JPH11159984A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a forced convection type heat exchanger for refrigeration/air conditioning in which high heat exchanging performance can be kept even it the refrigerant tube is made oval, flattened or reduced in diameter in order to reduce the quantity of the refrigerant. SOLUTION: A plurality of straight parts of refrigerant tubes 3A arranged substantially orthogonally to the air flow 4 are integrated with a large number of fins 2A juxtaposed at an interval in the axial direction of the straight parts of refrigerant tubes 3A such that the major part is substantially orthogonal to the straight parts of refrigerant tubes 3A thus constituting a heat exchanger. The straight parts of refrigerant tubes 3A has oval or flat cross-section and the long axis thereof is substantially orthogonal to the air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a heat exchanger,
In particular, it relates to a forced convection type heat exchanger for refrigeration and air conditioning that can maintain a high heat exchange performance even if the refrigerant pipe is made elliptical, flat, or narrow in diameter to reduce the amount of refrigerant. is there.

[0002]

2. Description of the Related Art As a forced convection type heat exchanger used for refrigeration and air-conditioning equipment such as a refrigerator and an air conditioner, a refrigerant pipe as a heat transfer pipe through which a refrigerant flows and a relatively dense pipe through which air flows are provided. A cross fin tube type having a main structure portion in which substantially flat fins arranged at intervals (fin pitches) are fixed and integrated so as to be substantially orthogonal to each other and are integrated is the most common and occupies most. This cross fin tube type heat exchanger uses a single-phase heat transfer of air as compared with the refrigerant side which performs boiling / condensation heat transfer or liquid single-phase heat transfer, so that the heat transfer coefficient of the air side is low due to the fins. There is a characteristic that the heat transfer area can be compensated for by increasing the heat transfer area, and the heat exchange performance can be improved as a whole.

[0003] Generally, a refrigerant pipe comprises a plurality of straight pipes arranged at regular intervals and arrangement and a connecting pipe which connects or merges / branches both ends thereof in order. Fixed to the tube. Due to differences in installation space, blower specifications, and other conditions, home refrigerators are mainly based on the number of straight pipe sections (the number of steps) in the step direction, which is the direction perpendicular to the airflow and the pipe axis of the straight pipe sections. There is a large number of straight pipe sections (the number of rows) in the row direction, which is also the ventilation direction, and a heat exchanger having an overall shape with a small front area but a large depth when viewed from the upstream side in the ventilation direction is used. Further, in the air conditioner, a heat exchanger having an overall shape in which the number of stages of the straight pipe portion of the refrigerant pipe is greater than the number of rows, the front surface area is large, and the depth is small.

[0004] A general heat exchanger for refrigeration and air conditioning will be described with reference to FIGS. 13 is a perspective view showing a general heat exchanger for a refrigerator, particularly an evaporator, FIG. 14 is a side sectional view of FIG. 13, and FIG. 15 is a general heat exchanger for an air conditioner. FIG. 16 is a side sectional view of FIG. In each of these drawings, the same reference numerals are used for the same functional parts in both the refrigerator and the air conditioner.

[0005] The heat exchanger 1 shown in each figure comprises a fin 2 and a refrigerant pipe 3, and has a function of efficiently exchanging heat between an air flow 4 indicated by a thick arrow and a refrigerant flowing inside the refrigerant pipe 3. Having. Heat exchanger 1 for both refrigerator and air conditioner
Is a refrigerant pipe 3 arranged substantially orthogonal to the air flow 4.
A plurality of straight pipes (a central part in the width direction of the heat exchanger) and a main part of the straight pipe of the refrigerant pipe 3 are substantially orthogonal to each other;
It has a main structure portion in which the fins 2 arranged at intervals in the tube axis direction (which is also the width direction of the heat exchanger) are fixed and integrated, and at both ends in the width direction of the main structure portion. Is provided with a connecting pipe portion (not shown for merging / branching) for connecting the straight pipe portions of the refrigerant pipe 3 in order.

Among the heat exchangers for refrigerators shown in FIGS. 13 and 14, especially in the case of an evaporator, the air flow 4 and the refrigerant pipe 3 go in a step direction B which is a direction orthogonal to the pipe axis of the straight pipe section. Refers to reducing the number of straight pipe sections to two or three, increasing the number of straight pipe sections to seven to nine in the column direction A, which is the direction along the air flow 4, and making the fin pitch relatively coarse. Adopting a structure, good heat exchange can be performed even with a small installation space and a small air volume blower.

On the other hand, in the case of the heat exchanger for an air conditioner shown in FIGS. 15 and 16, the number of rows is reduced to 2 to 3 while the number of stages is increased to, for example, 10 or more, and the fin pitch is reduced. Is relatively dense, and a good heat exchange is performed by a blower having a large air volume by utilizing an installation method capable of increasing a front surface area. The heat exchanger 1 uses the fins 2 to increase the surface area effective for heat exchange by 10% of the outer surface area of the refrigerant pipe 3.
As the refrigerant pipe 3 expands to 20 times, the refrigerant pipe 3 generates a more turbulent air flow 4a (causing the air flow 4 to be separated in the latter half of the pipe cross section that becomes an expanded air path) to reduce the heat transfer coefficient on the air side. By increasing it, high heat exchange performance is obtained.

In such a cross fin tube type heat exchanger for refrigeration and air conditioning, the manufacturability and cost of the refrigerant tube itself are reduced.
From the viewpoint of the shape accuracy and the method of fixing the fins to the refrigerant tubes, circular tubes are often used as the refrigerant tubes. The reason for the former tube itself is that tubes with a circular cross section are common and many are made, whereas the reason for the latter fixing method is that the expansion method is most often used for fixing refrigerant tubes and fins. .

In the pipe expansion method, after fins having a substantially flat plate shape having insertion holes are arranged at a close interval, a refrigerant pipe having a diameter slightly smaller than the insertion hole is passed through the insertion hole, and the diameter of the refrigerant pipe is set inside the jig. This is a method in which the tube is enlarged by passing through the fin so as to be in close contact with the insertion hole of the fin. A circular cross section is more suitable for uniformly expanding the tube in this way. Other fixing methods of the refrigerant tube and the fin include inserting the refrigerant tube into the insertion hole of the fin that has been machined smaller, or inserting the refrigerant tube into the insertion hole of the fin, and then deforming the cross section of the refrigerant tube slightly. There is also a non-expansion method such as contacting the fin with a fin. However, also in this case, the refrigerant pipe is only slightly processed based on the circular pipe, so that the refrigerant pipe becomes slightly elliptical, but does not largely deviate from the original circular cross section.

A common example of a refrigerant pipe other than a circular pipe is a flat pipe mainly used for a heat exchanger of an air conditioner for an automobile. This heat exchanger for automotive air conditioners uses a manufacturing method in which fins are sandwiched between flat tubes arranged in the vertical direction and both are fixed and integrated by brazing. From the viewpoints of cost, productivity, and the like, such manufacturing methods and flat tubes are rarely used for home refrigerators and air conditioners.

In recent years, it has been used in refrigeration and air-conditioning equipment from the viewpoint of restricting the amount of CFC-based refrigerant released into the atmosphere for the protection of the ozone layer and suppressing global warming, and the prevention of explosion accidents when flammable refrigerants leak. The importance of reducing the amount of refrigerant used has been emphasized. Correspondingly, in order to reduce the internal volume of the heat exchangers for domestic refrigeration and air conditioning equipment, the most common circular pipes have to be made thinner and the refrigerant pipes have to be reduced in diameter. Although there are few examples, it is considered that the refrigerant pipe is an elliptical pipe or a flat pipe.

A heat exchanger employing an elliptic tube or a flat tube as described above is rarely found for refrigerators, but a heat exchanger for air conditioners is disclosed, for example, in Japanese Patent Application Laid-Open No. 58-125325. And JP-A-58-18144.
No. 0, JP-A-60-108689, and Shokai 6
No. 1-84387, Japanese Unexamined Patent Publication No. Hei 2-133797, and the like, and the arrangement of the refrigerant pipes in these prior arts is not only to improve the performance of the air conditioner but also to suppress the ventilation resistance low. It was assumed that the long axis of the cross section was almost parallel to the air flow.

However, when the diameter of the refrigerant pipe is reduced by the former measure, the internal diameter of the pipe is reduced due to the decrease in diameter, but the effect of the refrigerant pipe on promoting the turbulence of the air flow is reduced, and the heat exchange performance is reduced. The problem appears. For example,
The change in the volume inside the tube is evaluated as being proportional to the square of the diameter (assuming that the inner diameter also decreases at the same ratio as the outer diameter for simplicity). Side heat transfer coefficient is large, so this is evaluated)
National Technical Report on Evaporators for Refrigerators, 30, 5 (1984) 736-744 (National Technical).
Report 30, 5 (1984) pp738-7
44) Based on the experimental data, for air conditioners, it was evaluated by Rich's empirical formula for heat exchangers with flat fins and staggered tube rows shown on page 263 of the heat transfer engineering data (Revised 4th edition) The following table shows a trial calculation of changes in tube internal volume and performance due to the use of small diameter tubes.

[0014]

[Table 1] Table 1 shows that, for a refrigerator evaporator having a seven-row two-stage structure, when the pipe diameter of the refrigerant pipe is changed from φ8 to φ6.35, the internal volume of the pipe is reduced by 36% but the performance is reduced by 10%. When the diameter of the refrigerant pipe is changed from φ7 to φ5.6 in the heat exchanger for an air conditioner having a multi-stage configuration, the internal volume of the pipe is 36%.
It is shown to decrease, but performance is reduced by 5.4%. Considering that the internal volume occupied by the heat exchanger with respect to the entire cycle is about a fraction, taking measures to reduce the diameter of the refrigerant pipe reduces the total amount of refrigerant charged and at the same time considerably reduces the performance of the heat exchanger. It can be seen that a drop occurs.

[0015] The same tendency also occurs when the refrigerant tube is an elliptical tube or a flat tube due to the latter measure. Here, the case where the refrigerant pipe is an elliptical pipe is considered. Regarding the change in the internal volume of the pipe, it is assumed that the pipe is crushed into an ellipse while maintaining the circumference of the original circular pipe. And the inside are assumed to deform similarly). Further, as described above, since the tube is disposed with the major axis of the cross section being substantially parallel to the air flow, the heat exchange performance after deformation has a size (hereinafter referred to as blockage in the present specification) that hinders the flow with respect to the air flow. The evaluation was made assuming that it was equivalent to a circular tube having a diameter equal to the length of the minor axis of the elliptic tube. The following table shows the results calculated in the same manner as in the case of the small diameter tube described above.

[0016]

[Table 2] Table 2 shows that, for a refrigerator evaporator with 7 rows and 2 stages, when the refrigerant tube is changed from a φ8 circular tube to an elliptical tube with a major axis of 10.8 x an end axis of 3.6, the internal volume of the tube decreases by 39%. But performance is 2
In the heat exchanger for an air conditioner having a two-row multi-stage structure, the diameter of the refrigerant pipe is reduced from a circular pipe of φ7 to a major axis of 9.5.
X When an elliptic tube with an end axis of 3.2 is used, the internal volume of the tube is 39%
It has been shown to decrease but performance by 14%.

As in the case of the above-mentioned small-diameter tube, even in the countermeasure for the elliptical tube, the performance of the heat exchanger is reduced at the same time as the internal volume of the tube is reduced. It turns out that it becomes larger than the case of the small diameter tube. As described above, in order to reduce the amount of refrigerant used in refrigeration and air-conditioning equipment, in the conventional method of reducing the diameter of the refrigerant tube of the heat exchanger or changing it to an elliptical tube or a flat tube, the internal volume of the tube is reduced. At the same time, there is a problem that the heat exchanger performance is considerably reduced.

As one of the techniques applicable to the problem of performance degradation accompanying the above-described method of reducing the diameter of a tube or forming an elliptic tube or a flat tube, for example, JP-A-59-95391,
JP-A-59-95392, JP-A-60-1965
No. 99, Japanese Unexamined Patent Publication No. 61-202094, etc., a cylindrical member, a dummy tube, a perforated plate, etc. are arranged immediately before the first row of a heat exchanger for an air conditioner. Showa 6
There is a method of installing a pipe-shaped defrost heater (installed so as to be sandwiched between fins at both end positions in a stepwise direction between several rows) with respect to an evaporator for a refrigerator as disclosed in JP-A-3-279079.

In these methods, since the added member increases the turbulence of the air flow separately from the refrigerant pipe, the heat exchange performance is certainly improved, but has the following limitations. First, in the case of an air conditioner, the range where the disturbance is large is limited to the first half of the heat exchanger because it is installed just before the first row, and when the diameter of the member is small or the opening is large, the disturbance is small. Conversely, if the diameter of the member is large or the opening is small, the turbulence will increase, but the performance improvement will level off due to the decrease in air flow due to the increase in ventilation resistance, and in fact, large performance improvement can not be expected. there were.

In the case of an evaporator for a refrigerator, the defrost heater is a pipe-shaped one connected by a cord, and is installed so as to be inserted later on both sides of the evaporator.
In order to reduce the collapse of the fin, the fin cannot be installed near the center of the fin in the stepwise direction, and the effect of promoting the turbulence of the air flow is limited to the vicinity of both ends of the fin in the stepwise direction.

Among the techniques described above limited to the elliptic tube or the flat tube, particularly applicable to the problem of performance deterioration of the heat exchanger, the target is limited to a heat exchanger for an air conditioner. Japanese Patent Application Laid-Open No. 1-306796 discloses a plurality of elliptic tubes as described in JP-A-63-3183, in which the major axis of the tube cross section and the position of each elliptic tube are inclined with respect to the air flow.
JP, JP-A-1-306797, JP-A-7-9
In a flat tube whose length is equal to the depth of a heat exchanger as shown in Japanese Patent No. 1873, the flat tube is inclined with respect to an air flow or a horizontal plane in order to improve drainage of dew water or the like. is there.

By inclining the major axis of the cross section of the elliptic tube or the flat tube with respect to the air flow, the stepwise width of the refrigerant tube, which is a blockage for the air flow, becomes larger than the length of the minor axis. If the turbulence accelerating effect and performance improvement of such a refrigerant tube can be evaluated by replacing the elliptic tube and the circular tube with the same blockage as in the case of the flat tube described above, the performance as a heat exchanger Improvement can be expected.

However, the first of the above techniques,
In other words, when the major axis of the cross section and the position of the pipe are inclined with respect to the air flow with multiple elliptic pipes, the dead water area of the air flow is greatly increased by hitting the subsequent pipe with little separation of the air flow in the latter half of the pipe cross section. It is intended to be smaller. Therefore, the already described performance evaluation method of replacing the pipe with a circular pipe having the same blockage (assuming that the turbulence is promoted by separation of the air flow in the latter half of the pipe section) cannot be applied in this case. Further, since the turbulence promotion by the refrigerant pipe is not actively used, the performance improvement is not so large as compared with the case where the elliptical pipe is arranged almost parallel to the air flow as described above. Therefore, even if the heat exchanger is formed into an elliptical tube and arranged in this manner, the performance of the heat exchanger may be lower than that of the original circular tube.

In this case, as the long axis of the pipe cross section and the practical inclination angle of the pipe position where the air flow is less likely to be separated, FIG. 5-22 on page 193 of Fluid Engineering (1973) written by Yuichi Asano. The stall angle of the relatively thick wing illustrated in (2) is 22 degrees (the inclination angle at which the air flow separates from the wing surface becomes large), and the elliptical shape practical as a refrigerant pipe has a leading edge for the air flow more than the wing. Considering that the shape is in a blunt range and difficult to peel off, it is considered that about 30 degrees or less is an appropriate range.

The rest of the above techniques, that is, those in which the length of the tube cross-section major axis is close to the depth of the heat exchanger and the flat tube is inclined with respect to the air flow, are slightly inclined for drainage (water droplets are not removed). Although it is possible to fall by the gravitational force by overcoming the capillary force between the fin and the tube, etc.), in this case, too, the effect of promoting the turbulence of the air flow is not positively used. Therefore, for the same reason as that of inclining the major axis and the tube position of the elliptical tube, the refrigerant tube is also used as such a flat tube in which the refrigerant tube is inclined to reduce the amount of refrigerant. Is likely to be degraded.

In this case, as a practical inclination angle of the long axis of the pipe cross section where the air flow is less separated, the boundary layer theory by Schrichting (1979), page 22, FIG. Schlicting Boundary L
aer Theory, 7th Edition (1
979) Considering that the stall angle of the Zhukovsky wing, which is a comparatively thin wing exemplified in p22), is 15 degrees and that it is necessary to drop water droplets smoothly, a reasonable range is about 20 degrees or less. Conceivable.

[0027]

As described above, in the conventional forced convection type heat exchanger for refrigeration and air conditioning, in order to reduce the amount of refrigerant, the refrigerant pipe is formed into a small-diameter pipe or an elliptical or flat pipe to form an internal volume. If the structure is reduced, there is a problem that the heat exchange performance is considerably deteriorated as it is, and none of the proposed prior arts is effective in solving the performance deterioration. SUMMARY OF THE INVENTION An object of the present invention is to provide a forced convection type for refrigeration and air conditioning that can maintain a high heat exchange performance even when a refrigerant pipe of a heat exchanger is formed into a small-diameter tube or an elliptical or flat tube in order to reduce the amount of refrigerant. To provide a heat exchanger.

[0028]

In order to achieve the above object, a first configuration of the heat exchanger according to the present invention comprises a plurality of straight refrigerant tubes arranged substantially orthogonal to the air flow. Department and
A heat exchanger in which a main part is substantially orthogonal to a straight pipe portion of the refrigerant pipe and a large number of fins arranged in parallel with each other at intervals in a pipe axis direction of the straight pipe part of the refrigerant pipe are integrated. Wherein the straight pipe portion of the refrigerant pipe has an elliptical or flat cross-sectional shape, and is disposed such that the major axis of the cross section of the straight pipe portion of the refrigerant pipe is substantially orthogonal to the air flow. is there.

Further, in order to achieve the above object, a second configuration of the heat exchanger according to the present invention comprises a plurality of straight pipe portions of a refrigerant pipe disposed substantially orthogonal to the air flow, In a heat exchanger in which a main part is substantially orthogonal to a straight pipe portion of a refrigerant pipe and a large number of fins are arranged integrally with a plurality of fins arranged side by side at intervals in a pipe axis direction of the straight pipe part of the refrigerant pipe. The straight pipe portion of the refrigerant pipe has an elliptical or flat cross-sectional shape, and the long axis of the cross section of the straight pipe portion of the refrigerant pipe has an inclination angle of 45 degrees or right angle with respect to the airflow. The straight pipe portion of the refrigerant pipe is disposed so as to be inclined such that the inclination direction of the straight pipe portion of the refrigerant pipe is set to have regularity in the row direction and the step direction of the heat exchanger. Things.

Further, in order to achieve the above object, a third configuration of the heat exchanger according to the present invention comprises a plurality of straight pipe portions of a refrigerant pipe disposed substantially orthogonal to the air flow, In a heat exchanger in which a main part is substantially orthogonal to a straight pipe portion of a refrigerant pipe and a large number of fins are arranged integrally with a plurality of fins arranged side by side at intervals in a pipe axis direction of the straight pipe part of the refrigerant pipe. A turbulence accelerating member having a flat cross section that is long in a direction perpendicular to the air flow is provided at a front edge or an intermediate portion of the fin, which is located upstream with respect to the straight pipe portions of each row of the refrigerant pipes. .

In the heat exchanger of the second configuration, the inclination angle is set so that the sign is reversed for each row, or the inclination angle is set so that the sign is reversed in the step direction. In addition, it is preferable that the inclination angle is set so that the positive and negative are reversed in the step direction, and the arrangement pitch of the straight pipe portions of the refrigerant pipes in the step direction is regularly increased or decreased.

In the heat exchanger according to the third configuration, the turbulence promoting member may be installed at a substantially intermediate position in a stepwise direction with respect to a straight pipe portion of the refrigerant pipe immediately downstream. When the heat exchanger is used to cool the air stream to a temperature below freezing, it is preferable that the material of the turbulence promoting member is resin. The first aspect of the present invention
In the heat exchanger according to the second aspect, the turbulence promoting member having a flat cross section that is long in a direction perpendicular to the air flow is provided with a turbulence promoting member upstream of the fins positioned upstream of the straight pipe portions of each row of the refrigerant pipes. It may be installed at the edge or in the middle.

In the heat exchanger of the first type (configuration) of the present invention, the refrigerant pipe is an elliptical pipe or a flat pipe, and the long axis of the pipe section is arranged so as to be substantially perpendicular to the air flow. Things. In order to reduce the amount of refrigerant, the refrigerant pipe is changed from a circular pipe to an elliptical pipe or a flat pipe, and if the straight pipe part of the refrigerant pipe is arranged so as to be substantially perpendicular to the air flow as in this method, The stepwise width of the blockage is the length of the major axis of the cross section of the pipe and is always larger than the diameter of the original circular pipe.
In the case of an elliptical tube or a flat tube having such an arrangement, the curvature of the enlarged air passage in the latter half of the tube cross section becomes steeper than that of the original circular tube, so that the air flow is easily separated. The effect is greater than the original tube. The following table shows the results of a trial calculation of the changes in tube internal volume and heat exchange performance when this method is applied by applying the method already used in the conventional technology.

[0034]

[Table 3] Table 3 shows a refrigerant evaporator having a seven-row, two-stage configuration similar to Tables 1 and 2, in which the refrigerant tube is changed from a φ8 circular tube to an elliptical tube having a major axis of 10.8 × an end axis of 3.6. When the long axis is arranged perpendicular to the air flow, the internal volume of the tube is reduced by 39% but the performance is improved by 8.2%. When the pipe diameter is changed from a φ7 circular pipe to an elliptical pipe having a major axis of 9.5 and an end axis of 3.2, and the major axis of the pipe section is arranged perpendicular to the air flow, the internal volume of the pipe becomes 3
This shows a 9% reduction but a 11.5% improvement in performance. That is, unlike the case of the conventional elliptical tube shown in Table 2, according to the first configuration of the present invention, it is found that the heat exchange performance is improved while the internal volume of the tube is reduced.

The heat exchanger of the second configuration of the present invention is
The refrigerant pipe is made elliptical or flat, and the long axis of the pipe section is inclined at an angle of 45 degrees or more with respect to the air flow, and the direction of the inclination is set with regularity in the row direction and the step direction. Is what you do. When the elliptic tube or the flat tube is inclined with respect to the air flow, the inclination angle at which the air flow does not largely separate on the surface of the tube is 30 as described in the related art.
Degrees or less and 20 degrees or less. In order to improve the heat exchange performance, it is necessary to cause the air flow to separate at the surface of the tube to increase the turbulence in the latter half of the tube cross section. Must be greater than or equal to the upper limit at which the above-mentioned peeling does not occur much.

Further, from the viewpoint of the blockage with respect to the air flow of the refrigerant tube, the flatness of a practical elliptic tube or flat tube is considered to have a ratio of the major axis to the minor axis of the cross section of 2: 1 or more (volume inside the pipe). Is reduced to 81% of the original circular pipe). In order to make the blockage for the air flow of the elliptic pipe having the least flatness and the flattened pipe larger than that of the original circular pipe, an inclination angle of 45 degrees or more is required. With a flatter elliptic tube and a flatter tube, the blockage becomes larger than the original circular tube at a smaller inclination angle. From these facts, if the inclination angle of the long axis of the cross section of the airflow and the pipe in the second system (configuration) of the present invention is set to 45 degrees or more, the turbulence promoting effect is greatly exhibited and the blockage for the airflow is also reduced to the original. Since the number of pipes is equal to or greater than that of a circular pipe, the heat exchange performance can be improved as well as the internal volume of the pipe can be reduced as in the first method of the present invention.

In the second configuration of the present invention, if the inclination directions of the pipe cross sections are the same in both the row direction and the step direction, a drift of the air flow may occur, which may cause a slight decrease in the heat exchange performance. Therefore, it is better to change it with regularity.
For example, the polarity of the inclination angle is reversed for each row, the polarity of the inclination angle is reversed in the step direction, the polarity of the inclination angle is reversed in the step direction, and the arrangement of the straight pipe portions of the refrigerant pipes in the step direction. It is preferable that the pitch is also regularly increased or decreased accordingly.

The heat exchanger of the third configuration of the present invention is
A turbulence-promoting member having a flat cross section that is long in a direction perpendicular to the air flow is provided at a front edge or an intermediate portion of the fin, which is located at an upstream position with respect to the straight pipe portion of each row of the refrigerant pipes. As compared with the cylindrical members for the heat exchanger for the air conditioner and the pipe-shaped defrost heater for the evaporator for the refrigerator as described in the prior art, the turbulence promoting member of the third configuration of the present invention is used. Has a flat cross section that is long in the direction perpendicular to the air flow, and since the members are not connected to each other, it can be installed at any position between the rows of the refrigerant pipes. Since the adjustment can be made by adjusting the width of the members in the direction orthogonal to each other or the number of members installed in the step direction, the heat exchange performance can be further improved.

According to the results of experiments conducted by the inventors, the evaporators for refrigerators having the specifications shown in Table 1 (however, the diameter of the fins is 8 mm, the tubes are arranged in a staggered manner, and the length of the fins in the stepwise direction is 60 mm) are used. At the leading edge, a member with a width of 6 mm is placed
It has been found that the air-side heat transfer coefficient is improved by about 10% at the same wind speed (around 0.6 m / s) by being installed on the inner side of mm. This performance difference is the same as the performance decrease of the refrigerator evaporator due to the 20% reduction in the diameter of the tube as shown in Table 1. Thus, by installing the turbulence accelerating member of the third method (configuration) of the present invention, it is possible to compensate for the decrease in the heat exchange performance that occurs with the reduction of the internal volume of the tube when the diameter of the tube is reduced, etc. Exchange performance can be kept high.

In the third configuration of the present invention, it is preferable that the position of the turbulence promoting member is shifted so as to be substantially intermediate in the stepwise direction with respect to the straight pipe portion of the refrigerant pipe immediately downstream, so that the member and the refrigerant pipe are staggered. It is preferable in terms of performance because it becomes an array. In addition, when a heat exchanger such as a refrigerator evaporator is used in a state where the airflow is cooled below the freezing point and frost is formed, if the material of the turbulence promoting member is made of a resin having a low thermal conductivity, the fin may come into contact with the fins. Even if it is, the turbulence accelerating member does not become so low in temperature and does not frost much, so that there is an effect that frost clogging does not become early for the performance improvement. It is preferable to further apply the turbulence accelerating member of the third configuration to the heat exchanger of the first or second configuration of the present invention, since both of the performance improving effects can be obviously obtained.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to FIGS. First, an embodiment of the first technical means (configuration) of the present invention will be described with reference to FIGS. Embodiment 1 FIG. 1 is a side sectional view of a heat exchanger for a refrigerator, particularly an evaporator, showing a first embodiment of the present invention. The refrigerator heat exchanger 1A shown in FIG.
A is formed into an elliptical tube or a flat tube, and is disposed such that the major axis of the tube cross section is substantially orthogonal to the air flow 4.

Fin 2A which is a component of heat exchanger 1A
The function of the refrigerant pipe 3A and the flow state of the airflows 4 and 4a are basically the same as those already described with reference to FIGS.

The heat exchanger 1A shown in FIG.
The difference from the prior art described in the above is that the refrigerant pipe 3A is an elliptical pipe, and is disposed so that the major axis of its cross section is substantially orthogonal to the air flow 4 (inclination angle θ = 90 °). is there. Therefore, in this refrigerant pipe 3A, the blockage for the air flow 4 becomes longer as the length of the major axis of the pipe cross section as compared with a circular pipe having the same circumferential length, which has already been described in [Means for Solving the Problems]. As described above, the performance as a heat exchanger can be improved as compared with the case of a circular tube.

[Embodiment 2] FIG. 2 shows a second embodiment of the present invention.
It is a side sectional view of the heat exchanger for air conditioners which shows an embodiment. The heat exchanger 1B for an air conditioner shown in FIG.
The refrigerant pipe 3B is formed into an elliptical pipe or a flat pipe, and is disposed so that the major axis of the pipe section is substantially orthogonal to the air flow 4.

Fin 2B as a component of heat exchanger 1B
The function of the refrigerant pipe 3B and the flow state of the airflows 4 and 4a are basically the same as those already described with reference to FIGS.

The heat exchanger 1B shown in FIG.
The difference from the prior art described in the above is that the refrigerant pipe 3B is an elliptical pipe, and is disposed such that the major axis of its cross section is substantially orthogonal to the air flow 4 (inclination angle θ = 90 °). is there. That is, in the refrigerant pipe 3B, the blockage for the airflow 4 becomes longer as the length of the major axis of the pipe cross section as compared with the circular pipe having the same circumference, and the performance as a heat exchanger is larger than that of the circular pipe. Can be improved. Therefore, the heat exchanger according to the first technical means of the present invention can reduce the internal volume of the tube and increase the heat exchange performance even if the refrigerant tube is made elliptical or flat to reduce the amount of refrigerant.

Next, an embodiment of the second technical means (configuration) of the present invention will be described with reference to FIGS. [Embodiment 3] FIG. 3 is a side sectional view of a heat exchanger for a refrigerator, particularly an evaporator, showing a third embodiment of the present invention. The heat exchanger 1C according to the third embodiment shown in FIG.
The refrigerant pipe 3C is formed into an elliptical pipe or a flat pipe, the major axis of the pipe section is inclined at 45 degrees or more with respect to the air flow 4, and the inclination direction of the refrigerant pipe 3C is regular in the column direction A or the step direction B. Is set to have.

In the heat exchanger 1C, the functions of the fins 2C and the refrigerant pipes 3C, which are components of the heat exchanger, and the air flow 4, 4
The flow state of “a” is basically the same as that of the prior art and the first embodiment described above. The refrigerant pipe 3C is an elliptical pipe, and the major axis of its cross section is arranged at an angle of 45 degrees or at right angles to the airflow 4 (inclination angle θ = 45 to 90 °), and its inclination direction alternates in the column direction A. It is made to be reversed.

By inclining the major axis of the cross section of the refrigerant pipe 3C at 45 degrees or more, the air flow 4a is easily separated in the latter half of the cross section of the pipe as described in [Means for Solving the Problems]. The promotion effect is greater, and the blockage against the air flow is greater than that of a circular tube having the same circumference. By alternately reversing the inclination direction of the refrigerant pipes 3C in the row direction A, the air flow 4 flows in a zigzag manner inside the heat exchanger 1C and becomes largely disturbed. Therefore, the performance as a heat exchanger can be improved more than in the case of a circular tube.

[Embodiment 4] FIG. 4 shows a fourth embodiment of the present invention.
It is a side sectional view of the heat exchanger for air conditioners which shows an embodiment. Heat exchanger 1D of the fourth embodiment shown in FIG.
Is to make the refrigerant pipe 3D an elliptical pipe or a flat pipe, incline the major axis of the pipe section with respect to the air flow 4 at 45 degrees or more, and change the inclination direction of the refrigerant pipe 3D to the row direction A or the step direction B.
Is set to have regularity.

In the heat exchanger 1D, the functions of the fins 2D and the refrigerant pipes 3D, which are the components of the heat exchanger, and the air flow 4, 4
The flow state of “a” is basically the same as that of the prior art and the second embodiment described above. The refrigerant pipe 3D is an elliptic pipe, and the major axis of its cross section is inclined at an angle of 45 degrees or at right angles to the airflow 4 (inclination angle θ = 45 to 90 °), and is arranged.
The inclination direction is set to be opposite to the column direction A.

By inclining the major axis of the cross section of the refrigerant pipe 3D to 45 degrees or more, as described above, the air flow 4a is easily separated in the latter half of the cross section of the pipe, and the turbulence promoting effect is increased. The blockage with respect to the air flow is larger than that of a circular tube having the same size. By alternately reversing the inclination direction of the refrigerant pipes 3D in the row direction A, the air flow 4 flows in a zigzag manner inside the heat exchanger and becomes largely disturbed. Therefore, the performance as a heat exchanger can be improved more than in the case of a circular tube.

[Embodiment 5] FIG. 5 shows a fifth embodiment of the present invention.
FIG. 2 is a side sectional view of a heat exchanger for a refrigerator, particularly an evaporator, showing the embodiment. Heat exchanger 1E for refrigerator shown in FIG.
Is to make the refrigerant pipe 3E an elliptical pipe or a flat pipe, incline the major axis of the pipe cross section with respect to the air flow 4 at 45 degrees or more, and further, unlike the example of FIG. It is set so that it is alternately reversed not only in the direction A but also in the step direction B. 2E indicates a fin.

In the heat exchanger 1E, the air flow 4 is disturbed and slightly deflected by the inclination of the refrigerant pipe 3E. However, if the inclination direction of the refrigerant pipe 3E is not deviated in a specific direction, the air flow 4 is deflected. There is no slight decrease in heat exchange performance due to heat. Therefore, the effect of the inclined refrigerant pipe 3E on the internal volume of the pipe and the heat exchange performance in this case is as follows.
This is exactly the same as in the case of the third embodiment.

[Embodiment 6] FIG. 6 shows a sixth embodiment of the present invention.
It is a side sectional view of the heat exchanger for air conditioners which shows an embodiment. The heat exchanger 1F shown in FIG. 6 is configured such that the refrigerant tube 3F is formed into an elliptical tube or a flat tube, and the major axis of the tube cross section is inclined at 45 degrees or more with respect to the airflow 4, and further, unlike the example of FIG. The inclination direction of the refrigerant pipe 3F is set so as to be alternately reversed not only in the column direction A but also in the step direction B. 2F indicates a fin.

In the heat exchanger 1F, the air flow 4 is disturbed and slightly deflected by the inclination of the refrigerant pipe 3F. However, if the inclination direction of the refrigerant pipe 3F is not deviated in a specific direction, the air flow 4 is deflected. There is no slight decrease in heat exchange performance due to heat. Therefore, the effect of the inclined refrigerant pipe 3F on the internal volume of the pipe and the heat exchange performance in this case is exactly the same as in the case of the fourth embodiment.

[Embodiment 7] FIG. 7 shows a seventh embodiment of the present invention.
FIG. 2 is a side sectional view of a heat exchanger for a refrigerator, particularly an evaporator, showing the embodiment. In the heat exchanger 1G shown in FIG. 7, the refrigerant pipe 3G is formed into an elliptical pipe or a flat
In contrast, the major axis of the pipe section is inclined at 45 degrees or more,
The direction of inclination of the refrigerant pipe 3G is set to be the same in the column direction A and opposite in the step direction B. 2G indicates a fin.

In the heat exchanger 1G, the arrangement pitch C of the refrigerant pipes 3G in the step direction B is set wider in the portion where the air path is tapered in accordance with the deflection of the air flow 4 due to the inclination of the refrigerant pipes 3G. It is possible to reduce a slight decrease in the heat exchange performance due to the bias of 4. Therefore, the effect on the tube internal volume and the heat exchange performance of the inclined refrigerant tube 3G in this case is exactly the same as in the case of the third embodiment.

[Embodiment 8] FIG. 8 shows an eighth embodiment of the present invention.
It is a side sectional view of the heat exchanger for air conditioners which shows an embodiment. The heat exchanger 1H shown in FIG. 8 is configured such that the refrigerant pipe 3H is formed into an elliptical pipe or a flat pipe, the long axis of the pipe section is inclined at 45 degrees or more with respect to the air flow 4, and the refrigerant pipe 3H
The inclination direction of H is set to be the same in the column direction A and alternately reversed in the step direction B.
In the arrangement pitch C, the part where the air path is tapered due to the inclination of the refrigerant pipe 3H is wide, and the part where the air path is enlarged is narrow. 2
H indicates a fin.

In the heat exchanger 1H, the inclination direction of the refrigerant pipes 3H is set to be the same in the column direction A and alternately reversed in the step direction B, and the arrangement pitch C of the refrigerant pipes 3H in the step direction B is set. Since the portion where the air path is tapered due to the inclination of the refrigerant pipe 3H is set appropriately widely, it is possible to reduce a slight decrease in the heat exchange performance due to the bias of the air flow 4. Therefore,
The effect of the inclined refrigerant pipe 3H on the internal volume of the pipe and the heat exchange performance in this case is exactly the same as in the case of the fourth embodiment. As described above, the heat exchanger to which the second technical means of the present invention is applied makes it possible to increase the heat exchange performance as well as to reduce the internal volume of the pipe even if the refrigerant pipe is made elliptical or flat to reduce the amount of refrigerant. it can.

Next, an embodiment of the third technical means (configuration) of the present invention will be described with reference to FIGS. Ninth Embodiment FIG. 9 is a side sectional view of a heat exchanger for a refrigerator, particularly an evaporator, showing a ninth embodiment of the present invention. The heat exchanger 1I shown in FIG. 9 differs from the heat exchanger shown in FIG. 14 in that a turbulence promoting member 5 having a flat cross section that is long in a direction orthogonal to the airflow 4 is provided in each row of the refrigerant pipes 3. This is a heat exchanger provided at the front edge or middle of the fin 2 located upstream of the straight pipe portion.

In the heat exchanger 1I, the functions of the fins 2 and the refrigerant pipes 3, which are the components of the heat exchanger, and the flow states of the air flows 4 and 4a are basically the same as those of the conventional technology. However, the turbulence accelerating members 5 having a flat cross section are provided so as to be in contact with the front edges of the fins 2 in each row of the refrigerant pipes 3, and these turbulence accelerating members 5 act to greatly disturb the air flow 4 like the refrigerant pipes 3. I do. Therefore, the performance as a heat exchanger can be improved compared to before the turbulence promoting member 5 is installed.

[Embodiment 10] FIG. 10 is a side sectional view of a heat exchanger for an air conditioner according to a tenth embodiment of the present invention. The heat exchanger IJ shown in FIG.
In contrast to the configuration of the heat exchanger shown in FIG. 1, the turbulence promoting member 5 having a flat cross section that is long in a direction orthogonal to the air flow 4 is provided with a front edge of the fin 2 at an upstream position with respect to the straight pipe portion of each row of the refrigerant pipes 3. It is provided in the middle.

In the heat exchanger IJ, the functions of the fins 2 and the refrigerant pipes 3, which are the components of the heat exchanger, and the flow states of the airflows 4 and 4a are basically the same as those of the prior art. But,
The turbulence promoting members 5 having a flat cross section are provided so as to be in contact with the front edges of the fins 2 in each row of the refrigerant pipes 3, and these turbulence promoting members 5 have a function of greatly disturbing the air flow 4 similarly to the refrigerant pipes 3. .

In this way, even if the refrigerant pipe 3 is made thinner or elliptical or flattened in the conventional configuration and the heat exchange performance is deteriorated, the performance deterioration is eliminated by the turbulence promoting member 5. Therefore, the heat exchange performance can be kept equal to or higher than that of the circular pipe before being formed into a small diameter pipe or an elliptical or flat pipe.
Therefore, the heat exchanger according to the third technical means of the present invention can reduce the internal volume of the pipe and improve the heat exchange performance even if the refrigerant pipe is made elliptical or flat to reduce the amount of refrigerant.

[Embodiment 11] FIG. 11 is a side sectional view of a heat exchanger for a refrigerator, particularly an evaporator, showing an eleventh embodiment of the present invention. The heat exchanger 1K shown in FIG.
This is a combination of the first technical means and the third technical means of the present invention. That is, the refrigerant pipe 3A is formed into an elliptical pipe or a flat pipe, and the air flow 4 is supplied to the heat exchanger 1K disposed so that the major axis of the pipe cross section is substantially orthogonal to the air flow 4.
A turbulence accelerating member 5 having a flat cross section that is long in a direction perpendicular to the above is provided at the front edge or middle of the fin 2A located upstream with respect to the straight pipe portion of each row of the refrigerant pipes 3A.

As is clear from the above description, in the heat exchanger 1K, even if the refrigerant pipe is made elliptical or flat to reduce the amount of refrigerant, it is possible to increase the heat exchange performance while reducing the internal volume of the pipe. it can.

[Twelfth Embodiment] FIG. 12 is a side sectional view of a heat exchanger for an air conditioner showing a twelfth embodiment of the present invention. A heat exchanger 1L shown in FIG. 12 is a heat exchanger combining the first technical means and the third technical means of the present invention. That is, the refrigerant pipe 3B is formed into an elliptical pipe or a flat pipe, and the heat exchanger 1L arranged so that the major axis of the pipe cross section is substantially perpendicular to the air flow 4 is provided with a long flat shape in the direction perpendicular to the air flow 4. A turbulence accelerating member 5 having a cross section of a shape is provided at a front edge or an intermediate portion of the fin 2B located upstream with respect to the straight pipe portion of each row of the refrigerant pipes 3B.

In the heat exchanger 1L for the air conditioner, as is clear from the above description, even if the refrigerant pipe is made elliptical or flat for the purpose of reducing the refrigerant, the heat exchange with the pipe inner volume is reduced. Performance can be improved.

[0070]

As described above in detail, according to the present invention, even if the refrigerant pipe of the heat exchanger is reduced in diameter or is made elliptical or flat to reduce the amount of refrigerant, the heat exchange performance can be improved. , A forced convection type heat exchanger for refrigeration and air conditioning, which can maintain a high air temperature.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a heat exchanger for a refrigerator, showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of a heat exchanger for an air conditioner according to a second embodiment of the present invention.

FIG. 3 is a side sectional view of a heat exchanger for a refrigerator according to a third embodiment of the present invention.

FIG. 4 is a side sectional view of a heat exchanger for an air conditioner according to a fourth embodiment of the present invention.

FIG. 5 is a side sectional view of a heat exchanger for a refrigerator according to a fifth embodiment of the present invention.

FIG. 6 is a side sectional view of a heat exchanger for an air conditioner according to a sixth embodiment of the present invention.

FIG. 7 is a side sectional view of a heat exchanger for a refrigerator, showing a seventh embodiment of the present invention.

FIG. 8 is a side sectional view of a heat exchanger for an air conditioner, showing an eighth embodiment of the present invention.

FIG. 9 is a side sectional view of a heat exchanger for a refrigerator according to a ninth embodiment of the present invention.

FIG. 10 is a side sectional view of a heat exchanger for an air conditioner, showing a tenth embodiment of the present invention.

FIG. 11 is a side sectional view of a heat exchanger for a refrigerator showing an eleventh embodiment of the present invention.

FIG. 12 is a side sectional view of a heat exchanger for an air conditioner according to a twelfth embodiment of the present invention.

FIG. 13 is a perspective view showing a general heat exchanger for a refrigerator.

FIG. 14 is a side sectional view of FIG. 13;

FIG. 15 is a perspective view showing a heat exchanger for a general air conditioner.

FIG. 16 is a side sectional view of FIG. 15;

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1
I, 1J: heat exchanger, 2, 2A, 2B, 2C, 2D, 2
E, 2F, 2G, 2H ... fin, 3, 3A, 3B, 3
C, 3D, 3E, 3F, 3G, 3H ... refrigerant pipe, 4, 4a
... air flow, 5 ... turbulence promoting member.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiro Matsuoka 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside of Hitachi, Ltd. Address: In the Refrigeration Division, Hitachi, Ltd.

Claims (9)

[Claims] 1. A refrigerant pipe having a plurality of straight pipes disposed so as to be substantially orthogonal to an air flow, a main part being substantially orthogonal to the straight pipe of the refrigerant pipe, and a straight pipe of the refrigerant pipe. In a heat exchanger configured by integrating a large number of fins arranged side by side while maintaining an interval in the pipe axis direction, the straight pipe portion of the refrigerant pipe has an elliptical or flat cross-sectional shape, and The heat exchanger according to claim 1, wherein a long axis of a cross section of the straight pipe portion of the refrigerant pipe is disposed so as to be substantially orthogonal to the air flow. 2. A refrigerant pipe having a plurality of straight pipes disposed substantially orthogonal to an air flow, a main part substantially orthogonal to the straight pipe of the refrigerant pipe, and a straight pipe of the refrigerant pipe. In a heat exchanger configured by integrating a large number of fins arranged side by side while maintaining an interval in the pipe axis direction, the straight pipe portion of the refrigerant pipe has an elliptical or flat cross-sectional shape, and The straight pipe section of the refrigerant pipe is disposed so as to be inclined such that the long axis of the cross section of the straight pipe section of the refrigerant pipe with respect to the air flow is 45 degrees or a right angle. A heat exchanger characterized in that the inclination direction of the straight pipe portion of the pipe is set so as to have regularity in the row direction and the step direction of the heat exchanger. 3. The inclination angle of the cross section of the straight pipe portion of the refrigerant pipe held with respect to the airflow is set so that the polarity is reversed for each row. A heat exchanger. 4. The apparatus according to claim 2, wherein a major axis of a cross section of the straight pipe portion of the refrigerant pipe is set such that an inclination angle held by the air flow with respect to the air flow is opposite in the step direction. A heat exchanger. 5. An apparatus according to claim 2, wherein a major axis of a cross section of the straight pipe portion of the refrigerant pipe has an inclination angle held with respect to the air flow set so that the positive and negative are reversed in the stepwise direction. A heat exchanger, wherein the arrangement pitch of the straight pipe portions of the refrigerant pipes in the step direction is regularly increased and decreased. 6. A refrigerant pipe having a plurality of straight pipes disposed substantially orthogonal to the air flow, a main part substantially orthogonal to the straight pipe of the refrigerant pipe, and a straight pipe of the refrigerant pipe. In a heat exchanger configured by integrating a large number of fins arranged side by side while maintaining an interval in the pipe axis direction, the turbulence promoting member having a flat cross section that is long in a direction orthogonal to the air flow, A heat exchanger provided at a front edge or an intermediate portion of the fin, which is located upstream of a straight pipe portion of each row of the refrigerant pipes. 7. The apparatus according to claim 6, wherein the turbulence promoting member is provided at a substantially intermediate position in a stepwise direction with respect to a straight pipe portion of the refrigerant pipe located immediately downstream. Heat exchanger. 8. The turbulence promoting member according to claim 6, wherein the turbulence promoting member is made of resin when the heat exchanger is used in a state where the air flow is cooled below the freezing point. Heat exchanger. 9. The cooling pipe according to claim 1, wherein a turbulence promoting member having a flat cross section that is long in a direction perpendicular to the air flow is provided upstream of a straight pipe portion of each row of the refrigerant pipes. A heat exchanger provided at a front edge or an intermediate portion of the fin as a position.