Analysis of Power Generation Performance of ORC System With/Without Pump in Single/Dual Pressure Mode

With the rapid development of society, energy issues are becoming increasingly prominent. The organic Rankine cycle (ORC) is an effective means of recovering low-grade waste heat and saving energy. In this paper, four ORC systems, i.e., with/without pump and single/dual pressure, are established. The analysis of power generation performance was carried out for the four systems. Specifically, the power generation and exergy efficiency of these systems under different working conditions were compared. First, under the design conditions, the optimal evaporation temperature and the optimal flow rate of working fluid were obtained with the power generation as the optimization goal. Then with the optimal design parameters, the off-design performance of the four systems was investigated when operating with fluctuating heat source temperature and in different seasons. The simulation results showed that the dual-pressure pumpless system has the greatest power generation performance but the most complicated structure and control strategy.