Shape Memory Alloy Engine for High Efficiency Low-Temperature Gradient Thermal to Electrical Conversion

Ravi Kishore, Prashant Kumar, Deepam Maurya, Colin Stewart, Reza Mirzaeifar, Eckhard Quandt, Shashank Priya

Research output: Contribution to journalArticlepeer-review

23 Scopus Citations


More than half of the energy generated worldwide is lost as unused thermal energy because of the lack of efficient methodology for harnessing the low-grade heat. Here we demonstrate that shape-memory alloy can be an effective mechanism for recovering low-grade heat. Shape memory alloys exhibit thermally induced martensite to austenite phase transformation and super-elasticity (stress-induced martensitic transformation). Employing these two characteristics, we demonstrate a thermal engine for harnessing waste energy through all modes of heat transfer: convection, conduction, and radiation. In this work, we performed material and heat transfer analysis for achieving high frequency, sustainable and efficient operation of our engine. An optimized shape memory alloy engine generated 36 W per kilogram or 234 kW of electricity per cubic meter of active material. A continuous three-day operation of several SMA engines could generate 7.2 kWh of electricity when installed on a 500 m long hot pipe network. This generated power can potentially reduce the carbon footprint by 5.1 kg of CO2 illustrating the promise of this technology for addressing climate change.

Original languageAmerican English
Article number113277
Number of pages9
JournalApplied Energy
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© 2019 Elsevier Ltd

NREL Publication Number

  • NREL/JA-5500-75098


  • Austenite
  • Energy harvesting
  • Heat engine
  • Martensite
  • Pseudo-elasticity
  • Shape Memory Alloy (SMA)


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