Hydrogen based Auxiliary Power Unit (APU)
The actual satellite market trends toward satellites with increasing performances, but at the cost of a higher energy requirement call for a new generation of micro power sources. The aim of this project is to realise a power source with a higher energy density than current batteries and with short recharging time. Further more the integration of the power system inside the structure should be possible. The use of such multifunctional structure reduces the weight of the storage system and increases the structure stability. Fuel Cells in combination with innovative hydrogen and oxygen storage have high chemical conversion efficiency (such as batteries) and high energy density (in contrast to state of the art lithium batteries). Alternatives are micro-turbine and micro-piston based engines but they are not suitable as micro power sources due to the noise and vibrations (they produce for operation) and the lower efficiency (in contrast to fuel cells).
One of the most interesting applications for the metal-hydride battery replacement are all types of satellites (micro, small, intermediate, large). The presently used lithium-ion batteries are not suitable for power ranges exceeding 5 kW. On the other hand, the trend to more complex missions and larger, multi-functional satellites, requires high power systems. Due to its ability to supply power up to 30 kW, the suggested technology has the potential to fully replace the lithium-ion battery systems and enables missions with power requirements exceeding by far those presently executed.
The scalability and modularity of fuel cell systems however opens up other, much larger terrestrial markets. This includes in particular the automotive area but also mobile computers and all other high power energy applications. The production of hydrogen is independent of the location and the suggested system could therefore be the basis of an independent, since replenish able, power supply system even in remote areas. Furthermore, due to its potential for miniaturization it will be applicable in all systems, where a portable efficient high energy density power system is required.
ARC is developing a hydrogen based Auxiliary Power Unit (see Fig. 1) combined with a novel hydrogen and oxygen storage system.
Fig 1.: Auxiliary Power Unit
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right: Combined Hydrogen-Water Storage Vessel
marcus.keding@ait.ac.at