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Title Magnetisk køling
Author Christensen, Dennis (Fuel Cells and Solid State Chemistry Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Bachelor thesis
Year 2009
Abstract Magnetic refrigeration provides an environmentally friendly and energy efficient alternative to conventional refrigeration. Magnetic refrigeration is based on the magnetocaloric effect, which manifests itself as an adiabatic temperature change upon application of an external magnetic field. The magnetocaloric effect depends on the magnetic properties of the magnetocaloric material used. A characterization of the magnetization and internal magnetic field are presented here for 3 types of materials with an orthorhombic shape. The first material has a uniform magnetization, which is independent of the external field. In this case the internal magnetic field can be solved analytically. The second and third material is a linear and ferromagnetic material respectively. Generally, solving for the magnetic field and magnetization inside these materials requires numerically calculations. Therefore, a model capable of predicting these quantities is developed. The model uses the mean field theory to describe the ferromagnetic material as the benchmark material in magnetic refrigeration (gadolinium) generally is well described by this theory. Further, the adiabatic temperature change in gadolinium is measured with an infrared camera. By comparing the results of the measurement with the model, one is able to predict the qualitative features of the temperature change. At the present stage the quantitative description is subjected to considerable deviations.
Imprint Københavns Universitet : København
Pages 41
Keywords Brændselsceller og brint; Fuel Cells and Hydrogen; Magnetisk køling; Magnetic refrigeration
Fulltext
Original PDF DennisChristensenBachelorProject.pdf (3.62 MB)
Admin Creation date: 2010-12-14    Update date: 2010-12-14    Source: dtu    ID: 271337    Original MXD