Lighting as the Unsung Hero in Data Center Energy Efficiency

January 4, 2012 6 Comments »
Lighting as the Unsung Hero in Data Center Energy Efficiency

Data center facilities managers know that “green” matters. In addition to the energy cost savings, embracing earth-friendly practices helps guarantee compliance with increasingly strict environmental regulations and helps brand the company more favorably.

But going green can also mean getting smart. Increased building intelligence results from streamlined energy control—a synergy that requires a convergence of IT and building-performance systems. When data centers achieve this integration, they operate more simply, cost less and maximize energy efficiency. What lies at the heart of this convergence? It’s probably not what you would expect.

It’s lighting.

Networked LEDs 101

Lighting may not seem significant to energy efficiency, at least at first glance. After all, it accounts for only 3 to 5 percent of a data center’s electrical load. But lighting can make a much larger impact on a data center’s power usage effectiveness (PUE), and switching to an energy-efficient lighting network that integrates building-performance systems can improve PUE by up to 25 percent.

It’s not the average light bulb that can streamline the operations of sprawling data centers, however. Only an intelligent lighting system can (and does) do the job. To understand how a building-performance lighting platform can serve as the catalyst to creating significantly more-efficient data centers, it’s important to look at the heart of the lighting system: networked light-emitting diodes (LEDs).

Since their introduction in 1962, LEDs have offered an efficient source of semiconductor-powered lighting that also brings improved lighting quality. LEDs mimic the spectrum of daylight better than fluorescents, avoiding the green undertones characteristic of the latter. This better spectrum makes distinguishing the colors of different wires and cables much easier. The uses for LEDs have expanded since their inception from indicator lights on devices to full commercial lighting platforms, and their practicality should only continue to rise: according to Haitz’s law, named for scientist Roland Haitz, with each passing decade, the cost per unit of emitted LED light falls by a factor of 10, while each LED package generates 20 times more light per wavelength.

The LED bulbs alone carry several environmental and efficiency benefits not seen in other commercial lighting options. The fixtures last for 50,000 hours—four times as long as commonly used fluorescent lights—thereby demanding significantly less maintenance than traditional lighting. Additionally, when LEDs are dimmed by 30 percent, they realize a 50 percent overall power reduction and a significant drop in energy expenses. With fluorescents, a 30 percent dim amounts to only a 20 percent overall decrease in power consumption. LEDs also help reduce cooling capacity demands by generating a much lower heat load than their fluorescent cousins. In fact, there is a reduction in heating load by 1 watt for every 3 watts of lighting reduction. Also, whereas fluorescents send heat down into the workspace, the limited amount of heat generated by LEDs is conducted up into the plenum cable without affecting temperatures in the server areas.

Recognizing these benefits of LEDs, connecting the lights via a direct current (DC) powered network maximizes their utility. The LEDs run on low-voltage category cable on a platform that comprises four key components. First, a central power engine transmits energy to the LED fixtures. Second, each fixture has an adapter containing multiple sensors, and the adapters connect the fixtures back to the central engine. Third, algorithms process the data gathered by the sensors to provide light at the right times and in the correct locations. Lastly, management and monitoring technology stores the data from the sensors.

This lighting infrastructure optimizes LED effectiveness by enabling countless specialized features. Data centers can customize their lighting systems to suit their particular lighting needs by employing any (or all) of these examples of energy-efficient capabilities:

• Sensor-driven, occupancy-based lighting to ensure lights only activate when employees in various areas of the data centers need them. If constant lighting is preferred, minimal light levels can offer energy savings while still providing enough light to support necessary functions like video surveillance.
• Daylight harvesting, which automatically adjusts light levels to maximize the use of available sunlight for administrative areas of the facility.
• Lighting policy scheduling that accommodates lighting needs at different times of day, on different days of the week, on holidays and during seasonal adjustments.
• Automated alerts to inform facilities managers of fixture outages.
• Fixture-specific data collection, enabling analysis of each light’s use to inform any necessary fine-tuning and to minimize wasted energy and money.

All of the above lighting-specific applications not only help data centers solve pressing energy issues, but they also scale with organizations as they expand or change their data facilities. Networked LED lighting brings data centers unparalleled flexibility, as its infrastructure accommodates technological advancements, space reconfigurations and temperature fluctuations. Once data centers have their lighting platforms in place, they have the energy-efficient engine they need to power all of their lights as well as to enable a range of building intelligence applications—for years to come.

Data center lighting

Diagram depicting the primary data center applications enabled by building-performance lighting.

From Green to Smart

Lighting is ubiquitous in all interior spaces, wired for power delivery and often deployed in a pervasive, grid-like pattern. It is the most logical platform and cost-effective place to integrate a pervasive sensor network. A building-performance lighting system can deliver value to data center operations far beyond lighting with a smart fabric that senses and reports on multiple environmental parameters. Through a single, flexible platform, the lighting system uses multiple environmental sensing points to monitor potential disruptions to uptime. Integrated data generation can report on room temperature; airflow, pressure and vibration; and the presence of particulates such as dust or smoke. Additionally, stored information on occupancy patterns not only informs lighting, but it also dictates optimal space usage and effective security protocols. With building-performance lighting, facilities managers need only check one source for key information on their data centers.

Some examples of building intelligence applications under the control of the lighting network include the following:

• Comprehensive sensor grids that generate detailed data on the thermal behavior or air quality within the server space.
• Automated emails that alert facilities managers to wayward temperatures or particulates.
• Alerts that indicate unauthorized occupancy in specific areas of the data center.
• Verification of security walkthroughs.
• Remote monitoring and control of the lighting system to be able to, for example, flash a light to guide a visiting repair technician.

With streamlined lighting and building-performance systems in place, data centers stand to significantly reduce their energy consumption. This reduction in energy use helps put data centers on the path to Leadership in Energy and Environmental Design (LEED) certification, earning potential credits in categories including energy efficiency, indoor environmental quality and innovation in design, among others.

Redwood Systems, a California-based provider of building-performance lighting solutions, has seen networked lighting work as the catalyst for optimal energy efficiency at data centers of all sizes. Redwood worked with social networking giant Facebook to install its lighting platform in its 300,000 square foot data center in Prineville, Oregon; this facility recently received LEED Gold certification. Since implementing the building-performance lighting system alongside other energy-saving measures as part of its Open Compute initiative, Facebook has realized 24 percent energy cost savings and 38 percent increased energy efficiency, creating a model for their forthcoming data centers.

For each of the above-mentioned customers, the lighting system was tailored to outfit that particular data center in the most productive, cost-effective and energy-efficient manner. A building-performance lighting platform like Redwood’s lends itself to complete customer control upon installation, and it adheres to flexible standards that allow for modifications to accommodate new features and grow with its owner for the foreseeable future.


When moving to greener data centers, organizations often overlook lighting technology as a way to improve energy efficiency. In fact, building-performance lighting systems can not only promote critical reductions in energy consumption but can also make facilities as a whole “smarter.” The key to improved building intelligence lies in integrated IT and building-performance systems. An intelligent LED lighting platform connects lighting with building operations ranging from temperature controls to occupancy sensing and security and to safety devices. The monitoring system, a component inherent to the lighting network, centralizes facilities management, providing easy, anytime web access to complete control panels for the buildings.

With the significant degree of insight intelligent lighting brings to data center management, organizations cannot afford to ignore lighting as they determine their energy-efficiency protocols in their data centers. In a world increasingly concerned with climate change and caring for the planet, compounded by tough economic times, a one-stop, comprehensive energy-efficient lighting solution that streamlines operations and cuts costs is an invaluable asset to data centers everywhere.

About the Author

Sam Klepper is EVP of Building Solutions and CMO for Redwood Systems. In this role Sam leads product and marketing strategy for the company’s building-performance solutions, which are optimized for energy efficiency in commercial buildings and data centers. He has more than 20 years of experience creating and marketing game-changing products in clean-tech and high-tech. Mr. Klepper has a B.A. magna cum laude from Harvard University and an M.B.A. from Harvard Business School.

About Jeff Clark

Jeff Clark is editor for the Data Center Journal. He holds a bachelor’s degree in physics from the University of Richmond, as well as master’s and doctorate degrees in electrical engineering from Virginia Tech. An author and aspiring renaissance man, his interests range from quantum mechanics and processor technology to drawing and philosophy.


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