Passive solar collector

• US 5,648,873 A
• Filed: 05/30/1996
• Issued: 07/15/1997
• Est. Priority Date: 05/30/1996
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Jaster, Paul A., O'Neill, Mark Joseph
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): MALLEY, DANIEL PATRICK
• Application Number:
  US08/655,578
• Time in Patent Office: 411 Days
• Field of Search: 359/591, 359/592, 359/593, 359/594, 359/595, 359/596, 359/597, 359/598
• US Class Current: 359/591
• CPC Class Codes: E04D 2013/034 Daylight conveying tubular skylights
• CPC Class Codes: F21S 11/00 Non-electric lighting devices or systems using daylight roofs with sky-light opening E04D13/03; sun blinds for windows with means for redirecting light onto ceiling of a room E06B9/00; hybrid lighting devices combining artificial and natural light F21S19/00; solar heat collectors F24S; solar cells or solar cell modules H01L31/00
• CPC Class Codes: F24S 23/10 Prisms
• CPC Class Codes: F24S 23/31 having discontinuous faces, e.g. Fresnel lenses
• CPC Class Codes: F24S 23/75 with conical reflective surfaces
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0042 for use with direct solar radiation
• CPC Class Codes: G02B 19/008 adapted to collect light from a complete hemisphere or a plane extending 360 degrees around the detector
• CPC Class Codes: Y02B 10/20 Solar thermal
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers

Abstract

An apparatus designed to direct daylight through an aperture toward a target area in a building or other structure is disclosed. A housing provides a base attachable to the building and a support structure for supporting a reflector above the aperture. According to one embodiment of the invention the reflector is in the shape of an inverted cone. A light diffusing lens structure is disposed in the optical path between the reflector and the target area. In use, light is transmitted through the support structure, reflected from the surface of the reflector, and dispersed about the target area by the light diffusing lens structure.

Claims

1. An apparatus for directing sunlight through an aperture in a structure toward a target area, comprising:

passive reflector means for reflecting sunlight toward said target area, said passive reflector means having an upper portion that extends through an arc having a radius of curvature R₁ and a lower portion that extends through an arc having a radius of curvature R₂, less than R₁,

light spreading means displaced from said passive reflector means for spreading light reflected from said passive reflector means; and

support means for holding said passive reflector means in a fixed spatial relationship with said light spreading means such that a first portion of the sunlight incident on said apparatus is reflected from said passive reflector means toward said light spreading means and through said aperture.

2. An apparatus according to claim 1, wherein:

said passive reflector means is positioned to receive direct sunlight.

3. An apparatus according to claim 1, wherein:

said passive reflector means comprises a reflective surface that subtends an angle of at least 180 degrees.

4. An apparatus according to claim 1, wherein:

said passive reflector means comprises a reflective surface that subtends an angle of 360 degrees.

5. An apparatus according to claim 1, wherein:

said passive reflector means comprises a specularly reflective coating.

6. An apparatus according to claim 1, wherein:

said passive reflector means comprises an array of linear prisms.

7. An apparatus according to claim 1, wherein:

said passive reflector means comprises a substantially conical reflector oriented such that its peak faces said light spreading means.

8. An apparatus according to claim 1, wherein:

said passive reflector means comprises a substantially frusto-conical reflector oriented such that its peak faces said light spreading means.

9. An apparatus according to claim 1, wherein:

said passive reflector means comprises a multi-sided reflector oriented such that its peak faces said light spreading means.

10. An apparatus according to claim 1, wherein:

said light spreading means comprises a light diffuser.

11. An apparatus according to claim 1, wherein:

said light spreading means comprises a diverging lens.

12. An apparatus according to claim 1, wherein:

said light spreading means comprises a diverging fresnel lens.

13. An apparatus according to claim 1, wherein:

said light spreading means comprises a diverging linear lens.

14. An apparatus according to claim 1, wherein:

said light spreading means comprises a diverging radial lens.

15. An apparatus according to claim 1, wherein:

said support means comprises a housing formed from a substantially optically transparent material.

16. An apparatus according to claim 15, wherein:

said housing has a base having a radius R1 and a top having a radius R2, less than R1.

17. An apparatus according to claim 11, wherein:

the ratio of R1;

R2 is between 1.05;

1 and 1.5;

1.

18. An apparatus for directing daylight through an aperture into a building, comprising:

a housing having a base attachable to the building and a support structure formed from a substantially optically transparent material extending from the base;

an optical reflector assembly having a base secured to the support structure, the optical reflector assembly comprising a reflective surface having an upper portion that extends through an arc having a radius of curvature R₁ and a lower portion that extends through an arc having a radius of curvature R₂, less than R₁, and

a light spreading lens disposed adjacent the bottom surface of said housing,

such that daylight incident on the system at solar altitude angles between about 0 and 50 degrees is transmitted through the optically transparent housing, strikes a portion of the reflective surface of the conical reflector, and is directed through the light spreading lens toward and into the building.