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1

The Concept of a Novel Cold Storage Device Utilizing the Magnetocaloric Effect

Katana Katarzyna, Grzebielec Andrzej

Modern Engineering

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2023

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nr 4

38--49

EN

Cold storage poses many more problems than heat storage. This is due to the fact that the temperature range is smaller than in the case of heat storage facilities. The simplest example is that cold water chillers operate in the temperature range of 12/7 C and the heating system operates in the temperature range of 90/70 C. This means that at the start the volume in sensible heat is almost three times greater. For this reason, cold is rarely stored in the form of sensible heat. Phase change solutions (PCM) or physical reactions (adsorption) or chemical reactions (absorption) are much more frequently used. A completely different idea for improving the operation of cold stores is the use of magnetocaloric materials. These are materials that change temperature under the influence of a magnetic field. The article presents the concept of a cold store that cooperates with a heat exchanger made of magnetocaloric materials (pure Gadolinium). As a result of the preliminary analysis, it was determined that this combination of vapour compressor system and magnetocaloric heat exchanger allows for a reduction in energy consumption for storage purposes at the level of 58,6% in comparison to regular vapour compressor system.

2

Structural and magnetic studies of the Fe-B-Cr-Gd alloy provided for heat pump

Kotynia K.

Hutnik, Wiadomości Hutnicze

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2016

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Vol. 83, nr 6

275--277

EN

In the paper the rsults of studies of magnetocaloric effect in Fe-B-Cr-Gd amorphous alloy are presented. Fe-B-Cr-Gd glassy alloys seem to be promising candidates as active elements in magnetic heat pump due to the fact that they demonstrate relatively large magnetic entropy change ΔSM above room temperature. The studied samples were obtained by melt-spinning technique. Structural analysis was performed using X-ray diffractometry and Mössbauer spectroscopy. Temperature dependence of magnetization was measured using PPMS system at constant low magnetic field (H = 0.01 T).

PL

W artykule przedstawiono wyniki badań efektu magnetokalorycznego w stopie amorficznym Fe-B-Cr-Gd. Stop Fe-B-Cr-Gd jest obiecujący, pod względem aplikacji jako aktywny element magnetycznej pompy ciepła ze względu na fakt, że ujawniają one stosunkowo duże zmiany entropii magnetycznej ΔSM powyżej temperatury pokojowej. Zbadane próbki otrzymano techniką melt – spinning. Analiza strukturalan została przeprowadzona przy użyciu dyfrakcji rentgenowskiej oraz spektroskopii mössbauerowskiej. Zależność temperatury od namagnesowania została zmierzona za pomocą systemu PPMS w stałym polu magnetycznym (H = 0,01 T).

3

Ekologiczne chłodziarki magnetyczne

Sulima R.

Prace Instytutu Elektrotechniki

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2013

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Z. 261

117--128

PL

Artykuł opisuje cykl przemiany energii w materiałach magnetokalorycznych, prototypy wybranych konstrukcji układów chłodzących, ich wady i zalety. Przedstawiono również tło polityczne i warunki środowiskowe wymagane przez UE w stosunku do urządzeń chłodniczych i klimatyzacyjnych.

EN

The magnetocaloric effect (MCE) is a thermodynamic process in which the temperature changes of a paramagnetic material are the effect of an external magnetic field changing in cycles. The refrigeration occurs in two stages: the first one is the isothermal magnetizing of the material, during which the intensity of the magnetic field rises from H0 to H3 (Fig. 1 process 1-2); during the magnetizing the dipoles of the paramagnetic material become arranged parallely to the intensity of the external magnetic field and the entropy of the material decreases from S1 to S2. As a result of magnetizing, heat is transferred to the surroundings in a quantity proportional to the work executed by the magnetic field. The second stage is the adiabatic demagnetization of the paramagnetic material to the value of the field intensity of H0, during which there occures a decrease in temperature of the material from Tp to T12 (Fig. 2 process 2-3).

4

Phase constitution of an LaFe11.0Co0.8(Si0.4Al0.6)1.2 alloy investigated by Mössbauer spectroscopy

Gębara P., Pawlik P., Wysłocki J. J., Szwaja M.

Nukleonika

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2013

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Vol. 58, No. 1

113-116

EN

In the present work the phase constitution and magnetic ordering of the magnetocaloric LaFe11.0Co0.8(Si0.4Al0.6)1.2 alloy in the as-cast state and after annealing at 1323 K for 1 h (in case of ribbons) and 49 days (in case of bulk) were studied. For bulk and ribbon samples in as-cast state three crystalline phases were identified: dominant ferromagnetic alfa-Fe, minor ferromagnetic La(Fe,Co)Si and traces of paramagnetic La(Fe,Si)13 phase. Appropriate heat treatment resulted in the evolution of phase constitution of the alloy, where two crystalline phases were developed: the dominant paramagnetic La(Fe,Si)13 phase and a minor fraction of the ferromagnetic alfa-Fe for both bulk and ribbon samples.

5

The evolution of microstructure in annealed LaFeSi-type alloys

Gębara P., Pawlik P., Wysłocki J. J., Kulej E., Pawlik K., Przybył A.

Optica Applicata

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2009

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Vol. 39, nr 4

761-764

EN

The evolution of microstructure and the phase constitution of the LaFe11.0Co0.8(Si0.4Al0.6)1.2 alloy in as-cast state and after subsequent annealing at 1323 K for 10, 20, 49 days was studied. In the LaFe11.0Co0.8(Si0.4 Al0.6)1.2 alloy after arc-melting, the dominant dendritic ?-Fe phase crystallizes, which is confirmed by X-ray diffraction. Annealing of the samples resulted in evolution of microstructure and the phase constitution. Prolonged annealing of the samples causes almost full homogenization of the alloy with the single-phase structure identified as La(Fe0.85Co0.06Si0.04Al0.05)13 phase of the NaZn13-type structure.