Solar lighting reflector apparatus having slatted mirrors and improved tracker

• US 4,883,340 A
• Filed: 08/02/1988
• Issued: 11/28/1989
• Est. Priority Date: 08/02/1988
• Status: Expired due to Term

• Current Assignee: SNS Technology LLC
• Original Assignee: Solar Lighting Research Incorporated
• Inventors: Dominguez, Richard L.
• Primary Examiner(s): WINTERCORN, RICHARD
• Application Number:
  US07/227,239
• Time in Patent Office: 483 Days
• Field of Search: 350/258, 350/260, 350/264, 350/263, 362/35, 362/32, 126/425, 136/246, 250/203 R
• US Class Current: 359/593
• 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: F21V 17/02 with provision for adjustment F21V17/04 - F21V17/08 take precedence
• CPC Class Codes: F21V 23/00 Arrangement of electric circuit elements in or on lighting devices characterised by cooling arrangements F21V29/508
• CPC Class Codes: F24S 2020/16 Preventing shading effects
• CPC Class Codes: F24S 2030/145 Tracks
• CPC Class Codes: F24S 23/77 with flat reflective plates
• CPC Class Codes: F24S 30/452 Vertical primary axis
• CPC Class Codes: G02B 7/183 specially adapted for very large mirrors, e.g. for astronomy, or solar concentrators
• CPC Class Codes: Y02B 10/20 Solar thermal
• CPC Class Codes: Y02E 10/47 Mountings or tracking

Abstract

A solar lighting apparatus for illuminating the interior of a roofed building includes a reflector assembly rotatable about a vertical axis for tracking daily movements of the sun. The reflector assembly includes multiple planar reflector panels each extending about a horizontal axis and supported between a pair of opposing, parallel side frame members inclined upwardly toward their rear ends at approximately a 25° angle to the horizontal. The reflector panels are oriented in their operative position at right angles to the side frame members and are inclined at approximately a 65° angle to the horizontal. The reflector panels are spaced apart from one another by a distance approximating the width of each panel to prevent leading reflector panels from shading trailing reflector panels. Each of the reflector panels is secured to the side frame members about a pivotal connection for allowing the reflector panels to be rotated to a compact shipping position lying substantially within the plane defined by the side frame members. The reflector assembly is supported by a rotatable support ring geared to a drive motor selectively powered from a storage battery that is in turn charged by a first photovoltaic panel. A solar tracking circuit selectively couples the storage battery to the drive motor for rotating the reflector assembly. A second smaller photovoltaic panel directly powers the tracking circuitry to avoid draining the storage battery. The tracking circuitry prevents false tracking under cloudy-bright conditions, and automatically seeks the sun following extended hours of overcast conditions.

Claims

1. A solar lighting reflector apparatus for illuminating the interior of a roofed building during daylight hours and adapted to follow daily movements of the sun, the roofed building having a light transmissive opening in the roof therein, said apparatus comprising in combination:

a. a base;

b. means for rotatably supporting the base above the light transmissive opening of the roofed building;

c. a plurality of generally planar reflective panels for reflecting sunlight into the light transmissive opening, each of the reflective panels extending between first and second opposing ends along a generally horizontal longitudinal axis, the longitudinal axes of the plurality of reflective panels being parallel to each other, each of the plurality of reflective panels being supported by the base for rotation therewith, the plurality of reflective panels including at least a frontmost reflective panel and a rearmost reflective panel;

d. the rearmost reflective panel being supported at a higher elevation than the frontmost reflective panel to avoid shading of the rearmost reflective panel by the frontmost reflective panel; and

e. tracking means for rotating the base to direct the reflective panels toward the sun as the sun moves throughout each day.

2. A solar lighting reflector apparatus as recited by claim 1 further including a pair of opposing side frame members extending generally parallel to each other, the pair of side frame members being supported above the base on opposing sides thereof for rotation therewith and being spaced apart from each other by a predetermined distance, each of the side frame members extending between a front end and a rear end thereof, each of the side frame members being inclined upwardly from the front end thereof toward the rear end thereof, and wherein each of the plurality of reflective panels is secured at its first end to one of the side frame members and is secured at its second end to the other of the side frame members.

3. A solar lighting reflector apparatus as recited by claim 2 wherein each of the side frame members is substantially linear and wherein each of the reflective panels lies in a plane that is substantially perpendicular to the side frame members.

4. A solar lighting reflector apparatus as recited by claim 3 wherein each of the reflective panels lies in a plane that is inclined at approximately 65°

to the horizontal, and wherein the side frame members are oppositely inclined at approximately 25°

to the horizontal.

5. A solar lighting reflector apparatus as recited by claim 2 wherein each of the side frame members is substantially linear and wherein each of the reflective panels is secured to the side frame members about a pivotal connection for allowing each of the reflective panels to be pivoted to an inoperative position lying substantially within the plane defined by the side frame members for providing a compact unit for shipping.

6. A solar lighting reflector apparatus as recited by claim 5 wherein the side frame members include lock means for selectively locking each of the reflective panels in an operative position in a plane that is substantially perpendicular to the side frame members.

7. A solar lighting reflector apparatus as recited by claim 1 wherein each of the reflective panels has a width dimension measured perpendicular to its longitudinal axis, the reflective panels having a common predetermined width, and wherein each reflective panel is spaced apart from adjacent reflective panels by substantially said predetermined width.

8. A solar lighting reflector apparatus as recited by claim 4 wherein each of the reflective panels has a width dimension measured perpendicular to its longitudinal axis, the reflective panels having a common predetermined width, and wherein each reflective panel is spaced apart from adjacent reflective panels by substantially said predetermined width to further minimize shading of one reflective panel by another reflective panel in front thereof.

9. A solar lighting reflector apparatus as recited by claim 5 wherein each of the reflective panels has a width dimension measured perpendicular to its longitudinal axis, the reflective panels having a common predetermined width, and wherein each reflective panel is spaced apart from adjacent reflective panels by substantially said predetermined width to further minimize shading of one reflective panel by another reflective panel in front thereof, and for permitting the reflective panels to be pivoted within the plane defined by the side frame members.

10. A solar lighting reflector apparatus for illuminating the interior of a roofed building during daylight hours and adapted to follow daily movements of the sun, the roofed building having a light transmissive opening in the roof therein, said apparatus comprising in combination:

a. a base;

b. means for rotatably supporting the base above the light transmissive opening of the roofed building;

c. reflector means secured to the base for rotation therewith, the reflector means reflecting solar light into the light transmissive opening;

d. a drive motor for rotating the base and the reflector means along therewith;

e. a storage battery for storing electrical power used to operate the drive motor;

f. a first photovoltaic panel for generating electrical power to charge the storage battery;

g. tracking means for detecting the position of the sun and for generating at least one control signal in response thereto;

h. control means responsive to the at least one control signal for selectively coupling electrical power from the storage battery to the drive motor for rotating the base and the reflector means to follow daily movements of the sun; and

i. a second photovoltaic panel electrically coupled to the tracking means and control means for supplying electrical power thereto, whereby the tracking means and control means avoid draining electrical power from the storage battery.

11. A solar lighting apparatus as recited by claim 10 wherein the first and second photovoltaic panels are mounted to the reflector means for rotation therewith to follow daily movement of the sun.

12. A solar lighting apparatus as recited by claim 10 wherein the electrical output of the second photovoltaic panel decreases at the end of each day as the sun sets, and wherein the control means is responsive to the decreased electrical output of the second photovoltaic panel for operating the drive motor to rotate the base and the reflector means toward the east to face the sun on the following morning.

13. A solar lighting reflector apparatus for illuminating the interior of a roofed building during daylight hours and adapted to follow daily movements of the sun, the roofed building having a light transmissive opening in the roof therein, said apparatus comprising in combination:

a. a base;

b. means for rotatably supporting the base above the light transmissive opening of the roofed building;

c. reflector means secured to the base for rotation therewith, the reflector means reflecting solar light into the light transmissive opening;

d. a drive motor for rotating the base and the reflector means along therewith;

e. first photodetector means for generating a track signal when the first photodetector means receives a first predetermined amount of light;

f. second photodetector means for generating a stop signal when the second photodetector means receives a second predetermined amount of light;

g. the first and second photodetector means being supported for rotation with the reflector means and being positioned to generally face the sun when the reflector means is directed toward the sun;

h. a shade extending at least partially in front of the first and second photodetector means for shading direct rays of sunlight from the first and second photodetector means when the reflector means is directed toward the sun, the shade permitting sunlight to illuminate the first photodetector means when the reflector means is directed to the east of the current position of the sun, the shade permitting sunlight to illuminate the second photodetector means when the reflector means is directed to the west of the current position of the sun, the shade further permitting diffused sunlight under cloudy-bright conditions to illuminate both the first photodetector means and the second photodetector means; and

i. control circuitry for selectively applying electrical power to the drive motor for rotating the reflector means toward the west, the control circuitry being responsive to the presence of the track signal combined with the absence of the stop signal for enabling the drive motor to rotate the reflector means toward the west, the control circuitry being responsive to the presence of the stop signal for disabling the drive motor even when the track signal is present, to prevent false tracking under cloudy-bright conditions.

14. A solar lighting reflector apparatus as recited by claim 13 further including a third photodetector means for generating a seek signal when the third photodetector means receives a third predetermined amount of light, the third photodetector means being supported for rotation with the reflector means and being positioned to face generally away from the sun when the reflector means is directed toward the sun;

and wherein said control circuitry is responsive to the presence of the seek signal combined with the absence of the stop signal for enabling the drive motor to rotate the reflector means toward the west to seek out the sun following extended hours of overcast conditions.

15. A solar lighting reflector apparatus as recited by claim 13 further including a photovoltaic panel electrically coupled to the control circuitry for supplying electrical power thereto, the electrical output of the photovoltaic panel decreasing at the end of each day as the sun sets, and wherein the control circuitry is responsive to the decreased electrical output of the photovoltaic panel for operating the drive motor to rotate the reflector means toward the east to face the sun on the following morning.

16. A solar lighting reflector apparatus for illuminating the interior of a roofed building during daylight hours and adapted to follow daily movements of the sun, the roofed building having a light transmissive opening in the roof therein, said apparatus comprising in combination:

a. a base;

b. means for rotatably supporting the base above the light transmissive opening of the roofed building;

c. reflector means secured to the base for rotation therewith, the reflector means reflecting solar light into the light transmissive opening;

d. a drive motor for rotating the base and the reflector means along therewith;

e. first photodetector means for generating a track signal when the first photodetector means receives a first predetermined amount of light;

f. the first photodetector means being supported for rotation with the reflector means and being positioned to generally face the sun when the reflector means is directed toward the sun;

g. a shade extending at least partially in front of the first photodetector means for shading direct rays of sunlight from the first photodetector means when the reflector means is directed toward the sun, the shade permitting sunlight to illuminate the first photodetector means when the reflector means is directed to the east of the current position of the sun;

h. a second photodetector means for generating a seek signal when the second photodetector means receives a second predetermined amount of light, the second photodetector means being supported for rotation with the reflector means and being positioned to face generally away from the sun when the reflector means is directed toward the sun; and

i. control circuitry for selectively applying electrical power to the drive motor for rotating the reflector means toward the west when either the track signal is present or the seek signal is present to seek out the sun following extended hours of overcast conditions.

17. A solar lighting reflector apparatus as recited by claim 16 further including a photovoltaic panel for generating electrical power to operate the control circuitry, the electrical output of the photovoltaic panel decreasing at the end of each day as the sun sets, and wherein the control circuitry is responsive to the decreased electrical output of the photovoltaic panel for operating the drive motor to rotate the reflector means toward the east to face the sun on the following morning.