Donsco’s Green Commitment: Upgrades Wrightsville Foundry Compressed Air System

Donsco is always seeking ways to be green; one way is reducing our energy usage. Donsco recently replaced a 300 horsepower fixed speed, single stage compressor with a 55-300 horsepower variable speed drive (VSD) compressor. An intelligent flow control valve was also installed to buffer fluctuations between the air supply and plant air demand. Through the installation of an intelligent flow control valve, compressed air storage tanks are refilled in the most energy efficient manner and then the air is regulated to the plant depending on the actual demand which may vary several times a minute. Also, the new VSD compressor takes the primary role of lead compressor during periods of low demand such as between production shifts and weekend maintenance work. This enables the compressor to reduce its output down to 55 horsepower compared to the previous state in which a 150 horsepower compressor had to run to supply a very low volume of compressed air. Finally, a system controller was installed to efficiently manage the four compressors system by using a base load and trim strategy to ensure the lowest amount of energy is used to supply the plant’s requirements.

The benefits of the project were immediate.

  • Lowered the plant air pressure set point from 100 to 84 psi yielding an 8% energy savings
  • Decommissioned an existing 300 horsepower single speed compressor
  • Yielded a 30% energy savings versus the decommissioned single speed compressor due to ability to vary the energy with the VSD compressor
  • Dramatically improved plant pressure stability due to intelligent flow control valve

Stay tuned for more Donsco Green Initiatives.