EP1382926B1 - Evaporator for vehicles air conditioning devices - Google Patents

Description

The invention relates to an evaporator of an air conditioner for a motor vehicle according to claim 1. The usual today evaporator such as disc evaporator and flat tube evaporator are installed vertically in the air conditioner or the vehicle, ie with vertical tubes. Common flat tube evaporator, z. B. known by the DE-A 198 26 881 the applicant, are formed in two rows, ie with two rows of flat tubes, which are successively or successively flowed around by air. The ends of the headers open into headers, which are each divided into two chambers which receive the ends of the flat tubes. The refrigerant is deflected once in the depth, that is opposite to the direction of air flow in double-flow. Such flat tube evaporators have a height H, measured in the longitudinal direction of the tubes, and a width B, measured transversely to the tube longitudinal direction. The product of height H and width B gives the face of the evaporator. The refrigerant can - in addition to the deflection in the depth - be deflected in width. This evaporator design is known to have a height to width ratio of about 0.5 to 2.0, that is, for the lowest evaporators of this type, the height is about half the width.

The document US 4679410 discloses the features of the preamble of claim 1. Similar dimension ratios of height to width are in the disk evaporators, such as by the EP-A 1 089 046 known. In this design, the flow channels for the refrigerant and the collection chambers are integrated into disc halves, which are soldered together. These disk evaporators are also installed with vertical flow channels.

A technical problem arises when you want to further reduce the ratio of evaporator height to evaporator width due to certain installation requirements of the vehicle manufacturer, d. H. Evaporator low height and relatively large width needed. The proportion of collection boxes on the face would reduce this disproportionately. In order to obtain a uniform temperature distribution at the air outlet of such an evaporator, the refrigerant would have to be deflected several times in width, which would lead to considerable refrigerant side pressure loss. Therefore, this design limits are set with respect to the reduction of the evaporator height at about the same end face. The same applies in principle for the disk evaporator.

It is an object of the present invention to provide an evaporator of the type mentioned, which has a lower overall height with the same end face and the same power, if possible at a favorable temperature profile.

The invention provides a horizontal evaporator, in which the flow channels are arranged approximately horizontally in the installation position and the lateral collecting chambers are arranged approximately vertically or flowed through. Vertical, however, does not mean strictly vertical, since the evaporators in air conditioners are sometimes arranged slightly inclined. Such an arrangement should also be encompassed by the term approximately vertically. By this construction, a ratio of height to width in the range of 1: 3 to 1: 6 or a ratio of width to height in the range of about 3 to 6 and more, that is advantageously up to 7, 8, 9m or 10 or more can be realized without the performance of the evaporator decreases. Opposite the Construction with vertical flow channels even results in a performance gain. Furthermore, the advantage of a smaller number of parts over the known construction with vertical flow channels, since the inventive evaporator longer, but has fewer tubes or flow channels. This reduces the manufacturing costs.

According to an advantageous embodiment of the invention, the evaporator is designed as a disk or flat tube evaporator, wherein the flat tube evaporator proves to be particularly advantageous. It can in principle be built with almost the same or similar components as the aforementioned prior art of the applicant - but in a horizontal design with correspondingly low height and large width. By arranging partition walls in the collecting tanks, a double or multiple flooding with deflection of the refrigerant in the depth and the height can be made possible, which causes a favorable temperature distribution for the exiting air from the evaporator.

In a further advantageous embodiment of the invention, the injection of the refrigerant takes place in the underlying tubes or in the underlying of the collection chamber. Advantageously, the refrigerant is then aspirated in the upper region in the vaporous or superheated state. This makes it possible to operate the evaporator according to the invention also with a conventional expansion valve.

According to an advantageous embodiment of the invention, the inlet and outlet openings can both be arranged at the bottom of a collection box, then the overflow openings for the deflection of the refrigerant in the depth in the upper region of the vertical partition. This prevents liquid refrigerant from being sucked out.

In an advantageous embodiment of the invention, the inlet and outlet openings can both be arranged at the top of a collecting box, then the overflow openings for the deflection of the refrigerant in the depth in the lower region of the vertical partition. This ensures that only vaporous refrigerant is sucked out.

According to the invention, the evaporator on side parts, wherein the lower side part has recesses for the condensate drain. Since the flat tubes are horizontal, the condensation forming in humid air is carried along by the air flow. Between the rows of flat tubes, it can - following the principle of gravity - drip down and drain through the recesses. This avoids unpleasant evaporator odor. In addition, spray water grids for collecting the sprayed condensed water can be arranged on the air outlet end region of the evaporator.

It may be advantageous that viewed over the length of the side part, at least one or more recesses are provided, such as a plurality of elongated recesses. It may be expedient if the recesses are arranged in the side part substantially on the down or on the outflow side. In another embodiment, it may also be expedient if the recess / the recesses lie on the inflow side or at least partially over both regions, that is to say outflow side or inlet or inflow side.

Fig. 1

einen liegenden Verdampfer in zweiflutiger Durchströmung in Flachrohrbauweise in einer Ansicht von unten,

Fig. 1a

den Verdampfer gemäß Fig. 1 in einer Ansicht von vorne,

Fig. 1b

den Verdampfer gemäß Fig. 1 in einer Seitenansicht,

Fig. 1c

ein Ausführungsbeispiel eines Verdampfers in einer Ansicht von unten,

Fig. 2

ein zweites Ausführungsbeispiel eines liegenden Verdampfers mit zweifacher Durchflutung in schematischer Darstellung,

Fig. 3

ein Diagramm zum Leistungsvergleich der erfindungsgemäßen und der herkömmlichen Bauweise,

Fig.4

ein Diagramm zum Vergleich der erfindungsgemäßen und der herkömmlichen Bauweise im Hinblick auf den spezifischen Nutzraum und

Fig. 5

ein Diagramm zum Vergleich der erfindungsgemäßen und der herkömmlichen Bauweise im Hinblick auf den luftseitigen Druckabfall.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below. Show it

Fig. 1

a lying evaporator in double flow in flat tube construction in a view from below,

Fig. 1a

the evaporator according to Fig. 1 in a view from the front,

Fig. 1b

the evaporator according to Fig. 1 in a side view,

Fig. 1c

an embodiment of an evaporator in a view from below,

Fig. 2

a second embodiment of a horizontal double-flow evaporator in schematic representation,

Fig. 3

a diagram for comparing the performance of the inventive and the conventional construction,

Figure 4

a diagram for comparing the inventive and the conventional construction with respect to the specific usable space and

Fig. 5

a diagram for comparing the inventive and the conventional construction with respect to the air side pressure drop.

Fig. 1, 1st A and 1 b show a double-row, double-flow flowed through flat-tube evaporator 1 in a horizontal installation position, that is with lying flat tubes, in a view from below. The air flow direction is indicated by the arrow L.

Fig. 1a shows the evaporator 1 with respect to its end face, which is defined by the height H and the width B. The front side of the evaporator 1 shows a total of ten flat tubes 2, between which corrugated fins 3 are arranged. The flat tubes 2 open on both sides in collecting tanks 4, 5, which are each divided by a longitudinal partition wall 6 into two chambers 7, 8 (the subdivision of the chamber 5 is in Fig. 1 and 1 a not recognizable). The first flat tube row 9 opens into the chamber 7 and the opposite (concealed), while the second flat tube row 10 (hidden), represented by arrows 10, in the chamber 8 and the opposite chamber (hidden) opens. On both sides of the flat tubes 2 side parts 11, 12 are arranged, which are soldered to the adjacent corrugated fins 3 and also with the collecting boxes 4, 5. The lying in the installation position side panel 12 has three elongated recesses 13, which partially share the view of the first row of flat tubes 9. These recesses 13 are provided for the drainage of condensate, which forms in humid air on the evaporator surface. The evaporator 1 has two refrigerant connections, namely a refrigerant inlet 14 and a refrigerant outlet 15, which are connected via a refrigerant supply line 16 and a refrigerant discharge line 17 to an expansion valve 18 ( Fig. 1b ). The injection of the refrigerant is thus at the bottom of the evaporator 1, and first in the air flow direction (arrow L) lying behind pipe row 10 is flowed through by refrigerant. The refrigerant then passes into the rear chamber 8 of the collecting tank 4. In the Partition 6 are arranged through openings 19, through which the refrigerant in the upstream in the direction of air flow chamber 7 (deflection in depth). From there it enters the front row of flat tubes 9 and then into the collecting box 5, the rear chamber 5a and front chamber 5b in Fig. 1b are recognizable. The refrigerant is sucked in the upper region of the chamber 5b via the connecting piece 15.

The flat tube evaporator 1 is - as already mentioned - lying, so as shown in the drawing, installed in the air conditioning of the motor vehicle and the air to be cooled in the direction of the arrow L flows. In this respect results for the flow between refrigerant and air, a cross counterflow. The flat tube evaporator has in the illustrated embodiment, a width B of 500 mm, which width includes the two headers 4, 5 with. The height H of the evaporator is 120 mm. This results in a ratio of width B to height H of 4.16.

Evaporators of this type advantageously have heights in the range of H = 65 - 142 mm, preferably of H = 98 - 120 mm.

The Figure 1c shows an evaporator in a view from below, in which the same reference numerals are used in the same components, as in FIG. 1 a. In the Figure 1c it is an embodiment in which the openings 13 'for condensate drain on the other side in comparison to the embodiment of FIG. 1a are arranged. In the embodiment of FIG. 1 a is the outlet 13 for the condensate arranged on the air inflow side in the side part, whereas in the embodiment of the Figure 1c the drain 13 'is arranged on the outflow side or outflow side in the side part.

In another embodiment, the drain for condensate condensing on the surface of the evaporator may also be on both the upstream and downstream sides of the side member.

Advantageously, the recesses are formed by elongated cutouts, but they can also be designed as round cutouts or other cutouts.

Fig. 2 shows a modified embodiment of a flat tube evaporator tube 20 in a schematic representation, ie tubes and ribs are not shown, but essentially replaced by flow arrows. The flat tube evaporator 20 has - similar to the embodiment according to Fig. 1 - A horizontal flat tube bundle 21, which has a front tube bundle half 21 a and a rear tube bundle half 21 b. However, the air flowing through the flat tube evaporator 20 in the direction of the arrow L, but first meets the rear flat tube bundle half 21 b. On both sides of the flat tube bundle 21 collector boxes 22, 23 are arranged, in which open the flat tubes, not shown, of the bundle 21. The left in the drawing collection box 22 is divided by a continuous, vertically arranged partition wall 24 in a front chamber 22a and in a rear chamber 22b, wherein the front chamber 22a has an inlet opening 25 and the rear chamber 22b has an outlet opening 26 for the refrigerant , Inlet and outlet openings 25, 26 are thus both on the lower side of the flat tube evaporator 20, which is in the position as shown in the drawing, installed in the vehicle. The right in the drawing collection box 23 has a vertically arranged partition wall 27, which divides the collection box 23 into a front chamber 23 a and 23 b in a rear chamber. The partition wall 27 has in its upper region, preferably in its upper half, three overflow openings 28 which connect the two adjacent chambers 23a, 23b to one another (fewer or more openings are also possible).

The flat tube evaporator 20 is traversed by double-flow of refrigerant, in the following manner: the refrigerant enters the direction of the arrow E via the opening 25 in the front chamber 22 a and then flows through the front tube bundle 21 a, the arrows V, in the Chamber 23a on the right side of the evaporator 20. The refrigerant enters the chamber 23a in a liquid state and partially becomes en route to the chamber 23a evaporates, that is, a portion of the inflowing into the chamber 23 a refrigerant is still liquid. Therefore, the overflow openings 28 are arranged in the upper portion of the partition wall 27, so that an overflow of liquid refrigerant from the front chamber 23 a into the rear chamber 23 b is prevented. Thus, refrigerant predominantly passes through the overflow openings 28 into the chamber 23b in the vapor state - here, in the direction of the arrow U, the deflection of the refrigerant takes place "in the depth", ie counter to the air flow direction L. The refrigerant then enters the chamber 23b the rear tube bundle 21 b and flows through this in the direction of arrow R until it enters the outlet chamber 22b. From there, the refrigerant exits in the vapor state through the outlet opening 26 in the lower region of the chamber 22 b from the flat tube evaporator 20.

By this arrangement, d. H. the above arranged in the partition 27 overflow openings 28 at the bottom inlet and outlet E, A is achieved that only vapor refrigerant is sucked and thus a control of a conventional expansion valve is possible.

A further, not shown embodiment of the flat tube evaporator is possible, with the top inlet E and outlet A (corresponding Fig. 2 ). The evaporator 20 according to Fig. 2 would be rotated about its longitudinal axis by 180 °, so that the inlet opening 25 and the outlet opening 26 would be at the top and the overflow openings 28 would come to lie in the lower half of the partition wall 27. The liquid refrigerant would then remain substantially at the bottom of the evaporator, so that only vaporous refrigerant would be sucked.

The air emerging from the flat tube evaporator carries with it part of the condensate which forms on the evaporator surface, which would lead to undesirable splashing water. For this reason, it is advantageous if in the air flow direction L behind the evaporator, a per se known, not shown here spray water grate would be arranged, which collects the spray and drains down or can drain.

Fig. 3 shows a performance comparison between conventional evaporator design with vertical tubes and inventive design with horizontal tubes. The performance of the evaporator is applied over the installed face including the collector - based on the FIGS. 1a and 2a Thus, the end face corresponds to the product B x H. The dashed line E shows the power for the inventive construction for end faces of 4 to 6.5 qdm at a constant height of H = 120 mm, starting with a width of B = 350 mm ( corresponding to a face area of 4.2 qdm). This corresponds to a ratio B to H of 2.9. The end face of 6.5 qdm corresponds to a width of B = 540 mm, which means a ratio of B to H equal to 4.5. The solid curve K, clearly below the curve E, refers to evaporators of conventional construction, ie with vertical tubes, horizontally extending headers within a ratio of B to H of 2.9 to 5.4. The reduced power compared to the construction according to the invention results from a multiplicity of refrigerant deflections and the resulting refrigerant-side pressure drop.

Fig. 4 shows another diagram in which the specific usable space, ie the ratio of usable space to installation space is plotted over the free end face (this is the product B 'x H, where B' is the width reduced by the height of the collecting boxes) , The upper dashed curve E corresponds to the construction according to the invention, while the underlying horizontally extending curve K corresponds to the conventional construction with vertical tubes. It is readily apparent that the inventive construction with lying tubes provides a relatively larger free end face, because the proportion of headers on the entire end face is substantially lower than is the case with the conventional construction in such a width-to-height ratio ,

Fig. 5 shows another diagram in which the air-side pressure drop across the evaporator is plotted over the total end face including the surface of the collector. Again, the dashed line E again the inventive and the solid line K denotes the conventional Construction. The pressure drop for the invention is therefore much cheaper. This advantage in favor of the invention results in turn due to the lower proportions of the collecting boxes on the entire end face in the invention.

Claims (9)

1. An evaporator for air-conditioning systems of motor vehicles, consisting of flow channels arranged in parallel and conducting a refrigerant, of ribs to which air is supplied and which are arranged between the flow channels and of at least one collecting chamber with refrigerant inlet and/or outlet openings, wherein the evaporator has a block with a perpendicularly measured height H and a horizontally measured width B whose product H x B yields the front surface of the evaporator, wherein the flow channels are arranged lying in a fitting position, i.e. substantially horizontally, and the collecting chamber(s) are arranged to be flowed through in the vertical direction, characterised in that the ratio V of width B to height H has the following range: $$\mathrm{2.5}\le \mathrm{V}\le \mathrm{6},\mathrm{preferably}\mathrm{3.5}\le \mathrm{V}\le \mathrm{5},$$

   

   wherein
   the flow channels are formed as flat tubes (2) and the collecting chambers are formed as collecting boxes (4, 5; 22, 23) in which the flat tubes (2) end, with two arrays (9, 10) of flat tubes (2) and collecting boxes (4, 5) arranged on both sides of the flat tube ends and respectively subdivided into two chambers (7, 8; 5a, 5b) for each flat tube array (9, 10), wherein side parts (11, 12) are arranged on both sides of the flat tube arrays (9, 10), wherein the bottom side part (12) has recesses (13) for the discharge of condensate.
2. The evaporator according to claim 1, characterised in that the refrigerant inlet opening (14) is arranged in the lower region of a chamber (5a) of a collecting box (5).
3. The evaporator according to claim 1 or 2, characterised in that the refrigerant outlet opening (15) is arranged in the upper region of a chamber (5b) of a collecting box (5).
4. The evaporator according to claim 2 or 3, characterised in that refrigerant inlet and outlet openings (14, 15) are arranged on the same collecting box (5).
5. The evaporator according to one of claims 1 to 4, characterised by a double flux (V, R) with a deflection U of the refrigerant in the depth, i.e. opposite to the air flow direction L.
6. The evaporator according to claim 4 or 5, characterised in that refrigerant inlet and outlet openings (25, 26) are arranged in the lower region of a collecting box (22) and in that the other collecting box (23) has a vertical separating wall (27) with overflow openings (28) which are arranged in the upper region.
7. The evaporator according to claim 4 or 5, characterised in that the refrigerant inlet and outlet openings are arranged in the upper region of a collecting box and in that the other collecting box has a vertical separating wall with overflow openings which are arranged in the lower region.
8. The evaporator according to one of the preceding claims, characterised in that recesses for the discharge of condensate are preferably arranged in the side part at the air exhaust side.
9. The evaporator according to one of the preceding claims, characterised in that recesses for the discharge of condensate are preferably arranged in the side part at the air inflow side.

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