Triangle Cycle: thermodynamic cycle with the theoretically highest efficiency
EIFER will present the new thermodynamic process "Triangle Cycle" for the conversion of low temperature heat into electrical power at the exhibition "Woche der Umwelt". Invited by Federal President to Bellevue Palace in Berlin, 200 companies, institutions, research institutes, associations and initiatives have the opportunity to present their technologies, products, projects and concepts for a sustainable and efficient dealing with our resources (http://www.woche-der-umwelt.de/1872.html).
With the funding of Deutsche Bundesstiftung Umwelt (DBU) and Energie Baden-Württemberg AG (EnBW) EIFER has developed a new thermodynamic process for the conversion of low temperature heat into mechanical or electrical power. In comparison to the commonly used processes, like the ORC (Organic Rankine Cycle) or the Kalina-Process, EIFER’s new Triangle Process, can attain much higher electrical output and therefore has the potential to be economically successful.
The conversion of low temperature heat into mechanical and electrical power plays a major role in renewable energy, in fields like geothermal heat, solar thermal heat and industrial waste heat. Previously, thermodynamic processes like the Clausius Rankine cycle (CRC) the (ORC) and the Kalina-Process have been used to achieve this conversion. EIFER’s new process is based on the flash evaporation of a high temperature and pressurized liquid fluid inside the working chamber of a reciprocating engine. After the liquid is injected into the expansion unit, evaporation takes place and the vapor moves the piston. The heat for evaporation is provided by the liquid phase, which then cools down. The main advantage of the new process is simultaneous evaporation and expansion which results in avoiding the exergy losses of an external evaporator.
To prevent hydraulic shocks from occurring in the reciprocating engine, the liquid is injected into a pre-chamber. The pre-chamber is modeled as a cyclone to separate the liquid from the vapor. The main challenge in this project is to develop a cyclone design that is capable of providing high separation at a low inner (death) volume. Furthermore a valve technique has to be established that makes a complete alternation of load available. For better understanding of the cyclone behavior and the optimization of the cyclone design computational fluid dynamics (CFD) is used. EIFER and its partner ITTK (KIT) are the first to use CFD methods to simulate flow behavior inside the cyclone to optimize its geometry. EIFER cooperated with various KIT departments (ITTK, IFKM and ETI) and MOT GmbH, Karlsruhe, to develop a optimized prototype and to enable the Triangle Process.
"Woche der Umwelt":