Abstract

Solar thermal, thermoelectric, and thermophotovoltaic (TPV) systems have high maximum theoretical efficiencies; experimental systems fall short because of losses by selective solar absorbers and TPV selective emitters. To improve these critical components, we study a class of materials known as cermets. While our approach is completely general, the most promising cermet candidate combines nanoparticles of silica and tungsten. We find that 4-layer silica-tungsten cermet selective solar absorbers can achieve thermal transfer efficiencies of 84.3% at 400 K, and 75.59% at 1000 K, exceeding comparable literature values. Three layer silica-tungsten cermets can also be used as selective emitters for InGaAsSb-based thermophotovoltaic systems, with projected overall system energy conversion efficiencies of 10.66% at 1000 K using realistic design parameters. The marginal benefit of adding more than 4 cermet layers is small (less than 0.26%, relative).

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References

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  1. W. Spirkl and H. Ries, “Solar thermophotovoltaics: an assessment,” J. Appl. Phys. 57, 4409–4414 (1985).
    [CrossRef]
  2. D. Y. Goswami, F. Kreith, and J. F. Kreider, Principles of Solar Engineering (Taylor and Francis, 2000).
  3. F. J. DiSalvo, “Thermoelectric cooling and power generation,” Science 285, 703–706 (1999).
    [CrossRef] [PubMed]
  4. G. Chen, Nanoscale Energy Transport and Conversion: a Parallel Treatment of Electrons, Molecules, Phonons, and Photons (Oxford University Press, 2005).
    [PubMed]
  5. H. H. Kolm, “Solar-battery power source,” Quarterly Progress Report (1956), Group 35, p. 13.
  6. B. Wedlock, “Thermo-photo-voltaic conversion,” Proc. IEEE 51, 694–698 (1963).
    [CrossRef]
  7. R. Black, P. Baldasaro, and G. Charache, “Thermophotovoltaics - development status and parametric considerations for power applications,” in International Conference on Thermoelectrics (IEEE, 1999), Vol. 18, pp. 639–644.
  8. F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
    [CrossRef]
  9. N. Harder and P. Wurfel, “Theoretical limits of thermophotovoltaic solar energy conversion,” Semicond. Sci. Technol. 18, S151–S157 (2003).
    [CrossRef]
  10. P. Bermel, M. Ghebrebrhan, W. Chan, Y. X. Yeng, M. Araghchini, R. Hamam, C. H. Marton, K. F. Jensen, M. Soljacic, J. D. Joannopoulos, S. G. Johnson, and I. Celanovic, “Design and global optimization of high-efficiency thermophotovoltaic systems,” Opt. Express 18, A314–A334 (2010).
    [CrossRef] [PubMed]
  11. G. Rybicki and A. Lightman, Radiative processes in astrophysics (John Wiley and Sons, 1979).
  12. C. Kennedy, “Review of mid- to high-temperature solar selective absorber materials,” Tech. Rep. TP-520-31267, National Renewable Energy Laboratory (2002).
  13. T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
    [CrossRef]
  14. Q.-C. Zhang, “High efficiency Al-N cermet solar coatings with double cermet layer film structures,” J. Phys. D: Appl. Phys. 32, 1938–1944 (1999).
    [CrossRef]
  15. P. Bienstman, “Rigorous and efficient modelling of wavelength scale photonic components,” Ph.D. thesis, University of Ghent, Belgium (2001).
  16. A. Rakic, A. Djurisic, J. Elazar, and M. Majewski, “Optical properties of metallic films for vertical-cavity opto-electronic devices,” Appl. Opt. 37, 5271–5283 (1998).
    [CrossRef]
  17. E. D. Palik, ed., Handbook of Optical Constants of Solids (Academic Press, 1998), Vol. 1.
  18. R. Landauer, “Electrical conductivity in inhomogeneous media,” (American Institute of Physics, 1978), Vol. 40, pp. 2–45.
  19. P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
    [CrossRef]
  20. I. Celanovic, D. Perreault, and J. Kassakian, “Resonant-cavity enhanced thermal emission,” Phys. Rev. B 72, 075127 (2005).
    [CrossRef]
  21. S. Roberts, “Optical properties of nickel and tungsten and their interpretation according to Drude’s formula,” Phys. Rev. 114, 104–115 (1959).
    [CrossRef]
  22. S. Kucherenko and Y. Sytsko, “Application of deterministic low-discrepancy sequences in global optimization,” Comput. Optim. Appl. 30, 297–318 (2005).
    [CrossRef]
  23. M. Powell, Advances in Optimization and Numerical Analysis (Kluwer Academic, 1994), pp. 51–67.
  24. M. Ghebrebrhan, P. Bermel, Y. Avniel, J. D. Joannopoulos, and S. G. Johnson, “Global optimization of silicon photovoltaic cell front coatings,” Opt. Express 17, 7505–7518 (2009).
    [CrossRef] [PubMed]

2010 (1)

2009 (1)

2005 (3)

S. Kucherenko and Y. Sytsko, “Application of deterministic low-discrepancy sequences in global optimization,” Comput. Optim. Appl. 30, 297–318 (2005).
[CrossRef]

I. Celanovic, D. Perreault, and J. Kassakian, “Resonant-cavity enhanced thermal emission,” Phys. Rev. B 72, 075127 (2005).
[CrossRef]

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

2004 (1)

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

2003 (1)

N. Harder and P. Wurfel, “Theoretical limits of thermophotovoltaic solar energy conversion,” Semicond. Sci. Technol. 18, S151–S157 (2003).
[CrossRef]

1999 (2)

F. J. DiSalvo, “Thermoelectric cooling and power generation,” Science 285, 703–706 (1999).
[CrossRef] [PubMed]

Q.-C. Zhang, “High efficiency Al-N cermet solar coatings with double cermet layer film structures,” J. Phys. D: Appl. Phys. 32, 1938–1944 (1999).
[CrossRef]

1998 (1)

1990 (1)

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

1985 (1)

W. Spirkl and H. Ries, “Solar thermophotovoltaics: an assessment,” J. Appl. Phys. 57, 4409–4414 (1985).
[CrossRef]

1963 (1)

B. Wedlock, “Thermo-photo-voltaic conversion,” Proc. IEEE 51, 694–698 (1963).
[CrossRef]

1959 (1)

S. Roberts, “Optical properties of nickel and tungsten and their interpretation according to Drude’s formula,” Phys. Rev. 114, 104–115 (1959).
[CrossRef]

1956 (1)

H. H. Kolm, “Solar-battery power source,” Quarterly Progress Report (1956), Group 35, p. 13.

Agnihotri, O.

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

Akiyama, S.

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

Araghchini, M.

Avniel, Y.

Baldasaro, P.

R. Black, P. Baldasaro, and G. Charache, “Thermophotovoltaics - development status and parametric considerations for power applications,” in International Conference on Thermoelectrics (IEEE, 1999), Vol. 18, pp. 639–644.

Bermel, P.

Bhatnagar, M.

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

Black, R.

R. Black, P. Baldasaro, and G. Charache, “Thermophotovoltaics - development status and parametric considerations for power applications,” in International Conference on Thermoelectrics (IEEE, 1999), Vol. 18, pp. 639–644.

Celanovic, I.

P. Bermel, M. Ghebrebrhan, W. Chan, Y. X. Yeng, M. Araghchini, R. Hamam, C. H. Marton, K. F. Jensen, M. Soljacic, J. D. Joannopoulos, S. G. Johnson, and I. Celanovic, “Design and global optimization of high-efficiency thermophotovoltaic systems,” Opt. Express 18, A314–A334 (2010).
[CrossRef] [PubMed]

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

I. Celanovic, D. Perreault, and J. Kassakian, “Resonant-cavity enhanced thermal emission,” Phys. Rev. B 72, 075127 (2005).
[CrossRef]

Chan, W.

Charache, G.

R. Black, P. Baldasaro, and G. Charache, “Thermophotovoltaics - development status and parametric considerations for power applications,” in International Conference on Thermoelectrics (IEEE, 1999), Vol. 18, pp. 639–644.

Chen, G.

G. Chen, Nanoscale Energy Transport and Conversion: a Parallel Treatment of Electrons, Molecules, Phonons, and Photons (Oxford University Press, 2005).
[PubMed]

DiSalvo, F. J.

F. J. DiSalvo, “Thermoelectric cooling and power generation,” Science 285, 703–706 (1999).
[CrossRef] [PubMed]

Djurisic, A.

Elazar, J.

Fischer, B.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Ghebrebrhan, M.

Goswami, D. Y.

D. Y. Goswami, F. Kreith, and J. F. Kreider, Principles of Solar Engineering (Taylor and Francis, 2000).

Haglund, R.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Hamam, R.

Harder, N.

N. Harder and P. Wurfel, “Theoretical limits of thermophotovoltaic solar energy conversion,” Semicond. Sci. Technol. 18, S151–S157 (2003).
[CrossRef]

Helm, H.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Jensen, K. F.

Jepsen, P.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Joannopoulos, J. D.

Johnson, S. G.

Jovanovic, N.

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

Kassakian, J.

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

I. Celanovic, D. Perreault, and J. Kassakian, “Resonant-cavity enhanced thermal emission,” Phys. Rev. B 72, 075127 (2005).
[CrossRef]

Kolm, H. H.

H. H. Kolm, “Solar-battery power source,” Quarterly Progress Report (1956), Group 35, p. 13.

Kreider, J. F.

D. Y. Goswami, F. Kreith, and J. F. Kreider, Principles of Solar Engineering (Taylor and Francis, 2000).

Kreith, F.

D. Y. Goswami, F. Kreith, and J. F. Kreider, Principles of Solar Engineering (Taylor and Francis, 2000).

Kucherenko, S.

S. Kucherenko and Y. Sytsko, “Application of deterministic low-discrepancy sequences in global optimization,” Comput. Optim. Appl. 30, 297–318 (2005).
[CrossRef]

Landauer, R.

R. Landauer, “Electrical conductivity in inhomogeneous media,” (American Institute of Physics, 1978), Vol. 40, pp. 2–45.

Lightman, A.

G. Rybicki and A. Lightman, Radiative processes in astrophysics (John Wiley and Sons, 1979).

Lopez, R.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Majewski, M.

Marton, C. H.

O’Sullivan, F.

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

Perreault, D.

I. Celanovic, D. Perreault, and J. Kassakian, “Resonant-cavity enhanced thermal emission,” Phys. Rev. B 72, 075127 (2005).
[CrossRef]

Powell, M.

M. Powell, Advances in Optimization and Numerical Analysis (Kluwer Academic, 1994), pp. 51–67.

Rakic, A.

Ries, H.

W. Spirkl and H. Ries, “Solar thermophotovoltaics: an assessment,” J. Appl. Phys. 57, 4409–4414 (1985).
[CrossRef]

Roberts, S.

S. Roberts, “Optical properties of nickel and tungsten and their interpretation according to Drude’s formula,” Phys. Rev. 114, 104–115 (1959).
[CrossRef]

Rybicki, G.

G. Rybicki and A. Lightman, Radiative processes in astrophysics (John Wiley and Sons, 1979).

Sathiaraj, T.

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

Sharbaty, A.

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

Soljacic, M.

Spirkl, W.

W. Spirkl and H. Ries, “Solar thermophotovoltaics: an assessment,” J. Appl. Phys. 57, 4409–4414 (1985).
[CrossRef]

Suh, J.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Sytsko, Y.

S. Kucherenko and Y. Sytsko, “Application of deterministic low-discrepancy sequences in global optimization,” Comput. Optim. Appl. 30, 297–318 (2005).
[CrossRef]

Thangarj, R.

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

Thoman, A.

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

Wada, K.

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

Wedlock, B.

B. Wedlock, “Thermo-photo-voltaic conversion,” Proc. IEEE 51, 694–698 (1963).
[CrossRef]

Wurfel, P.

N. Harder and P. Wurfel, “Theoretical limits of thermophotovoltaic solar energy conversion,” Semicond. Sci. Technol. 18, S151–S157 (2003).
[CrossRef]

Yeng, Y. X.

Zhang, Q.-C.

Q.-C. Zhang, “High efficiency Al-N cermet solar coatings with double cermet layer film structures,” J. Phys. D: Appl. Phys. 32, 1938–1944 (1999).
[CrossRef]

Appl. Opt. (1)

Comput. Optim. Appl. (1)

S. Kucherenko and Y. Sytsko, “Application of deterministic low-discrepancy sequences in global optimization,” Comput. Optim. Appl. 30, 297–318 (2005).
[CrossRef]

J. Appl. Phys. (2)

W. Spirkl and H. Ries, “Solar thermophotovoltaics: an assessment,” J. Appl. Phys. 57, 4409–4414 (1985).
[CrossRef]

F. O’Sullivan, I. Celanovic, N. Jovanovic, J. Kassakian, S. Akiyama, and K. Wada, “Optical characteristics of 1D Si/SiO2 photonic crystals for thermophotovoltaic applications,” J. Appl. Phys. 97, 033529 (2005).
[CrossRef]

J. Phys. D: Appl. Phys. (1)

Q.-C. Zhang, “High efficiency Al-N cermet solar coatings with double cermet layer film structures,” J. Phys. D: Appl. Phys. 32, 1938–1944 (1999).
[CrossRef]

Opt. Express (2)

Phys. Rev. (1)

S. Roberts, “Optical properties of nickel and tungsten and their interpretation according to Drude’s formula,” Phys. Rev. 114, 104–115 (1959).
[CrossRef]

Phys. Rev. B (2)

P. Jepsen, B. Fischer, A. Thoman, H. Helm, J. Suh, R. Lopez, and R. Haglund, “Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy,” Phys. Rev. B 74, 205103 (2004).
[CrossRef]

I. Celanovic, D. Perreault, and J. Kassakian, “Resonant-cavity enhanced thermal emission,” Phys. Rev. B 72, 075127 (2005).
[CrossRef]

Proc. IEEE (1)

B. Wedlock, “Thermo-photo-voltaic conversion,” Proc. IEEE 51, 694–698 (1963).
[CrossRef]

Quarterly Progress Report (1)

H. H. Kolm, “Solar-battery power source,” Quarterly Progress Report (1956), Group 35, p. 13.

Science (1)

F. J. DiSalvo, “Thermoelectric cooling and power generation,” Science 285, 703–706 (1999).
[CrossRef] [PubMed]

Semicond. Sci. Technol. (1)

N. Harder and P. Wurfel, “Theoretical limits of thermophotovoltaic solar energy conversion,” Semicond. Sci. Technol. 18, S151–S157 (2003).
[CrossRef]

Thin Solid Films (1)

T. Sathiaraj, R. Thangarj, A. Sharbaty, M. Bhatnagar, and O. Agnihotri, “Ni-Al2O3 selective cermet coatings for photochemical conversion up to 500° C,” Thin Solid Films 190, 241 (1990).
[CrossRef]

Other (9)

G. Rybicki and A. Lightman, Radiative processes in astrophysics (John Wiley and Sons, 1979).

C. Kennedy, “Review of mid- to high-temperature solar selective absorber materials,” Tech. Rep. TP-520-31267, National Renewable Energy Laboratory (2002).

P. Bienstman, “Rigorous and efficient modelling of wavelength scale photonic components,” Ph.D. thesis, University of Ghent, Belgium (2001).

E. D. Palik, ed., Handbook of Optical Constants of Solids (Academic Press, 1998), Vol. 1.

R. Landauer, “Electrical conductivity in inhomogeneous media,” (American Institute of Physics, 1978), Vol. 40, pp. 2–45.

R. Black, P. Baldasaro, and G. Charache, “Thermophotovoltaics - development status and parametric considerations for power applications,” in International Conference on Thermoelectrics (IEEE, 1999), Vol. 18, pp. 639–644.

G. Chen, Nanoscale Energy Transport and Conversion: a Parallel Treatment of Electrons, Molecules, Phonons, and Photons (Oxford University Press, 2005).
[PubMed]

D. Y. Goswami, F. Kreith, and J. F. Kreider, Principles of Solar Engineering (Taylor and Francis, 2000).

M. Powell, Advances in Optimization and Numerical Analysis (Kluwer Academic, 1994), pp. 51–67.

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Figures (8)

Fig. 1
Fig. 1

Schematic illustration of a solar TPV system. Sunlight is collected via optical concentrators and sent to a selectively absorbing surface. That structure is thermally coupled to a selective emitter, which in conjunction with a filter, thermally emits photons with energies matched to the semiconductor bandgap of the TPV cell receiving them.

Fig. 2
Fig. 2

Diagram depicting the layers of the cermet structures examined in this manuscript, which include a dielectric AR coating, back reflector, and 1–4 cermet layers in between.

Fig. 3
Fig. 3

Behavior of the dielectric constants associated with the Bruggeman approximation (a) as a function of metal volume fraction (λ = 2μm) (b) as a function of wavelength (real part) and (c) as a function of wavelength (imaginary part).

Fig. 4
Fig. 4

Emissivity spectrum of tungsten for various temperatures both in experiment (circles) and in our numerical model (lines).

Fig. 5
Fig. 5

The figure of merit for a two-layer cermet selective absorber as a function of cermet thicknesses for the first and second layers. The rest of the parameters are from the optimized two layer structure, with the other parameters set identical to the selective solar absorber at 400 K given in Table 3(b).

Fig. 6
Fig. 6

For silica-tungsten cermet selective absorbers with C=1 at 400 K: (a) Optimized reflection spectra for 1–4 layer structures (b) corresponding metal volume fractions as a function of thickness for optimized structures of 1–4 layers.

Fig. 7
Fig. 7

For silica-tungsten cermet selective absorbers with C=100 at 1000 K: (a) Optimized reflection spectra for 1–4 layer structures (b) corresponding metal volume fractions as a function of thickness for optimized structures of 1–4 layers.

Fig. 8
Fig. 8

For silica-tungsten cermet selective emitters at 1000 K: (a) Optimized emissivity spectra for 1–4 layer structures (b) Metal volume fraction as a function of thickness for optimized 1–4 layer structures.

Tables (3)

Tables Icon

Table 3 Parameters for 1–4 Layer Tungsten–Silica Cermet Structures at 400 K and 1000 K for (a) 1-Layer Cermets, (b) 2-Layer Cermets, (c) 3-Layer Cermets, and (d) 4-Layer Cermets (All Thicknesses in nm)

Tables Icon

Table 1 Spectrally Averaged Absorptivities α, Emissivities ɛ, and Thermal Transfer Efficiencies ηt for 1–4 Layer Tungsten–Silica Cermet Structures (Illustrated in Fig. 2) Compared to Other Selective Absorbers at 400 K with Unconcentrated Sunlight, and 1000 K with Concentration of 100 Suns

Tables Icon

Table 2 Overall Figures of Merit (Defined as Efficiency Times Power Output of System Based on Ref. [10]) for 1–4 Layer Tungsten–Silica Cermet Selective Emitter Structures

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

η t = 1 C I 0 d λ ɛ ( λ ) [ B d I d λ π h c 2 λ 4 ( exp ( h c / λ k T ) 1 ] B α ɛ σ T 4 C I ,
v= ε m ε ε m +2ε +(1v) ε d ε ε d +2ε =0,
Γ o ( T ) = Γ o ( T o ) ( T T o ) α .

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