Another application for a heat recovery steam generator is in diesel engine combined cycle power plants, where hot exhaust from a diesel engine is fed to a heat recovery steam generator to generate steam which in turn drives a steam turbine. The HRSG is also an important component in cogeneration plants. Cogeneration plants typically have a higher overall efficiency in comparison to a combined cycle plant. This is due to the loss of energy associated with the steam turbine.
A heat recovery steam generator consists of three major components. They are the Evaporator, Superheater, and Economizer. The different components are put together to meet the operating requirements of the unit.