Organic Rankine Cycle at Indian Institute of Science (renewable energy research).

3-dimensional computer-aided design of entire experimental setup (made by Shashanth S. K., project assistant, using PTC Creo). 3-dimensional computer-aided design: magnified view of part of ORC setup. Schematic of ORC experimental setup.

Many organic compounds require lower temperatures for vaporization. Temperature vs. specific entropy diagram of water and a few organic compounds. Hence, unlike H 2 O-based Rankine Cycle, an Organic Rankine Cycle can use heat sources of relatively lower temperatures (e.g. less than 300  ⁰C) for low-scale power generation (few kilo watts).

Rankine cycle is a thermodynamic cycle used in commercial thermal power plants... Main components of Rankine cycle: pump (1 - 2), boiler (2 - 3), turbine (3 - 4), condenser (4 - 1). Image from https://upload.wikimedia.org/wikipedia/commons/0/00/Rankine_cycle_layout.png The working fluid is H 2 O (water / steam). Image from textbook "Fundamentals of Thermodynamics" by Borgnakke and Sonntag (8th edition, Wiley). As shown above, high pressure can be above 90 bar, and low pressure can be around 0.05 bar High temperature may be around 500  ⁰ C, and low temperature may be a little more than ambient temperature (e.g. 45  ⁰ C). This is a large-scale power production cycle (net output of several megawatts).