JPH06123587A - Heat exchanger - Google Patents

Abstract

PURPOSE:To enable effective prevention of frosting by a method wherein the ratio between the width in the direction of draft of the part of a radiator fin provided with a heat exchanger pipe and the overall width in the direction of draft of the radiator fin is set in a specified range. CONSTITUTION:A plurality of heat exchanger pipes 1 are stacked in a plurality of layers in the same direction in a state of being parallel to the direction (a) of draft by a strip-plate-shaped radiator fin 5 being long in the direction of height. The ratio between the overall width W2 of this radiator fin 5 and the width of the part of the radiator fin 5 provided with the heat exchanger pipe 1 is set to be W2/W1=1.2 to 1.9. Since the windward-side end part 5a is continuous in the vertical direction according to this constitution, a drain condensing on the surface of the radiator fin 5 is discharged easily onto the lower side of the radiator fin 5 through this end part before frosting on this part. Therefore the frosting can be prevented effectively and the capacity of heat exchange can be maintained excellently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger incorporated in an outdoor unit of an air conditioner, for example.

[0002]

2. Description of the Related Art In recent years, so-called parallel flow type heat exchangers using flat tubes having higher heat exchange efficiency have been researched in order to improve the performance of air conditioners (air conditioners) and to make them compact.

Generally, however, as in automobiles and the like, band-shaped radiating fins are bent in a zigzag shape, and the fins are sandwiched between opposed faces of flat tubes arranged in parallel. Many are manufactured by attaching.

[0004]

The conventional general parallel flow type heat exchanger has the following problems to be solved.

That is, when this heat exchanger is used as an outdoor heat exchanger and the heating operation is performed, the drain generated on the radiating fins may be frozen and frosted. In particular,
Although the frost is likely to form on the windward side where the air first collides, if this frost develops, the introduction of air may be hindered and the heat exchange performance may be significantly reduced.

The present invention has been made in view of such circumstances, and an object thereof is to provide a parallel flow type heat exchanger capable of effectively preventing frost formation. .

[0007]

A first means of the present invention is a flat heat exchange pipe which is arranged in a width direction substantially in parallel with a ventilation direction and through which a heat exchange medium flows, and a leeward direction. And a strip plate-shaped heat radiation fin that is combined in a state orthogonal to the heat exchange pipe by inserting the heat exchange pipe into the insertion hole having an opening hole on the side,
Width w _{1 in} the ventilation direction of the portion of the radiating fin where the heat exchange pipe is provided and the total width w of the radiating fin in the ventilation direction
₂ of the ratio w ₂ / w ₁ is characterized in that it has a 1.2 to 1.9.

A second means is the same as the first means,
A regulating member that abuts on the other surface of the adjacent fins and that regulates the interval between the adjacent fins is provided on one surface of the radiator fin in a protruding manner.

[0009]

With this structure, it is possible to prevent frost formation on the windward end of the heat radiation fin in the ventilation direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is an overall view of the heat exchanger of the present invention. This heat exchanger is used as an outdoor heat exchanger, for example.

In the figure, reference numeral 1 is a heat exchange pipe. The heat exchange pipe 1 has a flat shape, and the inside is partitioned to form a plurality of passages 1a. The heat exchange pipes 1 are arranged so that the width direction thereof is substantially horizontal, and a plurality of heat exchange pipes 1 are provided in parallel in the vertical direction orthogonal to the ventilation direction shown by the arrow (a) in the figure.

The heat exchange pipe 1 is bent in a substantially U shape in a horizontal plane, and both ends thereof are connected to the side surfaces of the first and second headers 2 and 3 which are provided upright. That is,
The refrigerant is first supplied to the first and second headers 2 and 3, respectively, and is branched from the first and second headers 2 and 3 to each heat exchange pipe 1.

Further, a plurality of strip-shaped radiating fins 5 elongated in the height direction are laminated in the plurality of heat exchange pipes 1 ... In the same direction in a direction parallel to the ventilation direction (a). Are combined. Next, the structure of the radiation fin 5 will be described with reference to FIG.

The heat radiation fin 5 is a strip-shaped thin plate made of aluminum having a thickness of about 0.2 mm. A plurality of insertion holes 6 ... Into which the heat radiation fins 5 are inserted are formed in the heat radiation fins 5 along the longitudinal direction at intervals e where the heat exchange pipes 1 are provided.

The insertion holes 6 are opened at one end on the leeward side in the ventilation direction of the radiating fins 1, and the heat exchange pipe 1 is inserted from this opening side as shown by the arrow (b) in the figure. ing. Therefore, a plurality of heat radiation fins 1 are laminated and held in the same direction, and the heat exchange pipes 5 are inserted into the insertion holes 6 so that the heat radiation fins 5 and the heat exchange pipes 1 as shown in FIG. Are combined. The peripheral portion of the insertion hole 6 is raised as shown in FIGS. 1A and 1B to form a holding piece 7 for holding the outer peripheral surface of the heat exchange pipe 1.

On the other hand, a plurality of slits 8 ... Along the longitudinal direction of the heat radiation fin 5 are provided between adjacent insertion holes 6 at predetermined intervals. The fin portions 9 divided by the slits 8 ... Are molded so as to alternately project to the opposite side, as shown in FIG. This allows
Air is effectively contacted with the fins 9 to improve the heat exchange performance.

In addition, a reference numeral 10 in the drawing is a gap regulation portion (regulation member) which is raised on one surface side of the radiation fins 5 to regulate the distance between the adjacent radiation fins 5. Even when the radiation fins 5 are stacked, the regulation portion 10 regulates the radiation fins 5 so that the adjacent radiation fins 5 are not in contact with each other and a constant space is always maintained.

Further, the overall width w ₂ of the radiation fin 5 and the width of the radiation fin 5 where the heat exchange pipe 1 is provided (the range where the slit 8 is provided from the leeward end of the radiation fin 5) w _1. the ratio of is formed such that w ₂ / w ₁ = 1.2~1.9. That is, the windward end portion 5a of the radiating fin 5 is provided so as to extend a predetermined amount to the windward side from the windward end of the heat exchange pipe 1.

Next, as described above, the reason why the windward end portion 5a of the radiation fin 5 is extended from the heat exchange pipe 1 by a predetermined width and w ₂ / w ₁ = 1.2 to 1.9 is set. Will be described. First, the reason for extending the windward end 5a from the heat exchange pipe 1 by a predetermined width is as follows.

That is, since the heat exchanger on the outdoor side is used as an evaporator, the water vapor cooled on the surface of the radiating fins 5 is condensed to generate drainage. But,
Since the windward end 5a is continuous in the vertical direction, the drain condensed on the surface of the radiation fin 1 is likely to be discharged to the lower side of the radiation fin 1 through this portion before frost is formed there. Therefore, it is effective in preventing frost formation.

Further, the radiation fin 1 with which the outside air comes into contact first
Drain is particularly likely to occur at the windward end of the. As shown in FIG. 3, if the width of the windward end 5a 'is narrow,
As shown in FIG. 3A, the generated drain is frosted on the windward end portion 5a ', which hinders ventilation.

However, as in the present invention, the windward end 5a is
When the width of the heat exchange pipe 1 is increased, the temperature of this portion becomes higher than the temperature of the heat exchange pipe 1. Therefore, it is less likely that frost will be concentrated on this portion, and the frost will be averaged over the entire width of the radiation fin 5. By this,
It is considered that the wind can effectively pass between the radiating fins 5 and the ventilation resistance does not decrease and the heat exchanging ability is maintained. Next, the result of an experiment conducted to determine this ratio w ₂ / w ₁ will be described.

The air conditioners used in the experiments had a rated heating capacity of 4.2 kW and a 2 ° C. rated heating capacity of 4.2.
With KW, the above w ₁ is fixed to 16 mm, and the radiation fins 5 have a stacking pitch of 1.2 mm.

In the graphs shown in FIGS. 4 (a) and 4 (b), the vertical axis represents the heating capacity ratio when the heating capacity when w ₂ / w ₁ = 1.15 is 100%, and the horizontal axis represents the heating capacity ratio. The ratio is w ₂ / w ₁ .

In the vicinity of w ₂ / w ₁ = 1.15, the amount of extension of the windward end portion 5a is small, so the temperature of this portion is low, not much different from the temperature of the heat exchange pipe 1. For this reason, frost is generated in this amount, and ventilation is hindered, so the heating capacity is not very good. Further, in the vicinity of w ₂ / w ₁ = 2.0, the total width w ₂ of the radiation fin 5 becomes large (32 m
However, the ventilation resistance increases and the heating capacity decreases.

On the other hand, in the vicinity of w ₂ / w ₁ = 1.2 to 1.9, there is no such a defect, the increase in area of the radiation fins 5 effectively works for heat exchange, and the windward end portion 5 a of the windward end portion 5 a. Since the temperature becomes higher than that of the heat exchange pipe 1, the frost is not concentrated in this portion and becomes uniform. As a result, the heating capacity is improved. Note that this measurement is the result of adjusting the air flow rate so that the noise becomes constant. Therefore, the same result can be obtained when it is actually used.

However, as shown in FIG. 5, when the increase of the heat transfer coefficient on the air side and the increase of the ventilation resistance are investigated, it is economically w ₂
It is better to keep / w ₁ = 1.2 to 1.6. Such a configuration has the following effects. First, as described above, as a result of being able to prevent frost from concentrating on the windward end portion, there is an effect that a heat exchanger having a high heat exchange capacity can be obtained.

Secondly, the fins 9 are formed by providing the slits 8 in the central portion of the heat radiation fin 5 whose absolute humidity of the wind is lower than that of the windward end 5a. Since it is less likely to form frost on the radiating fin 9, the performance of the heat radiating fin 5 can be kept good.

Third, when the heat exchanger is bent into a U-shape as shown in FIG. 2, the heat exchange pipes 1 ...
Since the heat dissipating fins are arranged, it is less likely that the radiating fins 5 will be broken by the bending jig during bending. Fourthly, since the space regulating portion 10 is provided on the radiating fins 5 in a protruding manner, it is possible to prevent the adjacent radiating fins 5 and 5 from coming into contact with each other and maintain the heat exchange performance. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without changing the gist of the invention.

For example, in the above-mentioned one embodiment, the windward end portion 5a has a flat shape, but it is shown in FIGS.
As shown by ″, it may be formed in a wavy shape.
According to such a configuration, especially when the passing air is moist air, the drain can be effectively discharged to the lower side of the radiation fin 10, which is effective.

[0031]

As described above, according to the first aspect of the present invention, the flat heat exchange pipe is disposed in the width direction substantially in parallel with the ventilation direction, and the heat exchange medium is circulated inside the ventilation pipe. A strip plate-shaped heat radiating fin which is combined in a state orthogonal to the heat exchange pipe by inserting the heat exchange pipe into the insertion hole. those where the ratio w ₂ / w ₁ ventilation direction of the total width w ₂ of width w ₁ and the radiating fins of the ventilation direction of the portion in which the heat exchange pipe is provided as 1.2 to 1.9.

The second structure is the same as the first structure.
On one surface of the radiating fins, a regulating member that abuts on the other surface of the adjacent radiating fins and regulates the interval between the adjacent fins is provided in a protruding manner.

According to such a structure, firstly, since it is possible to effectively prevent the frost from being concentrated on the windward end of the radiation fin, it is possible to maintain the heat exchange capacity without obstructing ventilation. There is an effect that can be. Further, since the adjacent heat radiation fins are prevented from coming into contact with each other, there is an effect that the heat exchange capacity can be maintained.

[Brief description of drawings]

FIG. 1A is a side view showing an essential part of an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line I-I.

FIG. 2 is likewise an overall perspective view.

FIG. 3 is an explanatory view for explaining frost formation.

FIG. 4A is a graph showing experimental results of 2 ° C. heating capacity, and FIG. 4B is a graph showing experimental results of rated heating capacity.

FIG. 5A is a graph showing an increase in air-side heat transfer coefficient, and FIG. 5B is a graph showing an increase in ventilation resistance.

FIG. 6A is a side view showing another embodiment, and FIG.
Is also a cross-sectional view taken along line VI-VI.

[Explanation of symbols]

1 ... Heat exchange pipe, 5 ... Radiating fin, (a) ... Ventilation direction.

Claims (2)

[Claims] 1. A flat heat exchange pipe, which is arranged in the width direction substantially parallel to the ventilation direction and through which a heat exchange medium flows, and an insertion hole which is open to the leeward side in the ventilation direction. The heat exchange pipe is inserted into the heat exchange pipe so as to be orthogonal to the heat exchange pipe, and the heat dissipation pipe is combined with the heat dissipation pipe. The width w in the ventilation direction of the portion of the heat dissipation fin where the heat exchange pipe is provided. ₁ and the heat exchanger, characterized in that the ratio w ₂ / w ₁ ventilation direction of the total width w ₂ of the heat radiation fins as 1.2 to 1.9. 2. A radiating fin is provided on its one surface with a restricting member that is in contact with the other surface of the adjacent radiating fin and restricts the distance between the adjacent fins. The heat exchanger described.