Performance analysis of double suction pumps as turbines (DS-PaT) for clean energy generation and storage in hybrid systems: Experimental and numerical insights

The transition to renewable energy demands innovative technologies for efficient energy generation and storage. Double-suction pumps operating as turbines (DS-PaT) are emerging as a pivotal technology in Pumped Hydro Energy Storage systems, known for their high hydraulic efficiency and operational versatility. Despite their promise, the performance characteristics of DS-PaT under varying conditions, particularly their dual functionality in pump and turbine modes, are not fully understood. This study provides a comprehensive evaluation of DS-PaT performance through a combined approach of experimental testing and Computational Fluid Dynamics simulations. Key findings reveal that in turbine mode, DS-PaT achieves a 44 % increase in flow rate and a 39 % increase in head compared to pump mode at the Best Efficiency Point. Although turbine mode efficiency is slightly reduced to 97.5 % of pump mode efficiency, it remains within operationally acceptable limits. The research also delves into cavitation phenomena, demonstrating that while DS-PaT in turbine mode is susceptible to cavitation due to higher operational heads and flows, it shows significant resilience against cavitation-induced damage. This work advances the understanding of DS-PaT operational dynamics and underscores their potential for broader application in renewable energy systems, particularly in enhancing the efficiency and flexibility of Pumped Hydro Energy Storage systems.