Harvesting electrical energy from torsional thermal actuation driven by natural convection

Shi Hyeong Kim, Hyeon Jun Sim, Jae Sang Hyeon, Dongseok Suh, Geoffrey M. Spinks, Ray H. Baughman, Seon Jeong Kim

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The development of practical, cost-effective systems for the conversion of low-grade waste heat to electrical energy is an important area of renewable energy research. We here demonstrate a thermal energy harvester that is driven by the small temperature fluctuations provided by natural convection. This harvester uses coiled yarn artificial muscles, comprising well-aligned shape memory polyurethane (SMPU) microfibers, to convert thermal energy to torsional mechanical energy, which is then electromagnetically converted to electrical energy. Temperature fluctuations in a yarn muscle, having a maximum hot-to-cold temperature difference of about 13 °C, were used to spin a magnetic rotor to a peak torsional rotation speed of 3,000 rpm. The electromagnetic energy generator converted the torsional energy to electrical energy, thereby producing an oscillating output voltage of up to 0.81 V and peak power of 4 W/kg, based on SMPU mass.

Original languageEnglish
Article number8712
JournalScientific Reports
Issue number1
StatePublished - 1 Dec 2018

Bibliographical note

Funding Information:
This work was supported by the Creative Research Initiative Center for Self-Powered Actuation of the National Research Foundation and the Ministry of Science, ICT & Future Planning (MSIP) in Korea. Support in Australia was from Centre of Excellence funding from the Australian Research Council. Support in the USA was from Air Force Grant AOARD-FA2386-13-4119, Air Force Office of Scientific Research grant FA9550-15-1-0089, and Robert A. Welch Foundation grant AT-0029.

Publisher Copyright:
© 2018 The Author(s).


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