Session: Student Poster Competition

Submission Number: 187134

Expected Designs for Hp Steam and Supercritical Co2 Turbines Across Different Applications 

The recent interest in supercritical carbon dioxide (sCO2) power cycles—particularly due to their potential to provide electricity in a clean, efficient, and compact manner— has brought about a focused examination of axial turbine design. When analysing an emerging technology, it is valuable to compare it against a familiar reference, especially one it might replace in selected applications. High-pressure steam turbines are selected as a benchmark for future sCO2 turbine designs because their geometry class and overall pressure-ratio envelope are closest to axial sCO2 machines. This choice allows to retain stage architectures and similar expansion ratios to isolate the influence of the working fluid only.

This paper provides application-conditioned insights through a mean-line analysis of what an axial sCO2 turbine would look like to deliver a target power output, and compares that outcome against a like-for-like steam HP design. The comparison is deliberately focused on applications and temperature levels where sCO2 technology is emerging as a substitute for steam Rankine cycles: nuclear, concentrated solar power (CSP), and waste-heat recovery (WHR). Representative cases are constructed in which an sCO2 cycle could plausibly be selected in lieu of a steam Rankine cycle, aligning heat-source temperature windows and application objectives such as efficiency, power, and geometric constraints. The maximum temperature is set to 550 °C to enable martensitic steels, ensuring that observed differences in size, stage count, manufacturability, and operability primarily trace to working-fluid physics and application-driven requirements. Low-pressure condensing effects and out-of-scope temperature regimes are intentionally excluded to avoid skewing the comparison. This framing anchors the results in the decision facing developers who are weighing sCO2 instead of Rankine for a given project.

To the best of the authors’ knowledge, a systematic, application-conditioned, like-for-like mean-line comparison of axial sCO2 and steam HP turbines —under a fixed materials window to isolate fluid effects and illuminate manufacturability and stage-count implications— has not been reported. The design maps and envelopes presented here provide actionable starting points for teams considering sCO2 in place of steam for a given application, and they frame clear next steps for 3D refinement and techno-economic assessment.

Presenting Author: Adonis Constantinidis University of Seville

Presenting Author Biography: Adonis Constantinidis is a PhD candidate in Energy Engineering at the University of Seville and a Marie Skłodowska-Curie fellow within the iSOP project. His research focuses on supercritical carbon-dioxide turbine design and their flexibility enhancement during low load operation, in particular windage effect.

Authors:

Adonis Constantinidis University of Seville
Giovanny Andrés López Muñoz University of Seville
Rafael González Almenara University of Seville
Vasileios Pastrikakis SoftInWay Inc.
David Sanchez University of Seville