Annex VIII: Co-operative program on the development of thermoelectric materials for waste heat recovery in transportation industries

Annex Goals
The annex aims to develop test methods for the evaluation of thermoelectric materials and to develop precision statements for the standardization of these methods. Specifically, we aim to:

  • Exchange Technical information
  • Develop standard testing methods and procedures for thermoelectrics (power generation and heating/cooling)
  • Conduct international round-robin studies on thermoelectric materials (300-800 K)
  • Conduct international round-robin studies on thermoelectric devices (300-800 K)
  • Facilitate and promote the transition from materials R&D to commercial applications

Participating Countries and Laboratories

  • Oak Ridge National Laboratory, Oak Ridge, Tennessee (lead)
  • Marlow Industries, Dallas, Texas
  • General Motors R&D Center, Warren, Michigan
  • Army Research Laboratory, Adelphi, Maryland
  • Airforce Research Laboratory, Dayton, Ohio
  • Clemson University, Clemson, South Carolina
  • GMZ Energy, Waltham, Massachusetts
  • Gentherm (ZT-Plus), Los Angeles, California
  • Corning Inc. Corning, New York
  • National Institute of Standard and Technology (NIST), Gaithersburg, Maryland
  • University if Houston, Houston, Texas


  • CanmetMaterials, Hamilton Ontario (lead)
  • University of Waterloo, Waterloo, Ontario
  • Université du Québec à Chicoutimi, Chicoutimi, Quebec
  • Ecole Polytechnique de Montreal, Montreal, Quebec


  • Shanghai Institute of Ceramics, Chinese Academy of Sciences (CAS), Shanghai (lead)


  • Fraunhofer Institute for Physical Measurement, Freiburg (lead)

United Kingdom

  • National Physical Laboratory (NPL), London (lead)

South Korea

  • Korea Electrotechnology Research Institute (KERI) Daejeon (lead)
  • Hanbat National University, Daejeon

International Round-robin Studies of Thermoelectric Materials and Devices
Annex VIII is addressing one of the most important issues facing the thermoelectric community: reliability of transport data. The round-robin results showed significant problems in two of the four measurements that determine the figure of merit (ZT). The test procedures developed by Annex VIII is critical to the transition from laboratory materials development to module and device production. It has significant impact on the commercialization and scale-up and manufacturing of thermoelectric devices.

First international Round-robin study:
The first round-robin on bismuth telluride was conducted in 2010 all the participating labs completed testing two sets of specimens (n-type and p-type). The results showed significant problem in thermal conductivity measurements (thermal diffusivity and specific heat). The largest measurement error came from heat capacity measurements. The Annex round-robin results were well received by the thermoelectric community. It was considered a timely and very important contribution.

Second international Round-robin study:
After the discussion on the first round-robin results, the second round-robin testing began in August of 2010 and was completed by August 2011. Two sets of p-type materials were measured at 7 labs in 4 countries. The results of round-robin 1 were given to all the labs as reference. The issues identified in round-robin 1 were discussed by participating labs. The same test instruments used for round-robin 1 were used for all the transport properties in round-robin two. All the labs completed tests on all specimens. In some cases, thermal and electrical properties testing were carried out at different labs within the same country.

Third international Round-robin study:
The 3rd International round-robin study was carried out from 2013 to 2015 focusing on high temperature (300-800 K) thermoelectric materials for vehicle waste heat recovery. N-type half-Heusler material made by GMZ Energy was used. Transport properties were tested by 13 labs in 6 countries. Following the test procedures developed by the annex, the results show significant improvement in uncertainties of the properties. Due to the error propagation in calculating ZT, scatter among various labs can be expected just above +15%.

Forth international Round-robin study:
While the materials round-robins were coming to an end, annex VIII gather a small international team and conducted a survey of thermoelectric device efficiency testing. The results were published in 2015. From 2015 to 2017, the 4th international round-robin on thermoelectric devices was underway. Bismuth telluride modules from the Marlow Industries were selected for efficiency testing from 300 – 425 K. Test results showed large scatter in efficiency values mainly due to the uncertainties of determining heat flow though the devices.

Other Annex Related Activities:

  • Annex meetings during international Thermoelectric Society annual meetings: ICT2010 Shanghai China, ICT2011 Travers City, MI USA; ICT2012, Aalborg Demark, ICT2013 Kobe Japan, ICT2014 Nashville, TN USA (hosted by ORNL); ICT2015 Dresden Germany, ICT2016 Wuhan China
  • European round-robin studies on thermoelectric materials and devices: Fraunhofer Institute Germany and others (from 2012)
  • International collaboration on thermoelectric materials with IEA-AMT under Ministry of Science and Technology (MOST), SICCAS China

Future Annex Activities:

  • High temperature thermoelectric module efficiency testing
  • Complete development of standard procedures of thermoelectric materials and devices
  • Expand to broader studies of materials used for waste heat recovery of vehicles

Annex Outputs and Publications:
1. International Round-Robin Study of the Thermoelectric Transport Properties of an n-Type Half-Heusler Compound from 300 K to 773 K Journal of Electronic Materials, 44 (11), 4482 (2015)

  • Hsin Wang, Shengqiang Bai, Lidong Chen, Alexander Cuenat, Giri Joshi, Holger Kleinke, Jan König, Hee Woong Lee, Joshua Martin, Min-Wook Oh, Wallace D. Porter, Zhifeng Ren, James Salvador, Jeff Sharp, Patrick Taylor, Alan J Thompson, Yu-Chih Tseng

2. Determination of thermoelectric module efficiency: a survey Journal of Electronic Materials 43 (6), 2274 (2014)

  • Hsin Wang, Robin McCarty, James R Salvador, Atsushi Yamamoto, Jan König

3. Transport properties of bulk thermoelectrics—an international round-robin study, part I: Seebeck coefficient and electrical resistivity Journal of Electronic Materials 42 (4), 654 (2013)

  • Hsin Wang, Wallace D. Porter, Harald Böttner, Jan König, Lidong Chen, Shengqiang Bai, Terry M Tritt, Alex Mayolet, Jayantha Senawiratne, Charlene Smith, Fred Harris, Patricia Gilbert, Jeff W Sharp, Jason Lo, Holger Kleinke, Laszlo Kiss

4. Transport properties of bulk thermoelectrics: an international round-robin study, part II: thermal diffusivity, specific heat, and thermal conductivity Journal of Electronic Materials 42 (6), 1073 (2013)

  • Hsin Wang, Wallace D. Porter, Harald Böttner, Jan König, Lidong Chen, Shengqiang Bai, Terry M Tritt, Alex Mayolet, Jayantha Senawiratne, Charlene Smith, Fred Harris, Patricia Gilbert, Jeff Sharp, Jason Lo, Holger Kleinke, Laszlo Kiss

IEA Topical Report:

  • Annex VIII – Thermoelectric Materials for Waste Heat Recovery: An International Collaboration for Transportation Applications ORNL/TM-2011/393
  • Hsin Wang, Wallace D. Porter, Harald Böttner, Jan König, Lidong Chen, Shengqiang Bai, Terry M Tritt, Alex Mayolet, Jayantha Senawiratne, Charlene Smith, Fred Harris, Patricia Gilbert, Jeff Sharp, Jason Lo, Holger Kleinke, Laszlo Kiss

Annex Chairman - Dr. Hsin Wang
Distinguished R&D Staff
Oak Ridge National Laboratory
Oak Ridge, TN 37831