Design and Optimization of a Waste Heat Recovery Organic Rankine Cycle System with a Steam–Water Dual Heat Source

Abstract

The organic Rankine cycle (ORC) system in plants, powered by dual steam–water heat sources, has significant power generation potential and practical research value. Herein, the conditions of 700 kPa saturated steam and 650 kPa, 90 °C water heat source are considered. Four configurations of steam–water dual heat source waste heat recovery ORC systems are proposed. The independent parameters affecting the net output power of the system are obtained by developing a mathematical model and optimizing it using the particle swarm optimization method. The results show that the location of the pinch‐point temperature difference in various ORC loops and the allowable working pressure of the heat exchanger are determinants of independent parameters. The net output powers of the conventional dual‐loop ORC (CD‐ORC), single‐loop ORC (S‐ORC), split‐flow dual‐loop ORC (SFD‐ORC), and split‐flow triple‐loop ORC SFT‐ORC systems under the optimal design parameters are 2415.73, 2168.6, 2599.62, and 2716.75 kW, respectively. In addition, S‐ORC has the highest exergy efficiency of 55.17%. SFD‐ORC and SFT‐ORC have ≈48% exergy efficiency, and CD‐ORC has the lowest exergy efficiency of 45.33%.

Investigation of low-GWP working fluids as substitutes for R245fa in organic Rankine cycle application

“…Results indicated that the net power significantly raised with the expander size, which had a slight effect on the thermal efficiency of the ORC system. Employing a particle swarm optimization algorithm, Wang et al [ 21 ] studied the thermodynamic and economic models of split-flow dual- and triple-loop organic Rankine cycle systems. It was found that the triple-loop system's net power exhibited superior to that of the dual-loop system by 7.9 %.…”