Influence of Topography, Peak Demand, and Topology on Energy Use Patterns in four Small to Medium-Sized Systems in Ontario, Canada

Abstract

The aim of this paper is to characterize the relationship between system characteristics of topography, peak demand, and topology and the energy dynamics of four small to medium-sized water distribution systems in Ontario, Canada. First, previously developed energy indicators were used to evaluate and compare the energy efficiency, energy lost to friction, energy lost to leakage, and the surplus energy of the four systems. The systems had a high energy efficiency ranging from 75 to 94% (leak-free) and 58–70% (leaky). Friction losses comprised 3–22% of the total energy input to the systems. Energy lost to leakage comprised 23–26% of total energy input to the systems. Second, hypothesis testing was used to identify statistically significant correlations between system characteristics and energy use patterns in the system. No statistically significant correlation was found between the standard deviation of node elevation and energy use in the four systems. Hydraulic redundancy and energy use did not have a statistically significant correlation. This is because during a ‘typical’ day of service, the most efficient flow paths are concentrated through the trunk mains rather than in the smaller distribution mains that account for most of the looping and hydraulic redundancy of a system. Correlations between peak hour factor and the energy indicators were near the cut-off p-value level (p < 0.05) so it was not clear if the correlations are statistically significant. Despite this, moderate to high Spearman rank correlation coefficients (−0.6 to +0.8) were calculated for the leaky and leak-free systems.