Cooling system for LED device

• US 9,356,214 B2
• Filed: 06/18/2013
• Issued: 05/31/2016
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Musser, Jordon, Stratas, Chris
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Fallahkhair, Arman B
• Application Number:
  US13/921,067
• Publication Number:
  US 20140003068A1
• Time in Patent Office: 1,078 Days
• Field of Search: 362/373, 362/294, 362/547, 362/249.02, 362/101, 362/382, 362/249.01, 362/264, 16510421-10424, 165/104.33, 165/65, 165/66
• US Class Current: 1/1
• CPC Class Codes: F21K 9/20 Light sources comprising attachment means
• CPC Class Codes: F21S 8/04 intended only for mounting on a ceiling or the like overhead structures F21S8/02 takes precedence; details of ceiling bases F21V21/03
• CPC Class Codes: F21V 17/12 by screwing
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/71 using a combination of separate elements interconnected by heat-conducting means, e.g. with heat pipes or thermally conductive bars between separate heat-sink elements
• CPC Class Codes: F21V 29/89 Metals
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

A lighting assembly includes a cooling system configured to enable the dissipation of a large amount of energy in the form of heat generated by a light source. Heat is dissipated without heating surrounding components, such as the one or more power supply units and device electronics. The cooling system is configured as a gravity feed system that does not require a powered fluid pump. In some embodiments, the cooling loop is configured as a thermal siphon that uses a boiling fluid to transport heat between the evaporator and the radiators. In some embodiments, the evaporator also functions as a device chassis, which reduces the overall part count. In some embodiments, the light source is a plurality of LEDs.

Claims

1. A lighting assembly for cooling a light source, the lighting assembly comprising:

a. a light source;

b. an evaporator thermally coupled to at least a portion of the light source, wherein the evaporator comprises a reservoir having a walled structure for containing a fluid within the reservoir, wherein the walled structure comprises an upper spherical portion that forms a ceiling wall of the reservoir, the evaporator is configured such that at least a portion of the fluid is vaporized by heat transferred from the light source; and

c. one or more cooling loops coupled to the evaporator, wherein each cooling loop comprises a transfer pipe coupled to the evaporator, a radiator coupled to the transfer pipe, and a return pipe coupled to the radiator and to the evaporator, further wherein the radiator is configured to receive vapor from the evaporator via the transfer pipe and to condense the vapor, and the radiator and the return pipe are configured to gravity feed the fluid to the evaporator.

2. The lighting assembly of claim 1 wherein the radiator includes a first end coupled to the transfer pipe and a second end, and the radiator is aligned along a non-horizontal plane with the first end positioned higher than the second end.

3. The lighting assembly of claim 2 wherein the return pipe includes a first end coupled to the second end of the radiator and a second end coupled to the evaporator, the return pipe is configured and aligned having the first end of the return pipe positioned higher than the second end of the return pipe.

4. The lighting assembly of claim 2 further comprising a plurality of transfer pipes coupled to the evaporator and a plurality of radiators coupled to the plurality of transfer pipes, wherein each radiator includes the first end and the second end and at least one of the plurality of transfer pipes is coupled to the first end of one of the plurality of radiators.

5. The lighting assembly of claim 1 wherein the transfer pipe comprises a first portion coupled to the evaporator and aligned substantially vertically from the evaporator and a second portion angled from the first portion and coupled to the radiator.

6. The lighting assembly of claim 5 wherein the second portion is angled at 30 to 60 degrees with respect to the first portion.

7. The lighting assembly of claim 1 wherein the radiator comprises a finned radiator.

8. The lighting assembly of claim 7 wherein the evaporator and the fluid mixture are configured such that when the portion of the fluid is vaporized by heat transferred from the light source a boiling fluid is formed, further wherein the evaporator and the transfer pipe are configured such that the boiling fluid is siphoned from the evaporator to the radiator.

9. The lighting assembly of claim 1 wherein the transfer pipe comprises a finned pipe.

10. The lighting assembly of claim 1 wherein the fluid comprises a fluid mixture having at least a first fluid and a second fluid having a higher boiling temperature than the first fluid, wherein the first fluid comprises the portion of the fluid vaporized by heat transferred from the light source.

11. The lighting assembly of claim 1 wherein the light source comprises a plurality of light emitting diodes.

12. The lighting assembly of claim 1 wherein the plurality of light emitting diodes generate greater than or equal to 100W.

13. The lighting assembly of claim 1 further comprising a plurality of transfer pipes and a plurality of return pipes coupled to the evaporator, a plurality of radiators wherein each radiator includes a first end and a second end, an input fluid header commonly coupled to the first end of each radiator, and an output fluid header commonly coupled to the second end of each radiator, further wherein each transfer pipe is coupled to the input fluid header and each return pipe is coupled to the output fluid header.

14. The lighting assembly of claim 1 wherein the evaporator is a single chamber formed by the walled structure.

15. A lighting assembly for cooling a light source, the lighting assembly comprising:

a. a light source;

b. an evaporator thermally coupled to at least a portion of the light source, wherein the evaporator comprises a reservoir having a walled structure for containing a fluid within the reservoir, wherein the walled structure comprises an upper spherical portion that forms a ceiling wall of the reservoir, the evaporator is configured such that at least a portion of the fluid is vaporized by heat transferred from the light source;

c. a transfer pipe coupled to the evaporator such that vapor formed in the evaporator rises through the transfer pipe;

d. a radiator coupled to the transfer pipe, wherein the radiator includes a first end coupled to the transfer pipe and a second end, and the radiator is aligned along a non-horizontal plane with the first end positioned higher than the second end, further wherein the radiator is configured such that vapor received from the transfer pipe is condensed to fluid and the fluid is gravity fed to the second end; and

e. a return pipe coupled to the radiator, wherein the return pipe includes a first end coupled to the second end of the radiator and a second end coupled to the evaporator, the return pipe is configured and aligned having the first end of the return pipe positioned higher than the second end of the return pipe such that fluid output from the second end of the radiator is gravity fed to the evaporator.

16. The lighting assembly of claim 15 wherein the transfer pipe comprises a first portion coupled to the evaporator and aligned substantially vertically from the evaporator and a second portion angled from the first portion and coupled to the radiator.

17. The lighting assembly of claim 16 wherein the second portion is angled at 30 to 60 degrees with respect to the first portion.

18. The lighting assembly of claim 15 wherein the fluid comprises a fluid mixture having at least a first fluid and a second fluid having a higher boiling temperature than the first fluid, wherein the first fluid comprises the portion of the fluid vaporized by heat transferred from the light source.

19. The lighting assembly of claim 18 wherein the evaporator and the fluid mixture are configured such that when the portion of the fluid is vaporized by heat transferred from the light source a boiling fluid is formed, further wherein the evaporator and the transfer pipe are configured such that the boiling fluid is siphoned from the evaporator to the radiator.

20. The lighting assembly of claim 15 further comprising a plurality of transfer pipes coupled to the evaporator and a plurality of radiators coupled to the plurality of transfer pipes, wherein each radiator includes the first end and the second end and at least one of the plurality of transfer pipes is coupled to the first end of one of the plurality of radiators.

21. The lighting assembly of claim 15 wherein the radiator comprises a finned radiator.

22. The lighting assembly of claim 15 wherein the transfer pipe comprises a finned pipe.

23. The lighting assembly of claim 15 wherein the light source comprises a plurality of light emitting diodes.

24. The lighting assembly of claim 15 wherein the plurality of light emitting diodes generate greater than or equal to 100W.

25. The lighting assembly of claim 15 further comprising a plurality of transfer pipes and a plurality of return pipes coupled to the evaporator, a plurality of radiators wherein each radiator includes a first end and a second end, an input fluid header commonly coupled to the first end of each radiator, and an output fluid header commonly coupled to the second end of each radiator, further wherein each transfer pipe is coupled to the input fluid header and each return pipe is coupled to the output fluid header.

26. The lighting assembly of claim 15 wherein the evaporator is a single chamber formed by the walled structure.