Exergy, economic and environmental impact assessment and optimization of a novel cogeneration system including a gas turbine, a supercritical CO2 and an organic Rankine cycle (GT-HRSG/SCO2)

Exergoeconomic and exergoenvironmental analyses are reported for a novel cogeneration system including a gas turbine, a heat recovery steam generator, a supercritical carbon dioxide recompression Brayton cycle and an organic Rankine cycle. A comprehensive parametric study is carried out to clarify the effects of some decision parameters on the exergoeconomic performance of the proposed system. Also, the payback period is determined for the proposed system. The sum of capital investment cost, total exergy destruction cost and environmental impact cost is considered as an objective function which is optimized with respect to the decision parameters. The variation in overall exergoeconomic factor is determined and its implication to the system design is discussed. It is observed that under the optimized condition the average product unit cost of the system (cost of produced power and steam) is decreased by 0.56 $/GJ when compared to the value obtained under a base condition.