Energy and exergy analyses of a new atmospheric regenerative Brayton and Inverse Brayton cycle

Abstract

A regenerative Brayton & Inverse Brayton cycle has been already proposed to improve the thermal efficiency of the standard Brayton cycle as a Brayton &Inverse Brayton cycle did. All processes in the bottoming cycle take place at sub-atmospheric pressure. A new arrangement of the processes has been introduced in the present study to decrease the flow rate through the bottoming cycle. The new arrangement of the processes also performs an atmospheric exhaust airflow through the regenerator. Thermal performance of the new cycle is compared with that in the original regenerative Brayton & Inverse Brayton cycle. Performances of the two cycles are compared at different pressure-ratios of the compressors. Calculated results show that the thermal efficiency, the specific net output power, the specific heat supplied to the combustion chamber, and the total rate of exergy destruction are no longer strongly dependent on the pressure-ratio of the second compressor and are weakly dependent on the pressure-ratio of the first compressor in the new cycle. Meanwhile, the specific net output power of the new cycle is considerably greater than that in the original one (30%–250%). The new cycle is recommended to use at moderate pressure-ratios of the first and second compressors.