ORC – Organic Rankine Cycles CHP
An ORG CHP system operates in much the same principal as a steam turbine however it uses a lower (or higher) boiling point fluid to function.
The technology operates by using low-grade heat to generate extra power. These can be driven by waste heat from conventional CHP or by normal boilers.
Technology is not classified as CHP if heat from a boiler-driven ORC is diverted for use. This phrase only applies if the ORC is driven by a conventional CHP and some heat is recovered before entering the ORC. This counts as CHP.
Recovering heat from the ORC cycle itself will not be practical in many cases as the temperature of the condenser is around 20°C, which is too low for most applications. Recovering heat between turbine stages would reduce an already low efficiency process.
Future ORC technologies are rumoured to use a working fluid with an increased boiling point such as oil, so heat recovered through the ORC process is more useful.