Assessment of thermodynamic performance of a 20 kW high‐temperature electrolysis system using advanced exergy analysis

Abstract

AbstractThe thermal efficiency of the high‐temperature solid oxide electrolysis cell system for steam electrolysis has drawn extensive concern in the energy conversion field. This work presents a thermodynamic investigation of a high‐temperature steam electrolysis system by conventional and advanced exergy analyses. A steady‐state simulation of a 20 kW high‐temperature steam electrolysis system is performed for system performance analysis. The thermal inefficiency of each component in the system is revealed by conventional exergy analysis. The predictions show the system exergy efficiency is 49.98%, H2‐compressor has the largest exergy destruction (6773.6 W, 39.16% of the total exergy destruction). Through advanced exergy analysis, the impacts of the interactions among components and the technical limitation with each component are considered. The results indicate the H2‐compressor has the highest exergy saving potential owing to the largest avoidable exergy destruction (1935 W), followed by the stack and vapor generator. Thus, the solid oxide electrolysis cell stack, H2‐compressor, and vapor generator have tremendous potential in energy conservation. Advanced exergy analysis also indicates the interactions among components have less influence on the exergy destruction which means most measures toward improving high‐temperature steam electrolysis systems should be taken to improving each component itself rather than interconnections among components.