What are compressor controllers?
The majority of compressors will come with an integrated controller which controls that individual unit. These controllers allow for the safe and efficient management of the unit in question and usually provide key data such as; the internal pressure, the airend discharge temperature, service hours and so forth. They are highly advantageous in alerting the user to any faults and when maintenance is required. Advanced integrated controllers will also have the functionality to notify the end user of key information remotely, sending it to, for example, an email address or as an SMS.
For optimum energy efficiency of the entire compressed air system, a master controller can be introduced. A master controller is a control system which manages all of the compressors and the associated ancillary equipment - such as filters and dryers - within a compressed air system. At its basic level, a master controller switches each of the compressor units in the system on and off as required to most efficiently match the compressed air supply to the demand.
Why should I incorporate a master controller?
If you operate multiple compressors without a master controller, it is likely that this will be creating unnecessary costs and inefficiencies within your compressed air system.
When compressors in a multiple system run independently of each other, it is highly probable that the system pressure will be unstable. This can lead to excessive idling and operating compressors at higher pressures than necessary. Such factors will contribute to energy being wasted.
In addition, there will be more wear and tear to compressors which experience e.g. excessive motor starts, leading to increased maintenance requirements.
How can an advanced master controller reduce energy consumption?
Advanced master controllers can deliver an advanced energy management solution. By managing multiple compressors and selecting the right combination of compressors to meet the current demand requirements, an advanced master controller can reduce energy consumption thereby improving the performance and efficiency of a compressed air system in three ways:
- Reduce compressor operating and idling time; did you realise that for every hour of operation a typical compressor will amass several minutes of excessive run and idle time? This creates unnecessary cost to a business that could be significantly reduced by managing the compressor with an advanced master controller. With an advanced master controller, only the compressor or combination of compressors which have the best specific performance are selected. This maximises full-load operation and reduces idling time in part-load conditions.
In addition, by only operating the compressor units required to meet the compressed air demanded, compressor starts and switching losses are reduced. Together this contributes to estimated energy cost savings of between 2% and 10%
- Reduce artificial demand and leaks; it is often the case that a user will set the compressed air systems pressure higher than actually needed to compensate for artificial demand. Artificial demand is air demand created by e.g. compressed air leaks and pressure drops, and not the actual end uses of the compressed air. Artificial demand results in wasted energy.
With an advanced master controller, the user can reduce the pressure whilst avoiding the risk of under-pressurising associated tools and equipment. And, operating at lower pressures reduces artificial demand as well as losses associated with air leaks. Depending on the systems size, even a 5% reduction in pressure would yield substantial savings.
- Improve pressure performance; tighter pressure control can be maintained with advanced master controllers which will quickly and accurately recognise changes in air pressure. In contrast, outdated sequencers use 'cascading' pressure controls which have wide pressure bands. More advanced and current master controllers allow lower average system pressures. This approach, in tandem with better air pressure stability, can generate energy savings of around 10%
With an advanced master controller it is possible to improve the pressure stability and overall reliability of a compressed air system thereby keeping associated energy consumption to a minimum. In addition, improving the specific performance and optimally balancing the compressor load of all the compressors in the system with a master controller, will also reduce wear and tear to the compressors.
For further reading on this topic download the Kaeser Compressors Inc. whitepaper (link below).
Reference: Perry, W. Camber, M. Using Master Controls to Improve the Performance and Efficiency of Industrial Air Compressors Kaeser Compressors Inc.