A typical compressor application uses a constant speed motor to run the compressor. The compressor uses the energy it needs from the motor and the rest is wasted. For example, an inlet modulated air compressor will use 80% of its full load power while at 50% of rated capacity.
An air compressor VFD or variable speed drive (VSD) adjusts the compressor speed to match the air demand on the system. This reduces energy use by ensuring that the motor only generates enough energy to power the compressor. Studies have shown that a 20% reduction in motor speed can lead to 50% energy savings.
An incentive of $150 per hp (up to 100 HP) for the installation of a VSD/VFD on compressed air systems for retrofits and new construction projects. Larger VFDs may qualify for a custom incentive.
The payback period for an air compressor VSD/VFD will vary based on the loading on the system. Paybacks of less than two years are common.