This paper presents thermodynamic analyses of a two-stage organic Rankine cycle (ORC) for solar thermal power generation. The effects of the operational parameters (i.e. high-pressure stage evaporating temperature, low-pressure stage evaporating temperature, solar collector outlet temperature and solar irradiation) on the SORC system performance (net power generation, overall system thermal efficiency, exergy efficiency and total thermal conductance) were investigated. The results indicated that there exist optimal high-pressure stage evaporating temperature and solar collector outlet temperature for maximizing the power generation, energy efficiency and exergy efficiency of the SORC system. As the solar irradiation and low-pressure stage evaporating temperature increase, the net power generation, overall system thermal efficiency and exergy efficiency increase.
Keywords Solar power; ORC; Thermodynamics; Two-stage evaporation.