Choosing the correct screw compressor capacity starts with total air demand, not with a guess based on the number of machines. An oversized unit wastes energy, while an undersized unit drops pressure and causes production losses.
Start with Air Demand
Add the free air delivery required by every air consumer, then apply a usage factor for tools that do not run continuously. Convert the total to m³/min or CFM at the required working pressure.
Duty Cycle and Safety Margin
- Choose capacity at least 20–30% above average demand.
- Allow for leaks, future expansion, and peak-start events.
- Confirm the working pressure before comparing kW ratings.
Common Sizing Mistakes
- Buying by motor kW instead of free air delivery.
- Ignoring the pressure drop across piping and dryers.
- Using one compressor at 100% load with no back-up capacity.
For a full air audit, contact Panrui or review the rotary screw air compressor series.
