MnNiSi based magnetocaloric alloys for Cooling and energy harvesting applications
- Nov 13, 2019
- 10:30 AM - 11:30 AM
- Deepak Kamble
- School of Materials Science and Engineering, Nanyang Technological University, Singapore
- Main Topic
- Ines Firlle
- Magnetic cooling and energy harvesting technology relies on magnetocaloric materials. Current research focuses on MCMs are to develop rare-earth free, high performance, low cost, environmentally friendly and readily available materials. Substitutional alloying of MnNiSi can decrease the TC and induce a coupling of magnetic and structural transition. Single element substitution by Fe can reduce the TC upto 438 K. To further bring down the TC to near room temperature, double element substitution, e.g., by Fe and Ge, is required.
(MnNiSi)1-x(Fe2Ge)x alloys, synthesized by arc melting, exhibited a magnetostructural transition at temperatures ranging from 363 K to 218 K by varying x from 0.32 to 0.36, respectively resulted in a giant magnetocaloric response with ΔSmax = 57.6 Jkg-1K-1, for a ΔH of 5 T). Low cost, Ge-free MnNiSi based alloys, (Mn0.45Fe0.55)Ni(Si1-ySny) exhibited TC from 352 K to 255 K by varying the Sn content from y = 0.12 to y = 0.18 with ΔSmax = 8.6 Jkg-1K-1 (ΔH =5T).
Waste heat is an unavoidable and undesirable product of a huge number of industrially important processes. Cooling of such a heat load is of high interest. We developed a novel hybrid thermomagnetic oscillator (TMO) for cooling of the heat load as well as electricity harvesting. The TMO uses the thermomagnetic response of MnNiSi-Fe2Ge alloy. Voltage of up to 10 V/cycle and a current of 15 mA was generated by the mechanical oscillation of this alloy and a coupled permanent magnet through solenoid type Cu coils. The (MnNiSi)0.68(Fe2Ge)0.32 showed the highest figure of merit (Energy per cycle * Frequency), and was selected for a given heat load temperature to study the effect of spacer material on the performance. It was revealed that a flexible spacer can increase the oscillation frequency by 32% and the voltage/cycle by 18% compared to a rigid spacer.
Last modified: Nov 12, 2019, 12:10:09 AM
Leibniz Institut für Festkörper- und Werkstoffforschung Dresden (D2E.31, IFW Dresden)Helmholtzstraße2001069Dresden
Leibniz Institut für Festkörper- und Werkstoffforschung DresdenHelmholtzstraße2001069Dresden
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