The Organic Rankine cycle (ORC) is named for its use of an organic, high molecular mass fluid

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 with a liquid-vapor phase change

Phase transition

A phase transition is the transformation of a thermodynamic system from one phase or state of matter to another.A phase of a thermodynamic system and the states of matter have uniform physical properties....

, or boiling point

Boiling point

The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....

, occurring at a lower temperature than the water-steam phase change. The fluid allows Rankine cycle

Rankine cycle

The Rankine cycle is a cycle that converts heat into work. The heat is supplied externally to a closed loop, which usually uses water. This cycle generates about 90% of all electric power used throughout the world, including virtually all solar thermal, biomass, coal and nuclear power plants. It is...

 heat recovery from lower temperature sources such as biomass combustion, industrial waste heat

Waste heat

Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...

, geothermal heat, solar ponds etc. The low-temperature heat is converted into useful work, that can itself be converted into electricity.