The working principle of the organic Rankine cycle is the same as that of the Rankine cycle: the working fluid is pumped to a boiler where it is evaporated, passed through an expansion device (turbine, screw, scroll, or other expander), and then through a condenser heat exchanger where it is finally re-condensed.

thermal power plant works on principle of the Rankine Cycle shown in Fig. 2[5]The cycle consists of four processes: (1-2) Isentropic compression on pump; (2-3) Constant pressure heat addition in a boiler; (3-4) Isentropic expansion in a turbine; (4-1) Constant pressure heat rejection in a condenser.

In thermodynamics, a temperature–entropy (T–s) diagram is a thermodynamic diagram used to visualize changes to temperature (T ) and specific entropy (s) during a thermodynamic process or cycle as the graph of a curve.

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.