Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Concentrating solar thermoelectric generators with a peak efficiency of 7.4%

Abstract

Concentrating solar power normally employs mechanical heat engines and is thus only used in large-scale power plants; however, it is compatible with inexpensive thermal storage, enabling electricity dispatchability. Concentrating solar thermoelectric generators (STEGs) have the advantage of replacing the mechanical power block with a solid-state heat engine based on the Seebeck effect, simplifying the system. The highest reported efficiency of STEGs so far is 5.2%. Here, we report experimental measurements of STEGs with a peak efficiency of 9.6% at an optically concentrated normal solar irradiance of 211 kW m−2, and a system efficiency of 7.4% after considering optical concentration losses. The performance improvement is achieved by the use of segmented thermoelectric legs, a high-temperature spectrally selective solar absorber enabling stable vacuum operation with absorber temperatures up to 600 C, and combining optical and thermal concentration. Our work suggests that concentrating STEGs have the potential to become a promising alternative solar energy technology.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: CSTEG concept and proof-of-concept experiment.
Figure 2: Performance characteristics of a STEG optimized for high optical concentration.
Figure 3: Performance characteristics of a STEG optimized for moderate optical concentration.
Figure 4: Theoretical predictions of STEG efficiencies and corresponding optimal solar absorber temperatures.

References

  1. 1

    Jones-Albertus, R., Feldman, D., Fu, R., Horowitz, K. & Woodhouse, M. Technology advances needed for photovoltaics to achieve widespread grid price parity. Prog. Photovolt. Res. Appl. 24, 1272–1283 (2015).

    Article  Google Scholar 

  2. 2

    Luque, A. & Hegedus, S. Handbook of Photovoltaic Science and Engineering (John Wiley, 2003).

    Book  Google Scholar 

  3. 3

    Green, M. A. Third Generation Photovoltaics: Advanced Solar Energy Conversion (Springer, 2003).

    Google Scholar 

  4. 4

    John, A. & Duffie, W. A. B. Solar Engineering of Thermal Processes (Wiley, 2013).

    Google Scholar 

  5. 5

    Mills, D. Advances in solar thermal electricity technology. Sol. Energy 76, 19–31 (2004).

    Article  Google Scholar 

  6. 6

    Weinstein, L. A. et al. Concentrating solar power. Chem. Rev. 115, 12797–12838 (2015).

    Article  Google Scholar 

  7. 7

    Telkes, M. Solar thermoelectric generators. J. Appl. Phys. 25, 765–777 (1954).

    Article  Google Scholar 

  8. 8

    Goldsmid, H. J. Applications of Thermoelectricity (Methuen, 1960).

    Google Scholar 

  9. 9

    Kraemer, D. et al. High-performance flat-panel solar thermoelectric generators with high thermal concentration. Nat. Mater. 10, 532–538 (2011).

    Article  Google Scholar 

  10. 10

    McEnaney, K., Kraemer, D. & Chen, G. Direct heat-to-electricity conversion of solar energy. Annu. Rev. Heat Transfer 15, 179–230 (2012).

    Article  Google Scholar 

  11. 11

    McEnaney, K., Kraemer, D., Ren, Z. & Chen, G. Modeling of concentrating solar thermoelectric generators. J. Appl. Phys. 110, 074502 (2011).

    Article  Google Scholar 

  12. 12

    Venkatasubramanian, R., Siivola, E., Colpitts, T. & O’Quinn, B. Thin-film thermoelectric devices with high room-temperature figures of merit. Nature 413, 597–602 (2001).

    Article  Google Scholar 

  13. 13

    Harman, T. C., Taylor, P. J., Walsh, M. P. & Laforge, B. E. Quantum dot superlattice thermoelectric materials and devices. Science 297, 2229–2232 (2002).

    Article  Google Scholar 

  14. 14

    Dresselhaus, M. S. et al. New directions for low-dimensional thermoelectric materials. Adv. Mater. 19, 1043–1053 (2007).

    Article  Google Scholar 

  15. 15

    Poudel, B. et al. High-thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys. Science 320, 634–638 (2008).

    Article  Google Scholar 

  16. 16

    Heremans, J. P. et al. Enhancement of thermoelectric efficiency in PbTe by distortion of the electronic density of states. Science 321, 1457–1461 (2008).

    Article  Google Scholar 

  17. 17

    Snyder, G. J. & Toberer, E. S. Complex thermoelectric materials. Nat. Mater. 7, 105–114 (2008).

    Article  Google Scholar 

  18. 18

    Biswas, K. et al. High-performance bulk thermoelectrics with all-scale hierarchical architectures. Nature 489, 414–418 (2012).

    Article  Google Scholar 

  19. 19

    Zhao, L.-D. et al. Ultralow thermal conductivity and high thermoelectric figure of merit in SnSe crystals. Nature 508, 373–377 (2014).

    Article  Google Scholar 

  20. 20

    Kim, S. I. et al. Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics. Science 348, 109–114 (2015).

    Article  Google Scholar 

  21. 21

    Beekman, M., Morelli, D. T. & Nolas, G. S. Better thermoelectrics through glass-like crystals. Nat. Mater. 14, 1182–1185 (2015).

    Article  Google Scholar 

  22. 22

    Zhao, L. et al. Ultrahigh power factor and thermoelectric performance in hole-doped single-crystal SnSe. Science 351, 141–144 (2015).

    Article  Google Scholar 

  23. 23

    Kraemer, D., McEnaney, K., Chiesa, M. & Chen, G. Modeling and optimization of solar thermoelectric generators for terrestrial applications. Sol. Energy 86, 1338–1350 (2012).

    Article  Google Scholar 

  24. 24

    Kim, H. S., Liu, W., Chen, G., Chu, C.-W. & Ren, Z. Relationship between thermoelectric figure of merit and energy conversion efficiency. Proc. Natl Acad. Sci. USA 112, 8205–8210 (2015).

    Article  Google Scholar 

  25. 25

    Snyder, G. J. Application of the compatibility factor to the design of segmented and cascaded thermoelectric generators. Appl. Phys. Lett. 84, 2436 (2004).

    Article  Google Scholar 

  26. 26

    Ioffe, A. F. Semiconductor Thermoelements and Thermo-electric Cooling (Infosearch, 1957).

    Google Scholar 

  27. 27

    Rowe, D. M. Thermoelectrics Handbook: Macro to Nano (Taylor & Francis Group, LLC, 2006).

    Google Scholar 

  28. 28

    El-Genk, M. S., Saber, H. H., Sakamoto, J. & Caillat, T. Life tests of a skutterudites thermoelectric unicouple (MAR-03). In 2003, Twenty-Second International Conference on Thermoelectrics – ICT 417–420 (IEEE, 2003); http://dx.doi.org/10.1109/ICT.2003.1287537

  29. 29

    Guo, J. Q. et al. Development of skutterudite thermoelectric materials and modules. J. Electron. Mater. 41, 1036–1042 (2012).

    Article  Google Scholar 

  30. 30

    Muto, A., Yang, J., Poudel, B., Ren, Z. & Chen, G. Skutterudite unicouple characterization for energy harvesting applications. Adv. Energy Mater. 3, 245–251 (2013).

    Article  Google Scholar 

  31. 31

    Caillat, T. et al. Progress status of the development of high-efficiency segmented thermoelectric couples. In Nuclear and Emerging Technologies for Space (2012); http://www.lpi.usra.edu/meetings/nets2012/pdf/3077.pdf

  32. 32

    Kraemer, D. et al. High thermoelectric conversion efficiency of MgAgSb-based material with hot-pressed contacts. Energy Environ. Sci. 8, 1299–1308 (2015).

    Article  Google Scholar 

  33. 33

    Cook, B. A. et al. High-performance three-stage cascade thermoelectric devices with 20% efficiency. J. Electron. Mater. 44, 1936–1942 (2015).

    Article  Google Scholar 

  34. 34

    Salvador, J. R. et al. Conversion efficiency of skutterudite-based thermoelectric modules. Phys. Chem. Chem. Phys. 16, 12510–12520 (2014).

    Article  Google Scholar 

  35. 35

    Goldsmid, H. J., Giutronich, J. E. & Kaila, M. M. Solar thermoelectric generation using bismuth telluride alloys. Sol. Energy 24, 435–440 (1980).

    Article  Google Scholar 

  36. 36

    Dent, C. L. & Cobble, M. H. A solar thermoelectric generator experiments and analysis. in 4th International Conference on Thermoelectric Energy Conversion 75–78 (IEEE, 1982).

  37. 37

    Omer, S. Design optimization of thermoelectric devices for solar power generation. Sol. Energy Mater. Sol. Cells 53, 67–82 (1998).

    Article  Google Scholar 

  38. 38

    Amatya, R. & Ram, R. J. Solar thermoelectric generator for micropower applications. J. Electron. Mater. 39, 1735–1740 (2010).

    Article  Google Scholar 

  39. 39

    Baranowski, L. L., Snyder, G. J. & Toberer, E. S. Concentrated solar thermoelectric generators. Energy Environ. Sci. 5, 9055–9067 (2012).

    Article  Google Scholar 

  40. 40

    Kraemer, D., McEnaney, K., Cao, F., Ren, Z. & Chen, G. Accurate determination of the total hemispherical emittance and solar absorptance of opaque surfaces at elevated temperatures. Sol. Energy Mater. Sol. Cells 132, 640–649 (2015).

    Article  Google Scholar 

  41. 41

    Cao, F. et al. Enhanced thermal stability of W-Ni-Al2O3 cermet-based spectrally selective solar absorbers with tungsten infrared reflectors. Adv. Energy Mater. 5, 1401042 (2015).

    Article  Google Scholar 

  42. 42

    Brandt, R., Bird, C. & Neuer, G. Emissivity reference paints for high temperature applications. Measurement 41, 731–736 (2008).

    Article  Google Scholar 

  43. 43

    Coblentz, W. W. Harnessing heat from the sun. Sci. Am. 127, 324 (1922).

    Article  Google Scholar 

  44. 44

    Durst, T., Harris, L. B. & Goldsmid, H. J. Studies of a thermoelectric generator from tubular solar collectors. Sol. Energy 31, 421–425 (1983).

    Article  Google Scholar 

  45. 45

    NREL Concentrating Solar Power Research (2012); http://www.nrel.gov/csp

  46. 46

    Domenicali, C. A. Irreversible thermodynamics of thermoelectric effects in inhomogeneous, anisotropic media. Phys. Rev. 92, 877–881 (1953).

    Article  Google Scholar 

  47. 47

    Liu, W. et al. Understanding of the contact of nanostructured thermoelectric n-type Bi2Te2.7Se0.3 legs for power generation applications. J. Mater. Chem. A 1, 13093–13100 (2013).

    Article  Google Scholar 

Download references

Acknowledgements

This material is partially based upon work supported as part of the Sunshot Initiative funded by the US Department of Energy, Office of Energy Efficiency & Renewable Energy under Award Number: DE-EE0005806 (for device engineering) and based upon work supported as part of the Solid State Solar-Thermal Energy Conversion Center (S3TEC), an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number: DE-SC0001299/DE-FG02-09ER46577 (for materials).

Author information

Affiliations

Authors

Contributions

D.K. carried out modelling and simulation, CSTEG fabrication and experiments, and prepared the manuscript; Q.J. and W.L. fabricated the thermoelectric and contact materials; K.M. contributed to CSTEG fabrication and experiments and device modelling; F.C. fabricated spectrally selective solar absorbers; L.A.W. contributed to manuscript preparation and CSTEG fabrication and experiments; J.L. contributed to CSTEG fabrication and experiments; Z.R. directed research at UH; G.C. directed research at MIT and contributed to the manuscript preparation.

Corresponding authors

Correspondence to Zhifeng Ren or Gang Chen.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Figures 110, Supplementary Tables 1 and 2, Supplementary Methods and Supplementary References (PDF 1841 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kraemer, D., Jie, Q., McEnaney, K. et al. Concentrating solar thermoelectric generators with a peak efficiency of 7.4%. Nat Energy 1, 16153 (2016). https://doi.org/10.1038/nenergy.2016.153

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing