Curved microtube heat exchanger

Abstract

A heat exchanger includes a frame and plates attached to the frame. The plates are spaced apart relative to each other and include apertures. The heat exchanger also includes microtubes that extend along the frame and through the apertures of the plates. The microtubes are curved along a length of the microtubes.

Description

CURVED MICROTUBE HEAT EXCHANGERCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 664,161, filed June 25, 2024, which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to a heat exchanger and more particularly to a microtube heat exchanger having a curved construction.BACKGROUND

[0003] Some conventional heat exchangers that employ microtubes can help promote heat exchange efficiency by passing a first fluid (e.g., coolant) through the microtubes as a second fluid (e.g., working fluid) is passed over the microtubes. The large quantity and small size of the microtubes promotes the exchange of heat between the first fluid and the second fluid.

[0004] Although microtube heat exchangers can provide relatively high heat exchange efficiency, conventional microtube heat exchangers are geometrically limited and spatially inefficient. In other words, conventional microtube heat exchangers fail to make efficient use of the spaces in which they are installed. For example, for some installation spaces, such as curved or non-planar spaces, known conventional microtube heat exchangers, which are noncurved or planar, do not conform to or fit well within such installation spaces.SUMMARY

[0005] The subject matter of the present application has been developed in response to the present state of the art, and in particular, in response to the shortcomings of traditional heat exchangers, including microtube heat exchangers, which have not yet been fully solved by currently available techniques. Accordingly, the subject matter of the present application has been developed to provide examples of a microtube heat exchanger, and associated systems and methods, which overcome at least some of the above-discussed shortcomings of prior art techniques.

[0006] According to a first example, disclosed herein is a heat exchanger that includes a frame and plates attached to the frame. The plates are spaced apart relative to each other and include apertures. The heat exchanger also includes microtubes that extend along the frame and through the apertures of the plates. The microtubes are curved along a length of the microtubes.

[0007] According to a second example, disclosed herein is a system that includes a structure having a curved surface that defines a curved space. The system also includes a heat exchanger that includes a frame, plates and microtubes. The frame has a curvature that substantially matches a curvature of the curved surface. The plates are attached to the frame, are spaced apart relative to each other, and include apertures. The microtubes extend along the frame and through the apertures of the plates. Moreover, the microtubes are curved along a length of the microtubes and have a curvature that matches the curvature of the curved surface.

[0008] According to a third example, disclosed herein is a method of making a heat exchanger. The method includes passing microtubes through apertures in plates when the microtubes are straight and the plates are parallel to each other. The method also includes reorienting each one of the plates relative to an adjacent one of the plates such that a portion of each one of the microtubes between adjacent ones of the plates is bent.

[0009] The described features, structures, advantages, and / or characteristics of the subject matter of the present disclosure may be combined in any suitable manner in one or more examples and / or implementations. In the following description, numerous specific details are provided to impart a thorough understanding of examples of the subject matter of the present disclosure. One skilled in the relevant art will recognize that the subject matter of the present disclosure may be practiced without one or more of the specific features, details, components, materials, and / or methods of a particular example or implementation. In other instances, additional features and advantages may be recognized in certain examples and / or implementations that may not be present in all examples or implementations. Further, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the subject matter of the present disclosure. The features and advantages of the subject matter of the present disclosure will become more fully apparent from the following description and appended claims, or may be learned by the practice of the subject matter as set forth hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order that the advantages of the subject matter may be more readily understood, a more particular description of the subject matter briefly described above will be rendered by reference to specific examples that are illustrated in the appended drawings. Understanding that these drawings, which are not necessarily drawn to scale, depict only certain examples of the subject matter and are not therefore to be considered to be limiting of its scope, thesubject matter will be described and explained with additional specificity and detail through the use of the drawings, in which:

[0011] Figure 1 is a perspective view of a heat exchanger, according to one or more examples of the present disclosure;

[0012] Figure 2 is a perspective view of the heat exchanger of Figure 1, shown from below the heat exchanger, according to one or more examples of the present disclosure;

[0013] Figure 3 is a side elevation view of the heat exchanger of Figure 1, according to one or more examples of the present disclosure;

[0014] Figure 4 is a top plan view of a heat exchanger, according to one or more examples of the present disclosure;

[0015] Figure 5 is a close-up perspective view of a portion of the heat exchanger of Figure 1, according to one or more examples of the present disclosure;

[0016] Figure 6 is a close-up perspective view of another portion of the heat exchanger of Figure 1, according to one or more examples of the present disclosure;

[0017] Figure 7 is a side elevation view of the heat exchanger of Figure 1 and a tubeinstallation tool coupled to the heat exchanger, according to one or more examples of the present disclosure;

[0018] Figure 8 is a close-up side elevation view of a portion of the heat exchanger of Figure 1 and the tube-installation tool of Figure 7, according to one or more examples of the present disclosure;

[0019] Figure 9 is a close-up perspective view of a portion of the heat exchanger of Figure 1 and the tube-installation tool of Figure 7, according to one or more examples of the present disclosure;

[0020] Figure 10A is a schematic side elevation view of a heat exchanger, shown in a first stage of manufacturing, according to one or more examples of the present disclosure;

[0021] Figure 10B is a schematic side elevation view of the heat exchanger of Figure 10A, shown in a second stage of manufacturing, according to one or more examples of the present disclosure;

[0022] Figure 10C is a schematic side elevation view of the heat exchanger of Figure 10A, shown in a third stage of manufacturing, according to one or more examples of the present disclosure;

[0023] Figure 11 is a perspective view of a heat exchanger, according to one or more examples of the present disclosure;

[0024] Figure 12 is a side elevation view of the heat exchanger of Figure 11, according to one or more examples of the present disclosure;

[0025] Figure 13 is a close-up perspective view of a portion of the heat exchanger of Figure 11, according to one or more examples of the present disclosure;

[0026] Figure 14 is a close-up perspective view of another portion of the heat exchanger of Figure 11, according to one or more examples of the present disclosure;

[0027] Figure 15 is a close-up perspective view of yet another portion of the heat exchanger of Figure 11, according to one or more examples of the present disclosure;

[0028] Figure 16A is a schematic side elevation view of a heat exchanger, shown in a first stage of manufacturing, according to one or more examples of the present disclosure; and

[0029] Figure 16B is a schematic side elevation view of the heat exchanger of Figure 16A, shown in a second stage of manufacturing, according to one or more examples of the present disclosure.DETAILED DESCRIPTION

[0030] Reference throughout this specification to "one example," "an example," or similar language means that a particular feature, structure, or characteristic described in connection with the example is included in at least one example of the present disclosure. Appearances of the phrases "in one example," "in an example," and similar language throughout this specification may, but do not necessarily, all refer to the same example. Similarly, the use of the term "implementation" means an implementation having a particular feature, structure, or characteristic described in connection with one or more examples of the present disclosure, however, absent an express correlation to indicate otherwise, an implementation may be associated with one or more examples.

[0031] Disclosed herein are examples of a microtube heat exchanger shaped to conform to the shape of the space within which the microtube heat exchanger is installed. More specifically, the microtube heat exchanger is curved (e.g., has microtubes that are curved) to match or correspond with the curvature of an installation space defined by a structure. The microtube heat exchanger, being curved in this manner, helps promote heat exchange efficiency, as well as spatial efficiency. Because the microtube heat exchanger is shaped to correspond with the shape of the installation space, the microtube heat exchanger makes better use of available installation space. Such improved spatial efficiency can free up space for additional parts or systems and contribute to an overall reduction in the size, profile, and / or mass of a structure in which the microtube heat exchanger is integrated.

[0032] Referring to Figures 1-6, some examples of a heat exchanger 100 are shown. The heat exchanger 100 includes an array of microtubes 114, as described in more detail below. Accordingly, the heat exchanger 100 can be considered a microtube heat exchanger. More specifically, because the microtubes 114 of the heat exchanger 100 are curved or non-linear (along an axial length of the microtubes 114), the heat exchanger 100 can be considered a curved microtube heat exchanger. Therefore, the terms "microtube heat exchanger" and "curved microtube heat exchanger" can be used interchangeably with the heat exchanger 100.

[0033] The heat exchanger 100 includes a frame 102 and plates 110, which cooperatively retain the microtubes 114 in one of any of various curved shapes. The frame 102, which is more rigid than the microtubes 114, includes a structure of outer beams 104 and inner beams 105. The outer beams 104 are parallel to each other and spaced-apart from each other across a width W of the frame 102 (see, e.g., Figure 4). Similarly, the inner beams 105 are parallel to each other and spaced-apart from each other across the width W of the frame 102. Each one of the inner beams 105 is co-planar and forms a set with a corresponding one of the outer beams 104. The plane, within which one set of the inner beams 105 and the outer beams 104 lies, is parallel to the plane, within which another set of the inner beams 105 and the outer beams 104 lies. In the illustrated example, the frame 102 includes two sets of outer beams 104 and inner beams 105.

[0034] The frame 102 additionally includes a plurality of cross-beams 106 each spanning a radial gap between the outer beam 104 and the inner beam 105, and coupling together the outer beam 104 and the inner beam 105, of a given set. In some examples, multiple crossbeams 106 couple together the outer beam 104 and the inner beam 105 of a given set. Accordingly, the frame 102 includes two matching and spaced-apart sides each including an outer beam 104, an inner beam 105, and multiple cross-beams 106. In certain examples, for a given side of the frame 102, the cross-beams 106 are equally spaced along the outer beam 104 and the inner beam 105 and / or each one of the cross-beams 106 is perpendicular to the outer beam 104 and the inner beam 105 at the locations to which the cross-beam 106 is coupled. These locations define plate-attachment locations at which a fastener 112, or other coupling device, couples or joins together the matching sides of the frame 102. More specifically, each one of multiple fasteners 112 of the frame 102 spans the width W of the frame 102 from one of the outer beam 104 or the inner beam 105 of one side of the frame 102 to a corresponding one of the outer beam 104 or the inner beam 105 of the opposite side of the frame 102. The fastener 112 can include a screw or bolt, which spans the width W, and a nut, which tightens the screw or bolt to the outer beam 104 and the inner beam 105. Asdescribed below, the portion of the fastener 112 that spans the width W provides an attachment structure for attaching a plate 110 to the frame 102.

[0035] The outer beam 104 and the inner beam 105 of the frame 102 are shaped (e.g., curved) according to a desired shape (e.g., curvature) of the array of microtubes 114. More specifically, the outer beam 104 and the inner beam 105 are shaped and the plate-attachment locations are located on the outer beam 104 and the inner beam 105 so that when the plates 110 are attached to the frame 102, the array of microtubes 114, passing at least partially through the plates 110, have the desired shape. Put another way, the plate-attachment locations defined by each one of the outer beams 104 and the inner beams 105 follow a path having a shape corresponding with the desired shape of the array of microtubes 114. In the illustrated example, the desired shape is a semi-circle so that the array of microtubes 114 have a semi-circular shape. Accordingly, the plate-attachment locations defined by each one of the outer beams 104 and the inner beams 105 follow a semi-circular shaped path. Likewise, in certain examples, each one of the outer beams 104 and the inner beams 105 has a semi-circular shape. The outer beams 104 and the inner beams 105 are concentric semicircles and thus have different radii of curvature. Referring to Figure 3, the inner beams 105 have a first radius of curvature rl and the outer beams 104 have a second radius of curvature r2 that is larger than the first radius of curvature rl . For comparison, the array of microtubes 114, which are concentric with the outer beams 104 and the inner beams 105, has a radius of curvature rt that is more than the first radius of curvature rl and less than the second radius of curvature r2.

[0036] Referring specifically to Figures 5 and 6, each one of the plates 110 includes a base plate 111 and an array of apertures 116 formed in the base plate 111. The arrangement or pattern of the array of apertures 116 corresponds with a desired arrangement or pattern of the array of microtubes 114. Each aperture 116 of the array of apertures 116 is a through- aperture, and sized and shaped to receive and retain a corresponding one of the microtubes 114 with at most a slip fit, but can include other shapes and fits to allow microtube displacement within an aperture 116 as desired or necessary to facilitate assembly or subsequent induced curvature. In other words, each one of the apertures 116 is configured to generally circumferentially enclose a microtube 114, limit lateral movement of the microtube when in the aperture 116, and allow some longitudinal movement of the microtube 114 axially along the aperture 116. In the illustrated example, the array of apertures 116 formed in each one of the plates 110 is arranged into spaced-apart rows. The spacing of the apertures 116 in a given row can be less than the spacing between adjacent rows of apertures 116. Theillustrated example includes an outer aperture row 116A, a middle aperture row 116B, and an inner aperture row 116C, which are parallel to each other. Moreover, the outer aperture row 116A, the middle aperture row 116B, and the inner aperture row 116C are parallel to the width W of the frame 102. In yet another example, the apertures are arranged in a staggered pattern.

[0037] Because each one of the microtubes 114 at least partially passes through a corresponding one of the apertures 116 of the outer aperture row 116A, the middle aperture row 116B, and the inner aperture row 116C, the microtubes 114 likewise are arranged into spaced-apart rows (e.g., outer microtube row 114A, middle microtube row 114B, and inner microtube row 114C). Accordingly, in the illustrated example, the spacing of the microtubes 114 in a given row of microtubes 114 can be less than the spacing between adjacent rows of microtubes 114. The outer microtube row 114A, the middle microtube row 114B, and the inner microtube row 114C are parallel to the width W of the frame 102. In some examples, the apertures 116 extends through a thickness of the base plate 111 such that the apertures 116 are parallel to the thickness of the base plate 111 and perpendicular to a plane defined by the base plates 111.

[0038] The size (e.g., diameter) of the microtubes 114 and the spacing of the microtubes 114 on a plate 110 can vary based on the application. According to some examples, a first ratio of the diameter of each one of the microtubes 110 to the spacing between the centers of the microtubes 110 of a given row of microtubes is approximately 1.25. In other examples, the first ratio is between, and inclusive of, 1.0 and 5.0. In yet further examples, the first ratio is between, and inclusive of, 1 and 20. In certain examples, a second ratio of the diameter of each one of the microtubes 110 to the spacing between the centers of the microtubes 114 of one row and those of the next adjacent row (i.e., spacing between rows of microtubes 114) is approximately 2.75. In yet other examples, the second ratio is between, and inclusive of, 2.0 and 10.0. According to further examples, the second ratio is between, and inclusive of, 1.01 and 20.

[0039] According to some examples, the microtubes 114 are cylindrical microtubes having circular-shaped cross-sections. However, in other examples, the microtubes 114 can have cross-sectional shapes other than circular. When the microtubes 114 are cylindrical microtubes, each one of the microtubes 114 can have an outer diameter of between, and inclusive of, 0.010 inches and 0.080 inches. In these examples, a wall thickness of each one of the microtubes 114 can be between, and inclusive of, 0.0005 inches and 0.010 inches. In some examples, an overall length of each one of the microtubes 114 can be between, andinclusive of, 0.5 inches and 240 inches. An overall width of the heat exchanger 100 can be between, and inclusive of, 0.5 inches and 240 inches. Also, in various examples, each row of microtubes 114 can have an overall length of between, and inclusive of, 0.012 inches and 24 inches. Of course, it is recognized that the above ranges are merely examples, and that other ranges are contemplated in view of the present disclosure.

[0040] The base plate 111 of each one of the plates 110 can be sized to span the width W of the frame 102 and span the gap between the outer beams 104 and the inner beams 105 of the frame 102. In some examples, the base plate 111 has a quadrilateral shape (e.g., square, rectangular, etc.). At outer and inner edges of the base plate 111, each one of the plates 110 can include a channel configured to receive and be retained by a corresponding one of the fasteners 112. Accordingly, the plates 110 are attached to the frame 102 via corresponding ones of the fasteners 112 passing through the channels. Because of the locations of the plateattachment locations, relative to the cross-beams 106, when the plates 110 are attached to the frame 102, each one of the plates 110 can be co-planar with a corresponding one of the crossbeam 106 on both sides of the frame 102. Moreover, because of the locations of the plateattachment locations, when the plates 110 are attached to the frame 102, the base plates 111 are perpendicular to the outer beams 104 and the inner beams 105 at the plate-attachment locations. Accordingly, the portion of the microtubes 114 within the apertures 116 of a base plate 111 are substantially perpendicular to the base plate 111, and concentric with the outer beams 104 and the inner beams 105 at the plate-attachment locations. The space between the frame and the array of microtubes 114 defines a fluid passageway 124 through which a second fluid can flow (see, e.g., Figure 3). As the second fluid flows through the fluid passageway 124 and over the microtubes 114, heat transfer between the second fluid and the first fluid flowing through the microtubes 114 can take place.

[0041] In the illustrated example, the plates 110 include a first end-plate 110A, a second end-plate HOB, and mid-plates 110C. The first end-plate 110A is positioned at a first end of the frame 102 and the second end-plate HOB is positioned at a second end of the frame 102. Because of the semi-circular shape of the frame 102, the first end-plate 110A and the second end-plate 110B are co-planar. A central one of the mid-plates 110C is located mid-way between, and oriented perpendicular to, the first end-plate 110A and the second end-plate 110B. Finally, an intermediate one of the mid-plates 110C is located mid-way between, and oriented at a minor angle (e.g., 45-degree angle) relative to, the first end-plate 110A and the central one of the mid-plates 110C, and another intermediate one of the mid-plates 110C is located mid-way between, and oriented at a 45-degree angle relative to, the second end-plate110B and the central one of the mid-plates 1 IOC. Accordingly, in some examples, the plates 110 are oriented relative to each other such that the base plate 111 of any one of the plates 110 is angled relative to the base plate 111 of any adjacent one of the plates 110.

[0042] The microtubes 114 and plates 110 can be made of any of various materials, such as metallic material (e.g., stainless steel, other steel alloys, aluminum, brass, and / or any other suitable metallic alloys), and / or polymeric materials.

[0043] Each one of the microtubes 114 extends from the first end-plate 110A, through the mid-plates 110C, to the second end-plate HOB. As presented above, the microtubes 114 follow a semi-circular shaped path along the frame 102. Accordingly, fluid flowing through the microtubes 114 also follows a semi-circular shaped path through the heat exchanger 100.

[0044] The curved nature of the heat exchanger 100 enables efficient utilization of curved spaces within a structure. For example, referring to Figure 3, the structure 120 includes an outer portion 122 A that defines an interior space 126, which can be an exterior space if desired. An interior surface of the outer portion 122 A may be curved, which defines a curvature of the interior space 126. The curvature of the frame 102 and microtubes 114 of the heat exchanger 100 can match the curvature of the interior surface of the outer portion 122 A, and thus match the curvature of the interior space 126. For example, the radius of curvature r2 of the outer beams 104 can be substantially equal to a radius of curvature of the interior surface of the outer portion 122A of the structure 120. Accordingly, underutilized or nonutilized portions of the interior space 126 are minimized. Further utilization of the curved interior space 126 is provided when an interior surface of an inner portion 122B of the structure 120 is curved and the curvature of the heat exchanger 100 matches curvature of the interior surface of the inner portion 122B. For example, the radius of curvature rl of the inner beams 105 can be substantially equal to a radius of curvature of the interior surface of the inner portion 122B of the structure 120.

[0045] Although the curvature of the heat exchanger 100 in the illustrated example is defined by a simple curve with a constant radius of curvature, in other examples, the curvature of the heat exchanger 100 can be defined by a complex curve with a variable radius of curvature and / or one or more points of inflection.

[0046] Referring to Figures 10 A- 10C, according to some examples, a method of making the heat exchanger 100 is schematically shown. As shown in Figure 10A, the method includes passing the microtubes 114 through the apertures 116 of the plates 110 when all the plates are parallel to each other and when the microtubes 114 are straight or non-curved. In some examples, the microtubes 114 can be permanently and non-movably fixed to the firstend-plate 110A, such as via any of various fixation methods, including, but not limited to, laser welding, brazing, induction welding, bonding, and / or the like. When fixed to the first end-plate 110A, the ends of the microtubes 114 can be co-planar. The overall length of the microtubes 114 are at least as long as the heat exchanger 100 when fully formed. Accordingly, when in the initial stage of manufacturing shown in Figure 10A, ends of the microtubes 114, opposite those ends fixed to the first end-plate 110A, extend through and beyond the second end-plate 11 OB. In some examples, in the initial stage, the ends of the microtubes 114, opposite those ends fixed to the first end-plate 110A, can be co-planar (i.e., all the microtubes 114 have the same length).

[0047] In a subsequent stage of the method, the central one of the mid-plates 110C, with the microtubes 114 still engaged within the apertures 116 of all the plates 110, is attached to the frame 102 at central ones of the plate-attachment locations, which can correspond with the location of central ones of the cross-beams 106. Attachment of the central one of the midplates 110C can include passing fasteners 112 through holes in the outer beam 104 and the inner beam 105 on one side of the frame 102, through the channels formed in the base plate 111 of the central one of the mid-plates 110C, and through holes in the outer beam 104 and the inner beam 105 on the other side of the frame 102, and securing the fasteners with nuts or other retention elements.

[0048] After the central one of the mid-plates 110C is secured to the frame 102, the intermediate ones of the mid-plates 110C can be moved and reoriented, relative to the central one of the mid-plates 110C, into a position adjacent corresponding intermediate ones of the plate-attachment locations. The intermediate ones of the plate-attachment locations can correspond with the location of intermediate ones of the cross-beams 106. In this position, the intermediate ones of the mid-plates 110C are then attached to the frame 102 at corresponding ones of the intermediate ones of the plate-attachment locations. Attachment of the intermediate ones of the mid-plates 110C can be executed in the same manner as the central one of the mid-plates 110C described above.

[0049] Referring to Figure 10B, as the intermediate ones of the mid-plates 110C are moved and reoriented as shown, the microtubes 114 are bent towards the intermediate ones of the plate-attachment locations so that the portions of the microtubes 114 between the central one of the mid-plates 110C and the intermediate ones of the mid-plates 110C become curved or non-linear. The portions of the microtubes 114 between the intermediate ones of the midplates 110C and the first end-plate 110A and second end-plate HOB, respectively, remain straight or non-curved. As the intermediate ones of the mid-plates 110C are moved andreoriented, the microtubes 114 experience some travel within the apertures 116 in the intermediate ones of the mid-plates 1 IOC. Moreover, because the radius of curvature of the microtubes 114 of the outer microtube row 114A is greater than the radius of curvature of the microtubes 114 of the middle microtube row 114B and the inner microtube row 114C, travel of the microtubes within the apertures 116 of the outer aperture row 116A is greater than that of the microtubes within the apertures 116 of the middle aperture row 116B and the inner aperture row 116C. Therefore, the ends of the microtubes 114 of the middle microtube row 114B and the inner microtube row 114C extend further from the second end-plate 1 IB than the ends of the microtubes 114 of the outer microtube row 114 A.

[0050] After the intermediate ones of the mid-plates 110C are attached to the frame 102, the first end-plate 110A and the second end-plate HOB can be moved and reoriented, relative to the intermediate ones of the mid-plates 110C, into a position adjacent corresponding end ones of the plate-attachment locations. The end ones of the plate-attachment locations can correspond with the location of end ones of the cross-beams 106. In this position, the first end-plate 110A and the second end-plate HOB are then attached to the frame 102 at corresponding ones of the end ones of the plate-attachment locations. Attachment of the first end-plate 110A and the second end-plate 110B can be executed in the same manner as the central one of the mid-plates 110C described above.

[0051] Referring to Figure 10C, as the first end-plate 110A and the second end-plate 110B are moved and reoriented as shown, the microtubes 114 are bent towards the end ones of the plate-attachment locations so that the portions of the microtubes 114 between the intermediate ones of the mid-plates 110C and the first end-plate 110A and the second endplate 110B, respectively, become curved or non-linear. Accordingly, in this stage of the method, all portions of the microtubes 114 are curved. As the first end-plate 110A and the second end-plate 110B are moved and reoriented, the microtubes 114 experience some travel within the apertures 116 in only the second end-plate 110B because the microtubes 114 are non-movably fixed to the first end-plate 110A. Moreover, for the same reasons presented above, travel of the microtubes within the apertures 116 of the outer aperture row 116A is greater than that of the microtubes within the apertures 116 of the middle aperture row 116B and the inner aperture row 116C. Therefore, the ends of the microtubes 114 of the middle microtube row 114B and the inner microtube row 114C still extend further from the second end-plate 110B than the ends of the microtubes 114 of the outer microtube row 114 A.

[0052] After the first end-plate 110A and the second end-plate 110B are attached to the frame 102, the excess portions of the microtubes 114 extending away from the second end-plate HOB can be trimmed and the ends of the microtubes 114 in the apertures of the second end-plate HOB can be fixed to the second end-plate 110B using any of various fixation methods, such as those listed above. The ends of the microtubes 114 can be trimmed to be flush with the surface of the second end-plate 11 OB or to extend the same distance from the second end-plate 110B. After fixing the microtubes 114 to the second end-plate 110B, the heat exchanger 100 is fully assembled and can be attached to a structure as desired.

[0053] Referring now to Figures 7-9, in some examples, a tube-installation tool 140 can be used to help maintain the position of the microtubes 114, relative to each other, as the microtubes 114 are bent during assembly of the heat exchanger 100, as described above. The tube-installation tool 140 includes a pair of fixtures 142 that are spaced-apart from each other. A desired spacing between the pair of fixtures 142 can be maintained via spacers 144 interposed between the fixtures 142. The spacers 144 are clamped between the fixtures 142 by corresponding fixture fasteners 148, which extend through one of the fixtures 142, through a corresponding one of the spacers 144, and through the other one of the fixtures 142. Tightening of the fixture fasteners 148, such as by rotating the fixture fasteners 148 relative to a nut, clamps the spacers 144 between the fixtures 142. Each one of the fixtures 142 includes one or more slots that hold retaining rods 146 in a column formation. The tubeinstallation tool 140 also includes a pair of set screws 150 where each set screw 150 is threadably engaged with a corresponding one of the fixtures 142. Rotation of the set screws 150 raises and lowers the set screws 150 relative to the retaining rods 146. The set screws 150 are located on the fixtures 142 in line with the retaining rods 146 so that the set screws 150 can be lowered into contact with an uppermost retaining rod and adjustment of position of the set screws 150 adjusts the pressure applied to the uppermost retaining rod, which, as described below, brings all retaining rods 146 in contact with the microtubes 114, and maintains prescribed spacing and fixing of microtubes in relation to the tube-attachment tool 140. Without the tube-attachment tool 140, in certain examples, the non-uniform friction force experienced on each of the tubes 114 within the apertures 116, as the mid-plates 110C are moved and reoriented, would cause unfixed microtubes to move at different rates relative to the mid-plates 110C, potentially causing some tubes to either generate a larger or smaller radius of curvature than desired or have a tube end condition (e.g., recessed below flush) not suitable for fixing to second end-plate 110B.

[0054] The tube-installation tool 140 helps maintain the position of the microtubes 114 relative to each other by applying a force to the microtubes 114 that counters the bending moment of the microtubes 114 as the microtubes are bent. In practice, the tube-installationtool 140 is temporarily coupled with the frame 102 and the microtubes 114 while the plates 110 are attached to the frame 102 and the microtubes 114 are bent. After the plates 110 are attached to the frame, the tube-installation tool 140 is removed from the frame 102 and the microtubes 114. The tube-installation tool 140 is coupled with the frame 102 and the microtubes 114 by positioning the fixtures 142 between the outer beams 104 and the inner beams 105 and on opposite sides of the central ones of the cross-beams 106 of the frame 102. The fixtures 142 are then secured together using the fixture fasteners 148. Referring to Figure 8, the retaining rods 146 are then inserted into the slots of the fixtures 142 so that the microtubes 114 of each one of the rows of microtubes is interposed between two adjacent ones of the retaining rods 146 of each column of retaining rods 146. The set screws 150 are then adjusted to apply pressure to the uppermost ones of the retaining rods 146 until the pressure is transferred from the uppermost retaining rods to the microtubes 114 of the outer microtube row 114 A, from the microtubes 114 of the outer microtube row 114A to the next adjacent retaining rods, and so forth, until pressure from the set screw 150 is transferred to the lowermost retaining rods. The microtubes 114 can then be bent by consecutively attaching the plates 110 to the frame 102 as described above. After all the plates 110 are attached to the frame 102 and the microtubes 114 are fully bent or curved, the set screws 150 can be adjusted to release the pressure between the retaining rods 146 and the microtubes 114. The tube-installation tool 140 can then be removed from the assembled heat exchanger 100.

[0055] Referring to Figures 11-15, alternative examples of a heat exchanger 200 are shown. The heat exchanger 200 includes some features that are similar to the features of the heat exchanger 100, with like numbers (i.e., 100-series vs. 200-series) referring to like features. For example, the heat exchanger 200 includes an array of microtubes 214 and plates 210, including a first end-plate 210A, a second end-plate 210B, and mid-plates 210C. The heat exchanger 200 also includes a frame 202 that includes outer beams 204 and inner beams 205. However, unlike the outer beams 104 and the inner beams 105 of the frame 102 of the heat exchanger 100, which do not deform under a force sufficient to deform the microtubes 114, the outer beams 204 and the inner beams 205 of the frame 202 do deform under a force sufficient to deform the microtubes 214. The plates 210 include apertures 216 arranged into an outer aperture row 216A, a middle aperture row 216B, and an inner aperture row 216C, so that the microtubes 214 are arranged into an outer microtube row 214A, a middle microtube row 214B, and an inner microtube row 214C.

[0056] In contrast to the heat exchanger 100, each one of the mid-plates 210C of the heat exchanger 200 includes guide nuts 212 each configured to engage a corresponding one of the outer beams 204 and the inner beams 205. Rotation of a guide nut 212 moves the guide nut 212 translationally along the beam to which it is engaged. Accordingly, the guide nuts 212 enable attachment of the mid-plates 210C to the outer beams 204 and the inner beams 205, and selective and independent translational movement of different portions of the mid-plates 210C along the outer beams 204 and the inner beams 205. In some examples, the first endplate 210A and the second end-plate 210B are non-movably fixed to respective ends of the outer beams 204 and the inner beams 205, via any of various coupling devices. Also, the heat exchanger 200 includes an electrical-connection plate 260, in some examples, which is shown situated between the second end-plate 210B and the next adjacent mid-plate 210C, but could be in other locations. The electrical-connection plate 260 includes apertures in the same arrangement as the apertures 116 of the plates 110. The microtubes 114 extend through the apertures 116. Accordingly, the electrical -connection plate 260 helps to retain the microtubes 114 in place during assembly of the heat exchanger 200. Additionally, the electricalconnection plate 260, which is made of an electrically conductive material, such as a metallic material, is electrically connected to a power source associated with a microtube trimming system. Electrical energy is transferred to the microtubes 114 via the electrical -connection plate 260. The microtube trimming system then utilizes electrification of the microtubes 114 to facilitate trimming of the excess portions of the microtubes 114. The electrical-connection manifold 260 can also be positioned, via guide nuts 212, to be non-perpendicular to the tubes 214 that enter the aperture 216 of electrical-connection manifold 260 as to bind or kink, or jam the tubes within aperture 216 to create a locking force similar as describe above with tube-spacing tool 140.

[0057] Referring to Figures 16A and 16B, according to some examples, a method of making the heat exchanger 200 is schematically shown. As shown in Figure 16A, the method includes passing the microtubes 214 through the apertures 216 of the plates 210 when all the plates are parallel to each other and when the microtubes 214 are straight or non-curved. In some examples, the microtubes 214 can be permanently and non-movably fixed to the first end-plate 210A, such as via any of various fixation methods, including, but not limited to, laser welding, brazing, induction welding, bonding, and / or the like. When fixed to the first end-plate 210A, the ends of the microtubes 214 can be co-planar. The overall length of the microtubes 214 are at least as long as the heat exchanger 200 when fully formed. Accordingly, when in the initial stage of manufacturing shown in Figure 16 A, ends of themicrotubes 214, opposite those ends fixed to the first end-plate 210A, extend through and beyond the second end-plate 21 OB. In some examples, in the initial stage, the ends of the microtubes 214, opposite those ends fixed to the first end-plate 210A, can be co-planar (i.e., all the microtubes 214 have the same length).

[0058] In a subsequent stage of the method, as shown in Figure 16B, the guide nuts 212, of a first one of the mid-plate 210C closest to the first end-plate 210A, engaged with the outer beams 204 are rotated in a first direction to move a first half of the mid-plate 210C away from the first end-plate 210A (as shown by directional arrow), and the guide nuts 212 of the same mid-plate 210C and engaged with the inner beams 205 are rotated in a second direction, opposite the first direction, to move the second half of the mid-plate 210C toward the first end-plate 210A (as shown by directional arrow). This rotation of the mid-plate 210C, while engaged with the outer beams 204 and the inner beams 205, causes the outer beams 204 and the inner beams 205, as well as the portion of the microtubes 214 between the first end-plate 210A and the mid-plate 210C, to bend. The opposing rotation of the guide nuts 212 can continue until a desired bend of this portion of the microtubes 214 is reached.

[0059] Similar opposing rotation of the guide nuts 212 of the other mid-plates 210C can be performed until additional portions of the microtubes 214 are bent to a desired bend. In this manner, the microtubes 214 of the heat exchanger 200 can be bent. It is recognized that the guide nuts 212 of the mid-plates 210C can be adjusted in any order to effectuate the bend of the microtubes 214.

[0060] As the mid-plates 210C are rotated, via opposing rotation of the guide nuts 212, the microtubes 214 experience some travel within the apertures 216 in the mid-plates 210C. Moreover, because the radius of curvature of the microtubes 214 of the outer microtube row 214A is greater than the radius of curvature of the microtubes 214 of the middle microtube row 214B and the inner microtube row 214C, travel of the microtubes within the apertures 216 of the outer aperture row 216A is greater than that of the microtubes within the apertures 216 of the middle aperture row 216B and the inner aperture row 216C. Therefore, the ends of the microtubes 214 of the middle microtube row 214B and the inner microtube row 214C extend further from the second end-plate 210B than the ends of the microtubes 214 of the outer microtube row 214 A.

[0061] After the microtubes 214 are sufficiently bent, the excess portions of the microtubes 214 extending away from the second end-plate 210B can be trimmed and the ends of the microtubes 214 in the apertures 216 of the second end-plate 210B can be fixed to the second end-plate 210B using any of various fixation methods, such as those listed above.After fixing the microtubes 214 to the second end-plate 210B, the heat exchanger 200 is fully assembled and can be attached to a structure as desired.

[0062] Although in the illustrated examples, the heat exchangers include three rows of spaced apart apertures and microtubes, in other examples, the heat exchangers can include more or less than three rows of apertures and microtubes, and each row of apertures and microtubes can include any quantity of apertures and microtubes as desired.

[0063] In view of the foregoing, the present disclosure includes an improved heat exchanger for use in a variety of applications, including aerospace systems. In some examples, the improved heat exchanger is used in an environmental control system (ECS), which can include occupant cooling / heating, avionics cooling, auxiliary electronics cooling, auxiliary equipment cooling such as pods, engine oil cooling, transmission oil cooling, and auxiliary power unit cooling sub-systems. The heat exchangers disclosed herein can be of any size and shape of which an array of microtubes is utilized as the method of transferring heat from one fluid to another. The heat exchangers of the present disclosure may be operated as or configured to be a cross-flow device, a parallel-flow device, or a counter-flow device. The heat exchangers disclosed herein can have an array of thousands of microtubes, if not more. The array of microtubes are coupled together to act as one structure or one component of a larger structure, such as an aircraft system. The microtubes of the heat exchangers disclosed herein can pass either a water-based or oil-based liquid, 2-phase refrigerant, or gas through the center of the microtubes, and the heat exchangers allow either a gas, or a water-based or oil-based liquid, to cross over the microtubes in cross-directional flow, parallel flow, or counter flow, depending on the application, to complete the heat exchange with the fluid flowing through the microtubes.

[0064] In certain examples, the heat exchanger disclosed herein can allow for improved heat exchange performance, particularly when used as part of an aircraft ECS system, than previously capable. The coolant fluid can be passed through a pump or boosting pump, and then through the microtubes of the heat exchanger, which improves the efficiency of the system. The coolant fluid then continues through to other heat producing components or equipment and returns to an expansion tank of the ECS system. The microtube heat exchanger systems of the present disclosure enable more compact and efficient heat exchange than existing ECS and heat exchange systems. In addition to increasing the efficiency of heat exchange, adding a microtube heat exchanger to a heat exchange system, such as an aircraft ECS, allows other components of the system to be more efficient. For example, the efficiency of the microtube heat exchanger in an aircraft ECS allows for less demand on the compressorand pump in the ECS. The decreased demand enables a reduction in the size and weight of these components, which advantageously allows for further size and weight reductions at the system level.

[0065] The heat exchangers disclosed herein can be used in a variety of systems in the aerospace industry. For example, in addition to ECS systems, the heat exchangers are also applicable to other systems of an aircraft, including roll-on equipment and weapons systems, especially direct energy weapons, aircraft pod systems. The present technology can also be applicable to an array of customers across aerospace applications and other industries.

[0066] As used herein, the term "liquid" is defined as a fluid in liquid form. It is also recognized that a fluid, as used herein, can include any of various fluids, other than liquids, such as gases or plasmas.

[0067] In the above description, certain terms may be used such as "up," "down," "upper," "lower," "horizontal," "vertical," "left," "right," "over," "under" and the like. These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. But, these terms are not intended to imply absolute relationships, positions, and / or orientations. For example, with respect to an object, an "upper" surface can become a "lower" surface simply by turning the object over. Nevertheless, it is still the same object. Further, the terms "including," "comprising," "having," and variations thereof mean "including but not limited to" unless expressly specified otherwise. An enumerated listing of items does not imply that any or all the items are mutually exclusive and / or mutually inclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also refer to "one or more" unless expressly specified otherwise. Further, the term "plurality" can be defined as "at least two." Moreover, unless otherwise noted, as defined herein a plurality of particular features does not necessarily mean every particular feature of an entire set or class of the particular features.

[0068] The term "about" or "substantially" or "approximately" in some embodiments, is defined to mean within + / -5% of a given value, however in additional embodiments any disclosure of "about" or "substantially" or "approximately" may be further narrowed and claimed to mean within + / - 4% of a given value, within + / - 3% of a given value, within + / - 2% of a given value, within + / - 1% of a given value, or the exact given value. Further, when at least two values of a variable are disclosed, such disclosure is specifically intended to include the range between the two values regardless of whether they are disclosed with respect to separate embodiments or examples, and specifically intended to include the range of at least the smaller of the two values and / or no more than the larger of the two values.Additionally, when at least three values of a variable are disclosed, such disclosure is specifically intended to include the range between any two of the values regardless of whether they are disclosed with respect to separate embodiments or examples, and specifically intended to include the range of at least the A value and / or no more than the B value, where A may be any of the disclosed values other than the largest disclosed value, and B may be any of the disclosed values other than the smallest disclosed value.

[0069] Additionally, instances in this specification where one element is "coupled" to another element can include direct and indirect coupling. Direct coupling can be defined as one element coupled to and in some contact with another element. Indirect coupling can be defined as coupling between two elements not in direct contact with each other, but having one or more additional elements between the coupled elements. Further, as used herein, securing one element to another element can include direct securing and indirect securing. Additionally, as used herein, "adjacent" does not necessarily denote contact. For example, one element can be adjacent to another element without being in contact with that element.

[0070] As used herein, the phrase "at least one of', when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, "at least one of means any combination of items or number of items may be used from the list, but not all the items in the list may be required. For example, "at least one of item A, item B, and item C" may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, "at least one of item A, item B, and item C" may mean, for example, without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

[0071] Unless otherwise indicated, the terms "first," "second," etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a "second" item does not require or preclude the existence of, e.g., a "first" or lower-numbered item, and / or, e.g., a "third" or higher-numbered item.

[0072] As used herein, a system, apparatus, structure, article, element, component, or hardware "configured to" perform a specified function is indeed capable of performing the specified function without any alteration, rather than merely having potential to perform the specified function after further modification. In other words, the system, apparatus, structure, article, element, component, or hardware "configured to" perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for thepurpose of performing the specified function. As used herein, "configured to" denotes existing characteristics of a system, apparatus, structure, article, element, component, or hardware which enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system, apparatus, structure, article, element, component, or hardware described as being "configured to" perform a particular function may additionally or alternatively be described as being "adapted to" and / or as being "operative to" perform that function.

[0073] The schematic flow chart diagram(s), if included herein, is generally set forth as a logical flow chart diagram. As such, the depicted order and labeled steps are indicative of one example of the presented method. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated method. Additionally, the format and symbols employed are provided to explain the logical steps of the method and are understood not to limit the scope of the method. Although various arrow types and line types may be employed in the flow chart diagrams, they are understood not to limit the scope of the corresponding method. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the method. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.

[0074] The present subject matter may be embodied in other specific forms without departing from its spirit or essential characteristics. The described examples are to be considered in all respects only as illustrative and not restrictive. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

[0075] Further aspects are provided by the subject matter of the following clauses:

[0076] A heat exchanger (100, 200), comprising: a frame (102, 202); a set of plates (110, 210) attached to the frame (102, 202), and each plate (110) of the set of plates (110, 210) including a set of apertures (116, 216); and a set of microtubes (114, 214) extending along the frame (102, 202) and through the sets of apertures (116, 216) among the set of plates (110, 210), wherein the microtubes (114, 214) are curved along a length of the set of microtubes (114, 214).

[0077] The heat exchanger (100, 200) of claim 1, wherein the frame (102, 202) is curved, and wherein a curvature of the frame (102, 202) matches a curvature of the curved length of the set of microtubes (114, 214).

[0078] The heat exchanger (100, 200) of claim 1, wherein the frame (102, 202) is more rigid than the set of microtubes (114, 214).

[0079] The heat exchanger (100, 200) of claim 1, wherein the frame (102, 202) is at least as flexible as the set of microtubes (114, 214).

[0080] The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (110, 114, 214) are semi-circular shaped.

[0081] The heat exchanger (100, 200) of claim 1, wherein the set of plates (110, 210) comprises a first end-plate (110A), a second end-plate (HOB), and at least one mid-plate (HOC) positioned between the first end-plate (110A) and the second end-plate (HOB).

[0082] The heat exchanger (100, 200) of claim 6, wherein the first end-plate (110A) is coplanar with the second end-plate (HOB).

[0083] The heat exchanger (100, 200) of claim 7, wherein the at least one mid-plate (HOC) is not co-planar or parallel with the first end-plate (110A).The heat exchanger (100, 200) of claim 8, wherein the at least one mid-plate (110C) is orthogonal to the first end-plate (110A).

[0084] The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (114, 214) is perpendicular to each plate (110, 210) of the set of plates (110, 210) at the set of apertures (116, 216) where the set of microtubes (114, 214) pass through each plate (110, 210) of the set of plates (110, 210).

[0085] The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (114, 214) are non-perpendicular to at least one plate (110, 210) of the set of plates (110, 210) at a location away from the set of plates (110, 210).

[0086] The heat exchanger (100, 200) of claim 1, further comprising an electricalconnection plate (260) electrically coupled to the set of microtubes (114, 214).

[0087] The heat exchanger (100, 200) of claim 12, wherein the electrical-connection plate (260) comprises a set of electrical apertures (116, 216), and wherein the set of microtubes (114, 214) passes through the set of electrical apertures (116, 216).

[0088] The heat exchanger (100, 200) of claim 1, further comprising a tube-spacing tool (140) arranged among the set of microtubes (114, 214).

[0089] The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (114, 214) are arranged into rows of microtubes (114, 214), and wherein the rows are curved between the set of plates (110, 210).

[0090] A method of forming a heat exchanger (100, 200), the method comprising: positioning a set of microtubes (114, 214) through a set of apertures (116, 216) in a set ofplates (110, 210), wherein the microtubes (114, 214) are oriented in a straight arrangement, and wherein the set of plates (110, 210) are parallel to each other; and reorienting at least one plate (110, 210) of the set of plates (110, 210) relative to an adjacent plate (110, 210) of the set of plates (110, 210) such that a portion of at least one microtube (114, 214) of the set of microtubes (114, 214) between adjacent plates (110, 210) of the set of plates (110, 210) is bent or curved.

[0091] The method of claim 16, further comprising securing the set of plates (110, 210) to a frame (102, 202).

[0092] The method of claim 16, further comprising spacing some microtubes (114, 214) of the set of microtubes (114, 214) from at least some other microtubes (114, 214) of the set of microtubes (114, 214) with a tube-spacing tool (140).

[0093] The method of claim 16, further comprising electrically coupling the set of microtubes (114, 214) to an electrical supply with an electrical-connection plate (260).

[0094] The method of claim 19, wherein the set of microtubes (114, 214) are positioned through a set of electrical apertures (116, 216) in the electrical-connection plate (260).

Claims

CLAIMSWhat is claimed is:

1. A heat exchanger (100, 200), comprising: a frame (102, 202); a set of plates (110, 210) attached to the frame (102, 202), and each plate (110) of the set of plates (110, 210) including a set of apertures (116, 216); and a set of microtubes (114, 214) extending along the frame (102, 202) and through the sets of apertures (116, 216) among the set of plates (110, 210), wherein the microtubes (114, 214) are curved along a length of the set of microtubes (114, 214).

2. The heat exchanger (100, 200) of claim 1, wherein the frame (102, 202) is curved, and wherein a curvature of the frame (102, 202) matches a curvature of the curved length of the set of microtubes (114, 214).

3. The heat exchanger (100, 200) of claim 1, wherein the frame (102, 202) is more rigid than the set of microtubes (114, 214).

4. The heat exchanger (100, 200) of claim 1, wherein the frame (102, 202) is at least as flexible as the set of microtubes (114, 214).

5. The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (110, 114, 214) are semi-circular shaped.

6. The heat exchanger (100, 200) of claim 1, wherein the set of plates (110, 210) comprises a first end-plate (110A), a second end-plate (HOB), and at least one mid-plate (HOC) positioned between the first end-plate (110A) and the second end-plate (HOB).

7. The heat exchanger (100, 200) of claim 6, wherein the first end-plate (110A) is coplanar with the second end-plate (HOB).

8. The heat exchanger (100, 200) of claim 7, wherein the at least one mid-plate (110C) is not co-planar or parallel with the first end-plate (110A).

9. The heat exchanger (100, 200) of claim 8, wherein the at least one mid-plate (110C) is orthogonal to the first end-plate (110A).

10. The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (114, 214) is perpendicular to each plate (110, 210) of the set of plates (110, 210) at the set of apertures(116, 216) where the set of microtubes (114, 214) pass through each plate (110, 210) of the set of plates (110, 210).

11. The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (114, 214) are non-perpendicular to at least one plate (110, 210) of the set of plates (110, 210) at a location away from the set of plates (110, 210).

12. The heat exchanger (100, 200) of claim 1, further comprising an electrical-connection plate (260) electrically coupled to the set of microtubes (114, 214).

13. The heat exchanger (100, 200) of claim 12, wherein the electrical-connection plate (260) comprises a set of electrical apertures (116, 216), and wherein the set of microtubes (114, 214) passes through the set of electrical apertures (116, 216).

14. The heat exchanger (100, 200) of claim 1, further comprising a tube-spacing tool (140) arranged among the set of microtubes (114, 214).

15. The heat exchanger (100, 200) of claim 1, wherein the set of microtubes (114, 214) are arranged into rows of microtubes (114, 214), and wherein the rows are curved between the set of plates (110, 210).

16. A method of forming a heat exchanger (100, 200), the method comprising: positioning a set of microtubes (114, 214) through a set of apertures (116, 216) in a set of plates (110, 210), wherein the microtubes (114, 214) are oriented in a straight arrangement, and wherein the set of plates (110, 210) are parallel to each other; and reorienting at least one plate (110, 210) of the set of plates (110, 210) relative to an adjacent plate (110, 210) of the set of plates (110, 210) such that a portion of at least one microtube (114, 214) of the set of microtubes (114, 214) between adjacent plates (110, 210) of the set of plates (110, 210) is bent or curved.

17. The method of claim 16, further comprising securing the set of plates (110, 210) to a frame (102, 202).

18. The method of claim 16, further comprising spacing some microtubes (114, 214) of the set of microtubes (114, 214) from at least some other microtubes (114, 214) of the set of microtubes (114, 214) with a tube-spacing tool (140).

19. The method of claim 16, further comprising electrically coupling the set of microtubes (114, 214) to an electrical supply with an electrical-connection plate (260).

20. The method of claim 19, wherein the set of microtubes (114, 214) are positioned through a set of electrical apertures (116, 216) in the electrical-connection plate (260).

Images