Turning the concept of magnetocaloric cooling on its head

Exploit the hysteresis, not avoid

Smart design of materials

Computing power

Advanced laboratory equipment

Welcome to COOL INNOV

The outstanding research at the Functional Materials group of TU Darmstadt for the substitution of critical raw materials and materials for energy technologies has been recognized by honoring Prof. Dr. Oliver Gutfleisch with ERC Advanced Grant COOL INNOV.

COOL INNOV will attempt to achieve a breakthrough in caloric cooling based on magnetocaloric materials by rethinking the whole concept of this technology. Instead of the conventional idea of squeezing the best out of magnetostructural phase-change materials in relatively low magnetic fields, a second stimulus introduced in the form of pressure can help the COOL INNOV team to exploit, rather than avoid, the hysteresis that is inherent in these materials. It should lead to more efficient refrigeration, with a commercially viable technology that could satisfy the urgent global need.

COOL INNOV received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant no. 743116 - project Cool Innov).

COOL INNOV Research

Safe and efficient magnetic refrigeration
 
Safe and efficient magnetic refrigeration
Environmentally friendly and energy efficient alternative to the conventional cooling based on the magnetocaloric effect, taken one step further
Team
 
Team
The Cool Innov team consists of experienced scientists and young talented students working in experimental and theoretical physics
First principle calculations
 
First principle calculations
DFT-based high-throughput search for new compounds combined with detailed phase transitions calculations
Finite element method simulations
 
Finite element method simulations
FEM simulations including micromagnetics for calculating the magnetic properties and behavior of new magnetocaloric materials
Publications
 
Publications
Articles published in the framework of the project and other articles on the topic of multi-calorics and related physics
Additive manufacturing
 
Additive manufacturing
Implementing 3D printing for engineering heat exchangers with complex structures from magnetocaloric materials
Development of new materials
 
Development of new materials
Synthesis and modification using advanced processing routes of mechanically stable materials with the large magnetocaloric effect
Multi-stimuli concept
 
Multi-stimuli concept
Utilization of magnetic field and uniaxial mechanical stress for enhancing the efficiency of magnetocaloric devices
Devices and equipment
 
Devices and equipment
Modern techniques and versatile devices are available to characterise the magnetic and mechanical properties of new materials

Latest work

Influence of microstructure on the application of Ni-Mn-In Heusler compounds for multicaloric cooling using magnetic field and uniaxial stress

Ni-Mn-based Heusler compounds alloys exhibit outstanding caloric effects in the vicinity of martensitic transformations driven by magnetic fields, uniaxial stress or hydrostatic pressure. However, the application in cooling devices is limited by energy losses and/or irreversibilities during cyclic operation as a result of their large inherent thermal hysteresis. An auspicious approach to enahance the cyclic caloric effect is the simultaneous or sequential combination of magnetic fields and uniaxial stress in multicaloric cooling concepts. In this work, we have chosen Ni-Mn-In as a model system to study the impact of microstructure on multicaloric cooling. We reveal a crucial role of grain orientation on the stress-induced martensitic transformation as well as the impact of grain size on the mechanical stability and the magnetic-field-induced transformation dynamics. Moreover, we demonstrate that a tailored microstructure can enable siginificant multicaloric effects which largely outperform their single-caloric counterparts. Thus, a reversible caloric effect of -4.1 K could be achieved in a multicaloric “exploiting-hysteresis cycle” by the sequential combination of a magnetic field of 1.9 T and a moderate stress of 55 MPa. This corresponds to an increase of more than 200 % compared to the reversible magnetocaloric effect for similar field changes. We thank our collaborators from the Universitat de Barcelona and the Helmholtz-Zentrum Dresden-Rossendorf.

The article Influence of microstructure on the application of Ni-Mn-In Heusler compounds for multicaloric cooling using magnetic field and uniaxial stress by L. Pfeuffer, A. Gràcia-Condal, T. Gottschall, D. Koch, T. Faske, E. Bruder, J. Lemke, A. Taubel, S. Ener, F. Scheibel, K. Durst, K. P. Skokov, L. Mañosa, A. Planes, and O. Gutfleisch is published in Acta Materialia 217, 117157 (2021). See more of our activity in News
Giant caloric effects based on the combination of magnetic field and uniaxial stress

The increasing demand for artificial cold and the ever-growing importance of climate protection call for new energy-efficient and environmentally-friendly alternatives to the conventionally used vapor-compression technology. The most promising candidate is solid-state caloric cooling which is based on the thermal response of a material to an external stimulus such as magnetic field, electric field, uniaxial stress or hydrostatic pressure. In our joint work with researchers from Helmholtz-Zentrum Dresden-Rossendorf and Universidad de Barcelona we demonstrate that the combination of more than one external stimulus can largely outperform the single caloric response. In particular, we show for the metamagnetic shape-memory alloy Ni-Mn-In a doubling of the caloric effect by the combined action of magnetic field and uniaxial stress compared to the corresponding single magneto- and elastocaloric one. Read more

The article Multicaloric effects in Metamagnetic Heusler Ni-Mn-In under uniaxial stress and magnetic field by A.Gràcia-Condal, T. Gottschall, L. Pfeuffer, O. Gutfleisch, A. Planes, and L. Mañosa is published in Applied Physics Reviews 7, 041406 (2020). See more of our activity in News