NESTED HEAT EXCHANGER

Abstract

A heat exchanger assembly includes at least first and second coils adapted to contain a fluid therein and at least two support members securing the coils. Each of the first and second coils are individually formed of at least one tube including an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof and include a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration. The first and second coils are adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first coil are disposed between adjacent pairs of the horizontal rows of the second coil.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/610,269, filed Mar. 13, 2012, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention generally relates to heat exchangers. More particularly, this invention relates to a heat exchanger having coolant tubes that overlap.

Heat exchangers are widely used in various industries in the form of radiators for cooling motors, engines, and steering, transmission and hydraulic fluids, condensers and evaporators for use in air conditioning systems, and heaters. In their most simple form, heat exchangers include one or more passages through which a fluid flows while exchanging heat with the environment surrounding the passage. In order to efficiently maximize the amount of surface area available for transferring heat between the environment and fluid, the design of a heat exchanger is typically of a tube-and-fin type containing a number of tubes that thermally communicate with fins. The fins enhance the ability of the heat exchanger to transfer heat from the fluid to the environment, or vice versa. Various heat exchanger designs are known in the prior art. Design variations include the manner in which the fluid passage is constructed and the type of fin used. For example, the passage may be composed of one or more serpentine tubes that traverse the heat exchanger in a circuitous manner, or a number of discrete parallel tubes joined, typically brazed, to and between a pair of headers. The fins may be provided in the form of panels having apertures through which the tubes are inserted, or in the form of centers that can be positioned between adjacent pairs of tubes.

In traditional serpentine heat exchangers, a refrigerant flows up and down through a tube (coil) across the heat exchanger (the terms “up” and “down” are used herein to refer to the orientation of a heat exchanger to earth, are relative terms that indicate the construction, installation and use of a heat exchanger, and therefore help to define the scope of the invention). The effective rate of heat transfer between the fluid and the outside environment are limited by the amount of coils the are in the heat exchangers. Improvements to heat exchangers are continuously sought to increase the rate of heat transfer.

Accordingly, there is a need for a heat exchanger assembly adapted to promote an increased rate of heat transfer between the fluid and the environment surrounding the heat exchanger.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides heat exchangers having coils that are nested in order to increase the coolant tube density within the heat exchanger and thereby promote an increased rate of heat transfer between the fluid and the environment surrounding the coils.

According to a first aspect of the invention, a heat exchanger assembly includes at least first and second coils adapted to contain a fluid therein and at least two support members securing the coils to each other. Each of the first and second coils are individually formed of at least one tube comprising an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof and include a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration. The first and second coils are adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first coil are disposed between adjacent pairs of the horizontal rows of the second coil.

According to a second aspect of the invention, a heat exchanger assembly includes at least first and second coils adapted to contain a fluid therein and at least two support members securing the first and second coils together. Each of the first and second coils are individually formed of at least one tube comprising an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof. Each of the first and second coils comprising a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration through which the fluid flows downward from the inlet thereof to the outlet thereof. The first and second coils are adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first and second coils are interdigitated with each other.

According to a third aspect of the invention, a heat exchanger assembly includes at least first and second coils adapted to contain a fluid therein and at least two support members securing the first and second coils to each other. Each of the first and second coils are individually formed of at least one tube comprising an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof. Each of the first and second coils comprising a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration through which the fluid flows downward from the inlet thereof to the outlet thereof. The first and second coils are adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first and second coils are interdigitated with each other. The heat exchanger assembly includes at least one vertical section fluidically connecting the outlet of the first coil to the inlet of the second coil, wherein the fluid flowing within the heat exchanger assembly travels from the outlet of the first coil, up through the vertical section, and into the inlet of the second coil.

A technical effect of the invention is the ability to provide an increased rate of heat transfer in a heat exchanger without increasing the size of the heat exchanger. In particular, it is believed that, by nesting the coils, the amount of coils within the heat exchanger may be increased without increasing the size of the heat exchanger thereby promoting an increased rate of heat transfer between the fluid and the environment surrounding the coils.

Other aspects and advantages of this invention will be better appreciated from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 includes side and end views representing a coil in accordance with an aspect of the invention.

FIG. 2 is a perspective view representing a heat exchanger assembly in accordance with an aspect of the invention.

FIG. 3 is an end view representing the heat exchanger assembly of FIG. 2.

FIG. 4 is a bottom view representing the heat exchanger assembly of FIG. 3.

FIG. 5 is a perspective view representing a heat exchanger assembly in accordance with an aspect of the invention.

FIG. 6 is an end view representing the heat exchanger assembly of FIG. 5.

FIG. 7 is a bottom view representing the heat exchanger assembly of FIG. 6.

FIGS. 8 and 9 include top, end, and side views representing support members in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 2 through 9 represent a nested heat exchanger assembly 10 according to non-limiting embodiments of the present invention. The heat exchanger assembly 10 is adapted to contain a fluid within coils 12 for promoting heat exchange between the fluid and the environment surrounding the coils 12. Suitable fluids include, but are not limited to, CO₂, propane, and other gasses and liquids commonly used for heat exchange. The heat exchanger assembly 10 may be formed of any suitable material, for example, ferris metal, non-ferris metal, plastic, and glass. For convenience, consistent reference numbers are used throughout the figures to identify the same or functionally equivalent elements. To facilitate the description of the heat exchanger assembly 10, the terms “front,” “back,” “side,” “above,” “below,” etc., are used herein to refer to the orientation of a heat exchanger to earth, are relative terms that indicate the construction, installation and use of a heat exchanger, and therefore help to define the scope of the invention.

The heat exchanger assembly 10 is represented in FIG. 2 as comprising four coils 12 connected by an inlet assembly 22 at the top of the heat exchanger assembly 10, or uppermost extent of the coils 12, and an outlet assembly 24 at the bottom of the heat exchanger assembly 10, or lowermost extent of the coils 12. FIGS. 2, 3, and 4 represent perspective, end, and bottom end views of a first embodiment of the heat exchanger assembly 10, respectively.

Each of the coils 12 are individually formed of at least one tube 14 defining a serpentine pattern as represented in FIG. 1. Preferably, the coils 12 are each formed from a single continuous tube 14. The tubes 14 comprise an inlet at an uppermost extent of the coils 12 and an outlet at a lowermost extent of the coils 12. The coils 12 are defined by a vertical column containing a plurality of horizontal rows 15 spanning the length of the heat exchanger assembly 10 and a plurality of bends 16 at opposing ends of the heat exchanger assembly 10 and fluidically interconnecting the horizontal rows 15 thereof in series to define a serpentine configuration. The horizontal rows 15 and bends 16 form the serpentine pattern, as represented in FIG. 1, defined by an end of a first horizontal row spanning the length of the heat exchanger assembly 10 being fluidically connected to a first end of a second horizontal row by a first bend 16. The second horizontal row 15 being closer to the lowermost extent of the coil 12 than the first horizontal row 15. The serpentine pattern is continued by fluidically connecting a second end of the second horizontal row 15 to an end of a third horizontal row by a second bend 16. The third horizontal row 15 being closer to the lowermost extent of the coil 12 than the second horizontal row 15. The serpentine pattern is continued until reaching the outlet at the lowermost extent of the coil 12.

The bends 16 on the ends of the coil 12 are arranged on opposite ends of the coil 12. The bends 16 are angled down toward the lowermost extent of the coils 12. Preferably, the bends 16 on opposite ends of the coil 12 are and are disposed in planes that are not horizontal and not parallel to each other to define an angle theta (θ) to one another, as represented in FIG. 3. Preferably, the angle theta (θ) is about 60 degrees. However, one skilled in the art will appreciate that the angle theta (θ) is dependent on the outside diameter, wall thickness, and formability of the tubes 14.

FIGS. 2 and 3 represent the heat exchanger assembly 10 as comprising four coils 12 arranged in adjacent vertical columns. The horizontal rows 15 of each coil 12 are positioned parallel to the horizontal rows 15 of the other coils 12. It will be appreciated that the heat exchanger assembly 10 may comprise any number of coils 12. In operation, a fluid enters the inlet assembly 22 at the uppermost extent of the coils 12, the fluid enters each of the four coils 12 generally simultaneously, and travels downward fluidically in parallel through the coils 12 to the outlet assembly 24 at the lowermost extent of the coils 12 where the fluid may exit the heat exchanger assembly 10. A detailed bottom view of an end of the heat exchanger assembly 10 is represented in FIG. 4. The tubes 14 of the coils 12 are represented as being secured to each other by support members 18 at both ends of the heat exchanger assembly 10. The support members 18 may comprise flanges 26 to secure the heat exchanger assembly to another structure, for example, to a frame of a motor vehicle. The flanges 26 may be constructed in any shape suitable for the intended application.

FIGS. 5, 6, and 7 represent perspective, end, and bottom end views of an alternative embodiment of the heat exchanger assembly 10, respectively. In this embodiment, the heat exchanger assembly 10 is represented as comprising three vertical sections 28 fluidically connecting the outlets of coils 12 at the lowermost extent of the coils 12 to the inlets of adjacent coils 12 at the uppermost extent of the adjacent coils 12. In operation, the fluid travels through the entirety of one of the coils 12 prior to entering the next adjacent coil 12 and thereby traveling through the coils 12 fluidically in series rather than through all of the coils 12 at once fluidically in parallel, as was the case in the embodiment of FIGS. 2-4. The fluid enters the inlet assembly 22 at the uppermost extent of a first of the coils 12 and travels downward through the first coil 12. Once the fluid reaches the lowermost extent of the first coil 12, the fluid then travels from the outlet of the first coil 12 up through one of the vertical sections 28 into the inlet of a second coil 12. This process is repeated until the fluid travels through the entirety of all of the coils 12. The fluid can then exit a last of the coils 12 through the outlet assembly 24. In addition to the two embodiments of the invention described above, it is foreseeable that the heat exchanger assembly 10 can comprise a combination of the above arrangements of the coils 12 wherein the fluid travels through some of the coils 12 in series, as in the embodiment of FIGS. 5 through 7, and through other coils 12 generally simultaneously, as in the embodiment of FIGS. 2-4.

In FIGS. 3 and 6, horizontal rows of the coils 12 are represented as being nested, that is, having at least some of the horizontal rows 15 on a first coil 12 disposed between adjacent pairs of the horizontal rows 15 of a second coil 12 adjacent to the first coil 12. Preferably, a plurality of the horizontal rows 15 on the first coil 12 are interdigitated with the horizontal rows 15 of the second coil 12. It is believed that fitting the coils 12 together in this manner allows more of the tubes 14 to fit in the same amount of space thereby promoting an increased rate of heat transfer between the fluid within the coils 12 and the environment surrounding the coils 12 relative to other heat exchangers of equal size. The heat exchanger assembly 10 may be used for both standard and high pressure applications having an appropriate tube wall material thickness. The tubes 14 can be made of any suitable material including, but not limited to, steel, stainless steel, copper, polymer, glass or aluminum tubes. The tubes 14 can be made to have a suitable outside diameter, for example, in a range of about 0.2 inch to about one inch (about 5 to about 25 millimeters), though other dimensions are foreseeable. As a non-limiting example, it is believed that a tube 14 formed of carbon steel having an outside diameter of about 0.375 inch (about 9.5 mm) and a wall thickness of about 0.028 inch (about 0.71 mm) can survive operating pressures up to about 2,200 psi (15.2 Mpa). Connectors (not shown) may be attached to the ends of the coils 14 (or inlet assembly 22 and outlet assembly 24), for example, copper connectors. The heat exchanger assembly 10 may further be modified for particular applications by selecting the number of tubes 14 in the coil 12, selecting the number of columns of the tube 14 in the coil 12, and/or selecting the radius and the degree of twist on the bends 16 of the tube 14.

To improve heat transfer, one or more fins 20 may be attached to the coils 12, as represented in FIGS. 2, 5, and 7. Various shapes of the fins 20 may be used to increase performance of the heat exchanger assembly 10 including, but not limited to, straight, corrugated and lanced fin shapes. The fins 20 may be made of any suitable material such as steel, stainless steel, copper, aluminum, galvanized steel or a polymer material. Further, the fins 20 may have a finish coating such as a hydrophilic, latex, or electrodeposition coating. However, depending on the application, it may be desirable to limit the number of fins 20 attached to the coils 12. It is believed that addition of the fins 20 to the heat exchanger assembly 10 increases the likelihood of debris from an outside environment accumulating around the coils 12 which may act to insulate the coils 12 reducing the rate of heat transfer of the heat exchanger assembly 10.

FIGS. 7 and 8 include top, side, and back views representing various flange 26 arrangements of the support member 18. As represented, the support member 18 may comprise extrusions 30 that encircle and contact the tubes 14 of the coils 12. The extrusions 30 may also be formed on the fins 20 (not shown). The extrusions 30 allow for increased surface area contact between the tubes 14 and support member 18 thereby increasing thermal transfer. The extrusions 30 may further promote accurate fin spacing and support member alignment.

While the invention has been described in terms of specific embodiments, it is apparent that other forms could be adopted by one skilled in the art. For example, the physical configuration of the heat exchanger assembly 10 could differ from that shown, and materials and processes other than those noted could be used. Therefore, the scope of the invention is to be limited only by the following claims.

Claims

1. A heat exchanger assembly comprising:

at least first and second coils adapted to contain a fluid therein, each of the first and second coils being individually formed of at least one tube comprising an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof, each of the first and second coils comprising a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration, the first and second coils being adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first coil are disposed between adjacent pairs of the horizontal rows of the second coil; and

at least two support members securing the coils to each other.

2. The heat exchanger assembly according to claim 1, wherein the support members comprise extrusions adapted to increase a contact area between the support members and the first and second coils.

3. The heat exchanger assembly according to claim 1, further comprising at least one fin attached to the first and second coils of the heat exchanger assembly.

4. The heat exchanger assembly according to claim 3, wherein the fin comprises extrusions adapted to increase a contact area between the fin and the first and second coils.

5. The heat exchanger assembly according to claim 1, wherein the heat exchanger assembly causes the fluid therein to simultaneously flow through the first and second coils fluidically in parallel.

6. The heat exchanger assembly according to claim 1, wherein the heat exchanger assembly is adapted to cause the fluid therein to flow through the first and second coils fluidically in series.

7. The heat exchanger assembly according to claim 6, further comprising at least one vertical section fluidically connecting the outlet of the first coil to the inlet of the second coil, wherein the fluid flowing within the heat exchanger assembly travels from the outlet of the first coil, up through the vertical section, and into the inlet of the second coil.

8. The heat exchanger assembly according to claim 1, wherein the bends at oppositely-disposed ends of each of the horizontal rows of the first and second coils are disposed in planes that are not horizontal and not parallel to each other.

9. The heat exchanger assembly according to claim 1, wherein the fluid is CO2.

10. The heat exchanger assembly according to claim 1, wherein the heat exchanger assembly is adapted to operate at a pressure of up to about 15.2 Mpa.

11. A heat exchanger assembly comprising:

at least first and second coils adapted to contain a fluid therein, each of the first and second coils being individually formed of at least one tube comprising an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof, each of the first and second coils comprising a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration through which the fluid flows downward from the inlet thereof to the outlet thereof, the first and second coils being adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first and second coils are interdigitated with each other; and

at least two support members securing the first and second coils together.

12. The heat exchanger assembly according to claim 11, wherein the heat exchanger assembly causes the fluid therein to simultaneously flow through the first and second coils fluidically in parallel.

13. The heat exchanger assembly according to claim 11, wherein the heat exchanger assembly is adapted to cause the fluid therein to flow through the first and second coils fluidically in series.

14. The heat exchanger assembly according to claim 13, further comprising at least one vertical section fluidically connecting the outlet of the first coil to the inlet of the second coil, wherein the fluid flowing within the heat exchanger assembly travels from the outlet of the first coil, up through the vertical section, and into the inlet of the second coil.

15. The heat exchanger assembly according to claim 11, wherein the fluid is CO2.

16. The heat exchanger assembly according to claim 11, wherein the heat exchanger assembly is adapted to operate at a pressure of up to about 15.2 Mpa.

17. A heat exchanger assembly comprising:

at least first and second coils adapted to contain a fluid therein, each of the first and second coils being individually formed of at least one tube comprising an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof, each of the first and second coils comprising a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration through which the fluid flows downward from the inlet thereof to the outlet thereof, the first and second coils being adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first and second coils are interdigitated with each other;

at least one vertical section fluidically connecting the outlet of the first coil to the inlet of the second coil, wherein the fluid flowing within the heat exchanger assembly travels from the outlet of the first coil, up through the vertical section, and into the inlet of the second coil; and

at least two support members securing the first and second coils to each other.

18. The heat exchanger assembly according to claim 17, wherein the heat exchanger assembly causes the fluid therein to flow through the first and second coils fluidically in series.

19. The heat exchanger assembly according to claim 17, wherein the fluid is CO2.

20. The heat exchanger assembly according to claim 17, wherein the heat exchanger assembly is adapted to operate at a pressure of up to about 15.2 Mpa.