Optimal Design of Pumping Mains Considering Pump Characteristics

Abstract

The total cost of a pumped water supply system includes the capital costs of the pipeline and pumping units, the replacement costs of various components included, and the energy costs related to the system’s operation. The capital cost of pipeline and energy cost are nonlinear functions of the pipe diameter. In addition, the pump characteristics, the replacement costs of components, and the escalating energy costs are of a nonlinear nature. In this paper, a nonlinear optimization model is developed to design a pumping main for required discharge, static head, pump characteristics, and economic parameters. The optimization model minimizes the total annual cost of the pumping main and pump, satisfying the pump characteristic curve equations. The applicability of the developed model is demonstrated with the help of a design example. The optimization model determines the optimal diameter of pumping main with pump efficiency for a required discharge or optimal discharge range with pump efficiency for an available diameter. The optimization model shows the effect of escalating costs of components and energy on the size of pumping main. Further, the model can also be used to determine the optimal operating conditions for a new pumping system or to evaluate an existing pumping system.