Design of a 1 kW Organic Rankine Cycle for teaching and research issues
Christian Dirk Bonk, Christoph Laux, Maximilian Rödder, Matthias Neef
Session: Poster session & Welcome drinks
Session starts: Wednesday 13 September, 17:30
Christian Dirk Bonk (University of Applied Sciences Düsseldorf)
Christoph Laux (University of Applied Sciences Düsseldorf)
Maximilian Rödder (University of Applied Sciences Düsseldorf)
Matthias Neef (University of Applied Sciences Düsseldorf)
This paper deals with the design of a micro-scale ORC plant for teaching and research including the development of an automated control concept. The aim is to provide a safe and environmentally acceptable micro-scale heat engine, which can be developed, implemented and used in university labs for the education of students as well as for small research projects.
The test rig allows for the support of several learning outcomes on a multi-disciplinary level particularly for the implementation and simulation of small power systems.
Special attention was given to the organic working fluid characteristics and its selection process. Above performance goals, favourable safety properties and low global warming potential were decisive in the selection of the novel organic fluid called 3M™ Novec™ 649. The performance and the fluid behaviour of Novec 649 in a micro-scale power cycle is of major interest and the research goal for the test rig presented in this paper.
Due to the expected power output of 1 kW a scroll expander is chosen as the generator drive for the micro plant.
In order to design the major parts of the ORC, the thermodynamic simulation software EBSILON®Professional was used. Therefore the supply temperature was set to 140 °C. As a result of the simulation, feasible expander inlet pressures spread from 5.5 bar to 8.5 bar. This leads to thermal efficiencies of the ORC in the order of 5 %. Adding a recuperator to the cycle system decreases the operating pressure range but in the end the thermal efficiency can be increased by 1.5 %-points up to 6.3 %.
Finally, an automated control concept is introduced, where the pump is controlled via the fill level measurement system.