Finite Time Thermodynamic Modeling of a Indirectly Fired Gas Turbine Cycle

Indirectly or externally-fired gas-turbines (IFGT or EFGT) are novel technology under development for small and medium scale combined power and heat (CHP) supplies in combination with micro gas turbine technologies. In this paper, the theory of finite time thermodynamics is used in the performance analysis of a class of irreversible closed IFGT cycle coupled to variable temperature heat reservoirs. The analytical formulae for dimensionless power output and efficiency, as functions of the total pressure ratio, the component (HTHE, hotand cold-side heat exchangers) effectivenesses, the compressor and turbine efficiencies and the thermal capacity rates of the working fluid and the heat reservoirs, the pressure recovery coefficients, the heat reservoir inlet temperature ratio, are derived. The model derived can be used to optimize operational parameters and forecast performance of real IFGT configurations.