Tips for an energy efficient compressed air system
18 July 2017
Here, Andy Jones, managing director at Mattei, shares his top tips for specifying, installing and operating an air compressor
If you’re not making the most of your compressed air system, at best you could be wasting energy, and at worst operating unsafely.
Of course, your compressor must be sited and installed correctly. Air flow into the compressor needs to be unrestricted, cool, reasonably clean and free from solid and gaseous impurities. The distance between the compressor and where the compressed air is actually used can have important implications too. Pipes should also be suitably sized for the air delivery capacity of the compressors, with bends kept to an absolute minimum.
Choose an efficient model at the outset. It’s tempting to think that initial outlay for the compressor itself will be the main cost, but in reality, the electricity consumed during operation over a five-year period accounts for around 75 per cent of the total cost of ownership, including the initial capital outlay. Therefore, even if the cost of a higher efficiency machine is more, you’ll save money in the long run.
It may seem obvious, but it’s important to regularly check for leaks. In many companies, 30% of the air generated is wasted through leaks, which can prove costly over time. Check for leaks at initial installation, re-check frequently, and carry out an annual leak detection survey.
Make sure you choose the right machine for your operation. Using a variable speed compressor when a fixed speed model would be more appropriate, or vice versa, can end up wasting energy. A data logging exercise can help to decide which option is more suitable.
Keep your compressor running to the optimal standard by undertaking regular maintenance in accordance with the manufacturers’ guideline. Not only will this ensure minimum energy wastage, but it will make sure your equipment remains reliable and safe.
Specify for the appropriate air quality level. We’ve seen a recent rise in requests for ‘oil-free’ compressors to produce ‘oil-free’ compressed air, but you could be investing in costly equipment which you don’t necessarily need as this can be achieved with an oil injected compressor with the correct air treatment. Use ISO 8573-1:2010 to see what class you really need and if ‘oil-free’ air is needed then check if class one rather than class zero would be sufficient. Higher air quality specification means higher running costs, so only specify what you really need and also consider point of use air treatment for specific applications/equipment that require higher than the normal system levels.
Check you’ve specified the correct compressor for your environment. For example, noise levels should be considered to protect employees. Compressor manufacturers must state the noise levels in accordance to international standards, with the current one being EN ISO 2151:2008.
Invest in data logging and energy audits to assess your system. It’s crucial to understand how much compressed air you use, how much it costs you and whether the compressors are appropriate for your production processes. Ideally these should be carried out in accordance to the ISO11011 standard.
Where possible, recover heat and put it to use. Compressors create a large amount of heat, and in some installations, this can be utilised in the production process, to heat water or for local space heating, for example.
Always stay safe. If not used properly and sensibly, compressed air can be very dangerous, as it travels at an extremely high speed. If it hits the eyes or ears it can cause detrimental damage. Make sure anyone working with compressed air is aware of the risks, and operate as safely as possible and ensure that you have an up to date written scheme of examination for your system, as this is a legal requirement.