DE202007016715U1 - Scaffolding for solar collectors, especially for those with Fresnel lenses - Google Patents

Abstract

Scaffold (1) for solar collectors (2) comprising transverse bars (20) and longitudinal members (10) fastened thereon, characterized in that the longitudinal members (10) are self-supporting and in cross section isosceles triangles represent, wherein at the respective base surface of the side members (10) receptacles for one or a plurality of solar collectors (2) are provided and the longitudinal members (10) at their respective wedge tip (11) so connected to the crossbars (20) are that the wedge tips (11) of the side members (10) and the cross member (20) are arranged like a grid.

Description

The Invention relates to a scaffold for solar collectors, with a plurality of solar collectors to a flat unit can be summarized.

solar collectors are used for production and transport reasons in usually in small dimensions (up to about 1 × 2m) made. Because the solar collectors often they are not designed for mechanical loads, they need an additional Scaffolding, the appropriate stability for mechanical actions, e.g. from wind, lends.

Frequently Installed at a site several solar collectors whose Efficiency increases, when they are united as a unit. This is special for thermal solar collectors the case. It has proven to be beneficial proved that several solar collectors work together on a single, appropriately designed support structure to assemble.

Around To further increase the efficiency, solar collectors can tracked so that the sunlight is always as perpendicular to the solar panels incident. By a summary of several solar collectors to a unity the effort for the mechanics of the tracking significantly reduce, since several solar collectors only one common Need mechanics instead of individual.

From the JP-A-2001/53319 is a scaffold for a geographically extensive summary of solar collectors known. The scaffold consists essentially of a flat base frame, on the back of a bridge-like scaffold is arranged. This construction requires a Mittragen the solar collectors. Since the solar collectors are not suitable for absorbing mechanical loads, the solar collectors require a frame-like substructure. The provision of such substructures requires additional effort. Other embodiments are made US-7A-4845511 . US-A1-2005 / 035244 and US-A-5325844 known. As a reinforcement for areally arranged basic elements can therefore be provided in addition to bridge-like struts on the back and pyramid or prismatic braces. However, even in these constructions, the solar collectors are mechanically stressed.

Except adequate stability should such scaffolds easily be transportable and mountable, since their installation is often in Zones that are far away from the place of manufacture.

task The invention is the creation of a scaffold for solar collectors, the simple and lightweight elements with simple means composable is minimized, the mechanical load on the solar panels and nevertheless high stability especially opposite wind forces having. The solution consists in the features of claim 1 and preferably those the dependent claims.

The sees solution according to the invention a scaffold for solar collectors which comprises transverse beams and self-supporting longitudinal members fastened thereon, wherein the longitudinal members are isosceles in cross section Represent triangles, at the respective base surfaces of the longitudinal beams recordings for one or several solar collectors are provided and the side members on their Wedge tip are connected to the cross beams.

By the simple assembly of the scaffold according to the invention, in which only a single - in the Rule identical - side member to the Transverse bars must be attached, results in a continuous, preferably flat surface on which mounts a plurality of solar collectors immediately adjacent can be. The scaffold draws continue to be characterized by high stability.

The Own side members an isosceles triangular Cross-section. In an isosceles triangle, two of the three pages - the so called thighs - the same length up. The third page is the base of the triangle. The opposite of the base Corner is called a peak. In the case of an equilateral triangle, where all three sides have the same length, it is a special form of the isosceles triangle. Here can be free determine which side should represent the base. In the Episode then apply the rest Definitions for the isosceles triangle. A three-dimensional body whose Cross-section is an isosceles triangle, resembles a wedge. In the sense of this The invention therefore refers to the term wedge tip on the edge of the longitudinal member, the coincides in cross section with the apex of the isosceles triangle. The both other edges are called base edges. The area between the at the base edges is the base area, the areas between the wedge tip and each one of the base edges are the leg surfaces.

The solar collectors can be mounted on the base surface of the side members. It is preferred if a plurality of solar collectors can be mounted one behind the other in the longitudinal direction of the carrier. The width of the base surface of a longitudinal member preferably corresponds approximately to the width or the Length of the individual solar collectors, so that per rail a rail solar collectors is provided. The longitudinal members preferably all have the same length. At individual points along their wedge tips, the longitudinal members are connected to the transverse bars, wherein the distance between the attachment points of two adjacent longitudinal members corresponds to the width of their base surface and the transverse bars are arranged like a lattice with the wedge tips of the longitudinal members. Thus, the base surfaces of the carrier are flush next to each other.

The Longitudinal beams are self-supporting. That means they keep their shape, regardless of whether solar collectors are installed on them or not. The solar collectors So do not carry the structure with you. Because in the solar collectors no structural forces be initiated, the mechanical load on the solar panels in comparison to known scaffolds, at which the solar collectors support, minimized.

The Transverse spars are arbitrary to choose from their cross-section, wherein but rectangular or I-sections are preferred. They extend preferably perpendicular to the longitudinal beams and over the entire distance between the tips of the two longitudinal beams lying on the edge. Show the cross beams themselves preferably at a regular distance from each other.

The Longitudinal beams are preferably designed in half-timbered construction. Here are at the wedge tip as well provided at the base edges longitudinal beams, the interconnected by bracing. This can be done a high rigidity in longitudinal direction while achieving low weight, which in turn reduces the transport and facilitates the assembly.

Around the rigidity of the entire scaffold in Direction of the cross bars to increase, can be provided, the individual Side members on their connect adjacent base edges together. run along these base edges longitudinal struts, this means that the longitudinal spars two adjacent side members, the along the base edges run, be joined together. Preferably, this compound is soluble, e.g. by bolts, designed.

The Recordings for the solar collectors are preferably designed so that a through induced the scaffold, Mechanical stress on solar collectors is avoided as completely as possible. Here are particularly different thermal expansion coefficients to consider the individual components so that no tensions due to temperature changes occur. This can be done by to be chosen accordingly clearances be achieved, which can vary depending on the temperature. The entire scaffold should continue to be designed so rigid that a bending stress, the damage lead by solar collectors could, is avoided.

Also when the scaffold according to the invention itself in principle for every Any type of solar collectors are suitable, so are solar collectors particularly preferred with elongate Fresnel lenses. long Stretched Fresnel lenses focus the incident radiation on a focal line or a line from an infinite number of focal points. In the area these Burning line may be provided an absorption device, which the incident radiation in heat and / or converting electrical energy.

Is possible also the use of square, punctiform focusing Fresnel lenses. Around To obtain a single focal point, for example, two Frensel lenses, which the incident radiation each focus a focal line, rotated by 90 ° directly above each other arranged. In the resulting focal points of the individual lenses can then e.g. High-temperature solar cells are used, which are characterized by a particularly high efficiency. Whether the two Fresnel lenses with their smooth sides lie on each other or not, is irrelevant, moreover for the Focusing on a focal point.

The execution of the scaffold in Timber construction is particularly advantageous for this type of solar collectors, because with appropriate design, the beam paths from the lens to the focal line not or hardly affected become. It proves to be useful when the bracing the base area along the side member the boundary between two adjacent solar collectors run. By such struts can on the one hand secured the stability of the longitudinal member On the other hand, the solar collectors are supported and can additionally be secured along the respective edge.

It is particularly advantageous when the Fresnel lenses designed in such a way are that their focal line is located along the wedge tip of the respective longitudinal member. runs there can be a longitudinal spar this as the base area of the side member opened U-profile executed be. In this profile can then, for example, a conduit run through which a heat-carrying Fluid is pumped. The tube is expediently opposite the U-profile and the environment isolated, apart from the place on which the radiation hits.

The individual conduits of all longitudinal members are preferably connected to a line loop, ie the heat-carrying Flu id is at the one end of the loop is pumped into the lines and then passes through all the pipes before it exits at the other end of the line. Between input and output of the line loop results according to the invention, a temperature difference. The connection to the line loop can preferably be done by flexible hoses.

It but can also be provided that along the focal line of the Lens photovoltaic cells are arranged. Due to the high radiation intensity in this In this area, very high efficiencies can be achieved for power generation. Because of the radiation intensity arise at the photovoltaic cells very high temperatures. It can therefore continue to be provided in direct contact with or in small distance to the photovoltaic cells pipes on the side of the photovoltaic cells facing away from the Fresnel lenses relocate. these can on the one hand as cooling serve, let others the dissipated Heat on use.

Provided punctual Focusing Fresnel lenses are used, are the focal points the lenses preferably also along the wedge tip of the respective Longitudinal member. The high-temperature solar cells can then, as described above, over Conduits on the side facing away from the Fresnel lenses of the High temperature solar cells cooled become. According to their use, heat conductors optimized between high-temperature solar cells and the conduits are well known.

Conceivable is also that the individual high - temperature solar cells along the Side members on which they are, are displaceable. The shift can be manually or automatically, for each Cell individually or for several cells of a longitudinal member together respectively. In any case, the efficiency of the system can be further increased in which the high-temperature solar cells are always in focus a lens can be positioned: In a manual setting can so production inaccuracies of the Fresnel lenses considered be, with the automatic shift can be deviations compensate for the ideal beam path in real time.

at The use of photovoltaic or high-temperature solar cells can for Power line cable may be provided. But it is also possible the whole Framework, or at least the side member in the To use wedge tip as ground conductor. This makes it possible to get up to 50% of the needed Cable Total Length save. If the pipes for cooling the photovoltaic or High temperature solar cells sufficiently electrically from the carrier in the Wedge tip of the longitudinal member are insulated, These can be used as a second conductor. The cable requirement can be significantly reduced so on.

Around the efficiency of all solar collectors mounted on the scaffold can still be provided, the entire supporting framework of the sun can be provided to track. For this purpose, the scaffold is preferably so rotatable about one or two axes that it is in elevation and / or azimuth can be adjusted. In the most preferred Case of a biaxial adjustment are the movements separated in elevation and azimuth directions.

to Adjusting the azimuth angle, it is sufficient, the entire scaffold on one Place to store rotatable. Since the entire weight of the scaffold on the camp is resting for a corresponding adjustment requires little effort, which is why a servomotor attacking the bearing can be sufficient.

The Adjustment of the elevation angle usually requires a higher force. Independently of which play along this axis, the wind forces a greater role, so that the adjustment mechanism also the position of the supporting framework this got to.

Conveniently, should be provided to provide a circulating chain at one point connected to the scaffold is. The chain is so led that at an elevation angle of 0 ° - i. the scaffold is located in a horizontal position - the one, the connection point adjacent deflection point is above the connection point, and the other, the connection point adjacent deflection below of the connection point lies. By pulling the chain in the direction of Connecting point to the above deflection point, the scaffold is erected, i.e. the elevation angle increases. By pulling in the other direction, the scaffold is lowered, i. the elevation angle decreases. In addition, the dead weight of the scaffold to Magnification or Reduction of the elevation angle can be exploited. The chain piece, which leads from the connection point to the deflection point below, prevents that the scaffold due to of attacking wind forces set up unintentionally. Instead of a chain can also be a circulating toothed belt etc. use Find.

Around the for needed the adjustment Effort as low as possible to hold, the scaffold is preferably Made of lightweight aluminum.

The invention is not on a scaffold be restricts all installed solar collectors of the same type. Thus, it is possible, for example, both thermal solar panels with Fresnel lenses and photovoltaic cells without Fresnel lenses to operate simultaneously on a scaffold. It may be expedient to use for the respective solar collector type adapted longitudinal beams.

Around the wind forces in principle can reduce Wind gaps can be provided between the solar collectors. By It can flow at least a part of the moving masses of air, with which the wind pressure on the entire surface the solar collectors can be reduced.

The Invention will now be described with reference to the accompanying drawings based on an advantageous embodiment described by way of example. Show it:

1 an overall view of an embodiment of the scaffold according to the invention with mounted solar panels;

2 a cross section through a longitudinal spar;

3 a cross section through a strut;

4 a cross section through a longitudinal spar with inserted conduit;

5 a cross section through a longitudinal spar with inserted conduit and photovoltaic cell;

6 an overall view of an embodiment of the scaffold according to the invention with mounted solar panels;

7 a sheet-shaped Fresnel lens; and

8th a double-layered, point-focusing Fresnel lens.

In 1 is a scaffold 1 shown, which side member 10 and crossbars 20 includes. At the crossbars 20 these are standardized rectangular profiles. They run parallel and have a constant distance between them. The wedge is pointed 11 the side member 10 and the crossbars 20 are arranged like a lattice.

The side members 10 of the scaffold 1 have in cross-section the shape of an isosceles triangle and are designed in half-timbered construction. The longitudinal member is made up of longitudinal spars 16 . 17 in the wedge tip 11 and at the two base edges 12 . 13 , as well as from bracing 14 . 15 together.

The side members 10 are at their wedge tip 11 with the crossbars 20 connected while on their base area the solar collectors 2 are mounted. The distance between the individual mounting points of the side members 10 on the crossbars 20 is chosen so that there are two adjacent side members 10 at their opposite base edges 12 and 13 touch. To improve the stability, they are detachable there, for example by screws or bolts, connected together.

On each side member 10 finds a plurality of solar collectors 2 Space. The solar collectors 2 are in a row on the side member 10 assembled. This results between two adjacent solar collectors 2 abutting edges 3 , In the example shown, it is the solar collectors 2 stretched Fresnel lenses, which focus the sun's rays on a focal line. In order to suffer as little loss of radiation energy, the beam paths from lens to the focal line should be undisturbed, ie the largest possible proportion of solar collectors 2 should be used effectively. The struts 15 especially in the area of the base of the longitudinal member 10 do not cross the beam paths, which is why they are along the butt edges 3 the solar collectors 2 run. The solar collectors 2 lie on the struts 15 up and are supported by these. Because the braces 15 on the edge of the solar collectors 2 run, the bearing surface can be independent of the dimensions of the strut 15 to get voted. Because so only a small part of the beam paths through the solar panels 2 is disturbed, arises only a minor effect on the effective area of the solar collector 2 ,

The solar collectors 2 be both on the mentioned bracing 15 as well as on the longitudinal bars 17 along the base edges 12 . 13 attached. The struts 15 and the longitudinal struts 17 thus form a receptacle for the solar collectors 2 , In order to store the solar collectors without force - in particular, the thermal expansion of the individual components is taken into account because of differences in the temperature behavior of side members 10 and solar collectors 2 Tension can be induced - is an appropriate recording approach.

In 2 is an exemplary recording on a longitudinal spar 17 along a base edge 12 . 13 shown. The solar collector 2 is doing between the longitudinal spar 17 and a counterpart 30 trapped. The counterpart 30 is through a screw 31 detachable with the longitudinal spar 17 connected. Thus, the solar collector under temperature influence can stretch, is on its front side a space 32 whose dimensions may vary according to the temperature. So that the front side 4 of the solar collector 2 relative to the longitudinal spar 17 can move, are sliding jaws 33 intended. The counterpart 30 can extend over the entire length of the longitudinal spar 17 or only over the length of a solar collector 2 extend. But it is also conceivable, the solar panels 2 through a variety of small counterparts 30 to secure.

The solar collectors follow the same principle 2 also on the struts 15 Fasten. One possibility is in 3 shown. On the brace 15 are solar collectors on both sides 2 on. A through a screw 27 attached counterpart 34 completes the clamping of the collectors 2 , Again, there are free spaces on the front page 4 the solar collectors 2 provided, as well as sliding jaws 26 ,

In the example shown, a Fresnel lens as a solar collector 2 used, in which the incident radiation is focused in a focal line. The focal lines of the Fresnel lenses fall with the respective longitudinal beams 16 in the wedge tips 11 the side member 10 together.

As in 4 shown by way of example is such a longitudinal spar 16 in the wedge tip 11 designed as upwardly open U-profile. In this U-profile runs one of insulation material 42 surrounded pipe 40 , The insulation material 42 prevents unwanted heat exchange with the environment. Only the upper portion of the conduit is exposed, as at this point the through the Fresnel lenses 2 focused beams are incident and absorbed. The liquid passing through the conduit 40 flows, so is heated.

The pipes 40 all side members 10 are connected together to form a loop. This means that liquid enters the line loop at an entry point, all pipes 40 passes through before exiting the line loop at one endpoint. The supply and removal of the heat-carrying liquid to the input or from the end point are preferably realized by hoses. As a result, the mobility of the scaffold described below also becomes 1 not limited.

In 5 is a combination of electrical energy converters and heat in the wedge tips 11 the side member 10 shown. The bundled beams first hit a photovoltaic cell 41 where they are partially converted into electrical energy. The resulting heat is transferred to the heat conductor 43 to the underlying conduit 40 ge leads and dissipated by the liquid contained therein. On the one hand, this creates a cooling effect for the photovoltaic cell 41 On the other hand, the heat gained can continue to be used. Again, by insulation material 42 the heat loss to the environment is limited.

The scaffold 1 is how in 1 shown to two axes 50 . 51 rotatably mounted. This allows the scaffold 1 track the sun that their radiation is virtually perpendicular to the solar panels 2 impinges, whereby an increase in the efficiency of the entire system is made possible. When turning around the axis 50 the elevation angle is changed, with the scaffold 1 the illustrated position has an elevation angle of 0 °. By turning around the axis 51 the azimuth angle is changed.

So that a rotation around the axis 51 is possible, is the entire scaffold - as in 6 shown - rotatable on a pedestal 52 stored. Due to the high rigidity of the scaffold 1 and in the illustrated lightweight construction with truss structures, a single bearing point is sufficient. The base 52 has a swivel joint on its upper side 53 on which the weight of the scaffold perpendicular to the base 52 transfers. It's one on a sprocket 54 engaging servomotor 55 provided to accomplish the Azimutnachführung.

For the elevation tracking is the scaffold 1 along the axis 50 through the camps 57 rotatably mounted. For the angle adjustment are in the example shown two circumferential chains 56 . 56 ' intended. The number of parallel mounted chains 56 . 56 ' but is free to choose. The following explanations to the chain 56 also apply to any additional chain 56 ' , if available.

The chain 56 is at the connection point 58 firmly with the scaffold 1 connected. She is laying on a scaffold 59 attached pulleys 60 . 61 and 62 guided, wherein at least one of the deflection rollers can be driven. At the in 6 shown position of the scaffold 1 with an elevation angle of 0 ° that is along the chain 56 the connection point 58 adjacent pulley 60 above the connection point 58 appropriate. Will the chain 56 driven accordingly, the scaffold can 1 be raised, ie the elevation angle increases. When driven in the opposite direction, the scaffold lowers 1 especially because of its weight again.

Is the scaffold located? 1 in an upright position, so wind forces can attack on this. So that the elevation angle does not increase unintentionally, that is the connection point 58 adjacent pulley 62 Mounted below the scaffold, leaving the section of the chain 56 between connection point 58 and pulley 62 an unwanted installation of the scaffold 1 prevented.

In 7 is a sheet-like Frensel lens 80 shown. The exemplary drawn, incoming rays 82 be through the web-shaped lens 80 on a focal line 83 focused.

8th shows a double layered arrangement 81 two web-shaped Fresnel lenses 80 . 80 ' , The two Fresnel lenses are arranged rotated by 90 °. The exemplary drawn rays 82 on the arrangement 81 impact, are now in a focal point 84 focused.

Claims (11)

Scaffold ( 1 ) for solar collectors ( 2 ) comprising transverse spars ( 20 ) and longitudinal beams ( 10 ), characterized in that the longitudinal members ( 10 ) are self-supporting and represent in cross-section isosceles triangles, wherein at the respective base surface of the longitudinal members ( 10 ) Recordings for one or more solar collectors ( 2 ) are provided and the longitudinal members ( 10 ) at their respective wedge tip ( 11 ) so with the cross beams ( 20 ), that the wedge tips ( 11 ) the side members ( 10 ) and the cross beams ( 20 ) are arranged like a grid. Scaffold according to claim 1, characterized in that the longitudinal members ( 10 ) in truss construction from longitudinal beams ( 16 . 17 ) and braces ( 14 . 15 ) are executed. Scaffold according to claim 1 or 2, characterized in that the two adjacent longitudinal members ( 10 ) at their adjacent base edges ( 12 . 13 ) are interconnected. Scaffold according to claim 1, 2 or 3, characterized in that a tension-free receptacle for the solar collectors ( 2 ) is provided. Scaffold according to one of claims 1 to 4, characterized in that the solar collectors ( 2 ) are configured as web-shaped or double-layered, point-focusing Fresnel lenses. Scaffolding according to one of claims 1 to 5, characterized in that the struts ( 15 ) on the base surface of the longitudinal members ( 10 ) along the border ( 3 ) between two adjacent solar collectors ( 2 ). Scaffold according to claim 5 or 6, characterized in that the longitudinal spars ( 16 ) in the wedge tip ( 11 ) the side members ( 10 ) are configured as open to the base surface U-profiles. Scaffold according to claim 7, characterized in that line pipes ( 40 ) are provided, which in the U-profiles of the longitudinal beams ( 16 ) in the wedge tip ( 11 ) the side members ( 10 ), wherein the conduits ( 40 ) preferably form a line loop. Scaffold according to one of claims 5 to 8, characterized in that at the top of the longitudinal beams ( 16 ) in the wedge tip ( 11 ) the side members ( 10 ) Photovoltaic cells ( 41 ) are provided. Scaffold according to one of the preceding claims, characterized in that the scaffold ( 1 ) for adjusting the azimuth and / or elevation angle about one, preferably about two axes ( 50 . 51 ) is rotatably mounted. Scaffold according to claim 10, characterized in that for the adjustment of the elevation angle of the scaffold, a circulating traction means is provided which at one point ( 58 ) is connected to the scaffold and is guided so that at an elevation angle of 0 °, the connection point ( 58 ) adjacent deflection point ( 60 ) above the connection point ( 58 ), another, the connection point ( 58 ) adjacent deflection point ( 62 ) below the connection point ( 58 ) lies.