Small- and medium-sized Tennessee manufacturers across virtually every industry strive to reduce energy consumption while maintaining peak production and profitability, yet it’s not always easy. Fortunately, help is readily available through the Tennessee Tech University Industrial Assessment Center (TTU-IAC).
Students of Tennessee Tech University examine equipment at a manufacturing plant as part of the school’s Industrial Assessment Center program.
Launched in 2006, the TTU-IAC program provides manufacturers in the state with free energy, productivity, and waste assessments – including best practices for compressed air systems, and blowers and vacuum, as well as cooling towers and chillers. The assessments to date have provided manufacturers in the program with \$27.48 million in recommended cost savings, equaling 3.82 trillion British thermal units of energy savings.
Tennessee Tech University Industrial Assessment Center Program Director Dr. Glenn Cunningham, P.E.
The initiative is a win for both manufacturers and engineering students who make sustainability and cost-efficiencies in manufacturing a priority, said TTU-IAC Program Director Dr. Glenn Cunningham, P.E.
“The program gives our students real-world experience in manufacturing and really opens their eyes about energy costs and the potential savings,” Cunningham said. “At the same time, manufacturers appreciate the assistance and opportunities to save energy.”
Typical Savings of \$100,000 Per Year Identified
Manufacturers in Tennessee eligible to take advantage of the free IAC assessments must be a U.S. company with yearly energy bills greater than \$100,000 and less than \$2.5 million and be located within 150 miles of an IAC center. The two centers in the state include the Tennessee Tech University in Cookeville, Tennessee, and the University of Memphis, managed by Dr. Jeffrey Marchetta.
Each year, TTU-IAC evaluates applications for assessments from companies throughout Tennessee, as well as the surrounding states. It then works with companies to implement the assessment process, which primarily includes:
- The completion of a pre-assessment form to gather basic information about the plant, including a year’s worth of utility bills.
- A pre-assessment analysis of the manufacturing processes and utility bills.
- The assessment itself, which involves a one- or two-day onsite visit at each plant to refine the list of energy-saving opportunities and gather more data.
- A report outlining recommendations regarding best practices and individual energy-saving recommendations.
- Follow-up discussions after two weeks, and again six to nine months after recommendations have been submitted as a check-up and to answer questions.
The national IAC program was originally created by the Department of Commerce in 1976 in response to the oil embargo and rising energy costs. Since then, it has been specifically focused on helping small- and medium-sized manufacturing plants reduce unnecessary costs from inefficient energy use.
The federal program is administered nationally through the Advanced Manufacturing Office under the Office of Energy Efficiency and Renewable Energy at the Department of Energy. Each year, 13 to 14 undergraduate and graduate engineering students participate in the program and annually complete a total of 18 assessments.
Since the program started, TTU-IACs have conducted 221 assessments and provided assessment reports to 180 manufacturers. The average assessment identifies more than \$100,000 in energy savings opportunities. Assessments involve all plant systems and utilities, including compressed air, steam, process heating and cooling, HVAC, lighting and more.
Students Learn Invaluable Real-World Experience
The program provides incentives to students interested in a career associated with manufacturing and energy savings. In Tennessee, the program pays undergraduate students an hourly wage to participate. Graduate students earn two years of college tuition and a monthly stipend.
Students gain real world experience while participating in the Tennessee Tech University Industrial Assessment Center program.
Importantly, students who complete the program earn a certificate in energy assessment expertise. The educational and real-world experience combined also provide a solid foundation for a career in manufacturing, which includes roles as energy managers.
“The program provides insight for students into how energy is bought and sold, and consumed at the industrial level,” Cunningham said. “It gives them a lot of practical knowledge they simply can’t get in the classroom. Many students who complete the program often go on to rewarding careers, sometimes as energy managers.”
Filling the Gap for Manufacturers
Manufacturers benefit equally from the program since small- to medium-sized companies are often unable to dedicate resources to energy-savings initiative, said Cunningham.
“We have no problem getting clients,” he said. “These companies don’t have a lot of time to spend on detailed assessments that can help them save energy. It’s also a major advantage not to have to pay thousands of dollars to have an independent consultant perform an assessment.”
Cunningham said students find ample opportunities for plants throughout the state to reduce energy consumption and save costs, in addition to improving the productivity and reliability of production processes. He said students typically identify the biggest opportunities for energy reduction and costs savings with lighting and compressed air systems.
The program offers even more value beyond energy cost savings alone, Cunningham said.
“Like elsewhere, Tennessee manufacturers are not just looking to save costs but to gain a competitive edge. By helping manufacturers reduce energy cost, the TTU-IAC program helps them become more competitive. At the same time, students who participate in the program come out ahead by having a solid foundation in manufacturing processes and what it take to effectively and profitably manage the energy they consume.”
Students Help Tennessee Manufactures Gain an Edge
Manufacturers throughout Tennessee have discovered ways to take existing efforts to reduce energy costs to new heights and gain an edge in productivity and profitability, thanks to the Tennessee Tech University Industrial Assessment Center (TTU-IAC) program.
Many manufacturers have also implemented TTU-IAC’s recommended energy-reduction measures – including a host of projects involving compressed air systems. Here are just a few examples:
Eliminating Air Compressor Blow-off
A manufacturer of polyethylene terephthalate (PET) bottles in Cleveland, Tennessee, recaptured high-pressure compressed air from bottle testers and fed it back to the low-pressure side of the compressed air system for reuse, resulting in reduced compressed air demand. Yet the TTU-IAC assessment demonstrated the ability to further reduce the amount of energy and costs required for compressed air.
The plant operates three 900-horsepower (hp) centrifugal air compressors, each of which is rated to deliver 3,390 scfm. Before the assessment, the plant typically operated all three compressed air units. However, to prevent them from surging the bypass valves of the air compressor opened and each vented as much as 2,000 scfm of air.
TTU-IAC assessment showed how the plant could better sequence its air compressors to match the supply of air with demand. Now the plant typically only operates two of its air compressors, allowing it to avoid the need to blow off air. Doing so also saves nearly 3.9 million kWh and \$172,200 per year in energy costs.
Saving with Low-pressure Blowers
In Crossville, Tennessee, a porcelain tile manufacturer knew it could save energy by using zero-loss drain traps to expel water from its compressed air system. The TTU-IAC assessment, however, revealed how more best practices would help it achieve additional energy-savings.
Before the assessment, the plant used its three, 100-hp air compressors in part to supply air to 21 air knives and slit nozzles to dry and clean tile. The assessment showed the plant could use low-pressure blowers for the application instead of compressed air. In addition, students identified how the plant could eliminate the use of air hoses to clean dust off of machines – and save energy.
The plant later installed a total of 14, one-third hp low-pressure blowers and uses them in place of air knives for drying and cleaning. It also uses induction air knives rather than air hoses for dusting off machines. The initiatives save the plant nearly 111,925 kWh and \$14,000 per year in energy costs. Each initiative also paid for itself in less than one year.
Better Compressed Air System Control
Another company that took advantage of the assessments is a maker of automotive components in Murfreesboro, Tennessee.
The plant had implemented a number of best practices before the assessment, including the installation of a Variable Speed Drive (VSD) air compressor to efficiently meet fluctuations in its compressed air load. It also uses waste heat from the air compressor to provide additional space heating. Additionally, heat generated by the air compressors is ducted outside the plant during warmer months to keep HVAC energy costs down.
The TTU-IAC assessment showed the plant it could save even more energy. The plant’s compressed air system includes four, 150-hp air compressors. Three are fixed-speed units, while the fourth is a VSD unit. Before the assessment, the VSD air compressor would turn off first when demand for air was low.
After the assessment, however, the plant chose to use two fixed-speed air compressors as base-load units during normal production and use the VSD air compressor as a trim unit to for low-demand periods since it operates efficiently at part load. In addition, the plant now only uses two air compressors during off-production hours. The fourth air compressor serves as a backup unit.
In addition to cost savings achieved by better use of a VSD air compressor, better use of the air compressors gives the plant the ability to more efficiently deliver air where needed. Now, the compressed air system supplies air throughout the facility at 98 psi rather than 103 psi.
The use of the VSD on combination with a better compressed air control strategy saves the plant 353,703 kWh and \$23,844 per year in energy costs.
Addressing Compressed Air Leaks
Like other companies in the state, a manufacturer of hydrostatic transmissions in Morristown, Tennessee, had implemented a number of best practices before it brought in TTU-IAC for an assessment. Best practices ranged from the use of zero-loss drains to leveraging the waste heat of air compressors for heating during the winter months and more.
As part of the TTU-IAC assessment, the plant installed electric meters on its two rotary screw air compressors and monitored data over an extended period. It found the air compressors were working a significant amount of the time to maintain systems pressure as a result of air leaks. Subsequently, the plant implemented a leak repair program. Now, the air compressors work less to supply air used for production process, as well as remaining air leaks. The measures allow the plant to save 315,187 kWh and \$19,605 per year in energy costs.
For more information about the Tennessee Tech University Industrial Assessment Center, contact Dr. Glenn Cunningham, P.E., , email: GCunningham@tntech.edu, or visit https://www.energy.gov/eere/amo/industrial-assessment-centers-iacs.
All photos courtesy of the Tennessee Tech University Industrial Assessment Center.
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