Significant opportunities exist to reduce pumping system energy consumption through smart hydraulic system design, retrofitting to variable speed performance and operating practices. Significant energy savings can be achieved in a pump system by reducing the pump rotational speed. Variable speed drives (VSD) are one of the primary devices used to control pump rotational speed.
The affinity law (the relation between rotational speed, flow, head and power) gives an idea about the saving potential. A change in the rotational speed will change the power consumption with the cubed value of the rotational speed change.
By reducing the rotational speed to half, the power consumption will be reduced to 1/8 of the original.
Thus, the energy saving potential in lowering the rotational speed when full capacity is not required is always very high and should be considered.
Xylem offer a neat tool that with a few data entries will give you an estimated energy saving and payback on the investment.
Find out your energy savings potential with the Xylem Energy Savings Calculator.
Xylem VSD Payback Tool v2.3.12.zip