US20100116466A1

US20100116466A1 - Axial Heat Exchanger for Regulating the Temperature and Air Comfort in an Indoor Space

Info

Publication number: US20100116466A1
Application number: US12/266,591
Authority: US
Inventors: Jerzy Hawranek
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-07
Filing date: 2008-11-07
Publication date: 2010-05-13

Abstract

The present invention offers an axial heat exchanger for exchanging heat between a gas medium and a fluid or liquid medium. The axial heat exchanger comprises a longitudinal and substantially axially extended outer channel that is adapted to enclose a flow of a first gas medium. The heat exchanger also comprises a plurality of substantially parallel inner channels that are adapted to enclose a flow of a second liquid medium. The inner channels are arranged inside the outer channel so as to extend substantially axially along the inside of said outer channel for enabling a transfer of heat between said first gas medium and said second liquid medium. At least one of the inner channels is joined with at least one elongated sheet. The sheet is arranged to extend substantially axially along the inner channel so as to substantially coincide with the direction of flow of the first gas medium through the outer channel. The sheet has a first component directed from the centre of the outer channel to the wall of the outer channel and a second component extending from the end of the first component along the wall of the outer channel.

Description

FIELD OF THE INVENTIONS

The present invention relates to an axial heat exchanger for exchanging heat between two mediums, preferably a gas medium and a liquid medium and most preferably air and water. More particularly, the invention relates to a heat exchanger for regulating the air temperature and the air comfort in a defined space, preferably in an indoor space and more particularly to a heat exchanger that is suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference.

BACKGROUND OF THE INVENTIONS

1. Introduction
Transfer of heat is a very common operation in connection with natural and human induced activities. Heat transfer mainly depends on three different mechanisms, namely conduction, convection and radiation.
Heat transfer by conduction is essentially characterized by no observable motion of matter. In metallic solids there is motion of unbound electrons and in liquids there is transport of momentum between molecules and in gases there is molecular diffusion (the random motion of molecules). Heat transfer by convection is essentially a macroscopic phenomenon that arises from the mixing of fluid elements, wherein natural convection may be caused by differences in density and forced convection may be caused by mechanical means. Heat transfer by radiation is essentially characterized by the presence of electromagnetic waves. All materials radiate thermal energy. When radiation falls on a second body it will be transmitted reflected or absorbed. Absorbed energy appears as heat in the body.
Transfer of heat in most heat exchangers takes place mainly by conduction and possibly convection as heat passes through one or several layers of material to reach a flow of heat absorbing fluid or gas. However, other transferring mechanisms may be involved to some extent. The layer or layers of material are normally of different thicknesses and with different thermal conductivities. Consequently, knowledge of the overall heat transfer coefficient is essential in the design of a heat exchanger. With known overall heat transfer coefficient the required heat transfer area is calculated by an integrated energy balance across the heat exchanger.
Heat exchangers are available in a number of various designs. The most common types are the tubular heat exchanger, the plate heat exchanger and the scraped surface heat exchanger. The choice of construction material differ depending on application. In the food industry the predominant materials are stainless or acid proof steel or even more exotic materials like titanium, the latter typically for fluids containing chlorides. In other industries heat exchangers made out of mild steel may be sufficient.
Plate heat exchangers are often used on low-viscous applications with moderate demands on operating temperatures and pressures, typically below 150° C. and 25 bars. Gasket material is chosen to withstand the operating temperature at hand and the constituents of the processing fluid. In the food industry plate heat exchangers are typically used for milk and juice pasteurisers operating at temperatures below 100° C. and pressures below 15 bars.
Tubular heat exchangers are typically used in applications where the demands on high temperatures and pressures are significant. Also, tubular heat exchangers are employed when the fluid contains particles that would block the channels of a plate heat exchanger. In the food industry tubular heat exchangers are typically used for milk and juice sterilisers operating at temperatures up to 150° C. Tubular heat exchangers are also used for moderate to high-viscous and particulate products, e.g. tomato salsa sauce, tomato paste and rice puddings. In some of these cases the operating pressure can exceed 100 bars. Particles up to 10-15 mm in size can be treated in tubular heat exchangers without problems.
Scraped surface heat exchangers are used in applications where the viscosity is very high, where big lumps are part of the fluid or where fouling problems are severe. In the food industry scraped surface heat exchangers are used e.g. on products like strawberry jam with whole strawberries present.
The treatment in the heat exchanger is so gentle and the pressure drop so low that the berries will pass the system with only very little damage. The scraped surface heat exchanger is, however, the most expensive solution and is therefore used only when plate heat exchangers and tubular heat exchangers would not perform adequately.
2. Related Art
US2006231242 disclosed an axial heat exchanger that is suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference, and they are particularly unsuitable as heat exchangers for regulating the temperature of air slowly flowing through the exchanger for the purpose of regulating the temperature and air comfort in a defined space, preferably in an in door space. This heat exchanger is provided with an elongated and substantially axially extending outer channel that is adapted to enclose a flow of a first gas medium. The heat exchanger also comprises a plurality of substantially parallel inner channels that are adapted to enclose a flow of a second liquid medium. The inner channels are arranged inside the outer channel so as to extend substantially axially along the inside of said outer channel for enabling a transfer of heat between said first gas medium and said second liquid medium. The heat transfer is improved to some extent as the number of inner channels increases and it is further improved in that at least one of the inner channels is joined with at least one elongated sheet. The sheet is arranged to extend substantially axially along the inner channel so as to substantially coincide with the direction of f low of the first gas medium through the outer channel.

SUMMARY

The heat exchanger disclosed below provides for an increased heat exchanging surface. The sheet members or fins that are connected to the inner channels are shaped to exploit the available space in a better way and fit better into a tubular outer channel. Due to the shape and positioning of the fins the amount of dead space—in particularly near the wall of the tubular outer channel—is reduced. The proposed fin structure can easily be applied to existing heat exchangers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an inner heat exchanging structure 100 according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the cross-section of the inner heat exchanging structure 100 in FIG. 1B substantially cut along the line X-X.

FIG. 3 shows a plurality of axial heat exchangers A1 according to the first embodiment of the invention shown in FIGS. 1B and 2.

FIG. 4 is a perspective view of an inner heat exchanging structure 100 according to a second embodiment of the present invention.

FIG. 5 shows a schematic cross-section of the heat exchanger A1 shown in FIGS. 1 and 2.

FIG. 6 shows a schematic cross-section of the heat exchanger according to a third embodiment of the present invention.

FIG. 7 shows a schematic cross-section of an axial heat exchanger according to a fourth embodiment of the present invention.

FIG. 8 shows a schematic cross-section of an axial heat exchanger according to a fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTIONS

FIG. 1 is a perspective view showing an inner heat exchanging structure 100 according to a first embodiment of the present invention. The inner heat exchanging structure 100 in FIG. 1 is also shown in FIG. 2, substantially cut along the line X-X in FIG. 1 to uncover a perspective view of the cross-section of the inner heat exchanging structure 100. The inner heat exchanging structure 100 is shown in FIG. 2 arranged inside an outer channel structure 200. The outer channel structure 200 and the enclosed inner heat exchanging structure 100 in FIG. 2 forms an axial heat exchanger A1 according to a first embodiment of the present invention. The outer channel may be received in an insulation body (not shown).
The exemplifying outer channel structure 200 shown in FIG. 2 has a cylindrical or tubular shape. The inner diameter of the exemplifying outer channel 200 may be approximately 100-500 millimeters, more preferably approximately 100-300 millimeters and most preferably approximately 100-200 millimeters. The wall of the outer channel 200 may have a thickness of a few millimeters, preferably less than two millimeters. Other wall thicknesses and other diameters are clearly conceivable. The length of the exemplifying outer channel 200 may be approximately 400-3000 millimeters, more preferably approximately 500-2000 millimeters and most preferably 600-1500 millimeters, though other lengths are clearly conceivable. The shape and cross-section of the outer channel structure 200 may evidently differ, as long as it encloses the inner heat exchanging structure 100 in a way that enables a first medium to flow along the axial heat exchanger A1 between the sheets (fins) 110 of the inner heat exchanging structure 100 and the wall of the outer channel structure 200. The outer channel structure 200 is adapted to contain a flow of a gas medium, preferably air or a similar gas. The medium channels 210 are also indicated in the schematic cross-section of the axial heat exchanger A1 shown in FIG. 5. It can be observed that the medium (e.g. air) may flow in one or the other of the two possible directions inside the outer channel 200.
The wall of the outer channel structure 200 in FIG. 2 is preferably made of a light weight material, e.g. a light metal as aluminum or a plastic material, a carbon fiber material or similar. It is also preferred that the wall of the outer channel structure 200 is comparably thin. A canvas, a cloth, a foil, a film or any similar suitable thin sheet material may therefore form the outer channel structure 200. The sheet material may e.g. be made of metal, rubber, plastic or a fabric or similar. Consequently, a preferred embodiment of the outer channel structure 200 may e.g. have a wall that is made of a plastic cloth, a plastic foil or some similar substantially medium-tight (e.g. air-tight) cloth material or similar having a small weight. The sheet material is preferably wrapped or otherwise arranged around the outside edges of the inner heat exchanging structure 100 so as to form an outer channel structure 200 that encloses the inner heat exchanging structure 100. The sheet material may e.g. be a shrink wrap or even a shrinking tubing that is heated to shrink and fit on the outside of the inner heat exchanging structure 100.
The enclosing outer channel 200 has now been discussed in some detail and the attention is again directed to the inner heat exchanging structure 100 of the heat exchanger A1 shown in FIG. 2. It is clear from FIG. 2 that the heat exchanging structure 100 comprises five fins 110 shaped as thin sheets. At least four of these fins 110 are clearly shown in FIG. 1. The sheet or fin 110 may have a thickness of some tenths of a millimeter to a few millimeters, preferably less than two millimeters.
The sheets or fins 110 in FIG. 1-2 extend in a first axial direction that is substantially parallel to the axial extension and/or the centre axis X1 of the inner heat exchanging structure 100 in FIG. 1 and the outer channel 200 in FIG. 2. The fins 110 extend substantially along the whole length of the inner heat exchanging structure 100. As can be seen in FIG. 2, the fins 110 of the heat exchanging structure 100 arranged in the axial heat exchanger A1 are extending in the axial extension of the outer channel structure 200, so as to substantially coincide with the direction of flow of a medium that flows within the enclosing outer channel structure 200.
The sheets or fins 100 have first component 112 and a second component 114. The first component 112 of the sheets or fins 110 in FIGS. 1 and 2 extends in a radial direction, in addition to extending in an axial direction as previously explained. The radial direction extends substantially outwards from the centre or centre axis of the heat exchanging structure 100 towards the outer channel structure 200. This extends ends at a distance from the outer channel wall. The second component 114 of the sheets or fins 110 extends along the wall of the outer channel 200, i.e. substantially tangentially from the end of the first component 112 near the outer channel structure. The second component is in the shown embodiment curved, with a curvature identical or similar to the curvature of the outer channel. However, the second component could also be a not curved panel, as disclosed with the second embodiment below, or could be formed by two or more panels that are connected to one another at an angle (not shown) to approximate the curve of the outer wall.
Preferably, the first component 112 and the second component 114 of the sheet or fin 110 are formed from a singe piece of sheet material by bending or other shaping process. Alternatively, the first 112 and second component are made from two parts that are connected to one another by suitable know techniques.
The second component 114 leaves a small gap to the channel structure 200.
Even though the exemplifying fin 110 in the heat exchanging structure 100 in FIG. 2 is a straight rectangular sheet arranged in parallel with the extension of the outer channel 200, certain embodiments of the present invention may have sheets or similar that are curved or twisted. For example, sheets that extend in a spiral pattern or similar along the inside of the outer channel structure 200 or similar, or sheets that form one or several medium channels—comparable to the medium channels 210 in FIGS. 2 and 6 a—which channels e.g. extend in a spiral shaped structure along the inside of an axial outer channel 200 or similar.
The fins 110 in FIGS. 1-2 are made of a heat conductive material, preferably a metal and more preferably a lightweight metal as aluminum or similar. The material can be provided with indentations or the like (not shown) to improve the stability and rigidity of the sheet and to enhance turbulence in the flow along the surface of the sheets or fins 110.
Each fin 110 is joined with an inner small, straight and preferably tubular channel 120 that is positioned in the middle or near the middle of the fin 110. The wall of the exemplifying inner channel 120 may have a thickness of a few tenths of a millimeter to a few millimeters, preferably less than one millimeter, whereas the inner diameter of the inner channel 120 may be approximately 4-20 millimeters, preferably approximately 5-15 millimeters and most preferably approximately 6-10 millimeters. Other wall thicknesses and other diameters are clearly conceivable. The inner channel 120 is preferably made of the same heat conductive material as the fin 110 or a similar material that enables a good transport of heat between the inner channel 120 and the fin 110. The straight inner channel 120 extends along the entire rectangular fin 110 from one short end to the other. The inner channel 120 is preferably adapted to contain a flow of a fluid or liquid medium, preferably water.
It should be added that the present invention is not limited to the channels 120 in FIGS. 1-2. On the contrary, a channel may have a cross-section that is circular or oval as well as partly circular and/or partly oval, or that is triangular, quadratic, rectangular or otherwise polygonal, or a cross-section that is a combination of these examples. Moreover, a fin 110 may be joined with a channel in other positions and/or according to other patterns. For example a channel may be joined with a fin 110 so as to extend along the fin 110 in an s-shaped pattern from one short end to the other. A sheet or a fin 110 or similar may also be provided with two or more channels without departing from the scope of the invention.
The perspective view in FIG. 1 shows that the heat exchanging structure 100 is provided with a lower distribution manifold 130 extending radially out of the heat exchanging structure 100. The lower distribution manifold 130 is connected to a lower distribution channel 140 that in turn is connected to the lower end of each channel 120 in the fins 110 by means of curved lower tubular connecting channels 122 arranged at the lower end of the heat exchanging structure 100. The upper end of each channel 120 in the fins 110 is in turn connected to an upper distribution hub 150 by means of a curved upper tubular connecting channel 121 arranged at the upper end of the heat exchanging structure 100. The upper collecting hub 150 is in turn connected to a center channel 160 that extends axially downwards from the collecting hub 150 substantially coinciding with the centre axis of the heat exchanging structure 100. The wall of the exemplifying center channel 160 may have a thickness of a few tenths of a millimeter to a few millimeters, preferably less than two millimeters, whereas the inner diameter of the center channel 160 may be approximately 20-100 millimeters, preferably approximately 25-75 millimeters and most preferably approximately 25-50 millimeters. Other wall thicknesses and other diameters are clearly conceivable. The lower end of the center channel 160 has a curved section 161 that terminates the center channel 160 in a center-channel manifold 170, which extends radially out of the heat exchanging structure 100 at the lower end, preferably below the fins 110 and preferably below the lower distribution manifold 130.
Such properties as the diameter and wall thickness of the outer channel 200, the diameter and wall thickness of the inner channels 120, the shape and thickness of the fins 110, the choice of material for the outer channel 200, the inner channels 110 and the fins 110 can easily be adapted in a well known manner by a person skilled in the art, so as to fit the application in question, e.g. depending on the temperature, the density, the viscosity, the pressure, the flow rate etc. of the medium that is supposed to flow through the outer channel 200 and the medium that is supposed to flow through inner channels 110.
Exemplifying Cross-Sections
As indicated above, the fins 110 or sheets or similar in an axial heat exchanger A1 according to an embodiment of the present invention may be arranged according to different patterns having different cross-sections, wherein the fins 110 or sheets or similar are extending in the axial extension of an outer enclosing channel 200, so as to substantially coincide with the direction of flow of a medium that flows within the outer channel 200.
A small number of schematic cross-sections are given below to illustrate the variety of possible cross-sections.
FIG. 5 shows a schematic cross-section of the previously discussed heat exchanger A1 in FIGS. 1-2, wherein the same numerals denote the same objects in all the FIGS. 1-2 and 6 a.
FIG. 6 shows a schematic cross-section of another possible pattern for arranging the fins or sheets within an outer channel of an axial heat exchanger according to an embodiment of the present invention. This third embodiment has no central inner channel 60.
FIG. 7 shows a schematic cross-section of an axial heat exchanger according to fourth that is essentially the same as the previously discussed axial heat exchanger A1 shown in FIGS. 1-2. However, the outer channel 200 of the heat exchanger A1 with a circular cross section has been replaced in FIG. 6 d by an outer channel structure 600 with a hexagonal cross section. The shape of the second components of the sheets 110 has been adapted correspondingly.
FIG. 8 shows the same axial heat exchanger as the one shown in FIG. 7, with the exception that the axial heat exchanger in FIG. 8 has four fins 110 instead of six fins 110 as in the heat exchanger shown in FIG. 7. It is especially advantageous to provide the rectangular axial heat exchanger in FIG. 6 f with an outer rather thick protective cover consisting of a foamed plastic or a cellular plastic. This offers superior properties for transportation and storing. The protective cover may remain on the heat exchanger after installation of the exchanger.
A few schematic cross-sections have been briefly been discussed to illustrate the variety of possible embodiments of the present invention. However, other embodiments of the axial heat exchanger of the present invention may have fins or sheets that are arranged according to other suitable patterns that may or may not extend around the centre axis of an inner heat exchanging structure (e.g. the centre axis of the inner heat exchanging structures 100, 300), e.g. according a triangular, quadratic, rectangular, circular or semicircular pattern.

Operation and Use of Axial Heat Exchangers According to Embodiments of the Invention

A first medium is supplied to the axial heat exchanger A1 trough the lower distribution manifold 130 and the lower distribution channel 140, from which the media flows into the channels 120 in the fins 110 and on to the upper distribution hub 150 and from there back through the center channel 160 that terminates in the center-channel manifold 170 from which the medium will be discharged from the heat exchanger A1. A second medium is supplied so as to flow through the heat exchanger A1 along the axial channel or channels 210 arranged in the space between the outer channel structure 200 and the inner heat exchanging structure 100. Heat will consequently be exchanged between the first and second media via the fins 110 arranged on the heat exchanging structure 100, provided that there is a temperature difference between the two media.
The first medium may flow in a direction that is opposite to the direction indicated above. The second media may flow by means of natural convection through the channel or channels 210, especially in embodiment wherein the inner diameter of the outer channel structure 200, is comparably large, e.g. 100-200 millimeters or more. In other words, some embodiments of the present invention may not need a fan or similar to propel the second media, whereas a fan or similar may be preferred or needed in other embodiments.
Axial heat exchangers according to the present invention can be used in a variety of different applications and in a variety of structures. In particular, a plurality of axial heat exchangers according to the invention may particularly be used connected in series or connected in parallel.
FIG. 4 shows a plurality of axial heat exchangers A1 according to the first embodiment of the invention as discussed above in connection with FIGS. 1-2. The heat exchangers A1 have been arranged in parallel to enable a substantially simultaneous flow of a first medium (preferably air) through each the heat exchanger A1 along the medium channel or channels 210 as discussed above in connection with FIG. 2. The heat exchangers A1 must not be arranged side by side along a straight line as in FIG. 5 b. On the contrary, the heat exchangers A1 may be arranged side by side in a circle or in a semi-circle, or in a square or according to some other polygonal pattern.
Each parallel heat exchanger A1 in FIG. 5 b have been coupled to a supply channel arrangement extending along the parallel heat exchangers A1 for providing each exchanger with a second medium (preferably water). Accordingly, the lower distribution manifold 130 of each heat exchanger A1 has been coupled to a first supply channel 710, whereas the center-channel manifold 170 of each heat exchanger A1 has been coupled to a second supply channel 720. The supply channel arrangement 710, 720 and the medium tempering source 700 shown in FIG. 5 b can be the same as those previously described in connection with FIG. 5 a.
Dashed lines in FIG. 3 illustrate a box-like distribution channel 730. Such a shared distribution channel 730 or similar may be arranged to cover one end of every parallel heat exchanger A1 for enabling a substantially parallel and possibly forced flow of a first medium through each parallel heat exchanger A1. The distribution channel 730 in FIG. 5 b is arranged at the upper end of the parallel heat exchangers A1. It should be emphasized that the lower ends may be covered instead or as well. The upper ends in FIG. 5 b may protrude a suitable distance into apertures (not shown) that have been arranged in the long-side of the box-like distribution channel 730 facing towards the parallel heat exchangers A1. The parallel heat exchangers A1 can be substantially sealed towards the outer side of the distribution channel 730 and the heat exchangers A1 are preferably fully open towards the inside of the distribution channel 730. The first medium can be provided to the distribution channel 730 from a supply channel (not shown) connected to the distribution channel 730. The arrow 740 in FIG. 5 b indicates a possible direction of flow of the first medium into the distribution channel 730.
FIG. 4 illustrates a second embodiment of the invention, which is a variation of the first embodiment with the main difference being in the second component 114 of the sheets 10 being not curved, i.e. plainer plates.
According to an embodiment, the heat exchanger is provided with only a single, preferably central inner channel.
The sheet member 110 has been shown as an L-shaped components but a T-shape is also within the scope of the invention.
The large heat exchanging surfaces that can be obtained in an axial heat exchanger according to the present invention makes it possible to operate with low temperature differences between the first medium and the second medium. For example, embodiments of the present invention can operate with a comparable low difference in temperature between heating water and heated air flowing through and out from the exchanger or exchangers for creating a comfortable temperature in a defined space, e.g. in a room or a similar indoor space. A heat exchanger according to an embodiment of the present invention can certainly be adapted to use air having an input temperature as low as −18° C. to produce air having an output temperature as high as +18° C. by utilizing heated water or similar having an temperature as low as +35° C. In a heat exchanger according to the present invention can generally be adapted to enable heating of indoor spaces and similar by utilizing heated water having a temperature below +40° C. This should be compared to the water temperature supplied to radiators in ordinary hot-water heating systems, which in general is approximately +55° C. and which may be as high as +75° C. in a cold winter day when the outdoor temperatures is as low as e.g. −18° C.
The various aspects of what is described above can be used alone or in various combinations. The teaching of this application is preferably implemented by a combination of hardware and software, but can also be implemented in hardware or software. The teaching of this application can also be embodied as computer readable code on a computer readable medium. It should be noted that the teaching of this application is not limited to the use . . . .
The teaching described above has numerous advantages. Different embodiments or implementations may yield one or more of the following advantages. It should be noted that this is not an exhaustive list and there may be other advantages, which are not described herein. One advantage of the teaching of this application is that it provides for a heat exchanger that suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference that has an increased heat exchange surface. Another advantage of the teaching of this application is that it provides for a heat exchanger that is suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference with a flange system that fits better into a tubular outer channel. Yet another advantage of the teaching of this application is that that it provides for a heat exchanger that is suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference that allows for heat exchange with fluid that is not flowing near a radial fin, i.e. shorter average distance between the metal and the gas medium without causing too much friction. A further advantage of the teaching of this application is that that it provides for a heat exchanger that is suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference that is easy to retrofit to existing heat exchangers. Another advantage of the teaching of this application is that that it provides for a heat exchanger that is suitable for exchanging heat between a slowly flowing gas medium and a flow of a fluid or liquid medium having a low temperature difference that is constructed with few joints or creases.
Although the teaching above has been described in detail for purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the scope of the teaching.
The term “comprising” as used in the claims does not exclude other elements or steps. The term “a” or “an” as used in the claims does not exclude a plurality. The single processor or other unit may fulfill the functions of several means recited in the claims.

Claims

1. An axial heat exchanger (A1, A2) comprising:

an axially extending outer channel (200) having a wall adapted to enclose a flow of a first gas medium; and

a plurality of elongated substantially parallel inner channels (120) adapted to enclose a flow of a second liquid medium,

which inner channels (120) are arranged inside the outer channel (200) so as to extend substantially axially inside said outer channel (210) for enabling a transfer of heat between said first gas medium and said second liquid medium, wherein at least one inner channel (120) is joined with at least one elongated sheet (110); the elongated sheet (110) extends substantially axially along said inner channel (120) so as to substantially coincide with the direction of flow of the first gas medium through the outer channel (200) and wherein said sheet comprises a first component (112) extending from a central portion of the outer channel towards the wall of the outer channel and a second component (114) extending from the end of the first component near the wall of the outer channel in a direction substantially along the wall of the outer channel.

2. An axial heat exchanger (A1) according to claim 1, wherein said outer channel (200) is tubular and said first component (112) is substantially disposed radially and said second component is substantially disposed tangentially relative to the outer channel (200).

3. An axial heat exchanger (A1) according to claim 2, wherein the second component (114) is curved or creased to substantially match the curve of the outer channel (200).

4. An axial heat exchanger (A1) according to claim 2, wherein said inner channels (120) are arranged on an imaginary circle that is concentric with the outer channel (200).

5. An axial heat exchanger (A1) according to claim 2, wherein said first component (112) and said second component (114) are made from one piece of material.

6. A heat exchanging system comprising at least two axial heat exchangers (A1) according to claim 5, wherein:

said axial heat exchangers (A1) are serially coupled to enable a flow of a first gas medium through the outer channel (200) of a first heat exchanger (A1) into the outer channel (200) of the next heat exchanger (A1) and through each serially coupled heat exchanger (A1); and

said axial heat exchangers (A1) have a first distribution arrangement (122, 130, 140) and a second distribution arrangement (121, 150, 160, 170) adapted to be coupled to a supply channel arrangement (710) that extends substantially along the serially coupled heat exchangers (A1) for providing a flow of a second liquid medium through the inner channels (120) of each axial heat exchanger (A1).

7. A heat exchanging system comprising at least two axial heat exchangers (A1) according to claim 6, wherein:

said axial heat exchangers (A1) are coupled in parallel to enable a substantially simultaneous and parallel flow of a first gas medium through the outer channel (200) of the parallel heat exchangers (A1); and

each axial heat exchanger (A1) have a first distribution arrangement (122, 130, 140) and a second distribution arrangement (121, 150, 160, 170) adapted to be coupled to a supply channel arrangement (710) that extends substantially along the coupled heat exchangers (A1) for providing a flow of a second liquid medium through the inner channels (120) of each axial heat exchanger (A1).

8. A heat exchanging system according to claim 7, wherein at least one end of the parallel heat exchangers (A1) is coupled to a shared parallel distribution arrangement (740) that is arranged for enabling a substantially simultaneous parallel and possibly forced flow of a first gas medium through the parallel heat exchangers (A1).