WO2011077266A2

WO2011077266A2 - Integrated electrical/thermal solar system with tracking axis along thermal pipe center-line and off-center lens for reduced wind resistance

Info

Publication number: WO2011077266A2
Application number: PCT/IB2010/051166
Authority: WO
Inventors: Sinan Doluca
Original assignee: Sinan Doluca
Priority date: 2009-12-23
Filing date: 2010-03-18
Publication date: 2011-06-30
Also published as: WO2011077266A3

Abstract

An integrated thermal/electric solar system has a water pipe that fits into a heat-transfer plate that supports the photovoltaic (PV) panel. A lens frame supports a Fresnel lens above the PV panel to concentrate sunlight. The lens frame is connected to a lens riser frame by spring hinges that allow rotation in the wind, allowing the lens frame to act as a weather vane and point downwind to reduce wind pressure and damage to the lens frame. Wheels around the water pipe roll in a track during tracking to follow sun movements. The lens riser frame is attached to the wheels. The PV panel, lens, lens frame, and lens riser frame all rotate as a unit around the centerline of the water pipe. Both electric and thermal energy from the sun are captured as the water from the water pipe can pre-heat a domestic hot-water supply.

Description

INTEGRATED ELECTRICAL/THERMAL SOLAR SYSTEM WITH TRACKING

AXIS ALONG THERMAL PIPE CENTER-LINE AND OFF-CENTER LENS FOR

REDUCED WIND RESISTANCE

FIELD OF THE INVENTION

[Para 1] This invention relates to solar energy systems, and more particularly to integrated thermal and photovoltaic solar panel systems.

BACKGROUND OF THE INVENTION

[Para 2] Renewable energy systems are desperately needed to provide clean energy that reduces pollution such as gas emissions that cause global warming. As the cost of oil rises due to geopolitical conflicts and dwindling reserves that are more expensive to extract, the relatively high cost of renewable energy systems is likely to reach break-even with traditional energy sources. Government subsidies also help reduce the cost of renewables.

[Para 3] Solar photovoltaic (PV) panels are widely deployed to create usable electric energy from sunlight. Solar thermal systems have been used to heat water for swimming pools and for household hot water heaters. Some solar systems create both heated water and electricity. These integrated solar electric/thermal systems can recover more of the sun's energy than separate PV and thermal systems.

[Para 4] Concentrated solar systems that use reflectors or lenses to focus a large area of sunlight on a small PV panel suffer from heating effects which can reduce efficiency of the PV cells. These concentrated solar systems may use cooling water to reduce the heating of the PV panels. Pipes attached to the PV panels carry water or other liquids to remove heat from the PV panels. The heat collected by this cooling water may be used to preheat water for other applications, such as hot water systems.

[Para 5] Concentrated solar systems often have tracking mechanisms to aim the solar concentrators and panels at the sun. However, when cooling water pipes are integrated with such systems, tracking movements may be hindered by placement of the cooling pipes or channels. Complex and clumsy tracking mechanisms and unwieldy panels may increase cost and maintenance problems.

[Para 6] High winds can also cause problems, especially for more complex integrated thermal/electric solar systems. Winds may place too much force on panels or hinges, resulting in breakage and high maintenance costs.

[Para 7] What is desired is an integrated thermal/electric solar system that creates both thermal and electric energy from the sun. An integrated thermal/electric solar system is desired that uses concentrators to increase energy collection density and tracking to follow the sun's movements. An integrated thermal/electric solar system with improved placement of cooling pipes is desired to enable unhindered tracking. Improved wind resistance is also desired.

BRIEF DESCRIPTION OF THE DRAWINGS

[Para 8] Figure 1 shows an integrated thermal/electric solar system.

[Para 9] Figure 2 shows a single integrated thermal/electric solar PV panel.

[Para 10] Figure 3 is a detail of the PV panel and heated-water pipe.

[Para 11] Figure 4 shows the lens frame and wheel/pipe assembly without the PV panel.

[Para 12] Figure 5A-B shows cross-sections of the pipe/heat-transfer plate/PV panel assembly.

[Para 13] Figures 6A-B are views of the PV assembly within a track.

[Para 14] Figures 7A-B highlight tracking movements of the PV/lens/pipe assembly within the track. [Para 15] Figures 8A-B show an alternate tracking mechanism.

[Para 16] Figures 9A-B highlight enhanced resistance to wind using the offset spring hinges on the lens frame.

[Para 17] Figures lOA-C show details of the keyed spring hinge.

[Para 18] Figure 11 is an alternate embodiment of the spring hinge.

[Para 19] Figure 12 is yet another alternate embodiment of the spring hinge.

DETAILED DESCRIPTION

[Para 20] The present invention relates to an improvement in integrated thermal/electric solar systems. The following description is presented to enable one of ordinary skill in the art to make and use the invention as provided in the context of a particular application and its requirements. Various modifications to the preferred embodiment will be apparent to those with skill in the art, and the general principles defined herein may be applied to other embodiments. Therefore, the present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.

[Para 21] Figure 1 shows an integrated thermal/electric solar system. An array of photovoltaic PV panels 11 are located to collect sunlight and convert it to electric energy, such as by using p-n junctions in silicon, gallium-arsenide, or other materials. Wires 22 connect together PV panels 11 and inverter 12, which converts a direct-current (DC) to an alternating current (AC) for use by households, businesses, and others. For example, inverter 12 may convert 200-400 volts DC from PV panels 11 to 110 volts AC for use by the electric grid.

[Para 22] PV panels 11 also have pipes attached. These pipes carry water that is heated by thermal energy produced by sunlight on the panels. External pipes 20 connect together pipes under PV panels 11 and carry the water in a loop to coils 15 inside water tank 14. Coils 15 heat the water inside water tank 14. The pre-heated water in water tank 14 can be piped to the inlet of a traditional water heater, reducing the heating load of the water heater. Cold water can be added to water tank 14 as water is drawn out, and water can be recirculated to water tank 14 by recirculating pump 26. This recirculated water can be cooled by radiator 26 when temperatures of the heated water are too high for efficient operation of PV panels 11. Radiator 26 may be equipped with a cooling fan (not shown) that is powered by backup power source 16.

[Para 23] Pump 24 moves the heated water through pipes 20 and PV panels 11 and into water tank 14. Pump 24 and recirculating pump 26 can be powered by a conventional source or may be powered by backup power source 16, which could also be a small solar- electric system producing about 15 volts DC.

[Para 24] The integrated thermal/electric solar system of Fig. 1 may produce about 2 kilo Watts (kW) of electric energy and 8 kW of thermal energy, for a total of 10 kW. Each PV panel 11 could be a 500 W panel with a PV surface area of 5 cm by 120 cm that receives concentrated light from a concentrator lens of 40 cm by 120 cm, or 8x concentration. Other embodiments with other specifications are also possible.

[Para 25] PV/Thermal Panel Assembly - Fig. 2

[Para 26] Figure 2 shows a single integrated thermal/electric solar PV panel. Each of PV panels 11 in Fig. 1 could include the assembly shown in Fig. 2, along with support, tracking, wiring, and other components that are not shown.

[Para 27] Sunlight strikes the top of lens 40, which can be a Fresnel lens that bends the sunlight to concentrate the sunlight onto the top surface of PV panel 10. PV panel 10 contains arrays of solar cells that generate electricity by capturing photons in p-n junctions in semiconductor material. A wide variety of technologies could be used to construct PV panel 10.

[Para 28] Lens 40 may be much wider than PV panel 10. For example, lens 40 could be 8 times wider than PV panel 10, producing a concentration factor of 8. Using lens 40 to concentrate sunlight reduces the size of PV panel 10 needed, reducing cost. For example, an 8x concentration can reduce the size and cost of PV panel 10 by 80%. More efficient and expensive panels may be used for PV panel 10 than with unconcentrated solar systems.

[Para 29] Lens 40 is held in lens frame 44, which grips lens 40 along its perimeter edges. Lens riser frame 46 provides a spacing between lens 40 and PV panel 10 that allows for optimal focusing of sunlight onto PV panel 10 by lens 40. Lens riser frame 46 is attached to lens frame 44 by spring hinges 42.

[Para 30] Spring hinges 42 allow lens frame 44 to rotate with respect to spring hinges 42 under high wind conditions. Once the wind force is removed, spring hinges 42 have springs that force lens frame 44 to be perpendicular to lens riser frame 46 as shown. Spring hinge 42 is offset from the center of lens riser frame 46 to provide an unequal wind force on lens 40 within lens frame 44. This unequal wind force allows lens 40 and lens frame 44 to pivot in the wind, reducing or preventing damage.

[Para 31] Lens riser frame 46 is fixedly attached to wheels 32, such as by bolts 48. Pipe 30 can be a copper water pipe that passes through the center of wheels 32 and is attached to wheels 32. PV panel 10 is clamped over pipe 30 as shown in detail in Fig. 5B.

[Para 32] The entire assembly shown in Fig. 2 rotates around centerline 34, which passes through the middle of pipe 30. Pipe 30, wheels 32, lens riser frame 46, and PV panel 10 are all fixedly attached to each other and rotated together as one unit. When no wind or other force occurs, lens 40 and lens frame 44 also rotated with the rotation of other components, since spring hinges 42 keep lens frame 44 perpendicular to lens riser frame 46. The entire assembly can be rotated along centerline 34 by moving wheels 32, allowing lens 40 and PV panel 10 to track apparent movements of the sun.

[Para 33] PV Panel Rotates Around Centerline of Water Pipe - Fig. 3

[Para 34] Figure 3 is a detail of the PV panel and heated-water pipe. PV panel 10 includes arrays of solar PV cells 36 on its top surface, which capture photons from sunlight and create electric current that can be carried away in electric wires (not shown). [Para 35] Pipe 30 can be a copper pipe for carrying water, such as a 1.25cm (1/2 inch) outside diameter pipe commonly used for plumbing systems. Pipe 30 is clipped into heat- transfer plate 38, which has a round groove on its bottom that snugly fits around pipe 30. See also Fig. 5B. Heat-transfer plate 38 can be formed from aluminum or another metal that transfers heat efficiently from PV panel 10 to pipe 30.

[Para 36] Figure 4 shows the lens frame and wheel/pipe assembly without the PV panel. Lens 40 is held in place within lens frame 44 such as by grooves that fit around the edges of lens 40. Clamps, screws, or other attachment methods may also be used. Lens 40 could be fastened to lens frame 44 much like a picture frame window. Lens frame 44 can be an aluminum frame with an L-shaped cross section with the addition of a small lip on the side of lens 40. Lens 40 could be pushed against this lip by a few spring loaded metal clips (as in a picture frame). This can also be accomplished by simply using sheet metal screws or fasters vertically from bottom to top (or horizontally). Lens frame 44 is attached to lens riser frame 46 by spring hinges 42, which allow lens frame 44 to pivot in the wind.

[Para 37] Lens riser frame 46 is attached to wheels 32 by four bolts 48 per wheel 32. When wheels 32 are rotated by a tracking mechanism, Lens40, lens riser frame 46, and lens frame 44 also pivot to track the sun with lens 40. Rotation is around centerline 34, which is the centerline of pipe 30.

[Para 38] Pipe 30 carries the heated water, which is heated by PV panel 10 (not shown). Pipe 30 is attached to wheels 32 such as by a locking screw, or by soldering, welding, or just by a snug fit. Thus when wheels 32 are rotated, pipe 30, lens riser frame 46, and lens frame 44 also pivot about centerline 34.

[Para 39] Figure 5A-B shows cross-sections of the pipe/heat-transfer plate/PV panel assembly. Fig. 5A is an exploded view of as plane perpendicular to pipe 30. Pipe 30 is a copper pipe that fits into a round groove on the underside of heat-transfer plate 38. Heat- transfer plate 38 can be an extruded aluminum plate that is somewhat flexible to allow pipe 30 to be forced into the groove, which has a split seam or slot in the bottom to allow pipe 30 to be forced into heat-transfer plate 38 during assembly. [Para 40] PV cells 106 are supported by printed-circuit board (PCB) 108 and may be formed on or in the substrate material of PCB 108. PCB 108 could be fiberglass with metal traces printed thereon to wire together the PV cells, or could be ceramic or semiconductor, polysilicon, or other materials. Protective glass cover 102 is held in place over PV cells 106 by bonding material 104, which could be a transparent glue, epoxy, or other adhesive, and may be a continuous later or may be placed around the perimeter of actual PV cells in PV cells 106 to not block sunlight.

[Para 41] Fig. 5B shows that protective glass cover 102, bonding material 104, PV cells 106, and PCB 108 fit into a bracketed area between sidewalls on the top of heat-transfer plate 38. Clamps or other mechanisms (not shown) may be bused to hold protective glass cover 102 within heat- transfer plate 38.

[Para 42] PV Assembly Rolls on Track - Figs. 6

[Para 43] Figures 6A-B are views of the PV assembly within a track. Wheel 32 rolls along track 50, which is a C-beam track with a lower channel that is strong enough to support the weight of wheel 32 and the PV/lens assembly of Fig. 2. In Fig. 6A, wheel 32 is attached to lens riser frame 46 by bolts 48, and pipe 30 passes through the center of wheel 32. PV panel 10 is attached to the top of pipe 32 by heat-transfer plate 38 (not shown for clarity). Hose clamp 110 attaches flexible hose 112 to the end of pipe 30. External pipes 20 of Fig. 1 can include flexible hose 112 between PV panels 11 rather than rigid pipes. Using flexible hose 112 allows pipe 30 to rotate within track 50.

[Para 44] Lens 40 is held within lens frame 44 above PV panel 10. Sunlight enters lens 40 from the top of Fig. 6A and is focused onto the top of PV panel 10. Heat is carried away by water flowing through pipe 30 and flexible hose 112.

[Para 45] Lens frame 44 is held to lens riser frame 46 by spring hinge 42, which can rotate when wind pressure is applied. A coil spring in spring hinge 42 forces lens frame 44 back into perpendicular alignment with lens riser frame 46 once pressure is removed. In Fig. 6B, spring hinge 42 is off-center to lens riser frame 46 and lens frame 44. This offset placement of spring hinge 42 better allows for wind to tilt lens frame 44 and alleviate wind pressure at the new angle to the wind.

[Para 46] In Fig. 6B, slot 52 in track 50 allows pipe 30 to pass through. Slot 52 can be large enough than pipe 30 does not touch the edges of slot 52. Pipe 52 does not support the PV panel assembled within slot 52. Instead, the larger wheels 32 support the weight of the PV assembly onto the bottom of track 50.

[Para 47] Tracking - Figs. 7-8

[Para 48] Figures 7A-B highlight tracking movements of the PV/lens/pipe assembly within the track. In Fig. 7A, two PV/lens/pipe assemblies are shown in track 50. Each PV assembly has lens 40 that concentrates sunlight 100 onto PV panel 10 that rests above pipe 30 that carries the heated water. Lens riser frame 46 holds lens 40 in lens frame 44 above PV panel 10 and pipe 30.

[Para 49] Wheels 32 have pipes 30 passing through their centers and through slots 52 in track 50. Wheels 32 roll along the bottom of track 50 in response to movements of rods 54, which are attached to wheels 32 by bolts 58.

[Para 50] A light sensor includes two small PV panels or other light sensors 114, 116 that are attached to two bevel edges on the top of sensor riser 146. When sensor riser 146 is exactly aligned to the direction of sunlight 100, the amount of light hitting light sensor 114 equals that hitting light sensor 116. Light sensor and servo controller 134 adjusts the tilt of sensor riser 146 until this condition is reached. When light sensor 114 produces more electric current than light sensor 116, light sensor and servo controller 134 activates a servo or motor (not shown) to rotate sensor riser 146 to the left. When light sensor 116 produces more electric current than light sensor 114, light sensor and servo controller 134 activates the servo or motor to rotate sensor riser 146 to the right. Thus sensor riser 146 tracks movement of sunlight 100 to optimize the amount of sunlight 100 hitting PV panels 10. [Para 51] Servo wheel 132 is attached to sensor riser 146 by bolts. Servo wheel 132 is rotated by light sensor and servo controller 134 rolling servo wheel 132 to the right or left in track 50. Gears 135 on servo wheel 132 engage teeth on rack 133 on track 50 to provide more precise movement. A rod (not shown) attached to a servo (not shown) controlled by light sensor and servo controller 134 could be attached to servo wheel 132 to provide movement.

[Para 52] Servo wheel 132 is attached to rods 54 by bolts 158. As servo wheel 132 rotates in response to light sensor and servo controller 134, rods 54 move, one to the right and the other to the left. This movement of rods 54 is transmitted to wheels 32 by bolts 58.

[Para 53] Fig. 7B shows further tracking movements. Sunlight 100 has shifted due to passage of time in the day. Light sensor and servo controller 134 has adjusted the pivot of sensor riser 146 so that equal electric current is produced by light sensors 114, 116.

(Gears 135 on servo wheel 132 and teeth on rack 133 are not shown in this diagram).

[Para 54] The rotation of servo wheel 132 causes the top rod 54 to move to the left more than bottom rod 54 move to the left as the arrows show. The movement of rods 54 is transmitted through pins or bolts 58 to wheels 32. The rotation of each wheel 32 causes lens riser frame 46 and lens frame 44 to tilt with PV panel 10. Sunlight 100 is now concentrated through lens 40 onto PV panel 10 despite the new angle of sunlight 100.

[Para 55] Figures 8A-B show an alternate tracking mechanism. In this embodiment, pipe 30 supports the PV/lens/pipe assembly. Pipe 30 fits in ball bearings 138, which allow pipe 30 to freely rotate. Ball bearings 138 are mounted to the side of track 150. Track 150 does not contact wheels 32. Instead track 150 supports pipe 30 through ball bearings 138. Wheels 32 do not have to be round in shape in this embodiment but could be rectangular or some other shape. Wheels 32 could be deleted as shown in Fig. 8B. Then lens riser frames 46 directly fit around pipe 30, or attach to ball bearings 138. In a sense, ball bearings 138 then act as wheels 32. [Para 56] Rod 54 attaches to lens riser frames 46 by bolts 58. A light sensor (not shown) controls servo controller 135, which activates linear servo 144. Linear servo 144 moves rod 54 as needed.

[Para 57] In Fig. 8B, Sunlight 100 has shifted due to passage of time in the day. The light sensor has commanded servo controller 135 to activate linear servo 144. Linear servo 144 has pulled rod 54 to the left as shown by the arrow.

[Para 58] The pull of rod 54 causes lens riser frames 46 to be pulled to the left through bolts 58, which have a sheathing, a pin secured with a cotter pin, or other mechanism to allow pivoting. As lens riser frame 46 is pulled to the left, the PV/lens/pipe assembly pivots around pipe 30. Ball bearings 138 allow pipe 30 to freely rotate and still be supported by track 150.

[Para 59] The pull form bolt 48 and lens riser frame 46 causes rotation of pipe 30, which in turn causes PV panel 10 to tilt with lens riser frame 46 and lens frame 44. Sunlight 100 is now concentrated through lens 40 onto PV panel 10 despite the new angle of sunlight 100.

[Para 60] Offset Spring Hinges Provide Wind Tolerance - Figs. 9

[Para 61] Figures 9A-B highlight enhanced resistance to wind using the offset spring hinges on the lens frame. Fig. 9A shows the default position when there is little or no wind. A coil spring applies pressure to a keyed hinge in spring hinges 42 that forces lens frame 44 to be in a perpendicular position to lens riser frame 46 as shown in Fig. 9A.

[Para 62] When wind blows against lens 40 and lens frame 44, a force is imparted by the wind onto lens frame 44. This force is generally proportional to the surface area of the lens that the wind strikes, for any angle of the wind. This assumes that the wind is striking all parts of the lens at about the same angle, which is likely as an approximation.

[Para 63] If spring hinges 42 were centered on lens frame 44, the surface areas of the left and right halves of lens frame 44 would be the same, and the wind would exert the same force on both left and right halves of lens frame 44. Since the force on both halves would be the same, lens frame 44 would not pivot in the wind.

[Para 64] Offset Lens Frame Pivots in Wind

[Para 65] However, when spring hinges 42 are located off the center of lens frame 44, the surface areas of the left and right halves of lens frame 44 now differ. For example, Fig. 9A shows that spring hinges 42 are offset to the left of center. Thus there is less surface area on the left half than on the right half of lens frame 44. More force is exerted by the wind on the right half of lens frame 44.

[Para 66] In Fig. 9B, the wind is blowing from the lower left to the upper right. The wind impacts the lower surface of lens frame 44 since the wind is coming from below, such as by bouncing off the building's roof. Since the right half of lens frame 44 has a larger surface area than the left half of lens frame 44, more force is exerted on the right half of lens frame 44, and the right half of lens frame 44 is pushed upward by the wind. If lens frame 44 is pushed too far, the wind hits the top surface of lens frame 44, and pushed the larger right half of lens frame 44 back down. Eventually, lens frame 44 reaches an equilibrium position where the wind force on the top and bottom surface of the right half of lens frame 44 are equal. This equilibrium position is when lens frame 44 exactly lines up with the wind direction, as shown in Fig. 9B.

[Para 67] Offset Lens Frame Acts As a Weather Vane

[Para 68] The operation of the offset lens frame 44 is much like that of a weather vane or wind vane. The tail of the weather vane has a large tail with a larger surface area than the head. The wind forces the large tail to be parallel to the wind direction to even the forces on both sides of the large tail. Thus the large tail points to the downwind direction.

[Para 69] When lens frame 44 is lined up in the equilibrium position, parallel to the wind flow, the forces on the top and bottom surfaces of lens frame 44 are reduced toward zero. The wind blows across the surfaces rather than impacting upon the surfaces. The force applied by the wind onto lens frame 44 is thus reduced. Damage from the wind is reduced or avoided. As the wind shifts direction, lens frame 44 pivots like a wind vane to reduce the wind pressure. Thus the offset pivoting lens frame 44 is less prone to wind damage than fixed- angle designs and pivoting but centered designs.

[Para 70] Spring Hinge - Figs. 10

[Para 71] Figures lOA-C show details of the keyed spring hinge. In this embodiment of spring hinges 42, coil spring 70 of Fig. 10A exerts a force between spring ends 72. 74. One spring end 72 is fixed to lens frame 44, while the other spring end 74 is fixed to lens riser frame 46.

[Para 72] When a rotational force is applied between spring ends 72, 74, such as by the wind impacting the surface area of lens 40 within lens frame 44, coil spring 70 compresses or expands, depending on the direction of the rotational force. Coil spring 70 resists this compression or expansion with an opposite force, a spring force, produced by the metal in coil spring 70. This spring force later causes spring ends 72, 74 to return to their resting position once the rotational force from the wind is removed.

[Para 73] Fig. 10B shows a keyed hinge in the spring hinge. Upper cylinder 90 is attached to lens frame 44 by upper screws 80, 82, which have their screw heads 180 facing downward at the interface between upper cylinder 90 and lower cylinder 92.

[Para 74] Lower cylinder 92 is attached to lens riser frame 46 by lower screws 84, 86, which have their screw heads 184 facing upward at the interface between upper cylinder 90 and lower cylinder 92.

[Para 75] Upper cylinder 90 and lower cylinder 92 are able to freely rotate around axis rod 94, 96, which can be a rod that fits between holes in both lens frame 44 and lens riser frame 46.

[Para 76] Upper cylinder 90 and lower cylinder 92 are also able to freely rotate relative to each other. An angled extrusion key section of upper cylinder 90 extends downward into similarly- shaped hollowed section of lower cylinder 92 near axis rod 94, 96. A "keyed" hinge has two halves that are fitted in one position, and a certain amount of force is needed to overcome the interlocking and to separate the two halves thus causing a rotation. A peg or other key (not shown) can be inserted in upper cylinder 90 and into a slot in lower cylinder 92 to limit the total rotational movement allowed, or no peg can be used and the spring limits rotation.

[Para 77] In Fig. IOC, coil spring 70 is placed around upper cylinder 90 and lower cylinder 92. Upper cylinder 90 is attached to lens frame 44 by upper screws 80, 82, while spring end 72 is also attached to lens frame 44, such a by fitting into a hole. Axle rod 94 also fits into a hole in lens frame 44.

[Para 78] Lower cylinder 92 is attached to lens riser frame 46 by lower screws 84, 86. Spring end 74 of coil spring 70 is also attached to lens riser frame 46, such as by fitting into a hole. Axle rod 96 also fits into a hole in lens riser frame 46. Spring hinge 42 is the connection between lens frame 44 and lens riser frame 46.

[Para 79] As lens frame 44 rotates relative to lens riser frame 46 around axle rod 94, 96, the relative positions of spring ends 72, 74 change, exerting a force on coil spring 70. Upper cylinder 90 rotates relative to lower cylinder 92. When the force is removed, coil spring 70 forces spring ends 72, 74 back to their original position, forcing lens frame 44 and lens riser frame 46 back to their perpendicular position shown in Fig. 9A.

[Para 80] Figure 11 is an alternate embodiment of the spring hinge. Coil spring 70' has fewer turns and exerts less force than coil spring 70 of Figs. 10. However, central coil spring 76 is placed around axle rod 94, 96 in a cavity within upper cylinder 90 and lower cylinder 92. Central coil spring 76 supplies an additional force between its ends, which are fixed to upper cylinder 90 and to lower cylinder 92. Spring hinge 42' May be less expensive than spring hinges 42 or may have other advantages. For example, the embodiment of Fig. 10 combines the rotational and vertical force in one spring (as shown in Fig. IOC) whereas the embodiment of Fig. 11 has two separate springs. [Para 81] Figure 12 is yet another alternate embodiment of the spring hinge. The embodiment of Fig. 12 is very simple yet effective. Lens frame 44 and lens riser frame 46 pivot about spring hinge 42". Shaft 91 is a generally cylindrical body, but with a flat edge rather than a curved edge at the top of Fig. 12. Shaft 91 is attached to lens frame 44 by upper screws 80, while spring end 72 of coil spring 70" is also attached to lens frame 44, such a by fitting into a hole or slot, or by welding.

[Para 82] Spring end 74 of coil spring 70" is attached to lens riser frame 46, such a by fitting into a hole or slot, or by welding. Shaft 91 fits into a hole in lens riser frame 46 and can rotate within that hole with respect to lens riser frame 46, but is fixed to lens frame 44.

[Para 83] Screws 78 attach the ends of wire 77 to lens riser frame 46. Wire 77 fits across the flat edge of shaft 91. As shaft 91 rotates, wire 77 exerts a force against the flat edge of shaft 91, tending to force shaft 91 to return to its resting position.

[Para 84] As lens frame 44 rotates relative to lens riser frame 46 around shaft 91, the relative positions of spring ends 72, 74 change, exerting a force on coil spring 70". When the force is removed, coil spring 70" forces spring ends 72, 74 back to their original position, forcing lens frame 44 and lens riser frame 46 back to their perpendicular position shown in Fig. 9A. Also, wire 77 forces the flat edge of shaft 91 back to its resting position.

ALTERNATE EMBODIMENTS

[Para 85] Several other embodiments are contemplated by the inventor. For example, many variations of spring hinges 42 are possible, such as combinations of features shown in Figs. 10-12. A compression spring rather than a coil spring could be used. The amount of wind force required to pivot the lens frame can be adjusted to meet expected worst- case high- wind velocities for the installation, or for other factors. [Para 86] Some parts have been described as being made from various material such as copper or aluminum, but could be made with other materials such as plastics, other kinds of metals or alloys, ceramics, composites, etc. The PV panels could be made by a wide variety of technologies and use a wide variety of materials, and could include one p-n junction layer or multiple p-n junction layers. While a concentration factor of 8 has been described, other concentration factors could be used. Various kinds of Fresnel lenses and lens assemblies could be used. Many variations and combinations of tracking

mechanisms may be substituted that still rotate the PV lens assemblies around the water- pipe center line axis.

[Para 87] Other backup power sources, pumps, radiators, tanks, and panel arrangements could be substituted, and components can have various specifications such as voltages and sizes. While heated water has been described, other liquids in a closed loop could be used, or even liquid-gas condensation systems. While copper and aluminum parts have been described, other materials could be used, especially high heat-transfer-coefficient materials.

[Para 88] Radiator 28 (Fig. 1) may be located in the primary heated water loop of pipes 20 rather in the secondary water loop. Multiple radiators could also be used in one or both loops for especially hot locations. Water tank 14 could be combined with the primary water heater, or the water heater could be eliminated or replaced with a flash water heater or other secondary heater. More complex heating loops could be used in industrial or institutional locations.

[Para 89] A heat transfer paste could be brushed over the outside of pipe 10 before its insertion into heat-transfer plate 38 to further enhance heat transfer between heat-transfer plate 38 and pipe 10, or pipe 10 could be formed as part of heat-transfer plate 38.

[Para 90] While screws and bolts have been described, other kinds of fasteners could be substituted in some cases, such as rivets, crimps, pegs, keyed parts, and Cotter pins. Many kinds of springs and deformable materials may be used for coil spring 70 and other parts. The shape of lens riser frame 46 could be varied, such as by having a wider top than its bottom, or by having cutouts or holes to allow the wind to pass through. When ball bearings around pipe 30 are used, wheels 32 do not have to roll, and thus can take on arbitrary non-round shapes, or may be formed as part of lens riser frame 46 or some other part.

[Para 91] Rather than have a sensor that senses the direction of sunlight, the sensor could be replaced by a computer or other apparatus that tracks a pre-calculated course of the sun's movements for various days of the year, or that approximates the sun's movements. The computer then moves the servo by a calculated amount. A combination of pre-calculated movements and a sensor could also be employed, such as to pre-position the assembly on cloudy days.

[Para 92] While the water pipes have been described as being connected in a serial, daisy-chain fashion, manifolds could be added to allow for parallel paths in the water loop. Likewise, the electrical connections could have parallel paths rather than have all PV panels connected together in one electrical loop.

[Para 93] Each solar cell could add FET bypass circuitry to detect shading and avoid power loss due to localized shading of a cell. This could be a problem with a single axis tracker due to edge shading near the standoffs. Another solution is to make the lens somewhat longer in the axis direction on both ends of the panel. Another solution is to bypass the edge PV cells with circuitry during shading.

[Para 94] The background of the invention section may contain background information about the problem or environment of the invention rather than describe prior art by others. Thus inclusion of material in the background section is not an admission of prior art by the Applicant.

[Para 95] Any methods or processes described herein are machine-implemented or computer-implemented and are intended to be performed by machine, computer, or other device and are not intended to be performed solely by humans without such machine assistance. Tangible results generated may include reports or other machine-generated displays on display devices such as computer monitors, projection devices, audio- generating devices, and related media devices, and may include hardcopy printouts that are also machine-generated. Computer control of other machines is another tangible result.

[Para 96] Any advantages and benefits described may not apply to all embodiments of the invention. When the word "means" is recited in a claim element, Applicant intends for the claim element to fall under 35 USC Sect. 112, paragraph 6. Often a label of one or more words precedes the word "means". The word or words preceding the word "means" is a label intended to ease referencing of claim elements and is not intended to convey a structural limitation. Such means-plus-function claims are intended to cover not only the structures described herein for performing the function and their structural equivalents, but also equivalent structures. For example, although a nail and a screw have different structures, they are equivalent structures since they both perform the function of fastening. Claims that do not use the word "means" are not intended to fall under 35 USC Sect. 112, paragraph 6. Signals are typically electronic signals, but may be optical signals such as can be carried over a fiber optic line.

[Para 97] The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.

Claims

I Claim:

1. An integrated thermal/electric solar panel assembly comprising:

a pipe for carrying a thermal-transfer fluid that is heated by solar energy;

a photovoltaic (PV) panel having cells formed on a first surface for generating electric current from solar energy;

wherein the PV panel is mounted to the pipe so that heat from the PV panel is transferred to the pipe;

a pair of wheels mounted around the pipe at opposite ends of the PV panel, wherein each wheel has a center opening that the pipe passes though;

a pair of lens riser frames, each lens riser frame attached to a wheel;

a lens frame pivotally attached to the pair of lens riser frames; and

a lens supported by the lens frame, wherein the lens is situated to concentrate sunlight upon the first surface of the PV panel;

wherein the integrated thermal/electric solar assembly pivots around a centerline of the pipe, the centerline of the pipe passing through a center of the pipe and being a rotational axis of the integrated thermal/electric solar assembly;

wherein the integrated thermal/electric solar assembly pivots around the centerline to track apparent movements of a sun.

2. The integrated thermal/electric solar panel assembly of claim 1 further

comprising:

a pair of tracks, each track receiving a wheel of the pair of wheels, wherein each wheel rolls along the track to pivot the PV panel and the lens in the lens frame;

a tracker for tracking apparent movements of the sun, the tracker rolling the pair of wheels in the pair of tracks to pivot the PV panel and the lens to follow the apparent movements of the sun, whereby the tracker rolls the pair of wheels to pivot the PV panel and lens around the centerline of the pipe that carries the thermal-transfer fluid heated by solar energy heating the PV panel.

3. The integrated thermal/electric solar panel assembly of claim 2 further

comprising:

a tracking rod, attached to a wheel in the pair of wheels, for rolling the wheel in the track; a rod mover, responsive to the tracker, for moving the tracking rod in response to the apparent movements of the sun.

4. The integrated thermal/electric solar panel assembly of claim 3 wherein the rod mover is a linear servo or a servo wheel that is rotated by a gear mechanism.

5. The integrated thermal/electric solar panel assembly of claim 2 further

comprising:

a slot in each track, the slot sized to permit the pipe to pass through;

a flexible hose, attached to an end of the pipe past the slot in the track, wherein the

flexible hose connects the pipe to pipes for other instances of the integrated thermal/electric solar assembly at a solar installation.

6. The integrated thermal/electric solar panel assembly of claim 2 wherein the lens is a Fresnel lens.

7. The integrated thermal/electric solar panel assembly of claim 2 further

comprising:

a heat-transfer plate coupled between the PV panel and the pipe;

wherein the PV panel further comprises a second surface opposite the first surface,

wherein the first surface is pointed towards the sun to collect sunlight;

wherein the pipe is mounted to the second surface of the PV panel by the heat-transfer plate.

8. The integrated thermal/electric solar panel assembly of claim 7 wherein the PV panel is mounted over the pipe, wherein the PV panel blocks sunlight to the pipe, the pipe being mounted behind the PV panel.

9. The integrated thermal/electric solar panel assembly of claim 7 further

comprising:

a seam slot in the heat-transfer plate, the seam slot for receiving the pipe, wherein the pipe is snapped into the seam slot during manufacturing.

10. The integrated thermal/electric solar panel assembly of claim 1 further

comprising:

a spring hinge coupled between the lens frame and the lens riser frame, the spring hinge pivotally attaching the lens frame to the lens riser frame;

a spring within the spring hinge, the spring for forcing the lens frame into a substantially perpendicular position relative to the lens riser frame when a wind force is absent, and for allowing the lens frame to pivot away from the substantially perpendicular position relative to the lens riser frame when the wind force is present, whereby the lens frame pivots about the spring hinge when the wind force is present.

11. The integrated thermal/electric solar panel assembly of claim 10 wherein the spring hinge is mounted to the lens frame in an offset position, wherein a pair of the spring hinge attached to the pair of the lens riser frames divides the lens frame into two halves with differing surface areas that receive differing wind forces, whereby the spring hinge is offset to create a difference in the wind force on two halves of the lens frame.

12. The integrated thermal/electric solar panel assembly of claim 1 further

comprising: a ball bearing assembly, wherein the ball bearing assembly is attached to the pipe and is attached to a track frame to permit the integrated thermal/electric solar assembly to pivot around the centerline of the pipe using the ball bearing assembly to support the pipe,

wherein the ball bearing assembly supports the integrated thermal/electric solar assembly at the pipe;

wherein each wheel in the pair of wheels has an arbitrary shape and connects the lens riser frame to the pipe.

13. An integrated thermal/electric solar system comprising:

a plurality of assemblies, each assembly in the plurality of assemblies comprising:

a photovoltaic (PV) panel for generating electric energy from sunlight;

a heat-transfer plate supporting the PV panel;

a pipe mounted to the heat-transfer plate, the pipe for carrying water heated by waste heat from the PV panel;

a lens mounted above the PV panel, the lens for concentrating sunlight onto the

PV panel;

a lens frame for supporting the lens;

a first lens riser frame pivotally connected to the lens frame and fixed to the pipe near a first end of the pipe;

a second lens riser frame pivotally connected to the lens frame and fixed to the pipe near a second end of the pipe;

a stationary frame that pivotally supports each assembly in the plurality of assemblies; a rotating support mechanism that supports each assembly in the plurality of assemblies in the stationary frame and permits the assembly to rotate along a centerline of the pipe;

a tracker that pivots each assembly in the plurality of assemblies to point the lens and PV panel toward a sun to track sunlight;

a water loop that forces water through the pipe in the assembly and transfers water heated by the PV panel to an external tank for heating an external water source, whereby each assembly pivots along the centerline of the pipe to track sunlight to generate electric energy and heated water.

14. The integrated thermal/electric solar system of claim 13 wherein each assembly in the plurality of assemblies further comprises:

a first spring hinge coupled between the lens frame and the first lens riser frame, the first spring hinge pivotally attaching the lens frame to the first lens riser frame;

a second spring hinge coupled between the lens frame and the second lens riser frame, the second spring hinge pivotally attaching the lens frame to the second lens riser frame;

a first spring within the first spring hinge, the first spring for forcing the lens frame into a substantially perpendicular position relative to the first lens riser frame when a wind force is absent, and for allowing the lens frame to pivot away from the substantially perpendicular position relative to the first lens riser frame when the wind force is present;

a second spring within the second spring hinge, the second spring for forcing the lens frame into a substantially perpendicular position relative to the second lens riser frame when the wind force is absent, and for allowing the lens frame to pivot away from the substantially perpendicular position relative to the second lens riser frame when the wind force is present;

whereby the lens frame pivots about spring hinges when the wind force is present.

15. The integrated thermal/electric solar system of claim 14 wherein the first spring hinge is mounted to the lens frame in an offset position that is not centered on the first lens riser frame;

wherein the second spring hinge is mounted to the lens frame in an offset position that is not centered on the second lens riser frame;

wherein the first spring hinge and the second spring hinge divide the lens frame into two halves with differing surface areas that receive differing wind forces, whereby the first spring hinge and the second spring hinge are offset to create a difference in the wind force on two halves of the lens frame.

16. The integrated thermal/electric solar system of claim 15 wherein the rotating

support mechanism comprises:

a first ball bearing surrounding and supporting the pipe near the first end of the pipe and mounted to the stationary frame;

a second ball bearing surrounding and supporting the pipe near the second end of the pipe and mounted to the stationary frame,

whereby the pipe pivots within ball bearings.

17. The integrated thermal/electric solar system of claim 15 wherein the rotating

support mechanism comprises:

a first wheel having a first hole through its center, the pipe passing through the first hole, the first wheel connected to the first lens riser frame;

a second wheel having a second hole through its center, the pipe passing through the second hole, the second wheel connected to the second lens riser frame;

wherein the stationary frame comprises:

a first track that is sized to accept the first wheel, wherein the first wheel rolls within the first track and is supported by the first track;

a second track that is sized to accept the second wheel, wherein the second wheel rolls within the second track and is supported by the second track;

wherein the assembly pivots to track the sun when the first and second wheel are rolled within the first and second tracks.

18. The integrated thermal/electric solar system of claim 15 wherein the water loop comprises:

coils in an external water tank, the coils heating water in the external water tank for use as a heated water supply; a pump for forcing water to flow from the coils to the pipe in the assembly and back to the coils in the external water tank;

a plurality of the pipe in the plurality of assemblies; and

flexible hoses that connect ends of the pipe in an assembly to pipes in other assemblies in the plurality of assemblies.

19. A wind-tolerant integrated thermal/electric solar assembly comprising:

a photovoltaic PV panel for generating electricity from sunlight;

a lens for concentrating sunlight onto a top surface of the PV panel;

a lens frame for holding the lens;

a pipe for carrying water to be heated by the PV panel;

a heat-transfer plate that holds the PV panel and the pipe and transfers heat from the PV panel to the pipe;

a first wheel sharing a center with a centerline of the pipe;

a first lens riser frame fixed to the first wheel;

a first spring hinge that connects the first lens riser frame to the lens frame, the first spring hinge allowing the lens frame to pivot with respect to the first lens riser frame in response to a wind force on the lens frame;

a second wheel sharing a center with the centerline of the pipe;

a second lens riser frame fixed to the second wheel;

a second spring hinge that connects the second lens riser frame to the lens frame, the second spring hinge allowing the lens frame to pivot with respect to the second lens riser frame in response to the wind force on the lens frame;

wherein the first spring hinge is offset from a center of the lens frame;

wherein the second spring hinge is offset from the center of the lens frame;

a first track for supporting the first wheel, wherein the first wheel rolls along the first track to pivot the PV panel and the lens toward the sun; and

a second track for supporting the second wheel, wherein the second wheel rolls along the second track to pivot the PV panel and the lens toward the sun.

20. The wind-tolerant integrated thermal/electric solar assembly of claim 19 wherein the first spring hinge comprises:

an upper cylinder fastened to the lens frame;

a lower cylinder fastened to the first lens riser frame;

an axis rod passing through a center of the upper cylinder and through a center of the lower cylinder;

a coil spring that surrounds the upper cylinder and surrounds the lower cylinder, the coil spring having a first end attached to the lens frame and a second end attached to the first lens riser frame;

wherein the upper cylinder rotates relative to the lower cylinder in response to the wind force.