Predição de operação de bombas como turbina e sua aplicação para recuperação de energia em sistemas de distribuição de água

Abstract

Pumps as turbines (PAT) are a sustainable alternative for generating energy by taking advantage of the hydraulic potential of a site. However, there are difficulties in predicting the turbine mode characteristic curves for off-design operating points, based on the curves provided by the pump manufacturers. The purpose of this work is to predict the PAT operating range of pumps selected to work as pressure-reducing valves (PRV) in the water supply system (WSS) of Vila Permanente, in Tucuruí - Pará, Brazil. Three experimental studies were evaluated for the prediction of head (Ht) and flow (Qt) of PATs in turbine mode at the best efficiency point (BEP). Then, a second method was applied that considers the entire operating range of PAT, combined with the methods in the BEP to obtain characteristic curves QxH (flow x head) and Qxη (flow x efficiency) of PAT. With the head and flow values of the pressure points in the WSS under study, centrifugal pumps were selected to work as turbines, applying the best combination of method and obtaining the characteristic curves of PAT in turbine mode, in order to obtain the operation range of the PAT, in addition to the calculations of partial energy recovery with values of 372.3 MWh/ year.