Mastering your compressed air system for optimum efficiency

In a typical plant multiple compressors rather than one single unit will provide the total air flow required. A compressed air system with multiple compressors may be inefficient if for example, each compressor unit is individually controlled by only its own control settings. Energy is also wasted in this scenario because: 

• system pressure will likely be inconsistent 
• you may end up running more compressors than is actually necessary to meet the actual demand for compressed air at any given time 
• the compressors are likely to be operating at higher pressures than required 
• there may be excessive idling of the compressors. 

All of the above also have the likely knock-on effect of increased maintenance requirements and of course the associated costs that come with this. 

So what is a compressor controller? Fundamentally there are two types: 

1. Individual compressor control; this is the controller you will see on an individual compressor unit. Advanced controllers will provide important maintenance information which ensures both the safe and efficient running of the compressor. They will also provide the ability to connect via e.g. Ethernet to external services that can remotely control and monitor the compressor. 
2. Master control; this is a separate controller that links and orchestrates the operation of all of the compressors and ancillary equipment that make up a compressed air system for optimum efficiency and cost effectiveness. 

In basic terms a master controller has the ability to improve the pressure stability and reliability of all equipment within a compressed air system by turning individual compressor units on and off when required in order to meet the specific compressed air demanded at any one time. This improves specific performance and balances compressor load hours resulting in optimum maintenance scheduling. Overall this leads to optimised energy efficiency.

Advanced master controllers can manage multiple compressors of different sizes as well as select the right mix of compressors to meet the current demand for compressed air whilst at the same time reducing energy consumption in 3 key ways:

1. By reducing compressor run and idling times; for every hour of operation a typical compressor will accumulate several minutes of unnecessary run and idle time. By operating only the compressor units required to meet the current compressed air demand, advanced master controllers can save anywhere from 2 to 10 % in energy costs. At the same time compressor starts and switching losses are reduced. Idle time in part-load conditions is also reduced as the advanced master controller will determine which compressor units have the best specific performance and therefore maximise full-load operation. 
2. By improving pressure performance; unlike outdated sequencers that use cascading pressure controls with wide pressure bands, advanced master controllers are able to recognise changes in air pressure quickly and accurately and can therefore maintain tighter pressure control. Advanced master controllers also allow lower average system pressures. Along with better air pressure stability approx. 10% energy savings can be commonly achieved using this approach. 
3. By reducing artificial demand and leaks; artificial demand is created where users set the systems air pressure higher than actually needed to compensate for e.g. pressure drop and potential air leaks. The result – energy is wasted. With advanced adaptive master controllers the user can reduce the pressure while at the same time avoiding under pressurising equipment and tools. Being able to operate at a lower pressure will reduce both artificial demand and leak losses. As a rule of thumb every 0.15 bar reduction in compressor pressure will result in a 1% reduction in power consumption. For example, an operating pressure reduction from 8.5 bar to 7 bar would reduce the flow rate through a 6 mm orifice from 3.5 m³/min to 3 m³/min. This would result in almost 20% in savings! Depending on system size, even a 5% reduction in pressure would result in substantial savings. 

When it comes to operating an energy efficient compressed air system, today’s sophisticated and advanced master controllers gives compressed air users unparalleled access to optimal performance and reliability – perfectly matching compressed air supply to demand for optimum energy efficiency. 

Reference: Perry, W Camber, M – Kaeser Compressors (October 2014): Using master controls to improve the performance and efficiency of industrial air compressors

Is a master controller the right option for your compressed air system? Why not speak with one of our compressed air experts today and find out! Phone 0800 447 820 or fill in the form below and we will contact you.