Magnetic refrigeration: an eco-friendly technology for the refrigeration at room temperature

33rd UIT (Italian Union of Thermo-fluid dynamics) Heat Transfer Conference

物理学;力学

Aprea, C.^1 ; Greco, A.^2 ; Maiorino, A.^1 ; Masselli, C.^1

DII, Universitá di Salerno, via Giovanni Paolo II 132, Fisciano, Salerno

84084, Italy^1

DII, Universitá Degli Studi di Napoli Federico II, P.le Tecchio 80, Napoli

80125, Italy^2

关键词: Eco-friendly technologies;    Environment friendly technology;    First-order magnetic transition;    Magnetic refrigerators;    Magnetocaloric materials;    Second-order magnetic transitions;    Total equivalent warming impacts;    Vapor compression plant;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/655/1/012026/pdf
DOI  :  10.1088/1742-6596/655/1/012026

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials MCE is a warming as the magnetic moments of the atom are aligned by the application of a magnetic field, and the corresponding cooling upon removal of the magnetic field. There are two types of magnetic phase changes that may occur at the Curie point: first order magnetic transition (FOMT) and second order magnetic transition (SOMT). The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative cycle) where the magnetic material matrix works both as a refrigerating medium and as a heat regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating fashion through the regenerator made of magnetocaloric material that is alternately magnetized and demagnetized. In this paper, attention is directed towards the near room-temperature range. We compare the energetic performance of a commercial R134a refrigeration plant to that of a magnetic refrigerator working with an AMR cycle. Attention is devoted to the evaluation of the environmental impact in terms of a greenhouse effect. The comparison is performed in term of TEWI index (Total Equivalent Warming Impact) that takes into account both direct and indirect contributions to global warming. In this paper the AMR cycle works with different magnetic refrigerants: pure gadolinium, second order phase magnetic transition (Pr0.45Sr0.35MnO3) and first order phase magnetic transition alloys (Gd5Si2Ge2, LaFe11.384Mn0.356Si1.26H1.52, LaFe1105Co0.94Si110and MnFeP0.45As0.55). The comparison, carried out by means of a mathematical model, clearly shows that GdSi2Ge2and LaFe11.384Mn0.356Si1.26H1.52has a TEWI index always lower than that of a vapor compression plant. Furthermore, the TEWI of the AMR cycle working with FOMT materials is always better than that of SOMT materials. Gd5Si2Ge2is the best FOMT material.