Heat exchange enhancement

• US 7,800,898 B2
• Filed: 03/28/2008
• Issued: 09/21/2010
• Est. Priority Date: 03/31/2006
• Status: Expired due to Fees

• Current Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Original Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Inventors: Shuy, Geoffrey Wen-Tai
• Primary Examiner(s): HOFFBERG, ROBERT JOSEPH
• Application Number:
  US12/057,811
• Publication Number:
  US 20090084530A1
• Time in Patent Office: 907 Days
• Field of Search: 361/690, 361/692, 361694-695, 361697-700, 361/704, 361/717, 165 802- 805, 165/104.33, 165/185, 174/15.2, 174/16.1, 174/16.3, 362/218, 362/294, 362/373, 362/547
• US Class Current: 361/679.47
• CPC Class Codes: F21K 9/20 Light sources comprising attachment means
• CPC Class Codes: F21V 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/677 the fans being used for discharging
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/83 the elements having apertures, ducts or channels, e.g. heat radiation holes
• CPC Class Codes: F21V 29/89 Metals
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: F28D 15/0233 the conduits having a particular shape, e.g. non-circular cross-section, annular F28D15/0241, F28D15/0266 take precedence
• CPC Class Codes: F28D 15/0275 Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 7/20009 using a gaseous coolant in electronic enclosures in cabinets of standardized dimensions H05K7/20536; in server cabinets H05K7/20709; in vehicle electronic casings H05K7/20845; in power control electronics H05K7/2089; in displays H05K7/20954
• CPC Class Codes: H05K 7/20154 Heat dissipaters coupled to components

Abstract

A heat exchange structure includes a plurality of elongated air ducts. The heat exchange structure has an exterior heat exchange surface and interior heat exchange surfaces, the interior surfaces being in the elongated air ducts. The heat exchange structure includes a plurality of heat generators that are distributed on the exterior heat exchange surface along an elongated direction of the air ducts, in which air flowing in the air duct is heated successively by heat from the heat generators, and air flow in the air duct is enhanced by buoyancy of heated air.

Claims

1. A method comprising:

transferring thermal energy from a plurality of heat generators to multiple locations of an interior heat exchange surface of a heat exchange structure, the interior heat exchange surface being in an air duct of the heat exchange structure, the heat generators being coupled to an exterior heat exchange surface of the heat exchange structure and disposed along an elongated direction of the air duct; and

heating air in the air duct successively by transferring thermal energy from the multiple locations of the interior heat exchange surface to the air as the air flows through the air duct, enhancing air flow in the air duct by buoyancy of heated air;

wherein heating the air in the air duct further comprises;

transferring thermal energy from the multiple locations of the interior heat exchange surface to an air-impermeable first surface of a thin layer of ceramic material formed on the heat exchange structure;

transferring thermal energy through the thin layer of ceramic material from the air-impermeable first surface of the thin layer of ceramic material to a porous second surface of the thin layer of ceramic material;

heating air molecules trapped in pores of the porous second surface of the thin layer of ceramic material; and

transferring thermal energy from the thin layer of ceramic material to air in the air duct by moving the air molecules from the pores of the porous second surface of the thin layer of ceramic material to the air flowing in the air duct.

2. The method of claim 1 wherein transferring thermal energy from the heat generators to the interior heat exchange surface comprises transferring thermal energy through a wall separating the exterior heat exchange surface and the interior heat exchange surface, the wall having a thickness less than 5 mm.

3. The method of claim 1 wherein transferring heat from the heat generators to the multiple locations comprises transferring heat from electronic devices to the multiple locations.

4. A method comprising:

transferring thermal energy from a heat generator to a heat pipe;

transferring thermal energy from different portions of the heat pipe to a heat exchange structure that comprises a plurality of elongated air ducts, the different portions of the heat pipe aligned along an elongated direction of the air ducts; and

heating the air in the air ducts successively by transferring thermal energy from the different portions of the heat pipe to the air flowing in the air ducts, enhancing air flow in the air ducts by buoyancy of heated air;

wherein heating the air in the air ducts further comprises;

transferring thermal energy from the heat pipe to an air-impermeable first surface of a thin layer of ceramic material formed on the heat exchange structure;

transferring thermal energy through the thin layer of ceramic material from the air-impermeable first surface of the thin layer of ceramic material to a porous second surface of the thin layer of ceramic material;

heating air molecules trapped in pores of the porous second surface of the thin layer of ceramic material; and

transferring thermal energy from the thin layer of ceramic material to air in the air ducts by moving the air molecules from the pores of the porous second surface of the thin layer of ceramic material to the air flowing in the air ducts.

5. A method comprising:

mounting an array of heat generators on an exterior heat exchange surface of a heat exchange structure, the heat exchange structure comprising elongated air ducts, the array of heat generators comprising groups of heat generators, each group having heat generators mounted along an elongated direction of the air ducts,

the heat exchange structure comprising interior heat exchange surfaces being in the elongated air ducts, the interior heat exchange surfaces configured to successively heat air in the air ducts by transferring heat from the array of heat generators to the air flowing in the air ducts and enhancing air flow in the air ducts due to buoyancy of heated air;

coating the interior heat exchange surfaces in the elongated air ducts with a thin layer of ceramic material;

wherein coating the interior heat exchange surfaces further comprises initially coating the interior heat exchange surfaces with a first sub-layer and finally coating the interior heat exchange surfaces with a second sub-layer;

wherein the thin layer of ceramic material is configured to be air impermeable at a first surface of the first sub-layer which attaches to the interior heat exchange surfaces, and porous at a second surface of the second sub-layer, the second surface being opposed to the first surface and exposed to the air flow in the air ducts.

6. The method of claim 5 in which mounting the array of heat generators comprises mounting an array of light sources.