Energy accounts for roughly 70–80% of the lifetime cost of a compressed air system, so an energy audit is the fastest way to cut operating cost. The audit measures how much air is made, where it goes and how much is wasted.
What to measure
- Leakage rate by pressurising the system after hours and timing the pressure fall
- System pressure against the minimum the process actually needs
- Load and unload profile of each compressor
- Pressure drop across dryers, filters and pipework
- Specific power of each machine in kW per m³/min
Fast wins
Leaks commonly waste 20–30% of output and are the cheapest loss to fix. Lowering the pressure setpoint by 1 bar cuts energy use by about 7%. Sequencing compressors with a central controller eliminates the waste of several machines running at part load simultaneously.
Heat recovery
Most of the electrical energy a compressor consumes becomes heat. Recovering that heat for space or water heating turns a cost into a useful by-product and can pay for itself within one to two years.