Predicting the optimum design of single stage axial expanders in ORC systems: Is there a single efficiency map for different working fluids?

Results show that the influence of the working fluid on the efficiency maps may be not negligible, and can be taken into account by including the working fluid critical temperature in addition to the size parameter and volumetric expansion ratio. Accordingly, a generalized efficiency map is obtained which is valid for any fluid, and can be easily integrated into a comprehensive thermodynamic cycle analysis and optimization to account for the real turbine performance.