Experimental study of non-bonded packed bed active magnetic regenerators with stabilized La(Fe,Mn,Si)13Hy particles

Jierong Liang,Kurt Engelbrecht,Alexander Barcza,Christian R.H Bahl,Hugo A Vieyra,Marvin Masche,Kaspar K Nielsen

doi:10.1016/j.applthermaleng.2021.117383

Jierong Liang, Kurt Engelbrecht + Show 5 more

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https://doi.org/10.1016/j.applthermaleng.2021.117383

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Abstract

• Non-bonded regenerator with first order particles was successfully tested for one year. • Non-bonded regenerators can stably improve cooling performance. • The material is stabilized without causing significant performance degradation. • Reduced flow resistance in non-bonded regenerators yields lower friction factors. The aim of this study is to develop more stable magnetocaloric regenerators, made from non-epoxy-bonded La(Fe,Mn,Si) 13 H y particles to address the instability issues of conventional regenerators with a first-order phase transition. The stabilized magnetocaloric materials are obtained by increasing the α − Fe content at the expense of a small reduction of the adiabatic temperature change. However, the experimental results show that the non-bonded structure improves the regenerator efficiency and reduces pressure drop, potentially compensating for the reduction of the material’s magnetocaloric effect. Compared to epoxy-bonded regenerators, non-bonded regenerators exhibit a larger temperature span (10.2 K at no load) and specific cooling power (27% improvement at a span of 4 K). Due to the elimination of the epoxy, a lower friction factor and higher packing density are obtained. The long-term mechanical and chemical stabilities are verified by comparing specific heat, effectiveness, and pressure drop before and after a test period of more than one year.

Highlights

Caloric technologies, being alternatives to vapor compression refrigeration at room temperature, have been widely studied in recent decades [1,2,3,4,5]
In addition to the thermal–hydraulic investigations [23,24,25,26], it is central for re searchers to focus on the stability and efficiency of magnetocaloric materials (MCMs) that are used in AMRs [27,28,29]
We repro duced AMRs Sph2-HS and Sph3-HS using the MCMs from Sph1-HS to investigate the effect of enhancing the packing quality

Summary

Introduction

Caloric technologies, being alternatives to vapor compression refrigeration at room temperature, have been widely studied in recent decades [1,2,3,4,5]. To realize the potential benefits of caloric cooling and heating, which includes the use of environmentally friendly refrigerants, high efficiency, and lower noise, the interdisciplinary knowledge related to material science [6,7,8,9], magnetic system design [10,11,12], and ther modynamics [13,14,15] is highly desired to develop high-performance prototypes [16,17,18,19,20]. As a pioneer caloric application, magnetocaloric refrigeration has been developed mostly based on the active magnetic regenerator (AMR, [21]). AMRs exhibit the magnetocaloric effect (MCE) by magnetocaloric materials (MCMs) and simultaneously enable heat regeneration along the length of the solid refrigerant [22]. In addition to the thermal–hydraulic investigations [23,24,25,26], it is central for re searchers to focus on the stability and efficiency of MCMs that are used in AMRs [27,28,29]

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