Investigation of the performance of combined Brayton-organic rankine cycle system

In this study, thermodynamic analysis of organic Rankine cycle (ORC) using waste heat from intercooler and regenerator in Brayton cycle as heat source is presented. The effects of different compressor pressure ratio in Brayton cycle is investigated on overall system. The amount of energy recovered by the ORC has been calculated. The effects of using organic Rankine cycle as intercooler on whole system efficiency are investigated. Pressure ratios, at which using ORC as intercooler in Brayton cycle is significant, are presented. Performance variation of combined system at different conditions are performed. The first and second law analysis to the ORC and Brayton cycle were applied. Net produced power by the combined the organic Rankine cycle and Brayton cycle with increasing pressure ratio is increased from 397.6 MW to 430.5 MW. While 2.8% and 4.5% of the net power is produced by the ORC used as an intercooler, 5.2% and 6.3% of the net power is produced by the ORC in the regenerator outlet. Moreover, the performance of the system is evaluated for Benzene, p-Xylene and Toluen working fluids.