Heat Exchanger With Angled Fin
An angled finned heat exchanger and associated method is provided. The heat exchanger cools the air provided to the electronic components and is disposed at an angle with respect to direction of air flow. The heat exchanger comprises a plurality of fins that are at an angle with respect to frontal area of the heat exchanger. In alternate embodiments, the angle of the fin is optimized to minimize air pressure loss and/or drop. Some suggested methods of fabrication of the fins are also provided.
1. Field of the Invention
This invention relates to cooling of electronic packages used in computing system environments and more particularly to cooling of electronic components used in large computing environments such as those including servers.
2. Description of Background
The industry trend has been to continuously increase the number of electronic components inside computing system environments. A computing system environment can simply comprise a single personal computer or a complex network of large computers in processing communication with one another. Increasing the components inside a simple computing system environment does create a few problems, but such an increase in complex computing system environments that include large computer complexes lead to many challenges. This is because in large and complex environments, any simple problem is magnified so that seemingly isolated issues start to affect one another, and have to be resolved in consideration with one another.
One such particular challenge when designing any computing system environment is the issue of heat dissipation. Heat dissipation poses a challenge at both the module and system level. Increased air flow rates are needed to effectively cool modules and to limit the temperature of the air that is exhausted into the computing environment and ultimately the data center level. Prior art continues to struggle to achieve an acceptable solution for the heat dissipation problem.
One such concept was presented in U.S. Pat. No. 6,775,137. In that patent an air and liquid heat removal enclosure system was provided with an enclosure scheme within which a stack(s) of electronic drawers was packaged. Air was then circulated within the enclosure to cool the electronics and was ultimately passed across one or more air-to-liquid finned-tube heat exchanger(s). The heat exchangers were mounted to the side of the electronics frame in a first embodiment, and in front and/or back of the electronics in a second embodiment to transfer the total system heat load to water which then exited the frame.
While that patent solved many of the heat dissipation issues related to prior art, it did not address the air pressure drop through the angled heat exchangers, a problem especially in the case of side mounted sub-frame design.
Heat exchangers are typically designed to accept an air flow normal to its frontal area as shown in the prior art conventional heat exchanger design of
The shortcomings of the prior art are overcome and additional advantages are provided through the provision of an angled finned heat exchanger and incorporated method. The heat exchanger cools the air provided to the electronic components and is disposed at an angle with respect to direction of air flow. The heat exchanger comprises a plurality of fins that are at an angle with respect to frontal area of the heat exchanger. In alternate embodiments, the angle of the fin is optimized to minimize air pressure loss and/or drop. Some suggested methods of fabrication of the fins are also provided.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features, refer to the description and to the drawings.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Referring back to
In
The angled heat exchanger design is to provide for cooling rack-mounted modular electronic units in an attempt to address some of the defects existing in the prior art by combining the air cooling approach with an air-to-water heat exchanger fixed within the server cabinet. In this regard, the oblique heat exchanger 350 design of
Before a detailed discussion of the workings of the present invention is provided, however, the problem with using a traditional heat exchanger placed in an oblique angle needs to be further explored. Referring back to the prior art schematic illustration of a heat exchanger as provided by
The sectional cut view of the heat exchanger 250 illustrates the orientation of the fins 205. As can be observed, the air flows through the oblique angled fins 205 and is forced to change direction upon exiting the heat exchanger 250 again in substantially the same orientation as it entered the heat exchanger 250. This temporary changing of direction leads to the increased pressure drop in the air flow as discussed previously, ultimately causing less than optimal thermal management results.
This concept becomes more evident by examining the prior art illustration of
As discussed briefly in conjunction with
To remedy this problem, while maintaining the much desired side car configuration discussed, a first embodiment of the present invention is provided as illustrated in
As illustrated in
The pressure drop through the heat exchanger in an oblique orientation is primarily a function of the degree of air turning and the channel flow length. The degree of air turning is represented by an angle of attack ψ. Angle ψ is defined as the angle between the upstream air flow direction and the folded fins/channels and is related to the heat exchanger angle θ and fin angle φ as shown in
As illustrated
For example, an attack angle of zero degrees represents the “no air turning: configuration as was shown and discussed in conjunction with the embodiment of
As the angle of attack increases from a value of zero, however, the air turning contribution to pressure drop increases but the channel pressure drop decreases because of the decreasing channel flow length. A computational fluid dynamics analysis was undertaken to demonstrate that there is an optimum attack angle, and thus an optimum fin angle, for which pressure drop is a minimum. The results of the analysis are provided in
Note that angle φ, for this graph has been consistently kept at a value of 16.54 degrees as illustrated. At a zero attack angle, as shown, the air pressure drop value is 0.06 inches of water and this value actually decreases to less than 0.02 inches of water at around a 15 degree angle of attack and then from that point on the air pressure drop value increases. It should be noted that the example provided in the graph depicted in
The problem of optimizing the value of different angles including the angle of attack has now been explored and the attention can be turned to methods of manufacturing such an optimal folded fins with optimal angles. As will be appreciated by those skilled in the art, a variety of different embodiments can be used to achieve such fabrication goals. For ease of understanding, however, a couple of such methodologies will be explored below. As suggested, however, such methods are only provided as examples and should not be restrictive and limiting as with regards to the teaching of the present invention. A first and second method of fabricating a folded finned heat exchanger with an optimal angle is illustrated in
While the preferred embodiment to the invention has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.
Claims
1. A heat exchanger comprising:
- a plurality of fins angled with respect to a frontal area of said heat exchanger; and at least said frontal area being disposed at an angle with respect to direction of air flow.
2. The heat exchanger of claim 1, wherein said heat exchanger is disposed at an angle θ with respect to the air flow direction.
3. The heat exchanger of claim 2, wherein the fins are angled at an angle φ and value of φ is equal to 90−θ.
4. The heat exchanger of claim 3, wherein any necessary turning of air flow is measured by an angle ψ defined by relationship ψ=90−(θ+φ).
5. The heat exchanger of claim 1, wherein said heat exchanger comprises of a tubular structure placed horizontally with respect to gravity, said tubular structure being in thermal communication with said fins, such that said fins remain in complete circumferential contact with said heat exchanger.
6. The heat exchanger of claim 1, wherein fin angle is optimized to minimize air pressure drop.
7. The heat exchanger of claim 1, wherein said fins are folded fins.
8. The heat exchanger of claim 7, wherein said folded fins are made out of copper.
9. The heat exchanger of claim 7, wherein said folded fins have attached brass tubing for carrying fluids for fluid cooling.
10. The heat exchanger of claim 8, wherein said folded fins have attached brass tubing for carrying fluids for fluid cooling.
11. The heat exchanger of claim 1, wherein said heat exchanger is used in conjunction with a computing environment.
12. The heat exchanger of claim 11, wherein said heat exchanger is used in a server frame.
13. The heat exchanger of claim 12, wherein said heat exchanger is used in a side mounted sub-frame of a frame assembly housing a computing environment.
14. The heat exchanger of claim 12, wherein said heat exchanger is disposed such that air flow forms a closed loop and enters, exits and enters said heat exchanger as part of said closed air flow loop.
15. A method of cooling electronic components using a heat exchanger disposed at an angle with respect to direction of air flow comprising forming a plurality of angled fins provided such that are formed at an angle with respect to frontal area of said heat exchanger.
16. The method of claim 15, wherein said heat exchanger is disposed at an angle θ with respect to the air flow direction and said fins are angled at an angle φ and value of φ is equal to 90−θ.
17. The method of claim 16, wherein fin angle is optimized to minimize air pressure drop.
18. The method of claim 16, wherein said fins are formed by steps of: cutting a plurality of wide strips and recutting said wide strips to a desired width and at a preselected oblique angle.
19. The method of claim 16, wherein said fins are fabricated by stamping folded fins using gears with teeth at an oblique angle to gear axis to achieve desired fin angle.
20. The method of claim 16, wherein said fins are used in a computing environment.
Type: Application
Filed: May 25, 2006
Publication Date: Nov 29, 2007
Inventors: Levi A Campbell (Poughkeepsie, NY), Richard C. Chu (Hopewell Junction, NY), Michael J. Ellsworth (Lagrangeville, NY), Madhusudan K. Iyengar (Woodstock, NY), Roger R. Schmidt (Poughkeepsie, NY), Robert E. Simons (Poughkeepsie, NY)
Application Number: 11/420,237
International Classification: F28F 13/00 (20060101);