How Data-Driven Audits Eliminate Compressed Air Waste

Turning Hidden Inefficiencies into Measurable Profit with CALMS

Compressed air is often called the “fourth utility,” yet it remains one of the most inefficient and expensive energy sources in industrial manufacturing. Without precise visibility, plants often over-pressurize systems, run oversized compressors, and ignore critical mechanical faults.

This report details how the CALMS approach - combining global control with local support - systematically detects and solves complex compressed air problems. By leveraging data audits and real-time monitoring, these facility interventions resulted in significant ROI, often within a single month.

I. The High Cost of Artificial Demand: Pressure Optimization

One of the most common inefficiencies in industrial plants is “artificial demand” - operating the system at a higher pressure than necessary to compensate for pressure drops or perceived reliability issues.

Case Study: Food & Beverage Production (Marbo Pepsico)

A food production facility was running five oil-free screw compressors and one VSD compressor. The system suffered from poor specific power and an excessively high pressure setpoint averaging 8.6 bar.

By analyzing the system dynamics, the team identified that the pressure could be safely lowered without impacting production.

• The Fix: The control system was adjusted to operate at a lower pressure target, achieving a reduction of 1.8 bar.
• The Result: While the specific power remained constant due to flow dynamics, the total power consumption dropped by 12%. This operational tweak required minimal investment and yielded a return on investment (ROI) in just one month.
• Financial Impact: The project saved €7,980 annually.

Case Study: Corrugated Packaging

Similar issues were detected at a corrugated packaging facility where high energy consumption was driven by fluctuating high system pressure. The solution involved optimizing the corrugated sheet production process and setting the master controller to a lower setpoint. To ensure process safety, critical pressure alarms were configured to alert staff via SMS and email immediately if thresholds were breached.

• The Result: A 4% reduction in total energy consumption.
• Financial Impact: €2,000 in annual savings with a 1-month ROI.

Case Study: DC Motor Production

A DC motor production plant struggled with fluctuating high pressure in their production hall.

• The Fix: The team optimized the pressure setpoint of a newly acquired flow controller to lower production costs. They slowly reduced the header pressure while persistently monitoring the data.
• The Result: Pressure was reduced from 6.9 to 6.5 bar(g), leading to a 5% reduction in energy consumption.
• Financial Impact: €4,700 in annual energy savings with a 1-month ROI.

II. Capital Expenditure Optimization: Right-Sizing Equipment

Replacing aging equipment is often a knee-jerk reaction: a 110 kW compressor breaks, so it is replaced with another 110 kW unit. Data proves this is often a costly mistake.

Case Study: Beverage Company (Coca-Cola Croatia)

This facility operated three identical 110 kW fixed-speed oil-free compressors. When one unit failed, the initial plan was a direct replacement. However, a CALMS energy audit revealed a massive discrepancy: the actual demand profile only required a 45 kW VSD compressor, and the existing system had a very poor specific power of 0.2 kWh/m3.

• The Fix: The customer installed a 75 kW VSD unit (providing a safety buffer) and implemented permanent monitoring.
• The Result: This decision prevented unnecessary starts and loads. The new specific power dropped to 0.14 kWh/m3, a 32% reduction in energy consumption.
• Financial Impact: The project saved €15,746 per year in energy and €4,800 in maintenance, achieving a massive 566% return on investment.

III. Diagnostics: Distinguishing Control Logic from Mechanical Failure

When compressors behave erratically, operators often blame the control software. Granular data often points to a different culprit.

Case Study: Inlet Valve Failure Diagnosis

A system with two 75 kW fixed-speed units and one 75 kW VSD master-controlled unit began running a second fixed-speed compressor unnecessarily. The assumption was a master controller failure.

Using “live scope mode” with 1-second resolution, analysts discovered the control system was actually sending the correct signals. The lead compressor tried to load but failed to do so for nearly two minutes due to a mechanical issue, forcing the lag compressor to start to support the pressure drop.

• The Fix: Replacing the sticking inlet valve on the lead compressor.
• The Result: This diagnosis prevented unnecessary starts, extended equipment life, and reduced energy consumption by more than 11%.
• Financial Impact: €3,400 in annual savings.

Case Study: Paper Mill Control Logic

A paper mill operating four oil-free screw compressors (132, 110, 75, and 55 kW) suffered from poor specific power.

• The Fix: The master controller was optimized with new sequences, timers, and flow profiles derived from permanent monitoring data.
• The Result: This eliminated unnecessary starts and loads, dropping specific power from 0.14 to 0.135 kWh/m3 and reducing energy consumption by 6%.
• Financial Impact: €4,200 in annual savings with a 1-month ROI.

IV. System Design: Managing Peak Demand

Process instability often stems from a mismatch between storage capacity (receivers) and compressor reaction times.

Case Study: Chemical Plant (Cinkarna)

This plant struggled with fluctuating demand caused by waste presses. The process required huge air demand for very short periods (drying for 120 seconds, removing waste for 35 seconds), which the existing 200 kW compressors and 30 m3 receivers could not handle efficiently. The rapid cycling caused water condensate in the lubricant and mechanical failures.

• The Fix: Based on simulation data, two large units were replaced with smaller 45 kW units, and an additional 10 m3 receiver was added.
• The Result: The receivers now buffer the peak demands, allowing compressors to run without excessive cycling. Energy consumption dropped by over 21%.
• Financial Impact: €3,400 in annual energy savings.

V. Technology Upgrades: Waste Water Treatment

Low-pressure applications, such as aeration in wastewater treatment, offer some of the highest potential for efficiency gains.

Case Study: Waste Water Treatment (WWT) Plant

An audit identified that the plant’s aeration process was using inefficient on-off Roots blowers.

• The Fix: The facility replaced the legacy equipment with turbo variable speed blowers.
• The Result: The upgrade reduced energy consumption by more than 27%. Beyond energy, the discharge temperature dropped by 20°C, preventing excessive water heating, and noise levels fell drastically from 105 dB to 82 dB.
• Financial Impact: Total savings amounted to €53,664 per year.

VI. The Ongoing Battle: Leak Management

Leaks are not a one-time maintenance ticket; they are a continuous deterioration of system efficiency.

Case Study: Tyre Manufacturing Plant

A major tyre manufacturer with over 2.5 MW of installed power struggled to maintain system pressure due to an excessive leak rate.

• The Fix: Implementation of an external yearly leak survey combined with an internal, year-round repair management system.
• The Result: The active management program reduced energy consumption by more than 6%.
• Financial Impact: €55,000 per year in savings achieved through leak management.

Summary of Savings

Across these varied industries, the CALMS methodology - audit, detect, solve, and monitor - consistently delivered rapid ROI.