MICROCHANNEL HEAT EXCHANGER FIN
A heat exchanger includes a plurality of tubes (12), each tube configured for a flow of fluid therethrough and one or more fins located between adjacent tubes of the plurality of tubes. The one or more fins are spaced by a fin pitch (Fp,18) and are configured to improve thermal energy transfer between the plurality of tubes and ambient air. Each fin includes a fin face extending between the adjacent tubes, a substantially planar fin cap (22) connected to the fin face secured to one or the tubes, and a fin radius (Rc,26) connecting the fin face to the fin cap such that the fin radius is reduced to promote condensate removal from the heat exchanger.
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The subject matter disclosed herein relates to heat exchangers. More specifically, the subject disclosure relates to fin and tube configurations for microchannel heat exchangers.
Heating, ventilation, air conditioning and refrigeration (HVAC & R) systems include heat exchangers to reject or accept heat between the refrigerant circulating within the system and surroundings. One type of the heat exchanger that has become increasingly popular, due to its compactness, structural rigidity and superior performance is a microchannel or minichannel heat exchanger (MCHX) which includes two or more containment forms, such as tubes, through which a cooling or heating fluid (such as refrigerant or glycol solution) is circulated. The tubes typically have a flattened cross-section and multiple parallel channels. Fins are typically arranged to extend between the tubes to aid in the transfer of thermal energy between the cooling/heating fluid and the surrounding environment. The fins have a corrugated pattern, incorporate louvers to boost heat transfer and are typically secured to the tubes via brazing. Typical MCHX fin and tube arrangements, however, have the disadvantage of retaining large quantities of moisture, water or condensate, within the fin and tube structure, due to their high compactness and thus increased surface tension. The accumulated moisture accelerates corrosion of the fin and tube structure which leads to decreased thermo-hydraulic performance or effectiveness of the heat exchanger and eventual failure of the heat exchanger when the tubes are corroded sufficiently to be perforated, thus releasing the cooling/heating fluid. Further, along with retention of moisture, the typical structure leads to the buildup of corrodant substances and mechanical stresses in the structure leading to stress corrosion which further accelerates deterioration of the fin and tube structure and resultant failure of the heat exchanger. The art would well receive a fin and tube structure which reduces the accumulation of moisture in the heat exchanger matrix thereby reducing corrosion of the heat exchanger.
BRIEF DESCRIPTION OF THE INVENTIONAccording to one aspect of the invention, a heat exchanger includes a plurality of tubes, each tube configured for a flow of fluid therethrough and one or more fins located between adjacent tubes of the plurality of tubes. The one or more fins are spaced by a fin pitch (FP) and are configured to improve thermal energy transfer between the plurality of tubes and ambient air. Each fin includes a fin face extending between the adjacent tubes, a substantially planar fin cap connected to the fin face secured to one or the tubes, and a fin radius (RC) connecting the fin face to the fin cap such that the fin radius is minimized to promote removal of condensate from the heat exchanger.
According to another aspect of the invention, a heat exchanger includes a plurality of tubes, each tube configured for a flow of fluid therethrough. One or more fins are located between adjacent tubes of the plurality of tubes. The one or more fins are spaced by a fin pitch (FP) and are configured to improve thermal energy transfer between the plurality of tubes and ambient air. Each fin includes a fin extension extending beyond a tube width. The extended portion of the fin is laterally flared and shaped to reduce capillary effects and enhance water drainage.
These and other advantages and features will become more apparent from the following description taken in conjunction with 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 features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTIONShown in
Referring now to
Each fin face 20 includes a plurality of through openings, for example, louvers 24 arrayed along a lateral extent of the fin 16. The louvers 24 improve heat transfer and also assist in reducing water retention in the heat exchanger by providing an alternate passage for moisture, water, and/or condensate to drain through the heat exchanger 10. A transition between each fin cap 22 and fin face 20 is a fin radius (RC) 26. It is desired to reduce the fin radius 26 in order for a louver height (LH) 28 to be increased relative to a fin height (FH) 30, thus increasing an overall size of the louver 24 opening within the fin 16. In some embodiments, a ratio of louver height 28 to fin height 30, LH/FH, is between about 0.8 and about 0.95, and the preferred range is between about 0.85 and about 0.92. Further, the fin radius 26 relates to fin pitch 18 such that a ratio of fin radius 26 to fin pitch 18, RC/FP, is between about 0.1 and about 0.4. The preferred range of RC/FP is between about 0.2 and about 0.3
Referring now to
Referring now to
Nw/(FP−Sqrt(FH2−(TP−TT)2)
In some embodiments, the relationship equals about 0.3 to about 0.9, while the preferred range of the relationship is about 0.4 to about 0.7.
Another embodiment is illustrated in
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
Claims
1. A heat exchanger comprising:
- a plurality of tubes, each tube configured for a flow of fluid therethrough;
- one or more fins disposed between adjacent tubes of the plurality of tubes, the one or more fins spaced by a fin pitch (FP) and configured to improve thermal energy transfer between the plurality of tubes and ambient air, each fin including: a fin face extending between the adjacent tubes; a substantially planar fin cap connected to the fin face secured to one or the tubes; and a fin radius (RC) connecting the fin face to the fin cap such RC is reduced to promote condensate flow from the heat exchanger.
2. The heat exchanger of claim 1 such that a ratio of the fin radius to the fin pitch, RC/FP, is between about 0.1 and about 0.4.
3. The heat exchanger of claim 2, wherein the ratio of the fin radius to the fin pitch, RC/FP, is between about 0.2 and about 0.3.
4. The heat exchanger of claim 1, wherein each fin face includes one or more louvers.
5. The heat exchanger of claim 4, wherein a ratio of a louver height (LH) to a fin height (FH), LH/FH, is between about 0.8 and about 0.95.
6. The heat exchanger of claim 5, wherein LH/FH, is between about 0.85 and about 0.92.
7. The heat exchanger of claim 1, wherein each fin includes a fin extension extending beyond a tube width.
8. The heat exchanger of claim 7, wherein the fin extension extends laterally beyond the tube width and transversely at least partially across a tube thickness.
9. The heat exchanger of claim 7, wherein the fin extension is configured to direct moisture accumulated in the fin structure away from the tubes.
10. The heat exchanger of claim 7, wherein a ratio of an extension width (EW) to a fin width (FW), EW/FW is between about 0.02 and about 0.1.
11. The heat exchanger of claim 10, wherein EW/FW is between about 0.02 and about 0.04.
12. The heat exchanger of claim 7, wherein a ratio of a transverse component (ET) of the fin extension to a tube thickness (TT), ET/TT, is between about 0.05 and about 0.4.
13. The heat exchanger of claim 12, wherein ET/TT is between about 0.05 and about 0.15.
14. The heat exchanger of claim 7, wherein a ratio of a transverse component (ET) of the fin extension to a fin thickness (FT), ET/FT, is between about 1 and about 3.
15. The heat exchanger of claim 14, wherein ET/FT, is between about 1.75 and about 2.5.
16. The heat exchanger of claim 7, wherein a ratio of a transverse component (ET) of the fin extension to the fin radius, ET/RC, is between about 0.2 and about 2.
17. The heat exchanger of claim 1, wherein each fin of the one or more fins spans two or more tubes along a fin width.
18. The heat exchanger of claim 17, wherein each fin includes a fin notch in the fin face disposed substantially aligned with a tube gap between two tubes of the two or more tubes.
19. The heat exchanger of claim 18, wherein a ratio of a notch height (NH) to a tube pitch (TP), NH/TP, is between about 0.15 and about 0.3.
20. The heat exchanger of claim 19, wherein NH/TP, is between about 0.1 and about 0.2.
21. The heat exchanger of claim 1, wherein each tube of the plurality of tubes, includes a through slot extending along a length of the tube.
22. The heat exchanger of claim 21, wherein a ratio of a slot width (SW) to a tube width (TW), SW/TW, is between about 0.05 and about 0.2.
23. The heat exchanger of claim 21, wherein a ratio of slot length (SL) to a tube length (TL), SL/TL, is between about 0.8 and about 0.95.
24. A heat exchanger comprising:
- a plurality of tubes, each tube configured for a flow of fluid therethrough;
- one or more fins disposed between adjacent tubes of the plurality of tubes, the one or more fins spaced by a fin pitch (Fp) and configured to improve thermal energy transfer between the plurality of tubes and ambient air, each fin including a fin extension extending beyond a tube width.
25. The heat exchanger of claim 24, wherein the fin extension is configured to direct moisture accumulated in the fin structure away from the tubes.
26. The heat exchanger of claim 24, wherein a ratio of an extension width (EW) to a fin width (FW), EW/FW is between about 0.02 and about 0.1.
27. The heat exchanger of claim 26, wherein EW/FW is between about 0.02 and about 0.04.
28. The heat exchanger of claim 24, wherein a ratio of a transverse component (ET) of the fin extension to a tube thickness (TT), ET/TT, is between about 0.05 and about 0.4.
29. The heat exchanger of claim 28, wherein ET/TT is between about 0.05 and about 0.15.
30. The heat exchanger of claim 24, wherein a ratio of a transverse component (ET) of the fin extension to a fin thickness (FT), ET/FT, is between about 1 and about 3.
31. The heat exchanger of claim 30, wherein ET/FT, is between about 1.75 and about 2.5.
32. The heat exchanger of claim 24, wherein each fin includes:
- a fin face extending between the adjacent tubes and;
- a substantially planar fin cap connected to the fin face secured to one or the tubes; and
- a fin radius (RC) connecting the fin face to the fin cap such that a ratio of the fin radius to the fin pitch, RC/FP, is between about 0.1 and about 0.4.
33. The heat exchanger of claim 32, wherein the ratio of the fin radius to the fin pitch, RC/FP, is between about 0.2 and about 0.3.
34. The heat exchanger of claim 32, wherein each fin face includes one or more louvers.
35. The heat exchanger of claim 34, wherein a ratio of a louver height (LH) to a fin height (FH), LH/FH, is between about 0.8 and about 0.95.
36. The heat exchanger of claim 35, wherein LH/FH, is between about 0.85 and about 0.92.
Type: Application
Filed: Aug 9, 2011
Publication Date: Jun 20, 2013
Applicant: CARRIER CORPORATION (Farmington, CT)
Inventors: Michael F. Taras (Fayetteville, NY), Arindom Joardar (East Syracuse, NY), Jack Leon Esformes (Jamesville, NY), Sunil S. Mehendale (Manlius, NY)
Application Number: 13/818,386
International Classification: F28F 1/12 (20060101);