Customized Small-scale ORC Turbogenerators– Combining a 1D-design Tool, a Micro-turbine-generator–construction Kit and Potentials of 3D-printing

orc2019 Tracking Number 9

Due to the various possible applications in the ORC waste heat recovery business i.e. different heat sources, heat flow rates, temperature levels, pressure levels and working fluids, it is not appropriate to design and build one standard turbogenerator to stock. Therefore, the authors developed a very flexible “micro-turbine-generator-construction-kit (MTG-c-kit)” by means of which a customized turbine generator can be designed and built for any required power output between 1 - 200 kW, for a wide range of working fluids and boundary conditions – quickly and cost efficiently. The architecture of this construction kit and its main features are introduced briefly in this paper. However, more focus is put on the developed 1D turbine design tool. It allows to design and optimize a single stage turbine for any fluid and any boundary conditions very quickly. The thermodynamic model and the applied loss models for the implementable axial impulse turbine or radial inflow cantilever turbine are discussed by means of a specific design example. Experimental results of two micro turbines, which were designed and built according to the above-mentioned approach, are presented and the agreement and discrepancies between measured and design data are discussed. In order to further accelerate and cheapen those customized micro turbine generators for small and low temperature applications, we provide an outlook of possibilities of additive manufacturing methods like 3D-printing of plastic turbine wheels for example. These new possibilities provide potential to improve the competiveness of small-scale ORC in waste heat recovery. A prototype of a simple turbine design with plastic 3D printed wheels has been manufactured and first tests are presented.