In many companies, there’s a push to save energy by replacing existing lighting with LED equivalents. Although that’s not a bad idea, it would be better to rethink the entire lighting scheme so that you can make full use of what LED systems can offer. This requires some legwork, but it’s worthwhile.
Be aware that a focus on going to LED may leave considerable energy savings unrealized. Plus, you have to factor in the costs of installation and (likely) disruption of work for replacing one lighting system with another. The costs and disruptions are almost certain to be worth it, but you may achieve other energy savings at probably lower cost and probably with little or no disruption.
Here are a few other areas where you should direct some attention:
Motor vibration — What’s really going on when a motor vibrates? Energy is being converted into motion. If the mass of the motor is moving half an inch back and forth 100 times per minute, how much energy does it take to do that mechanical work?
Fixing this problem gives you respectable energy savings while reducing wear on the motor system and whatever it’s coupled to. Conduct vibration analysis on all of your motors, starting with the largest ones. For critical motors and your largest ones, seriously consider installing vibration monitoring. If you already have vibration monitoring, who is monitoring the monitor and what action is being taken?
Power factor — A common misconception is that installing power factor (PF) correction capacitors at the service entrance saves you energy. What it does at this point of installation is reduce or eliminate the PF penalty that the utility might levy. To save energy, you need to install PF correction at the load. For example, install PF capacitors at your largest motors; if any have an electronic drive, contact the drive manufacturer for advice.
Supply losses — You want to get power from the source of supply to the load with the lowest losses you can reasonably ensure. Losses may exist in the conductors and at connection/termination points. For the conductors, start with voltage drop calculations. Upsize any long runs as needed. Then review your cable testing program to see if it’s adequate. If you don’t have one, establish it. If a plant has been operating for several years (or more) without a cable testing program, it’s often a real jaw-dropper to see just how bad the cables are. At the very least, your feeders should be on an insulation resistance testing program.
A thermographic inspection program that includes all accessible connections and terminations is a cost-effective way to detect losses at these points. Conducting AC resistance testing across made connections can tell you just how bad a connection is; use that figure to calculate the energy losses across the connection (how many watts it’s costing you). Bolted connections are best repaired not by merely tightening them, but by disassembling them, cleaning them, reassembling them with new hardware, and tightening them to the specified torque.
