Lighting Efficiency Series: Stretching the savings
Everyone is always saying the best way to save energy is to turn off your lights and equipment when they are not being used. It is a simple concept but not so easy to put into practice. It requires a cultural change that is hard to implement and even harder to maintain.
July 13, 2009 By Greg Jones
On a recent trip to visit production facilities in China, I was impressed to see this approach being implemented on a regular basis. When the lunch bell sounded it was the responsibility of one person to turn off all power to the plant — lights and motors! Even though the lighting was quite new and very efficient the energy savings from this action were still deemed important enough to assign this task. This procedure is easy to implement in China, where they often have abundant low cost labour.
In North America, we all know the situation is very different. Plant personnel normally have many more important tasks to complete, and turning off the lights is not seen as a priority. Over the years, many companies have tried to implement cultural change with training and strategically placed stickers on switches. Usually, after some initial enthusiasm, the program falters and is eventually abandoned.
Fortunately, the market now has a wide range of reliable, low cost equipment that can automate this process. There is no longer a need to worry about behavioral change or assigning dedicated staff to the problem. The primary options include devices such as:
- Motion sensors – These devices have long been used in applications such as washrooms where use is infrequent. Now they have become so cost effective that they are being used on individual fixtures in applications such as warehouses. The main aisles may be lit all the time but side aisles are typically controlled by sensors.
- Photocell sensors – Light fixtures near doors and windows normally don’t contribute much to the light level during daylight hours. A photocell sensor can turn the fixture off until nighttime or a very cloudy day requires their use.
- Dimming ballasts – Fluorescent fixtures can use dimming ballasts to provide small adjustments in light level. They can be used in any lighting circuit to allow the light level and the energy use to be adjusted as required. They are often used in conjunction with photocells to achieve “daylight harvesting”.
- Controls – The range of control devices available today provides a solution for every application. The most basic control is a simple switch for sensors and ballasts that can be connected by wire or using wireless components where running wires is difficult. Time clocks can be integrated to allow full scheduling of equipment. More sophisticated computer controlled systems allow full optimization. Some systems use a central computer to manage all the scheduling, sensors and even address individual ballasts. Other systems allow the central computer to connect to a LAN system that can be accessed by any staff member with a password. With this technology, it is possible to allow individual office staff to adjust the light level over their desks.
At Nexstar Lighting, we evaluate the cost and benefit of using controls and sensors on each project to ensure we fully optimize our client’s investment.
Greg Jones (email@example.com) is President of Nexstar Lighting.
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