Thermo-economic analysis and multi-objective optimization of a novel waste heat recovery system with a transcritical CO2 cycle for offshore gas turbine application

In this paper, a novel power cycle for the cascade utilization of waste heat from an offshore gas turbine is presented. Carbon dioxide is selected as the single working fluid to further simplify the power conversion system. Mathematical models for the heat recovery system are developed to investigate the improvement in thermodynamic and economic performance. Moreover, a comprehensive parametric analysis is carried out and discussed to evaluate the effects of key cycle parameters on system performance. Further, a multi-objective optimization of the system based on Artificial Bee Colony algorithm is conducted to obtain the optimal operating parameters, considering net power output and levelized energy cost as objective functions simultaneously. The results show that the presented waste heat recovery system operating at the design point can increase the net power output by 30.1% compared with the gas turbine alone. The presented cycle demonstrates superior performance than the typical cycle layout with the improvement in net power output by 5.3% and the decrease in levelized energy cost by 1.2% at optimal condition. The findings so far revealed that the proposed CO2 power cycle has potential for waste heat recovery in the offshore platform application.