Exergy analysis of sub-critical organic Rankin cycle for the energy utilization of biomass

Abstract

In this paper, an exergy analysis of the organic Rankin cycle for the utilization of biomass energy with working fluids m-xylene, MDM, toluene and a mixture (toluene/MDM/m-xylene) was carried out in a 33/33/33 ratio. The effects of thermodynamic properties of working fluids and mixtures on ORC performance with the regenerator were analyzed, and the thermodynamic properties of working fluids and mixtures were optimized by the exergy efficiency of ORC as an objective function using a genetic algorithm. The optimal performance values of the ORC cycles are compared and analyzed under the same heat source conditions and defined boundary conditions. The experimental analysis of the ORC shows that biomass energy is more suitable for m-xylene and toluene because compared to MDM (OMTS) and mixture (toluene/MDM/m-xylene) there are more values of exergy efficiency and thus less total exergy losses.

Keywords

• exergy
• organic Rankin cycle
• biomass
• working fluid