Deriaz pump-turbine for pumped hydro energy storage and micro applications

The growing importance of the efficiency and operational range of pumped hydro energy storage (PHES) installations, especially for variable load operations, calls for the use of more efficient turbomachinery designs. Deriaz turbomachines are promising candidates, since, among other advantages, they can operate as reversible pump-turbines with high hydraulic efficiency over a wide range of operational loads. Deriaz pump-turbines are largely absent from the literature and this paper gives an overview of their design, application and performance features. Particular attention is given to the hydraulic characteristics and design of a downsized model (6-21 kW) suitable for micro-scale PHES applications. This paper provides a practical and easily-built method to implement a micro Deriaz pump-turbine runner which gives a good outline for design at high yield (about 90%). The analysis is supported by extensive numerical simulations for different working conditions and validated by experimental data. The results confirm the superior characteristics of Deriaz pump-turbines and validate the design process, which is described here for the first time.SCOPUS: ar.j