Thermo-economic optimization of biomass-fired organic Rankine cycles combined heat and power system coupled CO2 capture with a rated power of 30 kW

Combining organic Rankine cycle (ORC) and biomass direct combustion to form a combined heating and power system (CHP) is a feasible technology to realize small biomass power generation. A small-scale biomass-fired ORC-CHP system with a rated power of 30 kW is proposed and the thermo-economic optimization under two operation strategies is discussed. The effects of key operating parameters on exergy efficiency and levelized energy cost (LEC) are analyzed. Meanwhile, a single-objective optimization for maximum exergy efficiency or minimum LEC is addressed, and a further thermo-economic optimization is examined. The Pareto-optimal solutions using three decision makings are yielded and compared. Research demonstrates that the exergy efficiency of model A increases with condensation temperature, while the exergy efficiency of model B first increases, reaches the peak, and then slightly decreases. The split ratio has a significant effect on model B. The Pareto-optimal solutions from TOPSIS decision making are selected because of its lowest deviation index. The Pareto optimal solution for models A and B in pairs of (exergy efficiency, LEC) are (19.69%, 0.2968) and (19.75%, 0.2975), respectively. Compared to model A, model B presents higher thermodynamic performance and slightly lower economic performance.(c) 2022 Elsevier Ltd. All rights reserved.