PARABOLIC COLLECTOR

• US 20120266868A1
• Filed: 12/16/2010
• Published: 10/25/2012
• Est. Priority Date: 12/17/2009
• Status: Active Grant

• Current Assignee: Airlight Energy IP SA
• Original Assignee: Airlight Energy IP SA
• Inventors: Pedretti, Mauro
• Granted Patent: US 9,146,043 B2
• Time in Patent Office: Days
• US Class Current: 126/684
• CPC Class Codes: F24S 23/715 flexible
• CPC Class Codes: F24S 23/81 flexible F24S23/715, F24S23/745 take precedence
• CPC Class Codes: F24S 25/13 Profile arrangements, e.g. trusses F24S25/12 takes precedence
• CPC Class Codes: F24S 30/425 Horizontal axis
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 10/47 Mountings or tracking
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A parabolic collector for the concentration of solar radiation has a reflective surface which is approximated to an ideal paraboloid and has a number of individual collectors. According to the invention, individual collectors are provided with a pressure cell with a concentrator formed from a flexible film, whereby, under operating pressure conditions, the concentrator is curved differently in a predetermined manner in a first and in a second direction for approximating the ideal paraboloid, such that the radius of curvature in the first direction is greater than that in the second direction. The production method for such a concentrator consists in the fact that the outline of the individual collectors is designed in the outline of the parabolic collector, the true dimensions of the individual collectors being determined from the intersection of cylinders positioned on the outline with the paraboloid of the parabolic collector.

Claims

1. A parabolic collector for concentration of solar radiation, comprising:

a reflecting surface that approximates an ideal paraboloid;

a plurality of individual collectors;

wherein the plurality of individual collectors have a concentrator made from a flexible film which, in operation, can be loaded with pressure;

wherein the concentrator, under operating pressure conditions, is curved differently in a predetermined manner in a first and in a second direction over its corresponding extent in each case for approximating the ideal paraboloid; and

wherein a curvature in the first direction is more pronounced than a curvature in the second direction.

2. The parabolic collector according to claim 1, wherein the plurality of individual collectors have a concentrator with elliptical circumference, a major axis of which lies in a plane passing through an axis of symmetry of the collector and wherein the first and second directions run perpendicularly to one another.

3. The parabolic collector according to claim 2, wherein a minor axis of the concentrator lies in a plane running perpendicularly to the axis of symmetry of the collector.

4. The parabolic collector according to claim 1, wherein an elliptically constructed edge of the concentrator of the plurality of individual collectors lies essentially on a surface of the collector corresponding to an ideal paraboloid.

5. The parabolic collector according to claim 1, wherein the plurality of individual collectors are provided as collectors with a pressure cell in which the concentrator is preferably stretched and which divides the pressure cell into two zones, between which a pressure difference prevails under operating pressure conditions, by means of which pressure difference the concentrator is loaded in a serviceable manner.

6. The parabolic collector according to claim 1, wherein individual collectors are provided as collectors with a vacuum cell in which the concentrator is preferably stretched and, under operating pressure conditions, is subjected to a pressure difference by means of the external pressure, by means of which pressure difference it is loaded in a serviceable manner.

7. The parabolic collector according to claim 1, wherein in the same, a first group of individual collectors are arranged with similar spacing from one another, preferably adjoining one another, and each with the same spacing from an origin of the ideal paraboloid, and at least one further group of individual collectors is provided with the same spacing to one another and the same spacing to the origin, the individual collectors of which group piece by piece protrude into one of the intermediate spaces, formed by means of adjacent individual collectors of the first group, in such a manner that the collector is densely occupied with individual collectors.

8. The parabolic collector according to claim 7, comprising a further group of individual collectors, which essentially occupies the intermediate spaces of another group of individual collectors in such a manner that the collector is densely occupied with individual collectors.

9. The parabolic collector according to claim 1, wherein the plurality of individual collectors are integrated into a carrier structure made from concrete.

10. The parabolic collector according to claim 9, wherein the carrier structure covers the plurality of individual collectors outwardly, preferably in such a manner that, as a result, a vacuum cell for the plurality of individual collectors is formed.

14. A method for a production of a parabolic collector according to claim 1, wherein in an outline of a collector orientated perpendicularly to its outline plane, the plurality of individual collectors of the collector are arranged via their outline circles and therefrom, true dimensions of the individual collectors are determined from an intersection which results in penetration of a cylinder standing on the respective outline circle with the ideal paraboloid of the collector.

15. The method according to claim 14, wherein in the outline, centre points of the outline circles of the plurality of individual collectors are arranged in nodes of a grid which is laid in the outline of the collector, and wherein the grid and a radii of the outline circles are determined in such a manner that an area percentage of the outline circles is maximised on the surface of the outline.

16. The method according to claim 15, wherein the grid is formed from equilateral triangles, wherein a node lies at the origin of the paraboloid and the radii of the outline circles are selected in such a manner that the individual collectors arranged in the collector adjoin one another.

17. The method according to claim 14, wherein a ratio of focal length to diameter is determined to 1 and is preferably less than 1, particularly preferably in the range of 0.75 to 0.4, especially equal to 0.5.

11. An individual collector for a parabolic collector of a solar power plant which has a concentrator formed from a flexible film, which concentrator is for its part loaded in operation by means of pressure and under operating pressure conditions reflects solar radiation to an absorber element;

wherein the concentrator is, under operating pressure conditions, curved in a predetermined manner in each case over its corresponding extent in a first direction, such that reflected solar radiation is reflected by means of this curvature into a focal line region;

wherein, in a second direction, the concentrator is likewise, but differently curved, such that due to this curvature, a focal line region of this section is at least shortened.

12. The individual collector according to claim 11, wherein the concentrator, in the second direction, is curved in such a manner that the focal line region shortens to a focal point region and wherein the concentrator is elliptically stretched.

13. The individual collector according to claim 11, wherein the concentrator consists of an orthotropic film with an e-modulus which is different in different directions, and wherein the concentrator is orientated and stretched in such a manner that a direction with a higher e-modulus lies parallel to a direction of its longer extent.

18. A method for production of an individual collector according to claim 11, which has a concentrator with an orthotropic film, the e-modulus of which is higher in one direction than in another direction running essentially transversely to this one, and wherein the orthotropic film is orientated in the individual collector in such a manner that the direction with the higher e-modulus coincides with the direction of the largest spacing of the concentrator, in the case of an elliptical construction with the major axis of the stretched concentrator.