JP7105641B2 - Microchannel heat exchanger and refrigeration cycle equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a microchannel heat exchanger having fine flow paths and a refrigeration cycle apparatus having the same.

A microchannel heat exchanger is known that has microchannels formed by microfabrication such as chemical etching as flow paths for liquids and gases (Patent Document 1). Microchannels are formed between metal plates, for example, by laminating a plurality of metal plates having fine grooves. The laminated metal plates are integrated by diffusion bonding or the like and assembled with the header.

A microchannel heat exchanger is used by being incorporated in a refrigeration cycle device or the like equipped with a refrigerant circuit. and a channel group. Heat is transferred between the heating fluid and the heated fluid via the partition separating the first microchannel group and the second microchannel group.
According to the microchannel heat exchanger, it is possible to ensure a large heat transfer area per unit volume compared to conventional heat exchangers by having fine-diameter microchannels. Therefore, further miniaturization and higher performance of devices are expected through the practical application of devices including microchannel heat exchangers.

By the way, piping through which fluid flows is connected to heat exchangers, not limited to microchannel heat exchangers. The fluid flowing through the piping contains foreign matter such as copper powder generated during construction of the piping and iron powder caused by abrasion of iron-based members such as compressors.
In order to prevent such foreign matter from clogging the restrictor or the like, in Patent Document 2, the foreign matter is collected by a sludge filter installed inside the pipe. Moreover, in Patent Document 3, a foreign matter is attracted by a magnet installed outside the pipe.

Patent No. 5185975 JP-A-10-300286 JP 2012-57858 A

Even if a filter for collecting foreign matter is installed in the piping upstream of the heat exchanger, if fine foreign matter such as iron powder passes through the filter and flows into the header of the heat exchanger, the flow velocity will decrease. It tends to clump inside small headers. Then, since the diameter of the microchannel is fine with respect to the mass of aggregated foreign matter, the microchannel may be blocked by the foreign matter.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a microchannel heat exchanger capable of preventing clogging of flow paths, and a refrigeration cycle apparatus having the same.

A microchannel heat exchanger of the present invention comprises a heat exchanger body having a plurality of microchannels, an upstream header communicating with the plurality of microchannels and into which a fluid is introduced, and a magnet provided in the upstream header. characterized by

In the microchannel heat exchanger of the present invention, the magnets are preferably provided at the bottom of the upstream header.

In the microchannel heat exchanger of the present invention, the upstream header has an introduction part into which a fluid is introduced, and a wall body that separates the introduction part side and the microchannel side inside the upstream header. It is preferable that a channel through which a fluid flows is formed between and.

In the microchannel heat exchanger of the present invention, the interior of the upstream header preferably widens as it approaches the microchannel.

Preferably, the microchannel heat exchanger of the present invention further comprises a downstream header through which fluid flows out from the plurality of microchannels, and the downstream header is also provided with a magnet.

In the microchannel heat exchanger of the present invention, the plurality of microchannels are
A first microchannel group and a second microchannel group are included, and the direction of the fluid flowing through the first microchannel group and the direction of the fluid flowing through the second microchannel group are preferably opposite or orthogonal.

Further, the refrigeration cycle apparatus of the present invention includes the above-described microchannel heat exchanger, a compressor that compresses a refrigerant that is a fluid, a first heat exchanger that exchanges heat between the refrigerant and a heat source, and a pressure of the refrigerant. and a second heat exchanger for exchanging heat between the refrigerant and the heat load, wherein the microchannel heat exchanger includes a first microchannel group and a second microchannel group, and a second It is characterized by exchanging heat between the first refrigerant flowing through one microchannel group and the second refrigerant flowing through the second microchannel group.

Since the flow velocity of the fluid inside the upstream header is low, foreign matter contained in the fluid tends to agglomerate inside the upstream header. On the other hand, since the flow velocity of the fluid is small, the foreign matter can be attracted to the magnet and held by the magnetic force against the flow of the fluid.
Therefore, according to the present invention, even if foreign matter agglomerates inside the upstream header, the foreign matter, including the agglomerated mass, can be held by the magnet, so that the foreign matter can be prevented from going to the microchannel. . By doing so, it is possible to suppress the aggregation of foreign matter at least at the opening of the microchannel, so that even if the microchannel is easily clogged due to its small diameter, clogging of the microchannel can be prevented.
Moreover, since the condensed contaminants can be held by the magnet inside the upstream header where the flow velocity is low, the contaminants can be efficiently collected and the risk of blockage of the microchannels can be reduced.

1 is an exploded perspective view showing a microchannel heat exchanger; FIG. (a) is a schematic diagram of a microchannel group that the heat exchanger shown in FIG. 1 has. (b) is a schematic diagram of a group of microchannels having different channel shapes. FIG. 2 is a diagram schematically showing a refrigerant circuit of a refrigeration cycle device such as an air conditioner; (a) is a perspective view of the microchannel heat exchanger according to the first embodiment. (b) is a cross-sectional view along line IVb-IVb of (a), showing an upstream header and microchannels. (a) and (b) are diagrams showing a microchannel heat exchanger according to a second embodiment. (b) is a cross-sectional view taken along line Vb-Vb of (a). FIG. 10 is a diagram showing a microchannel heat exchanger according to a modification of the second embodiment; (a) and (b) are exploded perspective views showing a counterflow microchannel heat exchanger according to a modification. (b) is a sectional view taken along line VIIb-VIIb of (a). (a) and (b) are exploded perspective views showing a cross-flow microchannel heat exchanger according to another modification. (b) is a cross-sectional view taken along line VIIIb-VIIIb of (a).

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[Configuration of microchannel heat exchanger]
First, referring to FIGS. 1 and 2, the configuration of a microchannel heat exchanger 1 common to each embodiment will be described.
As shown in FIG. 1, the microchannel heat exchanger 1 is assembled with a heat exchanger body 10 having a plurality of microchannels 100 as flow paths, and the heat exchanger body 10 communicating with the plurality of microchannels 100. An upstream header 20 and a downstream header 30 are provided.
A plurality of microchannels 100 includes a first microchannel group 101 and a second microchannel group 102 .

The microchannel heat exchangers 1 and 2 (FIGS. 4 and 5) of each embodiment are provided with magnets 41 in the header 20 for collecting foreign matter such as iron powder mixed in the refrigerant, as will be described later. be the main feature.

The microchannel heat exchanger 1 is incorporated in, for example, a refrigerant circuit 80 shown in FIG. 3 to constitute a refrigeration cycle device 8 such as an air conditioner, a refrigerator, and a water heater. The microchannel heat exchanger 1 is connected to other components (81-84) of the refrigeration cycle by piping.

A refrigerant circuit 80 provided in the refrigeration cycle device 8 includes a compressor 81 that compresses refrigerant, a first heat exchanger 82 that exchanges heat between the refrigerant and a heat source, and an expansion valve or the like that reduces the pressure of the refrigerant. It comprises a part 83 , a second heat exchanger 84 for exchanging heat between the refrigerant and the heat load, and the microchannel heat exchanger 1 .
When the refrigeration cycle device 8, which is an air conditioner, is operated for cooling, the microchannel heat exchanger 1 uses the first heat exchanger 82 to exchange heat with the outside air (heat source) to condense the refrigerant and the second heat. Heat is exchanged with the room air (heat load) by the exchanger 84 to exchange heat with the evaporated refrigerant. Such heat exchange can provide subcooling to the refrigerant.

The microchannel heat exchanger 1 includes a relatively high-temperature refrigerant (a first refrigerant that is a heating refrigerant) flowing through the refrigerant circuit 80 and a relatively low-temperature refrigerant (a second refrigerant that is a refrigerant to be heated) flowing through the refrigerant circuit 80. refrigerant).
The first coolant is, for example, the coolant that flows out from the first heat exchanger 82 in FIG. 3 and corresponds to the first microchannel group 101 . The second refrigerant is, for example, the refrigerant flowing out of the second heat exchanger 84 in FIG. 3 and corresponds to the second microchannel group 102 .

The microchannel heat exchanger 1 shown in FIG. 1 is of a parallel flow type in which the direction in which the first refrigerant flows through the microchannels 100 is the same as the direction in which the second refrigerant flows through the microchannels 100 . The direction in which the first coolant flows through the microchannels 100 is indicated by dashed arrows, and the direction in which the second coolant flows through the microchannels 100 is indicated by solid arrows.

(header)
The upstream header 20 is divided into a first upstream header 21 communicating with the first microchannel group 101 and a second upstream header 22 communicating with the second microchannel group 102 . An opening on the upstream side of the microchannel 100 faces the inside of each of the first upstream header 21 and the second upstream header 22 . At this time, the upstream openings of the microchannels 100 of the first microchannel group 101 are connected to the first upstream header 21, and the upstream openings of the microchannels 100 of the second microchannel group 102 are connected to the second upstream header. 22.

The downstream header 30 is divided into a first downstream header 31 communicating with the first microchannel group 101 and a second downstream header 32 communicating with the second microchannel group 102 . An opening on the downstream side of the microchannel 100 faces the inside of each of the first downstream header 31 and the second downstream header 32 . At this time, the downstream opening of each microchannel 100 of the first microchannel group 101 is connected to the first downstream header 31, and the downstream opening of each microchannel 100 of the second microchannel group 102 is connected to the second upstream header. 32.

Both the first and second upstream headers 21 and 22 and the first and second downstream headers 31 and 32 allow the refrigerant to flow smoothly through the microchannel 100 in consideration of the respective pressure losses of the first refrigerant and the second refrigerant. Adequate flow cross-sectional area and volume are ensured so that the The channel cross-sectional area of each header 21 , 22 , 31 , 32 is sufficiently large relative to the diameter of the microchannel 100 . As will be described later, if the flow velocity of the refrigerant inside the headers 20 and 30 is low, it is advantageous to collect foreign substances mixed in the refrigerant. .

The upstream header 20 can be configured in an appropriate form such that first and second upstream headers 21 and 22 are formed on the upstream side of the heat exchanger body 10 . Further, the downstream header 30 can be configured in an appropriate form in which first and second downstream headers 31 and 32 are formed on the downstream side of the heat exchanger body 10 .
According to the illustrated example of the upstream header 20, the upstream header 20 includes an upper wall 20A continuous with the upper surface of the heat exchanger body 10, a lower wall 20B continuous with the lower surface of the heat exchanger body 10, and an upper wall 20A. and a side wall 20C forming first and second upstream headers 21 and 22 between the bottom wall 20B. The downstream header 30 is similarly constructed.

The interior of the upstream header 20 of this embodiment gradually widens as it approaches the microchannel 100 . The width of the upstream header 20 in plan view gradually widens to the same dimension as the width of the heat exchanger body 10 . The interior of each of the first and second upstream headers 21 and 22 of the upstream header 20 also gradually widens as it approaches the microchannel 100 .
Not limited to this embodiment, the upstream header 20 and the downstream header 30 may be formed with a constant width.

(Flow of first refrigerant and second refrigerant)
The first refrigerant is introduced into the first upstream header 21 of the upstream header 20 from the introduction portion 201 to which the refrigerant pipe is connected, as indicated by the white arrow in FIG. of microchannels 100. The first refrigerant that has flowed through those microchannels 100 joins at the first downstream header 31 of the downstream header 30 and flows out from the discharge portion 301 to the refrigerant circuit 80 .
As indicated by black arrows in FIG. distributed to channels 100; The second refrigerant that has flowed through those microchannels 100 joins at the second downstream header 32 of the downstream header 30 and flows out from the discharge portion 302 to the refrigerant circuit 80 .

The microchannel heat exchanger 1 is not limited to a parallel flow type, and may be a counter flow type or a cross flow type. In the counter-flow type, for example, as shown in FIG. 7, the direction in which the first coolant flows in the first microchannel group 101 and the direction in which the second coolant flows in the second microchannel group 102 are opposed to each other. The microchannel heat exchanger 1 shown in FIG. 3 is also described as countercurrent. In the cross-flow system, for example, as shown in FIG. 8, the direction in which the first coolant flows through the first microchannel group 101 and the direction in which the second coolant flows through the second microchannel group 102 are orthogonal.

(Microchannel)
The microchannel 100 is formed in an arbitrary cross-sectional shape by microfabrication such as etching in the base material of the heat exchanger body 10 made of a metal material such as stainless steel, copper, copper alloy, aluminum, and aluminum alloy. ing.
As an example, the flow path size of the microchannel 100 is less than 1 mm in diameter. The length and number of the microchannels 100 are appropriately determined according to the heat exchange capacity required for the heat exchanger body 10 .
The flow path size of the microchannel 100 may be set to a diameter of several millimeters or less at which the influence of the surface tension of the liquid phase flowing through the microchannel 100 appears. The size of the flow path of the microchannel 100 can be set to an appropriate size generally included in the category of microchannels.

A heat exchanger body 10 having microchannels 100 is constructed by stacking a plurality of metal plates 11 in which fine grooves 11A are formed at a predetermined pitch, as shown in FIG. 2(a), for example.
The heat exchanger main body 10 is formed in a rectangular parallelepiped shape as a whole by laminating metal plates 11 . The laminated metal plates 11 are integrated by a method such as diffusion bonding.
The headers 20 and 30 can be attached to the heat exchanger body 10 by diffusion bonding.

In each metal plate 11, as shown in FIG. 2(a), a large number of grooves 11A having a semicircular cross section are formed in parallel along a direction perpendicular to the plane of the drawing. A microchannel 100 having a circular cross section is formed between the adjacent metal plates 11 by overlapping the surfaces on which the grooves 11A are formed.
The microchannel 100 may be formed between a metal plate 11 in which a groove 11B having a rectangular cross section is formed and an adjacent metal plate 11, as shown in FIG. 2(b).

The microchannels 100 are arranged in one direction (x direction) in the in-plane direction of the metal plate 11 and are also arranged in the direction (y direction) in which the metal plates 11 are laminated. A set of microchannels 100 arranged in the x-direction along the surface of the metal plate 11 shall be referred to as a "stage" of the heat exchanger.
In the example shown in FIGS. 2(a) and 2(b), the microchannels 100 are arranged such that the microchannels 100 in the lower stage are positioned directly below the microchannels 100 in a certain stage. The arrangement is not limited to this, and the microchannels 100 in a certain stage and the microchannels 100 in the lower stage may be arranged (staggered) so as to be shifted in the x direction.

The first microchannel group 101 consists of a plurality of stages of microchannels 100 positioned every other stage in the stacking direction y.
A second microchannel group 102 consists of the remaining tiers of microchannels 100 .
In FIGS. 1, 2(a) and 2(b), the openings of the first microchannel group 101 through which the first coolant flows are shown in white, and the openings of the second microchannel group 102 through which the second coolant flows are shown in black. there is Heat exchange is performed between the first refrigerant and the second refrigerant via the partition wall (metal substrate) that separates the first microchannel group 101 and the second microchannel group 102 .
For efficient heat exchange, it is preferable that the first microchannel groups 101 and the second microchannel groups 102 are alternately arranged in the stacking direction y as shown in FIGS. 1, 2(a) and 2(b). .
However, the first microchannel group 101 and the second microchannel group 102 are not necessarily arranged alternately. Also, the first microchannel group 101 and the second microchannel group 102 do not necessarily have to be separated for each stage.

The microchannel heat exchanger 1 according to the first embodiment (FIG. 4) will be described below.
As mentioned above, the microchannel heat exchanger 1 has magnets 41 provided in the upstream header 20 .
FIG. 4(b) shows the first upstream header 21 corresponding to the first refrigerant. The second upstream header 22 (not shown) is similarly configured.

Refrigerant flowing through the refrigerant circuit 80 is mixed with foreign matter 9 such as iron powder caused by abrasion of iron-based members such as the compressor, and copper powder generated by flaring or the like during construction of the refrigerant pipe 5 . there is The particle size of the foreign matter 9 such as iron powder is about 150 μm at most, and is very fine. Therefore, even if a strainer (not shown) is installed in the refrigerant pipe 5 upstream of the microchannel heat exchanger 1 to catch the foreign matter 9 in the refrigerant, fine foreign matter 9 that has passed through the strainer is may flow into

The flow velocity of the refrigerant that has flowed into the upstream header 20 from the refrigerant pipe 5 decreases inside the upstream header 20 . Then, the influence of the refrigerant flow is small inside the upstream header 20 where the refrigerant stays until it is distributed to the microchannels 100, so that the foreign matter 9 mixed in the refrigerant tends to condense due to the attractive force between the foreign matter 9. In order to prevent clogging of the microchannels 100 by aggregated foreign matter 9 , the upstream header 20 is provided with a magnet 41 that attracts the foreign matter 9 .
FIG. 4B schematically shows the magnetic flux φ related to the magnet 41. As shown in FIG. The magnetic flux φ passes through the upstream header 20, which is typically non-magnetic and made of copper alloy, aluminum alloy, or the like, in the plate thickness direction.
It should be noted that the upstream header 20 may be made of a magnetic material as long as the magnetic flux φ passes through it.

The magnet 41 of this embodiment is a permanent magnet, but may be an electromagnet having an iron core and coils. The magnet 41 can be provided at any location on the upstream header 20 .

In this specification, the magnetic force generated between the magnet and the ferromagnetic material due to the magnetic field associated with the magnet attracts (magnetically attracts) the ferromagnetic material to the magnet and holds it. shall be
The foreign matter 9 mixed in the refrigerant is typically iron powder, and the iron powder is a ferromagnetic material. The iron powder is attracted to the magnet 41 by magnetic force and is magnetized.

The foreign matter 9 attracted to the magnet 41 is not necessarily a ferromagnetic substance represented by iron powder or an aggregate of ferromagnetic substances, but a ferromagnetic substance and a non-magnetic substance such as copper powder (diamagnetic substance, normal magnetic substance, etc.). Magnetic substances and antiferromagnetic substances) are also applicable to aggregated and grown substances.
In the process of flowing through the refrigerant pipes of the refrigerant circuit 80 or inside the upstream header 20 where the flow velocity is low, when fine iron powder is integrated with copper powder, dust, etc., the copper powder and dust are attracted to the magnet 41 together with the iron powder. be adsorbed.
When the magnetic material in the foreign matter 9 attracted to the magnet 41 is magnetized, the foreign matter 9 attracts another foreign matter 9 including a magnetic material.
Since the flow velocity of the coolant inside the upstream header 20 is low, the adsorbed foreign matter 9 can be kept in place by the magnetic force without being significantly affected by the flow of the coolant.
The size, magnetic flux density, etc. of the magnet 41 can be appropriately determined in consideration of the flow velocity of the coolant, the size of the header 20, and the like.

Since the interior of the upstream header 20 of the present embodiment gradually widens as it approaches the microchannel 100, the flow velocity of the coolant decreases toward the back (downstream) of the upstream header 20. FIG. Therefore, on the far side of the upstream header 20, the foreign matter 9 can be reliably attracted by the magnet without being affected by the flow of the coolant.
As with the upstream header 20 , the magnets 41 are preferably shaped to expand toward the microchannel 100 .

In this embodiment, when the microchannel heat exchanger 1 is installed in the equipment housing, the microchannel 100 is arranged in a horizontal or near-horizontal state. At this time, the upstream header 20 is horizontally adjacent to the side surface of the heat exchanger body 10 on which the microchannels 100 are arranged.
The magnet 41 of the present embodiment has a plate shape and is provided on the lower wall 20B (bottom portion) of the upstream header 20 as shown in FIG. 4(b). Magnets 41 are provided in both regions of first upstream header 21 and second upstream header 22 .
The magnet 41 may be provided on either the upper surface side or the lower surface side of the lower wall 20B, and may be embedded in the lower wall 20B. The magnet 41 does not necessarily have to be provided on the bottom wall 20B. A magnet 41 may be provided at the lower end of the side wall 20C.
Even if there is a gap between the lower wall 20B and the magnet 41, it is allowed as long as the foreign matter 9 is attracted to the magnet 41. This case also corresponds to the fact that the magnets 41 are provided in the upstream header 20 .

While the refrigerant stays inside the upstream header 20, foreign matter in the refrigerant settles toward the lower wall 20B due to its own weight due to the difference in density from the refrigerant. The foreign matter 9 that has settled down and has approached the lower wall 20B is attracted to the magnet 41 provided on the lower wall 20B through the lower wall 20B.
When the magnet 41 is arranged vertically below the upstream header 20 so that the foreign matter 9 sinks toward the magnet 41 in this way, the gravity causes the foreign matter 9 to approach the magnet 41 . The foreign matter 9 can be more reliably attracted to the magnet 41 by the strong magnetic force.
When the gravity contributes to the movement of the foreign object 9 toward the magnet 41, the magnetic force required for the magnet 41 is smaller than when the foreign object 9 is attracted to the magnet 41 only by the magnetic force. Therefore, instead of using an expensive magnet with a strong magnetic force, an inexpensive and easily available magnet such as a ferrite magnet can be used as the magnet 41 .

It is preferable that the magnet 41 be provided over the entire area of the lower wall 20B in order to attract the sedimented foreign matter 9 over the entire area of the lower wall 20B. The magnets 41 provided on the bottom wall 20B may be integrated or divided.
In addition, providing the magnet 41 in a part of the lower wall 20B is also permitted. For example, the magnets 41 may be provided only in a region near the introduction portion 201 through which the refrigerant is introduced from the refrigerant pipe 5 to the first upstream header 21 , or only in a region near the heat exchanger body 10 .

If the upstream header 20 were not provided with the magnet 41, the foreign matter 9 in the refrigerant introduced from the refrigerant pipe 5 into the upstream header 20 would condense and flow toward the heat exchanger main body 10 together with the refrigerant. It gathers at the opening of the small-diameter microchannel 100 . Then, when the foreign matter 9 adheres to the vicinity of the opening of the microchannel 100, the foreign matter 9 adheres to the vicinity of the opening, and the foreign matter 9 aggregates. be.

According to this embodiment in which the upstream header 20 is provided with the magnets 41 , even if the foreign matter 9 in the refrigerant aggregates inside the upstream header 20 , the foreign matter 9 including the aggregated foreign matter 9 can be retained by the magnets 41 . Therefore, it is possible to avoid the foreign matter 9 from going to the microchannel 100 . As a result, aggregation of the foreign matter 9 can be suppressed at least at the opening of the microchannel 100, so even if the diameter of the microchannel 100 is small, clogging of the microchannel 100 can be prevented.

Since the magnet 41 is provided in the upstream header 20 where the flow velocity of the refrigerant is low, the magnetic force of the magnet 41 can reliably attract the foreign matter 9 against the flow of the refrigerant inside the upstream header 20 . Even if magnets are provided in the refrigerant pipes 5 or the like having a higher flow velocity than inside the upstream header 20 , it is difficult to sufficiently attract the foreign matter 9 as the magnets 41 provided in the upstream header 20 do. In other words, the provision of the magnets 41 in the upstream header 20, which has a large flow passage cross-sectional area with respect to the refrigerant pipes 5 and thus a low refrigerant flow velocity, is significant.

Moreover, inside the header 20 where the flow velocity is low, the foreign matter 9 tends to aggregate, and the aggregated foreign matter 9 is attracted to the magnet 41. Therefore, the foreign matter 9 mixed in the refrigerant is efficiently collected to prevent clogging by the foreign matter 9. can reduce risk. Also, by suppressing the outflow of the foreign matter 9 into the refrigerant circuit 80 by collecting the foreign matter 9 with the magnet 41, the amount of the foreign matter 9 in the refrigerant flowing into the upstream header 20 can be suppressed. The risk of blockage of channel 100 can be reduced.

By the way, even when the downstream header 30 is provided with the magnet 42 ( FIG. 1 ), the magnet 42 can attract and hold the foreign matter 9 in the refrigerant similarly to the magnet 41 of the upstream header 20 . The flow velocity of the refrigerant flowing into the downstream header 30 from the microchannels 100 is lower than the flow velocity in the refrigerant piping that discharges the refrigerant from the downstream header 30 . Therefore, in the downstream header 30 where the flow velocity is low like the upstream header 20, the foreign matter 9 in the refrigerant can be reliably attracted to the magnet 42. FIG.
In addition, the foreign matter 9 is collected by the magnet 42 to prevent the foreign matter 9 from flowing out to the refrigerant circuit 80, so that the risk of clogging the microchannel 100 by the foreign matter 9 can be reduced.

[Second embodiment]
A second embodiment of the present invention will now be described with reference to FIG.
The following description focuses on matters that differ from the first embodiment. The same symbols are given to the same components as in the first embodiment.

The microchannel heat exchanger 2 according to the second embodiment is characterized in that it has a wall 24 inside the upstream header 20 that separates the refrigerant introduction side from the microchannel 100 side.

The upstream header 20 is divided into a first upstream header 21 and a second upstream header 22 . The wall 24 consists of a first wall 241 located in the first upstream header 21 and a second wall 242 located in the second upstream header 22 . FIG. 5(b) shows the first wall 241 located in the first upstream header 21. As shown in FIG.

As shown in FIGS. 5A and 5B, the first wall 241 separates the introduction portion 201 side and the microchannel 100 side in the first upstream header 21 .
The first wall body 241 includes a plate-shaped guide portion 241A facing the introduction portion 201, and a plate-shaped guide portion 241A that is continuous with the lower side of the guide portion 241A and extends toward the heat exchanger main body 10 along the lower wall 20B. and an access portion 241B.
The approach portion 241B is bent toward the microchannel 100 side with respect to the guide portion 241A extending in the vertical direction. The guide portion 241A and the approach portion 241B as a whole present an L-shaped cross section as shown in FIG. 5(b).

The approaching portion 241B of the first wall 241 extends along the magnet 41 near the magnet 41 provided on the lower wall 20B. Between the approaching portion 241B and the magnet 41, an adsorption channel 25 is formed through which the refrigerant flowing from the introduction portion 201 flows toward the heat exchanger main body 10. As shown in FIG.
A terminal end 25 A of the adsorption channel 25 is separated from the heat exchanger body 10 .

The refrigerant introduced into the first upstream header 21 of the upstream header 20 through the introduction portion 201 is guided downward by the guide portion 241A of the first wall 241 and flows into the adsorption channel 25 . In the course of the refrigerant flowing through the attraction channel 25 in a state of being close to the magnet 41 , the foreign matter 9 in the refrigerant is attracted to the magnet 41 by magnetic force. After that, the refrigerant flows from the end 25A of the adsorption channel 25 into between the guide portion 241A and the heat exchanger main body 10, and further flows into the first microchannel group 101. As shown in FIG.
Since the adsorption channel 25 widens as it approaches the microchannel 100 in the same way as the shape of the upstream header 20, the flow velocity of the refrigerant decreases as it goes deeper into the adsorption channel 25. FIG. Therefore, the foreign matter 9 in the refrigerant can be reliably attracted to the magnet 41 without being hindered by the flow of the refrigerant, particularly on the far side of the attraction channel 25 .

The second wall 242 (FIG. 5(a)) separates the introduction portion 202 side and the microchannel 100 side in the second upstream header 22 . The second wall body 242 also has a guide portion and an approach portion, though not specifically illustrated. An attraction channel 25 is formed between the approaching portion of the second wall 242 and the magnet 41 .
The refrigerant introduced into the second upstream header 22 through the introduction portion 202 is guided downward by the guide portion of the second wall 242 and flows into the adsorption channel 25 . In the course of the refrigerant flowing through the attraction channel 25 in a state of being close to the magnet 41 , the foreign matter 9 in the refrigerant is attracted to the magnet 41 by magnetic force. After that, the refrigerant flows between the second wall 242 and the heat exchanger main body 10 and flows into the second microchannel group 102 .

According to the second embodiment, the coolant introduced into the upstream header 20 flows through the adsorption flow path 25 through the wall member 24 , so that the coolant always flows near the magnets 41 . Therefore, the magnetic force related to the magnetic field generated by the magnet 41 sufficiently acts on the foreign matter 9 , so that the foreign matter 9 in the refrigerant can be more reliably attracted to the magnet 41 .
Here, if the upper end T of the guide portion 241A abuts against the upper wall 20A, the entire amount of introduced refrigerant flows into the adsorption channel 25, which is preferable. However, it is permissible that there is a gap between the upper end T and the upper wall 20A.

According to the second embodiment, even if the microchannel heat exchanger 2 is not installed in the direction in which the foreign matter 9 sinks vertically downward toward the magnet 41, the refrigerant mixed with the foreign matter 9 does not reach the wall 24. is guided near the magnet 41 and flows through the adsorption channel 25 . The foreign matter 9 is attracted to the magnet 41 while the refrigerant flows close to the magnet 41 to the terminal end 25A of the attraction channel 25 .
That is, according to the second embodiment, since the header 20 is provided with the walls 24 that form the adsorption flow paths 25, the degree of freedom in the orientation of installing the microchannel heat exchanger 2 is improved.

The wall 24 can be configured in an appropriate form according to the positions of the introduction portions 201 and 202 provided in the upstream header 20, the positions of the magnets 41, and the like.
For example, upstream header 27 shown in FIG. Refrigerant is introduced from the refrigerant pipe 5 through the introduction portion 203 toward the lower wall 20B. A magnet 41 is provided on the side wall 20</b>C of the upstream header 27 .
The wall body 28 extends along the extension direction of the axis of the introduction part 203 and separates the introduction part 203 side from the microchannel 100 side.
Foreign matter 9 in the coolant is attracted to the magnet 41 while the coolant introduced from the introduction portion 203 flows through the adsorption channel 29 between the wall 28 and the magnet 41 .

FIG. 7 shows a counterflow microchannel heat exchanger 3 .
In the microchannel heat exchanger 3, the direction in which the first refrigerant flows through the first microchannel group 101 (broken arrow) and the direction in which the second refrigerant flows through the second microchannel group 102 (solid arrow) are opposite to each other. do. The dashed and solid arrows are parallel and opposite to each other.
In such a counterflow type, the upstream header 21 for the first refrigerant and the downstream header 32 for the second refrigerant are arranged at one end of the microchannel 100, and the downstream header 31 for the first refrigerant and the downstream header 32 for the second refrigerant are arranged at the other end of the microchannel 100. A second refrigerant upstream header 22 is provided.

At one end of the microchannel 100, the upstream header 21 and the downstream header 32 are preferably integrally constructed in a size corresponding to the allowable installation space. These upstream header 21 and downstream header 32 constitute a header structure 51 .
The same applies to the upstream header 22 and the downstream header 31 located on the other end side. These upstream header 22 and downstream header 31 constitute another header structure 52 .

Unlike the parallel flow type (FIGS. 1, 4 and 5) in which the upstream header 21 for the first refrigerant and the upstream header 22 for the second refrigerant are adjacent, in the counterflow type, the upstream header 21 and the upstream header 21 are adjacent to each other. Headers 22 are spaced at opposite ends of microchannel 100 .
When the upstream headers 21 and 22 of the first refrigerant and the second refrigerant are separated from each other, it is possible to easily install fixtures such as the walls 24 and the magnets 41 inside the respective upstream headers 21 and 22 . If they are spaced apart, the positions of the fixtures do not interfere, and even if the amount occupied by the installation of the fixtures is taken into consideration, the predetermined flow passage cross-sectional area and volume required inside each of the headers 21 and 22 are secured. This is because it is easy to
Therefore, according to the counterflow type microchannel heat exchanger 3, the degree of freedom in setting the wall 24 and the magnets 41 and the size and shape of the wall 24 and the magnets 41 is improved.
Specifically, while the walls 24 having a shape suitable for collecting the foreign matter 9 are installed in each of the upstream headers 21 and 22, the overall size of the header structure 51 and the size of the header structure 52 are increased. can be suppressed.

FIG. 8 shows a cross-flow microchannel heat exchanger 4 .
In the microchannel heat exchanger 4, the direction in which the first refrigerant flows through the first microchannel group 101 (broken arrow) and the direction in which the second refrigerant flows through the second microchannel group 102 (solid arrow) are orthogonal. do.
The microchannel heat exchanger 4 comprises an upstream header 61 and a downstream header 71 for the first refrigerant and an upstream header 62 and a downstream header 72 for the second refrigerant.

As shown in FIG. 8(b), magnets 41 and wall bodies 24 are installed in both upstream headers 61 and 62 of the first refrigerant and the second refrigerant, respectively.
In the cross flow type as well, since the upstream header 61 and the upstream header 62 are separated from each other, the wall 24 and the magnets 41 must be installed, and the wall 24 and the magnets 41 must be installed in the same manner as in the above-described counter flow type. The degree of freedom regarding size, shape, etc. is improved.

In addition to the above, it is possible to select the configurations described in the above embodiments or to change them to other configurations as appropriate without departing from the gist of the present invention.

The heat exchanger body 10 of the microchannel heat exchanger is divided in the length direction of the microchannel 100, and the upstream portion of the heat exchanger body 10 and the downstream portion of the heat exchanger body 10 are separated. Intermediate headers to relay may be provided. In this case, the intermediate header corresponds to an upstream header into which the refrigerant is introduced from the upstream portion of the heat exchanger body 10 and flows into the microchannels 100 formed in the downstream portion of the heat exchanger body 10. do. A magnet 41 may be provided in this intermediate header to attract the foreign matter 9 in the refrigerant.

1 to 4 Microchannel heat exchanger 5 Refrigerant pipe 8 Refrigeration cycle device 9 Foreign matter 10 Heat exchanger body 11 Metal plates 11A, 11B Grooves 20, 27 Upstream header 20A Upper wall 20B Lower wall (bottom)
20C side wall 21 first upstream header 22 second upstream header 24, 28 wall 25, 29 adsorption channel 25A end 30 downstream header 31 first downstream header 32 second downstream header 41 magnet 42 magnet 51, 52 header structure 61 1 upstream header 62 2nd upstream header 71 1st downstream header 72 2nd downstream header 80 refrigerant circuit 81 compressor 82 first heat exchanger 83 pressure reducing section 84 second heat exchanger 100 microchannel 101 first microchannel group 102 2 microchannel groups 201, 202 introduction part 203 introduction part 241 first wall 241A guide part 241B approaching part 242 second wall 301, 302 discharge part T upper end φ magnetic flux

Claims (6)

a heat exchanger body having a plurality of microchannels;
an upstream header communicating with the plurality of microchannels and into which a fluid is introduced;
and a magnet provided on the upstream header. ,
The upstream header is
an introducing portion into which the fluid is introduced;
a wall that separates the introduction portion side and the microchannel side inside the upstream header;
has
A channel through which the fluid flows is formed between the wall and the magnet,
A microchannel heat exchanger characterized by: the magnet is provided at the bottom of the upstream header;
A microchannel heat exchanger according to claim 1. the interior of the upstream header widens as it approaches the microchannel;
Microchannel heat exchanger according to claim 1 or 2 . further comprising a downstream header through which the fluid flows out from the plurality of microchannels;
the downstream header is also provided with a magnet;
4. A microchannel heat exchanger according to any one of claims 1-3 . The plurality of microchannels are
including a first group of microchannels and a second group of microchannels,
a direction of the fluid flowing through the first group of microchannels;
facing or perpendicular to the direction of the fluid flowing through the second microchannel group;
5. A microchannel heat exchanger according to any one of claims 1-4 . a microchannel heat exchanger according to any one of claims 1 to 5 ;
a compressor for compressing the fluid refrigerant;
a first heat exchanger for exchanging heat between the refrigerant and a heat source;
a decompression unit that reduces the pressure of the refrigerant;
A refrigerant circuit including a second heat exchanger that exchanges heat between the refrigerant and a heat load,
The microchannel heat exchanger is
including a first group of microchannels and a second group of microchannels,
exchanging heat between the first refrigerant flowing through the first group of microchannels and the second refrigerant flowing through the second group of microchannels;
A refrigeration cycle device characterized by:

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