Thermodynamic Performance Analysis of an Improved Two-Stage Organic Rankine Cycle

Abstract

In order to improve the two-stage organic Rankine cycle of two heat exchanges of exhaust gas, a two-stage organic Rankine cycle with a regenerator is proposed. Toluene, benzene, cyclohexane and R245fa were selected as the working fluids of the cycle. The thermal efficiency, exergy efficiency and net output power of the cycle were selected as the objective function of the system. The influence of the regenerative performance on the thermodynamic performance of the system was analyzed. The influence of the temperature change of the primary heat exchange outlet on the thermodynamic performance of the system is discussed. The research shows that the regenerator can increase the net power and thermal efficiency of the cycle output. For the selected working fluid, as the efficiency of the regenerator increases, the thermal efficiency of the cycle and the net output power increase. When the primary heat exchange outlet temperature of the exhaust gas increases, the net output power and the exergy efficiency of the cycle increase. For the selected working fluid, when the exhaust heat exchange outlet temperature was increased from 410 K to 490 K, the net output power of the cycle increased up to 10.76 kW, and the exergy efficiency increased up to 7.85%.