JP2015152178A - Off-set fin for heat exchanger and refrigerant heat exchanger using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an off-set fin for a heat exchanger and refrigerant heat exchanger using the off-set fin highly advanced in performance remarkably by efficiently combining individual improvement factors of the off-set fin.SOLUTION: An off-set fin 5 for a heat exchanger arranged between a plurality of refrigerant tubes which are arranged in parallel with each other, the off-set fin 5 comprises a number of segments 10, which are individual fins, cut and raised into strips on a rising surface 8 and a falling surface 9 of the fin which is folded in a wave form, the number of segments being arranged in the state of being offset along an air flow direction with intervals of two lines or more, in which 0.5 mm≤L≤1.2 mm, where the length of each segment 10 in the air flow direction is L, and the division number within one pitch of the wave form fin of the individual segment 10 is three or more.

Description

  The present invention relates to a heat exchanger offset fin provided between refrigerant tubes and a refrigerant heat exchanger using the same.

  As a refrigerant heat exchanger applied to an evaporator or a condenser of an air conditioner, a corrugated fin formed by bending a metal thin plate into a corrugated shape between a plurality of refrigerant tubes arranged in parallel is arranged. Conventionally known. In addition, in order to further improve the heat exchange performance with respect to the corrugated fins, a large number of segments, which are individual fins cut and raised in a strip shape, are arranged on both sides of the corrugated fin's corrugated rising surface and falling surface. A refrigerant heat exchanger having a configuration in which so-called offset fins are arranged between refrigerant tubes is also known.

  On the other hand, Patent Document 1 discloses an exhaust gas heat exchanger in which offset fins are arranged as inner fins in a tube, in which four offset fin pieces are arranged at predetermined intervals (slits) on the offset fins. . Similarly, in an exhaust gas heat exchanger in which offset fins are arranged in the exhaust tube, each segment exists in a specific row and column so as not to be affected by the temperature boundary layer generated at the leading edge of the upstream segment. Patent Document 2 discloses an inclination toward the center of any one of the segments other than the segment.

  Further, the fin pitch fp of the offset fins arranged in the exhaust tube of the exhaust gas heat exchanger is set to satisfy 2 mm <fp ≦ 12 mm, the fin height fh satisfies 3.5 mm <fh ≦ 12 mm, and the individual fins are raised. When the length L of the segment is fh <7, fp ≦ 5, 0.5 mm <L ≦ 7 mm, fh <7, fp> 5, 0.5 mm <L ≦ 1 mm, fh ≧ 7, when fp ≦ 5, 0.5 mm <L ≦ 4.5 mm, fh ≧ 7, and when fp> 5, 0.5 mm <L ≦ 1.5 mm is shown in Patent Document 3. Yes.

JP 2009-139053 A JP 2001-41109 A Japanese Patent No. 4240136

  As described above, in the offset fin, the length L of each segment is defined in relation to the fin pitch fp and the fin height fh, each segment is inclined with respect to the air flow direction, or each segment is The heat transfer coefficient is improved by increasing the number of divisions per pitch of the corrugated fins. However, each improvement measure improves the heat transfer coefficient on the gas side and improves the performance by suppressing pressure loss. The limit is being reached. Under such circumstances, there is a demand for providing a heat exchanger with higher performance in a refrigerant heat exchanger applied to an evaporator, a condenser, or the like of a vehicle air conditioner.

  The present invention has been made in view of such circumstances, and by effectively combining the individual improvement elements of the offset fin, the offset fin for a heat exchanger that is further improved in performance and a refrigerant using the same. An object is to provide a heat exchanger.

In order to solve the above problems, the offset fin for heat exchanger of the present invention and the refrigerant heat exchanger using the same employ the following means.
That is, the offset fin for a heat exchanger according to the present invention is an offset fin for a heat exchanger disposed between a plurality of refrigerant tubes arranged in parallel, and a rising surface and a falling surface of a fin bent into a corrugated shape A number of segments, which are individual fins cut and raised in a strip shape on the surface, are arranged in an offset manner with two or more rows spaced along the air flow direction, and the length L of each segment in the air flow direction. However, 0.5 mm ≦ L ≦ 1.2 mm, and the number of divisions in one pitch of the corrugated fin of each segment is 3 or more.

  According to the present invention, the segments which are individual fins cut and raised in a strip shape on the rising surface and the falling surface of the corrugated fins constituting the offset fin are spaced apart by two or more rows along the air flow direction. A large number of offsets are provided, and the length L in the air flow direction of each segment is 0.5 mm ≦ L ≦ 1.2 mm. Therefore, for each segment, the segment located upstream in the air flow direction By preventing the temperature boundary layer generated at the leading edge from affecting the segments disposed downstream and not disturbing the leading edge effect, the leading edge effect of each segment, i.e., each The air flow collides with the front edge of the segment, and the effect of locally increasing the heat transfer coefficient at the front edge is maximized, improving the heat transfer coefficient on the air side, and consequently At the same time it is possible to improve the exchange performance, the air side pressure loss is suppressed by optimizing the length L of the air flow direction of each segment, it is possible to suppress the pressure loss to a practical range. Further, by setting the number of corrugated fins in each segment to be 3 or more, the space between the fins can be narrowed to increase the air flow speed and further improve the heat transfer coefficient on the air side. it can. Therefore, the performance of the offset fin can be improved from both the air side heat transfer coefficient and the pressure loss, and the performance can be further improved.

  Furthermore, the offset fin for a heat exchanger according to the present invention is the above-described offset fin for a heat exchanger, wherein the individual segments in which the number of divisions in the one pitch is 3 or more are repeatedly arranged in three or more stages. It is characterized by being.

  According to the present invention, since the individual segments whose number of divisions in one pitch is 3 or more are repeatedly arranged in a step shape of 3 or more, all segments are arranged in two rows along the air flow direction. It can be offset and opened, eliminating the influence of the temperature boundary layer of the upstream segment in all segments, maximizing the leading edge effect and steadily improving the heat transfer coefficient on the air side . Therefore, the heat exchange performance of the offset fin can be further improved.

  Furthermore, the offset fin for a heat exchanger according to the present invention is characterized in that in any one of the above-described offset fins for a heat exchanger, the individual segments are inclined at a predetermined angle with respect to the air flow direction.

  According to the present invention, since the individual segments are inclined at a predetermined angle with respect to the air flow direction, the interval between the individual segments is widened by the inclination, and the air flow is rectified, whereby the individual flow is rectified. The heat transfer coefficient can be further improved by the leading edge effect of the segment, and the effect of suppressing the air side pressure loss can be maintained. Therefore, the performance of the offset fin can be improved. In addition, the inclination angle of the segment is desirably about 7 ° from the relationship with the pressure loss.

  Furthermore, the refrigerant heat exchanger according to the present invention is characterized in that any one of the aforementioned heat exchanger offset fins is disposed between a plurality of refrigerant tubes arranged in parallel at a predetermined interval.

  According to the present invention, since any one of the aforementioned heat exchanger offset fins is disposed between the plurality of refrigerant tubes arranged in parallel at a predetermined interval, the refrigerant flowing in the refrigerant tube and the offset fin side The heat exchange with the airflow flowing through the airflow can be further promoted by improving the performance of the offset fin, and the heat exchange performance can be improved. Therefore, it is possible to further improve the performance of the refrigerant heat exchanger applied to the evaporator and the condenser and improve the performance of the air conditioner, and to reduce the size of the unit by downsizing the evaporator and the condenser. Can do.

  According to the offset fin for a heat exchanger of the present invention, for each segment, the temperature boundary layer generated at the leading edge of the segment located on the upstream side in the air flow direction affects the segment arranged on the downstream side. By making it difficult and not hindering its leading edge effect, the leading edge effect of each segment, i.e., the air flow impinges on the leading edge of each segment, and the heat transfer rate at that leading edge region is locally The effect of increasing the pressure can be maximized, the heat transfer coefficient on the air side can be improved, and the heat exchange performance can be improved. At the same time, the length L in the air flow direction of each segment is optimized to optimize the air side. The pressure loss can be suppressed and the pressure loss can be suppressed to a practical range. Further, by setting the number of corrugated fins in each segment to be 3 or more, the space between the fins can be narrowed to increase the air flow speed and further improve the heat transfer coefficient on the air side. Therefore, the performance of the offset fin can be improved in terms of both the heat transfer coefficient and the pressure loss on the air side, and the performance can be further improved.

  Further, according to the heat exchanger of the present invention, heat exchange between the refrigerant flowing in the refrigerant tube and the air flow flowing on the offset fin side is further promoted by improving the performance of the offset fin, and the heat exchange performance is improved. Therefore, the refrigerant heat exchanger applied to the evaporator and condenser can be further improved in performance to improve the performance of the air conditioner, and the evaporator and condenser can be downsized to make the unit more compact. Can be achieved.

It is a perspective view of the refrigerant | coolant heat exchanger which concerns on one Embodiment of this invention. It is a perspective view of the offset fin used for the said heat exchanger. It is an AA cross-section equivalent figure in FIG. FIG. 3 is a view corresponding to arrow B in FIG. 2. It is a performance comparison figure of the said offset fin and its modification, and a single offset fin. It is a figure which shows the change of the air pressure loss by the length L of each segment of the said offset fin. It is a figure which shows the change of the heat transfer rate by the length L of each segment of the said offset fin. FIGS. 8A to 8H are cross-sectional equivalent views (A) to (H) showing the arrangement specifications of the offset fin segments used in the performance comparison and analysis shown in FIGS.

An embodiment according to the present invention will be described below with reference to FIGS.
FIG. 1 is a perspective view of a refrigerant heat exchanger according to an embodiment of the present invention, FIG. 2 is a perspective view of offset fins used in the heat exchanger, and FIG. FIG. 4 shows a view corresponding to the arrow B in FIG. 2.
The refrigerant heat exchanger 1 is applied to an evaporator or a condenser for an air conditioner, and exchanges heat between the refrigerant flowing in the refrigerant tube and the air flowing outside the refrigerant tube.

  The refrigerant heat exchanger 1 includes a pair of upper and lower or left and right headers 2 and 3 provided in a pair at the front and rear with respect to the air flow direction F at regular intervals in the vertical and horizontal directions, and between the headers 2 and 3 By connecting both ends, it is composed of a large number of flat refrigerant tubes 4 arranged in parallel at predetermined intervals, and offset fins 5 arranged between the parallel refrigerant tubes 4, After the refrigerant supplied from the refrigerant inlet pipe 6 connected to the header 2 is circulated through the refrigerant tube 4 by one or more passes, the heat is exchanged with air during that time, and the other is evaporated or condensed. The refrigerant is discharged from the refrigerant outlet pipe 7 connected to the header 3.

  The refrigerant heat exchanger 1 is an all-aluminum alloy heat exchanger in which the pair of headers 2 and 3, the refrigerant tubes 4, the offset fins 5, and the like constituting the refrigerant heat exchanger 1 are all made of an aluminum alloy. As shown in FIGS. 2 to 4, the offset fin 5 is, for example, a fin width w obtained by bending an aluminum alloy thin plate having a plate thickness tf of 0.06 mm into a waveform with a fin pitch pf of 1.3 mm. Is a 34 mm fin, and a large number of segments (strips) 10, which are individual fins cut and raised in a strip shape, are arranged on both sides of the rising surface 8 and the falling surface 9 of the fin that is bent into a corrugated shape. It has been configured.

  Further, in the present embodiment, in order to improve the performance of the offset fin 5, the air flow direction F of the strip-shaped segment 10 which is individual fins cut and raised on both the rising surface 8 and the falling surface 9 of the corrugated fin. The length L is 0.5 mm ≦ L ≦ 1.2 mm, and the plurality of segments 10 are arranged in two or more rows in the row direction along the air flow direction F, as shown in FIG. It is set as the structure arranged at intervals. Each segment 10 has a division number n of 3 or more in the direction orthogonal to the air flow direction F within one pitch of the corrugated fins.

  Further, when each segment 10 is divided into three or more in the direction orthogonal to the air flow direction F, all the segments 10 are spaced by two or more rows in the row direction along the air flow direction F. In order to arrange them with a gap, as shown in FIG. 2 and FIG. 3, a configuration in which three or more stages are formed and sequentially arranged in the air flow direction F is adopted.

Here, the analysis result and calculation result of the sample performed to confirm the performance of the offset fin 5 will be described with reference to FIGS.
First, the NO. Of the offset fin used for the analysis and calculation. 1-NO. The specification of 9 samples will be described with reference to FIGS.
In any sample, the fin material plate thickness tf is 0.06 mm, the fin pitch pf is 1.3 mm, the fin width w is 34 mm, and the length L in the air flow direction F of each segment 10 is 1 mm. The arrangement, arrangement, and the like of the segments 10 that are individual fins are changed.

(1) NO. As shown in FIG. 8 (A), one sample of fins has a row in the row direction of each segment 10 and a direction perpendicular to the air flow direction F in one pitch of each segment 10. The number of divisions n is 2.
(2) NO. As shown in FIG. 8 (B), the two-sample fins have two rows in the row direction of the individual segments 10 and are in a direction perpendicular to the air flow direction F in one pitch of each segment 10. The number of divisions n is 3, and the segment 10 is repeatedly arranged in the air flow direction F in a three-stage shape.

(3) NO. As shown in FIG. In two samples, the division number n in the direction orthogonal to the air flow direction F within one pitch of each segment 10 is 4, and the segments 10 are sequentially arranged in the air flow direction F in a four-stage shape. .
(4) NO. As shown in FIG. In two samples, each segment 10 is disposed with an inclination of 7 ° with respect to the air flow direction F.

(5) NO. As shown in FIG. In two samples, the step shape is folded back at the center in the air flow direction F and sequentially arranged.
(6) NO. As shown in FIG. 8 (F), the 6-sample fin has a division number n of 3 in the direction orthogonal to the air flow direction F within one pitch of each segment 10, but the step shape is 3 This is a repeated arrangement of stepped folds. For this reason, there are a mixture of individual segments 10 in which the interval in the column direction is one column.

(7) NO. As shown in FIG. In six samples, each segment 10 is disposed with an inclination of 7 ° with respect to the air flow direction F.
(8) NO. As shown in FIG. 8H, the 8-sample fin is a known corrugated fin with a louver that is folded at the center in the air flow direction F.
(9) NO. Nine sample fins are not shown, but the above NO. In 6 samples, the number n of divisions in the direction orthogonal to the air flow direction F within one pitch of each segment 10 is set to 4, and therefore, the interval in the column direction of each segment 10 is one row. Are mixed.

  The above-mentioned NO. 1-NO. FIG. 6 and FIG. 7 show the results of calculating and analyzing changes in the air pressure loss ΔPa (Pa) and the heat transfer coefficient hm (W / m 2 K) depending on the length L (mm) of each segment 10 for 7 samples. ing. The heat transfer coefficient hm. pp and air pressure loss ΔPa. The calculation formula of pp is in the calculation area shown in FIG. 8 and is as follows.

[Definition of loss factor]
fL = 1/4 [{1 + 3.445 / (Re · 2de / L · 1/4) ^ 0.5} ^ 2-1] × (2de / L)
Where Re: Reynolds number, de: equivalent diameter, L: segment length [pressure loss; ΔPa. pp]
ΔPa. pp = 2fL · (L / (2de)) · ρa · uθ ^ 2 × c × NL
Where c: pressure loss correction coefficient, ρa: air density, uθ: inter-segment flow velocity, NL: number of segments in the depth direction between one pitch [heat transfer rate; hm. pp]
Nu = 3.77 + [0.066 · (Re · Pra · de / (2L)) ^ 1.2] / [1 + 0.1 · (Pra) ^ 0.87 · (Re · de / (2L)) ^ 0.7]
Nu = hm. pp · de / λa
However, Pra: Air Prandtl number, λa: Air thermal conductivity

  FIG. 6 shows the result of analyzing the change in the air pressure loss ΔPa depending on the length L (mm) of each segment 10. Here, when the pressure loss setting line (estimation) of the air pressure loss ΔPa (Pa) is 100.0 Pa, the air pressure loss ΔPa (Pa) is shown in FIG. It is desirable to suppress within the dotted line frame shown in FIG. 2-NO. 5 and NO. Seven samples are included in that range. These samples are determined according to the number of divisions within one pitch of the segment 10, the interval in the column direction, the inclination with respect to the air flow direction F, etc. 1 and NO. Although the air pressure loss is relatively higher than that of the sample of 6, it can be set to a practical range.

  On the other hand, FIG. 7 shows the result of analyzing the change in the heat transfer coefficient hm according to the length L (mm) of each segment (strip) 8. Here, when the heat transfer coefficient reaching line (estimated) of the heat transfer coefficient hm (W / m2K) is 400.0 hm, the heat transfer coefficient hm is seen from the relationship with the length L of each segment (strip) 8. (W / m2K) is a preferable range within the dotted frame shown in FIG. 2-NO. 5 and NO. Seven samples are included in that range. These samples are determined according to the number of divisions within one pitch of the segment 10, the interval in the column direction, the inclination with respect to the air flow direction F, etc. 1 and NO. The heat transfer coefficient can be made relatively higher than that of the sample 6 and the performance can be improved.

Furthermore, FIG. 5 shows a performance comparison diagram with a single offset fin that evaluates the performance of the offset fin from both the aspects of heat transfer coefficient and air pressure loss.
Here, the advantage of the arrangement of the segments 10 in each offset fin is that the pressure loss ratio (ΔPa.ratio) and the heat transfer coefficient ratio (hm.ratio) are respectively ΔPa / ΔPa. PP <1.0
hm / hm. PP> 1.0
The performance was evaluated based on whether or not it was in the area.

  As a result, NO. 3 and NO. It can be evaluated that the 4-sample offset fin is the most excellent in performance. This NO. 3 and NO. The four sample offset fins are NO. For two offset fins, the number of segments 10 in one pitch is increased, or the segment 10 is inclined with respect to the air flow direction F by a predetermined angle (7 °). Therefore, increasing the number of segments 10 or tilting the segment 10 by a predetermined angle slightly increases the pressure loss ratio (ΔPa.ratio) but increases the heat transfer ratio (hm.ratio). It turns out that it is effective in doing.

In particular, it is effective to incline the segment 10 to improve the heat transfer coefficient ratio. 6 samples and NO. It is clear from the comparison with 7 samples.
In addition, NO. 2 and NO. The five sample offset fins are also Like the three or four sample offset fins, it is in the above-mentioned evaluation region, and it was found that the pressure fin ratio and the heat transfer coefficient ratio are sufficiently in practical use from both sides. This NO. 2 and NO. Each of the 5-sample offset fins has two rows in the row direction of the individual segments 10, and the division number n in the direction perpendicular to the air flow direction F in one pitch of each segment 10 is 3. It is.

  Therefore, the interval between the individual segments 10 in the row direction is set to two or more rows, and the temperature boundary layer generated at the leading edge of the segment 10 arranged on the upstream side in the air flow direction F is downstream of each segment 10. It is difficult to affect the segments 10 arranged in the space, and the leading edge effect of the individual segments 10, that is, the air flow collides with the leading edge of each segment 10. Thus, it has been found that the effect of locally increasing the heat transfer coefficient hm at the leading edge portion is exhibited to the maximum, and it is effective in improving the heat transfer coefficient hm on the air side.

  Further, in this way, when the individual segments 10 are arranged with a large number of offsets at intervals of two or more rows along the air flow direction, NO. As shown in Samples 6 and 7, there is a mixture of items in which the interval in the column direction is one column. It has been found that it is desirable to have a configuration in which all segments 10 are repeatedly arranged in three or more steps so that all the segments 10 are offset with two or more intervals, as in 2 to 5 samples. This is because the number of divisions n in one pitch is 4. Nine sample fins (similar to the NO.6 sample fins, the step shape is a four-step repeated arrangement). It is also clear from the lower performance than the 2 or 5 sample fins.

From the above analysis results, in order to improve the performance of the offset fins, a large number of segments 10 are designated as NO. 2 to NO. It can be said that it is desirable to provide the following three conditions that all the five sample fins satisfy.
A. A large number of individual segments 10 are arranged with an interval of two or more rows along the air flow direction.
B. The length L of each segment 10 in the air flow direction is set to 0.5 mm ≦ L ≦ 1.2 mm, more preferably 0.6 mm ≦ L ≦ 1.0 mm.
C. The number of divisions within one pitch of the corrugated fin of each segment 10 is set to 3 or more.

  However, when the number of divisions within one pitch of each segment 10 is 3 or more, it is desirable that the step shape is a repetitive arrangement of three or more step shapes. Since the number of divisions within one pitch becomes more difficult as the number increases, 3 to 4 are in an appropriate range, and it is also possible to provide each segment 10 at a predetermined angle, or heat transfer. Although it is possible to increase the rate, there are aspects in which the manufacturability is lowered, and therefore, it is only necessary to determine whether or not to adopt it in consideration of such points.

  Thus, in the present embodiment, the segments 10, which are individual fins cut and raised in the shape of strips on the rising surface 8 and the falling surface 9 of the corrugated fins constituting the offset fin 5, are arranged in the air flow direction F. A large number of offsets are arranged at intervals of two or more rows, and the length L of each segment 10 in the air flow direction F is 0.5 mm ≦ L ≦ 1.2 mm. 10, the temperature boundary layer generated at the leading edge of the segment 10 disposed on the upstream side in the air flow direction F does not easily affect the segment 10 disposed on the downstream side, and does not hinder the leading edge effect. By doing so, the leading edge effect of each segment 10, that is, the air flow collides with the leading edge of each segment 10, and the heat transfer coefficient hm locally increases at that portion. It is possible to maximize the results, improve the heat transfer coefficient hm on the air side, and thus improve the heat exchange performance, and at the same time suppress the air side pressure loss ΔPa by optimizing the length L of each segment 10 And it can be suppressed to a practical range.

Further, by setting the number of corrugated fins of a large number of offset segments 10 within one pitch to be 3 or more, the space between the fins is narrowed to increase the air flow speed, and the heat transfer coefficient hm on the air side is increased. Can be further improved.
Therefore, the performance of the offset fin 5 can be improved from both sides of the air-side heat transfer coefficient hm and the pressure loss ΔPa, and the performance can be further improved.

  In particular, each segment 10 in which the number of divisions in one pitch is 3 or more is repeatedly arranged in a step shape of 3 or more, so that all the segments 10 are opened in two or more rows along the air flow direction F. Can be offset and can eliminate the influence of the temperature boundary layer of the upstream segment 10 in all the segments 10 to maximize the leading edge effect and steadily improve the heat transfer coefficient on the air side. . Thereby, the heat exchange performance of the offset fin 5 can be further improved.

  Furthermore, in this embodiment, each segment 10 is inclined with respect to the air flow direction F by a predetermined angle (7 °). For this reason, by increasing the interval between the individual segments 10 by an amount corresponding to the inclination and rectifying the air flow, it is possible to further improve the heat transfer coefficient hm due to the leading edge effect of the individual segments 10 and to improve the air flow. The effect of suppressing the side pressure loss ΔPa can be maintained. Therefore, the performance of the offset fin 5 can be improved.

  Further, the refrigerant heat exchanger 1 of the present embodiment is configured such that the heat exchanger offset fins 5 are arranged between a plurality of refrigerant tubes 4 arranged in parallel at predetermined intervals. For this reason, heat exchange between the refrigerant flowing in the refrigerant tube 4 and the air flow flowing on the offset fin 5 side can be further promoted by improving the performance of the offset fin 5, and the heat exchange performance can be improved. As a result, the refrigerant heat exchanger 1 to which the evaporator and the condenser are applied can be further improved in performance and air conditioning performance can be improved, and the size of the unit can be reduced by downsizing the evaporator and the condenser. Can do.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the above embodiment, as an example of the refrigerant heat exchanger, a number of refrigerant tubes are arranged in parallel between a pair of headers, and offset fins are arranged between the refrigerant tubes. Needless to say, the present invention can be similarly applied to a heat exchanger having a configuration in which flat tubes are bent in a meandering manner and offset fins are provided between parallel tubes. The refrigerant tube may be a refrigerant tube having any configuration such as an extruded tube or a laminate tube.

1 Refrigerant Heat Exchanger 4 Refrigerant Tube 5 Offset Fin 8 Rising Surface 9 Falling Surface 10 Segment (Strip)

Claims (4)

An offset fin for a heat exchanger disposed between a plurality of refrigerant tubes arranged in parallel,
A large number of segments, which are individual fins cut and raised in a strip shape on the rising surface and falling surface of the fins bent into a corrugated shape, are arranged at intervals of two or more rows along the air flow direction. With
The length L in the air flow direction of each segment is 0.5 mm ≦ L ≦ 1.2 mm,
An offset fin for a heat exchanger, wherein the number of divisions in each pitch of the corrugated fin of each segment is 3 or more.   2. The offset fin for a heat exchanger according to claim 1, wherein the individual segments each having a division number of 3 or more in one pitch are repeatedly arranged in a step shape of 3 or more.   The offset fin for a heat exchanger according to claim 1 or 2, wherein the individual segments are inclined at a predetermined angle with respect to the air flow direction. A heat exchanger offset fin according to any one of claims 1 to 3, wherein the heat exchanger offset fin is disposed between a plurality of refrigerant tubes arranged in parallel at a predetermined interval.

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