Sustainable compressed air energy savings

As business becomes more aware of its carbon impact and finding ways to reduce its carbon footprint, Boge provides details on a tried and tested four-step approach to energy management for compressed air users. Its approach not only benchmarks an existing system but also provides for continual assessment and validation of the compressed air system.

Step 1: Audit

Establish the benchmark, a system must be comprehensively audited by evaluating generation, treatment, distribution and process usage.

The generation evaluation may include identifying factors such as the numbers of compressors being used to meet the demand, the quality of maintenance and so on.

Even seemingly small factors could be unnecessarily heightening energy costs. A common cause of poor efficiency is the use of spurious spare parts.

Not using the manufacturer’s original parts, for example rotary screw elements, can alter compressor specification and efficiency.

Leakage is another area that creates unnecessary energy costs that can be assessed within the audit. An ultrasonic leak detector can detect precisely where leaks are. It is worth remembering that just one 3 mm leaking hole costs roughly 3 kW, which equates to over $4000 a year (depending on the local kW power cost).

Step 2: Optimise

Once an audit is completed, the whole compressed air system can be optimised to reduce, and if possible eradicate, the identified energy waste and misuse. In many cases the recommended changes will only incur low costs - if any.

Step 3: Post-Audit

After the whole system has been optimised, the system efficiency (kW/m³) should be compared with the original benchmark in order to validate changes that have been implemented. At the same time it is possible to verify the ‘payback time’ for any investment that was implemented to create the ongoing energy savings.

Step 4: Continual improvement

As system dynamics change, so will the demand for compressed air. Ongoing evaluation is therefore vital in order to maintain an energy-efficient compressed air system.

Where applicable, there are significant savings to be made by integrating low-carbon technologies, from upgrading to a frequency-controlled screw compressor to implementing an energy management control system. Quantifiable evidence from energy audits can be provided to justify the investment into such technologies.

An optimised compressed air system will create energy savings that will impact on electricity bills and inevitably the bottom line. Additionally, many consumers now expect their suppliers to be environmentally conscious, therefore actively implementing methods and low carbon technologies to reduce the carbon impact to enhance the corporate image.

Most importantly, the end user needs to ask themselves what the result would be of doing nothing. Yes, the system will still work. But, it would work inefficiently, consume unnecessary energy and it will inevitably require more service upkeep. The result - unnecessary cost to the business.