Towards optimal mixtures of working fluids: Integrated design of processes and mixtures for Organic Rankine Cycles

Abstract Organic Rankine Cycles transform low-temperature heat from sustainable sources into electrical power. Exploiting the full potential of a source requires optimal combination and working fluid. Today, fluids are commonly pure components. However, mixtures can significantly improve process efficiency due to their favorable temperature-glide during evaporation condensation. In this work, we present method for integrated design fluid mixtures, so-called 1-stage Co ntinuous- M olecular T argeting C omputer- ided m ixture b lend d esign (CoMT-CAM D). CoMT-CAM D, physically-based perturbed-chain statistical associating theory (PC-SAFT) equation state is used model both, equilibrium transport properties mixture. A CAM D formulation enables us consider molecular structure mixture components as well its composition degrees freedom optimization. detailed sizing equipment allows optimize not only thermodynamic but also economic objectives. demonstrated an Cycle waste recovery. The identifies several million possible jointly with corresponding equipment, e.g., propane/diethyl ether maximizing net power output ( P = 295 kW ) or propene/propionaldehyde minimizing specific investment cost SIC 3479 € /kW ). presented rigorously analyze compared varying cooling medium systematically exploit Cycles.