Exergy-Based Multi-Objective Optimization of an Organic Rankine Cycle with a Zeotropic Mixture

Area of Science:

• Thermodynamics
• Energy Systems Engineering
• Environmental Science

Background:

• Organic Rankine Cycle (ORC) systems are crucial for waste heat recovery.
• Working fluid selection critically impacts ORC efficiency, cost, and environmental footprint.
• Zeotropic mixtures offer potential advantages over pure fluids in ORC applications.

Purpose of the Study:

• To evaluate the performance of an organic Rankine cycle using zeotropic mixtures as working fluids.
• To analyze the influence of system parameters and mixture composition on ORC performance.
• To optimize ORC performance using multi-objective optimization based on exergy, cost, and environmental impact.

Main Methods:

• Exergy, exergoeconomic, and exergoenvironmental analyses were employed.
• A multi-objective optimization approach utilizing the particle swarm algorithm was applied.
• A decision-making method was used to select the final optimal solution from the Pareto set.

Main Results:

• The zeotropic mixture of cyclohexane/toluene demonstrated superior thermodynamic and economic performance.
• The benzene/toluene zeotropic mixture exhibited the highest environmental performance.
• ORC systems utilizing zeotropic mixtures showed significant improvements in energetic, economic, and environmental metrics compared to pure fluids.

Conclusions:

• Zeotropic mixtures represent a promising alternative to pure fluids for enhancing ORC performance.
• Tailoring mixture composition allows for optimization across thermodynamic, economic, and environmental criteria.
• The study provides valuable insights for designing more efficient and sustainable ORC systems.