CCWI2017: F2 'An Energy Evaluation of Common Hydraulic Thresholds in Water Mains'

This study uses a regression-based modelling approach using an ensemble of 20,000 water mains compiled for 17 North American networks to understand the relationships between pipe factors (pipe flow rate, unit headloss, proximity to major components, average pressure, and diameter) and energy efficiency/energy loss performance metrics. The regression analysis aims to predict efficiency values in pipes based upon common-practice values of average pressure and unit headloss to better understand the energy performance associated with those thresholds. The results of regression analysis show that commonly considered pressure ranges (30-50 m) correspond to good values of the energy needed by user (ENU) metric, with pressure deficient pipes by definition having lower, non-ideal ENU values. For unit headoss, common thresholds that would trigger pipe replacement (3 m/km in transmission mains, 10 m/km in distribution mains) correspond to net energy efficiency (NEE) of 74.9 and 74.6 percent, respectively, for the ensemble of water mains analyzed. These pipes represent the poorest performers and while there are not many such pipes within the ensemble, as NEE of 74.6 corresponds to the 7 th percentile, there is a need for tools and analyses like these to help water utilities identify the pipes with the greatest energy impact from across their water distribution systems.