• Energy harvesting and power network architectures for the multibody advanced airship for transport high altitude cruiser-feeder airship concept

      Smith, Tim; Bingham, Chris; Stewart, Paul; Allarton, R.; Stewart, Jill; University of Lincoln (Institution of Mechanical Engineers, 2013-01-09)
      This article presents results of preliminary investigations in the development of a new class of airship. Specific focus is given to photo-electric harvesting as a primary energy source, power architectures and energy audits for life support, propulsion and ancillary loads to support the continuous daily operation of the primary airship (cruiser) at stratospheric altitudes (similar to 15 km). The results are being used to drive the requirements of the FP7 multibody advanced airship for transport programme, which is to globally transport both passengers and freight using a 'feeder-cruiser' concept. It is shown that there is a potential trade off to traditional cost and size limits and, although potentially very complex, a first-order approximation is used to demonstrate sensitivities to the economics of the lifting gas. This presented concept is substantially different to those of conventional aircraft due to the airship size and the inherent requirement to harvest and store sufficient energy during 'daylight' operation to guarantee safe operation during 'dark hours'. This is particularly apparent when the sizing of the proposed electrolyser is considered, as its size and mass increases nonlinearly with decreasing daylight duty. The study also considers the integration of photovoltaics with various electrical architectures, in safety critical environments. A mass audit is also included that shows that if the electrolyser was omitted in such systems, the overall impact will be small compared to structural and propulsion masses. It should be noted that although the technology bias is application specific, the underlying principles are much widely applicable to other energy harvesting and power management sectors.
    • Primary and albedo solar energy sources for high altitude persistent air vehicle operation

      Smith, Tim; Trancossi, Michele; Vucinic, Dean; Bingham, Chris; Stewart, Paul; University of Lincoln; Sheffield Hallam University; Vrije Universiteit Brussel; University of Derby (Multidisciplinary Digital Publishing Institute (MDPI), 2017-04-22)
      A new class of the all electric airship to globally transport both passengers and freight using a ‘feeder‐cruiser’ concept, and powered by renewable electric energy, is considered. Specific focus is given to photo‐electric harvesting as the primary energy source and the associated hydrogen‐based energy storage systems. Furthermore, it is shown that the total PV output may be significantly increased by utilising cloud albedo effects. Appropriate power architectures and energy audits required for life support, and the propulsion and ancillary loads to support the continuous daily operation of the primary airship (cruiser) at stratospheric altitudes (circa 18 km), are also considered. The presented solution is substantially different from those of conventional aircraft due to the airship size and the inherent requirement to harvest and store sufficient energy during “daylight” operation, when subject to varying seasonal conditions and latitudes, to ensure its safe and continued operation during the corresponding varying “dark hours”. This is particularly apparent when the sizing of the proposed electrolyser is considered, as its size and mass increase nonlinearly with decreasing day‐night duty. As such, a Unitized Regenerative Fuel Cell is proposed. For the first time the study also discusses the potential benefits of integrating the photo‐voltaic cells into airship canopy structures utilising TENSAIRITY®‐based elements in order to eliminate the requirements for separate inter‐PV array wiring and the transport of low pressure hydrogen between fuel cells.