Self-contained solar tracking device

• US 4,226,502 A
• Filed: 07/24/1978
• Issued: 10/07/1980
• Est. Priority Date: 07/24/1978
• Status: Expired due to Term

• Current Assignee: Thomas Gunzler
• Original Assignee: Thomas Gunzler
• Inventors: Gunzler, Thomas
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US05/927,349
• Time in Patent Office: 806 Days
• Field of Search: 350/83, 353/3, 126/270, 126/271, 126/425
• US Class Current: 126/574
• CPC Class Codes: F24S 23/74 with trough-shaped or cylindro-parabolic reflective surfaces
• CPC Class Codes: F24S 23/77 with flat reflective plates
• CPC Class Codes: F24S 30/455 Horizontal primary axis
• CPC Class Codes: F24S 50/20 for tracking
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 10/47 Mountings or tracking

Abstract

A trough type solar collector or other body is mounted to rotate about a generally north-south pivotal axis. A balance weight is supported on an elongated heat sensitive beam anchored at its ends to the westerly side of the collector. The beam is adapted to bow away from the collector when it is heated by the sun'"'"'s rays, thereby causing the balance weight to exert westward rotational force on the collector. A reflector may be positioned behind the beam to concentrate the sun'"'"'s rays on the beam. A shutter is fixed to the collector to shade the beam when the collector is pointing toward the sun. Biasing means, such as a fixed weight secured to the easterly side of the collector, oppose the torque exerted by the balance weight and urge the collector to rotate eastwardly when the beam is unbowed. Damping means control the speed of westward and eastward rotation of the collector, and a pair of stops limit its westward and eastward travel. Alternative forms of heat sensitive support means for the balance weight and biasing means are shown and described. The motion of the solar tracking body can be utilized to control the orientation of other structures, such as adjustable louvres, with respect to the diurnal motion of the sun.

Claims

1. In an apparatus including a passive body having a predetermined generally north-south oriented tracking plane associated therewith, said body being suspended for rotation about a primary pivotal axis lying in said tracking plane in close proximity to the center of mass of said body and inclined with respect to the local gravitational vector, self-contained, self-regulating solar energy-operated tracking means for rotating said body about said axis and maintaining said tracking plane in substantially continuous alignment with the apparent instantaneous position of the sun during successive diurnal transits thereof, said tracking means comprising:

at least one balance mass movably attached to said body and reciprocable between a first limit position and a second limit position spaced from said tracking plane and lying in a control plane containing said primary pivotal axis and oriented substantially orthogonally to said tracking plane;

heat-sensitive primary positioning means acting on said balance mass and moving said balance mass between said first and second limit positions in response to direct solar radiation impinging on said primary positioning means; and

shielding means associated with said body, alternatingly shielding said primary positioning means from direct solar radiation when said tracking plane is substantially aligned with the apparent instantaneous position of the sun, and exposing said primary positioning means to direct solar radiation when said tracking plane is not so aligned, whereby said body is urged to rotate about said primary pivotal axis in the direction of the apparent diurnal motion of the sun.

2. The tracking means of claim 1, further comprising stop means associated with said body, limiting the rotation of said body and thereby preventing the alignment of said control plane with the local gravitational vector.

3. The tracking means of claim 2, further comprising damping means associated with said body controlling the rotational velocity of said body about said primary pivotal axis.

4. The tracking means of claim 3, further comprising bias mass attached to said body and spaced from said primary pivotal axis, said bias mass opposing said balance mass and predisposing the alignment of said tracking plane with the apparent instantaneous position of the rising sun.

5. The tracking means of claim 4, wherein said primary positioning means comprises:

a buckling column having said balance mass affixed thereto; and

rigid spaced support means affixed to said body and supporting said buckling column for buckling movement between said first and second limit positions in response to direct solar radiation impinging thereon.

6. The tracking means of claim 4, wherein said primary positioning means comprises:

a heat-sensitive bimetallic beam having said balance mass affixed thereto, and

rigid spaced support means affixed to said body and supporting said bimetallic beam for bending movement between said first and second limit positions in response to direct solar radiation impinging thereon.

7. The tracking means of claim 4, wherein said primary positioning means comprises at least one heat sensitive expansion beam affixed at one of its ends to said body, extending laterally of said body substantially orthogonally to said primary pivotal axis, and having said balance mass affixed thereto.

8. The tracking means of claim 4, wherein:

said primary positioning means comprises an hydraulic cylinder affixed to said body substantially orthogonally of said primary pivotal axis, at least one sealed pressure vessel containing a fluid under pressure, and a fluid conduit connecting said cylinder with said pressure vessel and maintaining said fluid in continuous communication with said cylinder;

said balance mass comprises a piston freely reciprocable in said cylinder between said first and second limit positions, said piston being urged toward one of said limit positions in response to an increase in the pressure acting on the fluid in said pressure vessel;

bias means associated with said cylinder urge said piston toward the other of said limit positions; and

said shielding means is positioned to expose said pressure vessel to solar radiation and thereby increase pressure within the pressure vessel acting on the fluid therein, when said tracking plane is out of alignment with the apparent instantaneous position of the sun, and to shield said pressure vessel from solar radiation and thereby reduce the said pressure therein, when said tracking plane is in substantial alignment with the apparent instantaneous position of the sun.

9. The tracking means of claim 8, wherein said fluid is a volatile liquid.

10. The tracking means of claim 8, wherein:

said piston defines first and second fluid-tight chambers within said cylinder on opposite sides of said piston, respectively;

said one pressure vessel is connected to one of said fluid-tight chambers;

said bias means comprises a second sealed pressure vessel containing fluid under pressure and connected with the other of said fluid-tight chambers by means of a second fluid conduit whereby the fluid in said second pressure vessel is maintained in continuous communication with the said other of said fluid-tight chambers; and

said shielding means is positioned to shield said second pressure vessel from solar radiation, when said tracking plane is in substantial alignment with the apparent instantaneous position of the sun.

11. In combination with a passive body having a predetermined generally north-south oriented tracking plane associated therewith, said body being suspended for rotation about a primary pivotal axis lying in said tracking plane in close proximity to the center of mass of said body and inclined with respect to the local gravitational vector,

self-contained, self-regulating solar energy-operated tracking means for rotating said body about said axis and maintaining said tracking plane in substantially continuous alignment with the apparent instantaneous position of the sun during successive diurnal transits thereof, said tracking means comprising:

at least one balance mass movably attached to said body and reciprocable between a first limit position and a second limit position spaced from said tracking plane; and

lying in a control plane containing said primary pivotal axis and oriented substantially orthogonally to said tracking plane;

heat-sensitive primary positioning means acting on said balance mass and moving said balance mass between said first and second limit positions in response to direct solar radiation impinging on said primary positioning means; and

shielding means associated with said body, alternatingly shielding said primary positioning means from direct solar radiation when said tracking plane is substantially aligned with the apparent instantaneous position of the sun, and exposing said primary positioning means to direct solar radiation when said tracking plane is not so aligned, whereby said body is urged to rotate about said primary pivotal axis in the direction of the apparent diurnal motion of the sun.

12. The combination of claim 11, further comprising stop means associated with said body, limiting the rotation of said body and thereby preventing the alignment of said control plane with the local gravitational vector.

13. The combination of claim 12, further comprising damping means associated with said body controlling the rotational velocity of said body about said primary pivotal axis.

14. The combination of claim 13, comprising a bias mass attached to said body and spaced from said primary pivotal axis, said bias mass opposing said balance mass and predisposing the alignment of said tracking plane with the apparent instantaneous position of the rising sun.

15. The combination of claim 14, wherein said primary positioning means comprises:

a buckling column having said balance mass affixed thereto; and

rigid spaced support means affixed to said body and supporting said buckling column for buckling movement between said first and second limit positions in response to direct solar radiation impinging thereon.

16. The combination of claim 14, wherein said primary positioning means comprises:

a heat-sensitive bimetallic beam having said balance mass affixed thereto; and

rigid spaced support means affixed to said body and supporting said bimetallic beam for bending moveement between said first and second limit positions in response to direct solar radiation impinging thereon.

17. The combination of claim 14, wherein said primary positioning means comprises at least one heat sensitive expansion beam affixed at one of its ends to said body, extending laterally of said body substantially orthogonally to said primary pivotal axis, and having said balance mass affixed thereto.

18. The combination of claim 14, wherein:

said primary positioning means comprises an hydraulic cylinder affixed to said body substantially orthogonally of said primary pivotal axis, at least one sealed pressure vessel containing a fluid under pressure, and a fluid conduit connecting said cylinder with said pressure vessel and maintaining said fluid in continuous communication with said cylinder;

said balance mass comprises a piston freely reciprocable in said cylinder between said first and second limit positions, said piston being urged toward one of said limit positions in response to an increase in the pressure acting on the fluid in said pressure vessel;

bias means associated with said cylinder urge said piston toward the other of said limit positions; and

said shielding means is positioned to expose said pressure vessel to solar radiation and thereby increase pressure within the pressure vessel acting on the fluid therein, when said tracking plane is out of alignment with the apparent instantaneous position of the sun, and to shield said pressure vessel from solar radiation and thereby reduce the said pressure therein, when said tracking plane is in substantial alignment with the apparent instantaneous position of the sun.

19. The combination of claim 18, wherein said fluid is a volatile liquid.

20. The combination of claim 18, wherein:

said piston defines first and second fluid-tight chambers within said cylinder on opposite sides of said piston, respectively;

said one pressure vessel is connected to one of said fluid-tight chambers;

said bias means comprises a second sealed pressure vessel containing fluid under pressure and connected with the other of said fluid-tight chambers by means of a second fluid conduit whereby the fluid in said second pressure vessel is maintained in continuous communication with the said other of said fluid-tight chambers; and

said shielding means is positioned to shield said second pressure vessel from solar radiation, when said tracking plane is in substantial alignment with the apparent instantaneous position of the sun.

21. In combination with a passive body having a predetermined tracking line of sight associated therewith, said body being suspended for rotation about a primary pivotal axis passing through said tracking line of sight, substantially orthogonal thereto, in close proximity to the center of mass of said body and inclined with respect to the local gravitational vector, and being further suspended for rotation about a secondary pivotal axis passing through said tracking line of sight, substantially orthogonal to said axis and to said primary pivotal axis, in close proximity to the center of mass of said body and inclined with respect to the local gravitational vector,

self-contained, self-regulating solar energy-operated tracking means for rotating said body about said primary and secondary pivotal axes and maintaining said tracking line of sight in substantially continuous alignment with the apparent instantaneous position of the sun during successive diurnal transits thereof throughout the solar ecliptic, said tracking means comprising:

at least one balance mass movably attached to said body and reciprocable between a first limit position and a second limit position spaced from said primary pivotal axis;

at least one other balance mass movably attached to said body and reciprocable between a first limit position and a second limit position spaced from said secondary pivotal axis;

heat sensitive primary positioning means acting on said balance masses and moving said balance masses between their said first and second limit positions in response to direct solar radiation impinging on said primary positioning means; and

shielding means associated with said body, alternatingly shielding said primary positioning means from direct solar radiation when said tracking line of sight is substantially aligned with the apparent instantaneous position of the sun, and exposing primary positioning means to direct solar radiation when said tracking line of sight is not so aligned, whereby said body is urged to rotate about said primary and secondary pivotal axes in the direction of the apparent diurnal motion of the sun throughout the solar ecliptic.

22. The combination of claim 21, comprising a bias mass attached to said body and spaced from said primary pivotal axis, said bias mass opposing said balance masses and predisposing the alignment of said tracking line of sight with the apparent instantaneous position of the rising sun.

23. The combination of claim 22, wherein said primary positioning means comprise

a pair of buckling columns having said balance masses affixed thereto, respectively;

and

rigid spaced support means affixed to said body and supporting said buckling columns for buckling movement between their said respective first and second limit positions in response to direct solar radiation impinging thereon.

24. In an apparatus including a passive body having a predetermined generally north-south oriented tracking plane associated therewith, said body being suspended for rotation about a primary pivot axis lying in said tracking plane in close proximity to the center of mass of said body and inclined with respect to the local gravitational vector, self-contained, self-regulating solar energy-operated tracking means for rotating said body about said axis and maintaining said tracking plane in substantially continuous alignment with the apparent instantaneous position of the sun during successive diurnal transits thereof, said tracking means comprising:

at least one solid balance mass movably attached to said body and reciprocable between a first limit position and a second limit position spaced from said tracking plane;

heat-sensitive primary positioning means acting on said balance mass and moving said balance mass between said first and second limit positions in response to direct solar radiating impinging on said primary positioning means; and

shielding means associated with said body, alternatingly shielding said primary positioning means from direct solar radiation when said tracking plane is substantially aligned with the apparent instantaneous position of the sun, and exposing said primary positioning means to direct solar radiation when said tracking plane is not so aligned, whereby said body is urged to rotate about said primary pivotal axis in the direction of the apparent diurnal motion of the sun.

25. The tracking means of claim 24, wherein said first and second limit positions lie in a control plane oriented substantially orthogonally to said tracking plane.

26. The tracking means of claim 25, wherein said control plane is proximate to and parallel with said primary pivotal axis.

27. In combination with a passive body having a predetermined generally north-south oriented tracking plane associated therewith, said body being suspended for rotation about a primary pivotal axis lying in said tracking plane in close proximity to the center of mass of said body and inclined with respect to the local gravitational vector,

self-contained, self-regulating solar energy-operated tracking means for rotating said body about said axis and maintaining said tracking plane in substantially continuous alignment with the apparent instantaneous position of the sun during successive diurnal transits thereof, said tracking means comprising:

at least one solid balance mass movably attached to said body and reciprocable between a first limit position and a second limit position spaced from said tracking plane;

heat-sensitive primary positioning means acting on said balance mass and moving said balance mass between said first and second limit positions in response to direct solar radiation impinging on said primary positioning means; and

shielding means associated with said body, alternatingly shielding said primary positioning means from direct solar radiation when said tracking plane is substantially aligned with the apparent instantaneous position of the sun, and exposing said primary positioning means to direct solar radiating when said tracking plane is not so aligned, whereby said body is urged to rotate about said primary pivotal axis in the direction of the apparent diurnal motion of the sun.

28. The combination of claim 27, wherein said first and second limit positions lie in a control plane oriented substantially orthogonally to said tracking plane.

29. The combination of claim 28 wherein said control plane is proximate to and parallel with said primary pivotal axis.