Abstract

The maximum concentration of radiation is proportional to the square of the refractive index of the medium in which it propagates. A medium with a high refractive index can also serve as a lightguide for concentrated radiation. However, if concentrated radiation is extracted from one medium, with a high refractive index, to another, whose index is lower (e.g., from fused silica into air), part of the radiation may be lost because of the total internal reflection at the interface. We present polygonal shapes suitable for efficient extraction of the concentrated radiation in a controllable way, without increasing the cross-section area (or diameter) of the lightguide. It is shown analytically and experimentally that the use of a secondary concentrator, followed by such a light extractor, both having a high refractive index, can provide considerably more power to a solar receiver with a specific aperture.

© 1997 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. T. Welford, R. Winston, High Collection Non-Imaging Optics (Academic, New York, 1989).
  2. J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).
  3. H. Ries, W. Spirkl, R. Winston, “Cone and trumpet concentrators in the light of the general edge-ray theorem,” in Nonimaging Optics: Maximum Efficiency Light Transfer III, R. Winston, ed., Proc. SPIE2538, 10–15 (1995).
  4. H. Ries, A. Rabl, “The edge ray principle of nonimaging optics,” J. Opt. Soc. Am. A 11, 2627–2632 (1994). Also included in R. Winston, ed., Selected Papers in Nonimaging Optics, SPIE Milestone Series Vol. MS 106 (SPIE Optical Engineering Press, Bellingham, Mass., 1995).
  5. J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).
  6. D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
    [CrossRef]

1997 (1)

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

1996 (1)

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

1994 (1)

Bingham, C.

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

Bliss, J.

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

Doron, P.

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

Fiterman, A.

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

Jenkins, D.

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

Karni, J.

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).

Kribus, A.

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

Krupkin, V.

J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).

Lewandowski, A.

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

O’Gallagher, J.

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

Rabl, A.

Ries, H.

H. Ries, A. Rabl, “The edge ray principle of nonimaging optics,” J. Opt. Soc. Am. A 11, 2627–2632 (1994). Also included in R. Winston, ed., Selected Papers in Nonimaging Optics, SPIE Milestone Series Vol. MS 106 (SPIE Optical Engineering Press, Bellingham, Mass., 1995).

J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).

H. Ries, W. Spirkl, R. Winston, “Cone and trumpet concentrators in the light of the general edge-ray theorem,” in Nonimaging Optics: Maximum Efficiency Light Transfer III, R. Winston, ed., Proc. SPIE2538, 10–15 (1995).

Sagie, D.

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

Segal, A.

J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).

Spirkl, W.

H. Ries, W. Spirkl, R. Winston, “Cone and trumpet concentrators in the light of the general edge-ray theorem,” in Nonimaging Optics: Maximum Efficiency Light Transfer III, R. Winston, ed., Proc. SPIE2538, 10–15 (1995).

Welford, W. T.

W. T. Welford, R. Winston, High Collection Non-Imaging Optics (Academic, New York, 1989).

Winston, R.

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

W. T. Welford, R. Winston, High Collection Non-Imaging Optics (Academic, New York, 1989).

H. Ries, W. Spirkl, R. Winston, “Cone and trumpet concentrators in the light of the general edge-ray theorem,” in Nonimaging Optics: Maximum Efficiency Light Transfer III, R. Winston, ed., Proc. SPIE2538, 10–15 (1995).

Yogev, A.

J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).

ASME J. Sol. Energ. Eng. (1)

D. Jenkins, R. Winston, J. Bliss, J. O’Gallagher, A. Lewandowski, C. Bingham, “Solar concentration of 50,000 achieved with output power approaching 1 kW,” ASME J. Sol. Energ. Eng. 118, 141–145 (1996).
[CrossRef]

ASME J. Sol. Energy Eng. (1)

J. Karni, A. Kribus, P. Doron, A. Fiterman, D. Sagie, “The DIAPR; A high-pressure, high-temperature solar receiver,” ASME J. Sol. Energy Eng. 119 (February1997).

J. Opt. Soc. Am. A (1)

Other (3)

W. T. Welford, R. Winston, High Collection Non-Imaging Optics (Academic, New York, 1989).

J. Karni, H. Ries, A. Segal, V. Krupkin, A. Yogev, “Delivery of radiation from a transparent medium,” International patent applicationPCT/US95/04915, Publication WO95/29415 (1995).

H. Ries, W. Spirkl, R. Winston, “Cone and trumpet concentrators in the light of the general edge-ray theorem,” in Nonimaging Optics: Maximum Efficiency Light Transfer III, R. Winston, ed., Proc. SPIE2538, 10–15 (1995).

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (7)

Fig. 1
Fig. 1

Direction of a given ray is described by a vector k normalized to the index of refraction n. The coordinate system is defined by the axial, radial and tangential directions k a , k r , and k t .

Fig. 2
Fig. 2

Radial versus tangential components of the ray direction at the outer surface of a circular lightguide. The outer circular boundary at radius equal to n defines the limit at which a ray is turned back and rejected. The vertical straight line represents the limit at which a ray is extracted. As the radius of the tapered lightguide decreases, each ray moves outward along a straight line, k t*/k r * = constant. Thus the rays initially below the dotted line will eventually be extracted whereas those above this line will be rejected by a circularly symmetric device.

Fig. 3
Fig. 3

Radial versus tangential components of the ray direction at a certain location in a cross section. The outer circular boundary defines all rays. The elliptical curve encloses those rays that can be guided by a cylinder. The rays below the dotted line are extracted if the cross section is slowly decreased while remaining circular in shape; the rays above the dotted line are turned back. The phase space is proportional to the area enclosed.

Fig. 4
Fig. 4

Various portions of the light filling the cross section of a circular wave guide as a function of the index of refraction n: a, the fraction extractable with this waveguide; b, maximum fraction of diffuse radiation guidable by this waveguide; c, the fraction that is both guidable and extractable. The waveguide is assumed to be filled with diffuse radiation, uniformly distributed over the hemispheric phase space.

Fig. 5
Fig. 5

Ray-trace simulations of the extraction of rays from a cylindrical waveguide terminated in a circular cone, a regular hexagonal prism (asterisk), and a regular triangular prism (triangle) as a function of the ratio between the extractor length H and its initial radius R. The waveguide is uniformly filled with all the radiation it can guide.

Fig. 6
Fig. 6

Secondary concentrator at the Weizmann Institute, fitted with a TIR terminal stage that is ended in an extractor. It delivers the radiation into a volumetric air receiver.

Fig. 7
Fig. 7

Model hexagonal extractor, illuminated by a diffuse light source. The uniform brightness of the part adjacent to the tip indicates the extracted radiation.

Equations (16)

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

Cmax=n2sin2 θ,
ka2+kr2+kt2=n2.
z1=R11R/z
T=kr1*z1n.
nRkr*=conserved.
nRkt*=s=conserved.
kr2+kt2 < n2.
ka*2+kt*2 > 1.
kr2+1-r2kt2 < n2-1.
ηgr=n2-1n21-r21/2for 0  r  1n2πarcsin1-1n2r21/2+n2-1n21-r21/2 arcsin1-r2r2n2-11/2for 1n  r  1.
ηexr=n2-1n21-r21/2for 0  r  1n2πn2-1n21-r21/2 arcsin1-r2r2n2-11/2for 1n  r  1.
ηgn=2 01rηgrdr=2n2-1n2-2n2πn2-11/2+22-n2n2π arctan n2-11/2.
ηexn=2 01 rηexrdr=2n2-1n2×1-2π arctan n2-11/2.
R=Rϕ, z,
Rϕ  0.
Rϕ  0.

Metrics