Industrial Utility Efficiency    


It is becoming a “best practice” to install a variable frequency drive (VFD) air compressor whenever one is replacing an old air compressor.  As a result, real systems have fixed-speed and VFD air compressors, mixed.  I have observed several VFD compressor sizing methods.  In my last article, I referred to a common method: size one VFD compressor for the whole system.  This can work.  However, if it doesn’t meet a higher peak demand, one or more of the old compressors will be started, and a mixed system results.   Another method is to replace a compressor with the same size, but with a VFD.  If the compressor that was replaced is large, a big VFD is installed.  If small, a small one.

Air Compressors

There are many choices of compressor technology and types of controls that can be used for variable demands. Some examples are rotary screw compressors with inlet valve control: variable speed drives: load/unload control; or centrifugal compressors with variable inlet guide vanes. However, in many cases, the efficiency of the overall compression process can be reduced significantly during lower flow demands, leading to more power per unit of air flow being delivered. It is very important to evaluate different available options and see how a plant can run most efficiently.

Air Treatment

Compressed air is dried to prevent condensation and corrosion which can disrupt manufacturing processes and contaminate products. Water is the primary promotor of chemical reactions and physical erosion in compressed air systems. A myriad of desiccant dryer designs have been devised to provide “commercially dry” air, air having a dew point of -40°F or less, to prevent corrosion.  Desiccant dryers use solid adsorbents in granule form to reduce the moisture content of compressed air.


High speed bearing technology is applicable for aeration blowers operating at much higher speeds than the typical 60Hz, 3600RPM for cast multistage units. High Speed Turbo (HST) units are usually single stage (though some utilize multiple cores) and rotate from 15,000 to 50,000RPM. At such high speeds, standard roller bearings cannot offer the industry standard L10 bearing life. Two types of bearing technologies have come to dominate the wastewater treatment market for these types of machines: airfoil and magnetically levitated. Often the two technologies are compared as equals, however, in many significant ways they are not.

Compressor Controls

Load-sharing is an important part of a multiple centrifugal-compressor master control system. It minimizes blow-off based on the available turn-down. In addition, remote start-stop saves more energy if load floats between different ranges. Finally, adding a screw compressor and implementing a hybrid control system might save the most energy and provide the best back-up. In any case, a well-instrumented system allows engineers and operators to assess, optimize and tune the system.


Compressed Air Best Practices® Magazine interviewed Mr. Warwick Rampley, the National Sales Manager for Sydney (Australia) based, Basil V.R. Greatrex Pty Ltd. It’s not every day one is asked to deliver a system able to provide both a reliable compressed air dew point of -80°C (-112°F) and high purity nitrogen.  We work with some excellent technology suppliers and have engineered a rather interesting system.  Although our firm was founded in 1919, this application is one of the most demanding we’ve encountered. Basil V.R. Greatrex is a unique company as we focus only on compressed air measurement, compressed air quality and compressed air efficiency.


The design of wastewater treatment plants is changing, and it has something to do with LEGO® bricks. More specifically, it has to do with how large and complex LEGO structures are built. If you follow the instructions carefully, you build module after module, eventually piecing them together to create a fully functional and cohesive unit.


It’s one thing to move materials during the production process, but when it’s a finished product on the packaging line, choosing the right material handling system is essential. Getting it wrong results in squandered production time when product loss occurs, and wasted raw materials.

Cooling Systems

As a result of compressed air awareness training and a focus on energy management, two facilities in different parts of the world have reduced their compressed air demand substantially by removing vortex style cabinet coolers from some of their electrical panels and reworking the cooling systems.  These facilities were previously unaware of the high cost of compressed air and how much could be saved if other methods of cooling were used. This article describes some of their efforts in demand reduction.
SQF is a food safety management company that conducts audits and reports its findings on companies that voluntarily subscribe to its services. Once an audit is performed, SQF releases the data; from this data, other companies can determine who they want to use for packaging and manufacturing. To facilitate the process, SQF has released a guide that provides directives for processes used in manufacturing.
When the topic of discussion is making ice cream, the first thing that comes to mind isn’t heat, but at Nestlé’s Ice Cream factory in Tulare, California, heat is recovered from air-cooled air compressors to heat process water. “Right out of the gate, everything is pneumatic,” explains Tom Finn, Project Engineer with Nestlé Ice Cream Division. “Air cylinders and air driven motors, the process piping valves which divert, route, stop/start, and mix process fluids, our packaging machinery including rejection, cleaning and vapor removal processes, all of these rely on compressed air.
EnergAir’s unrivalled expertise in compressed air management is helping to save in excess of $50,000 per year at Whirlpool Corporation’s Ottawa, Ohio production facility. Whirlpool is the largest global manufacturer of home appliances and employs almost 70,000 people in more than 60 production and technology centres around the world. The Whirlpool plant in Ottawa manufactures a market-leading range of trash compactors, chest freezers, upright freezers and refrigerators.    
Compressed Air Best Practices® Magazine interviewed Frank Mueller (President) and Stephen Horne (Blower Product Manager) from Kaeser Compressors. Kaeser Compressors continues to grow both in the U.S. and internationally. We currently employ approximately 4800 people globally. In order to support the demand and maintain our superior quality and quality service levels, we continue to invest in people, facilities and technology.
Productivity is more reliable when equipment can be monitored to detect incipient failures and take corrective action before the plant goes down. But many devices, such as analog control valves, pneumatic valve terminals and field sensors, often do not offer diagnostic feedback, or it is not being used. This white paper describes how this problem is being addressed, and includes an example of pneumatic valve terminals that can monitor, among other things, open load or coil currents at the specific valve and pressure inside the valve terminal.
Compressed Air Best Practices® Magazine interviewed Pascal van Putten (CEO) of  VPInstruments.  -- We founded VP Instruments, in 1999, with the mission being to apply our experience with flow sensor technology to compressed air and gas flow applications in laboratories with a “one size fits all applications” concept. We did some trade shows and sold one unit during the first year – a tough start. So we hired a consultant who helped us re-package the technology completely. This led us to launch the VPFlowMate, in 2002, in a small and easy to use package. The company has taken off since then.
As the population continues to grow in the United States, industrial water use will need to continue to fall to help offset the increases in public-supply water use. Water-cooled compressed air systems provide an opportunity for sustainability managers to reduce associated cooling water consumption and costs. If switching to air-cooled air compressors is not possible, understanding the costs and the alternative types of liquid cooling systems is important.
Compressed Air Best Practices® Magazine interviewed Dr. Jay Varadaraj, (Managing Director) of ELGi Equipments Ltd. ELGi today is one of the world’s leading manufacturers of air compressors. Like most companies, however, it started with one ambitious person. My grandfather, Lakshminaickenpalayam Govindaswamy (this where the “L” and “G” in ELGi come from) was a bus driver for the British in 1918. He purchased one bus and proceeded to build a fleet peaking at 300 buses. He believed he was in the transportation business so he entered the airline business ultimately withdrawing however when this industry was nationalized.  
The compressed air system in most industrial and commercial facilities is vital to production machinery and processes. When it goes down so does the plant output. This important utility is often one of the most costly energy consumers in a facility. Yet most compressed air system operators have little knowledge of how their compressed air system is performing and, if problems have happened, do not have an accurate record of what went wrong.
Boeing Canada Winnipeg (BCW) has been recognized with the best improvement project of 2013 within the Boeing enterprise worldwide. A cross-functional project team including BCW staff, Manitoba Hydro technical support, and design engineers from Alliance Engineering Services, Inc. used innovative high-pressure storage to reduce the required size of their air compressors and save substantial utility energy and demand charges.