CFD Evaluation of the Effect of Ejector Geometries and Different Working Fluids in the Efficiency of Organic Rankine Cycle with Ejector

The introduction of Organic Rankine Cycle (ORC) in power generation brings hope to reduce carbon footprint from the typical Rankine Cycle while producing useful power utilizing the renewable energy. Given this, the improvement on the ways to enhance the ORC thermal efficiency and power output have been in constant topic nowadays. One of which is the Organic Rankine Cycle with Ejector (EORC) where it employs an ejector between the expander and condenser to increase the fluid flow and pressure difference across the expander, improving the expander work output. In this study, the investigation focuses on the effect of ejector geometry and working fluids (i.e. R245fa, Isobutane, and R134a) in the EORC thermal efficiency through ejector simulation using ANSYS 2021 student version. The ejector geometric evaluation is composed of forty designs for each working fluid. The simulation was made on each design number by varying one ejector geometry while keeping the rest of the dimension's constant. The study found that the addition of an ejector to the ORC improved the system net power output by more than 100% but decreases the thermal efficiency by 69% at the least.