Kalina Cycle

The Kalina cycle is a thermodynamic process for converting thermal energy into usable mechanical power, developed by Alexander Kalina, that uses a working fluid made of two components with different boiling points, commonly water and ammonia, instead of a single pure fluid. Because the mixture boils and condenses over a range of temperatures rather than at one fixed point, the cycle extracts more heat from its source and rejects less to its sink than a comparable Rankine cycle, reaching efficiency close to a combined cycle plant with less mechanical complexity. It is used to recover waste heat from steel mills, oil refineries and cement plants, and to generate power from geothermal and solar heat sources; installed examples include a 3.6 megawatt unit at the Kashima Steel Works in Japan running since 1999 and a 3.4 megawatt geothermal plant at Unterhaching in Germany commissioned in 2009.