MRO Magazine

Green maintenance: 7 steps to achieve energy savings


Industry

March 1, 2010
By PEM Magazine

Where does a company begin to create an energy efficiency strategy? It should start with a program that includes objectives of reducing energy consumption while increasing energy efficiency. As part of the strategy, there needs to be a straightforward method to measure both components to the strategy. It’s a well known management principle that you can’t manage what you don’t measure.

The seven steps to starting an energy efficiency program include:

1. Identify most energy intensive assets (equipment/systems).
2. Develop an energy profile.
3. Take measurements based on profile.
4. Review trending for opportunities (analyze).
5. Report and discuss opportunities with managers.
6. Create or adjust preventive maintenance (PM) and predictive maintenance (PdM) programs from analyses:
• Identifying opportunities from normal inspections should also be considered.
• Heating, leaking and wearing should be signs of energy loss that are given a higher priority for conservation-sake.
7. Propose capital investments from prioritized opportunities.

Step 1. Identify most energy intensive assets.
Generally most companies don’t monitor energy usage on an equipment basis. It may be worth considering installing monitoring devices if it’s cost effective. Another option would be for a technician to take periodic measurements, for an example, an electrical current, which can be used in conjunction with operating hours of the machine. A calculation can be derived to estimate electrical usage that could be reconciled with the electrical bill on a monthly basis to prove accuracy.

Equipment (i.e. motors, drives, compressors and boilers) would all fall under the category of energy intensive as would systems, such as heating, ventilation and air conditioning (HVAC), refrigeration and ovens.

Step 2. Develop an energy profile.
From the manufacturer’s specifications, an equipment or system is rated for a certain amount of energy usage. These specifications would be a baseline to compare the measurement readings for the initial efficiency ratings. The energy profile may also contain specification data, which would be helpful in comparing design issues. This data will also be useful in designing programs for inspections, meter readings, PM and PdM plans.

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Step 3. Take measurements based on energy profile.
In this step, we need to develop a method for taking and collecting measurements for the equipment. A determination will need to be made as to who is qualified for taking the measurements. If there are monitoring devices on the equipment, can the operators take the readings? If there are no monitoring devices, what will the method be to take the measurement to ensure consistency?

Step 4. Analyze trending for opportunities.
The trends from the measurements may show opportunities, such as spikes in the usage, heating or leaking issues, and other opportunities, which if addressed, could result in a cost savings. This point is extremely important for maintenance organizations. Consider the savings that companies have realized from: air and steam leak reduction programs, as well as energy efficient motor replacements/specifications.

Step 5. Report and discuss opportunities with managers.
Once the data has been collected and analyzed, communicating with management is essential in capitalizing on the opportunities that were discovered. In some cases, large reductions in energy costs can be obtained by a small change to the production schedule. Managers in the company would benefit from this information and can participate in the company’s green savings. In addition, other policies and practices may be uncovered that will have potential energy savings.

Step 6. Create or adjust PM and PdM programs from findings in step 4.
Once data from the energy measurements has been collected, detailed reporting will be developed that will highlight emerging gaps in the existing PM and PdM programs. Additional job tasks or inspections may be needed to maximize energy savings, and also allow minor issues discovered in the analysis to be addressed early and prevent larger problems from occurring or recurring. This option is very low cost and can be implemented immediately with minimal training and practically no capital investment. Enlarging on some maintenance-specific opportunities, proper lubrication levels would fall into this category. If a bearing has too much or too little lubrication, it will take additional energy to rotate the bearing. Multiply this small amount of energy times the number of bearings that are in operation in the plant and the potential savings grow exponentially.

Additionally, consider the energy losses due to improper coupling alignment. Some organizations make an initial evaluation of a coupling’s condition by a thermography image. If the temperature is elevated, it indicates misalignment of the coupling. The excess temperature rise is another source of wasted energy.

The same can be true of V-belts. A V-belt can slip up to 20 percent of its rated load before it begins to make noise. A company could reduce energy waste significantly by using a thermography inspection of the belts and sheaves. Even a strobe light inspection to check for slippage can produce a significant return on investment.

The space isn’t available in this article to explore all of the potential areas of maintenance savings. However, briefly mentioning properly cleaned and tuned HVAC systems, properly tuned boilers, properly maintained building envelopes, heat exchangers and coolers cleaned at the proper frequencies, allows any company some starting ideas. Developing good preventive and predictive practices in these (and other) areas will show significant green benefits.

Step 7. Propose capital investments from identified opportunities.
For larger projects, such as equipment replacements, overhauls, or investing in newer technology (i.e. solar, wind and geothermal energy solutions)—it’s necessary to review this list of suggested opportunities with an open mind and eye on the overall energy efficiency strategy.

If replacing 20 and 30 year-old compressors with newer more energy efficient ones that promise to be 70 percent more efficient—a cost analysis comparing maintenance costs on the older equipment with the cost of purchasing the newer compressors factoring in the energy savings as part of the life cycle costs would definitely be worth the effort.

This is an edited article provided by Vesta Partners LLC. Tony Buffington is consultant (SAP Certified Associate). You can contact him by email: tbuffington@vestapartners.com. Terry Wireman is senior vice-president. You can contact him by email: twireman@vestapartners.com.