solar collectors

Abstract

A solar collector with a support is described, which has supporting sections arranged side by side, which are fixed to adjacent surfaces (2) arranged on both sides of the support (1) and consist of an open plastic shell (3), the supporting section having side edge flanges (17) with a predetermined parabolic groove for accommodating a reflector section (16) and a central rib (8) protruding from the shell bottom (7) starting from the adjacent side end face, which forms a reflector support surface (18) following the direction of the parabolic groove. In order to ensure good shape stability, it is proposed that the central rib (8) ends before the outlet side end face opposite to the adjacent side end face, at least one side rib (11) protrudes from the shell bottom (7) between the central rib (8) and the side shell wall (10), the at least one side rib (11) starts from the continuous end wall (9) of the outlet side end face and ends before the adjacent side end face, and forms a reflector support surface (18) following the direction of the parabolic trough, and the side shell wall (10) protruding from the shell bottom (7) and the wall (12) of the central rib (8) form a stepped shoulder (13).

Description

Technical Field

[0001] The present invention relates to a solar collector with a bracket, which has support sections arranged side by side, which are fixed on adjacent surfaces arranged on both sides of the bracket and are composed of an open plastic shell. The support section has side edge flanges with a predetermined parabolic groove for accommodating the reflector section, and a central rib protruding from the shell bottom starting from the adjacent side end surface, which forms a reflector support surface that follows the direction of the parabolic groove. Technical Field

[0003] In order to make full use of solar energy in an advantageous manner, a solar collector in the form of a parabolic trough with an absorber tube in the focal axis is known. In order to arrange the reflector segment in accordance with the parabolic trough shape and to be able to track the position of the sun around the longitudinal axis parallel to the trough profile of the trough, the support frame is usually provided with a bracket forming a pivot, on which are fixed support segments for accommodating the reflector, which are arranged side by side in the direction of the bracket and protrude on both sides and have a predetermined trough profile. The thin-walled reflector segment therefore only needs to be connected to the support segment under corresponding elastic deformation. In order to ensure a light structure without having to give up sufficient stability and shape accuracy of the solar collector, (WO2013 / 087477A1) has suggested that the support segment be formed as a plastic shell open to the reflector segment, which forms an annular edge flange for accommodating the reflector segment. To ensure the dimensional stability of the mirror segments under the expected wind loads, the channel-shaped plastic shell is equipped with an additional central rib, whose depth decreases with increasing distance from the support, according to the load curve. This additional central rib provides further support for the mirror segments between the edge flanges. This central rib is also equipped with transverse grooves in the support surface to increase the torsional stiffness of the support segment. Despite these measures, the higher requirements for dimensional stability, especially at a relatively low weight, are still not met. Summary of the Invention

[0004] The object of the present invention is therefore to create favorable conditions for a dimensionally stable solar support structure consisting of thin-walled reflector segments which are arranged alongside one another along a support to form a parabolic trough.

[0005] Based on the solar collector of the type mentioned at the beginning, the technical problem solved by the present invention is that the central rib ends before the outlet side end face opposite to the adjacent side end face, and at least one side rib protrudes from the shell bottom between the central rib and the side shell wall. The side rib starts from the continuous end wall of the outlet side end face and ends before the adjacent side end face, forming a reflector support surface following the direction of the parabolic trough, and the side shell wall protruding from the shell bottom and the wall of the central rib form a stepped shoulder.

[0006] While the ribs projecting from the shell base—the central rib and at least two side ribs—are necessary for the plastic shell's load-bearing capacity, they are insufficient to ensure the required flexural and torsional rigidity for the desired dimensional stability under the expected high loads, particularly those caused by wind. These high resistance to deformation is surprisingly achieved by combining additional end-side arm sections of the ribs, which terminate before the respective opposing plastic shell end faces and are offset relative to one another, with stepped shoulders in the plastic shell's side walls and the walls of the central rib. That is, given a relatively small and uniform plastic shell wall thickness, the side ribs, in particular, begin at the outlet-side end face, continuously supporting the reinforced end wall of the plastic shell. Because the ribs projecting from the shell base not only create a high resistance to deformation of the plastic shell that could damage the trough profile, but also provide an additional support surface for the reflector segment that follows the path of the parabolic trough, the support segment according to the invention allows the use of thin reflector segments that remain elastically pressed against the support segment that predefines the parabolic trough.

[0007] Particularly favorable design conditions are achieved if the central rib tapers from the adjacent end face of the plastic shell and the side ribs taper from the outlet-side end wall, so that the rib walls extending converging toward one another improve, in particular, the transverse stiffness. Furthermore, if the ribs taper correspondingly from the opposing end faces of the plastic shell, they can be arranged in a more space-saving manner.

[0008] By means of the measure that the stepped shoulders of the side shell walls and the walls of the central rib form a stepped bottom section with a continuously decreasing setback height toward the outlet-side end face and that the side ribs protrude from the stepped bottom section, it can be easily taken into account that the groove-shaped plastic shell has a smaller depth with increasing distance from the support in accordance with the load variation curve, so that due to the shoulders leading to the outlet-side end face of the plastic shell (German: auslaufenden), the side ribs can be designed with a height that is sufficient for the corresponding resistance torque also in the area of ​​the outlet-side end face of the plastic shell.

[0009] Although one side rib on each side of the central rib is sufficient for certain applications, if high wind loads must be taken into account, it is expedient to provide two side ribs between the central rib and the side shell walls.

[0010] The efficiency of a solar collector with a parabolic trough-shaped reflector depends on maintaining the parabolic shape and its orientation relative to the absorber tube, which extends parallel to the support of the support segment. If the support segment has a stop angle on the adjacent side end face that positively spans the orientation stop of the support, the predetermined parabolic shape of the plastic shell of the support segment can be easily and precisely aligned relative to the support and, therefore, the absorber tube, because the support segment only needs to be suspended at its stop angle by resting on the lateral adjacent surface of the support to ensure the desired orientation. The support segment then only needs to be connected to the support in a more rigid manner, for example, by pressing the stop angle on the orientation stop and screwing it to the adjacent surface of the support. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings illustrate the subject matter of the invention. In the drawings:

[0012] Figure 1 A top view of the support section according to the invention fastened to the support,

[0013] Figure 2 Shown on a larger scale along Figure 1 The support section in the cross section along the cutting line II-II,

[0014] Figure 3 Also shown on a larger scale are Figure 1 The support element in the cross section along the cutting line III-III and

[0015] Figures 4 to 6 Each is shown on a larger scale in Figure 1 The support segments in parallel cross sections along the cutting lines IV-IV, VV and VI-VI. DETAILED DESCRIPTION

[0016] The only partially shown support structure of the parabolic trough-shaped solar collector according to the invention comprises a support 1 with two abutment surfaces 2 for a support section, which preferably consists of a fiber-reinforced plastic shell 3, the two abutment surfaces 2 being arranged on opposite sides of the support, to which the support section is fixed side by side in the longitudinal direction of the support 1. The orientation of the support section relative to the support 1 is achieved by a stop angle 4 arranged on the plastic shell 3, which grips an orientation stop 5 on the support 1 in a form-fitting manner, the plastic shell 3 being kept oriented by the end wall 6 of the adjacent side of the plastic shell 3 resting on the relevant abutment surface 2. One leg of the stop angle 4 is advantageously formed here by an edge section of the end wall 6. In order to fix the stop position, the stop angle 4 can be provided with an edge strip along a foot protruding from the end wall 6, which is clamped relative to the support 1, for example, by means of a clamping screw, as Figure 2 and Figure 3 As shown in .

[0017] The plastic housing 3 forms a central rib 8 that projects from the housing base 7, starting from the adjacent end wall 6. This central rib 8 terminates at a distance before the opposite, outlet-side end wall 9. Side ribs 11 are provided between the central rib 8 and the side housing walls 10. In other words, according to this embodiment, two side ribs 11 are provided between the central rib 8 and the side housing walls 10. These side ribs 11 start from the outlet-side end wall 9 of the plastic housing 3, project from the housing base 7, and terminate at a distance before the adjacent end wall 6. The arrangement is such that one central rib 8 overlaps the other side rib 11.

[0018] The side shell walls 10 and the wall 12 of the central rib 8 protruding from the shell bottom 7 are provided with a stepped shoulder 13, which forms a stepped bottom section 14 with a continuously decreasing setback height towards the outlet-side end wall 9, as can be seen in particular from the Figure 2 and 3 Since the side ribs 11 start from this stepped bottom section 14 , a sufficient height of the side ribs 11 is also ensured in the region of the outlet-side end wall 9 in order to be able to ensure a corresponding resistance moment for the required dimensional stability of the plastic shell 3 .

[0019] This objective is achieved by converging the walls 12 of the central rib 8 and the walls 15 of the side ribs 11 starting from the relevant end face of the plastic shell 3, thereby increasing the transverse rigidity. The tapering of the central rib 8 and the side ribs 11 toward their ends also advantageously allows for a space-saving arrangement of the ribs. The side shell walls 10 can converge to achieve an effect similar to that of the walls 12 and 15 of the central rib 8 and side ribs 11. This provides for simple design requirements when the shell walls extend convergingly from the outlet-side end wall 9.

[0020] In order to be able to predetermine the plastic shells 3 arranged side by side on the support 1 for the Figure 2 and Figure 3 The parabolic trough of the reflector segment 16, which is only indicated by a dashed line, has a corresponding support surface in the plastic shell 3. The support surface is formed on the side shell wall 10 by the side edge flange 17 on the one hand, and is formed by the reflector support surface 18 of the central rib and the side rib 11 on the other hand and follows the direction of the parabolic trough, so that the reflector segment 16 pressed against the edge flange 17 and the reflector support surface 18 is kept extending along a parabola corresponding to the cross section of the parabolic trough.

[0021] If the mirror segment 16 is glued to the plastic housing 3 , end-face bonding should be omitted in the region of the adjoining sides in order to ensure pressure compensation between the environment and the housing cavity.

Claims

1. A solar collector with a support (1), comprising supporting sections arranged side by side, the supporting sections being fixed to adjacent surfaces (2) arranged on both sides of the support (1) and consisting of an open plastic shell (3), the supporting sections having side edge flanges (17) with predetermined parabolic grooves for accommodating reflector sections (16) and a central rib (8) protruding from the shell bottom (7) starting from the adjacent side end faces, the central rib (8) forming a reflector support surface (18) following the direction of the parabolic groove, characterized in that The central rib (8) ends before the outlet side end face opposite to the adjacent side end face, at least one side rib (11) protrudes from the shell bottom (7) between the central rib (8) and the side shell wall (10), the side rib (11) starts from the continuous end wall (9) of the outlet side end face and ends before the adjacent side end face and forms a reflector support surface (18) following the parabolic trough, the side shell wall (10) protruding from the shell bottom (7) and the wall (12) of the central rib (8) form a stepped shoulder (13).

2. The solar collector according to claim 1, characterized in that The central rib (8) starts from the adjacent side end face of the plastic shell (3), and the side ribs (11) taper from the end wall (9).

3. The solar collector according to claim 1 or 2, characterized in that The stepped shoulders (13) of the side shell walls (10) and the wall (12) of the central rib (8) form a stepped bottom section (14) having a setback height that continuously decreases toward the end wall (9), and the side ribs (11) protrude from the stepped bottom section (14).

4. The solar collector according to claim 1 or 2, characterized in that Two side ribs (11) are respectively provided between the central rib (8) and the side shell wall (10).

5. The solar collector according to claim 1 or 2, characterized in that The plastic shell (3) of the support section spans the stop angle (4) of the orientation stop (5) of the bracket (1) in a form-fitting manner on the adjacent side end face.

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