US20080011463A1

US20080011463A1 - Dual flow heat exchanger header

Info

Publication number: US20080011463A1
Application number: US11/488,106
Authority: US
Inventors: James F. Timbs; James W. Pickle; Colby W. Logan; John L. Bauer
Original assignee: Advanced Distributor Products LLC
Current assignee: Advanced Distributor Products LLC
Priority date: 2006-07-17
Filing date: 2006-07-17
Publication date: 2008-01-17

Abstract

An A-coil heat exchanger includes a header for receiving a heat transfer fluid after the fluid has passed through the interior of the heat exchanger. The header is comprised of a main body section and first and second tubular branches depending therefrom. The first tubular branch is in fluid communication with a first coil slab of the heat exchanger by means of a first set of adapter tubes extending between the first tubular section and the first coil slab. The second tubular branch is in fluid communication with a second coil slab of the heat exchanger by means of a second set of adapter tubes extending between the second tubular branch and the second coil slab. Each of the adapter tubes defines a generally straight section of conduit between the corresponding tubular branch and the corresponding coil slab. The header is located with respect to the coil slabs such that when the heat exchanger is positioned in an air stream, the header is substantially isolated from air flowing through the first and second coil slabs.

Description

TECHNICAL FIELD

This invention relates generally to heat exchangers used in air conditioning and refrigeration applications and in particular to heat exchangers of the A-coil type.

BACKGROUND ART

Heat exchangers are widely used in a variety of applications in the fields of air conditioning, refrigeration and the like. Typically, such heat exchangers are comprised of plural rows of tubes in which a first heat transfer fluid, such as water or a vapor compression refrigerant, flows while a second heat transfer fluid, such as air, is directed across the outside of the tubes. To improve heat transfer, a plurality of fins comprising thin sheets of metal are used. Each fin has multiple holes through which the tubes are laced and the fins are arranged in parallel, closely spaced relationship along the tubes to define multiple paths for the second heat transfer fluid to flow across the fins and around the tubes.
One type of heat exchanger often used in air conditioning and refrigeration applications is the so-called “A-coil” heat exchanger, an example of which is shown in FIG. 1. Referring now to FIG. 1, heat exchanger 10 is comprised of a pair of coil slabs 12, 14, which are coupled together at respective ends thereof by a connector plate 16 and are in divergent relationship to define a generally “A” shape. Each slab 12, 14 has plural tubes 18 laced through a plurality of fins 20. Tubes 18 are adapted to allow passage of a first heat transfer fluid (e.g., a vapor compression refrigerant) therethrough. Fins 20 are in parallel, closely spaced relationship and cooperate with tubes 18 to provide multiple paths for a second heat transfer fluid (e.g., air to be cooled) to flow across heat exchanger 10 on the outside of tubes 18.
Four rows of tubes 18 (two rows on each slab 12, 14) are shown in FIG. 1, by way of example. In other embodiments of an A-coil heat exchanger, the number of tube rows may be greater or less than two. Each tube row defines a discrete fluid circuit, with each circuit comprising multiple passes through the corresponding slab 12, 14. Return bends 22 connect distal ends of adjacent tubes 18. Tubes 18 penetrate through end plates 24 at the opposed ends of each slab 12, 14. Only one end plate 24 is shown on each slab 12, 14 in FIG. 1.
Four adapter tubes 26 connect the outlets of the respective tube circuits to an outlet header 28 in fluid communication with the suction side of a compressor (not shown) when heat exchanger 10 is used in a vapor compression air conditioning or refrigeration system. Header 28 extends horizontally across heat exchanger 10 proximate to the coupled ends of slabs 12, 14, and then bends upwardly at an approximately 90° angle. Although not shown in FIG. 1, plural distributor tubes connect the inlets of the respective tube circuits to an inlet header in fluid communication with the discharge side of the compressor. A drain pan (not shown) is preferably positioned under heat exchanger 10 to collect condensate runoff.
In operation, when heat exchanger 10 is used as an evaporator, the refrigerant enters heat exchanger 10 through the distributor tubes in substantially liquid form, makes multiple passes through heat exchanger 10 in each tube circuit, is substantially vaporized in heat exchanger 10 and exits heat exchanger 10 through adapter tubes 26. Further, when heat exchanger 10 is oriented in a “horizontal coil” configuration, as shown in FIG. 1, air or other fluid to be cooled flows horizontally into the region between slabs 12, 14 and horizontally outwardly through both slabs 12, 14, as indicated by arrows 29, whereby the air or other fluid is cooled. Header 28 is located such that the vertical portion thereof is in the air stream flowing outwardly from slab 12. Further, adapter tubes 26 are configured with multiple bends to enable adapter tubes 26 to be connected to selected ones of tubes 18.

SUMMARY OF THE INVENTION

In accordance with the present invention, a heat exchanger of the A-coil type having first and second coil slabs coupled at respective ends thereof and being in divergent relationship includes a header adapted to receive heat transfer fluid from the slabs. The header has a main section and first and second tubular branches sections depending therefrom. The first branch is in fluid communication with the first coil slab and the second branch is in fluid communication with the second coil slab.
In accordance with one embodiment of the invention, the heat exchanger further includes a first conduit in fluid communication between the first branch and the first coil slab and a second conduit in fluid communication between the second branch and the second coil slab.
In accordance with another embodiment of the invention, the first conduit defines a generally straight section of conduit between the first branch and the first coil slab and the second conduit defines a generally straight section of conduit between the second branch section and the second coil slab.
In accordance with yet another embodiment of the invention, the first conduit extends from the first branch in a first direction and the second conduit extends from the second branch in a second direction which is in divergent relationship to the first direction.
In accordance with still another embodiment of the invention, the header is located with respect to the first and second coil slabs such that when the heat exchanger is positioned in an air stream, the header is substantially isolated from air flowing through the first and second coil slabs.
In accordance with a preferred embodiment of the invention, the heat exchanger includes plural first conduits in fluid communication between the first branch and the first coil slab and plural second conduits in fluid communication between the second branch and the second coil slab. The first and second branches are in generally parallel relationship and extend generally parallel to an axis along which the first and second coil slabs are coupled.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a prior art A-coil heat exchanger;

FIG. 2 is a perspective view of an A-coil heat exchanger in accordance with an embodiment of the present invention;

FIG. 3 is an end elevation view of the A-coil heat exchanger of FIG. 2;

FIG. 4 is a side elevation view of the A-coil heat exchanger of FIG. 2;

FIG. 5 is a top plan view of the A-coil heat exchanger of FIG. 2; and

FIG. 6 is a perspective view of a header component used in the heat exchanger of FIG. 2.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the invention will now be described with reference to the accompanying drawings. Like parts are marked in the specification and drawings with the same respective reference numbers. In some instances, proportions may have been exaggerated in order to depict certain features of the invention.
Referring now to FIGS. 2-6, an A-coil heat exchanger 30 is comprised of first and second coil slabs 32, 34 that are coupled together at respective ends thereof by a connector plate 36 and are in divergent relationship to define a generally “A” shape. Each slab 32, 34 has plural heat transfer fluid carrying tubes 38, which are laced through a plurality of fins 40. Tubes 38 each have an internal passageway to accommodate the flow of a first heat transfer fluid (e.g., a vapor compression refrigerant) therethrough. Fins 40 are in parallel, closely spaced relationship and cooperate with tubes 38 to provide multiple paths for a second heat transfer fluid (e.g., air to be cooled) to flow across heat exchanger 30 on the outside of tubes 38. Heat is transferred from the second heat transfer fluid to the first heat transfer fluid.
Four rows of tubes 38 (two rows on each slab 32,34) are shown in FIG. 1, by way of example. One skilled in the art will recognize that the number of tube rows may be greater or less than two. Each tube row defines a discrete fluid circuit, with each circuit comprising multiple passes through the corresponding slab 32, 34. Return bends 42 connect distal ends of adjacent tubes 38. Tubes 38 penetrate through end plates 44 at the opposed ends of each slab 32,34. Only one end plate 44 is shown on each slab 32, 34 in FIG. 1.
As will be described in greater detail hereinbelow, a first pair of adapter tubes 46 and a second pair of adapter tubes 47 connect the outlets of the respective tube circuits to an outlet header 48 in fluid communication with the suction side of a compressor (not shown) when heat exchanger 30 is used in a vapor compression air conditioning or refrigeration system. When heat exchanger 30 is oriented for horizontal air flow, as shown in FIGS. 2-5, slabs 32, 34 are coupled together by connector plate 36 along a vertical axis. Header 48 is positioned with respect to the coupled ends of slabs 32, 34, such that no portion of header 48 would be located in a horizontal air stream flowing through slabs 32,34. Although not shown in FIGS. 2-5, heat exchanger 30 also includes plural distributor tubes connecting the inlets of the respective tube circuits to an inlet header in fluid communication with the discharge side of the compressor. A drain pan (not shown) is preferably positioned under heat exchanger 30 to collect condensate runoff.
In operation, when heat exchanger 30 is used as an evaporator, the refrigerant enters heat exchanger 30 through the distributor tubes in substantially liquid form, makes multiple passes through heat exchanger 30 in each tube circuit, is substantially vaporized in heat exchanger 30 and exits heat exchanger 30 through adapter tubes 46, 47. Further, when heat exchanger 30 is oriented in a “horizontal coil” configuration, as shown in FIGS. 2-5, air or other fluid to be cooled flows horizontally into the region between slabs 32, 34 and horizontally outwardly through both slabs 32, 34, as indicated by arrows 49, whereby the air or other fluid is cooled.
As can be best seen in FIG. 6, header 48 defines the general shape of a two-pronged fork and is comprised of a main body section 50 and first and second tubular branches 52, 54 depending therefrom. Branches 52, 54 are in parallel relationship. Respective major axes of main body section 50 and tubular branches 52, 54 are oriented along respective vertical axes parallel to the vertical axis along which slabs 32,34 are coupled together. Main body section 50 has a flared open end 50 a, which is adapted to connect header 48 to a compressor suction line (not shown). An opposite end of main body section 50 is defined by a bulbous portion 50 b containing first and second sockets (not shown) in which respective open ends of first and second tubular branches 52,54 are received. The respective opposite ends of tubular branches 52, 54 are closed. First tubular branch 52 is in fluid communication with first coil slab 32 by means of adapter tubes 46, which extend horizontally outwardly from first tubular branch 52 along respective axes that are perpendicular to the major axis of first tubular branch 52. Second tubular branch 54 is in fluid communication with second coil slab 34 by means of adapter tubes 47, which extend horizontally outwardly from second tubular branch 54 along respective axes that are perpendicular to the major axis of second tubular branch 54.
Adapter tubes 46 are in divergent relationship with respect to adapter tubes 47, corresponding to the divergent relationship between slabs 32 and 34. Further, the two tubes 46 are stacked vertically one above the other and the two tubes 47 are stacked vertically one above the other, so that each adapter tube 46, 47 defines a generally straight section of conduit between the corresponding tubular branch 52, 54 and the corresponding coil slab 32, 34. One skilled in the art will recognize that the aforementioned configuration of adapter tubes 46,47 eliminates the need for one or more bends in the adapter tubes characterized by prior art A-coil heat exchangers.
As can be best seen in FIG. 3, main body section 50 and first and second branches 52,54 are oriented vertically and extend generally parallel to a vertical axis along which first and second coil slabs 32, 34 are coupled by connector plate 36. Header 48 is located with respect to coil slabs 32, 34 such that when heat exchanger 30 is positioned in a horizontal air stream, header 48 is substantially isolated from air flowing through first and second coil slabs 32, 34.
The best mode for carrying out the invention has now been described in detail. Since changes in and modifications to the above-described preferred embodiment may be made without departing from the nature, spirit and scope of the invention, the invention is not to be limited to said details, but only by the appended claims and their equivalents.

Claims

1. In a heat exchanger having first and second coil slabs coupled at respective ends thereof and being in diverging relationship to define an A-coil configuration, each of said slabs having at least one heat transfer carrying tube, wherein the improvement comprises a header adapted to receive heat transfer fluid from said slabs, said header having a main section and first and second branch sections depending therefrom, said first branch section being in fluid communication with said first coil slab and said second branch section being in fluid communication with said second coil slab.

2. The heat exchanger of claim 1 further including a first conduit in fluid communication between said first branch section and said first coil slab and a second conduit in fluid communication between said second branch section and said second coil slab.

3. The heat exchanger of claim 2 wherein said first conduit defines a generally straight section of conduit between said first branch section and said first coil slab and said second conduit defines a generally straight section of conduit between said second branch section and said second coil slab.

4. The heat exchanger of claim 2 further including plural first conduits in fluid communication between said first branch section and said first coil slab and plural second conduits in fluid communication between said second branch section and said second coil slab.

5. The heat exchanger of claim 2 wherein said first conduit extends from said first branch section in a first direction and said second conduit extends from said second branch section in a second direction which is in divergent relationship to said first direction.

6. The heat exchanger of claim 1 wherein said first and second branch sections are in generally parallel relationship.

7. The heat exchanger of claim 6 wherein said main section and said first and second branch sections extend generally parallel to an axis along which said first and second coil slabs are coupled.

8. The heat exchanger of claim 1 wherein said heat exchanger is positionable for horizontal air flow therethrough, said main section and said first and second branch sections having respective major axes that are in parallel relationship, said respective major axes being oriented vertically when said heat exchanger is positioned for horizontal air flow therethrough.

9. The heat exchanger of claim 1 wherein said header is located proximate to the coupled ends of said first and second coil slabs such that when said heat exchanger is positioned in an air stream, said header is substantially isolated from air flowing through said first and second coil slabs.

10. A header adapted for connection to an A-coil heat exchanger to receive heat transfer fluid therefrom, said header comprising a main section and first and second branch sections depending therefrom, said first branch section being adapted to receive heat transfer fluid from a first portion of the heat exchanger and said second branch section being adapted to receive heat transfer fluid from a second portion of the heat exchanger.

11. The header of claim 10 further including at least one first conduit extending from said first branch section and being adapted to feed heat transfer fluid from the first portion of the heat exchanger to said first branch section, said header further including at least one second conduit extending from said second branch section and being adapted to feed heat transfer fluid from the second portion of the heat exchanger to said second branch section.

12. The header of claim 11 wherein said first conduit defines a generally straight first section of conduit and said second conduit defines a generally straight second section of conduit.

13. The header of claim 11 further including plural first conduits extending from said first branch section and plural second conduits extending from said second branch section.

14. The header of claim 11 wherein said first conduit extends from said first branch section in a first direction and said second conduit extends from said second branch section in a second direction which is in divergent relationship to said first direction.

15. The header of claim 10 wherein said first and second branch sections are in generally parallel relationship.

16. The header of claim 15 wherein said main section and said first and second branch sections each have a major axis and a minor axis, the respective major axes of said main section and said first and second branch sections being in generally parallel relationship.

17. In combination:

a heat exchanger having first and second coil slabs coupled at respective ends thereof and being in diverging relationship to define an A-coil configuration, each of said slabs having a passageway adapted for heat transfer fluid to pass therethrough; and

a header in fluid communication with said slabs to receive heat transfer fluid after the fluid has passed through said slabs, said header having a main body section and first and second tubular branches depending therefrom, said first tubular branch being in fluid communication with said first coil slab and said second tubular branch being in fluid communication with said second coil slab, said header being located proximate to the coupled ends of said first and second coil slabs such that when said heat exchanger is positioned in an air stream, said header is substantially isolated from air flowing through said first and second coil slabs.

18. The combination of claim 17 further including plural first conduits in fluid communication between said first tubular branch and said first coil slab and plural second conduits in fluid communication between said second tubular branch and said second coil slab.

19. The combination of claim 18 wherein said each of first conduits defines a generally straight section of conduit between said first tubular branch and said first coil slab and each of said second conduits defines a generally straight section of conduit between said second tubular branch and said second coil slab.

20. The combination of claim 19 wherein said first conduits extend from said first tubular branch section in respective first directions and said second conduits extend from said second tubular branch in respective second directions which are in divergent relationship to said respective first directions.