Príspevok
Magnetocaloric cooling - a great alternative to compressor cooling at room temperature
DOI: 10.18462/iir.compr.2017.0280
Stav prijatia: Abstrakt odmietnutý
Autori
| Meno | Organizácia | |
|---|---|---|
| Róbert Tarasenko, RNDr., PhD, | Institute of Physics, Faculty of Science, P.J. Šafárik University in Košice | |
| Štefan Molokáč, Ing., CSc. | CRYOSOFT spol. s r.o., | |
| Alexander Feher, prof., RNDr., DrSc. | Institute of Physics, Faculty of Science, P.J. Šafárik University in Košice |
Abstrakt
In the twenty-first century, energy efficient and environmentally friendly technologies receive much attention to solve the energy crisis accompanied with a serious problem of a global warming phenomenon. In this context, refrigeration based on magnetocaloric effect (MCE) has attracted much research interest because of its higher energy efficiency in comparison with the conventional vapor compression refrigeration [1]. What is more, unlike conventional refrigerators, magnetic cooling does not use ozone-depleting greenhouse gases as refrigerants.
MCE resembles processes that occur in a gas in response to the changing pressure. Isothermal magnetizing of a refrigerant - magnetic material, reduces magnetic part of the entropy, ΔSM, and corresponds to isothermal compression of gas. Adiabatic demagnetizing (corresponding to adiabatic expansion of gas) is accompanied with an adiabatic temperature change, ΔTad. Both thermodynamic quantities describe the measure of MCE. Despite the fact that MCE is known for more than century [2], the first principle of magnetic refrigerator working near room temperature appeared only at the end of 20th century [3]. Another breakthrough was a discovery of a giant MCE in Gd5(Si2Ge2) near room temperature with -ΔSM ≈ 19 J/kg K, for field change 0 - 5 T [4]. The discoveries triggered flurry of research activities in a wide area of physics, chemistry and material science. The main aim of the actual research activities is to search for new materials with large MCE which can operate at different temperature ranges. Large MCE close to room temperature would be useful for household and several technological applications [1] while large MCE in low-temperature region can be utilized, e. g. in the process of liquefaction of helium for cryogenics, or hydrogen in fuel industry [5-6].
Our work has been supported by the projects APVV-14-0073, ERDF EU projects No. ITMS 26220120047 and ITMS 26220220186.
References:
[1] K. A. Gschneidner Jr., et al., Rep. Prog. Phys. 68 (2005) 1479.
[2] E. Warburg, Ann. Phys. 13 1881) 141.
[3] C. Zimm et al., Adv. Cryog. Eng. 43 (1998) 1759.
[4] V. K. Pecharsky et al., Phys. Rev. Lett. 78 (1997) 4494.
[5] A. Midya et al., Phys. Rev. B 84 (2011) 235127.
[6] V. Tkáč et al., Phys. Rev. B 92 (2015) 024406.
Kľúčové slová
magnetocaloric effect
magnetic cooling
energy efficiency