HEAT EXCHANGER, METHOD FOR ITS PRODUCTION AS WELL AS SEVERAL DEVICES COMPRISING SUCH A HEAT EXCHANGER

Abstract

Heat exchanger 1 for removing heat from a medium with at least one serpentine-shaped wing tube 20 arranged in a housing, the linear wing section 30 of which is arranged such that the wing 24 of the wing section 30 encloses an angle in the range of 10°≦α≦30° with a flow direction S.

Description

1. FIELD OF THE INVENTION

The present invention is related to a heat exchanger for removing heat from a medium, a serpentine-shaped wing tube as an essential part of such a heat exchanger, a method for producing such a serpentine-shaped wing tube as well as a method for producing the above-mentioned heat exchanger.

2. BACKGROUND OF THE INVENTION

Heat exchangers are generally known in the prior art. They are used in cooling systems and air conditioners or air conditioning systems to withdraw heat from a heated medium and to dissipate it to the surrounding. Based on this functionality, the heat exchangers are also denoted as condenser or evaporator based on the transformation of the medium to be cooled therein.

Such heat exchangers usually consist of at least two side walls arranged oppositely to each other and between which a grid structure is arranged which consists of tubes. These tubes form a flow path through which a medium to be cooled may be directed. The outside of the tubes is for example flowed around by an air flow which is directed to the tube arrangement by means of a fan.

Depending on the type of tube arrangement of the tubes, which is exposed to the cooling air or gas flow, the medium directed within the tubes is cooled. For increasing the heat absorption of the flowing around medium, for example the flowed around tube surface is increased. For this purpose, the tubes of the heat exchanger are provided with radially protruding wings, so-called wing tubes, as they are exemplarily disclosed in WO 2009/068979. Such wing tubes consist of thermally conductive metal or alloys thereof as for example steel, steel alloy, copper, copper alloy, aluminum and aluminum alloys. The wing tubes are either produced by rolling or by metal extrusion.

In the heat exchanger of WO 2009/068979, several linear wing tubes are arranged between two opposite side walls. In the portion of the sidewalls, the linear wing tubes are connected to each other via curved coupling parts, respectively. Such coupling parts are soldered individually to the two linear wing tubes to be connected for producing a liquid-tight or gas-tight connection between the two linear wing tubes. This production method of the heat exchanger is, due to the plurality of work steps, labour-intensive and thus expensive. Further, the linear wing tubes are arranged even relative to each other which leads to a shadowing of adjacent wing tubes and thus to a reduced efficiency of the heat exchanger. A further disadvantage is that in a too close-meshed arrangement of the tubes of the heat exchanger a contamination may occur which has to be removed regularly. This is especially obvious when lamellar structures are used in the heat exchanger. Accordingly, high maintenance efforts are required, respectively, in order to clean the heat exchanger regularly.

It is thus the object of the present invention to provide a heat exchanger with improved efficiency, a lower amount of maintenance required and which is based on a simplified production method compared to the prior art.

3. SUMMARY OF THE PRESENT INVENTION

The present invention comprises a heat exchanger for removing heat from a medium, wherein the heat exchanger has the following features: at least two outer walls defining an opening therebetween by means of which a gas flow is directable into a flow direction, at least a first and a second serpentine-shaped wing tube consisting of a tube and at least two wings, which protrude radially therefrom, preferably oppositely, wherein the wing tube has at least two linear wing sections coupled via wing-less curved tube sections, respectively, the wing sections of the at least first and second wing tube are arranged in at least one tube plane per wing tube, respectively, wherein the tube plane is orientated vertically to the flow direction, wherein the wings of the wing sections of at least the first wing tube are arranged in at least a plurality of first wing planes arranged parallel to each other, which are arranged in a defined angle in the range of 10°≦α≦30° with respect to the flow direction.

The construction of the heat exchanger according to the invention is based on at least one wing tube, which is curved in the shape of a wavy line or a serpentine, through which a medium to be cooled may be directed. This serpentine-shaped curved wing tube comprises linear wing sections, which are exposed to the flowing around and cooling medium in the future heat exchanger, as well as curved wingless tube sections, which couple two adjacent linear wing sections to each other. As the serpentine shaped wing tube is preferably formed integrally, according to one embodiment by the extrusion of aluminum or an aluminum alloy, also the linear wing sections and the wingless curved tube sections are coupled integrally to each other and thus require no additional coupling methods, such as for example hard soldering, during the production of the heat exchanger. Further, preferably the linear wing sections of the serpentine-shaped wing tube are arranged in at least one tube plane perpendicular to the flow direction for ensuring an orderly grid structure of the heat exchanger and thus a flowing of the cooling medium against a surface of the heat exchanger as large as possible.

For providing a sufficient large surface by the serpentine-shaped wing tube for flowing against by the cooling medium, the wings of the wing sections of the serpentine-shaped wing tube are aligned in a defined angle with respect to the flow direction of the inflowing cooling medium or in a defined angle with respect to the normal of the tube plane in which the wing sections are arranged. This defined angle of the wings of the wing sections reaches from a range of 10°≦α≦30°. By means of the variation of the angle of the wings of the wing sections, the size of the flowed against surface of the heat exchanger is adjustable on the one hand. Further, it is possible to provide equal or different flow conditions within the heat exchanger. Due to this variability, for example a shadowing of wing sections arranged downstream in flow direction may be reduced, which in turn improves the efficiency of the heat exchanger.

According to a preferred embodiment of the present invention, the wing sections of the at least first and second serpentine-shaped wing tube of the heat exchanger are arranged in two tube planes per wing tube such that adjacent wing sections of a wing tube are arranged in different tube planes. Further, it is preferred to arrange the wings of the wing sections of the second wing tube in at least a plurality of second wing planes, which are arranged parallel to each other and which are arranged in a second defined angle in the range of 10°≦β≦30° with respect to the flow direction. In a further preferred embodiment of this arrangement, the first or the second or the first and the second defined angle lie in a range of 10°≦α, β≦20°, further preferred in a range of 12°≦α, β≦18° and even more preferred at an angle of 15°.

Depending on the above-mentioned angle ranges, the surface arranged against the flowing medium, for example air, varies in its size and also the turbulence of the inflowing cooling medium in the heat exchanger varies so that the withdrawal of heat from the medium directed in the wing tubes is successively increased. It has become apparent that an increased efficiency of the heat exchanger may be achieved with a setting of the wings of the wing sections in an angle of 12°-18° and even better of 15° with respect to the flow direction or the normal of the tube plane. In general, already adequate heat exchanger results are achievable in an angle range of the wing sections of 10°-30°.

In another arrangement of the above-described embodiments it is further preferred to provide a plurality of wings, which protrude in radial direction and are formed curved out of the wing planes. This preferred shaping of the wings, which is similar to an aircraft wing when viewed in the cross sectional side view, supports the heat exchange with the medium flowing against the wing tube. In this context, it is especially preferred that the wings of the wing tube which are arranged opposite to each other are curved in opposite directions. For further supporting the heat exchange between the surrounding and the medium contained in the wing tube it is also preferred to provide a plurality of recesses on an inner side of the tube of the wing tube which enlarge the surface of the inner side of the tube of the wing tube. Preferably, these recesses on the inner side of the tube extend in longitudinal direction of the wing tube whereas webs, which are arranged adjacent to these recesses, protrude radially into the interior of the wing tube. These webs may have different shapes as for example a square or a rounded cross-section.

According to a further preferred embodiment of the heat exchanger according to the invention, the wing sections of the at least first and second wing tubes are arranged in flow direction next to each other and/or displaced with respect each other. Furthermore, and according to a further embodiment of the present invention, at least three or four serpentine-shaped wing tubes are used, the wing sections of which are arranged in at least one tube plane per wing tube, respectively.

For providing a compact and powerful heat exchanger, it is further preferred to arrange the wingless curved sections of the serpentine-shaped wing tube at a side of the serpentine-shaped wing tube, respectively, in a plurality of bending planes, which are parallel to each other and which extend in an angle with respect to the tube plane of the wing tube which corresponds to the angle of the wing plane related to the flow direction. This is especially advantageous, in case the serpentine-shaped wing tubes are according to a further preferred embodiment of the present invention integral, preferably extruded, wing tubes preferably from aluminum or aluminum alloy. Based on the above described shape of the wing tube consisting of wing sections and wingless curved sections it is then possible to insert the wingless curved sections in elongated holes in the sidewalls of the heat exchanger, which are provided therefore, and to retain them therein. Further fastening methods or couplings methods between the curved sections and the wing sections are thus at first not required in case the serpentine-shaped wing tubes are realized as integral wing tubes.

The present invention discloses further a serpentine-shaped wing tube for the above described heat exchanger for removing heat from a medium directed within the serpentine-shaped wing tube. This serpentine-shaped wing tube comprises the following features: a tube and at least two wings protruding radially therefrom, preferably oppositely, wherein the wing tube comprises at least three linear wing sections coupled via wingless curved tube sections, wherein the wing sections of the serpentine-shaped wing tube are arranged in at least one tube plane, wherein the wings of the wing sections are arranged in at least a plurality of first wing planes, which are arranged parallel to each other and which are arranged in a defined angle in the range of 10°≦α≦30° with respect to a normal of the first tube plane. The preferred constructive characteristics of the serpentine-shaped wing tube were already discussed above in combination with the preferred heat exchanger according to the invention.

The present invention discloses further a method for producing a serpentine-shaped wing tube, comprising the following steps: providing a linear wing tube consisting of a tube and at least two wings protruding radially therefrom, preferably oppositely, removing the wings in specific sub-sections so that linear wingless tube sections adjacent to wing sections occur, bending the wingless tube sections in a 180°-curve so that the wing-sections are arranged in one plane and the wings of the wing sections are orientated almost vertically to this plane, and twisting of U-shaped sections adjacent to each other which consist each of two adjacent wing sections coupled via a curved wingless tube section against each other so that at least a first wing section of the U-shaped section is arranged in a first tube plane and the wings of the wing sections are arranged in at least a plurality of wing planes, respectively, wherein the wing planes are arranged parallel to each other and in a defined angle in the range of 10°≦α≦30° with respect to a normal of the first tube plane.

According to the invention, the serpentine-shaped wing tubes forming the core of the heat exchanger are produced from a one piece wing tube. The linear wing sections, for example, are already present subsequent to the extrusion of the wing tubes from aluminum or an aluminum alloy according to a preferred embodiment of the present invention. The future curved wingless tube sections are created by removing the wings from the present wing tube. For providing a clear alignment and structured arrangement of the wing sections in the future heat exchanger, adjacent wing sections are always arranged in pairs in U-shaped sections. The sections arranged in pairs are coupled to each other via the wingless tube sections and the respective bending thereof For producing a serpentine-shaped tube having an alignment of the wings in a specific angle with respect to the future flow direction of the cooling medium, the U-shaped sections are twisted against each other out of a common plane of the serpentine-shaped wing tube such that the wings of the wing sections are arranged with respect to the later flow direction in an angle of 10°≦α≦30°. It is preferred to twist the U-shaped sections of the serpentine-shaped wing tubes against each other so that the adjacent wing sections of U-shaped sections are arranged in a first and a second tube plane. The wings of the wing sections of the first and the second tube plane are arranged in an angle range of 10°≦α≦30°, with respect to the normal of the tube plane or the flow direction of the future inflowing cooling medium. As this angle is always related to the smallest rotation angle between the wing and the normal of the tube plane or the flow direction, the wings may be arranged in a mathematical angle range of 10°≦α≦30°and −30°≦α≦−10° around the flow direction or the normal of the tube plane, which will be discussed in the following independently from the algebraic sign as angle in the range of 10°-30°. This understanding also applies to the remaining angles discussed in the following.

The present invention comprises further a method for producing the above-described heat exchanger comprising the following steps: providing a housing consisting of at least two opposite side walls having a plurality of elongated holes, preferably arranged parallel to each other, inserting at least one serpentine-shaped wing tube into the plurality of elongated holes of the opposite side walls such that a plurality of curved wingless tube sections is in engagement with the plurality of elongated holes, and coupling a coupling conduit to each of the open ends of the serpentine-shaped wing tube. According to a further preferred method step, two, three, four or more serpentine-shaped wing tubes are inserted into the plurality of elongated holes and the serpentine-shaped wing tubes are coupled to each other. Preferably, and in the production method, the wing tube is provided with recesses on the inner side of the tube and/or with curved wings as they were already explained above.

The present invention comprises further an air conditioner, a cooling device as well as a solar heat device having a heat exchanger as described above. A further application of the present invention is a dryer having a heat exchanger as described above. Preferably, in such a dryer, the heat exchanger is used in combination with a heat pump system. In the most general sense, the present invention is thus directed to the usage of the preferred heat exchanger according to the invention as condenser and/or evaporator in different devices.

4. SHORT DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The preferred embodiments of the present invention will now be described in detail with respect to the accompanying drawings. It shows:

FIG. 1 a perspective view of a preferred heat exchanger according to the invention,

FIG. 2 a side view of the heat exchanger of FIG. 1,

FIG. 3 a further preferred embodiment of the heat exchanger according to the invention,

FIG. 4 a side view of the heat exchanger of FIG. 3,

FIG. 5 an enlarged depiction of the encircled section of FIG. 4,

FIG. 6 a top view on a preferred embodiment of a serpentine-shaped wing tube,

FIG. 7 a side view of the serpentine-shaped wing tube of FIG. 6,

FIG. 8 an enlarged depiction of the encircled section of FIG. 7,

FIG. 9 a further preferred embodiment of a serpentine-shaped wing tube,

FIG. 10 a side view of the serpentine-shaped wing tube of FIG. 9,

FIG. 11 an enlarged depiction of the encircled portion of FIG. 10,

FIG. 12 a preferred embodiment of a serpentine-shaped wing tube having the wing sections in only one tube plane,

FIG. 13 a preferred embodiment of a serpentine-shaped wing tube having the wing sections in a first and in a second tube plane,

FIG. 14 installation sequences according to a preferred method for producing the heat exchanger,

FIG. 15 a preferred correlation between the energy releasing of the heat exchanger depending on the angle orientation of the wings of the serpentine-shaped wing tube,

FIG. 16 a preferred normalized energy removal of heat exchangers of different constructions depending on the angle of the wings with respect to the flow direction in case the arrangement of the wing sections is varied with respect to each other,

FIG. 17 an enlarged depiction of a preferred wing tube having wing sections and a wingless tube section,

FIG. 18 a flow chart of a preferred production method of a serpentine-shaped wing tube,

FIG. 19 a flow chart of a preferred production method of a heat exchanger,

FIG. 20 a cross-sectional view of a preferred embodiment of a wing tube according to the invention and

FIG. 21 a schematic cross-sectional view of a heat exchanger with preferred wing tubes having curved wings.

5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 and 3, preferred embodiments of the heat exchanger 1 according to the invention are shown. The heat exchanger 1 comprises a housing having at least two oppositely arranged sidewalls 10. Preferably, the housing comprises four sidewalls 10 arranged as a rectangle as well as a front plate 12 defining an inlet or outlet opening 14. Opposite to the inlet or outlet opening 14, the housing is open or it comprises a further opening (not shown). Based on this construction, air or any other cooling gaseous medium may be directed through the housing in a flow direction S (cf. FIG. 1). According to an embodiment, the sidewalls 10 consist of sheet metal with a painted or otherwise corrosion resistant coated surface. In this manner, the housing resists the thermal stresses and strains as well as the stresses and strains due to humidity. In case coated or painted sheet metals are used for producing the housing, they are preferably coupled to each other via clinching or riveting for avoiding a damaging of the sheet metal or the protective coating or surface finish thereon. It is certainly also preferred to produce the housing from plastic as long as the requirements with respect to stability and durability of the housing are fulfilled.

Usually, air is directed through the housing in flow direction S. To this end, the air is moved in flow direction S, for example sucked by means of a respective fan (not shown), which is preferably arranged at the backside of the heat exchanger 1. It is also conceivable to blow air through the heat exchanger 1 by means of the fan.

The heat exchanger 1 comprises a plurality of wing tubes 20 which are arranged within the housing of the heat exchanger. Preferably, the wing tubes 20 protrude transversely to the flow direction S and they are arranged in regular distances in a grid-like structure. FIG. 17 shows exemplarily a preferred embodiment of a wing tube 20 consisting of a tube 22 and wings 24 radially protruding therefrom. Preferably, the wings 24 are arranged oppositely to each other and they are formed linearly. It is also conceivable to arrange the wings 24 in a wavy or broken structure or to arrange more than two circumferentially distributed radial wings 24 at the tube 22.

According to a preferred embodiment, the wing tube 20 consists of extruded aluminum or an aluminum alloy. The wing tube 20 may also be produced in another way as by extrusion, as for example by rolling. Further, and for producing such wing tubes 20, all heat conductive materials are appropriate with which a wing tube 20 may be produced.

The wing tube 20 is hollow in the interior so that a medium, for example, liquids or gases may be directed through the wing tube 20. For example, in case air flows in flow direction S through the heat exchanger 1 and thus past the wing tube 20, heat is withdrawn from the medium directed within the wing tube 20 by means of the air flow and removed to the surrounding. The wings 24 of the wing tube 20 provide at this a larger surface so that the air flowing by may withdraw heat from the medium in the wing tube 20, provided that the air temperature is lower than the temperature of the medium in the wing tube 20 (cf. FIG. 17).

Preferably, the wing tube 20 is produced from aluminum, an aluminum alloy or any other heat-conductive material, preferably metal (cf. FIG. 18). According to a preferred embodiment for producing such wing tubes, the wing tube 20 is extruded (SI). According to an embodiment, the tube 22 has an outer diameter of about 8 mm and a wall thickness of about 0.7 mm. The wings 24 protrude in radial direction oppositely to each other for 7 mm, respectively. Thus, the wing tube 20 with wings 24 has an overall width of about 22 mm. According to a further preferred embodiment of the present invention, other than the above described materials and dimensions are used for producing the wing tube 20, provided that they correspond to the requirements for the heat exchanger 1.

For supporting the heat exchange between the surrounding and the medium within the wing tube 24, preferably the surface on the inner side of the tube of the wing tube 24 is increased. For this purpose, a plurality of recesses 25a is introduced in the inner side of the tube, which extend in radial direction according to a preferred embodiment shown in FIG. 20. Adjacent to the recesses 25a, preferably webs 25b protrude radially inwards into the interior of the wing tube 24. These webs 25b as well as the recesses 25a have preferably different cross-sectional shapes, which are determined for example by the production method or the size of the surface on the inner side of the tube which has to be achieved. Therefore, it is conceivable that the recesses 25a and/or the webs 25b are formed with a rectangular, triangular, polygonal or rounded cross-sectional design.

Once the wing tube 20 has been produced as a continuous part (SI), the wings 24 are removed in specific sub-sections in longitudinal direction of the wing tube 20. As a consequence, wing sections 30 and wingless tube sections 40 result, as it is shown in FIG. 17. As can be seen based on FIGS. 1 and 3, the wing sections 30 are arranged in the heat exchanger 1 substantially between the side-walls 10 and are flowed around in flow direction S. The wingless tube sections 40 are formed curved and are arranged in the section of the sidewalls 10 to retain the wing tube 20 within the housing of the heat exchanger 1.

Once the wing tube 20 has been produced and the wings 24 were removed in sub-sections, a linear wing tube 20 consisting of linear wing sections 30 and linear wingless tube sections 40 is present. Subsequently, the wingless tube sections 40 are bended by 180° so that a serpentine-shaped wing tube 20 is present. Within the serpentine-shaped wing tube, U-shaped sections 26 result having two wing sections 30 adjacent to each other, respectively, which are coupled to each other via a curved wingless tube section 40. The serpentine-shaped wing tube 20 is preferably bended (SIII) so that the wing section 30 is arranged in a common tube plane R1 and the wings 24 are orientated transversely to the tube plane R1.

Subsequently, U-shaped sections 26a, 26b, 26c adjacent to each other are twisted (SIV) such that a part of the tube sections 30 extending parallel to each other are arranged outside the tube plane R1 (cf. FIGS. 7, 8, 10, 11, 13). According to a preferred embodiment shown in FIG. 13, the U-shaped sections 26a, 26b, 26c are twisted around their longitudinally extending main axis such that the U-shaped sections 26a, 26b, 26c are arranged parallel to each other thereafter. In a preferred embodiment of this parallel arrangement of the U-shaped sections 26a-26c, one tube section 30 of a U-shaped section 26a is in tube plane R1 and the other tube section 30 of the U-shaped section 26a is in tube plane R2, respectively. It is also preferred to twist the U-shaped sections 26a-26c such that the tube sections 30 are arranged in further tube planes (not shown). Following the installation of the serpentine-shaped wing tube 20 in the housing of the heat exchanger 1, the tube planes R1 and R2 and thus the tube sections 30 are arranged preferably vertical to the flow direction S as can be seen for example in FIG. 1.

Preferably, at least one serpentine-shaped wing tube 20 is arranged in a heat exchanger 1. According to further preferred embodiments, three, four or more serpentine-shaped wing tubes 20a, 20b, 20c, 20d are installed in the housing of the heat exchanger 1, as can be seen in FIGS. 1, 2, 4, 14.

While the wing sections 30 extending transversely to the flow direction S are arranged between the side walls 10, the wingless curved tube sections 40 are arranged and retained in an elongated hole 16, respectively (cf. FIG. 2). The elongated holes 16 correspond to the size of the wingless curved tube sections 40 and the inclination thereof compared to one of the tube planes R1, R2. For retaining the at least one serpentine-shaped wing tube 20 in the heat exchanger 1, the wingless curved tube sections 40 are inserted and retained in both opposite sidewalls 10 in the elongated holes 16 provided therefore (SIV). As these sidewalls 10 are fixed in the heat exchanger 1 in a defined distance with respect to each other, the serpentine-shaped wing tubes 20 are not able to release itself from the elongated holes 16 and are thus permanently mounted in an easy manner.

As can be seen based on FIG. 4 depicting a cross-section along the line 4-4 in FIG. 3, four serpentine-shaped wing tubes 20 are installed in the heat exchanger 1. The wing sections 30 of each serpentine-shaped wing tube 20 are arranged in two tube planes R1, R2, respectively. Further, the wing sections 30 of different serpentine-shaped wing tubes 20, which are arranged adjacent in flow direction S, are arranged next to each other. It is also preferred to arrange the wing sections 30 displaced from each other to vary the flow around thereof (not shown).

Once the housing consisting of the at least two sidewalls 10 was provided (step H1), the serpentine-shaped wing tubes 20 are inserted in the elongated holes 16 in the sidewalls 10 (step H2). Subsequently, the sidewalls 10 are fastened to each other via at least one further housing wall, for example the front plate 12, or they are fastened on a base plate. In this way, it is ensured that the sidewalls 10 are fixed in a defined distance with respect to each other so that the serpentine-shaped wing tubes 20 may not drop out of the elongated holes 16 (cf. FIG. 14). Thereafter, adjacent serpentine-shaped wing tubes 20 are coupled to each other to provide one continuous flow path of the medium to be cooled through all serpentine-shaped wing tubes 20 which are fastened in the heat exchanger 1 (step H3) (cf. FIG. 19).

Subsequently, coupling conduits are coupled, preferably soldered, to the inlet and the outlet of the serpentine-shaped wing tubes 20 coupled to each other to be able to integrate the heat exchanger 1 into a cooling device, an air conditioner or a solar heat device (step H4). According to a preferred embodiment of the present invention, the heat exchanger 1 is provided with an own fan (not shown) by means of which for example cooling air can be directed over the wing sections 30, i.e. sucked or blown (cf. FIG. 8).

As can be seen from FIG. 12, the wings 24 are aligned vertically to the tube plane R1. Once the U-shaped sections 26a-26c have been twisted around the central longitudinal axis, the wings are arranged in a plurality of wing planes F. According to a preferred embodiment shown in FIGS. 6 to 8, the wings 24 of a serpentine-shaped wing tube 20 are arranged in a plurality of wing planes F1, which are arranged parallel to each other. The wing planes F1 and thus also the wings 24 enclose an angle α with the flow direction S according to FIG. 8, wherein FIG. 8 represents an enlarged depiction of the encircled portion of FIG. 7. Depending on the size of the angle α, a different large surface of the wing section 30 is flown past by the cooling medium. From an idealised point of view, the flown past surface varies depending on the cosine of the angle α, i.e. the flow past surface is at a minimum at an angle of α=0° and is at a maximum at an angle of α=90° with respect to the flow direction S.

FIGS. 9 to 11 show a further serpentine-shaped wing tube 20b arranged in the heat exchanger 1. Based on the twisting of the U-shaped sections 26 (see above) the wings 24 are arranged in the wing planes F2. It is preferred that the wing planes F2 of the serpentine-shaped wing tube 20b are arranged parallel to each other. According to a further preferred embodiment, the wings 24 are arranged in wing planes F which are not arranged parallel to each other.

As clarified by FIG. 11, the wing planes F2 and thus the wings 24 of the serpentine-shaped wing tube 20b enclose an angle β with the flow direction S. According to different preferred embodiments, the angle β is as large as the angle α of the adjacent serpentine-shaped wing tube 20a. It is also preferred to align the wings 20 of adjacent or in general of serpentine-shaped wing tubes 20a-20d inserted in the heat exchanger 1 in the same or in different angles to influence in this manner the flowing past the wing tubes 20 and thus especially the efficiency of the heat removal of the heat exchanger 1.

FIG. 15 shows a qualitative correlation between the pitch angle or setting angle α, β of the wings 24 related to the flow direction S and the heat W released from the heat exchanger 1. This correlation was determined with a heat exchanger 1 comprising four serpentine-shaped wing tubes 20. The wing sections 30 of different serpentine-shaped wing tubes 20a, 20b, 20c, 20d are preferably arranged behind one another in flow direction S (cf. FIG. 4). According to a further preferred embodiment, the closer adjacent wing sections 30 of different serpentine-shaped wing tubes 20a, 20b, 20c, 20d have a displacement of 2 mm vertical to the flow direction S with respect to each other similar to the arrangement in FIG. 4.

It can be seen that the heat removal starting at an angle of 10° increases continuously and reaches a maximum at 15°. For angles >15°, the heat removal decreases again until it reaches the value at around 18° corresponding to a pitch angle of 10° between wing 24 and flow direction S. Based on this correlation, it is preferred to arrange the wing 20 in an angle range of 10°≦α, β≦30°, further preferred 12°≦α, β≦18° and most preferred at an angle of α, β=15°.

According to a further preferred embodiment, the efficiency of the heat exchanger is also improved in that the wing tube has a plurality of wings 24′, as shown in FIG. 21. These wings 24′ extend also in radial direction to the outside. In contrast to the above described wing tubes, the wings 24′ are formed curved out of the wing planes F1, F2. Therefore, they have a cross-sectional design which is similar to the cross-section of an airplane wing. In this context, it is further preferred that the wings 24′ arranged opposite to each other are curved in different directions. This is also exemplarily shown in FIG. 21. According to a further preferred embodiment, the wings 24′ taper radially outwardly in their thickness. By means of this curved wing design, the heat removal between the surrounding and the medium within the wing tube is facilitated.

The efficiency of the heat removal of the heat exchanger may be further influenced by the arrangement of the wing sections 30 within the heat exchanger. According to a preferred embodiment, as also shown in FIG. 4, the wing sections 30 are arranged in flow direction S behind one another. According to a further embodiment of the present invention, the wing sections 30 of different serpentine-shaped wing tubes 20a, 20b, 20c, 20d are arranged vertically displaced with respect to each other and with respect to the flow direction S. With increasing displacement of the wing sections 30 of different serpentine-shaped wing tubes 20a, 20b, 20c, 20d to each other up to a central arrangement of a wing section 30 of a serpentine-shaped wing tube 20b with respect to two adjacent wing sections 30 of an adjacent serpentine-shaped wing tube 20a, 20c, the maximum heat removal of the heat exchanger 1 is shifted to larger angles α, β between the wing and the flow direction S (see above). This correlation is shown in FIG. 16. FIG. 16 shows as curve 1 a normed heat removal of a heat exchanger 1 having wing sections 30 arranged behind one another with respect to the flow direction S, as shown in FIG. 4. The curve 2 shows the normed heat removal for a heat exchanger 1, wherein the wing sections 30 of a serpentine-shaped wing tube 20b are arranged centrally displaced with respect to the wing sections 30 of adjacent serpentine-shaped wing tubes 20a, 20b. The arrow in FIG. 16 illustrates how the normed maximum of the heat removal is shifted with increasing displacement of the wing sections 30 with respect to each other up to the above described central arrangement maximally. As soon as the wing sections of a serpentine-shaped wing tube 20b are arranged eccentric with respect to the adjacent wing section 30 of an adjacent wing tube 20a, 20c, the normed maximum of the heat removal between the maximum of the curves 1 and 2 is realised.

Also, it can be concluded from FIGS. 8 and 11 that the wingless curved tube sections 40a, 40b are arranged in a bending plane B1, B2, respectively. The bending planes B1, B2 enclose with the adjacent tube planes R1, R2 the same angle as the respective wings 24 of the serpentine-shaped wing tube 20 with the flow direction S. As the elongated holes 16 in the sidewalls are adapted to the inclination of the wingless curved tube sections 40a, 40b, the elongated holes 16 are also inclined in this angle with respect to the line vertical to the flow direction S.

LIST OF REFERENCE SIGNS

• 1 heat exchanger
• 10 sidewall
• 11 front plate
• 14 opening
• 16 elongated hole
• 20 wing tube, serpentine-shaped wing tube
• 22 tube
• 24 wing
• 24′ curved wing
• 25a recess on the inner side of the tube
• 25b web on the inner side of the tube
• 26 U-shaped section
• 30 wing section
• 40 wingless tube section
• S flow direction
• W heat
• B1, B2 bending plane
• R1, R2 tube plane
• F1, F2 wing plane

Claims

1-34. (canceled)

35. Heat exchanger for removing heat from a medium, wherein the heat exchanger has the following features:

a. at least two outer walls defining an opening therebetween by means of which a gas flow is directable into a flow direction,

b. at least a first serpentine-shaped wing tube including a tube and at least two wings which protrude radially therefrom, wherein the wing tube has at least three linear wing sections coupled via wingless curved tube sections,

c. the wing sections of the at least first wing tube are arranged in at least one tube plane per wing tube, which is orientated vertically to the flow direction, wherein

d. the wings of the wing sections of at least the first wing tube are arranged in at least a plurality of first wing planes arranged parallel to each other, wherein the wing planes are arranged in a defined angle in the range of 10°≦α≦30° with respect to the flow direction.

36. Heat exchanger according to claim 35, comprising at least a second serpentine-shaped wing tube and the wing sections of the at least first and second serpentine-shaped wing tubes are arranged in two tube planes per wing tube such that adjacent wing sections of a wing tube are arranged in different tube planes.

37. Heat exchanger according to claim 36, wherein the wings of the wing sections of the second wing tube are arranged in at least a plurality of second wing planes arranged parallel to each other arranged, wherein the second wing planes are arranged in a second defined angle in the range of 10°≦β≦30° with respect to the flow direction.

38. Heat exchanger (1) according to claim 37, wherein the first or the first and the second defined angle lie in a range of 10°≦α, β≦20°.

39. Heat exchanger (1) according to claim 37, wherein the first or the first and the second defined angle lie in a range of 12°≦α, β≦18° or at an angle of 15°.

40. Heat exchanger (1) according to claim 36, wherein the wing sections of the at least first and second wing tubes are arranged in flow direction next to each other and/or displaced with respect to each other.

41. Heat exchanger according to claim 37, wherein the wing sections of the at least first and second wing tubes are arranged in flow direction next to each other and/or displaced with respect to each other.

42. Heat exchanger according to claim 36, comprising at least three or four serpentine-shaped wing tubes, the wing sections of which are arranged in at least one tube plane per wing tube, respectively.

43. Heat exchanger according to claim 37, comprising at least three or four serpentine-shaped wing tubes, the wing sections of which are arranged in at least one tube plane per wing tube, respectively.

44. Heat exchanger according to claim 36, wherein the wingless curved sections at a side of the serpentine-shaped wing tube, respectively, are arranged in a plurality of bending planes which are parallel to each other and which extend in an angle with respect to the tube plane of the wing tube which corresponds to the angle of the wing plane related to the flow direction.

45. Heat exchanger according to claim 37, wherein the wingless curved sections at a side of the serpentine-shaped wing tube, respectively, are arranged in a plurality of bending planes which are parallel to each other and which extend in an angle with respect to the tube plane of the wing tube which corresponds to the angle of the wing plane related to the flow direction.

46. Heat exchanger according to claim 35, wherein the serpentine-shaped wing tubes are integral wing tubes formed of an aluminum or an aluminum alloy.

47. Heat exchanger according to claim 35, the at least one serpentine-shaped wing tube of which is coupled only at its starting and end point to a further conduit or a further wing tube via a separate conduit.

48. Heat exchanger according to claim 36, the at least one serpentine-shaped wing tube of which has a plurality of recesses at an inner side of the tube which enlarge the surface of the inner side of the tube of the wing tube.

49. Heat exchanger according to claim 37, the at least one serpentine-shaped wing tube of which has a plurality of recesses at an inner side of the tube which enlarge the surface of the inner side of the tube of the wing tube.

50. Heat exchanger according to claim 48, wherein the recesses on the inner side extend in longitudinal direction of the wing tube and adjacent webs protrude radially into the interior of the wing tube.

51. Heat exchanger according to claim 49, wherein the recesses on the inner side extend in longitudinal direction of the wing tube and adjacent webs protrude radially into the interior of the wing tube.

52. Heat exchanger according to claim 35, wherein a plurality of wings are formed extending in radial direction and curved out of the wing planes.

53. Heat exchanger according to claim 47, wherein oppositely to each other arranged wings are curved radially outwardly in opposite directions.

54. Air conditioner having a heat exchanger according to claim 35.

55. Cooling device having a heat exchanger according to claim 35.

56. Solar heat device having a heat exchanger according to claim 35.

57. Dryer having a heat exchanger according to claim 35.

58. Usage of the heat exchanger according to claim 35 as condenser and/or evaporator.