Ecological performance analysis of an endoreversible modified Brayton cycle

Abstract

An endoreversible closed modified simple Brayton cycle model with isothermal heat addition coupled to variable-temperature heat reservoirs is established using finite-time thermodynamics. Analytical expressions of dimensionless power output, thermal efficiency, dimensionless entropy generation rate and dimensionless ecological function are derived. Influences of cycle thermodynamic parameters on ecological performance and optimal compressor pressure ratio, optimal power output, optimal cycle thermal efficiency and optimal entropy generation rate corresponding to maximum ecological function are obtained and compared with those corresponding to maximum power output. The results show that cycle thermal efficiency improvement and entropy generation rate reduction are obtained at the expense of higher compressor pressure ratio and a little sacrifice of power output at maximum ecological function. The compromises between power output and entropy generation rate and between power output and cycle thermal efficiency, respectively, are achieved.

Keywords:

• finite-time thermodynamics
• modified Brayton cycle
• ecological performance
• performance comparison

Acknowledgements

This paper is supported by the National Natural Science Foundation of People's Republic of China (Project No. 10905093). The authors wish to thank the reviewer and the editor for their careful, unbiased and constructive suggestions, which led to this revised manuscript.