Use the maintenance function to achieve meaningful energy reduction
Our economic climate demands a renewed appreciation for continuous improvement methodology within maintenance organizations. As operating costs rise and profit margins shrink, it’s imperative that maintenance organizations focus on being a profit center and not merely a black hole from which capital returns never escape.
Maintenance organizations can achieve this by leveraging their team’s combined talents and experiences to foster an environment of world-class maintenance with a focus on energy conservation.
Many outside of the maintenance arena don’t understand that performing world-class preventive maintenance (PM) and predictive maintenance (PdM) provides more than just equipment reliability; it also helps to save energy, extend equipment life, reduce system downtime and increase the overall safety of the manufacturing facility.
Organizations that established holistic preventive and predictive maintenance programs find that total costs can be reduced by 40% to 50%. When we think of PM or PdM, we usually think of replacing worn parts such as filters, belts and couplings, as well as testing and refreshing lubricants. When maintenance technicians perform scheduled maintenance, they focus on a task list. Rarely will they venture deeper than instructed by the written word. Still, some technicians even possess the attitude that “close is good enough” when it comes to preventive maintenance. Have you heard any of these comments from your maintenance team after PM/PdM tasks are completed?
- “The V-belts looked fine, they’re a little glazed, but they’ll last another six months.”
- “The sheaves are almost aligned; no big deal, it’s pretty close.”
- “The steam trap has a small leak, but it can wait.”
- “I couldn’t find the right belt, but this one is close enough.”
- “The motor is running a little hot; no big deal.”
- “The motor trips every once in a while, so I put some extra fuses on the top of the box.”
- “The alignment of motor and pump is good enough.”
- “I ran out of grease, so I greased the front bearing; the other one looked alright.”
- “I just blew the air filter down with an air hose; it’s fine.”
While there are many facets to the world-class maintenance organization, they typically have one thing in common: world-class people. In short, the technicians and managers have the desire to be world-class. These professionals feel empowered and valued as important partners at their manufacturing facilities. Managers can help their teams become world-class by engaging them to be an instrument to facilitate energy savings. As maintenance personnel, they have a unique opportunity to make significant contributions to a company’s energy savings. Why? Because the technicians have a detailed understanding of the equipment’s functionality and the opportunity to make a difference.
Don’t let your team minimize its stature in the organization by telling you, “We’re just technicians.” How many CFOs or COOs can jumper a pressure indicator while a process is running or correctly torque a 300 plate titanium heat exchanger? None. That’s important because everyone needs to understand how much they contribute to a team’s success and to own it.
So, own it and challenge your team by tracking energy consumption trends. Many maintenance organizations employed and communicated process key performance indicators for years and they’ve become a valuable tool in managing complicated processes. Communicating energy consumption trends should receive the same visibility. Build a continuously updated dashboard (Figure 1) to communicate raw material and energy consumption and challenge your team to optimize their part of the energy conservation equation. In effect, empower your team with the information needed to succeed and help facilitate ownership of the process.
Figure 1. This dashboard display can spur a maintenance team to achieve significant energy reductions.
Many maintenance technicians tend to be competitive people. You can see that characteristic reflected in their personal lives. Their free time is consumed by pursuing their passions, family time or hobbies, as they strive to be the absolute best in their areas of interest. For example, technicians who are hunters spend countless hours in the woods scoping out trails and trees for the ideal place to put a tree stand. Then, there are the fishermen, always looking for the latest and greatest fishing lure or secret fishing spot. These folks are passionate and talented individuals, and it’s essential for managers to tap into this passion at the workplace to develop their world-class maintenance organizations.
It can’t be overstated that poor preventive maintenance practices cost manufacturing firms billions of dollars a year in wasted energy and production downtime. In the United States, energy costs often are upward of 25% of a manufacturing facility’s total operating cost. For example, energy accounts for 43% of a petroleum refinery’s operating cost. In steel manufacturing, energy makes up 15% to 20% of the cost of production. Electricity constitutes 30% of total production cost for manufacturing aluminum. With staggering figures like these, it’s not enough to confirm that equipment is running merely by checking filters and V-belts. Every aspect of the equipment must be scrutinized to ensure it’s being maintained as intended and operating as efficiently as possible. Moreover, we also need to consider how we can improve maintenance each time we put our hands on the equipment.
A well-thought-out preventive maintenance task list is a valuable tool for developing a world-class preventive maintenance program that focuses on continuous improvement. Task lists should be consistent and developed on the basis of input and suggestions from technicians. Maintenance supervisors should initiate constructive discussions with technicians to review every PM/PdM.
Some discussion points might include any number of questions.
- Is the lockout/tagout procedure complete? How can it be improved?
- Did you inspect the equipment while it was running to document operating temperature, unusual noises, leaks, vibration, operating pressures and other system variables?
- Did you receive the equipment on time?
- Did you discover anything out of the ordinary?
- Was the equipment restarted correctly after the PM was completed?
- Are there any conditions or changes that could improve the equipment’s performance?
Ensure that each item on your final task list has a check box in which the technician enters a mark to signify task completion.
[pullquote]Support your team by introducing an overall strategy to reduce energy consumption through a management system that measures progress and drives continuous improvement. As your team makes improvements, celebrate your victories and track them on a benefit-tracking spreadsheet. You and your team can communicate your accomplishments annually during your company’s performance review cycle. Meet with your team regularly to discuss progress and compare it to similar plant areas or other well-established benchmarks to encourage healthy competition.
Achieving energy efficiency and sustainability depends on evaluating your strategy effectively and reviewing and assessing the process continuously. Performance evaluations are intended to:
- Track, monitor and report on progress
- Reinforce the use of measures that identify opportunities to support goals and improve on performance
- Invite input and provide constructive feedback
- Inform about energy consumption, progress toward goals and the effect of one’s actions.
Furthermore, assist your organization by establishing an energy management team (EMT), a cross-functional panel comprised of personnel from operations, maintenance and engineering, charged with identifying opportunities in energy conservation. Engagement of senior management will be essential to ensure the effectiveness of the EMT initiatives.
The EMT facilitates implementation of an overall strategy through coordination, communication and guidance. The team members’ role is to contribute their expertise, communicate current information and exhibit a solid commitment to meet the objectives listed in the team’s charter. Establish monthly team meetings to provide opportunities to communicate, define and improve processes; review goals; and allow feedback for improvement. So, how much can world-class PM and PdM programs save the bottom line?
Belt drives: If slippage occurs because the belt isn’t periodically re-tensioned, efficiency deteriorates over time by as much as 5% to a nominal 93%. V-belts can be replaced by cogged belts, which reduce the bending resistance, run cooler, last longer and have an efficiency about 2% higher than that of standard V-belts while using the same pulleys.
A continuously operating, 100-hp, supply-air fan motor (93% efficient) operates at an average load of 75% while consuming 527,000 kWh annually. Electricity is priced at $0.05/kWh. What are the annual energy and dollar savings if a 93% efficient V-belt is replaced with a 98% efficient synchronous belt?
Energy savings = Annual energy use x (1 – 0.93/0.98)
= 527,000 kWh/year x (1 – 0.93/0.98)
= 26,888 kWh/yr
Annual cost savings = 26,888 kWh x $0.05/kWh = $1,345
HVAC: The important thing to remember about poorly maintained HVAC systems is that they can go unnoticed until it fails because thermostat setpoints try to maintain unvarying system conditions. Proper PM on HVAC units can save as much as 20% on energy costs. Freon undercharge of only 10% can increase operating costs by as much as 20%. A dirty evaporator, condenser or blower wheel could increase electrical consumption by 50% or more. A mere 0.01 in. of dirt or film on an evaporator coil can reduce efficiency by as much as 15%.
Lubrication: Research suggests that improved lubrication and the consequent friction reduction in gear sets can result in energy savings of as much as 15%. Benefits can accumulate from fuel savings as well as a reduction in carbon emissions. Changing from a monograde hydraulic fluid to a multigrade, or high-viscosity index fluid, has the potential to improve overall efficiency or reduce energy consumption by up to 25%.
Steam traps: Facilities with no active steam trap PM/PdM program might have 50% of the traps blowing steam. A trap with a 3/32-in. orifice operating at 100 psi can lose almost 30 lb of steam per hour. At $8/1,000 lb of steam, that can result in a loss of more than $2,000 a year from each faulty trap of that type.
In a system of 1,000 steam traps, it’s assumed that the average orifice size of a blow-through is 1/16 in., the average pressure is 150 psig and the cost of steam production is $4/1,000 lb. It’s also assumed that the plant steam is in operation 365 days/year, 24 hours/day. Based on these assumptions, the steam loss per day is 453 lb per trap at a cost of $1.81/day/trap or $662.25/year loss per trap. A conservative assumption that only 10% of the traps are faulty would result in an annual cost of $66,225 in lost steam within the system.
- DOE/GO-102000-0988 (Dec 2000)
- DOE/GO-102005-2060 (Sept 2005)
- Engineering News, South African Institute of Tribology (SAIT) Swan (Jan 2008)
- Intermediate Energy Handbook, Energy Consumption, The Need Project, 2008
- Thomas Net News, Reducing Energy Consumption and Cost, Fontelera (June 2009)
Compressed air: Approximately 70% of plants use a compressed air system to power machine tools, material handling equipment, separation equipment and spray painting equipment. Energy audits the U.S. Department of Energy (DOE) conducted suggest that more than 50% of compressed air systems at small- to medium-sized industrial facilities have low-cost energy conservation opportunities.
A chemical plant undertook a leak prevention program following a compressed air audit. The program found 100 leaks of 1/32 in. at 90 psig, 50 leaks of 1/16 in. at 90 psig and 10 leaks of 1/4 in. at 100 psig. Assuming 7,000 annual operating hours, an aggregate electric rate of $0.05/kWh and compressed air generation requirement of approximately 18 kW/100 cfm, the annual cost savings attributable to leak elimination would be in excess of $57,000, with the 10 leaks of 1/4 in. account for almost 70% of that total.
Establish solid foundations for progress by investing time to effect positive change.
- Focus a portion of your available PM/PdM manpower to correct/repair water, air and steam leaks.
- Develop a leak-tagging process that identifies and rates leaks by severity to ensure the right work is being performed at the right time.
- Convert V-belt drives to cogged belts.
- Balance HVAC equipment to ensure optimized system performance.
- Equip and train your team to use energy-saving tools such as air flow hoods, ultrasonic leak detectors, infrared thermography, belt tensioning gages, sheave alignment tools, laser alignment tools and CMMS software.
We’ve all seen the “flavor of the day” initiatives that come down the corporate pike. Don’t let nonproductive cynicism stop you. It’s important to control your own destiny by controlling every element of your maintenance process, including energy cost. Don’t wait for a corporate directive to take action. Do it now. Furthermore, you might be able to secure additional help from government grant money to accelerate your energy saving programs. Lead the way for your team with passion and by developing a sense of urgency for your team to identify with success and your world-class technicians will follow.
Dan Towse, CMRP, is senior consultant at T.A. Cook in Raleigh, North Carolina. Contact him at [email protected] and (646) 596-2473.