U.S. patent application number 10/458917 was filed with the patent office on 2003-10-30 for conversion of solar energy.
Invention is credited to Lawheed, Paul.
Application Number | 20030201008 10/458917 |
Document ID | / |
Family ID | 25349309 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030201008 |
Kind Code |
A1 |
Lawheed, Paul |
October 30, 2003 |
Conversion of solar energy
Abstract
An array of elongated concave parabolic trough-shaped reflectors
is disclosed. The orientation of the array is biaxially kept
essentially perpendicular to rays of the sun by an optical control
such that sunlight is reflected and concentrated along a focal line
of each elongated reflector by which (a) water in a tube disposed
at the focal line is heated by reflected line focused sunlight
impinged thereon and/or (b) line focused reflected sunlight is
optically transformed into point focused reflected sunlight using
Fresnel lenses from which electricity is generated using solar
cells upon which the point focused reflected sunlight is
impinged.
Inventors: |
Lawheed, Paul; (San Diego,
CA) |
Correspondence
Address: |
Mr. Lynn G. Foster
602 E. 300 S.
Salt Lake City
UT
84102
US
|
Family ID: |
25349309 |
Appl. No.: |
10/458917 |
Filed: |
June 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10458917 |
Jun 10, 2003 |
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10251709 |
Sep 21, 2002 |
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10251709 |
Sep 21, 2002 |
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09867196 |
May 29, 2001 |
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6498290 |
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Current U.S.
Class: |
136/246 |
Current CPC
Class: |
F24S 23/74 20180501;
Y02E 10/52 20130101; F24S 25/10 20180501; F24S 30/452 20180501;
F24S 2030/135 20180501; H02S 20/32 20141201; H01L 31/0547 20141201;
Y02B 10/10 20130101; H02S 40/44 20141201; F24S 2030/133 20180501;
Y10S 136/291 20130101; F24S 2030/136 20180501; Y02E 10/47 20130101;
Y02B 10/20 20130101; Y02E 10/60 20130101; Y02E 10/40 20130101; F24S
2030/131 20180501; F24S 50/20 20180501; F24S 23/31 20180501 |
Class at
Publication: |
136/246 |
International
Class: |
H01L 025/00 |
Claims
What is claimed and desired to be secured by Letters Patent is:
1. A method of transforming solar energy to thermal energy
comprising the acts of: (a) impinging rays of sunshine upon an
array of linear line-focusing parabolic trough reflectors arranged
in series and parallel; (b) mechanically tilting the reflectors
around at least one essentially horizontal axis and mechanically
turning the reflectors collectively along a curved track in respect
to an essentially vertical axis so that the reflectors individually
and collectively are essentially perpendicular to the rays of
sunshine; (c) correcting the tilt of the reflectors and the track
positions of the reflectors around the essentially horizontal axis
and the essentially vertical axis, respectively, to retain said
perpendicular relationship; (d) heating influent water in a tube
with reflected sunlight at a focal line of each reflector; (e)
discharging the tube-heated water as effluent for subsequent
use.
2. A method according to claim 1 wherein the mechanically tilting
and the correcting the tilt acts comprise collectively tilting and
correcting the tilt of all reflectors.
3. A method according to claim 1 wherein the mechanically tilting
act takes place around a plurality of parallel essentially
horizontal axes.
4. A method according to claim 1 wherein the collectively turning
act takes place along a circular track.
5. A method of transforming solar energy to electrical energy
comprising the acts of: (a) impinging rays of sunshine upon an
array of line-focusing parabolic trough reflectors; (b)
mechanically and collectively tilting the reflectors in respect to
at least one essentially horizontal axis and mechanically and
collectively turning the reflectors along a curved track in respect
to an essentially vertical axis; (c) position-correcting the tilt
and track orientations of the reflectors collectively to retain
said essentially perpendicular relationship; (d) transforming
reflected sunlight to electrical energy along a focal line of each
reflector; (e) communicating the electrical energy for use.
6. A method according to claim 5 wherein the transforming act
comprises changing the line focus of reflected sunlight to a series
of focal points sites and imposing the point focused reflected
sunlight upon a series of solar cells at said sites.
7. A method according to claim 6 wherein the changing act comprises
passing the line focused reflected sunlight through a series of
Fresnel lenses.
8. A method according to claim 6 wherein the imposing act is
preceded by further reflecting stray sunlight passing through the
Fresnel lens from at least one converging surface onto each solar
cell.
9. A method according to claim 5 wherein the transforming act
comprises point focusing reflected sunlight at the focal line of
each reflector upon a solar cell and outputting said electrical
energy from each solar cell.
10. A method according to claim 9 wherein the point focusing is
achieved by passing the line focused sunlight through a lineal
series of Fresnel lens.
11. A method according to claim 9 wherein the point focusing is
achieved by passing the line focused sunlight through a series of
Fresnel lens and concentrating the sunlight output from each
Fresnel lens upon an associated solar cell with a funnel-shaped
reflector peripherally disposed around the solar cell.
12. A method of converting solar energy to at least one other form
of energy comprising the acts of: progressively and collectively
turning and tilting an array of parabolic trough reflectors to
maintain an essentially perpendicular relationship between rays of
sunlight and the reflectors while converting reflected sunlight
concentrated along focal lines of the reflectors to at least one
other form of energy selected from the group consisting of thermal
energy and electrical energy.
13. A method according to claim 12 wherein the converting step
comprises heating tube-contained water at each focal line with the
reflected sunlight.
14. A method according to claim 12 wherein the converting step
comprises transforming reflected line focused sunlight to point
focused reflected sunlight at spaced locations along the focal
lines and imposing the point focused reflected sunlight upon solar
cells at said spaced locations to create electricity.
15. A method according to claim 12 wherein the converting step
comprises heating tube-contained water along some of the focal
lines and energizing solar cells adjacent other focal lines to
create electricity.
16. A method according to claim 12 wherein the converting step
comprises point focusing reflected line focused sunlight at a
plurality of locations upon linearly spaced solar cells to create
electricity.
17. A method according to claim 12 wherein the converting step
comprises heating tube-contained water with line focused reflected
sunlight along some of the focal lines and point focusing reflected
line focused sunlight at other focal lines upon solar cells to
create electricity.
18. A method of converting solar energy to at least one other form
of energy comprising the acts of: positioning an assembly of
reflectors so that each reflector is essentially perpendicular to
rays of sunlight; reflecting the sunlight from each reflector so as
to focus the sunlight in concentrated form along a focal line;
converting the line focused reflected sunlight to at least one
other form of energy selected from the group consisting of thermal
energy, electrical energy and both.
19. A method according to claim 18 wherein the converting act
comprises heating water in a tube with the reflected line focused
sunlight along at least one of the focal lines.
20. A method according to claim 18 wherein the converting act
comprises refracting reflected line focused sunlight into point
focused sunlight at at least one of the focal lines and imposing
the point focused sunlight upon a plurality of solar cells near
other focal lines to create electricity.
21. A method according to claim 18 wherein the reflecting act is
achieved using an assembly of parabolic trough reflectors.
22. A method according to claim 18 wherein the positioning act
comprises continuously sensing the location of the sun and
bidirectionally altering the orientation of the reflectors
progressively as the relative location of the sun changes to
maintain said essentially perpendicular relationship.
23. A method according to claim 22 wherein the sensing act is
optical and the altering act is electro-mechanical.
24. A method according to claim 18 further comprising the acts of
mounting the assembly of reflectors upon an upper frame for pivotal
movement in respect to spaced parallel essentially horizontal axes
and rotatably mounting the upper frame upon a lower frame having an
essentially vertical axis and wherein the positioning act comprises
pivoting the reflectors essentially in unison around the
essentially horizontal axes and rotating the upper frame about the
essentially vertical axis to follow the sun.
25. A method according to claim 24 wherein the positioning act
comprises continually optically sensing the ever changing relative
location of the sun to generate control signals by which at least
one power mechanism pivotally adjusts the positions of the
reflectors around the essentially horizontal axes and by which at
least one other power mechanism rotates the upper frame in respect
to the lower frame around the essentially vertical axis to thereby
continuously maintain the perpendicular relationship.
26. A method according to claim 24 wherein the positioning act
comprises continually optically sensing the ever changing relative
location of the sun to generate control signals by which a first
motor-driven actuator pivots the reflectors around the essentially
horizontal axes and by which a second motor driven actuator rotates
the upper frame in respect to the lower frame around the
essentially vertical axis to thereby continuously maintain the
perpendicular relationship.
27. A method according to claim 26 wherein the first motor-driven
actuator comprises a screw displacement device and the second motor
driven actuator comprises a drive mechanism selected from the group
consisting of a sprocket and chain drive and a pulley and cable
drive.
28. A method according to claim 18 wherein the positioning act
comprises (a) collectively altering the inclined disposition of the
reflectors with respect to the vertical using a first displacement
system and (b) collectively turning the reflectors in respect to
the horizontal using a second displacement system.
29. A method according to claim 18 wherein the positioning act is
preceded by the act of mounting the reflectors upon an upper frame
rotationally supported upon a lower static frame, the lower static
frame being supported by structure selected frame the group
consisting of ground-engaging columns, roof-engaging columns and
non-column support structure.
30. A method according to claim 18 wherein the converting act
comprises transforming line focused reflected sunlight into point
focused reflected sunlight by imposing the line focused upon light
concentrators selected from the group consisting of Fresnel lenses
and convergently tapered secondary reflectors to produce point
focused sunlight, and solar cell upon which the point focused
sunlight is impinged for production of electricity.
31. A method according to claim 18 wherein the positioning act
comprises optically determining the location of the sun and
electro-mechanically bidirectionally bringing the reflectors into
essentially perpendicular relationship with the rays of
sunlight.
32. A method according to claim 18 wherein the converting act heats
water in tubes at lines of focus and further comprises insulating
the tubes at locations not aligned with the rays of sunlight.
33. A method according to claim 18 wherein the converting act
produces DC electricity which is directly used, stored and/or
changed into AC electricity.
34. An apparatus for transforming solar energy to thermal energy
comprising: (a) an array of linear line-focusing angularly
adjustable parabolic trough reflectors arranged in series and
parallel; (b) an upper frame supporting the array of angularly
adjustable parabolic trough reflectors; (c) a lower frame rotatably
supporting the upper frame upon a track; (d) a control system for
collectively adjusting the angularity of each parabolic trough
reflector and for curvilinearly displacing the upper frame along
the track upon the lower frame, to obtain and retain essentially
perpendicularity between rays of sunshine and the reflectors
whereby reach reflector reflects and focuses sunlight along a line;
(e) an energy converter located at at least one of the focus lines
by which reflected line focused sunlight is transformed into
thermal energy.
35. An apparatus according to claim 34 wherein the energy converter
comprises a tube containing water located at at least one of the
focus lines, which water is heated by the line focused reflected
sunlight.
36. An apparatus according to claim 35 further comprising external
insulation carried externally on the tube exclusive of where
reflected line focused sunlight impinges on the tube.
37. An apparatus according to claim 35 further comprising an
elongated housing at the focus line in which the tube is
disposed.
38. An apparatus according to claim 37 wherein the housing
comprises a window through which line focused reflected sunlight
passes prior to being impinged upon the tube.
39. An apparatus according to claim 34 wherein the track comprises
a curvilinear I-beam comprising an upper flange, a lower flange and
a web and the upper housing comprises I-beam followers.
40. An apparatus according to claim 39 wherein the I-beam followers
each comprise first rollers rotatably in contact with the lower
flange of the I-beam to accommodate rotation of the upper frame in
respect to the lower frame and second rollers in contact with the
web of the I-beam to prevent the upper frame from jumping the
track.
41. An apparatus according to claim 40 wherein the first and second
rollers of each I-beam follower are rotatably carried by at least
one carriage of the upper frame.
42. An apparatus according to claim 41 wherein the carriage
comprises a trunnion.
43. An apparatus according to claim 34 wherein the reflectors are
gang connected together in series and in parallel.
44. An apparatus according to claim 34 wherein the control system
comprises at least one displaceable toggle mechanism connected to
the reflectors and selectively motor actuated for displacing the
toggle mechanism to achieve said angularity to thereby achieve and
maintain said perpendicularity.
45. An apparatus according to claim 34 wherein the control system
comprises a motor-driven displacement mechanism by which the upper
frame is turned relative to the lower frame upon the track to
achieve and maintain said perpendicularity.
46. An apparatus according to claim 34 wherein the control system
comprises at least one rotatable torque tube connected to the
reflectors and selectively motor rotated for achieving said
angularity to thereby achieve and maintain said
perpendicularity.
47. An apparatus for transforming solar energy to electrical energy
comprising the acts of: (a) an array of line-focusing angularly
adjustable parabolic trough reflectors upon which sunlight is
impinged and reflected; (b) an upper frame supporting the array of
angularly adjustable parabolic trough reflectors; (c) a lower frame
rotatably supporting the upper frame upon a track; (d) a control
system or collectively adjusting the angularity of each parabolic
trough reflector and for rotating the upper frame along the track
of the lower frame, to obtain and retain essentially
perpendicularity between rays of sunshine and the reflectors
whereby reach reflector reflects and focuses sunlight along a line;
(e) an energy converter located at at least one of the focus lines
by which reflected line focused sunlight is transformed into
electrical energy.
48. An apparatus according to claim 47 wherein the energy converter
comprises a point focusing structure located at at least one of the
focus lines by which the line focused reflected sunlight is changed
to point focused reflected sunlight and a solar cell at the point
of focus by which point focused reflected sunlight is changed to
electrical energy.
49. An apparatus according to claim 48 wherein the point focusing
structure comprises a series of Fresnel lenses linearly arranged
along the focal line.
50. An apparatus according to claim 48 wherein the focusing
structure comprises light concentrators each having at least one
converging side wall surface and a throat, with the solar cell
disposed at the throat.
51. An apparatus according to claim 47 wherein the track comprises
a curvilinear I-beam comprising an upper flange, a lower flange and
a web and the upper housing comprises I-beam followers.
52. An apparatus according to claim 51 wherein the I-beam followers
each comprise first rollers rotatably in contact with the lower
flange of the I-beam to accommodate rotation of the upper frame in
respect to the lower frame and second rollers in contact with the
web of the I-beam to prevent the upper frame from jumping the
track.
53. An apparatus according to claim 52 wherein the first and second
rollers are rotatably carried by at least one carriage of the upper
frame.
54. An apparatus according to claim 53 wherein the carriage
comprises a trunnion.
55. An apparatus according to claim 50 wherein the reflectors are
gang connected together in series and in parallel.
56. An apparatus according to claim 47 wherein the control system
comprises at least one displaceable toggle mechanism connected to
the reflectors and selectively motor actuated for displacing the
toggle mechanism to achieve said angularity thereby to achieve and
maintain said perpendicularity.
57. An apparatus according to claim 47 wherein the control system
comprises a motor-driven displacement mechanism by which the upper
frame is turned relative to the lower frame upon the track to
achieve and maintain said perpendicularity.
58. An apparatus according to claim 47 wherein the control system
comprises at least one rotatable torque tube connected to the
reflectors and selectively motor rotated for achieving said
angularity to thereby achieve and maintain said
perpendicularity.
59. An apparatus for converting solar energy to at least one other
form of energy comprising: an array of parabolic trough reflectors;
a control system for maintaining an essentially perpendicular
relationship between rays of sunlight and the reflectors; an energy
converter for converting reflected sunlight concentrated along
focal lines of the reflectors to at least one other form of energy
selected from the group consisting of thermal energy and electrical
energy.
60. An apparatus according to claim 59 wherein the energy converter
comprises tube-contained water at at least some of the focal lines
whereby the line focused reflected sunlight heats the water.
61. An apparatus according to claim 59 wherein tie energy converter
comprises sunlight concentrators for transforming reflected line
focused sunlight to point focused reflected sunlight at spaced
locations along at least some of the focal lines and solar cells
adjacent to said spaced locations upon which point focused
reflected sunlight is impinged to create electricity.
62. An apparatus according to claim 59 wherein the energy converter
comprises: (a) tube contained water at at least some of the focal
lines whereby line focused reflected sunlight heats the water and
(b) sunlight concentrators at predetermined focal lines
transforming reflected line focused sunlight into point focused
reflected sunlight and a solar cell adjacent to each sunlight
concentrator upon which point focused reflected sunlight is
impinged to create electricity.
63. An apparatus for converting solar energy to at least one other
form of energy comprising the acts of: an assembly of reflectors; a
reflector control system so that each reflector is retained
essentially perpendicular to rays of sunlight and therefore
sunlight reflected from each reflector is concentrated along a
focal line; an energy converter for receiving and converting the
line focused reflected sunlight to at least one other form of
energy selected from the group consisting of thermal energy,
electrical energy and both.
64. An apparatus according to claim 63 wherein the energy converter
comprises a tube containing water upon which the reflected line
focused sunlight is impinged to heat the water.
65. An apparatus according to claim 63 wherein the energy converter
comprises refracting lenses by which reflected line focused
sunlight is changed into point focused sunlight at at least one of
the focal lines and a plurality of solar cells upon which the point
focused sunlight is impinged to create electricity.
66. An apparatus according to claim 63 wherein the control system
comprises at least one sensor continuously sensing the location of
the sun and at least one power displacement mechanism
bidirectionally altering the orientation of the reflectors
progressively as the relative location of the sun changes to
maintain said essentially perpendicular relationship.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to conversion of
sunlight into other forms of energy, including thermal energy and
electrical energy, and, more particularly, to use of elongated
concave trough-shaped reflectors connected in an array for unitary
movement, and maintaining essentially perpendicularity between the
reflectors and the rays of the sun to heat water with
linearly-focused, reflected sunlight and to create electricity with
point-focused reflected sunlight derived from the line-focused
reflected sunlight.
BACKGROUND
[0002] Solar energy is freely and daily available. It is a clean,
non-polluting source of energy. Providing a reliable, long term,
cost effective, efficient way of using sunlight to obtain
electrical and thermal power has long been an unsolved problem,
until the present invention.
[0003] It has been proposed that flat panel solar converters be
used to convert direct sunlight into thermal or electrical
energy.
[0004] Pedestal supported flat panels using direct sunlight to
generate electricity were part of the Solar One project.
[0005] A circular, but concave reflector mounted on a single column
or pedestal has been proposed. This approach was used on the
Soleras water desalination project in Saudi Arabia and on the Solar
Two project in Dagget, Calif.
[0006] Fixed position concave reflectors placed in an array and
positioned in side by side rows on an incline have ben proposed.
See U.S. Pat. No. 4,202,322. Such an installation was made at the
Federal Correctional institution at Phoenix, Ariz.
[0007] Tiltable elongated concave reflector assemblies have been
utilized, such as the one at Barstow, Calif., owned by FPL Energy
SEGS VIII and IX.
[0008] Solar Systems comprising bidirectionally controlled Fresnel
lens and solar cell assemblies, utilizing direct sunlight, have
been proposed. See, U.S. Pat. No. 4,649,899, for example. Also see,
U.S. Pat. No. 4,245,153. Optical detectors for dual axis tracking
of the sun are known.
[0009] The above-identified proposals and installations have failed
to provide reliable, low cost, efficient, variable capacity systems
by which solar energy is converted to thermal and/or electrical
energy. A long felt need has existed for energy conversion plants
which are reliable, efficient, cost effective and size variable to
meet both low and high capacity demands for thermal and electrical
energy.
BRIEF SUMMARY AND OBJECTS OF THE PRESENT INVENTION
[0010] In brief summary, the present invention overcomes or
substantially alleviates the long term problems of the prior art by
which solar energy is converted to thermal energy and/or electrical
energy. The present invention provides reliable, cost effective
systems for such conversion, where the size of the system can be
correlated to the desired capacity.
[0011] The orientation of an array of elongated concave parabolic
trough-shaped reflectors is biaxially kept essentially
perpendicular to rays of the sun by a control such that the
sunlight is reflected and concentrated along a focal line of each
elongated reflector by which (a) tube-contained water is heated at
the focal line by reflected sunlight impinged thereon and/or (b)
line focused reflected sunlight is optically transformed into point
focused reflected sunlight from which electricity is generated
using solar cells upon which the point focused reflected sunlight
is impinged.
[0012] With the foregoing in mind, it is a primary object of the
present invention to overcome or substantially alleviate the long
term problems of the prior art by which solar energy is converted
to thermal energy and/or electrical energy.
[0013] Another paramount object of the present invention is to
provide reliable, cost effective systems for such conversion, where
the size of any such system can be correlated to the desired
capacity.
[0014] A further object of great significance is the provision of
solar energy conversion systems wherein the orientation of an array
of elongated concave parabolic trough-shaped reflectors is
biaxially kept essentially perpendicular to rays of the sun by a
control such that the sunlight is reflected and concentrated along
a focal line of each elongated reflector by which (a)
tube-contained water is heated at the focal line by reflected
sunlight impinged thereon and/or (b) line focused reflected
sunlight is optically transformed into point focused reflected
sunlight from which electricity is generated using solar cells upon
which the point focused reflected sunlight is impinged.
[0015] These and other objects and features of the present
invention will be apparent from the detailed description taken with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective representation, schematic in nature
of one configuration embodying principles of the present
invention;
[0017] FIG. 2 is a perspective of one form of the stationary lower
frame forming a part of embodiments of the present invention;
[0018] FIG. 3 is a perspective representation of an upper frame
embodiment which is rotated optically to follow the sun, and
reflector frames, the tilt of which is adjustable in unison;
[0019] FIG. 4 is a diagrammatic representation of the manner in
which the attitude and azimuth of the array of parabolic
trough-shaped reflectors is displaced to maintain perpendicularity
with the sun and the manner in which line-focused reflected
sunlight is impinged upon a solar-to-thermal or
solar-to-electricity converter;
[0020] FIG. 5 is an enlarged fragmentary perspective of two
parabolic trough-shaped reflectors and reflector frames together
with energy converters disposed at the line focal point of each
reflector, each converter being supported by two cantilevered
structural members;
[0021] FIG. 6 is a fragmentary enlarged perspective of an optical
detector used to cause the upper frame, reflector frames and
reflectors to follow the sun in the sky so as to preserve
perpendicularity between the reflectors and the rays of the
sun;
[0022] FIG. 7 is a schematic representation of a system by which
line-focused reflected sunlight is converted to thermal energy;
[0023] FIG. 8 is a diagrammatic representation of the manner in
which point-focused reflected sunlight is converted to electrical
energy;
[0024] FIG. 9 is an elevational view, shown partly in cross
section, illustrated in the manner in which the tilt of the array
of reflectors is altered to maintain perpendicularity with the
sun;
[0025] FIG. 10 is a fragmentary perspective illustrating, in part,
the toggle mechanism by which the tilt of the array of reflectors
is changed to maintain perpendicularity with the rays of the
sun;
[0026] FIG. 11 is an enlarged fragmentary representation of the
toggle mechanism illustrated in FIG. 10 viewing the same from the
concave side of the reflectors as opposed to the convex side;
[0027] FIG. 12 is an enlarged fragmentary perspective similar to
FIG. 11 further illustrating the manner in which a screw drive is
motor displaced responsive to optical signals to change the tilt of
the array of reflectors to maintain the above-mentioned
perpendicularity;
[0028] FIG. 13 is an enlarged perspective illustrating the manner
in which the upper frame is displaced along a track of the lower to
maintain said perpendicularity;
[0029] FIG. 14 is cross section taken along lines 14-14 of FIG.
13;
[0030] FIG. 15 is a cross section taken along lines 15-15 of FIG.
13;
[0031] FIG. 16 is a fragmentary enlarged perspective representation
illustrating a portion of the upper, displaceable frame, the motor
and differential by which the upper frame is rotated selectively
upon the lower frame;
[0032] FIG. 17 is a fragmentary enlarged perspective illustrating
the motor and rotational drive system by which the upper frame is
rotated selectively upon the lower frame;
[0033] FIG. 18 is likewise an enlarged fragmentary perspective of
the rotational drive system by which the upper frame is rotated
selectively in respect to the lower frame for preserving
perpendicularity with the sun;
[0034] FIG. 19 is a cross sectional view taken along line 19-19 of
FIG. 2;
[0035] FIG. 20 is a fragmentary elevational view of an additional
form of the present invention comprising a lower static frame
supported upon columns and comprising a curved track upon which an
upper frame is mounted for selective rotational displacement;
[0036] FIG. 21 is a fragmentary plan view of a relatively large
embodiment of the present invention wherein the upper frame is
rotatably mounted upon two or more tracks;
[0037] FIG. 22 is a plan view of a torque tube drive which may be
used in lieu of a toggle mechanism when a large array of parabolic
reflectors is utilized;
[0038] FIG. 23 is a cross section taken along lines 23-23 of FIG.
22;
[0039] FIGS. 24 and 25 are cross sectional views illustrating the
manner in which a thermal converter disposed at the focal line of a
parabolic reflector may be insulated;
[0040] FIG. 26 is a perspective representation of an energy
converter adapted to be disposed at the focal line of a
trough-shaped parabolic reflector to convert solar energy to
electrical energy;
[0041] FIG. 27 is a plan view illustrating a different form of
secondary reflector to ensure point focus impingement of reflected
sunlight upon solar cells;
[0042] FIG. 28 is a cross sectional view taken along line 28-28 of
FIG. 27;
[0043] FIG. 29 is a fragmentary perspective of another reflector
embodiment with the support frame on the convex or back side of the
reflector; and
[0044] FIGS. 30, 31 and 32 are a cross section taken along lines
30-30, 31-31 and 32-32, respectively, of FIG. 29.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0045] The present invention utilizes the free and limitless energy
of the sun to produce electricity and thermal energy. The scale of
embodiments according to the present invention can be tailored to
the need, ranging from small stand alone systems for residential
and small business use to intermediate sized plants for plant or
factory use to massive assemblies design to mitigate against if not
eliminate the electrical energy crisis in California The present
photovoltaic invention is economical to install and maintain, is
reliable and not maintenance-intensive, is efficient and cost
effective to operate and does not pollute the environment. The sun
is not a consumable resource.
[0046] Using the present invention, businesses, industrial plants,
retail and office buildings, homes, farms and villages can produce
some, if not all, of their own electrical and thermal power, and
avoid the largest uncontrollable cost of doing business today--the
ever-escalating price of purchased power generated from fossil and
nuclear fuels.
[0047] This invention is capable of making significantly more
energy per square foot than conventional flat plate solar
collectors. And flat plate collectors are incapable of
co-generating the large amounts of thermal energy that the present
concentrating photovoltaic generating systems make
automatically.
[0048] Until now, remote installations have been faced with a
difficult choice: pay the prohibitive costs of bringing in utility
power, or depend on costly, noisy, and hard to maintain
pollution-creating diesel, gas or propane generators. The present
invention is a third and better choice, which can be scaled or
sized to produce as much electrical and/or thermal energy as
needed, independently, on site; the energy needed to power a home
or business, pump water, irrigate land and run remote communication
installations.
[0049] Unlike centralized forms of power generation, on-site
de-centralized use of solar power needs no far-flung distribution
network of gigantic towers and high voltage lines. Instead it
utilizes a universally available asset--sunshine. No moving parts,
except for the perpendicularity biaxial tracking system. It is
noiseless, pollution-free, and requires almost no maintenance over
many years of service.
[0050] Decentralized sunlight-derived electrical power can free
users from the effects of peak-hour brown-outs, and from the
possibility of total black-outs caused by operator error or the
planned actions of groups hostile to utilities or nations.
[0051] The cost of the generating equipment itself--through the
production of power for a building can be amortized over the life
of the building, as part of debt financing (mortgage). Amazing as
it may seem, one of the largest and most uncontrollable costs a
building owner faces is the ever-escalating cost of power. Using
the present invention, one actually has the ability to eliminate
most of the cost of purchased power now and for years to come.
[0052] When land and water were plentiful and labor was cheap,
little was known about the delicate balance existing between the
environment and the extraction, burning, and wastes of
non-renewable fuels. Now it is all too apparent that our supply of
fossil fuels is limited--and that these sources are causing damage
to our atmosphere, water supplies, and food chain--damage that is
or may soon become irreversible. The costs, too, for fossil fuels
continue upward as the more accessible fuel deposits are consumed,
and as the costs for machinery, labor, and transportation continue
to rise around the world.
[0053] Ironically, the best answer to the world's need for energy
has always been the sun. The sun can satisfy a significant
percentage of our energy requirements while helping us to become
independent of the negative aspects inherent in conventional power
generation. Switching to solar-derived power will reduce the
pollution produced by coal, oil and nuclear fuels. It will also
slow the use of oil and allow us to conserve it for more valuable
uses, such as chemical feedstocks and plastics. The rate of coal
usage would also be slowed. Harnessing the sun will also reduce, or
eliminate, the need for nuclear power and mitigate its many risks
and problems.
[0054] Even though the sun is just beginning to contribute to
satisfying the world's energy demands on a large scale, direct
sunlight has been powering satellites and spacecraft since 1958. In
the 1970's the first terrestrially-directed sunlight photovoltaics
supplied power to locations too remote to have ties to utility
lines. Then, as the solar industry developed more efficient silicon
cells and generators, larger grid-connected direct sunlight
installations became practical.
[0055] The present invention is not space-intensive. One embodiment
of the present invention can be mounted on an existing rooftop so
that it essentially takes up no additional space at all.
Ground-mounted systems on a pad or the like is also an option as
well. Column mounting is a further option.
[0056] Various embodiments of the present invention may be used in
conjunction with residences, office buildings, manufacturing
facilities, apartment buildings, schools, hospitals, remote
communications, telemetry facilities, offshore platforms, water
pumping stations, desalination systems, disinfection systems,
wilderness camping, headquarters installations, remote medical
facilities, refrigeration systems, farms and dairies, remote
villages, weather stations, and air conditioning systems, to name a
few.
[0057] The present invention is also useful in: (a) providing
cathodic protection against galvanite corrosion, (b) storage of
electrical energy in batteries and (c) generation and sale of
electricity to utility companies.
[0058] The sun is an energy source that, unlike fossil fuels, is
free each day to whatever generation site is selected. It does not
need to be mined, transported, refined, burned or purchased. So the
costs for all these steps to produce energy are eliminated. Gone,
too, are all forms of pollution. There are no particulates or gases
vented into the atmosphere. Nor is there a need for millions of
gallons of cooling water. (The small amount of water used to cool
the solar cells actually becomes a second form of co-generated
power, i.e. production of thermal energy, that has dozens of
residential and commercial uses.) So water is conserved. There are
no massive discharges of hot water into coastal waters to elevate
the normal temperature and alter and perhaps destroy the habitats
and food chains of coastal marine life. With solar energy, there
are no wastes of any kind to be removed or buried in mines or deep
at sea, so there are few, if any, health risks to our generation or
future generations.
[0059] Various embodiments of the invention are modular, allowing
any installation to be as large or as small to meet exactly the
needs of the installation for electrical and/or thermal energy. The
electricity produced is direct Current (DC), which, when
appropriate, may be transformed into alternating current (AC) using
an inverter or DC-to-AC converter.
[0060] At the heart of the present invention is the utilization of
a system which biaxially tracks the location of the sun in the sky
to maintain a perpendicularity between an array of parabolic
trough-shaped reflectors and the rays of the sun so that reflected
line or point focused sunlight may be efficiently converted into
thermal and/or electrical energy.
[0061] FIG. 1 is a diagrammatic representation of one configuration
or system according to the present invention, which system is
generally designated 40. System 40 comprises a lower stationary or
static frame 42, an upper rotatable frame 44, mounted for movement
upon the stationary frame 42, an array of parabolic trough-shaped
reflectors, generally designated 46, carried by the upper frame 44,
an optical sun-locating control, generally designated 48, carried
by the upper frame 44, a rotational drive mechanism, generally
designated 50, by which the upper frame 44 is rotated about the
lower frame 42 to maintain perpendicularity between the rays of the
sun and the reflective surfaces of the parabolic reflectors
comprising the array 46 under control of the optical sensor 48, a
toggle reflector-tilting mechanism, generally designated 52, by
which the angle of tilt of the parabolic reflectors of the array 46
is altered to maintain said perpendicularity as the sun travels
across the sky and energy converters 54, one being disposed along
the focal line of each parabolic reflector for converting
reflected, concentrated sunlight into thermal and/or electrical
energy.
[0062] An advantage of the present invention, when disposed in the
form of apparatus 40, is that it is modular, i.e. the number of
reflectors can vary, ranging from a relatively small number to a
relatively large number, depending upon the needs of a given
facility.
[0063] In the form shown in FIG. 1, the lower frame 42 comprises a
curvilinear, preferably circular, track, generally designated 56,
which, in cross section, is in the form of an I-beam comprising an
upper flange 58, a lower flange 60 and a web 62. The track 56 is
preferably made of steel and may be formed into the configuration
shown in FIG. 1 using roller technology available at a conventional
steel plant. The track 56 is supported upon a plurality of floor,
roof or ground-engaging legs 64. Legs 64 may be of any desirable
type. All or some of the legs 64 may be adjustable in length to
provide for leveling, as herein described in greater detail, or of
fixed length, where leveling is not a consideration in order to
place the track 56 in essentially a horizontal orientation. The leg
64 may be made of steel construction, or some other suitable
material may be used. Of course, the lower frame may be varied in
its construction from that illustrated in FIG. 1 without departing
from the spirit or essential characteristics of the present
invention, so long as a tracking of the sun and adequate capacity
are provided.
[0064] With continued reference to FIG. 1, the upper frame 44 is
shown schematically as comprising a rectangular member 66, formed
of hollow bar stock which is rectangular in cross section, for
example, with interconnecting cross members 68 integrally joined at
the ends thereof to the rectangular member 66, as by welding or use
of conventional connectors comprising, for example, screw or nut
and bolt fasteners. Upper frame 44, as illustrated in FIG. 1, is
intended to be fundamentally diagrammatic, to illustrate principles
associated with the present invention.
[0065] While not shown in detail in FIG. 1, the upper frame 44 is
rotatably associated with the lower fixed frame 42 in such a way,
for example, that rollers traverse the track 56 to and fro for the
purpose of maintaining perpendicular azimuth alignment between the
rays of the sun and the disposition of each reflectors 46 of the
array. Rotational displacement of the upper frame 44 in respect to
the lower frame 42, in this regard, is achieved by the motor and
rotational drive assembly 50, responsive to signals from the
optical detector 48, as explained herein in greater detail. The
optical detector 48 is illustrated and is being mounted to a
reflector frame associated with one of the reflectors 76, at site
70, in FIG. 1.
[0066] The toggle tilting mechanism comprises a motor-driven,
reversible screw jack 72, the proximal cylinder end of which is
connected to the upper frame 44 and the exposed distal piston end
74 thereof is pivotally connected at site 78 to one or more
reflector frame members which support the assemblage or array of
reflectors 76 for unitary variation in tilting to maintain altitude
perpendicularity with the sun. As the piston rod 74 is extended and
retracted, the reflectors 76 are tilted in unison by a toggle
mechanism 80. The tilting mechanism 52 and toggle mechanism 80 are
illustrated diagrammatically in FIG. 1. Each reflector 76 in a line
or tandem of reflectors is non-rotatably connected to one or two
adjacent reflectors by structural members 83 which accommodate the
above-mentioned unitary tilting of the reflectors.
[0067] From the foregoing, it is clear that the upper frame 44 is,
selectively rotated upon lower frame 42 pursuant to optical control
signals and the trough-shaped parallel reflectors 76 are adjusted
in the angularity of their tilt, so that each reflector 76 is
essentially perpendicular to the rays of the sun at all times
during daylight hours. It is the use of reflected line and point
focused sunlight that significantly distinguishes the present
invention.
[0068] With reference to FIG. 2, a somewhat modified lower frame
42' is illustrated. This embodiment illustrates the previously
described circular track 56. A drive chain 90 rests upon the lower
flange 60 of the erect I-beam track 56 to accommodate selective
rotation of the upper frame in respect to the lower frame 42' in
the manner explained above. In lieu of leg 64, telescopic legs,
generally designated 64', are provided. Each leg 64' is illustrated
as comprising sequential aligned leg segments 92 and 94 which are
telescopically interrelated so that the overall length may be
adjusted to level the track 56. To do this, a set screw 96 is
loosened, the correct collective length for the leg segments 92 and
94 established and the set screw 96 threadedly tightened through
the leg segment 92 against the leg segment 94 to maintain the
desired collective length. For added structural load-transferring
stability, diagonal braces 98 are provided. The top of tube 92 and
the top of each brace 94 is welded or otherwise suitably secured to
the underside of lower track flange 60. The lower end of each
diagonal brace 98 is welded or otherwise suitably secured to the
associated tube 92.
[0069] The lower end of each tube 94 is illustrated as being welded
to a plate or pedestal 100, which may be apertured so as to receive
nut and bolt assemblies 102, with the lower heads thereof being
imbedded in concrete for stability.
[0070] With reference to FIG. 3, one type of suitable upper frame,
generally designated 44', is shown, which implements principles of
the present invention. The upper frame 44' is superimposed upon the
circular track 56 and supports aligned pairs of reflector frames,
each generally designated 110, by which the parabolic reflectors
are rotated in unison to adjust their angle of tilt.
[0071] The upper frame 44' is relatively small in overall size, as
is the track 56. The frame 44' can be expanded to accommodate
essentially as many reflectors as necessary for any desired
facility by which reflected, line and point focused sunlight is
transformed into thermal and/or electrical energy.
[0072] The upper rotatable frame 44', illustrated in FIG. 3, is
shown as comprising end beams, or trusses, preferably of steel,
each generally designated 112, and an interior beam of steel,
generally designated 114. Other types of suitable trusses or beams
could be used.
[0073] Each end beam 112 is illustrated as comprising upper and
lower horizontal bars 116 and 118, which are integrally connected
as by welded to several vertical crossbars 120. The interior beam
114 comprises a plurality of horizontal members 122 and two
vertical members 124, such that the horizontal members 122 and the
vertical members 124 are welded together. A plurality of beams,
generally designated 130, transversely connect to the end beams 112
and the intermediate beam or beams 114 so that the upper rotatable
frame 44' is a rigid structure, providing ample support for the
reflectors, the energy converters and the reflector frames.
[0074] As best illustrated in FIG. 3, each parabolic trough-shaped
reflector 76 is supported by a reflector frame, generally
designated 140. While only eight reflector frames 140 are
illustrated in FIG. 3, as mentioned previously, the number of
reflectors and, accordingly, the number of reflector frames can be
expanded significantly beyond the small array illustrated in FIG.
3.
[0075] Each reflector frame 140 is essentially rigid and comprises
top and bottom longitudinally-directed bars 142 and 144, connected
by three trusses, each generally designated 146. Each truss 146
comprises a linear bar 148, a parabolic bar 150 and a plurality of
cross bars 152, transversely spanning between bars 148 and 150, all
ends of members 148, 150 and 152 being integrally connected as by
welding.
[0076] Each reflector frame 140 also comprises at least one central
longitudinally-directed support bar 154, welded to two end plates
156, by which the collective tilt of the reflectors is rotationally
adjusted in respect to the rotatable upper frame 44', as
hereinafter explained in greater detail. End axle journals 158 span
between each outside end plate 156 and one of the end frames 112
and function as explained hereinafter in greater detail. Adjacent
interior plates 156 are also connected one to another by a journal
mechanism, explained hereinafter in greater detail, by which joint
tilting rotation of adjacent reflectors and reflector frames is
accommodated.
[0077] The previously mentioned energy converters 54, one of which
is carried by each reflector frame 10 at the focal line of the
associated parabolic reflector, is supported by two cantilever arms
160 one disposed at each end of the converter 54. Each arm 160 is
connected by welding or the like to the central bar 1 54 and one
end truss 146 to rigidly hold the associated converter 54 at the
focal line of the associated reflector 76, the energy converter 54
bidirectional turning with the reflector as it is turned utilizing
the power toggle mechanism 52.
[0078] Each reflector 76, none of which is shown in FIG. 3, is
attached to each of the three associated parabolic members 150,
spanning the full length and width of the associated reflector
support frame 110. Rivets or other suitable fasteners may be used
to connect the reflector to the associated parabolic members 150.
Each reflector 76 is preferably comprised of polished sheet
aluminum or other suitable highly reflective material.
[0079] The energy converter 54 for each reflector 76 is supported
at the respective ends thereof by arm 160, which not only rigidly
connects to one of the ends of the associated converter 54 but also
at sites 151 and 153 (FIG. 5) to the associated reflector frame
140, as by welding.
[0080] Each converter 54 and the associated support arms 160 are
typically hollow to accommodate liquid flow within a pipe to,
through and from the converter 54 for the purpose of converting
line focused or point focused reflected sunlight to thermal energy
per se or in conjunction with the cooling of solar cells, which are
exposed to very high temperatures during conversion of reflected
point focused sunlight to electrical energy, as hereinafter
explained in greater detail.
[0081] From the foregoing, the significance of the illustration
comprising FIG. 4 should be readily apparent, namely that the
tracking optical sun detector 48 continuously senses the location
of the Sun in the sky relative to the azimuth and altitude of the
array of reflectors 76 and, to the extent, the reflectors 76 are
not collectively perpendicular to the sun, the differential is
detected by the bidirectional optical sensor 48 and signals are
issued to the motor and rotational drive 50 to place the axes of
the reflectors into a position of perpendicularity with the sun. In
addition, signals are issued by the detector 48 to the motor and
toggle tilting mechanism 52 by which the tilt of the parabolic
reflectors is placed in a perpendicular-relationship with the rays
of the sun, perpendicularity being intersection of the rays of the
sun with a line drawn between the upper and lower edges 170 and 172
(FIG. 4) of each reflector.
[0082] Thus, both from altitude and an azumith point of view, the
reflectors 76 are continuously adjusted so that reflector
perpendicularity is maintained with the rays of sunshine striking
each parabolic trough-shaped reflector. As a consequence, sunlight
reflected from each reflector 76 is line-focused upon the
associated energy converter 54, where the reflected, line-focused
solar energy is either converted to thermal energy or point-focused
and converted to electrical energy, as explained herein in greater
detail.
[0083] The relationship between the reflector trusses 150 and the
trough-shaped parabolic reflectors 76 is best illustrated in FIG.
5, in enlarged fragmentary perspective. In the configuration of
FIG. 5, two central longitudinal reinforcing bars 154 and 154' are
provided, in lieu of one, to enhance structural integrity.
[0084] In reference to FIG. 6, the optical detector 48 is
illustrated in greater detail. Detector 48 comprises an external
housing 170 which supports two shadow devices 172 and 174. Shadow
bar device 172 comprises a shadow bar 173, by which lack of
perpendicular alignment between the rays of the sun and the
altitude or tilt angle of the reflectors is detected by one or more
internal photocells. Shadow bar detector 174 comprises a shadow bar
175, by which lack of perpendicular azimuth or rotational alignment
is detected by one or more internal photocells. When the internal
photo cells detect a lack of either altitude or azimuth alignment
via shadows caused by rays of the sun striking the shadow bars 173
and/or 175, signals are issued to the motor and rotational drive 50
and/or motor and toggle tilting mechanism 52 to bring the
rotational position and the tilt position of the array of
reflectors again into perpendicularity with the rays of the sun,
after which the detector signals cease because no detectable shadow
exists and rational and/or tilt adjustments stop.
[0085] Reference is made now to FIGS. 7 and 8 with particularity in
respect to the types of energy converters which may be disposed at
converter site 54. FIG. 7 illustrates a converter by which solar
energy is transformed into thermal energy, while FIG. 8 illustrates
an embodiment by which solar energy may be reflected and point
focused for conversion into electrical energy. In respect to FIG.
7, a tube 176 is disposed at the focal line of reflector 76 so that
the rays of line focused, reflected sunlight 178 impinge directly
in concentrated form upon the thermally conductive material, such
as copper, from which the tube 176 is formed.
[0086] As the rays of reflected, line focused sunshine heat the
tube 176, liquid is displaced from source 178 through the tube 176
at a flow rate controlled by flow control 180. The liquid so
displaced is heated by the elevated temperature of the tube 176,
typically to a very high temperature along the focal line at 54,
with the effluent hot water or steam being delivered, for example,
to a heat exchanger 182, where the liquid or steam emerging from
tube 176 is used to heat another segregated liquid, which is
discharged from the heat exchanger as effluent from tube 184. The
liquid entering the heat exchange 182 as influent is, after the
heat exchanged process, discharged along tube 186, and is returned
to the source 178.
[0087] The liquid contained within source 178 and circulated as
indicated above may be, in selected instances, water and, in other
instances, a mixture of alcohol and water, as chosen by one skilled
in the art. Other suitable liquids may be used.
[0088] With specific reference to FIG. 8, the line focused
reflected solar energy 188 is caused to be point focused, for
example by a series of Fresnel lenses, as shown diagrammatically at
188 in FIG. 8. T he point focused rays 188 of sunlight are impinged
upon a series of solar cells 190, the characteristic of which
transforms the point of focus reflected sunlight 188 into direct
current electrical energy, which may be sold, stored or directly
utilized. In the alternative the DC electricity can be passed
through a DC/AC converter 192 to create alternating current
electricity, which may be stored, sold or directly utilized.
[0089] While not shown in FIG. 8, it is to be appreciated that the
solar cells 190 typically are mounted or otherwise made contiguous
to the external surface of a cooling tube to hold the temperature
of the solar cells 190 within a lower acceptable temperature range.
As a consequence, liquid contained within the cooling tube is
heated, which heated liquid may be utilized in any suitable fashion
including but not limited to the one described above in respect to
FIG. 7.
[0090] As mentioned earlier, in conjunction with FIG. 3, the
reflector frames 140 are collectively assembled so as to rotate in
unison around journals, such as end axle/journals assemblies 158,
the journals/assemblies axles, of any string or tandem of aligned
reflector frames 140 being disposed along a common axis. Each
journal/axle assembly 158 essentially comprise a central short axle
such that diametrically reduced ends of the axle fit within opposed
sleeves at opposite ends of the axle. Each axle is stabially
secured to the upper frame 44, 44; while the sleeves rotate around
the associated axle with the reflector frames.
[0091] Similarly, journals/axle assemblies 194 (FIG. 9) are
interposed between sequential aligned reflectors 76 and comprise
outer sleeves 196 at each end of the journal and a central short
axle comprising reduced diameter ends 198 rotatably disposed within
the sleeves 196. The axles comprising ends 198 are rigidly
connected to the upper frame 44, 44; while the sleeves 196 are
connected to and rotate with the reflector frames 140. As can be
seen from inspection of FIG. 9, the aligned axles of any aligned
group of reflector 76 creates an axis of rotation.
[0092] The previously mentioned toggle mechanism 52 may comprise a
motor-driven screw drive, generally designated 200, which comprises
an internally helically threaded cylinder 202 and a rod 204, the
internal end of which is threadedly engaged with the interior
threads of the cylinder 202, to accommodate extension and
refraction. The distal end 206 of the rod 204 is pivotally
connected, at 208, to a bracket comprising a pair of lugs 210. Lugs
210 are integrally connected, by welding, fasteners or the like to
a pair of toggle displacement bars 212 (only one of which is seen
in FIG. 9), which are reciprocated to an fro by the motor-driven
extension and retraction of rod 204. The distal ends 214 of the two
toggle bars 212 are respectively connected pivotally at 216 to,
adjacent anchor plates 218 welded or otherwise secured to
juxtaposed parallel trusses 146. The connection site 216 is
eccentrically located to facility rotation of the reflector frames
140 around the axles.
[0093] Thus, as detector 48 at shadow bar 173 photoelectrically
determines the need to adjust the tilt of the array of reflectors,
a signal is sent to the screw drive motor 230 (FIG. 12), which in
turn causes extension or retraction of the rod 104, which in turn
displaces the toggle bars 212 fore or aft to pivot the array of
reflectors in unison around the axles upon which the reflector
frames 140 are rotatably mounted. See FIG. 9. The toggle bars 212
consecutively pivotably and eccentrically connect at 216 to one of
each line of reflector frames 140, as best illustrated in FIG. 9,
so that all reflector frames 140 and all reflectors 76 rotate
together around parallel horizontal axes.
[0094] Keep in mind that the detector 48 (FIG. 6) is mounted to one
of the trusses 146 (FIG. 6) so that the shadow bars 173 and 175 are
in a plane essentially parallel to the plane containing bar 148 of
the truss 146 which supports the detector 48.
[0095] Specific reference is now made to FIG. 10 through 12, which
illustrate one way in which the toggle mechanism 52 may be
connected to adjacent reflector frames 146. The two toggle bars 212
are illustrated as being parallel and hollow structural members
having a rectangular cross section (FIG. 10). The toggle connection
plates 218 are illustrated in FIG. 10 as extending beyond the two
adjacent reflectors 76, as does the distal ends of each toggle bar
212. The pivotal connectors 216 are illustrated as being nut and
bolt assemblies pivotally passing through, in each case, the
associated toggle bar 212 and the connection plate 218, to
accommodate the previously mentioned changes in the tilt angle of
the array of reflectors 76 and reflector frame 140.
[0096] FIG. 11 is similar to FIG. 10, but illustrates the motorized
tilt adjusting mechanism 52 for the array of reflectors 76 from a
perspective essential opposite to perspective of FIG. 10.
[0097] The screw drive 200 is again illustrated in FIG. 12, which
further depicts motor 230, conventionally connected to transmission
or differential 232, so that when the reversible motor 230 is
actuated by a signal from the optical detector 48 (FIG. 6) to
unitarily alter the angular relationship of the array of reflectors
in respect to the vertical, the screw drive 200 is extended or
retracted, depending upon the displacement necessary to restore the
angle of tilt of the reflectors to perpendicularity with the rays
of the sun.
[0098] As mentioned earlier in conjunction with FIG. 1, the upper
frame 44 is rotatably mounted upon the curved track 56, which
track, as illustrated, is in the form of a circular I-beam. More
specifically, the upper rotatable frame 44 is made selectively
rotatable in respect to the stationary track 56 using a plurality
of load-transferring trucks 250, one of which is illustrated in
FIG. 13. Each truck 250, as illustrated, comprises a U-shaped
frame, generally designated 252, preferably formed of steel
comprising two pairs of lugs or ears 254 and a U-shaped bridge 256.
The lugs 254 and the bridge 256 are held in spaced relation in
respect to the I-beam track 56, as best illustrated in FIGS. 14 and
15. An upper frame displacement roller 258 is rotatably supported
by each lug 254 upon a shaft 260. Each shaft 260 is non-rotatably
carried by the associated lug 254 in the manner illustrated in FIG.
14. As best seen in FIGS. 13 and 14, each of the four rollers or
casters 258 frictionally engage and rotatably travel along the
upper surface of lower flange 60 of the I-beam track 56.
[0099] Each truck 252 is rigidly connected to the upper, rotatable
frame 44. This may be as illustrated in FIG. 13, i.e., by use of
two angle irons welded in spaced relation to the upper horizontal
surface of the associated bridge 256. See FIGS. 13 and 15,
specifically. The spacing between the vertically directed legs of
the angles 262, shown at 264 (FIG. 15) accommodates snug reception
of one horizontal member 45 of the upper frame 44. Nut and bolt
assemblies 266 (FIG. 13) are illustrated as being utilized to
fasten each angle piece 262 to the upper frame member 45.
[0100] Thus, a plurality of idler trucks 250 are used to provide
load transfer to the lower flange 60 of the I-beam track 56 and to
accommodate rotation of the upper frame 44 in respect to the lower
frame responsive to location correcting signals issued from the
optical detector 48.
[0101] To prevent the upper frame from jumping the track 56, each
truck 250 is equipped with vertically directed, web-engaging
opposed rollers 268. See FIG. 15. These rollers maintain
appropriate alignment between the upper frame and the trucks 250 in
respect to the lower frame and circular track 56. The rollers 268
contiguously engage the opposite surfaces of the web 52 of the
I-beam 56, each being rotatably mounted upon L-shaped axle 270,
which accommodates rotational travel by the rollers 268 along the
web 62 as the rollers 258 correspondingly travel along the upper
surface of the lower flange 60 of the I-beam 56.
[0102] Reference is now made to FIGS. 2 and 16 through 19, which
collectively illustrate the motor and rotational drive mechanism
50. The mechanism 50 comprises a reversible motor 280, which is
activated and deactivated by signals derived from the optical
sensor 48 by which the array of reflectors are maintained, from an
azimuth point of view, in a perpendicular orientation with respect
to the rays of the sun.
[0103] Reversible motor 280 rotates a differential or gear transfer
box 282, which in turn rotates an external drive shaft 284 (FIG. 1
8), which turns a drive sprocket 286, non-rotatably secured to the
shaft 284. The sprocket 286 turns to engage successive links 288 of
the previously mentioned drive chain (FIG. 2) 90. The chain drive
90 is statically secured, as by welding, at its distal and proximal
ends to the static I-beam track 56, providing enough length to
accommodate engagement with the sprocket 286. Rotational
displacement of the sprocket 286 causes the sprocket to walk, in
one direction or the other, along the links 288 of the chain 90 to
rotate the upper frame 44 upon the lower frame 42 to maintain
reflector perpendicularity with the sun from sunrise to sunset
during the longest day of the year in any location upon the face of
the earth. The chain 90, between welded ends, rests upon the top
surface of the lower flange 60, as shown in FIGS. 2, and 17-19.
Thus, the chain drive 90 is loose at all locations, except where it
is welded to the track 56 at its opposed ends. The length of the
chain drive 90 is selected so as to snugly pass around the sprocket
286 in taut relation.
[0104] Thus, rotation by motor 280 of the shaft 284 and the
sprocket 286, either clockwise or counterclockwise, will result in
the upper frame 44 turning in respect to the lower frame, in one
direction or the other, to maintain azimuth perpendicularity with
the sun, in the manner described earlier. Note that the motor 280
and the differential 282 are statically mounted upon a mounting
plate 292 of the upper frame 44. Mounting plate 292 is preferably
formed of steel and is bolted, welded or both to the upper frame
44. Signals from the optical detector 48 turn the reversible motor
280 on and off in one direction or the other consistent with
optical detection of non-azimuth perpendicularity between the array
of reflectors and the location of the sun in the sky.
[0105] As seen best in FIGS. 17 and 18, the chain 90 comprises a
U-shaped segment, generally designated 300, which passes tautly
around the sprocket 286. The sprocket contains teeth, sized and
shaped to engage hollow spaces within each link 288 of the chain
90. Accordingly, as the sprocket 286 is rotated by motor 280, the
differential 282 and the shaft 284, successive links 288 of the
chain drive 90 are engaged by the sprocket teeth causing the upper
frame 44 to rotate along the track 56 in the manner explained above
to preserve the mentioned perpendicularity. The motor 280 is
reversible and, therefore, shaft 284 may be turned in either
direction to move the upper frame 44 clockwise or counterclockwise
along the lower stationary track 56.
[0106] The present invention is not confined to any specific form
for the lower stationary frame and/or the upper displaceable frame.
Similarly, the present invention may be implemented by placing it
above the roof of an existing building supported by columns, on an
existing flat or sloped roof of an existing building, on or
immediately above an existing surface, such as a parking lot, for
example, on columns above an existing surface (to allow traffic
underneath) or in any other suitable location.
[0107] Reference is made to FIG. 20, which illustrates one way of
mounting an embodiment of the present invention comprising a lower
static frame 42' comprising a curved track 56', which is also
static, supported upon a plurality of columns 310 (only one of
which is illustrated), wherein the proximal end 312 of each column
extend into the ground and is encased in concrete 3 14, for
stability.
[0108] Each column 310 is secured as by welding at sites 3 14 to
the lower static truss 42'. Frame 42' is illustrated as comprising
a plurality of members 316, arranged conventionally to form
triangular supports. The structural members 316 may be of any
appropriate cross sectional shape, preferably formed of steel.
[0109] The track 56' is illustrated as being circularly disposed
with the flanges 58' and 60' being vertically not horizontally
directed and the web 62' being horizontally directed. The lower
edges of the flanges 58' and 60' contiguously engage and are
secured to the lower frame 42', as by welding. The load comprising
the reflectors, the reflector frames, the upper rotatable frame 44'
wind and/or snow comprise a substantial load transferred through a
plurality of trucks 252' and rollers 258' to the web 62' of the
track 56'.
[0110] Reference is now made to FIG. 21 which illustrates one way
in which large installations in accordance with the present
invention may be implemented. More specifically, two or more static
tracks 56, of the type previously described, are concentrically
provided so that a large array of reflectors and reflector frames
carried upon a displaceable upper frame may rotate in unison along
the plurality of tracks 56 as earlier described. Thus, the size of
any installation utilizing the present invention is flexible,
ranging from a very small installation comprising a few reflectors
to an extremely large installation comprising a large number of
reflectors.
[0111] Where a sequence of reflectors and reflector frames aligned
longitudinally one with another is utilized, in lieu of the motor
and toggle tilting mechanism 52, described above, a torque tube,
generally designated 330 in FIG. 22 may be used. The torque tube
330 may be of hollow tubular steel construction to which is
attached a plurality of tracking arms 332, joined, respectively, in
an eccentric disposition to each reflector frame 140 of a line of
such frames. Rotation of the torque tube 330 will in turn alter the
tilt angle of the associated reflectors 76 and reflector frames
140. This rotation is achieved by one or more drive arms 334
integrally connected as by welding to the tube 330. The distal end
336 is pivotally connected to the distal end of the previously
described rod 204 of the screw drive 200 so that extension and
retraction of the rod 204 rotates the torque tube 330 through the
drive arm 334 clockwise and counterclockwise, respectively, for the
purpose of adjusting the tilt of the related reflectors to preserve
perpendicularity with the rays of the sun, as mentioned earlier. A
plurality of torque tubes may be used as would be appropriate. More
than one screw drive 200 may be used in conjunction with any given
torque tube without departing from the spirit of the present
invention.
[0112] As mentioned previously, when the energy converter 54
transforms solar energy into thermal energy, a hollow tube 340
(FIG. 24) may be located at the focal line of the associated
reflector. Tube 340 may be of any thermally conductive material,
such as copper. A liquid is displaced through the hollow interior
342 as the line-focused sunlight 344 impinges upon and heats the
tube 340, causing the liquid contained in the tube 340 to be heated
from one temperature to a significantly higher temperature.
[0113] In the configuration of FIG. 24, a U-shaped housing 345 of
suitable material, such as sheet metal or, plastic surrounds part
of the tube 340 within the housing 345. The housing 345 comprises
opposed lower lips 346, which accommodate sheet reception and
retention of transparent lens 348, which may be glass or synthetic
resinous material. The tube 340 is illustrated as being imbedded,
in part, in a block of insulation 350, so that the heated liquid
within the hollow interior 342 of the tube 340 does not undesirably
or prematurely cool. The block of insulation 350 is illustrated in
FIG. 24 as surrounding approximately 260 degrees of the tube 340
when viewed in cross section, i.e., the top and most of the two
sides, leaving the bottom of the tube 340 open for impingement of
the reflected line-focused rays 344 of the sun through the lens 348
directly upon the exterior of the tube 340.
[0114] In lieu of the configuration illustrated in FIG. 24, the
embodiment of FIG. 25 may be utilized wherein the block of
insulation 350' extends only along 180 degrees of the exterior tube
340 when viewed in cross section.
[0115] As mentioned earlier, some or all of the focus lines of the
parabolic trough-shaped reflectors 76 may be equipped with
solar-to-electricity converters. More specifically, in reference to
FIG. 26, converter 54 may comprise a housing 360 having a tapered
hollow interior. The top of 362 may be equipped with a plurality of
aligned Fresnel lenses 364 Each Fresnel lens 264 comprises
concentric grooves upon which is impinged the reflected
line-focused sunshine 366. The grooves of each Fresnel lens
converts the reflected line-focused sunshine 366 to reflected
point-focused sunlight 368. Each segment of point-focused sunlight
is impinged upon one of the solar cells 190. Several commercially
available solar cells exist any of which may be used as solar cells
190. While the input to each solar cell 190 is solar energy, the
output is electrical energy, communicated from the
solar-to-electricity converter 54 upon electrical leads 370. This
electrical energy is direct current electricity. If alternating
current electricity is desired, DC/AC converter 192 may be utilized
from which conventional household electricity may be derived.
[0116] Continued reference is made to FIG. 26, which illustrates a
circular funnel-shaped secondary solar energy reflector 372
disposed above each solar cell 190, by which any stray solar energy
is reflected so that all sunlight passing through the associated
Fresnel lens 264 is caused to impinge upon the associated solar
cell 190.
[0117] As mentioned earlier, it is ordinarily appropriate to cool
the solar cells 190. This may be done by placing each solar cell
contiguously on the exterior of a cooling tube 374, through which
liquid coolant is displaced to not only cool the solar cells 190
but to convert the heat so transferred to useable thermal
energy.
[0118] In lieu of the circular funnel-shaped secondary reflectors
372, the reflectors 380 of FIGS. 27 and 28 may be used. Each
reflector 380 is rectangular in cross section with four downwardly
tapered flat walls intersecting at diagonally-disposed corners,
with a solar cell at the bottom of each reflector 380. In either
case, the internal surface of secondary reflectors 372 and/or 380
is selected to accommodate full reflection of any stray sunlight so
that all sunlight passing through any Fresnel lens 364 is caused to
impinge upon the associated solar cell 190.
[0119] Reference is now made to FIGS. 29 and 30, which illustrate
another reflector embodiment of the present invention with the
support frame on the convex or back side of the reflector, as
opposed to being on the front or concave side. More specifically,
all or any one of the parabolic trough-shaped reflectors 76 may be
supported on the back or reverse side thereof to provide a slightly
more unencumbered reflective surface. As shown in FIG. 29,
reflector 76 is supported by a reflector frame 400. Reflector frame
400 comprises the previously described upper and lower longitudinal
reinforcement of members 142 and 144. Midway between the members
142 and 144, on the back side of the reflector 76, are two
contiguous longitudinally extending rectangular supports 154"
comprising, at each end, blunt edges 155 essentially aligned with
the adjacent end edge of the associated reflector 76.
[0120] A plurality of parabolically shaped ribs, each generally
designated 402, span, at spaced intervals, between respectively
member 142 and one of the two central members 154" and between
member 144 and the other of the two central support members 154',
as illustrated in FIG. 29.
[0121] Each rib 402, as best illustrated in FIG. 30, comprises a
U-shaped brace having opposed outwardly directed flanges 404, which
are contiguous with and adhered by a simple bonding agent or the
like to the back surface of reflector 76 at interface sites 406.
The each rib 402 further comprises opposed parallel side walls 408,
which respectively merge with the associated one of the two flanges
404 essentially through a 90 degree angle. The spaced side walls
408 merge respectively at 90 degree corners with a back wall 410,
which is cut at opposite ends into integral end tabs 412 and 414.
Each end tab 412 is contiguous with and bonded to member 142 or
member 144, depending upon whether the rib is a top rib or a bottom
rib. See FIGS. 31 and 32.
[0122] In addition to the foregoing, the reflector frame 402 will
be rotatably connected to the previously described axle structure
and eccentrically to the previously described toggle mechanism to
accommodate rotation around a horizontal axis to accommodate
periodic changes in the tilt of the reflector 76 to preserve
perpendicularity with the rays of the sun, for the purposes set
forth above
[0123] The invention may be embodied in other specific forms
without departing from the spirit of the central characteristics
thereof. The present embodiments therefore to be considered in all
respects as illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than by the
foregoing description, and all changes which come within the
meaning and range of equivalency of the claims are therefore
intended to be embraced therein.
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