A pump station is designed where one pump operates while the other pump is in stand-by;...

A pump station is designed where one pump operates while the other pump is in stand-by; the operating curve is shown in Figure 4-12. The pump was sized for the peak-hour flow of 2600 gpm at 200 ft of head. The average daily flow is 2.46 MG. The cost of energy is $0.10/kWh. The variable speed drives have an efficiency of 97 percent, the motor is 90 percent efficient, and, considering the power factor, the conversion from hp to kW is 0.8. What is the average pump speed; what is the energy savings if pumps are converted from constant speed to variable speed?