When plant managers look to reduce compressed air energy costs, they usually start with an ultrasonic leak survey. While fixing leaks offers excellent ROI, it only scratches the surface. Deep-seated engineering and system design flaws often waste significantly more money than leaks alone.

01 | Distribution

High Internal Pipe Velocities (IPV) and Frictional Losses

As manufacturing plants expand, they often add new compressors without upgrading their original piping infrastructure. This leads to undersized pipelines trying to carry massive volumes of air.

Industry best practice dictates that Internal Pipe Velocities (IPV) should be:

  • < 6m/s in the compressor room
  • < 10m/s in main distribution lines
  • < 15m/s in drop-offs to equipment
In a recent audit, we found a plant pushing air from two 100kW compressors through a standard 3" galvanised pipe, creating IPVs of ±12.5m/s. This excessive velocity creates massive internal frictional pressure losses. The result? Backpressure builds up at the compressor, tricking the pressure sensors into unloading the compressor prematurely while the factory floor is still starved for air.

02 | Demand Profile

The Danger of "Inappropriate Use"

Compressed air is incredibly expensive to generate, yet it is frequently used for tasks that could be accomplished much cheaper. We refer to this as inappropriate use.

A prime example is using compressed air to generate a venturi vacuum (such as a Piab system) for pneumatic transport of materials like food products or packaging. In one assessment, we discovered a single venturi vacuum system was consuming ±20% of the entire plant's compressed air capacity, making it a Significant Energy User (SEU). By simply replacing this setup with a dedicated electric blower/vacuum, the plant could drastically reduce its compressed air base load and switch off an entire 132kW compressor.

03 | Generation

Cooling Loop Failures and Oil Degradation

Large water-cooled compressors rely entirely on the plant's chilled water circuit to remove the intense heat of compression. When these cooling loops are inadequate, the consequences are disastrous.

We frequently investigate oil-flooded screw compressors experiencing rapid oil degradation. When the chilled water circuit fails to remove the heat, the compressor oil degrades and literally vanishes from internal components. When the compressor is switched off, the lack of lubrication prevents it from restarting, causing massive production downtime and severely damaging the air-end. Before buying new compressors, the cooling infrastructure must be validated.

04 | Power Quality

VSD Failures and Poor Power Factor

Variable Speed Drive (VSD) compressors are excellent for energy savings—until poor onsite power quality destroys them. High voltage spikes, lack of active harmonic filters, or heavy dust loads drawn into the VSD cooling fans can cause premature failure.

When VSDs fail, some plants attempt to rewire the motor as a fixed-speed unit to save on repair costs. In our audits, we've logged these modified units drawing very low kW but excessively high kVA, resulting in a disastrous Power Factor of around 0.6. The plant pays heavily for inefficient energy draw, while the compressor itself operates at a dismal 43% efficiency.

The Bottom Line: An efficient system at altitude should operate near ±7.8kW/m³/min. If you don't know your exact generation efficiency, pipe velocity, or leakage cost, you are operating in the dark.