Linear Thermomagnetic Energy Harvester for Low-Grade Thermal Energy Harvesting

Ravi Kishore, Deepa Singh, Rammohan Sriramdas, Anthony Garcia, Mohan Sanghadasa, Shashank Priya

Research output: Contribution to journalArticlepeer-review

25 Scopus Citations

Abstract

Low-grade thermal energy, either from waste heat or from natural resources, constitutes an enormous energy reserve that remains to be fully harvested. Harvesting low-grade heat is challenging because of the low Carnot efficiency. Among various thermal energy harvesting mechanisms available for capturing low-grade heat (temperature less than 100 °C), the thermomagnetic effect has been found to be quite promising. In this study, we demonstrate a scalable thermomagnetic energy harvester architecture that exhibits 140% higher power density compared to the previously published spring-mass designs. The alternating force required to oscillate the thermomagnetic mass is generated through the interaction between two magnetic forces in opposite directions. We employed numerical modeling to illustrate the behavior of a thermomagnetic device under different operating conditions and to obtain the optimal hot-side and cold-side temperatures for continuous mode operations. A miniaturized thermomagnetic harvester was fabricated and experiments were conducted to systematically evaluate the performance. The prototype was found to exhibit an oscillation frequency of 0.33 Hz, a work output of 0.6 J/kg/cycle, and a power density of 0.2 W/kg of gadolinium under the temperature difference of 60 K.

Original languageAmerican English
Article number044501
Number of pages14
JournalJournal of Applied Physics
Volume127
Issue number4
DOIs
StatePublished - 31 Jan 2020

Bibliographical note

Publisher Copyright:
© 2020 Author(s).

NREL Publication Number

  • NREL/JA-5500-76025

Keywords

  • electromagnetism
  • energy harvester
  • ferromagnetic materials
  • magnetic fields
  • magnetic materials
  • mechanical energy
  • numerical methods
  • phase transitions
  • thermoelectricity
  • thermomagnetic effects

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