JP2012532306A - Heat exchange system and method of operating a heat exchange system - Google Patents

Abstract

  The present invention relates to a heat exchange system 1 including a heat exchanger 2 with a flow path 210 arranged in a flow segment 21. For the heat exchange between the transport fluid 3 and the heating means 4 flowing through the flow path 210 in the operating state, the transport fluid 3 is brought into flow contact with the heat exchanger 2 by the inflow region 201 and the outflow region. 202 can be led away from the heat exchanger 2. According to the present invention, a dirt sensor 5 in the form of a pressure sensor 5 and / or a speed sensor 5 is provided in order to determine the degree V of dirt in the heat exchanger 2, by means of the dirt sensor. A transport parameter TK specific to the flow of transport fluid 3 across the surface 202 can be determined. Furthermore, the present invention relates to a method for operating the heat exchange system 1.

Description

  The invention relates to a heat exchange system according to the introductory part of independent claims 1 and 11 and to a method of operation and determination relating to the degree of contamination of the heat exchange system.

  The use of heat exchange systems is known in numerous applications from the prior art. Heat exchangers are used in ordinary cooling equipment such as household refrigerators, in buildings or in all types of vehicles, especially in air conditioning equipment in automobiles, aircraft and ships, as water or oil radiators in combustion engines, for example heat pumps etc. It is used as a condenser or vaporizer in a coolant circuit, and indeed in a myriad of other applications that are all well known to those having average skill in the art.

  In this regard, there are various ways to make meaningful classifications of heat exchangers, unlike completely different areas of use. One attempt is to classify according to different types of heat exchanger configurations and / or manufacturing differences.

  Thus, on the one hand, so-called “finned heat exchangers”, sometimes called “tube heat exchangers”, and on the other hand “mini passage heat exchangers” or “micropass heat exchangers (micro) -Passage heat exchanger) ".

  As is the case with all types of heat exchangers, fin tube heat exchangers, well known for their very long service life, serve for heat transfer between the two media. The heat transfer between the two media is, for example, but not limited to, the transfer from one cooling medium to the air or vice versa. It is known, for example, from a typical household refrigerator. Inside the refrigerator, heat is released to the ambient air through a heat exchanger to create cooling capacity.

  The environmental medium outside the heat exchanger, i.e. water, oil, or often simply simply the atmosphere that receives or transfers heat to the heat exchanger, for example, is likewise cooled or heated in this respect. The second medium may be a liquid cold or heat transfer medium, or a “heat transfer medium” that vaporizes or condenses. Within the scope of the present application in this regard, the term “heat transfer medium” is understood to mean any fluid that can be advantageously used in a heat exchanger. Thus, the term “heat transfer medium” includes not only typical coolants known in science and technology, but any other suitable heat transfer medium or cooling means. For example, in certain applications, if the heat exchanger is a simple radiator, for example a radiator in a combustion engine, the heat transfer medium more specifically, of course, passes through the heat exchanger as a coolant. It may be just water or oil that circulates.

  In any case, the environmental medium, for example air, has a much lower heat transfer coefficient than the second medium, for example the coolant circulating in the heat exchange system. This is compensated by very different heat transfer surfaces for the two media. A medium having a high heat transfer coefficient, that is, a heat transfer means, flows in the pipe, and the pipe has a surface greatly enlarged outward by metal thin plate portions (ribs, fins), for example, heat transfer with air is performed. Is called.

  FIG. 2 shows a heat exchange system according to the invention having a finned tube heat exchanger which is known per se. In this regard, the heat exchange system is actually formed by a plurality of such elements.

  In this regard, the ratio of the outer surface to the inner surface also depends on the fin shape (= tube diameter, tube placement and tube spacing) and fin spacing. Fin spacing is variously selected for various uses. However, from a pure thermodynamic point of view, the spacing should be as small as possible, but not so small that the pressure loss on the air side becomes too great. The economic ideal is about 2 mm, which is typical for liquefiers and heat exchangers.

  The manufacture of such so-called finned tube heat exchangers is carried out according to standardized procedures that have been known for many years. The fins are stamped using a press and special tools and placed together as a pack. The tube is then pushed and spread mechanically or by hydraulic pressure so that a very good contact and thus a good heat transfer between the tube and the fin occurs. The individual tubes are then connected to one another by an arcuate body, often collecting and dispensing the tubes and soldering to each other.

  Here, the degree of efficiency is essentially determined by the fact that the heat transferred between the fin surface and air must be transferred by heat conduction through the fin to the tube. The more effective this heat transfer, the greater the conductivity or thickness of the fins and the smaller the spacing between pipes. In this regard, the degree of fin efficiency will be described. For this reason, aluminum is mainly used today as a material for fins, but aluminum has a high thermal conductivity (about 220 W / mK) in economical conditions. The spacing between the tubes should be as small as possible, but this leads to the problem of requiring a large number of tubes. Since tubes (generally made of copper) are considerably more expensive than thin aluminum fins, the cost increases with the number of tubes. The cost of such materials can be reduced by reducing the diameter of the tubes and the strength of the walls, i.e. building a heat exchanger with a large number of small tubes instead of a small number of large tubes. Thermodynamically, this solution would be ideal where a very large number of tubes with small diameters are spaced closely together. However, the working time for expanding and soldering the tube is also a very important cost factor. This will be very large in such scenarios.

  For this reason, a new kind of heat exchanger was developed several years ago. This heat exchanger is a so-called small passage heat exchanger or a small passage heat exchanger, or a micro-channel heat exchanger. This heat exchanger is manufactured by a completely different process and almost matches the ideal concept of a finned tube heat exchanger with a large number of small tubes with narrow spacing.

  In small-path heat exchangers, aluminum extrudates are used instead of small tubes, but this heat exchanger has a very large number of small paths, for example having a diameter of about 1 mm. For example, in the embodiment of FIG. 1 according to the invention, such an extruded part, also known per se, is used and schematically shown. In this regard, depending on the required heat output, the heat exchanger can in fact be a single extrusion part as a central heat exchange element. In order to obtain a higher heat transfer performance, it is of course also possible to provide a plurality of extruded parts simultaneously, which are connected together or soldered together, for example in a suitable combination via an inlet conduit and an outlet conduit. Is done.

  Such parts can be easily manufactured in a variety of shapes from multiple materials, for example, with a suitable extrusion procedure. However, other manufacturing methods are also known for the manufacture of small passage heat exchangers, such as assembling appropriately shaped sheet metal parts or other suitable methods.

  These parts cannot be unfolded, do not need to be unfolded, and are not pushed into the punched fin pack. Instead, two molded metal sheets, for example, metal sheet pieces, in particular aluminum pieces, are close to each other so that a heat exchange pack can be obtained by alternately arranging the pieces of metal sheets and parts. Between the parts (eg a typical spacing of less than 1 cm). The pack is then totally soldered in a soldering oven.

  This increases the surface even when using a small passage heat exchanger and improves the heat transfer between the heat transfer medium flowing into the interior of the small passage heat exchanger and, for example, air from which heat is released. For this reason, fins are often used in the same way as fin tube heat exchangers.

  In this regard, it is known to provide fins with slits, so-called “louvers”, in both types of heat exchangers. As will be appreciated by those having an average skill in the art, these louvers are mostly roof-shaped protrusions formed on the surface of the fin, while air passes through it, for example. On the other hand, there can be turbulence of the air, resulting in a further increase in the effective contact time or effective contact surface between the heat-exchanged air and the fins, and the heat exchange The efficiency can be further increased. This means has also been known for a long time, and the special shape design of the louver may vary greatly depending on the application. In the simplest case, the louver is simply a slit, an elongated narrow groove in the fin or an opening in the fin.

  In a small passage heat exchanger, the space is small and the passage diameter is small, so that the efficiency of fins is extremely high, and a heat exchanger with a very small volume (inside the passage) is obtained. Other advantages of this technology are avoidance of material bonding (corrosion), light weight (not copper), high pressure stability (about 100 bar), and compact type structure. (For example, the typical depth of a heat exchanger is about 20 mm).

  The small passage heat exchanger itself was established in the 1990s for portable applications. Light weight, small block depth, and the limited dimensions required here are ideal prerequisites for this. The liquefiers and vaporizers for automotive radiators and vehicle air conditioning units are now mostly realized using small passage heat exchangers.

  On the one hand, use in a fixed position often requires a larger heat exchanger, and on the other hand it is important in this case to be less heavy and compact, but rather financially ideal. It is much more important to be a reasonable value. To suit this application, small passage heat exchangers have been limited in size to date. Multiple small modules had to be connected in a complex and costly way. Furthermore, the use of aluminum in the extruded part is relatively high, and therefore, the cost advantage of using this material was hardly expected.

  However, this technology is also becoming more and more interesting for fixed applications, especially due to the sudden rise in the price of copper compared to aluminum.

  In this regard, a problem with all previously known heat exchange systems is contamination of the heat exchange system components, in particular the heat exchanger itself, i.e., among other things, the heat exchanger fins. It is basically unavoidable in the operating state.

  Air-cooled heat exchangers such as liquefiers or return exchangers often operate in a contaminated environment. Air pollutants can be from nature (pollen, insects, dust, leaves, etc.) or from industry (grinding dust, tire wear, powder dust, cardboard dust, etc.). Many contaminants stick to the air-cooled heat exchanger and gradually clog the air-cooled heat exchanger.

  For example, a heat exchanger in which cooling air is directed through the heat exchanger with the help of a corresponding fan can eventually become more and more contaminated by such contaminants, or any other type of contaminant contained in the cooling air. There is sex. For example, this may lead to a decrease in the heat conduction coefficient of the surface of the heat exchanger, and as a result, the heat conduction performance is significantly reduced. For this reason, operation cost may become high. Or, in extreme cases, the heat exchange device can no longer provide the required heat exchange performance. In the worst case it can lead to serious damage.

  In this regard, the aforementioned louvers are particularly susceptible to contaminants. In particular, louvers provide a convenient support for all types of contaminants. Contaminants collect at the edge of the louver in the fin, thus degrading the heat transfer of the fin and thus losing the performance of the heat exchanger, resulting in increased energy consumption and even a possible outage.

  Thus, contaminants often increase the resistance on the air side, resulting in a reduction in airflow volume and heat transfer. This can cause the engine to be cooled, such as a data processing unit, combustion engine, or other engine, to overheat and be damaged. Due to the lack of cooling, damage to commodities such as food stored in cold storage, for example, can be exacerbated.

  In this regard, such problems occur in both fin tube heat exchangers and short path heat exchangers with fins.

  In order to prevent such serious damage and take measures against such pollutants, the heat exchanger is regularly cleaned at an expense, or the heat exchanger has a corresponding filter. Must be provided. However, the filter must also be cleaned regularly.

  In known systems in this regard, cleaning the heat exchange device is labor intensive and therefore complex and expensive. This is because, first of all, for structural reasons, for example, the heat exchanger cannot be easily accessed in the operating state. In many known heat exchange devices, for example, to clean the heat exchanger itself or other critical components inside the housing of the heat exchange system, or simply whether or not cleaning is necessary, In order to check whether it is possible to postpone, it is necessary to open the housing, for example. In this regard, opening the housing is not time consuming and complicated. In this case, however, as already mentioned, the correspondingly connected heat engines must be shut down. The reason is that otherwise the opening of the housing of the heat exchange system is not allowed for safety reasons, or the opening of the housing in the operating state is absolutely impossible for technical reasons.

  A further point is that, within certain limits, by suitable control of the heat exchange system and / or adjustment of the heat exchange system, for example, adapting the performance of the fan that directs air to heat exchange by the heat exchanger depending on the degree of contamination. It is possible to compensate for contamination that increases with time. Alternatively, the heat transfer medium flow through or working pressure is readjusted by a heat exchanger, or other operating parameters are adapted.

  However, all of these measures should ensure that the degree of contamination of the heat exchange system must be known, and that the degree of contamination should preferably be known quantitatively as well as qualitatively, especially confirming changes in contamination. It is assumed that it must be possible.

  The object of the present invention is therefore improved, overcoming the problems known from the prior art, in particular allowing to continuously monitor the degree of contamination of the heat exchange system, in particular the heat exchanger fins. To make available a heat exchange system. In particular, within certain limits, certain associated operating parameters are inherently varied so that the heat transfer performance of the heat exchanger or the entire heat exchange system can also be optimized over a long operating time. A heat exchange system is proposed which can be adapted to the contamination of the heat exchange system and can guarantee a predetermined heat transfer performance over a long operating time even if the contamination increases. Furthermore, the present invention guarantees that a predetermined degree of contamination is automatically recognized, so that it can automatically recognize an ideal time when a cleaning operation is required without much expense. .

  The subject matter of the present invention that satisfies this object is characterized by the features of the independent claims 1 and 11.

  The dependent claims relate to particularly advantageous embodiments of the invention.

  Accordingly, the present invention relates to a heat exchange system that includes a heat exchanger with a flow path disposed in a flow segment. For heat exchange between the transport fluid and the heat transfer medium flowing through the flow path in the operating state, the transport fluid is brought into flow contact with the heat exchanger via the inlet region and via the outlet region. It can be led away from the heat exchanger again. According to the invention, a contamination sensor in the form of a pressure sensor and / or a velocity sensor is provided for determining the degree of contamination of the heat exchanger, which is used to flow the transport fluid from the inlet region to the outlet region. The characteristic transport parameters can be determined.

  The contamination sensor according to the present invention, which monitors characteristic transport parameters, makes it possible for the first time to automatically and continuously monitor heat exchange system contamination that increases over time, leading to a significant pressure drop across the heat exchanger. Before it rises, the contamination sensor according to the present invention will recognize a decrease in the performance of the heat exchanger. That is, it is extremely important for the present invention to take advantage of the reduced power output of the heat exchanger, even if the increased heat exchanger contamination is such that it still does not lead to an increase in pressure loss across the heat exchanger. Recognition. On the contrary, this leads to a reduction in the pressure loss across the heat exchanger at an earlier stage.

  This can be attributed to the performance or performance of the heat exchanger from the characteristic transport parameters of the heat exchanger, such as the pressure drop across the heat exchanger, or the flow rate of the transport fluid such as air flowing through the heat exchanger. It means that the present invention makes it possible for the first time to obtain reliable information about changes.

  This means that increased contamination of the heat exchange system can be compensated within certain limits, for example by appropriate control and / or adjustment of the heat exchange system. That is, for example, in that the performance of a fan that directs air to heat exchange by a heat exchanger is adjusted according to the degree of contamination. Alternatively, on the other hand, the heat transfer medium flow-through or the operating pressure of the heat transfer medium is readjusted appropriately by the heat exchanger, or the different parameters are adjusted appropriately.

  In this regard, in a particularly suitable embodiment in practice, it is possible to determine the degree of contamination of the heat exchange system continuously and, if necessary, qualitatively as well as quantitatively. In particular, the change in contamination can also be determined as a function of time. That is, according to the present invention, the degree of contamination of the heat exchange system, in particular, the degree of contamination of the fins of the heat exchanger can be continuously monitored in the heat exchange system.

  This makes it possible to systematically adjust certain relevant parameters for heat exchange system contamination that varies essentially within a predetermined range. Thus, it is also possible to continuously optimize the heat transfer performance of the entire heat exchanger or heat exchange system during longer operating periods. As a result, the predetermined heat transfer performance can still be guaranteed during long operating times. The present invention automatically determines the degree of a given contamination so that it can automatically recognize the ideal time of cleaning and maintenance required, without much expense and complexity. It is possible to recognize.

  In this regard, the invention is based on the recognition that the characteristic transport parameters of the transport fluid depend in a clear and reproducible manner on the degree of contamination of the heat exchange system, in particular the degree of contamination of the heat exchanger. .

  In this regard, the transport parameter can be, for example, the flow rate of the transport fluid, i.e., the flow rate of air through the heat exchanger, for example. However, the transport parameter may be the pressure of the transport fluid, for example the pressure of air before entering the heat exchanger via the inlet region, or the pressure during or after exiting through the outlet region of the heat exchanger.

  It is particularly preferred that the transport parameter is the differential pressure or pressure loss across the heat exchanger. As will be described in detail later with reference to FIGS. 4 and 5, that is, in experiments, increasing heat exchanger contamination is characterized by a pressure drop in the flowing transport fluid in a characteristic manner depending on the degree of contamination. It has been shown to have an effect.

  It is possible to generate a look-up table or a mathematical function, for example with a corresponding calibration measurement. It reflects the degree of contamination of the heat exchange system depending on the pressure of the transport fluid and / or the absolute pressure value and / or the characteristic flow rate loss. Perhaps further parameters are taken into account, such as, for example, the rotational speed of the fan, temperature or other parameters, or operating and status parameters of the heat exchange system. Those with average skill in the art understand that specific parameters should be considered in determining the degree of contamination, and of course it depends on the actual design of the corresponding heat exchange system Is done.

  The present invention can be used particularly advantageously in heat exchangers that include fins to increase the effective heat transfer surface, and it is preferred that the fins comprise a louver initially specified.

  As will be explained later with reference to FIG. 5, i.e. louver contamination, in a completely surprising manner, first leads to a reduction in pressure loss. In this case, the pressure loss as a function of the degree of contamination first decreases to a minimum value and then increases again as contamination progresses. It was totally unexpected, but this meant that the pressure loss across the heat exchanger first decreased with increasing contamination.

  Increased contamination of the louver, especially the increased contamination of the opening slit along with the louver edge, reduces turbulence mainly at the louver edge, or minimizes or responds to turbulence at the louver edge It is very important for the present invention that in the case of contamination to be completely prevented, the resulting turbulence is reduced and thus the overall pressure loss through the flow path formed by the fins is reduced. Recognition. This means that the loss in heat exchanger performance associated with pressure loss is due to reduced turbulence in the louver. The reason is that the effective contact time or effective contact surface of the transport fluid with the heat exchanger is reduced.

  By taking advantage of this recognition, in a particular embodiment, a very simple contamination sensor can be introduced for the measurement of pressure loss in a heat exchange system according to the invention. The contamination sensor detects a reduction in the pressure drop through the heat exchanger and can therefore preferably measure the degree of contamination as a function of time. For this reason, it should be particularly ensured that the amount of air is essentially the same in clean and contaminated conditions. The respective pressure loss across the heat exchanger is measured against the amount of air. That is, the rotational speed of the fan at further environmental conditions should preferably be substantially the same between clean and contaminated conditions. For this reason, the charge rate of the engine, in particular, can be used as a signal in a ventilator whose speed is adjusted, for example by EC technology.

  As has been mentioned several times, in a particularly important embodiment in practice it is possible to provide fins to increase the heat exchange rate in the flow segment, on the fins, especially in the form of louvers. Is preferably provided.

  In this regard, at least one heat exchanger of the heat exchanger according to the invention is a short path heat exchanger and / or at least one heat exchanger is a tube heat exchanger.

  In practice, in the heat exchange system according to the invention, a transport device, in particular a fan, is provided in a manner known per se for the transport of transport fluid from the inlet region to the outlet region. Very often the atmosphere.

  Similarly, as already mentioned, the transport parameter is the pressure of the transport fluid, in particular the pressure loss between the inlet and outlet regions of the heat exchanger, and / or the transport parameter is the flow rate of the transport fluid, and / or Other characteristic flow characteristics of the transport fluid can also be provided.

  Particularly advantageous for control and / or adjustment and / or for recording data of operating parameters or status parameters of the heat exchange system is particularly advantageous for control units, in particular for control and / or adjustment and / or for heat. Control unit having a data processing unit in signal connection to a heat exchanger sensor and / or transport device and / or a contamination sensor and / or a heat engine for data collection of operating parameters or status parameters of the exchange system It is.

  In this regard, the heat exchange system is actually a radiator, in particular a radiator for a motor vehicle (land vehicles, aircraft or water vehicles in special cases), or a portable or stationary heating, cooling or air conditioning facility, in particular It can be a radiator, condenser or vaporizer for a cooling device for an engine, data processing system or building.

  Furthermore, the present invention relates to a method for operating a heat exchange system described according to the present invention. The transport parameters are measured and the degree of contamination of the heat exchanger is determined from the transport parameters.

  In an embodiment particularly important for implementation in this regard, the overall heat exchanger pressure drop can be determined from the transport parameters, and in particular the heat transfer performance degradation of the heat exchanger can be determined from the pressure loss.

  In this regard, the performance of the transport device, particularly the rotational speed of the fan, can be controlled and / or adjusted depending on the degree of contamination of the heat exchanger and / or the time for the service routine is It is automatically determined according to the degree.

  Advantageously, in the heat exchange system according to the invention, operating data and / or status data are monitored by the control center in an online manner, in particular via an intranet or the Internet, and / or the heat exchange system is thus controlled and / or controlled. Or adjusted.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. The drawings are shown schematically.

1 shows a first embodiment of a heat exchange system according to the invention with a small passage heat exchanger. FIG. 2 shows a second embodiment according to FIG. 1 with a finned tube heat exchanger. FIG. 5 shows an embodiment with differential pressure measurement to determine pressure loss. FIG. 6 shows pressure loss at various degrees of contamination as a function of the flow rate of the transport fluid. It is a figure which shows the pressure loss and performance curve according to the degree of contamination.

  FIG. 1 shows a schematic diagram of a first embodiment of a heat exchange system with a small passage heat exchanger. The heat exchange system is generally referred to by reference numeral 1 and so on.

The heat exchange system in FIG. 1 includes a heat exchanger 2. In this embodiment, the heat exchanger 2 is a small passage heat exchanger 2 in which a flow path 201 is arranged in the flow segment 21. The transport fluid 3 (in this case a air), for heat exchange between the heat transfer medium 4 flowing through the flow path 210 in the operating state (for example, a refrigerant 4, such as CO _2), the inlet region The transport fluid 3 can be brought into flow contact with the heat exchanger 2 via 201 and directed away from the heat exchanger 2 again via the outlet region 202.

  According to the invention, a contamination sensor 5 is provided for determining contamination of the heat exchanger 2. In this embodiment, the contamination sensor 5 is arranged upstream of the fin pack consisting of the fins 6 in the flow direction of the air 3. The contamination sensor 6 is a pressure sensor 6, a velocity sensor 6, a flow-through sensor 6, or other suitable contamination sensor 6. It can be used to determine a transport parameter TK that is characteristic for the flow of transport fluid from the inlet region 201 through the outlet region 202.

  A fin pack comprising a plurality of fins 6 each having a fin surface 62 serves to increase the heat exchange rate between the flow segment 21 and the transport fluid 3 which in this embodiment is the atmosphere.

  In the embodiment of FIG. 1, louvers may be present, but the louvers are not explicitly shown. Thus, a louver may be provided on the fin 6 in a special embodiment according to FIG. Also, in different embodiments, no louver is provided because no louver is required for appropriate different applications.

  In practice, a fan 7 for transporting air 3 (not shown in FIG. 1 for the sake of clarity) is provided for transporting air 3 by a pack of fins 6. Then, for example, the flow velocity LG according to FIG. 4 can be set according to the contamination intensity of the heat exchanger 2 detected with the help of the contamination sensor 5. In this regard, the transport fluid air 3 is moved from the fan 7 through the pack of fins 6 in the direction of arrow 3.

  FIG. 1 relates to an embodiment according to the invention with a short passage heat exchanger 2. In FIG. 1, a plurality of flow paths 210 which are small passages can be clearly recognized here.

  FIG. 2 is essentially differentiated from the embodiment of FIG. 1 only in that a typical finned tube heat exchanger is used instead of the short path heat exchanger. The louver 61 is clearly seen on the fin 6. In the embodiment of FIG. 2, the fins 6 are not yet contaminated. A further difference from the embodiment of FIG. 1 is that the contamination sensor 5 is housed inside a fin pack consisting of fins 6.

  Needless to say, in each embodiment according to the present invention, another contamination sensor 5 may alternatively be disposed at an appropriate position, or a plurality of contamination sensors 5 may be provided at the same time.

  In a very special arrangement, it is also possible to provide the same heat exchange system with a short-path heat exchanger 2 and a typical finned heat exchanger at the same time.

  Another embodiment, which is actually very important, with a differential pressure measurement for determining the pressure loss ΔP across the heat exchanger 2 is schematically shown in FIG. A fan 7 of a type known per se carries the ambient air 3 having the characteristics of the transport parameter TK through the heat exchanger 2 via the inlet region 201. The fan 7 then guides the air 3 from the heat exchanger system 1 through the outlet area 202 and back through the cover A to the surrounding environment.

  In order to determine the pressure loss ΔP during the passage of the air 3 through the heat exchanger 2, the contamination sensors 5 are respectively provided in front of the inlet region 201 on the left hand side of the drawing and behind the outlet region 202 on the right hand side of the drawing. The pressure loss (ΔP) of the entire heat exchanger 2 can be determined from the measured differential pressure.

  It should be understood that it is not at all limiting to the present invention and that means are used to determine the pressure loss ΔP. Advantageously, various differential pressure sensors known per se can be used in exactly the same way.

  Finally, FIG. 4 schematically shows a typical carpet plot of the characteristics of the transport parameter TK for a heat exchange system 1 having a short passage heat exchanger 2 with fins 6 and louvers 61. .

In the example of FIG. 4, the pressure loss ΔP is shown as a transport parameter TK as a function of the flow velocity LG of the transport fluid 3 at various contamination degrees V (up to V ₀ , V ₁ ,... V _max ). . Those having average skill in the art will have corresponding carpet plots for other transport parameters TK, such as through-flow rates, and of course for other types of heat exchangers, such as finned tube heat exchangers. Can be plotted without problems.

Curve V ₀ is for a heat exchange system 1 that is freshly cleaned, ie not yet contaminated. The characteristic curve V ₁ is recorded after a certain period of operation in the same heat exchange system 1. Here, the heat exchanger 2 is already very contaminated. It can be recognized as a corresponding small pressure loss ΔP. Curve V ₁ is more gradual than curve V _{0 of} uncontaminated heat exchanger 2. After further operation, the heat exchanger 2 is increasingly contaminated, through V ₂ , V _3, etc., eventually showing the maximum allowable contamination in the form of the curve V _max and must be cleaned again. No longer.

  Finally, FIG. 5 is a feature illustrating the relationship between the degree of contamination V and the change in the pressure loss ΔP resulting from this, and the related decrease in the heat transfer performance PW of the heat exchanger 2. A schematic diagram is shown as a schematic diagram.

  The degree of contamination V of the heat exchanger 2 is indicated on the horizontal abscissa. The abscissa increases from left to right in the drawing. The pressure loss ΔP due to the heat exchanger 2 is shown on the left hand axis ΔP on the ordinate. Further, a decrease in the heat transfer performance PW due to the increasing degree of contamination V is simultaneously read on the right hand axis PW of the ordinate.

  In this regard, the solid line ΔP corresponds to the transition of the pressure loss ΔP according to the degree of contamination V, and the dotted line represents a decrease in the heat transfer performance PW according to the degree of contamination V. In this regard, the pressure loss ΔP and the heat transfer performance PW are equally zero at a certain degree of contamination V, ie normalized to 100%, each representing an uncontaminated heat exchanger 2.

With very little contamination V, the pressure drop ΔP across the heat exchanger initially remains nearly constant up to the critical contamination degree Vk. As the degree of contamination increases, the pressure loss ΔP decreases sharply from there and the value of the pressure loss ΔP reaches a minimum value at the degree of contamination V _m . At the same time, the heat transfer performance PW also decreases rapidly. In interval and the previous contamination between Vk and V _m, only first louvers clogged by the particles of dust and thereby transport fluid 3 flowing through the heat exchanger 2, i.e. for example air turbulence 3 is further reduced The louver 61 is more firmly clogged with dust. Thus, the air 3 can pass through the heat exchanger 2 more easily and / or faster. On the one hand, this reduces the pressure loss ΔP, and on the other hand, the effective contact time or effective contact surface between the transport medium 3 and the heat exchanger 2 is reduced, thereby significantly increasing the heat transfer performance PW. A significant decrease is observed.

  When the contamination further increases, the pressure loss ΔP increases again. The reason for this is that the intermediate area between the individual fins, into which the louver is actuated, becomes increasingly clogged with dust, so that air 3 that can be transported through the heat exchanger with the same fan performance per unit time 3 This is because it decreases more and more.

  In this regard, in the vicinity of the minimum value of the pressure loss ΔP, the heat transfer performance PW has already dropped to an unacceptable level, and in this particular embodiment, already 50% of the maximum possible value of the heat transfer performance PW. It is extremely important that it has declined.

  Therefore, a very important recognition of the present invention is that the heat exchanger cleaning should not be done when the pressure loss ΔP increases, but much earlier, ie when the pressure loss ΔP is significantly reduced. That's what it means.

  Thus, according to the invention, maintenance of the cleaning interval can be ensured on the one hand in an ideal way, and on the other hand, the ideal operation of the heat exchange system according to the invention can be ensured. Furthermore, it is possible to use an electronic signal generated semi-automatically for other purposes, and for example, it can be advantageously used for various maintenance purposes.

Claims (15)

A heat exchange system comprising a heat exchanger (2) with a flow path (210) disposed in a flow segment (21), comprising a transport fluid (3) and in the operating state through the flow path (210). For the heat exchange with the flowing heat transfer medium (4), the transport fluid (3) in flow contact with the heat exchanger (2) via the inlet region (201) and the outlet region In a heat exchange system which can be led away from the heat exchanger (2) again via (202),
In order to determine the degree of contamination (V) of the heat exchanger (2), a contamination sensor (5) in the form of a pressure sensor (5) and / or a speed sensor (5) is provided, A heat exchange system characterized in that a transport parameter (TK) specific to the flow of the transport fluid (3) from the inlet region (201) through the outlet region (202) can be determined.   The heat exchange system according to claim 1, wherein the flow segment (21) is provided with fins (6) to increase the heat exchange rate.   3. A heat exchange system according to claim 2, wherein the fins (6) are provided with through-flow openings (61), in particular in the form of louvers (61).   4. The heat exchange system according to claim 1, wherein the at least one heat exchanger (2) is a short passage heat exchanger (2). 5.   The heat exchange system according to any one of claims 1 to 4, wherein the at least one heat exchanger (2) is a tube heat exchanger (2).   6. A transport device (7), in particular a fan, is provided for transport of the transport fluid (3) from the inlet region (201) to the outlet region (202). A heat exchange system according to any one of the above.   The transport parameter (TK) is the pressure of the transport fluid (3), in particular the pressure loss (ΔP) between the inlet region (201) and the outlet region (202) of the heat exchanger (2). The heat exchange system according to any one of claims 1 to 6.   The heat exchange system according to any one of claims 1 to 7, wherein the transport parameter (TK) is a flow rate of the transport fluid (3).   A control unit, in particular a control unit with a data processing unit, can be used for control and / or regulation and / or for collecting data on operating parameters or state parameters of the heat exchange system. 9. The sensor and / or the transport device (7) and / or the contamination sensor (5) and / or a heat engine as a signal connection. Heat exchange system.   Said heat exchange system is a radiator, in particular a radiator for an automobile, in particular a land vehicle, an aircraft or a water vehicle, or a portable or stationary heating facility, cooling facility or air conditioning facility, in particular a machine or building for a data processing system The heat exchange system according to any one of claims 1 to 9, wherein the heat exchange system is a radiator, condenser or vaporizer for a cooling device.   A method for operating a heat exchange system (1) according to any one of claims 1 to 10, wherein a transport parameter (TK) is measured and a heat exchanger is determined from the transport parameter (TK). (2) A method for determining the degree of contamination (V).   12. The method according to claim 11, wherein the pressure drop ([Delta] P) is determined from the transport parameter (TK).   The method according to claim 11 or 12, wherein a decrease in the heat transfer performance (PW) of the pressure of the heat exchanger (2) is determined from the pressure loss (ΔP).   The performance of the transport device (7), in particular the rotational speed of the fan (7), is controlled and / or adjusted according to the degree of contamination of the heat exchanger (2) and / or for service routines. 14. A method according to any one of claims 11 to 13, wherein the timing is automatically determined according to the degree of contamination.   In an on-line method, operating data and / or status data from the heat exchange system (1) is monitored by a control center and / or the heat exchange system (1) is controlled and regulated, especially via an intranet or the Internet. 15. A method as claimed in any one of claims 11 to 14, wherein:

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