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.”