Keding, Marcus

Official Name
Keding, Marcus
Main Affiliation
Akademische Titel
DI
Email
marcus.keding@forschung-burgenland.at
Scopus Author ID
36468736300
Status
staff

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    Item type:Patent,
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    Innovative Hydrogen Storage Solutions for Aerospace Applications
    (Jülich GmbH, 2010)
    ;
    Reissner, Alexander 
    ;
    Schmid, G. 
    ;
    Tajmar, M. 
      163  447
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    Development of a µ-scale Turbine Expander for Energy Recovery
    (American society of mechanical engineers, 2009)
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    Dudzinski, Piotr 
    ;
    Tajmar, Martin 
    ;
    Willinger, Reinhard 
    ;
    Käfer, Klaus 
    Waste heat is a primary source of energy loss in many applications. A number of developments around a micro rocket engine at the Austrian Research Centers (ARC) promise innovative energy recovery and micro power generation solutions. Here we focus on the investigation of micro technologies for application in HVAC (heating, ventilating, and air conditioning) systems. The use of μ-scale turbine expanders for work recovery in transcritical CO2 heat pump processes has been identified as most interesting and promising for the application in HVAC cases. One of the main drawbacks of transcritical CO2 heat pumps is the lower COP (coefficient of performance) compared to conventional heat pump systems which originates from the non isothermal heat rejection in the gas cooler. This drawback can be compensated by utilizing the pressure difference between the high pressure and low pressure part of the heat pump for work recovery. This is feasible as the pressure difference is considerably larger in case of CO2 heat pumps compared to conventional systems. Work recovery can be realized by substituting the expansion valve between the high and low pressure side by an expansion machine. Due to the low flow rate of the working fluid, the turbine type is based on the Pelton turbine with specific two phase flow turbine blades. In addition to the turbine part a magnetic coupling, miniature bearings and a small scale generator are important parts of the system. Thermodynamic simulations showed an absolute microturbine power yield between 60 W and 150 W for a 2 kW heating system.
      1  147
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    Development of a Ti-doped Sodium Alanate Hydrogen Storage System
    (2009)
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    Reissner, Alexander 
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    Dudzinski, Piotr 
    ;
    Tajmar, Martin 
    A trade-off analysis regarding power supply on satellites, which was performed for the European Space Agency (ESA), suggested that fuel cells might be an interesting candidate to replace secondary batteries on satellites. The Austrian Research Centers (ARC) decided to approach this topic by combining a fuel cell with innovative chemical hydrogen and oxygen storage as well as integrating the oxygen storage system into a form that can be used as a structural element. Also an integration of the fuel cell into the hydrogen tank, and the resulting storage of dissipation heat, results in a reduction of the necessary thermal control system. These advantages are very interesting in order to obtain higher weight efficiencies, which are especially important for space and automotive applications. The complete system includes a hydrogen storage tank based on Ti-doped sodium alanate and a novel oxygen tank based on YBaCo4O7 developed at ARC. Water tanks and a micro-fluidic system connected to the fuel cell have been considered as well in order to provide a completely reversible system, competitive to batteries. For the hydrogen storage, a finite elements model has been developed, implementing the reaction kinetics of the storage process, in order to predict the thermal mechanisms during adsorption and desorption of hydrogen in sodium alanate. The present paper discusses these simulations, the development of an experimental hydrogen storage tank and the proposed concepts of a battery replacement system.
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    Development of Innovative Hydrogen and Micro Energy Solutions at the Austrian Research Centers
    (American Institute of Aeronautics and Astronautics, 2008-07-28)
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    Tajmar, Martin 
    ;
    Dudzinski, Piotr 
    ;
    Reissner, Alexander 
    Scopus© Citations 5  202  274
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    Micro-Propulsion and Power Developments at AIT
    (2009-01-12)
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    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.
      2  147
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      148  209
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    Innovative Hydrogen Storage in Hollow Glass-Microspheres
    (2009)
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    Schmid, G. 
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    Tajmar, Martin 
      1  136
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    Verfahren und Anlage zum Speichern und Freisetzen von Wasserstoff
    (Espacenet, 2008-10-16)
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    Tajmar, Martin 
      204  247
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    Improved µ-scale Turbine Expander for Energy Recovery
    (ASME, 2010-06-14)
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    Dudzinski, Piotr 
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    Reissner, Alexander 
    ;
    Hummel, Stefan 
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    Tajmar, Martin 
    Scopus© Citations 4  166  350