Technical options for Organic Rankine Cycle systems A supercritical or transcritical cycle is a cycle with a maximum pressure higher than the critical one. Working fluid is heated up from subcooled liquid to superheated vapor with a smooth transition above the critical point.

An organic Rankine cycle (ORC), is fundamentally the same as a steam Rankine cycle; however, it uses a lower boiling point organic fluid to better match its operation to lower temperature heat sources. ORC systems can achieve better efficiencies than steam turbines for smaller systems (less than a few MW_e).

The supercritical ORC aims to enlarge the expansion in the turbine to generate more power such that the evaporation process occurs above the critical pressure of the working fluid. In a regenerative ORC, a heat exchanger is placed between the fluid exiting the turbine and that exiting the pump.