Organic Rankine Cycles (ORC) are systems that can effectively recover low-grade heat for electric power generation. For ORC to be a viable technology, it should operate safely and efficiently under variable operating conditions due to exogenous and operating specifications changes.

The Rankine cycle is named after William John Macquorn Rankine, a Scottish polymath professor at Glasgow University. Heat energy is supplied to the system via a boiler where the working fluid (typically water) is converted to a high-pressure gaseous state (steam) in order to turn a turbine.

Rankine cycle is an ideal cycle of heat engine which uses water and steam as a working fluid to generate power with the help of a steam turbine. Process 1-2: Isentropic compression in Pump. Process 2-3: Constant pressure heat addition in the Boiler. Process 3-4: Isentropic expansion in Turbine.

The Rankine cycle is closed by a condenser (using cooling water) that convert saturated vapor at low pressure from the turbine generator into condensate, which is pumped back to the heat exchanger to restart the cycle.