Compressed air has been a go-to tool for a long time, and it might be easy to think that not much has changed in the industry. If we look closer, though, we can identify important developing innovations that will change the efficiency of compressed air systems worldwide for years to come. Some of these have to do with better equipment design and modern electronic devices being applied to systems, and some changes are being driven by compressed air users’ new level of awareness about energy efficiency. Following is a look at trends that are making an impact and saving compressed air users millions of dollars worldwide.
Equipment design innovations
In the area of equipment design, there has been excellent development. “Lubricant-cooled rotary compressors continue to improve in performance as modern designs take advantage of newer materials and manufacturing procedures,” says Hank Van Ormer, founder of Air Power USA. “This improves not only machine performance but also reliability. The same can be said about oil-free rotary screws.” Van Ormer sees a clear shift to lubricant-free compressors, especially in industries in which it is important to have a very clean supply of compressed air. He adds: “Centrifugal compressors are improving, too; modern manufacturing methods are generating better and better aeros, with resulting constant basic performance improvement. Magnetic bearing drives are eliminating all frictional drive losses of the conventional antifriction bearing, bull gear, and pinion. This results in extremely low idle input energy and extremely fast time from load to idle or stop and back to load.” Van Ormer points out that the shift to lubricant-free allows users to use the heat of compression, which is typically wasted, to help generate instrument-quality compressed air with very low dewpoint.
The introduction of the Compressed Air and Gas Institute’s performance verification program has helped buyers of air compressors and dryers compare equipment and choose the best units for their applications in terms of efficiency. As noted on the CAGI website, the performance verification program is a third-party testing program that validates manufacturers’ claims about rotary compressor and refrigerated dryer performance. The program is intended to provide “reliable and verified performance data for rotary air compressors (5-200 hp) and refrigerated air dryers (50-1,000 scfm).”
The equipment data sheets that the CAGI program specifies are available on CAGI member websites; these display the energy characteristics of equipment in a range of sizes to aid in comparing various makes and models. Sheets have been developed for fixed-speed, variable-frequency-drive, centrifugal, and variable-displacement compressors. Specific sheets are also available for refrigerated air dryers.
It is likely that the CAGI data sheets have been one of the catalysts to encourage manufacturers to improve their equipment performance numbers. Designers now are making significant efficiency gains in equipment design. Customers, too, are driving this change, as they are now more aware of the lifecycle costs associated with compressed air and are turning to the CAGI data sheets to help them with their equipment choices.
Continuous system monitoring
The monitoring of compressed air systems has come a long way in recent years with the improvement of industrial instrumentation as well as the emergence of flexible communications, easy-to-use data collection systems, and cloud databases. In the old days, very little compressed air energy and flow data was collected from compressor rooms across the world; now, if users care to do so, they can outfit their systems with modern electronic sensors that measure all manner of key performance indicators. “Since 2005, we have been seeing a trend toward continuous monitoring (to ensure) that compressed air systems are running efficiently in the long run, not just during and shortly after the implementation of system improvements,” says Jan Hoetzel, principal of Airleader USA. Nicolas De Deken of Energair Solutions describes his company’s experience: “On almost every installation of our newly designed compressor monitoring system, saving opportunities were identified,” he says. “Initial savings can quite often be delivered by small, low-cost measures such as reducing the operating pressure, switching off compressors during times of no production, and achieving better syncing and cascading of compressor pressure set points.” These opportunities are easily recognized when the system is fully measured and tracked.
These energy monitoring systems often are part of compressor control systems that coordinate and orchestrate the operation of the air compressors in multicompressor configurations. The key to these systems is making the industrial user aware of the efficiency of the system at all times, which can allow users to compare actual efficiency against a target number and take action if there are problems.
Companies that are not traditional players in the compressed-air industry but that have expertise in collecting, storing, and processing Big Data are developing cloud computing systems to help users keep their systems running at lower costs while also warning of looming equipment failure. Lightapp has developed some useful data collection, analysis, and comparison tools that have turned heads, so much so that the company is in the midst of a multimillion-dollar project that is monitoring a number of large compressed air systems in California and is being funded through a California Energy Commission grant.
Early results indicate that the new efficiency awareness that customers receive is leading to significant energy gains when improvements are done; these are often low-cost/no-cost adjustments to a system. Other companies developing similar systems available worldwide are Enersize and EcoPlant. These systems don’t stop at measuring compressor systems; they are designed to be used also to track other plant utilities in order to provide a complete package of monitoring, analysis, control, and predictive maintenance tools.
Not to be outdone, some compressor companies are adapting their traditional products, adding web servers to their compressor controls and offering monitoring systems that link to cloud database services – often by cell modem, bypassing the traditionally stringent rules of the plant IT department. Kaeser touts an Industry 4.0-friendly control and monitoring system. Atlas Copco and Sullair and others have developed similar systems, all allowing customers to track compressor maintenance conditions and energy consumption companywide across the world, should this be desired.
Compressed-air component manufacturers also are offering compressed-air measuring systems to help users track pressures, flows, power, and air quality wirelessly using in their systems. Parker’s SCOUT system and CDI Meter’s wireless mesh node communication protocol offer easy-to-use connection methods. VP Instrument’s VP vision offers dewpoint, flow, pressure, and power instruments consolidated in a single, easily understood, remotely accessible display.
“While I don’t think the industry has actually got its head around complete system monitoring or what is possible with a systemwide plan, I think industrial users are thinking they should now be monitoring their own systems,” says Warwick Rampley, a compressed air system auditor based out of Hong Kong. “Factories are starting to get smarter with their purchases, with lots of intelligent software being developed out there. Companies can now calculate how a given piece of equipment will actually affect their system, so they want data gathered to feed the simulation of various equipment conditions. This enables them to make the most informed choice.”
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Compressor control
Asked about leading compressed air trends, Frank Moskowitz, Atlas Copco’s U.S.-based Airscan expert, doesn’t hesitate: “Compressor control is my number one choice,” he says. “Immediate and significant energy savings can be had with a little attention to how air compressors are controlled.” Moskowitz is also the top trainer at the Compressed Air Challenge, an organization dedicated to awareness training to help industrial users realize the high cost of compressed air and figure out what to do about it in their organizations.
Indeed, the compressor controls that compressor manufacturers and third-party companies are offering are becoming more and more sophisticated as instrumentation and data processing develops over time. Controls are starting to use artificial intelligence to better operate systems with smart combinations or different sizes of compressors. Instead of selecting compressors in an ordered priority, the newer controls have the ability to select the best sizes and types of compressors to match the load in the most efficient manner possible. These systems are capable of integrating all types of compressors, including multiple variable-frequency-drive (VFD) units, and keeping these variable compressors in their sweet spots where possible. Newer developing controls also are capable of providing continuous real-time display or system conditions to handheld devices such as smartphones or tablets, providing data logging for later troubleshooting and generating comprehensive reports of energy characteristics and maintenance recommendations. More often that not, the compressor controllers are linked to the internet to provide both you and your service company a heads-up by email or text when things go wrong or when conditions that could spell trouble for your system are developing.
“I would normally have listed VSDs as a trending innovation – particularly with lubricant-cooled rotaries – but over the years, we have seen so many misapplications that not only affect the efficiency negatively, but also they reduce the reliability,” says Van Ormer. Adds Rampley: “Many people think that one big VSD compressor will automatically save them money, when in fact the opposite may actually occur. Companies are starting to look at total lifecycle costs, which include operation and maintenance. This tends to show that having a selection of smaller units operating more efficiently is better than having just one big unit.” Indeed, the word is getting out that, while excellent when properly applied, compressors with variable-speed-drive technology need to be sized and controlled in a different manner than in days gone by to avoid problems like “control gap” and to sidestep inefficiency at both full-load and minimum speeds. Newer, more-modern controls have taken these challenges into account for the customer’s benefit.
Demand-side reduction
With the focus on compressed-air energy reduction, many system owners as well as product suppliers are starting to look more carefully at the demand side of compressed air systems. Energy can be saved by more efficiently producing and conditioning the compressed air on the supply side, but often the biggest savings will come from reducing compressed-air demand. Through awareness training provided by various organizations and through a constant stream of marketing, the message is getting through that users need to be aware of how much compressed air they are wasting. Not everyone is satisfied, however. “There is still too little focus on end uses such as leaks, showing a lack of maintenance, inappropriate use of compressed air, and artificial demand” says Bo Kuraa, a Denmark-based technical vice president with Enersize. “But for the common factory maintenance person, this is too complicated; this requires better study and analysis of the system by trained compressed air energy professionals.” Explains Murray Nottle, an Australia-based compressed air expert with the Carnot Group: “Demand-side efficiency is important; this means looking beyond air leaks and wasteful uses. There is so much more that can be done for so much less.” Adds Moskowitz, “No matter how efficient the compressors are, like 1% to 2% better than someone else’s, just walk into the demand side and look carefully, and you can save 20% to 30% more energy there.”
While compressed air auditors have known for years that demand-side reduction efforts are very effective, equipment manufacturers are now starting to develop excellent solutions to help reduce compressed air consumption. One auditor reported seeing intelligent control of screwdrivers used in assembly of products – the valve controlling the drive was electro-pneumatic. Analog input from the screwdriver told the valve what pressure to use, saving flow and providing consistent torque. SMC, for its part, has developed a leak detection system that analyzes the operating characteristics of pneumatic assemblies and provides feedback to the operator if leaks develop within the assembly. Likewise, ABB recently announced an energy-saving “ability-connected” paint atomizer that uses sensors and real-time smart diagnostics to optimize painting quality in robotic painting operations. Not only can this reduce the compressed-air consumption by a reported 20%, but also it can reduce the quantity of paint used and the rework required. Van Ormer notes that he has seen the use of 3D printing to produce better compressed-air components, particularly in the area of compressed-air vortex vacuum generation with compressed air.
An always-evolving field in demand-side management is leak detection. A number of companies are developing cutting-edge ultrasonic leak detectors to make the job of finding and fixing leaks easier and more efficient.
Leak detectors with integrated cameras, on-screen tools to estimate leak flow, and accompanying software to generate useful audit reports are already available; many more are in the works. Some companies have useful smartphone apps that are available for free or at low cost in mobile app stores. Look for names such as LeakSurvey, LEAKReporter, iAirAudit, and Inspectab.
Air auditing
“I’m seeing the rise of the ‘true compressed air consultant,’ ” says Murray Nottle, an auditor himself. “When I say ‘true compressed air consultant,’ the first requirement is that these consultants can’t be part-time (or full-time) equipment salesmen. Their only income comes from providing the customer with advice and engineering and audit services.” The development of the compressed-air-assessment specialist trade has grown slowly over time, with mixed results. By now, almost all compressed-air companies have someone working for them who can do adequate assessments – often provided for free to the customer.
Many working in the field can service customers with superior unbiased advice and analysis. But too often, inexperienced auditors, lacking the understanding of common measurement principles, will steer customers in the wrong direction, driven by their need to supplement their income through equipment sales. A new development in the field is the effort to develop a nationally recognized Certified Compressed Air Practitioner certification; this work is being led by CAGI and the Compressed Air Challenge. Practitioners will take final qualifying exams to prove their knowledge and skill. It’s hoped that this will encourage the education of those providing auditing services.
The compressed air industry is changing in a good way. Keep an eye on new developments to avoid getting left behind!