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Caloric Effects in Ferroic Materials: New Concepts for Cooling
Author(s) -
Fähler Sebastian,
Rößler Ulrich K.,
Kastner Oliver,
Eckert Jürgen,
Eggeler Gunther,
Emmerich Heike,
Entel Peter,
Müller Stefan,
Quandt Eckhard,
Albe Karsten
Publication year - 2012
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201100178
Subject(s) - magnetic refrigeration , refrigeration , engineering physics , shape memory alloy , materials science , refrigerant , ferroelectricity , electrocaloric effect , mechanical engineering , caloric theory , phase transition , nanotechnology , condensed matter physics , magnetic field , magnetization , thermodynamics , engineering , physics , optoelectronics , heat exchanger , composite material , quantum mechanics , dielectric
Refrigeration is one of the main sinks of the German and European electricity consumption and accordingly contributes to worldwide CO 2 emissions. High reduction potentials are envisaged if caloric effects in solid materials are used. The recent discovery of giant entropy changes associated with ferroelastic phase transformations promises higher efficiency. Ferroic transitions enhance the entropy change of magneto‐, elasto‐, baro‐, and electro‐caloric effects. Furthermore, because the refrigerant is in a solid state, this technology completely eliminates the need for halofluorocarbon refrigerants having a high global‐warming potential. The smaller footprint for operation and the scalable mechanism open up further applications such as cooling of microsystems. While the principal feasibility of magnetocaloric refrigeration is already evident, it requires large magnetic fields (>2 T) which hampers wide industrial and commercial application. It is expected that this obstacle can be overcome by materials with lower hysteresis and by using stress‐ or electric fields. In order to accelerate research on ferroic cooling, the Deutsche Forschungsgemeinschaft (DFG) decided to establish the priority program SPP 1599 in April 2011. In this article we will address the major challenges for introducing ferroic materials in practical cooling applications: energy efficiency, effect size, and fatigue behavior. Solid state cooling in this sense can be based on the following “ferroic‐caloric” classes of materials: ferroelastic shape memory alloys, ferromagnetic shape memory alloys, and ferroelectric materials and their possible combinations in materials with “multicaloric” effects. The open questions require the interdisciplinary collaboration of material scientists, engineers, physicists, and mathematicians.