Many factories keep a fixed-speed screw compressor running 24/7 even when air demand is low. During unload, a fixed-speed unit can still consume around 70% of full-load power, which makes electricity one of the largest hidden operating costs in a compressed air system.

Why Fixed-Speed Units Waste Energy During Unload

A fixed-speed airend runs at constant speed and unloads by venting air when the pressure setpoint is reached. The motor continues to spin, so power consumption stays high even when no useful compressed air is produced.

How PM VSD Compressors Match Air Demand

A variable speed screw air compressor continuously adjusts motor speed according to the system pressure signal. When production slows down, the compressor slows down instead of wasting energy during unload.

Realistic ROI for a 22 kW System

For a 22 kW machine running 6,000 hours per year, a 25–35% energy saving can reduce annual electricity cost by several thousand dollars depending on local tariffs. In many cases, the VSD premium is recovered within 18–24 months.

Review the rotary screw air compressor manufacturer series or contact Panrui for an energy-saving calculation.