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.

ORC: How it works In a typical ORC design, a thermal energy source feeds an evaporator to drive an expander or “reverse compressor”, which in turn generates the electricity. The provider of the heat can be natural, such as in the case of geothermal energy, or waste heat from any number of industrial waste heat sources.

Organic Rankine Cycle (ORC) power systems are nowadays an option for local and domestic cogeneration of heat and electric power. Very interesting are micropower systems for heat recovery from low potential (40-90 °C) waste and renewable heat sources.