the Energy Policy Act of 1992, the U.S. Dept. of Energy (DOE), acting on its authority granted by the bill, designated ASHRAE/IESNA Standard 90.1-1999, “Energy Standard for Buildings Except Low-Rise Residential Buildings,” as the national energy standard. (The DOE determined that Standard 90.1-1999 saved up to 6% more energy than the previous Standard 90.1-1989 in the Act.) At that time, the DOE mandated all states have a commercial energy code — one that is at least as stringent as 90.1-1999 — in place by 2004 or provide justification for noncompliance.
Since then, most states have complied, adopting Standard 90.1-1999; its updates, Standard 90.1-2001 or 90.1-2004; a version of the International Energy Conservation Code (IECC) set by the International Code Council (ICC), Washington, D.C.; or their own state-specific codes, such as California's Title 24 — all of which stipulate mandatory lighting controls. A majority of state energy codes require automatic shutoff of all lighting in commercial buildings greater than 5,000 square feet. Some codes, such as California's Title 24, are even stricter, requiring daylighting controls in some spaces, as well as commissioning for control systems.
“As a result of this wave of commercial energy codes, automatic lighting controls have become the norm rather than the exception in new construction,” says J. Glaser, president, Rosslyn, Va.-based Lighting Controls Association (LCA), an adjunct of the National Electrical Manufacturers Association (NEMA), also based in Rossyln, Va.
The biggest influence on the installation of lighting control systems, building owner and engineer awareness of the energy efficiency offered by these systems seems to be increasing. However, the industry still faces low end-user awareness, as well as other critical components: compatibility with Building Management Systems (BMS) and communication among members of the design and installation teams.
The apparent complexity of lighting control systems and concerns about interoperability with other building systems have limited their applications, says the National Lighting Product Information Program (NLPIP), Troy, N.Y. “Unfortunately, the advances in BMS aren't keeping up with the advances in lighting control,” says Joseph Good, LC, FIES, IALD, USITT, LEED AP, principal, Spectrum Engineers, Salt Lake City. “The BMS people don't think they need to listen to the lighting industry. They think that if they put a lighting panel in Division 15 or 25, they've done their job. If there's not a wall station or access to the lighting from where it needs to be, then it's not really serving what the users need.”
Compounding the technology compatibility problem is the lack of interaction among the disciplines. “They're taking off in two different directions in some ways,” Good says. “I wish they would talk to each other a little bit better, but everybody's convinced they're right so nobody's particularly doing the right things.”
Good breaks down lighting control into two separate levels. On one hand, lighting control is implemented strictly for code compliance and energy management. “That is fairly constructively communicated,” Good says.
Where the separate camps get into trouble, however, is when lighting controls provide for aesthetics or effect. “Then they're not even talking the same language,” Good explains. “If you say the word ‘control point’ to lighting designers, they will have no idea what you're talking about. If you use the word ‘preset’ to building management, they have no idea what you're talking about. These are fundamental terms in each other's vocabulary.”
Good says all too often lighting designers are willing not to think about what happens when the drawings leave their office. “That's a missed opportunity for coordination,” he says. “Lighting designers are going to have to think about how the electrical engineer or the BMS system — or both — is going to control the lighting they're putting on the job.”
However, some lighting designers feel their hands are tied, so they leave the controls systems to the electrical engineer. “I do not — nor do many lighting designers — specify building control systems,” says Mike Noon, LC, Palindrome Lighting Design, Crofton, Md. “That task almost always falls to the electrical engineer because it is intrinsically linked to the building power supply distribution network. Lighting designers who are not also practicing electrical engineers are precluded by liability insurance from doing panel design work.”
Nevertheless, Good says lighting designers should be interested in lighting's interoperability with BMS systems because they're the ones who tend to think about lighting and controls for the benefit of occupants and owners, not the benefit of the technology. “A lot of lighting designers put equipment on a project because the project desires it or needs it — not because it's the latest and greatest and needs to be used,” Good says. “I think they're missing the boat in a lot of ways if they don't talk to the BMS.”
According to Good, the benefits of improved communications are many. “If a serial connection can come out of the BMS to a dimming system, and the relays controlling the lights can come to a wall station in a room, we avoid redundant equipment and provide the owner with something that works better,” he says.
Sometimes, even the control devices have trouble communicating using their own common language, otherwise known as a protocol. Some manufacturers have proprietary protocols, whereas others are open source. Devices designed according to the same protocol should be interoperable in the field when operating together as a designed system. When systems designed according to one protocol must communicate with a different protocol, a gateway device, which acts as a translator between the systems, must be used.
“A combination of control strategies is usually called for in larger commercial building projects,” Glaser says. “Many office, retail, and industrial buildings have been successful in using schedule-based systems as the backbone of the control system, supplemented by occupancy sensors, manual switches, timer switches, and dimming for perimeter areas, smaller rooms, special-use areas, and spaces where users are to be given personal dimming control.”
Good is certainly a fan of open protocols. “That makes it a little easier for various systems to at least do the research to be able to talk to each other,” he says.
The alternative to interoperable systems seems like antiquated technology to Good. “I'm still doing systems that have to go all the way down to the really crude technology of dry contacts, and that's not really elegant,” he says. “It's so much better if our lighting control status is fed back to the BMS so the operators of the BMS or the security station where you've got a control terminal know what the dimmers, relays, or lights are doing in any particular room.”
For the systems to work properly, they must first be designed into the project. Many of the state standards don't require the BMS to function with the lighting controls in that specific of a manner. That's why Good recommends working with USGBC LEED certification standards. “LEED is making these systems interact more, and it's making design teams pay more attention to unifying design elements to achieve common goals, like coordinating insulation with the HVAC system and with the lighting system to deliver a better project that works all the way around,” he says.
The lighting controls system, when installed as a component of BMS, can play a big part in whether a project will succeed or fail. Once installed, however, another team — the commissioning team — must ensure the elements of the design work the way they're supposed to. “Commissioning can make work what is put on the project by the design team and installed by the contractor,” Good says.
According to the LCA, commissioning can help ensure proper equipment operation, user acceptance, and intended energy savings in both new construction and renovation projects. “Commissioning,” as defined by Miami-based Florida Power & Light, a utility serving 8 million people in Florida, is the “systematic process of ensuring that all building systems perform interactively according to the documented design intent and the owner's operational needs.” This can include factory startup, sensor calibration and owner notification of the operation and intent of the control systems.
Optimal commissioning occurs when it is planned and budgeted, says the LCA. Before commissioning, the system's designer should provide a controls “narrative” that describes the functionality of the control system, details the commissioning requirements in the project specifications, and includes a sequence of operations for each control point.
Commissioning should involve all members of the design and construction team and is typically led by the commissioning agent, who may be an electrical contractor, commissioning specialist, manufacturer technician, or other professional. Field commissioning requires systematic testing of all controls in the building to guarantee that they provide specified performance and interact properly as a system.
During commissioning, it's helpful to understand the sequence of operation for each control point, which should be tested to make certain the control system delivers desired results based on typical operating conditions. Besides operating factors, other factors such as location of controls should be considered during field commissioning. In addition, commissioning may entail programming of microprocessor-based controls. Time of day, override, and event scheduling must be programmed and tested as well.
After commissioning, the commissioning agent should tell the owner and users about the intent and functionality of the controls, especially about overrides, local control capability that allows users to override a schedule, or master command. Moreover, the commissioning agent should turn over all documentation and instructions to the owner's maintenance personnel so they can maintain and re-tune the system as needed, implying that calibration and commissioning is an ongoing process. Maintenance personnel should inspect all lighting controls for proper operation at least once per year.
Costs and savings
Unfortunately, the devices that comprise lighting control systems sometimes come with high up-front and maintenance costs. A direct digital control system comprising 29 HVAC and lighting nodes costs approximately $4,700 for the necessary hardware, software, and installation, compared to a comparable centralized control system, which costs about $8,500, according to numbers from the NLPIP. The organization estimates that a direct digital control system with a few hundred nodes may cost upward of $25,000. The components range in price from as low as $50 for a binary direct digital control module to $4,000 for an Internet/intranet router. Setup costs range from $50 to $15 per node. Direct digital control systems may also be rented or leased.
To offset initial costs, owners and installers should check with their local electric utilities to see if they provide any rebates in exchange for limited ability to monitor the system and control electric loads during peak demand. To further help pay for the more efficient systems, a federal tax deduction is available until the end of this year (see Commercial Buildings Deduction sidebar below).
There's no dispute that advanced lighting controls can contribute to energy-efficient, productive, higher-value buildings. Controls reduce the amount of power drawn by the lighting system during operation and also the number of operating hours, thereby reducing utility energy charges. They can also reduce the amount of power drawn by the lighting system, reducing utility demand charges, particularly during peak demand periods when demand charges are highest. According to the New Buildings Institute (NBI), White Salmon, Wash., lighting controls can reduce lighting energy consumption by 50% in existing buildings and by at least 35% in new construction.
These savings can produce a short payback and a high rate of return for the investment in the new controls. In new construction, the rate of return is often higher because only the premium, not the total installed cost, will be recouped before positive cash flow is realized.
Automatic switching and dimming controls are typically used to achieve significant energy savings via occupancy sensing, scheduling, load shedding, and daylight harvesting. Manual dimming controls can save energy, but their primary purpose is to support visual needs.
“Scheduling has been demonstrated to generate 5% to 15% energy savings whereas occupancy sensors have demonstrated 10% 50% or more energy savings,” Glaser says.
Bi-level switching, a manual or automatic control (or a combination of both) that provides at least two levels of lighting power in a space (not including OFF), typically produces a 10% to 15% energy savings, according to NEMA.
Figures from the U.S. Environmental Protection Agency (EPA) credit the use of occupancy sensors with substantial energy savings. The amounts can range from 40% to 46% in classrooms, 13% to 50% in private offices, 30% to 90% in restrooms, 22% to 65% in conference rooms, 30% to 80% in corridors, and 45% to 80% in storage areas.
According to most industry experts, scheduling and occupancy sensors are currently the most common lighting control devices, with demand driven by prevailing commercial energy codes. Fluorescent dimming is gaining in popularity as both an energy management strategy and as a way to support workers' visual needs by enabling them to adjust local light levels in traditional dimming spaces, such as conference rooms, and nontraditional dimming spaces, such as offices (see Power to the People on page 46).
In the future, lighting controls will be run mostly on digital devices, instead of analog. According to Glaser, the benefits of digital are distributed intelligence, which canincrease reliability; distributed control, which can enable more granular scheduling control in an economical manner; “install and forget” occupancy sensors, which minimize nuisance switching and maximize energy savings; and wireless RF controls, which promise the benefits of building a centralized lighting control network without low-voltage wiring.
LCA calls wireless control “one of the most exciting frontiers in lighting control and energy management, offering significant potential benefits for residential and nonresidential lighting systems, large and small buildings, and existing buildings and new construction.” New technologies that will redefine wireless control by dramatically expanding its utility are now being commercialized.
Sidebar: Commercial Buildings Deduction
Until Dec. 31, 2007, building owners who adopt energy-efficient building systems can take a deduction for those systems under the Energy Policy Act of 2005's (EPAct 2005) Commercial Buildings Deduction. In the year the systems are installed and put to use, owners may deduct the full cost of the systems, as opposed to depreciating their cost over time. With regard to lighting control components and systems, the deduction may be taken for using technologies that meet or exceed that standard, ASHRAE/IES Standard 90.1-2001. In all cases, the building must be located within the boundaries of the United States or its territories.
For a complete deduction, owners must achieve a 50% savings in total annual energy and power costs with an upgrade in lighting and lighting controls, HVAC/hot water, and the building envelope. In this case, the owner can deduct the full cost of the more efficient systems, capped at $1.80 per square foot.
A partial deduction allows the owner to upgrade either lighting/lighting controls or HVAC/hot water or building envelope. If the upgrade results in a 16 2/3% savings in total annual energy and power costs, the owner can deduct the full cost of the more efficient system, capped at $0.60 per square foot.
Under Interim Lighting Rules, if the owner reduces interior lighting power density (LPD) by at least 25% to 40% of the minimum requirements of Standard 90.1-2001, the owner may deduct the full cost of the new lighting, capped at $0.30 to $0.60 on a sliding scale. For warehouses, however, the owner must reduce lighting power by 50% to qualify for a maximum tax deduction of $0.60 per square foot. Furthermore, Interim Lighting Rules require bi-level switching in all occupancies except hotel and motel guestrooms, store rooms, restrooms, and public lobbies, require controls and circuiting that complies with Standard 90.1-2001 — and require that light levels meet the minimum levels as published in the Ninth Edition of the “IES Lighting Handbook.” (Partial deduction rules do not require these terms).
For more information on receiving deductions for lighting/lighting controls energy efficiency improvements and to download a pdf of the guidelines, visit the Commerical Buildings Tax Deduction Coalition Web site at www.efficientbuildings.org/PDFs/internal-rev-bulletin06-26.pdf. NEMA's Lighting Systems Division also provides a Web site that explains the rules in greater detail. You can visit it at LightingTaxDeduction.org.
Sidebar: Power to the People
“Workers tend to be more productive in a well-lit space that fosters better visual comfort,” says the lighting controls design brief from Energy Design Resources, an online portal administered by the California Public Utilities Commission to educate architects, engineers, lighting designers, and developers about techniques and technologies that contribute to energy-efficient nonresidential new construction. Many engineers now recognize the need to adapt lighting for multiple uses of a space.
The brief cites as an example an office building that installed daylight dimming controls and experienced a 15% decline in absenteeism. A government laboratory discovered that when it gave workers more control over lighting levels they used the controls to improve their visual comfort as well as to save energy.
As the documented benefits of giving users dimming control of local lighting become more recognized, and as daylighting becomes more popular in construction — thereby presenting opportunities for daylight harvesting controls — dimming and other strategies are expected to continue to grow in popularity.
According to the Building Owners and Managers Association, energy costs run about $2 per square foot in a typical commercial building while worker salaries and benefits can run to $130 per square foot or more. Although reducing energy costs by a large percentage can be profitable, increasing productivity by even a very small percentage can be much more profitable.