HEAT EXCHANGER

Abstract

A heat exchanger (1) for a motor vehicle (2), has first flat tubes (3) with a first longitudinal end (4) received in associated first openings (5) of a first collector (6) and with an opposite second longitudinal end (7) in associated second openings (8) of a second collector (9). Second flat tubes (10) have a first longitudinal end (11) received in associated third openings (12) of a third collector (13) and a second longitudinal end (15) in associated fourth openings (16) of the second collector (9). Only the first flat tubes (3) or both the first and second flat tubes (3, 10) have an angled end region (14). The second and fourth openings (8, 16) are arranged spaced apart from one another with heat transfer fins (18) in between.

Claims

1. A heat exchanger (1) comprising: first flat tubes (3) having a first longitudinal end (4) received in associated first openings (5) of a first collector (6) and an opposite second longitudinal end (7) in associated second openings (8) of a second collector (9), second flat tubes (10) having a first longitudinal end (11) received in associated third openings (12) of a third collector (13), wherein only the first flat tubes (3) or both the first flat tubes (3,) and the second flat tubes (10) have a bent or angled end region (14), wherein the second flat tubes (10) have a second longitudinal end (15) opposite the first longitudinal end (11) received in associated fourth openings (16) of the second collector (9), and wherein the second and fourth openings (8, 16) are arranged spaced apart from one another with heat transfer fins (18) in-between.

2. The heat exchanger according to claim 1, wherein the first flat tubes (3) and second flat tubes (10) are arranged alternating.

3. The heat exchanger according to claim 1, wherein a height (H.sub.1) of the bent or angled end region (14) of the first flat tubes (3) or of both flat tubes (3, 10) maximally amounts to half of a total height (H) of the first flat tubes (3) or of both flat tubes (3, 10).

4. The heat exchanger according to claim 1, wherein a height (H.sub.1) of the bent or angled end region (14) of the first flat tubes (3) or of both flat tubes (3, 10) maximally amounts to 20% of a total height (H) of the first flat tubes (3) or of both flat tubes (3, 10).

5. The heat exchanger according to claim 1, wherein at least one of the first collector (6), the second collector (9) and the third collector (13) has a circular cross section.

6. The heat exchanger according to claim 1, wherein at least one of the first collector (6), the second collector (9), the third collector (13), the first flat tubes (3), or the second flat tubes (10) is formed from aluminium.

7. The heat exchanger according to claim 1, wherein the first collector (6) is arranged closer to the second collector (9) than to the third collector (13).

8. The heat exchanger according to claim 1, wherein the second collector (9) is arranged closer to the first collector (6) than to the third collector (13).

9. A thermal circuit (20), forming a coolant circuit or a refrigerant circuit of an air conditioning or refrigeration system for a refrigerated trailer of a motor vehicle (2), the thermal circuit comprising the heat exchanger (1) according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the drawings,

[0024] FIG. 1 shows a heat exchanger according to the invention,

[0025] FIG. 2 shows a further possible embodiment of the heat exchanger according to the invention with angled first flat tubes, and

[0026] FIG. 3 shows an embodiment analogous to FIG. 2, however with first and second angled, bent or folded flat tubes.

DETAILED DESCRIPTION OF THE DRAWINGS

[0027] According to FIGS. 1 to 3, a heat exchanger 1 according to the invention, especially for a refrigerated trailer of a motor vehicle 2, comprises first flat tubes 3 which with a first longitudinal end 4 are received in associated first openings 5 of a first collector 6, for example of an inlet distributor or of an outlet distributor, and with an opposite longitudinal end 7 in associated second openings 8 of a second collector 9, for example of a return distributor. Additionally provided are second flat tubes 10 which with a first longitudinal end 11 are received in associated third openings 12 of a third collector 13, for example of an outlet distributor or of an inlet distributor.

[0028] According to the invention, either only the first flat tubes 3 now have an angled, bent or folded end region 14 (see FIGS. 1 and 2), or both the first flat tubes 3 and the second flat tubes 10 have such a bent end region 14 (see FIG. 3). The second flat tubes 10 are additionally received with an opposite second longitudinal end 15 in associated fourth openings 16 of the second collector 9, wherein the second openings 8 and the fourth openings 16 are arranged spaced apart from one another alternating with spacing allowing heat transfer fins 18 in between. In general this means, that the openings 8 and 16 follow a 2n and 2n+1 arrangement, where n≥0.

[0029] With the embodiment of the heat exchanger 1 selected according to the invention, a higher pressure drop can be achieved through the U-shaped deflection of a fluid flow, for example of a refrigerant, within the heat exchanger 1 from the first collector 6 via the first flat tubes 3, the second collector 9, the second flat tubes 10 and the third collector 13, which reduces the risk of a freezing of the fluid flowing in the heat exchanger 1. Through the alternating arrangement of the flat tubes 3, 10 a defrosting performance can be increased and thereby a defrosting cycle shortened and an overall energy efficiency of the heat exchanger 1 increased. By both flat tubes 3, 10 opening into the second collector 9, a mixing of the fluid flowing in the heat exchanger 1, for example of the refrigerant, and thus an evening-out of the temperature in the heat exchanger 1 can be achieved. Because of the circumstance that the flat tubes 3, 10 are at least predominantly arranged in one plane (see FIG. 1), a pressure drop of an airflow flowing through the heat exchanger 1 can be additionally minimized and thereby the efficiency of the heat exchanger 1 increased. By way of the distance of the second openings 8 from the fourth openings 16, a significantly improved flow circulation about of the individual flat tubes 3, 10 and thus a higher heat transfer and a higher heat exchanger output can thereby achieved.

[0030] Practically, a height L.sub.1 of the angled, bent or folded region 14 can maximally to half of a total height L of the first flat tubes 3 or of both flat tubes 3, 10, wherein preferably a height L.sub.1 of the bent or angled region 14 of the first flat tubes 3 or of both flat tubes 3, 10 maximally amounts to 20% of the total height L of the first flat tubes 3 or of both flat tubes 3, 10. By way of this, a comparatively large region L-L.sub.1 can be created, in which the two flat tubes 3, 10 are arranged stacked above one another and parallel to one another, because of this bring about merely a low air pressure drop. The minimizing of the length “L1” simply maximizes the available heat transfer area. Leading to increased performance and efficiency.

[0031] According to the embodiment of FIG. 2, the first collector 6 can also be arranged closer to the second collector 9 than the third collector 13, as a result of which a shape of the heat exchanger 1 is optimized in terms of a depth since it is flatter, which in particular in cramped compartments is a major advantage. In the embodiment according to FIG. 3, the first and third collector 6, 13 are arranged in the air flow direction 17 one behind the other which offers the major advantage that an area that is available for the heat transfer is not negatively affected. The embodiment according to FIG. 3 additionally offers the major advantage that the first and second flat tubes 3, 10 are formed identically and merely have to be inserted into the second collector 9 flipped by 180° in an alternating order.

[0032] The heat exchanger 1 according to the invention can be incorporated in particular in a thermal circuit 20, for example in a coolant circuit or a refrigerant circuit of an air conditioning or refrigeration system of a refrigerated trailer of a motor vehicle 2, where it brings significant advantages because of its high heat exchanger output and its reduced risk of frost. The heat exchanger 1 according to the invention can also be employed in heat pump applications, for example as evaporator or as condenser, wherein in an evaporator function the first collector 6 represents an inlet distributor and the second collector 13 an outlet distributor. In the condenser mode, this is reversed.

[0033] While the above description constitutes the preferred embodiments of the present invention, the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.