Multi-physics model of a thermo-magnetic energy harvester

Keyur B. Joshi, Shashank Priya

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Harvesting small thermal gradients effectively to generate electricity still remains a challenge. Ujihara et al (2007 Appl. Phys. Lett. 91 093508) have recently proposed a thermo-magnetic energy harvester that incorporates a combination of hard and soft magnets on a vibrating beam structure and two opposing heat transfer surfaces. This design has many advantages and could present an optimum solution to harvest energy in low temperature gradient conditions. In this paper, we describe a multi-physics numerical model for this harvester configuration that incorporates all the relevant parameters, including heat transfer, magnetic force, beam vibration, contact surface and piezoelectricity. The model was used to simulate the complete transient behavior of the system. Results are presented for the evolution of the magnetic force, changes in the internal temperature of the soft magnet (gadolinium (Gd)), thermal contact conductance, contact pressure and heat transfer over a complete cycle. Variation of the vibration frequency with contact stiffness and gap distance was also modeled. Limit cycle behavior and its bifurcations are illustrated as a function of device parameters. The model was extended to include a piezoelectric energy harvesting mechanism and, using a piezoelectric bimorph as spring material, a maximum power of 318 μW was predicted across a 100 kΩ external load.

Original languageEnglish (US)
Article number055005
JournalSmart Materials and Structures
Volume22
Issue number5
DOIs
StatePublished - May 1 2013

Fingerprint

Harvesters
Physics
heat transfer
Heat transfer
Thermal gradients
physics
Magnets
magnets
vibration
cycles
piezoelectricity
Piezoelectricity
Energy harvesting
Gadolinium
gadolinium
electricity
energy
Numerical models
electric contacts
stiffness

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering

Cite this

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Multi-physics model of a thermo-magnetic energy harvester. / Joshi, Keyur B.; Priya, Shashank.

In: Smart Materials and Structures, Vol. 22, No. 5, 055005, 01.05.2013.

Research output: Contribution to journalArticle

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