COMPRESSED AIR – where can you save?

Saving costs in compressed air production, distribution and use is a complex task made up of individual measures that build on or complement each other.

Each operation needs a compressor or combination suited to its compressed air demand profile. Neither fixed-speed nor variable-speed compressors can be declared more suitable without considering the pattern of consumption.

A compressor generates waste heat equivalent to around 70% of its total electrical input.

An efficient, low-investment way to use waste heat where there is demand for warm air near the compressor station.

Regular maintenance has a major impact on energy demand caused by increased pressure losses or compressor temperatures, as well as on reliability and the risk of failure. A clogged oil separator can add 0.5 bar of pressure drop, for example, increasing energy consumption by 3.5%.

New air treatment technologies offer substantial savings: cycling refrigerated dryers, variable-speed dryers, and modern adsorption dryers with suitable heatless or heated regeneration. Advanced controls can cut refrigerated dryer energy consumption by 50%. Adsorption dryers can also reduce regeneration air losses from 20% of total air production to virtually zero.

Clogged filters can significantly increase average pressure and total compressed air costs. Monitoring filter differential pressure in real time allows elements to be changed before clogging causes excessive pressure loss. A new filter typically drops around 0.05–0.1 bar. As it clogs, this can rise to 0.4 bar, adding 2.5% to energy consumption per filter.

More about differential pressure monitoring at www.airman.info

Condensate can be drained in ways that prevent unwanted compressed air loss. A clogged drain that continuously blows air can waste 8–15 m³/h.

Air receiver selection is part of correctly designing the entire compressor station to avoid pressure fluctuations and unnecessary compressor switching.

To maintain low production costs over time, monitor electricity consumption and compressed air parameters: pressures, flows, pressure dew points, differential pressures and temperatures.

More about monitoring compressed air economics at www.airman.info

Master control can deliver significant savings by reducing average pressure and the proportion of unloaded running. Typical savings are 3–10% of the original costs.

More about predictive master compressor control at www.airman.info

Even an optimised station producing air efficiently cannot guarantee low costs for pneumatic work if the distribution system leaks. Regular detection and reduction of leaks are essential. In normal industrial operations, losses of 30% of total air production are not unusual.

Pipe size, condition and material have a major effect on air quality and economical operation. Undersized or corroded pipes cause pressure losses that must be offset by higher compressor energy consumption. Neglected pipework can increase costs by more than 10%.

Motorised ball valves can automatically close unused air branches on a schedule, preventing unwanted leaks while they are not in use.

More about automated pipework branch isolation at www.airman.info

Compressed air systems continually evolve, even without major modifications. To keep production, distribution and consumption costs low over time, carry out regular audits to identify savings, spare capacity and other opportunities to optimise the whole system.

Would you like to learn more about savings? Attend our seminar “Economics of Compressed Air“.