WO2012062902A2

WO2012062902A2 - Heliostat having an associated receiving element

Info

Publication number: WO2012062902A2
Application number: PCT/EP2011/069929
Authority: WO
Inventors: János PALI
Original assignee: Ppp Sonnenkraft Gmbh
Priority date: 2010-11-11
Filing date: 2011-11-11
Publication date: 2012-05-18
Also published as: WO2012062902A3; DE102010043790A1

Abstract

The present invention relates to a heliostat 1 having a mirror unit 60 for reflecting and focussing sun rays S onto a target 3, wherein the mirror unit 60 is mounted such that it can rotate about a first main axis A-A' which is always oriented in the direction of the target 3; and wherein the mirror unit 60 is mounted such that it can rotate about a second main axis B-B' which is arranged perpendicular to the first main axis A-A' and perpendicular to the surface normal N of the mirror unit 60 and rotates together with the mirror unit 60 about the first main axis A-A', wherein the rotary movement of the mirror unit 60 about the second main axis B-B' is effected by means of a first mechanical gear mechanism 120 as a result of the rotary movement of the mirror unit 60 about the first main axis A-A'. The invention also relates to a receiving element 3 which is suitable for the heliostat 1, and to a system for converting solar energy into thermal energy.

Description

Heliostat with associated receiving element

1. Field of the invention

The invention relates to a heliostat and an associated receiving element for the use of solar energy, in particular for the support of industrial or private heating systems. Heliostats are usually used to reflect the sun's rays to a specific destination, where they can use the light for lighting purposes or convert solar energy into heat with zero emissions.

2. State of the art

The development of heliostats dates back to the 18th century. The idea is to steer the sun's rays, which are different over the course of the day, via a heliostat to a fixed target in order to use sunlight for lighting purposes or solar energy for heating purposes. In recent years, heliostat technology has been used in particular in solar power plants in Spain or the USA, where the incident sunbeams are concentrated on a solar tower via a large number of heliostats. The heliostats direct the sun's rays onto a fixed absorber, which first converts the solar energy into heat energy, which can then be converted into electricity via turbines. In addition, the heat energy is also used directly for emission-free melting of materials. An efficient and at the same time variable system with respect to the receiver to convert solar energy into thermal energy represents a problem that has not yet been optimally solved. Thus heliostats with concentration levels characterized by a high energy yield exist, but once mounted do not have different arrangements Receiver can illuminate or only with a lower focus, ie a low energy yield.

Such a sun-ray-concentrating solar optics system with heliostats is known from EP 045 921 Ai. The solar optics system described therein has a stationary established receiver, in which one of a heliostat with Concave mirror concentrated light beam regardless of the position of the sun from a constant direction, mainly incident in the direction of the symmetry axis of the receiver. The focal point of the concave mirror of the heliostat must lie on the so-called "sidereal axis", which runs parallel to the Earth's axis For daily operation, the concave mirror must continue to rotate around this sidereal axis and only needs to compensate for seasonal fluctuations in the summer and winter turns A disadvantage of this solar optics system is that the arrangement of the heliostat and the position of the receiver are determined by the kinematics.The sun's rays can not be directed in any direction Furthermore, heliostats are known that can focus on any target, but this requires a variety of drives and thus energy to optimally positioning the helicopter ostaten.

One such sun-ray concentrating heliostat is known from GB 2 329 976 A. Here, the concentration mirror of the heliostat comprises a grid of individually controllable rotatably mounted mirrors which focus the sun's rays on a desired target. For focusing, the individual rotation axes of the individual mirrors are driven individually, electrically or hydraulically. Thus, the concentration level changes its focus during the day. The concentration level as a whole is rotated during the course of an hour about an axis which is directed to the target and pivoted about a co-rotating axis perpendicular thereto. This ensures that the incident solar rays, which reflect the target sun's rays, the surface normal of the concentration level and a central axis through the concentration levels in a plane. This reduces the degree of freedom for adjusting the individually rotatably mounted mirror on only one axis of rotation per single mirror. A disadvantage of this heliostat, however, that for the two main axes and for each of the axes of rotation of the individual mirrors each drive motor velvet Control must be provided. This results in a variety of drives and controls and the heliostat is technically complex and expensive.

The present invention therefore has as its object to provide a heliostat and an associated receiving element for efficient energy conversion of solar energy into heat of a temperature range of 50 - 2000 ° C. The influence of the external temperatures on the efficiency should be as low as possible. In addition, the positioning of the heliostat should be independent of the direction of the compass and thus an arbitrarily arranged receiving element can be focused. In addition, the most robust and cost-effective tracking of the heliostat should be provided.

Furthermore come in conventional solar power plants bundled sun rays from different directions to the receiving elements. Although the receiving elements of such power plants have a high absorption efficiency due to the high surface temperature, they show significant reflection heat losses and convective heat losses due to their necessary open design. The typical thermal efficiency of these receivers is therefore only 60-65%. It is therefore an object of the present invention to provide a receiving element and a system of heliostats and receiving element, which has a higher thermal efficiency.

3. Summary of the invention

The above object is achieved by a heliostat according to claim 1, a receiving element according to claim 13 and a system for the conversion of solar energy into heat energy according to claim 15.

In particular, the above-mentioned object is achieved by a heliostat, comprising a mirror unit, for reflecting and focusing sun rays on a target, wherein the mirror unit is rotatably mounted about a first main axis A-A ', which is always aligned in the direction of the target and wherein the mirror unit is rotatably mounted about a second main axis BB 'which is perpendicular to the first main axis AA' and perpendicular to the surface normal N of Mirror unit is arranged and rotates with the mirror unit about the first major axis AA ', wherein the rotational movement of the mirror unit about the second main axis BB' by means of a first mechanical transmission by the rotational movement of the mirror unit about the first main axis AA 'is effected.

The fact that the heliostat has two main axes A-A 'and B-B' for the movement of the mirror unit, wherein the first main axis A-A 'is aligned in the direction of the focal point, the heliostat of the sun orbit can be directed according to any target, at the distance of the focal point. This is not possible with heliostats that have their focus on the sidereal axis. The direct mechanical coupling of the two main axes A-A 'and B-B' through a first mechanical transmission reduces the number of drives required to position the heliostat on a single drive, which preferably drives the first major axis A-A '. Other drives and complex and expensive controls for the second main axis B-B 'are not necessary by the mechanical transmission. The heliostat according to the invention is very robust and inexpensive and can therefore be used in many ways for the efficient use of solar energy. In particular, the heliostat according to the invention can also be used for heating purposes in private or commercial buildings.

In a preferred embodiment, the first main axis AA 'is arranged so that upon rotation of the mirror unit about the first main axis A- A' sun rays, the unit on a line of symmetry of the mirror, which is perpendicular to the second major axis BB ', incident, and from there are always located in an area which is spanned by the symmetry line and by the surface normal of the mirror unit.

Because the first main axis AA 'is always aligned with the focal point of the mirror unit and the incident and reflected beams are always in the plane defined by the symmetry line and the surface normal of the mirror unit, a mirror unit whose focus is only used to concentrate the sun's rays with respect to an axis is variable, to optimally focusing reflection of the sun's rays guarantee. In some cases, due to this control of the mirror unit, the focusing error is even negligible.

The first mechanical transmission preferably has a control surface fixed relative to the first main axis A-A ', which taps off a pickup articulated on the mirror unit in order to mechanically effect rotation of the mirror unit about the second main axis B-B'. Characterized in that the movement sequence of the second main axis B-B 'is determined by the control surface and is clearly coupled to the movement of the axis A-A, the movement of the second main axis B-B' does not have to be individually driven and controlled. This minimizes the control engineering effort, reduces the number of motors to be used, the necessary controls and the costs incurred. Preferably, the control surface is adjustable in orientation to be aligned parallel to the plane of the sun orbit. Due to this orientation, the mirror unit can be adapted to the solar path according to the location of use. In this case, the cam track predetermines the assignment of the movement of the second main axis B-B 'to the first main axis A-A, depending on the location.

The control surface is preferably parallel displaceable in order to adapt its position to the seasonal height of the plane of the sun track. Due to this parallel displacement, the angular orientation of the control surface can be maintained throughout the year and the control surface only has to be adjusted from time to time to the sun altitude of the respective day.

Preferably, the mirror unit of the heliostat on mirror rows, each consisting of several plan individual mirrors or a curved mirror strip, the mirror rows are individually mounted about a mirror row axis CC, which is arranged parallel to the second main axis BB 'rotatably mounted on the mirror unit. Due to the fact that the mirror rows are rotatably mounted about the mirror row axis CC, a focusing error of the mirror unit due to the tracking can be compensated during the course of the day and thus the maximum of solar rays can always be reflected onto the target. Because the first main axis AA 'is always aligned with the focal point of the mirror unit and the incident and reflected beams always lie in the area spanned by the symmetry line and the surface normal of the mirror unit, the individual mirrors or the mirror strips forming the concentrating mirror unit can and their individual orientation on the mirror unit may be variable during the course of the day, in order to set a fixed axis parallel to the symmetry line of the mirror unit. To compensate for Fokussierangsfehlers only one rotation of the individual mirror or mirror strip to the mirror row axis CC is necessary. Accordingly, only one drive or one control is needed to control the pivoting angle of the individual mirrors and mirror strips, so that control input and drive effort can also be saved here, and optimum focusing is nevertheless achieved in every position of the mirror unit.

Preferably, the heliostat comprises a second mechanical gear, wherein the rotational movement of the rows of mirrors about the mirror row axis CC by means of a second mechanical transmission by the rotational movement of the mirror unit about the second major axis BB 'is defined. By implementing the movement of the second main axis BB 'in the individual rotational movements of the rows of mirrors about their mirror row axes CC, the two movements are mechanically coupled to each other and a separate control for the movement of each row of mirrors deleted. Preferably, the second mechanical transmission on individual cam tracks for driving the individual rows of mirrors, which are fixed with respect to the second main axis BB 'and which rotate with the mirror unit about the first main axis AA'. The curved tracks allow the individual rows of mirrors to be mechanically controlled independently of each other in order to ensure optimum focus on the desired destination during the day. By this arrangement, no individual drives per mirror row axis CC are required, so that this setting of the mirror rows is cost-effective, robust and yet very accurate. Preferably, the heliostat on a tracking, which takes place during the day exclusively by a drive of the rotation of the mirror unit about the first major axis AA '. Due to the mechanical coupling, in particular of the main axes AA 'and BB' but also C-, the tracking of the heliostat can take place via a single drive motor, which acts on the first main axis AA ', which is spatially fixed in the operating state.

In a preferred embodiment, a backbone of the heliostat is rotatably and / or pivotally mounted to illuminate differently located targets with a single heliostat, while maintaining alignment of the control surface of the first mechanical gear to the sun track for all different targets. Thus, the heliostat can irradiate from any location from multiple targets located at a distance from the focal point. By the arbitrary choice of the target irradiated by the heliostat, the conversion of the solar energy into heat energy can be done directly at the place of the consumer and thus no energy loss due to an energy transport is incurred. The heat is generated directly where it is needed, for example in a building or in a specific apartment in a building. This makes it possible to use only one common heliostat for solar energy production for several buildings or several apartments in a building.

Preferably, the heliostat further comprises a power control mechanism in which rows of mirrors are individually pivotable about their mirror row axis C-C in order to no longer focus the sun's rays on the original target. Through this power control mechanism, it is possible to quickly control the solar radiation reflected by the heliostat without having to change the orientation of the heliostat to the target. Accordingly, the power can be regulated without significant delay and there is no need to reposition the entire heliostat.

In particular, the above-mentioned object is achieved by a receiving element for receiving and absorbing focused sunbeams, comprising an absorber, a radiation channel and annular reflection surfaces which are arranged on the wall of the radiation channel so as to be separated from the absorber Reflect reflected radiation back to the absorber out. By arranged on the wall of the Einstrahlkanals reflecting surfaces of the proportion of preferably converted into heat solar energy is optimized and thus the efficiency of the overall system.

The receiving element preferably has a deflecting mirror in the irradiation channel, which guides the sun's rays toward the absorber in a solar chimney which is angled upward toward the injection channel. An angled Einstrahlkanal with a deflecting mirror and a solar fireplace extending upward reduces the heat loss of the absorber, since in the upwardly extending part of the Einstrahlkanals almost no convection takes place. Furthermore, it is possible by this arrangement to set up different absorbers on the Einstrahlkanal, such as liquid heat exchangers,

Heat storage elements, ovens, tiled stoves, furnaces, etc.

In particular, the above-mentioned object is also achieved by a system for converting solar energy into thermal energy having at least one heliostat described above and at least one receiving element described above. Due to the fact that the focused sunrays can always be incident on the heliostat from the same direction, the receiving element can be optimized for this direction of incidence. This makes it possible to provide receiving elements whose absorber is located deep within the receiving element, whereby heat losses are greatly minimized. In particular, the radiation reflected back from the absorber can be minimized. The system of heliostat and adapted receiving element therefore has a much higher efficiency than conventional heliostat systems in which several heliostats have a common goal. 4. Brief description of the drawings

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In which shows: a section in side view of a third embodiment of a heliostat according to the invention when focusing sun rays on an embodiment of a receiving element according to the invention; 2 shows a three-dimensional overall view of a first embodiment of a heliostat according to the invention, with axes DD 'fixed relative to the mirror unit and tracking axes CC for positioning individual mirrors of a mirror unit; Fig. 3: a three-dimensional representation of the sun paths in Central Europe at the summer solstice, winter solstice and equinoxes relative to the inclination of the earth's axis;

Fig. 4: a side view of the heliostat of FIG. 2, with representation of

Tilt angle of a control surface of a first mechanical

Gearbox in relation to the sun track; a three-dimensional overall view of the heliostat of Figure 2 from the back of the mirror unit. a side view of the first mechanical transmission for transmitting the movements of a first main axis A-A 'to a second main axis B-B' of the heliostat of Fig. 2; 7 and 8: three-dimensional detail views of the first mechanical

Transmission of Fig. 6;

9 shows a three-dimensional representation of a control arm, oriented on the basis of the sun track;

10 shows three-dimensional representations of the control surface and of a corresponding pickup of the first mechanical transmission; 11 shows a three-dimensional representation of the heliostat with a second mechanical transmission for controlling individual rows of mirrors;

12A-B: a three-dimensional representation and a side view of a

Curved track of the second mechanical transmission of Fig. 11;

13 shows a three-dimensional representation of the second mechanical transmission and the rows of mirrors triggered thereby from the rear side of the mirror unit;

14 and 15 are schematic side views of the angle ratios of

Focusing mechanism of the second mechanical transmission;

16 shows a schematic side view of the focusing mechanism of the second mechanical transmission to illustrate the beam path;

17 is a side view of a second preferred embodiment of the

Heliostats with a rotation axis for focusing on different targets;

Fig. 18: a plan view of differently positioned heliostats of the second

Common target embodiment, showing the orientation of the first mechanical transmission; FIG. 19 shows a three-dimensional detail representation of the second embodiment of the heliostat; FIG.

FIG. 20 shows a side view of a third embodiment of the heliostat, with a rotation axis and a pivot axis perpendicular thereto, for positioning the heliostat on different targets; FIG.

Figures 21A-C are side views of the heliostat of the third embodiment for various pivot angles of the axis J-J '; 22 shows a side view of the first mechanical transmission of the third embodiment of the heliostat, in particular the device for parallel displacement of the curved path; Fig. 23: a three-dimensional detail representation of the device for

Parallel displacement of the curved path of the third embodiment of the heliostat;

FIG. 24 shows a side view of the first mechanical transmission of the first and second embodiment of the heliostat, in particular the device for parallel displacement of the curved path; FIG.

Fig. 25: a three-dimensional representation of the mirror rows of the mirror unit; Fig. 26 is a side view of the mirror rows of the mirror unit, with one

Mirror rows in the on and off state;

Figs. 27-29 are three-dimensional representations of a power control mechanism for mirror rows;

Fig. 30 is a sectional view from the side of a first embodiment of a receiving element according to the invention;

Fig. 31A-C are sectional views of a solar fireplace and an absorber for

Liquids of a receiving element; and

Fig. 32: a sectional view from the side of a second embodiment of a receiving element according to the invention. 5, Preferred Embodiments

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Features of individual embodiments can be combined with features of other embodiments, even if this is not expressly illustrated. FIG. 1 shows a solar thermal system 100 for using solar energy with a heliostat 1 and an associated receiving element 3. In this case, the heliostat 1 reflects and focuses sun rays S, 2 onto a focal point which is located in the receiving element 3 via a reflecting and simultaneously focusing mirror unit 60 , In this case, the receiving element 3 is arranged in such a way that the reflected and focused solar beams 2 are directed onto an absorber 22 via a deflecting mirror 21. In the absorber 22 is preferably a conversion of solar energy into heat instead.

A first embodiment of a focusing heliostat 1 for using solar energy is shown in FIG. The heliostat 1 comprises a mirror unit 60 composed of a grid of small plane mirrors 7. The plane mirrors 7 concentrate the incident parallel sunlight onto the focal point in the receiving element 3.

The heliostat 1 further comprises a rocker frame 5, which is fixed to the skeleton 4 so as to be pivotable about an axis A-A on a fixed bearing. The axis A-A 'is aligned with the receiving element 3. On the rocker frame 5, the mirror unit 60 is fixed and therefore rotates with a rotation about the axis A-A 'with the rocker frame 5 with.

The mirror unit 60 is further pivotally mounted on the rocker frame 5 about an axis B-B '(see Figures 4 and 5) which is oriented perpendicular to the axis A-A' and preferably intersects the axis A-A '. Thus, the mirror unit 60 can pivot as a whole with respect to the rocker frame 5 about the axis B-B '. The movements about the axis A-A 'and B-B' make it possible to align the mirror unit 60 as a whole in the course of the day on the different position of the sun.

The individual plane mirrors 7 are mounted on the mirror unit 60 so as to be pivotable about the mirror row axis CC so as to occupy varying angles during the course of the day and in comparison to the other plane mirrors 7. The angles may differ from the angles of the same time of the previous day. With this adjustment possibility of the individual plane mirror 7 about the mirror row axis CC, it is possible to perfectly focus the mirror unit 60 on the desired To ensure focal point at different positions of the mirror unit 60 as a whole.

The focusing heliostat 1 used to track the position of the sun during the day only a single drive for rotating the rocker frame 5 about the axis AA 'and for simultaneous tilting of the frame 6 of the mirror unit 60 about the axis BB' and for pivoting the shown in Fig. 2 Mirror row axes CC The receiving element 3 serves to receive the concentrated light with a high efficiency. It therefore has a special inner geometry. The receiving element 3 has an adaptive or replaceable upper part 27, which can be adapted by means of different absorbers 22 to various applications and heat transfer (water, steam, gas), or heat storage medium (solid materials, stone, furnace material). The temperature of the absorber surface can, depending on the particular application, be between 50 and 2000 ° C. Due to the special directed irradiation by a heliostat 1 according to the invention, the receiving element 3 can be carried out correspondingly optimally adapted, which results in a very high thermal efficiency. In particular, advantageous light projection parameters result, so that beams coming from the focusing heliostat 1 include only a cone angle below 8-12 ⁰ to the basic projection direction of a central reference mirror 111. This advantageous projection property of the heliostat 1 results in that it behaves like a downsized solar power plant. It projects and focuses in one step, the light incident on the mirror unit 60 sunlight S and projects the beams 2 with a convergence of 8-12 ⁰ to the receiver 3. The receiving element 3 can be further lowered near the ground or even in the ground. A receiving element at the top of an exposed tower, as in conventional systems is therefore not necessary. According to the invention, the design of a receiving element 3 arranged at a fixed point can be spatially deeper and more complex and there is virtually no restriction with regard to inlet opening, size, degree of isolation, etc. A significant advantage of the developed solar thermal system 100 is that it is located far to the north Places that have low solar states, even at low outdoor temperature overall high efficiency can be achieved.

The mirror unit 60 of the heliostat 1 follows during the course of the day and over the seasons of the solar movement with the aid of a first mechanical transmission 120, which will be described below with reference to FIGS. 6 to 10. The first mechanical gear 120 transmits the pivoting movement of the rocker frame 5 about the axis AA 'to the pivotal movement of the mirror unit 60 about the axis BB' with respect to the rocker frame 5. The rocker frame 5 consists, as shown in Fig. 5, of an assembly of tubes welded together , The rocker frame 5 is provided on its underside with two pivot bearings, by which it can pivot on the skeleton 4 about the axis AA 'by substantially +/- 90 ⁰ . The first mechanical gear 120 is located at the left end of the rocker frame 5 in FIG. 5. The core element of the gear 120 is a control surface 14, which is aligned parallel to the sun track and is accordingly fastened to the main frame 4 so as to be adjustable in inclination and height. As shown in FIGS. 7-10, the control surface 14 is formed as a control ring that must be aligned parallel to the sun track. For this purpose, the control ring with threaded rods 62 or other variable in length components is attached to a support member 16. By adjusting the threaded rods 62, the control surface 14 is aligned parallel to the Sonnbahn depending on the site and direction of the target. This parallel orientation to the sun orbit must be set only once.

In order to adjust the control surface 14 to the maximum sun height of the respective day, its carrier element 16 is mounted parallel displaceably via a parallelogram bearing 15, 16 with four rods 15 of equal length on the basic frame 4. Every day once or every 2 - 3 days, the control surface 14 is to be set to a new height, which corresponds to the seasonal height of the plane of the solar orbit. This can be done manually or by means of a drive with the aid of a solar sensor or programmatically. By parallelogram storage 15, 16, the parallel alignment of the control surface 14 is maintained to the sun's path.

The control surface 14 serves as a raceway for a rolling wheel 13 which is rotatably mounted on a bracket 12, which in turn is pivotally mounted on a control arm 11. This storage mode, shown in detail in FIG. 10, ensures that the rolling wheel 13 always rolls in vertically on the ring of the control surface 14, irrespective of the angular position of the control arm 11 relative to the control surface 14. Thus, the Wälzrad 13, the control surface 14 depart exactly and the reading error is very low. As shown in Fig. 10, the bracket 12 to the control arm 11 on the summer or winter solstice occupy an angle of 23.5 °.

The control arm 11 consists of a substantially triangular construction of steel tubes at both ends sliding bearing 10 are rotatably mounted. A rotatable sliding bearing 10 is exemplarily shown in Fig. 6 individually three-dimensional. The control arm 11 is pivotably mounted on the mirror unit 60 via an axis E-E '(compare FIGS. 4 and 6) and rotates together with the mirror unit 60 about the axis A-A'. In this case, the rolling wheel 13 rolls on the fixed control surface 14 and thereby moves the control arm eleventh

The control arm 14 transmits its movement to two lever rods 9 which are guided longitudinally displaceably in the two sliding bearings 10. The lever rods 9 are in turn pivotally mounted on the rocker element 5 on an axis F-F '(see FIGS. 4 and 6) and connected to the support frame 6 of the mirror unit 60 via connecting rods 8.

The Wälzrad 13 (not shown) by means of spring pressure of two tension springs on both sides, between the lever rods 9 and the rocker frame. 5

are arranged, pulled to the control surface 14. With this mechanical transmission 120, a pivoting movement of the rocker arm 5 about the axis AA 'is converted into a pivoting movement of the mirror unit 60 about the pivoting axis BB with the rocker arm 5'. By the alignment and height adjustment of the control curve 14 is achieved that the incident sun rays S, the surface normal N of the mirror unit 60 and the reflected rays R of lying on the axis of symmetry mirror - for example, the reference mirror 111 - always run in an area a, as in Fig. 2 shown. This has the control technical advantage that the individual plane mirrors 7 during the tracking during the day to the optimum concentration of the sun's rays only about a single axis CC with respect to the mirror unit 60 must be varied and the preset pivoting of the plane mirror 7 about the axis DD '(see FIG 2) can be kept constant over the course of the day. In other words, the mirror unit 60 only needs to have a variable focus parallel to the CC axis, and the focus about an axis parallel to the DD 'axis may remain constant during tracking throughout the day.

As illustrated in FIG. 4, the surface normal N of the mirror unit preferably forms the angle bisector between the incident sun rays S and the reflected rays R of the reference mirror 111. In order to realize the precise bisection in the angle, it is preferable to have the geometric as shown in FIG

Conditions required. From Fig. 24 it can be seen that the distance x of the parallel axes E-E 'and G-G' and the axes E-E 'and F-F' is equal to each other. The position and distance of the axes G-G 'and E-E' to each other is also apparent from Fig. 9.

In the case of a clear, sunny sky, a drive motor (not shown) rotates the rocker frame 5 at sunrise from the center position shown in Fig. 2 in the direction of the sun with a rotation of ± 90 ° about the axis A-A '. On the basis of signals from solar sensors (not shown) arranged on the mirror unit 60, the angle of rotation of the rocker frame 5 about the AA "axis is set so that the sunrays always invade the surface a (see FIG always perpendicular to the CC axis, the pivot axis of the individual plane mirror 7. A drive motor pivots that Rocker frame 5 continuously synchronized with the sun throughout the day. In Fig. 2, the position of the heliostat 1 is shown at noon, in which the sun is at the highest point and the rocker frame 5 is in the center position.

Synchronously with the movement of the rocker frame 5 about the axis AA ', the mirror unit 60 is pivoted by the mechanical gear 120 about the co-rotating axis BB' in the course of the day and in the view of Fig. 4 from the illustrated mid-position (noon) for the morning in the clockwise direction and then back counterclockwise during the day. The consequences of the movement of the sun is thus achieved by keeping the sun's rays S in the plane a of the mirror unit 60. The current amount of solar radiation with respect to the plane a is accommodated by a variable focus of the mirror unit 60. For this purpose, the plane mirror 7 are pivoted about the mirror row axis C-C in the course of the day.

The parallel shift of the control surface 14 for adaptation to the sun paths in the course of the year is outlined in Fig. 3 at summer or winter solstice and for the equinox. The angular adjustment of the control surface 14 is dependent on the latitude of the site and thus the angle of the earth's axis at the site. The parallel displacement of the control surface 14 is such that, due to a midpoint mirroring by the first mechanical transmission 120, the control surface 14 at the summer solstice at its bottom dead center, at equinox in the center position and in the

Winter solstice is located at top dead center. In the middle position at the equinox the control surface 14 falls at horizontal level of the

Rocking frame 5 at lunchtime with the E-E 'axis together.

The setting of the variable focus of the mirror unit 60 in the course of the day via a pivoting of the individual rows of mirrors 70 from plane mirrors 7 or a respective curved mirror strip 72 about each axis C-C. This pivoting of the mirror rows 70 about the axis C-C takes place by means of a second mechanical transmission 130 as a function of the pivoting movement of

Mirror unit 60 about the axis B-B '. By the second mechanical transmission 130 For example, individually powered CC axles of the

Mirror rows 70 and their control superfluous.

An embodiment of a mechanical transmission 130 is shown in FIGS. 11-16. The mirror rows 70 are pivotably mounted on the mirror unit 60 about an axis C-C. The rows of mirrors 70 are pivotable independently of each other, to a variable focus of the mirror unit 60th

to provide that minimizes the aberration over the course of the day. As shown in Fig. 11 in a side view, 5 fixed cam plates 31 are mounted on the axis B-B 'with respect to the rocker frame. The

Cams 31 therefore do not rotate with mirror unit 60 about axis B-B '. On the circumference of these cams 31 lever arms 64 are guided, which are each connected to a row of mirrors 14. By turning the

Mirror unit 60 about the axis B-B ', the lever arms 64 slide continuously on the corresponding relative to the axis B-B' fixed cam 31 and transmit this movement on the pivotal movement of the mirror row 14 about the axis C-C. The free ends of the lever arms 64 are held by tension springs (not shown) on the corresponding cams of the cams 31.

The shape of the cams of the cam 31 is determined by the length of the corresponding lever arm 64 and the desired pivot angle of the mirror row 14 about the axis C-C at a given pivoting of the mirror unit about the axis B-B '. In principle, the rows of mirrors 14 furthest away from the pivot axis B-B 'experience a greater pivoting than the rows of mirrors 14 located further in the interior. A row of mirrors arranged centrally does not need at all or only little around the day

Mirror row axis CC to be pivoted. The resulting angular relationships at a pivoting of the mirror unit 60 about the axis BB 'are outlined in Figures 14 and 15. It can be seen that by the pivoting of the mirror rows 14 about the axis CC (angle Yi and Y ₂ ) despite different inclination of the mirror unit 60 about the axis BB ' (Difference angle β, the reflected rays R in the same focus

focus.

Focusing the rows of mirrors 14, thanks to the second mechanical transmission 130, does not require a separate energy requirement. The focus is also fully automatic and seasonally independent after installation and adjustment. In addition, perfect focusing is achieved without the flat mirrors 7 having to be tracked about a further mirror axis (axis D-D '). This significantly reduces the control effort of the overall system.

In the embodiment of the heliostat 1 of FIGS. 4-11, the focus, or the direction of the target, was on the axis A-A ', which was aligned substantially horizontally and to the south. Then, with continuous focusing, the axis H-H 'of the control arm 11 always points exactly in the direction of the sun (see Fig. 9).

In a second embodiment of the heliostat 1 according to FIGS. 17-19, the direction of the focus or the target can be changed. No further adjustments need to be made to the heliostat 1, in particular to the first mechanical gear 120. In this embodiment, this is

Backbone 36, and thus the axis A-A 'in the direction of the target, pivotable about the axis Ι-Γ. The focus function is completely retained.

The skeleton 36 and the mirror unit 60 attached thereto can be rotated about a vertical bearing on an axle 38 so that the axis A-A 'points in the desired direction. However, the position of the control surface 14 is maintained with respect to the installation site. This is done by the fact that the

Control surface on the parallelogram assembly 15, 16 and a bearing arm 37 is mounted on the axle 38, which is fixed to the ground and not with the

The basic frame 36 rotates around the axis Ι-Γ. Thus, the angular ratios described above with respect to the area a of the mirror unit are also complied with.

This is achieved by choosing the axis Ι-Γ to intersect the common intersection point of the axes Α-Α ', E-E', HH '. Further adjustments of the first mechanical transmission 120 are not necessary. The remaining components of the heliostat 1 correspond to those of the first embodiment described above.

In the course of a uninterrupted solar tracking, the

Projection direction of the heliostat 1 are rotated about the axis Ι-Γ. However, as shown in Figs. 18 and 19, the control surface 14 remains at a fixed distance and fixed direction with respect to the common intersection of the axes A-A ', E-E', H-H ', and Ι-Γ. Accordingly, optimum tracking of the mirror unit 60 about the axes A-A ', B-B' and C-C is obtained.

As in the first embodiment, the axis A-A 'is driven in a controlled manner by means of a solar sensor (not shown) on the mirror unit 60, so that the axis H-H' of the control arm 11 is constantly pointing in the direction of the sun. Upon rotation of the system about the axis Ι-Γ, the axis H-H 'of the control arm 11 is rotated slightly with respect to the remaining in position and position control surface 14. However, because the image is taken only when the axis H-H 'is aligned with the sun, the rocker frame 5 is slightly readjusted with respect to the axis A-A'. The post-correction about the axis A-A 'can take place automatically, because this post-correction corresponds to the usual sun tracking of the mirror unit 60. That The solar sensors that control the movement of the system can also perform this correction with respect to the rotation about the axis A-A 'also automatically. Accordingly, no additional equipment is required for the post-correction.

FIG. 18 illustrates that with the second embodiment of the heliostat 1 differently arranged targets can be illuminated. The rocker frame 5 rotates about the axis Ι-Γ in the desired direction (axis A-A '), the control surface 14 is fixed and remains aligned with respect to the sun. Thus, 1 different targets can be illuminated with a single heliostat 1, which are arranged in a plane. In addition, it is also possible, as shown, to illuminate a common target with several identical heliostat 1. In Figs. 20-24 and in Fig. 1, a third embodiment of a

Heliostat 1 shown, in which the projection direction is adjustable by two axes. This makes it possible to illuminate with a heliostat 1 differently arranged targets that do not need to be arranged in a plane. For example, with a heliostat 1 receiving elements 3 of individual apartments of a multi-storey building can be irradiated.

In Fig. 20 is a sectional side view of the pivotable about two axes heliostat 1 is shown. The skeleton 36 can be rotated in this embodiment about a substantially vertical axis Ι-Γ and pivoted about a perpendicular thereto arranged horizontal axis J-J '. Here, the bearing 39 of the axis Ι-Γ is pivotally mounted on a bearing 39. Thus, it is possible to align the axis A-A 'of the rocker frame 5 to any different targets, including superimposed targets.

As with the second embodiment, the control surface (14) must be aligned with respect to position and direction of the sun track here, too. Furthermore, the control surface 14 is again held in the common crossing point of the axes Α-Α ', Ε-Ε', H-H 'and Ι-Γ. When the skeleton 36 is pivoted about the axis J-J ', as shown in Figures 21A-21C, the control surface 14 is moved along. In this case, a parallelogram of pivotally interconnected holding rod pairs 41, 44 and 45 ensures that the

Orientation of the control surface 14 is maintained on the sun track.

As shown in FIG. 22, the control surface 14 is again over one

Parallelogram 15, 16 mounted displaceably parallel. The

Parallelogram 15, 16 is a tie on a 42 with a

Bearing arm 37 is connected, which is mounted on the axle 39, which can pivot with the skeleton 36 about the axis J-J ', but does not rotate with the skeleton 36 about the axis Ι-Γ. By the tie sheet 42, it is possible that the control surface 14 maintains its orientation to the sun, although the

Backbone 36 of the heliostat 1 pivots with respect to the axis JJ '. In this case, the left-side mounting 43 of the parallelogram arrangement 15, 16 in FIG. 20 is displaceably mounted in the retaining bow 42 and can be displaced by an upper retaining rod pair 45 with respect to the retaining bow 42 in curved bearing grooves 66 (see FIG. For this purpose, the lever 45 is pivotally connected to the bearing 43 about an axis MM '.

The upper holding rod pair 45 is pivotally connected at its lower ends respectively to a middle holding rod pair 44, which is pivotally connected at its center via a bearing about the axis K-K 'with the axis 39. At its second ends, the middle holding rod pair 44 is connected to a lower holding rod pair 41, which is mounted parallel to the axis 39 pivotally mounted on a stationary bearing 40.

The constant distance between the axes L-L 'and M-M' of the first lever 45 corresponds to the constant distance between the axes K-K 'and E-E'. The constant distance between the axes K-K 'and E-E' is ensured in the horizontal middle position of the rocker frame 5 by a connection with correspondingly dimensioned rigid parts of the skeleton 36 and the rocker frame 5.

The axes J-J ', K-K' and E-E 'are parallel to each other and each of them is perpendicular to the axis Ι-Γ. The distance between the axes K-K 'and L-L' corresponds to the distance between the axes E-E 'and M-M'. The axes J-J ', K-K', E-E ', L-L' and M - M 'are parallel to each other in any position. The distance between the axes K-K 'and L-L' corresponds to the distance between the axes L-L 'and M-M'.

When the heliostat 1 is pivoted about the axis J-J ', the longitudinal axes of the lower holding rod pair 41 and of the upper holding rod pair 45 always assume a position parallel to the axis I - Γ. The longitudinal axis of the middle holding rod pair 44 always remains in a horizontal position. In the course of the rotation about the axis J-J ', the axes KK' and LL 'always remain at the same height as the axes MM' and E-E '. Upon rotation about the axis JJ ', four shaft journals 68 of the bearing 43 are displaced in the arcuate grooves 66 of the retaining bow 42. As shown in Fig. 23, corresponds to the position and the arc of the arcuate grooves 66 of the tether 42 a circular arc about the axis E-E '. The radius of the

Circular arc corresponds to the distance between the shaft journal 68 and the axis E-E '.

The shaft journals 68 of the bearing 43 are thus in the arcuate grooves 66 of the retaining bow 42 by the movement of the holder rod pair 45 so

shifted as if they were rotatably mounted on the axis E - E '. In the

Control thus creates no angle error. The direction of projection always coincides with the rotation of the heliostat 1 about the axis J-J 'with the direction of the axis A-A'.

Now, if the heliostat 1, as shown in Fig. 21A, from its vertical position of Fig. 21B in the counterclockwise direction about the axis JJ 'pivoted (eg angle 98 ⁰ ), then pushes the lever 45, the bearing 43 with respect to

Tie bow 42 in the curved grooves 66 upwards, so that the orientation of the control surface 14 is maintained to the sun's path.

If the heliostat 1 as shown in Fig. 21C from its vertical position of Fig. 21B clockwise about the axis JJ 'pivoted (eg angle 82 ⁰ ), then the lever 45 pulls the bearing 43 with respect to the retaining bow 42 in the curved grooves 66th down, so that the orientation of the control surface 14 is again maintained to the sun.

It can be clearly seen from Fig. 22 that the angular position of the control surface 14 remains unchanged and is independent of the direction of the axis Ι-Γ of the system. It can also be seen that consequently the direction of the axis HH 'remains constantly aligned with the sun. In this rotation of the system about the axis JJ 'therefore no adjustment of the mirror unit 60 needs to be performed because the first mechanical gear 120 compensates for this movement and keeps the control surface 14 in the correct position. Further adjustments of the first mechanical transmission 120 of the third

Embodiment are not necessary. The remaining components of the heliostat 1 correspond to those of the embodiments described above. In a further embodiment shown in FIG. 25, the flat mirrors 7 of the mirror rows 70 shown in FIG. 2 are replaced by special ones for each

Mirror row 70 provided bent reflective metal sheet strips 72 replaced. Their curvature corresponds to the average focal distance. The use of the metal sheet bands 72 improves the efficiency of focusing. The metal sheet strips 72 have a different depending on the mirror row 70

Curvature and, like the flat mirrors 7, are mounted on mirror row axes C-C 'by means of an axis 17 on the mirror unit 60.

In a further embodiment, which is illustrated in FIGS. 26-29, the heliostat 1 can control the power by switching the power on and off

Perform mirror rows 70. Accordingly, the heliostat 1 can be quickly adjusted to the currently required amount of heat or light without the

Focusing direction of the mirror unit 60 to change. By adjusting a lever system, the power of the heliostat 1 can be gradually reduced from 100% to even 0%, resulting in a

Power control mechanism is enabled.

The power control mechanism comprises Wipparme 52 for each mirror row 60. The Wipparme 52 are rotatably mounted on the axes 17 of the mounted on the mirror unit 60 mirror rows 70. A connecting rod 51 is rotatably connected to the Wipparmen 52 and connects the Wipparme 52 and at the same time

Mirror rows 60 together. The lever arm 64 is rotatably mounted on the axis 17 of the mirror row 70 in contrast to the previously described embodiments. The power control mechanism may be driven by a main movement arm 57 so as to engage mirror rows 70 about the axis C-C

panning that they no longer focus the incoming sunlight towards the target. As can be seen in Figures 28 and 29, a T-shaped holder 54 is rotatably attached to each axis 17, via which the pivoting movement is introduced to the mirror row 70. In the holder 54 two screws 56 are screwed, with which the tilting of the mirror row 70 can be finely adjusted.

In Fig. 29, the normal operating state is shown. Here, the holder 54 is moved via a button 55 of the lever arm 64, which abuts against the right-hand set screw 56. The mirror row 70 is tensioned for this purpose by means of a spring (not shown) in Figures 28 and 29 in a clockwise direction.

Accordingly, the set screw 56 of the holder 54 abuts on the button 55 and the mirror row 70 can be focused on the target according to the position of the lever arm 64 as described above in detail about the axis C-C '.

FIG. 29 shows the state in which the mirror row 70 has been turned out of focus. By pivoting the main movement arm 57 downwards (compare Fig. 26), the connecting rod 51 is moved downward and the Wipparme 52 pivoted downward. Accordingly, the button 53 of the Wipparms now touches the left adjusting screw 56 of the holder 56 and rotates the axis 17 in the counterclockwise direction about the axis C-C Thereby, the mirror row 70 is also rotated counterclockwise out of focus. This condition is shown for the top three rows of mirrors 70 in FIG. The solar rays incident on these rows of mirrors 70 are not reflected to the target and thus the performance of the heliostat 1 decreases. A major advantage of the power control mechanism is that the

Rocker frame 5 and the mirror unit 60 remain in the set sunshine position, even while single or all rows of mirrors 70 are turned off. As a result, the full power of the heliostat 1 can be switched on again without delay. The focusing heliostat 1 can be switched on and off quickly and safely by this mechanism, as well as for each

Partial load can be adjusted.

The components of the receiver element 3 are shown in detail in FIGS. 30-32. A funnel-shaped Einstrahlkanal 25 allows the incident light into Reception element 3 occur. A flat deflecting mirror 21 is located in the irradiation channel 25 which highly reflects the preconcentrated light in front of the focal distance in an upward-facing solar chimney 24. The incident light is in the upper part of the solar fireplace 24, denser and more concentrated and reached in the area of a shoulder portion 28 its focus.

At the top of the solar chimney 24 is the constricted shoulder part 28, which widens upwards in a plate shape again. In the area of the focus itself, an absorber 22 is arranged. In the embodiment illustrated in Figures 30 and 31A-31C, the absorber 22 is a hollow body tubular absorber for heating liquids. Preferably, the pipe absorber has the shape of a hive. As shown in Fig. 32, the absorber 22 may also consist of a brick oven 29, 30 or other heat storage means. The inner surfaces of the solar fireplace 24 are mirrored. The absorber surface

22 is located at the highest point of the solar fireplace 24, whereby it is closed at the top. The concentrated light passes through the shoulder portion 28 and is absorbed in the absorber 22 to 93-95%. Only 5-7% of the light is reflected.

A small portion of the sun's rays (5-7%) is reflected by the surface of the absorber 22, in part again on the surface of the absorber 22 and partly on the specially designed inner mirror surfaces of the solar fireplace 24, from where the majority of the sun's rays return to the Absorber surface 22 is reflected. Only a small part of the light is reflected by the shoulder portion 28 of the solar fireplace 24, which is the only emission direction.

Below the shoulder portion 28 are a number of annular mirror surfaces

23 reflect a part of the reflected back from the absorber 22 sun rays back to the absorber surface 22.

Fig. 31A shows the possible light and radiation directions for the

Reflection from the center and Fig. 31B from a general point of the absorber 22 from. The majority of from any point of the absorber 22 reflected back light is either again directed directly onto the surface of the absorber 22 or thrown back from the inner mirror surfaces 23 to the absorber 22. Within the cone angle X and outside the cone angle Y lying, sunbeams reflected back in the annular direction are reflected back to the absorber surface 22 of the mirror surfaces 23 after one or more reflections. Rays lying within the cone angle Y strike the deflection mirror 21 and leave the receiving element 3.

Due to the illustrated receiving element 3, only 3-5% of the light reflected by the absorber 22, which constitutes only 5-7% of the total irradiation, emerges from the receiving element 3 again. This means that only a very small part (for example, a maximum of 0.35%) of the incident total radiation is lost.

The heat loss is also minimized by the chimney-shaped, closed structure of the solar fireplace 24, since this structure reduces the internal air circulation. In this case, the stratification of the air temperature in the interior of the solar fireplace 24 coincides with the thermal stratification of the heat source located at the highest point (the absorber 22). In the immediate vicinity of the highest point absorber 22, the air temperature is highest, so that the heat loss of the absorber 22 is minimized.

In the solar fireplace 24 down the air temperature is rapidly decreasing.

Accordingly, the convective temperature loss is also minimized in the direction of the radiation channel 25 of the receiving element 3.

Since the receiving element is at a fixed location, the thickness of the insulation around the absorber 22 and around the solar chimney 24 is not limited. Preferably, the receiving element 3 has a very well insulated housing 26, 27. The heat loss through the insulation is therefore completely reduced by appropriate insulation or by a weather-resistant housing. The receiving element 3 is adaptive in that the absorber 22 is changeable. It is therefore easy to produce, modify, deliver and assemble. The geometry of the receiving element 3 aims to form a quasi-perfect light and temperature trap. With the special geometric design and mirror surfaces 23 of appropriate quality, the concentrated light can heat the absorber or oven up to 2000 ° C with minimal temperature loss, depending on the concentration of light. The receiving element 3 can therefore also be used as a specially designed oven, melting furnace, kiln or the like.

In the case of use as an oven, both internal and external heating can be realized. FIG. 32 shows a version of an inner one

Heating, wherein the solar radiation impinges directly on the inner wall 29 of the furnace. This means that the oven can be heated the fastest, with the least loss, directly.

By heating the material 29, 30, which forms the wall of the furnace, the furnace can be kept constantly at a rather low temperature without constant irradiation. Furnaces, on the other hand, which require a temperature close to 100 ° C, require constant light radiation.

The receiving element 3 can work with any heat transfer mediums that receive the efficiency of the receiving element 3. The receiving element 3 can be arranged directly at ground level (inside or outside) or even underground. An inner or subterranean placement of the

Receiving elements 3 extends its life, since the typical

Weather influences of the environment such as UV radiation, frost, rain, dew can not affect the receiving element 3 so intensely. In addition, the heat transfer medium can easily be kept frost-proof.

Claims

claims

Heliostat (1) comprising: a) a mirror unit (60) for reflecting and focusing sun rays (S) on a target (3); b) wherein the mirror unit (60) is rotatably mounted about a first main axis (Α-Α '), which is always aligned in the direction of the target (3); and c) wherein the mirror unit (60) about a second major axis (Β-Β ') is rotatably mounted, which is perpendicular to the first main axis (Α-Α') and perpendicular to the surface normal (N) of the mirror unit (60) and arranged with the mirror unit (60) rotates about the first main axis (Α-Α '); wherein d) the rotational movement of the mirror unit (60) about the second main axis (Β-Β ') by means of a first mechanical transmission (120) by the rotational movement of the mirror unit (60) about the first major axis (Α-Α') is effected.

2. Heliostat according to claim 1, wherein the first main axis (Α-Α ') is arranged so that upon rotation of the mirror unit (60) about the first main axis (Α-Α') sun rays (S) on a symmetry line ( L) of the mirror unit (60), which is perpendicular to the second major axis (Β-Β '), are incident and reflected therefrom, always lying in a surface (a) which is separated from the line of symmetry (L) and the surface normal (N ) of the mirror unit (60) is clamped. Heliostat according to one of claims 1 or 2, wherein the first mechanical transmission (120) has a with respect to the first main axis (Α-Α ') fixed control surface (14) having a on the mirror unit (60) hinged taker (11, 12 13th ) to mechanically cause the rotation of the mirror unit (60) about the second major axis (Β-Β ').

A heliostat according to claim 3, wherein the control surface (14) is adjustable in orientation so as to be aligned parallel to the plane of the sun orbit.

A heliostat according to any one of claims 3-4, wherein the control surface (14) is parallel displaceable in order to adjust its position to the seasonal height of the plane of the sun track.

A heliostat according to any one of claims 1-5, wherein the mirror unit (60) comprises rows of mirrors (70) each consisting of a plurality of plane individual mirrors (7) or a curved mirror strip (72), the mirror rows (70) being individually aligned around a mirror row axis (70). CC), which is arranged parallel to the second main axis (Β-Β '), are rotatably mounted on the mirror unit (60).

Heliostat according to claim 6, wherein the rotational movement of the mirror rows (70) about the mirror row axis (C-C) by means of a second mechanical transmission (130) by the rotational movement of the mirror unit (60) about the second major axis (Β-Β ') is defined.

A heliostat according to claim 7, wherein the second mechanical gear (130) has individual cam tracks (31) for driving the individual rows of mirrors (70) with respect to the second main axis (Β-Β ') are fixed and which rotate with the mirror unit (60) about the first main axis (Α-Α').

9. Heliostat according to one of claims 1-8, wherein the tracking of the heliostat (1) in the course of the day exclusively by a

Driving the rotation of the mirror unit (60) about the first major axis (Α-Α ') takes place.

10. Heliostat according to claim 9, further comprising a rocker arm (5) which the rotation of the mirror unit (60) to the first

Main axis (Α-Α ') executes.

11. Heliostat according to one of claims 1-10, wherein a skeleton (36) of the heliostat (1) is rotatably and / or pivotally mounted to differently arranged targets with a single

Heliostats (1), wherein the orientation of the control surface (14) of the first mechanical transmission (120) is maintained to the sun orbit for all different targets. A heliostat according to any one of claims 6 to 11, further comprising a power control mechanism in which rows of mirrors (70) are individually pivotable about their mirror row axis (C-C) to no longer focus the sun's rays (S) on the original target (3).

13. receiving element (3) for receiving and for absorbing focused sunbeams (2), comprising: a) an absorber (22, 29); b) a radiation channel (25); and c) annular reflection surfaces (23) which are arranged on the wall of the Einstrahlkanals (25) so that they reflect back from the absorber (22, 29) reflected radiation back to the absorber (22, 29) out.

14. receiving element (3) according to claim 13, further comprising a deflecting mirror (21) in the Einstrahlkanal (25), which directs the sun's rays in a to the jet channel (25) upwardly angled solar fireplace (24) to the absorber (22, 29) out.

15. System (100) for converting solar energy into thermal energy, comprising at least one heliostat (1) according to any one of claims 1-12 and at least one receiving element (3) according to one of claims 13 or 14.