Optimization Analysis of Water Supply Distribution System The Case Study of Awash Sebat Killo Town Distribution System
No Thumbnail Available
Date
2018-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Water supply distribution systems estimated to account of 80 to 85% of the total cost for
the whole Water supply project (International Journal of Mechanical Engineering and
Technology, 2014), that include source development, pump and motor house (including
Pump and Generator) construction of treatment plant and reservoirs. Unless the cost for
distribution system made to be decreased or optimized, the increase to the total project
cost of the water supply system is inevitable. Thus, the problem is how to implement the
water supply distribution network with optimum cost.
Currently, pipe sizes in distribution networks are assigned by trial and error method.
Then pressure and velocity values are checked whether they are within permissible
values or not.
This study is prepared to show how the formulated methodology using Matlab bring
about optimized pipe size and hence reduction in the pipe network cost. The distribution
system taken as a case study for analysis is Awash Sebat killo town water supply
distribution system.
Eight loops are selected from the total distribution network based on the size of pipes
found in the loops. The pipes in the selected loops have larger pipe sizes than other
loops. Therefore, it is found reasonable to optimize these loops to get considerable cost
reduction.
The optimization process was carried out taking the pressure values, pipe lengths, Nodal
demands from the output of Epanet. The main constraint, pressure output, is made to
pass through calibration test before it is being used for optimization by Matlab.Objective and constraint functions are written in Matlab-file. The Objective function is
the sum of the product of cost of each type of pipe per unit meter length. The Constraints
are: the sums of the head loss around a loop need to be equal to zero, and the pressures at
nodes in the loop must be greater than 15m, and flow velocity in the pipes need to be
greater than 0.6m/sec.
After optimization process was completed changes for pipe sizes in the selected loops
are noted. And these new optimized pipe diameters are entered in the design software
(Epanet) to check whether the design criteria were preserved or not. The result shows
that the pressure values at the nodes of the considered loops are greater than 15m. The
analysis shows that the new optimized pipe diameters satisfy the required demand at the
nodes before optimization is carried out.
The total cost of the pipes before optimization is compared with that after optimization.
As a result, the total cost reduction is found to be 15.87% of the total cost for the pipes
and fittings in the whole network.
Finally, recommendation is suggested to use the methodology developed to attain
economical pipe sizes by reviewing any designed water supply distribution system.
Description
Keywords
Water Supply, Awash Sebat Killo, Distribution System, Optimization