EP3334991A1

EP3334991A1 - Microchannel heat exchanger

Info

Publication number: EP3334991A1
Application number: EP16753806.5A
Authority: EP
Inventors: Jason Scarcella
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2015-08-14
Filing date: 2016-08-12
Publication date: 2018-06-20
Anticipated expiration: 2036-08-12
Also published as: WO2017030922A1; CN107923712A; EP3334991B1

Abstract

A heat exchanger is provided including a first manifold, a second manifold separated from the first manifold, and a plurality of heat exchange tube segments arranged in spaced parallel relationship and fluidly coupling the first manifold and the second manifold. The plurality of heat exchange tube segments include a fold forming a first tube bank and a second tune bank in substantially parallel relation to one another along at least a portion of a length of the plurality of heat exchange tube segments. The first tube bank and the second tube bank are configured for sequential flow there through of a first heat transfer fluid.

Description

MICROCHANNEL HEAT EXCHANGER

BACKGROUND

[0001] This disclosure relates generally to heat pump and refrigeration applications and, more particularly, to a microchannel heat exchanger configured for use in a heat pump or refrigeration system.

[0002] Heating, ventilation, air conditioning and refrigeration (HVAC&R) systems include heat exchangers to transfer heat between the refrigerant circulating within the system and surroundings. In recent years, much interest and design effort has been focused on the efficient operation of heat exchangers of refrigerant systems, particularly condensers and evaporators. A relatively recent advancement in heat exchanger technology includes the development and application of parallel flow (also referred to as microchannel or minichannel) heat exchangers as condensers and evaporators.

[0003] Microchannel heat exchangers are provided with a plurality of parallel heat exchange tubes, each of which has multiple flow passages through which refrigerant is distributed and flown in a parallel manner. The heat exchange tubes can be orientated substantially perpendicular- to a refrigerant flow direction in the inlet, intermediate and outlet manifolds that are in flow communication with the heat exchange tubes.

SUMMARY

[0004] According to an embodiment, a heat exchanger is provided including a first manifold, a second manifold separated from the first manifold, and a plurality of heat exchange tube segments arranged in spaced parallel relationship and fluidly coupling the first manifold and the second manifold. The plurality of heat exchange tube segments include a fold forming a first tube bank and a second tune bank in substantially parallel relation to one another along at least a portion of a length of the plurality of heat exchange tube segments. The first tube bank and the second tube bank are configured for sequential flow there through of a first heat transfer fluid.

[0005] In addition to one or more of the features described above, or as an alternative, in further embodiments further comprising a bend formed in the first tube bank, the second tube bank, or a combination comprising at least one of the foregoing.

[0006] In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of heat exchange tube segments are microchannel tubes having a plurality of discrete flow channels formed therein. [0007] In addition to one or more of the features described above, or as an alternative, in further embodiments a plurality of fins extend from at least a portion of the heat exchange tube segments.

[0008] In addition to one or more of the features described above, or as an alternative, in further embodiments the heat exchanger is configured for a second heat transfer fluid to sequentially flow through the first tube bank followed by flow through the second tube bank.

[0009] In addition to one or more of the features described above, or as an alternative, in further embodiments the fluid is a high pressure refrigerant configured for use at pressures exceeding 750 psig.

[0010] In addition to one or more of the features described above, or as an alternative, in further embodiments the heat exchanger includes two folds defining three tube banks.

[0011] In addition to one or more of the features described above, or as an alternative, in further embodiments the second tube bank and the third tube bank are in substantially parallel relation along a portion of a flow path length of the first heat transfer fluid.

[0012] In addition to one or more of the features described above, or as an alternative, in further embodiments the flow path of the first heat transfer includes a plurality of passes relative to a second heat transfer fluid.

[0013] In addition to one or more of the features described above, or as an alternative, in further embodiments the tube segments further comprise a tube depth measured from a leading edge to a trailing edged of the tube segment and wherein the tube depth is less than 14 millimeters.

[0014] According to another embodiment, a method of manufacturing a heat exchanger is provided including forming a plurality of heat exchange tube segments and folding the plurality of heat exchange tube segments to define a first tube bank and a second tube bank wherein a first center line of the first tube bank and a second center line of the second tube bank are in substantially parallel relation.

[0015] In addition to one or more of the features described above, or as an alternative, in further embodiments, forming a bend in the plurality of heat exchanger tube segments. The bend has an angle other than 180° such that the heat exchanger has a non-linear configuration.

[0016] In addition to one or more of the features described above, or as an alternative, in further embodiments the folding of the plurality of heat exchange tube segments occurs about an axis arranged perpendicular to a longitudinal axis of the plurality of heat exchange tube segments. [0017] In addition to one or more of the features described above, or as an alternative, in further embodiments forming the plurality of heat exchange tube segments includes extruding the plurality of heat exchange tube segments.

[0018] In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of heat exchange tube segments are microchannel tubes having a plurality of discrete flow channels formed therein.

[0019] In addition to one or more of the features described above, or as an alternative, in further embodiments a plurality of fins extend from at least a portion of the heat exchange tube segments.

[0020] In addition to one or more of the features described above, or as an alternative, in further embodiments further comprising mounting a plurality of fins to at least a portion of the heat exchange tube segments.

[0021] In addition to one or more of the features described above, or as an alternative, in further embodiments attaching a first manifold to a first end of the plurality of heat exchange tube segments and attaching a second manifold to a second, opposite end of the plurality of heat exchange tube segments.

[0022] In addition to one or more of the features described above, or as an alternative, in further embodiments the first manifold and the second manifold are configured for use with a high pressure refrigerant exceeding 750 psig.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present subject matter 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 present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

[0024] FIG. 1 is a schematic diagram of an example of a vapor refrigeration cycle of a refrigeration system.

[0025] FIG. 2 is a side view of a microchannel heat exchanger prior to a bending operation.

[0026] FIG. 3 is a cross-sectional view of a tube segment of a microchannel heat exchanger.

[0027] FIG. 4 is a schematic top view of a folded microchannel heat exchanger having two tube banks.

[0028] FIG. 5 is a schematic top view of a microchannel heat exchanger. [0029] The detailed description explains the present disclosure, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION

[0030] Referring now to FIG. 1, a vapor compression refrigerant cycle 20 of an air conditioning or refrigeration system is schematically illustrated. Exemplary air conditioning or refrigeration systems include, but are not limited to, split, packaged, chiller, rooftop, supermarket, and transport refrigeration systems for example. A refrigerant R is configured to circulate through the vapor compression cycle 20 such that the refrigerant R absorbs heat when evaporated at a low temperature and pressure and releases heat when condensed at a higher temperature and pressure. Within this cycle 20, the refrigerant R flows in a counterclockwise direction as indicated by the arrow. The compressor 22 receives refrigerant vapor from the evaporator 24 and compresses it to a higher temperature and pressure, with the relatively hot vapor then passing to the condenser 26 where it is cooled and condensed to a liquid state by a heat exchange relationship with a cooling medium (not shown) such as air. The liquid refrigerant R then passes from the condenser 26 to an expansion device 28, wherein the refrigerant R is expanded to a low temperature two-phase liquid/vapor state as it passes to the evaporator 24. The low pressure vapor then returns to the compressor 22 where the cycle is repeated. It has to be understood that the refrigeration cycle 20 depicted in FIG. 1 is a simplistic representation of an HVAC&R system, and many enhancements and features known in the art may be included in the schematic. In particular, the heat pump refrigerant cycle may include a mechanism (not shown) for reversing the refrigerant flow direction throughout the refrigerant cycle (e.g., including a four way valve, a piping tee, a shutoff valve, a bi-directional valve, a three way valve, a reversible compressor, a separate reverse compressor, or a combination including at least one of the foregoing, and the like) to switch between the cooling and heating mode of operation for the environment to be conditioned.

[0031] Referring now to FIG. 2, an example of a heat exchanger 30 configured for use in the vapor compression system 20 is illustrated in more detail. The heat exchanger 30 may be used as either a condenser 24 or an evaporator 28 in the vapor compression system 20. The heat exchanger 30 includes at least a first manifold or header 32, a second manifold or header 34 spaced apart from the first manifold 32, and a plurality of tube segments 36 extending in a spaced, parallel relationship between and connecting the first manifold 32 and the second manifold 34. In the illustrated, non-limiting embodiments, the first header 32 and the second header 34 are oriented generally vertically and the heat exchange tube segments 36 extend generally horizontally between the two headers 32, 34. However, other configurations, such as where the first and second headers 32, 34 are arranged substantially horizontally are also within the scope of the invention.

[0032] FIG. 3 illustrates a cross-sectional view of a portion of the plurality of heat exchanger tube segments 36. The heat exchanger tube segments 36 may include any cross- sectional shape. For example, the cross sectional shape of the heat exchanger tube segments 36 can include circular, elliptical, polygonal having straight and/or curved sides, such as a rounded rectangular shape as shown in FIG. 3. The tube segments 36 can have a leading edge 38, a trailing edge 40, a first side 42, and a second, opposite side 44. The leading edge 38 of the heat exchange tube 36 is upstream from its respective trailing edge 40 with respect to the flow of a second heat transfer fluid A (e.g., air, nitrogen, and the like) through the heat exchanger 30. The respective leading and trailing edges of the tube segments 36 can be rounded, thereby providing a blunt leading edge 38 and a blunt trailing edge 40. However, it is to be understood that the respective leading and trailing edges of the tube segments 36 may be formed in other configurations (e.g., diverging, converging, elliptical, airfoil like, polygonal having straight or curved sides, and the like). The tube segment 36 can have any suitable tube depth T (FIG. 3) defined as the distance between the leading edge 38 and trailing edge 40. For example, the tube depth T can be less than 16 millimeters (mm), for example, less than 14 mm, or, 6 mm to 14 mm, or, 8 mm to 12 mm, or, 10 mm.

[0033] The heat exchanger tube segments 36 illustrated and described herein are intended as an example only and tube segments 36 having other constructions are within the scope of the disclosure. For example, the tube segments 36 may have a plurality of tube portions separated by a web as disclosed in Application Serial No. 14/351 ,235, filed September 25, 2012, and Application Serial No. 14/376,195, filed on January 29, 2013, the contents of both of which are incorporated by reference herein in its entirety.

[0034] A plurality of fins 50 may be mounted to a portion, such as the exterior for example, of the plurality of tube segments 36, and serve as a secondary heat transfer surface configured to transfer heat between a second heat transfer fluid (e.g., air, nitrogen, and the like) and a first heat transfer fluid (e.g., refrigerant, including low global warming potential (GWP) refrigerants such as C0₂, or other fluid flowing through the tube segments 36).

[0035] With reference now to FIGS. 4 and 5, each of the plurality of tube segments 36 of the heat exchanger 30 can include one or more folds 60. A fold 60 may be arranged at any location along a length, L, of the tube segments 36 (e.g., measured along an x-axis dimension corresponding to the longest dimension of the tube segment 36, as shown in FIG. 2). A fold 60 can be formed about an axis extending parallel to a manifold (e.g., the first manifold 32, the second manifold 34, or the like) and substantially perpendicular to the longitudinal axis of the tube segment 36 (along which the length of the tube segment 36 can be measured).

[0036] The fold 60 may be formed such that two portions of the heat exchange tube segment 36 adjacent to and on opposite sides of a respective fold 60 are arranged in substantially parallel relation. The term "substantially parallel" as used herein, can be defined as where an angle Θ, measured between two centerlines corresponding to each of the two elements described as in "substantially parallel" relation (see FIG. 5), is less than or equal to 5°, for example, less than or equal to 3°, or, less than or equal to 1°, or less than or equal to 0.5° (e.g., such as accounting for variations due to tooling tolerances, or manufacturing variations in a tube segment). As a result, the portions of a heat exchanger tube segment 36 on opposite sides of a respective fold 60 are generally arranged at an angle Θ between 175° and 185° relative to one another.

[0037] In one embodiment, the fold 60 is a ribbon fold wherein the tube segments 36 are partially twisted to achieve a substantially parallel orientation of the two portions on opposing sides of the fold 60 without causing the tube segment 36 to collapse. However, other types of folds are within the scope of the invention. Further, to achieve the desired fold, the tube segments 36 may be free of fins 50 at a selected portion 52 (see FIG. 2) within or surrounding the location of a fold 60.

[0038] Each fold 60 is configured to change the flow direction by a flow angle of about 180° (measured between the direction of flow through the interior passages of the tube segment 36 adjacent to and on opposite sides of the fold 60) such that the heat exchanger 30 has a multipass configuration relative to the direction of flow A of the second heat transfer fluid (e.g., air, nitrogen, and the like), e.g., where the second heat transfer fluid passes the first heat transfer fluid two or more times. The tube segments 36 on opposing sides of the fold 60 can form a plurality of tube banks, e.g., a first tube bank 80 and a second tube bank 82. The second tube bank 82 can be arranged downstream or behind the first tube bank 80 with respect to the direction of a flow A of the second heat transfer fluid (e.g., forming a two- pass configuration for the first heat transfer fluid).

[0039] As shown in FIG. 4, the heat exchanger 30 has a first tube bank 80 and a second tube bank 82 defined by the fold 60, with the second tube bank 82 being arranged in substantially parallel relation to a first tube bank 80. The heat exchanger 30 illustrated in FIG. 5, includes two folds 60 which form a first tube bank 80, a second tube bank 82, and a third tube bank 84. The heat exchanger 30 can have any number of folds 60, for example, 1 to 20 folds, or, 1 to 10 folds, or 1 to 5 folds, or, 1 to 3 folds, or 1 to 2 folds. The number of tube banks can correspond to the number of folds 60 as provided by the relation b=f+l, where b is the number of tube banks and f is the number of folds 60.

[0040] Alternatively, or in addition, the plurality of tube segments 36 can include a bend 70 having an angle other than 180° (relative to the direction of flow through a tube segment) such that at least one of the tube banks of the heat exchanger 30 has a non-linear configuration as measured along the flow direction through the interior flow passages of the tube segment 36. For example, the heat exchanger 30 can include a first bend 70a, imparting a first flow angle τΐ other than 180° on a fluid flowing through the tube segment 36, and a second bend 70b imparting a second flow angle y2 other than 180°. The first flow angle τΐ can be equal to the second flow angle τ2, or the two angles can be unequal. In an embodiment, the bend 70 can have an angle of less than 180°.

[0041] Similarly, a heat exchanger 30 having any number of bends 70, for example 1 to 20 bends, 1 to 10 bends, 1 to 5 bends, or 1 to 2 bends, is within the scope of the disclosure. As a result, heat exchangers 30 having any non-linear configuration are within the scope of the invention. The heat exchanger 30 can be configured for a counter flow relation, cross flow relation, or a combination including at least one of the foregoing of the two fluids exchanging heat in the heat exchanger.

[0042] One or more folds 60 and/or bends 70 can be used to build up the thickness of the heat exchanger 30 (relative to the flow of the second heat transfer fluid) which can allow for the manufacture of many different thicknesses without changing the basic tube segment design. In this way, the capacity of the heat exchanger 30 can be altered without altering the manufacturing tooling (e.g., extrusion equipment in the case of an extruded tube). For example, a heat exchanger 30 can comprise tube segments 36 having a tube depth of 10 mm and one or more folds 60which can correlate to the overall heat exchanger thickness, T (measured along the flow direction A through a portion of the heat exchanger 30), of T = 10 (f +1) + X millimeters, where f is the number of folds 70 and X is the distance of a gap between the tube banks.

[0043] To manufacture a heat exchanger 30 described herein, a plurality of heat exchange tube segments 36 having a length extending between an first inlet end and a second outlet end equal to a total length of the flow path are formed, for example via extrusion. The first manifold 32 is connected to the first end of each of the plurality of tube segments 36 and the second manifold 34 is connected to the second, opposite end of each of the plurality of tube segments 36. Each of the plurality of folds 60 and bends 70, is then formed in the tube segments 36 at various locations to achieve a heat exchanger 30 having a desired configuration and flow path.

[0044] Formation of a heat exchanger 30 as described herein provides the benefit that the same manufacturing equipment can be used to fabricate a heat exchanger 30 having any of a variety of configurations. Further, formation of a heat exchanger 30 as described herein eliminates the need for intermediate manifolds, thereby reducing complexity and cost. The overall size of the plurality of heat exchange tube segments 36 may also be decreased via extrusion. Because the first manifold and second manifold 32, 34 are configured to couple to the heat exchanger tube segments 36 of only one tube bank, the size of the manifolds 32, 34, may also be reduced. As a result, the heat exchanger 30 may provide the structural integrity necessary for use with high pressure refrigerants, for example such as carbon dioxide (C0₂) or ethane (C₂H₆). High pressure refrigerants can be operated in transcritical and/or supercritical systems where the refrigerant pressure within the system can be greater than 720 psig, for example, greater than 750 psig, or, greater than 1,100 psig, or, greater than 1,500 psig, or, from 750 psig to 2,000 psig. The nomenclature "psig" as used herein refers to gauge pressure measure in pounds per square inch relative to ambient pressure.

[0045] Embodiment 1: A heat exchanger comprising: a first manifold; a second manifold separated from the first manifold; and a plurality of heat exchange tube segments arranged in spaced parallel relationship and fluidly coupling the first manifold and the second manifold, the plurality of heat exchange tube segments including a fold forming a first tube bank and a second tube bank in substantially parallel relation to one another along at least a portion of a length of the plurality of heat exchange tube segments; wherein the first tube bank and the second tube bank are configured for sequential flow there through of a first heat transfer fluid.

[0046] Embodiment 2: The heat exchanger according to claim 1, further comprising a bend formed in the first tube bank, the second tube bank, or a combination comprising at least one of the foregoing.

[0047] Embodiment 3: The heat exchanger according to either claim 1 or claim 2, wherein the plurality of heat exchange tube segments are microchannel tubes having a plurality of discrete flow channels formed therein.

[0048] Embodiment 4: The heat exchanger according to any of the preceding claims, wherein a plurality of fins extend from at least a portion of the heat exchange tube segments. [0049] Embodiment 5: The heat exchanger according to any of the preceding claims, wherein the heat exchanger is configured for a second heat transfer fluid to sequentially flow through the first tube bank followed by flow through the second tube bank.

[0050] Embodiment 6: The heat exchanger according to any of the preceding claims, wherein the fluid is a high pressure refrigerant configured for use at pressures exceeding 750 psig.

[0051] Embodiment 7: The heat exchanger according to any of the proceeding claims, wherein the heat exchanger includes two folds defining three tube banks.

[0052] Embodiment 8: The heat exchanger according to claim 7, wherein the second tube bank and the third tube bank are in substantially parallel relation along a portion of a flow path length of the first heat transfer fluid.

[0053] Embodiment 9: The heat exchanger according to any of the proceeding claims, wherein the flow path of the first heat transfer includes a plurality of passes relative to a second heat transfer fluid.

[0054] Embodiment 10: The heat exchanger according to any of the proceeding claims, wherein the tube segments further comprise a tube depth measured from a leading edge to a trailing edged of the tube segment and wherein the tube depth is less than 14 millimeters.

[0055] Embodiment 11: A method of manufacturing a heat exchanger, comprising: forming a plurality of heat exchange tube segments; folding the plurality of heat exchanger tube segments to define a first tube bank and a second tube bank wherein a first center line of the first tube bank and a second center line of the second tube bank are in substantially parallel relation.

[0056] Embodiment 12: The method according to claim 12, forming a bend in the plurality of heat exchanger tube segments, the bend having an angle other than 180° such that the heat exchanger has a non-linear configuration.

[0057] Embodiment 13: The method according to either claim 11 or claim 12, wherein the folding of the plurality of heat exchange tube segments occurs about an axis arranged perpendicular to a longitudinal axis of the plurality of heat exchange tube segments.

[0058] Embodiment 14: The method according to any of the preceding claims, wherein forming the plurality of heat exchange tube segments includes extruding the plurality of heat exchange tube segments. [0059] Embodiment 15: The method according to any of the preceding claims, wherein the plurality of heat exchange tube segments are microchannel tubes having a plurality of discrete flow channels formed therein.

[0060] Embodiment 16: The method according to any of the preceding claims, wherein a plurality of fins extend from at least a portion of the heat exchange tube segments.

[0061] Embodiment 17: The method according to any of the preceding claims, further comprising: mounting a plurality of fins to at least a portion of the heat exchange tube segments.

[0062] Embodiment 18: The method according to any of the preceding claims, further comprising: attaching a first manifold to a first end of the plurality of heat exchange tube segments; and attaching a second manifold to a second, opposite end of the plurality of heat exchange tube segments.

[0063] Embodiment 19: The method according to claim 18, wherein the first manifold and the second manifold are configured for use with a high pressure refrigerant exceeding 750 psig.

[0064] While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure 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 present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include any number of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. The terms "a" and "an" and "the" herein do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

Claims

CLAIMS: What is claimed is:

1. A heat exchanger comprising:

a first manifold;

a second manifold separated from the first manifold; and

a plurality of heat exchange tube segments arranged in spaced parallel relationship and fluidly coupling the first manifold and the second manifold, the plurality of heat exchange tube segments including a fold forming a first tube bank and a second tube bank in substantially parallel relation to one another along at least a portion of a length of the plurality of heat exchange tube segments;

wherein the first tube bank and the second tube bank are configured for sequential flow there through of a first heat transfer fluid.

2. The heat exchanger according to claim 1, further comprising a bend formed in the first tube bank, the second tube bank, or a combination comprising at least one of the foregoing.

3. The heat exchanger according to either claim 1 or claim 2, wherein the plurality of heat exchange tube segments are microchannel tubes having a plurality of discrete flow channels formed therein.

4. The heat exchanger according to any of the preceding claims, wherein a plurality of fins extend from at least a portion of the heat exchange tube segments.

5. The heat exchanger according to any of the preceding claims, wherein the heat exchanger is configured for a second heat transfer fluid to sequentially flow through the first tube bank followed by flow through the second tube bank.

6. The heat exchanger according to any of the preceding claims, wherein the fluid is a high pressure refrigerant configured for use at pressures exceeding 750 psig.

7. The heat exchanger according to any of the proceeding claims, wherein the heat exchanger includes two folds defining three tube banks.

8. The heat exchanger according to claim 7, wherein the second tube bank and the third tube bank are in substantially parallel relation along a portion of a flow path length of the first heat transfer fluid.

9. The heat exchanger according to any of the proceeding claims, wherein the flow path of the first heat transfer includes a plurality of passes relative to a second heat transfer fluid.

10. The heat exchanger according to any of the proceeding claims, wherein the tube segments further comprise a tube depth measured from a leading edge to a trailing edged of the tube segment and wherein the tube depth is less than 14 millimeters.

11. A method of manufacturing a heat exchanger, comprising:

forming a plurality of heat exchange tube segments;

folding the plurality of heat exchanger tube segments to define a first tube bank and a second tube bank wherein a first center line of the first tube bank and a second center line of the second tube bank are in substantially parallel relation.

12. The method according to claim 11, forming a bend in the plurality of heat exchanger tube segments, the bend having an angle other than 180° such that the heat exchanger has a non-linear configuration.

13. The method according to either claim 11 or claim 12, wherein the folding of the plurality of heat exchange tube segments occurs about an axis arranged perpendicular to a longitudinal axis of the plurality of heat exchange tube segments.

14. The method according to any of the preceding claims, wherein forming the plurality of heat exchange tube segments includes extruding the plurality of heat exchange tube segments.

15. The method according to any of the preceding claims, wherein the plurality of heat exchange tube segments are microchannel tubes having a plurality of discrete flow channels formed therein.

16. The method according to any of the preceding claims, wherein a plurality of fins extend from at least a portion of the heat exchange tube segments.

17. The method according to any of the preceding claims, further comprising:

mounting a plurality of fins to at least a portion of the heat exchange tube segments.

18. The method according to any of the preceding claims, further comprising:

attaching a first manifold to a first end of the plurality of heat exchange tube segments; and

attaching a second manifold to a second, opposite end of the plurality of heat exchange tube segments.

19. The method according to claim 18, wherein the first manifold and the second manifold are configured for use with a high pressure refrigerant exceeding 750 psig.