JPH06241678A - Parallel flow heat exchanger for heat pump - Google Patents

Abstract

PURPOSE:To provide a parallel flow heat exchanger for a heat pump having some corrugated fins showing superior water cutting feature capable of restricting staying of condensed water while keeping superior heat transfer characteristic. CONSTITUTION:Top parts 21 of corrugated fins 2 are formed flat. it is preferable that a fin angle 61 is 0.5 to 3 deg., a length L of a flat top part 21 is 0.8mm or more, a louver length L2 is {a fin height H1-(2X plate thickness of fin)} + or -0.5mm, a louver angle theta2 is 30 to 40 deg. and a louver pitch L3 is 0.7 to 1.5mm, respectively. Each of the top parts 21. is bent to have corner portions 21a, 21b and 21c at least at three locations including a cooperating part with an intermediate wall 22 so as to form a bent sectional line the corrugated fins 2 are compressed between the adjoining tubes 1 and 1 in a height direction, top parts are deformed flat and then the corrugated fins 2 and the tubes 1 are brazed to each other under this condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for a heat pump which is used, for example, as a heat exchanger for indoor and outdoor use of a room air conditioner and which operates as an evaporator and a condenser by itself.

[0002]

2. Description of the Related Art As a heat exchanger for a heat pump as described above, attempts have been made to use a heat exchanger called a parallel flow. Such a parallel flow heat exchanger has a large number of tubes arranged in parallel, both ends of each tube are connected in communication with a pair of hollow headers, and corrugated fins are arranged between adjacent tubes. have.

As shown in FIG. 10, the corrugated fin is formed by alternately bending a top portion (41) consisting of a mountain portion and a valley portion and an intermediate wall portion (42) connecting the mountain portion and the valley portion. However, the corrugated fin (40) conventionally has the following drawbacks because the top portion (41) thereof is formed in an arc shape.

That is, when the parallel flow heat exchanger for a heat pump is used as an evaporator, condensed water is produced by heat exchange with the circulating air, and this condensed water (50) is shown by hatching in FIG. In addition, there is a drawback in that the pressure loss of the circulating air is increased by accumulating in the top portion (41) of the corrugated fin (40) arranged between the tubes (30) (30), which in turn impairs the heat exchange performance. In addition, as shown in FIG.
a) is a louver formed on the intermediate wall portion (42).

The present invention has been made in order to solve the above-mentioned drawbacks, and is a parallel for heat pump provided with corrugated fins having a good drainage property capable of suppressing the retention of condensed water while ensuring a good heat transfer property. The purpose is to provide a flow heat exchanger.

[0006]

In order to achieve the above object, the present invention is directed to a large number of tubes (1) arranged in parallel with each other, and a pair of hollow headers in which both ends of these tubes are connected for communication. (3) For a heat pump comprising (4) and a corrugated fin (2) arranged between adjacent tubes and having a top portion (21) and an intermediate wall portion (22) bent alternately in a repeating state The parallel flow heat exchanger is characterized in that the corrugated fins (2) have flat tops (21).

Further, the fin angle θ1 formed by the adjacent intermediate wall portions (22) and (22) of the corrugated fin (2) is 0.5 to 0.5.
At 3 °, the length L1 of the flat top portion (21) is defined to be 0.8 mm or more, a large number of louvers (2a) are formed on the intermediate wall portion (22), and the louver length L2 is {fin. It is desirable that the height H1− (2 × fin plate thickness)} ± 0.5 mm, the louver angle θ2 be 30 to 40 °, and the louver pitch L3 be 0.7 to 1.5 mm.

Further, according to the present invention, a large number of tubes (1) arranged in parallel, a pair of hollow headers (3) and (4) in which both ends of these tubes are connected to communicate with each other, and the adjacent tubes. A parallel flow heat exchanger for a heat pump, comprising: a corrugated fin (2) disposed between and having a top portion (21) and an intermediate wall portion (22) bent alternately in a repeating state. Each top part (21) of () is bent to have a corner part (21a) (21b) (21c) at least at three places including the connecting part with the intermediate wall part (22), and has a bent line shape in section. When the corrugated fins (2) are formed and compressed between the adjacent tubes (1) and (1) in the height direction, the top portion (21) is deformed into a flat shape, and in this state, the corrugated fins (2) are deformed. ) And the tube (1) And it is characterized in by comprising brazed.

[0009]

Since the top portion (21) is formed flat, the capillarity phenomenon is suppressed and the drainage property is improved as compared with the case where the top portion is arcuate.

The fin angle θ 1 and the flat top (21)
The length L1, the louver length L2, the louver angle θ2, and the louver pitch L3 are regulated within the respective predetermined numerical ranges, so that the reduction of the heat transfer coefficient of the fin due to the flat top portion (21) is compensated for. That is, the drainage property is improved without causing a significant decrease in the heat transfer coefficient.

Further, each of the top portions (21) of the corrugated fins (2) is bent at at least three places including a connecting portion with the intermediate wall portion (22) to be formed in a fold line shape in section, and adjacent to each other. By compressing the corrugated fins (2) in the height direction between the tubes (1) and (1), the top portion (21) is deformed into a flat shape, and in this state, the corrugated fins (2) and the tube (1) are deformed. In a parallel flow heat exchanger for a heat pump brazed with a corrugated fin (2), the top portion (21) of the corrugated fin (2) can be formed into a flat shape at the assembly stage of the heat exchanger. 2) is not required to have a flat top portion in advance, and the corrugated fin (2) can be easily manufactured.

[0012]

EXAMPLE Next, an example in which the present invention is applied to a heat exchanger made of aluminum (including its alloy) for a heat pump of a room air conditioner will be described.

3 to 5 showing the heat exchanger,
(1) is a plurality of heat exchange tubes arranged in the left-right direction in a vertical state, (2) is its adjacent tubes (1), (1)
It is a corrugated fin interposed between. The tube (1) is composed of a flat extruded shape member made of an aluminum material. The tube (1) may be of a so-called harmonica tube that is porous. Further, an electric resistance welded tube may be used instead of the extruded shape member. The corrugated fin (2) has substantially the same width as the tube (1) and is joined to the tube (1) by brazing. The corrugated fin (2) is also made of aluminum,
A cut and raised louver (2a) is used.

(3) and (4) are upper and lower headers. Each of these headers (3) and (4) is formed of an aluminum electric resistance welded pipe having a circular cross section. As shown in FIG. 5, the headers (3) and (4) are provided with tube insertion holes (5) at intervals along the length direction, and the tubes (1) are inserted into the holes (5). ) Are inserted and firmly joined and connected by brazing. Furthermore, the right end of the upper header (3) and the lower header (4)
At the left end of each, there are connection pipes (6) for refrigerant inflow and outflow.
(7) is connected. When the heat exchanger operates as an evaporator, these connecting pipes are used by the lower connecting pipe (7) for refrigerant inflow and the upper connecting pipe (6) for outflow. The liquid refrigerant flowing into the lower header (4) flows through each tube, reaches the upper header (3), and then flows out of the connection pipe (6). On the other hand, when the heat exchanger operates as a condenser, conversely to the above, the upper connecting pipe (6) is used for refrigerant inflow and the lower connecting pipe (7) is used for same outflow. Then, the gaseous refrigerant flowing from the connecting pipe (6) into the upper header (3) flows through each tube to reach the lower header (4), and then flows out of the connecting pipe (7) to the outside of the device. Has been made. A lid piece (8) is attached to the left end of the upper header (3), and a lid piece (9) is attached to the right end of the lower header (4).

As shown in FIG. 1, the corrugated fin (2) has a flat top portion (21). By forming it in a flat shape, the capillary phenomenon is suppressed and the drainage property can be improved as compared with the case of an arc shape. However, if the length L1 of the flat portion is too short, condensed water is likely to collect, so that L1 should be secured over 0.8 mm or more in order to effectively exert the effect of improving the drainage property. Further, in order to compensate for the decrease in the heat transfer coefficient of the corrugated fin (2) due to the flat shape of the top portion (21), the length L2 of the louver (2a) formed in the intermediate wall portion (22) is set to {fin Height H1-(2 x fin plate thickness)} ± 0.5 mm
It is desirable to set the fin angle θ1 to 0.5 to 3 °, the louver angle θ2 shown in FIG. 2 to 30 to 40 °, and the louver pitch L3 to 0.7 to 1.5 mm. The fin pitch L4 is generally 1.4
The fin height H1 is set to 6 to 19 mm. Particularly preferably, the length L1 of the flat portion is 1.2 m.
Range about 1 to 1.5 mm centering on m, fin angle θ
It is preferable that 1 is set to about 1.5 to 2.0 °, louver angle θ2 is set to about 40 °, and louver pitch L3 is set to about 1.2 mm.

By forming the corrugated fins (2) under the above conditions, the drainage can be improved and the pressure loss of the circulating air can be reduced without causing a significant decrease in the heat transfer coefficient. It is possible to improve the overall heat exchange performance. By the way, by using a corrugated fin in which each condition is set to the above-mentioned optimum value and a corrugated fin in which the apex (21) is formed in an arc shape, the air circulation speed Vm / s
When the pressure loss of the circulating air and the heat transfer coefficient of the fin were examined, the results were as shown in Tables 1 and 2. It should be noted that the tables 1 and 2 are graphically represented as shown in FIGS.

[0017]

[Table 1]

[Table 2] From the results of Table 1, in the corrugated fin with the arcuate top (21), the increase in the pressure loss of the circulating air when wet (when the moisture in the air is condensed) is about twice that when it is dry, but the top is flat. The corrugated fin has a ratio of 1.2 to 1.3 times, so that it can be understood that the drainage is improved and an increase in pressure loss when water in the air is condensed is suppressed.

Further, from the results of Table 2, it is understood that the heat transfer coefficient of the flat top fins to the top arc fins is about 95%, and the decrease in the heat transfer coefficient is small.

As described above, it is effective to form the top portion (21) of the corrugated fin (2) in a flat shape to improve the drainage property, but it is not possible to manufacture such a fin by high speed roll forming. Have difficulty.

Therefore, it is preferable to form the top portion (21) of the corrugated fin (2) into a flat shape as follows. That is, as shown in FIG. 7, only three corners of the corrugated fin (2), that is, both ends of the top part (21) (the connecting part of the top part and the intermediate wall part (22)) and the center part have a minute curvature. (21a)
(21b) and (21c) are bent, and the other portions are formed in a straight line portion, so that the top portion (21) is formed in a bent line cross section. In addition, the location where the corner portion is provided in the middle portion of the top portion (21) does not have to be the center,
Further, corner portions may be provided at two or more places in the intermediate portion. Here, the height (H2) of the fins (2) is set to be larger than the gap between the adjacent tubes (1) (1) in which the fins are arranged, and the height of the intermediate portion excluding the left and right tops (21). (H3) is set to be approximately equal to the gap between the tubes.

When assembling the heat exchanger, the corrugated fins (2) are arranged between the tubes (1) and (1), and then the tubes (1) and the fins are arranged in the longitudinal direction of the headers (3) and (4). (2) is compressed in the direction shown by the arrow in FIG. 7, and in this state the tube (1) is attached to the headers (3) and (4).
Insert into the tube insertion hole (5) and band. The top part (21) of the corrugated fin (2) is in contact with the tube surface only at the apex corner part (21C) as shown in FIG. 8 (a) before the tube and the fin are compressed. The fins are elastically deformed at each corner, and the top (21) is almost entirely pressed against the tube surface to be flat as shown in FIG. Then, brazing is performed in this state, and the fillet (4) is placed in the slight gap between the tube (1) and the fin (2) as shown in FIG.
0) is formed and the tops (21) of the fins (2) are joined in a flat state.

In this way, the corrugated fin (2) having the flat top portion (21) as shown in FIG. 9 can be realized.

When the heat exchanger for heat pump according to the illustrated embodiment is used as an outdoor unit for a room air conditioner, it operates as an evaporator in winter, and a liquid refrigerant or a partially gasified refrigerant is connected on the lower side. After flowing from the pipe (7) into the lower header (4), the flow is divided into each tube. The refrigerant flowing into the tube (1) exchanges heat with the air flowing through the air circulation gap including the fins (2) while flowing upward through the tube, gasifies and reaches the header (3), It flows out of the device through the upper connecting pipe (6). Condensed water is generated from the circulating air during heat exchange, but since the top part (21) of the corrugated fin (2) is formed flat, the capillarity phenomenon is suppressed and the condensed water collects on the top part. Not promptly discharged.

On the other hand, in summer, the refrigerant operates as a condenser, and the refrigerant flowing from the upper connecting pipe (6) into the upper header (3) is
Each tube flows downward, heat is exchanged with circulating air during this time, and liquefies to reach the lower header (4). And
It flows out from the lower connecting pipe (7).

[0025]

According to the present invention, the top of the corrugated fin is formed flat as described above, so that the retention of the condensed water generated from the moisture in the air can be suppressed and the drainability is improved. be able to. As a result, it is possible to prevent deterioration of the heat exchange performance due to the retention of condensed water, and it is possible to provide a parallel flow heat exchanger for a heat pump having excellent performance.
Moreover, since the top is flat, a large bonding area between the tube and the corrugated fin can be secured, and a heat exchanger excellent in strength can be obtained.

Further, the fin angle .theta.1 formed by the adjacent intermediate wall portions of the corrugated fins is set to 0.5 to 3 DEG, the length L1 of the flat top portion is set to 0.8 mm or more, and a large number of intermediate wall portions are formed. Louver is formed and louver length L2
Is {fin height H1− (2 × fin plate thickness)} ± 0.5
mm, the louver angle θ2 is 30 to 40 °, and the louver pitch L3 is 0.7 to 1.5 mm, the heat transfer coefficient of the fin is reduced due to the flat top. It is possible to effectively prevent the condensed water from accumulating while sufficiently supplementing it, and it is possible to further improve the performance of the parallel flow heat exchanger for the heat pump.

Further, each apex of the corrugated fin is bent in at least three places including a connecting portion with the intermediate wall to be formed into a bent line shape, and the corrugated fin is elevated between adjacent tubes. The top part of the corrugated fin is flattened at the assembly stage in the parallel flow heat exchanger for heat pump in which the top part is deformed into a flat shape by being compressed in the direction, and the corrugated fin and the tube are brazed in this state. Since the corrugated fins can be formed into a shape, it is not necessary to manufacture the corrugated fins in advance with flat tops, the corrugated fins can be manufactured easily, and a parallel flow heat exchanger for a heat pump with excellent drainage can be provided at low cost. There is an effect that can be done.

[Brief description of drawings]

1 is an enlarged front view of a corrugated fin used in the heat exchanger shown in FIG.

FIG. 2 is a cross-sectional view of the corrugated fin of FIG. 1 in the width direction.

FIG. 3 is a front view of a parallel flow heat exchanger for heat pump according to an embodiment of the present invention.

FIG. 4 is a side view of the same.

5 is a sectional perspective view showing a lower header, tubes and fins of the heat exchanger shown in FIG.

FIG. 6 is a graph showing a comparison between the water draining performance and the heat transfer coefficient when a fin having a flat top and a fin having an arc are used.

FIG. 7 is an enlarged front view showing a fin material for forming a corrugated fin having a flat top portion.

8 is a partially enlarged front view showing a process of arranging the fin material shown in FIG. 7 between the tubes, compressing and brazing.

9 is an enlarged front view of a state in which a tube and a corrugated fin are brazed using the fin material shown in FIG.

FIG. 10 is an enlarged front view showing a water retention state of condensed water when a conventional corrugated fin having an arcuate top is used.

[Explanation of symbols]

 1 ... Tube 2 ... Corrugated fin 3, 4 ... Header 2a ... Louver 21 ... Top 22 ... Intermediate wall 21a to 21c ... Corner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Yoshinaga 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi Co., Ltd. Tochigi factory (72) Inventor Hiroshi Kogure 800 Tomita, Ohira-machi, Shimotsuga-gun, Tochigi Hitachi Co., Ltd. Tochigi factory (72) Inventor, Ryoichi Hoshino, 6-224, Kaiyamacho, Sakai City, Osaka Prefecture, Showa Aluminum Co., Ltd. (72) Inventor, Nobuhiro Wakabayashi, 6-224, Kaiyamacho, Sakai City, Osaka Prefecture

Claims (3)

[Claims] 1. A plurality of tubes (1) arranged in parallel, a pair of hollow headers (3) (4) in which both ends of these tubes are connected in communication, and arranged between adjacent tubes. And a corrugated fin (2) in which the top portion (21) and the intermediate wall portion (22) are bent alternately in a repeating state, the parallel flow heat exchanger for a heat pump comprising: a top portion of the corrugated fin (2) ( 21) A parallel flow heat exchanger for a heat pump, characterized in that it is formed in a flat shape. 2. The fin angle θ1 formed by the adjacent intermediate wall portions (22), (22) of the corrugated fin (2) is 0.5 to 3 °.
The length L1 of the flat top (21) is specified to be 0.8 mm or more, and a large number of louvers (2a) are provided on the intermediate wall (22).
And the louver length L2 is {fin height H1
-(2 x fin plate thickness)} ± 0.5 mm, louver angle θ2 of 30 to 40 °, and louver pitch L3 of 0.7 to
The parallel flow heat exchanger for a heat pump according to claim 1, wherein the parallel flow heat exchanger has a size of 1.5 mm. 3. A large number of tubes (1) arranged in parallel, a pair of hollow headers (3) (4) in which both ends of these tubes are connected in communication, and arranged between adjacent tubes. And a corrugated fin (2) in which the top portion (21) and the intermediate wall portion (22) are bent alternately in a repeating state, wherein each top portion of the corrugated fin (2) is provided. (21) is bent to have a corner portion (21a) (21b) (21c) at least at three places including a continuous portion with the intermediate wall portion (22), and is formed in a polygonal line shape in cross section. By compressing the corrugated fins (2) in the height direction between the adjacent tubes (1) and (1), the top portion (21) is deformed into a flat shape, and in this state, the corrugated fins (2) and the tubes (2) are 1) is brazed with Parallel flow heat exchanger for a heat pump, wherein the door.