JP2000329486A - Finned heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a finned heat exchanger exhibiting high performance in both the condenser and the evaporator of a refrigeration cycle by suppressing increase of heat transfer area and pressure loss in the heating tube on the gas inlet side. SOLUTION: The finned heat exchanger comprises an auxiliary heat exchanger 11a and a main heat exchanger 11b juxtaposed from the gas inlet side to the gas outlet side. The row of heating tube group 13a on the gas inlet side is separated from a plurality of rows of heating tube group 13b on the gas outlet side. Step pitch P1 of the heating tube group on the gas inlet side is set smaller than the step pitch P2 of the heating tube group on the gas outlet side and the number of heating tubes in a row is set lower on the gas inlet side than on the gas outlet side. Since increase in the heat transfer area and the pressure loss is suppressed in the heating tube on the gas inlet side, a high performance auxiliary heat exchanger is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finned heat exchanger mainly used for air conditioners and the like.

[0002]

2. Description of the Related Art A first conventional example of a recent finned heat exchanger will be described with reference to FIGS. FIG.
Is a perspective view showing a basic configuration of a finned heat exchanger, and FIG. 9 is a side view thereof. As shown in FIGS. 8 and 9, the finned heat exchanger includes an auxiliary heat exchanger 101 a and a main heat exchanger 101.
b. The auxiliary heat exchanger 101a is composed of a group of fins 102a arranged side by side at a predetermined interval and a group of heat transfer tubes 103a penetrating the group of fins at substantially right angles and forming a row, and is arranged on the gas inflow side (a). I have. The main heat exchanger 101b includes a fin group 102b arranged side by side at a predetermined interval,
A group of heat transfer tubes 10 penetrating through the fin group at a substantially right angle to form a row
3b and is disposed on the gas outflow side (b). 1
Reference numeral 04 denotes an airflow, which flows through the fin group 102a and the fin group 102b in the direction of the arrow, and
heat exchange with the fluid flowing in the tube b. When this finned heat exchanger is mounted on an indoor unit of a separate type air conditioner, it is common to provide cut portions at several places of the fin group 102b and bend several places to mount. It is.

In the above configuration, when used as a condenser in a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tubes flows in a gaseous state from the arrow A side, and is branched by a branch portion 105 into the heat transfer tube group 103b. Through a gas-liquid two-phase state due to heat exchange with the air flow 104, merges again at the branch portion 106, and flows out to the arrow B side through the heat transfer tube group 103a. As described above, the finned heat exchanger mainly includes the auxiliary heat exchanger 101a in which the fluid flowing in the heat transfer tube group 103a is almost in a liquid state and the fluid flowing in the heat transfer tube group 103b in a gas phase state or a gas-liquid two-phase state. And a heat exchanger 101b.

Accordingly, the heat transfer tube group 103 as a refrigerant pipe
a, the number of flow paths is reduced as the flow path approaches the refrigerant outlet,
Further, the auxiliary heat exchanger 101a, which is arranged on the gas inflow side (a) on the windward side of the mainstream airflow 104 and is a low-temperature portion on the condenser outlet side, is separated from the main heat exchanger 101b to be on the leeward side. The heat conduction to the gas outflow side can be cut off, and the condensing performance can be improved by facilitating supercooling.

A second conventional example, Japanese Patent Laid-Open Publication No. Sho 57-12
FIG. 10 shows a representative drawing of JP-A-7732. FIG. 10 is a perspective view of the heat exchanger. Finned heat exchanger 101c
Is composed of heat transfer tube groups 103c and 103d, and a number of fins 102c mounted orthogonal to the heat transfer tube groups 103c and 103d.

When used as a condenser in a refrigeration cycle of an air conditioner, the finned heat exchanger 101c allows the high-temperature and high-pressure gas refrigerant to pass through the heat transfer tube group 103c and pass through the heat transfer tube group 1c.
It flows to the 03d side. Meanwhile, the heat transfer tube groups 103c, 10
The refrigerant flowing in 3d exchanges heat with the airflow indicated by arrow 104 and condenses. In this case, by providing the heat transfer tube group 103d of thin tubes on the gas inflow side (A) of the finned heat exchanger 101c, the flow velocity of the refrigerant flowing through the tubes in the liquid phase can be improved, and the performance is improved. It can be planned.

A third prior art, Japanese Patent Laid-Open Publication No.
FIG. 11 shows a representative drawing of the '389 publication. FIG. 11 is a side view of the finned heat exchanger, in which the row pitch P3 of the row of the heat transfer tube group 103f on the gas outflow side (b) of the heat exchanger 101e is shown.
Is made longer than the step pitch P4 of the row of the heat transfer tube group 103e on the gas inflow side (a).

With such a configuration, the ratio of the water stop area 108 of the heat transfer tube group 103f to the opening area of the finned heat exchanger 101e from which the gas 104 flows out can be reduced. Noise can be reduced.

A fourth conventional example, Japanese Patent Laid-Open Publication No.
FIGS. 12 and 13 show representative drawings of Japanese Patent No. 3386. FIG. 12 is a perspective view of an independent fin tube heat exchanger showing a part of a finned heat exchanger in detail, and FIG. 13 is a diagram showing an outdoor unit of a packaged air conditioner to which a fourth conventional example is applied.
The independent fin tube heat exchanger 101g is formed by the heat transfer tube 103g penetrating a plurality of independent fins 102g. Each independent fin 102g is configured to contact at its lower end 101i and its upper end 101h, and each end of the lower end 101i and the upper end 101h intersects at least one point when contacted. I do. Thereby, the drainage performance can be improved.

[0010]

However, in the configuration of the first conventional example, the temperature difference between the adjacent heat transfer tubes 103b in the two-phase region in the main heat exchanger 101b is within 0.5 degree. The temperature difference between adjacent heat transfer tubes 103a in the auxiliary heat exchanger 101a, which is a liquid phase region, is 0.5 degrees or more,
Heat loss due to heat conduction between adjacent heat transfer tubes in the auxiliary heat exchanger has a problem that cannot be ignored.

In the configuration of the second conventional example, the heat transfer tube group 1
If the thin tube is simply formed without changing the step pitch of 03d, the cause of the decrease in the fin efficiency is larger than the improvement of the heat transfer coefficient in the tube,
There was a problem that high performance could not be achieved.

Further, in the configuration of the third conventional example, the step pitch P3 of the row of the heat transfer tube group 103f on the gas outflow side (b) is made larger than the step pitch P4 of the row of the heat transfer tube group 103e on the gas inflow side (a). By increasing the length, the capacity of the heat exchanger on the gas outflow side is greatly reduced, and this reduced capacity must be compensated for by increasing the air volume, and as a result, does not contribute to the reduction of noise. When the step pitch P4 on the gas inlet side (a) is shortened while maintaining the step pitch P3 on the gas outlet side (b), the effect of noise reduction described in the third conventional example cannot be obtained, When acting as a vessel, the capacity on the air inflow side can be improved. But,
When operated as an evaporator, the number of heat transfer tubes increases, and the capacity decreases due to an increase in pressure loss. The third conventional example has such a problem.

In the structure of the fourth conventional example, as shown in FIG.
There are a number of cuts between 01i and the upper end 101h, which disrupt the airflow passing through the heat exchanger and the resistance of the airflow passing through the heat exchanger is significantly increased compared to a heat exchanger without cuts. Even if the ventilation resistance ratio is good, when the fin surface is operated as a condenser with a dry fin surface, the resistance that passes through the integrated fin without the lower end portion 101i or the upper end portion 101h increases, and the inside of the ventilation circuit When mounted on a vehicle, there is a problem that causes factors such as an increase in noise value and a decrease in air volume.

The present invention solves such a conventional problem and suppresses an increase in the area of the heat transfer tube on the gas inflow side and an increase in pressure loss in the tube, and is used for either a condenser or an evaporator of a refrigeration cycle. It is an object of the present invention to provide a finned heat exchanger that can exhibit high performance even when it is used.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a group of fins arranged in parallel at a predetermined interval, through which a gas flows, and a row of fins penetrating the fins at substantially right angles. And a step pitch between the heat transfer tubes in the heat transfer tube group on the gas inflow side is made smaller than a step pitch between the heat transfer tubes in the heat transfer tube group on the gas outflow side. ,
And the number of heat transfer tubes in one row of the heat transfer tube group on the gas inflow side is
The number of heat transfer tube groups on the gas outlet side is less than the number in one row, and the heat transfer area inside the tubes in the gas outlet side heat transfer tube group can be expanded, and the condensing capacity and evaporation ability can be improved. It is.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat exchanger with fins according to the first aspect of the present invention is arranged in parallel at predetermined intervals, and a fin group through which gas flows and a fin group formed at substantially right angles. A heat transfer tube group through which a fluid flows inside, and a step pitch between the heat transfer tubes of the heat transfer tube group on the gas inflow side,
The number of heat transfer tubes in one row of the heat transfer tube group on the gas inflow side should be made smaller than the step pitch between the heat transfer tubes of the heat transfer tube group on the gas outflow side. It is configured as follows.

According to the above configuration, the heat transfer area inside the tube of the heat transfer tube group on the gas inflow side is widened, and when used as a condenser, the supercooling in the liquid state is extremely low as the heat transfer performance in the tube is extremely low. The area can be increased, and an increase in pressure loss inside the pipe can be suppressed.

In the invention according to claim 2, the diameter of the heat transfer tube group on the gas inflow side is smaller than the diameter of the heat transfer tube group on the gas outflow side.

According to the above configuration, the ventilation resistance when the airflow passes through the heat exchanger on the gas inflow side is reduced, and the flow velocity of the fluid flowing in the pipe is increased.

According to a third aspect of the present invention, the heat transfer tubes of the heat transfer tube group on the gas inflow side are formed in an elliptical or flat shape.

According to the above configuration, the distance between the fluid flowing near the center of the heat transfer tube and the tube wall can be reduced.

According to a fourth aspect of the present invention, the length of the fin between the heat transfer tubes in the heat transfer tube group on the gas inflow side is longer than the step pitch between the heat transfer tubes, In the heat transfer tube group, the length of the fin between the heat transfer tubes and the step pitch between the heat transfer tubes are set to be substantially equal.

According to this configuration, the length of the fin portion can be increased while maintaining the step pitch, the heat conduction between the stages of the heat transfer tubes can be suppressed, and the heat conduction loss between the stages in the heat transfer tubes can be reduced. You.

According to a fifth aspect of the present invention, a cutting portion or a punching portion is provided between the heat transfer tubes in all the fins of the row of the heat transfer tubes on the gas inflow side, and the cutting portion or the punching portion is provided. The configuration is such that the portion is inclined with respect to the main flow direction of the air flow.

According to this configuration, the loss due to heat conduction between the stages of the heat transfer tubes can be reduced.

According to a sixth aspect of the present invention, the fins between the heat transfer tubes are provided with a plurality of cuts and projections or projections and depressions substantially perpendicular to the main flow direction of the air flow.

According to this configuration, high performance can be achieved by the boundary layer leading edge effect at the cut-and-raised front edge portion, the heat transfer area can be increased by the uneven shape, and the turbulence can be promoted.

The heat transfer area of the inner surface per unit length of the heat transfer tubes in the row on the gas inflow side is larger than the heat transfer area of the heat transfer tube inner surface on the gas outflow side. It was done.

According to this structure, the heat transfer area can be increased at the condenser outlet and the evaporator inlet as the gas inflow side. The expansion of the heat transfer area can easily lead to an increase in the pressure loss in the pipe.However, by using it at the condenser outlet and evaporator inlet, the heat transfer area in the pipe can be increased while suppressing the decrease in condensation temperature and the increase in evaporation temperature. Can be achieved.

[0030]

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

(First Embodiment) FIG. 1 is a side view showing a finned heat exchanger according to the first embodiment of the present invention. The finned heat exchanger includes an auxiliary heat exchanger 11a located on the gas inflow side (a) of the airflow indicated by the arrow 4 and a main heat exchanger 11b located on the gas outflow side (b). Auxiliary heat exchanger 11a
Is a group of fins 12a arranged side by side at a predetermined interval, and a group of heat transfer tubes 1 penetrating the fins at substantially right angles and arranged in a meandering manner.
3a. The main heat exchanger 11b includes a large number of fin groups 12b arranged side by side at predetermined intervals, and a group of heat transfer tubes 13b penetrating the fin groups at substantially right angles and arranged in a meandering manner. The auxiliary heat exchanger 11a has six rows of heat transfer tubes of the group of heat transfer tubes 13a in a cascade, and the number of heat transfer tubes in one row of the group of heat transfer tubes 13b of 12 rows of one row of the main heat exchanger 11b. It is as follows. That is, the auxiliary heat exchanger 11a
Represents the number of tube stages of the heat transfer tube group 13a in one row,
b, the number of tubes is smaller than the number of tubes of the heat transfer tube group 13b in one row.
b. The auxiliary heat exchanger 11a sets the step pitch P1, which is the length between the heat transfer tube center of the heat transfer tube group 13a and the center of the next heat transfer tube, to the heat transfer tube group 1 of the main heat exchanger 11b.
3b, it is shorter than the step pitch P2 between the heat transfer tubes. Fifteen
Is a branch portion on the inlet side of the heat transfer tube group 13b of the main heat exchanger 11b, and 16 is a branch portion on the outlet side similarly.

The air flow 4 flows through the fin group 12a and the fin group 12b in the direction of the arrow, and exchanges heat with the fluid flowing in the tubes of the heat transfer tube group 13a and the heat transfer tube group 13b. When the air conditioner is installed in an indoor unit of a separate type air conditioner, it is general that an auxiliary or main heat exchanger is provided with several cuts or cuts, and is folded and mounted.

In the above configuration, when used as a condenser in a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tube flows in a gaseous state from the heat transfer tube of the main heat exchanger 11b as shown by arrow A and branches. The heat is separated from the heat transfer tube group 13b by the section 15 above and below the heat transfer pipe group 13b. The heat is exchanged with the gas flow 4 to form a liquid state through a gas-liquid two-phase state. It flows into the heat transfer tubes of the heat tube group 13a and flows out as indicated by the arrow B.

When acting as an evaporator in a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tubes is a gas-liquid two-phase state in which a group of heat transfer tubes arranged in tandem with the auxiliary heat exchanger 11a as shown by arrow B. After flowing into the heat transfer tube 13a and further diverging up and down the heat transfer tube group 13b at the branching portion 16 of the main heat exchanger 11b and exchanging heat with the airflow 4, they are joined again at the branching portion 15 and arrow from the heat transfer tube. Outflow like A.

According to this configuration, since the step pitch P1 of the heat transfer tube group 13a of the auxiliary heat exchanger 11a is shorter than the step pitch P2 of the heat transfer tube group 13b of the main heat exchanger 11b, the heat transfer area in the heat transfer tube is reduced. It is possible to increase the size of the auxiliary heat exchanger, thereby improving the performance of the auxiliary heat exchanger. Therefore, when acting as a condenser, the heat transfer performance inside the heat transfer tube can be increased in the auxiliary heat exchanger 11a in a very low liquid-phase supercooling region, thereby improving the heat transfer performance inside the tube. A large two-phase state is taken in the main heat exchanger 11b, so that the heat exchange capacity can be increased and the performance of the finned heat exchanger can be improved. In addition, when acting as an evaporator, by setting the number of stages of heat transfer tubes in one row of the auxiliary heat exchanger 11a to be smaller than the number of stages in one row of the heat transfer tube group 13b of the main heat exchanger, the pressure in the tube is reduced. It is possible to suppress an increase in loss and improve the evaporation ability.

Embodiment 2 FIG. 2 is a side view showing a finned heat exchanger according to Embodiment 2 of the present invention. This finned heat exchanger is different from the first embodiment only in the configuration in which the tube diameter of the heat transfer tubes in the heat transfer tube group of the auxiliary heat exchanger is smaller than the tube diameter in the heat transfer tube group of the main heat exchanger. Parts having the same configuration and operation and effect other than those described above are denoted by reference numerals, detailed description thereof will be omitted, and different parts will be mainly described.

Reference numeral 21a is an auxiliary heat exchanger, and 21b is a main heat exchanger. The auxiliary heat exchanger 21a sets the outer diameter d of the heat transfer tubes in the heat transfer tube group 23a to the main heat exchanger 21b.
Is smaller than the outer diameter D of the heat transfer tubes in the heat transfer tube group 23b. P1 is a step pitch which is the length between the center of the heat transfer tube group of the heat transfer tube group 23a of the auxiliary heat exchanger 21a and the center of the next heat transfer tube group, and is shorter than the step pitch P2 of the heat transfer tube group 23b of the main heat exchanger 21b. It is composed. In the auxiliary heat exchanger 21a, the number of heat transfer tubes of the heat transfer tube group 23a is set to be equal to or less than the number of heat transfer tubes in one row of the heat transfer tube group 23b of the main heat exchanger 21b. 22a and 22b are auxiliary heat exchangers 21a
And the fin group of the main heat exchanger 21b, and 25 and 26 are branch portions of the heat transfer tube group 23b. An arrow 4 indicates the main flow direction of the air flow.

In the above configuration, when used as a condenser in a refrigeration cycle of an air conditioner, the fluid flowing through the heat transfer tube is in a gaseous state as shown by arrow A in the main heat exchanger 21b as in the first embodiment. The heat flows into the heat pipe and is divided into upper and lower portions of the heat transfer tube group 23b from the branch portion 25. The heat exchange with the gas flow 4 causes a liquid-phase state through a gas-liquid two-phase state. Flows into the heat transfer tubes of the heat transfer tube group 23a in a vertical line and flows out as indicated by the arrow B.

When acting as an evaporator in a refrigeration cycle of an air conditioner, the fluid flowing through the heat transfer tubes is in a gas-liquid two-phase state, and is a group of heat transfer tubes arranged in tandem with the auxiliary heat exchanger 21a as shown by arrow B. After flowing into the heat transfer tube 23a, the heat is further divided at the branching portion 26 of the heat transfer tube of the main heat exchanger 21b up and down the heat transfer tube group 23b to exchange heat with the airflow 4, and then merged again at the branching portion 25. It flows out as shown by arrow A from the heat transfer tube.

According to this configuration, the step pitch P1 of the heat transfer tube group 23a of the auxiliary heat exchanger 21a is shorter than the step pitch P2 of the heat transfer tube group 23b of the main heat exchanger 21b, and the transfer pitch of the auxiliary heat exchanger 21a is further reduced. Heat transfer tube outer diameter d in heat tube group 23a
Is smaller than the outer diameter D of the heat transfer tubes in the heat transfer tube group 23b of the main heat exchanger 21b, so that the reduction in the fin efficiency due to the narrowing of the tubes is suppressed, and the heat transfer area in the heat transfer tubes is increased. The performance of the auxiliary heat exchanger 21a can be improved by improving the heat transfer performance by increasing the flow velocity of the fluid flowing through the heat pipe. Therefore, when acting as a condenser, a large amount of supercooling region in a liquid state, which is very low in the pipe heat transfer performance, can be taken in the auxiliary heat exchanger 21a. Many states can be taken in the main heat exchanger 21b, the heat exchange capacity can be increased, and the performance of the finned heat exchanger can be improved. When acting as an evaporator, the number of stages of heat transfer tubes in one row of the auxiliary heat exchanger 21a is one of that of the main heat exchanger 21b.
By making the number of stages smaller than the number of heat transfer tubes in the row,
It is possible to suppress an increase in pressure loss in the pipe and to improve the evaporation capacity.

(Embodiment 3) FIG. 3 is a sectional view showing an auxiliary heat exchanger part in a finned heat exchanger according to an embodiment 3 of the present invention. This finned heat exchanger is different from the first embodiment only in the configuration in which the heat transfer tubes in the heat transfer tube group of the auxiliary heat exchanger are formed in a flat shape. , Detailed description is omitted, and different portions will be mainly described.

Reference numeral 31a is an auxiliary heat exchanger. In the auxiliary heat exchanger 31a, the heat transfer tubes in the heat transfer tube group 33a have a flat shape. 32a is an auxiliary heat exchanger 31a
The fins. Numeral 4 indicates the main flow direction.

According to the above configuration, when used as a condenser or an evaporator in a refrigeration cycle of an air conditioner, the fluid flows through the heat transfer tube and exchanges heat with the airflow 4 as in the first embodiment.
The fluid near the center flowing in the heat transfer tube exchanges heat with the inner wall of the heat transfer tube by heat conduction and convection in the fluid, particularly in the liquid phase region of the condenser, and passes through the heat exchanger through fins outside the heat transfer tube. Exchange heat with airflow. By making the heat transfer tubes of the heat transfer tube group 33a of the auxiliary heat exchanger 31a have a flat shape, the fluid near the center of the fluid flowing in the tube can shorten the distance from the tube inner wall,
The amount of heat exchange by heat conduction can be increased. Further, by adopting the flat shape, the hydraulic diameter becomes small, the Reynolds number becomes large, and the turbulence is promoted, so that the performance of the auxiliary heat exchanger can be further improved.

When acting as an evaporator, the number of heat transfer tubes in one row of the auxiliary heat exchanger 31a is set to be smaller than the number of stages in one row of the main heat exchanger. Can be suppressed and the evaporation ability can be improved.

The same effect can be obtained by using an elliptical shape instead of the flat shape of the heat transfer tubes of the heat transfer tube group 33a of the third embodiment.

(Embodiment 4) FIG. 4 (a) is a perspective view showing a finned heat exchanger according to the invention of Embodiment 4, and FIG.
Is a front view. In the heat exchanger with fins, the length of the fin between the heat transfer tubes of the heat transfer tube group on the gas inflow side is longer than the step pitch between the heat transfer tubes, and the heat transfer tubes of the heat transfer tube group on the gas outflow side. The only difference from the first embodiment is that the length of the fins between the heat transfer tubes and the step pitch between the heat transfer tubes are substantially the same. The detailed description will be omitted, and different portions will be mainly described.

Reference numeral 41a is an auxiliary heat exchanger, and 41b is a main heat exchanger. 42a and 42b are auxiliary heat exchangers 4 respectively.
1a and a fin group of the main heat exchanger 41b. The fin group 42a of the auxiliary heat exchanger 41a is formed in a corrugated shape. 43a and 43b are auxiliary heat exchangers 41a, respectively.
And the heat transfer tube group of the main heat exchanger 41b. Also, P1 and P
2 is a step pitch of the length between the center of the heat transfer tube of the heat transfer tube group 43a of the auxiliary heat exchanger 41a and the center of the heat transfer tube of the heat transfer tube group 43b of the main heat exchanger 41b. d is the heat transfer tube outer diameter of the heat transfer tube group 42a of the auxiliary heat exchanger 41a, and D is the heat transfer tube outer diameter of the heat transfer tube group 42b of the main heat exchanger 41b. The auxiliary heat exchanger 41a on the gas inflow side (a) has the length L1 + L2 + L3 + L4 of the corrugated fin between the heat transfer tubes of the heat transfer tube group 42a longer than the step pitch P1 between the heat transfer tubes. The main heat exchanger 41b on the gas outflow side (b) is configured such that the length of the fin between the heat transfer tubes of the heat transfer tube group 43b and the step pitch P2 between the heat transfer tubes are substantially equal. Things.

According to the above configuration, when used as a condenser in a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tubes flows in from the main heat exchanger 41b side and becomes the auxiliary heat exchanger 41a as in the first embodiment. Spill to the side. Also, when used as an evaporator, as in the first embodiment, it flows in from the auxiliary heat exchanger 41a side and flows out to the main heat exchanger 41b side. And when acting as a condenser, the heat transfer tube group 4 of the main heat exchanger 41b
3b is in a two-phase state in a saturation region,
The temperature difference between the stages 3b is about 0.2 to 0.3 degrees, and there is almost no temperature difference. On the other hand, the fluid in the heat transfer tube group 43a of the auxiliary heat exchanger 41a is in a liquid phase state, and the temperature difference between the heat transfer tubes between the stages of the heat transfer tube group 43a is large.

According to the invention of the fourth embodiment, however, the heat conduction loss due to the temperature difference between the heat transfer tubes of the heat transfer tube group 43a of the auxiliary heat exchanger 41a is reduced by the fin length L1 + L between the heat transfer tubes.
Since 2 + L3 + L4 is longer than the step pitch P1 between the heat transfer tubes, the heat transfer loss in the auxiliary heat exchanger 41a is reduced, and the heat transfer tubes in the main heat exchanger 41b having a small heat transfer loss due to the temperature difference between the stages. The configuration in which the fin length between the heat transfer tubes of the group 43b and the step pitch P2 of the heat transfer tubes are maintained substantially equal to maintain the fin efficiency can improve the performance of the finned heat exchanger.

When acting as an evaporator, the number of heat transfer tube groups in one row of the auxiliary heat exchanger 41a is smaller than the number of heat transfer tube groups in one row of the main heat exchanger 41b. By doing so, it is possible to suppress an increase in pressure loss in the pipe and improve the evaporation capacity.

Note that the effects of the heat transfer tube group of the auxiliary heat exchanger 41a, such as thinning and flat shape of the heat transfer tube, are described in the first embodiment.
Further, the same effects as those of Nos. 1 to 3 are further obtained.

(Embodiment 5) FIG. 5 is a sectional view of an auxiliary heat exchanger in a finned heat exchanger according to a fifth embodiment of the present invention. This finned heat exchanger differs from the first embodiment in that the fins between the heat transfer tubes of the heat transfer tube group on the gas inflow side are provided with a cut portion or a punched portion that is inclined with respect to the gas flow direction. Therefore, other parts having the same configuration and operation and effect are denoted by reference numerals, detailed description thereof will be omitted, and different parts will be mainly described.

Reference numeral 51a denotes an auxiliary heat exchanger comprising a group of fins 52a arranged side by side at intervals and a group of heat transfer tubes 53a penetrating the fin group 52a at right angles and arranged in a meandering manner. 57
Is a straight cut portion (also referred to as a cut portion) provided on the fin between the heat transfer tubes of the heat transfer tube group 53a with respect to the airflow direction indicated by the arrow 4. θ is the cut 5
7 is an angle of inclination between the mainstream direction of the airflow 4 and the airflow 4.

According to the above configuration, when used as a condenser in a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tube flows in from the main heat exchanger side and is turned on in the auxiliary heat exchanger 51a side as in the first embodiment. Leaks to Also, when used as an evaporator, as in the first embodiment, it flows in from the auxiliary heat exchanger 51a side and flows out to the main heat exchanger side. When operating as a condenser, the fluid in the heat transfer tubes of the main heat exchanger is in a two-phase state in a saturation region, and the temperature difference between the tube stages of the heat transfer tubes is 0.
There is almost no temperature difference at about 2 to 0.3 degrees. On the other hand, the fluid in the heat transfer tube group 53a of the auxiliary heat exchanger 51a is in a liquid phase, and the temperature difference between the heat transfer tubes and the tube stages of the heat transfer tubes is large.

However, in the invention of the fifth embodiment, the heat conduction loss caused by the temperature difference between the heat transfer tubes in the auxiliary heat exchanger 51a is reduced by the arrow 4 provided on the fin between the heat transfer tubes.
Linear cut 5 inclined with respect to the airflow direction indicated by.
7, the performance of the finned heat exchanger can be improved.

When acting as an evaporator, the number of heat transfer tubes in one row of the auxiliary heat exchanger 51a is set to be smaller than the number of pipes in one row of the main heat exchanger. By suppressing the increase in loss and improving the evaporation ability, the cut portion 57 is provided with the inclination angle θ with respect to the main flow direction of the air flow, so that the condensed water attached to the fin surface is not retained by the cut end surfaces 58a and 58b. It can be discharged and the increase in ventilation resistance when wet can be suppressed.

In the fifth embodiment, the cut portion 57 is a straight line. However, the same effect can be obtained even if the cut portion 57 has a curved or saw-like shape. Further, the same effect can be obtained not only in the cutout portion but also in a thin cutout portion (also referred to as a punched portion). In addition, the cut portion 57 of the fifth embodiment has an end surface 58.
Although a and 58b extend to the side of the heat transfer tubes of the heat transfer tube group 53a, they may be terminated before the heat transfer tubes of the heat transfer tube group 53a.

(Embodiment 6) FIG. 6 is a cross-sectional view of an auxiliary heat exchanger in a finned heat exchanger according to Embodiment 6 of the present invention. This finned heat exchanger is different from the above-described embodiment in that a plurality of cut-and-raised portions or irregularities are provided in a fin between the heat transfer tubes of the heat transfer tube group of the auxiliary heat exchanger in a direction substantially perpendicular to the main flow direction of the air flow. Since it is only different from 1, the other parts having the same configuration and operation and effect are denoted by reference numerals, detailed description thereof will be omitted, and different parts will be mainly described.

Reference numeral 61a denotes an auxiliary heat exchanger which is composed of a group of fins 62a arranged side by side at intervals and a group of heat transfer tubes 63a penetrating the fin group 62a at right angles and arranged in a meandering manner. 69
A plurality of cut-and-raised portions are provided on the fin between the heat transfer tubes of the heat transfer tube group 63a of the auxiliary heat exchanger 61a at a substantially right angle to the main flow direction of the air flow indicated by the arrow 4.

According to the above configuration, when used as a condenser of a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tube flows in from the main heat exchanger side and is turned on in the auxiliary heat exchanger 61a side as in the first embodiment. Leaks to Also, when used as an evaporator, as in the first embodiment, it flows in from the auxiliary heat exchanger 61a side and flows out to the main heat exchanger side. And the auxiliary heat exchanger 6
The heat transfer coefficient on the air side is promoted by the boundary layer leading edge effect due to the cut-and-raised fins 69 between the heat transfer tubes of the heat transfer tube group 63a of 1a, and is used in combination with the above-described configurations of the first to fifth embodiments. By doing so, each effect is further promoted.

In the sixth embodiment, the cut-and-raised portion 69 is a straight line. However, the same effect can be obtained even if the cut-and-raised portion 69 is curved or saw-toothed. In addition, if the shape is not concave but concave and convex, heat transfer can be promoted although the action is inferior to the cut and raised shape.

(Embodiment 7) FIG. 7 (a) is an enlarged sectional view of a heat transfer tube of an auxiliary heat exchanger in a finned heat exchanger according to the invention of Embodiment 7, and FIG. 7 (b) is a main heat exchanger. It is an expanded sectional view of a heat transfer tube. This heat exchanger with fins calculates the heat transfer area on the inner surface of the heat transfer tubes of the auxiliary heat exchanger per unit length as the heat transfer area of the heat transfer tubes on the inner surface of the heat transfer tube group of the main heat exchanger. Since the difference is only in the point of enlargement from the first embodiment, other parts having the same configuration and operation and effect are denoted by reference numerals, detailed description thereof will be omitted, and different parts will be mainly described.

Reference numeral 70a denotes an inner peripheral surface of a number of grooves formed on the inner surface of the heat transfer tubes constituting the heat transfer tube group 73a of the auxiliary heat exchanger, and has a peak height of h1. The groove inner peripheral surface 70a allows the heat transfer area of the tube inner surface per unit length of the heat transfer tube to be lower than the peak height h1 on the inner surface of the heat transfer tube forming the heat transfer tube group 73b of the main heat exchanger. The heat transfer area is set to be larger than the heat transfer area of the inner surface of the heat transfer tube in which the plurality of groove inner peripheral surfaces 70b having the peak height h2 are formed.

According to the above configuration, when used as a condenser in a refrigeration cycle of an air conditioner, the fluid flowing in the heat transfer tubes flows in from the main heat exchanger using the heat transfer tube group 73b as in the first embodiment. Flows out to the auxiliary heat exchanger side using the heat transfer tube group 73a. Also, when used as an evaporator, as in the first embodiment, it flows in from the auxiliary heat exchanger using the heat transfer tube 73a and flows out to the main heat exchanger using the heat transfer tube 73b. The heat transfer tube group 73a has a peak height h of the groove inner peripheral surface 70a.
1 is higher than the peak height h2 of the groove inner peripheral surface 70b of the heat transfer tube group 73b, so that the groove inner peripheral surface 70b of the heat transfer tube group 73b
By increasing the length, the heat transfer area on the inner surface of the heat transfer tube is increased, and the performance of the auxiliary heat exchanger can be improved. On the other hand, by increasing the peak height of the groove inner peripheral surface 70a of the heat transfer tube group 73a, there is a concern that the pressure loss in the tube may increase, but the inside of the auxiliary heat exchanger is in a liquid phase state, the density is large, and the flow rate is large. Can be said to be almost unaffected by the pressure loss.

When the evaporator is used as an evaporator, the increase in pressure loss in the tube is only a part of the inlet side by using the heat transfer tube group 73a of the auxiliary heat exchanger at the evaporator inlet side, and the evaporating temperature rise is reduced. Thus, the improvement of the heat transfer performance due to the increase in the mountain height h1 can be utilized, and the improvement of the evaporation ability can be achieved.

Further, the invention of the embodiment 7 is applied to the embodiments 1 to
2. By combining with the inventions of the fourth to sixth embodiments, it is possible to further improve the performance of the finned heat exchanger.

[0067]

As is apparent from the above embodiment, the invention according to claim 1 of the present invention is arranged in parallel at a predetermined interval, and a fin group through which gas flows, and the fin group are formed at substantially right angles. And a heat transfer tube group through which a fluid flows, and a step pitch between the heat transfer tubes of the gas inlet side heat transfer tube group is provided between the heat transfer tubes of the gas outlet side heat transfer tube group. The number of heat transfer tubes in one row of the heat transfer tube group on the gas inflow side is made smaller than the number of heat transfer tubes in one row of the heat transfer tube group on the gas outflow side. The heat area can be improved, and by limiting the number of heat transfer tubes, the condensing capacity and the evaporating capacity can be improved.

Further, according to the second aspect of the present invention, the diameter of the heat transfer tube group on the gas inflow side is made smaller than the diameter of the heat transfer tube group on the gas outflow side. The ventilation resistance at the time of passage can be reduced, the flow velocity of the fluid flowing in the heat transfer tube can be improved, and the heat transfer coefficient can be improved.

According to a third aspect of the present invention, the heat transfer tubes of the heat transfer tube group on the gas inflow side are formed in an elliptical or flat shape. , The distance between them can be reduced, and the heat transfer coefficient can be improved to achieve higher performance.

Further, according to the invention, the length of the fin between the heat transfer tubes of the heat transfer tube group on the gas inflow side is longer than the step pitch between the heat transfer tubes, and the heat transfer tube on the gas outflow side is provided. The length of the fins between the heat transfer tubes in the group and the step pitch between the heat transfer tubes are configured to be approximately the same length.The length of the fin portion can be increased while maintaining the step pitch. Heat conduction can be suppressed, and high performance can be achieved by reducing heat conduction loss between the heat transfer tubes.

The invention according to claim 5 is characterized in that the fins between the heat transfer tubes of the heat transfer tube group on the gas inflow side include:
A cutting portion or a punching portion having a predetermined length is provided, and the cutting portion or the punching portion is inclined with respect to the main flow direction of the air flow, so that loss due to heat conduction between the heat transfer tubes and the heat transfer tubes can be reduced, and high performance can be achieved. Can be achieved.

According to a sixth aspect of the present invention, the fin between the heat transfer tubes is provided with a plurality of cuts or projections substantially perpendicular to the main flow direction of the air flow. High performance can be achieved by improving the performance by the boundary layer leading edge effect in the portion, expanding the heat transfer area by the uneven shape, and promoting turbulence.

Further, according to the present invention, the heat transfer area of the heat transfer tube group per unit length of the heat transfer tube group on the gas inflow side is reduced by the heat transfer tube inner surface of the heat transfer tube group on the gas outflow side. The heat transfer area is larger than the heat transfer area. For example, the heat transfer area is increased at the condenser outlet and the evaporator inlet, which are used in the refrigeration cycle and on the gas inflow side, so that higher performance can be achieved. On the other hand, the expansion of the heat transfer area on the inner surface of the heat transfer tube tends to increase the pressure loss in the tube, but by using it at the condenser outlet and evaporator inlet, it is possible to suppress the decrease in condensation temperature and the increase in evaporation temperature while suppressing the rise in evaporation temperature. Higher performance can be achieved by increasing the heat transfer area.

[Brief description of the drawings]

FIG. 1 is a side view of a finned heat exchanger according to a first embodiment of the present invention.

FIG. 2 is a side view of the finned heat exchanger according to the second embodiment.

FIG. 3 is a sectional view of an auxiliary heat exchanger in the finned heat exchanger according to the third embodiment.

FIG. 4A is a perspective view of a main part of a heat exchanger with fins showing a fourth embodiment; FIG. 4B is a front view of a main part of an auxiliary heat exchanger showing the fourth embodiment;

FIG. 5 is a sectional view of an auxiliary heat exchanger in the finned heat exchanger according to the fifth embodiment.

FIG. 6 is a sectional view of an auxiliary heat exchanger in the finned heat exchanger according to the sixth embodiment.

7A is a cross-sectional view of a heat transfer tube of an auxiliary heat exchanger in a finned heat exchanger according to the seventh embodiment. FIG. 7B is a main heat exchanger in a finned heat exchanger according to the seventh embodiment. Cross section of heat transfer tube

FIG. 8 is a perspective view of a finned heat exchanger showing a first conventional example.

FIG. 9 is a side view of the finned heat exchanger.

FIG. 10 is a perspective view of a finned heat exchanger showing a second conventional example.

FIG. 11 is a side view of a finned heat exchanger showing a third conventional example.

FIG. 12 is a perspective view of a heat exchanger with independent fins showing a fourth conventional example.

FIG. 13 is a top view of an outdoor unit of an air conditioner equipped with a heat exchanger with independent fins showing a fourth conventional example.

[Explanation of symbols]

4 Main flow direction of air flow (a) Gas inflow side (b) Gas outflow side 11a, 21a, 31a, 41a, 51a, 61a Auxiliary heat exchangers 11b, 21b, 41b Main heat exchangers 13a, 23a, 33a, 43a, 53a, 63a, 7
3a Heat transfer tube group of auxiliary heat exchanger 13b, 23b, 43b, 73b Heat transfer tube group of main heat exchanger 12a, 22a, 32a, 42a, 52a, 62a Fin group of auxiliary heat exchanger 13b, 23b, 32b, 42b Main Fin group of heat exchanger 57 Notch 69 Cutting and raising of fin surface between heat transfer tubes 70a Inner surface of groove of heat transfer tube of auxiliary heat exchanger 70b Inner surface of groove of heat transfer tube of main heat exchanger d Auxiliary heat exchanger Heat transfer tube outer diameter D Heat transfer tube outer diameter of main heat exchanger L1, L2, L3, L4 Fin length between heat transfer tubes P1 Step pitch of heat transfer tubes of auxiliary heat exchanger P2 Step of heat transfer tubes of main heat exchanger Pitch θ Main stream direction of air flow and inclination angle of cut

Claims (7)

[Claims] 1. A group of fins, which are arranged in parallel at a predetermined interval and through which gas flows, and a group of heat transfer tubes through which the fins penetrate at substantially right angles to form a row and through which a fluid flows. Prepared,
The step pitch between the heat transfer tubes in the heat transfer tube group on the gas inflow side is made smaller than the step pitch between the heat transfer tubes in the heat transfer tube group on the gas outflow side, and the heat transfer tubes in one row of the heat transfer tube group on the gas inflow side are reduced. A finned heat exchanger in which the number is less than or equal to the number in one row of the heat transfer tube group on the gas outflow side. 2. The finned heat exchanger according to claim 1, wherein the diameter of the heat transfer tube group on the gas inflow side is smaller than the diameter of the heat transfer tube group on the gas outflow side. 3. The finned heat exchanger according to claim 1, wherein the heat transfer tubes of the heat transfer tube group on the gas inflow side are formed in an elliptical or flat shape. 4. The length of the fin between the heat transfer tubes of the heat transfer tube group on the gas inlet side is longer than the step pitch between the heat transfer tubes, and the length of the fin between the heat transfer tubes of the heat transfer tube group on the gas outlet side. The finned heat exchanger according to any one of claims 1 to 3, wherein the length of the fins and the step pitch between the heat transfer tubes are substantially equal. 5. A fin between a heat transfer tube and a heat transfer tube of a heat transfer tube group on the gas inflow side is provided with a cut portion or a punched portion having a predetermined length, and the cut portion or the punched portion is provided with respect to a main flow direction of an air flow. The finned heat exchanger according to any one of claims 1 to 4, which is inclined. 6. A fin between a heat transfer tube and a heat transfer tube,
The finned heat exchanger according to any one of claims 1 to 5, wherein a plurality of cut-and-raised portions or irregularities are provided substantially at right angles to the main stream direction of the air flow. 7. The heat transfer area of the inner surface of the heat transfer tube group per unit length of the heat transfer tube group on the gas inflow side is larger than the heat transfer area of the heat transfer tube inner surface of the heat transfer tube group on the gas outflow side. 1 to
The finned heat exchanger according to claim 2 or any one of claims 5 to 6.