A Critical Overview of Working Fluids in Organic Rankine, Supercritical Rankine, and Supercritical Brayton Cycles Under Various Heat Grade Sources

Abstract

The Organic Rankine Cycle (ORC), Supercritical Rankine Cycle (SRC), and Supercritical Brayton Cycle (SBC) are three power cycles that are systematically investigated in the present paper, with particular emphasis on the different types of working fluids that are employed in each cycle and their influence as well as potential opportunities for enhancing the efficiency and thermal performance of power generation systems. The Organic fluids, the refrigerants, and the gasses are all taken into consideration as prospective working fluids in the study. The results demonstrate the distinct advantages and disadvantages of each cycle, with the ORC being best suited for low-temperature recuperation of waste heat, the SRC for operations requiring medium temperatures, and the SBC for high-temperature energy production. This research provides valuable insights regarding the selection of working fluids, considering various factors such as system parameters, environmental impacts, and thermodynamic efficiency. This study also discusses the recent findings on the utilization of organic working fluids, zeotropic mixtures, and nanofluids in these cycles, as well as provides a detailed summary of current trends and developments made in the field. Optimization of different working variables and the utilization of certain changes of working fluids for improving cycle efficiency is also reviewed. This study is motivated by the ongoing energy crisis and the necessity for alternate energy sources, particularly for the transformation of low-quality heat sources. Finally, the potential impact of this research on the scientific community lies in its ability to assist researchers and engineers in making well-informed decisions regarding the selection of the optimal operational fluid for a specific power cycle. Furthermore, this connection between power industries and working fluid selection highlights the relevance of this study to practical applications within the field.