Research Outputs

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Now showing 1 - 10 of 13
  • Publication
    Development of Innovative Hydrogen and Micro Energy Solutions at the Austrian Research Centers
    (American Institute of Aeronautics and Astronautics, 2008-07-28) ;
    Tajmar, Martin 
    ;
    Dudzinski, Piotr 
    ;
    Reissner, Alexander 
      180  496Scopus© Citations 5
  • Publication
    Innovative Hydrogen Storage in Microspheres
    (2008-02-20) ;
    Tajmar, Martin 
      107  1
  • Publication
    Radiation Shielding Using Micro Cavities Filled with Highly Pressurised Gas
    (2012-11-29)
    Usually, hydrogen is stored under high pressure, in chemical compounds or in its liquid state requiring very low temperatures. Gaseous hydrogen can be stored in hollow glass microspheres (5 μm to 200μm diameters) under high pressure (350 bar to 700 bar). The sphere-wall is impermeable for hydrogen at ambient temperature; the heating of the spheres increases the diffusion of hydrogen through the wall. The Aerospace Engineering group of the FOTEC GmbH developed an innovative process for the European Space Agency that combines the storage concepts of hollow glass microspheres with chemical hydrogen storage. The combination of these two principles provides the advantages of both but cancels their respective drawbacks. Our analysis shows that such a system can reach hydrogen storage capacities of up to 10wt% in theory. This value depends on the sphere dimensions, the weight of the spheres, the hydrogen pressure, and the nature of the utilised hydride. The expertise gained in the course of the extensive research on gas storage in hollow microspheres lead to new applications for such a system. One of these applications is the use of microspheres filled with highly pressurized gas as radiation shielding material. Since hydrogen is very effective in absorbing the energy of highly energetic particles with minimal generation of secondary particles, it is particularly suitable for radiation shielding. Effective radiation shielding materials therefore often incorporate high concentrations of hydrogen. By using glass microspheres, it becomes possible to collect large amounts of hydrogen atoms with a relatively high gravimetric as well as volumetric density. It is also possible to store other light gases in the microspheres like deuterium or helium, in order to customize the absorption properties of the material. Preliminary calculations show that this technique can be used as radiation shielding with significant mass savings in respect to conventional materials. In comparison to aluminium for example, the hydrogen filled microspheres can shield high-energy protons and ions with 30% to 40 % increased efficiency. Also bremsstrahlung, secondary neutrons and gamma rays can be significantly reduced. Due to the fact that the material can be easily adapted to any given form, the possible terrestrial applications include: radiation shielding of aircrafts, shielding of computer and electronics, radiation shielding in research facilities as well as on medical sites, but also protective clothing for PCRs (Competent Person in Radioprotection). Considering the possibility to produce large amounts of such a material with relatively low cost, a broad industrial interest for such a light-weight and ultra-dense radiation shielding material can be expected. Also, the considered material is easy to handle with respect to safety and flexibility. Space technology could be used to protect the environment and the population against radiation. To make this technology available for terrestrial applications, the first step is the detailed assessment of the physical processes of gas-filled microspheres in a radioactive environment. It is then possible to investigate the best combination of gas species, microsphere properties, coating layer and support structure or binding material for different applications. The second step is the production of a prototype layer material based on filled microspheres and the testing of the radiation shielding properties of the new material. The Aerospace Engineering group is specialised in the development of micro propulsion and gas storage systems for space application. It has a long record of successful projects performed on behalf of the European Space Agency. As research and service provider of the University of Applied Sciences Wiener Neustadt, it is the ideal hub for educational, industrial and scientific projects. A test facility to test the catalyst efficiency and the thermal properties of the coated microspheres as well as filling the microspheres with different gases is available.
      96  1
  • Publication
    Metal Hydrides as Hydrogen and Heat Storage System for Satellite Applications
    (2013-06-16)
    Reissner, Alexander 
    ;
    ;
    Hummel, Stefan 
    ;
    Scharlemann, Carsten 
    ;
    Tajmar, Martin 
      122  1
  • Publication
    Innovative Hydrogen Storage Solutions for Aerospace Applications
    (Jülich GmbH, 2010) ;
    Reissner, Alexander 
    ;
    Schmid, G. 
    ;
    Tajmar, M. 
      142  2224
  • Publication
    Micro-Propulsion and Power Developments at AIT
    (2009-01-12) ;
    Tajmar, Martin 
    ;
    Scharlemann, Carsten 
    The increasing application of micro-satellites (from 10 kg up to 100 kg) as well as CubeSats for a rising number of various missions demands the development of miniaturized propulsion systems. The Austrian Institute of Technology is developing a number of micropropulsion technologies including both electric and chemical thrusters targeting high-performance at small scales. Our electric propulsion developments include FEEP thrusters with thrust ranges from μN to mN using highly-integrated clusters of indium Liquid-Metal-Ion Sources providing ultralow thrust noise and long-term stability, as well as the development of a micro PPT thruster enabling pointing capabilities for CubeSats. For chemical thrusters, we are developing novel micro-monopropellant thrusters with several hundred mN as well as a 1-3 N bi-propellant micro rocket engine using green propellants and high specific impulse performance. This paper will give an overview of our micropropulsion developments highlighting performance as well as possible applications.
      102  2
  • Publication
    Characterization of the Reversible Hydrogenation Properties of Sodium Alanate under various contaminated Hydrogen Conditions
    (2013-06-17)
    Reissner, Alexander 
    ;
    ;
    Hummel, Stefan 
    ;
    Scharlemann, Carsten 
    ;
    Tajmar, Martin 
      122  1
  • Publication
    Development of Innovative Micro Power Converter Technologies at the Austrian Institute of Technology
    (American Institute of Aeronautics and Astronautics, 2009-08) ;
    Vasiljevich, Ivanhoe 
    ;
    Dudzinski, Piotr 
    ;
    Tajmar, Martin 
    ;
    Gerger, Joachim 
    Waste heat is a primary source of energy loss in many aerospace and terrestrial applications. The Austrian Institute of Technology (AIT) is presently developing two different types of micro power converters, promising high efficiencies in their respective application areas. The first converter is based on an innovative thermoacoustic Stirling engine concept without moving parts. Such a maintenance-free engine system would be particularly suitable for advanced Stirling radioisotope space power systems. The second converter is based on microturbines to use exhaust-gases for improving the overall efficiency for a number of applications. This paper will summarize our efforts on micro power converter technologies.
      104  1Scopus© Citations 1
  • Publication
    Novel Hydrogen Storage Solutions for Space and Aerospace Applications
    (2011-05-15) ;
    Reissner, A. 
    ;
    Bichler, D. 
    ;
    Tajmar, M. 
    Novel hydrogen storage solutions are increasingly important for a number of future aerospace and space applications. The Aerospace Engineering Group of the fotec Forschungs- und Technologietransfer GmbH is presently developing an innovative hydrogen storage system based on high pressure hydrogen storage in microspheres. The hollow glass microspheres are loaded with up to 700 bar of hydrogen gas with a thermal process. The gas was released with a special heating wire. Such a system could be used as safety gas generator on satellites and airplanes. An additional space application for hydrogen filled microspheres seemed to be the use as additive in cryogenic liquid storage systems to enlarge the longtime durability. Further projects deals with new energy storage solutions to replace secondary batteries on satellites. We decided to approach this topic by directly coupling a fuel cell with a metal hydride based on Ti-doped sodium alanate. The power dissipation of the fuel cell can be used for desorption of hydrogen where heat is required, instead of being rejected by a heavy thermal control system. This advantage would be very interesting in order to obtain higher weight efficiencies which are especially important for space and submarine applications.
      197  546