The effect of recuperator on the efficiency of ORC and TFC with very dry working fluid

Organic Rankine Cycles (ORC) and Trilateral Flash (TFC) are very similar power cycles; ideally, they have a reversible adiabatic (isentropic) compression, an isobaric heating, isentropic expansion cooling. The main difference is that for ORC, the heating includes full evaporation of working fluid (prior expansion); therefore, starts in saturated or dry vapour state, while TFC, terminates upon reaching liquid states. Therefore, TFT, liquid/vapour state (in bubbly dispersed with droplets), requiring special two-phase expander. Being ORC more “complete” cycle, one would expect its thermodynamic efficiency always higher than between same temperatures using fluids. Surprisingly, it was shown fluids, TFC can exceed basic (i.e. recuperator- superheater-free) choosing sufficiently high (but still subcritical) maximal cycle temperature. Therefore these cases, (having simpler heat exchange unit heating) be better choice ORC. presence recuperator influence situation; by recovering proper percentage remaining (after expansion), reach even pass TFC.