Energy and exergy analysis of an organic Rankine-Brayton combined cycle

Abstract

In this study, thermodynamic analysis of reheat and intercooled Brayton cycle combined with organic Rankine cycle (ORC) using waste heat from intercooler in Brayton cycle as heat source is presented. The effects of different compressor pressure ratio and using organic Rankine cycle as intercooler in Brayton cycle on whole system efficiency are investigated. Pressure ratios at which using ORC as intercooler in Brayton cycle are presented. While power generation in ORC between 606 kW-11795 kW according to pressure ratio has been provided with adding organic Rankine cycle to the Brayton cycle, the efficiency of combined cycle in comparison with Brayton cycle has been increased among 0.2% to 2.5%. Thermal efficiency of cycle (ORC) is varied between 1%-12%. Likewise, second law efficiency of organic Rankine cycle according to pressure ratio is varied between 10%-55%. In the organic Rankine cycle, the greatest exergy destruction is occurred in the evaporator.