The Malta Independent 7 May 2021, Friday

Untangling the inefficiencies of compressed air systems

Thursday, 17 September 2020, 13:54 Last update: about 9 months ago
Dr Ing. Paul Refalo, Kyle Abela, Dr Ing. Emmanuel Francalanza
Dr Ing. Paul Refalo, Kyle Abela, Dr Ing. Emmanuel Francalanza

The Department of Industrial and Manufacturing Engineering at the University of Malta is playing a crucial role in improving the sustainability of the Maltese industrial and manufacturing sector by identifying common applications where energy is wasted.

One such application is the use of compressed air systems which are critical for numerous manufacturing companies. With an increase in awareness related to sustainability and carbon footprints, local industries and companies are becoming increasingly aware of the financial and environmental penalties linked with inefficient compressed air systems.


An ongoing research study which was initiated in 2017 by Dr Ing. Paul Refalo and Dr Ing. Emmanuel Francalanza in collaboration with AIM Enterprises Ltd has resulted in a number of scientific publications [1, 2]. It has also led to the postgraduate research study of Mr Kyle Abela which involved the identification and testing of advanced monitoring techniques within industrial pneumatic applications. With the financial backing of the Tertiary Education Scholarship Scheme (TESS) of 2018, Abela worked on the initial version of a customised compressed air system in the form of a test bed and upgraded it to include the latest sensors, communication protocols and control equipment that is available in the pneumatic and compressed air market.

The improved equipment was set up such that a data monitoring system could detect and quantify losses from equipment on the demand side of a compressed air system. As a result of the scale and complexity that is typically associated with compressed air systems, monitoring equipment is typically installed close to the compressor at the supply side rather than the demand side. However, literature studies show that 50-70% of all improvement opportunities within these systems are attributable solely to demand side waste which ultimately amalgamate in the form of increased maintenance costs and electrical bills.

Through the use of high-end sensors, the study showed that the operational changes within compressed air systems are governed by variances within the fluid dynamic behaviour of the compressed air. The results were generated in the form of diagnostics according to each test condition which allowed the research team to identify and locate leaks at the demand side. Leaks are the most common form of waste within compressed air systems and very often aggravate and manifest into other issues such as artificial demand and/or break downs. The highly configurable test-bed was setup such that flow rate and pressure drop data was logged across different leakages of known diameters.

The literature showed that as a result of the lack of data monitoring that is available within compressed air systems, losses such as leaks easily spiral out of control. Furthermore, through the fluid dynamic diagnostics of the study it was also concluded that within large industrial compressed air systems, common compressed air parameters and key performance indicators such as pressure drops and flow rate changes become increasingly unreliable. This is due to the fact that sensors are selected in accordance to the consumption of each system where high consuming systems would require sensors with a subpar sensor accuracy. For this reason, minute losses from leaks could easily go unnoticed and are only corrected when the cumulative and unsustainable effects of multiple leaks are observed in a compressed air system.

Ultimately, this study has paved the way towards using compressed air data to identify and locate misused energy sources. Future research is set to elaborate further on the way with which compressed air information is gathered, interpreted and presented. 

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