Compressed Air Efficiency: A Case Study Combining Variable Speed Control with Electronic Inlet Valve Modulation

This paper discusses an energy efficient compressed air system at an industrial automation components manufacturing facility. The authors performed and energy assessment as part of the DOE's Industrial Assessment Center program and followed up with additional investigations on the compressed air system.

The compressed air system utilizes an outlet pressure transducer to a microcontroller to adjust system capacity by changing motor speed and modulating an electric proportional inlet valve. This control system allows reduced modulation of operating pressure and a lower operating set point, when compared to either system alone, and avoids thermal overloads when the VFD attempts to operate at low frequencies. The control system will be examined and discussed with respect to operation, energy savings, installation costs, and payback.