Pumping Systems and Energy Efficiency in Water Utilities

This document discusses the importance of proper pump selection, variable frequency drives, motor efficiency, and hydraulic modeling in improving energy efficiency in water utilities. It also explores future research possibilities such as in-line turbines.

PLANT & PROCESS
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QUESTION 1
Task 1
Task 2
Task 3

Resistance curves
Task 4

No.: 4
Using the dimensions and the condition provided by the design problems, various parameters are
included as shown in the calculations.

QUESTION 2
Introduction
Pumping is used in the transfer of water from the source which may be a river or a water
treatment plant to the required destination which may be a storage reservoir or treatment plant
for the case a drinking water system. A significant number of the water plumbing systems
possess a combination of static head height between destination and source of the water and a
friction head within the pipes, valves as well as other equipment found within the systems.
Technology currently being used
Pumping: Proper selection of pump is crucial in the efficient operations of a pumping system.
The rates of flow, as well as the pressure within the pumping system, should be established to
ascertain if the pump would be efficient (Giustolisi, Berardi, Laucelli, Savic & Kapelan, 2015).
Installing variable frequency drives offers one of the ways of enhancing the energy of a water
utility. Variable frequency drives should be taken into consideration in cases the pump is
oversize or when a throttling valve is used in the operations of the pump. Variable frequency
drives adjust the speed of rotating of the electric motor through control of the frequency of
supplied electric power to the motor. The use of variable frequency drives has been
approximated to lower energy consumption by 50% as the variable frequency drives match the
speed of the motor to the specific energy demands required hence conserving energy since the
drive operates at reduced speeds when needed.
Motors: The pump motor should be evaluated as an aspect of pump system improvement.
Motors are responsible for controlling the speed of the pump and are directly connected to the
efficiency of the pumping machine. A plan should be developed by the water utilities for

upgrading the current motors using a premium efficiency model since such a motor may offer to
the tune of 10% higher efficiency in comparison with the conventional and standard models.
Distribution system pumping: Head loss and friction loss are the main causes of high costs of
pumping in the water distribution system. Utilities may lower the pipe costs through a selection
of pipe with the smallest diameter which offers the lowest velocity at peak demand. Still,
ensuring the pipe is smooth may aid in lowering the friction loss and hence reducing the amount
of energy needed to move the water. Correction of the sizes of the pipes has been established to
be able to save to the tune of 20% of pumping energy.
Hydraulic modeling: Hydraulic models allow utility to simulate the behavior of the water
pumping system hence may assist in predicting the response of the system to variations in
conditions, Such models are typically adopted in long term planning for instance in the design of
new systems as well as enlargement of the existing systems (Rehman, Al-Hadhrami & Alam,
2015).
Future Research
One of the technologies that may form the basis of future research is in-line turbines. These may
be installed in regions in which water utilities have relatively significant changes in the elevation
over the areas of distribution as some of the utilities may pump water in the regions of
distribution at pressures that are higher than the desired line and then fix pressure reducing
valves at the regions of low elevations. The in-line turbines would work by producing electricity
from the excess pressure that would otherwise be wasted

Summary
80% of the energy that is utilized in water treatment as well as distribution is normally ended up
in pumping water (Rehman, Al-Hadhrami & Alam, 2015). Since a large amount of energy is
used by pumps in the lifting and movement of water and since the cost of energy tends to be the
second highest water utility operating budget cost, proper chose on the pumps, controls as well
as motors is crucial in ascertaining efficient systems besides controlling costs.

References
Giustolisi, O., Berardi, L., Laucelli, D., Savic, D., & Kapelan, Z. (2015). Operational and tactical
management of water and energy resources in pressurized systems: Competition at
WDSA 2014. Journal of Water Resources Planning and Management, 142(5), C4015002
Rehman, S., Al-Hadhrami, L. M., & Alam, M. M. (2015). Pumped hydro energy storage system:
A technological review. Renewable and Sustainable Energy Reviews, 44, 586-598