Solar energy collection assembly

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

SOLAR ENERGY COLLECTION ASSEMBLY

[0001] The present invention relates to solar energy collection assemblies and systems and more particularly to those assemblies and systems that can be easily mounted on top of building structures and forming a roof like structure, though the solar energy collection assembly could stand alone.BACKGROUND

[0002] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

[0003] The fixed mirror distributed focus (FMDF) solar collector, also known as a “solar bowl”, as described in Stine and Harrigan “Power from the Sun” http: / / www.powerfromthesun.net / book.html, is a solar thermal power technology which has been studied for several years as a potential means of producing electricity, though heat or any other sunlight collection method could be adopted. The solar bowl technology broadly uses a fixed, non-tracking concave spherical mirrored surface which concentrates sunlight to a “focal line” as per Stine and Harrigan, with this focal line positioned through the centre of the spherical mirror and pointing towards the sun. Figure 1 reproduced from Stine and Harrigan shows this graphically, with the centre of the spherical mirror marked as “C”. A two-axis tracking sunlight receiver moves to align with the movement of the focal line throughout the day.

[0004] From 1974 to 1982 Texas Tech University demonstrated such a 65 ft diameter FMDF solar bowl collector located at Crosbyton Texas. This bowl demonstrated low collector efficiency and since then there have been sporadic attempts at related concepts. The low collector efficiency is due to the non-tracking of the mirrored surfaces such that the aperture of the bowl does not align normal with the sun’s rays for most of the day. A key advantage of the solar bowl however is that the large-scale reflecting surfaces are spherical (actually sub-portions of a sphere) and stationary, with the only moving part being the “receiver” moving with the focal line. This simplifies mounting of the whole assembly, and also simplifies manufacture and installation since all reflector sub-portions being of the same radius are stackable hence more readily transportable, and possibly somewhat easier to incorporate into a building structure (e.g. as a roof) since this assembly looks like an inverted dome.

[0005] As described above a spherical reflector concentrates light energy along a focal line that is always through the centre of the sphere and directed at the light source irrespective of the location of the light source above the bowl. Figure 1 demonstrates this effect (Stine and Harrigan, 2001. Power From The Sun at: https: / / www.powerfromthesun.net / book.html), and illustrates the “cosine” error (described below) of not aligning the collector aperture normal to the sun’s rays is manifest in the bowl shading itself (labelled “Energy cut off area”), with Stine implying this shading in and of itself is undesirable.

[0006] Ultimately the solar bowl was not successful since the absence of a moving mirror and associated tracking cosine errors leads to low efficiency. “Tracking cosine error” means the aperture of the collector is not normal to the sun’s rays and hence less sunlight passes into the collector than the size of the collector should be capableof absorbing. Note more correctly that self-shading itself as demonstrated in Figure 1 is not the problem since all sunlight crossing the aperture opening is still collected, the problem is cosine error resulting in the projected area of the aperture to the sun being reduced, because the collector is tilted away from the sun.

[0007] One of the problems that has been identified with the FMDF solar bowl design for solar collectors is that since the mirror surface curvature is not very high (i.e. the bowl is shallow to minimise self-shading and water drainage problems), the normal self-stiffening of panels due to their inherent curvature is reduced which consequently results in the requirement for an extensive underlying support structure.

[0008] The shallow bowl in the FMDF solar bowl design requires the receiver structure centred at the centre of the spherical bowl be consequently large and high and therefore susceptible to wind loading. The FMDF solar bowl structure is also shaped to naturally collect water, hail and snow, and drainage in this configuration could be problematic. It is therefore desirable to provide an improved solar collector that addresses some of the shortcomings of the prior art.SUMMARY OF INVENTION

[0009] In an embodiment, there is provided a solar energy collection assembly comprising: a first spherical mirror assembly having a first reflective mirror surface with a centre located above the first spherical mirror, a radius of curvature R1 and a focus located on a first movable axis which passes through the centre of the first reflective mirror surface and through the sun with a first sunlight absorbing receiver adapted to be movably positioned to substantially align with the first movable axis in a plurality ofpositions for receiving and absorbing reflected light when sunlight is reflected by the first reflective mirror surface; a second spherical mirror assembly arranged above the reflective surface of the first spherical mirror assembly in a non-concentric configuration relative to the first spherical mirror assembly, the second spherical mirror having a second reflective mirror surface with a centre located away from the second spherical mirror, a radius of curvature R2 and a focus located on a second movable axis which passes through the centre of the second spherical mirror and through the sun with a second sunlight absorbing receiver adapted to be movably positioned to substantially align with the second movable axis in a plurality of positions for receiving and absorbing reflected light when sunlight is reflected by the second spherical mirror; and a rotation mechanism for rotating the combination of the first and second spherical mirror assemblies about a common axis to allow the reflective surface of the first and second spherical mirror assemblies to track the position of the sun through the day relative to that common axis.

[0010] In an embodiment, if the common axis is vertical then the sun tracking is azimuthal.

[0011] In an embodiment, the common axis is vertical and passes through the centre of the first reflective mirror surface of the first spherical mirror assembly.

[0012] In an embodiment, the first and second reflective surfaces meet to become joined and form a continuous surface having said first and second reflective surfaces, resulting in higher curvature mirror surfaces for the first and second reflective surfacesfor a given overall inclination relative to the underlying horizontal surface than if a single reflective surface was utilised.

[0013] In an embodiment, the first reflective mirror surface comprises a spherical portion with a reflective or non-reflective semi-circular prism portion extending from said spherical portion.

[0014] In an embodiment, the rotation mechanism of the solar energy collection assembly further comprises a generally cylindrical portion descending downwardly from the mirror assembly wherein the vertical axis of rotation for the spherical mirror assembly passes through a central vertical longitudinal axis of the cylindrical portion.

[0015] In an embodiment, the rotation mechanism of the solar energy collection assembly further comprises a bearing arrangement located at an in-use lower part of the cylindrical portion to enable rotational movement of the cylindrical portion.

[0016] In an embodiment, the first and second reflective surfaces are shaped to be tilted to allow the flow of liquid from one end of the first reflective surface under gravity thereby reducing accumulation of the rain, hail or snow within the reflective surfaces.

[0017] In an embodiment, the first receiver is adapted to pivot about a pivot point located at a distal end of the first receiver to allow the first receiver to align with the first movable axis in a plurality of positions.

[0018] In an embodiment, the second receiver is adapted to pivot about a pivot point located at a distal end of the second receiver to allow the second receiver to align with the second movable axis in a plurality of positions.

[0019] In an embodiment, opposed ends of the second receiver are movably mounted along respective arcuate tracks, said respective arcuate tracks being spaced apart to accommodate the second receiver therein, for allowing the second receiver to substantially align with the second movable axis in a plurality of positions.

[0020] In an embodiment, opposed ends of the first receiver are movably mounted along respective arcuate tracks, said respective arcuate tracks being spaced apart to accommodate the first receiver therein, for allowing the first receiver to substantially align with the first movable axis in a plurality of positions.

[0021] In an embodiment, the second spherical mirror assembly is arranged to be located above the first spherical mirror assembly such that at least a portion of the first spherical mirror assembly is shaded by the second spherical mirror assembly in at least one operable configuration with the sun low in the sky and wherein in a second operable configuration the first mirror assembly is more optimally inclined to receive sunlight with the sun being higher in the sky, when the second spherical mirror assembly is no longer in an optimal sunlight receiving position.

[0022] In an embodiment, the solar energy collection assembly further comprises an additional spherical sunlight collection assembly mounted adjacent the first or second spherical mirror assembly at a steeper inclination relative to said first or second mirror assemblies, the additional spherical sunlight collection assembly further comprising: an additional reflective mirror surface with a centre located away from the additional spherical mirror surface, a radius of curvature R3 and a focus located on a third movable axis which passes through the centre C3 of the additional spherical mirror and through the sun with a third sunlight absorbing receiver adapted to be movablypositioned to substantially align with the third movable axis in a plurality of positions for receiving and absorbing reflected light when sunlight is reflected by the additional spherical mirror.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:Figure 1 illustrates a solar collector from the prior art.Figures 2 to 4 illustrate various perspective views of a solar collector assembly 1000 in accordance with a preferred embodiment.Figure 5 illustrates isolated views of the spherical and cylindrical surfaces which form a part of the solar collector assembly 1000.Figure 6 illustrates an elevation view of the spherical and the cylindrical surfaces shown in Figure 5.Figure 7 illustrates various views of the spherical and cylindrical surfaces in a solar collector assembly 1000.Figure 8 illustrates various views of the spherical surfaces in a solar collector assembly 1000’ in accordance with an alternative embodiment.Figures 9 to 12 illustrate various views of the solar collector assembly 2000 which is a third alternative embodiment.DETAILED DESCRIPTION OF PREFERRED EMBODIMENTSFigures 2 to 7 illustrate a solar collector assembly 1000 in accordance with a preferred embodiment. The solar collector assembly 1000 comprises of two spherical mirror assemblies 100 and 200 respectively. The first spherical mirror assembly 100 comprises a larger surface area made from a first partial sphere 110 and a partial semi-circular prism 115 that forms a continuous surface. Specifically, the partial spherical portion 110 of the first spherical mirror assembly comprises the first reflective surface with a radius of curvature R1. The first spherical portion 110 comprises a centre C1 that is located above the spherical portion of the spherical mirror assembly 110. The first spherical portion 110 of the first spherical mirror assembly comprises a focal line that is located on a first movable axis which passes through the centre of the first spherical portion 110. A first receiver unit 120 is provided to be movably positioned to substantially align with the first movable axis in a plurality of positions or orientations for receiving and collecting light reflected by the first reflective surface of the spherical portion 110, and storing this collected light as heat. It would be understood that such an arrangement results in the first receiver unit 120 being oriented to maximise capture of any reflected sunlight reflected by the curved mirror surface of the spherical portion 110. The circular prism 115 may or may not be reflective, and may or may not be used to capture sunlight in any way. In this preferred embodiment it is not reflective, slopes downwards, and is hence used a roofing membrane. The first spherical mirror assembly 100 is shaded from sunlight by 200 when the sun is low in the sky, with 200 serving as a secondary solar collecting assembly.

[0024] The presently described solar collector assembly 1000 uses the combination of the first spherical mirror assembly 100 in tandem with a second spherical mirror assembly 200 in a novel configuration to address some of the shortcomings of the prior art. The second spherical mirror assembly 200 is arranged above and in front of the first solar collector assembly 100 and comprises a second partial spherical portion 210 with a reflective surface. As evident from Figures 2 to 7, the second spherical portion comprises a radius of curvature R2 which may or may not be the same size as the radius of curvature R1 for the first spherical portion 110. Importantly, the second spherical portion 210 is arranged in a non-concentric and tilted configuration relative to the first spherical portion 110, with 200 being tilted to efficiently collect sunlight with the sun low in the sky (i.e. steeper inclination relative to a horizontal surface), and 100 tilted to efficiently collect sunlight with the sun high in the sky (i.e. shallower inclination relative to a horizontal surface). The second spherical portion 210 also includes a centre C2 that is located away from the reflective surface of the second spherical portion 210 and forward of the centre C1 . The second spherical mirror assembly 200 includes a focal line located on a second movable axis which passes through the centre C2 of the second spherical portion 210 and through the sun, with a second receiver 220 adapted to be movably positioned to substantially align with the second movable axis in a plurality of positions for receiving and collecting light from reflected sunlight that is reflected by the second spherical mirror of the second spherical portion 210 during use, and storing this collected light as heat.

[0025] Each of the sunlight absorbing receivers 120 and 220 may be adapted for absorbing heat from the concentrated reflected light received by the receiver 120 and 220, for example storing heat in a molten salt module. This heat could then be furthertransmitted to a remote location. The receiver may also take a variety of other forms to utilize the reflected sunlight. The receiver could for instance take the concentrated sunlight and direct it into a waveguide (light-pipe) that could transmit it inside a building. The receiver could be an array of photovoltaic cells which then transform the concentrated photons into electricity and heat. The receivers 120 and 120 could be secondary concentrators and receivers for further concentration.

[0026] The first and second spherical mirror assemblies are fixedly inclined to each other. As a result, in the currently described embodiment, the inclination of the second spherical portion 210 relative to the first spherical portion 110 is fixed and cannot be varied. However, in further embodiments, an alternative arrangement may be provided which may allow the inclination of the second spherical portion 210 (relative to the first spherical portion 110) to be varied to maintain a plurality of orientations each of those orientations resulting in the second spherical portion 210 being non -concentric and tilted relative to the first spherical portion. The non-concentric arrangement of the first and second spherical mirror assemblies 100 and 200 may or may not imply that the respective centres C1 and C2 lie at different vertical elevations, for the embodiment shown in Figures 2 to 7, C1 and C2 were set at different heights because this allowed the slope of 115 for water drainage.

[0027] A rotation mechanism 300 is also provided for rotating the combination of the first and second spherical mirror assemblies 100 and 200 about a vertical axis, that is azimuthally. A generally cylindrical wall 310 descends downwardly from the peripheral portions of the first spherical mirror assembly 100. The cylindrical wall 310 effectively provides a support structure for supporting the combination of the first spherical mirror assembly 100 and the second spherical mirror assembly 200. The lower end portionsof the cylindrical wall 310 are provided with bearings to enable rotation of the cylindrical wall 310 which allows for rotation of the combination of the first and second spherical mirror assemblies along a generally central vertical axis of the cylindrical walls to allow the reflective surfaces of the first and second spherical mirror assemblies 100 and 200 to be directed azimuthally towards the sun during use. Preferably, the vertical axis of rotation also passes through the centre C1 of the first spherical portion 110 of the first spherical mirror assembly 100. Any suitable rotation mechanism may be utilized without departing from the spirit and scope of the invention.

[0028] The inclination of the second spherical mirror assembly 200 avoids accumulation of any rainwater, hail or snow on the reflective mirror surface of the spherical portion 210 and results in the flow of any rainwater, hail or snow under gravity towards a sloping semi-circular prism 115 section ofthe first spherical mirror assembly100. Rainwater, hail or snow also flows down from the first spherical mirror assembly100 onto a sloping peripheral portion of the semi-circular prism section 115 underlying the first spherical mirror assembly 100.

[0029] The combination of the multiple spherical mirror assemblies 100 and 200 in combination with an underlying cylindrical rotation mechanism 300 allows the solar collector assembly 1000 to be integrated onto an existing rooftop of a building structure. The novel configuration of the solar collector assembly 1000 provides strong shading and water shedding. Unlike some of the currently known prior art solar collectors for rooftops, the aforementioned novel configuration reduces accumulation of rainwater, hail and snow.

[0030] The use of a duality of spherical mirror assemblies 100 and 200 in a non- concentric configuration which rotates about a vertical axis on an underlying cylindricalsupport structure 300 results in higher level of solar collection. The multiple receiving units being positioned at lower heights because of high mirror curvature reduces risks associated with high wind loading.

[0031] The first spherical mirror assembly 100 collector is the same or close to the same diameter as the circular roof that the collector forms in this example, which allows a smaller radius / high curvature reflector, hence low height receiver and strong self-stiffening of the reflector surface.

[0032] Referring to Figure 6 in particular it is clear that in at least some implementations, the first spherical portion 110 may be oriented to be suitable for capturing sunlight from the high sun position, that is low inclination to the horizontal, during which no, or almost no shading occurs from 200. The second spherical portion 210 which is in the non-concentric and tilted configuration may be oriented to substantially to capture sunlight from the low sun position, that is high inclination to the horizontal. There is shading of the first collector 100 in such a configuration. Even though there is shading in the low sun position, the combined sunlight captured throughout the day is greater than if 200 was removed. The overall approximate inclination of the first and second reflective surfaces relative to the underlying horizontal surface is denoted by A in Figure 6. ASUN-LOWdenotes a first overall approximate inclination when the sun is in a low position. ASUN-HIGHdenotes an overall approximate inclination when the sun is in a higher position.

[0033] Referring to Figure 5, the first spherical mirror assembly 100 is the rearmost bowl and is formed from a portion of a sphere 110 coupled with a portion of a semi- circular prism 115. The semi-circular prism section 115 of the first spherical mirror assembly 100 serves as a roof portion allowing free drainage of water from the roof.The second spherical mirror assembly 200 is the front-most bowl and shades the spherical portion 110 of the first spherical mirror assembly 100 until the sun is high. The steep inclination angle of the second spherical mirror assembly 200 maximises collection of sunlight in the early morning and late afternoon. The second spherical mirror assembly 200 being forwardly positioned implies that any undesirable rearwards shading by the whole collector assembly in the low sun position beyond or behind the collector is minimized.

[0034] Figure 6 illustrates how the non-concentric and inclined configuration of the second spherical collector assembly 200 relative to the first spherical collector assembly 100 provides a geometric configuration that allows water drainage from the second spherical mirror assembly 200, on to the sloping semicircular prism section 115 of the first spherical mirror assembly 100, and then off the complete collector assembly 1000.

[0035] Figure 7 illustrates how the second spherical mirror assembly could be installed such that the upper most portion of the inclined spherical portion 210 of the second spherical mirror assembly can be as high as the pivot point C1 of the first receiver unit 120, and this allows the receiver 120 pivot support to also support the second spherical mirror assembly 200.

[0036] The solar collector 1000 can be modified to include additional collectors (say a third collector), as well as the collector centres being offset by height.

[0037] Figures 8 illustrates a second embodiment of the solar collector 1000' assembly in accordance with another preferred embodiment. It is important to note that in Figure8 only the mirror assemblies are shown for clarity, with no receiver assemblies or mechanism to track the sun along one axis. The receiver assemblies 120 and 220 may be adopted for the second embodiment. This embodiment assumes azimuthal tracking of the sun throughout the day, that is about a vertical axis. The second spherical mirror assembly 200' with radius R2 joins the first spherical mirror assembly 100’ with radius R1 . The centres of C1 and C2 are where the receivers (not shown) pivot. The second spherical assembly 200' is substantially a portion of a spherical mirror surface. As shown in Figure 8, the first spherical assembly 100' is inclined downwardly from the second spherical assembly 200’. It can clearly be seen that such a joined configuration using the first and second spherical mirror assemblies, creates a steeper overall approximate inclination A in Figure 8 to the horizontal for the whole collector assembly compared with the normal FMDF solar bowl arrangement, as well as smaller radii of curvature for each spherical assembly and hence greater self-stiffening. Depending on the latitude this increased inclination for the whole mirror assembly, when tracked azimuthally may result in more optimum year-round sunlight collection. The connection of the two mirror spherical surfaces seals the mirror assembly allowing it to function as a roof, and the geometry shown always slopes downwards to drain water. The letter A once again denotes the overall approximate inclination of the first and second reflective surfaces relative to the underlying horizontal surface.

[0038] Solar collector 2000 shown in Figures 9 to 12 illustrates a modification of the previously described embodiment 1000’, in accordance with a third preferred embodiment featuring three spherical surfaces and three receivers. Functionally this acts similarly to the second embodiment 1000’ but the use of three surfaces allows a shallower bowl if this is desired depending on how the mirrors are truncated. Figures9 to 12 illustrate the inclusion of the third spherical mirror assembly 400” in addition tofirst and second spherical mirror assemblies 100" and 200". Like reference numerals denote like features that have been previous described. It is also possible for instance to offset the additional collectors laterally. The vertical or lateral shifting of the collector centres (i.e. receiver pivot positions) would be used if necessary to avoid interference between receivers for the low sun position and to guarantee that water will consistently drain from the collector. Each spherical mirror assembly may be provided with its individual receiving unit 120, 220 and 420.

[0039] Review of the dual and triple element bowls shown in the solar collectors 1000’ and 2000 described above show that the spherical mirror assemblies have overall inclination angles of around 35°, though this could be reduced somewhat by truncating the rear lip of the bowl at a different height. Reduction of this overall approximate inclination angle is desirable for spherical mirror assemblies in solar collectors operating closer to the equator to allow collection of the maximum amount of sunlight (because the sun is higher in summer close to the equator, and can be over vertical in the tropics), and allows significantly easier building integration for bowls being used as roof cladding. Reduction of the overall approximate inclination angle also reduces the shade the bowl creates behind the final structure, and this undesirable shading is magnified by the large height of the bowls described above.

[0040] Reduction of the inclination angle for the second and third embodiment does however compromise the bowl collecting sunlight in the low sun position (i.e. early morning and late afternoon). The use of two or more integrated spherical mirror assemblies 100 and 200 as was done in embodiment 1000, with an acceptance of self-shading, can create a solar collector configuration that is much easier toincorporate as a roof because it has lower practical inclination, has limited undesirable rear shading, is more efficient at collecting sunlight in the low sun position, and is not disadvantaged in the high position. The aforementioned configuration 1000 maximises self-shading of the rear spherical assembly 100 but largely minimizes cosine errors for the whole collector assembly. The plan-view of such spherical mirror assemblies can still be circular as per all the spherical mirror assemblies described in the Detailed Description, and hence most suitable for rotation about a vertical axis as a full assembly.

[0041] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term “comprises” and its variations, such as “comprising” and “comprised of’ is used throughout in an inclusive sense and not to the exclusion of any additional features.

[0042] It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect.

[0043] The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Claims

CLAIMS1. A solar energy collection assembly comprising: a first spherical mirror assembly having a first reflective mirror surface with a centre located above the first spherical mirror, a radius of curvature R1 and a focus located on a first movable axis which passes through the centre of the first reflective mirror surface and through the sun with a first sunlight absorbing receiver adapted to be movably positioned to substantially align with the first movable axis in a plurality of positions for receiving and absorbing reflected light when sunlight is reflected by the first reflective mirror surface; a second spherical mirror assembly arranged above the reflective surface of the first spherical mirror assembly in a non-concentric configuration relative to the first spherical mirror assembly, the second spherical mirror having a second reflective mirror surface with a centre located away from the second spherical mirror, a radius of curvature R2 and a focus located on a second movable axis which passes through the centre of the second spherical mirror and through the sun with a second sunlight absorbing receiver adapted to be movably positioned to substantially align with the second movable axis in a plurality of positions for receiving and absorbing reflected light when sunlight is reflected by the second spherical mirror; and a rotation mechanism for rotating the combination of the first and second spherical mirror assemblies about a common axis to allow the reflective surface of the first and second spherical mirror assemblies to track the position of the sun through the day relative to that common axis.

2. A solar energy collection assembly in accordance with claim 1 wherein if the common axis is vertical then the sun tracking is azimuthal.

3. A solar energy collection assembly in accordance with claim 2 wherein the common axis is vertical and passes through the centre of the first reflective mirror surface of the first spherical mirror assembly.

4. A solar energy collection assembly in accordance with any one of the preceding claims wherein the first and second reflective surfaces meet to become joined and form a continuous surface having said first and second reflective surfaces resulting in higher curvature mirror surfaces for the first and second reflective surfaces for a given overall inclination relative to the relative underlying horizontal surface than if a single reflective surface was utilised.

5. A solar energy collection assembly in accordance with any one of the claims 1 to 3 wherein the first reflective mirror surface comprises a spherical portion with a reflective or non-reflective semi-circular prism portion extending from said spherical portion.

6. A solar energy collection assembly in accordance with any one of the preceding claims wherein the rotation mechanism further comprises a generally cylindrical portion descending downwardly from the mirror assembly wherein the vertical axis of rotation for the spherical mirror assembly passes through a central vertical longitudinal axis of the cylindrical portion.

7. A solar energy collection assembly in accordance with claim 6 wherein the rotation mechanism further comprises a bearing arrangement located at an in-uselower part of the cylindrical portion to enable rotational movement of the cylindrical portion.

8. A solar energy collection assembly in accordance with any one of the preceding claims wherein the first and second reflective surfaces are shaped to be tilted to allow the flow of liquid from one end of the first reflective surface under gravity thereby reducing accumulation of the rain, hail or snow within the reflective surfaces.

9. A solar energy collection assembly in accordance with any one of the preceding claims wherein the first receiver is adapted to pivot about a pivot point located at a distal end of the first receiver to allow the first receiver to align with the first movable axis in a plurality of positions.

10. A solar energy collection assembly in accordance with any one of the preceding claims wherein the second receiver is adapted to pivot about a pivot point located at a distal end of the second receiver to allow the second receiver to align with the second movable axis in a plurality of positions.

11. A solar energy collection assembly in accordance with any one of the preceding claims wherein opposed ends of the second receiver are movably mounted along respective arcuate tracks, said respective arcuate tracks being spaced apart to accommodate the second receiver therein, for allowing the second receiver to substantially align with the second movable axis in a plurality of positions.

12. A solar energy collection assembly in accordance with any one of the preceding claims wherein opposed ends of the first receiver are movably mounted along respective arcuate tracks, said respective arcuate tracks being spaced apart toaccommodate the first receiver therein, for allowing the first receiver to substantially align with the first movable axis in a plurality of positions.

13. A solar energy collection assembly in accordance with any one of claims 1 to 3 or claims 5 to 12 wherein the second spherical mirror assembly is arranged to be located above the first spherical mirror assembly such that at least a portion of the first spherical mirror assembly is shaded by the second spherical mirror assembly in at least one operable configuration with the sun low in the sky and wherein in a second operable configuration the first mirror assembly is more optimally inclined to receive sunlight with the sun being higher in the sky, when the second spherical mirror assembly is no longer in an optimal sunlight receiving position.

14. A solar energy collection assembly in accordance with any one of claims 1 to 4 or claims 6 to 12 comprising an additional spherical sunlight collection assembly mounted adjacent the first or second spherical mirror assembly at a steeper inclination relative to said first or second mirror assemblies, the additional spherical sunlight collection assembly further comprising: an additional reflective mirror surface with a centre located away from the additional spherical mirror surface, a radius of curvature R3 and a focus located on a third movable axis which passes through the centre C3 of the additional spherical mirror and through the sun with a third sunlight absorbing receiver adapted to be movably positioned to substantially align with the third movable axis in a plurality of positions for receiving and absorbing reflected light when sunlight is reflected by the additional spherical mirror.