The Theory and Application of True Weighted Efficiency -- A New Metric to Evaluate Pump Energy Efficiency Considering Multiple Operating Conditions

Abstract

Energy efficiency is being emphasized more prominently in the pump industry. A consistent method for evaluating pump energy efficiency with multiple operating conditions is needed. New energy efficiency indices have been introduced through legislation in the EU and the US, and some engineers have promoted time weighted efficiency metrics. These methods are helpful, but lack the simplicity, accuracy, or applicability needed when making multi-condition pump system efficiency comparisons. This need is the inspiration behind a new efficiency metric called True Weighted Efficiency (TWE), which is derived from basic engineering principles, using generalized load profiles for one or more system curves, multiple discrete condition points, and varying time of operation at each point. Three numerical Case Studies and three different examples of TWE weighting factors are presented. The ease in which TWE is applied is an opportunity for broad use and adoption in the industry.