The Institute of Turbomachinery and Fluid Dynamics at Leibniz University Hannover has received the special award for "Climate Protection and Resource Efficiency" at the Steel Innovation Prize 2018, organized by the German Steel Federation. The Institute has developed a new turbine generator unit. With the expected regulation on CO2 limits for the commercial vehicle sector, manufacturers are under increasing pressure to accelerate vehicle electrification and increase the efficiency of conventional engines.
The turbine generator developed by the institute as a prototype, applies a technology to truck engines, which has so far been utilised mainly in large-scale systems. The promising approach increases the overall efficiency of commercial engines by using the residual heat contained in exhaust gas with the help of a downstream thermodynamic cycle. The Organic Rankine Cycle (ORC), named after the physicist William Rankine, is especially suitable for the technology. During the process, a fluid organic operating medium is pumped into a heat exchanger under high pressure and vaporised by waste heat subsequently. The steam is released into an expansion machine, whereby potential energy is transformed into mechanical work. Afterwards, the steam cools down in a condenser until it liquefies again.
The turbine generator unit, developed within the scope of a project by the Research Association for Combustion Engines (FW), enables the use of this technology for more efficient diesel engines in trucks. In order to save weight through a more compact design, the expanding part of the module is realised in form of a single-stage, axial impulse turbine. The generator, which is linked to the turbine stage, provides electrical energy for the auxiliary unit of vehicles.
Bench tests at the joint test facility of the Institute for Power Plant Technology and the Institute of Turbomachinery and Fluid Dynamics at Leibniz University Hannover, located at the Energy Research Center of Lower Saxony in Goslar, prove the efficiency of the turbine generator unit. In this way, a turbine peak power of 7,6 kW and an efficiency of 57 percent was achieved. This corresponds to a potential saving of fuel and CO2 emissions of three percent. Further savings are attained in higher load ranges, for which numerical fluid mechanics calculations predict a turbine performance of up to 17 kW. The new module has the potential to significantly increase the overall efficiency of commercial vehicles. This will be an important contribution towards climate protection and the more efficient use of resources.
Note to editors:
For further information, please contact Prof. Dr.-Ing. Jörg Seume, Head of the Institute of Turbomachinery and Fluid Dynamics (Tel.: +49 511 762 2733, email: seume@tfd.uni-hannover.de).
