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.

ORC is the Rankine process, where instead of the water some organic compound is used as a flowing medium (toluene, isobutene, isopentane or silicon fluids). ORC is one way to generate electricity and heat in lower temperatures. Heat from evaporation of organic fluid is less than that of water.

Organic Rankine cycle (ORC) machines are used to convert low-temperature heat resources into power. Examples include systems making use of waste heat in a cogeneration system, low temperature geothermal electricity generation, solar ponds, and potentially OTEC.

Additionally, ORCs eliminate the need for full-time plant operators because they operate at lower pressures and do not need water chemistry maintenance. However, working fluid cost, decomposition, temperature limits are an organic Rankine cycle's primary disadvantages.