WO2011003444A1

WO2011003444A1 - Heat exchange system and method for operating a heat exchange system

Info

Publication number: WO2011003444A1
Application number: PCT/EP2009/058632
Authority: WO
Inventors: Holger König; Franz Summerer.
Original assignee: A-Heat Allied Heat Exchange Technology Ag
Priority date: 2009-07-07
Filing date: 2009-07-07
Publication date: 2011-01-13
Also published as: CA2767378A1; EP2452148A1; AU2009349362A1; MX2012000210A; CN102472602A; US20120199310A1; JP2012532306A; RU2012104027A

Abstract

The invention relates to a heat exchange system (1), comprising a heat exchanger (2) having a flow channel (210) arranged in a flow segment (21). In order to exchange heat between a transport fluid (3) and a heating means (4) that flows through the flow channel (210) in the operating state, the transport fluid (3) can be brought into flow contact with the heat exchanger (2) by means of an inflow area (201) and led away from the heat exchanger (2) by means of an outflow area (202). According to the invention, a soiling sensor (5) in the form of a pressure sensor (5) and/or a speed sensor (5) is provided in order to determine a degree of soiling (V) of the heat exchanger (2), by means of which soiling sensor a transport parameter (TK) that is characteristic of the flow of the transport fluid (3) from the inflow surface (201) across the outflow surface (202) can be determined. The invention further relates to a method for operating a heat exchange system (1).

Description

Heat exchange system, and a method for operating a

The invention relates to a heat exchange system and a method for operating and determining a degree of soiling of a

Heat exchange system according to the preamble of independent claims 1 and 11.

The use of heat exchange systems is in a barely too

survey of the number of applications known in the art. Heat exchangers are used in refrigerators, e.g. in ordinary

Household refrigerators used in air conditioners for buildings or vehicles of all kinds, especially in automobiles, aircraft and ships, as water or oil coolers in internal combustion engines, as condensers or evaporators in refrigerant circuits, such as in heat pumps and in countless other applications, the the skilled person are all well known. There are different ways to classify heat exchangers from different applications. One attempt is to make a distinction according to the design of the various types of heat exchangers. Thus, on the one hand, a classification according to so-called "laminated

Heat exchangers ", which may also be referred to as" tube heat exchangers ", and on the other hand to" Minnichannel ",

Microchannel heat exchangers or microchannel heat exchangers

be made. The laminated tube heat exchangers, well known for a very long time, serve, like all types of heat exchangers, to transfer heat between two media, eg, but not only, to transfer from a cooling medium to air or vice versa, as is known, for example, from a classic household refrigerator in which over the

Heat exchanger for generating a cooling capacity inside the

Refrigerator is given off heat to the ambient air.

The ambient medium outside of the heat exchanger, eg water, oil or often simply the ambient air, for example, absorbs the heat or is transferred from the heat to the heat exchanger is either cooled or heated accordingly. The second medium may be, for example, a liquid refrigerant or heat transfer medium or an evaporating or condensing heat medium. For the purposes of this application, the term "heating means" is to be understood as meaning any fluid which can be advantageously used in a heat exchanger. The term "heating means" thus encompasses both the conventional refrigerants known in the art and any other suitable heating means or refrigerants , For example, if in a particular application the heat exchanger is a simple radiator, for example a radiator in an internal combustion engine, then the heating means may be in the Special, of course, simply be water or oil, which circulates as a coolant through the heat exchanger.

In any case, the surrounding medium, e.g. the air, a much lower heat transfer coefficient than the second medium, e.g. the coolant that circulates in the heat exchanger system. This is due to very different heat transfer surfaces for the two media

balanced: The medium with the high heat transfer coefficient, ie the heat medium, flows in the tube, which on the outside by thin sheets (ribs, fins) has a greatly enlarged surface at which the heat transfer, for. takes place with the air.

FIG. 2 shows a heat exchange system according to the invention with a laminated tubular heat exchanger known per se. In practice, the Wärmetau seh system is formed by a variety of such elements. The ratio of the outer surface to the inner surface depends on the lamella geometry (= pipe diameter, pipe arrangement and pipe spacing) and on the lamellar spacing. The slat distance is for

different applications chosen differently. Purely

thermodynamically, however, it should be as small as possible, but not so small that the air-side pressure drop is too large. An economic optimum is about 2 mm, which is a typical value for condenser and recooler.

The production of these so-called laminated tube heat exchangers is based on a long-known standardized process: The slats are punched with a press and a special tool and placed in packages to each other. Subsequently, the pipes

inserted and expanded either mechanically or hydraulically, so that a very good contact and thus a good heat transfer between Pipe and lamella are created. The individual tubes are then connected by arches and manifold and manifold, often soldered together.

The efficiency is essentially determined by the fact that the heat that is transferred between the fin surface and the air, must be transmitted through heat conduction through the fins to the pipe. This heat transfer is all the more effective, the higher the conductivity or the thickness of the lamella, but also the smaller the distance between the tubes. This is called the lamella efficiency. As a lamellar material is therefore nowadays predominantly aluminum used, which has a high thermal conductivity (about 220 W / mK) to economic conditions. The pipe pitch should be as small as possible, but this leads to the problem that you need many pipes. Many pipes mean high costs because the pipes (usually made of copper) are considerably more expensive than the thin aluminum fins. This material could be reduced by reducing the tube diameter and wall thickness, i. You build a heat exchanger with many small pipes instead of a few big pipes. Thermodynamically, this solution would be optimal: very many tubes in close proximity with small diameters. However, a significant cost factor is also the working time for expanding and soldering the pipes. This would increase extremely with such a geometry.

Therefore, a few years ago, a new class of heat exchangers, so-called Minichannel- or Mircochannelwärmetauscher or else

Microchannel heat exchangers have been developed that are manufactured using a completely different process, almost laminating the ideal image

Tubular heat exchanger correspond: many small tubes with small distances.

Instead of small tubes, however, the mini-channel heat exchanger

Aluminum extrusions used a very large number of small channels with one Diameter of eg about 1 mnn have. Such, also known per se extruded profile, for example, in the inventive

Embodiment of FIG. 1 used and shown schematically. In practice, a heat exchanger, depending on the required heat output, already with a single extruded profile as the central

Get along heat exchange element. To higher

Of course, in a single heat exchange system, it is also possible to provide a plurality of extruded profiles at the same time, which are connected together in suitable combinations, for example by means of connections and discharges, e.g. be soldered together.

Such profiles can e.g. be made easily and in a variety of forms from a variety of materials in suitable extrusion. But also other manufacturing processes for the production of

Mini-channel heat exchangers are known, such as e.g. the assembly of suitably shaped profile sheets or other suitable methods.

These profiles can not, and you do not need to widen and they are not inserted into stamped plate packs.

Instead, for example, between two closely spaced profiles (common distances, for example, <1 cm) sheet metal strip, especially aluminum sheet strips laid so that by alternately

juxtaposition of sheet metal strips and profile heat exchanger package is created. This package is then completely soldered in a soldering oven.

That is, even when using the mini-channel heat exchangers, to increase the surface area and to improve the heat transfer, for example, between the heat medium, the inside of the

Minnichannel heat exchanger flows, and the air, for example, heat should be issued, similar to the laminated tubular heat exchange also often used fins.

It is known in both types of heat exchangers to provide the lamellae with slots, so-called "louvers." As is well known to those skilled in the art, the louvers are usually roof-shaped

Exhibitions in the lamellar surfaces, by the one hand, e.g. air

can flow through, on which, on the other hand, but also turbulence of the air can form, so that an effective contact time or an effective contact area between the air to be exchanged with the heat, and the fins is additionally increased, so that the efficiency of

Heat exchange can be further increased. This measure has long been known, the specific geometric design of the Louver depending on the application can be very different. In the simplest case, a Louver simply a slot, so an elongated narrow recess or opening in the lamella.

Due to the narrow distances and the small channel diameter in the

Microchannel heat exchangers create a heat exchanger with a very high fin efficiency and a very small filling volume

(Duct inner side). The other advantages of this technique are the avoidance of material pairings (corrosion), the low weight (no copper), the high pressure stability (about 100 bar) and the compact design (typical depth of a heat exchanger, for example 20mm).

In mobile use, mini-channel heat exchangers have established themselves during the 1990s. The low weight, the low block depth and the limited dimensions required here are the ideal ones

Requirements for this. Car coolers and condensers and evaporators for car air conditioning systems are today almost exclusively with

Minichannel heat exchangers realized. In the stationary area, on the one hand, larger heat exchangers are usually needed; on the other hand, the emphasis here is less on weight and compactness than on the optimal price-performance ratio.

Minichannel heat exchangers were previously limited in size to be eligible. Many small modules would have to be connected consuming. In addition, the use of aluminum in the extruded profiles is relatively high, so that hardly a cost advantage was expected from the use of materials.

Above all, however, the price of copper, which has risen sharply compared with aluminum, is now causing this technology to become increasingly interesting for stationary use as well.

A problem with all previously known heat exchange systems is the pollution of the system components of the system Wärmetau seh, in particular the heat exchanger itself, that is, especially the fins of the heat exchanger, which in principle not in the operating condition

avoid.

Air-applied heat exchangers, such as e.g. Condensers or recoolers often work in contaminated environments. Contamination of the air may be natural (pollen, insects, dust, leaves, etc.) or industrial (grinding dust, tire wear, flour dust, cardboard dust, etc.). Many impurities remain on the airborne

Heat exchangers hang and add to it over time.

The heat exchangers, where, for example, the cooling air is guided past with the aid of appropriate fan can be polluted by such and other contaminants of all kinds that are contained in the cooling air with time more and more, which may for example lead to the heat transfer coefficient of the surface of the heat exchanger is lowered, so that the heat transfer performance is significantly reduced. This can lead to increased operating costs or in extreme cases, the heat exchange system can no longer provide the required heat exchange performance, which can lead to serious damage in the worst case.

Particularly susceptible to contamination are the above-mentioned Louvers. Especially these provide a good grip for all types of contamination. The dirt accumulates on the edges of the Louvers in the slats and thus lead to a deterioration of the heat transfer of the lamella and thus to loss of performance of the heat exchanger, resulting in an increase in consumption of Energy, right down to one

Operational standstill can lead.

The consequence of the contamination is thus very frequent, that the air-side resistance increases and thereby the air flow rate is reduced and also the heat transfer is reduced. As a result, a connected machine to be cooled, such as a data processing system or an internal combustion engine or other machine may overheat and be damaged. But even damage to goods, such as food that is stored in a cold store, can spoil, for example, in the absence of cooling.

This problem occurs both in laminated tube heat exchangers as well as in the provided with fins Mikokanalwärmetauschern.

To prevent such serious damage and such

To counteract contamination, the heat exchanger must be either regularly cleaned consuming or provided with an appropriate filter. However, the filters must be cleaned regularly. It is in the known systems, the cleaning of the heat exchanger alone for design reasons, for example because of

Heat exchanger in the installed state is not readily accessible directly, cumbersome so consuming and expensive. In many known

For example, heat exchange systems require opening a housing, e.g. the heat exchanger itself or other essential

To clean components inside the housing of the heat exchange system or just to check if cleaning is necessary or maybe even postponed. The opening of the housing is not only complicated and cumbersome. Also, in this case, the corresponding connected heat engines must be put out of service as already mentioned, otherwise opening of the housing of the heat exchange system alone is not allowed for security reasons or for technical reasons in the operating state is not possible. Another point is that time-increasing pollution can be compensated within certain limits by appropriate control and / or regulation of the heat exchange system, e.g. by adjusting the performance of a fan conveying the air for heat exchange through the heat exchanger in terms of its performance as a function of the degree of soiling. Or by a flow rate or an operating pressure of a heating medium is readjusted by the heat exchanger suitable or another operating variable is adjusted accordingly.

All these measures presuppose, however, that the degree of

Pollution of the heat exchange system must be known, and although preferably not only qualitatively but also quantitatively must be known and especially the change in pollution as a function of time must be detectable. The object of the invention is therefore to provide an improved

To provide heat exchange system, which overcomes the problems known from the prior art and in particular allows to continuously monitor the degree of contamination of the heat exchange system, in particular the fins of the heat exchanger. In particular, a heat exchange system is proposed in which certain relevant Bethebsgrössen can be adapted to the changing pollution of the heat exchange system, so that a heat transfer performance of the heat exchanger or the entire heat exchange system can be optimized over a longer period of operation, and also over long periods of operation a predefinable

Heat transfer performance is guaranteed even with increasing pollution. In addition to be ensured by the invention that a predeterminable degree of contamination is detected automatically, so that the optimal time for necessary cleaning work is automatically recognizable without much effort.

The objects of the invention solving these objects are characterized by the features of independent claims 1 and 11.

The dependent claims relate to particularly advantageous

Embodiments of the invention.

The invention thus relates to a heat exchange system comprising a

Heat exchanger with a arranged in a flow segment

Flow channel. To exchange heat between one

Transport fluid and a flowing through the flow channel in the operating state heating means is the Transportfluidum on a

Inlet surface can be brought into flowing contact with the heat exchanger, and via an outflow from the heat exchanger again wegführbar.

According to the invention is for determining a degree of contamination of the Heat exchanger provided a pollution sensor in the form of a pressure sensor and / or a speed sensor, with which a

Transport characteristic, which is characteristic of the flow of the transport fluid from the inflow over the outflow surface determinable. By the inventive pollution sensor, the

monitored characteristic characteristic, it is now possible to automatically and continuously monitor a time-increasing pollution of the heat exchange system, wherein a decrease in power of the heat exchanger by means of the invention

Pollution sensor is already detected before the pressure drop across the heat exchanger increases significantly. It is in fact an essential realization of the invention that the power take-off of the heat exchanger is already used massively even at a degree of contamination in which the increasing contamination of the heat exchanger does not lead to an increase in the pressure loss across the heat exchanger. But in the

Conversely, at a fairly early stage of pollution, a drop in pressure loss across the heat exchanger results.

That is, by the present invention it is possible for the first time, from the characteristic transport characteristic of the heat exchanger, for example, from the pressure drop across the heat exchanger or from a

Flow rate of the transport fluid, e.g. the one by the

Heat exchanger air flowing to draw reliable conclusions about the performance or the change in performance to the heat exchanger.

As a result, for example, by appropriate control and / or regulation of the heat exchange system within certain limits an increasing

Contamination of Wärmetau seh system are compensated, for example, by a performance of a fan, which conveys the air for heat exchange through the heat exchanger, in its performance as a function of Pollution degree is adjusted. Or by a flow or an operating pressure of a heating medium is suitably readjusted by the heat exchanger or another operating variable is adjusted accordingly. It is possible in a particularly important for practice embodiment of the present invention, to determine the degree of contamination of the heat exchange system continuously, if necessary not only qualitatively, but also quantitatively, in particular, the

Change in pollution as a function of time is detectable. That is, the degree of contamination of the heat exchange system, in particular of the fins of the heat exchanger can in the inventive

Heat exchange system to be monitored continuously.

This allows certain relevant within specified limits

Operating variables to the changing pollution of the

Systematically adjust heat exchange system, so that a

Heat transfer performance of the heat exchanger or the entire heat exchange system even over a longer period of operation, even with increasing pollution is constantly optimized, which also over long periods of operation regardless of the pollution of the

Heat exchanger ensures a predetermined heat transfer performance. A predefinable degree of contamination can be automatically detected by the invention, so that the optimum time for necessary cleaning and maintenance is automatically recognizable without much effort. The invention is based on the knowledge that a

characteristic transport characteristic of the transport fluid in a clear and reproducible manner from the degree of contamination of the Heat exchange system, in particular the degree of soiling of

Heat exchanger depends.

The transport parameter can, for example, a

Flow rate of the transport fluid through the heat exchanger, so for example, a flow rate of air through the heat exchanger. However, the transport characteristic may also be a pressure of the transport fluid, for example a pressure of the air before it enters the heat exchanger via the inflow surface, or a pressure during or after the outflow over the outflow surface of the heat exchanger. Particularly preferably, the transport parameter is a pressure difference or a pressure drop across the heat exchanger. As will be explained in detail later with reference to FIGS. 4 and 5, it has been found in experiments that increasing contamination of the heat exchanger affects the pressure loss of the flowing transport fluid in a characteristic manner as a function of the degree of soiling.

By appropriate calibration measurements, for example, a look-up table or a mathematical function can be generated, which reflects the degree of soiling of the heat exchange system depending on the pressure loss and / or an absolute pressure value and / or a characteristic flow velocity of the transport fluid, possibly further parameters such For example, the speed of a fan, a temperature or other parameters or operating and

State variables of the heat exchange system are taken into account. Which parameters are to be taken into account in detail for the determination of the degree of contamination, the expert knows and hangs

Of course, from the specific execution of a corresponding heat exchange system. Particularly advantageous, the invention can be used in heat exchangers that a blade to increase the effective

Heat transfer surface, wherein the blade is preferably equipped with the initially provided Louvern. Surprisingly, the contamination of the Louvers initially leads to a reduced pressure loss, as will be explained later with reference to FIG. 5. Here, the pressure loss as a function of the amount of pollution initially falls to a minimum, and then increase again as pollution progresses. That means, the

Pressure loss across the heat exchanger initially decreases with increasing pollution, completely different than expected.

It is an essential finding of the invention that the increasing pollution of the Louvers, especially the edges but also the

Opening slots of the Louvers, the turbulence especially at the edges of the Louvers reduced or minimized or even pollution is prevented completely, so that less turbulence and thus the total pressure loss formed by the lamella

Flow channel is reduced. That is, the associated

Decrease of the heat exchanger results from the reduction of the turbulence at the Louvers because it reduces the effective contact time or the effective contact area of the transport fluid with the heat exchanger.

Taking advantage of this knowledge can be in a special

Embodiment, a very simple contamination sensor for measuring the pressure loss installed on a novel heat exchange system that detects a drop in pressure loss across the heat exchanger and thus can measure the degree of pollution, preferably time-dependent. In particular, it should be ensured that the Air quantities at which the respective pressure drop across the heat exchanger is measured, in each case in the clean and soiled state in the

Are essentially the same. The speeds of the fan and more

Ambient conditions should therefore be largely the same between clean and dirty state. For example

Variable speed fans according to EC technology can, among other things, also use the current consumption of the motor as a signal.

As already mentioned several times, a lamella can be provided in a particularly important embodiment for increasing the rate of heat exchange on a flow segment, wherein a flow-through opening, in particular in the form of a Louver, is preferably provided on the lamella.

In this case, at least one heat exchanger of an inventive

Heat exchange system a microchannel heat exchanger and / or at least one heat exchanger is a tubular heat exchanger.

Usually, in practice, in a heat exchange system of the present invention, a transport device is known per se in a manner known per se.

in particular, a fan may be provided for transporting the transport fluid from the inflow surface to the outflow surface, wherein in practice the transport fluid is very often the ambient air.

As also already mentioned, the transport characteristic variable can be a pressure of the transport fluid, in particular a pressure loss between the transport fluid

Be inflow and the outflow of the heat exchanger, and / or the transport characteristic may have a flow velocity of the

Transport fluid and / or another characteristic

Be flow characteristic of the transport fluid. For controlling and / or regulating and / or for the purpose of data acquisition of an operating or state parameter of the heat exchange system, a drive unit, in particular one, is particularly advantageous

Drive unit with a data processing system with a sensor of the heat exchanger and / or with the transport device and / or with the pollution sensor and / or with a heat engine

signal-connected.

In practice, the inventive heat exchange system may be a radiator, in particular a radiator for a vehicle, in particular for a land vehicle, for an aircraft or for a watercraft, or a radiator, a condenser or an evaporator for a mobile or stationary heating system, cooling system or air conditioning, especially one

Cooler device for a machine, a data processing system or for a building. The invention further relates to a method for operating a described heat exchange system according to the present invention, wherein a transport characteristic variable is measured, and from the transport characteristic a degree of contamination of the heat exchanger is determined.

In an embodiment which is particularly important for practice, a pressure drop across the heat exchanger is ascertained from the transport characteristic variable, with it being possible in particular to determine a decrease in heat transfer performance of the heat exchanger from the pressure loss.

In this case, a power of the transport device, in particular a rotational speed of the fan depending on the degree of contamination of the

Heat exchanger controlled and / or regulated and / or a

Time for a maintenance routine can be determined automatically, for example, depending on the degree of contamination. Advantageously, in a heat exchange system according to the invention in an online process, in particular via an intranet and / or the Internet, operating and / or status data are monitored by a control center and / or the heat exchange system is controlled and / or regulated in this manner.

In the following the invention will be explained in more detail with reference to the drawing. In a schematic representation:

Fig. 1 shows a first embodiment of an inventive

Heat exchange system with microchannel heat exchanger;

Fig. 2 shows a second embodiment according to FIG. 1 with laminated

Tube heat exchanger;

Fig. 3 shows an embodiment with differential pressure measurement for

Determination of a pressure loss; Fig. 4 pressure loss at different levels of contamination in

Dependence on the flow rate of the transport fluid;

Fig. 5 pressure loss and power curve as a function of

Pollution degree.

1 is a schematic representation of a first embodiment of an inventive heat exchange system with a Microchannel heat exchanger shown, which is provided throughout the following by the reference numeral 1.

The heat exchange system 1 according to the invention of FIG. 1 comprises a heat exchanger 2, which in the present example is a known per se

Microchannel heat exchanger 2, with a flow channel 210 arranged in a flow segment 21. For exchanging heat between a transport fluid 3, which in the present case is the ambient air, and a heat medium 4 flowing through the flow channel 210 in the operating state, which is, for example, a refrigerant 4, such as CO ₂ , the Transportfluidum 3 via an inflow surface 201 with the heat exchanger 2 in flowable contact and via an outflow surface 202 of

Heat exchanger 2 wegführbar.

According to the present invention, a contamination sensor 5 is provided for determining a contamination of the heat exchanger 2, which is arranged in the flow direction of the air 3 in front of the disk set of lamellae 6 in the present example. The contamination sensor 6 is either a pressure sensor 6 or a speed sensor 6 or another suitable pollution sensor 6, with which a transport characteristic TK, which is characteristic of the flow of the transport fluid 3 from the inflow surface 201 via the outflow surface 202, can be determined.

The plate pack with the plurality of fins 6 with fin surface 62 serves to increase a heat exchange rate between the

Flow segment 21 and the Transportfluidum 3, which is ambient air 3 in the present example.

In the embodiment of FIG. 1, any existing louvers are not explicitly shown. It can thus with a special Embodiment according to FIG. 1 Louver be provided on the blade 6 and not in another embodiment, because no Louver needed for a corresponding other application.

In practice, a fan 7 (not shown in FIG. 1 for reasons of clarity) for transporting the air 3 through the pack of lamellae 6 is provided so that, for example, a flow rate LG according to FIG. 4 can be set, for example as a function of a thickness the pollution of the heat exchanger 2, with the help of

Pollution sensor 5 has been detected. The Transportfluidum air 3 is doing by the fan 7 in the direction of arrows 3 through the package

Slats 6 blown.

Clearly visible in Fig. 1, which relates to an inventive

Embodiment with a micro-channel heat exchanger 2, the plurality of flow channels 210, which are here micro-channels 210. Fig. 2 differs from the embodiment of Fig. 1 essentially only in that instead of a micro-channel heat exchanger 2, a classic laminated tube heat exchanger 2 is used, wherein clearly the Louver 61 can be seen in the slats 6, in the example of Fig. 2 yet are not polluted. Another difference to the example of Fig. 1 is that the pollution sensor 5 is housed within the disk set of lamellae 6.

It goes without saying that in each inventive

Embodiment also other pollution sensors 5 alternatively arranged at suitable locations or in addition several

Pollution sensors 5 may be provided simultaneously.

For very special arrangements, it is even possible that in one and the same heat exchange system simultaneously a micro-channel heat exchanger. 2 and a conventional laminated tube heat exchanger can be provided simultaneously.

In Fig. 3 is another, very significant in practice embodiment with differential pressure measurement for determining a pressure drop .DELTA.P across the heat exchanger 2 is shown schematically. The fan 7 conveys in a conventional manner ambient air 3 with the characteristic

Transport characteristic TK on the inflow 201 through the

Heat exchanger 2 and leads the air 3 via the discharge surface 202 by a cover A from the heat exchange system 1 back to the environment. To determine the pressure loss .DELTA.P in the passage of the air 3 through the heat exchanger 2 are respectively in accordance with the left before

Einströmfläche 201 and according to the representation right behind the discharge surface 202 a pollution sensor 5 is provided so that from a

measured pressure difference of the pressure loss .DELTA.P via the heat exchanger 2 can be determined.

It is understood that it is not primarily relevant to the invention by which means the pressure loss .DELTA.P is determined. So it can also be used advantageously another known differential pressure gauge. In Fig. 4 is finally still a typical characteristic of the

characteristic transport characteristic TK for a heat exchange system 1 with a microchannel heat exchanger 2 with lamellae 6 and Louvern 61

shown schematically.

In the example of FIG. 4 as the transport characteristic value TK, the pressure loss .DELTA.P at various levels of contamination V, (V _0, V _1, .... to V _max) in

Depending on the flow rate LG of the transport fluid 3 applied. The expert understands without problems, that one

corresponding characteristic fields also for other transport parameters TK, for example, for the flow rate, etc. can create and

of course also for other types of heat exchangers, e.g. for a laminated pipe heat exchanger.

The curve V ₀ belongs to a heat exchange system 1, which has been freshly cleaned, that is not dirty yet. After a certain period of operation was in the same heat exchanger system 1, the curve Vi of

Characteristic field recorded. The heat exchanger 2 is now already much more polluted, which can be seen in the corresponding smaller pressure drop .DELTA.P. The curve Vi runs much flatter than the curve V ₀ , which belongs to the un polluted heat exchanger 2. After further operation, the heat exchanger 2 is getting more and more polluted until finally it has the maximum permissible contamination via V ₂ , V ₃ , etc. at the curve V _max and must be cleaned again.

Finally, FIG. 5 shows a schematic diagram of a characteristic diagram which explains the relationship between the degree of contamination V and the resulting change in the pressure loss ΔP and the associated decrease in the heat transfer capacity PW of the heat exchanger 2.

On the horizontal abscissa is the degree of pollution V of

Heat exchanger 2 shown, which increases according to the illustration from left to right, wherein on the left axis of ordinate .DELTA.P the pressure loss .DELTA.P is plotted on the heat exchanger 2, while on the right

Ordinatenachse PW at the same time from the increasing

Pollution degree V resulting decrease in

Heat transfer power PW is read.

The solid line ΔP corresponds to the curve of the pressure loss .DELTA.P as a function of the degree of contamination V, while the dotted line the drop in the heat transfer power PW as a function of

Pollution degree V shows. The pressure loss ΔP and the

Heat transfer power PW are at a pollution level V identical zero, that is normalized for the non-polluted heat exchanger 2 each to 100%.

At even less pollution V, the pressure drop .DELTA.P across the heat exchanger 2 initially remains almost constant up to a critical

Pollution degree VK, from which the pressure loss ΔP continues

Increasing pollution level V abruptly and significantly decreases until the value of the pressure loss .DELTA.P reaches a minimum value at a degree of contamination Vm. At the same time, the heat transfer performance PW drops rapidly. Before and in the soiling interval between VK and Vm, essentially only the Louvers 61 initially sit down

Dirt particles too, which causes, the turbulence of the

Transport fluid 3, e.g. the more the Louvers 61 are clogged with dirt, the more the air 3 flowing through the heat exchanger 2 is reduced. The air 3 can thereby pass through the heat exchanger 2 easier and / or faster. On the one hand, this results in a reduction of the pressure loss ΔP and, on the other hand, reduces the effective contact time or the effective contact area between transport medium 3 and heat exchanger 2, which results in the observed massive reduction of the heat transfer power PW.

With even more pollution, the pressure loss ΔP increases again. The reason for this is that now increasingly the spaces between the individual slats, in which the Louvers 61 are incorporated, are clogged by dirt, so that less and less air 3 can be transported through the heat exchanger 2 per unit time with the same fan performance. It is essential that in the vicinity of the minimum of the pressure loss .DELTA.P, the heat transfer power PW has already dropped to a no longer tolerable level, in the present specific example has already dropped to 50% of the maximum possible heat transfer power PW. It is thus an essential realization of the invention that a cleaning of the heat exchanger is not carried out only at an increasing pressure loss .DELTA.P, but much earlier, namely in a phase when the pressure loss .DELTA.P drops significantly.

Thus, with the present invention on the one hand the maintenance of cleaning intervals can be optimally ensured, and on the other hand, an optimally designed operation of the inventive heat exchanger system can be guaranteed. Furthermore, the quasi-automatically incurred electronic signals are also available for other purposes and can for example also be used advantageously for various service purposes.

Claims

claims

1 . A heat exchange system comprising a heat exchanger (2) with a flow channel (210) arranged in a flow segment (21), wherein for exchanging heat between a transport fluid (3) and the flow channel (210) in the operating state

by flowing heat means (4), the Transportfluidum (3) via an inflow (201) with the heat exchanger (2) is brought into flowing contact, and via an outflow surface (202) from the heat exchanger (2) is again wegführbar, characterized in that Determining a degree of contamination (V) of the heat exchanger (2)

Pollution sensor (5) in the form of a pressure sensor (5) and / or a speed sensor (5) is provided, with which a Transportkenngrösse (TK), for the flow of the transport fluid (3) from the inflow surface (201) via the outflow surface (202 )

is characteristic, determinable.

2. Wärmetau see system according to claim 1, wherein to increase a

Heat exchange rate at a flow segment (21) a blade (6) is provided.

3. Wärmetau see system according to claim 2, wherein on the blade (6) has a flow-through opening (61), in particular in the form of a Louvers (61) is provided.

4. Wärmetau see system according to one of the preceding claims, wherein at least one heat exchanger (2) is a micro-channel heat exchanger (2).

5. Wärmetau see system according to one of the preceding claims, wherein at least one heat exchanger (2) is a tubular heat exchanger (2).

6. Wärmeta u seh system according to one of the preceding claims, wherein a transport device (7), in particular a fan (7) for transporting the transport fluid (3) from the inflow (201) to

Outflow surface (202) is provided.

7. Wärmetau see system according to one of the preceding claims, wherein the transport characteristic variable (TK) is a pressure of the transport fluid (3), in particular a pressure drop (.DELTA.P) between the inflow surface (201) and the outflow surface (202) of the heat exchanger (2) ,

8. Wärmetau seh system according to one of the preceding claims, wherein the transport characteristic variable (TK) a flow velocity of the

Transport fluid (3) is.

9. Wärmetau seh system according to any one of the preceding claims, wherein for the control and / or regulation and / or for the purpose of

Data acquisition of an operating or status parameter of the

Heat exchange system, a drive unit, in particular a

Control unit with a data processing system with a sensor of the heat exchanger (2) and / or with the transport device (7) and / or with the pollution sensor (5) and / or with a

Heat engine is signal connected.

10. Heat exchange system according to one of the preceding claims, wherein the Wärmetau seh system is a radiator, in particular a radiator for a vehicle, in particular for a land vehicle, for an aircraft or for a watercraft, or a radiator, a condenser or an evaporator for a mobile or stationary heating system, cooling system or air conditioning, in particular a cooler device for a

Machine, a data processing system or for a building.

1 1. Method for operating a heat exchange system (1) according to one of the preceding claims, wherein a transport parameter (TK) measured and from the transport characteristic (TK)

Pollution degree (V) of a heat exchanger (2) is determined.

12. The method of claim 11, wherein from the transport characteristic variable (TK), a pressure drop (.DELTA.P) is determined.

13. The method of claim 11 or 12, wherein a decrease in a

Heat transfer capacity (PW) of the heat exchanger (2) from the pressure loss (ΔP) is determined.

14. The method according to any one of claims 11 to 13, wherein a power of the transport device (7), in particular a rotational speed of the fan (7) depending on the degree of contamination of the heat exchanger (2) is controlled and / or regulated and / or wherein a time for a maintenance routine is automatically determined depending on the degree of contamination.

15. The method according to any one of claims 11 to 14, wherein of

Heat exchange system (1) in an online process, in particular via an intranet and / or via the Internet, operating and / or

Monitoring status data from a control center and / or the heat exchange system (1) is controlled and / or regulated.