Heat exchanger for an electronic heat pump

• US 6,446,442 B1
• Filed: 07/31/2001
• Issued: 09/10/2002
• Est. Priority Date: 10/07/1999
• Status: Expired due to Fees

• Current Assignee: Hydrocool Pty Limited
• Original Assignee: Hydrocool Pty Limited
• Inventors: McDonald, David, Banney, Ben, Chandratilleke, Tilak T., Batchelor, Andrew W.
• Primary Examiner(s): Doerrler, William C.
• Assistant Examiner(s): SHULMAN, MARK S
• Application Number:
  US09/857,668
• Time in Patent Office: 406 Days
• Field of Search: 62/33, 62/32, 622/592
• US Class Current: 62/3.3
• CPC Class Codes: F25B 21/02 using Peltier effect; using Nernst-Ettinghausen effect
• CPC Class Codes: F25B 25/00 Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
• CPC Class Codes: F25B 2500/01 Geometry problems, e.g. for reducing size

Abstract

A heat exchanger 17 for an electronic heat pump 11 includes a thermally conductive base plate 18 having first and second surfaces, the first surface being flat and adapted to make intimate surface contact with a surface of the electronic heat pump and the second surface being obverse to the first surface and supporting an array of thermally conductive fins 21. The adjacent fins 21 define there between a plurality of micro channels.

Claims

1. A heat exchanger for an electronic refrigerating heat pump that has a hot side and a cold side, the heat exchanger comprising:

a thermally conductive base having a first surface and a second surface, the second surface being obverse to the first surface;

a thermally conductive cover spaced apart from the base;

a plurality of thermally conductive walls between the base and the cover;

a plurality of closed narrow channels defined between adjacent walls, the base, and the cover through which a heat transfer liquid flows when the heat exchanger is in use;

wherein each narrow channel further comprises;

an inlet end of each narrow channel;

an outlet end of each narrow channel;

a width W of each narrow channel;

a height H of each narrow channel;

wherein the width W of each narrow channel is between about 0.1 mm and about 1.0 mm and the ratio of channel height H to channel width W is between about 4;

1 to about 15;

1; and

wherein the flow of the heat transfer liquid through the heat exchanger only occurs through the closed narrow channels from the inlet end to the outlet end.

2. The heat exchanger of claim 1, further comprising:

a liquid inlet to the heat exchanger in communication with the inlet end of each narrow channel; and

a liquid outlet from the heat exchanger in communication with the outlet end of each narrow channel.

3. The heat exchanger of claim 1, wherein each closed narrow channel further comprises:

a portion of the second surface of the base; and

a portion of the cover disposed over a top of the adjacent walls.

4. The heat exchanger of claim 1, further comprising a manifold, the manifold comprising:

flat plate, two side walls, and two end walls defining an enclosure for receiving the heat exchanger;

an inlet port for receiving a liquid;

an inlet channel extending substantially perpendicular to the narrow channels from the inlet port to at least a furthest narrow channel from the inlet port to evenly distribute a flow of the liquid between the plurality of narrow channels;

an outlet port for discharging the liquid, the outlet port being located at a diagonal opposite end of the manifold from the inlet port;

an outlet channel extending substantially perpendicular to the narrow channels from the outlet port to at least a furthest narrow channel from the outlet port to allow an even distribution a flow of the liquid from between the plurality of narrow channels; and

wherein the fluid input and output channels are parallel and defining there between a central cavity for situating the plurality of walls and narrow channels.

5. The heat exchanger of claim 4, wherein the flat plate of the manifold comprises the cover, the side walls of the manifold comprise outer side walls of the outer most narrow channels, and the end walls of the manifold comprise end walls of the inlet and outlet channels.

6. The heat exchanger of claim 4, wherein the cover further comprises a resilient polymeric sheet interposed between the manifold and the heat exchanger walls.

7. The heat exchanger of claim 4, wherein the base is in a sealing relationship with the central cavity.

8. The heat exchanger according to claim 1, wherein the walls are integral with the base and further comprising end walls that are constituted by a portion of the base.

9. The heat exchanger according to claim 1, wherein the walls are soldered to the base and further comprising end walls that are constituted by a portion of the base.

10. The heat exchanger according to claim 1, wherein the walls are formed by folding a continuous piece of thermally conductive material.

11. The heat exchanger according to claim 10, wherein the walls are soldered to the base and to the cover overlying the folded piece of thermally conductive material.

12. The heat exchanger according to claim 1, wherein the walls are integral with the cover and further comprising end walls that are constituted by a portion of the cover.

13. The heat exchanger according to claim 1, wherein the walls are soldered to the cover and further comprising end walls that are constituted by a portion of the cover.

14. The heat exchanger according to claim 1, wherein the height H of each closed narrow channel is less than about 10 mm.

15. The heat exchanger according to claim 1, wherein the base and cover are in a parallel and spaced apart relationship, wherein the plurality of thermally conductive walls are formed by a continuous piece of folded corrugated metal member disposed between the base and the cover, the folded corrugated metal member comprising top ends, bottom ends, and tapered sidewalls defining the plurality of closed narrow channels, wherein the top ends are attached to the cover and the bottom ends are attached to the base to form the closed narrow channels.

17. The hear exchanger according to claim 1, wherein the plurality of thermally conductive walls further comprise tapered side walls formed from a folded sheet of metal defining alternating narrow channels, wherein e direction of the side wall taper of each narrow channel is opposite to that of the immediately adjacent narrow channels.

16. A heat exchanger for use with a heat exchanger module comprising one or more heat exchangers and an electronic heat pump in combination, each heat exchanger comprising:

a thermally conductive base having a first surface and a second surface;

a thermally conductive cover spaced apart from the base;

the first surface being substantially flat and adapted to make intimate surface contact with a surface of the electronic heat pump; and

the second surface being obverse to the first surface and supporting an array of thermally conductive walls, adjacent walls defining there between a plurality of closed micro-channels between the base and the cover;

wherein a flow of a heat transfer liquid only occurs through the micro-channels;

wherein dimensions of the micro-channels, comprising a height H and a width W, are optimized so that flow exists predominately in the developing region as the liquid flows through the micro-channels;

an aspect ratio defined by the height H to width W of the micro-channels, the aspect ratio being between about 4;

1 and about 15;

1;

wherein the thermal resistance of the micro-channels is reduced to about 0.03°

C./W by;

providing thermally conductive materials to spread heat flux evenly around the micro-channel walls that are in contact with the liquid to increase the effective area of heat transfer between the heat exchanger and the liquid; and

providing narrow micro-channels to increase the aspect ratio to affect the flow characteristics of the liquid flowing through the micro-channels to further increase heat transfer between the heat exchanger and the liquid.