Patent Publication Number: US-2022214076-A1

Title: Multi-flue heat exchanger assembly with baffle insert

Description:
FIELD OF THE DISCLOSURE 
     The present invention relates generally to fuel-fired fluid heating devices, and more particularly, to a baffle for inserting into a heat exchanger tube of a fuel-fired heating device for improved heat transfer. 
     BACKGROUND 
     Traditional fuel-fired fluid heating devices can include a tank configured to store fluid and a combustion chamber positioned beneath the tank. A gas burner can be disposed within the combustion chamber. Combustion of fuel and air within the combustion chamber can provide a primary source of heat for the fluid within the tank. In order to dispose of hot combustion gases produced from the combustion of the fuel and air, traditional fuel-fired fluid heating devices can have a central flue pipe extending upwards from the combustion chamber through the tank and outwards from the housing around the tank. The hot combustion gases can flow upwardly through the flue pipe, thereby providing a secondary source of heat. However, this secondary source of heat can be relatively inefficient when the fuel-fired heating device is equipped with only a single, central flue pipe, as heat transfer from the hot combustion gases flowing upwardly through the central flue pipe to the fluid within the tank that is farthest from the central flue pipe can be minimal. 
     Additionally, the hot combustion gases can flow upwardly through the flue pipe in a natural laminar flow path. Without any form of interruption of the natural laminar flow path, the residence time of the hot combustion gases within the flue pipe can be relatively short. Accordingly, baffles and/or baffle arrangements can be inserted into a flue pipe to interrupt the natural laminar flow of the hot combustion gases, thereby providing an increase in residence time, and thus, improved heat transfer to fluid within the tank. However, some of the known baffles and/or baffle arrangements can require welding of individual parts which can undesirably add to the overall cost of the fuel-fired fluid heating devices and complicate manufacturing. Further, some of the known baffles and/or baffle arrangements can impose an undesirable high pressure drop across a height of the flue pipe, thereby potentially causing a dangerous buildup of carbon dioxide in the ambient environment surrounding the fuel-fired fluid heating device. 
     SUMMARY 
     These and other problems can be addressed by the technologies described herein. Examples of the present disclosure relate generally to a heat exchanger assembly including a plurality of heat exchanger tubes and a baffle for inserting into each heat exchanger tube. 
     The disclosed technology can include a heat exchanger tube having a baffle. The baffle can have a first end and a second end, a length of the baffle being defined as a distance between the first end and the second end; a body having a first side and a second side opposite the first side, the body having a first width; a hanging portion located proximate the second end, the hanging portion having a second width that is greater than the first width; and a plurality of fins disposed along the body. Each fin of the plurality of fins can extend outwardly from the body and upwardly towards the second end at an angle relative to a central axis of the body. A first fin of the plurality of fins can be positioned proximate the first end and can have a first angle. A second fin of the plurality of fins can be positioned proximate the second end and can have a second angle. The first angle can be less than the second angle. 
     Each fin of the plurality of fins can be spaced apart from an adjacent fin by a predetermined distance of between approximately 0.75 inches and approximately 1.25 inches. 
     Each fin of the plurality of fins can have a substantially semi-circular cross-section shape. 
     Each fin of the plurality of fins can have a substantially quarter-circular cross-section shape. 
     Each fin of the plurality of fins can have the same cross-section area and the same cross-section shape. 
     The angle at which each fin of the plurality of fins is disposed can progressively increase as the plurality of fins extend along the length of the baffle from the first fin to the second fin. 
     The angle at which the first fin can be between approximately 20 degrees and approximately 35 degrees and the second angle can be between approximately 50 degrees and approximately 65 degrees. 
     The plurality of fins can include a first portion and a second portion. The angle at which each fin of the first portion is disposed can be less than the angle at which each fin of the second portion is disposed, where the first portion can be proximate to the first end and the second portion can be proximate to the second end. 
     The plurality of fins can include a first portion, a second portion, and a third portion. The angle at which each fin of the first portion is disposed can be less than the angle at which each fin of the second portion and the third portion is disposed. The angle at which each fin of the third portion is disposed can be greater than the angle at which each fin of the first portion and the second portion is disposed. The first portion can be proximate to the first end, the second portion can be between the first portion and the third portion, and the third portion can be proximate to the second end. 
     The plurality of fins can include between approximately 6 and approximately 20 fins. 
     The disclosed technology can further include a fluid heating device including a tank having an inlet for delivering fluid into the tank and an outlet for outputting heated fluid from the tank; a combustion chamber in thermal communication with the tank, the combustion chamber having a burner disposed therein; and a heat exchanger assembly including a plurality of heat exchanger tubes. Each heat exchanger tube can be in fluid communication with the combustion chamber and extend through the tank. Each heat exchanger tube can include a baffle including a first end and a second end, a length of the baffle being defined as a distance between the first end and the second end; a body having a first side and a second side opposite the first side, the body having a first width; a hanging portion located proximate the second end, the hanging portion having a second width that is greater than the first width; and a plurality of fins disposed along the body. Each fin of the plurality of fins can extend outwardly from the body and upwardly towards the second end at an angle relative to a central axis of the body. A first fin of the plurality of fins can be positioned proximate the first end and can have a first angle. A second fin of the plurality of fins can be positioned proximate the second end and can have a second angle. The first angle can be less than the second angle. 
     The plurality of heat exchanger tubes can include between approximately 2 and approximately 20 heat exchanger tubes. 
     Each baffle can extend a majority of a length of each heat exchanger tube. 
     Each heat exchanger tube can have an inner diameter, the inner diameter being less than the second width of the hanging portion. 
     Each fin of the plurality of fins can have the same cross-section area and the same cross-section shape. 
     The angle at which each fin is disposed can progressively increase as the plurality of fins extend along the length of the baffle from the first fin to the second fin. 
     The first angle can be between approximately 20 degrees and approximately 35 degrees and the second angle can be between approximately 50 degrees and approximately 65 degrees. 
     The disclosed technology can further include a method of manufacturing a baffle for inserting into a heat exchanger tube. The method can include providing a sheet of metal having a first side and a second side and extending a length from a first end to a second end; penetrating the sheet of metal to form a plurality of fins disposed on at least a portion of the length; and bending each fin of the plurality of fins outward at an angle relative to a central axis of the sheet of metal. 
     Bending each fin of the plurality of fins outward at the angle relative to the central axis of the sheet of metal can include bending a first fin outwards from the first side of the sheet of metal and bending an adjacent fin outwards from the second side of the sheet of metal. 
     The method can further include bending a fin proximate to the first end of the sheet of metal at a first angle and bending a fin proximate the second end of the sheet of metal at a second angle, the first angle being less than the second angle. 
     These and other aspects of the present disclosure are described in the Detailed Description below and the accompanying figures. Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art upon reviewing the following description of specific examples of the present disclosure in concert with the figures. While features of the present disclosure may be discussed relative to certain examples and figures, all examples of the present disclosure can include one or more of the features discussed herein. Further, while one or more examples may be discussed as having certain advantageous features, one or more of such features may also be used with the various other examples of the disclosure discussed herein. In similar fashion, while examples may be discussed below as devices, systems, or methods, it is to be understood that such examples can be implemented in various devices, systems, and methods of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Reference will now be made to the accompanying figures, which are not necessarily drawn to scale, and wherein: 
         FIGS. 1A and 1B  illustrate cross-sectional views of a fuel-fired fluid heating device including an example heat exchanger assembly, in accordance with the disclosed technology; 
         FIG. 2  illustrates an example heat exchanger assembly, in accordance with the disclosed technology; 
         FIGS. 3A and 3B  illustrate top views of example heat exchanger assemblies, in accordance with the disclosed technology; 
         FIG. 4A  illustrates a front view of an example baffle, in accordance with the disclosed technology; 
         FIG. 4B  illustrates a side view of an example baffle, in accordance with the disclosed technology; 
         FIG. 4C  illustrates a perspective view of a portion of an example baffle, in accordance with the disclosed technology; 
         FIGS. 5A-5C  illustrate various design configurations of a fin, in accordance with the disclosed technology; and 
         FIG. 6  is a flow diagram outlining an example method of manufacturing an example baffle, in accordance with the disclosed technology. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed technology includes a heat exchanger assembly having a plurality of heat exchanger tubes. One, some, or all of the heat exchanger tubes can include a baffle. The baffle can include a body having a first side and a second side opposite the first side. The baffle can include a plurality of fins disposed along the length of the baffle. Each fin can be disposed outwardly from each side of the baffle and upwardly at an angle relative to a central axis of the body. The angle at which each fin of the plurality of fins is disposed can progressively and/or incrementally increase as the plurality of fins extend along the length of the baffle. The plurality of fins can result in increased residence time of the hot combustion gases flowing through each heat exchanger tube as compared to heat exchanger assemblies in the prior art, thereby promoting efficient heat transfer and heating of the fluid in the tank. 
     The disclosed technology will be described more fully hereinafter with reference to the accompanying drawings. This disclosed technology can, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. The components described hereinafter as making up various elements of the disclosed technology are intended to be illustrative and not restrictive. Such other components not described herein may include, but are not limited to, for example, components developed after development of the disclosed technology. 
     In the following description, numerous specific details are set forth. But it is to be understood that examples of the disclosed technology can be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description. References to “one embodiment,” “an embodiment,” “example embodiment,” “some embodiments,” “certain embodiments,” “various embodiments,” “one example,” “an example,” “some examples,” “certain examples,” “various examples,” etc., indicate that the embodiment(s) and/or example(s) of the disclosed technology so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase “in one embodiment” or the like does not necessarily refer to the same embodiment, example, or implementation, although it may. 
     Throughout the specification and the claims, the following terms take at least the meanings explicitly associated herein, unless the context clearly dictates otherwise. The term “or” is intended to mean an inclusive “or.” Further, the terms “a,” “an,” and “the” are intended to mean one or more unless specified otherwise or clear from the context to be directed to a singular form. 
     Unless otherwise specified, the use of the ordinal adjectives “first,” “second,” “third,” etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described should be in a given sequence, either temporally, spatially, in ranking, or in any other manner. 
     Unless otherwise specified, all ranges disclosed herein are inclusive of stated end points, as well as all intermediate values. By way of example, a range described as being “from approximately 2 to approximately 4” includes the values 2 and 4 and all intermediate values within the range. Likewise, the expression that a property “can be in a range from approximately 2 to approximately 4” (or “can be in a range from 2 to 4”) means that the property can be approximately 2, can be approximately 4, or can be any value therebetween. Further, the expression that a property “can be between approximately 2 and approximately 4” is also inclusive of the endpoints, meaning that the property can be approximately 2, can be approximately 4, or can be any value therebetween. 
     Unless otherwise specified, the terms liquid and/or water disclosed herein are inclusive of pure water (H 2 O) and pure water plus any additives or additional component. Further, while the disclosed technology is referenced as be useful for water applications, it is to be understood that the disclosed technology can be used for any fluid, liquid, or otherwise. 
     Referring now to the figures,  FIGS. 1A and 1B  illustrate cross-sectional views of a fluid heating device  100  having an example heat exchanger assembly  102 , as further discussed herein. The fluid heating device  100  can be a fuel-fired fluid heating device. The fluid heating device  100  can include an outer shell  104 . The outer shell  104  can include any insulating metal(s) or other material and can be any shape. By way of example, the outer shell  104  can be substantially cylindrical. The fluid heating device  100  can include a tank  106  enclosed within the outer shell  104 . A layer of insulation can be disposed between the outer wall of the tank  106  and an inner wall of the outer shell  104 . Optionally, the layer of insulation can include polyurethane foam. The tank  106  can have substantially the same shape as the outer shell  104 . By way of example, the tank  106  can be substantially cylindrical. The tank  106  can be configured to hold a predefined quantity of water. By way of example, the tank  106  can be configured to hold between approximately 2.5 gallons and approximately 100 gallons of water. In one example, the tank  106  is configured to hold approximately 2.5 gallons of water. In another example, the tank  106  is configured to hold approximately 5 gallons of water. In configurations in which the tank  106  is configured to hold between approximately 2.5 gallons and approximately 5 gallons of water, the fluid heating device  100  can provide heated water substantially instantaneously. The tank  106  can include an inlet  108  and an outlet  110  configured to output heated water. The inlet  108  can extend through the outer shell  104  and open into the tank  106  to deliver unheated water. The outlet  110  can extend through the outer shell  104  from the tank  106  to output heated water. The inlet  108  and the outlet  110  can be tubular pipes with external fittings for connecting plumbing components to a typical pressurized home or commercial plumbing system. 
     The fluid heating device  100  can include a combustion chamber  112  enclosed within the outer shell  104 . The combustion chamber  112  can be disposed below the tank  106 . A burner  114  can be disposed within the combustion chamber  112 . In one example, the burner  114  can include a main fuel-fired burner and a pilot burner. As illustrated in  FIG. 1B , the burner  114  can be in communication with a gas control assembly  128 . The gas control assembly  128  can be in communication with a gas control valve. The gas control valve can be configured to control the flow of gas to the burner  114  via a gas supply line (e.g., a natural gas or propane gas supply line) in response to the temperature of fluid within the tank  106  dropping below a predetermined threshold temperature. Combustion can occur upon the mixture of air and gas at the burner  114 , thereby providing a primary means of heat transfer to the fluid within the tank  106 . 
     The fluid heating device  100  can include the heat exchanger assembly  102  as further discussed herein. The heat exchanger assembly  102  can be in fluid communication with the combustion chamber  112 . The heat exchanger assembly  102  can be in fluid communication with a vent  120 . The heat exchanger assembly  102  can include a plurality of heat exchanger tubes  122  extending through the tank  106 . Each heat exchanger tube  122  can have an open end at each end such that the heat exchanger tube  122  can be configured to direct the hot combustion gases from the combustion chamber  112 , through the heat exchanger tube  122 , and out of fluid heating device  100  via the vent  120 . 
     One, some, or all of the heat exchanger tubes  122  can include a baffle  124  as further discussed herein. As illustrated in  FIGS. 1A and 1B , the baffle  124  can extend substantially the length of the heat exchanger tube  122 . The baffle  124  can include a plurality of fins  126  protruding outwardly from each lateral side of the baffle  124  and upwardly towards the open end of the heat exchanger tube  122  that is in fluid communication with the vent  120 . The plurality of fins  126  can promote efficient heat transfer as the hot combustion gases flow upwardly through the heat exchanger tube  122  by increasing the residence time of the hot combustion gases flowing through the heat exchanger tubes  122 . 
     The fluid heating device  100  can have any dimensions. The dimensions can vary depending on the quantity of water the tank  106  is configured to hold. By way of example, when the tank  106  is configured to hold approximately 2.5 gallons of water, the height H of the fluid heating device  100  can be between approximately 8 inches and approximately 12 inches. When the tank  106  is configured to hold approximately 5 gallons of water, the height H of the fluid heating device  100  can be between approximately 10 inches and approximately 14 inches. The diameter D of the fluid heating device  100  can similarly vary depending on the quantity of water the tank  106  is configured to hold. By way of example, when the tank  106  is configured to hold between approximately 2.5 gallons and approximately 5 gallons of water, the diameter D can be between approximately 8 inches and approximately 12 inches. Accordingly, the size of the fluid heating device  100  can be smaller compared to other traditional fluid heating devices. Such smaller size of the fluid heating device  100  can facilitate providing efficient heating of water. 
       FIG. 2  illustrates a perspective view of the heat exchanger assembly  102 . The heat exchanger assembly  102  can include a first end  202  and a second end  204 . The first end  202  and the second end  204  can be metal plates having substantially the same cross-section shape as the cross-section shape of the tank  106 . By way of example, the first end  202  and the second end  204  can have a substantially disc shape, and thereby, a substantially circular cross-section. The first end  202  and the second end  204  can each include a plurality of apertures  206 . Each aperture  206  can be configured to receive a heat exchanger tube  122 . The first end  202  can be in fluid communication with the combustion chamber  112  while the second end  204  can be in fluid communication with the vent  120 . In such configuration, the hot combustion gases can flow through the heat exchanger tubes  122  and be exhausted out of the fluid heating device  100  via the vent  120 . The second end  204  can include one or more couplings  208   a ,  208   b  configured to receive fittings for the inlet  108  and outlet  110 , respectively. The second end  204  can further include a coupling  210  configured to receive an anode. The anode can extend from the second end  204  into the water within the tank  106 . The anode can provide cathodic protection to protect the tank  106  from corrosion, thereby extending the lifespan of the tank  106 , and thus, the fluid heating device  100 . 
     As illustrated in  FIG. 2 , the heat exchanger tubes  122  can be substantially tubular with open ends on each side. The heat exchanger tubes  122  can be made out of one or more thermally conductive metals to promote heat transfer as the hot combustion gases flow upwardly through the heat exchanger tubes  122  from the combustion chamber  112  to the exterior of the fluid heating device  100  via the vent  120 . The heat exchanger tubes  122  can have any length. Optionally, the length of the heat exchanger tubes  122  can depend on the height H of the fluid heating device  100  and/or the size of the tank  106 . The length of each heat exchanger tube  122  can be approximately a height of the tank  106 . The length of the heat exchanger tube  122  can be slightly greater than the height of the tank  106 . By way of example, the length of the heat exchanger tube  122  can be approximately 0.5 inches greater than the height of the tank  106 . This excess length of the heat exchanger tube  122  can be approximately equally distributed between both ends of the heat exchanger tube  122  when inserted into the apertures  206  of the first end  202  and the respective apertures at the second end  204  of the heat exchanger assembly  102 . In such a configuration, the heat exchanger tube  122  can be properly secured (e.g., via welding). Each heat exchanger tube  122  can have any size inner diameter ID. By way of example, each heat exchanger tube  122  can have an inner diameter ID of between approximately 0.5 inches and approximately 3 inches. 
       FIG. 3A  illustrates a top view of the heat exchanger assembly  102 . The second end  204  of the heat exchanger assembly  102  can include seven apertures  206 , each aperture  206  configured to receive a heat exchanger tube  122 . The heat exchanger tubes  122  can be arranged in any pattern and/or configuration. By way of example, as illustrated in  FIG. 3A , the heat exchanger tubes  122  can be arranged such that there is a central heat exchanger tube extending through a center of the tank  106  and the remaining tubes are arranged in a circular pattern around the central heat exchanger tube. 
       FIG. 3B  illustrates a top view of an alternative heat exchanger assembly  102  having a different number of heat exchanger tubes  122  arranged in a different configuration as compared to the heat exchanger assembly illustrated in  FIG. 3A . The heat exchanger tubes  122  can be arranged in one or more linear rows. As illustrated in  FIG. 3B , the heat exchanger tubes  122  can be arranged in three linear rows, where the center row has three heat exchanger tubes  122  and the first row and the third row have four heat exchanger tubes  122 . 
     Although  FIGS. 2 through 3B  illustrate various configurations of the heat exchanger tubes  122  of the heat exchanger assembly  102 , it is contemplated that the heat exchanger assembly  102  can include any number of heat exchanger tubes  122  arranged in any configuration. By way of example, the heat exchanger assembly  102  can include between 2 and approximately 20 heat exchanger tubes  122 . The number of heat exchanger tubes  122  can depend on the size of the tank  106 . A tank  106  configured to hold a greater amount of fluid can have more heat exchanger tubes  122  than a tank  106  configured to hold less amount of fluid. By way of example, a tank  106  configured to hold approximately 5 gallons of fluid can include a greater number of heat exchanger tubes  122  than a tank  106  configured to hold 2.5 gallons of fluid. Additionally, the heat exchanger tubes  122  can be arranged in a substantially symmetrical pattern, as illustrated in  FIGS. 2 through 3B . Alternatively, the heat exchanger tubes  122  can be randomly oriented. 
     The hot combustion gases flowing through the heat exchanger assembly  102  can provide an additional source of heat transfer to the fluid contained within the tank  106 , apart from the primary source of heat transfer generated from the combustion itself. Because the heat exchanger assembly  102  includes the plurality of heat exchanger tubes  122  as compared to fuel-fired fluid heating devices in the prior art only including a single, central flue pipe, the heat exchanger assembly  102  can provide improved heat transfer, and thus, more efficient heating of the fluid within the tank  106 . In particular, the plurality of heat exchanger tubes  122  provide a multitude of channels in which the hot combustion gases can flow such that a greater volume of fluid within the tank  106  can absorb heat from the hot combustion gases. Accordingly, the fluid within the tank  106  can become heated to the predetermined set temperature at a faster rate as compared to fuel-fired fluid heating devices in the prior art. 
       FIGS. 4A-4C  illustrate the example baffle  124  disposed within each heat exchanger tube  122  of the heat exchanger assembly  102 .  FIG. 4A  illustrates a front view of the baffle  124 , while  FIG. 4B  illustrates a side view of the baffle  124 .  FIG. 4C  illustrates a perspective view of a portion of the baffle  124 . Referring collectively to  FIGS. 4A-4C , the baffle  124  can include a body  402  having two opposing lateral sides  408   a ,  408   b . The body  402  can be a unitary sheet of metal(s) and can have any shape. Optionally, the body  402  can have a substantially rectangular cross-section. Optionally, the body  402  can have a substantially elongated ovular cross-section. The body  402  of the baffle  124  can have a width W 1  of any size. By way of example, the body  402  can have a width W 1  of between approximately 1 inch and 2 inches. The baffle can extend a length L from a first end  404  to a second end  406 . The length L of the baffle  124  can be approximately equal to the length of the heat exchanger tube  122 . Optionally, the length L of the baffle  124  can be only a portion of the length of the heat exchanger tube  122 . By way of example, the length L of the baffle  124  can be approximately equal to half of the length of the heat exchanger tube  122 . The first end  404  can extend proximate to the open end of the heat exchanger tube  122  that is in fluid communication with the combustion chamber  112 . The second end  406  can extend proximate to the open end of the heat exchanger tube  122  that is in fluid communication with the vent  120 . As illustrated in  FIG. 4A , the second end  406  can be or include a hanging end  410 . The hanging end  410  can include two protrusions extending in the width direction of the body such that the width W 2  of the hanging end  410  is greater than the width W 1  of the body  402 . While the body  402  has a width W 1  that is less than the inner diameter ID of the heat exchanger tube  122 , the hanging end  410  of the baffle  124  has a width W 2  (e.g., a diameter) that is greater than the inner diameter ID of the heat exchanger tube  122 . Accordingly, when the body  402  of the baffle  124  is inserted into the heat exchanger tube  122 , the protrusions of the hanging end  410  can abut a top surface at the mouth of the heat exchanger tube  122 , thereby suspending the body  402  of the baffle  124  at a constant location and/or position within the heat exchanger tube  122 . 
     The baffle  124  can include a plurality of fins  126 . The plurality of fins  126  can extend along the length L of the baffle  124  and along each opposing lateral side  408   a ,  408   b  of the body  402 . The plurality of fins  126  can extend outwardly from each lateral side  408   a ,  408   b  of the body  402  and upwardly toward the second end  406  at an angle  414  relative to a central axis A of the body  402 . As illustrated in  FIGS. 4B and 4C , the plurality of fins  126  can extend outwardly and upwardly toward the second end  406  in an alternating manner. In this configuration, a first fin can extend outwardly and upwardly from a first lateral side  408   a  and the adjacent fin (e.g., the fin positioned directly above and/or below the first fin) can extend outwardly and upwardly from a second lateral side  408   b . Such configuration can allow the body  402  to include a greater number of fins  126  as compared to baffles in the prior art, as alternating the direction in which the adjacent fins extend outward can allow adjacent fins to be spaced relatively close together. 
     Each fin  126  can be spaced apart from each adjacent fin (e.g., the fin positioned directly above and/or below) by a predetermined distance  416 . The predetermined distance  416  can be the distance from a base (e.g., straight edge)  418  of a first fin from the base  418  of an adjacent fin. By way of example, each fin  126  can be spaced apart from each adjacent fin by a predetermined distance  416  of between approximately 0.75 inches and approximately 1.25 inches. In one example, each fin  126  can be spaced apart from each adjacent fin by a predetermined distance  416  of approximately 1 inch. Each fin  126  can be spaced apart from each adjacent fin by the same predetermined distance  416 . Alternatively, the fins  126  can be spaced apart from adjacent fins by varying predetermined distances  416 . 
     The angle  414  at which each fin  126  is disposed can vary as the fins  126  extend along the length L of the baffle  124  from the first end  404  to the second end  406 . The angle  414  can progressively and/or incrementally increase as the fins  126  extend from the first end  404  to the second end  406 . In such configuration the fin located closest to the first end  404  can be positioned at the smallest angle while the fin located closest to the second end  406  can be positioned at the largest angle. 
     The plurality of fins  126  can be subdivided into a plurality of portions  412 . The plurality of fins  126  can be subdivided into any number of portions  412 , and each portion can include any number of fins  126  (e.g., one or more fins  126 ). As illustrated in  FIG. 4B , the plurality of fins  126  can be subdivided into a first portion  412   a , a second portion  410   b , and a third portion  412   c . The first portion  412   a  of the plurality of fins  126  can include fins  126  that are each positioned at a first angle  414   a  and are located proximate to the first end  404  of the body  402  (e.g., the first portion  412   a  of the plurality of fins  126  can be positioned at a lower portion of the body  402 ). The second portion  412   b  of the plurality of fins  126  can include fins  126  that are each positioned at a second angle  414   b  and are located between the first portion  412   a  and the third portion  412   c  (e.g., the second portion  412   b  of the plurality of fins  126  can be positioned at a center portion of the body  402 ). The third portion  412   c  of the plurality of fins  126  can include fins  126  that are each positioned at a third angle  414   c  and are located proximate the second end  406  of the body  402  (e.g., the third portion  412   c  of the plurality of fins  126  can be positioned at an upper portion of the body  402 ). The first portion  412   a , the second portion  412   b , and the third portion  412   c  can each include the same number of fins  126 . As illustrated in  FIG. 4B , each portion  412   a ,  412   b ,  412   c  of the plurality of fins  126  can include four fins  126 . Alternatively, the first portion  412   a , the second portion  412   b , and the third portion  412   c  can each include a different number of fins  126 . The first angle  414   a  can be smaller than the second angle  414   b , and the second angle  414   b  can be smaller than the third angle  414   c , such that the angle  414  can incrementally increase as the fins  126  extend along the length of the body  402  from the first end  404  to the second end  406 . The angle  414  can be any angle less than 90 degrees and greater than 0 degrees. Optionally, the angle  414  of the fin and/or fins  126  proximate the first end  404  can be between approximately 20 degrees and approximately 35 degrees, and the angle  414  of the fin and/or fins  126  proximate the second end  406  can be between approximately 50 degrees and approximately 65 degrees. As a nonlimiting example, the first angle  414   a  can be approximately 25 degrees, the second angle  414   b  can be between approximately 30 degrees with respect to the body  402 , and the third angle  414   c  can be approximately 60 degrees with respect to the body  402 . 
     Alternatively, the angle  414  at which each fin of the plurality of fins  126  is disposed can progressively increase as the plurality of fins  126  extend along the body  402  from the first end  404  to the second end  406 , such that each angle  414  is different. In such configuration, the fin  126  closest to the first end  404  can be positioned at the smallest angle, and the fin  126  closest to the second end  406  can be positioned at the largest angle, and the fins  126  positioned between such fins  126  can be disposed at a gradually increasing angle  414 . By way of example, the fin closest to the first end  404  can be positioned at an angle  414  of between approximately 25 degrees and approximately 35 degrees and the fin  126  closest to the second end  406  can be positioned at an angle  414  of between approximately 50 degrees and approximately 65 degrees. The fins  126  disposed between the fin closest the first end and the fin closest the second end can each be positioned at an angle  414  such that the angle  414  progressively increases as the fins extend from the first end  404  to the second end  406 . Optionally, the angle  414  at which each fin is disposed on the body  402  can progressively increase by between approximately 2 degrees and approximately 5 degrees as the fins  126  extend from the first end  404  to the second end  406 . 
     By progressively increasing and/or incrementally increasing the angle  414  at which the plurality of fins  126  are disposed on the body  402 , the baffle  124  can include a greater number of fins  126  as compared to baffles in the prior art, as the predetermined distance  416  between adjacent fins can be smaller than if each fin was positioned at the same angle. Additionally, by progressively increasing and/or incrementally increasing the angle  414  at which the plurality of fins  126  are disposed on the body  402 , excess restriction in the flow of the hot combustion gases can be minimized, thereby reducing the buildup of carbon dioxide and/or carbon monoxide. 
     As illustrated in  FIGS. 4A-4C , each fin  126  can have substantially the same cross-section area and cross-section shape. The cross-section area of each fin  126  and/or the angle  412  at which each fin  124  is bent can be sized relative to the inner diameter ID of the heat exchanger tube  122  such that there is a minimum sized gap between the outer edge of the fin  126  and the inner wall of the heat exchanger tube  122 . By way of example, the gap between the outer edge of the fin  126  and the inner wall of the heat exchanger tube  122  can be approximately ⅛ inch, ¼ inch, or ½ inch. The cross-section shape can be any shape. As illustrated in  FIG. 5A , each fin  126  can have a cross-section shape that is a substantially half-circle. Optionally, as illustrated in  FIG. 5B , each fin  126  can have a cross-section shape that is a substantially quarter-circle. Although  FIGS. 5A and 5B  illustrate example cross-section shapes of the fins  126 , it is contemplated that the cross-section shape can also be substantially rectangular, ovular, triangular, and/or polygonal. Optionally, the cross-section shape of the fins  126  can be irregular (e.g., the fin  126  can include a wavy, corrugated, and/or zig-zag configuration for at least one side). Optionally, as illustrated in  FIG. 5C , one or more of the fins  126  can include one or more apertures  502 . The one or more apertures  502  can be disposed at any location on the fin  126  and can serve to further disrupt the natural laminar flow of the hot combustion gases flowing through the heat exchanger tube  122 . 
     The baffle  124  can promote efficient heat transfer, and thereby, efficient heating of fluid within the tank  106 . The plurality of fins  126  can increase residence time of the hot combustion gases flowing through each heat exchanger tube  122  as compared to heat exchanger tubes without a baffle and/or heat exchanger tubes with baffles known in the prior art. Accordingly, the hot combustion gases can remain in the heat exchanger tube for a greater amount of time as compared to fluid heating devices and/or heat exchangers in the prior art, allowing for heat transfer to be improved. The angle  414  at which each fin of the plurality of fins  126  is disposed and the cross-section shape and cross-section area of each fin  126  can be selectively determined to control pressure drop within the hot combustion gases over the length of each heat exchanger tube  122  so that the increased residence time of the hot combustion gases within each heat exchanger tube  122  and the enhanced heat transfer is not at the disadvantage of impeded exhaust flow. Accordingly, heat loss, which commonly occurs in conventional fluid heating devices when in stand-by mode (e.g., when holding a contained amount of fluid in the tank at a predetermined set temperature) can be minimized. Additionally, the angle  414  at which each fin of the plurality of fins  126  is disposed and the cross-section shape and cross-section area of each fin  126  can be selectively determined to ensure the plurality of fins  126  do not impede the natural laminar flow of the hot combustion to an extent that the production of carbon monoxide and carbon dioxide emissions is undesirable. 
       FIG. 6  is a flow diagram outlining a method  600  of manufacturing an example baffle  124 . The method  600  can include providing  602  a sheet of metal (e.g., the body  402 ) having a first side  408   a  and a second side  408   b  and extending a length L from a first end  404  to a second end  406 . The sheet of metal can include stainless steel, carbon steel, aluminized steel, or any other suitable sheet metal adapted for puncturing, cutting, stamping, and/or bending. Optionally, the second end  406  of the sheet of metal can include a hanging end  410  that extends past the width of the sheet of metal. 
     The method  600  can include penetrating  604  the sheet of metal to form a plurality of fins  126  disposed on at least a portion of the length L of the sheet of metal. Any tool capable of puncturing, cutting, stamping, and/or the like can be used to penetrate the sheet of metal. By way of example, a laser cutting tool can be used to create a cut having a substantially arc shape. 
     The method  600  can include bending  606  each fin of the plurality of fins  126  at an angle  414  relative to the central axis A of the sheet of metal such that the fins  126  point generally upwards towards the second end  406  of the sheet of metal. A first fin can be bent outwards from the first side  408   a  of the sheet of metal and an adjacent fin can be bent outwards from the second side  408   b  of the sheet of metal. In such configuration, the plurality of fins can be bent outwards in an alternating manner. The fin proximate to the first end  404  of the sheet of metal can be bent outwards at a first angle and the fin proximate to the second end  406  of the sheet of metal can be bent outwards at a second angle. The first angle can be less than the second angle. By way of example, the first angle can be between approximately 20 degrees and 35 degrees and the second angle can be between approximately 50 degrees and approximately 65 degrees. The fins disposed between the fin proximate to the first end  404  and the fin proximate to the second end  406  can be bent at an angle  414  that progressively and/or incrementally increases as the plurality of fins  126  extend along the length of the sheet of metal from the first end  404  to the second end  406 . 
     By manufacturing the baffle  124  using a single sheet of metal, welding of the fins  126  and/or other components of the baffle can be avoided, and thus, the costs associated therewith can also be avoided. This can allow the manufacturing of the baffle  124  to be relatively easy and cost-effective as compared to other known baffles in the prior art. The cost of manufacturing the baffle  124  can be approximately 50% lower as compared to the cost of manufacturing other known baffles known in the prior art. Additionally, the weight of the baffle  124  can be minimized due to creating the fins by penetrating (e.g., puncturing, stamping, laser cutting, and the like) the sheet of the metal. 
     Certain examples and implementations of the disclosed technology are described above with reference to block and flow diagrams according to examples of the disclosed technology. It will be understood that one or more blocks of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and flow diagrams, respectively, can be implemented by computer-executable program instructions. Likewise, some blocks of the block diagrams and flow diagrams do not necessarily need to be performed in the order presented, can be repeated, or do not necessarily need to be performed at all, according to some examples or implementations of the disclosed technology. It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Additionally, method steps from one process flow diagram or block diagram can be combined with method steps from another process diagram or block diagram. These combinations and/or modifications are contemplated herein.