The invention relates to a heat exchanger, in particular a condenser or gas cooler for air conditioning systems, in particular for motor vehicles, preferably according to the preamble of patent claim 1.
Condensers have become known from EP-B 0 414 433, in which two condensers are arranged one behind the other on the air side and are connected mechanically to one another by means of additional fastening elements. On the refrigerant side, the flow passes through the two condensers either in series or in parallel. In the case of the series connection, heat exchange takes place in cross countercurrent, that is to say the flow passes first through the leeward-side condenser, and the refrigerant then passes via a connecting line over into the windward-side condenser and flows through the latter as far as the refrigerant outlet located on the windward side. The two condensers have the flow passing through them in a multiflow manner with a decreasing flow cross section (degressive connection). A deflection of the refrigerant therefore takes place only within the plane of each condenser, that is to say only in width. This known duplex condenser has the disadvantage that two condensers have to be connected to one another both mechanically and on the refrigerant side, thus necessitating additional components and assembly time. This means increased production costs. Furthermore, the known condenser also has thermodynamic potentials, since the flow does not pass through it optimally.
The object of the present invention is to improve a heat exchanger, in particular gas cooler or condenser, of the type initially mentioned, to the effect that, while the end face remains the same, the power output is increased and/or the weight and/or production costs are reduced.
The solution for achieving this object arises from the features of patent claim 1.
The heat exchanger according to the invention, such as, in particular, condenser or gas cooler, is preferably produced as a materially integral block which is preferably soldered “in one shot”. Consequently, mechanical connection parts are dispensed with, and production costs are lowered. Furthermore, the condenser is divided in the plane or in the planes of the flow ducts, that is to say in width, into blocks and/or perpendicularly to the planes, that is to say in depth, into segments through which the flow passes in succession, both a deflection in depth or in width and a deflection in depth and in width taking place. Owing to this division of the two-row condenser network, optimum throughflow possibilities arise on the refrigerant side, thus resulting in an increase in the power output of the condenser.
Advantageous refinements of the inventions may be gathered from the subclaims.
Advantageously, there is an even number of segments, since each block consists of two segments with an equal number of flow ducts. Advantageously, however, there may also be an odd number of segments, to be precise when one segment (or else a plurality) is subdivided into subsegments through which the refrigerant flows in succession. The throughflow possibilities of the condenser are thereby further extended, thus allowing additional increases in power output. It is advantageous, furthermore, if the refrigerant inlet is arranged on a leeward-side or windward-side segment and the refrigerant outlet is arranged on a windward-side or leeward-side segment.
According to an advantageous refinement of the invention, the flow passes through the individual segments in succession, in such a way that a deflection of the refrigerant in depth and in width takes place alternately. This gives rise to a cross counter/cocurrent for heat exchange between air and refrigerant.
According to a further advantageous variant of the invention, after a deflection in depth, a simultaneous deflection in depth and in width takes place. This gives rise, for heat exchange between air and refrigerant, to a cross countercurrent which entails further thermodynamic advantages.
According to an advantageous refinement of the invention, the flow ducts are designed as flat tubes, specifically either in two, three or more rows or in one row, the “continuous” flat tube having the flow passing through it in a two-flow, three-flow or multiflow manner. The flat tubes in this case have, if appropriate, inner ducts which are arranged in parallel and through which the flow passes in parallel. These ducts may also have connecting orifices with respect to one another. These flat tubes may also have turbulence inserts which are introduced into the flat tube.
Furthermore, it is advantageous if the flat tube ends are fastened in a manifold which is common to more than one flat tube and in which the deflection in depth takes place. Furthermore, in an advantageous solution, the flat tube ends issue on the other side into two manifolds in which the deflection in width takes place. In this case, it is advantageous if the two manifolds either are produced in one piece and consequently hold the block together or are produced as separate manifolds which are held together via the “continuous” flat tubes. Advantageously, the flat tubes have arranged between them continuous corrugated ribs which, by being soldered to the flat tubes, ensure a compact and inherently stable condenser block.
According to a further advantageous refinement of the invention, additional deflection members between the manifolds are provided, by means of which a simultaneous deflection of the refrigerant both in depth and in width becomes possible. By means of these deflection members, for example tube bends, segments through which the flow is capable of passing in series are connected to one another on the refrigerant side. These deflection members may be soldered into the manifolds, so that this variant of the condenser according to the invention can also be soldered in one operation in the soldering furnace.
Exemplary embodiments of the invention are illustrated in the drawing and are described in more detail below. In the drawing:
The rib height of the corrugated ribs, that is to say the distance between two flat tubes in a row, is advantageously 4 mm to 12 mm. The rib density, that is to say the number of ribs per decimeter, is advantageously in the range of 45 to 95 ribs/dm, which corresponds to a rib spacing or a rib division of 1.05 to 2.33 mm. The rib or corrugated rib may advantageously be inserted from a strip, in which the strip is inserted in corrugations or in zigzag form between the flat tubes. Expediently, the rib thus configured will have thermal separation between different regions, so that the regions which are arranged between different flat tubes or flat tube regions are at least partially insulated thermally.
In a further advantageous embodiment, the rib may also consist of a plurality of individual strips which are inserted between the adjacent flat tubes. It is advantageous, in this case, that the individual ribs of different rows have no thermal connection.
The flat tubes are advantageously configured in such a way that the tube width, that is to say the extent of the tubes in the direction of an adjacent tube of the same planes, is in the range of 1 mm to 5 mm, in particular advantageously of 1.2 mm to 3 mm. The extent of the tubes between the direction perpendicular to the planes, the tube depth, is expediently in the range of 3 mm to 20 mm, advantageously in the range of 5 mm to 10 mm.
In one exemplary embodiment of the invention, the tube depth may be essentially identical in the blocks of the heat exchanger. In another exemplary embodiment of the invention, however, the selected tube depth may also be different from block to block. It is particularly expedient if the tube depth in the windward-side plane is smaller than the tube depth in the leeward-side plane.
In the heat exchangers illustrated in the figures, the tubes of different planes are arranged in alignment in series, as seen in the airflow direction, that is to say they are arranged in series of the same height.
In heat exchangers that are not illustrated, the tubes of one plane may be arranged so as to be offset with respect to the tubes of a further plane. This offset arrangement may preferably take place up to the height of half the rib height plus half the tube width. Intermediate values may also be assumed. In such an exemplary embodiment, different or identical ribs, which are advantageously produced as independent strips, may be used between the tubes of various planes.
The flat tubes 4 of the two rows 2, 3 have flat tube ends 4a which issue into a common manifold 5. On the other side, the flat tubes 4 of the two rows 2, 3 have flat tube ends 4b which issue into two separate manifolds 6, 7. The manifold 7 is a refrigerant inlet 8. The two manifolds 6, 7 are subdivided into manifold sections by means of partitions, of which a partition 9 is illustrated only in the manifold 6 which is illustrated as being open. The air flows through the condenser in the direction of the arrow L, the airflow direction. The flow profile of the refrigerant in the condenser 1 is illustrated by a multiply angled line beginning with the refrigerant inlet KME and ending with the refrigerant outlet KMA. As is explained in more detail later, the two rows 2, 3 of the flat tubes 4 are subdivided into three blocks I, II, III, each block being subdivided in each case into two segments Ia, Ib; IIa, IIb and IIIa, IIIb. The refrigerant therefore flows first through the leeward-side segment Ia of the rear tube row 3, then passes into the manifold 5, where it is deflected in depth, illustrated by the arrow UT1, and then passes into the windward-side segment Ib and into the windward-side manifold 6, where it is deflected in width, illustrated by the arrow UB1. The refrigerant then flows through the next segment IIa back again into the manifold 5, where it is deflected once more in depth, but in the opposite direction to previously, according to the arrow UT2. It flows thereafter through the leeward-side segment IIb into the leeward-side manifold 7, is deflected there once more in width, illustrated by the arrow UB2, flows again through a further segment IIIa into the manifold 5, is again deflected there in depth, illustrated by the arrow UT3, and finally flows through a last windward-side segment IIIb to the refrigerant outlet KMA. As a result of this throughflow of refrigerant, on the one hand, and of air, on the other hand, a cross counter/cocurrent is obtained, specifically because, on the one hand, the refrigerant and the air run in cross current and, on the other hand, the deflections in depth UT1, UT3 run opposite to the airflow direction L and the deflection in depth UT2 runs in the airflow direction.
When the division of a segment into subsegments is employed, a partition is advantageously used in the manifold. This partition may expediently be designed as a separating plate.
All the variants described above (flow patterns with a degressive connection) achieves the largest power output when the ratio of the refrigerant outlet cross section to the refrigerant inlet cross section is in the range of 0.25 to 0.40. This ratio corresponds to the number ni of flat tubes of the last throughflow segment to the number n1 of flat tubes of the first throughflow segment (presupposing identical flat tube cross sections).
According to a further inventive idea, the flow can pass through the heat exchanger from the top downward or from the bottom upward. Bottom and top are defined by the installation position of the heat exchanger. Also, for example, a flow can pass through one plane of the heat exchanger from the bottom upward and through another plane from the top downward. In this case, the flow ducts are preferably arranged horizontally.
In a further advantageous exemplary embodiment, the flow ducts are expediently oriented vertically and the manifolds are oriented horizontally.
Number | Date | Country | Kind |
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102 57 767.6 | Dec 2002 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP03/12224 | 11/3/2003 | WO | 1/4/2005 |