Performance evaluation of the supercritical organic rankine cycle (SORC) integrated with large scale solar parabolic trough collector (SPTC) system: An exergy energy analysis

Abstract

In this article, exergy and energy analysis of supercritical organic Rankine cycle integrated with solar parabolic trough collector (SPTC) is presented. Proposed working fluids are R600a, Toluene, R152a, isobutene, and cyclohexane for the supercritical ORC. Performance parameters including exergy efficiency, rate of exergy destruction, improvement potential, fuel depletion ratio, irreversibility ratio and expansion ratio were also examined in this study. The results of the study demonstrate that exergy efficiency increases continuously as both the solar irradiation intensity and inlet pressure of turbine increases, and R600a gives the maximum exergy efficiency among the others, i.e. around 96.09% at GB = 0.95 kW/m2 and 94.37% at 17 MPa. In addition, the exergy destruction rate decreases continuously with the increase in solar irradiation intensity as well as inlet pressure of the turbine, and it has been observed that the maximum exergy destruction rate occurs in the solar collector, which is around 80% of the total exergy destruction rate of combined SPTC‐SORC. Nonetheless, R600a has the minimum value of the exergy destruction rate, i.e., 1527 kW at GB = 0.5 kW/m2. Alternatively, cyclohexane shows a maximum exergy destruction rate, which is around 3794 kW at GB = 0.5 kW/m2. Also, SORC turbine and recuperator have a countable value of the exergy destruction rate. Finally, this study revealed that exergetic parameters like improvement potential, fuel depletion ratio and irreversibility ratio are found to be 11,859 kW, 0.579, and 0.9296 for the parabolic trough collector in the combined R600a based SPTC‐SORC system. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 891–899, 2018