While analysing the electricity consumption of a compressed-air system in a manufacturing facility, OMS24 Zrt. found that the compressors were regularly starting even outside production hours, when there should theoretically have been no demand for compressed air.
The measurement data showed that the machines were compensating for pressure losses in the pipework — repeatedly replacing air that was escaping from the system.
Based on our analysis, eliminating these losses could have reduced electricity consumption by approximately 1,000 kWh per month.
The starting point
Compressed air at the manufacturing facility was supplied by several compressors.
During production, the system was naturally a significant consumer of electricity. There is nothing unusual about that: generating compressed air requires energy.
The more important question was:
What happens when production has stopped and there is no compressed-air demand?
The submetering data provided the answer.
What did we measure?
We continuously monitored the electrical power consumption of the compressors.
The measurement profile clearly distinguished production periods from times when manufacturing had already stopped.
Without compressed-air demand, we would have expected the compressors to remain switched off for extended periods.
That was not what happened.
The machines continued to start regularly outside production hours.
What did submetering reveal?
Hidden compressor consumption revealed by submetering – OMS24 Zrt.
The most important parts of the chart are the periods outside production hours.
Even during these periods, the compressors did not remain switched off. Instead, they restarted at regular intervals.
Yet there was no production-related compressed-air demand that would have justified this operation.
This repeated behaviour was an important signal:
compressed air was being lost somewhere in the system even when there should have been no consumption.
In this case, electricity measurement therefore indirectly made losses in the compressed-air network visible.
What was causing the unnecessary consumption?
The measurement data indicated that, outside production hours, the compressors were compensating for pressure losses caused by leaks in the compressed-air pipework.
Air slowly escaped from the system.
The pressure dropped.
The compressor started, restored the pressure and then stopped.
After a while, the same cycle began again.
In other words, electricity was being used to produce compressed air that performed no useful production work.
What could have been changed?
The solution in this case would not have required purchasing a new compressor or making a major energy-efficiency investment.
The appropriate action would have been to identify and repair the leakage points in the compressed-air network.
Eliminating the leaks would have reduced pressure losses outside production hours, which in turn would have reduced the number of unnecessary compressor starts.
Based on the original analysis, this could have resulted in an electricity consumption reduction of approximately 1,000 kWh per month.
The result
In this case, submetering clearly identified both the problem and its energy impact:
approximately 1,000 kWh/month potential saving
However, the client ultimately decided not to proceed with repairing the network leaks.
For this reason, it is important to distinguish this case from our other case studies:
this was not a realised saving, but a saving opportunity identified through measurement data.
What does this case show?
The most expensive energy is often the energy that produces no useful work at all.
A compressed-air system can operate for years while losses remain invisible.
The compressors start and stop, the required pressure is available, and from the outside everything may appear to be working normally.
The consumption profile, however, also reveals what happens when theoretically nothing should be happening.
This is one of the greatest values of submetering: it makes hidden operational losses visible.
What is consuming energy at your site when production has already stopped?
Submetering can help separate and identify out-of-hours, standby and unnecessary energy consumption.