US20120103587A1 - Heat exchanger - Google Patents

Abstract

A heat exchanger includes a refrigerant pipe in which a refrigerant flows and a heat exchanger fin coupled to the outer circumference of the refrigerant pipe. The heat exchanger fin includes a plate, a protrusion protruding from the plate, slits disposed at opposite sides of the protrusion to guide air to the protrusion, and a louver unit provided at the protrusion to perform heat exchange with the air having passed through the slits.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of Korean Patent Application No. 10-2010-0106371, filed on Oct. 28, 2010 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND
• 1. Field
• Embodiments of the present disclosure relate to a heat exchanger with an improved heat exchange structure.
• 2. Description of the Related Art
• A heat exchanger is mounted in devices operating based upon a refrigeration cycle, such as air conditioners or refrigerators. The heat exchanger includes a plurality of heat exchanger fins and a refrigerant pipe extending through the heat exchanger fins to guide a refrigerant. Contact area between the heat exchanger fins and external air introduced to the heat exchanger is increased to improve heat exchange efficiency between the refrigerant flowing in the refrigerant pipe and the external air.
• When the contact area between the heat exchanger fins and external air contacting the heat exchanger fins is large or when resistance applied to air contacting the heat exchanger fins is small, heat exchange efficiency is increased. However, if the contact area between the heat exchanger fins and air is too large, large resistance is applied to air passing through the heat exchanger fins. On the other hand, if the contact area is reduced to lower resistance applied to air, heat exchange efficiency is lowered. For this reason, it may be necessary to provide fins having an optimal shape based on the heat exchanger employed.
• For a heat exchanger used as an evaporator (that is, the refrigeration cycle performs a heating operation), if outdoor temperature is too low, the surface temperature of the heat exchanger is lowered to below zero Celsius, and moisture contained in outdoor air is attached to the surface of the cold heat exchanger in a frozen state, thereby reducing heat exchange efficiency of the heat exchanger.
SUMMARY
• It is an aspect of the present disclosure to provide a heat exchanger having a structure to effectively achieve heat exchange between air and heat exchanger fins.
• It is another aspect of the present disclosure to provide a heat exchanger having a structure to restrain frost formation on the surfaces of heat exchanger fins.
• Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure.
• In accordance with one aspect of the present disclosure, a heat exchanger includes a refrigerant pipe in which a refrigerant flows and a heat exchanger fin coupled to the outer circumference of the refrigerant pipe, wherein the heat exchanger fin includes a plate, a protrusion protruding from the plate, slits disposed at opposite sides of the protrusion to guide air to the protrusion, and a louver unit provided at the protrusion to perform heat exchange with the air having passed through the slits.
• The louver unit may include first cutouts provided at the protrusion and a plurality of guide plates provided in parallel to each other so that the guide plates are spaced apart from each other by the respective first cutouts, the first cutouts and the guide plates being alternately arranged.
• Each of the guide plates may have a width of 0.5 mm to 3 mm.
• The protrusion may include first inclined surfaces inclined relative to the plate, the guide plates may be provided at the first inclined surfaces, and the angle between the guide plates and the first inclined surfaces may be 10 to 60 degrees.
• Each of the slits includes second inclined surfaces inclined relative to the plate, a top surface formed between the second inclined surfaces, and a second cutout provided at the rear of the top surface.
• The top surface may have a width of 0.5 mm to 5 mm.
• The first inclined surfaces may be disposed at the plate in a symmetrical fashion, the distance between a line formed at the position where the first inclined surfaces join each other and the plate may constitute a height of the protrusion, and the protrusion may have a height of 0.5 mm to 4 mm.
• The first inclined surfaces may be disposed at the plate in a symmetrical fashion, the distance between a flat surface connected between the first inclined surfaces and the plate may constitute a height of the protrusion, and the protrusion may have a height of 0.5 mm to 4 mm.
• The heat exchanger fin may include a plurality of plates stacked at an interval.
• In accordance with another aspect of the present disclosure, a heat exchanger includes a tube to guide a fluid and a heat exchanger fin contacting the tub to perform heat exchange between the fluid and external air, wherein the heat exchanger fin includes location holes in which the tube is located in a supported state, a protrusion provided between the location holes, the protrusion protruding in the extension direction of the tube, a slit disposed at the periphery of the protrusion to accelerate air introduced to the protrusion, and a louver unit formed at the protrusion to perform heat exchange between the air having passed through the slit and the fluid.
• The louver unit may include a plurality of guide plates provided in parallel to each other so that the guide plates are spaced apart from each other and a plurality of first cutouts alternating with the guide plates.
• The protrusion may include first inclined surfaces disposed in a symmetrical fashion to form a ‘V’ shape, and the guide plates and the first cutouts may be provided at the first inclined surfaces.
• The angle between the first inclined surfaces and the guide plates provided at the first inclined surfaces may be 10 to 60 degrees.
• Each of the guide plates may have a width of 0.5 mm to 3 mm.
• The slit may include second inclined surfaces protruding in the extension direction of the tube, a top surface formed between the second inclined surfaces, and a second cutout provided at the rear of the top surface.
• The top surface may have a width of 0.5 mm to 5 mm.
• The protrusion may include first inclined surfaces disposed in a symmetrical fashion and a flat surface connected between the first inclined surfaces, the guide plates and the first cutouts being provided at the first inclined surfaces or the flat surface.
BRIEF DESCRIPTION OF THE DRAWINGS
• These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
• FIG. 1 is a perspective view illustrating a heat exchanger according to an embodiment of the present disclosure;
• FIG. 2 is a perspective view illustrating part of a heat exchanger fin ofFIG. 1;
• FIG. 3 is a front view ofFIG. 2;
• FIG. 4 is a sectional view taken along line I-I ofFIG. 3;
• FIG. 5 is an enlarged sectional view illustrating part ofFIG. 4;
• FIG. 6 is a view illustrating air flow around the heat exchanger fin ofFIG. 3;
• FIG. 7 is a sectional view taken along line II-II ofFIG. 6;
• FIG. 8 is a table illustrating heat exchange efficiency of the heat exchanger fin ofFIG. 3;
• FIG. 9 is a front view illustrating a conventional fin;
• FIG. 10 is a sectional view taken along line A-A ofFIG. 9;
• FIG. 11 is a front view illustrating a heat exchanger according to another embodiment of the present disclosure;
• FIG. 12 is a front view illustrating a heat exchanger according to another embodiment of the present disclosure;
• FIG. 13 is a sectional view taken along line III-III ofFIG. 12;
• FIG. 14 is a front view illustrating a heat exchanger according to another embodiment of the present disclosure;
• FIG. 15 is a sectional view taken along line IV-IV ofFIG. 14;
• FIG. 16 is a front view illustrating a heat exchanger according to another embodiment of the present disclosure;
• FIG. 17 is a sectional view taken along line V-V ofFIG. 16;
• FIG. 18 is a front view illustrating a heat exchanger according to yet another embodiment of the present disclosure; and
• FIG. 19 is a sectional view taken along line VI-VI ofFIG. 18.
DETAILED DESCRIPTION
• Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
• FIG. 1 is a perspective view illustrating a heat exchanger according to an embodiment of the present disclosure.
• As shown inFIG. 1, aheat exchanger10 includes arefrigerant pipe20, in which a refrigerant flows, andheat exchanger fins30 coupled to the outer circumference of therefrigerant pipe20.
• Therefrigerant pipe20 is configured in the shape of a hollow tube in which the refrigerant flows. Therefrigerant pipe20 is lengthened to increase heat exchange area between the refrigerant flowing in therefrigerant pipe20 and external air. However, it may be difficult to extend therefrigerant pipe20 in one direction due to spatial restrictions. Consequently, therefrigerant pipe20 is repeatedly bent at opposite ends of theheat exchanger10 in opposite directions to efficiently increase heat exchange area per unit volume.
• The refrigerant flowing in therefrigerant pipe20 is formed by mixing different Freon products exhibiting different properties. For example, R-134a and R410A may be used.
• The refrigerant may be phase changed (compressed) from a gas state to a liquid state to perform heat exchange with external air. On the other hand, the refrigerant may be phase changed (expanded) from a liquid state to a gas state to perform heat exchange with external air. When the refrigerant is phase changed from a gas state to a liquid state, theheat exchanger10 is used as a condenser. When the refrigerant is phase changed from a liquid state to a gas state, theheat exchanger10 is used as an evaporator.
• The refrigerant, flowing in therefrigerant pipe20, is compressed or expanded to discharge heat to the surroundings or to absorb heat from the surroundings. Theheat exchanger fins30 are coupled to therefrigerant pipe20 so that the refrigerant efficiently discharges or absorbs heat during compression or expansion.
• Theheat exchanger fins30 are disposed at a predetermined interval in the direction in which therefrigerant pipe20 extends.
• Theheat exchanger fins30 may be made of various metal materials, such as aluminum, exhibiting high thermal conductivity. Theheat exchanger fins30 are coupled to the outer circumference of therefrigerant pipe20 in a contact state to increase contact area between therefrigerant pipe20 and external air.
• The interval between theheat exchanger fins30 may be reduced to increase the number of theheat exchanger fins30. If the interval between theheat exchanger fins30 is too small, however, theheat exchanger fins30 may act as resistance to air F introduced to theheat exchanger10, as shown inFIG. 1, resulting in pressure loss. For this reason, the interval between theheat exchanger fins30 may be properly adjusted.
• FIG. 2 is a perspective view illustrating part of one of the heat exchanger fins ofFIG. 1,FIG. 3 is a front view ofFIG. 2,FIG. 4 is a sectional view taken along line I-I ofFIG. 3, andFIG. 5 is an enlarged sectional view illustrating part ofFIG. 4.
• As shown inFIGS. 2 to 5, theheat exchanger fin30 includes aplate40, aprotrusion70 protruding from theplate40, slits50 provided at opposite sides of theprotrusion70, and alouver unit60 provided at theprotrusion70.
• Theplate40 is made of an aluminum alloy. Theplate40 is thin. Theplate40 includes location holes32, through which therefrigerant pipe20 extends in a contact state.
• Each of the location holes32 contacts the outer circumference of therefrigerant pipe20 to support therefrigerant pipe20. Each of the location holes32 is formed in a shape corresponding to the outer circumference of therefrigerant pipe20 to surround therefrigerant pipe20.
• As shown inFIG. 2, each of the location holes32 protrudes frontward and rearward from theplate40 to stably support therefrigerant pipe20 and to increase contact area between therefrigerant pipe20 and theheat exchanger fin30 so that heat exchange is smoothly achieved.
• Theprotrusion70 protrudes frontward from theplate40.
• Theprotrusion70 includes firstinclined surfaces72 disposed at a predetermined angle relative to theplate40. The firstinclined surfaces72 are disposed on theplate40 in a symmetrical fashion to form a ‘V’ shape.
• The firstinclined surfaces72 guide air, passing through theslits50, to thelouver unit60. That is, air, accelerated while passing through theslits50, naturally flows along the firstinclined surfaces72 so that speed of the air is not reduced. The air flowing along the firstinclined surfaces72 contacts thelouver unit60 to perform heat exchange with the refrigerant flowing in therefrigerant pipe20, thereby increasing heat transfer efficiency.
• As previously described, the firstinclined surfaces72 are disposed on theplate40 in a symmetrical fashion to form a ‘V’ shape. Acontact line74 is formed vertically at a position where the firstinclined surfaces72 join each other. The distance between thecontact line74 and theplate40 constitutes a height H of theprotrusion70.
• If the height H of theprotrusion70 is increased, the area of the firstinclined surfaces72 increases, thereby increasing the contact area between the firstinclined surfaces72 and external air. If the height H of theprotrusion70 is excessively increased, however, the firstinclined surfaces72 act as resistance to external air. As a result, the speed of air is reduced and pressure of the air is reduced (pressure loss), thereby reducing heat transfer efficiency. The height H of theprotrusion70 is 0.5 mm to 4.0 mm.
• Meanwhile, the firstinclined surfaces72 may be disposed on the plate in a non-symmetrical fashion, which will be described in detail below in connection with aheat exchanger fin300 according to another embodiment of the present disclosure.
• Theslits50 are disposed at opposite sides of theprotrusion70.
• Theslits50 prevent moisture contained in external air from being attached to the surface of theheat exchanger fin30. Also, the slits accelerate external air introduced to theheat exchanger10 and guide the external air to theprotrusion70 and thelouver unit60. Each of theslits50 includes secondinclined surfaces52 inclined relative to theplate40, atop surface54 provided between the secondinclined surfaces52, and asecond cutout56 provided at the rear of thetop surface54.
• The secondinclined surfaces52 protrude from theplate40 so that the secondinclined surfaces52 are disposed at a predetermined angle relative to theplate40 to define a space, in which external air flows, between theplate40 and thetop surface54.
• Thetop surface54 is formed in an approximately trapezoidal shape. Thetop surface54 is disposed between the second inclined surfaces52. Air, passing through each of theslits50, is divided by thetop surface54 and flows along the front and rear of thetop surface54, resulting in turbulent flow. As a result, the air is further accelerated.
• Thetop surface54 may be formed in other shapes. For example, thetop surface54 may be formed in the shape of a triangle, a semicircle, an arc or a quadrangle. Even if thetop surface54 is formed in any one of the above-specified shapes, the same effect in that air, passing through each of theslits50, is divided by thetop surface54 is achieved.
• Anedge58 is formed betweentop surface54 and each of the second inclined surfaces52. Theedge58 prevents frost formation. Frost formation is a phenomenon in which moisture contained in external air is attached to the surface of theheat exchanger fin30 in a frozen state. Frost is formed at a flat surface on which more than a predetermined amount of moisture is easily collected. More than a predetermined amount of moisture is prevented from being collected by the provision of theedge58, thereby preventing or retarding frost formation.
• Thesecond cutout56 is provided at the rear of thetop surface54 to guide external air, introduced to theheat exchanger10, to thelouver unit60 and to minimize resistance applied to the air flowing along thetop surface54.
• When theheat exchanger10 is used as an evaporator to heat a room, the refrigerant, flowing in therefrigerant pipe20, is expanded from a liquid state to a gas state to absorb heat from the surroundings. As a result, the surface temperature of therefrigerant pipe20 is generally lowered to below zero degrees Celsius. Thesecond cutout56 retards heat exchange between therefrigerant pipe20 and thecorresponding slit50, thereby preventing frost formation.
• The width D of thetop surface54 may be 0.5 to 5.0 mm in consideration of resistance applied to air passing through thecorresponding slit50.
• Theslits50 are disposed at opposite sides of theprotrusion70. At least twoslits50 may be disposed in the vertical direction of theplate40 so that theslits50 are spaced apart from each other.
• When the slits are disposed in the vertical direction of theplate40 so that theslits50 are spaced apart from each other, the strength of theslits50 and theplate40 is higher than when the slits are disposed without separation.
• Thelouver unit60 is provided at theprotrusion70.
• Thelouver unit60 includesguide plates62 provided at the firstinclined surfaces72 andfirst cutout64 alternating with theguide plates62.
• Theguide plates62 are disposed at a predetermined angle relative to the first inclined surfaces72. Theguide plates62 are arranged in parallel to each other so that theguide plates62 are spaced apart from each other.
• External air, accelerated after having passed through theslits50, flows along the firstinclined surfaces72 and contacts theguide plates62 to perform heat exchange with theguide plates62. Theguide plates62 increase contact area between theheat exchanger fin30 and external air to increase heat exchange efficiency.
• When the pitch (width) P of each of theguide plates62 is small or when the inclination angle a between each of theguide plates62 and the firstinclined angle72 is small, contact area between theheat exchanger fin30 and external air increases. If the pitch P is too small or the inclination angle a is too large, however, speed of air passing through thelouver unit60 is reduced by theguide plates62, resulting in pressure loss. As a result, overall heat exchange efficiency is lowered. Consequently, the pitch P and the inclination angle a are properly adjusted. For example, the pitch P may be 0.5 mm to 3.0 mm and the inclination angle a may be 10 degrees to 60 degrees.
• Also, the edge of each of theguide plates62 prevents or retards frost formation, as previously described.
• Thefirst cutouts64 are provided at the firstinclined surfaces72 so that thefirst cutouts64 and theguide plates62 are alternately disposed. Thefirst cutouts64 guide external air, accelerated after having passed through theslits50, to flow along one side of each of theguide plates62, thereby effectively achieving heat transfer between theguide plates62 and external air.
• FIG. 6 is a view illustrating air flow around the heat exchanger fin ofFIG. 3, andFIG. 7 is a sectional view taken along line II-II ofFIG. 6.
• FIGS. 6 and 7 illustrate calculation results of air flow around theheat exchanger fin30 using computational fluid dynamics (CFD). In the drawings, lines indicate air flow direction, and lengths of the lines indicate air speed. Longer lengths of the lines represent higher air speed.
• As shown inFIGS. 6 and 7, air passing through theslits50 of theheat exchanger fin30 moves faster than air not passing through theslits50 since the air introduced into theslits50 is accelerated by thetop surface54 of each of theslits50.
• The air, accelerated by theslits50, flows to thelouver unit60 without reduction of air speed. As previously described, theslits50 accelerate air introduced into theslits50 and guide the introduced air to thelouver unit60.
• The air flows on the surfaces of theguide plates62 and between theguide plates62, i.e. at thefirst cutouts64, at high speed to perform heat exchange with theguide plates62.
• FIG. 8 is a table illustrating heat exchange efficiency of the heat exchanger fin ofFIG. 3.FIGS. 9 and 10 are a front view and a sectional view illustrating a conventional fin compared with the heat exchange efficiency of the heat exchanger fin ofFIG. 3.
• As shown inFIGS. 9 and 10, aconventional fin1 is provided at the middle thereof withsilts5 but does not include aprotrusion70 and alouver unit60, which are included in theheat exchanger fin30 ofFIG. 3.
• In the table ofFIG. 8, wind speed indicates speed of external air introduced to the fin, and fin pitch indicates the distance between the respective fins. Smaller pitch means that a larger number of fins may be disposed in a limited space.
• As the result of a comparison of heat transfer efficiency between the conventional fins and the inventive fins having the same pitch (1.5 mm), the inventive fins have approximately 7.4% to 8.2% higher heat transfer efficiency in all wind speed sections than the conventional fins.
• Also, even when the pitch of the inventive fins is increased from 1.5 mm to 1.7 mm, the inventive fins have higher heat transfer efficiency than the conventional fins having a pitch of 1.5 mm. This means that higher heat transfer efficiency is achieved using a smaller number of inventive fins, thereby reducing material costs.
• FIGS. 11 to 19 are front views and sectional views illustratingheat exchanger fins200,300,400,500 and600 according to other embodiments of the present disclosure.
• FIG. 11 illustrates aheat exchanger fin200 according to another embodiment of the present disclosure. Aslit250, protruding frontward from theheat exchanger fin200, is formed as a single body.
• FIGS. 12 and 13 illustrate aheat exchanger fin300 according to another embodiment of the present disclosure. Aprotrusion370 of theheat exchanger fin300 is formed in a non-symmetrical shape. That is, firstinclined surfaces372aand372bconstituting theprotrusion370 are formed in a non-symmetrical ‘V’ shape.
• An inclination angle β between the firstinclined surface372aand the front of aplate40 is larger than an inclination angle β′ between the firstinclined surface372band the front of theplate40. Consequently, the area of the firstinclined surface372ais smaller than that of the firstinclined surface372b. Also, acontact line374 at which the firstinclined surfaces372aand372bjoin each other deviates from the middle of theplate40.
• FIGS. 14 and 15 illustrate aheat exchanger fin400 according to another embodiment of the present disclosure.Guide plates462 provided at alouver unit60 of theheat exchanger fin400 have different inclination angles.
• That is, theguide plates462 may be provided at firstinclined surfaces72 so that theguide plates462 are at different inclination angles relative to the first inclined surfaces72.
• FIGS. 16 and 17 illustrate aheat exchanger fin500 according to another embodiment of the present disclosure.Slits50, protruding frontward from theheat exchanger fin500, are provided at only one side of a protrusion700.
• In this case, theslits50 are disposed at an external air introduction side.
• FIGS. 18 and 19 illustrate aheat exchanger fin600 according to yet another embodiment of the present disclosure. Aprotrusion670 of theheat exchanger fin600 includes aflat surface676.
• Theflat surface676 is provided between firstinclined surfaces672. The firstinclined surfaces672 may be symmetric with respect to theflat surface676. The distance between theflat surface676 and aplate40 constitutes the height of theprotrusion670. The height of theprotrusion670 is 0.5 mm to 4.0 mm.
• Guide plates62 may be selectively provided at the firstinclined surfaces672 or theflat surface676. Alternatively, theguide plates62 may be provided at both the firstinclined surfaces672 and theflat surface676.
• At least two of the previous embodiments may be combined. For example, when the embodiment ofFIGS. 12 and 13 and the embodiment ofFIGS. 14 and 15 are combined, theguide plates462 may be provided at the firstinclined surfaces372aand372bof theprotrusion370 formed in a non-symmetrical shape (characteristic of the embodiment of FIG.FIGS. 12 and 13) so that theguide plates462 are at different inclination angles to the firstinclined surfaces372aand372b(characteristic of the embodiment ofFIGS. 14 and 15).
• As is apparent from the above description, heat exchange between air and the heat exchanger fins of the embodiments of the present disclosure is effectively achieved, thereby improving heat exchange efficiency.
• Also, frost formation is restrained on the surfaces of the heat exchanger fins, thereby improving heat exchange efficiency.
• Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims (20)

1. A heat exchanger comprising:

a refrigerant pipe in which a refrigerant flows; and

a heat exchanger fin coupled to an outer circumference of the refrigerant pipe, wherein the heat exchanger fin comprises

a plate;

a protrusion protruding from the plate;

slits disposed at opposite sides of the protrusion to guide air to the protrusion; and

a louver unit provided at the protrusion to perform heat exchange with the air having passed through the slits.

2. The heat exchanger according toclaim 1, wherein the louver unit comprises:

first cutouts provided at the protrusion; and

a plurality of guide plates provided in parallel to each other so that the guide plates are spaced apart from each other by the respective first cutouts,

the first cutouts and the guide plates being alternately arranged.

3. The heat exchanger according toclaim 2, wherein each of the guide plates has a width of 0.5 mm to 3 mm.

4. The heat exchanger according toclaim 2, wherein the protrusion comprises first inclined surfaces inclined relative to the plate,

the guide plates are provided at the first inclined surfaces, and

an angle between the guide plates and the first inclined surfaces is 10 to 60 degrees.

5. The heat exchanger according toclaim 1, wherein each of the slits comprises:

second inclined surfaces inclined relative to the plate;

a top surface formed between the second inclined surfaces; and

a second cutout provided at a rear of the top surface.

6. The heat exchanger according toclaim 5, wherein the top surface has a width of 0.5 mm to 5 mm.

7. The heat exchanger according toclaim 4, wherein the first inclined surfaces are disposed at the plate symmetrically,

a distance between a line formed at a position where the first inclined surfaces join each other and the plate constitutes a height of the protrusion, and

the protrusion has a height of 0.5 mm to 4 mm.

8. The heat exchanger according toclaim 4, wherein the first inclined surfaces are disposed at the plate in a symmetrical fashion,

a distance between a flat surface connected between the first inclined surfaces and the plate constitutes a height of the protrusion, and

the protrusion has a height of 0.5 mm to 4 mm.

9. The heat exchanger according toclaim 1, wherein the heat exchanger fin comprises a plurality of plates stacked at an interval.

10. A heat exchanger comprising a tube to guide a fluid and a heat exchanger fin contacting the tube to perform heat exchange between the fluid and external air, wherein the heat exchanger fin comprises:

location holes in which the tube is located in a supported state;

a protrusion provided between the location holes, the protrusion protruding in an extension direction of the tube;

a slit disposed at a periphery of the protrusion to accelerate air introduced to the protrusion; and

a louver unit formed at the protrusion to perform heat exchange between the air having passed through the slit and the fluid.

11. The heat exchanger according toclaim 10, wherein the louver unit comprises:

a plurality of guide plates provided in parallel to each other so that the guide plates are spaced apart from each other; and

a plurality of first cutouts alternating with the guide plates.

12. The heat exchanger according toclaim 11, wherein the protrusion comprises first inclined surfaces disposed symmetrically to form a ‘V’ shape, and

the guide plates and the first cutouts are provided at the first inclined surfaces.

13. The heat exchanger according toclaim 12, wherein an angle between the first inclined surfaces and the guide plates provided at the first inclined surfaces is 10 to 60 degrees.

14. The heat exchanger according toclaim 13, wherein each of the guide plates has a width of 0.5 mm to 3 mm.

15. The heat exchanger according toclaim 14, wherein the slit comprises:

second inclined surfaces protruding in an extension direction of the tube;

a top surface formed between the second inclined surfaces; and

a second cutout provided at a rear of the top surface.

16. The heat exchanger according toclaim 15, wherein the top surface has a width of 0.5 mm to 5 mm.

17. The heat exchanger according toclaim 11, wherein the protrusion comprises:

first inclined surfaces disposed symmetrically; and

a flat surface connected between the first inclined surfaces,

the guide plates and the first cutouts being provided at the first inclined surfaces or the flat surface.

18. The heat exchanger according toclaim 10, wherein the louver unit comprises a plurality of guide plates spaced apart from each other and a plurality of first cutouts alternating with the guide plates,

the protrusion comprises first inclined surfaces disposed to form a ‘V’ shape, and

the guide plates and the first cutouts are provided at the first inclined surfaces.

19. The heat exchanger according toclaim 18, wherein the guide plates are provided at the first inclined surfaces at varying inclination angles relative to the first inclined surfaces.

20. The heat exchanger according toclaim 18, wherein the inclined surfaces are disposed to form a non-symmetrical ‘V’ shape.

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