US20120160451A1 - Refold heat exchanger - Google Patents
Refold heat exchanger Download PDFInfo
- Publication number
- US20120160451A1 US20120160451A1 US13/335,824 US201113335824A US2012160451A1 US 20120160451 A1 US20120160451 A1 US 20120160451A1 US 201113335824 A US201113335824 A US 201113335824A US 2012160451 A1 US2012160451 A1 US 2012160451A1
- Authority
- US
- United States
- Prior art keywords
- edge
- heat exchange
- fins
- exchange element
- flow divider
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
- F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
- F28D1/03—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits
- F28D1/0391—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits a single plate being bent to form one or more conduits
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
- F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
- F28F3/025—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being corrugated, plate-like elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
- B21D53/04—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of sheet metal
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/4935—Heat exchanger or boiler making
Definitions
- the present disclosure generally relates to systems and methods of transferring heat between fluids and, in particular, heat exchangers configured to transfer heat between continuous flows of two fluids.
- FIGS. 1A and 1B Industrial processes and consumer products often operate by transferring heat between two fluids.
- An example is a household refrigerator wherein, in a very simplified view, a circulating coolant absorbs heat from a refrigerated space and then rejects the heat to the ambient air.
- the heat exchange portions of conventional heat transfer systems typically have fins such as shown in FIGS. 1A and 1B attached to the tubing carrying the coolant.
- These types of heat exchangers can be complex to fabricate and have an operational performance limit determined by the surface area of the interior of the tube and the mean path that heat must travel from the fluid to the air.
- FIG. 1C depicts a typical flexure tube section, showing the circumferential corrugations. As the corrugations are oriented perpendicular to the flow through the tube, the fluid within the folds of the corrugations may be stagnant or cause significant drag on the fluid flow through this section.
- One of the drawbacks of conventional heat exchangers is that the fluid to be cooled is exposed only to a limited surface area, typically the interior surface of a smooth cylindrical tube.
- Another drawback is the difficulty in attaching fins to the tube carrying the fluid to be cooled to improve the thermal coupling of the tube to the external air. Fins can be formed separately and then placed around the tube, which may not provide a good thermal bond between the fins and the tube, or the fins can be brazed or otherwise thermally bonded to the tube in a secondary operation.
- the heat exchanger can be formed from a thick tube and the fins machined directly into the tube or formed by helically co-extruding fins over a central flow tube, both of which produce good thermal connection between the tube and the fins, but the high cost of these techniques typically limit their use to aerospace applications where the added performance is worth the incremental cost.
- the performance of a finned heat exchanger of the type shown in FIGS. 1A and 1B are limited by the long mean thermal path that heat must travel from the interior wall of the tube through the fins to reach the air or other cooling fluid.
- the heat exchange element and heat exchangers disclosed herein overcome the drawbacks of conventional heat exchangers by providing a large surface area in contact with the fluid to be cooled and/or the surface area in contact with the cooling fluid and a short mean distance for heat to travel between two fluids.
- Heat exchangers comprising the disclosed heat exchange elements may be less expensive to manufacture and may provide superior performance to conventional heat exchangers.
- a heat exchange element in certain configurations, includes a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet.
- the folded sheet comprises a plurality of hollow fins.
- the heat exchange element also includes a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold. A plurality of interior tips of the plurality of hollow fins is in contact with the flow divider.
- the heat exchange element also includes a base element coupled to a perimeter of the opening of the interior volume. The base element comprises an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.
- a refold heat exchanger for transferring heat from a first fluid to a second fluid.
- the heat exchanger comprises a plurality of heat exchange elements.
- Each heat exchange element includes a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet.
- the folded sheet comprises a plurality of hollow fins.
- Each heat exchange element includes a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold. A plurality of interior tips of the plurality of hollow fins is in contact with the flow divider.
- Each heat exchange element also includes a base element coupled to a perimeter of the opening of the interior volume.
- the base element comprises an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.
- the first edge of a first heat exchange element is not sealed to the first edge of an adjacent second heat exchange element.
- a method of forming a heat exchange element includes the steps of folding a sheet of material to form hollow fins across a width of the sheet to form a folded sheet, flattening a first edge and a second edge of the folded sheet to respectively form first and second flat edges, lifting a portion of the first flat edge and a portion of the second flat edge, refolding the folded sheet such that a first portion of the folded sheet is proximate to a second portion of the folded sheet to form a refolded sheet, sealing the first flat edge and the second flat edge of the refolded sheet to form an interior volume comprising an inlet manifold adjacent to the first flat edge, an outlet manifold adjacent to the second flat edge, and an opening opposite the refold of the folded sheet, and coupling a base element comprising an inlet and an outlet over the opening such that the inlet and outlet are in fluid communication with the inlet manifold and outlet manifold, respectively.
- FIGS. 1A-1B depict conventional heat exchangers.
- FIG. 1C depicts a conventional flexible tubing segment.
- FIGS. 1D and 1E depict a conventional corrugated heat exchanger.
- FIG. 1F depicts a conventional process for manufacturing a corrugated heat exchanger.
- FIG. 2A depicts an exemplary primary surface heat exchanger that comprises a plurality of heat exchange elements according to certain aspects of this disclosure.
- FIG. 2B is a view of the underside of the primary surface heat exchanger of FIG. 2A according to certain aspects of this disclosure.
- FIGS. 3A-3B depict details of the construction of an exemplary primary surface heat exchange element according to certain aspects of this disclosure.
- FIGS. 3C-3G depict an exemplary manufacturing process 80 for a primary surface heat exchange element according to certain aspects of this disclosure.
- FIGS. 4A-4E depict another configuration of a primary surface heat exchange element according to certain aspects of this disclosure.
- FIGS. 5A-5C depict another configuration of a primary surface heat exchange element according to certain aspects of this disclosure.
- FIG. 6 depicts schematically the flow of the two fluids relative to the primary surface heat exchanger of FIG. 2A according to certain aspects of this disclosure.
- FIG. 7A depicts two examples of refold heat exchangers formed from primary surface heat exchange elements according to certain aspects of this disclosure.
- FIG. 7B-7C illustrate a first configuration of a primary surface heat exchanger wherein the fins are straight according to certain aspects of this disclosure.
- FIG. 7D-7E illustrate a second configuration of a primary surface heat exchanger wherein the fins are formed with a wave pattern according to certain aspects of this disclosure.
- FIG. 7F depicts the height and base width of a flow path in a conventional corrugated heat exchanger.
- FIG. 7G depicts the height and width of a generally rectangular passage within a fin of a primary surface heat exchange element according to certain aspects of this disclosure.
- FIG. 8A depicts an exemplary fabrication process for an example plate-fin heat exchange element according to certain aspects of this disclosure.
- FIGS. 8B-8C depicts details of the construction of the heat exchange sheet fabricated using the process depicted in FIG. 8A according to certain aspects of this disclosure.
- FIG. 9 is a perspective cut-away view of another example configuration of a plate-fin heat exchanger according to certain aspects of this disclosure.
- FIGS. 10A-10B depicts additional details of the construction of the plate-fin heat exchanger shown in FIG. 9 according to certain aspects of this disclosure.
- FIGS. 11A-11B depicts a heat exchanger comprising primary surface heat exchange elements according to certain aspects of this disclosure.
- FIG. 12A depicts an exemplary heat exchanger system comprising a refold heat exchanger according to certain aspects of this disclosure.
- FIG. 12B depicts the operation of the heat exchange system of FIG. 12A according to certain aspects of this disclosure.
- FIGS. 13A-13C depict the construction of a large heat exchange system comprising heat exchange elements according to certain aspects of this disclosure.
- FIG. 14 depicts an exemplary manufacturing process for a primary surface heat exchange element according to certain aspects of this disclosure.
- FIG. 15 depicts an exemplary manufacturing process for a plate-fin heat exchange element according to certain aspects of this disclosure.
- the following description includes examples of heat exchange elements having a finned wall providing improved thermal coupling between fluids on opposite sides of the wall. Walls of these heat exchangers are folded to form a series of hollow fins having a relatively large height-to-width ratio, compared to conventional heat exchangers, and therefore a larger surface than a circular tube having an equivalent cross-sectional area.
- primary surface heat exchange elements One general type of the disclosed heat exchange elements, referred to herein as “primary surface” heat exchange elements, is designed such that the fluids are separated by only the thickness of the wall that is formed into a series of hollow fins.
- the fluid inside the heat exchange element flows primarily through passages within the hollow fins, thereby providing a very short mean thermal path between the fluids.
- a primary surface heat exchanger is over 11 times more efficient, on a volume basis, than a conventional shell-and-tube heat exchanger.
- the manufacturing process for a primary surface heat exchange element is easily modified to form fins having different heights, widths, and separations as well as to produce heat exchange elements having a range of widths in the flow direction, thereby allowing the heat transfer characteristics to be easily tailored to particular applications.
- the use of size-specific tooling is reduced or eliminated, thereby simplifying the manufacturing process and the change-over process for reconfiguring a production line to produce a different size of heat exchange element.
- a second general type of heat exchange element referred to herein as “plate-fin” heat exchange elements, has a separation wall with finned heat-coupling walls attached and thermally coupled to one or both sides, thereby increasing the surface area exposed to the fluid on that side of the separation wall.
- the additional surface area provided by the heat-coupling walls improves the rate of heat transfer.
- a plate-fin heat exchanger can be over 4 times more efficient, on a volume basis, than a conventional shell-and-tube heat exchanger. Similar to the primary surface heat exchanger, the manufacturing process for a plate-fin heat exchange element is easily modified to provide heat exchange elements over a range of widths, lengths, and fin dimensions to provide a range of performance capabilities.
- Heat exchangers built from either type of heat exchange element are modular and extensible, making it a straightforward activity to provide heat exchanges over a wide range of sizes and capabilities, as is shown herein.
- the improved performance of primary surface or plate-fin heat exchangers allows a given application to use a heat exchanger that may be an order of magnitude smaller than a conventional device.
- the method and system disclosed herein are presented in terms of counterflow heat exchangers configured to transfer heat from a first fluid to a second fluid. It will be apparent to those of skill in the art that the heat exchange elements disclosed herein may be used in other types of heat exchangers, such as immersion heat exchangers wherein the external fluid is not actively circulated. In addition, the heat exchange elements are presented as being fabricated from sheet metal in a sequential forming process, whereas it will be apparent to those of skill in the art that the disclosed structures can be fabricated from other materials and/or using other techniques, such as extrusion of a plastic material. None in this disclosure should be interpreted, unless specifically stated as such, to limit the application of any method or system disclosed herein to a particular material, form factor, or fabrication process. Other configurations of heat transfer systems are known to those of skill in the art and the application of the components and principles disclosed herein to other systems will be apparent.
- FIGS. 1A and 1B depict conventional heat exchangers 10 and 20 .
- FIG. 1A is a cut-away view of a conventional heat exchanger 10 having a central tube 12 with radial fins 14 attached to the outside of the tube 12 .
- the fins 14 can be either individual generally planar fins or one or more spiral fins that are continuous along the tube 12 .
- FIG. 1B depicts a heat exchanger 20 having fins 14 arranged longitudinally along a smooth-wall tube 12 similar to the tube 12 of FIG. 1A .
- FIG. 1C depicts a conventional flexible tubing segment 22 .
- the tube 15 has a series of circumferential corrugations 16 formed in the side wall.
- the circumferential corrugations 16 are provided solely to allow the tube 15 to bend sideways without the tube 15 collapsing or being reduced in cross-sectional area.
- the circumferential corrugations 16 may induce additional flow resistance as the flow path through the tube 15 is perpendicular to the corrugations 16 .
- FIGS. 1D and 1E depict a conventional corrugated heat exchanger disclosed in U.S. Patent Application Publication No. 2005/0217836.
- FIG. 1D shows a core structure 23 formed from a continuous corrugated sheet 24 folded in a “Z” pattern with corrugated cut sheets 25 inserted between each fold.
- the corrugations of the continuous sheet 24 and the cut sheets 25 are both formed in a 45° zig-zag pattern, i.e. alternating straight sections wherein each straight section is at right angles to both adjacent straight sections.
- Four formed headers 26 are coupled to the four corners of the core structure 23 as shown in FIG. 1D .
- FIG. 1E shows an assembled conventional corrugated heat exchanger wherein the core structure 23 has been coated on the ends and the exposed sides with a sealing compound 27 .
- the pair of headers 26 , 26 ′ on each side are fluidically coupled such that a flow 28 will enter the inlet header 26 at the front of the right side and emerge from the outlet header 26 ′ on the right side.
- As the width of the sheets 25 is the same as the width of the continuous sheet 24 , there is no internal manifold space at either end.
- the flow 28 must zig-zag through the corrugations of the cut sheets 25 and cross-oriented corrugations of the continuous sheet 24 to reach the far side of the interior volumes connected to the header 26 .
- flow 28 is shown as a single line that turns corners, in reality flow 28 is a diffuse flow that spreads from the header across and downstream then converges to the outlet header 26 ′. Similarly, a separate flow 29 entering the inlet header 26 at the back of the left will flow in a diffuse pattern through the spaces between the cut sheets 25 and the continuous sheet 24 and then exit from the outlet header 26 ′ at the front on the left side.
- the heat exchanger of FIGS. 1D and 1E may be complex to manufacture as the headers 26 , 26 ′ are either stamped and folded from sheet metal or molded in the final shape but, in either case, are four additional pieces that must be formed, inventoried, handled, and attached to the core structure 23 .
- application of the sealing compound 27 is a complex task and may be difficult to complete without the formation of leaks.
- the flows 28 and 29 are shown as counterflows within the core structure 23 , the tortuous path between the inlet header 26 and outlet header 26 ′ does not make efficient use of the entire enclosed volume and certain portions of the internal volume, for example, the corners, are likely to be dead spaces.
- FIG. 1F depicts a conventional process 210 disclosed in U.S. Pat. No. 6,915,675 for manufacturing a corrugated heat exchange material.
- a sheet 211 of a formable material is fed into a pair of mated corrugating rollers 214 , 215 that form corrugations in the sheet 211 .
- These corrugations are limited in shape to the profiles of non-undercut gear teeth. This limits the aspect ratio, i.e. the ratio of the height of the corrugations to the base width of the corrugations.
- a plunger 216 is positioned to extend when the smooth sections of the sheet 211 are positioned under the plunger 216 , thereby forming a joined series of corrugated folded sections 230 .
- FIG. 2A depicts an exemplary refold heat exchanger 30 that comprises a plurality of primary surface heat exchange elements 32 according to certain aspects of this disclosure.
- the heat exchange elements 32 are formed from a continuous sheet of folded metal, i.e. a sheet having a series of fins formed by folding a smooth sheet, that has been refolded to form the walls 40 and ends 42 of each of the heat exchange elements 32 .
- the construction of a primary surface heat exchange element 32 is discussed in greater detail with respect to FIGS. 3A-3G .
- FIG. 2B is a view of the underside of the refold heat exchanger 30 of FIG. 2A according to certain aspects of this disclosure.
- a base element comprising panels 34 A, 34 B, and 34 C has been coupled to the openings formed by the refolded folded metal sheet so as to form inlets 36 and an outlets 38 for all of the heat exchange elements 32 .
- FIGS. 3A-3B depict details of the construction of an exemplary primary surface heat exchange element 32 according to certain aspects of this disclosure.
- FIG. 3A a portion of the walls 40 and the end 42 have been removed to make the interior volume 44 visible and illustrate how a flow divider 46 is positioned within the interior volume 44 . It can be seen how the finned sheet of wall 40 continues from the bottom edge of both walls in a 180° bend to form a wall 40 of adjacent heat exchange elements 32 (not shown) so as to collectively form a refold heat exchanger 30 such as shown in FIG. 2A .
- FIG. 3B is an enlarged view of the end 42 of heat exchange element 32 illustrating how the fins 45 , described in greater detail with respect to FIGS. 3D and 4D , of the two walls 40 are flattened to form flat edges 42 A, 42 B that are sealed to each other to form an end 42 .
- the flat edges 42 A, 42 B are offset from a plane defined by the interior tips of the fins 45 of walls 40 .
- the flat edges 42 A, 42 B are welded to each other.
- the flat edges 42 A, 42 B are brazed to each other.
- the flat edges 42 A, 42 B are soldered to each other.
- the flat edges 42 A, 42 B are bonded to each other.
- FIGS. 3C-3G depict an exemplary manufacturing process 80 for a primary surface heat exchange element 32 according to certain aspects of this disclosure.
- FIG. 3C depicts the overall production line 80 starting with rolls 82 of sheet metal or other formable sheet material, for example a thermoformable plastic.
- the sheet material is metal foil having a thickness in the range of 0.003-0.010 inches.
- the unformed continuous sheet 83 A is supplied from roll 82 into a fin folding tool 84 that, in this example, forms the entire width of the sheet 83 A into a series of fins thereby producing the folded sheet 83 B.
- the folded sheet 83 B has 20-45 fins per inch.
- the folded sheet 83 B is passed through a pair of edge formers 86 (only the near former 86 is visible in FIG. 3C and in FIG. 3E ) that flatten the ends of the fins 45 to form a flat edge 42 C and form/lift the flat edge 42 C along the edge of the folded sheet 83 B to form a formed folded sheet 83 C having an offset flat edge 42 C, as seen in FIG. 3F , along each edge.
- the formed folded sheet 83 C is refolded into a continuous series of double-layer panels.
- FIG. 3G shows the refolding process with the tooling removed for clarity.
- the adjacent edges of the double-layer panels are sealed (the sealing tool is not shown in FIG. 3C ) to each other, for example by welding, brazing, soldering, adhesive bonding, or other joining technology.
- the free edges of the sheet 83 C are pre-welded, i.e. melted to form a bead along the free edge.
- pre-welding is accomplished using a standard welding/heating process, such as an electric arc, tungsten inert gas (TIG) welding, and laser welding.
- TIG tungsten inert gas
- This pre-welding consolidates the flattened portion of the offset flat edge 42 C, adding strength and handleability to the sheet 83 C.
- additional material for example a foil strip, is provided along the edge prior to the pre-welding process and is melted into the bead, thereby further adding stiffness to the edge of the sheet 83 C.
- the quality of the welds are improved by pre-welding the edges.
- a base element in this example continuous sheets of metal provided from rolls 90 A, 90 B, and 90 C, is coupled (the coupling tool is not shown in FIG. 3C ) to the underside of the sealed double-layer panels to form panels 34 A, 34 B, and 34 C, seen in FIG. 2B , to form the inlets 36 and outlets 38 (not visible in FIG. 3C but also visible in FIG. 2B ) and produce a continuous series of the heat exchange elements 32 .
- the connected string of primary surface heat exchange elements are segmented (a process not shown in FIG. 3C ) into groups to form refold heat exchangers 30 or other configurations of refold heat exchangers.
- the production line 80 includes an insertion station (not shown in FIG. 3C ) between the forming tools 88 and the addition of the panels 34 A, 34 B, and 34 C to insert flow dividers 46 into the interior space 44 of each double-layer panel.
- FIG. 3D is an enlarged view of the region indicated by the dashed-line box 3 D in FIG. 3C .
- the sheet 83 A is folded into fins 45 having rounded tops and bottoms with a primary width 92 and a secondary width 94 and a fin height 96 .
- the tops and bottom of the fins 45 have non-round profiles.
- the widths 92 , 94 may be equal in some cases while in other cases the widths 92 , 94 are different.
- the widths 92 , 94 determine the fins per inch (FPI) of the refold heat exchanger 30 .
- the height 96 of the fins 45 may vary along the length of sheet 83 B and in the heat exchangers 32 .
- FIG. 3E is an enlarged view of the region indicated by the dashed-line box 3 E in FIG. 3C .
- Sheet 83 B having fins formed across the full width of the sheet is fed into the edge-forming tool 86 that flattens, or crushes, the fins along the edge into a flat edge 42 C to form sheet 83 C.
- FIG. 3F is an enlarged view of the region indicated by the dashed-line box 3 F in FIG. 3C showing the flat edge 42 C and the central fins 45 previously shown in FIGS. 3A and 3B . It can be seen that the flat edge 42 C is offset from the bottom of the fins in the central portion of the sheet 83 C.
- the flat sheet 83 A can be formed into corrugations across only the center section of the sheet (not shown) leaving flat regions 42 C along each edge, thereby eliminating the need to reform a flat edge from a finned profile.
- the ability to form the configuration of sheet 83 C having fins in the center and flat edges depends at least in part on the material and the thickness of the sheet 83 A.
- Alternate manufacturing processes can includes stamping (not shown) of metal or plastic sheets to directly form continuous sheets or discrete panels (not shown) having the fins 45 and flat edges 42 C of the formed folded sheet 83 C as well as vacuum forming, pressure forming, or hydroforming (all not shown) of the fins 45 and edges 42 C.
- the top edges and/or bottom edges of discrete panels may be joined with header and/or footers (not shown) to form heat exchange elements 32 .
- side elements (not shown) may be used in place of the flattened portions 42 C to join the side edges of the discrete double-layer panels.
- a bulk material such as a thermoset resin, may be molded, such as by compression molding or injection molding, directly into the shape of finned sheet 83 C of an appropriate size to form side walls 40 of a heat exchange element 32 .
- FIG. 3G is an enlarged view of the region indicated by the dashed-line box 3 G in FIG. 3C showing the folding of the formed folded sheet 83 C with the folding tool removed to reveal the forming process. It can be seen how the flat edges 42 C of a double-layer panel are positioned proximate to each other prior to being bonded to each other, for example by solder, to form the edge 42 of a heat exchange element 32 .
- This continuous series of heat exchange elements 32 can be segmented in groups so as to form refold heat exchangers 30 as are shown in FIG. 7A .
- FIGS. 4A-4E depict a configuration of a primary surface heat exchange element 32 A according to certain aspects of this disclosure.
- the flow divider 46 is omitted and the interior tips 56 of fins 45 of the two walls 40 A and 40 B are touching.
- FIG. 4A is a cut-away side view of the heat exchange element 32 A wherein the interior surface of wall 40 A is visible.
- the areas 42 that are sealed to the near wall 40 B are shown as hatched areas 42 at the left and right edges of the wall 40 A.
- the adjacent areas 48 B and 48 C, hatched at an angle opposite to the hatching of the ends 42 are smooth-walled volumes that form an inlet manifold 48 B and an outlet manifold 48 C.
- fins 45 pass from the inlet manifold 48 B to the outlet manifold 48 C.
- the edges of bottom panels 34 A, 34 B, and 34 C are visible along the bottom of the wall 40 A.
- FIG. 4B is a cross-section view of a complete primary surface heat exchange element 32 A taken along the section line 4 B- 4 B in FIG. 4A .
- the walls 40 A and 40 B are smooth with the full width of the heat exchange element 32 A separating the walls 40 A, 40 B so as to form the inlet manifold 48 B.
- the seam 42 D between the flanges 42 A and 42 B is visible in FIG. 4B as a vertical line on the interior surface of the end 42 .
- FIG. 4C is a cross-section view of a complete primary surface heat exchange element 32 A taken along the section line 4 C- 4 C in FIG. 4A .
- the fins 45 of walls 40 A and 40 B can be seen to be touching each other.
- the shaded areas indicate the interior volume of the heat exchange element 32 A that would be wetted by a fluid contained within the interior volume 44 . It can also be seen how the finned sheet forming wall 40 A folds over in a 180° bend to form a top 43 and then continue as part of wall 40 B.
- FIG. 4D is an enlarged view of the portion of FIG. 4C enclosed in the dashed-line circle 4 D. It can be seen how the series of hollow fins 45 are formed as a series of convex folds 52 that alternate with concave folds 54 . The convex and concave folds 52 , 54 are alternately connected by sidewalls 58 . Each concave fold 54 has a tip 56 on the side facing the interior volume 44 .
- Each fin 45 has an interior passage 44 A bounded by the convex fold 52 , the two sidewalls 58 A and 58 B connected to the convex fold 52 , and a plane connecting the tips 56 A, 56 B of the two concave folds 54 A, 54 B connected to the respective sidewalls 58 A, 58 B.
- FIG. 4C it can be seen how the only flow paths from the inlet manifold 48 B to the outlet manifold 48 C are through one of interior passages 44 A of the plurality of fins 45 formed by the finned sheets of walls 40 A or 40 B.
- FIG. 4E is a cross-section view of a complete primary surface heat exchange element 32 A taken along the section line 4 E- 4 E in FIG. 4A . Ends 42 are visible at the left and right sides.
- the two-step offset in regions of the inlet and outlet manifold 48 B, 48 C provide flow space past the narrow section to allow fluid to pass along the outside of fins 45 when two heat exchange elements 32 A are positioned adjacent to each other with the fins 45 in contact. It can be seen how interior passages 44 A of either wall 40 A or 40 B are the sole fluid pathways between inlet manifold 48 B and outlet manifold 48 C.
- FIGS. 5A-5C depict another configuration of a primary surface heat exchange element 32 B according to certain aspects of this disclosure.
- FIG. 5A is a cut-away side view of the heat exchange element 32 B wherein the flow divider 46 and the interior surface of wall 40 A is visible.
- the fins 45 extend from one end 42 to the other end 42 .
- a flow divider 46 is disposed within the interior volume 44 between the inlet 36 and the outlet 38 .
- the flow divider 46 functions to force essentially all of the flow of fluid passing from the inlet manifold 48 B to the outlet manifold 48 C to flow through the passages 44 A formed within the hollow fins 45 , thereby increasing the amount of time that each element of the fluid is within close proximity to a wall 45 and thereby improving the heat transfer from the fluid to the wall 45 .
- the flow divider 46 comprises a solid portion having two parallel planar solid surfaces, as is shown in FIG. 3A .
- the flow divider 46 comprises a foam material.
- the flow divider 46 comprises a coating over a foam core.
- the flow divider 46 comprises a metal formed into a hollow or solid shape. The flow divider may be formed as any structure that blocks the flow of fluid between the inlet manifold 48 B and the outlet manifold 48 C outside of the interior passages 44 A.
- FIG. 5B is a cross-section view of a complete primary surface heat exchange element 32 B taken along the section line 5 B- 5 B through the inlet manifold in FIG. 5A . It can be seen how the tips 56 of the walls 40 A and 40 B are separated by a distance equal to the thickness of flow divider 46 , shown as a dashed outline 46 A in FIG. 5B .
- FIG. 5C is a cross-section view of a complete primary surface heat exchange element 32 B taken along the section line 5 C- 5 C in FIG. 5A . It can be seen that flow divider 46 fills the interior volume 44 and the tips 56 of fins 45 contact the flow divider 46 . As previously discussed with respect to heat exchange element 32 A in FIGS. 4A-4E , it can be seen that interior passages 44 A of either wall 40 A or 40 B form the sole fluid path between inlet manifold 48 B and outlet manifold 48 C.
- FIG. 6 depicts schematically the flow of the two fluids 50 and 60 relative to the refold heat exchange element 32 of FIG. 2A according to certain aspects of this disclosure.
- FIG. 6 is a cut-away side view of heat exchange element 32 B wherein flow divider 46 and the interior surface of fins 45 of wall 40 A are visible.
- the fluid 50 is in contact with the outside surfaces of heat exchange element 32 while fluid 60 is provided at the inlet 36 and removed from outlet 38 through external conduit (not shown in FIG. 6 ).
- the fluid 50 is flowing from right to left, in the view of FIG. 6 , and is in contact with the external surfaces of the fins 45 of both the visible wall 40 A and the removed wall 40 B.
- Fluid 60 is introduced through inlet 36 into the inlet manifold 48 B which serves to distribute the fluid 60 across the plurality of fins of both walls 40 A and 40 B.
- the fluid 60 flows through the interior passages 44 A of the plurality of fins 45 and into the outlet manifold 48 C.
- the presence of the open inlet and outlet manifolds 48 B, 48 C serve to evenly distribute the flow across all of the passages 44 A, i.e. without a difference in the pressure drop from the inlet to each of the interior passages 44 A, such that the overall performance of the primary surface heat exchange element 32 B is improved.
- the fluid in the outlet manifold exits through outlet 38 .
- this heat exchange element 32 has been implemented as part of a counterflow heat exchanger wherein the direction of flow of the fluid 60 within the heat exchange element 32 is opposite the direction of flow of the fluid 50 .
- fluid 60 is a coolant rejecting heat to the fluid 50 .
- fluid 50 is a gas.
- fluid 50 is ambient air.
- fluid 60 is a liquid.
- FIG. 7A depicts two examples 30 D and 30 E of refold heat exchangers formed from configurations 32 D and 32 E, respectively, of primary surface heat exchange elements 32 according to certain aspects of this disclosure.
- the comparison of the two refold heat exchangers 30 D and 30 E illustrates how the height of the heat exchange elements 32 can be easily changed according to the needs of a particular application.
- the width of the heat exchange elements, the separation of the heat exchange elements, and the heights and widths of the fins 45 can also be easily varied to adapt the design to particular applications.
- the fins 45 of heat exchangers 30 D and 30 E are formed with a “wave” pattern along the length of the fins 45 . This pattern is advantageous to prevent nesting of the fins 45 of adjacent heat exchange elements 32 , as is discussed in greater detail with respect to FIGS. 7B and 7C .
- FIG. 7B-7C illustrate a first example configuration of a primary surface heat exchange element 32 wherein the fins 45 are straight, i.e. without the wave pattern seen in FIG. 7A , according to certain aspects of this disclosure.
- the fins 45 of a first heat exchange element 32 are positioned with the peak of each fin 45 positioned as indicated by the solid lines 65 .
- the fins 45 of a second adjacent heat exchange element 32 are positioned such that the peaks of the fins of the second adjacent heat exchange element 32 are positioned as indicated by the dashed lines 64 . If the two sets of fins 45 are pressed against each other, the fins 45 of the two heat exchange elements 32 can become interleaved.
- FIG. 7C is a cross-section of the fin arrangement of FIG. 7B taken along the section line 7 C- 7 C.
- FIG. 7C illustrates how the fins 45 can become nested when the peaks 66 , 67 are offset from each other with straight fins 45 . This nesting may reduce the efficiency of the heat exchanger 30 and possibly damage the heat exchange elements 32 .
- FIG. 7D-7E illustrate a second example configuration of a primary surface heat exchange element 32 wherein the fins 45 are formed with a wave pattern as shown in FIG. 7A according to certain aspects of this disclosure.
- the peaks of each fin 45 of a first heat exchange element 32 are positioned as indicated by the solid lines 67 .
- the peaks of the fins 45 of the adjacent heat exchange element 32 are positioned as indicated by the dashed lines 66 . It can be seen that the wave pattern is reversed and therefore the lines 66 and 67 cross repeatedly along the length of the heat exchange element 32 . If the two sets of fins 45 are pressed against each other, the fins 45 of the two heat exchange elements 32 cannot become nested.
- FIG. 7E is a cross-section of the fin arrangement of FIG. 7D taken along the section line 7 E- 7 E.
- the location of the fins 45 on the plane of the cross-section 7 E- 7 E are shown in the light shading whereas the portion of the same fins 45 are shown in dark gray further from the plane of the cross-section plane 7 E- 7 E. It can be seen that the dark portions of the fins 45 that are associated with curves 66 overlap the dark portions of the fins 45 associated with curves 67 , which is shown in FIG. 7D by the crossing of the lines 66 and 67 . The two sets of fins 45 cannot become nested.
- FIG. 7F depicts the height H 1 and base width W 1 of a flow path in a conventional corrugated heat exchanger as seen in FIG. 1D .
- the triangular corrugations of continuous sheet 24 are perpendicular to the triangular corrugations of cut sheet 25 , creating the flow area 17 at each peak of the cut sheet 25 .
- a height H 1 and a base width W 1 are defined for this flow area 17 as shown in FIG. 7F .
- the ratio of H 1 to W 1 is 0.5.
- FIG. 7G depicts the height H 2 and width W 2 of a generally rectangular passage 44 A within a fin 45 of a primary surface heat exchange element 32 according to certain aspects of this disclosure.
- the sides of fin 45 are parallel and form a generally rectangular passage 44 A. While the top of fin 45 is rounded and the bottom corners are splayed outward as they connect to the adjacent fins 45 , the shape of the passage 44 A is still considered to be generally rectangular with a width of W 2 and a height of H 2 .
- the ratio of H 2 to W 2 is greater than 1.0, and may be approximately 4.0 in the example of FIG. 7G .
- the walls of fin 45 may be slightly angled based on resilience of the material of the walls of fin 45 or tooling clearances, it may still be considered generally rectangular if the angles are not too severe. If the walls become significantly angled and cannot be considered to form a generally rectangular passage 44 A, then a base width similar to that shown in FIG. 7F is used to evaluate the ratio of the passage 44 A.
- FIG. 8A depicts an exemplary fabrication process for an example plate-fin heat exchange element 120 according to certain aspects of this disclosure.
- a sheet 102 of material for example aluminum or copper or other metal or metal alloy
- the brazing material comprises a flux.
- the brazing material is applied as a film without spraying. Additional sheets of material, for example aluminum or copper or other metal or metal alloy, are provided from rolls 101 A and 101 B and passed through fin-forming tools 104 A and 104 B, respectively.
- the fin-forming tools 104 A and 104 B fold the sheets from rolls 101 A, 101 B into fins 45 across the full widths of the folded sheets 105 and 106 , respectively.
- the folded sheets 105 , 106 are brought into contact with the two surfaces of sheet 102 and, in this example, passed through a braze oven 110 .
- the brazing material previously applied to sheet 102 melts and bonds the three sheets 102 , 105 , 106 together.
- the bonded sheets pass through edge-forming tools 112 that, in this example, form and offset the edges of the center sheet 102 into smooth “S” shapes, thereby finishing the fabrication of the heat exchange sheet 100 . Additional details of the heat exchange sheet 100 are discussed with respect to FIG. 8B .
- the continuous sheet of heat exchange sheet 100 is refolded in operation 114 (the refolding tool is not shown in FIG. 8 A 0 to form double-layer panels that, when bonded together, form plate-fin heat exchange elements 120 that are discussed in greater detail with respect to FIG. 9 .
- FIGS. 8B-8C depict details of the construction of the heat exchange sheet 100 fabricated using the process depicted in FIG. 8A according to certain aspects of this disclosure.
- the tips of the fins 45 of sheets 105 , 106 that are in contact with sheet 102 are at least partially brazed to the sheet 102 .
- FIG. 8B is a perspective view of the near edge of heat exchange sheet 100 . It can be seen that the width of the upper folded sheet 105 is less than the width of the center sheet 102 and the portion of the center sheet 102 that extends past the folded sheet 105 is formed into an “S” that, in this configuration, is offset by a distance that is equal to the height of the find formed in the lower folded sheet 106 .
- the width of the folded sheet 106 is less than the width of the finned sheet 105 .
- the folded sheet 106 is centered on sheets 102 , 105 such that two equal spaces 108 are formed at each end.
- the folded sheet 106 is disposed between the ends of sheets 102 , 105 and offset from the center towards one side such that unequal spaces 108 are formed at each end.
- the fins 45 of sheets 105 , 106 are open at each end.
- FIG. 8C is a cross-section end view of the heat exchange sheet 100 at the point along the production line where FIG. 8B is taken from.
- the center sheet 102 is formed at each end into the “S” shape and the folded sheets 105 and 106 are centered on sheet 102 .
- Spaces 108 A, 108 B are provided at each end of the folded sheet 106 .
- FIG. 9 is a perspective cut-away view of another example configuration of a plate-fin heat exchange element 120 according to certain aspects of this disclosure.
- the heat exchange sheet 100 is refolded as shown at the end of the process of FIG. 8A such that the tips of the fins 45 of sheet 106 are in contact. It can be seen in FIG. 9 that at least some of the tips of the fins of sheet 106 A of a first sidewall 122 A of the heat exchange element 100 are in contact with the tips of the fins 45 of sheet 106 B of a second sidewall 122 B.
- the tips of the fins 45 of sheets 105 A also are in contact with the tips of adjacent fins of sheets 105 B.
- the fins 45 of sheets 105 and/or 106 are formed into the “wave” pattern shown in FIGS. 7A-7C so as to reduce the tendency to nest and thereby maintain the tip-to-tip spacing of sheets 105 and 106 shown in FIG. 9 .
- a base element 124 is bonded to the lower folds of the heat exchange element 100 so as to form the sealed interior volume within a single plate-fin heat exchange element 120 .
- multiple parallel heat exchangers 120 can be formed from a continuous heat exchange element 100 .
- FIGS. 10A-10B depict additional details of the construction of the plate-fin heat exchange element 120 shown in FIG. 9 according to certain aspects of this disclosure.
- FIG. 10A is a cross-section end view of a plate-fin heat exchange element 120 A and portions of adjacent plate-fin heat exchange elements 120 B and 120 C.
- the center sheet 102 of FIG. 8B forms a separation wall 132 that cooperates with the base element 124 (not visible in FIG. 10A , shown in FIG. 9 ) to form an interior volume 126 shown as the darker shaded area in this cross-section view.
- the folded sheet 106 forms a first heat coupling wall 136 comprising, in this configuration, a series of fins 130 that are similar to the fins 52 of the primary surface heat exchange element 32 shown in FIG.
- the folded sheet 105 forms a second heat coupling wall 135 comprising, in this example, fins 130 .
- the tips of fins 130 of heat coupling wall 136 are in contact with the tips of fins 130 of the adjacent heat coupling wall 136
- the tips of fins 130 of heat coupling wall 135 of heat exchange element 120 A are in contact with the tips of fins 130 of adjacent heat exchange elements 120 B and 120 C.
- a first fluid 126 A such as a mixture of propylene glycol and water, fills the volume 126 , including both the interior passages of fins 130 and the spaces between fins 130 .
- An external volume 128 i.e. the space outside of the separation wall 102 , is filled with a second fluid 128 A, such as air, which fills the interior passages of fins 130 of folded sheet 105 as well as the spaces between the fins 130 of sheet 105 .
- the outlet manifold 148 C is larger, i.e. longer in the flow direction, than the inlet manifold 148 B to accommodate the expansion of the fluid as it gains heat while flowing through the fins 130 of heat coupling wall 136 .
- This provides a pressure drop across the outlet manifold 148 C that is approximately equal to the pressure drop across inlet manifold 148 B even though the volume of fluid passing through the outlet manifold 148 C is larger than the volume of fluid passing through the inlet manifold 148 B.
- the outlet 38 may be larger, i.e. longer in the flow direction, than the inlet 36 so as to provide pressure drops that are approximately the same.
- first fluid 126 A in volume 126 is hotter than the second fluid 128 A in volume 128 .
- heat is conducted from the first fluid 126 A into both the separation wall 132 directly and into the heat coupling wall 136 .
- the heat coupling wall 136 is thermally conductive, the heat received from the first fluid 126 A passes into the separation wall 132 .
- the presence of the heat coupling wall 136 effectively increases the surface area of the separation wall 132 in contact with the first fluid 126 A.
- the heat coupling wall 136 may improve the overall heat transfer performance of the refold heat exchanger 120 .
- the heat coupling wall 135 receives heat from the separation wall 132 and transfers this heat into the second fluid 128 A in parallel with the direct transfer of heat from the separation wall 132 to the second fluid 128 A. This effectively increases the surface area of the separation wall 132 and reduces the effect of any boundary layer of the second fluid 128 A at the surfaces of the heat coupling wall 135 and the separation wall 132 .
- FIG. 10B is a top cross-section view of the plate-fin heat exchange element 120 A along the dashed line 10 B- 10 B in FIG. 10A .
- the inlet manifold 148 B and outlet manifold 148 C formed by the spaces 108 of FIG. 8B in the heat exchange sheet 100 are shown at each end of the heat coupling wall 136 within the separation walls 132 .
- the “S” shaped portions of center wall 102 have been sealed to each other to form flanges 146 that form a portion of the enclosure of volume 126 .
- the first fluid 126 A and the second fluid 128 A are shown as flowing past and through the heat coupling walls 106 and 105 , respectively, in opposite directions such that the plate-fin heat exchange element 120 A operates as a counterflow heat exchanger.
- FIGS. 11A-11B depicts a heat exchanger 30 E comprising primary surface heat exchange elements 32 E according to certain aspects of this disclosure.
- the heat exchanger 30 E comprises plate-fin heat exchange elements 120 .
- the heat exchanger elements 32 E are arranged in a radial pattern about a central opening 31 such that, relating this configuration to the configuration of FIG. 10A-10B , the second fluid 128 A passes axially through the heat exchanger 30 E, as shown by the arrows 128 A, while the first fluid 126 A is provided through inlet 36 and received from outlet 38 within the opening 31 .
- each of the heat exchange elements 32 E are curved whereas the heat exchange elements 32 and 32 A are generally planar.
- the separation between adjacent heat exchange elements 32 E around the inside edge 140 of opening 31 is less than the separation of the same heat exchange elements 32 E at the outside edge 142 of the heat exchanger 30 E.
- the curved profile of each heat exchange element 32 E increases the length of each heat exchange element 32 E compared to a planar profile arranged in a radial pattern. This fills the entire toroidal-shaped area of the axial cross-section and improves the efficiency, i.e. the heat exchange capability per unit volume, of heat exchanger 30 E compared to a design using radial planar heat exchange elements 32 (not shown).
- the heat exchange elements 32 E are otherwise substantially the same as the heat exchange element 32 or 32 A.
- FIG. 12A depicts an exemplary heat exchanger system 150 comprising a refold heat exchanger 30 according to certain aspects of this disclosure.
- the refold heat exchanger 30 is configured substantially as shown in FIG. 2A , comprising a plurality of primary surface heat exchange elements 32 .
- the heat exchanger 30 comprises plate-fin heat exchange elements 120 .
- the inlet 36 and outlet 38 (not visible in FIG. 12A ) of the heat exchanger 30 are positioned over flow channels in an external manifold 158 such that inlet 160 and outlet 162 of the external manifold 158 are in separate fluid communication with inlet 36 and outlet 38 , respectively.
- a flow enclosure 156 is positioned over the heat exchanger 30 with an inlet 164 and an outlet 166 (not visible in FIG. 12A ).
- FIG. 12B depicts the operation of the heat exchange system of FIG. 12A according to certain aspects of this disclosure.
- a first fluid 60 is initially cooler than a second fluid 50 .
- the “cool” first fluid 60 is provided at the inlet 160 .
- the “hot” second fluid 50 is provided at the inlet 164 of the flow enclosure 156 .
- the direction of flow of the first fluid within the heat exchanger 30 is opposite the direction of flow of the second flow past the outside surfaces of the heat exchanger 30 .
- heat is transferred into the material of the heat exchanger 30 and then into the fluid 60 .
- the first fluid 60 received from the outlet 162 is warmer than fluid 60 entering the inlet 160 and the fluid 50 leaving outlet 166 is cooler than the fluid 50 entering the inlet 164 .
- the first fluid is warmer than the second fluid and the heat transfer is accomplished in the opposite direction, i.e. from the first fluid 60 to the second fluid 50 .
- FIGS. 13A-13B depict the construction of a heat exchange system 200 comprising heat exchange elements 30 according to certain aspects of this disclosure.
- FIG. 13A depicts the assembly of two heat exchangers 30 with an external manifold 158 A that is a double-sided version of the external manifold of FIG. 12A to form a heat exchange subassembly 170 .
- the inlet 160 and outlet 162 of the double-sided external manifold 158 A are separately and respectively coupled to the inlets 36 and outlets 38 of the individual heat exchangers 32 .
- the heat exchange subassembly 170 is an extensible design, i.e.
- the heat exchange capacity of the subassembly 170 is a function of the length L and width W and height H of the heat exchangers 30 as well as the number of heat exchangers. In certain implementations, this function is generally linear over a certain range of proportions between L, W, and H.
- the subassembly 170 comprises primary surface heat exchange elements 32 . In certain embodiments, the subassembly 170 comprises plate-fin heat exchange elements 120 .
- FIG. 13B illustrates a higher-level subassembly 180 comprising multiple subassemblies 170 coupled to a center pipe 181 .
- the center pipe 181 is divided internally into flow paths 186 and 188 and comprises a plurality of paired openings 182 , 184 along the length of the center pipe 181 , wherein the openings 182 are in fluid communication with the flow path 186 and the openings 184 are in fluid communication with flow path 188 .
- the openings 182 are coupled to the inlets 160 of subassemblies 170 and the openings 184 are coupled to the outlets 162 such that flow path 186 is a common inlet to all of the subassemblies 170 and flow path 188 likewise a common outlet to all of the subassemblies 170 coupled to the center pipe 181 .
- FIG. 13C illustrates the top-level heat exchanger system 200 comprising a plurality of the subassemblies 180 of FIG. 13B identified as subassemblies 180 A- 180 D.
- the ends of center pipes 181 of the plurality of subassemblies 180 A- 180 D are coupled in series such that the inlet flow paths 186 are fluidically coupled and the outlet flow paths 188 are likewise fluidically coupled.
- the ends of flow paths 186 and 188 of the end subassembly 170 A respectively form a system inlet 202 and a system outlet 204 .
- a first fluid introduced into the system inlet 202 will flow through the flow paths 186 of all of the subassemblies 180 A- 180 D, then flow into the inlets 160 of each of the subassemblies 170 , and then into the inlets 36 of each of the heat exchangers 30 .
- the first fluid passes through each heat exchanger 30 and out of the outlets 38 , the first fluid is collected in the flow channels of external manifolds 158 A and passes through the outlets 162 into the flow path 188 of the subassemblies 180 and then out through the system outlet 204 .
- the rear opening of the center pipe 181 of the subassembly 180 D can be capped, making the system 200 a stand-alone system, or further connected to another heat exchanger system 200 .
- FIG. 14 is a flow chart 300 of an exemplary manufacturing process for a primary surface heat exchange element 32 according to certain aspects of this disclosure.
- the flow chart 300 is related to the process equipment 80 shown in FIG. 3C .
- a sheet of material 83 A having a first edge and a second edge is folded to form a series of hollow fins 45 , an example fin configuration shown in FIG. 3D , thereby forming a folded sheet 83 B.
- the ends of the fins 45 along the first and second edges are flattened to form a flat edge 42 C on each side.
- the flat edges are lifted, or offset such that the flat edge 42 C is parallel to but offset, as shown in FIG.
- step 320 from a plane that passes through the interior tips (not visible in FIG. 3F ) of the fins 45 .
- step 320 a portion of the flat edge 42 C is pre-welded to consolidate the flattened material and add strength and handleability to the edge 42 C.
- the folded sheet is then refolded in step 325 , as shown in FIG. 3G , and the edges are sealed in step 330 . If the sealing process comprises welding or brazing, the strength and quality of the seal may be improved by inclusion of the pre-weld process step 315 .
- step 335 a flow divider 46 is inserted into the interior volume 44 formed by the sealed, refolded sheet.
- a base element comprising sheets from rolls 90 A, 90 B, and 90 C in the example of FIG. 3C , is then coupled to the perimeter of the opening of the interior volume 44 in step 340 , thereby forming the inlet 36 and outlet 38 and completing the primary surface heat exchange element 32 .
- FIG. 15 is a flowchart 400 for an exemplary manufacturing process for a plate-fin heat exchange element 120 according to certain aspects of this disclosure.
- the flow chart 400 is related to the process equipment shown in FIG. 8A .
- step 405 sheets of material from one or both of rolls 101 A or 101 B are folded to form hollow fins thereby forming one or both of folded sheets 105 and 106 .
- the sheets 105 and 106 are bonded on opposite sides of a center sheet that forms the separation wall 102 to form a heat exchange wall 100 .
- the edges of the separation wall 102 are lifted, or offset, in step 415 that to an offset distance that, in the example of FIG. 8A , is equal to the height of the fins of heat coupling wall 106 .
- the heat exchange wall 100 is then refolded in step 420 , as shown as item 114 in FIG. 8A , and the edges of the separation wall 102 are sealed in step 425 .
- base element (not shown in FIG. 8A ) that is similar to the base element of FIG. 3C is then coupled to the sealed, refolded heat exchange sheet 100 to form a plate-fin heat exchange element 120 .
- the concepts disclosed herein provide a system and method of efficiently transferring heat from a first fluid to a second fluid through heat exchangers that comprise fins in contact with one of the fluids.
- the fins are in contact with the first fluid on one surface and in contact with the second fluid on a second surface opposite the first surface.
- the heat exchangers comprise an internal flow divider configured to cause the internal fluid to flow substantially through interior passages formed by the fins.
- the heat exchangers comprise a separation wall with finned heat coupling walls thermally bonded to one or both sides of the separation wall, thereby increasing the thermal coupling between the fluids and the separation wall by increasing the effective contact area between the fluids and the separation wall.
- top should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference.
- a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference.
- a phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology.
- a disclosure relating to an aspect may apply to all configurations, or one or more configurations.
- a phrase such as an aspect may refer to one or more aspects and vice versa.
- a phrase such as an “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology.
- a disclosure relating to an configuration may apply to all configurations, or one or more configurations.
- a phrase such an configuration may refer to one or more configurations and vice versa.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
A heat exchanger is disclosed that includes heat exchange elements made from a sheet having a plurality of hollow fins. In certain embodiments, the finned sheet is refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening that is opposite the refold of the finned sheet. In certain embodiments, a flow divider is located in the interior volume between the inlet manifold and the outlet manifold with interior tips of the hollow fins in contact with the flow divider. A base element is coupled over the opening of the interior volume, the base element comprising an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.
Description
- This application claims priority to U.S. Provisional Application No. 61/425,840, filed on Dec. 22, 2010, which is incorporated herein by reference.
- 1. Field
- The present disclosure generally relates to systems and methods of transferring heat between fluids and, in particular, heat exchangers configured to transfer heat between continuous flows of two fluids.
- 2. Description of the Related Art
- Industrial processes and consumer products often operate by transferring heat between two fluids. An example is a household refrigerator wherein, in a very simplified view, a circulating coolant absorbs heat from a refrigerated space and then rejects the heat to the ambient air. The heat exchange portions of conventional heat transfer systems typically have fins such as shown in
FIGS. 1A and 1B attached to the tubing carrying the coolant. These types of heat exchangers can be complex to fabricate and have an operational performance limit determined by the surface area of the interior of the tube and the mean path that heat must travel from the fluid to the air. - Tubing having circumferential corrugations is often used to allow metal piping systems to accommodate misalignment and angular offsets.
FIG. 1C depicts a typical flexure tube section, showing the circumferential corrugations. As the corrugations are oriented perpendicular to the flow through the tube, the fluid within the folds of the corrugations may be stagnant or cause significant drag on the fluid flow through this section. - One of the drawbacks of conventional heat exchangers is that the fluid to be cooled is exposed only to a limited surface area, typically the interior surface of a smooth cylindrical tube. Another drawback is the difficulty in attaching fins to the tube carrying the fluid to be cooled to improve the thermal coupling of the tube to the external air. Fins can be formed separately and then placed around the tube, which may not provide a good thermal bond between the fins and the tube, or the fins can be brazed or otherwise thermally bonded to the tube in a secondary operation. Alternately, the heat exchanger can be formed from a thick tube and the fins machined directly into the tube or formed by helically co-extruding fins over a central flow tube, both of which produce good thermal connection between the tube and the fins, but the high cost of these techniques typically limit their use to aerospace applications where the added performance is worth the incremental cost. In addition, the performance of a finned heat exchanger of the type shown in
FIGS. 1A and 1B are limited by the long mean thermal path that heat must travel from the interior wall of the tube through the fins to reach the air or other cooling fluid. - The heat exchange element and heat exchangers disclosed herein overcome the drawbacks of conventional heat exchangers by providing a large surface area in contact with the fluid to be cooled and/or the surface area in contact with the cooling fluid and a short mean distance for heat to travel between two fluids. Heat exchangers comprising the disclosed heat exchange elements may be less expensive to manufacture and may provide superior performance to conventional heat exchangers.
- In certain configurations, a heat exchange element is disclosed that includes a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet. The folded sheet comprises a plurality of hollow fins. The heat exchange element also includes a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold. A plurality of interior tips of the plurality of hollow fins is in contact with the flow divider. The heat exchange element also includes a base element coupled to a perimeter of the opening of the interior volume. The base element comprises an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.
- In certain configurations, a refold heat exchanger for transferring heat from a first fluid to a second fluid is disclosed. The heat exchanger comprises a plurality of heat exchange elements. Each heat exchange element includes a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet. The folded sheet comprises a plurality of hollow fins. Each heat exchange element includes a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold. A plurality of interior tips of the plurality of hollow fins is in contact with the flow divider. Each heat exchange element also includes a base element coupled to a perimeter of the opening of the interior volume. The base element comprises an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively. The first edge of a first heat exchange element is not sealed to the first edge of an adjacent second heat exchange element.
- In certain configurations, a method of forming a heat exchange element is disclosed. The method includes the steps of folding a sheet of material to form hollow fins across a width of the sheet to form a folded sheet, flattening a first edge and a second edge of the folded sheet to respectively form first and second flat edges, lifting a portion of the first flat edge and a portion of the second flat edge, refolding the folded sheet such that a first portion of the folded sheet is proximate to a second portion of the folded sheet to form a refolded sheet, sealing the first flat edge and the second flat edge of the refolded sheet to form an interior volume comprising an inlet manifold adjacent to the first flat edge, an outlet manifold adjacent to the second flat edge, and an opening opposite the refold of the folded sheet, and coupling a base element comprising an inlet and an outlet over the opening such that the inlet and outlet are in fluid communication with the inlet manifold and outlet manifold, respectively.
- The accompanying drawings, which are included to provide further understanding and are incorporated in and constitute a part of this specification, illustrate disclosed configurations and together with the description serve to explain the principles of the disclosed configurations.
-
FIGS. 1A-1B depict conventional heat exchangers. -
FIG. 1C depicts a conventional flexible tubing segment. -
FIGS. 1D and 1E depict a conventional corrugated heat exchanger. -
FIG. 1F depicts a conventional process for manufacturing a corrugated heat exchanger. -
FIG. 2A depicts an exemplary primary surface heat exchanger that comprises a plurality of heat exchange elements according to certain aspects of this disclosure. -
FIG. 2B is a view of the underside of the primary surface heat exchanger ofFIG. 2A according to certain aspects of this disclosure. -
FIGS. 3A-3B depict details of the construction of an exemplary primary surface heat exchange element according to certain aspects of this disclosure. -
FIGS. 3C-3G depict anexemplary manufacturing process 80 for a primary surface heat exchange element according to certain aspects of this disclosure. -
FIGS. 4A-4E depict another configuration of a primary surface heat exchange element according to certain aspects of this disclosure. -
FIGS. 5A-5C depict another configuration of a primary surface heat exchange element according to certain aspects of this disclosure. -
FIG. 6 depicts schematically the flow of the two fluids relative to the primary surface heat exchanger ofFIG. 2A according to certain aspects of this disclosure. -
FIG. 7A depicts two examples of refold heat exchangers formed from primary surface heat exchange elements according to certain aspects of this disclosure. -
FIG. 7B-7C illustrate a first configuration of a primary surface heat exchanger wherein the fins are straight according to certain aspects of this disclosure. -
FIG. 7D-7E illustrate a second configuration of a primary surface heat exchanger wherein the fins are formed with a wave pattern according to certain aspects of this disclosure. -
FIG. 7F depicts the height and base width of a flow path in a conventional corrugated heat exchanger. -
FIG. 7G depicts the height and width of a generally rectangular passage within a fin of a primary surface heat exchange element according to certain aspects of this disclosure. -
FIG. 8A depicts an exemplary fabrication process for an example plate-fin heat exchange element according to certain aspects of this disclosure. -
FIGS. 8B-8C depicts details of the construction of the heat exchange sheet fabricated using the process depicted inFIG. 8A according to certain aspects of this disclosure. -
FIG. 9 is a perspective cut-away view of another example configuration of a plate-fin heat exchanger according to certain aspects of this disclosure. -
FIGS. 10A-10B depicts additional details of the construction of the plate-fin heat exchanger shown inFIG. 9 according to certain aspects of this disclosure. -
FIGS. 11A-11B depicts a heat exchanger comprising primary surface heat exchange elements according to certain aspects of this disclosure. -
FIG. 12A depicts an exemplary heat exchanger system comprising a refold heat exchanger according to certain aspects of this disclosure. -
FIG. 12B depicts the operation of the heat exchange system ofFIG. 12A according to certain aspects of this disclosure. -
FIGS. 13A-13C depict the construction of a large heat exchange system comprising heat exchange elements according to certain aspects of this disclosure. -
FIG. 14 depicts an exemplary manufacturing process for a primary surface heat exchange element according to certain aspects of this disclosure. -
FIG. 15 depicts an exemplary manufacturing process for a plate-fin heat exchange element according to certain aspects of this disclosure. - The following description includes examples of heat exchange elements having a finned wall providing improved thermal coupling between fluids on opposite sides of the wall. Walls of these heat exchangers are folded to form a series of hollow fins having a relatively large height-to-width ratio, compared to conventional heat exchangers, and therefore a larger surface than a circular tube having an equivalent cross-sectional area.
- One general type of the disclosed heat exchange elements, referred to herein as “primary surface” heat exchange elements, is designed such that the fluids are separated by only the thickness of the wall that is formed into a series of hollow fins. The fluid inside the heat exchange element flows primarily through passages within the hollow fins, thereby providing a very short mean thermal path between the fluids. A primary surface heat exchanger is over 11 times more efficient, on a volume basis, than a conventional shell-and-tube heat exchanger. The manufacturing process for a primary surface heat exchange element is easily modified to form fins having different heights, widths, and separations as well as to produce heat exchange elements having a range of widths in the flow direction, thereby allowing the heat transfer characteristics to be easily tailored to particular applications. The use of size-specific tooling is reduced or eliminated, thereby simplifying the manufacturing process and the change-over process for reconfiguring a production line to produce a different size of heat exchange element.
- A second general type of heat exchange element, referred to herein as “plate-fin” heat exchange elements, has a separation wall with finned heat-coupling walls attached and thermally coupled to one or both sides, thereby increasing the surface area exposed to the fluid on that side of the separation wall. As the transfer of heat across the interface from the fluid into the wall is a limiting factor in the efficiency of the heat exchanger, the additional surface area provided by the heat-coupling walls improves the rate of heat transfer. A plate-fin heat exchanger can be over 4 times more efficient, on a volume basis, than a conventional shell-and-tube heat exchanger. Similar to the primary surface heat exchanger, the manufacturing process for a plate-fin heat exchange element is easily modified to provide heat exchange elements over a range of widths, lengths, and fin dimensions to provide a range of performance capabilities.
- Heat exchangers built from either type of heat exchange element are modular and extensible, making it a straightforward activity to provide heat exchanges over a wide range of sizes and capabilities, as is shown herein. The improved performance of primary surface or plate-fin heat exchangers allows a given application to use a heat exchanger that may be an order of magnitude smaller than a conventional device.
- In the following detailed description, numerous specific details are set forth to provide an understanding of the present disclosure. It will be apparent, however, to one ordinarily skilled in the art that configurations of the present disclosure may be practiced without some of the specific details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the disclosure.
- The method and system disclosed herein are presented in terms of counterflow heat exchangers configured to transfer heat from a first fluid to a second fluid. It will be apparent to those of skill in the art that the heat exchange elements disclosed herein may be used in other types of heat exchangers, such as immersion heat exchangers wherein the external fluid is not actively circulated. In addition, the heat exchange elements are presented as being fabricated from sheet metal in a sequential forming process, whereas it will be apparent to those of skill in the art that the disclosed structures can be fabricated from other materials and/or using other techniques, such as extrusion of a plastic material. Nothing in this disclosure should be interpreted, unless specifically stated as such, to limit the application of any method or system disclosed herein to a particular material, form factor, or fabrication process. Other configurations of heat transfer systems are known to those of skill in the art and the application of the components and principles disclosed herein to other systems will be apparent.
-
FIGS. 1A and 1B depictconventional heat exchangers FIG. 1A is a cut-away view of aconventional heat exchanger 10 having acentral tube 12 withradial fins 14 attached to the outside of thetube 12. Thefins 14 can be either individual generally planar fins or one or more spiral fins that are continuous along thetube 12.FIG. 1B depicts aheat exchanger 20 havingfins 14 arranged longitudinally along a smooth-wall tube 12 similar to thetube 12 ofFIG. 1A . -
FIG. 1C depicts a conventionalflexible tubing segment 22. Thetube 15 has a series ofcircumferential corrugations 16 formed in the side wall. Thecircumferential corrugations 16 are provided solely to allow thetube 15 to bend sideways without thetube 15 collapsing or being reduced in cross-sectional area. Thecircumferential corrugations 16 may induce additional flow resistance as the flow path through thetube 15 is perpendicular to thecorrugations 16. -
FIGS. 1D and 1E depict a conventional corrugated heat exchanger disclosed in U.S. Patent Application Publication No. 2005/0217836.FIG. 1D shows acore structure 23 formed from a continuouscorrugated sheet 24 folded in a “Z” pattern withcorrugated cut sheets 25 inserted between each fold. The corrugations of thecontinuous sheet 24 and thecut sheets 25 are both formed in a 45° zig-zag pattern, i.e. alternating straight sections wherein each straight section is at right angles to both adjacent straight sections. Four formedheaders 26 are coupled to the four corners of thecore structure 23 as shown inFIG. 1D . -
FIG. 1E shows an assembled conventional corrugated heat exchanger wherein thecore structure 23 has been coated on the ends and the exposed sides with a sealingcompound 27. The pair ofheaders flow 28 will enter theinlet header 26 at the front of the right side and emerge from theoutlet header 26′ on the right side. As the width of thesheets 25 is the same as the width of thecontinuous sheet 24, there is no internal manifold space at either end. Theflow 28 must zig-zag through the corrugations of thecut sheets 25 and cross-oriented corrugations of thecontinuous sheet 24 to reach the far side of the interior volumes connected to theheader 26. While theflow 28 is shown as a single line that turns corners, inreality flow 28 is a diffuse flow that spreads from the header across and downstream then converges to theoutlet header 26′. Similarly, aseparate flow 29 entering theinlet header 26 at the back of the left will flow in a diffuse pattern through the spaces between thecut sheets 25 and thecontinuous sheet 24 and then exit from theoutlet header 26′ at the front on the left side. - The heat exchanger of
FIGS. 1D and 1E may be complex to manufacture as theheaders core structure 23. In addition, application of the sealingcompound 27 is a complex task and may be difficult to complete without the formation of leaks. Furthermore, while theflows core structure 23, the tortuous path between theinlet header 26 andoutlet header 26′ does not make efficient use of the entire enclosed volume and certain portions of the internal volume, for example, the corners, are likely to be dead spaces. -
FIG. 1F depicts aconventional process 210 disclosed in U.S. Pat. No. 6,915,675 for manufacturing a corrugated heat exchange material. Asheet 211 of a formable material is fed into a pair of matedcorrugating rollers sheet 211. These corrugations are limited in shape to the profiles of non-undercut gear teeth. This limits the aspect ratio, i.e. the ratio of the height of the corrugations to the base width of the corrugations. Aplunger 216 is positioned to extend when the smooth sections of thesheet 211 are positioned under theplunger 216, thereby forming a joined series of corrugated foldedsections 230. -
FIG. 2A depicts an exemplaryrefold heat exchanger 30 that comprises a plurality of primary surfaceheat exchange elements 32 according to certain aspects of this disclosure. In this configuration, theheat exchange elements 32 are formed from a continuous sheet of folded metal, i.e. a sheet having a series of fins formed by folding a smooth sheet, that has been refolded to form thewalls 40 and ends 42 of each of theheat exchange elements 32. The construction of a primary surfaceheat exchange element 32 is discussed in greater detail with respect toFIGS. 3A-3G . -
FIG. 2B is a view of the underside of therefold heat exchanger 30 ofFIG. 2A according to certain aspects of this disclosure. A baseelement comprising panels inlets 36 and anoutlets 38 for all of theheat exchange elements 32. -
FIGS. 3A-3B depict details of the construction of an exemplary primary surfaceheat exchange element 32 according to certain aspects of this disclosure. InFIG. 3A , a portion of thewalls 40 and theend 42 have been removed to make theinterior volume 44 visible and illustrate how aflow divider 46 is positioned within theinterior volume 44. It can be seen how the finned sheet ofwall 40 continues from the bottom edge of both walls in a 180° bend to form awall 40 of adjacent heat exchange elements 32 (not shown) so as to collectively form arefold heat exchanger 30 such as shown inFIG. 2A . -
FIG. 3B is an enlarged view of theend 42 ofheat exchange element 32 illustrating how thefins 45, described in greater detail with respect toFIGS. 3D and 4D , of the twowalls 40 are flattened to formflat edges 42A, 42B that are sealed to each other to form anend 42. In certain configurations, theflat edges 42A, 42B are offset from a plane defined by the interior tips of thefins 45 ofwalls 40. In certain configurations, theflat edges 42A, 42B are welded to each other. In certain configurations, theflat edges 42A, 42B are brazed to each other. In certain configurations, theflat edges 42A, 42B are soldered to each other. In certain configurations, theflat edges 42A, 42B are bonded to each other. -
FIGS. 3C-3G depict anexemplary manufacturing process 80 for a primary surfaceheat exchange element 32 according to certain aspects of this disclosure.FIG. 3C depicts theoverall production line 80 starting withrolls 82 of sheet metal or other formable sheet material, for example a thermoformable plastic. In certain embodiments, the sheet material is metal foil having a thickness in the range of 0.003-0.010 inches. The unformedcontinuous sheet 83A is supplied fromroll 82 into afin folding tool 84 that, in this example, forms the entire width of thesheet 83A into a series of fins thereby producing the foldedsheet 83B. In certain embodiments, the foldedsheet 83B has 20-45 fins per inch. The foldedsheet 83B is passed through a pair of edge formers 86 (only the near former 86 is visible inFIG. 3C and inFIG. 3E ) that flatten the ends of thefins 45 to form aflat edge 42C and form/lift theflat edge 42C along the edge of the foldedsheet 83B to form a formed foldedsheet 83C having an offsetflat edge 42C, as seen inFIG. 3F , along each edge. - The formed folded
sheet 83C is refolded into a continuous series of double-layer panels.FIG. 3G shows the refolding process with the tooling removed for clarity. Subsequent to the refolding process, the adjacent edges of the double-layer panels are sealed (the sealing tool is not shown inFIG. 3C ) to each other, for example by welding, brazing, soldering, adhesive bonding, or other joining technology. In certain embodiments, the free edges of thesheet 83C are pre-welded, i.e. melted to form a bead along the free edge. In certain embodiments, pre-welding is accomplished using a standard welding/heating process, such as an electric arc, tungsten inert gas (TIG) welding, and laser welding. This pre-welding consolidates the flattened portion of the offsetflat edge 42C, adding strength and handleability to thesheet 83C. In certain embodiments, additional material, for example a foil strip, is provided along the edge prior to the pre-welding process and is melted into the bead, thereby further adding stiffness to the edge of thesheet 83C. In embodiments where the edges of the refolded double-layer panels are welded to each other, the quality of the welds are improved by pre-welding the edges. - A base element, in this example continuous sheets of metal provided from
rolls FIG. 3C ) to the underside of the sealed double-layer panels to formpanels FIG. 2B , to form theinlets 36 and outlets 38 (not visible inFIG. 3C but also visible inFIG. 2B ) and produce a continuous series of theheat exchange elements 32. The connected string of primary surface heat exchange elements are segmented (a process not shown inFIG. 3C ) into groups to formrefold heat exchangers 30 or other configurations of refold heat exchangers. In another aspect, theproduction line 80 includes an insertion station (not shown inFIG. 3C ) between the formingtools 88 and the addition of thepanels flow dividers 46 into theinterior space 44 of each double-layer panel. -
FIG. 3D is an enlarged view of the region indicated by the dashed-line box 3D inFIG. 3C . In this example, thesheet 83A is folded intofins 45 having rounded tops and bottoms with aprimary width 92 and asecondary width 94 and afin height 96. In certain examples, the tops and bottom of thefins 45 have non-round profiles. Thewidths widths widths refold heat exchanger 30. In some cases, theheight 96 of thefins 45 may vary along the length ofsheet 83B and in theheat exchangers 32. -
FIG. 3E is an enlarged view of the region indicated by the dashed-line box 3E inFIG. 3C .Sheet 83B having fins formed across the full width of the sheet is fed into the edge-formingtool 86 that flattens, or crushes, the fins along the edge into aflat edge 42C to formsheet 83C. -
FIG. 3F is an enlarged view of the region indicated by the dashed-line box 3F inFIG. 3C showing theflat edge 42C and thecentral fins 45 previously shown inFIGS. 3A and 3B . It can be seen that theflat edge 42C is offset from the bottom of the fins in the central portion of thesheet 83C. - In other aspects of the present disclosure, the
flat sheet 83A can be formed into corrugations across only the center section of the sheet (not shown) leavingflat regions 42C along each edge, thereby eliminating the need to reform a flat edge from a finned profile. The ability to form the configuration ofsheet 83C having fins in the center and flat edges depends at least in part on the material and the thickness of thesheet 83A. - Alternate manufacturing processes can includes stamping (not shown) of metal or plastic sheets to directly form continuous sheets or discrete panels (not shown) having the
fins 45 andflat edges 42C of the formed foldedsheet 83C as well as vacuum forming, pressure forming, or hydroforming (all not shown) of thefins 45 andedges 42C. In some cases, the top edges and/or bottom edges of discrete panels may be joined with header and/or footers (not shown) to formheat exchange elements 32. In some cases, side elements (not shown) may be used in place of the flattenedportions 42C to join the side edges of the discrete double-layer panels. In some cases, a bulk material, such as a thermoset resin, may be molded, such as by compression molding or injection molding, directly into the shape offinned sheet 83C of an appropriate size to formside walls 40 of aheat exchange element 32. -
FIG. 3G is an enlarged view of the region indicated by the dashed-line box 3G inFIG. 3C showing the folding of the formed foldedsheet 83C with the folding tool removed to reveal the forming process. It can be seen how theflat edges 42C of a double-layer panel are positioned proximate to each other prior to being bonded to each other, for example by solder, to form theedge 42 of aheat exchange element 32. This continuous series ofheat exchange elements 32 can be segmented in groups so as to formrefold heat exchangers 30 as are shown inFIG. 7A . -
FIGS. 4A-4E depict a configuration of a primary surfaceheat exchange element 32A according to certain aspects of this disclosure. In this configuration, theflow divider 46 is omitted and theinterior tips 56 offins 45 of the twowalls FIG. 4A is a cut-away side view of theheat exchange element 32A wherein the interior surface ofwall 40A is visible. At each end, theareas 42 that are sealed to thenear wall 40B (removed in this view) are shown as hatchedareas 42 at the left and right edges of thewall 40A. Theadjacent areas ends 42, are smooth-walled volumes that form aninlet manifold 48B and anoutlet manifold 48C. In the middle of theheat exchange element 32A,fins 45 pass from theinlet manifold 48B to theoutlet manifold 48C. The edges ofbottom panels wall 40A. -
FIG. 4B is a cross-section view of a complete primary surfaceheat exchange element 32A taken along thesection line 4B-4B inFIG. 4A . Thewalls heat exchange element 32A separating thewalls inlet manifold 48B. Theseam 42D between theflanges 42A and 42B is visible inFIG. 4B as a vertical line on the interior surface of theend 42. -
FIG. 4C is a cross-section view of a complete primary surfaceheat exchange element 32A taken along thesection line 4C-4C inFIG. 4A . Thefins 45 ofwalls heat exchange element 32A that would be wetted by a fluid contained within theinterior volume 44. It can also be seen how the finnedsheet forming wall 40A folds over in a 180° bend to form a top 43 and then continue as part ofwall 40B. -
FIG. 4D is an enlarged view of the portion ofFIG. 4C enclosed in the dashed-line circle 4D. It can be seen how the series ofhollow fins 45 are formed as a series ofconvex folds 52 that alternate with concave folds 54. The convex andconcave folds 52, 54 are alternately connected by sidewalls 58. Each concave fold 54 has atip 56 on the side facing theinterior volume 44. Eachfin 45 has aninterior passage 44A bounded by theconvex fold 52, the twosidewalls 58A and 58B connected to theconvex fold 52, and a plane connecting thetips concave folds respective sidewalls 58A, 58B. Returning toFIG. 4C , it can be seen how the only flow paths from theinlet manifold 48B to theoutlet manifold 48C are through one ofinterior passages 44A of the plurality offins 45 formed by the finned sheets ofwalls -
FIG. 4E is a cross-section view of a complete primary surfaceheat exchange element 32A taken along thesection line 4E-4E inFIG. 4A . Ends 42 are visible at the left and right sides. The two-step offset in regions of the inlet andoutlet manifold fins 45 when twoheat exchange elements 32A are positioned adjacent to each other with thefins 45 in contact. It can be seen howinterior passages 44A of eitherwall outlet manifold 48C. -
FIGS. 5A-5C depict another configuration of a primary surfaceheat exchange element 32B according to certain aspects of this disclosure.FIG. 5A is a cut-away side view of theheat exchange element 32B wherein theflow divider 46 and the interior surface ofwall 40A is visible. In this configuration, thefins 45 extend from oneend 42 to theother end 42. In this configuration, aflow divider 46 is disposed within theinterior volume 44 between theinlet 36 and theoutlet 38. - The
flow divider 46 functions to force essentially all of the flow of fluid passing from theinlet manifold 48B to theoutlet manifold 48C to flow through thepassages 44A formed within thehollow fins 45, thereby increasing the amount of time that each element of the fluid is within close proximity to awall 45 and thereby improving the heat transfer from the fluid to thewall 45. In certain embodiments, theflow divider 46 comprises a solid portion having two parallel planar solid surfaces, as is shown inFIG. 3A . In certain embodiments, theflow divider 46 comprises a foam material. In certain embodiments, theflow divider 46 comprises a coating over a foam core. In certain embodiments, theflow divider 46 comprises a metal formed into a hollow or solid shape. The flow divider may be formed as any structure that blocks the flow of fluid between theinlet manifold 48B and theoutlet manifold 48C outside of theinterior passages 44A. -
FIG. 5B is a cross-section view of a complete primary surfaceheat exchange element 32B taken along thesection line 5B-5B through the inlet manifold inFIG. 5A . It can be seen how thetips 56 of thewalls flow divider 46, shown as a dashedoutline 46A inFIG. 5B . -
FIG. 5C is a cross-section view of a complete primary surfaceheat exchange element 32B taken along thesection line 5C-5C inFIG. 5A . It can be seen thatflow divider 46 fills theinterior volume 44 and thetips 56 offins 45 contact theflow divider 46. As previously discussed with respect to heatexchange element 32A inFIGS. 4A-4E , it can be seen thatinterior passages 44A of eitherwall outlet manifold 48C. -
FIG. 6 depicts schematically the flow of the twofluids heat exchange element 32 ofFIG. 2A according to certain aspects of this disclosure.FIG. 6 is a cut-away side view ofheat exchange element 32B whereinflow divider 46 and the interior surface offins 45 ofwall 40A are visible. The fluid 50 is in contact with the outside surfaces ofheat exchange element 32 whilefluid 60 is provided at theinlet 36 and removed fromoutlet 38 through external conduit (not shown inFIG. 6 ). The fluid 50 is flowing from right to left, in the view ofFIG. 6 , and is in contact with the external surfaces of thefins 45 of both thevisible wall 40A and the removedwall 40B.Fluid 60 is introduced throughinlet 36 into theinlet manifold 48B which serves to distribute the fluid 60 across the plurality of fins of bothwalls interior passages 44A of the plurality offins 45 and into theoutlet manifold 48C. The presence of the open inlet and outlet manifolds 48B, 48C serve to evenly distribute the flow across all of thepassages 44A, i.e. without a difference in the pressure drop from the inlet to each of theinterior passages 44A, such that the overall performance of the primary surfaceheat exchange element 32B is improved. The fluid in the outlet manifold exits throughoutlet 38. In can be seen that thisheat exchange element 32 has been implemented as part of a counterflow heat exchanger wherein the direction of flow of the fluid 60 within theheat exchange element 32 is opposite the direction of flow of the fluid 50. In certain configurations,fluid 60 is a coolant rejecting heat to thefluid 50. In certain configurations,fluid 50 is a gas. In certain configurations,fluid 50 is ambient air. In certain configurations,fluid 60 is a liquid. -
FIG. 7A depicts two examples 30D and 30E of refold heat exchangers formed fromconfigurations heat exchange elements 32 according to certain aspects of this disclosure. The comparison of the tworefold heat exchangers heat exchange elements 32 can be easily changed according to the needs of a particular application. Likewise, the width of the heat exchange elements, the separation of the heat exchange elements, and the heights and widths of thefins 45 can also be easily varied to adapt the design to particular applications. It can be seen that thefins 45 ofheat exchangers fins 45. This pattern is advantageous to prevent nesting of thefins 45 of adjacentheat exchange elements 32, as is discussed in greater detail with respect toFIGS. 7B and 7C . -
FIG. 7B-7C illustrate a first example configuration of a primary surfaceheat exchange element 32 wherein thefins 45 are straight, i.e. without the wave pattern seen inFIG. 7A , according to certain aspects of this disclosure. InFIG. 7B , thefins 45 of a firstheat exchange element 32 are positioned with the peak of eachfin 45 positioned as indicated by thesolid lines 65. Thefins 45 of a second adjacentheat exchange element 32 are positioned such that the peaks of the fins of the second adjacentheat exchange element 32 are positioned as indicated by the dashed lines 64. If the two sets offins 45 are pressed against each other, thefins 45 of the twoheat exchange elements 32 can become interleaved. -
FIG. 7C is a cross-section of the fin arrangement ofFIG. 7B taken along thesection line 7C-7C.FIG. 7C illustrates how thefins 45 can become nested when thepeaks straight fins 45. This nesting may reduce the efficiency of theheat exchanger 30 and possibly damage theheat exchange elements 32. -
FIG. 7D-7E illustrate a second example configuration of a primary surfaceheat exchange element 32 wherein thefins 45 are formed with a wave pattern as shown inFIG. 7A according to certain aspects of this disclosure. Similarly to the illustration ofFIG. 7B , the peaks of eachfin 45 of a firstheat exchange element 32 are positioned as indicated by thesolid lines 67. The peaks of thefins 45 of the adjacentheat exchange element 32 are positioned as indicated by the dashed lines 66. It can be seen that the wave pattern is reversed and therefore thelines heat exchange element 32. If the two sets offins 45 are pressed against each other, thefins 45 of the twoheat exchange elements 32 cannot become nested. -
FIG. 7E is a cross-section of the fin arrangement ofFIG. 7D taken along thesection line 7E-7E. InFIG. 7E , the location of thefins 45 on the plane of thecross-section 7E-7E are shown in the light shading whereas the portion of thesame fins 45 are shown in dark gray further from the plane of thecross-section plane 7E-7E. It can be seen that the dark portions of thefins 45 that are associated withcurves 66 overlap the dark portions of thefins 45 associated withcurves 67, which is shown inFIG. 7D by the crossing of thelines fins 45 cannot become nested. This reversal of thecurves fins 45 passing overtop 43 of theheat exchange element 32 such that the curves on one side of theheat exchange element 32 are reversed from the curves on the other side of thesame element 32 and theadjacent elements 32. -
FIG. 7F depicts the height H1 and base width W1 of a flow path in a conventional corrugated heat exchanger as seen inFIG. 1D . The triangular corrugations ofcontinuous sheet 24 are perpendicular to the triangular corrugations ofcut sheet 25, creating theflow area 17 at each peak of thecut sheet 25. A height H1 and a base width W1 are defined for thisflow area 17 as shown inFIG. 7F . As the folds ofsheet 24 are approximate right angles, the ratio of H1 to W1 is 0.5. -
FIG. 7G depicts the height H2 and width W2 of a generallyrectangular passage 44A within afin 45 of a primary surfaceheat exchange element 32 according to certain aspects of this disclosure. In certain embodiments, the sides offin 45 are parallel and form a generallyrectangular passage 44A. While the top offin 45 is rounded and the bottom corners are splayed outward as they connect to theadjacent fins 45, the shape of thepassage 44A is still considered to be generally rectangular with a width of W2 and a height of H2. In this example, it can be seen that the ratio of H2 to W2 is greater than 1.0, and may be approximately 4.0 in the example ofFIG. 7G . In certain embodiments, the walls offin 45 may be slightly angled based on resilience of the material of the walls offin 45 or tooling clearances, it may still be considered generally rectangular if the angles are not too severe. If the walls become significantly angled and cannot be considered to form a generallyrectangular passage 44A, then a base width similar to that shown inFIG. 7F is used to evaluate the ratio of thepassage 44A. -
FIG. 8A depicts an exemplary fabrication process for an example plate-finheat exchange element 120 according to certain aspects of this disclosure. In this process, asheet 102 of material, for example aluminum or copper or other metal or metal alloy, is coated on both sides with a brazing material bysprayers rolls tools tools rolls fins 45 across the full widths of the foldedsheets sheets sheet 102 and, in this example, passed through abraze oven 110. In thebraze oven 110, the brazing material previously applied tosheet 102 melts and bonds the threesheets tools 112 that, in this example, form and offset the edges of thecenter sheet 102 into smooth “S” shapes, thereby finishing the fabrication of theheat exchange sheet 100. Additional details of theheat exchange sheet 100 are discussed with respect toFIG. 8B . The continuous sheet ofheat exchange sheet 100 is refolded in operation 114 (the refolding tool is not shown in FIG. 8A0 to form double-layer panels that, when bonded together, form plate-finheat exchange elements 120 that are discussed in greater detail with respect toFIG. 9 . -
FIGS. 8B-8C depict details of the construction of theheat exchange sheet 100 fabricated using the process depicted inFIG. 8A according to certain aspects of this disclosure. In this example, the tips of thefins 45 ofsheets sheet 102 are at least partially brazed to thesheet 102.FIG. 8B is a perspective view of the near edge ofheat exchange sheet 100. It can be seen that the width of the upper foldedsheet 105 is less than the width of thecenter sheet 102 and the portion of thecenter sheet 102 that extends past the foldedsheet 105 is formed into an “S” that, in this configuration, is offset by a distance that is equal to the height of the find formed in the lower foldedsheet 106. It can also be seen that the width of the foldedsheet 106 is less than the width of thefinned sheet 105. In certain embodiments, the foldedsheet 106 is centered onsheets equal spaces 108 are formed at each end. In certain embodiments, the foldedsheet 106 is disposed between the ends ofsheets unequal spaces 108 are formed at each end. Thefins 45 ofsheets -
FIG. 8C is a cross-section end view of theheat exchange sheet 100 at the point along the production line whereFIG. 8B is taken from. In this example, thecenter sheet 102 is formed at each end into the “S” shape and the foldedsheets sheet 102.Spaces sheet 106. -
FIG. 9 is a perspective cut-away view of another example configuration of a plate-finheat exchange element 120 according to certain aspects of this disclosure. In this configuration, theheat exchange sheet 100 is refolded as shown at the end of the process ofFIG. 8A such that the tips of thefins 45 ofsheet 106 are in contact. It can be seen inFIG. 9 that at least some of the tips of the fins ofsheet 106A of afirst sidewall 122A of theheat exchange element 100 are in contact with the tips of thefins 45 ofsheet 106B of asecond sidewall 122B. As theheat exchange sheet 100 is refolded to form theheat exchanger 120, the tips of thefins 45 ofsheets 105A also are in contact with the tips of adjacent fins ofsheets 105B. In certain configurations, thefins 45 ofsheets 105 and/or 106 are formed into the “wave” pattern shown inFIGS. 7A-7C so as to reduce the tendency to nest and thereby maintain the tip-to-tip spacing ofsheets FIG. 9 . Abase element 124 is bonded to the lower folds of theheat exchange element 100 so as to form the sealed interior volume within a single plate-finheat exchange element 120. As shown inFIG. 9 , multipleparallel heat exchangers 120 can be formed from a continuousheat exchange element 100. -
FIGS. 10A-10B depict additional details of the construction of the plate-finheat exchange element 120 shown inFIG. 9 according to certain aspects of this disclosure.FIG. 10A is a cross-section end view of a plate-finheat exchange element 120A and portions of adjacent plate-finheat exchange elements center sheet 102 ofFIG. 8B forms aseparation wall 132 that cooperates with the base element 124 (not visible inFIG. 10A , shown inFIG. 9 ) to form aninterior volume 126 shown as the darker shaded area in this cross-section view. The foldedsheet 106 forms a firstheat coupling wall 136 comprising, in this configuration, a series offins 130 that are similar to thefins 52 of the primary surfaceheat exchange element 32 shown inFIG. 4D . Similarly, the foldedsheet 105 forms a secondheat coupling wall 135 comprising, in this example,fins 130. The tips offins 130 ofheat coupling wall 136 are in contact with the tips offins 130 of the adjacentheat coupling wall 136, and the tips offins 130 ofheat coupling wall 135 ofheat exchange element 120A are in contact with the tips offins 130 of adjacentheat exchange elements first fluid 126A, such as a mixture of propylene glycol and water, fills thevolume 126, including both the interior passages offins 130 and the spaces betweenfins 130. Anexternal volume 128, i.e. the space outside of theseparation wall 102, is filled with asecond fluid 128A, such as air, which fills the interior passages offins 130 of foldedsheet 105 as well as the spaces between thefins 130 ofsheet 105. - In certain embodiments, the
outlet manifold 148C is larger, i.e. longer in the flow direction, than theinlet manifold 148B to accommodate the expansion of the fluid as it gains heat while flowing through thefins 130 ofheat coupling wall 136. This provides a pressure drop across theoutlet manifold 148C that is approximately equal to the pressure drop acrossinlet manifold 148B even though the volume of fluid passing through theoutlet manifold 148C is larger than the volume of fluid passing through theinlet manifold 148B. Similarly, theoutlet 38 may be larger, i.e. longer in the flow direction, than theinlet 36 so as to provide pressure drops that are approximately the same. - In an example where the
first fluid 126A involume 126 is hotter than thesecond fluid 128A involume 128, heat is conducted from thefirst fluid 126A into both theseparation wall 132 directly and into theheat coupling wall 136. As theheat coupling wall 136 is thermally conductive, the heat received from thefirst fluid 126A passes into theseparation wall 132. The presence of theheat coupling wall 136 effectively increases the surface area of theseparation wall 132 in contact with thefirst fluid 126A. When heat transfer across the boundary layer of thefirst fluid 126A that forms on a surface is a limiting factor in heat transfer, theheat coupling wall 136 may improve the overall heat transfer performance of therefold heat exchanger 120. Similarly, theheat coupling wall 135 receives heat from theseparation wall 132 and transfers this heat into thesecond fluid 128A in parallel with the direct transfer of heat from theseparation wall 132 to thesecond fluid 128A. This effectively increases the surface area of theseparation wall 132 and reduces the effect of any boundary layer of thesecond fluid 128A at the surfaces of theheat coupling wall 135 and theseparation wall 132. -
FIG. 10B is a top cross-section view of the plate-finheat exchange element 120A along the dashedline 10B-10B inFIG. 10A . In this view, theinlet manifold 148B andoutlet manifold 148C formed by thespaces 108 ofFIG. 8B in theheat exchange sheet 100 are shown at each end of theheat coupling wall 136 within theseparation walls 132. The “S” shaped portions ofcenter wall 102 have been sealed to each other to formflanges 146 that form a portion of the enclosure ofvolume 126. In the configuration ofFIG. 10B , similar toFIG. 6 , thefirst fluid 126A and thesecond fluid 128A are shown as flowing past and through theheat coupling walls heat exchange element 120A operates as a counterflow heat exchanger. -
FIGS. 11A-11B depicts aheat exchanger 30E comprising primary surfaceheat exchange elements 32E according to certain aspects of this disclosure. In certain embodiments, theheat exchanger 30E comprises plate-finheat exchange elements 120. Theheat exchanger elements 32E are arranged in a radial pattern about acentral opening 31 such that, relating this configuration to the configuration ofFIG. 10A-10B , thesecond fluid 128A passes axially through theheat exchanger 30E, as shown by thearrows 128A, while thefirst fluid 126A is provided throughinlet 36 and received fromoutlet 38 within theopening 31. - It can be seen in
FIG. 11B that each of theheat exchange elements 32E are curved whereas theheat exchange elements heat exchange elements 32E around theinside edge 140 of opening 31 is less than the separation of the sameheat exchange elements 32E at theoutside edge 142 of theheat exchanger 30E. The curved profile of eachheat exchange element 32E increases the length of eachheat exchange element 32E compared to a planar profile arranged in a radial pattern. This fills the entire toroidal-shaped area of the axial cross-section and improves the efficiency, i.e. the heat exchange capability per unit volume, ofheat exchanger 30E compared to a design using radial planar heat exchange elements 32 (not shown). Theheat exchange elements 32E are otherwise substantially the same as theheat exchange element -
FIG. 12A depicts an exemplaryheat exchanger system 150 comprising arefold heat exchanger 30 according to certain aspects of this disclosure. In this configuration, therefold heat exchanger 30 is configured substantially as shown inFIG. 2A , comprising a plurality of primary surfaceheat exchange elements 32. In certain configurations, theheat exchanger 30 comprises plate-finheat exchange elements 120. Theinlet 36 and outlet 38 (not visible inFIG. 12A ) of theheat exchanger 30 are positioned over flow channels in anexternal manifold 158 such thatinlet 160 andoutlet 162 of theexternal manifold 158 are in separate fluid communication withinlet 36 andoutlet 38, respectively. Aflow enclosure 156 is positioned over theheat exchanger 30 with aninlet 164 and an outlet 166 (not visible inFIG. 12A ). -
FIG. 12B depicts the operation of the heat exchange system ofFIG. 12A according to certain aspects of this disclosure. In this example, with reference to the fluids ofFIG. 6 , afirst fluid 60 is initially cooler than asecond fluid 50. The “cool”first fluid 60 is provided at theinlet 160. The “hot”second fluid 50 is provided at theinlet 164 of theflow enclosure 156. In this example, the direction of flow of the first fluid within theheat exchanger 30 is opposite the direction of flow of the second flow past the outside surfaces of theheat exchanger 30. As the second fluid 50 passes through and around theheat exchanger 30, heat is transferred into the material of theheat exchanger 30 and then into thefluid 60. Thus, thefirst fluid 60 received from theoutlet 162 is warmer thanfluid 60 entering theinlet 160 and the fluid 50 leavingoutlet 166 is cooler than the fluid 50 entering theinlet 164. In certain configurations, the first fluid is warmer than the second fluid and the heat transfer is accomplished in the opposite direction, i.e. from thefirst fluid 60 to thesecond fluid 50. -
FIGS. 13A-13B depict the construction of aheat exchange system 200 comprisingheat exchange elements 30 according to certain aspects of this disclosure.FIG. 13A depicts the assembly of twoheat exchangers 30 with anexternal manifold 158A that is a double-sided version of the external manifold ofFIG. 12A to form aheat exchange subassembly 170. Theinlet 160 andoutlet 162 of the double-sidedexternal manifold 158A are separately and respectively coupled to theinlets 36 andoutlets 38 of theindividual heat exchangers 32. Theheat exchange subassembly 170 is an extensible design, i.e. the heat exchange capacity of thesubassembly 170 is a function of the length L and width W and height H of theheat exchangers 30 as well as the number of heat exchangers. In certain implementations, this function is generally linear over a certain range of proportions between L, W, and H. In certain embodiments, thesubassembly 170 comprises primary surfaceheat exchange elements 32. In certain embodiments, thesubassembly 170 comprises plate-finheat exchange elements 120. -
FIG. 13B illustrates a higher-level subassembly 180 comprisingmultiple subassemblies 170 coupled to acenter pipe 181. Thecenter pipe 181 is divided internally intoflow paths openings center pipe 181, wherein theopenings 182 are in fluid communication with theflow path 186 and theopenings 184 are in fluid communication withflow path 188. In this configuration, when thesubassemblies 170 are mated to thecenter pipe 181, theopenings 182 are coupled to theinlets 160 ofsubassemblies 170 and theopenings 184 are coupled to theoutlets 162 such thatflow path 186 is a common inlet to all of thesubassemblies 170 and flowpath 188 likewise a common outlet to all of thesubassemblies 170 coupled to thecenter pipe 181. -
FIG. 13C illustrates the top-levelheat exchanger system 200 comprising a plurality of thesubassemblies 180 ofFIG. 13B identified assubassemblies 180A-180D. In this configuration, the ends ofcenter pipes 181 of the plurality ofsubassemblies 180A-180D are coupled in series such that theinlet flow paths 186 are fluidically coupled and theoutlet flow paths 188 are likewise fluidically coupled. The ends offlow paths system inlet 202 and asystem outlet 204. A first fluid introduced into thesystem inlet 202 will flow through theflow paths 186 of all of thesubassemblies 180A-180D, then flow into theinlets 160 of each of thesubassemblies 170, and then into theinlets 36 of each of theheat exchangers 30. As the first fluid passes through eachheat exchanger 30 and out of theoutlets 38, the first fluid is collected in the flow channels ofexternal manifolds 158A and passes through theoutlets 162 into theflow path 188 of thesubassemblies 180 and then out through thesystem outlet 204. The rear opening of thecenter pipe 181 of thesubassembly 180D can be capped, making the system 200 a stand-alone system, or further connected to anotherheat exchanger system 200. -
FIG. 14 is aflow chart 300 of an exemplary manufacturing process for a primary surfaceheat exchange element 32 according to certain aspects of this disclosure. Theflow chart 300 is related to theprocess equipment 80 shown inFIG. 3C . Instep 305, a sheet ofmaterial 83A having a first edge and a second edge is folded to form a series ofhollow fins 45, an example fin configuration shown inFIG. 3D , thereby forming a foldedsheet 83B. Instep 310, the ends of thefins 45 along the first and second edges are flattened to form aflat edge 42C on each side. Instep 315, the flat edges are lifted, or offset such that theflat edge 42C is parallel to but offset, as shown inFIG. 3F , from a plane that passes through the interior tips (not visible inFIG. 3F ) of thefins 45. Instep 320, a portion of theflat edge 42C is pre-welded to consolidate the flattened material and add strength and handleability to theedge 42C. The folded sheet is then refolded instep 325, as shown inFIG. 3G , and the edges are sealed instep 330. If the sealing process comprises welding or brazing, the strength and quality of the seal may be improved by inclusion of thepre-weld process step 315. Instep 335, aflow divider 46 is inserted into theinterior volume 44 formed by the sealed, refolded sheet. A base element, comprising sheets fromrolls FIG. 3C , is then coupled to the perimeter of the opening of theinterior volume 44 instep 340, thereby forming theinlet 36 andoutlet 38 and completing the primary surfaceheat exchange element 32. -
FIG. 15 is aflowchart 400 for an exemplary manufacturing process for a plate-finheat exchange element 120 according to certain aspects of this disclosure. Theflow chart 400 is related to the process equipment shown inFIG. 8A . Instep 405, sheets of material from one or both ofrolls sheets sheets separation wall 102 to form aheat exchange wall 100. The edges of theseparation wall 102 are lifted, or offset, instep 415 that to an offset distance that, in the example ofFIG. 8A , is equal to the height of the fins ofheat coupling wall 106. Theheat exchange wall 100 is then refolded instep 420, as shown asitem 114 inFIG. 8A , and the edges of theseparation wall 102 are sealed instep 425. As base element (not shown inFIG. 8A ) that is similar to the base element ofFIG. 3C is then coupled to the sealed, refoldedheat exchange sheet 100 to form a plate-finheat exchange element 120. - The concepts disclosed herein provide a system and method of efficiently transferring heat from a first fluid to a second fluid through heat exchangers that comprise fins in contact with one of the fluids. In certain configurations, the fins are in contact with the first fluid on one surface and in contact with the second fluid on a second surface opposite the first surface. In certain configurations, the heat exchangers comprise an internal flow divider configured to cause the internal fluid to flow substantially through interior passages formed by the fins. In certain configurations, the heat exchangers comprise a separation wall with finned heat coupling walls thermally bonded to one or both sides of the separation wall, thereby increasing the thermal coupling between the fluids and the separation wall by increasing the effective contact area between the fluids and the separation wall.
- The previous description is provided to enable a person of ordinary skill in the art to practice the various aspects described herein. While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the terms “a set” and “some” refer to one or more. Headings and subheadings, if any, are used for convenience only and do not limit the disclosure.
- It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged. Some of the steps may be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
- Terms such as “top,” “bottom,” “front,” “rear” and the like as used in this disclosure should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference.
- A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to an configuration may apply to all configurations, or one or more configurations. A phrase such an configuration may refer to one or more configurations and vice versa.
- The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs.
- All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim.
Claims (30)
1. A heat exchange element comprising:
a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet, wherein the folded sheet comprises a plurality of hollow fins;
a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold, wherein a plurality of interior tips of the plurality of hollow fins is in contact with the flow divider; and
a base element coupled to a perimeter of the opening of the interior volume, the base element comprising an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively.
2. The heat exchange element of claim 1 , wherein:
the plurality of hollow fins are pinched along the first edge and the second edge so as to respectively form a first flat edge and a second flat edge; and
the folded sheet is sealed at the first flat edge and the second flat edge to form the interior volume.
3. The heat exchange element of claim 2 , wherein the first and second flat edges are parallel to and offset from a plane through the plurality of interior tips of the plurality of hollow fins.
4. The heat exchange element of claim 2 , wherein the sealing of the first and second flat edges is accomplished by one of the group of welding, brazing, soldering, and crimping.
5. The heat exchange element of claim 1 , wherein:
the flow divider is spaced apart from the first and second edges;
the space within the interior volume between the flow divider and the first edge forms the inlet manifold; and
the space within the interior volume between the flow divider and the second edge forms the outlet manifold.
6. The heat exchange element of claim 5 , wherein:
the flow divider comprises first and second surfaces that are substantially planar and parallel to each other; and
the interior tips of the plurality of hollow fins are in substantially continuous contact with the flow divider over the length of the flow divider.
7. The heat exchange element of claim 6 , wherein:
the plurality of hollow fins and the flow divider form a plurality of isolated passages from the inlet manifold to the outlet manifold; and
substantially all of a flow path from the inlet manifold to the outlet manifold is through the plurality of passages of the fins.
8. The heat exchange element of claim 7 , wherein:
each passage comprises an internal height and an internal base width;
a majority of the plurality of passages have a first height and a first base width; and
a ratio of the first height to the first base width is greater than 0.5.
9. The heat exchange element of claim 8 , wherein the ratio of the first height to the first base width is greater than 1.0.
10. The heat exchange element of claim 9 , wherein the ratio of the first height to the first base width is greater than 2.0.
11. The heat exchange element of claim 9 , wherein:
the hollow fins each comprise a pair of side walls;
the side walls of a majority of the hollow fins are generally parallel to each other, thereby forming a generally rectangular passage having a width; and
the ratio of the height of the rectangular passage to the width of the rectangular passage is greater than 2.0.
12. A refold heat exchanger for transferring heat from a first fluid to a second fluid, the heat exchanger comprising a plurality of heat exchange elements, each heat exchange element comprising:
a folded sheet refolded and sealed at a first edge and a second edge to form an interior volume having an inlet manifold adjacent to the first edge, an outlet manifold adjacent to the second edge, and an opening opposite the refold of the folded sheet, wherein the folded sheet comprises a plurality of hollow fins;
a flow divider disposed in the interior volume between the inlet manifold and the outlet manifold, wherein a plurality of interior tips of the plurality of hollow fins is in contact with the flow divider; and
a base element coupled to a perimeter of the opening of the interior volume, the base element comprising an inlet and an outlet positioned in fluid communication with the inlet manifold and the outlet manifold, respectively,
wherein the first edge of a first heat exchange element is not sealed to the first edge of an adjacent second heat exchange element.
13. The refold heat exchanger of claim 12 , wherein:
the plurality of hollow fins are pinched along the first edge and the second edge so as to respectively form a first flat edge and a second flat edge; and
the first flat edge and the second flat edge are sealed to form the interior volume.
14. The refold heat exchanger of claim 13 , wherein the first and second flat edges are parallel to and offset from a plane through the plurality of interior tips of the plurality of hollow fins.
15. The refold heat exchanger of claim 13 , wherein the sealing of the first and second flat edges is accomplished by one of the group of welding, brazing, soldering, and crimping.
16. The refold heat exchanger of claim 12 , wherein:
the flow divider is spaced apart from the first and second edges;
the space within the interior volume between the flow divider and the first edge forms the inlet manifold; and
the space within the interior volume between the flow divider and the second edge forms the outlet manifold.
17. The refold heat exchanger of claim 16 , wherein:
the flow divider comprises first and second surfaces that are substantially planar and parallel to each other; and
the interior tips of the plurality of hollow fins are in substantially continuous contact with the flow divider over the length of the flow divider.
18. The refold heat exchanger of claim 17 , wherein:
the plurality of hollow fins and the flow divider form a plurality of isolated passages from the inlet manifold to the outlet manifold; and
substantially all of a flow path from the inlet manifold to the outlet manifold is through the plurality of passages of the fins.
19. The refold heat exchanger of claim 18 , wherein:
each passage comprises an internal height and an internal base width;
a majority of the plurality of passages have a first height and a first base width; and
a ratio of the first height to the first base width is greater than 0.5.
20. The refold heat exchanger of claim 19 , wherein the ratio of the first height to the first base width is greater than 1.0.
21. The refold heat exchanger of claim 20 , wherein the ratio of the first height to the first base width is greater than 2.0.
22. The refold heat exchanger of claim 20 , wherein:
the hollow fins each comprise a pair of side walls;
the side walls of a majority of the hollow fins are generally parallel to each other, thereby forming a generally rectangular passage having a width; and
the ratio of the height of the rectangular passage to the width of the rectangular passage is greater than 2.0.
23. A method of forming a heat exchange element, the method comprising the steps of:
folding a sheet of material to form hollow fins across a width of the sheet to form a folded sheet;
flattening a first edge and a second edge of the folded sheet to respectively form first and second flat edges;
lifting a portion of the first flat edge and a portion of the second flat edge;
refolding the folded sheet such that a first portion of the folded sheet is proximate to a second portion of the folded sheet to form a refolded sheet;
sealing the first flat edge and the second flat edge of the refolded sheet to form an interior volume comprising an inlet manifold adjacent to the first flat edge, an outlet manifold adjacent to the second flat edge, and an opening opposite the refold of the folded sheet; and
coupling a base element comprising an inlet and an outlet over the opening such that the inlet and outlet are in fluid communication with the inlet manifold and outlet manifold, respectively.
24. The method claim 23 , wherein the step of sealing is accomplished using a process chosen from the group of welding, brazing, soldering, and crimping.
25. The method claim 23 , wherein the step of coupling is accomplished using a process chosen from the group of welding, soldering, and crimping.
26. The method claim 23 , further comprising the step of:
pre-welding the first flat edge and the second flat edge.
27. The method claim 23 , further comprising the step of:
inserting a flow divider into the interior volume between inlet manifold and the outlet manifold.
28. The method claim 23 , wherein the step of folding comprises forming hollow fins comprising an internal height, an internal base width, and a ratio of the internal height to the internal base width greater than 0.5.
29. The method of claim 28 , wherein the ratio is greater than 1.0.
30. The method of claim 28 , wherein the step of folding comprises forming generally rectangular hollow fins comprising an internal width and a ratio of the internal height to the internal width greater than 2.0.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/335,824 US20120160451A1 (en) | 2010-12-22 | 2011-12-22 | Refold heat exchanger |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201061425840P | 2010-12-22 | 2010-12-22 | |
US13/335,824 US20120160451A1 (en) | 2010-12-22 | 2011-12-22 | Refold heat exchanger |
Publications (1)
Publication Number | Publication Date |
---|---|
US20120160451A1 true US20120160451A1 (en) | 2012-06-28 |
Family
ID=46314491
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/335,824 Abandoned US20120160451A1 (en) | 2010-12-22 | 2011-12-22 | Refold heat exchanger |
Country Status (4)
Country | Link |
---|---|
US (1) | US20120160451A1 (en) |
EP (1) | EP2654983A4 (en) |
RU (2) | RU2635673C1 (en) |
WO (1) | WO2012088466A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150144309A1 (en) * | 2013-03-13 | 2015-05-28 | Brayton Energy, Llc | Flattened Envelope Heat Exchanger |
US20190086160A1 (en) * | 2015-07-29 | 2019-03-21 | Danfoss Micro Channel Heat Exchanger (Jiaxing) Co. | Fin assembly for heat exchanger and heat exchanger having the fin assembly |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2717184C2 (en) * | 2015-10-08 | 2020-03-18 | Линде Акциенгезельшафт | Lamella for plate heat exchanger and method for production thereof |
RU203048U1 (en) * | 2020-09-07 | 2021-03-19 | Семен Александрович Араканцев | UNIVERSAL FLOW HEAT EXCHANGER |
Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2567515A (en) * | 1947-06-26 | 1951-09-11 | Janik Karl | Radiator in central heating installations |
US2953110A (en) * | 1954-01-22 | 1960-09-20 | W J Fraser & Co Ltd | Reciprocally folded sheet metal structures |
US3119446A (en) * | 1959-09-17 | 1964-01-28 | American Thermocatalytic Corp | Heat exchangers |
US3198248A (en) * | 1963-04-10 | 1965-08-03 | Minnesota Mining & Mfg | Corrugated heat transfer exchangers |
US3719227A (en) * | 1969-11-10 | 1973-03-06 | Thermovatic Jenssen S Ab | Plate heat exchanger |
US3759322A (en) * | 1970-10-01 | 1973-09-18 | Linde Ag | Heat exchanger |
US4022050A (en) * | 1975-12-04 | 1977-05-10 | Caterpillar Tractor Co. | Method of manufacturing a heat exchanger steel |
US4352393A (en) * | 1980-09-02 | 1982-10-05 | Caterpillar Tractor Co. | Heat exchanger having a corrugated sheet with staggered transition zones |
US4699209A (en) * | 1986-03-27 | 1987-10-13 | Air Products And Chemicals, Inc. | Heat exchanger design for cryogenic reboiler or condenser service |
US5070607A (en) * | 1989-08-25 | 1991-12-10 | Rolls-Royce Plc | Heat exchange and methods of manufacture thereof |
US6032730A (en) * | 1996-09-12 | 2000-03-07 | Mitsubishi Denki Kabushiki Kaisha | Heat exchanger and method of manufacturing a heat exchanging member of a heat exchanger |
US6076598A (en) * | 1996-09-10 | 2000-06-20 | Mitsubishi Denki Kabushiki Kaisha | Opposed flow heat exchanger |
US6742578B2 (en) * | 2001-04-11 | 2004-06-01 | Toyo Radiator Co., Ltd | Heat exchanger core |
US20040206486A1 (en) * | 2003-04-16 | 2004-10-21 | Catacel Corp. | Heat exchanger |
US7147050B2 (en) * | 2003-10-28 | 2006-12-12 | Capstone Turbine Corporation | Recuperator construction for a gas turbine engine |
US7150099B2 (en) * | 2004-03-30 | 2006-12-19 | Catacel Corp. | Heat exchanger for high-temperature applications |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3860065A (en) * | 1970-04-08 | 1975-01-14 | Trane Co | Distributor for plate type heat exchanger having side headers |
US4384611A (en) * | 1978-05-15 | 1983-05-24 | Hxk Inc. | Heat exchanger |
JP3612826B2 (en) * | 1995-11-29 | 2005-01-19 | 三菱電機株式会社 | Heat exchange element |
RU10862U1 (en) * | 1998-09-08 | 1999-08-16 | Хасанов Рим Музагитович | HEAT EXCHANGE PACKAGE |
FR2806469B1 (en) * | 2000-03-20 | 2002-07-19 | Packinox Sa | METHOD FOR ASSEMBLING THE PLATES OF A BEAM OF PLATES AND BEAM OF PLATES REALIZED BY SUCH A PROCESS |
EP1610081A1 (en) * | 2004-06-25 | 2005-12-28 | Haldor Topsoe A/S | Heat exchange process and heat exchanger |
JP2007051804A (en) * | 2005-08-17 | 2007-03-01 | T Rad Co Ltd | Plate-type heat exchanger |
-
2011
- 2011-12-22 EP EP11851467.8A patent/EP2654983A4/en not_active Withdrawn
- 2011-12-22 RU RU2015144175A patent/RU2635673C1/en not_active IP Right Cessation
- 2011-12-22 US US13/335,824 patent/US20120160451A1/en not_active Abandoned
- 2011-12-22 WO PCT/US2011/066965 patent/WO2012088466A1/en active Application Filing
- 2011-12-22 RU RU2013133855/02A patent/RU2568230C2/en not_active IP Right Cessation
Patent Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2567515A (en) * | 1947-06-26 | 1951-09-11 | Janik Karl | Radiator in central heating installations |
US2953110A (en) * | 1954-01-22 | 1960-09-20 | W J Fraser & Co Ltd | Reciprocally folded sheet metal structures |
US3119446A (en) * | 1959-09-17 | 1964-01-28 | American Thermocatalytic Corp | Heat exchangers |
US3198248A (en) * | 1963-04-10 | 1965-08-03 | Minnesota Mining & Mfg | Corrugated heat transfer exchangers |
US3719227A (en) * | 1969-11-10 | 1973-03-06 | Thermovatic Jenssen S Ab | Plate heat exchanger |
US3759322A (en) * | 1970-10-01 | 1973-09-18 | Linde Ag | Heat exchanger |
US4022050A (en) * | 1975-12-04 | 1977-05-10 | Caterpillar Tractor Co. | Method of manufacturing a heat exchanger steel |
US4352393A (en) * | 1980-09-02 | 1982-10-05 | Caterpillar Tractor Co. | Heat exchanger having a corrugated sheet with staggered transition zones |
US4699209A (en) * | 1986-03-27 | 1987-10-13 | Air Products And Chemicals, Inc. | Heat exchanger design for cryogenic reboiler or condenser service |
US5070607A (en) * | 1989-08-25 | 1991-12-10 | Rolls-Royce Plc | Heat exchange and methods of manufacture thereof |
US6076598A (en) * | 1996-09-10 | 2000-06-20 | Mitsubishi Denki Kabushiki Kaisha | Opposed flow heat exchanger |
US6032730A (en) * | 1996-09-12 | 2000-03-07 | Mitsubishi Denki Kabushiki Kaisha | Heat exchanger and method of manufacturing a heat exchanging member of a heat exchanger |
US6742578B2 (en) * | 2001-04-11 | 2004-06-01 | Toyo Radiator Co., Ltd | Heat exchanger core |
US20040206486A1 (en) * | 2003-04-16 | 2004-10-21 | Catacel Corp. | Heat exchanger |
US7147050B2 (en) * | 2003-10-28 | 2006-12-12 | Capstone Turbine Corporation | Recuperator construction for a gas turbine engine |
US7150099B2 (en) * | 2004-03-30 | 2006-12-19 | Catacel Corp. | Heat exchanger for high-temperature applications |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150144309A1 (en) * | 2013-03-13 | 2015-05-28 | Brayton Energy, Llc | Flattened Envelope Heat Exchanger |
US20190086160A1 (en) * | 2015-07-29 | 2019-03-21 | Danfoss Micro Channel Heat Exchanger (Jiaxing) Co. | Fin assembly for heat exchanger and heat exchanger having the fin assembly |
US10816278B2 (en) * | 2015-07-29 | 2020-10-27 | Danfoss Micro Channel Heat Exchanger (Jiaxing) Co. Ltd. | Fin assembly for heat exchanger and heat exchanger having the fin assembly |
Also Published As
Publication number | Publication date |
---|---|
WO2012088466A1 (en) | 2012-06-28 |
RU2635673C1 (en) | 2017-11-15 |
EP2654983A1 (en) | 2013-10-30 |
RU2568230C2 (en) | 2015-11-10 |
RU2013133855A (en) | 2015-01-27 |
EP2654983A4 (en) | 2018-04-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5353868A (en) | Integral tube and strip fin heat exchanger circuit | |
EP1976662B1 (en) | Flat tube, flat tube heat exchanger, and method of manufacturing same | |
EP1243884B1 (en) | Heat exchanger tube | |
US8661676B2 (en) | Rotary die forming process and apparatus for fabricating multi-port tubes | |
EP0859209A1 (en) | Heat exchanger | |
US20120160451A1 (en) | Refold heat exchanger | |
WO2010084889A1 (en) | Heat exchanger and hot water supply apparatus of heat pump type eqipped with same | |
US20040069472A1 (en) | Heat exchanger | |
EP2676094B1 (en) | Method of producing a heat exchanger and a heat exchanger | |
MX2014006544A (en) | Inner fin. | |
WO2012104383A1 (en) | A heat exchanger comprising a tubular element and a heat transfer element | |
JPH07280484A (en) | Stacked type heat exchanger | |
JP2017537795A (en) | Multi-hole extrusion tube design | |
US7690114B2 (en) | Tube having reinforcing structures made of profile rolled metal and method of producing same | |
WO2014139001A1 (en) | Heat exchanger with jointed frame | |
EP2670542B1 (en) | Method of fabricating a double-nosed tube for a heat exchanger | |
JPH11142087A (en) | Heat-exchanger | |
JPH10111086A (en) | Heat exchanger | |
JP2009074772A (en) | Heat exchanger | |
CN108225088A (en) | A kind of flat tube and the heat exchanger using the flat tube | |
US20050279488A1 (en) | Multiple-channel conduit with separate wall elements | |
CN208983916U (en) | One chip folds flat tube and heat exchanger | |
JP2003130566A (en) | Flat tube for heat exchanger and heat exchanger using it | |
CN207991353U (en) | A kind of flat tube and the heat exchanger using the flat tube | |
JP2010107147A (en) | Heat exchanger and method of manufacturing the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: FLEXENERGY ENERGY SYSTEMS, INC., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MANTER, GARY G.;FINSTAD, BRIAN R.;STAMENOV, TONI H.;REEL/FRAME:027443/0093 Effective date: 20111221 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |