System technology
Research on innovative systems includes system analysis, steady-state and dynamic system modeling, basic and detailed engineering, system construction, system testing, and the evaluation of results for subsequent system application. The development of fuel cell systems for on-board power supply at IET-4 is aligned with the definition of a technology readiness level, as it is generally used in the aerospace industry. The system work in various funded projects is essentially based on market maturity level 5, although the development of the reactors already shows a higher level of maturity. At IET-4, subsystems for fuel gas generation are developed and tested and integrated systems with fuel cell stacks are set up. In the future, hybrid systems will be developed for some applications.
The IET-4 follows the concept of testing components and systems in so-called modules. All laboratory components such as measuring instruments, valves and controllers that are necessary for scientific and technically oriented investigations are installed in the module. The actual system with its components is built in so-called packages. A package contains only those components that are necessary for later operation in an application. This results in a clear visibility of the components.
cFuel gas generation systems in six generations with a thermal output of up to 28 kW were designed and characterized at IET-4. Furthermore, an integrated HT-PEFC system with fuel gas generation for 5 kWe was developed, constructed and tested. The system was successfully operated with the fuels GtL kerosene, BtL diesel and premium diesel (Aral Ultimate) and achieved a maximum output of 5.5 kWe.
In order to ensure a needs-based power supply on board a vehicle, the fuel cell system, which is equipped with limited dynamics, is supported by a highly dynamic battery system. Hybridization using a suitable battery ensures that the fuel cell system can be started up more quickly and is protected from harmful operating situations and strong load fluctuations. The hybrid system makes it possible to cover the peak load demand, which is only required for short periods, using the battery. This allows the fuel cell system to be designed more compactly and efficiently.
The results of research and development work in the field of fuel gas generation for fuel cell systems have been incorporated into the development of a compact fuel cell system with diesel reforming in the 7.5 kWe class. The APU System S2 was constructed using multifunctional reactors for fuel gas generation. Commercially available stacks and peripheral components were used. The self-sufficient system has a high energy density of 35 We/l and a start-up time of 22 min. The expertise gained from these activities is available for future projects.