Patent Publication Number: US-2017356697-A1

Title: Fin element for a heat exchanger

Description:
This nonprovisional application claims priority under 35 U.S.C. §119(a) to German Patent Application No. 10 2016 210 159.5, which was filed in Germany on Jun. 8, 2016, and which is herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a fin element for a heat exchanger, and a heat exchanger formed with a fin element of this kind. 
     Description of the Background Art 
     DE 10 2009 021 179 A1 discloses a fin element for a heat exchanger, comprising a ribbed plate corrugated in a longitudinal direction and disposed between two structures, whereby a gaseous fluid can flow through the ribbed plate in a depth direction to transfer heat between the structures and the fluid and whereby a plurality of gills, arranged parallel one behind the other and extending transverse to the depth direction, with a gill depth and a gill angle relative to the depth direction are provided in the ribbed plate, whereby the gill angle is between 14° and 26°, whereby the gill depth is either in the range of 0.3 mm to 0.6 mm or in the range of 1.1 mm to 1.8 mm. 
     DE 10 2013 108 357 A1 discloses a lamellar element, having lamellae that are integrally connected to one another via connecting sections. To increase stiffness, the lamellar element is acted upon by its connecting sections approximately in the direction of the lamellae with a pressing force during manufacture, whereby at least the connecting sections are plastically deformed. In addition or alternatively, corrugations are introduced in some or all lamellae. 
     EP 2 125 404 B1 discloses an airflow heating device for a heating or air conditioning system of a vehicle, comprising a heating element, which is disposed in an airflow region and comprises an electrically conductive nonwoven fabric. EP 2 125 404 B1 discloses in addition an auxiliary heating device and a vehicle heating or air conditioning system, which comprises the airflow heating device. 
     EP 2 049 860 B1 discloses a corrugated fin with corrugation peaks or corrugation valleys and adjoining perpendicular or slightly inclined corrugation flanks having a bent edge, the corrugation flanks being arranged in each case between two flat tubes in a heat exchanger, whereby the corrugation flanks are provided with incisions formed out of their planes, whereby the bent edges are formed weakened such that the springback occurring during bending is reduced. 
     DE 10 2012 109 768 A1 discloses a radiator element for an air heater, a heating stage of an air heater of this kind, and a method for manufacturing a radiator element, in which a corrugated fin element is electrically contacted directly by screwing in of a contact element. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a fin element for a heat exchanger, which enables good heat transfer at a low pressure drop and a simultaneously high stability. In addition, it is the object of the invention to provide a heat exchanger, which is improved with respect to good heat transfer at a low pressure drop and a simultaneously high stability. 
     An exemplary embodiment of the invention relates to a fin element for a heat exchanger, in particular for a heating, ventilation, and/or air conditioning system of a motor vehicle, with a plurality of connecting sections and longitudinal sections, whereby in each case two adjacent longitudinal sections are connected to one another by a connecting section, whereby at least one of the longitudinal sections has gills formed by webs and slots, whereby at least one of the webs has a flared web surface, whereby the web surface is flared out from the at least one longitudinal section, characterized in that the web surface forms at least two surface sections arranged angled to one another. Such a manner of execution enables an especially good heat transfer and in addition represents an exceptionally stable design form. The indicated design moreover combines in an optimal manner the necessary stability with as low a pressure loss as possible when the airflow to be heated flows through the heat exchanger. The gills in this case allow the distribution of partial airflows transverse to the flow direction of a main airflow and improve the heat transfer. 
     In an embodiment, a plurality of the webs or each web has a web surface which is flared out from the at least one longitudinal section and forms at least two surface sections arranged angled to one another. 
     Moreover, for example, a plurality or all of the longitudinal sections have flared web surfaces with at least two surface sections arranged angled to one another. 
     Advantageously, flow chambers are formed between the connecting sections and the longitudinal sections; said chambers can be flown through in a depth direction T in particular by air, whereby the surface sections, formed by the particular web surfaces, intersect the depth direction T at an angle β. The stability of the fin element is improved still further by this construction. 
     In addition, the webs may have a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile and/or web sections with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile, whereby the webs with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile and/or the web sections with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile are flared out from a first side of the at least one connecting section and/or from a second side, opposite to the first side, of the at least one connecting section. As a result, the stability of the fin element is increased, in particular in the area of the gills. Moreover, the heat transfer and also the velocity profile of the air flowing through the gills are optimized. 
     Moreover, a number of webs, arranged adjacent to one another, can form at least one group, whereby the at least one group has an arrangement pattern, specific for the at least one group, comprising a series of webs each with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile and/or web sections each with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile. 
     A further manner of execution provides that the at least one connecting section has a plurality of groups, each of which has an arrangement pattern, specific for the particular group, comprising a series of webs each with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile and/or web sections each with a V-shaped, W-shaped, Z-shaped, hook-shaped, and/or I-shaped cross-sectional profile. The heat exchange surfaces and also the connecting surfaces, available for connection to heat transfer elements, can be adapted to the particular requirement by means of these modes of execution. 
     In addition, the at least one connecting section can have at least one web surface group that repeats periodically along the at least one connecting section. 
     An embodiment provides that the at least one group of web surfaces has at least one mirror axis, arranged transverse to the depth direction T and substantially parallel to the web surfaces, such that the at least one group of web surfaces has at least two web surface sections made mirror-symmetric to one another. As a result, a high efficiency is achieved for a heat exchange network composed of heat transfer elements and fin elements. 
     An embodiment provides that the longitudinal sections and the connecting sections form a U-shaped, V-shaped, rectangular, trapezoidal, and/or Ω-shaped cross-sectional profile. 
     Moreover, the connecting sections can be connected materially, frictionally, and/or positively locking to heat exchange surfaces of the heat exchanger in such a way that the fin elements increase the heat transfer surfaces of the heat exchanger. This leads to an optimal heat conduction between the heat transfer elements and the fins of the fin element. 
     An exemplary embodiment of the heat exchanger provides that the heat exchanger has at least one fin element for a heat exchanger according to the description given above. 
     The heat exchanger can have at least two heat transfer elements, whereby a fin element formed according to the description given above is disposed between the two heat transfer elements. 
     The heat exchanger can be, for example, an electrical heating device. The use of the fin element of the invention is especially effective in such a device. 
     The electrical heating device advantageously has PTC heating elements, whereby the fin elements and the PTC heating elements are arranged adjacent to one another. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG. 1  shows a perspective view of a fin element of the invention; 
         FIG. 2  shows a sectional view of a detail of a fin element according to  FIG. 1 ; 
         FIG. 3  shows a perspective view of an exemplary embodiment of a fin element; 
         FIG. 4  shows a sectional view of a detail of a fin element according to  FIG. 3 ; 
         FIG. 5  shows a perspective view of an exemplary embodiment of a fin element; 
         FIG. 6  shows a sectional view of a detail of a fin element according to  FIG. 5 ; 
         FIG. 7  shows a perspective view of a detail of a fin element according to  FIGS. 1 and 2 ; 
         FIG. 8  shows a perspective view of a detail of a fin element according to  FIGS. 3 and 4 ; 
         FIG. 9  shows a perspective view of a detail of a fin element according to  FIGS. 5 and 6 ; 
         FIG. 10  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 11  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 12  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 13  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 14  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 15  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 16  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 17  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 18  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 19  shows a sectional view of an embodiment of a detail of a fin element according to  FIGS. 1 to 6 ; 
         FIG. 20  shows a sectional view of a detail of a fin element according to  FIGS. 5, 6, and 9 ; and 
         FIG. 21  shows an illustration of the distribution of the air velocity in a detail of a fin element of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an exemplary embodiment of a fin element  1  of the invention for a heat exchanger, which is not shown in greater detail. In this regard,  FIG. 1  shows a representative detail of fin element  1 , which can extend in any length in longitudinal direction L, depending on the particular requirements. 
     The heat exchanger can be, for example, a heating element for a motor vehicle. It can also be a coolant cooler or some other heat exchanger. Fin elements  1  in this case are disposed between heat transfer elements, which are not shown in  FIG. 1  and which may be, for example, electrical heating elements or also tubes through which a heated coolant flows. Together with these heat transfer elements, a plurality of fin elements  1  form a heat exchanger block, which is normally used for heating an airflow. In this case, the airflow flows through the heat exchanger block in a depth direction T, which runs in the direction of a depth of the heat exchanger perpendicular to longitudinal direction L. The heat transfer elements, whose heat transfer surfaces are increased by means of fin elements  1 , heat the airflow. This can then be used in particular for the energy-efficient heating of a vehicle cabin. 
     Fin element  1  in the exemplary embodiment shown in  FIG. 1  is made as a corrugated fin with fins  2  and gills  3  of a continuous sheet corrugated in longitudinal direction L. Fins  2  and gills  3  in this case are made as one piece by a stamping, rolling, and/or folding method. In this case, fins  2  of fin element  1  have longitudinal sections  4  on which gills  3  are disposed. Longitudinal sections  4  of fins  2  of fin element  1  can have in each case a plurality of gills  3 . Alternatively, some of longitudinal sections  4  can have no gills  3 . 
     Fins  2  are arranged in rows in longitudinal direction L of fin element  1 . In this case, fin element  1  has a first long side  5  and a second long side  6 , opposite to first long side  5 . Longitudinal sections  4  run from first long side  5  to second long side  6  or from second long side  6  to first long side  5 . In the area of long sides  5 ,  6  of fin element  1 , fins  2  have connecting sections  7 , which connect together the two longitudinal sections  4  of a fin  2  and, moreover, form connecting surfaces for connecting fin element  1  to the heat transfer elements. Heat can be transferred via the connecting surfaces, formed by connecting sections  7 , from heat transfer elements to fins  2  of fin element  1  and from there to the airflow. 
     Between their longitudinal sections  4  and connecting sections  7 , fins  2  form flow chambers  8  through which the airflow flows, in particular in depth direction T. Moreover, partial airflows of the airflow flow through gills  3  out of flow chambers  8  into the particular adjacent flow chambers  8 . The result is that, apart from the flow through flow chambers  8  in depth direction T, there is also a flow through flow chambers  8 , said flow being substantially transverse to depth direction T. Flow chambers  8  in the exemplary embodiment shown in  FIG. 1  are also bounded by connecting sections  7 , apart from longitudinal sections  4 . In this case, flow chambers  8 , cut along longitudinal direction L of fin element  1 , have a longitudinally extended cross-sectional profile, whereby connecting sections  7  are each formed U-shaped. 
     End longitudinal sections  4  of end fins  2  of fin element  1 , which are not shown in  FIG. 1 , are connected in each case to another longitudinal section  4  via one of connecting sections  7  in the area of first long side  5  or second long side  6 . The other longitudinal sections  4 , not located at the ends, are connected via connecting sections  7  in each case to two other longitudinal sections  4  in the area of first long side  5  or second long side  6 . 
       FIG. 2  shows a sectional view of fin element  1  shown in  FIG. 1 , whereby the cut is made in longitudinal direction L of fin element  1 . Fin element  1  in longitudinal direction L of fin element  1  has fins  2  arranged in rows, whereby an airflow can flow through flow chambers  8 , formed between longitudinal sections  4  and connecting sections  7 , in depth direction T of fin element  1 , said direction being perpendicular to longitudinal direction L. 
     Fin element  1  has a first long side  5  and a second long side  6  opposite to first long side  5 . Longitudinal sections  4  of fins  2  are arranged running from first long side  5  to second long side  6  or from second long side  6  to first long side  5 . Connecting sections  7  each connect two adjacent longitudinal sections  4  and are each disposed in the area of first long side  5  or second long side  6 . Connecting sections  7  can be connected frictionally, positively locking, and/or materially to the heat transfer elements. Preferably gluing or soldering methods are used for this purpose. In the exemplary embodiment shown in  FIG. 2 , connecting sections  7  are formed curved in a U-shape such that they are concavely curved toward flow chambers  8  and convexly curved toward the heat transfer elements. 
     Longitudinal sections  4  have gills  3  which are arranged in rows along longitudinal sections  4 . Exemplary embodiments of gills  3  will be described in greater detail in  FIGS. 7 to 9 . 
       FIG. 3  shows a further exemplary embodiment of fin element  101  of the invention for a heat exchanger. which is not shown in greater detail. In this regard,  FIG. 3  shows a representative detail of fin element  101 , which can extend in any length in longitudinal direction L, depending on the particular requirements. 
     The heat exchanger can be, for example, a heating element for a motor vehicle. Fin elements  101  in this case are disposed between the heat transfer elements, which are not shown in  FIG. 3  and which may be, for example, electrical heating elements or also tubes through which a heated coolant flows. Together with these heat transfer elements, a plurality of fin elements  101  form a heat exchanger block, which is normally used for heating an airflow. In this case, the airflow flows through the heat exchanger block in a depth direction T, which runs in the direction of a depth of the heat exchanger block perpendicular to longitudinal direction L. The heat transfer elements, whose heat transfer surfaces are increased by means of fin elements  101 , heat the airflow. This can then be used in particular for the energy-efficient heating of a vehicle cabin. 
     Fin element  101  in the exemplary embodiment shown in  FIG. 3  is made as a corrugated fin with fins  102  and gills  103  of a continuous sheet corrugated in longitudinal direction L. Fins  102  and gills  103  in this case are made as one piece by a stamping, rolling, and/or folding method. In this case, fins  102  of fin element  101  have longitudinal sections  104  on which gills  103  are disposed. Longitudinal sections  104  of fins  102  can have in each case a plurality of gills  103 . Alternatively, some of longitudinal sections  104  can also have no gills  103 . 
     Fins  102  are arranged in rows in longitudinal direction L of fin element  101 . In this case, fin element  102  has a first long side  105  and a second long side  106 , opposite to first long side  105 . Longitudinal sections  104  run from first long side  105  to second long side  106  or from second long side  106  to first long side  105 . In the area of long sides  105 ,  106 , fins  102  of fin element  101  have connecting sections  107 , which in each case connect together the two longitudinal sections  104  of a fin  102  and, moreover, form connecting surfaces for connecting fins  102  of fin element  101  to the heat transfer elements. Heat can be transferred via the connecting surfaces, formed by connecting sections  107 , from heat transfer elements to longitudinal sections  104  of fins  102  and from these to the airflow. Connecting sections  107  in the exemplary embodiment shown in  FIG. 3  are arranged substantially perpendicular to longitudinal sections  104 . 
     Between their longitudinal sections  104  and connecting sections  107 , fins  102  of fin element  101  form flow chambers  108  through which the airflow can flow, in particular in depth direction T. Moreover, partial airflows of the airflow flow through gills  103  out of flow chambers  108  into the particular adjacent flow chambers  108 . The result is that, apart from the flow through flow chambers  108  in depth direction T, there is also a flow by the partial airflows through flow chambers  108 , said flow being substantially transverse to depth direction T. Flow chambers  108  in the exemplary embodiment shown in  FIG. 3  are also bounded by connecting sections  107 , apart from longitudinal sections  104 . In this regard, flow chambers  108 , cut along longitudinal direction L of fin element  101 , have a longitudinally extended rectangular cross-sectional profile. 
       FIG. 4  shows a sectional view of fin element  101  shown in  FIG. 3 , whereby the cut is made in longitudinal direction L of fin element  101 . Fin element  101  in longitudinal direction L of fin element  101  has fins  102  arranged in rows, whereby an airflow can flow through flow chambers  108 , formed between longitudinal sections  104  and connecting sections  107  of fins  102  of fin element  101 , in depth direction T of fin element  101 , said direction being perpendicular to longitudinal direction L. 
     Fin element  101  has a first long side  105  and a second long side  106  opposite to first long side  105 . Longitudinal sections  104  of fins  102  are arranged running from first long side  105  to second long side  106  or from second long side  106  to first long side  105 . Connecting sections  107  each connect two adjacent longitudinal sections  104  and are each disposed in the area of first long side  105  or second long side  106 . Connecting sections  107  can be connected frictionally, positively locking, and/or materially to the heat transfer elements. Preferably gluing or soldering methods are used for this purpose. In the exemplary embodiment shown in  FIG. 4 , connecting sections  107  are arranged perpendicular to longitudinal sections  104  in such a way that they form a relatively large connecting surface for connecting fin element  101  to the heat transfer elements. Longitudinal sections  104  have gills  103  which are arranged in rows along longitudinal sections  104 . Exemplary embodiments of gills  103  will be described in greater detail in  FIGS. 7 to 9 . 
       FIG. 5  shows a further exemplary embodiment of fin element  201  of the invention for a heat exchanger, which is not shown in greater detail. In this regard,  FIG. 5  shows a representative detail of fin element  201 , which can extend in any length in longitudinal direction L, depending on the particular requirements. 
     The heat exchanger can be, for example, a heating element for a motor vehicle. Fin elements  201  in this case are disposed between the heat transfer elements, which are not shown in  FIG. 5  and which may be, for example, electrical heating elements or also tubes through which a heated coolant flows. Together with these heat transfer elements, a plurality of fin elements  201  form a heat exchanger block, which is normally used for heating an airflow. In this case, the airflow flows through the heat exchanger block in a depth direction T, which runs in the direction of a depth of the heat exchanger perpendicular to longitudinal direction L. The heat transfer elements, whose heat transfer surfaces are increased by means of fin elements  201 , heat the airflow. This can then be used in particular for the energy-efficient heating of a vehicle cabin. 
     Fin element  201  in the exemplary embodiment shown in  FIG. 5  is made as a corrugated fin with fins  202  and gills  203  of a continuous sheet corrugated in longitudinal direction L. Fins  202  and gills  203  in this case are made as one piece by a stamping, rolling, and/or folding method. In this case, fins  202  of fin element  201  have longitudinal sections  204  on which gills  203  are disposed. Longitudinal sections  204  of fins  202  can have in each case a plurality of gills  203 . Alternatively, some of longitudinal sections  204  can also have no gills  203 . 
     Fins  202  are arranged in rows in longitudinal direction L of fin element  201 . In this case, fin element  201  has a first long side  205  and a second long side  206 , opposite to first long side  205 . Longitudinal sections  204  of fins  202  run disposed obliquely from first long side  205  to second long side  206  or from second long side  206  to first long side  205 . In this case, each two longitudinal sections  204  form the two legs of a V shape. In the area of long sides  205 ,  206 , fins  202  of fin element  201  have connecting sections  207 , which form connecting surfaces for connecting fin element  201  to the heat transfer elements. Heat can be transferred via the connecting surfaces, formed by connecting sections  207 , from heat transfer elements to longitudinal sections  204  of fins  202  of fin element  201  and from these to the airflow. 
     Between their longitudinal sections  204  and their connecting sections  207 , fins  202  form flow chambers  208  through which the airflow flows, in particular in depth direction T. Moreover, partial airflows of the airflow flow through gills  203  out of flow chambers  208  into the particular adjacent flow chambers  208 . The result is that, apart from the flow through flow chambers  208  in depth direction T, there is also a flow by the partial airflows through flow chambers  208 , said flow being substantially transverse to depth direction T. Flow chambers  208  in the exemplary embodiment shown in  FIG. 5  are also bounded by connecting sections  207 , apart from longitudinal sections  204 . In this regard, flow chambers  208 , cut along longitudinal direction L of fin element  201 , have a longitudinally extended V-shaped cross-sectional profile. 
       FIG. 6  shows a sectional view of fin element  5  shown in  FIG. 201 , whereby the cut is made in longitudinal direction L of fin element  201 . Fin element  201  in longitudinal direction L of fin element  201  has fins  202  arranged in rows, whereby an airflow can flow through these from longitudinal sections  204  and connecting sections  207  of fins  202  of fin element  201  in depth direction T, disposed perpendicular to longitudinal direction L of fin element  201 . 
     Fin element  201  has a first long side  205  and a second long side  206  opposite to first long side  205 . Longitudinal sections  204  of fins  202  of fin element  201  are arranged running obliquely from first long side  205  to second long side  206  or from second long side  206  to first long side  205 . Connecting sections  207  each connect two adjacent longitudinal sections  204  and are each disposed in the area of first long side  205  or second long side  206 . Connecting sections  207  can be connected frictionally, positively locking, and/or materially to the heat transfer elements. Preferably gluing or soldering methods are used for this purpose. In the exemplary embodiment shown in  FIG. 6 , connecting sections  207  are arranged angled to longitudinal sections  204 . 
     Longitudinal sections  204  of fins  202  have gills  203  which are arranged in rows along longitudinal sections  204 . Exemplary embodiments of gills  203  will be described in greater detail in  FIGS. 7 to 9 . 
       FIG. 7  shows a detail of a fin element  1  formed according to  FIGS. 1 and 2 . Gills  3  are formed at longitudinal sections  4  of fins  2 , said sections being arranged running between the two long sides  5 ,  6  of fin element  1 . Longitudinal sections  4  each form a first plane whereby webs  9  flare out from said plane. A slot  10 , which is formed by an opening in the material forming longitudinal sections  4  of fins  2 , is disposed in each case between two webs  9 . Webs  9  and slots  10  together form gills  3 . 
     Webs  9  have web surfaces  11  flaring out from longitudinal sections  4 . Web surfaces  11  each have two surface sections  12 ,  13 , a first surface section  12  and a second surface section  13 . The two surface sections  12 ,  13  are arranged angled to one another. Here, the two surface sections  12 ,  13  each form a leg  14 ,  15  of an angle α. In this regard, the angle α in the exemplary embodiment shown in  FIG. 7  is about 160° in size. In alternative exemplary embodiments, the angle α can also be greater or smaller. 
     Surface sections  12 ,  13  in each case intersect depth direction T, in which an airflow to be heated flows through flow chambers  8 , formed by longitudinal sections  4  and connecting sections  7  of fins  2  of fin element  1 , at an angle β. The angle β in the exemplary embodiments shown in  FIGS. 7 to 9  is smaller than 90°. 
       FIG. 8  shows a detail of a fin element  101  formed according to  FIGS. 3 and 4 . Gills  103  are formed at longitudinal sections  104  of fins  102  of fin element  101 , said sections being arranged running between the two long sides  105 ,  106  of fin element  101 . Webs  109  are flared out from longitudinal sections  104 . A slot  110 , which is formed by an opening in the material forming longitudinal sections  104  of fins  102  of fin element  101 , is disposed in each case between two webs  109 . Webs  109  and slots  110  together form gills  103 . 
     Webs  109  have web surfaces  111  flaring out from longitudinal sections  104 . Web surfaces  111  each have two surface sections  112 ,  113 , a first surface section  112  and a second surface section  113 . The two surface sections  112 ,  113  are arranged angled to one another. Here, the two surface sections  112 ,  113  each form a leg  114 ,  115  of an angle α. In this regard, the angle α in the exemplary embodiment shown in  FIG. 8  is about 160° in size. In alternative exemplary embodiments, the angle α can also be greater or smaller. 
     Surface sections  112 ,  113  intersect depth direction T, in which an airflow to be heated flows through flow chambers  108 , formed by longitudinal sections  104  and connecting sections  107  of fins  102  of fin element  101 , at an angle β. The angle β in the exemplary embodiments shown in  FIGS. 7 to 9  is smaller than 90°. 
       FIG. 9  shows a detail of a fin element  201  formed according to  FIGS. 5 and 6 . Gills  203  are formed at longitudinal sections  204  of fins  202 , said sections being arranged running between the two long sides  205 ,  206  of fin element  201 . Webs  209  are flared out from longitudinal sections  204 . A slot  210 , which is formed by an opening in the material forming longitudinal sections  204  of fins  202  of fin element  101 , is disposed in each case between two webs  209 . Webs  209  and slots  210  together form gills  203 . 
     Webs  209  have web surfaces  211  flaring out from longitudinal sections  204 . Web surfaces  211  each have two surface sections  212 ,  213 , a first surface section  212  and a second surface section  213 . The two surface sections  212 ,  213  are arranged angled to one another. Here, the two surface sections  212 ,  213  each form a leg  214 ,  215  of an angle α. The angle α in the exemplary embodiment shown in  FIG. 9  is about 110° in size. In alternative exemplary embodiments, the angle α can also be greater or smaller. 
     Surface sections  212 ,  213  intersect depth direction T, in which an airflow to be heated flows through flow chambers  208 , formed by longitudinal sections  204  and connecting sections  207  of fins  202  of fin element  101 , at an angle β. The angle β in the exemplary embodiments shown in  FIGS. 7 to 9  is smaller than 90°. 
       FIGS. 10 to 19  show exemplary embodiments of gills with alternative cross-sectional shapes of the webs shown in  FIGS. 7 to 9 . The direction of the cut corresponds hereby to the depth direction T shown in  FIGS. 7 to 9 . In this case, the webs each have by way of example a substantially V-shaped cross-sectional profile  16 , a substantially W-shaped cross-sectional profile  17 , a substantially hook-shaped cross-sectional profile  18 , a substantially Z-shaped cross-sectional profile  19 , or a substantially I-shaped cross-sectional profile  20 . Moreover, the webs can also have web sections with substantially V-shaped, substantially W-shaped, substantially hook-shaped, substantially Z-shaped, and/or substantially I-shaped cross-sectional profiles. 
     In this case, in the exemplary embodiments shown in  FIGS. 10 to 19 , a number of webs formed adjacent to one another on a longitudinal section of a fin of a fin element of the invention form a group. The particular group  22  has a specific arrangement pattern of a series of webs, each with a substantially V-shaped cross-sectional profile  16 , a substantially W-shaped cross-sectional profile  17 , a substantially hook-shaped cross-sectional profile  18 , a substantially Z-shaped cross-sectional profile  19 , and/or a substantially I-shaped cross-sectional profile  20 . 
     A group in this case can extend over the entire length of the long side of a fin of a fin element of the invention. Alternatively, a plurality of identical and/or different groups can also be arranged along a long side of a fin of the fin element. 
     The groups specifically formed in this way can repeat periodically along a longitudinal section. Moreover, a plurality of differently formed groups can be arranged along a longitudinal section. 
       FIG. 10  shows a first exemplary embodiment of a group  26  of webs arranged on a longitudinal section  21  of a fin of a fin element of the invention. Group  26  has a mirror axis  51 , which divides group  26  into two sections  27 ,  28 , formed mirror-symmetric to one another and adjacent to one another at mirror axis  51 . A web with a substantially V-shaped cross-sectional profile  16  is disposed at mirror axis  51 . The two legs of the V-shaped cross-sectional profile form an angle whose vertex is located on mirror axis S 1 . Peak  29  of V-shaped cross-sectional profile  16  in this case is flared out from a first side  30  of longitudinal section  21 . 
     The two sections  27 ,  28  each have a web with a substantially Z-shaped cross-sectional profile  19 , each with a first peak  31  and a second peak  32 . First peaks  31  are each flared out from first side  30  of longitudinal section  21 . Second peaks  32  are each flared out from a second side  33 , opposite to first side  30 , of longitudinal section  21 . 
       FIG. 11  shows a further exemplary embodiment of a group  126  of webs arranged on a longitudinal section  121  of a fin of a fin element of the invention. Group  126  has a mirror axis S 2 , which divides group  126  into two sections  127 ,  128 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 2 . A web with a substantially W-shaped cross-sectional profile  17  is disposed at mirror axis S 2 . The two hook-shaped sides of the W-shaped cross-sectional profile  17  form an angle whose vertex is located on mirror axis S 2 . Peaks  129  of the two hook-shaped sides of the W-shaped cross-sectional profile  17  are flared out from a first side  130  of longitudinal section  121 . 
     The two sections  127 ,  128  each have a web with an I-shaped cross-sectional profile  20  and a web with a substantially hook-shaped cross-sectional profile  18 , each of which are made flared out in sections from first side  130  of longitudinal section  121  and from a second side  133 , opposite to first side  130 , of longitudinal section  121 . 
       FIG. 12  shows a further exemplary embodiment of a group  226  of webs arranged on a longitudinal section  221  of a fin of a fin element of the invention. Group  226  has a mirror axis S 3 , which divides group  226  into two sections  227 ,  228 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 3 . 
     A web with a substantially W-shaped cross-sectional profile  17  is disposed at mirror axis S 3 . The two hook-shaped sides of the W-shaped cross-sectional profile  17  form an angle whose vertex is located on mirror axis S 3 . Peaks  229  of the two hook-shaped sides of the W-shaped cross-sectional profile  17  are flared out from a first side  230  of longitudinal section  221 . 
     The two sections  227 ,  228  each have a web with an I-shaped cross-sectional profile  20  and a web with a substantially hook-shaped cross-sectional profile  18 , each of which are made flared out in sections from first side  230  of longitudinal section  221  and from a second side  233 , opposite to first side  230 , of longitudinal section  121 . 
     Group  226  has a first outer edge  234  and a second outer edge  235 . The webs with the substantially hook-shaped cross-sectional profile  18  are each disposed at one of the two outer edges  234 ,  235  of group  226 . The web, disposed at first outer edge  234 , with a substantially hook-shaped cross-sectional profile  18  has a web end  236 , facing first outer edge  234  and placed substantially parallel to depth direction T. The web, disposed at second outer edge  235 , with a substantially hook-shaped cross-sectional profile  18  has a web end  237 , facing second outer edge  235  and placed substantially parallel to depth direction T. 
     Apart from this feature, the exemplary embodiments shown in  FIGS. 11 and 12  differ with respect to the size of the angle with which the webs with an I-shaped cross-sectional profile  20  intersect depth direction T. 
       FIG. 13  shows a further exemplary embodiment of a group  326  of webs arranged on a longitudinal section  321  of a fin of a fin element of the invention. Group  326  has a mirror axis S 4 , which divides group  326  into two sections  327 ,  328 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 4 . 
     A web with a substantially W-shaped cross-sectional profile  17  is disposed at mirror axis S 4 . The two hook-shaped sides of the W-shaped cross-sectional profile  17  form an angle whose vertex is located on mirror axis S 4 . Peaks  329  of the two hook-shaped sides of the W-shaped cross-sectional profile  17  are flared out from a first side  330  of longitudinal section  321 . 
     The two sections  327 ,  328  each have a web with an I-shaped cross-sectional profile  20  and a web with a substantially hook-shaped cross-sectional profile  18 , each of which are made flared out in sections from first side  330  of longitudinal section  121  and from a second side  333 , opposite to first side  330 , of longitudinal section  321 . 
     Group  326  has a first outer edge  334  and a second outer edge  335 . The webs with the substantially hook-shaped cross-sectional profile  18  are each disposed at one of the two outer edges  334 ,  335  of group  326 . The web, disposed at first outer edge  334 , with a substantially hook-shaped cross-sectional profile  18  has a web end  336 , facing first outer edge  334  and placed substantially parallel to depth direction T. The web, disposed at second outer edge  335 , with a substantially hook-shaped cross-sectional profile  18  has a web end  337 , facing second outer edge  335  and placed substantially parallel to depth direction T. 
     The exemplary embodiments shown in  FIGS. 11, 12, and 13  differ in particular with respect to the size of the angle, with which the webs with an I-shaped cross-sectional profile  20  intersect depth direction T. 
       FIG. 14  shows a further exemplary embodiment of a group  426  of webs arranged on a longitudinal section  421  of a fin of a fin element of the invention. Group  426  has a mirror axis S 5 , which divides group  426  into two sections  427 ,  428 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 5 . 
     A web with a substantially V-shaped cross-sectional profile  16  is disposed at mirror axis S 5 . The two legs of the V-shaped cross-sectional profile  16  form an angle whose vertex is located on mirror axis S 5 . In this case, both legs of the V-shaped cross-sectional profile  16  are flared out from a first side  430  of longitudinal section  421 . 
     The two sections  427 ,  428  each have three webs with a substantially hook-shaped cross-sectional profile  18 . The webs with the hook-shaped cross-sectional profile  18  are each flared alternately out from first side  430  of longitudinal section  421  or from a second side  433 , opposite to first side  430 , of longitudinal section  421 . 
     Group  426 , moreover, has a first outer edge  434  and a second outer edge  435 . A web with a substantially I-shaped cross-sectional profile  20  is disposed at outer edges  434 ,  435 . 
     The web, disposed at first outer edge  434 , with a substantially I-shaped cross-sectional profile  20  has a web end  436 , facing first outer edge  434  and placed substantially parallel to depth direction T. The web, disposed at second outer edge  435 , with a substantially I-shaped cross-sectional profile  20  has a web end  437 , facing second outer edge  435  and placed substantially parallel to depth direction T. 
       FIG. 15  shows a further exemplary embodiment of a group  526  of webs arranged on a longitudinal section  521  of a fin of a fin element of the invention. Longitudinal section  521  has a first side  530  and a second side  533  opposite to first side  530 . Group  526  has a mirror axis S 6 , which divides group  526  into two sections  527 ,  528 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 6 . 
     A web with a substantially V-shaped cross-sectional profile  16  is disposed at mirror axis S 6 . The two legs of the V-shaped cross-sectional profile  16  form an angle whose vertex is located on mirror axis S 6 . In this case, both legs of the V-shaped cross-sectional profile  16  are flared out from a second side  533  of longitudinal section  521 . 
     The two sections  527 ,  528  each have two further webs with a substantially V-shaped cross-sectional profile  16 . The webs with the substantially V-shaped cross-sectional profile  16  are each flared out alternately from first side  530  of longitudinal section  521  or from second side  533  of longitudinal section  521 . 
     Group  526 , moreover, has a first outer edge  534  and a second outer edge  535 . A web with a substantially I-shaped cross-sectional profile  20  is disposed at outer edges  534 ,  535 . 
     The web, disposed at first outer edge  534 , with a substantially I-shaped cross-sectional profile  20  has a web end  536 , facing first outer edge  534  and placed substantially parallel to depth direction T. The web, disposed at second outer edge  535 , with a substantially I-shaped cross-sectional profile  20  has a web end  537 , facing second outer edge  535  and placed substantially parallel to depth direction T. 
       FIG. 16  shows a further exemplary embodiment of a group  626  of webs arranged on a longitudinal section  621  of a fin of a fin element of the invention. Longitudinal section  621  has a first side  630  and a second side  633  opposite to first side  630 . Group  626  has a mirror axis S 7 , which divides group  626  into two sections  627 ,  628 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 7 . 
     A web with a substantially V-shaped cross-sectional profile  16  is disposed at mirror axis S 7 . The two legs of the V-shaped cross-sectional profile  16  form an angle whose vertex is located on mirror axis S 7 . In this case, both legs of the V-shaped cross-sectional profile  16  are flared out from a second side  633  of longitudinal section  621 . 
     The two sections  627 ,  628  each have three further webs with a substantially V-shaped cross-sectional profile  16 . The webs with the substantially V-shaped cross-sectional profile  16  are each flared out alternately from first side  630  of longitudinal section  621  or from second side  633  of longitudinal section  621 . 
     Group  626 , moreover, has a first outer edge  634  and a second outer edge  635 . A web with a substantially hook-shaped cross-sectional profile  18  is disposed at outer edges  634 ,  635 . In this case, the two webs with a substantially hook-shaped cross-sectional profile  18  are flared out from second side  633  of longitudinal section  621 . 
     The web, disposed on first outer edge  634 , with a substantially hook-shaped cross-sectional profile  18  has a first leg  638 , facing mirror axis S 7 , and a second leg  639 , facing first outer edge  634 , whereby second leg  639  is placed substantially parallel to depth direction T. 
     The web disposed in the area of second outer edge  635  and with a substantially hook-shaped cross-sectional profile  18  has a first leg  640 , facing mirror axis S 7 , and a second leg  641 , facing second outer edge  635 , whereby second leg  641  is placed substantially parallel to depth direction T. 
       FIG. 17  shows a further exemplary embodiment of a group  726  of webs arranged on a longitudinal section  721  of a fin of a fin element of the invention. Longitudinal section  721  has a first side  730  and a second side  733  opposite to first side  730 . Group  726  has a mirror axis S 8 , which divides group  726  into two sections  727 ,  728 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 8 . 
     A web with a substantially V-shaped cross-sectional profile  16  is disposed at mirror axis S 8 . The two legs of the V-shaped cross-sectional profile  16  form an angle whose vertex is located on mirror axis S 8 . In this case, a first section  742  of the V-shaped cross-sectional profile  16  is flared out from first side  730  of longitudinal section  721 . A second section  743  and a third second  744  of the substantially V-shaped cross-sectional profile  16  are adjacent to opposite ends of first section  742  of the V-shaped cross-sectional profile  16 . Second section  743  and third section  744  of the substantially V-shaped cross-sectional profile  16  are flared out from second side  733  of longitudinal section  721 . 
     Group  726 , moreover, has a first outer edge  734  and a second outer edge  735 . An edge-side web with a substantially hook-shaped cross-sectional profile  18  is disposed in the areas of both outer edges  734 ,  735 . The edge-side webs with the substantially hook-shaped cross-sectional profile  18  each have a first leg  745  and a second leg  746 , whereby first leg  745  is about double the length of second leg  746 . First legs  745  have a first section, which is disposed substantially facing mirror axis S 8  and which is flared out from second side  733  of longitudinal section  721 , and a second section, which is disposed substantially facing away from mirror axis S 8  and which is flared out from first side  730  of longitudinal section  721 . 
     A further web with a substantially hook-shaped cross-sectional profile  18  is disposed in each case in the two sections  727 ,  728  between the edge-side webs with the substantially hook-shaped cross-sectional profile  18  and the web disposed in the area of mirror axis S 8  and having a substantially V-shaped cross-sectional profile  16 . The two further webs with a substantially hook-shaped cross-sectional profile  18  each have a first leg  747  and a second leg  748 , whereby first leg  747  is about double the length of second leg  748 . First legs  747  have a first section, which is disposed substantially facing mirror axis S 8  and which is flared out from second side  733  of longitudinal section  721 , and a second section, which is disposed substantially facing away from mirror axis S 8  and which is flared out from first side  730  of longitudinal section  721 . 
       FIG. 18  shows a further exemplary embodiment of a group  826  of webs arranged on a longitudinal section  821  of a fin of a fin element of the invention. Longitudinal section  821  has a first side  830  and a second side  833  opposite to first side  830 . Group  826  has a mirror axis S 9 , which divides group  826  into two sections  827 ,  828 , formed mirror-symmetric to one another and adjacent to one another at mirror axis S 9 . 
     A web with a substantially V-shaped cross-sectional profile  16  is disposed at mirror axis S 9 . The two legs of the V-shaped cross-sectional profile  16  form an angle whose vertex is located on mirror axis S 9 . In this case, a first section  842  of the V-shaped cross-sectional profile  16  is flared out from second side  833  of longitudinal section  821 . A second section  843  and a third second  844  of the substantially V-shaped cross-sectional profile  16  are adjacent to opposite ends of first section  842  of the V-shaped cross-sectional profile  16 . Second section  843  and third section  844  of the substantially V-shaped cross-sectional profile  16  are flared out from first side  830  of longitudinal section  821 . 
     A web with a substantially Z-shaped cross-sectional profile  19  is disposed adjacent to sections  843 ,  844 . The Z-shaped cross-sectional profile has two substantially hook-shaped subsections  838 ,  839 , each of which are flared out in sections from first side  830  and from second side  833  of longitudinal section  821 . 
     Group  826 , moreover, has a first outer edge  834  and a second outer edge  835 . A web with a substantially hook-shaped cross-sectional profile  18  is disposed at outer edges  834 ,  835 . In this case, the two webs with a substantially hook-shaped cross-sectional profile  18  are flared out in sections from first side  830  and from second side  833  of longitudinal section  821 . 
     The webs disposed in the area of one of outer edges  834 ,  835  and having a substantially hook-shaped cross-sectional profile  18  each have an end section facing outer edges  834 ,  835 , said section being disposed substantially parallel to depth direction T. 
       FIG. 19  shows a further exemplary embodiment of a group  926  of webs arranged on a longitudinal section  921  of a fin of a fin element of the invention. The exemplary embodiment shown in  FIG. 19  corresponds substantially to the exemplary embodiment shown in  FIG. 16 . In the exemplary embodiment shown in  FIG. 19 , in contrast to the exemplary embodiment shown in  FIG. 16 , the two webs disposed in the area of outer edges  934 ,  935  and having a substantially hook-shaped cross-sectional profile  18  have a section  950 , flared out from first side  930  of longitudinal section  921 , and a section,  951  flared out from second side  933  of longitudinal section  921 . 
       FIG. 20  shows an enlargement of the detail, shown in  FIG. 6 , of a fin element  201  according to  FIG. 5 . The cut is made here also in longitudinal direction L of fin element  201 . Fin element  201  in longitudinal direction L of fin element  201  has fins  202  which are arranged in rows and through which an airflow can flow in depth direction T perpendicular to longitudinal direction L of fin element  201 . 
     Fin element  201  has a first long side  205  and a second long side  206  opposite to first long side  205 . Longitudinal sections  204  of fins  202  are arranged running obliquely from first long side  205  to second long side  206  or from second long side  206  to first long side  205 . Connecting sections  207  each connect two adjacent longitudinal sections  204  and are each disposed in the area of first long side  205  or second long side  206 . Connecting sections  207  can be connected frictionally, positively locking, and/or materially to the heat transfer elements. Preferably gluing or soldering methods are used for this purpose. In the exemplary embodiment shown in  FIG. 20 , connecting sections  207  are arranged angled to longitudinal sections  204 . Longitudinal sections  204  of fins  202  have gills  203  which are arranged in rows along longitudinal sections  204 . 
     Longitudinal sections  204  of two adjacent fins  202 , said sections being disposed facing one another, are each connected together in the area of first long side  205  or second long side  206  of fin element  201 . This reduces the length of the fin distance X 1  between the two longitudinal sections  204 , facing one another, toward first long side  205  or toward second long side  206  of fin element  201 . In the area of connecting sections  207  of adjacent fins  202 , adjacent fins  202  are in contact and fin distance X 1  approaches 0. 
       FIG. 21  shows a view, cut along the depth direction, of webs  9  and slots  10  of a fin element formed according to  FIGS. 1, 2, and 7 . An air velocity profile of the air flowing along web surfaces  11  or surface sections  12 ,  13  is placed above the sectional view. The velocity profile shows that the air when flowing along web surfaces  11  or surface sections  12 ,  13  changes its direction and its velocity at the vertices S due to the angled arrangement of the surface sections. This leads overall to a homogenization of the air velocity profile and also the air temperature profile. The result is a high heat transfer performance, combined with a low pressure loss on the part of the airflow flowing through the fin element. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.