Investigation on the optimal condensation temperature of supercritical organic Rankine cycle systems considering meteorological parameters

Organic Rankine cycle (ORC) system is one of the important technologies for waste heat utilization with mid-to-low temperatures. Compared to the steam Rankine cycle (SRC) system, the fluctuation of the condensation temperature due to seasonal and meteorological factors has a more significant effect on the performance of ORC systems since the temperature difference between evaporation and condensation is relatively smaller. In this paper, supercritical ORC thermodynamic models under design and off-design conditions are established. The condenser is divided into pre-cooling section and condensation section. The simulation results show that the net output power and thermal efficiency decrease with the rise of cooling water inlet temperature in the condenser. It is found that the effect of higher and lower cooling water inlet temperature compared to the design condition on the system performance is asymmetric. In addition, considering the meteorological parameters, the optimal design condensation temperatures of ORC system in Beijing, Shanghai and Guangzhou are about 30-34 °C, 34-38 °C and 38-42 °C individually. Present results on the suitable design condensation temperature can provide reference for the practical application and optimization of ORC systems.