Influence of Layering and Curie Temperature Uncertainty on the Performance of Magnetocaloric Regenerators

In the paper Influence of Layering and Curie Temperature Uncertainty on the Performance of Magnetocaloric Regenerators, published in Advanced Functional Materials (IF = 19.0), researchers from the Laboratory for Refrigeration and District Energy (Faculty of Mechanical Engineering, University of Ljubljana) investigate how statistical variations in Curie temperature affect the performance of multilayer active magnetic regenerators (AMRs). We conducted the research in collaboration with colleagues from the University of Santa Catarina (Brazil) and the Technical University of Denmark.

Magnetic refrigeration is a promising alternative to vapor-compression cooling, offering better energy efficiency and lower environmental impact. However, the narrow operational temperature window of magnetocaloric materials (MCMs) and the use of rare-earth elements are major limitations. Layering several MCMs with different Curie temperatures can help span broader temperature ranges—but introduces sensitivity to material variability.

Using a 1D numerical model and radial basis function neural networks, the team analyzed how Curie temperature uncertainties affect the cooling power of multilayer AMRs made from La-Fe-Co-Si alloys. Results reveal that while more layers improve peak performance, they also increase sensitivity to manufacturing inconsistencies. Even standard deviations above 1 K can significantly reduce the probability of reaching desired cooling targets.

This work underscores the need for precise control over MCM properties and contributes essential insights into designing robust and commercially viable magnetocaloric systems.

Figure: Probability of all the Curie temperatures being distributed such that the normalized cooling power would be equal to or greater than 0.9 relative to the standard deviation and at three different temperature spans for different numbers of MCM layers.