Cost efficient and practical design of water supply network using harmony search

Water supply network is a key infrastructure in urban civilization and agricultural irrigation. In order to save the design cost of a network, which contains a nonlinear relationship between hydraulic energy loss and water flowrate, researchers have traditionally used mathematical optimization approaches. However, they have been more interested in meta-heuristic approaches recently because (1) these approaches directly provide commercial discrete diameters instead of impractical continuous ones; (2) they do not require complex gradient derivatives and free from divergence; (3) they do not require starting feasible vector and have more chance to find global optimum, etc. This study presents a new real-world example for the water network design, hoping to be a good literature. Furthermore, this study newly considers a more practical constraint (flow velocity range) that can avoid a critical problem of water hammer or pipe choking by sedimentation. Then, the numerical example is solved using a metaheuristic algorithm named harmony search, and the results are compared with those from a mathematical approach.