The Turbine Performance of Centrifugal Pumps: A Comparison of Prediction Methods

Abstract

Standard centrifugal Dumps may be operated in reverse as water turbines, and for hydroelectric plums of less than 100 kW (micro- hydro) they are often cheaper than specifically designed turbines. However, in order to use a pump in a micro-hydro scheme, the turbine performance-must be found either by testing or by calculation. Several methods have been suggested for predicting the turbine performance based on the data for pump performance at best efficiency, but they produce a wide range of results. In this paper, eight such methods are compared using an analysis of the effects of poor turbine prediction on the operation of a pump as turbine at a typical micro hydro site. The comparison uses the results of turbine tests on 35 pumps of various types and sizes, some of which have come from the author's own tests. None of the eight methods gives an accurate prediction for all of the pumps but one of the methods can be recommended as a first estimate of the turbine performance.