Abstract: The analytical formulas for the relations between power density and pressure ratio of a real regenerated Brayton cycle coupled to variable-temperature heat reservoirs are derived by using finite-time thermodynamics. In the analysis, the irreversibilities involve the heat resistance losses in the hot-and cold-side heat exchangers and regenerator, the irreversible compression and expansion losses in the compressor and turbine, and the pressure losses in the piping. The effects of the thermal conductance distribution of hot-and cold-side heat exchangers and of the thermal capacity rate matching between the working fluid and the heat reservoirs on the power density are studied by detail numerical examples.

Key words: regenerated, finite-time thermodynamics, Brayton cycle, power density