Question

Water is pumped from a lake to a large storage tank that is 15 m above at a rate of 70 L/s while consuming 15.4 kW of electric power. Disregarding any frictional losses in the pipes.

a. Starting from the conservation of energyequation in the units of Watts, simplify the equation for the case where you want to determinethe mechanical energy added to the water by the pump. Explain why you can eliminate each termyou would not need. The final form of the equation should be in terms of parameters given in a typical problem.
b. Calculate the overall efficiency of the pump-motor unit.

Answer 1

Water is pumped from a lake to a storage tank of 15 m above at a rate of 70 L/s while consuming 15.4 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine (a) the overall efficiency of the pump-motor unit and (b) the pressure difference between the inlet and the exit of the pump.Explanation: