Considering the benefits of retrofitting centrifugal fan rotors

An understanding of how different flow control methods (inlet dampers vs. VFDs) affect a fan's efficiency and plant operating costs will be discussed. Case studies are considered to provide an understanding of the required data and eligibility for pursuing fan efficiency retrofits. Opportunities for retrofit are generally practical when there are oversized fans, process changes, or when there is equipment addition to the system. Benefits of energy efficiency retrofits can be predicted from field studies and an ROI is determined. Whether or not fan casing, ductwork, and existing motors and motor components can be reused is considered in the cost analysis. Also, there are generally rebates and incentives from local utilities can contribute to funding to assist with providing the necessary return on investment. In this paper, predicted ROI is compared to actual field results.