White Paper

Innovative Data Center Lighting Solutions Deliver up to 90 percent energy cost savings

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Innovative Data Center Lighting Solutions Deliver up to 90 percent energy cost savings

Data center managers are under more pressure than ever to improve energy efficiency and lower total cost. One promising opportunity is in the choice of lighting. Although it accounts for just 5% of a data center’s typical energy budget, lighting offers a key advantage in that it is not part of the critical IT path. This makes it much easier to make changes without gambling with up-time performance.

A simple change in color yields savingsOne innovative approach that’s been generating a lot of excitement and discussion is the use of white cabinets in the data center. Some studies have found that the increased reflection inherent in white surfaces can save 20 percent or more on lighting costs.

Our own study confirmed these savings, revealing that white cabinet surfaces combined with white floor surfaces reduce the number of necessary light fixtures by 22 percent.

Optimizing the lighting platformAs impressive as these initial savings are, even greater savings are possible by optimizing the lighting platform itself. In fact, by focusing on these capabilities, savings based on controlling the lighting in the data center can exceed 90 percent. Such optimization opportunities include:

• Upgrading to LED technology, which is far more energy-efficient and has a longer operating lifetime than traditional fluorescent technology. The cost benefits are twofold: less power consumed for lighting, and reduced cooling requirements due to LED’s lower operating temperature.

• Deploying an intelligent, high-density sensor network that can adjust lighting based on conditions such as occupancy, motion, or pre-set policies to vastly reduce wasted lighting energy.

• Powering the LED lighting with low-voltage direct current (DC), which can be done over structured cabling. This makes any changes much simpler, less costly and less disruptive than using traditional alternating current (AC) mains power.

This paper will provide details on the results of the study in moving to white cabinets. It will also explore the substantial additional savings via use of the intelligent, optimized LED lighting platform outlined above.

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Lighting design in the data centerAs part of the overall data center planning process, a lighting engineer provides a design which ensures that sufficient light is provided in all areas of the data center, based on each area’s needs. For instance, technicians working on equipment within a cabinet require a greater level of light than that required for security cameras in unoccupied areas.

For objective measurement, these lighting values are expressed in foot-candles, or in the metric unit of lux. One foot-candle is equal to approximately 10 lux.

While there currently are no published standards defining minimum light levels in a data center, the document TIA 942-A (Telecommunications Infrastructure Standard for Data Centers) does contain an informative annex that recommends an ascending three-level lighting approach:

• Level 1 to provide sufficient light for surveillance cameras in an unoccupied zone

• Level 2 to provide enough light for personnel to safely navigate, with use of motion detectors to minimize light when unoccupied

• Level 3 to provide sufficient light for working on cabling or equipment

The IESNA (Illuminating Engineering Society of North America) is also referenced; however, they do not have specific guidelines for data centers.

Case Study: Moving from traditional black to white cabinetsPart of the lighting engineer’s work is to model the illuminance delivered in the data center based on the cabinet layout, fixture height, and surface reflectance. As part of this study, we modeled a data center with 10.4m2 of white space consisting of 20 server cabinet rows, two rows of cabling connectivity and various CRAHs (Computer Room Air Handlers) and Power Distribution Units (PDUs) at the ends of the server cabinet rows.

Per the following floor layout, a total of 245 lighting fixtures were required when using industry-standard black cabinets and grey floor tiles.

Innovative Data Center Lighting Solutions Deliver up to 90 percent energy cost savings

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Innovative Data Center Lighting Solutions Deliver up to 90 percent energy cost savings

These models were based on the following reflectance values:

Based on the use of white cabinets and floor tiles in this model with all other factors unchanged, the number of light fixtures required while still providing the equivalent foot-candle value was reduced to 202, which represents a 22 percent savings in both hardware and energy costs.

Criteria Model 1 Model 2

Top of Cabinet 20% 85%

Bottom of cabinet 20% 85%

Sides and Frames of Cabinets 20% 85%

Reflectance of Floor 20% 80%

Additional measures to reduce data center lighting costsWhile the move to white cabinets and its corresponding reduction in the number of required fixtures is impressive, even more substantial improvements can be made in reducing the overall power budget for data center lighting.

The first logical step is to consider the technology used in the lighting elements themselves. Traditional fluorescent lights can be replaced with LED lights, which use less power to operate. This delivers two main benefits:

• Lower operating expense due to reduced energy demand

• Lower cooling costs for the data center due to lower operating temperatures LEDs provide at the same level of lighting

Additionally, LEDs provide more efficient dimming control, increasing the flexibility to adjust to changing conditions and requirements. For example, the lighting above a row of server cabinets can turn itself off whenever data center staff are not present, and turn on when it detects someone in the area. This is possible thanks to a network of low-cost sensors that can detect not only the level of light, but also motion in the room.

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Innovative Data Center Lighting Solutions Deliver up to 90 percent energy cost savings

As shown above, light fixtures can be provided with integrated sensors, allowing for high-precision tuning to match lighting requirements with occupancy.

Along with this high-density sensor network, policies can be set to match lighting levels for different areas in the data center, in accordance with the recommendations published in document TIA 942-A. For example, lower lighting levels are suitable for areas where IP security cameras are located. Medium lighting levels are suited to areas where personnel traverse the data center and need to navigate spaces safely. Higher lighting levels are ideal where technicians are working on equipment or cabling. But even beyond these general guidelines, additional savings are possible as the ability to fine-tune these levels presents not just three options, but dozens.

Other benefits of moving to LED technology include much longer operating life than fluorescents, which means reduced maintenance expense and less disruption in the most critical areas in the data center.

LED lighting and structured cablingA side benefit to the reduced power demand of LED systems is the ability to power them over structured cabling rather than the traditional AC mains cabling. This advantage is particularly valuable in a data center environment, where frequent changes and technology refreshes can benefit from easier-to-handle structured cabling for lighting power. When cabinet configurations or locations change, it’s much easier and faster to reconfigure the lighting to adapt to changing needs.

SummaryIndustry studies, including our own, have shown that the use of white cabinets in place of the industry standard black design can reduce the number of required lighting fixtures by 20% or more, depending on the physical layout of the equipment cabinets. While this has the benefit of reducing capital expense, much more significant energy savings can be realized by utilizing a sensor based LED lighting platform that can adapt to different lighting needs throughout the data center. In addition, the ability to power LED systems over structure cabling helps expedite and simplify the inevitable changes in a data center’s layout.

Sensor integrated in fixture (courtesy of Richter Lighting Technologies GmbH

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All trademarks identified by ® or ™ are registered trademarks or trademarks, respectively, of CommScope, Inc. This document is for planning purposes only and is not intended to modify or supplement any specifications or warranties relating to CommScope products or services.

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