As a rule of thumb for most compressors, a set point reduction of 1 bar will lead to a 7% saving in electricity. The pressure settings of the compressor should be adjusted until the lowest pressure can be reached and the pressure band reduced without affecting the application.
For centralised systems utilising multiple compressors, by using a central controller such as Atlas Copco’s ES controller, the network can be set to run within a narrow pressure band which ensures that the compressed air network matches your precise needs. The ES can also allow you to manually or automatically create two different pressure bands to optimise energy use within different periods, drastically reducing energy costs at low-use times.
Leakages are the biggest source of energy waste in compressed air systems, with a leakage point as small as 5mm costing an estimated £3,800 in wasted energy over the course of a year. In one recent project undertaken by Atlas Copco, a leakage detection programme instigated across a UK vehicle manufacturing plant identified leaks costing £102,000 a year in lost energy. A similar programme conducted over the course of three days by Atlas Copco’s AIRScan team at a confectionery manufacturer, pinpointed £31,000 worth of leaks that were subsequently repaired.
Process leaks are another reason for overspending on energy and these can be corrected by replacing production line equipment, for example, establishing greater control of pressure or shutting down systems when they are not in use.
Most production processes require different levels of demand in different periods, which may mean that the compressor is running off-load or idle (not producing any compressed air) for long periods of time. Great savings can be made if a fixed speed compressor can be replaced by a variable speed drive unit as it only produces compressed air as and when required. This also minimises offload running of the compressor, which is known to waste energy. (A VSD compressor saves an average 35% energy and a VSD+ unit can save as much as 50% compared to a fixed speed unit, even at full load).
As a fixed speed compressor has a fixed amount of motor starts an hour, the compressor runs offload for a set time which limits the number of motor starts to ensure overheating of the motor does not occur. As a VSD unit ramps up and down in a controlled fashion, the maximum number of starts and stops per hour may be increased, and it also avoids peaks in current when starting.
Book a FREE compressed air audit or a more comprehensive Airscan to see the energy saving potential within your production process. An analysis of compressed air usage patterns will show where the system could be improved or optimised for greater efficiency, identify opportunities for eliminating leaks and other wasteful practices, artificial demand and inappropriate use.
According to the Carbon Trust, a business can reduce its annual energy costs by 20% through improving energy efficiency and energy management, which makes it all the more important for those companies who completed an ESOS (Energy Savings Opportunity Scheme) audit to take the next step and turn the recommendations into real-life energy savings.
Atlas Copco can of course advise on the compressed air recommendations. Alternatively, check out the government's guide which aims to help companies make the most of the energy savings opportunities identified by ESOS.
The best way of taking care of your compressed air availability is by taking the best care of your compressed air equipment. This means investing in regular preventative maintenance, which will sustain the efficiency that you have gained by purchasing a new compressor, or improve the performance of an older unit.
Whether you prefer to purchase spare parts only and perform maintenance in-house, sign up to a planned maintenance programme at pre-determined intervals from the manufacturer or approved distributor, or choose a total responsibility package that covers breakdowns and leaves no room for surprises, the main thing to remember is that reduced compressor performance is not inevitable as the machine gets older. Regular servicing will improve your equipment uptime and energy efficiency – and the opposite could lead to more downtime and increased energy consumption.
Whether you prefer a preventive maintenance plan or a fixed price service make sure your compressed air equipment is in safe hands.