Convegni ATI - Accesso riservato soci CTI

Autore: L. Santini, M. Ricotti

Collana: CA - 63 - Palermo 2008

Note:
In this work several layout of closed Brayton cycles employing carbon dioxide as a working fluid are considered and compared in terms of efficiency. Both first and second law approaches have been applied in cycles analysis in order to focus on irreversibility distribution.
Maximum temperatures of nearly 550 °C, compatible with “Generation IV fast reactors projects”, allow to obtain thermodynamic efficiencies competing with conventional Rankine cycles. Further advantages of closed carbon dioxide power cycles are related to the particular layout simplicity and compactness of the turbo machinery due to low specific enthalpy drop and reduced volumetric flowrates caused by the typically high level of pressure of turbine exhaust stream.
Particular care must be put to cycle regenerators effectiveness optimisation, being the regenerated power a considerable portion of the total introduced power. Printed circuit type regenerators due to their compactness, heat transfer efficiency and capability to work at high pressures, seem to be the best suited option for closed carbon dioxide power cycles.