New approaches to asset management yield big energy savings
Intelligent use of control systems can maximize the energy efficiency of industrial equipment by, among other things, making sure equipment runs only when need to support plant operations.
There's widespread evidence—in the form of numerous analyst reports, articles, and case studies-that industrial companies have made great strides at becoming more energy efficient in recent years.
There's also ample evidence that there's still much room for improvement.
The manner in which most manufacturers approach energy management remains the greatest barrier to maximizing energy efficiency. The typical approach is to launch one or more small projects that produce a quick-and sometimes even substantial-return on a relatively small investment.
However, once these quick-ROI projects are completed, manufacturers often have trouble finding additional ways of improving energy efficiency.
Often, this is because management doesn't believe energy management projects can have the same impact on the corporate bottom line as finely tuned production processes or well-orchestrated customer acquisition strategies.
This belief also stems from the way most industrial companies approach energy management. Experience has shown that energy performance gains from various one-off energy management projects do not deliver sustained energy performance improvements, particularly if those projects are not monitored and adjusted in a continuous manner.
To ensure sustained energy performance gains, energy should not be considered a fixed operational expense. It must be managed just as carefully as production, quality, and safety. To do so requires the collecting of quantifiable energy performance data.
In a 2012 global survey conducted by Deloitte LLP, only 12% of chief financial officers chose the word "excellent" when asked to rate the quality of the sustainability data they normally receive. Industrial companies could benefit from the implementation of data-driven business practices that will result in continual energy performance improvements.
Establishing key energy-performance indicators
The best approach to reducing your energy expense and use is to take a holistic view of your energy portfolio. This is typically best done by having an independent energy-engineering firm review your energy portfolio. The energy-engineering firm will want to review all of your facilities and determine the key energy performance indicators (KEPIs) that drive energy use. These KEPIs may be different at each facility depending on what industrial process is performed at each facility.
To ensure sustained energy performance gains, energy should not be considered a fixed operational expense. It must be managed just as carefully as production, quality, and safety.
Each facility should have accurate energy cost and use data for each commodity that is utilized at the facility. This information will determine which facility should be addressed first. Typically, one would start where both use and cost are the highest, which leads to energy projects that will yield the largest saving opportunities in the least amount of time.
Once a facility has been identified as a viable candidate for an energy management project, the following steps can be taken:
- A preliminary facility assessment to determine energy-saving opportunities
- Energy project development with associated return on investment calculations
- Project approval and funding
- Project implementation
- Project measurement and verification.
The controls arena offers many opportunities for reducing energy consumption in industrial facilities. These opportunities cover typical major pieces of equipment that exist in s various industrial environments. These include compressed air systems, boilers, refrigeration compressors, chillers, lighting systems, pumping systems, and more. In many of these systems, the purpose of the control system is to limit the operation of the equipment to run only when it is needed and to maximize the load on equipment when it is used.
A master system controller can be used to stage multiple compressors in complex systems. Strategic pressure sensors are deployed in the distribution headers and used to provide feedback to the control system. The pressure readings, along with the rate of change of the pressure readings, are used to select which compressors should run to meet the load and, in some cases, what the loading should be on the compressors.
The same concept of properly controlling multiple air compressors can be carried over to other compressor applications. These include chillers (where the compressors are trying to maintain a constant supply temperature) and refrigeration compressors (where the compressors are trying to maintain a constant suction pressure). In all of these cases, a master system controller can maximize the efficiency of the units by minimizing the number of partially loaded compressors.