EP1520146A1

EP1520146A1 - Heat exchanger

Info

Publication number: EP1520146A1
Application number: EP03740407A
Authority: EP
Inventors: Walter Demuth; Martin Kotsch; Karl-Heinz Staffa; Christoph Watler
Original assignee: Behr GmbH and Co KG
Current assignee: Mahle Behr GmbH and Co KG
Priority date: 2002-07-03
Filing date: 2003-07-03
Publication date: 2005-04-06
Also published as: ZA200402528B; CN1592839A; US20050006072A1; AU2003281285A1; US7650934B2; WO2004005826A1; JP2005531748A; DE10229973A1; CN100374807C; BR0305261A

Abstract

The invention relates to a heat exchanger, particularly a radiator for a heating or air conditioning unit in motor vehicles, which cools a coolant. Said heat exchanger (1) is penetrated by air, comprises collector pipes (S1, S2, S3, S4) and several essentially horizontally disposed pipes (5), and is divided into several partial blocks (T1, T2, T3, T4). The surfaces of the inventive partial blocks are selected according to the dimensions of structural space-related zones having different air temperatures inside the assembly space of the heat exchanger, the partial block which is first penetrated by the coolant being arranged within a structural space-related zone having a higher air temperature, preferably within the zone having the highest air temperature.

Description

BEHR GmbH & Co.Mauserstraße 3, 70469 Stuttgart

Heat exchanger

The invention relates to a heat exchanger, in particular a cooler for a heating or air conditioning system of motor vehicles, according to the preamble of claim 1, 8, 9, 10 or 11.

From EP 0 845 648 A2 a flat tube heat exchanger is known, in particular a serpentine type condenser, with a flat tube block consisting of one or more flat tubes, which with preferably twisted end sections on the opposite or on the same tube block side in respective connection space components, i.e. Manifolds, so that if the manifolds are arranged on the same tube block side, two adjacent and parallel manifolds are provided. A plurality of serpentine-shaped flat tubes can be provided, in which adjacent flat tubes are arranged adjacent to one another in the longitudinal direction of the header tubes with their inlet-side or outlet-side tube sections, the serpentines comprising a plurality of 180 ° bends. A corresponding arrangement prevents heat transfer losses, but still leaves something to be desired.

EP 0 414 433 discloses a duplex heat exchanger which enables a refrigerant flow in cross-countercurrent by two flat heat exchangers arranged in series, hereinafter referred to as blocks, each with two header pipes, which are connected over a large number of flat tubes. tubes are interconnected, are provided. The two blocks are connected to each other by means of flanges and O-ring seals, for which purpose they have to be assembled, tensioned, soldered and connected after soldering. The refrigerant is supplied to the block through which flow first occurs in an upper region, the outlet at the bottom, and when the second block flows through thereafter, the inlet can take place both at the bottom and at the top, and the outlet takes place accordingly at the top and bottom. Such a duplex heat exchanger consisting of two blocks is associated with a large number of individual parts and a relatively high production outlay, so that production is expensive. Such a heat exchanger also leaves something to be desired with regard to the thermal properties.

Furthermore, from DE 100 43 439 A1 a cooler for a supercritical vapor compression refrigeration cycle is known, in which a refrigerant outlet is provided in a higher position than a refrigerant inlet in relation to a vertical direction, so that refrigerant flows from an underside to an upper side of the cooler. which promises an improvement in the cooling efficiency of the refrigerant. However, such a cooler also leaves something to be desired in terms of coolant efficiency.

It is an object of the invention to improve a heat exchanger of the type mentioned.

This object is achieved by a heat exchanger with the features of claim 1, 8, 9, 10 or 11. The dependent claims relate to advantageous developments and further developments of the invention.

The main idea of the invention is the surfaces of the

Make sub-blocks dependent on the size of installation space-related zones with different air temperatures and first let refrigerant flow through the sub-block within a construction space-dependent zone, with the sub-block preferably being arranged within the zone with the highest air temperature. In an advantageous embodiment of the heat exchanger, the height of the partial block through which refrigerant flows is at least as large as the height of the zone with increased air temperature.

In a further advantageous embodiment of the heat exchanger, the number of pipes arranged in a partial block in the horizontal direction depends on the space temperature-related air temperature zone within which the corresponding partial block is arranged.

In a particularly advantageous embodiment of the invention, the number of tubes of a partial block within a zone with a higher temperature is greater than the number of tubes of a partial block which is arranged within a zone with a lower temperature, the ratio of the number of tubes of the partial block within the zone also a higher temperature for the number of tubes of the sub-block within the zone with a lower temperature in the range from 1: 1 to 3: 1 can be selected.

In a particularly advantageous embodiment of the invention, at least two sub-blocks are arranged one behind the other and at least two sub-blocks one above the other, the sub-blocks being flowed through one after the other by the refrigerant, and the sequence of the through-flow being arbitrarily specifiable by means of structural measures.

The refrigerant preferably flows through at least two of the sub-blocks in countercurrent to the air flow.

In a particularly advantageous embodiment, the heat exchanger is subdivided into four sub-blocks, which are flowed through in succession, the sub-blocks flowing through first being arranged below the sub-blocks flowed through subsequently, the first and second sub-blocks as well as the third and fourth sub-blocks each being at the same height are arranged. Such a heat exchanger is particularly suitable for an installation space in which, due to the installation space, a zone in a lower area a higher air temperature is present than in an upper area of the installation space.

In an alternative embodiment of the heat exchanger, the partial blocks flowed through first are arranged above the partial blocks flowed through subsequently, the first and second partial blocks and the third and fourth partial blocks each being arranged at the same height. This alternative embodiment of the heat exchanger is particularly suitable for an installation space in which, due to the installation space, a zone with a higher air temperature is present in an upper region than in a lower region of the installation space.

Depending on the zones with different temperatures, the temperature of the refrigerant differs in the different sub-blocks. Thus, in one embodiment of the heat exchanger, which is arranged in an installation space in which a zone with a higher air temperature is present in a lower region than in an upper region of the installation space, the temperature of the refrigerant in the lower sub-blocks is higher than in the upper ones Sub-blocks, where the temperature of one or both rear sub-blocks is higher than the temperature of the corresponding front

Is partial block. In an alternative embodiment of the heat exchanger, which is arranged in an installation space in which there is a zone with a higher air temperature in an upper region than in a lower region of the installation space, the temperature of the refrigerant is higher in the upper sub-blocks than in the lower ones Sub-blocks, the temperature of one or both rear sub-blocks being higher than the temperature of the corresponding front sub-block.

In all the cases mentioned, R 134 a and carbon dioxide, for example, can be used as refrigerants. In particular, carbon dioxide in a supercritical state, ie if there is a pure gas flow in the heat exchanger, is suitable for a heat exchanger according to the invention. A flow of at least two of the four sub-blocks with refrigerant preferably takes place in a cross-countercurrent to the air. Cross-countercurrent operation results in more effective heat transfer.

In particular, a diagonal deflection is provided between the second sub-block and the third sub-block, so that cross-countercurrent operation takes place in all sub-blocks.

The diagonal deflection is preferably formed by means of a one-piece transition flange which is connected to two manifolds, namely to the manifold assigned to the second sub-block and to the third sub-block.

A tube, in particular a flat tube, is preferably provided in the region of the diagonal deflection, through which refrigerant does not flow or only flows minimally, whereby the heat transfer is decoupled.

The tubes connecting the collecting tubes in the area where the heat transfer takes place are preferably formed by flat tubes, the flat tubes being twisted in the vicinity of the collecting tubes and on the side of the heat exchanger opposite the collecting tubes before and after a 180 ° bending point by 90 °.

In a further embodiment, the sub-blocks are closed on both sides by manifolds, wherein at least two sub-areas on at least one side can also be terminated by a common manifold.

The air flowing through the heat exchanger preferably comes into contact with two or more areas with different temperatures, the maximum air temperature difference between the air inlet and outlet being less than half the temperature difference between the refrigerant inlet and the refrigerant outlet, carbon dioxide being used as the refrigerant in supercritical operation , Temperatures are around 150 ° C at the refrigerant inlet and around 50 ° C at the outlet. The tubes arranged essentially in the horizontal direction are preferably thermally separated from one another, for example by an air gap.

The individual partial blocks are preferably also thermally separated from one another.

The header tubes are preferably also essentially thermally decoupled. There is only thermal contact on the diagonal deflection and, depending on the version, also on the connecting flanges.

The cooling fins arranged between the tubes are preferably also thermally decoupled. This is achieved, for example, in that each sub-block has its own cooling fins.

The invention is explained in detail below using an exemplary embodiment with reference to the drawing. The drawing shows:

Figure 1 is a front view of a flat tube heat exchanger according to the embodiment.

FIG. 2 shows a section through the flat tube heat exchanger from FIG. 1 along line II-II in FIG. 1;

3 to 6 a transition flange in different views; and

7 to 9 a connector in different views.

Figures 1 and 2 show a cooler 1 serving as a flat tube heat exchanger for a heating or air conditioning system of a motor vehicle, which is part of a refrigerant circuit, not shown, and is used to pass a refrigerant, in particular CO ₂ , with the aid of which the cooler 1 flows Cool air. In Fig. 2 the air flow is symbolic by one of shown on the left on the radiator 1 arrow. In supercritical operation, the CO ₂ is usually present as a pure gas flow, temperatures of around 150 ° C. being present at inlet 2 in cooler 1. The coolant is cooled in the cooler 1, so that there are 3 temperatures at 50 ° C. at the outlet.

In order to enable optimal use of the air flowing through the cooler 1, the cooler 1 is divided into 2 × 2 sub-blocks, which are referred to below as T1, T2, T3 and T4. The sub-blocks T1 and T2 are arranged in the installed state within a zone 4 with a higher air temperature and below the sub-blocks T3 and T4. The height h of the two sub-blocks T1, T2, which are arranged within zone 4 with the higher air temperature, is greater than the height H of zone 4 with increased air temperature, the value of the air temperature in zone 4 being greater than the air temperature in the remaining areas of the installation space of the cooler 1. A manifold S1, S2, S3, S4 is connected to each sub-block, two manifolds S1, S2 and S3, S4 being arranged at the corresponding height of the sub-blocks T1, T2 or T3, T4 are. A plurality of flat pipes 5 are arranged between the collecting pipes S1 and S2 as well as S3 and S4, through which the refrigerant can pass from a collecting pipe S1 or S3 to the neighboring collecting pipe S2 or S4, which is why the flat pipes 5 have a U-shaped course. They are twisted by 90 ° in a known manner in the vicinity of the respective manifold S1, S2, S3, S4. Ribs (not shown) are arranged between the flat tubes 5, which support the heat exchange. These ribs can be divided into two, ie. H. the sub-blocks T1 and T2 or T3 and T4 arranged one behind the other each have their own ribs. However, it is also possible to thermally decouple the ribs of the partial blocks by means of slots.

So that the cooler 1 can be flowed through in a cross-counterflow to the air, a diagonal reversal 6 from partial block T2 to partial block T3 is provided, as indicated in FIG. 2 by an arrow drawn in the cooler 1. For this purpose, a transition flange 7, as shown in FIGS. 3 to 6, is provided between the two manifolds S2 and S3, the zone of the flat tube 5 ', which lies on the boundary of the two sub-blocks T2, T3, is used by the partitions of the two collecting pipes S2 and S3 are offset by a transverse division. The middle flat tube 5 'is thus "short-circuited" and hardly flows through, at most as a result of a small pressure difference that occurs between the two header tubes S2 and S3 due to the low throttling effect in the transition flange 7. The flat tube 5' which has no or only minimal flow has the As a side effect, thermal decoupling is achieved between the sub-blocks T1 and T3 or T2 and T4 The transition flange 7 is usually designed as a component together with the two partition walls and is soldered when the cooler 1 is soldered.

The manifolds S1 and S2 or S3 and S4 are connected to each other at inlet 2 and outlet 3 via a connector 9, as shown in FIGS. 7 to 9, so that refrigerant can also get directly into manifold S2 can flow directly out of the collecting pipe S3.

For thermal decoupling, the refrigerant is collected after the partial blocks T1 and T2 or T3 and T4 have been flowed through, in separately formed collecting pipes S1, S3 or S2, S4. The thermal coupling of the sub-blocks T1 and T2 or T3 and T4 via the one-piece ribs can be reduced by slitting the rib or by any other suitable measure.

According to the exemplary embodiment shown, the sub-blocks T1, T2 are divided into sub-blocks T3, T4 50:50, but the division should preferably be degressive, i.e. for example, 60:40 or 70:30, because, as with the condenser, the outlet density is higher and thus the volume flow is lower than at the inlet. In addition, the gas cooler also serves as a capacitor in subcritical operation.

.o0o. LIST OF REFERENCE NUMBERS

1 cooler

2 inlet

3 outlet

4 zone with higher temperature 5, 5 'flat tube

6 diagonal reversal

7 transition flange 9 connecting piece

S1, S2, S3, S4 manifold T1, T2, T3, T4 partial block H height of the zone with higher temperature h partial block height

Claims

Patent claims

1. Heat exchanger, in particular cooler for a heating or air conditioning system of motor vehicles for cooling refrigerant through which air flows, with manifolds (S1, S2, S3, S4) and a plurality of tubes (5) arranged essentially in the horizontal direction, wherein the heat exchanger (1) is divided into several sub-blocks (T1, T2, T3, T4), characterized in that the surfaces of the

Sub-blocks are dependent on the size of installation space-related zones with different air temperatures in the installation space of the heat exchanger, the sub-block through which refrigerant flows first being arranged within an installation space-related zone with a higher air temperature, preferably within the zone with the highest air temperature.

2. Heat exchanger according to claim 1, characterized in that the height of the partial block first flowed through by refrigerant is at least as large as the height of the zone with increased air temperature.

3. Heat exchanger according to claim 1 or 2, characterized in that the number of tubes arranged in a partial block in the horizontal direction is dependent on the space temperature-related air temperature zone within which the corresponding partial block is arranged.

4. Heat exchanger according to claim 3, characterized in that the number of tubes in a first sub-block, which is arranged within a zone with a higher temperature, is greater than that Number of tubes of a second sub-block, which is arranged within a zone with a lower temperature.

5. Heat exchanger according to claim 3 or 4, characterized in that the ratio of the number of tubes of the first sub-block to

The number of tubes in the second block can be selected in the range from 1: 1 to 3: 1.

6. Heat exchanger according to one of the preceding claims, characterized in that at least two sub-blocks are arranged one behind the other and at least two sub-blocks one above the other, wherein the sub-blocks are flowed through in succession by the refrigerant, and the sequence of the flow can be predetermined by means of structural measures.

7. Heat exchanger according to claim 6, characterized in that at least two of the partial blocks are flowed through by the refrigerant in counterflow to the air flow.

8. Heat exchanger, in particular cooler for a heating or air conditioning system of motor vehicles for cooling refrigerant through which air flows, with manifolds (S1, S2, S3, S4) and a plurality of tubes (5) arranged essentially in the horizontal direction, wherein the heat exchanger (1) is subdivided into four sub-blocks (T1, T2, T3, T4) which are flowed through one after the other, characterized in that the sub-blocks (T1, T2) through which flow flows first are arranged below the sub-blocks (T3, T4) subsequently flowed through , the first and second sub-blocks (T1 and T2) and the third and fourth sub-blocks (T3 and T4) each being arranged at the same height.

9. Heat exchangers, in particular coolers for a heating or air conditioning system of motor vehicles for cooling refrigerant through which air flows, with manifolds (S1, S2, S3, S4) and a plurality of tubes arranged essentially in the horizontal direction (5), the heat exchanger (1) being subdivided into four sub-blocks (T1, T2, T3, T4), which are flowed through in succession, characterized in that the sub-blocks (T3, T4) through which flow passes above the sub-blocks (T1 , T2) are arranged, the first and second sub-blocks (T1 and T2) and the third and fourth sub-blocks (T3 and T4) each being arranged at the same height.

10. Heat exchanger, in particular cooler for a heating or air-conditioning system of motor vehicles for cooling refrigerant, by

Air flows through, with manifolds (S1, S2, S3, S4) and a plurality of tubes (5) arranged essentially in the horizontal direction, the heat exchanger (1) being divided into four sub-blocks (T1, T2, T3, T4) which are flowed through in succession, characterized in that the temperature of the refrigerant in the lower sub-blocks

(T1, T2) is higher than in upper sub-blocks (T3, T4), the temperature of one or both rear sub-blocks (T1, T3) being higher than the temperature of the corresponding front sub-block (T2, T4).

11. Heat exchanger, in particular cooler for a heating or air conditioning system of motor vehicles for cooling refrigerant through which air flows, with manifolds (S1, S2, S3, S4) and a plurality of tubes (5) arranged essentially in the horizontal direction, wherein the heat exchanger (1) is divided into four sub-blocks (T1, T2, T3, T4) which are flowed through in succession, characterized in that the temperature of the refrigerant in the upper sub-blocks (T3, T4) is higher than in the lower sub-blocks (T1, T2 ), the temperature of one or both rear sub-blocks (T1, T3). is higher than the temperature of the corresponding front sub-block (T2, T4).

12. Heat exchanger according to one of the preceding claims, characterized in that at least two of the four sub-blocks (T1, T2, T3, T4) can be flowed through in cross-counterflow to the air.

13. Heat exchanger according to one of the preceding claims, characterized in that a diagonal deflection (6) is provided between two sub-blocks (T2, T3).

14. Heat exchanger according to claim 13, characterized in that the diagonal deflection (6) takes place by means of a one-piece transition flange (7) which is connected to two header pipes (S2, S3).

15. Heat exchanger according to claim 14, characterized in that the transition flange (7) has partition walls for the header pipes (S2, S3).

16. Heat exchanger according to claim 15, characterized in that the transition flange (7) has two mutually parallel, spaced-apart cylindrical recesses.

17. Heat exchanger according to claim 15 or 16, characterized in that the transition flange (7) has a passage which forms a connection between the two manifolds (S2 and S3).

18. Heat exchanger according to one of claims 13 to 17, characterized in that in the region of the diagonal deflection (6) at least one tube (5 ') is provided which is not or only slightly flowed through by refrigerant.

19. Heat exchanger according to one of the preceding claims, characterized in that a connection piece (9) is provided at the inlet (2) and / or at the outlet (3), which has two manifolds

(S1 and S2 or S3 and S4) is connected.

20. Heat exchanger according to claim 19, characterized in that the connecting piece (9) has a partition.

21. Heat exchanger according to claim 20, characterized in that the connecting piece (9), the partition wall is formed by the remaining material section of two parallel cylindrical recesses.

22. The heat exchanger as claimed in claim 21, characterized in that the connecting piece (9) has a cylindrical recess which runs perpendicularly to the partition and partially penetrates the partition and forms the inlet or outlet.

23. Heat exchanger according to one of the preceding claims, characterized in that the flat tubes (5) in the vicinity of the header tubes (S1, S2, S3, S4) are twisted by 90 ° in each case.

24. The heat exchanger according to claim 23, characterized in that the flat tubes (5) on the side of the heat exchanger (1) opposite the collecting tubes (S1, S2, S3, S4) are twisted by 90 ° before and after a 180 ° bending point.

25. Heat exchanger according to one of the preceding claims, characterized in that the partial areas (T1, T2, T3, T4) are closed on both sides by manifolds (S1, S2, S3, S4).

26. Heat exchanger according to claim 25, characterized in that at least two partial areas (T1, T2, T3, T4) on at least one

Side are completed by a common manifold (S1, S2, S3, S4).

27. Heat exchanger according to one of the preceding claims, characterized in that the air flowing through the heat exchanger (1) comes into contact with two or more areas with different temperatures, the maximum air temperature difference between air inlet and outlet being less than one and a half times the temperature difference between the refrigerant inlet and outlet, carbon dioxide being used as the refrigerant in supercritical operation.

28. Heat exchanger according to one of the preceding claims, characterized in that the tubes (5) arranged essentially in the horizontal direction are thermally separated from one another.

29. Heat exchanger according to one of the preceding claims, characterized in that the individual sub-blocks are thermally separated from one another.

30. Heat exchanger according to one of the preceding claims, characterized in that the header pipes are essentially thermally decoupled.

31. Heat exchanger according to one of the preceding claims, characterized in that cooling fins are arranged between the tubes (5) arranged essentially in the horizontal direction, the cooling fins of the individual sub-blocks, in particular of the sub-blocks, which are located one behind the other, being thermally decoupled.