The lecture describes an overview of the development of the magnetic refrigeration technology at the Faculty of Mechanical Engineering (University of Ljubljana) in the last six years (2006-2012). The short review and the basics of the magnetic refrigeration technology are described in the introduction of the lecture. The second part of the lecture presents the development of the prototype of the rotary magnetic refrigerator developed at the Faculty of Mechanical Engineering. The basic operational principle and the analysis of the magnet assembly of the prototype are shown, and furthermore, some constructional problems which enable efficient operation are described as well. In the third part of the paper the developed and built experimental device for the analysis of the active magnetic regenerator (AMR), as the key element of the magnetic refrigerator, is presented. It has been shown that the geometry of the AMR has a crucial impact on the operation of the magnetic refrigerator. The innovative technology for the construction of the AMR based on the laser welding is presented and described as well. The final part of the lecture presents the future work in the field of magnetic refrigeration, which includes the alternative solution for a faster heat transfer in the AMR by using thermal diodes.
B.04 Guest lecture
COBISS.SI-ID: 12032539The present invention relates to the manufacturing process of the active magnetic regenerator of magnetocaloric materials using laser-welding technology. At first at least one spacer is produced on the magnetocaloric plate, after which a series of plates of magnetocaloric material, designed with at least one spacer, is put on each other in order to create a fund. The fund of a series of plates of magnetocaloric material, designed with at least one spacer, is then connected into said regenerator.
F.33 Slovenian patent
COBISS.SI-ID: 12596507Most of the existing prototype devices in magnetic refrigeration are based on the active magnetic regenerative cycle (AMR), which operates as a Brayton, regenerative magnetic refrigeration cycle. However, there exist several other potential cycles, that may not influence only the efficiency, but also the cost, compactness, or simplicity of magnetocaloric devices. The article presents results of the numerical analyses, and compares characteristics of different thermodynamic cycles, under different operating conditions. Discussion on the possibility of the introduction of new potential thermodynamic cycles is given in the article. This is supported by the brief information and comparison of corresponding magnetic field sources. Important guidelines for the future work on new magnetic thermodynamic cycles are given in the paper.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 12462363On the basis of international cooperation and achievements in the field of magnetic refrigeration International Institute of Refrigeration (IIRIIF) has entrusted us to the co-organize the Third International Conference on Magnetic Refrigeration at Room Temperature (Thermag III), held between 11 and 15 May, 2009 at IOWA State University in Des Moines, USA. In the Thermag III Conference prof. Poredoš and assist. prof. Kitanovski was also the co-editor of the proceedings.
C.01 Editorial board of a foreign/international collection of papers/book
COBISS.SI-ID: 11049499A new AMR experimental device has been designed, built and successfully tested. Its operation is based on the linear movement of the permanent magnet assembly over the static AMR. Two pistons serve for the counter fluid flow operation. The magnet assembly provides a magnetic field of 1.15 T (measured). Experiments have been performed for different kinds of regenerators at different operation conditions (mass flow rate and operation frequency) in order to obtain maximum temperature span (at zero load conditions) and cooling capacity at different temperature spans. In this paper, the results are presented for the AMR consisted of gadolinium (Gd) plates and voids with thickness of 0.25 mm. Maximum temperature span of 16 K was measured and 7 W of the cooling capacity was measured at 1 K of the temperature span. The second part of the paper regards the comparison between experimental and numerical results (of the previously developed numerical model).
B.03 Paper at an international scientific conference
COBISS.SI-ID: 12461851