A novel miniature thermomagnetic energy harvester

Chin Chung Chen, Tien-Kan Chung, Chi Cheng Cheng, Chia Yuan Tseng

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations

Abstract

Nowadays, thermal-energy-harvesting is an important research topic for powering wireless sensors. Among numerous thermal-energy-harvesting approaches, some researchers demonstrated novel thermomagnetic-energy harvesters to convert a thermal-energy from an ambient temperature-difference to an electrical-output to power the sensors. However, the harvesters are too bulky to be integrated with the sensors embedded in tiny mechanical-structures for some structuralhealth- monitoring applications. Therefore, miniaturized harvesters are needed. Hence, we demonstrate a miniature thermomagnetic-energy harvester. The harvester consists of CuBe-beams, PZT-piezoelectric-sheet, Gd-soft-magnet, NdFeB-hard-magnet, and mechanical-frame. The piezoelectric-sheet and soft-magnet is bounded at fixed-end and freeend of the beams, respectively. The mechanical-frame assembles the beams and hard-magnet. The length× width×thickness of the harvester is 2.5cm×1.7cm×1.5cm. According to this, our harvester is 20-times smaller than the other harvesters. In the initial-state of the energy-harvesting, the beams' free-end is near the cold-side. Thus, the soft-magnet is cooled lower than its curie temperature (Tc) and consequently changed from paramagnetic to ferromagnetic. Therefore, a magnetic-attractive force is produced between the soft-magnet and hard-magnet. Consequently, the beams/soft-magnet are down-pulled toward the hard-magnet fixed on the hot-side. The soft-magnet closing to the hot-side is heated higher than its Tc and subsequently changed to paramagnetic. Consequently, the magnetic-force is eliminated thus the beams are rebounded to the initial-state. Hence, when the harvester is under a temperature-difference, the beams' pulling-down/back process is cyclic. Due to the piezoelectric effect, the piezoelectric-sheet fixed on the beams continuously produces voltage-response. Under the temperature-difference of 29°C, the voltage-response of the harvester is 30.4 mV with an oscillating-frequency of 0.098 Hz.

Original languageEnglish
Title of host publicationActive and Passive Smart Structures and Integrated Systems 2014
PublisherSPIE
ISBN (Print)9780819499837
DOIs
StatePublished - 1 Jan 2014
EventActive and Passive Smart Structures and Integrated Systems 2014 - San Diego, CA, United States
Duration: 10 Mar 201413 Mar 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9057
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceActive and Passive Smart Structures and Integrated Systems 2014
CountryUnited States
CitySan Diego, CA
Period10/03/1413/03/14

Keywords

  • Energy Harvester
  • Magnetic
  • Piezoelectric
  • Power Generator
  • Thermal

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    Chen, C. C., Chung, T-K., Cheng, C. C., & Tseng, C. Y. (2014). A novel miniature thermomagnetic energy harvester. In Active and Passive Smart Structures and Integrated Systems 2014 [90570X] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9057). SPIE. https://doi.org/10.1117/12.2045294