EP2663814A2

EP2663814A2 - Device and method for concentrating solar energy radiation and converting the same into heat

Info

Publication number: EP2663814A2
Application number: EP11794635.0A
Authority: EP
Inventors: Vladan Petrovic
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-11-16
Filing date: 2011-11-16
Publication date: 2013-11-20
Also published as: DE202010015433U1; WO2012065725A3; WO2012065725A2

Abstract

Disclosed is a concentrator that can track the position of the sun, concentrates solar energy radiation in a focal point zone (4), and comprises reflectors (1) which are fixedly oriented relative to one another. In order to reflect the sunbeams using the reflectors, a plurality of reflecting outer surfaces (1a) is arranged in such a way that the outer surfaces are at least partially located inside each other and concentric to each other at least approximately in the shape of truncated cones or segments of truncated cones having different inclinations, resulting in the sunbeams being focused on a significantly smaller surface, namely the focal point zone (4), after being reflected.

Description

Apparatus and method for concentrating solar energy radiation and for converting to heat

FIELD OF THE INVENTION

The invention relates to a new technical concept for concentrating the solar energy, in particular at a high temperature level. The concentrated solar energy can e.g. in a long-term heat storage at a high temperature level as heating energy for the winter months held or it can be used for continuous power generation throughout the year.

By concentrating solar energy, the energy of a heat storage medium can be increased and the energy efficiency of the system can be significantly increased when it is used. Today, various researches and developments are carried out worldwide to save solar energy over longer periods, but with little success.

CONFIRMATION COPY TECHNOLOGICAL BACKGROUND

The problems in the energy supply of the world are increasing, especially due to the incidents that occur more frequently in existing nuclear power plants. It is therefore forced in a relatively short time the whole concept of energy supply to renewable energy in a practical way. Today's solar power plants meet the requirements placed on them insufficiently. There are few places on earth where the sun shines 365 days x 8 hours a day. According to the current state of the art, even on sunny days, solar energy can not be used 24 hours a day, e.g. Generating electricity from solar energy without having to use energy from an additional energy source. In more recent times, solar thermal power plants have been used in solar thermal power plants, so that these power plants can also be operated in cloudy weather or after sunset. To bridge the sunless times with energy, various heat storage systems are currently being developed.

The concentration of sunlight and the storage of this energy would have to be adapted to one another in order to obtain a compact unit

Solar thermal power plants with sunlight concentration

These power plants use concentrating collectors to concentrate the incoming sunlight. So-called solar farm power plants use line concentrators, which focus the solar radiation on a focal line, while in solar tower power plants and Paraboloidkraftwerken the radiation of the sun is concentrated with point concentrators on a focal point zone. The achievable useful temperatures of these types of energy production are different. Solar farm power plants

Solar power plants are understood to be those with parabolic trough collectors which consist of arched or multiply divided mirrors which concentrate the sunlight onto an absorber pipe running in the focal line of the parabolic trough. Depending on the type of construction, the length of such collectors is between 20 and 150 meters. In the absorber tubes, the concentrated solar radiation is converted into heat and released to a circulating heat transfer medium. For reasons of cost, the parabolic troughs are usually uniaxially sun-tracked, with the focal line coinciding with the axis of rotation. They are therefore arranged in a north-south direction and track the sun from east to west during the course of the day. The collector field of a solar power plant consists of many parabolic trough collectors connected in parallel. A secondary mirror can be provided above the absorber tube, that is to say on the sun side, in order to reduce the emission effects of the absorber tube.

Parabolic trough collectors work up to 400 ° C process temperature which is sufficient only for direct steam generation. This temperature range (400 ° C) is not enough to save the heat energy economically long term. Concentration ratio for parabolic troughs is less than 100. The low concentration ratio accordingly causes low temperature of the heat transfer medium.

The heat transfer medium used is either thermal oil or superheated steam. In thermal oil systems temperatures of up to 390 ° C can be reached, which are used in a heat exchanger for steam generation. Direct steam generation (DISS = Direct Solar Steam) does not require such heat exchangers as the superheated steam is generated directly in the absorber pipes. This allows temperatures of over 500 ° C. Solar power plants have been commercially operated since 1984. The nine SEGS (Electric Electricity Generation System) power plants in southern California produce a total of 354 MW of power. Another power plant with a capacity of 64 MW is being built in Nevada. This type of power plant is rated at 14 percent. Andalusia is currently building the largest solar power plant in Europe, Andasol 1.

Fresnel Mirror Kolektoren

In addition to parabolic trough colectors (PRK modules), Fresnel mirror colectors (FSK modules) are also used. They have absorber tube a secondary mirror and a variety of one-dimensional tracked mirrors. Fresnel mirror collectors also have a low concentration ratio and use a liquid heat transfer medium. Solar power plants according to this concept operate in the moderate temperature range, are suitable for direct steam generation and less suitable for long-term heat storage.

Solar tower power plants

In solar tower power plants, solar radiation is concentrated on a central absorber with the aid of hundreds or thousands of automatically positioned mirrors (heliostats). The absorber is mounted on a tower and converts the radiant energy into heat. Solar tower power plants focus on a focal point. The temperatures therefore reach significantly higher values than with solar power plants. In this way, process heat of almost any temperature can be generated and used to accelerate chemical processes. As a rule, however, the heat generated in the absorber is used by a steam or gas turbine power plant to generate electricity. The maximum possible temperatures are around 1300 ° C. Heat transfer medium is either liquid nitrate salt, water vapor or air.

The largest existing plants are "Solar Two" (10 MW, working temperature: 290-570 ° C) in California and research facilities in Almeria (Spain) .Julch, Germany, started construction of a solar tower power plant in July 2006, 1.5 MW To bring performance. Solar tower power plants perform much better the conditions for light concentration at high temperatures, so there is much better way to store the heat energy at high temperatures. These power plants have a high concentration ratio. To achieve a high concentration ratio you need many reflectors (plane mirrors). Tracking the many mirrors according to the position of the sun, however, is extremely time-consuming.

Paraboloid Power Plants Paraboloid mirrors are mounted on two axles rotatably mounted on a frame and reflect the sunlight onto a focus-mounted heat receiver. This design is very compact and makes it possible to interconnect any number of these modules to a large solar power plant. The mirrors are designed with a diameter of 3 to 25 meters, which achieves powers of up to 50 KW per module. The modules are also suitable for decentralized energy supply in remote regions. In Dish Stirling systems, the receiver is followed by a Stirling engine, which converts the thermal energy directly into mechanical work. Due to the high efficiency of more than 30 percent, these systems are already well developed.

In the rarely used Dish Farm plants, the focal point is an absorber in which a heat transfer medium is heated and used to generate steam. For this purpose, several paraboloid must be interconnected.

Paraboloid power plants are better suited for generating the high temperature heat which can be kept in a heat storage with a larger storage capacity. It is disadvantageous that the absorber must be positioned in the focus of the parabolic mirror, so that a part of the surface of the parabolic mirror is lost by the shading. According to this concept, smaller units can be designed which can be considered an advantage compared to tower power plants. The parabolic mirrors are tracked in three axes to the sun. can be achieved by the large concentration ratio and thereby high temperatures can be achieved.

In order to ensure the continuity and thus the required reliability of the energy supply when using solar energy, the storage of solar heat is unavoidable. In order to achieve a large storage capacity, the concentration temperature of the sun's rays must be high (order of magnitude from 800 ° C). In this sense, it is necessary to specify a concentrator for solar radiation, the u. A. the long-term heat storage is adjusted. For a more decentralized use of solar energy, the compactness of the system is of particular importance. In a more centralized use of solar energy, questions of the controllability of tracking very large concentrators according to the position of the sun are particularly significant. It is also desirable to provide a solar energy utilization system which concentrates solar energy to a maximum temperature by means of a concentrator, then transfers the heat in an absorber to the heat transfer medium and heat energy to the heat transfer medium Heat storage mass gives off, which is located in a heat storage and thereby heats the heat storage mass up to a maximum temperature of about 1000 ° C. The heat storage should be insulated so that the heat energy can be kept available over the long period of time (several months to half a year) with low heat losses.

PRESENTATION OF THE INVENTION

According to the invention, a total of the solar station nachführbarer concentrator for concentrating solar energy in a focal zone by means of fixedly oriented reflectors is provided. For reflection of the sun's rays by means of the reflectors, a plurality of reflective mantle surfaces in the form of a truncated cone or in the form of segments of truncated cones with different inclinations is used. The reflectors with their reflective lateral surfaces are at least partially in one another and concentric with each other arranged that the sun's rays are focused after reflection on a much smaller area, namely on the focal zone. The invention is based on the basic idea of arranging the mirror arrangement of the concentrator of arcuate and approximately parallel to one another, that is, more or less concentric circles, arranged, essentially totally reflecting strip elements, such that the totally reflected sunlight in a focal spot focused on a solar energy receiving unit. The totally reflective ring or partial ring surfaces are preferably arranged nested to one another, whereby u. A. A small depth of the concentrator results Between parallel adjacent totally reflecting ring or partial ring surfaces can, depending on their radial distances from each other and their angles of inclination relative to each other and relative to the circular surface normal, the total incident and totally reflected sunlight to a relatively small focal spot (focal zone) be focused. If this happens on the sun-downstream side of the concentrator, an extremely compact design and a particularly high degree of utilization is achieved; Any shading of the solar radiation by a solar energy receiving unit, such as by an absorber, is omitted in such an arrangement. In principle, the inclinations of the concentric arcs of reflectors with respect to the circular area normal can all be the same size. However, in order to achieve the smallest possible focal zone, these angles become increasingly smaller radially inward. The solar energy receiving unit can be performed with the mirror assembly, ie the entire concentrator with, ie follow the position of the sun; it can also be arranged stationary if, as shown by way of example according to FIGS. 17A-H, the center of rotation and pivot of the concentrator is located sufficiently close to the focal zone.

The central area of the concentrator can remain free of reflectors and, for example, completely or partially direct light incidence on the solar energy receiving unit be used. Alternatively or additionally, at least one further concentrator of a similar or different design may be provided in the central region of the (first) concentrator, in order to also focus incident sunlight in this region on the solar energy receiving unit.

In principle, the reflectors can be arranged in a plane, in particular in a circular ring plane. If the radially inner reflector arcs are arranged closer to the sun than the radially outer ones, then u. A., achieved at the same radial widths of the reflectors lower shading.

By the invention u. A. achieves that

• the concentrator as a whole can be tracked biaxially with little effort

• a large concentration ratio of z. B. 400 to 1000 can be reached with comparatively little effort,

The concentrator is comparatively less susceptible to wind forces even with a large area,

• the reflective surface of the concentrator is easy to clean,

The surface of the concentrator can be designed almost as large as desired,

· The weight of the concentrator can be kept relatively small,

• shading of the concentrator by the absorber can be completely avoided,

• As a heat transfer medium from the absorber to a heat storage, eg.

B. by air, only short transport routes are required,

· The overall construction is simple and possible with comparatively low production costs,

• The system can also be implemented as a decentralized compact unit.

It is now possible to carry out the invention in various ways, as it u. A. from the dependent claims. The concentrator can have two concentric support rings (instead of rings, polygons consisting of segments made, for example, of square tubes or round tubes) can be provided. ways that form an outer ring and an inner ring. The support rings can be connected to each other by means of radially arranged webs. The webs can be connected to the support rings by means of the screw connection. They carry the reflectors, which may consist of flat material and preferably have mirrored surfaces which are shaped or assembled in the form of a circular truncated cone. The mirrored surfaces can be arranged at a certain distance from each other and concentric with each other between the two rings of the concentrator. The mirrored surfaces can be inserted and fastened in the slot-shaped cutouts provided in the webs. Each slot opening in the lands is arranged at a different angle to correspond to the inclination of the generatrix of the truncated cone. The inclination of the surface line of the mirrored surfaces is determined so that the solar rays are focused on the surface of the absorber after the reflection from the mirrored surface. When the sun's rays fall onto the absorber surface, they are converted into heat. Absorber plate can be made by casting so that the cup-shaped cavities are on one side (side of the sun) and the ribs on the other side. The sun's rays are trapped in the cavities, where they are converted into heat and can not be (partially) reflected outwards. Heat conduction heats the fins, and then transfers the heat of the sun from the fins to the passing air. The entrance to the sun's rays into the absorber is covered with a heat-resistant glass (made of quartz glass). This prevents the convective flow of air from the absorber plate to the outside. By covering the entrance of the sun's rays into the absorber, the space between the absorber surface and the heat-resistant glass will be completed. Of course, a relatively small portion of the sun's rays passing through the glass pane (due to the soiling of the glass pane) is converted into the heat. Care must be taken that the glass is sufficient must be positioned far from the absorber surface so that the solar rays converted into the heat get lower temperature than the maximum allowable temperature of the glass sheet (800 ° C) is. The concentrator is tracked to the sun after azimuth and after elevation. The sun's rays fall perpendicular to the projection surface of the concentrator.

The focal point of the concentrator is given and is measured as the distance between the lower edge of the outer ring of the concentrator to the focal point. Depending on the distance of the focal point, the inclination of the mirrored lateral surfaces of the truncated cones is determined accordingly. Each mirrored surface of the truncated cone has a different angle of inclination.

If air is selected as the heat transfer medium, the absorber is provided with one inlet and one outlet opening for the air flow. The pipe for the air flow is made of heat-resistant steel and for the inflection points of the piping flexible high-temperature hose pipes are considered at the concentrator. In the inner ring of the concentrator, a drive motor is provided which brings an arm with the water nozzles at certain time intervals in rotating motion to clean the mirror surface.

It is expected that the temperature of the finned surface of the absorber can reach about 1000 ° C and accordingly, the air flow is heated to the temperature of 900 ° C after the absorber.

The mirrored surfaces can be made in various ways. The mirror can be made of polished aluminum sheet, mirrored foil or, for example, metal-clad cardboard. As a mirror surface also polished stainless steel sheet can be used. For large installations, appropriate moderately polished aluminum sheet to use or black sheet with the glued mirror foil. Aluminum sheet has the advantage that the whole construction is lighter and therefore the costs can be significantly reduced. The whole spectrum of designing the mirrored surfaces on a concentrator is extremely diverse. One can also use the flat mirrors, for example, in that they are made of segments and arranged in a circle next to each other. It must be ensured that the width of each segment is less than or equal to the diameter of the focal point. The use of a simple aluminum foil which is inserted between two thin glass panes and pressed together by means of the screws presses the two glass panes together become. This prevents the outside air from coming into contact with the mirrored aluminum surface to prevent oxidation of the aluminum foil.

The design of the basic structure of the concentrator can be done in different ways:

In a first embodiment, this is that the concentrator rotates about a vertical axis which is centered to the turning circle. On the outer ring of the concentrator two shafts with ball bearings are provided which carry the concentrator and bring in rotation to elevation. The ball bearings are built into the housings and the housings are fixed to two horizontal steel plates. The steel plates sit on an arch-shaped carrier which is set centrally in the middle by means of a shaft.

Towards the center of the arcuate support a vertical axis is positioned with two ball bearings and brings the arcuate carrier in rotating motion. On the concentrator ring, the holders for the absorber are provided which hold the absorber in the correct position as the focal point. There are a total of two drive systems provided and indeed after azimuth and after elevation. The tracking to the azimuth takes place via the drive system which drives the concentrator about the right axis rotates and tracking after elevation via the drive system that rotates the concentrator around the horizontal axis.

The temperature in the absorber depends on the concentration ratio (the ratio of the concentrator area to the area of the focal point, in the concentrator according to the invention, the concentration ratio of 400 to 1000 and even more if required). The absorber is cooled by means of the air flow. The air flow is by means of a radial fan which is suitable for high air temperature promoted. The air flow flows between the ribs located at the bottom of the absorber plate and are poured together with the absorber plate by the casting process as a complete unit. The heat generated by the sun is transmitted by means of the ribs to the passing air. The heat from the air stream is then released, for example, to a heat storage mass.

In another embodiment, the concentrator is mounted on a rotating carousel which rotates on a circular path by means of the rollers and tracks the concentrator in azimuth. The carousel consists of two supporting pillars, which are made of square tubes, for example. The concentrator is supported on the supporting columns by means of the ball bearings and their housings and can be rotated about the horizontal axis. By rotating the concentrator around the horizontal axis, the sun can be tracked for elevation. According to this concept, it will be possible to build the large concentrators with a large concentration area (eg 8000 m ² ). For large units, it will be possible to provide the railroad tracks instead of circular concrete belts for rotating the carousel. In the center of the circle from the carousel is a massive vertical shaft which is equipped with two ball bearings so that any forces from the wind can be absorbed by means of this shaft. For the shaft, a foundation made of reinforced concrete is provided. The new technical concept of the absorber is of inherently inventive significance. The absorber can consist of a cast iron cast iron casting plate, wherein during the casting process a proportion of components which are suitable for high temperatures is added so that the casting plate remains stable at the temperature of 1100 ° C.

From one side of the cast plate, the holes are provided in close proximity to each other into which the sun rays fall, are reflected within the hole one to two times and converted into the heat. From the other side of the cast plate, the longitudinal ribs are provided which form a compact unit with the perforated cast plate so that heat converted by the sun rays is conducted to the ribs. Between the ribs, the air flows at a given flow rate and heats up to 900 ° C. The space above the cast plate is closed so that convective flow from the cast plate to the outside can not occur. The entrance opening for the sun rays is covered with a glass pane which is suitable for the high temperatures. The glass pane lies on a frame made of square tubes and is firmly attached to it. The square tubes are made of heat-resistant steel.

The whole absorber is placed in a box whose outer walls are paved with insulating bricks made of refractory stone. The sun tracking of the concentrator is in the sense of this invention a new solution to the problem and of inherently inventive significance. Namely, the sun tracking runs to "combined control".

"Combination control" means that the position of the sun to earth, can be "rough" (near) using a sun chart (in the form of a softwares) for a given location direction and altitude of the sun, for any date and any time determine. In addition, for the full hours, the sun positions can be determined for all days of the year. For each time by means of the software, the position of the sun is almost determined. The precise solar tracking of the concentrator results from four measuring points which are positioned within the absorber and give the temperature difference from each other. The position of the concentrator results from the minimum temperature difference between the four points. Thus, the bundle is controlled by the sun's rays toward the center of the absorber plate. As a result, the possible errors are avoided by the use of the photocell.

The connection of the absorber with a heat storage or with a consumer by means of the pipes is of independent inventive importance. There are some places on the pipes, which are firmly connected with concentrator (turning points) which must be movable. The air circulation supply line is laid in a larger diameter pipe and the space is filled with micronised ash. The micronized ash serves as insulation for the air line. At the outlet opening of the air line, a connection is provided on which a flexible hose, suitable for high temperatures, is connected by means of the pipe clamps. The heat-resistant tube serves as a connecting piece between two solid steel tube segments in the inflection point. A turning point is in the sun tracking azimuth and the other turning point is in the tracking after elevation available. There are a total of four short flexible hoses required to allow the rotational movement of the concentrator and with him firmly connected pipes. Two hose segments are provided in the air supply in the absorber (azimuth + elevation) and two after the absorber (azimuth + elevation). The isolation concept of the movable tube segments is also the relevant subject of this invention. The above-mentioned and the claimed and described in the embodiments described components according to the invention are subject to their size, shape design, choice of materials and technical design no particular exceptions, so that the selection criteria known in the field of application can be applied without restriction

Further details, features and advantages of the subject matter of the invention will become apparent from the subclaims, as well as from the following description and the accompanying drawings, in which - exemplary - embodiments of the sun's position total nachführbare concentrators are shown. Also, individual features of the claims or of the embodiments may be combined with other features of other claims and embodiments.

BRIEF DESCRIPTION OF THE FIGURES: is shown the schematic diagram of a mirror designed as a circular truncated cone; on the inside of the truncated cone may be glued a mirrored film, so that the whole truncated cone is formed as a mirror;

Fig. 1A is a schematic diagram of a segment shown as a development of the truncated cone shell as a circular ring cutout whose radius R1 and R2 come from a front view and H from a side view;

Fig. 1B is a schematic diagram to illustrate the composition of individual

Circular ring cutouts for the formation of the mirrored truncated cone; Fig. 1 C schematic representation of a mirrored truncated cone in plan view, composed of a plurality of circular ring segments;

Fig. 2 in a modification of Figure 1, is a concentrator consisting of several

Truncated cones, concentric with each other and arranged one inside the other;

Fig. 2A for clarity, Figure 2 shown in plan view; Representation of the area ratios on a concentrator (assuming D = 10 m diameter of the concentrator), projection surface of the concentrator, projection of the mirrored surface, mirrored surface, ratio of the mirrored surface to effective area and the efficiency of the projection surface;

Front view of a concentrator with Absober and support column ("first embodiment", rotation of the support column about a stationary axis);

Vertical sectional view of the concentrator with absorber (line V-V according to Fig. 4);

FIG. 6 shows a representation according to FIG. 5 with focused sunrays falling onto the absorber; FIG.

Figure 7 is a schematic representation of the inner and outer concentrator ring with webs. 8 is a vertical sectional view of the inner and the outer concentrator ring and the radially arranged the reflectors bearing webs;

Fig. 9 is a schematic representation of a web with slot-like recesses which are arranged at different angles of inclination;

10 shows a front view of a concentrator (without reflectors) with absorber according to a "second embodiment" (truss segments are provided instead of the outer ring), Fig. 10A shows schematically the assembly of the circular segments of the reflectors in a concentrator according to the "second embodiment"; Fig. 1 1 representation of fluid lines on the concentrator and their connection to the absorber by means of flexible connecting lines;

Fig. 12 is a schematic representation of the support frame assembly of a

Large diameter concentrator of e.g. 30 to 100 meters;

13 shows a representation of a rotary carousel according to the "second embodiment";

Fig. 13A track for the rotary carousel for large concentrators;

Fig. 14 Front view for concentrator, rotary carousel, the absorber and for

Pipe according to the "second embodiment";

Fig. 14A horizontal view for concentrator, rotary carousel, the absorber and for pipes according to the "second embodiment" (according to line XIVA-XIVA of Fig. 14);

Fig. 14B Vertical view of the concentrator, rotary carousel, absorber and for air pipes according to the "second embodiment" (according to line XIVB-XIVB of Fig. 14);

Fig. 15 The position of the concentrator in the morning; Fig. 15A shows the position of the concentrator at noon; Fig. 15B shows the position of the concentrator on the afternoon;

Fig. 15C shows a truss structure for mass balancing the

Concentrator is used. Mass balance is related to the torque around the shaft; Fig. 15D Positioning of the balancing mass on the concentrator in vertical section view;

Fig. 15E concentrator with balancing mass in horizontal section view; Fig. 15F drive for sun tracking after elevation;

Fig. 16 longitudinal section through absorber; Fig. 16A cross-section through absorber;

Fig. 16B top view of absorber;

Fig. 16C absorber element;

Fig. 16D alternative absorber element;

FIG. 16E depicts the concentrated solar rays in relation to the longitudinal section through the absorber; FIG.

Fig. 16 representation of the concentrated solar rays with respect to the cross section through the absorber and

Fig. 17A-H Another alternative embodiment with fixed absorber.

DETAILED DESCRIPTION OF EMBODIMENTS

According to FIG. 1, the inside of the lateral surface of a reflector 1 is frustoconical and in some way so reflective, in particular mirrored, that the incident solar rays 2 are reflected by the conical lateral surface in such a way that the reflected radiation 3 is focused in a focal zone 4. One can imagine, the inclination angle of the lateral surface to arbitrarily large so that the solar rays 2 are always focused in the focal zone 4. The basic requirement is that the sun's rays 2 run parallel to each other and fall perpendicular to the projection surface 5 of the conical lateral surface of the truncated cone.

In Fig. 1A, a segment 6 is shown as a development of the truncated cone shell as a circular ring cutout. The radius R1 and R2 come from front view. The height H of the truncated cone comes from side view of the truncated cone. In Fig. 1B, the manner of assembly in a region 7 of the individual segments 6 is shown. The circle segments 6 are arranged side by side and e.g. connected by means of a thin sheet metal tab as connecting element 8, e.g. by means of screw connection. In Fig. 1C, the top view of, from individual segments 6, composite cone, shown.

According to FIG. 2, an embodiment is shown in which a plurality of reflective surfaces 1 of reflectors 1, which are reflective on their inner side, are arranged concentrically with respect to one another and into one another such that the reflected radiation 3 always falls into a small circle, ie the focal zone 4. The conical surfaces are offset in height so that the reflected rays 3 can not or not significantly shadow. The position of the focal zone 4 can be chosen arbitrarily within certain limits and obvious to a person skilled in the art and determined by the angle of inclination 9 of the conical lateral surfaces of each truncated cone 1. A multiplicity of conical, and in particular mirrored, lateral surfaces arranged in this way produce the "concentrator" 100 which is used below as a basic concept for concentrating the solar energy.From FIGS. 2 and 2A, it can be clearly seen that the effective area of the concentrator 100 does not equal to that of FIG 2). It can be seen that the inclination angle 9 (FIG. 2) of each reflector ring (FIG. 1C) becomes ever larger toward the center. Within an inner circle 11, the concentrator remains unused. Here, sunlight can fall directly to the focal zone 4. It also shows that the required total lateral surface of the conical truncated cones is larger than the projection surface. The advantage is that you can concentrate the solar energy for any small power with the same concentration factor as in large systems. This type of concentration of solar energy requires at least two-axis solar tracking of the concentrator. In such sun tracking of the concentrator 100 is usually high temperatures in the focal zone.

In Fig. 2, a concentrator 100 is provided with the diameter of about 10 m for a specific example. Thirty circle stumps concentrically positioned one inside the other. The inner circle 11 of the concentrator is 3.33 m in diameter. The diameter of the focal zone is 282 mm. From this a concentration ratio (for concentrator of 10 m diameter) of 1146 can be determined. For this concentration ratio, a maximum theoretical temperature in the focal zone of 2247 K (1974X) can be expected (this is based on Cmax = 4621-maximum concentration ratio for the temperature of the Sun's surface Ts = 5762 K).

FIG. 2A shows the plan view of the concentrator according to FIG. 2. Here you can clearly see the projection of the reflective surfaces. According to FIG. 3 (with reference to FIG.......), The area ratios and the degree of utilization of the reflecting surfaces are shown for a specific example. The projection surface 12 of a total of 100 designated concentrator (see, inter alia, Fig. 4) is in the example 84.59 m ² . The entire reflecting surface 13 is 236.8 m ² . The projection of the reflective surface 14 is 71.56 m ² and the ratio 15 of the reflective surface to the effective area 15 is 3.31. This ratio is important in assessing the economics of the plant. It can be seen that the economy of the Investment can significantly influence by priced mirror surface. An important and meaningful quantity is the degree of utilization 16 of the projection surface; it represents the ratio of projection of the reflecting surface to the projection surface of the concentrator. According to FIG. 3, it can be seen that the degree of utilization is around 85%, which is considered to be very favorable. As a result, it is known that 85% of the circular or circular area of a concentrator can be considered as useful area.

4 shows a concentrator 100 according to the "first embodiment." The "first embodiment" is understood to mean the type of movement of the concentrator during sun tracking. In this case, the concentrator is seated on a framework truss 17 which is located at a e.g. vertical shaft 18 is supported and set by the drive 20 to azimuth in rotational movement. At the concentrator 100, forming a e.g. horizontal pivot axis Kragwellen 19 provided in bearings 21, which can sit on a support plate 22, stored and can be set by means of a drive 23 in rotational movement to elevation.

FIG. 5 shows a vertical sectional view of the concentrator 100. In the focal zone 4 of the concentrator, an absorber 24 for absorbing focused light is positioned and fixed by means of holders 25 on an outer ring 26.

For clarification, the same concentrator with focused solar beams 3 is shown in FIG.

According to Fig. 7, the outer ring 26, an inner ring 27 and these connecting radially arranged webs 28 are shown. The webs 28 have the task of carrying the reflective surfaces of the concentrator 100. The webs are connected, for example, by means of the screw connection with the outer 26 and with the inner ring 27. The on the outer ring 26 for example ange- Welded and possibly perforated plates 29 are used to attach carriers 25 which position an absorber 24 in the focal zone 4 on the side of the concentrator 100 remote from the sun. In Fig. 8, for clarity, the section AA of the concentrator (Figure 7) is shown, in Fig. 8 but also the reflectors are shown.

In Fig. 9, the support web 28 is shown for the reflectors 1. The webs 28 and the construction of the support webs 28 are usable not only for the purposes of this invention, but of independent inventive importance. On the support bar 28, in particular slit-like, recesses 28a may be provided, in which the reflectors 1 can be retracted and secured. Each slot opening has a different angle of inclination. The inclination angles of the slot openings 28a correspond to the inclination of the respective frusto-conical reflectors. The slot openings 28a can serve for the directed holding of the reflectors 1. Nevertheless, it is possible, in a particularly simple and stable manner, to use as reflectors also very thin-walled materials. Each web 28 may be fixedly connected to the reflector 1 or be. At the two ends of the web 28 openings 28 b may be provided, which serve for connecting the web 28 with the outer ring 26 and / or with the inner ring 27.

The "second embodiment" for the concentrator 100 (but without reflectors) is shown in Fig. 10. Instead of the outer ring 26, the truss segments 30, made, for example, of square tubes are provided.The truss segments 30 can be connected to each other by means of the flange connections. A lug, which serves to connect to a web 28, is welded centrally as a connecting element 30. The lattice segments 32 on which support shafts 19 are provided can be made more solid and stronger than the others because they must support the entire concentrator 100 ,

In Fig. 10 A is shown how the individual circular segments forming the reflectors 6 in a circle around, for example by means of tabs 33 and by means of the screw ben can be firmly connected and thereby form the inside reflecting truncated cone.

FIG. 11 shows the concentrator 100 and absorber 24 as well as fluid lines to dissipate the heat occurring at the absorber 24. The fluid is preferably air. The fluid is supplied to the concentrator via a stationary inlet conduit 34. Sun tracking to azimuth requires a flexible pipe joint 35 between the inlet conduit 34 and a fixed conduit 36. Accordingly, the pipes 34 and 36 are connected to each other by means of a flexible hose connection 35. The connecting tube is suitable for high temperatures (e.g., up to 1150 ° C) and is referred to as a high temperature hose. Furthermore, between the fixed pipes 36, which leads into the pivoting zone of the concentrator 100, and another fixed, approximately horizontal pipe 38, a further flexible hose connection 37 is provided for elevation because of the sun tracking. Subsequently, the fluid passes through the absorber 24, where it is heated and passed through a fixed, approximately horizontal, pipe 39, to a flexible hose connection 40 in the region of the horizontal pivot joint of the shaft 19 of the concentrator 100. From there, a fixed pipe 41 leads back down to a flexible hose connection 42 to a fixed pipe 43 through which the heat transfer fluid again leaves the concentrator.

The transport of the fluid, in particular the air flow through the fixed and flexible pipes is of independent inventive importance.

Referring to Fig. 12, an embodiment of the concentrator is shown suitable for large dimensions. For large dimensions (diameter of the concentrator of, for example, more than 30 m), the webs or support webs 28 with or as a proper carrier, such as a lattice girder must be designed. The support webs 28 with cuts as slot-like recesses 28a may be welded onto the lattice girder. Instead of truss segments 30 (FIG. 10), rings 44 and 45 are provided which are designed as a framework. In this way you can build the concentrators of considerable diameter.

13 shows a track 46 for a rotary carousel according to the "second embodiment." The track may be made of concrete or rest on foundations, eg of concrete, the fluid supply and discharge conduits 43 Air can be buried in the ground In the center of the track 46 is a foundation 47 on which a vertical shaft 18 is positioned to allow the rotary motion of the carousel.

According to FIG. 13A, rails 48 with swivels 49 are provided as the raceway 46 for rotary carousels. In the middle of the track 46 is a foundation, e.g. made of reinforced concrete, on which a vertical shaft 18 is erected for the rotational movement of the rotary carousel. The raceway with rails is intended for large concentrators (more than 30 m in diameter) and represents a low-cost solution.

In FIG. 14, the concentrator 100 according to the "second embodiment" is in front view with the rotary carousel 51, as well as the track 46, air inlet line 34, air outlet line 43 and the fixed air lines 36, 38, and 39, 41, and the absorber 24 shown.

14A shows in plan view - and FIG. 14B in side view - the rotary carousel 51, the track 46 and - in horizontal sectional view - the absorber 24 with the fluid lines, as well as the support webs 28 and the truss segments 30 in their mutual positioning.

Referring to FIG. 15, the side view and plan view rotary carousel 51 and a morning sectional view of the concentrator are shown. The orientation of the concentrator is to the east. Referring to Fig. 15A, the positioning at noon is shown, the orientation of the concentrator is to the south. According to Fig. 15.B is the Positioning in the afternoon, the concentrator's orientation is to the west.

In Fig. 15C, a truss structure 52 is shown which serves to balance the mass of the concentrator with respect to the torque about the horizontal pivot shaft. Each truss structure 52 is attached to one of the truss segments 30 of the concentrator so that its weight with the oppositely acting absorber weight, an opposite rotational torque with respect to the concentrator 19, forms. The two close to the pivot shaft and arranged on both sides of the concentrate truss structures 52 with their counterweights 52a, 52b reduce or eliminate, so - together with the concentrator weight - the torque that is caused by the absorber weight 24. The truss 52 is a carrier used to carry a counterweight. As a counterweight concrete, steel or granules with possible high density can be provided.

In Fig. 15D, the positioning of the counterweight 52a on the concentrator is shown. In the same picture, a supporting element 52d in the form of a roller and an arcuate support in the form of a rail 52d for supporting the absorber 24 during elevation tracking are shown. At the absorber 24, the roller is fastened by means of a holder 52f. It rolls over the arcuate rail and serves to support the absorber 24. The support of the absorber 24 makes a significant contribution to reducing internal stresses in the concentrator. Accordingly, the deformation of the concentrator and the focal zone 4 become smaller. The construction principle of the rotating and optionally also variable-spacing roller 52c is shown in detail in FIG. 15D.

Referring to Fig. 15E, the plan view of the concentrator with balance mass 52 is shown as a horizontal section view.

Referring to Fig. 15F, a sun tracking actuator 23 is shown after elevation. A toothed wheel 52g is connected to the shaft 19 in the sense of a pivoting drive. prevented. It is set in rotation by means of another gear and an el. Motor. The speed of the drive 52g at the output from a reducer is of the order of 1 rpm. FIG. 16 shows a longitudinal section through the absorber 24 in order to clarify its functional principle. The adsorber 24 is composed in each case of at least one adsorption element 53 in the form of an absorber plate, fluid supply tube 54, fluid removal tube 55, high-temperature window pane 56, insulation 57 of the fluid guide channels and the side walls 58 of an absorber chamber 59.

The concentrated sun rays pass through the transparent window pane 56 and fall onto the absorber plate 53. There they are converted into heat. By heat conduction through the absorber plate, the heat is given off to the air flowing past it (generally the heat transfer fluid). Air enters the fluid supply tube 54, passes ribs 53b on the sun-facing side of the absorber plate, is heated, and exits the absorber 24 through the fluid discharge tube 55. The space above the absorber plate 53 should be sealed against convective flow to prevent heat loss What could cause the cooling of the absorber plate. The high-temperature windowpane 56 serving this purpose, which may preferably be made of glass, should be suitable for high temperatures (for example, up to 1100 ° C).

In Fig. 16A, a cross section taken along the line A-A through the absorber 24 of Fig. 16 is shown

It can be seen how on the lower side of the absorber plate, the ribs 53 b are provided, which serve to transfer the heat from the absorber plate 53 to the fluid flowing between the ribs.

Referring to Fig. 16B, there is shown a horizontal sectional view taken along line CC of Fig. 16, in which the upper surface of the absorber plate is clearly seen. In Fig. 16C, a possible embodiment of the absorber plate is shown. On the upper side of the absorber plate, the cup-like elements 53a are provided on which the solar rays are incident, reflected one to two times and converted into heat. The elements 53a are preferably formed together with the ribs 53b by a casting process. The Absorbtionselement 53 may consist of refined gray cast iron by the addition of nickel. The addition of nickel is made to improve the high temperature casting property.

In Fig. 16D, another possible embodiment is shown, namely, instead of the cup 53a as shown in Fig. 16C, blind holes 60 are provided, which are cheaper to manufacture than the cups 53a. On the other side of the absorber plate, the ribs 53b are provided, so that the heat from the ribs 53b to the flowing past e.g. Air is transmitted.

For better understanding, FIG. 16E shows the longitudinal cross section through the absorber 24, in which the focused sunrays are shown schematically, while the same is shown in FIG. 16F, but for the cross section of the absorber 24.

It can be seen from FIGS. 17A to 17H that the solar energy receiving unit does not necessarily have to be guided with the mirror arrangement, ie the entire concentrator, ie it must follow the position of the sun. Rather, it is also possible for the concentrator 100 according to FIG. 17A to 17H to track the sun so that the absorber remains stationary, ie does not have to be moved. Thereby, the absorber can be directly coupled to a long-term and / or large heat storage without interposition of a heat transfer fluid or form part of it. For this purpose - as shown - the rotation and pivot point of the concentrator should be located sufficiently close to the focal zone. The invention makes it possible to concentrate solar energy at high temperature in order to keep it ready in a long-term heat storage. Provided that such a heat storage is available, this energy can be kept ready for months and used for heating throughout the winter.

Calculation example: According to the meteorological service statistics, it is known that in November the sun is about 118 h in November, 54 h in December, 78 h in January, 90 h in February, 150 h in March and 208 h in April. One of the advantages of the type of concentration of solar energy according to the invention is that even in winter the high temperatures can be achieved. Assuming that a concentrator has a thermal output of 100 kW, the example will collect 7800 kWh in January or 9000 kWh in February.

Furthermore, you can use the hot air directly to steam production, if you do not want to save the energy. Taking into account the new developments in the field of air motors (Stiriing engine), it is possible to perform the heating of the air motor in such a way that the air motor is positioned directly in focus of the concentrator so that the sun's rays fall directly on the heat exchanger surface ,

It is possible to heat the air from the waste heat of the steam turbines and e.g. To desalinate seawater. You can also use the solar energy for seawater desalination and build the green oases in the desert.

The concept of the concentrator shown has good stability properties because of the open, ie openwork reflection or mirror surfaces so that the wind flow can pass through the concentrator and thereby exerts a smaller force than flat mirrors. The use of high-temperature heat usually gives a high efficiency in energy conversion and therefore less the area for using the solar energy is required.

LIST OF REFERENCE NUMBERS

1 reflector 17 truss girder

1a lateral surfaces 18 vertical shaft (sun tracking 1b mirroring guide to azimuth)

2 sunrays 19 horizontal pivot shaft / n

(Solar tracking after Ele-

3 reflected radiation

vation)

4 focal zone

20 Drive system for tracking

5 projection surface of conical to azimuth

lateral surface

21 bearings

6 circular ring segment

22 support plate

7 composition range of Kreis¬

23 Drive system for tracking segments

after elevation

8 fasteners

24 absorbers

9 tilt angle

25 holder for absorber

10 outer circle of the concentrator

26 Outer ring of the concentrator

11 inner circle of the concentrator (support ring)

12 Projection surface 27 Inner ring of the concentrator

13 entire reflective surface (support ring)

14 projection of the reflective Flä28 bridge

28a slit-like recesses

15 ratio of mirrored Flä28b holes

to the effective area

29 Plate for the holder (25) of the

16 Degree of utilization of the projection surface absorber

che

30 truss segment Connecting element to Tra52a counterweight

web 52b granules

Truss segment 52c support element

Lug 52d support

Piping 52e ball bearings

High temperature hose 52f mounts

Piping 52g gear

High temperature hose 53 Absorbtionselement

Pipe 53a cup-shaped elements piping 53b ribs

High temperature hose 54 fluid supply pipe

Pipeline 55 fluid discharge tube

High temperature hose 56 window pane

Pipeline 57 insulation

Ring 58 insulation

Ring 59 absorber room

Runway for carousel 60 holes

Foundation for the vertical 100 concentrator

wave

AK outer circle

rails

IK inner circle

swell

H reflector width

Foundation for the shaft Z central area

Rotary carousel R Sun-facing area Truss structure

Claims

The total solar station nachführbarer concentrator for concentrating solar energy radiation in a focal zone (4) by means of fixedly oriented reflectors (1),

characterized,

in that, for the reflection of the solar rays by means of the reflectors (1), a plurality of reflective lateral surfaces (1a) are arranged in at least approximately the shape of truncated cones or segments of truncated cones of different inclinations at least partially in one another and concentric with one another such that the solar rays after the reflection on a much smaller area, namely on the focal zone (4) are focused.

Concentrator according to claim 1, characterized in that the focal zone (4) is located on the side of the concentrator (100) remote from the sun.

Concentrator according to claim 1 or 2, characterized in that the reflectors (1) consist of strips which are flat in cross-section and of a material suitable as a carrier layer, which forms or carries the lateral surface (1a) reflecting the sunlight at least on one side.

Concentrator according to one of claims 1 to 3, characterized in that the approximate shape of truncated cones are formed by circular ring segments (6) in such a way that first plane circular ring segments (6) in the circle or in the circular arc section next to each other and each under an inclination angle of the inclination the corresponding lateral surface (1a) corresponds to the respective truncated cone, are arranged so that all or almost all incident sunbeams are focused on a small area. Concentrator according to one of claims 1 to 4, characterized in that the widths (H) of the individual reflectors (1) is equal to or smaller than the diameter of the focal zone (4) of the concentrator or of the corresponding truncated cone.

Concentrator according to one of claims 1 to 5, characterized in that a sun-facing mirroring (1b) of the lateral surfaces (1a) of the truncated cones by applying a mirror foil, by polishing the lateral surface (1a), or by a coating of the lateral surface (1a) by means of a nanostructure or by application of silver nitrate.

Concentrator according to one of claims 1 to 6, characterized in that the reflectors (1) between an outer ring (26) or ring portion and an inner ring (27) or ring portion are arranged in a staggered arrangement so that the reflected sun rays not or only can be slightly shadowed by the / the adjacent reflectors (1).

Concentrator according to the preamble of claim 1, in particular according to one of claims 1 to 7, characterized in that the reflectors (1) are supported by webs (28) forming spoke or rib elements.

Concentrator according to claim 8, characterized in that the reflectors in slot-like, on the webs (28) provided recesses (28a) can be inserted, so that the lateral surfaces (1a) of the truncated cones under the different angles of inclination (9) are positioned.

Concentrator according to claim 8 or 9, characterized in that the supporting webs (28) are fixedly connected to an outer frame or an outer ring (26) and an inner frame or inner ring (27).

11. A concentrator according to any one of claims 1 to 10, characterized in that for sun tracking of the concentrator after elevation an outer frame or an outer ring (26) is provided which has at least one horizontal pivot bearing or pivot shaft (19).

12. A concentrator according to any one of claims 1 to 1 1, characterized in that at least one of the reflectors supporting outer frame or outer ring (26) forms a framework or composed of truss segments (30) is set.

13. Concentrator according to the preamble of claim 1, in particular according to one of claims 1 to 12, characterized in that an absorber (24) is provided which converts the concentrated in the focal zone (4) solar radiation into heat, and that the absorber (24) is cooled via a flow channel by means of a heat transfer fluid, such as air.

Concentrator according to claim 13, characterized in that pipes (34, 36, 38, 39, 41, 43) for heat dissipation from the absorber (24) by means of flexible, suitable for high temperatures hose connections, (35, 37, 40, 42) are such that the concentrator (100) in rotation after azimuth and after elevation is pivotal. 15. Concentrator according to one of claims 1 to 14 with the reflectors (1) bearing storage or rib elements, characterized in that the storage or rib elements are designed as trusses or include trusses. 16. Concentrator according to one of claims 1 to 15, characterized in that for sun tracking azimuth a carrying rotary carousel (51) is provided that the horizontal rotational movement by means of a circular track (46) executes.

17. A concentrator according to any one of claims 1 to 16, characterized in that for mass balance based on the torques resulting from weights of the concentrator (100) and any absorber (24), at least one counterweight (52 a) is provided.

18. Concentrator according to one of claims 1 to 17, characterized in that for the conversion of the concentrated solar radiation (3) into heat in the focal zone (4), an absorption element (53) is provided which on its side facing the sun with a its surface enlarging contour is provided and has on the opposite side longitudinal ribs (53b) for heat transfer to a flowing past heat fluid.

19. A concentrator according to claim 18, characterized in that the Absorbtionselement (53) made of gray cast iron, silicon carbide, heat-resistant steel, stainless steel, or at least comprises one of these materials.

20. A concentrator according to any one of claims 1 to 19 with an absorber (24) which converts the focused in the focal zone (4) solar radiation into heat, characterized in that the absorber (24) by means of a window pane (56), in particular made of heat-resistant glass , is covered.

Method for concentrating solar energy radiation in a focal zone (4) by means of a reflector (1), which can be tracked in total to the position of the sun as a whole

characterized,

that for reflection of the sun's rays by means of the reflectors (1) a plurality of reflective lateral surfaces (1a) in at least approximately the Shape of truncated cones or segments of truncated cones of different inclinations at least partially into each other and concentric with each other are arranged so that the sun's rays are focused due to the reflection on a much smaller area, namely on the focal zone (4).