Modelling a low-head seawater-pumped hydro storage system's impeller for energy production within a small island developing state

Abstract

ABSTRACT The proposed seawater pumped hydro storage (SPHS) is one option for providing a buffered energy storage system that will surely be required in the future. Given the fact that most small island developing states (SIDS) are isolated and surrounded by large bodies of water, the medium of seawater becomes an infinite supply. However, SIDS are also low lying and therefore only low heads will be available at high flows to maximize the energy efficiency of the system. The computational fluid dynamics (CFD) model, ANSYS Fluent, was used to simulate this SPHS pump turbine impeller at low heads and high flows. This pump turbine impeller was simulated to function as both a pump and as a turbine at various revolutions per minute (rpm). The performance of the system was evaluated based on the pressure and velocity distributions of the pump turbine impeller at varying rpm. It was found that there were less energy losses within the turbine mode compared to the pump mode. Furthermore, this study showcases that the CFD model ANSYS Fluent is an economical, efficient, and easily diagnosable technique for analysing an impeller in both pump and turbine modes.