Industrial Utility Efficiency    

System Assessment

While late summer may not be the time of year many of us think about heat recovery, the potential for energy savings in compressed air systems should be on our minds year-round. For those involved with the compressed air systems within International Wire Group’s facilities, energy savings is on their minds each day. This culture of continuous improvement has everyone on the lookout for savings wherever possible.

Compressor Controls

UniFirst is one of North America’s largest workwear and textile service companies. They outfit nearly two million workers in clean uniforms and protective clothing each workday. Founded in an eight-stall garage in 1936, the Company has grown to 240 customer servicing locations throughout the U.S. and Canada servicing 300,000 business customer locations. The subject of this article is an energy-saving Air Demand Analysis (ADA), conducted by Kaeser Compressors, at UniFirst’s centralized 320,000 square foot hub Distribution Center located in Owensboro, Kentucky.

Piping Storage

The company specializes in fabrication of precision assembled customized parts for OEM’s and system integrators. Since 1997 the company has steadily grown in size and capacity as the demand for its high quality fabrications has increased.  Through the years, many new CNC machines, laser cutters and powder coat painting operations have been added, but with all the expansion the facility has amazingly kept the plant compressed air consumption low. This has been achieved by following excellent “best practice” compressed air efficiency principles and by keeping watch on system waste.

End Uses

A chemical plant spends an estimated $587,000 annually on electrical energy to operate their compressed air system. In addition, the plant has an expenditure on rental air compressors of equal or greater size - but this will not be covered in this article. The plant was built in the 1940s and modernized in the 1970s. The plant generates its own power and serves many processes. The average cost per kWh is $0.0359.


A Canadian chemical plant installed a large heated blower-purge style compressed air dryer, years ago, to condition the instrument air system against freezing temperatures.  The dryer selected was oversized for the connected air compressors and had unused on-board energy savings features.  A compressed air assessment revealed the site air compressors and compressed air dryers were running inefficiently and causing in-plant pressure problems.  Repairs to a compressed air dryer and the replacement of aging air compressors and dryers has reduced compressed air energy costs by 31 percent.

Air Treatment/N2

This plant has three production lines producing snack food. Depending on the time of year and production demand the plant can operate anywhere from no production lines to all three production lines. A thorough supply and demand-side system assessment was done at this plant. This article will focus on some recommended demand-side reduction projects including nitrogen generation, air vibrators, leaks and vacuum venturis.


Petro Chemical Energy, Inc. (PCE) specializes in energy loss surveys for the refining and chemical industries. We’ve been providing Compressed Air Leak Surveys, Nitrogen Leak Surveys, Steam Leak Surveys and Steam Trap Surveys – for over twentyfive (25) years. We operate totally independent of all equipment manufacturers to ensure our clients receive a complete and unbiased report of the leaks in their facility. PCE has conducted compressed air leak surveys for hundreds of customers at thousands of sites. Undetected, compressed air and gas leaks rob efficiency in manufacturing and processing industries. As a result, businesses lose millions of dollars annually in energy costs and lost production time.


Energy, in all forms, has always been a key Lantech focus. It was, in fact, a key element of the core packaging problem the company’s founders set out to address. They saw an opportunity to capitalize on an inexpensive and under-used resource – stretch film – to displace a high materials cost and energy intensive way of unitizing pallet loads of products – shrink bagging.

Vacuum Blowers

Every municipality and utility is facing the reality of rising energy costs. In 2010, the Town of Billerica, MA, which is located 22 miles northwest of Boston with a population of just under 40,000 residents, engaged Process Energy Services and Woodard & Curran to conduct an energy evaluation of the Town’s Wastewater Treatment Facility (WWTF) and pump station systems sponsored by National Grid. The objective of the evaluation was to provide an overview of each facility system to determine how electrical energy and natural gas were being used at the facility and to identify and develop potential costsaving projects.
Compressed air is used in more than 70 percent of all manufacturing activities, ranging from highly critical applications that may impact product quality to general “shop” uses. When compressed air is used in the production of pharmaceuticals, food, beverages, medical devices, and other products, there seems to be confusion on what testing needs to be performed.
In compressed air systems, every adjustment or system modification has consequences, so, before making changes, it’s important to understand how those changes will affect each piece of equipment.  For example, simple things — such as lowering the compressor’s pressure set point, or failing to maintain the compressor’s aftercooler — can result in moisture contamination occurring out in the system. Why? Because the effects of these actions reduce the air dryer’s capacity. In this article, I address some ideas that can make your system more reliable.
Ahresty Wilmington Corporation (AWC) was founded in 1988 and is located in Wilmington, Ohio. Currently AWC employs over 900 people with sales totaling $192 million. They have grown steadily, all while continuously improving and staying on the leading edge of technology. AWC is a tier-1 automotive supplier servicing their entire customer base in the United States. AWC has established an efficient and integrated production system that incorporates die-casting, finishing, machining, and assembly operation using just-in-time production methods to provide its customers with quality products at a competitive price.
In recent years, we have seen an upward trend of higher production manufacturers wanting to integrate their air gauging quality checks from a stand-alone, outside-of-machine device where the operator is performing a manual check to an automated in-process gauge. There are several reasons for this trend, including higher quality standards, tighter tolerances, as well as running a leaner operation. The benefits are 100 percent inspection of the required geometric callout, as well as handshaking between measuring device and machine to make each piece better than the prior one. It also removes any bad parts.
When a company is considering making an investment of more than a million dollars in system upgrades, it is crucial for them to review all options to get the best return. By exploring energy efficiency impacts throughout the entire compressed air system, vendors can propose projects resulting in both a larger sale for them and increased financial benefits for their customers, while still meeting capital expenditure guidelines. This “best of both worlds” scenario was evident when a foundry in the Midwest was evaluating options for replacing its steam system used to drive the plant’s forging hammers.
EnSave, an energy auditing company based in Richmond, Vermont, recently performed compressed air audits at two facilities of a leading U.S. steel manufacturer. Both plants are mills that melt, cast, and roll steel to produce a variety of products, including: rebar, merchant bar, steel flats, rounds, fence posts, channel bar, steel channels, steel angles, structural angles and structural channels. These products are used in a diverse group of markets, including: construction, energy, transportation and agriculture. Compressed air is provided at 100 psig in both plants for a variety of applications — from optical sensor cooling to pneumatic cylinders for stacking finished products.
Compressed air has moved to higher visibility in the energy conservation field, and the buzzwords abound: “the fourth utility” — “your most expensive utility” — “eight times more expensive than electricity” — “a quarter-inch leak costs $9,000 in wasted energy.” This greater awareness has also produced compressed air auditors that are springing up like summer dandelions. With audits available from many sources, it is important to understand what plant operations, engineers and maintenance managers should expect from a complete audit — or more aptly — a complete air system review.
As a reader of this journal, you are well aware that large compressed air systems often have significant wasted air — often from leaks — that represent tens of thousands of dollars of waste per year. However, it is our experience that the so-called “low-cost” measures identified often go un-repaired, while other more costly capital projects get funded. Why? With an ROI of a half year or less, they seem like IQ tests to many compressed air auditors.
Many thousands of dollars of annual electrical savings are being achieved worldwide using special purge reduction controls on desiccant air dryers. These controls reduce the expensive purge air that must flow through the dryer to regenerate the desiccant beds. But, unexpected problems with these controls can cause hidden problems that can reduce or eliminate the savings.
After more than 25 years in the compressed air industry, it still amazes me that many plant personnel and even those who sell compressed air products for a living don’t fully understand the relationship between flow, or volume (cfm), and pressure (psig). Walk into many body shops or small manufacturing plants, and you will find the compressor operating at an elevated pressure to satisfy the “demand.” If a plant has low air pressure on the production floor, what is the first thing that the maintenance professional does? You guessed it: He or she “jacks” up the pressure on the compressor, not realizing that he or she made the problem worse.