This case study describes an optimization project implemented on a fan system at Ash Grove Cement Company, which led to annual energy and maintenance savings of $16,000 and 175,000 kilowatt-hours (kWh). In 1999, Ash Grove Cement Company implemented an optimization project on a fan system in its cement plant in Durkee, Oregon. Because of a severe vibration problem, the fan system would often fail and require frequent repairs to the ductwork and adjoining machinery. The plant replaced the belt drive with an Adjustable Speed Drive (ASD) to improve the control of the fan system and lower its energy consumption. This change eliminated the vibration problem and improved the system's airflow control and energy efficiency. The project led to annual energy and maintenance savings of $16,000 and 175,000 kilowatt-hours (kWh). In addition, the fan system's improved reliability allowed the plant to achieve its desired production level. Because of partial funding from the Northwest Energy Efficiency Alliance (NEEA), the total project cost was approximately $10,000, which gave the Durkee plant a simple payback of 7.5 months.
