Investigating and comparing the various refrigerant fluids using organic Rankine cycle

In this investigation, the thermodynamic first and secondlaw analysis to look at the use of the organic Rankine cycle to convert the waste energy from low-grade heat sources into electricity. The organic working fluids were selected in order to investigate the relationship between fluid boiling point temperature and organic Rankine cycle performance. The R124, R245fa, R21, R134a, R123, and R13 were selected as the working fluids for investigations and their boiling points ranges from 43 to 48 oC.The results are compared to water samples collected in similar conditions. A few system operational parameters are changed to perform a combined first- and second-law analysis at various reference temperatures. The results indicate that Organic Rankine Cycles (ORC) using R13 has the highest efficiency of all the organic fluids in the temperatures analysis. R123, R13, and R245fa revealed the maximum efficiency at the temperatures between 380 and 430 K, respectively, while isobutane shows the highest efficiency at the temperatures below 380 K. In addition to that the organic fluid's boiling point has the major influence on the thermal efficiency of thesystem. KEY WORDS: Heat energy, Refrigerants, Organic fluids, Rankine cycle and efficiency Bull. Chem. Soc. Ethiop. 2025, 39(10), 1909-1917. DOI: https://dx.doi.org/10.4314/bcse.v39i10.3