Session: Student Poster Competition

Submission Number: 185974

Cost-Efficiency Trade-Off in Allam Cycle Recuperator Performance: A Practical Assessment of Effectiveness. 

In Allam-like sCO2 cycles, the recuperator is essential for achieving high thermal efficiency but also represents a dominant capital expenditure (CAPEX) driver. Previous assessments by the authors indicate that this component alone can account for approximately 54% of the total equipment CAPEX under baseline operating conditions. As a result, the choice of target recuperator effectiveness constitutes a critical design decisions with direct implications for both performance and economic feasibility.

This work investigates the performance-cost trade-off associated with recuperator effectiveness by analysing an Allam-cycle power block under fixed boundary conditions. Recuperator effectiveness is systematically varied over a wide range (70%-100%), and, for each case, thermal efficiency, total specific CAPEX, incremental CAPEX penalty per percentage point, and the evolution of the power block CAPEX breakdown are evaluated. This approach enables the identification of regions where additional efficiency gains are obtained at disproportionately high cost.

Two independent decision criteria are applied to identify a practical compromise effectiveness: (i) an efficiency saturation criterion, defined as the effectiveness at which 80% of the total achievable efficiency gain is captured, and (ii) an incremental CAPEX penalty analysis, used to detect sharp increases in marginal cost. Both criteria consistently identify an effectiveness of approximately 95%.

At this point, most of the attainable efficiency improvement is already realised, while further increases in effectiveness lead to a rapid escalation in recuperator size and cost. The study provides a design-oriented guideline for preliminary sizing and techno-economic screening of recuperator-intensive sCO2 power cycles.

Presenting Author: Giovanny Lopez Muñoz University of Seville

Presenting Author Biography: Giovanny López is a PhD researcher at the University of Seville and a Marie Skłodowska-Curie fellow within the ISOP project. His research focuses on power cycles based on directly fired oxy-combustion supercritical CO2 systems, with emphasis on thermodynamic benchmarking, exergy analysis, and the integration of air separation units for flexible, low-carbon power generation. He has experience developing detailed simulation models and has collaborated with industry partners on techno-economic assessment of emerging energy systems.

Authors:

Giovanny Lopez Muñoz University of Seville
Francesco Crespi University of Seville
David Sánchez University of Seville