Browsing by Author "Tomczyk, Piotr Aleksander"

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Kształtowanie właściwości fizykochemicznych adsorbentów węglowych dla układów magazynowania energii
(Data obrony: 2008) Wolak, Eliza
Wydział Paliw i Energii
Processes of mass and energy storage with the application of solid adsorbents can be included into prospective directions of the adsorption technology development. One of the aim of this study was to assessment and development of the properties of adsorbents preparing from carbon and vegetable precursors used for adsorption refrigeration systems. Another aim was design original apparatus measuring the heat of wetting of methanol, which makes possible to assess the thermal effects of adsorption without necessity of evaluation of isosteric heat of adsorption from adsorption isotherm. In doctoral thesis were proved the improvement of sorption properties and the nature of carbon adsorbent surface for different precursors on the way of consequently of shape change and geometric dimensions particles, chemical treatment (demineralization, oxidation) and activation with KOH,. Heat exchange between adsorbent and environment can be optimized when the packing of particles of adsorbent in the bed increase or carbon monoliths, which have an elevated thermal conductivity on the interfacial surface, are used. The proposed and designed method of measuring of the wetting heat makes possible to evaluate the thermal effects of methanol adsorption for the investigated carbon adsorbents.
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Numeryczna analiza pola gęstości prądu i temperatury w ogniwie paliwowym
(Data obrony: 2005) Schmidt, Paweł
Wydział Elektrotechniki, Automatyki, Informatyki i Elektroniki
In the last years fuel cells have found the wide range of application as alternative power sources. Their popularity due to lowering costs of the energy production and arising costs of mining and utilization of the traditional fuels such as coal or oil. The influence on the lowering costs of the production and utilization of the fuel cell systems has applying the better and cheaper materials used to the production of the fuel cells and optimisation of the operational parameters of fuel cell systems. The optimisation was possible by applying numerical simulations and modelling the processes, which take place in the entire of the fuel cell and also in the external components of the fuel cell systems. The main goal of this work is to prove the possibility of the numerical modelling of the current density and temperature fields in the whole fuel cell. Because these phenomena are closely related to the electrochemical reactions which occurring at the boundary between electrodes and electrolyte of the cell, they cannot be modelled without the analysis of the reactants flow in the electrodes-electrolyte assembly. For this reason the additional goal of this work to develop the models of the mass transport in the fuel cell. The models give the possibility of the further investigations of the fuel cells phenomena. On the basis of the mass transport laws the numerical models described by the non-linear partial differential equations were developed. These models give the possibility to calculate the reactants flow in the individual parts of the fuel cell. On this base the extended numerical models, which enable calculations of electrical and temperature fields, were developed. The lots of aspects of the fuel cell operation such as timedomain analysis or effects of material parameters on fuel cell performance were also investigated. To the each of these numerical models the computational example is atattached. The examples illustrate the essence of the phenomenon, which take place in the entire of the fuel cell. The systems of non-linear partial differential equations describing the models were solved using finite element method.