Smart lighting systems reduce plant energy consumption

Illuminating the steps to an upgrade

March 1, 2010

Updating and upgrading your facility’s lighting system is an excellent way to cut costs and reduce your company’s carbon footprint. Using controls and sensors, lighting management systems can reduce building lighting consumption by the timely eliminating of usage in off-peak periods with little or no effort by building managers.The six steps to completing a lighting upgrade are audit, system design, installation, programming, operation, and maintenance. Each layer of savings (upgraded lamps, ballasts, fixtures, and controls) should improve your payback.

Updating and upgrading your facility’s lighting system is an excellent way to cut costs and reduce your company’s carbon footprint. In your efforts to reduce energy consumption, and associated costs, by revamping your lighting system, be sure to do so without compromising occupant safety, employee morale, and productivity levels.

Also, when making plans to implement a more energy-efficient lighting system, avoid falling into the trap of updating each and every component of the system. Some changes may not be necessary or advantageous to the staff, facility, or the bottom line.

Conduct a Lighting System Audit

1. Select an Expert Consultant. The first step in making a lighting upgrade is to find a knowledgeable, qualified expert to conduct a full analysis of the current facility. This step is one of the most important, because your expert will make recommendations and guide your purchasing decisions.

   Often your local electrical energy provider offers this service free of charge and will provide an unbiased recommendation. The utility company may offer to provide records of your facility’s lighting energy usage, which will help isolate which areas consume the greatest amount of lighting energy.

   Expert assistance is also available from performance contractors and energy service providers, which may be able to provide the facility with a turnkey solution.

2. Inventory System Components. Conduct a full inventory and analysis of all existing components of your lighting system and their usage—from the lamps, fixtures, and ballasts to the sensors and controls used to govern them. By conducting this inventory, you will be able to focus your upgrades on the areas that will benefit the most and maximize your savings.

Auditors should record where all existing controls are located, including the system’s switches, contactors, sensors, and time clocks, as well as how they’re managed – either through scheduling or local occupancy switching. Equally important are the strategies that these controls utilize.

1. Assess Lighting Levels. Perform a review of the actual light levels for the floor plan. In work areas, record both the horizontal and vertical luminance (or footcandle) measurements of the work surfaces and floors. Professional guides, such as the Illuminating Engineering Society’s Lighting Industrial Facilities guide (RP-7-01), can provide guidance and best practices for proper footcandle measurements in different types of buildings.

1. Monitor Space for Activity, Natural Light Availability. Many control manufacturers and utilities offer data loggers that can be deployed in occupied spaces to determine real occupancy rates, artificial light usage, and natural light levels. The software estimates where energy can be saved by switching lights off automatically when areas are vacant, or during periods when natural daylight is adequate.

Based on the audit, prioritize your attack plan and budget for upgrades. Upgraded lamps, ballasts, fixtures, and controls can add layers of energy savings. Armed with estimated energy savings for each layer, you can match your budget and timeline to your total cost of ownership (TCO) goals. The TCO should be lowest when you choose the longest-life lamps, the most efficient fixtures, the most efficient ballasts, and the most aggressive controls.

With careful selection, you could save more than 10 watts per fixture.

Take Control of Efficiency

The most efficient light is one that is off. Today’s generation of lighting controls squeeze out the last bit of savings by switching lighting circuits on or off based on occupancy, and by dimming fixtures when enough natural light is available.

Updated “Smart” Controls. Older smart systems frequently misbehaved and either irritated occupants or did not save energy as expected. Updated smart controls use integrated sensors to receive information about the light conditions around them, and through daylight-harvesting algorithms, subtly adjust the artificial light levels throughout the day to best accommodate the needs of the space and its occupants.

Access Incentives. You may be able to capitalize on utility programs that incentivize customers to participate in demand response programs through one-time rebates or special participation electrical rates. Utilities also encourage their largest customers to reduce peak demand through peak shaving, or the effort to reduce usage during peak demand periods. Lighting management systems can reduce your building’s demand charge, or the higher rate you pay during peak demand, by the timely reduction of peak usage—with little or no impact on the occupants.

A smart lighting system has the following components:

1. Local control inputs—light and occupancy sensors, wall switches and dimmers: These components are the eyes and ears of the system. Proper placement of sensors is crucial for trouble-free performance. Also, unexpected energy savings and productivity gains can be achieved by allowing occupants personal control over their light levels using local dimmer switches.

2. Control outputs—AC relays and dimming blocks: These components are the fingers and toes of the system. To save energy, lighting controls need to interrupt the circuit or provide a dimming signal to the light source.

3. Efficient, controllable, light sources: Manufacturers are the most receptive to aggressive energy saving controls when they don’t notice when the energy savings measures are engaged. Good systems switch lights off; better systems switch lights between distinct light levels, and the best systems provide smooth dimming control between light levels. Use the advice of your consultant to choose the best control scheme you can afford.

4. Local automation: For many applications, a stand-alone occupancy sensor is all that is needed. These typically include the intelligence and AC relay required for autonomous operation of a few fixtures. For more complex situations, a room controller is needed to automate multiple circuits or provide daylight harvesting for a collection of fixtures.

5. Link between zones to form a network for whole-system automation: Today’s most aggressive smart controls link together in easy-to-wire, low-voltage networks that share sensors and optimize the system across many zones. With multiple zones under common control, building owners can link forces with the local utility’s smart grid programs to reduce electrical demand during peak utility rate periods—even on short notice. Some projects can be fully justified through the savings from the reduced utility demand charge.

Upgrade Steps

A typical lighting control facilities upgrade includes the following steps:

1. Audit, including data logging, light level review (consultant)
2. System design and quote (electrical engineer)
3. Installation (electrical contractor)
4. Programming/system tuning (electrical engineer)
5. Operation (building operator)
6. Maintenance (electrical contractor;  periodic visits from the electrical engineer for tuning)

Expect Reasonable Payback

Each layer of improvements (upgraded lamps, ballasts, fixtures, and controls) should shorten your payback time. Most of these layers will net savings if your facility hasn’t had a lighting upgrade within the past eight years.

In many plants where occupancy is not constant or good natural daylight levels are available, smart control upgrades can have a short payback period of two or three years. Also, do not forget that your utility partner may have incentive money available to discount the purchase price of efficient NEMA Premium® ballasts and sensors.

To read success stories about smart lighting systems for different industries, refer to the EPA Industrial Energy Management Information Center Web site.

Consider Certification

While upgrading your building, you may want to consider applying for certification with energy-efficiency organizations. The U.S. Green Building Council’s (USGBC) LEED® for Existing Buildings: Operations and Maintenance and the EPA’s Energy Star program are two of the most prominent and prestigious certifications that are awarded for energy-efficient buildings and may allow you to earn additional tax savings.