Manufacturers are facing unprecedented challenges to stem rocketing energy costs and reduce carbon emissions. As the so-called “fourth utility” of manufacturing, compressed air systems can frequently be the cause of wasted energy. Yet despite offering possibly the greatest opportunity for belt tightening, opportunities for savings are all too easily overlooked. Compressed air accounts for 10% of energy use in a typical manufacturing operation, rising to 30% in heavy use industries such as food and beverage, automotive, plastic products and pharmaceuticals, according to the British Compressed Air Society1.
Hissing Sound
Many engineers are familiar with the experience of walking onto a shop floor in the early morning, before the machines start up and the workers arrive, and an eerie sound of hissing pervades the silence. That hissing is the unmistakable sound of compressed air leaks. It’s also the sound of your company’s cash quite literally disappearing into thin air.
It’s estimated that manufacturers waste around 30% of the compressed air they generate.2 But, until now, operators have only been able to get a limited grasp on how much energy is actually being used by their compressed air systems, and where the problems lie. Tracking down and fixing leaks can be a laborious, hit and miss affair.
Even with a modern energy management system in place, a maintenance team may only survey the plant every three or six months. External companies may be brought in to conduct periodic spot check audits. The data provided is reliable only for one moment in time, and very little can be gleaned from it about any trends or patterns. Do some machines use more compressed air than others, when, and why? How can compressed air energy reduction best be targeted across entire processes and production halls to maximise results?
‘Bolt-on’ transparency
By feeding the data from accurate sensing instruments into new cloudbased monitoring systems, sensor manufacturers like SICK are introducing digital services that are easy to ‘bolt on’ to the existing production process with minimal set-up and no programming. The results can be remarkably revealing, and SICK customers have been surprised by the discoveries they can make. Darren Pratt, Industrial Instrumentation Product Manager for SICK UK highlights that his company has developed a turnkey solution specifically for continuous compressed air energy management. The SICK FTMg is a multifunctional flow sensor that enables the measurement of live values for compressed air energy in kWh. He explains that using data from SICK FTMg flow meters strategically positioned around a plant, and usually close to machines or cells, a wealth of both realtime and historic data about compressed air usage, including energy consumption, is available.
He adds that data from the FTMg flow meter is made transparent through graphics presented in the SICK FTMg Monitoring App. With the click of a button, users can start visualising all this continuous compressed air data in a way that is easy to use and interpret. As well as values for pressure, temperature, flow velocity, mass flow rate and volumetric flow rate in real time, the system provides totals for energy use, volume and mass over a pre-defined period.
The user-friendly dashboard makes it easy to interpret data to detect leaks or overconsumption and to look for changes and trends. Email alerts can be set up for maintenance reminders or to give pre-defined warnings with job recommendations, for example, when data strays beyond predefined limits. Users can drill down to identify costs, for example for individual production centres or by shift.
Unexpected Insights
Pratt says we are already seeing how early adopters of the FTMg Monitoring App are gaining unexpected insights. They have been able, for example, to make start-up and shutdown management of processes and machines more efficient, improve compressor control, and manage peak loads.
By tracking consumption over time, Pratt explains that losses are easier to spot and correct. For example, he highlights that energy waste is clear if the compressed air usage graph does not baseline close to zero at weekends. Is there a surge in power usage on a Monday morning when machines are turned on? Then, perhaps, a more efficient power-up sequence could be adopted to prevent overloading the compressor.
The system makes it possible to monitor energy usage close to the machine cells where the compressed air is being used. Armed with additional information, production teams can pose specific questions: How much air is cell number 1 using, compared to cell number 2? If cell no 3 uses a lot more compressed air energy, then keep it offline as long as possible. How much compressed air energy is needed to produce one type of component compared to another?
As well as enabling resources to be used more sustainably, the data insights support better operational efficiency and help achieve reduced carbon targets. The information can contribute towards ISO50001 Energy Management certification, or compliance with the UK Government’s Energy Saving Opportunity Scheme (ESOS).
The SICK FTMg, which stands for Flow Thermal Meter for inert gases, uses the dynamic calorimetric principle for precision measurement, enabling it to detect even the smallest changes reliably. Up to eight FTMG flow meters can be configured via each SICK Smart Services Gateway, which collects data, aggregates and encrypts it before sending it securely via the customer’s own IT infrastructure through a firewall to the SICK cloud. Alternatively, it is possible to by-pass the IT infrastructure by using mobile communications over 3G or 4G. Individuals then have access through a personal SICK ID from any device with a web browser.
Pratt adds that SICK also offers alternatives for customers who do not require the FTMg Monitoring App. For customers wishing to integrate SICK FTMg flow meters into their own IT systems, one or more devices can be used with an IIoT gateway, such as the TDC-E from SICK, for data pre-processing and integration into customer-specific MES, cloud or energy management systems.
Measurable payback
Wasted compressed air adds up to a huge energy costs and carbon emissions that are easily fixed.
According to the Carbon Trust, UK industry uses over 10TWh of electricity a year to compress air 2 equivalent to almost 1.5 power stations. It’s not just the wasted energy, the usage equates to 5 million tonnes of CO2 emitted into the atmosphere.
Understanding the importance of compressed air energy efficiency as part of total cost of ownership demonstrates the benefits of investment in efficient in-line, real time instrumentation – especially when combined with the data transparency that is unlocked by new digital services. The payback could be instantly measurable.
1. British Compressed Air Society Reducing Energy Consumption from Compressed Air Usage
2. Carbon Trust, Compressed air, Opportunities for Business (2012)
https://www.linkedin.com/showcase/sick-uk-ltd/
