JP2000055509A - Heat exchanger for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger for an air conditioner capable of increasing the degree of supercooling of the refrigerant of a condenser without using a means for increasing the amount of charged refrigerant. SOLUTION: A heat exchanger is provided with an inner insert body 8 in a heat transfer pipe 7 in the outlet side of refrigerant as a condenser. The inner insert body 8 has a cylindrical inner insert main body 80 disposed coaxially with the heat transfer pipe 7 and a plurality of protruding parts 82. These protruding parts 82 extend axially with respect to the inner insert main body 80 and protruding radially to abut on the inner wall surface of the heat transfer pipe 7. A passage is narrowed toward the inner wall surface side of the heat transfer pipe 7 due to the inner insert main body 80 to increase the flow velocity of refrigerant and flow the refrigerant only in the inner wall surface side of the heat transfer pipe 7. Further, a heat transfer is achieved between the inner wall surface of the heat transfer pipe 7 and the refrigerant through the inner insert body 8. Accordingly, the heat transfer performance of the heat transfer pipe 7 in the outlet side in which the inner insert body 8 is provided is improved more than those of other parts of the heat transfer pipe 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indoor or outdoor heat exchanger of an air conditioner, and more particularly to an air conditioner having an improved structure inside a heat transfer tube so that a supercooling degree as a condenser can be increased. It relates to a heat exchanger.

[0002]

2. Description of the Related Art FIG. 14 is a schematic diagram showing a general configuration of heat exchangers 2 and 3 constituting a refrigeration cycle in an air conditioner. Here, as shown in FIG. 15, the refrigeration cycle of a general air conditioner has a compressor 1, an indoor heat exchanger 2, a throttle mechanism 4, an outdoor heat exchanger 3, and a four-way valve 5 connected by refrigerant pipes. The four-way valve 5 switches between a heating operation in which the refrigerant flow direction is as indicated by a solid arrow and a cooling operation in which the refrigerant flow direction is also indicated by a dashed arrow. In such an air conditioner, the indoor heat exchanger 2 serves as a condenser (radiation side) during the heating operation, and the outdoor heat exchanger 3 serves as the condenser during the cooling operation.

[0003] Generally, these heat exchangers 2 and 3 are shown in FIG.
As shown in FIG. 5, the heat transfer pipe 7 includes a bent heat transfer pipe 7 through which the refrigerant flows, and a number of fins 6 through which the heat transfer pipe 7 passes. The refrigerant flowing in the heat transfer tubes 7 of the heat exchangers 2 and 3 as condensers exchanges heat with a fluid such as air flowing outside the heat transfer tubes 7 in a process from the refrigerant inlet side to the outlet side to radiate heat, Condensed into liquid refrigerant.

Heat exchangers 2 and 3 as such condensers
As a means for improving the performance of the above, that is, for improving the degree of supercooling of the refrigerant at the refrigerant outlet side, it is generally considered to increase the amount of refrigerant charged into the refrigeration cycle.

Conventionally, a heat exchanger having a so-called multi-pass configuration (in this case, an indoor heat exchanger having a 2-1 pass configuration) 2 "as shown in FIG. 16 has also been proposed. In FIG. The indoor heat exchanger 2 ″ including the shape heat exchanger 20 and the flat heat exchanger 22 includes a heat transfer tube 7 having a two-pass configuration on the refrigerant inlet side as a condenser (as indicated by an arrow).
A one-pass configuration is formed from the junction 24 on the way to the exit side.

As means for improving the degree of supercooling of the refrigerant in the heat exchanger 2 ″ having such a multi-pass structure,
As shown in FIG. 16, a proposal has been made to increase the flow rate of the refrigerant by increasing the length of the heat transfer tube 7 in the one-pass portion on the outlet side, and to increase the amount of charged refrigerant.

[0007]

The above-mentioned conventional heat exchangers for air conditioners have the following problems. In other words, if the amount of refrigerant charged is increased, the reliability of the compressor is reduced. To prevent this, it is necessary to add auxiliary equipment such as an accumulator (gas-liquid separator) and a receiver (liquid receiver). There's a problem.

In a heat exchanger having a multi-pass structure as shown in FIG. 16, if the heat transfer tubes 7 in the small number of passages on the outlet side are made long, the heat transfer tubes 7 occupied by the liquid refrigerant having a low heat transfer coefficient can be obtained. And the heat transfer performance of the entire heat exchanger decreases,
The heat exchanger temperature will be high. Further, when the heat exchanger is an evaporator, there is also a problem that the pressure loss of the refrigerant in the heat transfer tube 7 in the small-pass portion on the inlet side is increased, and the evaporating capacity is reduced.

The present invention has been made in view of the above points, and increases the amount of refrigerant to be charged and increases the length of the heat transfer tube in the small number of outlets on the outlet side in a heat exchanger having a plurality of passes. It is an object of the present invention to provide a heat exchanger of an air conditioner that can obtain a large degree of supercooling of a refrigerant in a case where the heat exchanger is used as a condenser.

[0010]

A first means is that in a heat exchanger of an air conditioner provided with a heat transfer tube through which a refrigerant flows, the heat transfer at a refrigerant outlet side when the heat exchanger is a condenser. An insert is provided in the tube, and the insert is provided with a substantially cylindrical insert body disposed substantially coaxially in the heat transfer tube, and an inner wall surface of the heat transfer tube provided on the surface of the body. A heat exchanger for an air conditioner, comprising: a plurality of projections that come into contact with each other.

According to the first means, inside the heat transfer tube provided with the insert, the flow passage is narrowed by the insert body to the inner wall surface side of the heat transfer tube, and the flow rate of the refrigerant increases. In addition, since the refrigerant flows only on the inner wall surface side of the heat transfer tube, heat transfer between the inner wall surface of the heat transfer tube and the refrigerant can be promoted. Further, since the plurality of protrusions of the insert are in contact with the inner wall surface of the heat transfer tube, indirect heat transfer between the inner wall surface of the heat transfer tube and the refrigerant can be achieved through the insert. With these, the heat transfer performance inside the heat transfer tube provided with the insert can be improved as compared with other heat transfer tube portions. According to a second means, in the first means, the protrusion of the insert body extends spirally in the axial direction of the insert body body.

According to the second means, in the first means, the flow of the refrigerant is spirally swirled by the projections of the insert, so that the heat inside the heat transfer tube provided with the insert is provided. The transmission performance can be further improved.

A third means is the first means, wherein a plurality of grooves extending substantially in the axial direction are formed on the surface of the insert body.

According to the third means, in the first means, the heat transfer between the insert body and the refrigerant is promoted by the plurality of grooves of the insert body so that the heat can be transmitted through the insert body. The amount of indirect heat transfer between the inner wall surface of the heat transfer tube and the refrigerant can be increased, and the heat transfer performance inside the heat transfer tube provided with the insert can be further improved.

According to a fourth aspect, in any one of the first to third aspects, the insert is made of aluminum or an aluminum alloy.

According to the fourth means, in any one of the first to third means, by improving the thermal conductivity of the insert, the inner wall surface of the heat transfer tube through the insert, the refrigerant, And the amount of indirect heat transfer during the heat transfer can be increased, and the heat transfer performance inside the heat transfer tube provided with the insert can be further improved.

The fifth means is that in the heat exchanger of the air conditioner provided with the heat transfer tubes through which the refrigerant flows, a plurality of tube grooves extending substantially in the axial direction are formed on the inner wall surface of the heat transfer tubes. Is smaller on the refrigerant outlet side than on the refrigerant inlet side when the heat exchanger is a condenser.

According to the fifth means, the heat transfer between the inner wall surface of the heat transfer tube and the refrigerant can be promoted as the depth of the groove in the heat transfer tube becomes deeper. The heat transfer performance inside the heat transfer tube on the refrigerant outlet side in the case of a container can be improved as compared with the inlet side.

According to a sixth aspect, in any one of the first to fifth aspects, the heat exchanger is an indoor heat exchanger.

According to the sixth means, in any one of the first to fifth means, during the heating operation of the air conditioner in which the indoor heat exchanger serves as a condenser, excess refrigerant in the indoor heat exchanger is provided. By increasing the degree of cooling, the heating capacity of the air conditioner can be improved.

According to a seventh aspect, in any one of the first to fifth aspects, the heat exchanger is an outdoor heat exchanger.

According to the seventh means, in any one of the first to fifth means, during the cooling operation of the air conditioner in which the outdoor heat exchanger serves as a condenser, the excess amount of refrigerant in the outdoor heat exchanger. By increasing the degree of cooling, the cooling capacity of the air conditioner can be improved.

[0023]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 13 are views showing an embodiment of a heat exchanger of an air conditioner according to the present invention. In the embodiments of the present invention shown in FIGS. 1 to 13, the same components as those of the general heat exchanger of the air conditioner shown in FIGS. 14 and 15 or those of the conventional example shown in FIG. And description will be made with reference to FIGS. 14 and 15 as appropriate.

[First Embodiment] First, a first embodiment of the present invention will be described with reference to FIGS. First,
A refrigeration cycle of a general air conditioner shown in FIG. 15 includes a compressor 1, an indoor heat exchanger 2, a throttle mechanism 4, and an outdoor heat exchanger 3.
And the four-way valve 5 are connected by refrigerant pipes, respectively, so that the four-way valve 5 can switch between a heating operation in which the refrigerant flow direction is as indicated by a solid arrow and a cooling operation in which the refrigerant flow direction is also indicated by a dashed arrow. I have. In such an air conditioner, the indoor heat exchanger 2 is used during the heating operation.
However, during the cooling operation, the outdoor heat exchangers 3 each become a condenser (radiation side).

These heat exchangers 2 and 3 are generally connected to each other as shown in FIG.
As shown in FIG. 5, the heat transfer pipe 7 includes a bent heat transfer pipe 7 through which the refrigerant flows, and a number of fins 6 through which the heat transfer pipe 7 passes. The heat transfer tube 7 is generally a copper tube, and the fins 6 are generally an aluminum alloy plate. The refrigerant flowing in the heat transfer tubes 7 of the heat exchangers 2 and 3 as condensers exchanges heat with a fluid such as air flowing outside the heat transfer tubes 7 in a process from the refrigerant inlet side to the outlet side to radiate heat, Condensed into liquid refrigerant.

Here, as shown in FIG. 1, the heat exchangers 2, 3 of the present embodiment are inserted into the heat transfer tubes 7 on the refrigerant outlet side when the heat exchangers 2, 3 are condensers. A body 8 is provided. As shown in FIG. 2, the insert body 8 has a cylindrical insert body 80 coaxially arranged in the heat transfer tube 7 and a plurality (four in this case) provided on the surface of the body 80. And the projection 82. These projections 82 extend in the axial direction and protrude in the radial direction with respect to the insert body 80 (and the heat transfer tube 7), and the tips thereof are in contact with the inner wall surface of the heat transfer tube 7.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, inside the heat transfer tube 7 provided with the insert 8, the flow path is narrowed by the insert body 80 toward the inner wall surface side of the heat transfer tube 7, and the flow rate of the refrigerant is increased. Since the refrigerant flows only on the inner wall surface side of the heat transfer tube 7, heat transfer between the inner wall surface of the heat transfer tube 7 and the refrigerant can be promoted. Further, since the plurality of protrusions 82 of the insert 8 are in contact with the inner wall surface of the heat transfer tube 7, the indirect heat transfer between the inner wall surface of the heat transfer tube 7 and the refrigerant is performed through the insert 8. Can be planned. With these, the heat transfer performance inside the heat transfer tube 7 provided with the insert 8 can be improved as compared with the other heat transfer tube 7 portions.

Therefore, the heat transfer performance in the heat transfer tube 7 on the refrigerant outlet side when the heat exchangers 2 and 3 become condensers is improved.
The heat exchangers 2 and 3 can be used without increasing the amount of refrigerant charged.
It is possible to increase the degree of supercooling of the refrigerant at the time. For this reason, the compressor 1 accompanying the increase in the amount of refrigerant charged
It is possible to improve the performance of the condenser, improve the performance of the air conditioner, and reduce the size of the air conditioner, while avoiding a decrease in the reliability of the air conditioner and the need for auxiliary equipment.

Specifically, in FIG. 15, during the heating operation in which the indoor heat exchanger 2 becomes a condenser, the indoor heat exchanger 2
By increasing the degree of supercooling of the refrigerant in the above, the heating capacity of the air conditioner can be improved. On the other hand, during the cooling operation in which the outdoor heat exchanger 3 serves as a condenser, the cooling capacity of the air conditioner can be improved by increasing the degree of supercooling of the refrigerant in the outdoor heat exchanger 3.

Here, various modifications of the insert 8 of the present embodiment will be described with reference to FIGS. First, FIG.
In the insert body 8A shown in FIG.
It extends helically in the axial direction of 0. In this case, the flow of the refrigerant is spirally swirled by the projections 82 of the insert 8A, so that the heat transfer performance inside the heat transfer tube 7 provided with the insert 8A can be further improved.

Next, in the insert 8B shown in FIG. 4, a plurality of grooves 84 extending substantially in the axial direction are formed on the surface of the insert body 80. As shown in FIG. In this case, heat transfer between the insert body 80 and the refrigerant is promoted by the plurality of grooves 84 of the insert body 80, so that the heat transfer tube 7 through the insert body 8B is formed.
Increase the amount of indirect heat transfer between the inner wall surface and the refrigerant,
The heat transfer performance inside the heat transfer tube 7 provided with the insert 8B can be further improved.

Next, the insert body 8C shown in FIG. 5 has a plurality (four in this case) of plate-like contact portions 88 in close contact with the inner wall surface of the heat transfer tube 7 instead of the projections 82, and Contact part 88
And a connecting portion 86 for connecting the inner body 80 with the inner body 80. In this case, by increasing the contact area between the inner wall surface of the heat transfer tube 7 and the insert 8C by the plurality of plate-shaped contact portions 88, the gap between the refrigerant and the inner wall surface of the heat transfer tube 7 through the insert 8C is increased. The indirect heat transfer amount can be increased, and the heat transfer performance inside the heat transfer tube 7 provided with the insert 8C can be further improved.

It should be noted that the inserts 8 to 8C as described above are made of aluminum or an aluminum alloy having a high thermal conductivity, because the inner wall surface of the heat transfer tube 7 through the inserts 8 to 8C and the refrigerant From the viewpoint of increasing the amount of indirect heat transfer between the heat transfer pipe 7 and the heat transfer performance inside the heat transfer tube 7 provided with the insert 8.

[Second Embodiment] Next, FIGS.
The second embodiment of the present invention will be described with reference to FIG. In the present embodiment shown in FIGS. 6 to 9, the same components as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 6 shows an indoor heat exchanger 2 'of this embodiment.
FIG. 7 also shows an outdoor heat exchanger 3 '. These heat exchangers 2 'and 3' are so-called multi-pass heat exchangers. The indoor heat exchanger 2 'shown in FIG. 6 has a 2-1 pass structure and the outdoor heat exchanger 3' shown in FIG. Has a 4-2 path configuration.

Specifically, the indoor heat exchanger 2 'shown in FIG.
Has an arcuate heat exchanger 20 bent at the top, and a flat heat exchanger 22 disposed on a rear upper portion (right side portion in FIG. 6) of the arcuate heat exchanger 20. . The indoor heat exchanger 2 ′ includes a heat transfer tube 7 having a two-pass configuration on the refrigerant inlet side as a condenser (as indicated by an arrow). , And further passes through the flat heat exchanger 22 to the outlet side. In this case, among the heat transfer tubes 7 constituting the indoor heat exchanger 2 ′, the heat transfer tubes in the flat heat exchanger 22 are
Particularly, it is indicated by reference numeral 7a.

The outdoor heat exchanger 3 'shown in FIG.
The heat transfer tube 7 having a 2-pass × 2 = 4-pass configuration on the refrigerant inlet side as a condenser (as indicated by an arrow) has a 1-pass × 2 = 2-pass configuration from each merging portion 30 on the way. It leads to the exit side. In this case, among the heat transfer tubes 7 constituting the outdoor heat exchanger 3 ′, a total of four heat transfer tubes 7, two from the outlet side for each pass, are particularly indicated by reference numeral 7 b.

Next, the heat transfer tubes 7, 7a, 7b of each heat exchanger 2 ', 3' will be described with reference to FIGS. First, as shown in FIG. 8, among the heat transfer tubes 7, the insert 8D is provided only inside the heat transfer tubes 7a and 7b. These inserts 8D abut a cylindrical insert body 80 coaxially arranged in each of the heat transfer tubes 7a, 7b and an inner wall surface of the heat transfer tubes 7a, 7b provided on the surface of the body 80. And two pairs of projections 83.

Next, as shown in FIG. 9, the heat transfer tubes 7 (including the heat transfer tubes 7a and 7b) in each of the heat exchangers 2 'and 3'.
On the inner wall surface, a number of pipe grooves (ripple grooves) 70 extending in the axial direction are formed. And each heat exchanger 2 ',
Heat transfer tubes 7a, 7 on the refrigerant outlet side when 3 'is a condenser
The depth C of the inner groove 70 in b is deeper than the depth C of the inner groove 70 in the other heat transfer tubes 7.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, inside the heat transfer tubes 7a and 7b provided with the inserts 8D, the flow path is narrowed by the insert body 80 toward the inner wall surfaces of the heat transfer tubes 7a and 7b, and the flow rate of the refrigerant is reduced. And the refrigerant flows only on the inner wall surfaces of the heat transfer tubes 7a and 7b, so that heat transfer between the inner wall surfaces of the heat transfer tubes 7a and 7b and the refrigerant can be further promoted.

Further, as the depth C of the inner grooves 70 of the heat transfer tubes 7, 7a, 7b becomes larger, the heat transfer between the inner wall surfaces of the heat transfer tubes 7, 7a, 7b and the refrigerant is further promoted. The heat transfer between the inner wall surface and the refrigerant in the deeper heat transfer tubes 7 a and 7 b having a depth C of 70 can be improved as compared with the other heat transfer tubes 7.

Therefore, the heat transfer performance inside the heat transfer tubes 7a and 7b on the refrigerant outlet side when the heat exchangers 2 'and 3' are condensers can be improved as compared with the other heat transfer tubes 7. The heat exchanger 2 ′,
At 3 ', the heat transfer tube 7 of the small-pass portion on the outlet side (1 pass portion in the indoor heat exchanger 2', 2 pass portion in the outdoor heat exchanger 3 ') does not have to be lengthened, nor does the amount of refrigerant charged increase. Also, the degree of supercooling of the refrigerant in the heat exchangers 2 'and 3' can be increased.

For this reason, the supercooling degree can be increased without making the heat transfer tube 7 in the above-mentioned small path portion on the condenser outlet side particularly long, so that the heat transfer tube 7 occupied by the liquid refrigerant having a low heat transfer coefficient can be obtained. Can be prevented from increasing and the heat transfer performance of the entire heat exchanger is reduced, and the temperature of the heat exchanger can be kept low. Further, when the heat exchangers 2 'and 3' are evaporators, the pressure loss of the refrigerant in the heat transfer tube 7 in the small-pass portion on the inlet side is prevented from increasing, and a decrease in the evaporation capacity is avoided. can do.

In addition, the performance of the condenser is improved, and the performance and the size of the air conditioner are improved while avoiding the decrease in the reliability of the compressor and the necessity of auxiliary equipment due to the increase in the amount of the charged refrigerant. It becomes possible.

[0045]

FIG. 8 and FIG. 9 and FIGS.
3, an example of the second embodiment will be described. In this embodiment, the heat transfer tubes 7, 7a, 7 shown in FIG.
The outer diameter A, the thickness B, and the depth C of the groove in the pipe b, and the outer diameter D of the insert body 80 shown in FIG. 8 are set as shown in FIG.

In FIG. 10, "flat heat exchanger"
There is a flat heat exchanger 2 in the indoor heat exchanger 2 '.
2 and the “arc-shaped heat exchanger” represents the other heat-transfer tubes 7 that constitute the arc-shaped heat exchanger 20 in the indoor heat exchanger 2 ′. . Similarly, "two outdoor heat exchanger outlets" refers to the heat transfer tubes 7b constituting two heat transfer tubes on the outlet side of each path in the outdoor heat exchanger 3 '. "Heat exchanger" means the other heat transfer tubes 7 of the outdoor heat exchanger 3 '.
Is represented.

As a conventional example, the heat transfer tubes 7a, 7
b, the heat exchanger tubes 2 ′,
3 ′ (in this case, FIGS. 11 and 12
The indoor and outdoor heat exchangers were prepared so as to obtain the condenser outlet temperature d) shown in FIG. Then, with respect to the actual air conditioner, the heat exchanger temperature was compared between the conventional example and the present embodiment.

The results of the comparison are shown in FIGS. Here, FIG. 11 is a graph showing the change of the heat exchanger temperature (heat exchange temperature) from the condenser inlet to the outlet.
FIG. 12 is a Mollier chart showing the enthalpy-pressure change of the refrigerant in relation to the temperature change of FIG.
3 is a table showing the temperature at each stage of each heat exchanger as a condenser, corresponding to FIGS. 11 and 12.

As can be seen from FIGS. 11 to 13, the temperature of the intermediate portion of the heat exchanger between the inlet and the outlet of the condenser is the same as the temperature c (= 39 ° C./43° C.) in this embodiment. ,
The temperature is about 1 ° C. lower than the temperature b (= 40 ° C./44° C.) of the conventional example. From this, according to the present embodiment,
It has been proved that the length of the heat transfer tube in the small-pass portion required to obtain the same degree of supercooling (condenser outlet temperature d) as in the conventional example can be made shorter, and the temperature of the heat exchanger can be kept low.

[0050]

According to the present invention, by increasing the heat transfer performance in the heat transfer tube on the refrigerant outlet side when the heat exchanger is a condenser, it is possible to increase the amount of refrigerant enclosed or to increase the heat capacity of a plurality of passes. It is possible to increase the degree of supercooling of the refrigerant in the heat exchanger without having to take a long heat transfer tube having a small number of paths on the outlet side in the exchanger. For this reason,
It is possible to improve the performance of the condenser, improve the performance of the air conditioner, and reduce the size of the air conditioner, while avoiding the decrease in the reliability of the compressor and the need for auxiliary equipment due to the increase in the amount of refrigerant charged. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a first embodiment of a heat exchanger of an air conditioner according to the present invention.

FIG. 2 is a cross-sectional view of a heat transfer tube provided with an insert in the heat exchanger shown in FIG.

FIG. 3 is a perspective view showing a modification of the insert in the embodiment shown in FIG. 1;

FIG. 4 is a view showing another modified example of the insert in the embodiment shown in FIG. 1 corresponding to FIG. 2;

FIG. 5 is a view showing still another modified example of the insert body in the embodiment shown in FIG. 1 corresponding to FIG. 2;

FIG. 6 is a cross-sectional view showing an indoor heat exchanger in a second embodiment of the air conditioner heat exchanger according to the present invention.

FIG. 7 is a cross-sectional view illustrating an outdoor heat exchanger (arrangement of heat transfer tubes) in a second embodiment of the heat exchanger of the air conditioner according to the present invention.

8 is a view showing a heat transfer tube provided with an insert in the heat exchanger shown in FIGS. 6 and 7, wherein FIG. 8 (a) is a transverse sectional view and FIG. 8 (b) is a longitudinal sectional view.

FIGS. 9A and 9B are diagrams showing the internal grooves of the heat transfer tubes in the heat exchangers shown in FIGS. 6 and 7, wherein FIG. 9A is a cross-sectional view of the heat transfer tubes and FIG. 9B is a partially enlarged view of FIG.

FIG. 10 is a table showing dimensions of each part of a heat transfer tube and an insert in the embodiment of the heat exchanger shown in FIGS. 6 and 7;

FIG. 11 is a graph showing a change in heat exchanger temperature from the inlet to the outlet of the condenser in a comparison between the embodiment of the heat exchanger shown in FIGS. 6 and 7 and a conventional heat exchanger.

12 is a Mollier diagram showing a change in enthalpy-pressure of a refrigerant in a comparison between the embodiment of the heat exchanger shown in FIGS. 6 and 7 and a conventional heat exchanger in relation to the temperature change in FIG. 11; The graph shown.

FIG. 13 is a table corresponding to FIGS. 11 and 12 showing temperatures at respective stages in the embodiment of the heat exchanger shown in FIGS. 6 and 7;

FIG. 14 is a schematic view showing a structure of a heat exchanger of a general air conditioner.

FIG. 15 is a refrigeration cycle diagram of a general air conditioner.

FIG. 16 is a cross-sectional view showing an example of a conventional indoor heat exchanger having a multi-pass configuration.

[Explanation of symbols]

2,2 ', 2 "indoor heat exchanger 3,3' outdoor heat exchanger 6 fins 7 heat transfer tube 7a heat transfer tube on refrigerant outlet side as condenser in indoor heat exchanger 7b as heat exchanger in outdoor heat exchanger Refrigerant outlet side heat transfer tube 70 Pipe groove 8, 8A, 8B, 8C, 8D Insert body 80 Insert body 82, 83 Projection section 84 Groove section 88 Plate contact section

Claims (7)

[Claims] In a heat exchanger of an air conditioner provided with a heat transfer tube through which a refrigerant flows, an insert is provided in the heat transfer tube on the refrigerant outlet side when the heat exchanger is a condenser. The insert has a substantially cylindrical insert main body disposed substantially coaxially in the heat transfer tube, and a plurality of protrusions provided on the surface of the main body and in contact with the inner wall surface of the heat transfer tube. The air conditioner heat exchanger characterized by the above-mentioned. 2. The heat exchanger for an air conditioner according to claim 1, wherein the protrusion of the insert body extends helically in the axial direction of the insert body. 3. A heat exchanger for an air conditioner according to claim 1, wherein a plurality of grooves extending substantially in the axial direction are formed on the surface of said insert body. 4. An insert according to claim 1, wherein said insert is made of aluminum or an aluminum alloy.
The heat exchanger for an air conditioner according to any one of claims 1 to 3. 5. A heat exchanger for an air conditioner having a heat transfer tube through which a refrigerant flows, wherein a plurality of tube grooves extending substantially in the axial direction are formed on an inner wall surface of the heat transfer tube. The heat exchanger of an air conditioner, wherein the depth of the refrigerant outlet side when the heat exchanger is a condenser is deeper than the refrigerant inlet side. 6. The heat exchanger for an air conditioner according to claim 1, wherein the heat exchanger is an indoor heat exchanger. 7. The heat exchanger for an air conditioner according to claim 1, wherein the heat exchanger is an outdoor heat exchanger.