Solar unit assembly and a method for constructing such an assembly

Abstract

The present invention relates to a solar unit assembly adapted for reflecting light onto a receiver, comprising a plurality of solar collector units, a primary support element, a plurality of secondary support elements, and two side support elements. The invention furthermore relates to a method of providing such a solar unit assembly.

Claims

1. A solar unit assembly comprising: a plurality of solar collector units having the same width arranged in at least one row, a receiver, a primary support element, a plurality of secondary support elements, and two side support elements, each solar collector unit comprising a flexible reflector element and a support structure supporting said reflector element and said support structure comprising a predefined number of profiles per length unit, in which the plurality of solar collector units defines a longitudinal direction and an arcuate direction, wherein the receiver is connected to the primary support element, that the primary support element is attached solely to the first row of one or more solar collector units extending in the longitudinal direction and to the side support elements, and that the plurality of secondary support elements are attached solely to the remaining row or rows of one or more solar collector units in the longitudinal direction and to the side support elements, wherein the primary support element includes two end sections and is substantially rectangular in cross-section, and wherein the primary support element includes four beams extending in the longitudinal direction between the end sections.

2. A solar unit assembly according to claim 1, wherein the primary support element furthermore includes one or more intermediate sections and a number of stay elements extending between an end section and an intermediate section and/or between intermediate sections.

3. A solar unit assembly according to claim 1, wherein the primary support element is provided with engagement means adapted to cooperate with a respective side support element, preferably in the form of flanges provided on the respective end section.

4. A solar unit assembly according to claim 1, wherein each secondary support element includes two end sections and is substantially triangular in cross-section.

5. A solar unit assembly according to claim 4, wherein each secondary support element includes one beam forming an apex beam and two beams forming base beams, the base beams being adapted to face the solar collector panel in the installed condition.

6. A solar unit assembly according to claim 4, wherein the secondary support element furthermore includes one or more intermediate sections and a number of stay elements extending between an end section and an intermediate section and/or between intermediate sections-.

7. A solar unit assembly according to claim 4, wherein the secondary support element is provided with engagement means adapted to cooperate with a respective side support element, preferably in the form of flanges provided on the respective end section.

8. A solar unit assembly according to claim 1, wherein each side support element comprises at least one arcuate beam, and one primary engagement member adapted to cooperate with the primary support element and a set of secondary engagement members adapted to cooperate with a respective secondary support element.

9. A solar unit assembly according to claim 8, wherein the primary engagement member includes a rectangular beam structure and four flanges.

10. A solar unit assembly according to claim 8, wherein each secondary engagement member includes a triangular beam structure and three flanges.

11. A solar unit assembly according to claim 1, wherein the primary support element has a torsional strength and bending resistance that are substantially larger than that of each secondary support element.

12. A solar unit according to claim 11, wherein the ratio of the torsional strength and bending resistance of the primary support element and the secondary support element is in the range of 1.5:1 to 3:1.

13. A solar unit according to claim 11, wherein the torsional strength and bending resistance of the primary support element is at least two times the corresponding values for the secondary support element.

14. A solar unit assembly according to claim 1, wherein the number of rows lies in the interval 2 to 11.

15. A solar unit assembly according to claim 1, wherein the number of rows lies in the interval 5 to 9.

16. A method of constructing a solar unit assembly, comprising the steps of: a) forming a plurality of solar collector units each being provided by the steps of providing a substrate, providing a reflective surface on the substrate to form a reflector element, providing a support structure comprising a predefined number of profiles, adapting the shape of the reflector element, and fixing the shape of the reflector element by connecting the support structure to the reflector element to provide a solar collector unit; b) providing a primary support element, a plurality of secondary support elements and two side support elements, c) connecting the side support elements on a grounded element, such as a concrete foundation mounted with pylons; d) connecting the primary support element to the side support elements; e) connecting the plurality of secondary support elements to the side support elements; f) attaching a first plurality of solar collector units to the primary support element in a first row in order to cover the full length of the primary support element in a longitudinal direction; and g) attaching a second plurality of solar collector units to the plurality of secondary support elements in order to cover the full length of the secondary support elements and to define an arcuate direction; to provide the solar unit assembly, wherein the solar unit assembly comprises: a plurality of solar collector units having the same width arranged in at least one row, a receiver, a primary support element, a plurality of secondary support elements, and two side support elements, each solar collector unit comprising a flexible reflector element and a support structure supporting said reflector element and said support structure comprising a predefined number of profiles per length unit, in which the plurality of solar collector units defines a longitudinal direction and an arcuate direction, wherein the receiver is connected to the primary support element, that the primary support element is attached solely to the first row of one or more solar collector units extending in the longitudinal direction and to the side support elements, and that the plurality of secondary support elements are attached solely to the remaining row or rows of one or more solar collector units in the longitudinal direction and to the side support elements, and wherein the primary support element includes two end sections and is substantially rectangular in cross-section, and wherein the primary support element includes four beams extending in the longitudinal direction between the end sections.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following the invention will be described in further detail by means of examples of embodiments with reference to the schematic drawings, in which

(2) FIG. 1 shows a perspective view of an embodiment of a solar unit assembly according to the invention;

(3) FIG. 2 shows a perspective view of the solar unit assembly of FIG. 1 from another angle;

(4) FIG. 3 shows a side view of the solar unit assembly of FIGS. 1 and 2;

(5) FIG. 4 shows a partial perspective view, on a larger scale, of a detail of the solar unit assembly of FIGS. 1 to 3, namely the primary support element connected to a solar collector unit of a first row;

(6) FIG. 5 shows a partial side view of the detail of FIG. 4;

(7) FIGS. 6 and 7 show views corresponding to FIGS. 4 and 5, respectively, of another detail of the solar unit assembly, namely the secondary support element connected to a solar collector unit of a second row;

(8) FIG. 8 shows a perspective view of the side support element;

(9) FIGS. 9 and 10 show perspectives of the primary and secondary support elements respectively;

(10) FIGS. 11-14 show partial perspectives of details of the support structures on a larger scale; and

(11) FIG. 15 is a perspective view corresponding to FIG. 1 illustrating a method of constructing the assembly.

DETAILED DESCRIPTION

(12) In the drawing, an embodiment of a solar unit assembly 1 according to the invention is shown. The assembly 1 typically forms part of a solar energy plant including energy generation and storage means, control systems etc, not shown. Referring in particular to FIG. 1, the assembly 1 includes a plurality of solar collector units 2 mounted on a carrying or support frame including a primary support element 5, a plurality of secondary support elements 6 and a side support element 7 at each longitudinal end of the assembly 1.

(13) In the configuration shown, the assembly 1 includes a total of 21 solar collector units 2 of which seven solar collector units 2 are positioned in juxtaposition to each other in an arcuate direction, a, projecting on a width and height direction, y, z, and three solar collector units 2 in a longitudinal direction, x.

(14) In the following, only one solar collector unit 2 will be described in detail; other solar collector units of a plant may be designed in a similar or modified manner. It is also to be understood that a single solar collector unit 2 may constitute a solar energy plant in itself, for instance for the household field of use. Furthermore, the solar collector unit may also be used as a repair unit. Each solar collector unit 2 is produced to have a predefined parabolic shape. In the embodiment shown, each solar collector unit 2 includes a reflector element 21 formed by a substrate and a reflective surface provided on the substrate, said reflective surface may be a high reflective film from 3M (such as 3M SMF 1.100 films) or ReflecTech mirror films, and said solar collector element further including a support structure generally comprising a predefined number of profiles 22 connected to the reflector element at a distance from each other, cf. FIGS. 11 and 13, preferably the number of profiles per 2000 mm is 3 to 12, more preferred 4 to 10 and even more preferred 5 to 8. The profiles serve to ensure the parabolic nature of the solar collector units Details regarding the construction of the solar collector units 2 are the subject of Applicant's international application No. PCT/DK2012/050308. Generally, the solar collector units 2 have an average weight of app. 5 Kilos per square meter.

(15) In the focus line of the parabola, a receiver 4 is arranged and mounted to the carrying or support frame of the assembly 1 by means of holding arms 3. The receiver 4 is adapted to accommodate a heat transfer fluid, such as water for consumption or for evaporation, in a manner known per se.

(16) The entire solar collector unit 2 is connected to carrying frame 1 either by mechanical or adhesive means, or by a combination. Suitable adhesive connections include the use of for instance 3M Scotch-Weld 7271 B/A. Mechanical connection is also conceivable and may for instance include clamping devices. Furthermore, the solar collector units may be connected to each other in any suitable manner.

(17) In the following, the construction of the elements forming part of the carrying or support frame will be described in detail.

(18) Thus, the receiver 4 is connected to the primary support element 5, thus at the position giving the maximum protection against torsion and bending that might otherwise bring the receiver out of alignment.

(19) In turn, the primary support element 5 is attached solely to the first row of one or more solar collector units 211, 212, 213 extending in the longitudinal direction and to the side support elements 7.

(20) In the remaining rows of solar collector units 221, 222, 223; 231, 232, 233 . . . 271, 272, 273, one secondary support element 6 is attached to a respective row of one or more solar collector units and to the side support elements 7 as is illustrated i.a. in FIG. 15.

(21) In order to withstand the demands to torsional strength and resistance to bending, the primary support element 5 is of a robust structure. In the embodiment shown, the primary support element 4 includes two end sections 50 and is substantially rectangular in cross-section, in that four beams 51 extend in the longitudinal direction between the end sections 50. The primary support element 5 is reinforced by one or more intermediate sections 56 and a number of stay elements 51, 52, 53, 54 extending between one end section 50 and the adjacent intermediate section 56 and between the intermediate sections 56. In order to provide connection to the side support element 7 at either longitudinal side, the primary support element 5 is provided with engagement means adapted to cooperate with a respective side support element 7, in the embodiment shown in the form of flanges 57 provided on the respective end section 50, as shown in FIG. 12. The elements are connected to each other by any suitable means, for instance bolts or clamping devices.

(22) The length of the primary support element 5 is adapted to the total length of the solar collector units 211, 212, 213 of the first row. In the actual embodiment, each solar collector unit has a uniform length of approximately 4 m and an arcuate dimension of approximately 1.3 m, and hence, the length of the primary support element 5 is approximately 12 m. At this length, the weight of the primary support element 5 is approximately 500 kg.

(23) As to the secondary support element 6, it includes two end sections 60 and is substantially triangular in cross-section. The triangular cross-section is obtained in that each secondary support element 6 includes one beam 61 forming an apex beam and two beams 62 forming base beams, the base beams 62 being adapted to face the solar collector panel 221 in the installed condition, cf. FIG. 13. Sufficient strength is obtained, in the embodiment shown, in that secondary support element 6 furthermore includes one or more intermediate sections 66 and a number of stay elements 63, 64, 65 extending between the end sections 60 at either end, and the adjacent intermediate section 66, and between intermediate sections 66. Connection to the side support elements 7 at either side is obtained in that the secondary support element 6 is provided with engagement means adapted to cooperate with a respective side support element 7, here in the form of flanges 67 provided on the respective end section 60. As for the primary support element 5, the elements are connected to each other by any suitable means, for instance bolts or clamping devices.

(24) The length of the secondary support elements 6 is adapted to the total length of the solar collector units 221, 222, 223 of the second row and in any further rows. In the actual embodiment, the length of each primary support element 6 is approximately 12 m. At this length, the weight of the secondary support element 6 is approximately 200 kg. It is contemplated that the secondary elements may have other suitable dimensions such as the same dimension as the primary support element. However, the triangular structure is preferred since the weight of the total structure is reduced and this without compromising the stability and precision of the final unit.

(25) The length of the primary and secondary support elements 5, 6, i.e. approximately 12 m, provides a good compromise between ease of installation with few parts and manageable length. A length of 12 m will thus be able to be transported by usual means, such as lorries and containers. However, the length may be any suitable length and the invention should not be limited to the length illustrated.

(26) In order to provide for easy and reliable connection between the longitudinally extending primary and secondary support elements 5, 6 and the side support elements 7, each side support element 7 includes, in the embodiment shown, at least one, here two, arcuate beams 71, 72, and one primary engagement member 73, 74 adapted to cooperate with the primary support element 5 and a set of secondary engagement members 75, 76 adapted to cooperate with a respective secondary support element 6. Referring in particular to FIG. 8, and to FIGS. 11 and 13, respectively, the primary engagement member includes a rectangular beam structure 73 and four flanges 74, and each secondary engagement member includes a triangular beam structure 75 and three flanges 76. Furthermore, each side support element 7 is provided with an upstanding plate element 77 adapted to provide connection to the outermost holding arms 3 supporting the receiver 4. The holding arms 3 are mounted directly to the primary support element 5.

(27) Due to the optimized structure of the carrying or supporting frame, the primary support element 5 should have a torsional strength and bending resistance that are substantially larger than that of the secondary support element(s) 6, for instance in the range 1.5:1 to 3:1, preferably 2:1, for instance at least two times the corresponding values for the secondary support element 6.

(28) By this structure, it is possible to increase the number of rows of the solar unit assembly. With traditional structures, the rows will most often be limited to three, four or five, thus setting an upper limit of the span, the overall area of reflecting surface per length unit, and consequently on the energy concentrated in the receiver 4. Depending on the field of application of the solar unit assembly, the number of rows lies in the interval 2 to 11, preferably 5 to 9, such as 5, 6, 7, 8 or 9. The larger number of solar collector units, thus here 21 solar collector units over a length of only 12 m, makes it possible to either provide shorter plants, or to increase the temperature of the heat transfer fluid inside the receiver 4, for instance even up to 450 or 550 C., which makes it possible to increase the efficiency of systems downstream from the solar unit assembly in such a plant.

(29) The construction of the solar unit assembly may in principle take place in any suitable manner and order of steps. A preferred method, however, comprises the steps of: a) forming a plurality of solar collector units each being provided by the steps of: providing a substrate, providing a reflective surface on the substrate to form a reflector element, providing a support structure comprising a predefined number of profiles, adapting the shape of the reflector element, and fixing the shape of the reflector element by connecting the support structure to the reflector element to provide a solar collector unit,

(30) b) providing a primary support element 5, a plurality of secondary support elements 6 and two side support elements 7, c) connecting the side support elements 7 on a grounded element, such as a concrete foundation mounted with pylons; d) connecting the primary support element 5 to the side support elements 7; c) connecting the plurality of secondary support elements 6 to the side support elements 7; f) attaching a first plurality of solar collector units to the primary support element 5 in a first row in order to cover the full length of the primary support element in a longitudinal direction; g) attaching a second plurality of solar collector units to the plurality of secondary support elements 6 a second, third, fourth etc. row in order to cover the full length of the secondary support elements and to define an arcuate direction; to provide the solar unit assembly.

(31) It is contemplated that the order of the steps e) and f) can be reversed so that the solar collector units are attached to the first support structure before the secondary support structures are attached.

(32) It is also contemplated that additional rows of secondary support structures and corresponding solar collector units may be added after an initial construction of a solar unit assembly so that the capacity can be increased if desired. Increasing the number of secondary support structures and corresponding solar collector units does not compromise the stability of the structure neither does it mitigate the precision and accuracy of the reflection. Rather, the addition of additional rows of secondary structures increases the efficiency and hence the temperature of the fluid.

(33) The individual parts of the solar unit assembly can be flexibly assembled at any site in order to optimize the manufacture and transportation of the parts constituting the assembly.

(34) Since each element is very light and the assembling is very simple it is possible to build up to 500.000 m.sup.2 solar fields in less than a year using only a small team of workers using forklifts.

(35) Each solar unit assembly may stand alone or form part of a larger solar unit plant. Due to the design of each solar unit assembly they can be individually controlled e.g. by electrical engines to hold each assembly in the correct position.