Go with the flow
Is your compressed air system sized correctly?
Specifying your compressed air system by flow and pressure – not kW power – is the most accurate way to match its performance to the desired application.
Often compressed air users look at the kW or horsepower rating of a compressor’s motor, especially if they are replacing an existing machine. This number does not provide enough information to specify precisely a new compressor because there are often several options for flow and pressure within the same kW category. For example, in the 11 kW range, Atlas Copco offers four compressor models with a 30% differential in flow rate (from 28.7 l/s to 35.8 l/s at 7 bar.g). This results in over 32% difference in the unit’s purchase price!
Modern air compressors can offer reduced specific energy requirements, better productivity, and lower lifecycle costs. This is possible only when the compressed air equipment is correctly matched in terms of pressure and flow to process demands.
Many real life examples show that the enhanced performance of a new compressor often allows it to replace a higher kW rated machine, leading to a smaller purchase price and reduced running costs in comparison to the higher rated model. Such was the case of the compressed air installation at Crossgrove. Read the Crossgrove application story here.
There are a few essential rules that will help you get the most from your compressed air investment
1.Start with a compressed air audit
Assess present and future needs by first checking out the existing system, from air output to point of use, with a thorough air audit.
2. Match the air demand
Do not rely entirely on the stated motor power rating to match the compressor performance to the process air demand.
3. Pressure + flow = energy = cost
Start with the pressure and flow requirement and then find the best fit in terms of drive motor power. Always keep in mind: pressure + flow = energy = cost
The compressed air equipment in an installation determines the requisite working pressure of the system. This does not depend on the compressor only, but also on the design of the compressed air system and all of its pipework, valves, dryers, receivers, and filters. Simultaneously, the nominal air requirement for an application should be determined by calculating the air consumption for all the tools, machines and processes that will be connected. It should also include an estimate of their individual utilisation factors. Consider also potential leakage, wear, and future changes in the compressed air requirement which, experience shows, should be based on a probability factor that is close to 60 per cent.
When it comes to replacing existing equipment, most small businesses and workshops would agree that to get the best return on their capital investment it pays to carry out due diligence. One way to stay on the safe side and ensure efficiency improvements with the new equipment is conducting an #aircheck – Atlas Copco free visual inspection of the compressed air installation.. This should be done both prior to replacement and at regular intervals after any new equipment has been installed.
Contemporary air compressors, when correctly matched in terms of pressure and flow, can reduce specific energy requirements (SER), improve productivity, and lower lifecycle costs. It pays off to invest in modern compressed air equipment that is selected based on an expert analysis of the application.