Economic feasibility analysis of variable-speed pumps by simulating 15 multiple water distribution systems

Abstract

The UN Sustainability Goals address measures to reduce environmental pollution. Water distribution systems (WDSs) use electric energy, which pollutes the atmosphere through, at least partly, the burning of coal. This study simulates, through modeling, variable-speed pumps (VSPs) on 15 different real WDSs on the network solver EPANET and analyzes the payback period. An algorithm is introduced here to select the optimal pump speed pattern to save the most energy while satisfying the constrain of sufficient pressure at all times and all locations. It was found that five of the 15 systems operated unsuccessfully using a VSP, due to the VSP operating at lower speeds causing a lower pressure than normal, thereby causing the pressure to become negative. Additionally, a new chart that compares the payback period, project life, and energy costs between the base case and the VSP case was developed and different regions on the chart reflect different decision criteria. HIGHLIGHTS VSPs can save energy in a water system.; However, VSPs does not always save energy.; Thus, do not install VSPs if there is not enough pressure everywhere in the system.; Installing a VSP may or may not pay for itself over the lifetime of the pump.; Saving energy may be worth considering it for reducing climate change, effects even though the costs are not recovered.;

Keywords

• economics
• energy
• engineering
• public health
• water supply