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L. Benda:
"Design of a supercritical CO2 test rig";
Betreuer/in(nen): A. Werner, G. Klemencic; Institut für Energietechnik und Thermodynamik, 2017.

Waste heat utilisation has become a major topic in times of the energy revolution. Technologies like the Organic Rankine Cycles (ORC) could increase energy sustainability massively. ORC and other comparable processes have, however, significant downsides, such as hazardous working fluids and high investment costs. This fact limits the number of profitable ORC and Steam Rankine Cycles (SRC) plants in industry. A new thermodynamic cycle which uses supercritical CO2 (sCO2) as working fluid offers the same energy efficiency at much lower investment costs. Unfortunately, sCO2 cycles for power generation have not yet been fully developed and investigated. In order to achieve more knowledge about these cycles, the Institute for Energy Systems and Thermodynamics started the project sCO2.
The aim of this master´s thesis was to design a concept for a simple thermodynamic sCO2 cycle. Generally, this thesis consists of three major parts, starting with a short summary on the potential of sCO2 waste heat utilisation in an industrial cement plant. In this compilation several common processes are applied on the waste heat sources of the cement plant.
The second part of this thesis deals with basic and detail engineering of the thermodynamic cycle, and is split into two project phases. Phase I is focussed on a simple cycle which consists of heater, throttle, cooler and pump. In this project phase the component and process behaviour should be investigated. Another important aim of phase I was the design of a process control system, which allows process operation at certain conditions. Moreover, a mere double pipe heat exchanger was designed, in order to investigate the sCO2 heat transfer potential. The designed cycle can also be used for heat displacement purposes. Furthermore, the test rig can reach pressures and temperatures up to 240 barg and 450 °C. The maximum thermal heat input is roughly 200 kW. In phase II, which is no major part of this thesis, compressor, turbine and recuperator will be added, in order to complete the cycle.
The third and last part of this thesis is short compilation of necessary future tasks. Since detail engineering is a broad field and would therefore exceed the scope of this thesis, further steps like 3D engineering and complete safety engineering are only mentioned and described. Nevertheless, this part gives the reader and the future engineer a clue of the tasks, which still need to be done to achieve a fully operational sCO2 test rig.

Waste Heat, Supercritical CO2 (sCO2), Energy Efficiency