MICROCHANNEL BONDED PANEL AND HEAT EXCHANGE SYSTEM

Abstract

A micro-channeled panel heat exchange system is disclosed. An example embodiment includes: one or more micro-channeled panels, each micro-channeled panel having micro-channels fabricated internally within each micro-channeled panel for transfer of a working fluid, each of the one or more micro-channeled panels having a cover layer diffusion bonded or brazed to the micro-channels, each of the one or more micro-channeled panels having a thickness of no more than two millimeters, each of the one or more micro-channeled panels being twisted into a non-orthogonal shape; and one or more manifolds coupled to the one or more micro-channeled panels to circulate the working fluid through the micro-channels within each micro-channeled panel.

Description

COPYRIGHT

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the disclosure provided herein and to the drawings that form a part of this document: Copyright 2022-2024, VPE Thermal LLC, a subsidiary of Vacuum Process Engineering, Inc.; All Rights Reserved.

TECHNICAL FIELD

The disclosed subject matter relates to the field of heat exchangers, heat exchanging devices, heat exchanging panels, and methods of making a heat exchanging device or panel, and in particular, to a micro-channeled panel heat exchange system.

BACKGROUND

Often, an operating machine or electronic component or an industrial process system or aerospace application generates waste heat in the course of its normal operation. If this waste heat is not removed, degraded performance or damage to the system may result. Frequently, the operating temperature of a system needs to be precisely maintained in order to obtain optimal performance. For example, it is often desirable to cool the sensors used in thermal imaging cameras to improve the sensitivity of the imager. Further, analytical instruments may require that the sample to be analyzed be presented to the instrument at a precisely controlled temperature. Additionally, heat exchangers are important in industrial process heat recovery systems and concentrating solar thermal power (CSP) systems.

Heat exchangers permit heat to be removed or added to the sample as may be desired. A common type of heat exchanger is referred to as a “heat sink.” A heat sink typically transfers heat between a solid object and some fluid media, which may be a liquid, air or other gasses. Computer microprocessors frequently employ heat sinks to draw heat from the processor to the surrounding air, thereby cooling the microprocessor. Fins are often provided to increase the surface area of the heat sink to the air thereby increasing the efficiency of the heat sink. Such a heat sink could also comprise a closed fluid system. For example, a recirculating liquid coolant might be used to transfer heat from that portion of the heat sink in contact with the heat-generating device to a remotely located radiator. The heat sink could be of a single or a two-phase fluid design.

Another type of heat exchanger employs at least two fluids. In this type of heat exchanger, heat is transferred from a first fluid to a second fluid without direct contact between the fluids. For example, a fluid-to-fluid heat exchanger for a blood processing machine may employ heated water to warm the blood to the proper temperature. The blood circulating path is completely separate from that of the water circulating path and dilution or contamination of the blood is thus avoided. Other types of heat exchangers include those designed to recover waste heat from systems that produce excess heat, for example, a passenger compartment heater that derives heat from an automobile engine. Regardless of the type of heat exchanger, it is desirable to obtain a high degree of heat transfer efficiency.

The basic function of a heat exchanger is to convey heat from one location to another. While some heat exchangers are relatively simple, such as that of a cast aluminum heat sink for a semiconductor, others are quite complex and require a variety of sophisticated manufacturing processes. For example, some manufacturing processes use diffusion bonding and/or additive manufacturing to combine layers of a heat exchanger. Other manufacturing processes can use brazing to combine a stack of planar members to produce heat exchangers. These processes permit the construction of very intricate internal structures. In the case of a heat exchanger or chemical reactor produced by these means, it is necessary to provide ports so the heat exchanging fluids or reactant chemicals can be hermetically ported into and out of the device proper. However, conventional systems and fabrication processes have been unable to efficiently manufacture these structures.

SUMMARY

There is disclosed herein various example embodiments of a micro-channeled panel heat exchange system. Working fluids may be passed within the panel via the internally integrated micro-channels. As used herein, the term “fluid” includes air, gas, liquid, or plasmas, which can be used as working fluids within example embodiments of the heat exchanger as described herein. In example embodiments, a heat exchanger comprises an etched sheet, plate, or panel (e.g., the micro-channeled layer), which is etched (e.g., via chemicals, lasers, or the like) with micro-channels to carry a working fluid (e.g., carbon dioxide, helium, water, hydrogen, molten salt, liquid metals, supercritical carbon dioxide (sCO2), or the like) within the heat exchanger. The microchannel layer can also be manufactured using an additive process of adding layers of fluid passages. A cover sheet, plate, or panel (e.g., the cover layer) is diffusion bonded, brazed or welded to the micro-channeled layer in an assembly to form the micro-channeled panel heat exchange system. The micro-channeled panel heat exchange system can then be combined with a manifold to circulate the working fluid through the micro-channels of the heat exchange system. The micro-channeled panels of the example embodiments disclosed herein can be fabricated thinly enough or flexibly enough to be formed (e.g., rolled) into various shapes and geometries allowing variously shaped micro-channel bonded panels to be used for recovering heat from any industrial process including steel refinery or furnace applications, aerospace applications, or other use cases. The various example embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which:

FIG. 1 illustrates an example embodiment of a micro-channeled panel heat exchange system in a perspective view;

FIG. 2 illustrates an example embodiment of the various layers forming a micro-channeled panel heat exchange system in a side view;

FIGS. 3 through 7 illustrate a micro-channeled panel heat exchange system including one or more manifolds, wherein the micro-channeled panel heat exchange system can be fabricated and assembled in various shapes and geometries for a variety of applications or use cases;

FIGS. 8 through 12 illustrate various example embodiments of micro-channeled panels, which can be fabricated and assembled in various shapes and geometries for a variety of applications or use cases; and

FIG. 13 is a flow diagram illustrating an example embodiment of a method for fabricating a micro-channeled panel heat exchange system as described herein.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which are shown, by way of illustration, specific embodiments in which the disclosed subject matter can be practiced. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the disclosed subject matter.

In various example embodiments disclosed and illustrated herein, a micro-channeled panel heat exchange system is described. In example embodiments, a heat exchanger comprises an etched sheet, plate, or panel (e.g., the micro-channeled layer), which is etched (e.g., via chemicals, lasers, or the like) with micro-channels to carry a working fluid (e.g., carbon dioxide, helium, water, hydrogen, molten salt, liquid metals, supercritical carbon dioxide (sCO2), or the like) within the heat exchanger. A cover sheet, plate, or panel (e.g., the cover layer) is diffusion bonded, brazed or welded to the micro-channeled layer in an assembly to form the micro-channeled panel heat exchange system. The microchannel plate layer can also be fabricated using additive manufacturing methods. The micro-channeled panel heat exchange system can include one or more manifolds to circulate the working fluid through the micro-channels of the heat exchange system.

Referring to FIG. 1, an example embodiment of a micro-channeled panel heat exchange system 100 in a perspective view is illustrated. In the example embodiment shown, a heat exchanger 100 comprises a set of micro-channeled sheets, plates, or panels 130 forming the micro-channeled panel heat exchange system 100. The micro-channeled panel heat exchange system 100 can include a high-efficiency manifold or set of manifolds 140 to circulate the working fluid through the micro-channels of the heat exchange system. The micro-channeled panel heat exchange system of an example embodiment is an innovative, compact heat exchanger for use with a working fluid, such as carbon dioxide, helium, water, hydrogen, molten salt, liquid metals, supercritical carbon dioxide (sCO2), or the like. In fact, any working fluid that is high pressure and potentially corrosive (where the containment requires a higher grade material) and/or where small micro-channels are used for better containment of high pressure can benefit from the construction of the micro-channeled panel heat exchange system as described herein. To reduce manufacturing costs, the micro-channeled panel heat exchange system internal components can be assembled with a combination of brazed, diffusion-bonded, or welded elements, enabling optimal material selection for each application.

In example embodiments, the micro-channeled plates sheets, or panels and the cover layers can be fabricated from high nickel alloys such as Inconel 740H and Inconel 617, which can achieve temperatures ˜900 C and pressures ˜260 bar. This fabrication paired with a high emissivity coating applied to bonded plate surfaces, enhance heat transfer. Heat exchange system geometries and flow patterns can be optimized to provide maximum heat transfer efficiency between hot and cold surfaces or streams. Additionally, using micro flow channels allows for a large interface surface area between surfaces or streams while maintaining an overall compact design.

The micro-channeled panels of the example embodiments disclosed herein can be fabricated thinly enough or flexibly enough to be formed (e.g., rolled or twisted) into various shapes and geometries allowing variously shaped micro-channel bonded panels to be used for recovering or redistributing heat from any industrial process including steel refinery or furnace applications, aerospace applications, or other use cases. In particular example embodiments, the micro-channeled panels can be fabricated with a thickness of no more than two millimeters (2 mm.). This ultra-thin micro-channeled panel, with the fluid-carrying channels fabricated therein, enables the panel to be formed (e.g., rolled or twisted) into various shapes and geometries. The applications or use cases of the example embodiments can include high flux solar receivers, industrial waste heat recovery in high temperature steel and aluminum processes, aerospace gas turbine air/fuel heat exchangers, and the like. The micro-channeled panels of the example embodiments can be configured to have a curved plate covering a higher view factor from a heat flux source. Some example applications or use cases for the micro-channel bonded panels of the example embodiments disclosed herein are described and illustrated herein.

Referring now to FIG. 2, an example embodiment of the various layers forming the micro-channeled panel heat exchange system in a side view is illustrated. The example embodiment uses etched sheets, plates, or panels (micro-channel layer) 220 for the working fluid side. As shown, a micro-channeled layer 220 is created to provide micro-channels for the flow of the working fluid stream. The micro-channeled layer 220 for the working fluid stream can be fabricated using a chemical subtractive process, built using an additive process, or cut to pre-determined dimensions using a laser or laser-based process. Depending on the fabrication process used, both a top and bottom cover sheet may be required. In other embodiments, the micro-channeled layer 220 can be fabricated using: electrochemical machining (ECM), electrical discharge machining (EDM), computer numerical controlled (CNC) machining, mechanical machining, grinding, or the like. As described in more detail below, the pattern etched on the micro-channeled layer 220 can employ various flow configurations, including counter-flow and multi-pass arrangements, to increase heat transfer while maintaining a compact design.

Referring still to FIG. 2, a blank cover plate, sheet, or panel (cover layer) 210 can be placed over the micro-channeled layer 220 to close the micro channels within the assembly. The blank cover layer 210 can be diffusion bonded or brazed to the micro-channeled layer 220 to create a diffusion bonded or brazed micro-channeled panel assembly 230 having broad and compact surface area for better heat transfer between the blank cover layer 210 and the micro-channeled layer 220. In various example embodiments, the material from which the micro-channeled plate 220 is fabricated can include: stainless steel alloys, SS300 series, titanium, nickel alloys, ferretics, or carbon steel.

The micro-channeled panel heat exchange system 100 can be assembled with a combination of brazed, diffusion-bonded, or welded elements. The use of diffusion bonding or brazing for the diffusion bonded or brazed micro-channeled panel assembly 230 creates a beneficial and thermally efficient interface and surface for thermal transfer between the blank cover layer 210 and the micro-channeled layer 220. The use of brazing, diffusion-bonding, or welding for the micro-channeled panels enables the fabrication of micro-channeled panels with flexibility for enabling various shapes and geometries.

Referring now to FIGS. 1 and 3 through 7, the micro-channeled panel heat exchange system 100 including one or more manifolds 140 is illustrated, wherein the micro-channeled panel heat exchange system 100 can be fabricated and assembled in various shapes and geometries for a variety of applications or use cases. For example, a high flux heater (e.g., see FIG. 1) can be fabricated using the micro-channeled panels or plates 130 disclosed herein. The micro-channeled panels or plates 130 can be radially arrayed to heat fluid within the channels from surrounding heating elements. External or internal small manifolds 140 can distribute flows to and from the micro-channels within the panels or plates 130 to increase the fluid side heat transfer coefficient and reach higher heat flux to provide better mechanical integrity. The thin pressure boundary offered by these micro-channeled bonded plates 130 provide higher wall conductance.

Referring now to FIGS. 8 through 11, various example embodiments of micro-channeled panels 130 can be fabricated and assembled in various shapes and geometries for a variety of applications or use cases. For example, the micro-channeled panels or plates 130 can be radially arrayed to heat fluid within the channels from surrounding heating elements. The thin pressure boundary offered by these micro-channeled bonded plates provide higher wall conductance. FIG. 8 illustrates an example embodiment showing a finned micro-channel plate 130 after a bending process. FIG. 9 illustrates an example embodiment showing a twisted micro-channel plate 130 configured in a shell and plate arrangement. FIG. 10 illustrates an example embodiment showing a twisted micro-channel plate 130 configured in a shell and plate arrangement with manifold options. FIG. 11 illustrates an example embodiment showing a rolled micro-channel plate 130 configured in a concentric array arrangement. FIG. 12 illustrates an example embodiment showing an insertable heat exchanger apparatus for installation in an existing exhaust pipe for waste heat recovery in, for example, a high temperature furnace exhaust. It will be apparent to one of ordinary skill in the art in view of the disclosure herein that a variety of other shapes and geometries can be fabricated using the micro-channel plates 130 described herein, thereby achieving implementation of a micro-channeled panel heat exchange system in a variety of shapes, geometries, and configurations.

Referring again to FIG. 10, the diagram illustrates an application of the example embodiment showing a twisted micro-channel plate 130 configured in a shell and plate arrangement. This example embodiment can be used, for example, as an exhaust gas conduit to vent hot exhaust gas from, for example, a steel refinery furnace. Embodiments can also be configured as inserts into existing furnace exhaust pipes or conduits. In these applications, it is important to not restrict the flow of exhaust gas through the conduit; because, such exhaust gas interference may undesirably increase back pressure in the conduit. Additionally, the example embodiments provide an apparatus for waste heat recovery using high temperature furnace exhaust. As the high temperature furnace exhaust gas flows through the spiraled configuration of the twisted micro-channel plates 130, the outside surfaces of the micro-channel plates 130 heat up. This heat is then transferred into the working fluid circulating within the micro-channel plates 130. The heated working fluid can be collected via a manifold and transferred to other systems (not shown) which can use heated working fluid as a source of power or heat. The transfer of heat from the outside surfaces of the micro-channel plates 130 into the working fluid also serves to reduce the temperature of the outside surfaces of the micro-channel plates 130. As a result, the materials used to fabricate the outside surfaces of the micro-channel plates 130 can be less expensive materials that do not need to withstand excessive levels of heat. The spiraled configuration of the twisted micro-channel plates 130 enables the high temperature furnace exhaust to have a high degree of contact with the outside surfaces of the micro-channel plates 130. The radius of the turns of the spiral, the quantity of turns of the spiral, the length of the spiral, and the quantity of the micro-channel plates 130 can be varied to achieve a high degree of contact by the high temperature furnace exhaust with the spiral of the micro-channel plates 130 without creating exhaust gas interference undesirably increasing back pressure in the conduit. Additionally, heat transfer enhancing features (e.g., bumps, fins, roughness, etc.) can be added to the surface of the micro-channel plates 130 to enhance the transfer of heat from the high temperature furnace exhaust to the spiral surfaces of the micro-channel plates 130. In particular example embodiments, the micro-channel plates 130 can be fabricated with a thickness of no more than two millimeters (2 mm.). This ultra-thin micro-channeled plate 130, with the fluid-carrying channels fabricated therein, enables the micro-channeled plate 130 to be formed (e.g., rolled or twisted) into various shapes and geometries, including non-orthogonal shapes, such as the spiral shape shown in FIG. 10.

Referring again to FIG. 12, the diagram illustrates an example embodiment showing an insertable heat exchanger apparatus 1201 for installation in an existing exhaust pipe for waste heat recovery in, for example, a high temperature furnace exhaust system. Such high temperature furnace exhaust systems are often employed in steel refineries and cement plants. As shown in FIG. 12, the heat exchanger apparatus 1201 includes a spiraled configuration of the twisted micro-channel plates 130. As high temperature furnace exhaust gas flows through the spiraled configuration of the twisted micro-channel plates 130, the outside surfaces of the micro-channel plates 130 heat up. This heat is then transferred into the working fluid circulating within the micro-channel plates 130. The heated working fluid can be collected via manifold 140 and transferred to other systems. Heat transfer enhancing features (e.g., bumps, fins, roughness, etc.) can be added to the surface of the micro-channel plates 130 to enhance the transfer of heat from the high temperature furnace exhaust to the spiral surfaces of the micro-channel plates 130. In particular example embodiments, the micro-channel plates 130 can be fabricated with a thickness of no more than two millimeters (2 mm.). This ultra-thin micro-channeled plate 130, with the fluid-carrying channels fabricated therein, enables the micro-channeled plate 130 to be formed (e.g., rolled or twisted) into various shapes and geometries, including non-orthogonal shapes, such as the spiral shape shown in FIG. 12.

FIG. 13 is a flow diagram illustrating an example embodiment of a method for fabricating a micro-channeled panel heat exchange system as described herein. The method 1000 of an example embodiment is configured to: fabricate one or more micro-channeled panels, each micro-channeled panel having micro-channels fabricated internally within each micro-channeled panel for transfer of a working fluid, each of the one or more micro-channeled panels having a cover layer diffusion bonded or brazed to the micro-channels, each of the one or more micro-channeled panels having a thickness of no more than two millimeters (processing block 1010); twist the one or more micro-channeled panels into a non-orthogonal shape (processing block 1020); couple one or more manifolds to each of the one or more micro-channeled panels to circulate the working fluid through the micro-channels within each micro-channeled panel (processing block 1030), and enable passage of heated exhaust gas across surfaces of the one or more micro-channeled panels (processing block 1040).

The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of components and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of ordinary skill in the art upon reviewing the description provided herein. Other embodiments may be utilized and derived, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. The figures herein are merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

The description herein may include terms, such as “up”, “down”, “upper”, “lower”, “first”, “second”, etc. that are used only for descriptive purposes and not to be construed as limiting. The elements, materials, geometries, dimensions, and sequence of operations may all be varied for particular applications. Parts of some embodiments may be included in, or substituted for, those of other embodiments. While the foregoing examples of dimensions and ranges are considered typical, the various embodiments are not limited to such dimensions or ranges.

The Abstract is provided to allow the reader to quickly ascertain the nature and gist of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments have more features than are expressly recited in each claim. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

As described herein, a micro-channeled panel heat exchange system is disclosed. Although the disclosed subject matter has been described with reference to several example embodiments, it may be understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the disclosed subject matter in all its aspects. Although the disclosed subject matter has been described with reference to particular means, materials, and embodiments, the disclosed subject matter is not intended to be limited to the particulars disclosed; rather, the subject matter extends to all functionally equivalent structures, methods, and uses such as are within the scope of the appended claims.

Claims

1. A micro-channeled panel heat exchange system comprising: one or more micro-channeled panels, each micro-channeled panel having micro-channels fabricated internally within each micro-channeled panel for transfer of a working fluid, each of the one or more micro-channeled panels having a cover layer diffusion bonded or brazed to the micro-channels, each of the one or more micro-channeled panels having a thickness of no more than two millimeters, each of the one or more micro-channeled panels being twisted into a non-orthogonal shape; andone or more manifolds coupled to the one or more micro-channeled panels to circulate the working fluid through the micro-channels within each micro-channeled panel.

2. The micro-channeled panel heat exchange system of claim 1 wherein each micro-channeled panel is fabricated from a material selected from a group consisting of: stainless steel alloys, SS300 series, titanium, nickel alloys, ferretics, and carbon steel.

3. The micro-channeled panel heat exchange system of claim 1 wherein the one or more manifolds are fabricated from a material selected from a group consisting of: aluminum, copper, titanium, carbon steel, and nickel alloys.

4. The micro-channeled panel heat exchange system of claim 1 wherein each micro-channeled panel is fabricated using a process selected from a group consisting of: chemical etching, an additive process, a laser-based process, electrochemical machining (ECM), electrical discharge machining (EDM), computer numerical controlled (CNC) machining, mechanical machining, and grinding.

5. The micro-channeled panel heat exchange system of claim 1, wherein the working fluid is selected from a group consisting of: carbon dioxide, helium, water, hydrogen, molten salt, liquid metals, and supercritical carbon dioxide (sCO2).

6. The micro-channeled panel heat exchange system of claim 1 wherein each of the one or more micro-channeled panels is formed into a spiral shape.

7. The micro-channeled panel heat exchange system of claim 1 further including a heated exhaust gas conduit, the one or more micro-channeled panels being installed within the heated exhaust gas conduit.

8. The micro-channeled panel heat exchange system of claim 1 wherein surfaces of each of the one or more micro-channeled panels include heat transfer enhancing features.

9. A method for fabricating a micro-channeled panel heat exchange system, the method comprising: fabricating one or more micro-channeled panels, each micro-channeled panel having micro-channels fabricated internally within each micro-channeled panel for transfer of a working fluid, each of the one or more micro-channeled panels having a cover layer diffusion bonded or brazed to the micro-channels, each of the one or more micro-channeled panels having a thickness of no more than two millimeters;twisting the one or more micro-channeled panels into a non-orthogonal shape;coupling one or more manifolds to each of the one or more micro-channeled panels to circulate the working fluid through the micro-channels within each micro-channeled panel; andenabling passage of heated exhaust gas across surfaces of the one or more micro-channeled panels.

10. The method of claim 9 wherein each micro-channeled panel is fabricated from a material selected from a group consisting of: stainless steel alloys, SS300 series, titanium, nickel alloys, ferretics, and carbon steel.

11. The method of claim 9 wherein the one or more manifolds are fabricated from a material selected from a group consisting of: aluminum, copper, titanium, carbon steel, and nickel alloys.

12. The method of claim 9 wherein each micro-channeled panel is fabricated using a process selected from a group consisting of: chemical etching, an additive process, a laser-based process, electrochemical machining (ECM), electrical discharge machining (EDM), computer numerical controlled (CNC) machining, mechanical machining, and grinding.

13. The method of claim 9 wherein the working fluid is selected from a group consisting of: carbon dioxide, helium, water, hydrogen, molten salt, liquid metals, and supercritical carbon dioxide (sCO2).

14. The method of claim 9 wherein each of the one or more micro-channeled panels is formed into a spiral shape.

15. The method of claim 9 further including providing a heated exhaust gas conduit, the one or more micro-channeled panels being installed within the heated exhaust gas conduit.

16. The method of claim 9 wherein surfaces of each of the one or more micro-channeled panels include heat transfer enhancing features.