DE102007051383A1 - Solar power plant - Google Patents

Abstract

The invention relates to a system (1) for converting sunlight into another form of energy with a transducer device (2) which absorbs radiation incident thereon, a plurality of mirror elements (6a, 6b, 6c) spaced from the transducer device (2). are arranged to redirect sunlight irradiated on them in a working condition on the transducer means (2), wherein the individual mirror elements (6a, 6b, 6c) are each pivotable about at least one axis. The mirror elements (6a, 6b, 6c) are pivotable independently of one another and the system has a sensor device (10), which is arranged at a distance from the transducer device (2) and which emits a signal characteristic of a solar radiation incident on it. According to the invention, the mirror elements (6a, 6b, 6c) are individually aligned with the sensor device during operation, in order to be able to pivot it optimally onto the converter device (2).

Description

The The present invention relates to a plant for conversion from sunlight into another form of energy. The invention is under Reference to a solar power plant describes what sunlight converted into heat energy. It is noted, however, that the invention also in other types of solar power plants, for example in solar power plants with photovoltaic cells and the like application Can be found.

Out In the prior art, such solar power plants have long been known. More specifically, solar power plants are known which one Parabolic trough collector, which serves to raise the sunlight to focus on the parabolic trough. In addition are from the The prior art also collectors and in particular Fresnel collectors known to plan a variety of separate or just slightly have curved mirror strips around their longitudinal axis can be turned. It is possible, everyone This mirror strip always individually on an absorber tube focus. Depending on the position of the sun, the required Tilt angle of each of these mirror strips are determined exactly.

From the DE 27 42 014 C2 is a solar collector with solar followers known. In this case, a plurality of collectors is provided, which are arranged pivotably about its longitudinal axis. Axes with rods are arranged on these reflectors, so that the individual reflectors can be pivoted together and coupled to one another.

The EP 1 754 942 A1 describes a Fresnelsolarkollektoranordnung. Again, a plurality of primary mirrors is provided, wherein a movement of these individual mirrors is mechanically coupled and a common movement of these mirrors takes place by means of a push rod. In practice, however, the optimum angle, ie the angle at which the reflected angles radiate ideally to an absorber, can never be exactly reached, because measurement inaccuracies with respect to this angle at the mirror, wear, thermally induced deformations, displacements of the mirrors by wind pressure, Manufacturing and assembly inaccuracies, foundation lowering and much more hinders this. Even by a secondary mirror mounted in the prior art via an absorber tube, which deflects scattered light back to the absorber tube, the problem is solved only insufficiently.

From the DE19630201C1 is a solar power plant known in which many mirrors focus the sunlight on a central absorber. These heliostats are each equipped with their own sensor, which detects the light that falls off in the direction of the absorber.

Of the The present invention is therefore based on the object, an arrangement and to provide a method that allows despite the listed interference Align the mirror strips so that the light is focused exactly on one Absorber device falls. In addition, the energy input of the Be increased, in particular by a always optimal alignment of the mirror elements should be made.

This is inventively by a system according to claim 1 reached. Advantageous embodiments and developments are the subject of the dependent claims. An inventive Plant for converting sunlight into another form of energy has a conversion device which receives incoming radiation absorbed and a plurality of mirror elements, which spaced apart the transducer means are arranged to be in a working condition to redirect sunlight irradiated on them to the transducer device, wherein the individual mirror elements each about at least one axis are pivotable.

According to the invention the mirror elements at least partially independently pivotable and the system has a sensor device, which is a for a characteristic of the irradiated solar radiation Signal outputs. Furthermore, the sensor device is in a predetermined Spacing arranged with respect to this transducer device and responds to light coming from the mirror elements in the direction the sensor device is reflected. Here is the distance between the sensor device and the conversion device chosen at least as large that in the working state that of the mirror elements on the transducer device directed light does not reach the sensor device.

With the aid of this light- or heat-sensitive sensor device in the vicinity of the transducer device, a precise focusing of the mirrors and a subsequent alignment with the transducer device can be carried out. Preferably, the sensor device only reacts to such light that is reflected by the mirror elements in the direction of the sensor device. In addition, a detection of a degree of contamination of the mirror or the sensor device can be made via this sensor device. Under the working condition of the plant is understood a state in which a conversion of sunlight into another form of energy takes place. While in the prior art, the mirror elements are only movable together, can with the invention an adjustment of individual mirror elements take place while other mirror elements are already aligned. More specifically, individual correction of individual mirrors may take place. The plurality of mirror elements concentrates the light on the transducer device.

Would the sensor device is arranged directly in the region of the converter device, so would synonymous with individually driven mirror elements each mirror element for itself in the direction of the transducer device be aligned with the remaining mirror from the transducer device have to be turned away to enable this single adjustment. In this case, so the plant could during the referencing procedure (i.e., the adjustment procedure for the mirrors) give no performance, which is why a readjustment is rare can be made. By spacing the sensor device from the transducer means, however, a Einzeljustage the mirror elements be made while at the same time the other mirror elements reflect the light towards the transducer device. Prefers is the sensor device laterally next to the transducer device arranged.

at the converter device is in particular but not exclusive around an absorber tube, which reflects the sunlight emitted on it in heat energy, for example for flowing therein Water, converts. However, it would also be converter devices conceivable, which convert light directly into electrical energy.

Preferably a precise angle is determined for each mirror element, around which the mirror element has to be pivoted to the reflected light to redirect from the transducer device to the sensor device.

Preferably The system has a variety of motor drive devices on which the pivoting movements of the individual mirror elements cause. It would also be possible, not every to control individual mirror element separately, but individual groups to form mirror elements whose movement is coupled together are. These may in particular be groups of several adjacent ones Play elements or mirror rows, which then over a separate control motor individually and in their own Optimized alignment to the converter device or the absorber tube become.

at a further advantageous embodiment, the Plant on a control device that causes individual Mirror elements are controlled such that the deflected by them Radiation is directed to the sensor device while the deflected by the other mirror elements radiation gets to the transducer device. For this purpose, a sensor device is used, which are arranged in a defined position next to the transducer device is. This sensor device thus serves for referencing a each mirror element or each group of mirror elements and becomes cyclically separate from all mirror elements during operation approached.

through the measuring signal of the sensor device and the angle measured thereto of the mirror element is the position of the transducer means indirectly known. The mirror element only has to be at the given angle to be rotated to the transducer device. This angle between the sensor device and the converter device is small, for example in the range of 2 ° -5 °, preferably in the range of 3 °, so that the angle measuring device on the mirror element does not require high absolute accuracy.

Preferably However, the measuring system itself has a very fine resolution on, so that a return movement of the said angle d. H. for example, follows as error free as possible by 3 °. As mentioned above, the sensor device is advantageous positioned so far as to be adjacent to the transducer device is that they are not a disturbing light in particular neither Disturbing light on the absorber tube (ie the transducer device) aligned remaining mirror elements. The control device preferably controls cyclically the individual mirror elements, this being done on the fly, as mentioned above can.

at Another preferred embodiment is at least a mirror element to two preferably perpendicular to each other Swiveling axes. Particularly preferred are several and especially prefers all mirror elements pivotable about two axes. These Embodiment is particularly suitable for so-called. Tower power plants, in which the mirror elements in the circumferential direction to the converter device are distributed. In such embodiments the converter device preferably has a point or spherical shape Build up. Preferably, the sensor device is not laterally arranged next to the transducer means, but over or below this and preferably above the sensor device.

More accurate are said in the case of such a solar tower power plant the Single mirror on the above or below the central transducer device arranged sensor is referenced, each mirror is a two-dimensional Search movement in a predefined window around the sensor.

at a further advantageous embodiment, the Plant a variety of sensor devices. Especially preferred For example, a plurality of such sensor devices can be of length the transducer device, which is preferably an absorber tube distributed be, for example, at each end of this absorber tube, a sensor device. In this way, for example, a possible torsion of z. B. 100 m long mirror element (which, for example, by wind load, which is dependent on the individual mirror angle, caused is determined) between the ends of the mirror element and the mirror angle be corrected so that the striking on the entire absorber tube Maximum light output is.

To For this purpose, for example, the measured values of the two Sensor devices are evaluated and the mirror element an angular position to be aligned, which is a favorable average or a favorable total irradiation of the power the sensor device causes. In a further advantageous Embodiment are at least three sensor devices provided, which is particularly useful if the servomotors the mirror elements in the middle of the mirror attack, so that in this case, the three sensor devices at the beginning, in the middle and are arranged at the end of the transducer device.

As mentioned above can be plane as mirror elements Mirrors, but it would also be possible parabolic curved mirrors provide. Further points in a particularly preferred embodiment at least a mirror element and preferably several and more preferred all mirror elements on two planar sections on which a predetermined angle against each other are angled. Through this given angle between these two sections, in common forming the mirror element can also provide improved focus can be achieved on the transducer device. On the other hand that is Provide these two planar sections that are against each other Angled, less expensive than a single curved Mirror. These two subsections are preferred with respect to a longitudinal direction of the mirror element angled against each other.

There all mirror elements must be tracked so the sun that they reflect the light directly onto the transducer device, can the described referencing each individual mirror element or any group of mirror elements for the rest Mirror elements or mirror groups deliver the setpoints. The system can then be self-sufficient track of the sun, taking on an external angle specification can be dispensed with.

The The present invention is further directed to a method of operation from a plant to the conversion of sunlight into another form of energy directed, having a plurality of mirror elements on this incoming sunlight directed to a transducer device and this converter means the sunlight at least partially converted into another form of energy and wherein the individual mirror elements are each arranged pivotably. According to the invention Mirror elements at least partially independent of each other swiveling and during a working operation is a variety aligned by mirror elements such that the sunlight is on the conversion facility is aligned, and become individual mirrors pivoted so that the sunlight they diverted up a spaced from the transducer means arranged sensor means meets.

In order to is also in the inventive method a Einjustierung or referencing individual mirror elements preferably ensured in working mode. Also radiate the remaining mirror elements from the light on the conversion device and only individual or individual groups of mirror elements readjusted.

Preferably are each individual mirror elements or groups in sequence pivoted out of individual mirror elements that of them deflected sunlight at the spaced apart from the converter arranged sensor device hits. The remaining mirror elements stay during this procedure (on the converter device) aligned.

Preferably For example, the single mirror element is triggered in response to an output from the sensor device Signal aligned again. More precisely, first this single mirror element aligned such that the sensor device a outputs maximum signal or a plurality of sensor devices spend a maximum average. This measurement signal is an indication for that now the mirror element in question ideal is aligned with the sensor device. Subsequently, will the mirror element is adjusted via a known angular offset, so that it is then exactly on the transducer device is aligned. In this case, each mirror element an individual Be associated with angular offset. These angular offsets are by geometry the arrangement predetermined.

Preferably, individual mirror elements are re-aligned in response to signals output from a plurality of sensor devices. In this approach, several effective reference positions from the individual Referenzposi determined for these sensor devices calculated and calculated on the basis of these average values mentioned above, an optimum position of the relevant mirror element.

at a further advantageous method detects at least one sensor device a variety of characteristic signals depending on these associated pivot positions of the single mirror element and the course of these characteristic signals becomes a reference angle determined the individual mirror element. Preferably it is These signals are signals that are suitable for an intensity of the incident on the sensor device Light are characteristic. In this process are different such intensity values as a function of evaluated their associated angle values. Subsequently is preferably the maximum of the intensity values, possibly also by interpolation, determined and assigned to this maximum Reference angle. Taking into account this reference angle the mirror element in question is then placed on the Aligned converter device.

at the further advantageous method is from the characteristic Signals on surface impairments of a closed individual mirror element. With these surface impairments For example, it can be punctual or areal Dirt, to break glass or the like act. It is advantageous, by a suitable control a distinction to meet, on the one hand between sun damage, like a cloudy sky, and on the other hand surface impairments of the mirror element is different.

This can be done, for example, that the signals of several Sensor devices are taken into account. If only some sensor devices provide an attenuated signal, This may be an indication that although sunlight is present is, but a pollution on the surface of the concerned Mirror element is present. To distinguish whether the surface the mirror element is damaged or the sensor device itself is defective, in turn, the angle can be varied. If If the measurement signal does not change, this indicates a defective sensor device, if the measurement signal at least changes slightly, this indicates pollution of the mirror element. In another preferred method is converted from these characteristic signals to operational errors of Plant closed. More precisely, the referencing described here also be used to detect errors in the plant and to locate.

Preferably be signals of the sensor device in dependence of a tilt angle of the mirror elements during a and return movement of the mirror elements when sweeping the sensor device detects and accuracy by evaluating both directions is improved.

Further Advantages and embodiments will be apparent from the attached Drawings.

In this demonstrate:

1 a schematic representation of a system according to the invention; and

2 a mirror element.

1 shows a plant according to the invention 1 to convert sunlight into another form of energy. This plant 1 has a transducer device 2 spaced apart from a plurality of mirror elements 6a . 6b . 6c is arranged. In this case, this converter device via a carrier 4 spaced from the individual mirror elements 6a . 6b . 6c held.

The mirror elements 6a . 6b . 6c serve to irradiate sunlight (see arrow P1) in the direction of the transducer device 2 to reflect (arrow P2). In the converter device 2 this is an absorber tube which extends in a direction perpendicular to the plane of the figure. Also the individual mirror elements 6a . 6b . 6c extend perpendicular to the plane of the figure and may have, for example, lengths in the range of 100 m and widths in the range of 10 to 30 cm.

The individual mirror elements 6a . 6b . 6c are on a support plate 8th on both sides with respect to the transducer device 2 arranged. The carrier 4 is about a fixed bearing on this support plate 8th firmly arranged.

How out 1 can be seen, the pivotal position of the individual mirror elements 6a . 6b . 6c depending on the position of the pivoting mirror relative to the transducer device 2 varies and depends on the angle at which the sunlight is irradiated. The individual mirror elements 6a . 6b . 6c are with respect to swivel axes 11 pivotable in the plane of the figure by a predetermined angle. The reference number 12 refers to a drive device for the mirror elements 6a . 6b . 6c ,

The reference number 10 refers to a sensor device that is spaced from the transducer device 2 is arranged. This is preferably a light sensor. On the basis of the referencing to this sensor device 10 As measured light intensity and distribution conclusions can be drawn on the correct orientation of the mirror elements as well as on a state this mirror element such as pollution, which can be done in particular in comparison to the other mirror elements. The reference numeral d refers to the lateral distance between the transducer means 2 and the sensor device which, as stated above, is preferably a light sensor.

If, for example, a measured light intensity varies greatly with the same solar radiation, then some of the mirror elements are 6a . 6b . 6c or mirror groups dirty. This makes it possible, without additional control of the mirror elements 6a . 6b . 6c directly derive the degree of contamination and make it a statement about a cleaning to be carried out. From a reduced intensity in all mirror elements 6a . 6b . 6c For example, contamination of the sensor device 10 getting closed.

Furthermore, with a combination of the sensor device with the described tracking system damage, defects and the like can be reliably recognized on the individual system components, such as the drive or the installation, by the signals of the individual mirror elements 6a . 6b . 6c and the mirror groups are compared. Is at one or more mirror elements 6a . 6b . 6c or groups no referencing possible, an error and the exact location in the entire system can be derived. In this way, a very quick elimination of the error is possible.

The positioning of the individual mirror elements 6a . 6b . 6c done with servomotors. During normal operation, one mirror element after the other cyclically changes from the converter device 2 on the defined adjacent sensor device 10 referenced (arrow P3). From there it moves precisely back to the transducer device by the predetermined angle 2 ,

At the in 1 shown embodiment, as mentioned above, also several sensor devices 10 over the length of the transducer device 2 be distributed so as to recognize in this way, as mentioned above, a torsion of the mirror elements and to average out. This is always an optimal focus of the mirror elements 6a . 6b . 6c guaranteed without interrupting the operation. By setting up and tracking each mirror element 6a . 6b . 6c or each mirror group in the operation of the system can be achieved that the remaining mirror or mirror groups remain aligned with the transducer device. In this way, only little power is lost.

If several sensor devices 10 are provided, these sensor devices preferably each have the same distance from the (preferably as a straight tube) executed transducer device ( 2 ) on. In addition, an elongate sensor device could also be used 10 be used, whose longitudinal direction is parallel to the transducer device 2 extends.

going For example, from a time requirement of about 10 seconds for a referencing, which then, for example, every 60 seconds takes place, it goes with an assumed number of 48 mirror elements only a 1/48 × 10/60 = 0.35% of the power lost. This however, is carried out by the highly precise Alignment of all mirrors balanced in each case.

The reference number 15 refers to a control device. This control device 15 processes the from the sensor device 10 output measured values or signals and controls on this basis, the drive means 12 for the individual mirror elements 6a . 6b . 6c , The reference number 16 denotes a memory device in which characteristic values, such as the offset angle for the individual mirror elements 6a . 6b . 6c are stored.

2 shows an example of a mirror element in a preferred embodiment. This mirror element has two planar sections 18 . 19 on, which are angled at a predetermined angle to each other. This bend improves the focus on the transducer device 2 reached.

All Features disclosed in the application documents are considered to be essential to the invention as far as they are individually or in combination the prior art are new.

1

investment

2

transducer means

4

carrier

6a, 6b, 6c

mirror elements

8th

support plate

10

sensor device

11

swivel axis

12

driving means

15

control device

16

memory device

18 19

sections of the mirror element

P1, P2, P3

arrow

d

Distance between transducer device 2 and sensor device 10

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 2742014 C2 [0003]
• EP 1754942 A1 [0004]
• - DE 19630201 C1 [0005]

Claims (15)

Investment ( 1 ) for converting sunlight into another form of energy with a converter device ( 2 ), which absorbs radiation incident thereon, a plurality of mirror elements ( 6a . 6b . 6c ), which are spaced apart from the transducer device ( 2 ) are arranged to transmit sunlight irradiated thereon in a working condition to the transducer means ( 2 ), wherein the individual mirror elements ( 6a . 6b . 6c ) are each pivotable about at least one axis, characterized in that the mirror elements ( 6a . 6b . 6c ) are at least partially independently pivotable and the system at least one sensor device ( 10 ) which outputs a signal characteristic of a solar radiation irradiated thereon and outputs the sensor device ( 10 ) at a predetermined distance (d) with respect to the transducer means ( 2 ) and reacts to light which is reflected by mirror elements in the direction of the sensor device and that the distance (d) between the sensor device ( 10 ) and the converter device ( 2 ) is at least chosen so large that in the working state of the mirror elements on the transducer device ( 2 ) directed light not on the sensor device ( 10 ). Investment ( 1 ) according to at least one of the preceding claims, characterized in that the plant ( 1 ) has a plurality of motor drive means, which the pivoting movements of the mirror elements ( 6a . 6b . 6c ) cause. Investment ( 1 ) according to claim 1, characterized in that the system comprises a control device ( 20 ), which causes individual mirror elements to be controlled in such a way that the radiation deflected by them is transmitted to the sensor device ( 10 ), while those of the other mirror elements ( 6a . 6b . 6c ) deflected radiation to the transducer device ( 2 ). Investment ( 1 ) according to at least one of the preceding claims, characterized in that at least one mirror element ( 6a . 6b . 6c ) is pivotable about two axes. Investment ( 1 ) according to at least one of the preceding claims, characterized in that the system comprises a plurality of sensor devices ( 10 ) having. Investment ( 1 ) according to at least one of the preceding claims, characterized in that the converter device ( 2 ) as a pipe ( 2 ) and a plurality of sensor devices ( 10 ) along this tube ( 2 ) are arranged. Investment ( 1 ) according to at least one of the preceding claims, characterized in that at least one mirror element ( 6a . 6b . 6c ) two planar sections ( 18 . 19 ), which are angled at a predetermined angle to each other. Method for operating a plant for converting sunlight into another form of energy, wherein a plurality of mirror elements ( 6a . 6b . 6c ) on this incoming sunlight to a transducer device ( 2 ) and this converter device ( 2 ) at least partially converts the sunlight into another form of energy, wherein the individual mirror elements ( 6a . 6b . 6c ) are each arranged pivotably, characterized in that the mirror elements ( 6a . 6b . 6c ) are at least partially independently pivotable and a plurality of mirror elements ( 6a . 6b . 6c ) is aligned so that the sunlight on the transducer device ( 2 ) and individual mirror elements ( 6a . 6b . 6c ) are temporarily pivoted such that the sunlight deflected by you at a distance from the transducer device ( 2 ) arranged sensor device ( 10 ) meets. A method according to claim 8, characterized in that in each case individual mirror elements ( 6a . 6b . 6c ) or groups of individual mirror elements ( 6a . 6b . 6c ) are pivoted so that the sunlight deflected by you on the spaced from the transducer device ( 2 ) arranged sensor device ( 10 ) meets. Method according to at least one of the preceding claims 8-9, characterized in that the individual mirror elements ( 6a . 6b . 6c ) in response to a signal from the sensor device ( 10 ) is aligned again. Method according to at least one of the preceding claims 8-10, characterized in that the individual mirror element ( 6a . 6b . 6c ) is readjusted in response to signals output from a plurality of sensor devices. Method according to at least one of the preceding claims 8-11, characterized in that at least one sensor device ( 10 ) a plurality of characteristic signals in dependence on these associated pivot positions of the single mirror element ( 6a . 6b . 6c ) and from a course of these characteristic signals a reference angle of the individual mirror element ( 6a . 6b . 6c ) is determined. Method according to at least one of the preceding 8-12, characterized in that Signals of the sensor device ( 10 ) in dependence on a pivot angle of the mirror elements ( 6a . 6b . 6c ) during a back and forth movement of the mirror elements ( 6a . 6b . 6c ) when sweeping the sensor device ( 10 ). Method according to at least one of the preceding claims 8-13, characterized in that from the characteristic signals to surface impairments of the individual mirror element ( 6a . 6b . 6c ) is closed. Method according to at least one of the preceding Claims 8-14, characterized in that off closed the characteristic signals on operational error of the plant becomes.