4E Analyses of a Hybrid Waste-Driven CHP–ORC Plant with Flue Gas Condensation

Abstract

The combination of a waste-driven hybrid heat and power plant with a small organic Rankine cycle unit was recently proposed and investigated from a thermodynamic perspective. The present study provides a more comprehensive assessment from system operation through considering the energy, exergy, exergoeconomic, and exergoenvironmental (4E) aspects in a revised design of this concept to obtain a bigger picture of the system’s technical, economic, and environmental effects on existing and future energy systems. The revised design includes a flue gas condensation unit and alternative friendly organic working fluids. For this, the hybrid plant is modeled for its thermal, economic, and environmental performances. Then, the exergy losses and environmental effects of the system are scrutinized, the cost of losses and pollutions are predicted, and lastly, sorts of solutions are introduced to improve the exergoeconomic and exergoenvironmental performances of the system. The results indicate that the highest share of exergy destruction relates to the incineration (equipped with a steam generator) with a levelized cost of approximately USD 71/h for a power plant with almost 3.3 megawatt electricity output capacity. The hybridization proposal with the flue gas condensation unit increases the sustainability index of the system from 1.264 to 1.28.