LED luminaires provide lesson in energy savings

by Mark Bolton, IESNA
A distressing fact faces those who operate K–12 educational institutions across the country. According to the U.S. Department of Energy’s (DOE’s) and Environmental Protection Agency’s (EPA’s) EnergyStar, primary and secondary schools are spending a staggering $6 billion annually on energy—more than on textbooks and computers combined. This equation is disturbing, and there are ways to lower schools’ utility costs.

According to the U.S. Green Building Council (USGBC) Build Green Schools website:

If a green school saved $100,000 per year in operational costs, it is roughly enough to hire two new teachers, buy 200 new computers, or purchase 5000 new textbooks.

Additionally, USGBC has determined if all new school construction and renovations went ‘green’ today, energy savings alone would total $20 billion over the next decade.

California is the nation’s largest school system with more than 10,000 schools, 70 percent of which are more than two decades old. According to the California Energy Commission, schools in the state spend $700 million a year—or nearly three percent of their total budget—on energy. By employing energy efficiency in the state’s schools, the system could reduce energy bills by 20 to 40 percent, leaving funds for other educational priorities.

The following statistics are notable:

• according to EPA, the average school retrofit reduces energy costs by approximately 30 percent;¹
• more than 80 percent of average school energy consumption is used for heating, cooling, ventilation, and lighting systems;²
• energy improvements, such as increased daylighting, have the potential to save schools $1.5 billion annually while simultaneously creating a better learning environment; and
• the country’s least energy-efficient schools use nearly four times as much energy per square foot as the most efficient.³

Additionally, DOE’s Guide to Operating and Maintaining EnergySmart Schools suggests nearly one-third of the energy consumed in the average U.S. school is wasted. For example, gymnasium and stairwell lights are left on at full brightness during periods of non-occupancy. This wasted energy consumption can be easily addressed through use of sensorlight-emitting diode (LED) lighting systems, which translate into cost and energy savings to the school.

The good news is energy is one of the few expenses that can be decreased without negatively affecting classroom instruction. By implementing improved operations and maintenance strategies, and incorporating efficient equipment into retrofits, school districts can generate substantial cost savings while improving the physical environment for students and teachers alike.⁴

Moving the needle
The U.S. Department of Energy has calculated lighting in institutional facilities can consume up to one-third of a building’s total energy cost. Traditionally, lighting has been viewed as a fixed expense, but this statistic, combined with technology advances and engineering, means lighting can be given a closer examination as a budgetary line item.

Former U.S. Secretary of Energy, Steven Chu, has repeatedly said, “Energy efficiency isn’t just low-hanging fruit; it is fruit lying on the ground.” To that end, one of the quickest return-on-investments is retrofitting traditional lighting fixtures with LED luminaires.

DOE has heralded LEDs as the future of lighting because they have an extremely long lifespan when compared to fluorescent lighting, in many cases lasting 10 times longer.

LED background and advantages
LEDs have been around for more than 40 years. The small, solid-state devices can be used to produce millions of different colors and brightness of light, while using less energy than traditional lighting methods.

LEDs fall under solid-state lighting (SSL) technologies. The term solid-state refers to the fact the light in an LED is emitted from a solid object (i.e. a block of semiconductor), rather than from a vacuum or gas tube, as in the case of incandescent and fluorescent lighting. Solid-state refers to electronic components, devices, and systems based entirely on the semiconductor.

LEDs create light differently than conventional forms. Other lighting technologies, such as halogen and incandescent sources, heat up a fragile filament until it radiates light, wasting large amounts of electrical energy through infrared radiation. Conversely, LEDs convert an electrical current directly into light so less energy is wasted. LEDs do not burn out as a standard lamp does, so individual diodes do not need to be replaced. Instead, the diodes gradually produce lower output levels. In fact, well-designed fixtures can last up to 50,000 hours or longer; further, when one LED fails, it does not necessarily result in a complete fixture outage.

Due to their long life, LEDs are virtually maintenance-free and the energy savings they represent is often quite dramatic. LEDs also re-strike instantly after a power interruption and can be controlled with occupancy sensors. Well-designed LED luminaires may operate between 50,000 and 100,000 hours, and deliver at least 70 percent of their initial performance at their ‘end of life.’

Lumen maintenance describes how long a lighting fixture retains a certain percentage of its initial light output. White light sources, such as LEDs, used for general illumination are commonly considered to be at the end of their useful life when the light output falls below 70 percent of initial output.

Durability
LEDs are solid-state devices containing no moving parts, no filaments, or fragile glass to break—this eliminates the risk of damage during transportation, installation, and operation, even in the toughest environments such as public access areas where fixtures are routinely subjected to attempts of vandalism and abuse. Additionally, as explained above, LEDs have longer lifespans than various other traditional light sources.

Sustainability
LEDs are considered more sustainable because they decrease the need for additional power plants, which cause the release of potentially damaging carbon dioxide (CO₂) into the atmosphere. Additionally, LED luminaires have an environmental advantage as they contain no mercury and are Restriction of Hazardous Substances (RoHS)-compliant.

RoHS restricts the use of lead and other materials in electronic component products. The program’s purpose is to reduce the influence of these substances on the environment.

Since LEDs do not contain significant amounts of harmful components and are RoHS-compliant, they can be disposed of and recycled in the same way as an ordinary light bulb. Additionally, some manufacturers offer product recycling to customers at the end of the LED’s lifetime. At least 80 percent of the luminaire’s material by weight is recyclable at end-of-life and is designed for disassembly per International Standards Organization (ISO) 14021, Environmental labels and declarations–Self-declared environmental claims (Type II environmental labelling).

High-source efficacy (i.e. lumens per watt)
Efficacy is a term normally used in cases where input and output units differ. In lighting, the amount of light (in lumens) produced by a certain amount of electricity (in watts) is the concern. Significant advances in LED efficacy have recently been introduced by suppliers. As a result, the lumen output of these LEDs has substantially increased. How long is 100,000 hours? Based on the length a fixture is illuminated per day, the translation of a 100,000 hour lifetime into an annual basis can be seen in Figure 1.

LEDs in action
With more than 350 schools covering more than 2.2 million m² (24 million sf), the Clark County School District (CCSD) is the fifth largest and fastest growing school district in the United States. CCSD’s Facilities Division is also one of the most comprehensive, sophisticated, and sustainable design-oriented districts. They are in the process of building more than 100 new schools to meet the tremendous growth of the greater Las Vegas metro area. All of the new schools will target Leadership in Energy and Environmental Design (LEED) Gold certification.

In addition to this new construction, the district is implementing extensive renovation and modernization at existing facilities, such as Ed W. Clark High School. Built in 1964, the high school serves approximately 2070 students. Steve Johnston, CCSD design manager for the modernization project, is overseeing the ongoing $30-million renovation that includes:

• HVAC and plumbing upgrades;
• locker room improvements;
• food service kitchen;
• science labs;
• fire/sprinkler system;
• technology advances such as local area network (LAN) and classroom projector installations; and
• daylighting in the student activity center.

Additionally, because of a federal grant, an upgrade to the inadequate and outdated exterior lighting system was considered.

Working with Johnston on this renovation was Jeff Iverson from TJK Consulting Engineers. Wanting to reduce energy consumption and costs, Johnston and Iverson looked into LED luminaires compared with other lighting technology but found no comparison regarding the efficiency or quality of illumination. Previously, the school had 91 of the 70-Watt high intensity discharge fixtures installed in overhangs and doorways. In a one-for-one replacement, the school now has the same number of 23.1-Watt LED canopy and wall-mounted exterior luminaires—almost a full replacement of exterior luminaires on the school grounds. This LED installation is reducing the school district’s energy consumption by 75 percent over the incumbent fixtures.

Providing a safely illuminated campus during evening hours was also an important reason for selecting new lighting.

Reduced luminaire maintenance is a benefit welcomed by Jack Viscosi, CCSD’s electrical/mechanical repair coordinator, responsible for the electrical maintenance at Clark High School. The lifetime of an LED, approximately 100,000 hours, allows for increased performance and reduced maintenance compared to traditional lamp sources.

Las Vegas has a dry desert climate leaving little moisture in the air to retain daytime heat resulting is low night temperatures. LEDs can thrive in cold environments, unlike fluorescent light whose performance is greatly affected by cold temperature.

This is the CCSD’s first LED luminaire installation, but it will not be the last. A commitment to reducing energy consumption and environmental stewardship will help facilitate additional sustainable projects as funds become available.

The $30-million renovation is funded largely through a 1998 voter-approved bond fund, and federal grants specifically for the lighting upgrade, as well as a solar thermal grant for the installation of an adsorption chiller in the central plant to control the school’s cooling.

Conclusion
According to the U.S. National Center for Education Statistics (NCES), there are currently 98,706 public schools and 33,740 private and parochial schools in the country. The amount of resources that could be redirected toward education, hiring teachers, and buying necessary classroom materials if an energy-efficiency program was implemented is clearly sustainable.

DOE reports state and local agencies are planning to invest more than $60 billion over the next three years to build or renovate schools. Now is the time for schools to employ more sustainable products, such as LED luminaires, as a catalyst to significant improvements in energy efficiency.

Notes
¹ For more, see the U.S. Environmental Protection Agency’s (EPA’s), Energy Efficiency Programs in K–12 Schools: A Guide to Developing and Implementing Greenhouse Gas Reduction Programs. (back to top)
² For more, visit www.tcng.org/blog/post/browns-budget-reflects-need-to-invest-in-school-energy-efficiency. (back to top)
³ See U.S. Department of Energy’s (DOE’s) Buildings Technologies Program book, Guide to Operating and Maintaining EnergySmart Schools. (back to top)
⁴ Visit www.energyright.com/business/pdf/Schools_ESCD.pdf. (back to top)

Mark Bolton, IESNA, is regional sales manager at Gurnee, Illinois-based Kenall, which produces and supports lighting solutions for demanding environments. He has worked for lighting manufacturers for the past 34 years in numerous sales capacities, such as regional sales manager and regional vice president of sales. Bolton can be reached at mbolton@kenall.com.

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