JP5554741B2 - Finned tube heat exchanger and air conditioner equipped with the same - Google Patents

Description

  The present invention relates to a finned tube heat exchanger and an air conditioner equipped with the same, and is particularly suitable as a heat exchanger for an indoor unit of an air conditioner.

  A conventional finned tube heat exchanger is composed of a plurality of plate-like fins arranged in parallel with each other at regular intervals, and a heat transfer tube that snakes through the plate-like fins in the normal direction. Heat exchange is performed between the air flowing between the fins and the refrigerant flowing inside the heat transfer tube.

  In recent years, there has been a strong demand for reducing energy consumption in air conditioners from the viewpoint of preventing global warming, and there has been increased interest in reducing energy consumption when manufacturing air conditioners and reducing material resources used.

  Under such circumstances, in the fin tube heat exchanger, as shown in Patent Document 1, it is possible to reduce energy consumption while ensuring compactness by reducing the diameter of the heat transfer tube and optimizing the slit shape of the fin. An efficient heat exchanger has been proposed.

  Moreover, as a conventional fin tube type heat exchanger, as shown in Patent Document 2, the slit height provided in the fin is lowered as it moves away from the fin center line in the front-rear direction (upstream side and downstream side). A slit has been proposed in which the height of the slit is increased toward the downstream side from the fin center line.

JP 2009-198055 A Japanese Patent Laid-Open No. 10-206085

  The thing of the said patent document 1 is proposed about the diameter of a heat exchanger tube, a step pitch, a row pitch, the cutting height of a slit, etc. About the dimensional error at the time of manufacture of a fin tube heat exchanger, or an assembly Not considered. For this reason, even if the product can be manufactured according to the specified dimensions, even if the specified performance can be ensured, the aging of the mold, which is the fin manufacturing device, and the bending of the fin tube heat exchanger A slight deformation of the fin shape is unavoidable due to deformation caused by external force during processing, transportation, assembly, etc. Recently, as shown in Patent Document 1, in order to increase the efficiency of the fin tube heat exchanger, its heat transfer tube diameter tends to be reduced to about 4 to 6 mm (smaller diameter). If the fin pitch, step pitch, row pitch, etc. are reduced and the density is increased, the performance degradation due to the deformation of the fin shape is unavoidable. Therefore, the energy consumption reduction effect of the air conditioner is fully demonstrated. It becomes difficult to do. Also, if the dimensions such as heat transfer tube outer diameter, row pitch, step pitch, fin pitch, etc. are reduced in size and density, the fin itself will be less rigid, so a heat exchanger will be installed to prevent dimensional errors. It is difficult to manufacture or the workability is remarkably deteriorated.

  In high-density heat exchangers with reduced heat transfer tube diameter and reduced fin pitch, step pitch, row pitch, etc., even if the fins have slits, they are provided upstream of the air flow. The temperature boundary layer generated by the formed slit is likely to cause interference with the temperature boundary layer of the slit located on the downstream side thereof, and it becomes difficult to exert the heat transfer promotion effect by the leading edge effect by slit cutting and raising. Furthermore, if the fin tube heat exchanger is made by reducing the pitches, the ventilation resistance due to slit cutting is likely to increase.

  Furthermore, the fin tube heat exchanger described in Patent Document 1 requires a long dimension on the step pitch side even if it can be used for a ceiling-embedded air conditioner having a small step pitch side dimension (vertical dimension). For example, in a floor-mounted air conditioner, the rigidity as a heat exchanger is insufficient, and the product strength is not considered.

  In the thing of patent document 2, the slit height provided in the fin is made low as it goes back and forth from the fin center line, or the slit height is made high as it goes downstream from the center line, and it occurs in the slit part. Although it has been described that the heat transfer is promoted by preventing the influence of the temperature boundary layer, dimensional errors during manufacture and assembly of the fin tube heat exchanger, especially the heat transfer tube outer diameter, row pitch, step pitch, fin No consideration has been given to dimensional errors when dimensions such as pitch are miniaturized and densified.

  Moreover, in the thing of patent document 2, although the airflow which flows is turbulently mixed by the said slit, it is trying to reduce the dead water area which arises in a heat exchanger tube back stream, but with respect to the centerline of the row direction of a fin. Since it is not a symmetric shape, deformation such as bending of the fin is likely to occur when forming a long fin, and there is a problem in improving productivity. In addition, although the thing made into the symmetrical shape with respect to the centerline of the row direction of a fin is described, since the slit of the heat-transfer tube back stream side (downstream side) is a thing with a low height, airflow No consideration is given to the fact that the effect of reducing the dead water area by guiding it to the downstream side of the heat transfer tube is reduced.

  An object of the present invention is to provide a finned tube heat exchanger capable of suppressing performance degradation due to deformation of the fin shape even when the heat transfer tube is reduced in diameter and the fins are reduced in size and increased in density, and an air including the same. It is to obtain a harmony machine.

In order to achieve the above-mentioned object, the present invention is configured so that a plurality of plate-like fins arranged so as to allow gas to pass through each other at a predetermined interval and the plate-like fins penetrate and meander. In the finned tube heat exchanger that is configured and includes a heat transfer tube through which a refrigerant passes, the plate-like fin has a plurality of slit portions cut and raised in a direction in which the plurality of plate-like fins are stacked. The plurality of slit portions include a first slit group projecting to one surface side of the plate-shaped fin, and a second slit group projecting to the other surface side of the plate-shaped fin, Of the slit portions in the slit group and the second slit group, the protrusion height (Hs1) from the plate-like fin of the slit portion of the first slit group located in the uppermost stream with respect to the gas flow, and the first 1 slit group and 2nd slit group Of the slit portion in, the relationship between the projection height from the plate-like fin slit portion of the second slit unit located second with respect to the flow of gas (Hs2),
1.2 ≦ Hs1 / Hs2 ≦ 1.6
It is comprised so that it may become .

  Another feature of the present invention is that the fin tube heat exchanger configured as described above is mounted on at least one of a ceiling-embedded, ceiling-suspended, or floor-standing air conditioner (indoor unit). It is an air conditioner equipped with a tube heat exchanger.

  ADVANTAGE OF THE INVENTION According to this invention, even when a heat exchanger tube is reduced in diameter and a fin is reduced in size and densified, the fin tube heat exchanger which can suppress the performance fall by a deformation | transformation of a fin shape, and air provided with this A harmony machine can be obtained.

The front view explaining Example 1 of the finned-tube heat exchanger of this invention. The principal part enlarged view which looked at the heat exchanger shown in FIG. 1 from the side surface side. FIG. 2 is an enlarged cross-sectional view of the slit portion shown in FIG. 1, (a) is a cross-sectional view taken along line AA in FIG. 1, (b) is a cross-sectional view taken along line BB in FIG. . The diagram explaining the influence on the performance by the outer diameter D of the heat exchanger tube shown in FIG. The diagram explaining the influence on the performance by row pitch PL of the fin shown in FIG. The diagram explaining the influence on the performance by the step pitch Pt of the fin shown in FIG. The diagram explaining the influence on the performance by the fin pitch Pf shown in FIG. The diagram explaining the influence on the performance by the slit width Ws of the fin shown in FIG. It is a figure explaining the leading edge effect in the slit arrangement | positioning of Example 1 of this invention, (a) is a figure which shows the analysis result of the temperature distribution in the conventional slit arrangement | positioning, (b) is the slit arrangement | positioning of Example 1. The figure which shows the analysis result of temperature distribution. It is a figure explaining the dead water area reduction effect in the slit arrangement | positioning of Example 1 of this invention, (a) is a figure which shows the air flow analysis result in the conventional slit arrangement | positioning, (b) is the air flow in the slit arrangement | positioning of Example 1. FIG. The figure which shows an analysis result, (c) is a perspective view of the (b) figure. The longitudinal cross-sectional view which shows the ceiling embedded type air conditioner provided with the finned-tube heat exchanger shown in FIG. The bottom view which looked at the ceiling-embedded air conditioner shown in FIG. 11 from the lower side. The principal part enlarged front view explaining Example 2 of the finned-tube heat exchanger of this invention. HH sectional drawing of FIG. The principal part enlarged front view explaining Example 3 of the finned-tube heat exchanger of this invention. HH sectional drawing of FIG. The longitudinal cross-sectional view which shows the floor-standing type air conditioner provided with the finned-tube heat exchanger shown in FIG.15 and FIG.16. The longitudinal cross-sectional view which shows the ceiling-suspended type air conditioner provided with the finned-tube heat exchanger shown in FIG.15 and FIG.16. It is a figure which shows Example 4 of the finned-tube heat exchanger of this invention, and is a figure equivalent to FIG.3 (c). FIG. 10 is a diagram for explaining the leading edge effect in the slit arrangement of Example 4, where (a) shows the analysis result of the temperature distribution in the slit arrangement where the central slit 3d is raised, and (b) is the slit arrangement of Example 4. The figure which shows the analysis result of the temperature distribution in. FIG. 6 is a diagram illustrating ventilation resistance in the slit arrangement of Example 4, where (a) is a diagram showing an air flow analysis result in the slit arrangement where the central slit 3d is raised, and (b) is an air flow in the slit arrangement of Example 4. The figure which shows an analysis result. The refrigeration cycle block diagram which shows the example at the time of applying the air conditioner provided with the finned-tube heat exchanger of this invention to a multi-room type air conditioner.

  Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.
1 is a front view for explaining a first embodiment of a finned-tube heat exchanger according to the present invention, FIG. 2 is an enlarged view of a main part of the heat exchanger shown in FIG. 1 viewed from the side (air inflow side), and FIG. 1 is an enlarged cross-sectional view of the slit portion shown in FIG. 1, (a) is a cross-sectional view taken along the line AA in FIG. 1, (b) is a cross-sectional view taken along the line BB in FIG. FIG.

  1 and 2, the fin tube heat exchanger 100 is provided with a plurality of plate-like fins 1 that are provided at predetermined intervals and through which air (gas) passes, and so as to penetrate the plate-like fins 1. A heat transfer tube 2 inserted vertically and meandering, and on the surface of the plate-like fin 1 in the stacking direction of the plate-like fin (a direction substantially perpendicular to the air passage direction). The slit part 3 (3a-3g) is cut and raised.

  As shown in FIG. 2, the heat transfer tube 2 is formed of a plurality of straight tube portions 2s and a curved tube portion 2r connecting the ends of the straight tube portions 2s. As shown in FIG. 1, in this embodiment, the heat transfer tubes 2 are arranged in three rows in the air flow direction (row direction). Further, each of the straight pipe portions 21a, 21b, 21c (the first heat transfer pipe 21) which is a part of the straight pipe portion 2s of the heat transfer pipe 2 is perpendicular to the air flow as shown in FIG. Are arranged in the direction (stage direction), and each straight pipe part 22a, 22b ... (second heat transfer pipe 22) and each straight pipe part 23a, 23b ... (three rows) are also part of the straight pipe part 2s. The heat transfer tubes 23) of the eyes are also arranged in the step direction.

The straight pipe portions 21a, 21b ..., 22a, 22b ..., and 23a, 23b ... are arranged in parallel and staggered. In this embodiment, the outer diameter D of the heat transfer tube 2 is
4mm ≦ D ≦ 6mm
Further, the row pitch PL, which is the interval in the column direction between the axial centers of the straight pipe portions, and the step pitch Pt, which is the interval in the step direction, are in the following ranges. It is configured.

8mm ≦ PL ≦ 10mm
12mm ≦ Pt <14mm
For example, the outer diameter D of the heat transfer tube 2 may be 5 mm, the row pitch PL is 9.4 mm, and the step pitch Pt is 13.89 mm.

  The influence of the heat transfer tube outer diameter D, the step pitch PL, and the step pitch Pt on the performance will be described with reference to FIGS. The performance evaluation described with reference to these figures is based on APF (periodic consumption efficiency) when the finned tube heat exchanger is used as an air conditioner (ceiling embedded indoor unit).

  FIG. 4 is a diagram for explaining the results of investigating the influence of the outer diameter D of the heat transfer tube on the performance. As can be seen from FIG. 4, by reducing the outer diameter D of the heat transfer tube, if the height of the fin tube heat exchanger (the height of the indoor unit) is the same, the number of stages and rows of the heat transfer tubes are increased. The fin efficiency can be improved because the specifications can be reduced in a similar manner in accordance with the outer diameter of the heat transfer tube to increase the density. In addition, by reducing the outer diameter D of the heat transfer tube, it is possible to reduce the dead water area generated on the downstream side of the heat transfer tube, so that the heat transfer rate can be improved and the pressure loss can be reduced. Therefore, when the outer diameter of the heat transfer tube is 5 mm or more, the APF performance is improved as the outer diameter of the heat transfer tube is reduced. On the other hand, if the outer diameter of the heat transfer tube is made smaller than 5 mm, the pressure loss of the refrigerant flowing in the heat transfer tube increases, so the number of refrigerant passages (number of passes) is increased in order to suppress this refrigerant side pressure loss equally. It is necessary to let When the number of refrigerant passages is increased, the step pitch Pt is decreased, and accordingly, the occupied area ratio of the seating surface (flat plate portion) 1a (see FIG. 1) to be secured between the heat transfer tube 2 and the slit portion 3 is increased. The occupied area ratio of the slit portion 3 is relatively lowered. Furthermore, the refrigerant distribution is likely to deteriorate due to an increase in the number of refrigerant passages. For this reason, the APF performance decreases as the heat transfer tube outer diameter is made smaller than 5 mm. Therefore, a peak value of the APF performance appears with respect to the heat transfer tube outer diameter D, and the range in which the performance degradation of the APF is kept within 3% with respect to this performance peak value is as shown in FIG. It is “4 mm ≦ D ≦ 6 mm”, and the heat transfer tube outer diameter D is preferably set within this range.

  FIG. 5 is a diagram for explaining the influence of the fin row pitch PL on the performance. In the range where the row pitch PL is about 9 mm or less, the heat transfer area is increased as the row pitch PL is increased, so that the heat exchange performance is improved, and the distance between the heat transfer tubes 3 between the rows is also increased, so the ventilation resistance is also small. As a result, the APF performance is improved. On the other hand, when the row pitch PL exceeds about 9 mm, the greater the row pitch PL, the longer the length in the row direction and the length of the passage through which the air flows, and between the indoor unit housing and the heat exchanger. Since the passage between them becomes narrow, the ventilation resistance (air side pressure loss) increases. Moreover, since the slit part 3 which exists apart from the heat exchanger tube 2 increases, fin efficiency also falls, APF performance falls. In the APF performance, the operation time is large in a region where the compression function force is small, and an increase in fan power greatly affects the APF performance. Therefore, the peak value of the APF performance with respect to the column pitch PL appears, and the range in which the performance degradation of the APF is kept within 3% with respect to this performance peak value is that the column pitch PL is “8 mm ≦ PL ≦ 10 mm ”, and the row pitch PL may be set within this range.

FIG. 6 is a diagram for explaining the influence of the fin step pitch Pt on the performance. FIG. 6 shows the performance influence of the step pitch Pt. In the range where the step pitch Pt is larger than 13 mm, the number of heat transfer tubes 2 in the step pitch direction decreases as the step pitch Pt increases. In the APF performance, the operation time is large in the region where the compression function force is small, and the operation time when the refrigerant flow rate is small is large. When the flow rate of the refrigerant is small, the flow of the refrigerant in the heat transfer tube does not become a turbulent flow, and the refrigerant flows through the lower portion in the heat transfer tube, so that the amount of heat transferred to the slit portion is reduced. Therefore, as the step pitch Pt of the heat transfer tubes is reduced and the number of heat transfer tubes in the step pitch direction is increased, the inner area of the heat transfer tubes can be increased, and the heat transfer rate and fin efficiency can be improved. Will improve. In addition, in the range where the step pitch Pt is smaller than 13 mm, the ventilation resistance between the heat transfer tubes 2 increases as the step pitch Pt decreases, and between the heat transfer tube 2 and the slit portion 3 as the step pitch Pt decreases. The occupied area ratio of the seating surface 1a (see FIG. 1) to be secured also increases, the occupied area ratio of the slit portion 3 relatively decreases, and stagnation of air generated on the downstream side of the heat transfer tube (dead water area) As the area increases, the APF performance decreases. Accordingly, a peak value of the APF performance appears with respect to the step pitch Pt, and the range in which the performance degradation of the APF is kept within 3% with respect to this performance peak value is that the step pitch Pt is “12 mm ≦ Pt from FIG. <14 mm ”, and the step pitch Pt is preferably set within this range.

  The plate-like fin 1 shown in FIGS. 1 and 2 is a rectangular member, and a plurality of through holes through which the straight pipe portion 2s of the heat transfer tube 2 penetrates are formed in the plate-like fin 1 in a staggered manner. Further, for example, between the straight pipe portion 21a and the straight pipe portion 21b, a first slit group (slit portions 3a, 3c, 3e, 3g) protruding to one surface side of the plate-like fin 1 and the other Second slit groups (slit portions 3b, 3d, 3f) projecting to the surface side are respectively formed (see FIG. 3).

  Each slit portion 3a, 3c, 3e, 3g of the first slit group is obtained by cutting and raising the plate-like fin 1 on one surface side as shown in FIG. Each part is composed of flat portions 32a, 32c, 32e, and 32g, one inclined surface portions 31a, 31c, 31e, and 31g supporting the same, and the other inclined surface portions 33a, 33c, 33e, and 33g. Although only the slit portion 3a is shown in FIG. 5A, the other slit portions 3c, 3e, and 3g are similarly configured.

  As shown in FIG. 3B, the slit portions 3b, 3d, 3f of the second slit group are obtained by cutting and raising the plate-like fin 1 on the other surface side. Each of the plane portions 32b, 32d, and 32f, one slope portions 31b, 31d, and 31f supporting the plane portions 32b, 32d, and 32f, and the other slope portions 33b, 33d, and 33f, respectively. Although only the slit portion 3b is shown in FIG. 5B, the other slit portions 3d and 3f are similarly configured.

FIG. 3C is a cross-sectional view taken along the line HH of FIG. 1 and shows the first slit group (slit portions 3a, 3c, 3e, 3g) and the second slit group (slit portions 3b, 3d, 3f). The configuration is shown. In the figure, Hs1 is the protrusion height from the plate-like fin 1 of the slit portion 3a located in the front row in the first and second slit groups with respect to the air flow (see FIG. (A)), Hs2 Is the protrusion height from the plate-like fin 1 of the slit portion 3b located second in the first and second slit groups with respect to the air flow (see FIG. 5B). The relationship between the heights Hs1 and Hs2 is that the projection height Hs1 of the slit portion 3a located in the front row from the plate-like fin 1 is the projection height Hs2 of the slit portion 3b located second from the plate-like fin 1. To be larger, i.e.
Hs1> Hs2
It is comprised so that. The ratio of the protrusion height (Hs1 / Hs2) is preferably
1.2 ≦ Hs1 / Hs2 ≦ 1.6
It is good to constitute so that.

  With this configuration, the slit 3a disposed immediately after the plate-like fins 1 has a large distance from the plate-like fins 1, and the influence of the temperature boundary layer can be minimized. In addition, even when a shape error of the slit portion occurs, it is possible to minimize the deterioration of the heat exchanger performance. That is, even when the fin shape is deformed by bending or the like during manufacturing of the finned tube heat exchanger, the slit 3a is configured to have a large gap with the plate fin 1, so that even if the slit portion 3a is slightly deformed. The rate of change in the distance from the plate-like fin 1 is slightly suppressed. For this reason, the performance fall of a heat exchanger can also be suppressed to the minimum.

  The reason why the influence of the temperature boundary layer can be minimized by the above-described slit arrangement in this embodiment will be described with reference to FIG. FIGS. 9A and 9B are diagrams corresponding to the HH cross-section of FIG. 1, and are diagrams for explaining the leading edge effect in the slit arrangement in the prior art and the present embodiment. That is, (a) is a diagram showing a temperature distribution analysis result (thermal fluid analysis result explaining the heat transfer performance of the heat exchanger) in the conventional slit arrangement, and (b) is a temperature in the slit arrangement of this embodiment. It is a figure which shows the analysis result (thermal fluid analysis result explaining the heat-transfer performance of a heat exchanger) of distribution.

  In the conventional slit arrangement shown in (a), the protrusion height (cutting height) Hs1 from the plate-like fin 1 of the slit portion 3a located at the most upstream with respect to the gas flow, and the gas flow The protrusion height Hs2 from the plate-like fin 1 of the slit portion 3b located second is equal. In the case of this slit arrangement, on the upstream side of the slit portion 3a, a portion where heat is increased by a front fin (so-called temperature boundary layer) interferes with a portion where the temperature rises in the slit portion 3a (temperature boundary layer). Can be confirmed.

  On the other hand, in the slit arrangement of this embodiment shown in (b), the protrusion height Hs1 from the plate-like fin 1 of the slit portion 3a located in the uppermost stream with respect to the gas flow and the second with respect to the gas flow. The protrusion height Hs2 from the plate-like fin 1 of the slit portion 3b located at is a relationship of “Hs1> Hs2.” In the example of FIG. 5B, the case where “Hs1 / Hs2 = 1.3” is shown as an example.

  (B) As shown in the figure, in the case of the slit arrangement of the present embodiment, on the upstream side of the slit portion 3a located in the uppermost stream, the portion where the temperature is increased by heat exchange with the front fin (temperature boundary layer) However, it is separated from the portion where the temperature rises in the slit portion 3a (temperature boundary layer), and they do not interfere with each other. As a result, fresh air that has not risen in temperature at the front fins easily hits (is easy to contact with) the uppermost slit portion 3a, and further, fresh air hits the downstream slit portions 3b, 3c,. It becomes easy to improve the leading edge effect, and the heat exchange amount of the heat exchanger can be increased.

  FIG. 10 is a view showing an air flow analysis result for explaining the ventilation resistance in the finned tube heat exchanger, and is a view of the heat transfer tube 2 and its peripheral portion as seen from the front side. The dead water area reduction effect in the slit arrangement of this embodiment will be described with reference to FIG. FIG. 10A is a view showing an air flow analysis result in the same conventional slit arrangement (Hs1 = Hs2) as in FIG. 9A, and FIG. 10B is the same slit arrangement of the present embodiment as in FIG. 9B. The figure which shows the air flow analysis result in (Hs1 / Hs2 = 1.3), (c) is a perspective view of (b) figure.

10 (a) and 10 (b) are compared with each other in the air flow distribution of the present embodiment shown in FIG. 10 (b), compared with the conventional air flow distribution shown in FIG. 10 (a). It turns out that the part (dead water area) where the speed produced on the side is slow is decreasing.
The dead water area reduction effect in the present embodiment will be described in an easy-to-understand manner with a perspective view shown in FIG. In the present embodiment, the height (Hs1) of each of the slope portions 31a, 31c, 31e, 31g where the slit portions 3a, 3c, 3e, 3g are raised is formed larger than the conventional one shown in FIG. ing. Therefore, among these slope portions, the slope portions 31e and 31g on the wake side have a larger function of guiding the airflow from the upstream side to the rear side of the heat transfer tube 2 than the conventional one. By this function, the effect of reducing the dead water area (slow part; stagnation) generated on the downstream side of the heat transfer tube 2 can be obtained, and the ventilation resistance can be reduced by the effect of reducing the dead water area, thereby improving the heat transfer efficiency. Can also be planned.

  Therefore, according to the present embodiment, it is possible to obtain a high-density and high-efficiency heat exchanger by reducing the diameter of the heat transfer tube and reducing the step pitch, row pitch, fin pitch, etc. A finned tube heat exchanger that can minimize variations can be obtained.

FIG. 7 is a diagram for explaining the influence of the fin pitch Pf shown in FIG. 2 on the performance. In the range where the fin pitch Pf is larger than 1.25 mm, the smaller the fin pitch Pf, the larger the number of fins, the larger the heat transfer area of the fins, and the smaller the representative dimension (outer diameter of the heat exchanger). The APF performance is improved by improving the heat transfer coefficient. On the other hand, when the fin pitch Pf is made smaller than 1.25 mm, the ventilation resistance increases, the air-side pressure loss increases, and the influence of the temperature boundary layer increases, so the APF performance decreases. In order to suppress the performance degradation within 3% from the performance peak, the fin pitch Pf is set to
1.0mm ≦ Pf ≦ 1.5mm
It is preferable to set in the range.
In FIG. 2, Tf is the thickness of the finned tube heat exchanger 1, and a thickness of about 0.1 mm is usually used.

FIG. 8 is a diagram for explaining the influence on the performance by the width (slit width) Ws of each slit portion in the plate-like fin 1 shown in FIG. 1 and FIG. In the range where the slit width Ws is larger than 1.1 mm, the heat transfer coefficient can be increased and the APF performance can be improved by increasing the number of the slit portions 3 as the slit width Ws is reduced. That is, as the slit width Ws is reduced, the heat transfer promotion effect (leading edge effect) due to the update of the temperature boundary layer at the leading edge of the slit portion 3 increases, and thus the heat transfer coefficient increases. On the other hand, in the range where the slit width Ws is smaller than 1.1 mm, the air flow tends to be turbulent as the slit width Ws is reduced, and the ventilation resistance (air side pressure loss) increases, and the upstream side slit portion. Since the effect of the temperature boundary layer appears in the slit portion on the downstream side, the fin efficiency is lowered, and thus the APF performance is lowered. In order to suppress the performance degradation within 3% from the peak of performance, the slit width should be
0.8mm ≦ Ws ≦ 1.4mm
It is preferable to set in the range.

  11 is a longitudinal sectional view showing a ceiling-embedded air conditioner (indoor unit) in a state where the finned tube heat exchanger shown in FIG. 1 is mounted, and FIG. 12 shows the ceiling-embedded air conditioner shown in FIG. It is the bottom view seen from the lower side.

  In the figure, 50 is a ceiling-embedded air conditioner (indoor unit), 51 is a casing embedded in the ceiling 70, and inside the casing 51 is a finned tube heat exchanger 100 shown in FIG. Is installed so as to surround the fan 52. The blower 52 is rotated by an electric motor 53, and the room air is sucked from the suction filter 54 by the rotation of the blower 52, passes through the blower 52, and is disposed around the blower as shown by the arrows in FIG. It passes through the exchanger 100 and is bent and blown in an arbitrary direction by the wind direction guide 55. In FIG. 11, reference numeral 56 denotes a drain pan provided at the lower portion of the heat exchanger 100.

The air conditioner 50 adjusts the sucked indoor air to a predetermined temperature by the heat exchanger 100 and blows it out into the room to perform air conditioning.
In the ceiling-embedded air conditioner, the intervals between the blower 52 and the heat exchanger 100 and between the heat exchanger 100 and the casing 51 are narrow, and it is necessary to achieve high efficiency while maintaining compactness. . The finned tube heat exchanger 100 of the present embodiment shown in FIG. 1 can be miniaturized by increasing the density of the heat exchanger, so that the effect applied to the ceiling-embedded air conditioner is great.

  Moreover, as shown in FIG. 12, since the finned-tube heat exchanger 100 installed in the ceiling-embedded air conditioner is arranged around the blower 52, the heat exchanger 100 can be bent at a plurality of locations. Has been made. For this reason, a slight fin-shaped deformation tends to occur during bending. In particular, the slit portion 3a on the most upstream side of each fin is in contact with a die or the like during bending and easily receives an external force and is easily deformed. In this embodiment, the protrusion height Hs1 of the most upstream slit portion 3a is increased. Since it comprises, even if the slit part 3a receives external force and deform | transforms, the performance degradation by fin deformation | transformation can be suppressed to the minimum. Therefore, the APF performance of the air conditioner can be improved by using the air conditioner including the finned tube heat exchanger of the present embodiment.

  A finned tube heat exchanger according to a second embodiment of the present invention will be described with reference to FIGS. 13 and 14. FIG. 13 is an enlarged front view of the main part of the finned tube heat exchanger, and FIG. 14 is a cross-sectional view taken along line HH in FIG. In these drawings, the portions denoted by the same reference numerals as those in FIGS. 1 to 3 indicate the same or corresponding portions.

  The finned tube heat exchanger 100 (see FIG. 1) is provided with a plurality of plate-like fins 1 through which air passes with a predetermined interval therebetween, and is inserted vertically into the plate-like fins 1 and meanders. The plate-like fin 1 has a slit portion 3 (3a to 3g) cut and raised. As shown in FIG. 14, a first slit group (slit portions 3 a, 3 c, 3 e, 3 g) is provided on one surface side of the plate-like fin 1, and a second slit group (on the other surface side of the plate-like fin 1 ( Slit portions 3b, 3d, 3f) are formed.

  Also in the present embodiment, as in the first embodiment, the protruding height Hs1 (Hsa) of the most upstream slit portion 3a is higher than the protruding height Hs2 (Hsb) of the second slit portion 3b from the upstream side. Preferably, “1.2 ≦ Hs1 / Hs2 ≦ 1.6” is satisfied. Furthermore, in the present embodiment, in both the first slit group and the second slit group, the protruding height of each slit portion from the plate-like fin 1 is higher as the slit portion is located outward from the fin center line c. It is comprised so that it may become. That is, in the first slit group, the projecting heights Hsa and Hsg of the outer slit parts 3a and 3g are made higher than the projecting heights Hsc and Hse of the center-side slit parts 3c and 3e, and the second slit group is similarly configured. The protrusion heights Hsb and Hsf of the outer slit portions 3b and 3f are higher than the protrusion height Hsd of the central slit 3d. Moreover, the height of each slit part is comprised so that it may become left-right symmetric with respect to the row direction centerline c of a fin, and it is also possible to use a fin upside down.

  Further, in the present embodiment, the rising positions of the rising inclined portions 31a to 31g (only the rising inclined portions 31f and 31g are indicated by symbols in FIG. 13) of the slit portions 3a to 3g are arranged concentrically in the heat transfer tube 2. It is composed.

  By configuring in this way, the rising slopes 31f and 31g of the slits 3f and 3g on the wake side serve as air guide walls, so that a dead water area (air and vortex) generated on the wake side of the heat transfer tube 2 can be obtained. Stagnation part) can be efficiently reduced on both sides of the plate-like fins. As a result, ventilation resistance can be further reduced and heat transfer coefficient can be further improved, improving heat exchanger performance. it can.

  A fin tube heat exchanger according to a third embodiment of the present invention will be described with reference to FIGS. 15 and 16, and an application example of the fin tube heat exchanger according to the third embodiment will be described with reference to FIGS.

  15 is an enlarged front view of the main part of the finned tube heat exchanger, and FIG. 16 is a cross-sectional view taken along the line HH of FIG.

  15 and FIG. 16, the rib-shaped ribs 4a in the vicinity of the end portions in the row direction of the plate-like fins 1 are compared to the fin-tube heat exchanger of the first embodiment described with reference to FIGS. 4b is provided. Each of the ribs 4a and 4b is formed continuously in the step direction of the plate-like fin 1, and the plate-like fin 1 is configured to be highly efficient and have a long length in the step direction by reducing the diameter of the heat transfer tube and increasing the density of the fin. The bending rigidity of can be improved. As a result, it is possible to prevent fin deformation such as twisting and bending at the time of manufacturing the heat exchanger, improve production efficiency and quality, and can be widely applied to different types of air conditioners such as floor standing type and ceiling hanging type. Become. Other configurations are the same as those shown in FIGS. 1 to 3, and the same effects as those shown in FIGS. 1 to 3 can be obtained.

  In the ceiling-embedded air conditioner shown in FIGS. 11 and 12 described above, the height of the product cannot be increased so much due to the limitation of the height of the ceiling behind the ceiling. Therefore, the height in the step direction of the fin tube heat exchanger incorporated therein is relatively small, for example, about 250 mm. Therefore, deformation in the fin longitudinal direction at the time of manufacturing the plate-like fins 1 hardly occurs. However, when the finned tube heat exchanger 100 is mounted on a product having a relatively large product height such as a floor-standing type air conditioner as shown in FIG. 17, the height in the step direction of the heat exchanger is, for example, 840 mm. It becomes large and becomes easy to produce the longitudinal direction deformation at the time of plate-like fin manufacture. On the other hand, since the rigidity of the heat exchanger can be improved by adopting the finned tube heat exchanger having the plate-like fins 1 shown in FIGS. 15 and 16, the quality of the floor-standing air conditioner is improved. And the effect which can improve production efficiency is acquired.

  Note that, in FIG. 17, the parts denoted by the same reference numerals as those in FIG. 11 indicate the same or corresponding parts and have the same functions, and thus description thereof is omitted. Also in this embodiment, even if the slit portion 3a on the most upstream side of the fin is deformed at the time of assembling the air conditioner, the performance deterioration due to the fin deformation can be minimized.

  FIG. 18 is a longitudinal sectional view showing a ceiling-suspended air conditioner equipped with the finned tube heat exchanger shown in FIGS. 15 and 16. This ceiling-suspended air conditioner is designed to be exposed from the ceiling surface, and it is required to reduce the height of the product from the consideration of suppressing the feeling of pressure. In order to secure the area of the heat exchanger The heat exchanger 100 needs to have a relatively large inclination angle θ with respect to the vertical direction.

  Further, as in the ceiling-embedded air conditioner shown in FIGS. 11 and 12, the heat exchanger 100 has a planar shape because it is not bent in the longitudinal direction of the heat transfer tube 2. Therefore, it is difficult to ensure the rigidity of the heat exchanger 100. In the finned-tube heat exchanger according to the third embodiment shown in FIGS. 15 and 16, it is easy to ensure the rigidity of the heat exchanger 100 even when the heat transfer tubes 2 are reduced in diameter and the row pitch PL is reduced. By adopting this heat exchanger in the ceiling-suspended air conditioner shown in FIG. 16, it is possible to obtain an air conditioner that achieves both high efficiency and product reliability.

  In FIG. 18, the same reference numerals as those in FIG. 11 denote the same or corresponding parts, which have the same functions, and thus the description thereof is omitted. Also in this embodiment, even if the slit portion 3a on the most upstream side of the fin is deformed at the time of assembling the air conditioner, the performance deterioration due to the fin deformation can be minimized.

  Thus, by using the finned-tube heat exchanger shown in Example 3, it becomes possible to apply to various forms of air conditioners, and it becomes possible to further increase the efficiency of the air conditioners.

A fin tube heat exchanger according to a fourth embodiment of the present invention will be described with reference to FIGS. In these drawings, the portions denoted by the same reference numerals as those in FIGS. 1 to 3 indicate the same or corresponding portions.
FIG. 19 is a view showing Example 4 of the finned-tube heat exchanger of the present invention and is a view corresponding to FIG. 3C (a view corresponding to the HH cross section in FIG. 1).

  In this embodiment, as shown in FIG. 19, with respect to the slit arrangement in the first embodiment shown in FIG. 3C, the slit portion (center slit portion) located at the center in the column direction (air flow direction). 3d is not raised, and is the same height as the substrate surface of the plate-like fin 1. Other configurations are the same as those of the first embodiment shown in FIG.

  FIG. 20 is a diagram for explaining the leading edge effect at each slit portion in the slit arrangement of the embodiment 4 shown in FIG. 19, and (a) is an analysis result of the temperature distribution in the slit arrangement where the central slit portion 3d is raised. (B) is a figure which shows the analysis result of the temperature distribution in the slit arrangement | positioning of Example 4. FIG.

  As shown in FIG. 20A, when the center slit portion 3d is raised, interference between the upstream slit portion 3b and the downstream slit portion 3f and the temperature boundary layer is likely to occur. On the other hand, as shown in FIG. 5B, when the center slit portion 3d is not raised (that is, when the rise height is zero and no rise is performed), the center slit portion 3d The first slit portion 3b and the downstream slit portion 3f are displaced from each other, so that interference with the temperature boundary layers of the upstream and downstream slit portions 3b and 3f is reduced. Heat transfer performance can be further improved compared to the above.

  21A and 21B are diagrams for explaining the ventilation resistance in the slit arrangement of the fourth embodiment. FIG. 21A is a diagram showing the air flow analysis result in the slit arrangement in which the central slit 3d is raised, and FIG. 21B is the slit arrangement of the fourth embodiment. It is a figure which shows the air flow analysis result in.

As shown in FIG. 21 (a), in the case of the slit arrangement in which the central slit 3d is raised, the airflow passes through the slits at a high speed by repeating a small meander, and this fast flow is in front of each slit portion. It will flow without sufficient contact with the edges.
On the other hand, in the case of the present embodiment shown in FIG. 21B (in the case where the central slit 3d is not raised), the air flow greatly meanders and flows. As a result, although the airflow resistance is slightly increased in the slit arrangement in (b) compared with the slit arrangement in (a), the passage for allowing the airflow to pass through is ensured as a whole. The part where the flow rate is particularly fast increases. In addition, fresher air that has not undergone heat exchange can easily come into contact with the slit portions. For these reasons, in this embodiment, heat transfer performance can be improved more than the rate of increase in ventilation resistance, and a high-performance fin tube heat exchanger can be obtained.

FIG. 22 is a refrigeration cycle configuration diagram illustrating an example in which the above-described air conditioner including the finned tube heat exchanger of the present invention is applied to a multi-room air conditioner.
There is a so-called multi-room air conditioner in which a plurality of indoor units are connected to a single refrigeration cycle. This multi-room air conditioner is a refrigerant circulated from the outdoor unit 60 (for example, a single refrigerant such as R410A, R32, R407C, R404A, R744, R161, R290, R134a, R152a, HFO1234yf, or a mixed refrigerant thereof) ) Are circulated through the plurality of indoor units 50a, 50b,... Connected to each other by a necessary amount, and variable refrigerant pressure reducing mechanisms (electronic expansion valves) 9a, 9b,. Is. In such a multi-room type air conditioner, a plurality of indoor units 50a, 50b,... Connected are designed so that various forms and capacities are selected. Therefore, a transitional change is larger than that of an air conditioner in which only one indoor unit is connected to one outdoor unit, and the heat exchanger 100 has higher performance and reliability. Required.

  Therefore, by adopting the finned tube heat exchanger of the present invention as described in FIGS. 1 to 21 and an air conditioner (indoor unit) equipped with the same to a multi-room air conditioner, the compact and High performance and high reliability can be stably obtained, and it is possible to exhibit the high performance required for a multi-room type air conditioner having an indoor unit equipped with a refrigerant variable pressure reducing mechanism.

  In FIG. 22, 6a and 6b are compressors provided in the outdoor unit 60, and the refrigerant discharged from the compressors 6a and 6b is the oil separator 7, the four-way valve 8, the outdoor heat exchanger 101, and the outdoor expansion. Flows through the valve (electronic expansion valve) 9 and the liquid receiver 10 to the indoor unit 50 (50a, 50b,...) Side. Further, the refrigerant from the indoor unit 50 side passes through the four-way valve 8 and the accumulator 5 and is again sucked into the compressors 6a and 6b. 13 is a high / low pressure bypass circuit for connecting the discharge side and the suction side of the compressors 6a, 6b, and 14 is an open / close valve for opening / closing the high / low pressure bypass circuit. When the discharge side pressure of the compressor rises too much The opening / closing valve 14 is opened when it is desired to raise the discharge temperature quickly by increasing the temperature on the compressor suction side, such as during startup. Reference numeral 102 denotes a blower for supplying outside air to the outdoor heat exchanger 101. The indoor units 50a, 50b,... Are also provided with fin tube heat exchangers 100a, 100b,. For the fin tube heat exchangers 100a, 100b,..., For example, those described in any of the first to fourth embodiments of the present invention are used.

As described above, according to the present embodiment, even if the heat transfer tube is reduced in diameter and the fins are downsized and densified by reducing the step pitch, row pitch, fin pitch, etc., the heat transfer performance. Can be improved and an increase in ventilation resistance can be suppressed, and a high-performance fin tube heat exchanger can be obtained.
Also, even when fins are deformed due to external forces during manufacture of fin-tube heat exchangers or when they are installed in air conditioners, etc., even if dimensional errors occur, heat exchanger efficiency is reduced and heat is reduced. Variations in exchange performance can be minimized.
Furthermore, it is possible to further improve the efficiency and reliability of the air conditioner by applying the finned tube heat exchanger of each embodiment of the present invention described above to various types of air conditioners. .

1: plate-like fin, 1a: seating surface (flat plate part),
2, 21 (21a-21c), 22 (22a, 22b), 23 (23a-23c): heat transfer tube, 2s: straight tube portion, 2r: bent tube portion,
3 (3a-3g): slit part (31a, 31b, 33a, 33b: slope part, 32a, 32b: plane part),
4 (4a, 4b): rib,
5: Accumulator, 6a, 6b: Compressor, 7: Oil separator, 8: Four-way valve, 9: Outdoor expansion valve, 9a, 9b: Refrigerant variable decompression mechanism, 10: Liquid receiver,
13: High / low pressure bypass circuit, 14: On-off valve,
50 (50a, 50b): air conditioner (indoor unit), 51: housing, 52 (52a, 52b): blower, 53: electric motor, 54: suction filter, 55: wind direction guide, 56: drain pan,
60: outdoor unit,
70: Ceiling,
100 (100a, 100b): fin tube heat exchanger,
101: Outdoor heat exchanger, 102: Blower.

Claims (17)

A plurality of plate-like fins arranged so as to allow gas to pass through each other at predetermined intervals, and a heat transfer tube configured to penetrate and meander through the plate-like fins, and through which the refrigerant passes; In a finned tube heat exchanger with
The plate fin includes a plurality of slit portions cut and raised in a direction in which a plurality of the plate fins are stacked,
The plurality of slit portions include a first slit group projecting to one surface side of the plate-shaped fin, and a second slit group projecting to the other surface side of the plate-shaped fin,
Of the slit portions in the first slit group and the second slit group, the protrusion height (Hs1) from the plate-like fin of the slit portion of the first slit group located on the most upstream side with respect to the gas flow ; The protrusion height (Hs2) from the plate-like fin of the slit portion of the second slit group located second with respect to the gas flow among the slit portions in the first slit group and the second slit group Relationship with
1.2 ≦ Hs1 / Hs2 ≦ 1.6
It is comprised so that it may become . The fin tube heat exchanger characterized by the above-mentioned . 2. The finned tube heat exchanger according to claim 1 , wherein the height of the slit portion constituting the first slit group is the same, and the height of the slit portion constituting the second slit group is also the same. A finned-tube heat exchanger characterized by being configured to a height. 2. The fin tube heat exchanger according to claim 1 , wherein the slit portion located at the uppermost stream with respect to the gas flow has a protruding height (Hs1) from the plate-like fin and the second with respect to the gas flow. The relationship between the height (Hs2) protruding from the plate-like fin of the slit portion located at
Hs1 / Hs2 = 1.3
It is comprised so that it may become. The fin tube heat exchanger characterized by the above-mentioned. The fin tube heat exchanger according to claim 1 , wherein among the plurality of slit portions cut and raised in the laminating direction of the plate-like fins, a rising height of a central slit portion positioned at the fin row direction center is set. A finned-tube heat exchanger characterized by zero (no startup). The finned-tube heat exchanger according to claim 1 , wherein an outer diameter (D) of the heat transfer tube is 4 to 6 mm. 6. The finned tube heat exchanger according to claim 5 , wherein the plurality of plate-like fins have a straight pipe portion of the heat transfer tube configured to meander in a step direction (longitudinal direction) of the plate-like fins. A step pitch Pt, which is penetrated into a plurality of stages at equal intervals, and is an interval in the step direction of each straight pipe portion,
12mm ≦ Pt <14mm
A finned-tube heat exchanger characterized by being configured to be in the range. The finned tube heat exchanger according to claim 6 , wherein a plurality of rows of fins composed of the plurality of plate-like fins are provided in the gas flow direction, and a space between the straight tube portions of the heat transfer tubes in each row. The row pitch PL is
8mm ≦ PL ≦ 10mm
A finned-tube heat exchanger characterized by being configured to be in the range. In the finned-tube heat exchanger of Claim 7 , The width (Ws) of each said slit part was 0.8-1.4mm, and the fin pitch (Pf) was 1.0-1.5mm, It is characterized by the above-mentioned. Fin tube heat exchanger.   2. The fin tube heat exchanger according to claim 1, wherein protrusion heights from the plate fins of the plurality of slit portions cut and raised in the stacking direction of the plate fins are outward from the fin row direction center line. The finned tube heat exchanger is configured to be higher as the slit portion is positioned, and the rising positions of the rising inclined portions of the slit portions are arranged concentrically in the heat transfer tube.   The fin tube heat exchanger according to claim 1, wherein protrusion heights from the plate-like fins of the plurality of slit portions cut and raised in the laminating direction of the plate-like fins with respect to the fin row direction center line. A finned tube heat exchanger configured to be symmetrical.   The finned tube heat exchanger according to claim 1, wherein chevron-shaped ribs are formed in the vicinity of both end portions in the row direction of the plate-like fins. The finned tube heat exchanger according to claim 7 , wherein the fin rows are provided in three rows in the gas flow direction, and the straight pipe portion of the heat transfer tube passing through the fins in each row is in the gas flow direction. A finned tube heat exchanger characterized by being arranged in a staggered pattern in three rows.   The air conditioner provided with a finned tube heat exchanger, wherein the air conditioner is a ceiling-embedded air conditioner, and the finned tube heat exchanger is the finned tube heat exchanger according to claim 1. An air conditioner equipped with a finned tube heat exchanger. The air conditioner provided with a finned tube heat exchanger, wherein the air conditioner is a ceiling-suspended type or floor-standing type air conditioner, and the finned tube heat exchanger is a finned tube heat exchanger according to claim 11. An air conditioner equipped with a finned-tube heat exchanger. The air conditioner provided with the finned-tube heat exchanger according to claim 13 , wherein the ceiling-embedded air conditioner includes a refrigerant variable pressure reducing mechanism for flowing a necessary amount of refrigerant. Air conditioner with finned tube heat exchanger. The air conditioner provided with the finned tube heat exchanger according to claim 15 , wherein the air conditioner is a multi-room type air conditioner in which a plurality of indoor units are connected to a single refrigeration cycle. An air conditioner equipped with a finned tube heat exchanger, wherein at least a part of the plurality of indoor units is a ceiling-embedded air conditioner (indoor unit). The air conditioner provided with the finned-tube heat exchanger according to claim 14 , wherein the air conditioner includes a refrigerant variable pressure reducing mechanism for flowing a necessary amount of refrigerant, and the air conditioner is a single refrigeration unit. A multi-room type air conditioner in which a plurality of indoor units are connected to a cycle, wherein at least a part of the plurality of indoor units is a ceiling-suspended type or floor-standing type air conditioner (indoor unit) An air conditioner equipped with a finned tube heat exchanger.

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