Effect of Working Fluids on Organic Rankine Cycle for the Recovery of Low-Grade Waste Heat

This paper presents an analysis of the basic organic Rankine cycle (ORC) using five types of working fluids: one wet fluid (R717), two isentropic fluids (R11 and R12) and two dry fluids (benzene and R113) with boiling points ranging from -33,35℃ to 79,85℃, to convert waste energy to power. These organic fluids are analyzed and compared, in the order to determine with which of them the best performance can be obtained. The evaluation was performed using a combined first and second law of thermodynamics and varying certain system operation parameters at saturation conditions. Results from these analyses have shown that the higher system thermal efficiency was obtained with the working fluids R11 and R113 compared with the others working fluids. In addition, the fluid that shows the best thermal efficiency is the one that the highest boiling point.