All 10 research fellows in the Heat4Energy project have successfully been recruited and enrolled in their host institutions. Three schools on magnetic energy harvesting, thermomagnetic generator devices, experimental methods and modelling techniques were organized in Dresden (October 2024), Grenoble (May 2025) and Delft (November 2025). These schools included a soft skills program covering sustainability, entrepreneurship and science communication. A fruitful exchange of ideas between the industrial partners and the research groups was facilitated during the international DDMC’2025 workshop in Delft.
Computational design studies and thin-film combinatorial libraries have been completed, leading to promising material candidates. Early prototypes for thermomagnetic generators show encouraging conversion efficiency. Concerning the model-based engineering at different power ranges (i) small scale (μW): a simulation procedure for the design of mechanically coupled individual TMGs is currently under development, (ii) medium scale (W): a coupled model of the TMG was developed and validated, (iii) large scale (kW): a first of its kind 3D, coupled numerical model for the high-frequency regenerative thermomagnetic regenerator was developed. The fabrication technology is currently being advanced for all prototypes.
Achievements in the field of materials preparation include the successful synthesis of Heusler compounds in bulk form, as ribbons, and as thin films. Further, both bulk (Mn,Fe)2(P,Si) and (Mn,Cr)2Sb compounds with optimized properties for heat conversion applications were prepared. Shaping of the thermomagnetic materials into 3D printed structures has been advanced by the industrial partner Magneto. Thermomagnetic heat exchangers with filament resolution down to 250 μm have been printed in varying sizes with mostly cuboidal geometry. By adjusting the printing and sintering parameters, the porosity and hydraulic diameter can be adjusted. In the field of functional characterization of thermomagnetic materials, the chemical composition of Heuslers was studied and optimized to ensure stability within the operational temperature range (300 – 400 K). The physical properties have been thoroughly characterized and in-operando tests using a Curie wheel are currently in progress. Characterization of the field-induced ferromagnetic transition in (Fe,Mn)2(P,Si) was investigated by advanced synchrotron X-ray diffraction measurements to provide direct insight in the internal transformation strains that develop when the ferromagnetic to paramagnetic transition. Understanding of the development of internal strains and stresses is of critical importance for the materials lifetime during cycling for heat conversion applications.
A meso-scale simulation architecture has been developed that bridges length scales and offers insights into the interdependence of magnetic, mechanical and thermal effects on the properties and performance of thermomagnetic materials. So far, key advances include a coupled thermal-mechanical model that computes phase transformation induced stresses and the elastic energy density in a polycrystalline sample. This model is informed by the mechanical properties for magnetocaloric Mn(Ni,Ga)2 materials. Using this model, the effect of grain size, orientation, grain morphology and the presence and density of voids on resulting stress fields was investigated. First-principles feasibility studies were carried out for some archetypal magnetocaloric systems. This resulted in a list of screening criteria. The initial screening with these criteria resulted in a materials shortlist. This shortlist will be updated continuously.
Simulation models for upscaling have been completed, and preliminary designs for a medium-scale demonstrator are under review. Industrial partners have been engaged to support feasibility studies and TRL advancement. Current prototypes show encouraging conversion efficiencies. The next steps include finalizing the demonstrators and validating performance metrics. The industrial partners are actively engaged in prototype development. The exchange of ideas between the research fellows and the industrial partners is stimulated via company secondments.
