The organic Rankine cycle (ORC) is a Rankine cycle that employs an organic fluid as working medium to generate power from lower temperature sources such as biomass combustion, industrial waste heat, and geothermal heat [1–5].

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.

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.

Financial analysis shows that the ORC system, including the cost of the unit plus the costs of installation and integration into the process, will cost approximately 4.8 Million USD. The payback period is 4 years.