If a liquid operating medium is expanded in a recipro-cating engine after heating under increased pressure, in theory, significantly higher process efficiencies can be realized (increase from 30% to 80%). This is due to the steam generation with simultaneous cooling of the liquid phase. In this way, the exergy losses of an external evaporator, as used in customary processes, are avoided. The form of the cycle, illustrated in a temperature-entropy-diagram (T-s-diagram), reminds of a triangle.

In order to prevent the entry of the liquid phase in the cylinder chamber, a cyclone is connected upstream to phase separation. Computational fluid dynamics (CFD) simulate and then opimize the precipator efficiency of the liquid phase in the cyclone. It is about to achieve the highest possible precipitation and an almost complete load change. Compared to the above processes for the use of low-temperature heat the triangular process has the further advantage that it can be already used at very small amounts of waste heat. Reciprocating engines can be used under 1kW of electrical power, whereas turbines can be used energetically reasonable only at ratings higher than 100 kW.

The Institute of Technical Thermodynamics and Refrigeration Technology (KIT), the Institute for Reciprocating Engines (KIT) and the MOT GmbH together with the European Institute for Energy Research optimize the prototype of a reciprocating engine in order to implement the new triangular process successfully.

Project Operation:
EIfER Europäisches Institut für Energieforschung EDF-KIT EWIV
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