Simple steps to compressed air energy savings

While both environmental and financial targets are driving operators to reduce their site’s overall electricity bill, many simple energy-saving measures related to their compressed air system can be overlooked. 

As the UK’s trade body representing compressed air system manufacturers, distributors, and end users, the British Compressed Air Society (BCAS) advises regularly on the numerous ways that customers can improve the efficiency of their compressed air system.

Change behaviours, specify correctly 
Many actions 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. 

Manufacturers that are considering upgrading their existing compressed air system should always consult an expert first. BCAS members can advise on the best equipment and system for the specific requirements. This could include incorporating fixed and variable-speed drives or a combination of both as well as efficient downstream equipment. Where suitable, sophisticated control systems can help proactively manage the supply of air. 

Fix leaks to save money
Reducing air leaks is the single most important energy saving measure that the industry can take. An ongoing leak test and repair programme will save considerable cost. Just one 3mm hole could cost over £600 a year in wasted energy. A leak survey can help you size the issue – and to tackle the largest leaks first. 

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. A compressed air system assessment in line with ISO 11011:2013 can be a great place to start.

Control better, manage air downstream
Reducing pressure at the point of use, switching off compressors when there is no demand for air and installing energy management systems can all help to identify unnecessary wastage and enable appropriate action to be taken. 

Treating air to remove dirt, water and oil is necessary but can use a lot of energy. The process is 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. 

Recover heat, improve maintenance
As much as 95 per cent of the energy consumed by a compressor is converted to heat and, unless captured, will be wasted to the atmosphere. Many manufacturers offer heat recovery systems, which can often be retrofitted. This allows operators to recycle this excess heat; re-directing the hot oil to an oil-to-water heat exchanger.
Low cost, regular maintenance will help retain low leak rates and reliability of equipment. Manufacturers should also consider a policy that specifies that energy efficient options are purchased when replacing all equipment – whether it is a basic drain valve, the use of genuine spare parts through to the actual compressor unit itself. 

Vanda Jones is executive director of BCAS