Air Compressors

By far the most important development in the world of screw type air compressors has been the introduction of variable speed control using electronic variable frequency drives (VFD’s). Systems that run with at least one air compressor at part load can almost always operate more efficiently if a well-controlled VFD is added to the system. But what if a system has two or more VFD units? This article discusses the challenges in controlling multiple VFD air compressors with some suggested solutions.

The team is building on engineering concepts that were used to develop the first hydraulic air compressor at Dominion Cotton Mills, Magog, Quebec, Canada, over 100 years ago. The basic principles of the HAC were then used to produce compressed air at 17 locations worldwide, including the last at Ragged Chutes near Cobalt, Ontario, Canada, over 100 years ago.  This article discusses the development the HAC in this decade and the continuing work at Laurentian University, Ontario, to modernize the concept.

The compressed air system at the mail sorting facility has been in service since the 90’s. Two older 50-horsepower (hp) air-cooled fixed-speed lubricated air compressors are housed in the equipment room of the facility. The air compressors duty cycle alternates between one another on a set schedule. A 240-gallon wet storage receiver is used to help with air compressor control, with the air flowing through the receiver to a non-cycling refrigerated air dryer and system filters before finally being passed to the plant.

Often, multiple centrifugal air compressors are set up to simply react to air demand, which requires the system to not only meet the new demand, but also make up for air depleted in the main header. This typically results in too much supply, which results in bypassing the air to atmosphere. The result is wasted energy use.

As demand for compressed air use continues to grow, the future looks bright for distributors who design, sell, install and service compressed air systems. But perhaps only one thing stands in the way of continued growth and profitability for the vast majority of distributors throughout the United States: the shortage of experienced air compressor service technicians.

Compressed Air Best Practices® interviewed Sang Woo Lee, CEO of Coaire Corporation.

I had enough experience with compressors used in refrigeration to see there was a lot of area for growth, particularly with scroll technology given that its an oil-less air compressor in addition to its efficiencies, noise level and ability to offer customers longevity. I also liked that Coaire has a long history of innovative air compressor technology. In 1968, it became the first Korean company to develop and manufacture a reciprocating air compressor. Later, it became the first Korean manufacturer of rotary screw air compressors, which occurred after it established ties with SRM to develop unique airend technology.

After getting its start manufacturing cost-effective products to the healthcare industry, 40 years later, 1888 Mills has become the fourth largest towel manufacturer in the world, and the largest towel manufacturer in the U.S. With facilities in the United States, Pakistan and Bangladesh, 1888 Mills’ towels are used in almost every corner of the world. 1888 Mills is recognized as a leader in innovation in the textile industry and produces 176,000 pounds of towels per week.

To address a mandate for cutting operations energy usage at facilities by 25 percent without major capital expenditures, a major manufacturing company set its sights on better control of its compressed air systems.  The project, implemented at 10 manufacturing plants over the course of three years, saves the company \$977,093 annually in energy costs – and was completed with zero out-of-pocket costs.

Held September 16-19, 2018 in Chicago, the first-ever event drew 750 attendees who came together to learn and share ideas about the countless ways to achieve efficiencies with compressed air, blower, vacuum and cooling systems – and in the process – save energy and improve profitability.

Many food processing plants are already using oil-free compressed air at a low-pressure dewpoint. This has required the use of two-stage oil-free screw air compressors, centrifugal air compressors and other technologies, as well as regenerative dryers of one type or another. The most common oil-free air compressor in industry is the two-stage “dry screw” machine and the most common regenerative dryer type is the heatless type. These are combined in many food processing, pharmaceutical, and high-tech plants.