Experimental comparison of multi-layered La–Fe–Co–Si and single-layered Gd active magnetic regenerators for use in a room-temperature magnetic refrigerator

We present experimental comparison of different parallel-plate active magnetic regenerators (AMRs) with two different groups of magnetocaloric materials. First, a gadolinium-based single-layered AMR was tested and analysed under different operating conditions. In the next step, three different multi-layered AMRs with different compositions and different Curie temperatures made from LaFe13 − x − yCoxSiy materials were constructed and tested. Seven-, four- and two-layered La-based AMRs were evaluated. The measurements were performed with respect to the maximum measured temperature span under different operating conditions and the cooling load under different temperature spans. In order to find the optimum operating temperature range the AMRs were further compared for different hot-side temperatures. The Gd-based AMR produced a larger temperature span, especially at higher operating frequencies and higher mass-flow rates. Among the multi-layered La–Fe–Co–Si AMRs, the seven- and four-layered AMRs showed very similar characteristics, while the two-layered AMR was much poorer.