Those who have been following my recent blogs will have noticed the topics I’ve focused on to date look at the ways in which improved energy efficiency and reduced costs can be achieved. In addition to those already covered, there’s another way of achieving further energy and cost savings: using an intelligent controller when operating two or more compressors.
Modern electronic controllers provide much greater energy saving in two ways:
- They maintain pressure to a much narrower range
- They select the best combination of compressors to meet demand more efficiently
The first method, maintaining pressure to a much narrower range, is achieved by constantly monitoring the pressure using an accurate pressure transducer, which predicts when a compressor should be switched on or off. This is based on the rate of change of the system pressure. Using this method, the pressure band can be maintained to within 0.2 bar – which is the ideal zone to be targeting for efficient operation.
The second technique, which is to predict and select the best combination of compressors to meet demand, is especially effective if using a combination of fixed speed and variable speed machines, since it minimises off-load and part-load running of the compressors. Instead, compressors are producing compressed air only when it is required, therefore eliminating unnecessary energy usage.
The savings that multi pressure systems can make shouldn’t be underestimated. For every 1 bar saved on pressure, 7% can be saved on electrical running costs. And if there’s limited flow of higher pressure is needed, booster compressors can easily be integrated.
Electronic sequential controllers, which control multiple compressors around a single set pressure, can also make compressors available to match demand as closely as possible. For example, instead of using a 100kW compressor at 60% utilisation, a system such as Airtelligence Provis 2.0 will select two 30kW compressors at 100% utilisation.
These systems can operate up to 16 separate air compressors in a pressure window of only 0.2bar and can also be set to vary the pressure according to production requirements, by lowering pressure at weekends or for varying shifts, for example.
Combined with energy saving options such as heat recovery and leak detection, intelligent controllers have an important role to play in improving efficiency and reducing cost. Let’s not forget, they also optimise performance – and, at the end of the day, that has the biggest impact on productivity.
Learn more about reducing the energy use of compressed air systems with BOGE’s free guides.