HELIOSTAT AND SYSTEM

• US 20100175738A1
• Filed: 04/15/2008
• Published: 07/15/2010
• Est. Priority Date: 04/15/2007
• Status: Active Grant

• Current Assignee: BrightSource Industries (Israel) Ltd (BrightSource Energy)
• Original Assignee: BrightSource Industries (Israel) Ltd (BrightSource Energy)
• Inventors: Kroizer, Israel, Franck, Danny, Gilon, Yoel, Walzer, Susan, Huss, Hagai, Huss, Shmuel
• Granted Patent: US 8,063,349 B2
• Time in Patent Office: Days
• US Class Current: 136/246
• CPC Class Codes: F24S 20/20 Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
• CPC Class Codes: F24S 2023/87 Reflectors layout
• CPC Class Codes: F24S 23/70 with reflectors
• CPC Class Codes: F24S 30/452 Vertical primary axis
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 10/47 Mountings or tracking

Abstract

A solar heliostat and system are described with various characteristics particularly suitable for concentrating systems with a relatively large number of small heliostats. Other features contribute to high performance, low cost, high durability, and high temperature operation, such as desired for high efficiency thermal power generation.

Claims

1. A heliostat, comprising:

a float glass mirror having a thickness of 3 to 5 mm and an edge therearound; and

a hollow back of sheet metal with a skirt defining a dish shape and standoffs positioned to contact the mirror and having heights to determine a shape of the mirror;

the hollow back having a skirt portion that covers the edge;

the mirror edge being sealed to the skirt portion;

the hollow back being impermeable such as to enclose a back of the glass mirror and to protect it from exposure to ambient gases;

the standoffs being adhesively bonded to the mirror in such a manner that the mirror and the hollow back cooperatively form a truss in which they act as compression and tension members to contribute substantially to the rigidity of the combination of the hollow back and the mirror.

2. The heliostat of claim 1, further comprising a material between the standoffs and the mirror to provide allowance for differential expansion of the glass and the hollow back.

3. The heliostat of claim 1, wherein the standoffs include at least one frustoconical portion.

4. The heliostat of claim 1, wherein the mirror is curved to define a focal spot at a distance of at least 20 meters.

5. The heliostat of claim 1, wherein at least one of the standoffs is a channel shaped portion.

6. A heliostat, comprising:

a float glass mirror; and

a hollow back of sheet metal with a wall portion substantially opposite the mirror;

the hollow back having a skirt portion that covers an edge of the float glass mirror;

said mirror edge being sealed to the skirt portion;

the hollow back being impermeable such as to enclose a back of the glass mirror and to protect it from exposure to ambient gases.

7. The heliostat of claim 6, wherein the glass mirror has a thickness of 3 to 5 mm.

8. The heliostat of claim 6, wherein the skirt portion of the hollow back defines a dish shape.

9. The heliostat of claim 6, wherein the hollow back has standoffs positioned to contact the mirror, and the standoffs have heights which determine a shape of the mirror.

10. The heliostat of claim 9, wherein the standoffs are adhesively bonded to the mirror in such a manner that the mirror and the hollow back cooperatively form a truss in which they act as compression and tension members to contribute substantially to the rigidity of the combination of the hollow back and the mirror.

11. The heliostat of claim 10, further comprising a material between the standoffs and the mirror to provide allowance for differential expansion of the glass and the hollow back.

12. The heliostat of claim 9, further comprising a material between the standoffs and the mirror to provide allowance for differential expansion of the glass and the hollow back.

13. The heliostat of claim 9, wherein the standoffs include at least one frustoconical portion.

14. The heliostat of claim 6, wherein the mirror is curved to define a focal spot at a distance of at least 20 meters.

15. The heliostat of claim 6, wherein at least one of the standoffs is a channel shaped portion.

16. A solar concentrating system, comprising:

a plurality of heliostats;

at least one controller configured to control the heliostats such that they are generally aimed at respective aiming points of a receiver and track the apparent movement of the sun;

the controller being further configured to randomize the aiming points to achieve a statistically constant distribution of flux over a predefined area of the receiver.