Comparative Assessment of Solar Energy Based Transcritical CO2 Rankine Cycles for Different Layouts

Abstract

In this study, different transcritical CO2 Rankine (tCO2-RC) cycles with vacuum tube solar collectors are examined. In this context, the transcritical CO2 Rankine cycle in different configurations, such as simple, regenerator, reheat, regenerator, and reheat, which is widely used in the literature, has been chosen. First, the energy and exergy efficiencies of the cycles were founded by performing thermodynamic analyzes of four various tCO2-RCs under certain operating parameters. Moreover, parametric studies were carried out according to the factors affecting the system performance, like turbine input temperature and input pressure of the turbine. Both analyzes and parametric studies were conducted utilizing the Engineering Equation Solver (EES) computer program. As outcomes of analyzes, the highest thermal efficiency was founded for the tCO2-RC with reheat and regenerator by 11.8%, and the lowest energy efficiency was calculated for the simple tCO2-RC and tCO2-RC with reheat by approximately 6.6%. While all tCO2-RCs' energy and exergy efficiencies increased with the rise of the turbine’s input pressure, the energy and exergy efficiency of all tCO2-RCs decreased with the rise of the pump’s input pressure.