Attributes of Bi-Directional Turbomachinery for Pumped Thermal Energy Storage

Abstract In this paper, we (i) present a methodology for determining the aerodynamic performance of bi-directional turbomachines pumped thermal energy storage, i.e., designed to operate as compressor in one direction, and then turbine opposite (ii) carry out computations such turbomachines, (iii) propose principles conceptual design these devices. Focus is placed on using storage cycle not only identify novel requirements but also estimate effect efficiency process. particular, difference between loading forward backward operation causes blading work at incidences leading below maximum efficiency, resulting lower round-trip efficiency. The description includes determination number stages, definition nondimensional parameters selection, optimization two-dimensional operation. assessment stage count shows relationship relative Mach number, pressure ratio, are assessed through analogue existing “Smith charts,” single-direction function camber stagger. blade shape evaluation show how profile can be modified address turbomachine, enabling an increase two percentage points compared baseline double circular arc configuration.