DE102005028510A1 - Adjustable internal heat exchanger - Google Patents

Abstract

In a refrigerant circuit (10), it is proposed to use an internal heat exchanger (2) in which the thermal coupling between high pressure side (8) and low pressure side (9) of the internal heat exchanger (2) can be varied. If in an operating condition the temperature at the outlet of the compressor (4) threatens to become too high, the degree of exchange of the inner heat exchanger is reduced, so that the refrigerant flowing to the evaporator (4) is not additionally heated by the high-pressure side, originating refrigerant. This allows the compressor (4) to continue to operate at full power.

Description

The The invention relates to a heat exchanger for the heat transfer between at least two heat-storing Media. Furthermore, the invention relates to a heat exchanger assembly using such a heat exchanger and the use of the proposed heat exchanger or the proposed The heat exchanger assembly.

Heat exchanger be a very different in a variety of applications wide range of applications used.

For example find heat exchangers both in industrial processes, in motor vehicle construction, in the Air conditioning, in chemical processes and in energy production Application. As versatile as the applications allowed also the size of it used heat exchanger as well as the used, to be cooled or to be heated heat-storing Media.

The Commonality between such heat exchangers is that Thermal energy from a first heat storing Medium on a second heat-storing Transfer medium becomes. The first medium gives off heat, whereas the second Medium while heat receives. As a medium usually come in this context gaseous and liquid Materials, including a mixture of liquid and gaseous Substances may be present. Possible it goes without saying also that at least one of the two media, for example, solids in Form of a suspension with it. Possible It is also that one or both of the media used in the course the heat transfer (partially) changes its state of aggregation, so for example a liquid (partially) evaporated or a gas (partially) condensed. By the way it is also conceivable that in a heat exchanger more when two media are in thermal contact with each other.

at Heat Bert Ragern In the prior art, efforts have been made so far, the heat transfer between the heat transfer process inlaid media as far as possible to increase. This was done especially with regard to a reduction of the Size of the heat exchanger, the for transmission a certain heat output is required to reduce the use of materials and thus in terms of the cost of the heat exchanger and to reduce the weight of the heat exchanger for a particular task. Purely by way of example has been lately in heat exchangers for automotive engineering an internal contouring of pipes through which heat-storing medium flows proposed with longitudinal ribs or protrusions in the form of so-called "winglets" were provided.

In In every case, according to the prior art, there has hitherto been a desire in the presence of certain parameters (such as to be used Materials for the heat exchanger, production costs, Maintenance, durability, used heat-storing media, space requirements etc.) the heat transfer performance between the heat-storing Media as much as possible to enlarge.

So far in individual cases there was a requirement, the heat release from or the Wämeaufnahme in a heat-storing To reduce medium, so far this has been through a reduction the flow rate of the corresponding heat-storing medium dissolved. This Approach was, for example, the so-called short-circuited heating circuit selected bypassing the coolant radiator or also with air conditioners for Motor vehicles selected, wherein to reduce the cooling capacity the compressor is switched off temporarily or the displacement of the Compressor is reduced and so less refrigerant in the refrigerant circuit is moved.

Surprisingly, however, it has now been found that this procedure - ie providing as high as possible maximum heat transfer performance and possibly reducing the flow of heat-storing medium through the heat exchanger - may prove to be disadvantageous in certain applications. The inventors have therefore made it their task to propose a heat exchanger or a heat exchanger arrangement which at least partially eliminates or at least reduces the inherent disadvantages of systems according to the prior art. In particular, the inventors have made it their task to propose a heat exchanger, in which the heat output from the or the heat supply can be reduced in the corresponding heat-storing medium, without the flow rate of the heat storage medium through the heat exchanger or the heat exchanger assembly must be reduced , In addition, the proposed heat exchanger or the proposed heat exchanger assembly should be particularly simple, inexpensive and space-saving, have a clotting ges weight and be as durable, durable and maintenance-insensitive or easy to maintain. Continue to have it The inventors set themselves the task to propose a particularly advantageous use for such heat exchangers or such heat exchanger arrangements.

Of the in the independent ones claims proposed heat exchanger or the heat exchanger arrangement proposed there and their use triggers This task.

So it is proposed to use a heat exchanger for the heat transfer between at least two heat-storing To further develop media in such a way that it has a variable heat transfer interface has, by means of which the heat transfer rate between at least two of the media passed through the heat exchanger can be varied. Of course, the heat transfer interface be constructed in such a way that with her - in the presence of, for example three or more media - the Heat transfer level between each two of these media preferably individually and selectively changed can be. However, there is also a shift, for example a quotient of two heat transfer lines to think. Anyway, it's thanks to the proposed training of the heat exchanger possible, that, for example, in the case of two heat-storing media, between which cause a heat transfer comes, one of the media or both media with the same Mass flow rate of the heat exchanger can flow through, and it still possible is, the heat transfer between the two media depending on the respective operating state the heat exchanger changing system to change. In the already mentioned above Case of a coolant-cooled engine could thus the coolant cooler with the usual Coolant flow rate be charged, it - for example during the warm-up phase of the engine - still possible that the heat dissipation from the coolant is reduced. This can reduce the heating time of the engine although a separate shorted refrigerant circuit, which corresponding branch points and components, in particular a thermostatic valve is needed, can be waived. Such a structure may prove to be less expensive, space-saving, durable or less sensitive to interference.

A possible Formation of the variable heat transfer interface arises when the variable heat transfer interface comprising a variable material introduction device. So it would be possible for that interspersed between two of the respective heat-storing media heat exchanger tubes a thermally insulating Material is introduced or to be removed or even a thermally conductive Material is introduced or removed. Also a combination of these both ways is conceivable. In the introduced or to be removed material it can be a solid act or even to a suitable medium, in particular to a suitable fluid, for example, in a between each two of the corresponding heat storing Media interspersed heat exchanger tubes arranged pipe can be introduced, with the appropriate Medium filled or can be emptied from this. In the case of liquids For example, the degree of heat transfer by a corresponding degree of filling be varied. In the case of insulating or heat-transferring gases can be a variable heat transfer rate realized for example by a corresponding pressurization become. For solids, the variable heat transfer coefficient by a corresponding wide insertion or removal of the appropriate material will be realized.

Is possible It also, that the variable heat transfer interface has at least one adjustable fluid supply device. Here is the variation of the degree of heat transfer between the respective heat-storing Media can be achieved by an external to the heat exchanger tubes over run Fluid (for example, a gas, in particular ambient air) a first heat-storing Medium, which heat to a second heat-storing Medium transfers, heat energy deprives, so that this heat energy no longer for transmission from the first to the second heat-storing Medium available stands. Here, for example, by a corresponding throughput of fluid through the fluid supply device a variation of the heat transfer between first and second heat-storing Medium can be achieved.

A especially cheap Construction results when the adjustable fluid supply device at least partially as a flap blind and / or as a roller blind is trained. Such components are known per se and become for others Tasks often used. They are relatively inexpensive and available usually a state of development, the cost-effective, low-maintenance use allows.

A suitable tube configuration, in particular for the heat exchanger tubes, results if the heat exchanger has at least one coaxially formed pipe section. As a result, for example, two heat-storing media can be guided in particularly intimate thermal contact with each other, while still leaving the possibility to bring a third medium in good thermal contact with at least one of the two heat-storing media. This can be a be particularly compact design of the heat exchanger can be realized with a large maximum heat transfer rate.

A In practice, preferable construction results when the heat exchanger as a flat tube heat exchanger stacked on top of each other, is formed parallel to each other extending flat tubes. With such an embodiment can at a relatively low cost of materials and space requirements very good maximum heat transfer between the heat-storing Media be realized. Of course it is also with flat tubes possible, to realize a coaxial structure.

Particularly in the case where one or more heat-storing media are under high pressure, it proves to be advantageous if at least one pipe section of the heat exchanger has a plurality of flow channels for at least one of the media passed through the heat exchanger. For example, if the proposed embodiment is implemented in the form of so-called "microchannels", pressures in the range of 100, 120, 130, 133, 135, 140, 150, 180 or 200 bar (to name a few numerical values, as in the case of CO ₂ -driven air conditioning systems can occur, or how they must be able to control for safety reasons) are quite easily controlled with reasonable cost of materials and using conventional, relatively inexpensive materials.

Is possible it, the heat exchanger such that at least one tube is formed in one piece is, at least one pipe formed in several pieces or a combination of these is present. Here can be a good compromise from simple manufacturability, particularly good strength and durability, Pressure tightness, manufacturing cost, material workability, etc. being found.

Is possible it that for different media provided pipe flow ranges a different Have length. This can be made possible in a particularly simple manner, the different Media at the ends of the respective heat exchanger tubes from each other separately added or removed.

This can be done, for example, that the pipe flow areas lead into headers. This makes it possible, in particular, for a plurality of heat exchanger tubes for the heat-storing Media can be connected in parallel, so that, for example an elevated one Throughput of the corresponding media, an increased maximum heat transfer capacity or a use of particularly viscous heat-storing media is possible.

A conceivable design arises when at least a portion of the heat exchanger tubes at least partially directly superimposed. Here, for example, a particularly compact structure and a particularly high maximum heat transfer capacity will be realized.

Conceivable However, it is also that at least part of the heat exchanger tubes at least partially spaced from each other is arranged. One Such distance can, for example, for the introduction of heat-insulating or heat-transferring Materials used or used for tubular cavities Be that with heat-insulating or heat transferring Fluids are filled can.

Especially if the variable heat transfer interface an adjustable gas supply device It also makes sense when between at least one part the heat exchanger tubes Corrugated ribs are arranged. By such corrugated fins, the interface surface to flow through Fluid (for example, cooling air) can be increased.

Of course it is it also possible a direct arrangement, a spaced arrangement or intermediate Corrugated ribs combine with each other, for example by a Pipe sequence: first heat transferring Medium - second heat transferring Medium - first heat-transfer Medium - cavity - second heat-transfer Medium - corrugated rib - first heat-transfer Medium - etc. chosen from the beginning becomes.

By a three-dimensional arrangement of heat exchanger tubes can be in particular space advantages result. In this case, for example heat exchanger tubes not just relocated in a plane, but it is superimposed realized a three-dimensional structure of two such pipe planes, which is usually a as a "double row" designated heat exchanger results.

Especially for cost and weight reasons has proved to be advantageous if the proposed heat exchanger at least partially made of aluminum and / or an aluminum alloy is made.

A particularly cost-effective production may also arise in particular if at least parts, such as in particular heat exchanger tubes and / or manifolds of the heat exchanger manufactured by means of an extrusion process are. With such a manufacturing method, for example, heat exchanger tubes provided with so-called "microchannels" can be manufactured in a particularly simple and cost-effective manner.

Especially It is also advantageous if the heat exchanger as an internal heat exchanger for one Refrigerant circulation is trained. It has been shown that a heat exchanger with the proposed Training for this application is particularly advantageous. This is especially true when using carbon dioxide as refrigerant for the refrigerant circuit.

Farther becomes a heat exchanger arrangement proposed in which at least one heat exchanger with the previously described construction, if necessary including their variations, and one or more other heat exchangers. With others In words, this may result in a kind of heat exchanger module in which the heat exchanger module a heat exchanger having the previously proposed construction and the other parts are designed as further, other tasks perceiving heat exchanger. Such a training as a multifunctional module can especially with regard to space requirements, but also with regard to to prove advantageous to the assembly.

at the other heat exchangers the heat exchanger assembly These may be, for example, gas coolers, condensers, coolant coolers, oil coolers, intercoolers, exhaust gas coolers and / or evaporators act. Such heat exchangers are at a big one Part of currently produced motor vehicles usually available.

A to be preferred development results when in the heat exchanger assembly at least one collecting pipe for the heat exchanger and at least one collecting pipe for another heat exchanger as a continuous Collecting tube, in particular as fluidic continuous collecting pipe is trained.

One mechanically continuous, However, if necessary, fluidic Separate manifold can, for example, in terms of stability and manufacturing costs the heat exchanger assembly as cheap prove. The fluidic Separation can, for example, by a soldered or welded disc be realized. In contrast, however, the manifold can also fluidically continuously accomplished be, which is particularly advantageous if the corresponding Medium anyway has to flow through different heat exchangers in a row, as for example with a gas cooler with a downstream one internal heat exchanger (IWT) is the case. Thereby can For example, connections of refrigerant pipes and components can be saved, which is especially at high pressure Fluids, such as in the case of carbon dioxide, an advantage can be.

at the proposed heat exchanger assembly Is it possible, that heat exchanger tubes at least two different heat exchangers at least partially spaced from each other are arranged. This allows a particularly good thermodynamic separation of the corresponding Heat transfer heritage rich the heat exchanger assembly will be realized.

Is possible However, it is also that in the heat exchanger assembly heat exchanger tubes at least two different heat exchanger at least partially are formed directly adjacent to each other. This may possibly be a Simplification in the manufacture of the heat exchanger assembly with it bring. Although it is conceivable that by the mechanical Contact accompanying thermal coupling an undesirable in itself Heat transfer occurs, but this can be an order of magnitude, for example in which the effects occurring in relation to other benefits are of lesser importance.

It is by the way also possible, despite a mechanical coupling of two heat exchangers of the heat exchanger assembly to achieve at least partial thermal decoupling, for example by at least partially between the heat exchanger tubes of different heat exchangers a corrugated fin is arranged.

Also it is conceivable that thermal insulation means, in particular between the heat exchanger tubes different heat exchanger provided become. With thermal insulation means in this sense it can are not just about insulating materials, but also, for example to suitable thermal insulation recesses, so that, for example by a corresponding removal of material (eg also in the corrugated ribs can be provided) a thermal decoupling is realized.

A particularly advantageous use of the heat exchanger described above or the previously described heat exchanger assembly arises when this as an internal heat exchanger for a preferably used with carbon dioxide-operated refrigerant circuit become.

Other features, tasks, benefits and possible embodiments of the invention will become apparent from the accompanying drawings and the following description of preferred embodiments of the invention.

It demonstrate:

1 : A block diagram of a refrigerant circuit with a heat exchanger assembly according to a first embodiment of the invention;

2 : A schematic structure of a heat exchanger module according to the first embodiment of the invention;

3 : An inner heat exchanger according to the first embodiment of the invention;

4 : A flat tube for an internal heat exchanger in a schematic view;

5 : A flat tube for an internal heat exchanger in cross section;

6 : A part of a flat tube of an internal heat exchanger in a side plan view;

7 : A schematic top view of the in 3 shown inner heat exchanger from below;

8th : An inner heat exchanger according to a second embodiment of the invention;

9 A heat exchanger module in schematic view according to a third embodiment of the invention;

10 A heat exchanger module in schematic view according to a fourth embodiment of the invention;

11 A heat exchanger module in schematic view according to a fifth embodiment of the invention;

12 : A variable heat transfer heat exchanger according to a sixth embodiment of the invention;

13 : A heat exchanger with variable heat transfer rate according to a seventh embodiment of the invention.

In 1 is a block diagram of a refrigerant circuit 10 represented, the present R744 or carbon dioxide used as a refrigerant.

The refrigerant circuit 10 has in a conventional manner a compressor 4 , a gas cooler 3 (As a carbon dioxide refrigeration cycle is usually operated supercritically, is of a gas cooler 3 instead of speaking of a condenser), the high pressure part 8th an internal heat exchanger (IWT) 2 , an expansion organ 6 , an evaporator 5 , a cold medium accumulator 1 and the low pressure part 9 of the internal heat exchanger 2 on, which are flowed through during operation of the air conditioner in this order of the refrigerant. In the present embodiment shown are the gas cooler 3 and the inner heat exchanger 2 Part of a heat exchanger assembly described in more detail below 7 , which in addition to further, in 1 for illustration technical reasons, not shown heat exchanger has.

The inner heat exchanger 2 is, according to the invention, designed as a heat exchanger with a variable heat transfer rate.

In refrigerant circuits which use carbon dioxide as a refrigerant, it can under certain operating conditions, eg. B. in the case of a high pressure ratio between the high pressure side 8th and low pressure side 9 Shortly after switching on the air conditioner or at very high ambient temperatures, it may happen that the refrigerant is due to the compression in the compressor 4 on the output side of the compressor 4 has a very high temperature that is above a maximum permissible refrigerant temperature (hot gas temperature). In such a case, according to the prior art, the compressor power 4 reduced so that the hot gas temperature does not exceed the maximum allowable value. Although this method ensures compliance with the temperature limits, this is done at the expense of the refrigeration capacity of the air conditioner. Such a reduction of the cooling capacity is undesirable, especially at high outside temperatures or shortly after switching on the air conditioning system, since a comfortable interior temperature in the motor vehicle can not or can only be achieved significantly later.

The inventors have now recognized that it is also possible to control the inlet temperature of the refrigerant at the inlet to the compressor 4 which also decreases the hot gas temperature of the refrigerant after the compressor 4 entails. The easiest way initially would be to install an internal heat exchanger 2 to renounce. In particular, in the case of carbon dioxide as a refrigerant, however, this would result in a deterioration of the cooling capacity and a deterioration of the efficiency of the refrigerant circuit result. Therefore, the inventors propose an internal heat exchanger 2 before, in which the degree of exchange between the low-pressure side refrigerant 9 (Refrigerant) from the accumulator 1 to the compressor 4 flows) and high-pressure side refrigerant 8th (Refrigerant, which from the gas cooler 3 to the expansion valve 6 flows) can be varied. In the case of normal operating conditions, the exchange rate is large, so that the gas cooler 3 coming refrigerant in the inner heat exchanger 2 can be pre-cooled and only then to the expansion organ 6 flows where it is further cooled during the expansion and thereby liquefied. To cool the high-pressure side refrigerant is from the accumulator 1 to the compressor flowing low-pressure side refrigerant used, which among other things also has the advantage that a "wet" of the compressor 4 can be effectively prevented (ie, a suction of liquid refrigerant, causing damage to the compressor 4 could lead).

However, there are operating conditions in which at the maximum compression capacity of the compressor 4 an unacceptably high hot gas temperature occurred, so first the degree of heat exchange between niederdruckseitigem 9 and high-pressure side 8th Part of the internal heat exchanger 2 reduced. As a result, the high-pressure side heats up 8th Refrigerant to the compressor 2 flowing low pressure side 9 Refrigerant is not added in addition, so that the low-pressure side 9 Refrigerant at the compressor inlet has a lower temperature and as a result, the hot gas temperature is lower. If the reduction in the degree of heat exchange of the internal heat exchanger is still insufficient to keep the hot gas temperature within acceptable limits, it is of course possible to additionally reduce the compressor output. To carry out this control method, it is possible in particular to use an electronic control system of the air conditioning system, which is generally present anyway. As soon as the situation in the further operation of the air conditioner "normalized" again, first the compressor power is increased again to the full value and then brought the degree of exchange of the inner heat exchanger to higher heat exchange degrees. This is of course not contrary to the fact that in cases where there is indeed a very high hot gas temperature, on the other hand, however, the interior temperature of the motor vehicle is already sufficiently low, and initially the compressor power of the compressor 2 can be lowered.

In 2 is the schematic structure of in 1 used heat exchanger assembly 7 outlined. The heat exchanger arrangement is characterized by an air flow in 2 indicated by arrows A, acted upon by external cooling air. Should in the context of certain driving conditions of the with the heat exchanger assembly 7 For example, if the vehicle is equipped with an increased supply of external cooling air (eg at high outside temperatures in traffic jams or in slow uphill driving with high towing loads), one can enter the heat exchanger arrangement 7 integrated fan 13 be switched to the air flow rate A through the heat exchanger module 7 to increase.

The heat exchanger module 7 points at in 2 illustrated embodiment, an inner heat exchanger 2 , a gas cooler 3 , a charge air cooler 11 and a coolant cooler 12 on. gas cooler 3 and inner heat exchanger 2 are arranged in a plane and are supplied in parallel with cooling air A. Behind the level of inner heat exchanger 2 and gas cooler 3 are - in series and in order - the intercooler 11 , the intercooler 12 and the (suction) fan 13 ,

In the air supply shaft 17 for the inner heat exchanger 2 is a present as a folding blind 16 trained adjustable air supply device. However, other variants are possible, such as a roller blind. The folding blind 16 (or another design) can also adjacent to the inner heat exchanger 2 or also with respect to the air flow A behind the inner heat exchanger 2 be arranged.

Possible designs of the internal heat exchanger 2 are shown in more detail below.

In 3 is a first possible embodiment of an internal heat exchanger 2 with variable heat exchange degree between high pressure side 8th and low pressure side 9 Refrigerant shown. The inner heat exchanger 2 is a flat tube heat exchanger with a plurality of flat tubes arranged one above the other 20 shown. Between the flat tubes 20 are corrugated ribs 25 arranged, which increase the heat transfer to the possibly passing through outside air A. The flat tubes 20 are, as in 4 and 5 shown as coaxial flat tubes 20 educated. The flat tubes are in an extrusion process with a variety of microchannels 15 educated. The internal microchannels 15 lie in the high-pressure side 8th part 28 of the refrigerant circuit 10 , Accordingly, the external microchannels lie 15 in the low pressure side 9 part 29 of the refrigerant circuit.

Like that 4 and 6 can be taken, is the high pressure side part 28 the flat tubes 20 in relation to the low-pressure side part 29 the flat tubes 20 extended executed. In 6 is only one end page 30 of the flat tube 20 shown; usually concerns the extended version 30 of the high pressure side part 28 of the flat tube 20 both sides 30 of the flat tube 20 ,

In the 4 and 6 recognizable high-pressure side 8th tubular projections 30 can be formed, for example, that the flat tube 20 is extruded in one piece and the corresponding side area 30 of the flat tube by a chipping processing on the high-pressure side inner part 28 is rejuvenated. It is also possible that the high pressure side inner part 28 of the flat tube 20 and the low-pressure side outer part 29 of the flat tube 20 each extruded separately and then plugged into each other (multi-piece construction). Depending on the requirement, both types of construction can be considered more favorable for the respective purpose.

As in 3 as well as in plan view from below in 7 can be seen well, opens the low-pressure side outer part 29 of the flat tube 20 in a presently designed as a round tube low-pressure side manifold 21 of the internal heat exchanger 2 , The high pressure side 8th interior 28 the flat tube, on the other hand, extends through its side area 30 the low-pressure side manifold 21 completely and flows into the high pressure side manifold 18 , which in the present case is also designed as a round tube.

Even if this is in 3 is not shown in detail, it is possible that one of the high pressure side manifolds 18 fluidically with a manifold of the gas cooler 3 communicates. However, it is also possible that the headers 18 of the internal heat exchanger 2 fluidically completely from the manifolds of the gas cooler 3 are separated, for example by introducing a cutting disc.

Depending on the construction, suitable for reasons of clarity in 3 not shown connecting flanges for the high pressure side part of the inner heat exchanger 2 provided.

In 3 are connecting flanges 22 . 23 outlined as an inlet 26 and outlet 27 for the low pressure level 9 used refrigerants serve. The in 3 illustrated inner heat exchanger 2 is designed as a so-called "single-entry" heat exchanger, that is, that through the connection flange 22 fed, at low pressure level 9 located refrigerant the respective outdoor areas 29 the flat tubes 20 in the same direction of flow B passes through and then the connection flange 23 from the inner heat exchanger 2 exit 27 , It should be noted that the flow direction of the refrigerant B only on the low-pressure side 9 part 29 refers. The high pressure side 8th In contrast, refrigerant can in the same or opposite direction through the interior 28 the flat tubes 20 stream.

In 8th is still one of 3 deviating low-pressure side flow rate in the form of a so-called "double-flow" heat exchanger outlined. That over the connecting flange 21 entering 26 Refrigerant is through a in one of the two low-pressure side manifolds 21 located partition 22 through the in 8th low-lying flat tube 20 directed. After another distraction in the 8th right low pressure side manifold 21 it flows in the opposite direction through the two in 8th overhead flat tubes 20 back to in 8th on the left-hand side low-pressure manifold 21 where it finally reaches the connecting flange 23 exit 27 , Again, the flow direction in the high pressure side 8th inner part 28 the flat tubes 20 independent of the respective flow direction in the low-pressure side 8th outdoors 28 the flat tubes 20 ,

Incidentally, it is of course also possible that, deviating from the in 3 and 8th illustrated embodiments of the inner heat exchanger 2 , the connecting flanges 22 . 23 (as well as the in 3 and 8th not shown high-pressure side connecting flanges) also elsewhere, such as in a cover area of the headers 21 . 18 , can be trained.

In the 9 to 11 are exemplary further possible combinations for a heat exchanger module 7 with an internal heat exchanger 2 shown.

In 9 is the inner heat exchanger 2 in a lower area of the gas cooler 3 educated. The gas cooler 3 is at the 9 sketched construction of the heat exchanger module 7 constructed as a double-row flat tube gas cooler. Im in 9 However, the lower area is one of the two rows of flat tube gas cooler 3 as an internal heat exchanger 2 , This structure may be particularly advantageous in particularly cramped space conditions.

Furthermore, it is possible to use the inner heat exchanger 2 outside the supply air flow A, as in 10 is indicated. The inner heat exchanger can shear modulus in any way as part of the Wärmetau 7 integrally formed (as in 10 indicated) or else from the heat exchanger module 7 be formed separately.

In 11 Finally, a construction is shown, in which the inner heat exchanger 2 integral in the heat exchanger module 7 is formed and aligned with parts of the intercooler 11 and coolant cooler 12 in one level with the gas cooler 3 is trained. The inner heat exchanger 2 is however with the help of an air partition 14 fluidically removed substantially from the outside air stream A.

Especially for those in the 10 and 11 illustrated heat exchanger modules 7 used inner heat exchanger 2 are heat exchangers with variable heat transfer rate, in which the variation of the heat transfer rate takes place without an exposure of the heat exchanger with this passing outside air, advantage. Conceivable embodiments of such heat exchangers are in the 12 and 13 outlined.

When in 12 sketched heat exchanger 34 with variable heat transfer rate are first medium lines 31 for a first heat-storing medium (eg medium to be cooled), which is used as a flat tube 20 with a variety of microchannels 15 are formed. Furthermore, similarly trained second medium lines 32 provided, through which a second heat-storing medium (eg, medium to be heated) flows. First medium lines 31 and second medium lines 32 are alternately stacked on top of each other. It is between first medium lines 31 and second medium lines 32 one coupling tube each 33 arranged. The coupling tube 33 has a cavity 35 on, which can be filled with an insulating or thermally conductive fluid, or emptied again. Depending on the degree of filling (eg liquid level in the case of a liquid or gas pressure in the case of a gas), the heat transfer between each is via the coupling tube 33 thermally contacted to each other first medium lines 31 and second medium lines 32 different sizes, resulting in the desired variability of the heat transfer between the first and second medium.

In 13 is sketched another training option of a heat exchanger with variable heat transfer. Here are each triple stack 36 from first medium lines 31 and second medium lines 32 educated. In a first version 36a the triple stack 36 there is a second medium line 32 in the middle and is (covered on its flat sides) of two first medium lines 31 , Accordingly, in the second version 36b the triple stack 36 the first medium line 31 arranged in the middle and their flat outer sides are of second medium lines 32 covered. The two versions 36a . 36b alternate each other, each between two triads 36 a coupling tube 33 of the type already described is provided.

In the 12 and 13 shown pipes can be connected to each other, for example by soldering. Incidentally, the cavities 35 the coupling pipes 33 through in 12 and 13 for clarity reasons, filling openings, not shown, can be filled or emptied. Instead of the coupling tubes 33 It is also conceivable that corresponding recesses are provided in the example, control slide can be inserted.

In particular, the in 12 and 13 shown heat exchanger 34 are also suitable for other heat exchanger applications than for use as an internal heat exchanger in refrigerant circuits.

Claims (26)

Heat exchanger for the Heat transfer between at least two heat-storing Media characterized by a variable heat transfer interface by means of derer the degree of heat transfer between at least two of the media passed through the heat exchanger can be varied. Heat exchanger according to claim 1, characterized in that the variable heat transfer interface has at least one variable material introduction device. Heat exchanger according to claim 1 or 2, characterized in that the variable Heat transfer interface has at least one adjustable fluid supply device. Heat exchanger according to one of the preceding claims, characterized that the adjustable fluid supply device at least partially as a flap blind and / or as a roller blind is trained. Heat exchanger according to one of the preceding claims, which comprises at least one Having coaxially formed pipe section. Heat exchanger according to one of the preceding claims, characterized that the heat exchanger as a flat tube heat exchanger with stacked on top of each other arranged, parallel to each other flat tubes is formed. Heat exchanger according to one of the preceding claims, characterized that at least one pipe section of the heat exchanger to a plurality of Flow channels for at least one through the heat exchanger guided through Media has. Heat exchanger according to one of the preceding claims, characterized in that at least one tube is integrally formed. Heat exchanger according to one of the preceding claims, characterized that at least one tube is multi-piece is trained. Heat exchanger according to one of the preceding claims, characterized that for different media provided pipe flow areas a different length exhibit. Heat exchanger according to one of the preceding claims, characterized that the pipe flow areas open into headers. Heat exchanger according to one of the preceding claims, characterized that heat exchanger tubes at least partially directly superimposed. Heat exchanger according to one of the preceding claims, characterized that heat exchanger tubes at least partially spaced from each other are arranged. Heat exchanger according to claim 13, characterized by between heat exchanger tubes arranged corrugated ribs. Heat exchanger according to one of the preceding claims, characterized by a three-dimensional arrangement of heat exchanger tubes. Heat exchanger according to one of the preceding claims, which at least partially made of aluminum and / or an aluminum alloy. Heat exchanger according to one of the preceding claims, in which at least parts, in particular heat exchanger tubes and / or manifolds are made by means of an extrusion process. Heat exchanger according to one of the preceding claims, which is designed as an internal heat exchanger is. The heat exchanger assembly, which at least one heat exchanger according to one of the claims 1 to 18 and at least one further heat exchanger. The heat exchanger assembly according to claim 19, in which at least one of the further heat exchangers a gas cooler, a condenser, a coolant radiator, an oil cooler Intercooler, an exhaust gas cooler and / or an evaporator. The heat exchanger assembly according to claim 19 or 20, wherein the at least one collecting tube for the heat exchanger and at least one collecting pipe for another heat exchanger as a continuous Collecting tube, in particular as fluidic consistent Collector is formed. The heat exchanger assembly according to one of the claims 19 to 21, characterized in that heat exchanger tubes at least two different heat exchanger at least partially spaced from each other are arranged. The heat exchanger assembly according to one of the claims 19 to 22, characterized in that heat exchanger tubes at least two different heat exchanger are at least partially formed directly adjacent to each other. The heat exchanger assembly according to claim 23, characterized by an at least partially between the heat exchanger tubes different heat exchanger arranged corrugated rib. The heat exchanger assembly according to one of the claims 18 to 24, characterized by thermal insulation means, in particular by thermal insulation recesses. Use of a heat exchanger according to one of claims 1 to 18 and / or a heat exchanger assembly according to one of claims 19 up to 25 as internal heat exchanger for one Refrigerant circulation, especially for a refrigerant circuit operated with carbon dioxide.