Energy saving control projects
Energy usage is a major factor associated with manufacturing facilities. Tracking energy usage at the plant, production line, and equipment level can help monitor and reduce energy usage, saving valuable resources.
Imagine a production facility with zero downtime, no safety incidents, operators who operate at 100% capacity, and has enough orders to maintain maximum throughput. Where would a facility like this look for optimization? The first place would likely be reducing energy costs.
Although the facility like the one described above does not actually exist, understanding and reducing energy usage is a common practice at many facilities. Tracking energy usage can reduce direct costs for purchasing energy, improve equipment maintenance schedules, and integrate green energy and conservation initiatives to reduce a process' environmental footprint.
Track energy use, reduce costs
The first step to reduce energy costs is to understand energy usage. Depending on which types of energy a facility uses, this can take many forms. One of the most common scenarios is using electrical power meters capable of communicating energy usage information with a process control system. This data can be stored in a process historian to view electricity consumption over time, integrate with various products to understand usage metrics, or even correlate with billing information to reduce peak-demand usage. This information can be reported on a daily, weekly, or monthly schedule to help reduce costs where possible. Similar approaches can be taken with natural gas meters, steam and water flowmeters, and air systems.
Reducing energy costs and impacts
Once energy usage is being monitored, it can be compared with billing information to see if it is possible to reduce usage during peak demand times to save costs or compared with production information to see if it is possible to turn equipment off when not in use (or in standby mode for shorter periods) to reduce overall usage. If it is possible to change production schedules to work around peak demand usage times, a direct cost savings will be realized.
For example, a slot machine manufacturing company in northern Nevada implemented a process to reduce energy consumption. The process involved sending raw slot machine cabinets from a warehouse staging area to operator workstations at various points on the line. When an operator requests a machine, the conveyors turn on to bring the machine to the first radio-frequency identification (RFID) reader on the line. When it gets to a certain point, the next conveyor turns on, with subsequent checks turning on conveyors until the machine is at the final location. A timer is initiated with each RFID check, and the conveyors turn off when they aren't being used for 60 seconds to reduce energy consumption throughout the production line.
It might also be possible to negotiate rates with utility providers in situations where reducing usage during peak demand times cannot be avoided.
Energy as a maintenance indicator
Another way to reduce energy costs is by tracking current, overall energy usage over time compared to historical usage as a way to understand any lingering maintenance issues.
For example, if air usage over the past year has been fairly constant for different production scenarios, and it starts to increase without an associated change in production, there might be a leak in the system. The same process can be done with monitoring steam or natural gas. Electricity leakages may be more difficult to track down and can be compared with other data points from equipment to find the culprit. This approach should be in addition to current maintenance practices and not as a substitute.
Overall energy usage tracked at the plant level can also be used as a gauge against billing to ensure what is being used matches with what is being billed, which can lead to uncovering energy leakage throughout the plant.
Energy is one of the major costs involved for many manufacturing operations. Tracking energy use can lead to cost savings and can provide insight into the environmental impact of a facility. Tracking energy use may also assist in finding process optimizations and ways to reuse or recycle energy through the form of heat exchangers or mechanical systems.
Understanding energy usage and costs can provide the foundation for renewable energy projects using solar or wind energy to reduce a facility's overall dependence on utilities if the cost structure makes sense to invest in an energy-generation infrastructure.
Alex Marcy, P.E., is the owner and president of Corso Systems, a system integration firm, headquartered in Chicago Ill. Corso Systems is a CFE Media content partner. Edited by Emily Guenther, associate content manager, CFE Media, Control Engineering, firstname.lastname@example.org.
- Tracking energy usage for cost savings
- Energy usage to reduce a facility's environmental impact
- Understanding energy usage for process optimization.
How does tracking energy usage assist in process optimization at a facility?
See related Control Engineering pages on energy saving.
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