JP2014095524A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of elongating its service life by improving corrosion resistance of a heat exchanger, and reducing manufacturing costs of the heat exchanger.SOLUTION: An air conditioner includes a heat exchanger 1 composed of a plurality of aluminum flat tubes 20. The flat tube 20b disposed in a lower region d in the gravity direction, among the plurality of flat tubes 20 is composed of a flat tube with a specification having corrosion resistance higher than that of the flat tube 20a disposed at an upper region u. Or the flat tube disposed in a place of higher air velocity is composed of a flat tube of a specification having corrosion resistance higher than the flat tube disposed in a place of low air velocity. Or the plurality of flat tubes are disposed in the gravity direction, and a lower part of these flat tubes is constructed to have corrosion resistance higher than that of the upper part.

Description

The present invention relates to an air conditioner including a heat exchanger using an aluminum tube, and particularly suitable for an air conditioner such as a room air conditioner or a packaged air conditioner having a heat exchanger using an aluminum flat tube. Is.
In this specification and claims, the term “aluminum” is used to include aluminum and its alloys.

  Currently, cross fin tube heat exchangers are frequently used as heat exchangers used in air conditioners. This cross fin tube type heat exchanger has a hole with a restriction at a predetermined position of a strip-shaped aluminum fin, and after inserting a copper-made circular heat transfer tube (pipe-shaped heat transfer tube), It is manufactured by mechanically expanding the heat transfer tube.

  On the other hand, for low cost, price stability, small size, light weight, etc., instead of the conventional copper heat transfer tube, the heat transfer tube is replaced with an aluminum flat tube, and the flat tube, fins and header are brazed. Parallel flow heat exchangers that are manufactured by attaching them have been developed. In particular, in an air conditioner for an automobile, an aluminum heat exchanger that can be reduced in size and weight has been adopted in order to improve fuel efficiency and expand a living space.

  Aluminum generally has a higher corrosion resistance than iron or the like because an alumite layer of an oxide film is naturally formed on the surface. However, if there is a substance that affects the oxide film such as chlorine, corrosion resistance is inferior, and in this case, pitting corrosion that deeply erodes in the thickness direction of the flat tube constituting the heat exchanger may occur. . When pitting corrosion occurs in the flat tube, there is a possibility that a through hole is made in the flat tube and the internal high-pressure refrigerant is leaked.

  Air conditioners are often used in areas with a high salinity in the atmosphere near the coast or in high-temperature and high-humidity areas. In this case, in particular, the heat exchanger for the outdoor unit that constitutes the air conditioner is to be installed in a place with severe outdoor conditions in terms of corrosion such as a place where there is a lot of salt in the atmosphere or a place where the temperature and humidity are high. Become.

  In addition, chlorofluorocarbon refrigerants are used in current air conditioners. For example, Freon R410A is widely used in room air conditioners, but its global warming potential (GWP) is relatively high at about 2000. Therefore, the refrigerant leakage due to the heat exchanger malfunction affects not only the malfunction of the air conditioner but also the environmental problem.

  For this reason, when the heat exchanger of the air conditioner is made of aluminum, in order to prevent refrigerant leakage, high corrosion prevention (corrosion resistance), especially pitting corrosion is prevented during the set service life of the air conditioner. Is required.

  As a measure to improve the corrosion resistance against salt damage in aluminum heat exchangers, a flat tube is sprayed with zinc on its surface, and a circular tube is coated with a sacrificial anode layer on the surface of an aluminum core such as a multilayer aluminum clad tube. There is technology to add.

  This is to provide a sacrificial anode layer by providing a layer of a base material having a lower potential than the core material on the surface of the aluminum core material, so that the progress of pitting corrosion is only the sacrificial anode layer so that the aluminum core material is not corroded. To do.

Known techniques for providing a sacrificial anode layer on the surface of an aluminum core include those described in JP-A-4-15496 (Patent Document 1) and JP-A 2009-1445020 (Patent Document 2).
Patent Document 1 discloses a zinc spray technique for providing a sacrificial anode layer on the surface of an aluminum flat tube.

  Patent Document 2 discloses an invention in which zinc spraying is performed from the front side edge in the width direction of each aluminum flat tube to a predetermined position with respect to the entire width. The thing of this patent document 2 is targeting the heat exchanger of the air conditioner for motor vehicles, and improves corrosion resistance by performing a zinc spraying to the front side area | region of the said flat tube used as the front of the advancing direction of a motor vehicle. ing. Moreover, the thickness of the tube wall is reduced by reducing the thickness of the flat tube by reducing the thickness of the tube wall by not spraying zinc on the back side of the flat tube or by spraying zinc thinner than the front side.

JP-A-4-15496 JP 2009-14050 A

The thing of the said patent document 1 is only disclosed the zinc spraying technique for providing a sacrificial anode layer in the surface of the flat tube made from aluminum, and heat exchange is carried out by combining many such flat tubes of the same corrosion resistance specification. In the case of constituting a heat exchanger, if the progress of corrosion of some of the flat tubes is fast, the life of the heat exchanger is determined thereby, and there is a problem that the life of the heat exchanger is shortened.
Moreover, in order to prolong the lifetime of a flat tube, when the thing with the specification with high corrosion resistance was employ | adopted for all the flat tubes which comprise a heat exchanger, there existed a subject which the manufacturing cost of a heat exchanger increased.

  In the thing of the said patent document 2, although zinc spraying is given to the front side area | region of the said flat tube used as the front of the advancing direction of a motor vehicle, and corrosion resistance is improved, the same corrosion resistance is applied to all the flat tubes which comprise a heat exchanger. The thing of specification is employ | adopted and the subject similar to the thing of the said patent document 1 exists.

  An object of the present invention is to obtain an air conditioner that can improve the corrosion resistance of a heat exchanger to extend its life and can also reduce the manufacturing cost of the heat exchanger.

  In order to achieve the above object, the present invention is an air conditioner including a heat exchanger composed of a plurality of aluminum tubes, and the gravitational direction of the plurality of tubes constituting the heat exchanger. The pipe arranged below is constituted by a pipe having a specification having higher corrosion resistance than the pipe arranged above.

  Another feature of the present invention is an air conditioner including a heat exchanger composed of a plurality of aluminum tubes, and is arranged in a place where the wind speed is high among the plurality of tubes constituting the heat exchanger. In other words, the pipe is made of a pipe having a specification that has higher corrosion resistance than a pipe placed in a place where the wind speed is low.

  Still another feature of the present invention is an air conditioner including a heat exchanger composed of a plurality of aluminum tubes, wherein each of the plurality of tubes constituting the heat exchanger is oriented in the direction of gravity. The lower part of the pipe is configured to have higher corrosion resistance than the upper part.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect by which the corrosion resistance of a heat exchanger can be improved and the lifetime can be extended, and also the air conditioner which can also reduce the manufacturing cost of a heat exchanger is obtained.

The front view which shows the heat exchanger used for Example 1 of the air conditioner of this invention. Sectional drawing explaining the shape of the flat tube used for the heat exchanger shown in FIG. The schematic perspective view of the outdoor unit explaining the wind velocity distribution of the air in the outdoor heat exchanger in the outdoor unit of an air conditioner, and the chlorine ion extraction location in a field test. It is a figure explaining the fin shape used for the heat exchanger shown in FIG. 1, and is the front view (A) of a heat exchanger at the time of employ | adopting a strip-shaped straight fin, and aa arrow view of this (A) figure Figure (B). It is a figure explaining the other fin shape used for the heat exchanger shown in FIG. 1, and the front view (A) of a heat exchanger at the time of employ | adopting a corrugated fin, and the bb arrow of this (A) figure Visual view (B). The schematic sectional side view explaining the example at the time of employ | adopting the heat exchanger used for the air conditioner of this invention for the indoor unit of a room air conditioner. The schematic perspective view explaining the example at the time of employ | adopting the heat exchanger used for the air conditioner of this invention for the indoor unit of a package air conditioner. Sectional drawing which shows the flat tube used for the heat exchanger of Example 2 of the air conditioner of this invention. The front view which shows the heat exchanger used for Example 3 of the air conditioner of this invention. The perspective view which shows the heat exchanger used for Example 4 of the air conditioner of this invention. Sectional drawing explaining the structure of the upper flat tube 20e shown in FIG. 10, and the lower flat tube 20f. The front view which shows the heat exchanger used for Example 5 of the air conditioner of this invention.

  Hereinafter, specific examples of the air conditioner of the present invention will be described with reference to the drawings. Note that, in each drawing, the portions denoted by the same reference numerals indicate the same or corresponding portions.

  A first embodiment of an air conditioner according to the present invention will be described with reference to FIGS. 1 is a front view showing a heat exchanger used in Embodiment 1 of an air conditioner of the present invention, FIG. 2 is a cross-sectional view for explaining the shape of a flat tube used in the heat exchanger shown in FIG. 3 is a schematic perspective view of the outdoor unit for explaining the air velocity distribution in the outdoor heat exchanger in the outdoor unit of the air conditioner and the chlorine ion extraction location in the field test. FIG. 4 is a view for explaining the fin shape in the heat exchanger used in the first embodiment.

  FIG. 1 is a front view of an aluminum heat exchanger as viewed from the front portion in the ventilation direction. The heat exchanger 1 is a pair of left and right hollow refrigerant headers 10 and 11 installed in parallel and vertically. (All made of aluminum) and a plurality of flat tubes 20 (all made of aluminum) provided between the refrigerant headers 10 and 11 and connected so as to communicate the refrigerant headers 10 and 11. Yes. The plurality of flat tubes 20 are stacked in the vertical direction (gravity direction), and each flat tube 20 is installed in the horizontal direction. A large number of aluminum fins 30 are provided between the adjacent flat tubes 20 with a predetermined gap (interval). The refrigerant headers 10, 11, the flat tubes 20, and the fins 30 are put into a furnace in a state of being assembled together, and are brazed and integrated.

When the heat exchanger 1 of FIG. 1 is operated as a condenser, a gaseous refrigerant flows into the refrigerant header 10 from a refrigerant gas pipe 12 of a refrigeration cycle (not shown). In the flat tube 20, the heat is exchanged with the air in order, and the liquid is finally liquefied and flows out to the refrigerant liquid pipe 13 of the refrigeration cycle connected to the refrigerant header 11.
When the heat exchanger 1 is operated as an evaporator, conversely, a gas-liquid two-phase refrigerant having a low degree of freshness after passing through the expansion valve flows from the refrigerant liquid pipe 13 and sequentially evaporates in the flat tube 2 into a gaseous state. The resulting refrigerant flows out from the refrigerant header 10 to the refrigerant gas pipe 12.

  By causing air to flow between the fins 30, supplying the refrigerant to the refrigerant headers 10, 11 and flowing the refrigerant through the flow path in the flat tube 20, heat exchange can be performed between the air and the refrigerant. it can.

  FIG. 2 is a view for explaining the cross-sectional shape of the flat tube 20 used in the heat exchanger 1 shown in FIG. 1, and the flat tube 20a shown in FIG. A flat tube 20b shown in FIG. 2B is a flat tube arranged in a region below the gravitational direction (vertical direction) shown in FIG. Show.

  Each flat tube 20 (20a, 20b) has a plurality of partitioned spaces, as shown in the cross-sectional views of FIGS. 2A and 2B, and these spaces communicate with each other in the longitudinal direction of each flat tube 20. Thus, the refrigerant flow paths 21a and 21b are formed.

Further, sacrificial anode layers 22a and 22b are provided on the surfaces of the flat tubes 20a and 20b. The sacrificial anode layers 22a and 22b are formed of a metal whose potential is lower than that of the aluminum cores 23a and 23b forming the refrigerant flow paths (spaces) 21a and 21b so that the sacrificial anticorrosive effect can be obtained. I have to. That is, the flat aluminum tube 20 is usually manufactured by extrusion molding. Zinc spraying is performed on the surface of the flat aluminum tube after the extrusion molding, and is diffused by the heat at the time of brazing as described above. Forming a diffusion layer. Alternatively, the flat tube 20 may be formed of an aluminum clad layer retrofitted with another aluminum layer.
FIG. 2 shows an example in which the cross-sectional shapes of the refrigerant flow paths (spaces) 21a and 21b are rectangular, but the refrigerant flow paths may be triangular or circular.

  The flat tube 20a arranged in the upper region u in the direction of gravity of the heat exchanger 1 shown in FIG. 1 and the flat tube 20b arranged in the lower region d are shown in FIGS. As shown, the thicknesses H1 and H2 are substantially the same (H1 = H2). Also, the aluminum thickness tw2 including the sacrificial anode layer 22b of the flat tube 20b disposed in the lower region d is the aluminum thickness tw2 including the sacrificial anode layer 22a of the flat tube 20a disposed in the upper region u. It is configured to be larger than the wall thickness tw1. For this reason, the height of the refrigerant flow path 21a is higher than the refrigerant flow path 21b (hc1> hc2). The sacrificial anode layers 22a and 22b are formed such that the thickness te2 of the flat tube 20b disposed in the lower region d is greater than the thickness te1 of the flat tube 20a disposed in the upper region u. Thicker (te2> te1).

Thus, in this embodiment, one aluminum heat exchanger is composed of at least two or more types of flat tubes 20a and 20b having different corrosion resistance specifications (particularly salt damage corrosion resistance specifications).
Note that the flat tubes 20a and 20b having different corrosion resistance specifications may change the thickness of the aluminum cores 23a and 23b instead of changing the thickness of the sacrificial anode layers 22a and 22b. Both the thickness of the anode layers 22a and 22b and the thickness of the aluminum cores 23a and 23b may be changed.

Next, experimental results using the outdoor unit of the room air conditioner will be described with reference to FIG. FIG. 3 shows an outdoor unit 40 of a room air conditioner, and a field monitor test regarding actual corrosion was performed using the heat exchanger 1 made of aluminum for the outdoor unit 40. This field monitor test was conducted by installing an outdoor unit 40 on a veranda of a house for several years in Okinawa, where salt damage is relatively high in Japan and considered high temperature and high humidity. The outdoor unit used in this experiment was equipped with an L-shaped heat exchanger 1 as shown in FIG.
In the outdoor unit 40, in addition to the heat exchanger 1, a compressor 50 constituting a refrigeration cycle, a blower fan 60 constituted by an axial fan (propeller fan), and the like are also housed.

  The outline of the wind speed distribution in the outdoor unit 40 is shown by curves 14a and 14b in FIG. A curve 14a indicates the wind speed distribution in the left-right direction (horizontal direction, x-axis direction) at the outlet of the heat exchanger 1, and a curve 14b indicates the wind speed distribution in the vertical direction (gravity direction, y-axis direction). As shown by these curves 14a and 14b, the wind speed distribution of the air sucked into the heat exchanger 1 is greatly affected by the mounted axial fan (the blower fan 60), and the wind speed near the center of the axial fan is large. Is high.

Next, the results of this field monitor test will be described.
After the field monitoring period, chlorine ions were extracted from the surface of the aluminum fin 30 of the heat exchanger 1. The extraction of the chlorine ions was performed by putting a sample obtained by cutting out the fin 30 made of aluminum and pure water into a container and vibrating with ultrasonic waves. Further, the extracted chlorine ions were measured by ion chromatography. The parts of the heat exchanger 1 from which the chlorine ions have been extracted are nine parts A to I shown in FIG.

  Table 1 shows the measurement results of the chlorine ion concentrations at the nine locations in the heat exchanger 1. The numerical values in Table 1 are shown in a dimensionless manner with the maximum value (location: F) among the nine locations where chlorine ions were measured as a parameter.

  From the results in Table 1, it can be seen that the lowermost portion (lower region) in the vertical direction of the heat exchanger 1 has the highest chlorine ion concentration. Moreover, it turns out that the area | region of the center part of a fan has high chlorine ion concentration in the left-right direction of a heat exchanger.

  From the experimental results shown in Table 1, it can be seen that the higher the wind speed of the heat exchanger 1, the more chlorine in the air is attached to the fins 30 made of aluminum. Moreover, the chlorine adhering to the fin surface is combined with the moisture condensed on the fin surface, and flows down by the gravitational action, and the moisture is repeatedly evaporated. Thus, it is considered that the chlorine ion concentration is highest in the lowermost part of the heat exchanger 1 in the vertical direction by depositing and concentrating chlorine at the lowermost part of the heat exchanger 1.

  Chlorine deposited on the surface of the fin 30 of the heat exchanger 1 promotes pitting corrosion of the flat tube 20 when moisture is contained by condensed water, rainwater, or the like. Also in this field monitor test result, the pitting corrosion of the lowermost aluminum portion of the heat exchanger 1 was particularly remarkable.

  From this experimental result, in Example 1, it can be seen that the portion where a lot of chlorine adheres and pitting corrosion easily proceeds is the positions of the lower positions F, C, and I in the vertical direction of the heat exchanger 1. Accordingly, the flat tube 20 disposed in the region d below the heat exchanger 1 is configured by the flat tube 20b having a high corrosion resistance specification, that is, a specification having a high corrosion resistance, as shown in FIG. Moreover, about the flat tube 20 arrange | positioned in the area | region u above the heat exchanger 1, since the adhesion amount of chlorine is comparatively small, corrosion resistance is comparatively lower than the heat exchanger tube 20b shown to (B) of FIG. Although it becomes a specification, it is comprised with the flat pipe | tube 20a whose corrosion resistance specification shown to (A) of FIG.

  By configuring in this way, the corrosion resistance of the heat exchanger 1 can be improved and its life can be extended, and the flat tube 20a having a relatively low corrosion resistance is used for the upper flat tube 20, so The manufacturing cost of the heat exchanger 1 can also be reduced.

  In addition, a large amount of chlorine tends to adhere to the vicinity of the center in the up-down direction and the center in the left-right direction where the wind speed of the heat exchanger 1 increases, and pitting corrosion tends to proceed. Therefore, it is preferable that the flat tube 20 disposed in the region where the wind speed is high is also configured by a flat tube 20b having a specification having higher corrosion resistance than the flat tube 20 disposed in the region where the wind speed is low. That is, if it demonstrates in FIG. 3, it is good to employ | adopt the flat tube 20b of a specification with high corrosion resistance also about the flat tube 20 installed in the part corresponding to E and H. FIG. In the case of the flat tube 20 at the same height, the amount of chlorine attached is large near the center in the left-right direction of the heat exchanger 1, and the amount of chlorine attached is relatively small on both side portions. The thickness of 22b may be thick near the center of the flat tube 20 and thin on the left and right sides.

  The configuration of the fins 30 used in the heat exchanger 1 shown in FIG. 1 will be described in detail with reference to FIG. 4A is a front view (A) of the heat exchanger 1 employing the strip-shaped straight fins 30, and FIG. 4B is a view taken along the line aa in FIG.

  The fins 30 are formed of aluminum strip-like straight fins, and are inserted into the fins 30 so as to sandwich the flat tube 20 in a rectangular plate-shaped material as shown in FIG. The slit portion 30a and an uneven portion 30b formed between the slit portions 30a for improving the heat exchange performance are provided. The fins 30 are arranged side by side so as to be stacked at a predetermined interval, and a plurality of the flat tubes 20 are inserted into the slit portions 30a of the numerous fins 30.

  In addition, the structure and shape of the fin 30 are determined in consideration of corrosion resistance, frost resistance, drainage properties, and the like. For example, a sacrificial anode layer is also provided for the fins 30 in order to improve the corrosion resistance, or the condensed water condensed by the fins 30 flows smoothly downward.

  In the present embodiment, the fin 30 is described as an example of a strip-shaped straight fin. However, the fin 30 is not limited to the strip-shaped straight fin, and a corrugated fin 31 as shown in FIG. You may comprise.

  That is, FIG. 5 is a diagram for explaining another fin shape used in the heat exchanger 1 shown in FIG. 1, and a front view (A) of the heat exchanger when a corrugated fin is adopted, and this (A ) It is a bb arrow line view of a figure. In the example shown in FIG. 5, fins 31 formed by bending a thin aluminum plate into a corrugated plate shape (corrugated shape) are inserted between the flat tubes 20 and brazed. In addition, as shown in FIG. 5B, the corrugated fin 31 is formed with fine slits 31a to improve the heat exchange performance.

  As described above, in the present embodiment, the fins constituting the heat exchanger 1 can employ various fin shapes such as strip-shaped straight fins shown in FIG. 4 and corrugated fins shown in FIG. is there. 4 and 5, the refrigerant headers 10 and 11 shown in FIG. 1 are omitted.

  The above-described heat exchanger 1 is particularly effective when used in a heat exchanger of an outdoor unit of an air conditioner as shown in FIG. 3, but is not limited to an outdoor unit. It can also be applied as a heat exchanger. Next, an application example to an indoor unit will be described with reference to FIGS.

FIG. 6 is a schematic sectional side view for explaining an example in which the heat exchanger used in the air conditioner of the present invention is adopted in an indoor unit of a room air conditioner.
In FIG. 6, reference numeral 1 denotes a heat exchanger (indoor heat exchanger) installed in an indoor unit 70 of a room air conditioner. The heat exchanger 1 is configured to enclose a cross-flow fan 61 in order to increase the heat transfer area. It is installed in the case 15. A drain pan portion 15aa for receiving the condensed water condensed in the heat exchanger 1 and an air outlet forming portion 15ab for forming the air outlet 16 are provided on the lower back surface 15a of the case 15. A drain pan portion 15ba and an outlet forming portion 15bb are also provided in the front lower portion 15b of the case. A front panel 15c is provided at the upper front of the case 15. The front panel 15c is configured to be openable and closable, and is configured to open during operation to form the suction port 17. 61 is a blower fan composed of a cross-flow fan. The blower fan 61 sucks room air from the upper and front suction ports 17 as shown by arrows 18 and passes the heat exchanger 1 through the heat exchanger 1. After the heat exchange with the refrigerant flowing in the interior 1, as indicated by an arrow 19, cold air or hot air is blown out into the room from the outlet 16. Reference numeral 71 denotes a wind direction louver provided at the air outlet 16, and the wind direction louver 71 can adjust the blowing direction into the room.

Even in the case of an indoor unit using such a cross-flow fan 61, the wind speed distribution of the air passing through the heat exchanger 1 is generated, and therefore the flat tube 20 disposed in the portion where the wind speed is increased is shown in FIG. A flat tube 20b having a high corrosion resistance specification shown in B) is employed. In addition, chlorine adhering to the upper part of the heat exchanger 1 is caused to flow downward together with condensed water in a portion close to the drain pans 15aa and 15ba, particularly in a portion below the heat exchanger 1 close to the drain pan 15ba. It tends to collect in the lower part of the installed flat tube 20 or fin 30. Therefore, the flat tube 20b having a high corrosion resistance is also used for the flat tube 20 in the lower region. As the flat tube 20 disposed in the other part (region), the flat tube 20a having a specification with relatively low corrosion resistance shown in FIG.
Thereby, generation | occurrence | production of pitting corrosion can be suppressed, the lifetime of the heat exchanger 1 can be lengthened, and the air conditioner which can also reduce manufacturing cost can be obtained.

FIG. 7 is a schematic perspective view illustrating an example in which the heat exchanger used in the air conditioner of the present invention is employed in an indoor unit of a packaged air conditioner.
In the indoor unit 80 of the packaged air conditioner shown in FIG. 7, when the heat exchanger 1 is configured in a rectangular shape, and a turbo fan (blower fan) 62 installed inside the rectangular heat exchanger 1 is rotated, Indoor air is drawn into the turbo fan 62 from below as indicated by an arrow 81, blown in the radial direction of the turbo fan 62, passes through the four sides of the heat exchanger 1, and passes through four sides as indicated by an arrow 82. Blown in the direction.

  In FIG. 7, the casing, drain pan, suction port, air outlet, and the like of the indoor unit 80 are omitted, but the cold air or hot air blown out as indicated by the arrow 82 is in four directions of the indoor unit 80. It is comprised so that it may blow off indoors from the provided blower outlet.

  Even in the case of such an indoor unit 80, since the wind speed distribution of the air passing through the heat exchanger 1 is generated, the corrosion resistance shown in FIG. The flat tube 20b having a high specification is adopted. For example, since the wind speed near the center of each part arranged on the four sides of the heat exchanger 1 tends to be high, the flat tube 20 arranged near the center part in the vertical direction has high corrosion resistance. The flat tube 20b is used.

  Moreover, the chlorine adhering to the upper part of the heat exchanger 1 goes down with condensed water to the flat tube 20 and the fin 30 arrange | positioned in the part near the drain pan which is not shown in figure, ie, the area | region below the heat exchanger 1. Easily collected after being washed away. Therefore, the flat tube 20b having a high corrosion resistance is also used for the flat tube 20 in the lower region.

  The flat tube 20a used in the other part employs a flat tube 20a having a relatively low corrosion resistance as shown in FIG. Thereby, even in the case of an indoor unit of a packaged air conditioner, the occurrence of pitting corrosion can be suppressed, the life of the heat exchanger 1 can be lengthened, and the manufacturing cost can be reduced.

  A second embodiment of the air conditioner of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view showing a flat tube used in the heat exchanger of the second embodiment, and the flat tube 20c shown in FIG. 8A has a specification with relatively low corrosion resistance. For example, the heat described in FIG. It is a flat tube used for a portion having a relatively small amount of chlorine adhesion, such as the flat tube 20 in the region u above the exchanger 1. The flat tube 20d shown in (B) has a high corrosion resistance specification. For example, the flat tube 20d in the region d below the heat exchanger 1 described in FIG. It is a tube.

  The flat tubes 20c and 20d in the second embodiment have the same basic structure and material as the flat tubes 20 (20a and 20b) shown in FIG. That is, in FIG. 8, 21c and 21d are refrigerant flow paths (spaces), 22c and 22d are sacrificial anode layers, and 23c and 23d are aluminum cores.

  The flat tube of the present embodiment is different from the flat tube shown in FIG. 2 in that the thickness H4 of the flat tube 20d having high corrosion resistance is set to be larger than the thickness H3 of the flat tube 20c having relatively low corrosion resistance. It is to make it bigger. Thereby, the aluminum thickness tw4 including the sacrificial anode layer 22d of the flat tube 20d can be configured to be larger than the aluminum thickness tw3 including the sacrificial anode layer 22c of the flat tube 20c (tw4> tw3). . Accordingly, the thickness of the sacrificial anode layer 22d and the aluminum core material 23d can be increased, and the flat tube 20d having specifications with high corrosion resistance can be easily manufactured. In addition, the heights of the refrigerant flow paths 21c and 21d of the flat tubes 20c and 20d can be configured to be equal (hc3 = hc4). Note that te3 and te4 are the thicknesses of the sacrificial anode layers 22c and 22d.

  Thus, also by using the flat tubes 20c and 20d shown in the second embodiment, one aluminum heat exchanger can be configured by two or more types of flat tubes having different corrosion resistance specifications. In FIG. 8, two types of flat tubes having different corrosion resistance specifications are shown, but it is also possible to easily make three or more types of flat tubes having different corrosion resistance specifications.

  Further, the flat tubes 20c and 20d having different corrosion resistance specifications are configured such that both the thickness of the sacrificial anode layers 22c and 22d and the thickness of the aluminum cores 23c and 23d are thicker than those of the flat tube 20c. However, only one of the sacrificial anode layers 22c and 22d and the aluminum core members 23c and 23d may be thicker than that of the flat tube 20c.

As shown in FIG. 8, two or more types of flat tubes having different corrosion resistance specifications are prepared, for example, located in a portion (such as the lower part of the heat exchanger) where a large amount of chlorine adheres and pitting corrosion easily occurs as shown in Table 1 above. The flat tube 20d having high corrosion resistance is used as the flat tube. Moreover, the said flat tube 20c of a specification with comparatively low corrosion resistance is used for the flat tube located in a part with comparatively little adhesion of chlorine. By comprising in this way, while improving the corrosion resistance of the heat exchanger 1 and extending the lifetime, the manufacturing cost can also be reduced. Further, according to the second embodiment, the area of the refrigerant flow passages 21c and 21d can be made the same regardless of which flat tube 20c or 20d is used, and therefore the flat tube 20 installed in any part of the heat exchanger 1 is the same. It becomes possible to flow the refrigerant flow rate.
Other configurations are the same as those in the first embodiment.

Embodiment 3 of the air conditioner of the present invention will be described with reference to FIG. FIG. 9 is a front view showing a heat exchanger used in the air conditioner of the third embodiment.
The heat exchanger used in the third embodiment is provided with refrigerant headers 10 and 11 on the upper and lower sides thereof, and a plurality of flat tubes 20 are respectively installed in the vertical direction so as to connect the refrigerant headers 10 and 11. Yes. Such a heat exchanger 1 has good drainage of condensed water on the surfaces of the fins 30, and the condensed water easily flows downward, so that the condensed water does not easily accumulate between the fins 30. Moreover, since the refrigerant | coolant distribution performance from the refrigerant | coolant headers 10 and 11 is also good, it is a heat exchanger with which high heat exchange performance is obtained.

  Even in this type of heat exchanger 1, the amount of chlorine adhering to the region d in the lower part of the heat exchanger 1 increases as in the first embodiment. For this reason, the lower portion of each flat tube 20 is more easily corroded than the upper portion thereof.

  Therefore, in the case of the third embodiment, zinc is applied thickly by dipping or the like on the surface of the lower portion of each flat tube 20 corresponding to the lower region d of the heat exchanger 1, and at the time of subsequent brazing The zinc applied by heating is diffused to form a sacrificial anode layer. By comprising in this way, since the corrosion resistance of the lower part of each flat tube 20 can be made higher than the upper part, the corrosion resistance of the heat exchanger 1 can be improved and the lifetime can be extended. Moreover, since it is only the lower part of the flat tube 20 that increases the application quantity of zinc, manufacturing cost can also be reduced.

Thus, the present invention can also be applied to the heat exchanger 1 in which the refrigerant headers 10 and 11 are provided on the upper and lower sides and the flat tube 20 is installed in the vertical direction.
Other configurations are the same as those in the first embodiment.

  Embodiment 4 of the air conditioner of the present invention will be described with reference to FIGS. FIG. 10 is a perspective view showing a heat exchanger used in the fourth embodiment, and FIG. 11 is a cross-sectional view illustrating the configuration of the upper flat tube 20e and the lower flat tube 20f shown in FIG.

The fourth embodiment is a more preferable example when the present invention is applied to an L-shaped heat exchanger 1 used in an outdoor unit such as a room air conditioner as shown in FIG.
As in the first embodiment, the flat tube 20f having a high corrosion resistance specification shown in FIG. 11B is used for the lower flat tube 20 where the amount of adhesion of chlorine is larger, and the amount of adhesion of chlorine is relatively high. The lower flat tube 20 that is reduced is provided with a flat tube 20e having a relatively low corrosion resistance as shown in FIG.

  That is, as in Example 1 shown in FIG. 2, the aluminum thickness tw2 including the sacrificial anode layer 22f of the flat tube 20f disposed in the lower region is equal to the flat tube 20e disposed in the upper region. The sacrificial anode layer 22e is made thicker than the aluminum thickness tw1. Also, the height of the refrigerant flow path of the refrigerant pipe 21e of the flat tube 20e is higher than that of the refrigerant flow path 21f of the flat pipe 20f. The sacrificial anode layers 22e and 22f are configured such that the thickness of the flat tube 20f disposed in the lower region is greater than the thickness of the flat tube 20e disposed in the upper region. .

As described above, the configuration of the flat tubes 20e and 20f in the thickness direction is the same as that in the first embodiment. The fourth embodiment differs from the first embodiment in the thickness of the aluminum cores 23e and 23f in the width direction of the flat tube. In the L-shaped heat exchanger 1 of the outdoor unit, the thickness of the outer peripheral portion of the arc portion bent into the L-shape is reduced due to the elongation during bending. When the wall thickness is thin, the corrosion life against pitting corrosion is shortened. Therefore, in this embodiment, both the flat tubes 20e and 20f are configured such that the outer wall thicknesses tw5 and tw7 are thicker than the inner wall thicknesses tw6 and tw8. By setting it as such a structure, corrosion resistance can be improved also in the heat exchanger 1 bent in the L-shape.
Other configurations are the same as those in the first embodiment.

  Embodiment 5 of the air conditioner of the present invention will be described with reference to FIG. FIG. 12: is a front view which shows the heat exchanger used for Example 5 of the air conditioner of this invention.

  The fifth embodiment relates to a more preferable application form of the flat tubes 20a and 20b shown in FIG. 2 of the first embodiment. The heat exchanger 1 shown in FIG. 1 in the first embodiment is a heat exchanger in which a refrigerant flows from one refrigerant header 10 to the other refrigerant header 11. On the other hand, the heat exchanger 1 of the fifth embodiment is a heat exchanger 1 in which the refrigerant flows from the one refrigerant header 10 to the other refrigerant header 11 by a length of one reciprocal half. A preferred example of applying the present invention to this heat exchanger will be described.

  The case where the heat exchanger 1 shown in FIG. 12 is an outdoor heat exchanger installed in an outdoor unit of an air conditioner will be described. In such a heat exchanger, the refrigerant condenses during cooling operation of the air conditioner. That is, the high-temperature and high-pressure gas refrigerant from the compressor flows into the refrigerant header (gas header) 10, and then flows through the flat tube 20 in the region u shown in FIG. 12 and into the intermediate header 100 provided on the opposite side. . After flowing downward in the intermediate header 100, it flows through the flat tube 20 in the area m and flows into the intermediate header 101 on the opposite side. From this intermediate header 101, it passes through the flat tube 20 in the area d, reaches the refrigerant header (liquid header) 11, and flows out of the heat exchanger 1.

  The gas refrigerant that has flowed into the heat exchanger 1 exchanges heat with outdoor air while passing through the flat tube 20 in the u region and the flat tube 20 in the m region, and the refrigerant is saturated. A phase state is reached, and the ratio of the refrigerant liquid gradually increases. The refrigerant passing through the flat tube 20 in the region d flows in a liquid single-phase flow state.

  Therefore, in the fifth embodiment, the flattened tube 20 shown in FIG. 2A is used for the flat tube 20 in a portion (region u or the like) in which the refrigerant gas or a gas-liquid two-phase refrigerant with a high proportion of the refrigerant gas flows. Tube 20a is used. Further, a flat tube 20b shown in FIG. 2 (B) is used for a flat tube 20 in a portion (region d or the like) where a refrigerant in a liquid single-phase flow state or a gas-liquid two-phase state with a large amount of refrigerant liquid flows. To do. In addition, three types of flat tubes having different corrosion resistance specifications may be prepared, and an intermediate corrosion resistance specification flat tube may be used in the region m.

  By configuring in this way, the flat tube 20b having a small refrigerant channel cross-sectional area is disposed in the portion where the single-phase flow of the liquid refrigerant flows, so that the flow rate of the liquid refrigerant flowing through the flat tube 20b is increased. Can do. Although the heat transfer coefficient of the liquid refrigerant single-phase flow is relatively small, the single-phase flow heat transfer coefficient can be increased by increasing the flow velocity.

  When heating operation is performed, the refrigerant evaporates in the outdoor heat exchanger. During this heating operation, the gas-liquid two-phase refrigerant flows into the refrigerant header 11 and then flows through the flat tube 20b installed in the region d. Although the refrigerant channel cross-sectional area of the flat tube 20b is small, the degree of dryness of the refrigerant flowing therethrough is small and the ratio of liquid refrigerant is large, so that an increase in pressure loss can be suppressed. Next, when the refrigerant passes through the intermediate header 101, the flat tube installed in the region m, and the ratio of the gas refrigerant gradually increases while passing through the intermediate header 100, the refrigerant passes through the flat tube 20a installed in the region u. It becomes a gas refrigerant. However, since the refrigerant channel cross-sectional area of the flat tube 20a is large, an increase in pressure loss can be suppressed even in this portion. Thereafter, the gas refrigerant is sucked into the compressor from the refrigerant header 10 through the refrigerant gas pipe.

  As described above, in the fifth embodiment, the flat tube 20b having a small refrigerant channel cross-sectional area but high corrosion resistance is disposed in the region d below the heat exchanger 1, and the region u above the heat exchanger 1 is arranged. In the same manner as in the first embodiment, by arranging the flat tube 20a having a relatively low corrosion resistance but a large refrigerant channel cross-sectional area, it is possible to improve the corrosion resistance of the heat exchanger 1 and extend its life. And manufacturing costs can be reduced. Further, in the fifth embodiment, since the flat tube 20b having a small refrigerant flow cross-sectional area is disposed in the portion where the single-phase flow of the liquid refrigerant flows, heat flow is increased by increasing the flow velocity of the single-phase flow of the liquid refrigerant. The effect which can improve a rate is also acquired.

According to each embodiment of the present invention described above, not all the portions constituting the heat exchanger are constituted by flat tubes having high corrosion resistance specifications, but the amount of chlorine attached to the heat exchanger of the air conditioner, The flat tube in the large accumulation area has a high corrosion resistance specification, so it is possible to improve the reliability by suppressing the occurrence of pitting corrosion, extending the life of the heat exchanger, and reducing the cost rise. Can be obtained.
Thus, according to the present embodiment, there is an effect that an air conditioner that can improve the corrosion resistance of the heat exchanger to extend its life and can also reduce the manufacturing cost of the heat exchanger can be obtained.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, in the above-described embodiment, the heat exchanger is configured by a plurality of flat tubes made of aluminum. However, the heat exchanger is not limited to the one formed by the flat tubes, and is a circular tube made of aluminum. Even if it exists, it can apply similarly.

  Further, the above-described embodiments have been described in detail for easy understanding in the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

1: heat exchanger, 10, 11: refrigerant header, 12: refrigerant gas pipe, 13: refrigerant liquid pipe,
15: Case (15a: rear portion, 15b: lower front portion, 15c: front panel),
16: Air outlet, 17: Air inlet,
20, 20a, 20b, 20c, 20e, 20f: flat tube,
21a, 21b, 21c, 21d, 21e, 21f: refrigerant flow path (space),
22a, 22b, 22c, 22d, 22e, 22f: sacrificial anode layers 23a, 23b, 23c, 23d, 23e, 23f: aluminum cores,
30: fin (strip-shaped fin), 30a: slit part, 30b: uneven part,
31: Fin (corrugated fin), 31a: Fine slit,
40: outdoor unit, 50: compressor 60-62: blower fan (60: propeller fan, 61: cross-flow fan, 62: turbo fan),
70: indoor unit for room air conditioner, 71: wind direction louver,
80: indoor unit for packaged air conditioner,
100, 101: Intermediate header.

Claims (10)

An air conditioner comprising a heat exchanger composed of a plurality of aluminum tubes,
Of the plurality of tubes constituting the heat exchanger, the tube disposed below the gravitational direction is composed of a tube having specifications with higher corrosion resistance than the tube disposed above. Harmony machine. An air conditioner comprising a heat exchanger composed of a plurality of aluminum tubes,
Among the plurality of pipes constituting the heat exchanger, the pipe disposed at a place where the wind speed is high is constituted by a pipe having a specification having higher corrosion resistance than a pipe placed at a place where the wind speed is low. Air conditioner. An air conditioner comprising a heat exchanger composed of a plurality of aluminum tubes,
The plurality of tubes constituting the heat exchanger are installed so as to be directed in the direction of gravity, and the lower portion of the tubes is configured to have higher corrosion resistance than the upper portion. A featured air conditioner. The air conditioner according to claim 1 or 2,
The aluminum tube is a flat aluminum tube,
The air conditioner is characterized in that the pipe (flat tube) having a specification with high corrosion resistance is provided with a sacrificial anode layer having a thickness larger than that of the other pipe (flat tube). The air conditioner according to claim 4,
The air conditioner characterized in that the sacrificial anode layer is composed of a zinc sprayed diffusion layer or an aluminum clad layer. The air conditioner according to claim 1 or 2,
The aluminum tube is a flat aluminum tube,
The air conditioner characterized in that the pipe (flat pipe) having a high corrosion resistance is constituted by a flat pipe having a larger wall thickness than other pipes (flat pipe). The air conditioner according to claim 3,
The aluminum tube is a flat aluminum tube,
An air conditioner characterized in that a sacrificial anode layer having a larger thickness is provided in a lower part of the flat tube than in an upper part thereof. The air conditioner according to any one of claims 1 to 3,
The aluminum tube is a flat aluminum tube,
The heat exchanger is configured by integrally forming the flat tube, aluminum fins installed between the flat tubes, and refrigerant headers provided on both sides of the flat tube by brazing. Air that flows between the fins, supplies the refrigerant to the refrigerant header, and causes the refrigerant to flow through the flow path in the flat tube, thereby exchanging heat between the air and the refrigerant. Harmony machine. The air conditioner according to claim 1 or 2,
The aluminum tube is a flat aluminum tube,
This flat tube is configured in an L-shaped shape, and the outer peripheral side of the bent arc portion of the flat tube is configured such that the thickness of the flat tube is larger than the inner peripheral side. An air conditioner characterized by that. The air conditioner according to claim 1 or 2,
The aluminum tube is a flat aluminum tube,
When the refrigerant in the heat exchanger condenses, the refrigerant channel cross-sectional area of the flat tube through which the single-phase flow portion that becomes the condensate flows is smaller than the refrigerant channel cross-sectional area of the flat tube through which the refrigerant gas flows. An air conditioner characterized by having a small structure.

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