A system first approach to compressed air energy efficiency

31 October, 2024

Compressed air systems are essential to many industrial operations, but they are also significant energy consumers, often accounting for up to 10% of a facility’s electricity costs.

Therefore, optimising the entire system for energy efficiency is crucial. In this month’s Hydraulics & Pneumatics magazine we outline the key strategies for designing a more energy-efficient compressed air system, with a view to reducing energy wastage and saving cost.

View the compressed air system holistically

A compressed air system consists of multiple components, and each element impacts the system's overall energy consumption. By focusing solely on the compressor, companies can miss out on significant energy-saving opportunities elsewhere.

A holistic approach means paying attention to areas such as air treatment, leak reduction, and the ongoing maintenance. Fixing leaks, for instance, is one of the easiest ways to save energy, as even small leaks can lead to significant energy losses over time. Additionally, adopting basic housekeeping routines and ensuring equipment is maintained correctly can result in improved system efficiency and reduced operating costs.

System design and pressure losses

One major contributor to energy inefficiency is poor system design. Pressure losses occur when the design and configuration of the system cause air to be compressed to a higher pressure than is required.

Losses can arise from undersized or incorrectly dimensioned distribution piping, as well as poorly configured purification equipment. Generating compressed air at higher pressures to overcome these losses incurs additional energy costs.

Reducing air leaks is the single most important energy saving measure a site can make, as just one 2 mm hole in the pipework could cost over £1249 per year in wasted energy.

As part of an ongoing leak test and repair programme some sites are beginning to use AI systems to analyse acoustic data from sensors to detect and locate air leaks with high precision. This provides a faster and more accurate method of leak detection and fault finding, leading to quicker repairs for improved system efficiency.

In addition, an ongoing trend towards decentralisation, with multiple smaller compressors installed closer to the point of use, is helping to reduce the energy losses associated with long piping runs and pressure drops.

Monitoring for energy insights

One of the most effective ways to identify energy-saving opportunities is through data logging. Data logging over a period of at least seven days can provide insights into the system’s demand profile and off-load running time. This helps identify when compressors are running unnecessarily or inefficiently, such as during periods of low demand when energy is consumed without generating compressed air.

BCAS also advises using energy audits or installing monitoring systems to track and manage energy usage, which helps identify inefficiencies and guides future improvements.

There is also an emerging trend which uses machine learning to predict future air demand based on historical usage patterns and external factors like production schedules. This accurate demand forecasting helps improve planning, meaning compressed air usage can be optimised to reduce unnecessary compressor idling and energy waste.

Focus on whole-life costs When purchasing compressed air systems, businesses often focus on minimising the initial capital expenditure. However, this can lock them into higher running costs over the long term.

BCAS advises that decision-makers consider the whole-life cost of equipment rather than simply the upfront price. This means factoring in energy consumption, maintenance costs, and equipment longevity to ensure that the system remains cost-effective throughout its lifecycle.

By choosing energy-efficient compressors and system components from the outset, businesses can avoid the trap of short-term savings that result in long-term inefficiency and higher operational costs.

For more information, please speak to a BCAS member who can assist in this area by emailing enquiries@bcas.org.uk or call 0207 935 2464 or visit:  www.bcas.org.uk

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