Direct Optimization for Cycle Working Fluids Using a Thermodynamic Generalized Fluid Approach

Fluid blends as working fluids in solar thermal power cycles have been shown to promise an even higher efficiency than pure fluids. Rather than exploring specific blends, we propose an approach in which we directly optimize for a working fluid characterized in terms of the fluid critical point following the fundamental corresponding states principle. This direct approach allows to identify the optimal fluid one would require for given cycle boundary conditions. The approach can be applied to any given cycle; the suitable fluid selection is then performed in a second step after the desired optimal properties are identified.