JP2010197008A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of suppressing pressure loss and unifying a ratio of a gas component and a liquid component in a second block. <P>SOLUTION: The first block is composed of a first tank T1 having a refrigerant inlet into which a refrigerant flows, a plurality of first tubes 21 in which the refrigerant flowing into the first tank T1 is distributed and flows, and a second tank T2 in which the refrigerants flowing in the first tubes 21 join. A second block is composed of a third tank T3 into which the refrigerant joining at the second tank T2 flows, a plurality of second tubes 22 to which the refrigerant flowing into the third tank T3 is distributed and flows, and a forth tank T4 in which the refrigerants flowing in the second tubes 22 join, and which has a refrigerant outlet from which the joined refrigerants flow. In this heat exchanger 10, a refrigerant passage 43h in which the refrigerant flows from the second tank T2 to the third tank T3 is disposed in a state of being deflected to a side opposite to the refrigerant inlet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat exchanger, and more particularly to a heat exchanger suitably used for an evaporator of an in-vehicle air conditioning refrigeration cycle mounted on an automobile.

  The heat exchanger constituting the evaporator (or condenser) used in the refrigeration cycle includes a core in which a plurality of tubes and a plurality of fins are alternately stacked, and a tank to which the ends of the tubes are connected. What is known. The refrigerant is taken into the inside from an inlet header provided in the tank, passes through the tube while exchanging heat with air by heat transmitted to the core, and then discharged to the outside from the outlet header provided in the tank.

As will be described below, an evaporator mounted on an automobile is required to be small and light as well as high performance.
Generally, the performance Q of the evaporator is expressed by Q = K · A · (Ta−Tr). Here, K is the heat transfer rate, A is the heat transfer area, Ta is the air temperature, and Tr is the refrigerant temperature. Since the refrigerant temperature Tr decreases as the refrigerant pressure loss in the evaporator decreases, it is important to keep the refrigerant pressure loss low in the evaporator in order to improve the evaporator performance Q (increase (Ta-Tr)). It is.
Further, normally, the refrigerant circulation amount Gr [kg / s] flowing in the refrigeration cycle during operation is the same through the refrigerant flow path, and the inside of the evaporator is also the same. In the evaporator, the refrigerant gradually evaporates while exchanging heat with air. However, since the refrigerant gasifies and the density of the refrigerant decreases and the flow velocity increases, the refrigerant pressure loss is relatively large on the outlet side. Become.
From the above, in order to improve the evaporator performance Q, it is required to reduce the pressure loss of the refrigerant, in particular, to reduce the pressure loss of the refrigerant toward the outlet side.

On the other hand, an evaporator generally used in an automobile has a multi-flow structure in which refrigerant is distributed from a single tank to a plurality of tubes. Therefore, uniform refrigerant distribution (particularly liquid components that affect cooling performance) is also required. . If the refrigerant distribution is non-uniform, the heat transfer area A in the portion with a small liquid component becomes small (cannot be used effectively), leading to a decrease in performance Q.
At present, when the width of the evaporator is reduced due to the demand for downsizing on an automobile, the refrigerant passage inside the evaporator is reduced, so that the pressure loss of the refrigerant increases and the evaporator performance deteriorates. Then, the evaporator which reduced the refrigerant | coolant circuit division | segmentation number in an evaporator and reduced the pressure loss of a refrigerant | coolant is proposed (patent document 1).

  FIG. 9 shows a heat exchanger 100 disclosed in Patent Document 1. In the heat exchanger 100, two or more rows of tube groups 105 each including a plurality of heat exchange tubes (hereinafter referred to as tubes) 104 are provided between the refrigerant inlet / outlet side tank 102 and the refrigerant turn side tank 103. The refrigerant inlet header chamber 106 of the refrigerant inlet / outlet tank 102 is partitioned into two spaces 106 a and 106 b in the height direction by a resistance plate 107 for diversion. The tube 104 is connected to the refrigerant inlet / outlet tank 102 so as to face the first space 106a. One coolant passage hole 108 is formed in the central portion in the length direction of the shunt resistor plate 107. The refrigerant that has flowed into the first space 106 a of the refrigerant inlet header chamber 106 of the refrigerant inlet / outlet tank 102 passes through the refrigerant passage hole 108 and enters the second space 106 b, passes through the tube 104, and enters the refrigerant turn side tank 103. The refrigerant flows into the refrigerant outlet header chamber 109 of the refrigerant inlet / outlet side tank 102 through the tube 104 while changing the flow direction.

  According to the heat exchanger 100 of Patent Document 1, the refrigerant is fed into the second space 106 b in the refrigerant inlet header chamber 106 of the refrigerant inlet / outlet tank 102 and passes through one refrigerant passage hole 108 of the shunting resistance plate 107. Then, the air flows into the first space 106a and is divided into all the tubes 104 communicating with the refrigerant inlet header chamber 106 from the first space 106a. Since only one refrigerant passage hole 108 is formed in the shunting resistance plate 107, the refrigerant gently flows into the first space 106a from the second space 106b, and the first space 106a. It flows in all the tubes 104 throughout. Accordingly, the ratio of the gas component and the liquid component of the refrigerant in the heat exchange pipe connected to the refrigerant inlet header chamber of the refrigerant inlet / outlet tank, that is, the refrigerant distribution is made uniform, and the heat exchange performance of the heat exchanger is improved.

Japanese Patent Laid-Open No. 2005-43040

However, in the heat exchanger 100, the refrigerant circuit is composed of two blocks (the refrigerant inlet side is the first block and the outlet side is the second block), and the refrigerant is equally distributed to all tubes in both the first block and the second block. Therefore, the ratio of the gas component and the liquid component in each tube tends to be non-uniform. This tendency becomes more conspicuous especially in the second block on the outlet side where the evaporation of the refrigerant proceeds and the ratio of the gas component increases. Therefore, in Patent Document 1, a shunting auxiliary resistance plate 110 that partitions the refrigerant outlet header chamber 109 up and down is provided.
In Patent Document 1, although the refrigerant circuit is composed of two blocks in order to reduce pressure loss, an auxiliary resistor for shunting is provided in the refrigerant outlet header chamber 109 in which the refrigerant is almost gasified for uniform refrigerant distribution. The structure in which the plate 110 is provided results in an increase in pressure loss. From the viewpoint of improving the performance Q, the effect of reducing the pressure loss is not sufficient.
The present invention has been made based on such a technical problem, and an object of the present invention is to provide a heat exchanger in which pressure loss is suppressed and refrigerant distribution in the second block can be made uniform.

In the heat exchanger according to the present invention, the refrigerant passes through the first block and the second block in order and flows out from the second block.
In the heat exchanger according to the present invention, the first block includes a first tank provided with a refrigerant inlet into which refrigerant flows, a plurality of first tubes in which the refrigerant flowing into the first tank flows in a distributed manner, and the first tubes And a second tank into which the refrigerant flowing through joins. In the heat exchanger according to the present invention, the second block includes a third tank into which the refrigerant merged in the second tank flows, a plurality of second tubes in which the refrigerant flowing into the third tank flows in a distributed manner, A refrigerant outlet flowing through the tube merges, and a refrigerant outlet through which the merged refrigerant flows out is provided and includes a fourth tank.
The heat exchanger according to the present invention is characterized in that the refrigerant passage through which the refrigerant flows from the second tank to the third tank is provided so as to be biased to the opposite side to the refrigerant inlet.
In the heat exchanger according to the present invention, the non-uniformity of the refrigerant distribution generated in the first block is opposite to the refrigerant inlet through the refrigerant passage from the second tank to the third tank, that is, the refrigerant flow from the first block to the second block. It is eliminated in the second block by providing it on the side (hereinafter referred to as the opposite entrance side). Thus, the refrigerant distribution in the second block is made uniform without providing special resistance means in the fourth tank (corresponding to the refrigerant outlet header chamber 109 of Patent Document 1) in which the refrigerant is almost gasified, and the heat exchanger The heat exchange performance is improved.

In the heat exchanger according to the present invention, the first block and the second block are arranged in parallel to each other, the first tank and the fourth tank are on the upper side in the vertical direction, and the second tank and the third tank are on the lower side in the vertical direction. It is preferable to arrange | position.
According to this heat exchanger, the refrigerant is guided vertically downward from the first tank to the second tank, and the refrigerant is guided vertically upward from the third tank to the fourth tank. In this way, the refrigerant flows from the lower second tank toward the third tank toward the inlet side from the counter-inlet side, thereby facilitating the flow of the liquid component to the inlet side of the third tank. The distribution of the gas component and the liquid component in the second tube) is made uniform.

  In the heat exchanger according to the present invention, the refrigerant passage through which the refrigerant flows from the second tank to the third tank is configured by providing a plurality of holes in the partition provided between the second tank and the third tank. Is preferred. Mixing of the gas component and the liquid component is promoted, and the uniformity of refrigerant distribution in the second block (second tube) can be improved.

In the heat exchanger of the present invention, it is preferable that a resistor for the refrigerant is provided in the third tank and behind the refrigerant passage in the flow direction of the refrigerant. The distribution amount of the refrigerant, particularly the liquid component, flowing in the third tank to the inlet side is made uniform in the third tank. Since the liquid component is in the middle of evaporation in the third tank, pressure loss can be suppressed even if there is a resistor.
When a plurality of resistors are provided, it is preferable that the aperture ratio of the second and subsequent resistors provided behind the refrigerant flow direction is equal to or less than the aperture ratio of the upstream resistor. This is because gradually reducing the liquid component amount toward the refrigerant inlet side is preferable for improving the distribution uniformity of the gas component and the liquid component.

  In the heat exchanger of the present invention, the refrigerant flow passage areas in the third tank and the fourth tank constituting the second block are set to be larger than the refrigerant flow passage areas in the first tank and the second tank constituting the first block. It is preferable to enlarge it. Without changing the external size of the heat exchanger, it is possible to reduce the pressure loss in the second block having a larger proportion of the gas component. For the same purpose, it is preferable to make the refrigerant passage area of the second tube constituting the second block larger than the refrigerant passage area of the first tube constituting the first block.

  According to the present invention, the non-uniformity of the refrigerant distribution that occurs in the first block is caused by biasing the refrigerant passage from the second tank to the third tank, that is, the refrigerant passage through which the refrigerant flows from the first block to the second block, toward the opposite inlet side. By providing it, the refrigerant distribution in the second block can be made uniform and heat exchange even without providing special resistance means in the fourth tank (corresponding to the refrigerant outlet header chamber 109 of Patent Document 1) in which the refrigerant is almost gasified. The heat exchange performance of the vessel is improved.

It is a perspective view which shows the heat exchanger concerning this embodiment. It is a disassembled perspective view which shows the heat exchanger concerning this embodiment. It is the front view of the heat exchanger concerning this embodiment, its AA arrow sectional drawing, BB arrow sectional drawing, and CC arrow sectional drawing. It is a figure which shows the refrigerant | coolant flow path of the heat exchanger concerning this embodiment. A mode that a refrigerant (liquid component) flows through a heat exchanger concerning this embodiment is shown typically, (a) shows the 1st block and (b) shows the 2nd block. The mode that a refrigerant (liquid component) flows through the other heat exchanger concerning the present invention is shown typically, (a) shows the 1st block and (b) shows the 2nd block. A mode that a refrigerant (liquid component) flows through the heat exchanger of a comparative example is typically shown, (a) shows the 1st block and (b) shows the 2nd block. It is sectional drawing of the tank of the heat exchanger concerning this Embodiment. It is a perspective view which shows the heat exchanger disclosed by patent document 1. FIG.

Hereinafter, the present invention will be described in detail based on embodiments. In addition, the heat exchanger 10 concerning this embodiment is used suitably for the evaporator of the refrigerating cycle for vehicle interior air conditioning mounted in a motor vehicle.
<Overall configuration of heat exchanger 10>
As shown in FIGS. 1 to 4, the heat exchanger 10 includes a core 20 formed by alternately laminating a plurality of first tubes 21, second tubes 22, and a plurality of fins 23 through which a refrigerant flows, and a first tube. 21, an upper tank 30 to which one end (the upper end in the figure) side of the second tube 22 is connected, and a lower tank 40 to which the other end (the lower end in the figure) side of the first tube 21 and the second tube 22 is connected, The heat exchange of the refrigerant is performed by the heat transmitted to the core 20.

<Configuration of core 20>
The 1st tube 21 and the 2nd tube 22 consist of copper or a copper alloy, or aluminum or an aluminum alloy, and are the members of the rectangular cross section which has the hollow part produced by roll-molding extrusion molding or a plate-shaped raw material. In the heat exchanger 10, the first tube 21 and the second tube 22 are arranged in two rows in the width direction (Y direction in FIG. 2). The upper ends of the first tube 21 and the second tube 22 are connected to the upper tank 30, and the lower ends of the first tube 21 and the second tube 22 are connected to the lower tank 40. The inside of the second tube 22 and the inside of the lower tank 40 are communicated so that the refrigerant can flow. This connection is usually made by brazing. In addition, the cross-sectional shape of the 1st tube 21 and the 2nd tube 22 is not restricted to a rectangle, A circle and other shapes may be sufficient.
The fins 23 are made of the same material as the first tube 21 and the second tube 22, and in the present embodiment, corrugated fins formed by roll molding or the like are used. Fins can be used.
The core 20 includes the first tube 21, the second tube 22, and the fins 23 that are alternately stacked in the longitudinal direction of the heat exchanger 10 (the X direction in FIG. 2). It is sealed with. The side plate 24 functions as a reinforcing member for the core 20, and both end portions in the longitudinal direction are supported by the upper tank 30 and the lower tank 40.

<Configuration of upper tank 30>
The upper tank 30 has a tank plate 31 and an end plate 32 as main components, and is assembled with the openings facing each other. An upper partition plate 33 is provided in the upper tank 30 along the longitudinal direction. The upper partition plate 33 partitions the inside of the upper tank 30 at the center in the width direction. One of the partitioned sides constitutes the first tank T1, and the other side constitutes the fourth tank T4. The first tube 21 is connected to the lower surface of the first tank T1, and the second tube 22 is connected to the lower surface of the fourth tank T4. Since the upper partition plate 33 is provided between the first tank T1 and the fourth tank T4, there is no direct movement of the refrigerant between them.

A cap 34 is provided on one end side in the longitudinal direction of the upper tank 30. The cap 34, the refrigerant inflow hole _{h in} the refrigerant outlet hole _{h ex} is formed. A cap 35 is provided on the other end side in the longitudinal direction of the upper tank 30. The cap 35 seals the other end side of the upper tank 30 in the longitudinal direction.

<Configuration of lower tank 40>
The lower tank 40 includes a tank plate 41 and an end plate 42 as main components, and is assembled with the openings facing each other. A lower partition plate 43 is provided in the lower tank 40 along the longitudinal direction. The lower partition plate 43 partitions the inside of the lower tank 40 at the center in the width direction. One of the partitioned sides constitutes the second tank T2, and the other side constitutes the third tank T3. The first tube 21 is connected to the upper surface of the second tank T2, and the second tube 22 is connected to the upper surface of the third tank T3.

The lower partition plate 43 is provided with a refrigerant passage 43h penetrating in the plate thickness direction. A plurality (seven in this example) of refrigerant passages 43 h are provided so as to be biased toward one end in the longitudinal direction of the lower partition plate 43. Here, in the longitudinal direction of the heat exchanger 10, located on the opposite side to the refrigerant inflow hole h _in a refrigerant inlet.
In the lower tank 40, a lower partition plate 43 is provided between the second tank T2 and the third tank T3, but a plurality of refrigerants are arranged so as to be biased to the side opposite to the refrigerant inlet (hereinafter referred to as the opposite inlet side). The refrigerant flows from the second tank T2 into the third tank T3 through the passage 43h. The refrigerant passage 43 h is preferably provided in a range of 20% or less of the entire length of the lower partition plate 43. Increasing the flow rate of the refrigerant passing through the refrigerant passage 43h is effective for uniformly mixing the gas component and the liquid component of the refrigerant. The refrigerant passage 43h is composed of a plurality of circular holes, but may be a wide refrigerant passage having a long diameter in the longitudinal direction of the lower partition plate 43. However, in order to uniformly mix the gas component and the liquid component, it is preferable to provide a plurality of small-diameter refrigerant passages 43h as in the present embodiment.

The lower tank 40 is provided with distribution adjusting plates 46, 47, and 48 in the third tank T3. The distribution adjusting plates 46, 47, 48 are arranged at a predetermined interval in this order from the opposite entrance side. The distribution adjusting plates 46, 47, and 48 have through holes 46h, 47h, and 48h through which the refrigerant passes, respectively. The refrigerant that has flowed into the third tank T3 through the refrigerant passage 43h sequentially passes through the through holes 46h, 47h, and 48h and flows downstream, while the distribution adjusting plates 46, 47, and 48 serve as resistors. Here, in the third tank T3, when there is no distribution adjustment plate 46, 47, 48, the liquid component in the refrigerant tends to flow downstream, and the gas component tends to stay upstream. Thus, if the liquid component is biased in the longitudinal direction and the refrigerant distribution becomes non-uniform, sufficient evaporation performance cannot be obtained. Therefore, by using the distribution adjustment plates 46, 47, and 48 as the liquid component resistors, the liquid component and the gas component in the refrigerant are distributed as evenly as possible from the upstream to the downstream of the third tank T3. .
Since the distribution adjusting plates 46, 47 and 48 are resistors, pressure loss is caused in the refrigerant. However, since most of the liquid is provided in the third tank T3 during evaporation, the pressure loss is minimized. Can do. In the present embodiment, the three distribution adjustment plates 46, 47, and 48 are provided.

The distribution adjustment plate 46 (first distribution adjustment plate from the upstream end) provided for the above purpose is preferably provided at a position relatively close to the upstream end of the third tank T3. As a specific index, a range of 30% or less of the total length of the lower partition plate 43 from the upstream end is set.
The opening ratio of the through holes 46h, 47h, 48h provided in the distribution adjusting plates 46, 47, 48 is preferably in the range of 15-30%. Without increasing the pressure loss of the refrigerant more than necessary, the liquid component and the gas component can be evenly distributed from upstream to downstream. The aperture ratio here refers to the ratio of the through holes 46h, 47h, 48h to the area (transverse section) of the refrigerant flow path in the third tank T3.
When a plurality of distribution adjustment plates 46, 47, 48 are provided, the aperture ratios of the through holes 47h, 48h of the second and subsequent distribution adjustment plates 47, 48 from the upstream end are equal to the adjacent upstream through holes 47h, It is preferable to make it 48 hours or less. This is because the liquid component that tends to flow downstream is retained on the upstream side by narrowing the aperture ratio as it goes downstream.

  A cap 44 is provided on one end side in the longitudinal direction of the lower tank 40. The cap 44 seals one end side in the longitudinal direction of the lower tank 40. A cap 45 is provided on the other end side in the longitudinal direction of the lower tank 40. The cap 45 seals the other end side of the lower tank 40 in the longitudinal direction.

<Flow of refrigerant>
The flow of the refrigerant in the heat exchanger 10 configured as described above will be described. The heat exchanger 10 has a refrigerant flow path composed of a first block and a second block, and the refrigerant flows through the heat exchanger 10 in the order of the first block and the second block. The first block includes a first tank T1, a first tube 21, and a second tank T2, and the second block includes a third tank T3, a second tube 22, and a fourth tank T4.

When the heat exchanger 10 is used as an evaporator of a refrigeration cycle, the refrigerant that has been made into a gas-liquid two-phase with an expansion valve located upstream with respect to the heat exchanger 10 is a refrigerant inlet hole h _in (refrigerant inlet). And flows into the first tank T1.
The refrigerant flowing into the first tank T1 flows vertically downward in the first tube 21 and reaches the second tank T2. In the process of flowing through the first tube 21, the refrigerant exchanges heat with the air passing through the core 20 while the liquid component evaporates.
Here, the refrigerant flowing vertically downward through the first tube 21 varies in the ratio of the gas component and the liquid component in the longitudinal direction of the heat exchanger 10. This is schematically shown in FIG. 7 (a). In the figure, the ratio of the liquid component in the refrigerant is indicated by an arrow, but the ratio of the liquid component flowing toward the first tube 21 closer to the refrigerant inlet becomes higher. Since the liquid component has a greater resistance to the inner wall of the first tank T1 than the gas component, the liquid component is less likely to flow away from the refrigerant inlet.

The refrigerant that has entered the second tank T2 enters the third tank T3 through the refrigerant passage 43h. Since the refrigerant passage 43h is provided so as to be biased toward the opposite inlet side of the lower partition plate 43, the refrigerant that has flowed through the first tube 21 at a position close to the opposite inlet side in the first tube 21 has priority. The third tank T3 is entered through 43h. The refrigerant that has entered the third tank T3 flows vertically upward in the second tube 22 and reaches the fourth tank T4. In the process of flowing through the second tube 22, the refrigerant exchanges heat with the air passing through the core 20 while the liquid component evaporates. The refrigerant in which the liquid component is evaporated in the process of passing through the heat exchanger 10 passes through the fourth tank T4 and is discharged from the refrigerant outflow hole _hex toward the compressor located on the downstream side.

  If the refrigerant passage 43h is formed over the entire area of the second tank T2 (third tank T3) in the longitudinal direction, the ratio of the liquid component of the refrigerant flowing vertically upward through the second tube 22 (second block). Since the state of the 1st tube 21 (1st block) is taken over, as shown in FIG.7 (b), the ratio of a liquid component becomes high as the 2nd tube 22 near the refrigerant | coolant inlet_port | entrance. This state is shown by a one-dot chain line in FIG.

  In contrast to this, the heat exchanger 10 is provided with the refrigerant passage 43h biased toward the counter-inlet side of the lower partition plate 43, and therefore flows through the first tube 21 at a position close to the counter-inlet side in the first tube 21. The refrigerant thus preferentially enters the third tank T3 through the refrigerant passage 43h. As a result, in the second block, as shown by the solid line in FIG. 5B, the non-uniform distribution of the gas component and the liquid component in the longitudinal direction generated in the first block (FIG. 5A, FIG. a)) is eliminated. In addition, the dashed-dotted line of FIG.5 (b) has shown the ratio of the liquid component in case the refrigerant path 43h is formed over the whole longitudinal direction of 3rd tank T3.

  In the above embodiment, the example in which the refrigerant inlet and the refrigerant outlet are provided on the same side of the upper tank 30 has been described. However, as shown in FIGS. 6A and 6B, the refrigerant outlet is opposite to the refrigerant inlet. The same applies to the heat exchanger provided on the side.

Although the embodiments of the present invention have been described above, the configurations described in the above embodiments can be selected or changed to other configurations as appropriate without departing from the spirit of the present invention. It is.
For example, as shown in FIGS. 8A and 8B, the refrigerant passage area of the fourth tank T4 (third tank T3) is larger than the refrigerant passage area of the first tank T1 (second tank T2). The positions and shapes of the upper partition plate 33 and the lower partition plate 43 can be adjusted so as to increase. By doing so, the pressure loss in the 3rd tank T3 and the 4th tank T4 with a larger ratio of a gas component can be reduced, without changing the external size of the heat exchanger 10. Further, as shown in FIG. 8C, the width (refrigerant flow area) of the second tube 22 constituting the second block is larger than the width (refrigerant flow area) of the first tube 21 constituting the first block. ) Can be increased. By doing so, the pressure loss of the refrigerant | coolant in the 2nd block with a larger ratio of a gas component can be reduced, without changing the external size of the heat exchanger 10.

DESCRIPTION OF SYMBOLS 10 ... Heat exchanger 20 ... Core, 21 ... 1st tube, 22 ... 2nd tube, 23 ... Fin 30 ... Upper tank, 33 ... Upper partition plate 40 ... Lower tank, 43 ... Lower partition plate, 43h ... Refrigerant passage,
46, 47, 48 ... distribution adjusting plate, 46h, 47h, 48h ... through hole T1 ... first tank, T2 ... second tank, T3 ... third tank, T4 ... fourth tank

Claims (7)

A heat exchanger in which the refrigerant passes through the first block and the second block in order and flows out of the second block,
The first block includes a first tank provided with a refrigerant inlet through which the refrigerant flows, a plurality of first tubes through which the refrigerant flowing into the first tank is distributed and flows through the first tube A second tank into which the refrigerant merges,
The second block flows through a third tank into which the refrigerant merged in the second tank flows, a plurality of second tubes through which the refrigerant flowing into the third tank flows in a distributed manner, and the second tube. A refrigerant outlet through which the refrigerant merges and the merged refrigerant flows out is provided with a fourth tank;
The heat exchanger, wherein a refrigerant passage through which the refrigerant flows from the second tank to the third tank is provided to be opposite to the refrigerant inlet. The first block and the second block are arranged in parallel;
The heat exchanger according to claim 1, wherein the first tank and the fourth tank are disposed on an upper side in the vertical direction, and the second tank and the third tank are disposed on a lower side in the vertical direction. The refrigerant passage through which the refrigerant flows from the second tank to the third tank;
The heat exchanger according to claim 1 or 2, comprising a plurality of holes in a partition provided between the second tank and the third tank.   The heat exchanger according to any one of claims 1 to 3, wherein a resistor for the refrigerant is provided in the third tank and behind the refrigerant passage in the flow direction of the refrigerant.   5. The heat according to claim 4, wherein a plurality of the resistors are provided, and an aperture ratio in the second and subsequent resistors provided rearward in the flow direction of the refrigerant is equal to or less than an aperture ratio of the upstream resistor. Exchanger.   The refrigerant flow passage area in the third tank and the fourth tank constituting the second block is larger than the refrigerant flow passage area in the first tank and the second tank constituting the first block. The heat exchanger in any one of -5.   The heat exchange according to any one of claims 1 to 6, wherein a refrigerant passage area of the second tube constituting the second block is larger than a refrigerant passage area of the first tube constituting the first block. vessel.

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