Industrial Utility Efficiency

Fifteen Years of Compressed Air Best Practices Support Gentex Business and Production Goals

Gentex Installation

Gentex Corporation implemented compressed air best practices at multiple facilities, leading to energy costs savings, increased productivity, improved sustainability – and more.

While many businesses strive to plan, install and maintain a compressed air system that fulfils the company’s specific needs, I’ve found that implementing compressed air best practices not only accomplishes specific goals, but also results in time-tested advantages that aid in the overall business and production goals of the organization.

Throughout the last 15 years, like many companies, who have been following the growth and change in the compressed air industry, using compressed air best practices will contribute to the success of each compressed air system. 

For me, the specific goals these practices must meet are to supply production with reliable pressure, flow, and clean dry air. Broader goals include saving money for the company, easing the burden on the environment, and most of all never shutting down production. 

This case study is 15 years in the making and documents the changes over time that have been made to our systems in keeping up with compressed air best practices at our organization as a Tier-1 automotive supplier, fire protection device manufacturer, and producer of dimmable aircraft windows. Our compressed air systems support all aspects of manufacturing, as well as OEM-manufactured components such as microchips, circuit boards and special glass processes and corporate lab services.

This is why we strive to use the best and most advanced technologies available for our compressed air systems, from air compressors to auxiliary equipment.

I started implementing this new compressed air best practices approach in 2004. When new production lines and processes were installed, the tools to measure and help maintain the compressed air supply and demand side of each system were also added. As the company grew so did needs of each system. What follows is a timeline to illustrate this progression. 

Year 2004

  • All future air compressor systems that are production-critical must have a planned air compressor unit as a backup only. This air compressor is off except for maintenance to main system air compressors, or if a fault occurs with an on-line machine. The backup units are also rotated with the main system units.
  • PSI gauges added on all air compressor equipment, filters, and headers in three buildings (2004). Currently working a new Plant 10 building header (as of 2019).
  • Flow meters added to main air compressor outlet headers.
  • Compressed air audit completed as required to keep up with growth rate.
  • Pressure transducers added to main compressed air header with alarm/paging capability.

Year 2005      

  • All production lines must have a visible cfm flow meter on each production line supply header.
  • Use 45-degree elbows to install air compressors into main header.
  • Pressure transducers added to far end of building near end use with alarm/paging capability to measure pressure drop and diagnostic information.
  • Built a portable flow meter on a pipe with gauges to prove out “point-of-use equipment.”

Year 2006

  • Installed first oil-flooded Variable Speed Drive (VSD) air compressor at Plant 4, saving significantly in electrical costs annually over fixed-speed air compressors and more efficient pressure stabilization.
  • Moving forward, if applicable, all systems are required to have a VSD air compressor.
  • Added centrifugal water separator before air dryers because there was no room for a wet tank.

Year 2007

  • Installed second VSD oil-flooded air compressor in Plant 3. Now saving substantial electrical cost annually and smoothing out the pressure output.
  • First building flow controller installed to Plant 3 demand side of the compressed air system.
  • Incidentally, despite popular belief at the time, using a VSD air compressor (and a flow controller plumbed after the dry tank in the main header) did not work out so well for the organization. As a result of this discovery, the flow controller was removed, thus beginning the consideration of a central controller.
  • Also, the appropriate size air compressor was installed to overcome control gap.

Year 2008

  • Added oil and water indicators to all dry tanks to alert the facilities department to possible contaminants, and thus, protecting production processes. All were –  and continue to be – inspected and replaced at regular intervals.
  • First compressed air leak audits performed for all compressed air systems and associated plumbing distribution loops. For compressed air alone, this cost savings is unparalleled for our organization. This includes 43 audits across multiple plants. This process is completed annually and as of about 2017 these audits qualify for a rebate from the local power company, which makes the audit cost less. Documented leak audits can and have led to substantial energy cost savings.
  • Added the testing of flow controllers instead of standard regulators on two production lines in Plant 2 to respond for faster flow changes, making pressure more stable and reducing pressure drop. It continues to be successful.

Flow Controller

Testing of flow controllers has been a key part of Gentex’s ongoing effort to implement best practices.

Year 2009      

  • Began point-of-use analysis and documentation of pressure and flow requirements to over 250 pieces of equipment. The goal was to lower the plant pressure without faulting out a production line. This was successful as the plant was taken from 125 to near 100 psi without a single end-use component fault. Lowering the operating pressure will allow less money to be spent on energy and help reduce the company’s carbon footprint.
  • Plant 5 had the addition of a system flow controller. This installation dropped the demand side of the compressed air system to 80 psi. As mentioned, lowering power consumption helps with sustainable goals that are becoming more prevalent in the compressed air industry. We also added a 1,000-gallon compressed air storage tank. This eliminated the need for a larger air compressor, in turn, saving equipment and electrical costs based on dropping the pressure.
  • Zero loss drains implemented for all condensate drains. For critical locations, I plumbed two in parallel in case one failed. This feature saves money as no compressed air is wasted when the air compressor condensate is discarded to the drain.

Year 2010

  • Installation of a third VSD oil-flooded screw air compressor in Plant 6, creating a more stable pressure band. Production currently has a 100 to 88 pressure band to run the four machines. The variable speed unit maintained a tighter pressure band while the base machines came on as needed. (The average psi band moved to 97-93 psi.)
  • The backup machine of this system can be called upon five to eight psi sooner than the current pressure band control method.
  • Standardized all compressed air plumbing to non-rustable piping.

Year 2011

  • Installed a fourth VSD oil-flooded screw air compressor in Plant 1. Using the VSD unit is saving electricity and resulting in a smoother pressure band for the third-shift operation.
  • Central controllers and data acquisition equipment purchased and installed for compressed air systems at Plants 1, 2, 3 and 4. The central controller reduced the pressure band depending on the building (worst case) from 30 to 3-4 psi.           
  • Kilowatt (kW) meters required on all air compressors moving forward in addition to central controllers, which monitor power consumption/amp/voltage and alarm any abnormalities to the end-user.
  • The central controller data allowed faster root cause analysis and saved downtime and maintenance costs. The software used trends every three to five seconds.
  • Compressed air, reverse osmosis, and Nitrogen (N2) flow data charts became available for facilities viewing.
  • Continuous diagnostics of compressed air system includes air compressor faults, dryer faults, inlet and outlet filter differential/air flows/kW/dewpoints/cooling water, air and oil temperatures. All are now monitored and can alarm out to end-users.
  • Continuous in “in-house” system energy audits began. The central controllers and data acquisition equipment allowed us to have compressed air and energy audits performed in house 24 hours/day, seven days a week. There is no need to wait for contractor support for auditing.
  • All current (and future) compressed air, purified water and nitrogen flow meters were all added to the new data logging system with alarm capabilities via 4-20 milliampere (mA) output through the company’s Intranet. Overuse of air began to be managed from an operator’s desk computer. System reports and graphs allow processes to be monitored more closely. The new detailed data minimized wasted compressed air, nitrogen and purified water by alarming at high flow rates. As such, it saves on energy costs each year.
  • Plant 3 is now using a central controller to operate the compressed air system. The pressure is stabilized at the desired 90 psi for three shifts, which is saving energy over the previous pressure band control that swung from 100 to 125 psi.
  • More precise control of the air compressors would allow for energy savings on non-production days.
  • All data points were to have alarm options.
  • Addition of desiccant heated blower purge desiccant dryer in Plant 1 for electronics production. This improved microchip and circuit board production by adding ultra-dry air to support production.

Year 2012

  • Upgraded Plant 6 to larger fifth VSD air compressor and moved current VSD unit to storage for use at a later date. Added a central controller with all the options previously described.
  • Added larger compressed air storage tanks; wet and dry side. All tanks are required to be powder coated on the interior and exterior. Wet tank volumes should be less than dry side tank volume(s).
  • Changed to thermal mass compressed air dryers when new or upgrades are needed making the drying side of the system more efficient.

Compressed Air Storage Tanks

Gentex added larger compressed air storage tanks to its operations for increased compressed air storage.

Year 2013

  • Upgraded Plant 2 with sixth VSD air compressor that was stored from Plant 6 upgrade of 2012.
  • Installed first “oil-free” VSD dry screw air compressor in Plant 8. Making this the seventh VSD air compressor. in creating a new standard for oil free air. A typical oil-flooded rotary screw air compressor could consume one half gallon of oil every 2,000 hours, which means one must rely on filtration to remove the oil from the air. This possible oil contamination is 99% eliminated with this type of screw air compressor as there is still oil mist coming from the gear box breather assembly.
  • Added another central controller for the compressed air system and data management.
  • Began to install zero loss drains with alarm outputs that would create email and texting alerts. A factory programed drain fault will shut down an air compressor in 10 minutes. This condensate system has a primary bank and a secondary bank. If a primary drain fails then an alert goes out, and automatically a secondary drain picks up the condensate and sends it to drain. The compressed air system was programed to look at the secondary drains, which gave the facilities team time to fix the primary drain before the air compressor shuts down as required.
As a best practice, Gentex began to install zero loss drains with alarm outputs on its compressed air systems. Shown are drains with different elevations.

Year 2014

  • Installed two oil-free centrifugal air compressors in Plant 7. As described above, possible oil contamination is 99% eliminated with this type of unit. As with the dry screw air compressor this also has a breather assembly that can mist an oil vapor.
  • Installed another central controller for air compressor and data management.
  • Began using a compressed air testing lab to confirm air quality.
  • Began installing Y fittings for air compressor header hookups.

Year 2015

  • Upgraded Plant 2 with two oil-free centrifugal air compressors.
  • This upgrade enabled us to hook four buildings together with the four centrifugal air compressors.
  • The four buildings went from seventeen 100 horsepower (hp) units to four 450 hp units. This lowered compressed air system maintenance costs for the four-building system. More importantly, it reduced the oil contamination risk to critical processes.
  • Added a flow controller to an individual process in Plant 1 production line, reducing pressure drop and greatly improving pressure stability.

Year 2016

  • To improve diagnostic time, all new or retrofitted air drops to production lines and or separated processes required installation of a pressure gauge with a ball valve to isolate the gauge in case of repair, and when required, a scfm flow meter.

Year 2017

  • Addition of one oil-free centrifugal air compressor at Plant 2 to maintain a backup unit to the four-building distribution system.

Year 2018

  • Installed the first “no-touch or wear” centrifugal VSD air compressor with permanent magnet motor technology and active magnetic bearings in Plant 6. With this unit, all air compressor core components are integrated on a levitating shaft without any mechanical touch or wear. Previously a great deal of money was spent annually to maintain an oil-flooded unit; now it is substantially reduced (although it still needs air filters). Over a five-year period, there will be exceptional savings. There are no bull gear, impeller, motor bearings or oil seals to service. There are no oil filters to change and oil to discard. There is no oily condensate water to filter, and no oil leaks to fix or separators to replace. Eliminating the waste of used oil and the associated oil components going into landfills will help with sustainability measures. For the corporation’s purposes, this was another big upgrade from other traditional air compressors.

Tamturbo centrifugal compressor

Gentex installed one of the industry’s first “no-touch or wear” centrifugal air compressors, which resulted in substantial costs savings.

Year 2019

  • Began working with production maintenance and a leak audit (energy) company to scope individual production lines (over 200) for air and nitrogen leaks near production-critical processes. While our Facilities Group has been auditing the pipelines within buildings, sensitive end-use audits were not included prior to this year.
  • Company-wide, over 88 zero loss drains are now in use.
  • Upgraded Plant 2 robot cells to larger piping and flow controllers instead of traditional regulators. Pressure is very stable.
  • Over 850 data points are now being monitored through eight central control systems. All inputs are manageable from an operator’s desk.


Compressed Air Best Practices Pay Off

This 15-year case study can account for many cost saving initiatives. Not described in this article is the amount in electrical savings from better control changes, faster troubleshooting and repairs which creates less downtime.

Gentex will continue to look for new cutting-edge technology that can improve its processes and save money while lowering the carbon footprint. Paired with compressed air best practices, we can look forward to another 15 years of systems that are energy efficient, reliable, and easier to maintain. Whether it is a new install or a retrofit, other companies too can benefit from utilizing the best of compressed air practices. 


About Gentex Corporation

Headquartered in Zeeland, Michigan, Gentex Corporation is a global, high technology electronics company that is vertically integrated in highly automated electronics, CMOS camera development and manufacturing, vacuum coatings, and glass bending and fabrication. It  specializes in a broad spectrum of technologies and processes to deliver high quality products to the automotive, aerospace and fire protection industries. For more information, visit


About the Author

John Bilsky is experienced in engineering design/improvements and maintenance for compressed air, nitrogen, and water purification systems, including those involving reverse osmosis and deionized water. He also has in-depth knowledge of production, as well as management of capital projects. Bilsky serves as the Facilities Specialist at Gentex Corporation for Compressed Air, Nitrogen, and Purified Water, email:, LinkedIn:

All photos courtesy of Gentex Corporation.

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