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).

However, working fluid cost, decomposition, temperature limits are an organic Rankine cycle's primary disadvantages.

The organic Rankine cycle is is similar to the Rankine steam cycle, but uses an organic fluid such as refrigerants and hydrocarbons instead of water as the working fluid. The ordinary Rankine cycle uses thermal power to convert water to steam, which expands through a turbine in order to generate electricity.

New Working Fluids for Organic Rankine Cycles Hydrofluoroolefin (HFO) working fluids from Opteon™ deliver superior performance for organic Rankine cycles. With a substantially lower GWP than legacy working fluids, Opteon™ solutions are an optimal solution for waste heat recovery applications.