Energy efficiency of compressed-air equipment
Generating and supplying compressed air is a very energy-intensive activity. Improving the energy efficiency of compressed-air equipment by implementing concrete measures can save more than 30 % of the total energy used.
The efficiency of such compressed air systems can be improved through simple changes, e. g. by adjusting the system pressure according to the actual demand as well as the required quality. Carbon Trust recommends the following efficiency measures:
Reduce pressure: Compressed air is often generated at the compressor's maximum pressure (often 7 bar, 100 psi). Reducing pressure by 10 % can lead to 5 % energy savings. Make small, incremental reductions, checking that operations are not affected.
Identify and fix leaks: If you do have leaks, locate them by listening for them out of hours. Or hire ultrasonic leak detection equipment, which is the most convenient way of checking for leaks, but may require specialist operation. Even a tiny leak (just 3 mm) could cost you more than € 800 a year in wasted energy, so carry out a 'no-load' test to check for leaks.
Check that compressed air is really required: Compressed air is expensive to run, and yet cheaper options exist for certain jobs. Educate your staff not to allow compressed air to vent into the atmosphere (e.g. cleaning benches). If possible, don't use it for drying or ventilation. A usage policy that suggests safe and easy alternatives to compressed air will help your staff save energy. Unless there is a specific requirement (e.g. an explosion risk) do not use air-driven motors for providing motion. Where possible, use an electrically powered motor instead.
See if compressed air could be delivered more efficiently: If compressed air is appropriate for the job, could it be delivered more efficiently? For example, many blow guns are simply open-ended pipes: fitting a venturi-type nozzle can use 30 % less compressed air, and, by making the operation much quieter, improve the working environment.
Switch off compressors when not in use: An idling compressor uses around 40 % of its full load. Where appropriate, turn compressors off when they're not being used (for example during tea breaks, and certainly overnight).
Don't over-treat air: Treating air to remove dirt, water and oil is necessary but uses lots of energy. Treat the application rather than the whole system.
Additional measures which save energy and can quickly pay for themselves include compressors with high-efficiency motors or variable-speed drives. Also (re)using the exhaust heat of compressors improves the overall efficiency performance.