Economical Aspects

Not every pump application will benefit from VFD control. The only way to determine if a VFD will result in an economically satisfying solution is to do a thorough analysis. Pumping with variable frequency drive (VFD) controlled systems can be separated into two different cases:

- A variable continuous flow is required by the process (common for industrial applications). The normal way to control the flow is by throttling. The use of a VFD will, in most cases, lead to a substantial energy reduction.

- VFD vs. ON-OFF regulation (common for sewage applications). Variable speed drive is used to reduce pipe system losses when pumping. The effect of the VFD-control depends on the pipe system used. Systems with high losses relative to the geodetic head will benefit from VFD control, while the impact of a VFD in lift systems (low losses relative to geodetic head), is negligible at best. A though system analysis has to be performed in order to determine whether variable frequency control might be economically motivated.

This type of analysis can be performed with Xylem Water Solutions pump selection program,
Flyps. Contact your Xylem Water Solutions representative to get support on this.