Changing behaviour to help cut energy consumption
20 November 2020
Vanda Jones, Executive Director for the British Compressed Air Society (BCAS) takes you through some of the key factors when embarking on a compressed air energy reduction programme – focusing specifically on areas of behavioural change
Many compressed air system improvements will require elements of maintenance or equipment/system upgrade, but the human element should not be overlooked. Operators can make substantial efficiency improvements by implementing new processes and encouraging staff to use compressed air more efficiently and safely.
Take a system approach
A compressed air system is just that; a system, and every element of it impacts on its energy consumption. When discussing efficiency and the potential savings that could be realised, it is important to take a full, system approach. – from generation to air treatment to distribution and finally, the point of use.
An ideal place to start is to identify some of the key areas where valuable compressed air can be wasted by processes or people downstream of the compressor.
For example, if you install the most efficient compressor available, but connect it to a system with a 30 per cent leak rate, then all the benefits are lost. Customers should aim to improve the overall system efficiency. Efficiency in the generation of compressed air is one aspect but targeting avoidable waste in the system is even more important.
Detect and fix leaks
Reducing air leaks can have a big impact on overall system efficiency. Leak rates in industrial systems are typically between 20 and 40 per cent, meaning the compressor has to work harder, and therefore consume more energy, to compensate for the pressure loss.
A tiny leak of just three millimetres can cost more than £700 a year in wasted energy, but an out-of-hours survey can identify leaks easily. Simply walk the site listening for leaks.
The location can then be confirmed by using an ultrasonic leak detector, a leak detection spray or even a soap solution brushed on to pipe fittings.
Even when off-load, compressors can consume up to 70 per cent of their full load power, so switch off units overnight where there is no demand for air. Operators should check the time switch settings regularly to ensure they are optimising running hours as this can also help to reduce maintenance costs.
Where appropriate, energy management systems should be installed to turn compressors off when they are not being.
Review compressed air usage
Compressed air is energy intensive to run, and cheaper options exist for certain jobs. For example, there may be more energy-efficient alternatives for drying and ventilation. However, for applications where there are risks of explosion or electrical interference, compressed air remains the best option.
Train and involve staff
Simple awareness sessions to advise staff about the costs and safe use of compressed air can be highly effective. For example, not allowing benches or equipment to be cleaned down with compressed air will save a significant amount of air being vented into the atmosphere.
Don't over treat air
Treating air to remove dirt, water and oil is necessary but can use a lot of energy. Most processes are likely to only need a proportion of the compressed air to be treated to a very high purity. In these cases, excellent savings are achievable be treating all the generated air to the minimum acceptable level and improving the purity (quality) to the desired level at the usage point.
BCAS’s Reducing Energy Consumption from Compressed Air Usage’ best practice guide
BCAS’s ‘The Filtration and Drying of Compressed Air’ best practice guide