JP2017187254A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure a contact area of a vapor-phase refrigerant and a heat transfer pipe.SOLUTION: A heat exchanger (13) includes a shell (20), and a plurality of heat transfer pipes (30) disposed inside of the shell (20). The plurality of heat transfer pipes (30) are arranged in parallel with each other. Each of the plurality of heat transfer pipes (30) has a first corner portion (31) as a part having a contour of a radius of curvature smaller than a radius of a circle having an area same as a cross-section of each of the plurality of heat transfer pipes (30) on a longitudinal cross-section vertical to a longitudinal direction of the plurality of heat transfer pipes (30). The first corner portion (31) configures a lowermost part of the plurality of heat transfer pipes (30) in a vertical direction. The first corner portion (31) of the first heat transfer pipe (30A) is disposed on a position horizontally separating from an apex (33p) of a second heat pipe (30B).SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a heat exchanger.

  A shell and tube heat exchanger is known as a heat exchanger used for condensing the refrigerant. FIG. 9 is a cross-sectional view of a conventional shell and tube heat exchanger described in Patent Document 1.

  As shown in FIG. 9, the conventional shell and tube heat exchanger includes a shell 1 and a plurality of heat transfer tubes 2. The shell 1 has an inlet 4 and an outlet 5. A high-temperature and gas-phase refrigerant is introduced into the shell 1 from the inlet 4. The refrigerant is cooled by the cooling water flowing through the heat transfer tube 2 and is liquefied on the surface of the heat transfer tube. As a result, a liquid-phase refrigerant is generated. The liquid-phase refrigerant flows downward and is discharged from the outlet 5 to the outside of the shell 1.

JP-A-8-159611

  In order to improve the performance of the heat exchanger, it is important to ensure a sufficient contact area between the vapor such as the gas-phase refrigerant and the heat transfer tube.

That is, this disclosure
Shell,
A plurality of heat transfer tubes disposed inside the shell;
With
The plurality of heat transfer tubes are arranged in parallel to each other,
Each of the plurality of heat transfer tubes has a curvature radius profile that is smaller than a radius of a circle having the same area as the cross-sectional area of each of the plurality of heat transfer tubes in a vertical cross section perpendicular to the longitudinal direction of each of the plurality of heat transfer tubes. Having a first corner that is a portion indicating
The first corner portion constitutes a lowermost portion of each of the plurality of heat transfer tubes in the vertical direction,
Each of the plurality of heat transfer tubes includes an apex located at the top in the vertical direction,
When the upper heat transfer tube selected from the pair of heat transfer tubes adjacent to each other in the vertical direction is defined as a first heat transfer tube, and the lower heat transfer tube is defined as a second heat transfer tube, the first heat transfer tube is defined. The first corner portion of the heat tube provides a heat exchanger that is in a position horizontally separated from the apex of the second heat transfer tube.

  According to the technology of the present disclosure, a sufficient contact area between steam such as a gas-phase refrigerant and a heat transfer tube can be ensured.

FIG. 1 is a configuration diagram of a refrigeration cycle apparatus according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view taken along line II-II of the condenser according to an embodiment of the present disclosure. FIG. 3 is a partially enlarged view of FIG. FIG. 4 is an enlarged view showing the cross-sectional shape of the heat transfer tube in detail. FIG. 5 is an explanatory diagram of the operation of the condenser of this embodiment. FIG. 6 is a cross-sectional view of a heat transfer tube according to a modification. FIG. 7 is a cross-sectional view of a heat transfer tube according to another modification. FIG. 8 is a cross-sectional view of a condenser according to still another modification. FIG. 9 is a schematic cross-sectional view of a conventional shell and tube heat exchanger. FIG. 10 is an operation explanatory diagram of a conventional condenser.

(Knowledge that became the basis of this disclosure)
According to the knowledge of the present inventors, the conventional shell and tube heat exchanger shown in FIG. 9 has the following drawbacks. As shown in FIG. 10, when the refrigerant is introduced into the shell, the refrigerant is cooled on the surface of the heat transfer tube 2a located on the upper side to generate a liquid-phase refrigerant. The liquid phase refrigerant flows down from the bottom of the heat transfer tube 2a and adheres to the top of the heat transfer tube 2b located on the lower side. Since the liquid phase refrigerant flows along the surface of the heat transfer tube 2b, the surface of the heat transfer tube 2b is entirely covered with the liquid phase refrigerant film. When the surface of the heat transfer tube 2b is entirely covered with a liquid phase refrigerant film, the contact surface between the heat transfer tube 2b and the gas phase refrigerant is lost. As a result, the heat transfer tube 2b cannot sufficiently exhibit the heat transfer performance. The amount of the liquid-phase refrigerant that flows down from the upper heat transfer tube 2a to the lower heat transfer tube 2b gradually increases as the liquid-phase refrigerant moves from the upper side to the lower side. The thickness of the liquid-phase refrigerant film also gradually increases as the liquid-phase refrigerant moves from the upper side to the lower side. If the heat transfer tube 2b cannot exhibit sufficient heat transfer performance, the heat exchanger cannot also exhibit sufficient performance (heat exchange performance).

  According to the above knowledge, if it is possible to prevent the entire surface of the heat transfer tube located on the lower side from being covered with the condensate (liquid phase refrigerant) generated on the surface of the heat transfer tube located on the upper side, Heat transfer performance can be fully demonstrated.

The heat exchanger according to the first aspect of the present disclosure is:
Shell,
A plurality of heat transfer tubes disposed inside the shell;
With
The plurality of heat transfer tubes are arranged in parallel to each other,
Each of the plurality of heat transfer tubes has a curvature radius profile that is smaller than a radius of a circle having the same area as the cross-sectional area of each of the plurality of heat transfer tubes in a vertical cross section perpendicular to the longitudinal direction of each of the plurality of heat transfer tubes. Having a first corner that is a portion indicating
The first corner portion constitutes a lowermost portion of each of the plurality of heat transfer tubes in the vertical direction,
Each of the plurality of heat transfer tubes includes an apex located at the top in the vertical direction,
When the upper heat transfer tube selected from the pair of heat transfer tubes adjacent to each other in the vertical direction is defined as a first heat transfer tube, and the lower heat transfer tube is defined as a second heat transfer tube, the first heat transfer tube is defined. The first corner of the heat pipe is at a position in the horizontal direction away from the apex of the second heat transfer pipe.
In other words, the first corner of the first heat transfer tube does not overlap the apex of the second heat transfer tube when viewed from the vertical direction.

  When the first heat transfer tube and the second heat transfer tube satisfy the positional relationship as described above, the condensate (liquid phase refrigerant) generated on the surface of the first heat transfer tube can be prevented from flowing down to the top of the second heat transfer tube. . Thereby, it can avoid that the surface of a 2nd heat exchanger tube is entirely covered with a condensed liquid, and the contact surface of a 2nd heat exchanger tube and a vapor | steam is fully ensured. As a result, sufficient heat transfer performance is exhibited also in the second heat transfer tube, and as a result, the heat exchanger can exhibit high performance.

  In the second aspect of the present disclosure, for example, the first corner portion of the heat exchanger according to the first aspect is a portion positioned at one end of each of the plurality of heat transfer tubes in the horizontal direction. Each of the heat transfer tubes further includes a second corner portion that is a portion located at the other end in the horizontal direction, and in the longitudinal section, the first corner portion of the first heat transfer tube and the second heat transfer tube. The first corner portion of the first heat transfer tube exists on a first reference line parallel to the vertical direction, and the second corner portion of the first heat transfer tube and the second corner of the second heat transfer tube. The part exists on a second reference line parallel to the vertical direction. In other words, the first reference line is in contact with the first corner portion of the first heat transfer tube and the second corner portion of the second heat transfer tube, and the second reference line. Are in contact with the second corner of the first heat transfer tube and the second corner of the second heat transfer tube. According to such a configuration, the liquid-phase refrigerant generated on the surface of the heat transfer tube gathers evenly at each of the first corner and the second corner and flows down downward. Since the amount of the liquid phase refrigerant can be equally distributed to the left and right, the liquid phase refrigerant film is thicker than when the liquid phase refrigerant flows downward from only one location of the heat transfer tube. Can be suppressed.

  In the third aspect of the present disclosure, for example, in the longitudinal section of the heat exchanger according to the first or second aspect, the plurality of heat transfer tubes are arranged in a lattice pattern. According to the 3rd aspect, the effect by a 1st aspect can be acquired more fully.

  In the fourth aspect of the present disclosure, for example, in the longitudinal section of the heat exchanger according to the first or second aspect, the plurality of heat transfer tubes are arranged in an alternating pattern. According to such a configuration, the flow direction of the gas-phase refrigerant in the shell becomes irregular, and a strong stirring action acts on the gas-phase refrigerant. As a result, the heat transfer performance of the heat transfer tube can be sufficiently exhibited.

  In the fifth aspect of the present disclosure, for example, each of the plurality of heat transfer tubes of the heat exchanger according to any one of the first to fourth aspects has a cross-sectional area of each of the plurality of heat transfer tubes in the longitudinal section. 3 or more than 3 parts that exhibit a radius of curvature smaller than the radius of a circle having the same area. According to the 5th aspect, the effect demonstrated in the 1st aspect can be acquired reliably.

  In the sixth aspect of the present disclosure, for example, in the vertical cross section of the heat exchanger according to any one of the first to fifth aspects, a regular polygon having a minimum area surrounding each of the plurality of heat transfer tubes is provided. It is an equilateral triangle. According to such a shape, a heat exchanger tube can be easily produced by forming a circular tube. Moreover, when the heat transfer tube has a cross-sectional shape that approximates an equilateral triangle, it is easy to earn a horizontal distance between the first corner and the apex.

  In the seventh aspect of the present disclosure, for example, each of the outlines of the plurality of heat transfer tubes in the longitudinal section of the heat exchanger according to the sixth aspect is more than the equilateral triangle with the smallest area surrounding the heat transfer tubes. Each of the plurality of heat transfer tubes has a concave portion drawn down toward the inside. According to the seventh aspect, the liquid-phase refrigerant is likely to gather at the corners.

  In the eighth aspect of the present disclosure, for example, in the longitudinal section of the heat exchanger according to any one of the first to seventh aspects, the center of each of the plurality of heat transfer tubes passes through and is parallel to the vertical direction. With respect to the reference line, the contours of the plurality of heat transfer tubes are asymmetric. According to such a configuration, the liquid-phase refrigerant generated on the surface of the heat transfer tube is easily collected at the first corner. It is possible to quickly remove the liquid phase refrigerant from the surface of the heat transfer tube.

  In the ninth aspect of the present disclosure, for example, the first corner of the heat exchanger according to any one of the first to eighth aspects is positioned at one end of each of the plurality of heat transfer tubes in the horizontal direction. Each of the plurality of heat transfer tubes further includes a second corner portion which is a portion located at the other end in the horizontal direction, and the second corner portion is more than the first corner portion. Is also located above in the vertical direction. According to such a configuration, the liquid-phase refrigerant generated on the surface of the heat transfer tube can be easily collected at the first corner and quickly removed from the surface of the heat transfer tube.

A refrigeration cycle apparatus according to the tenth aspect of the present disclosure is provided.
An evaporator for heating the refrigerant;
A compressor for compressing the refrigerant;
The condenser for condensing the refrigerant;
With
The condenser is constituted by any one of the heat exchangers of the first to ninth aspects.

  According to the 10th aspect, the refrigerating-cycle apparatus which can exhibit the outstanding COP (coefficient of performance) can be provided. In particular, a high effect is obtained when the refrigeration cycle apparatus is operated under the condition that the flow rate (mass flow rate) of the refrigerant increases.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

  As shown in FIG. 1, the refrigeration cycle apparatus 10 includes an evaporator 11, a compressor 12, a condenser 13, a flow rate control valve 14, and flow paths 16a to 16d. The outlet of the evaporator 11 is connected to the suction port of the compressor 12 by a flow path 16a. The discharge port of the compressor 12 is connected to the inlet of the condenser 13 by the flow path 16b. The outlet of the condenser 13 is connected to the inlet of the flow control valve 14 by a flow path 16c. The outlet of the flow control valve 14 is connected to the inlet of the evaporator 11 by a flow path 16d. The flow paths 16a and 16b are vapor paths, and the flow paths 16c and 16d are liquid paths.

  In the evaporator 11, the refrigerant is heated and evaporated. Thereby, a gas-phase refrigerant (refrigerant vapor) is generated. The gas-phase refrigerant is sucked into the compressor 12 and compressed. A high-temperature and high-pressure gas-phase refrigerant is supplied from the compressor 12 to the condenser 13. The refrigerant is cooled and liquefied in the condenser 13. Thereby, a liquid phase refrigerant (refrigerant liquid) is generated. The liquid phase refrigerant is returned from the condenser 13 to the evaporator 11 via the flow control valve 14.

  The refrigeration cycle apparatus 10 is an air conditioner for business use or home use, for example. The heat medium cooled by the evaporator 11 is supplied into the room and used for cooling the room. Or the heat medium heated with the condenser 13 is supplied indoors, and is used for indoor heating. The heat medium is, for example, water. However, the refrigeration cycle apparatus 10 is not limited to an air conditioner, and may be another apparatus such as a chiller or a heat storage device.

  As shown in FIG. 2, the condenser 13 is constituted by a shell and tube heat exchanger. Specifically, the condenser 13 includes a shell 20 and a plurality of heat transfer tubes 30. The plurality of heat transfer tubes 30 are arranged inside the shell 20. The shell 20 has an inlet 20a and an outlet 20b. A channel 16b and a channel 16c can be connected to the inlet 20a and the outlet 20b, respectively. In the vertical direction, the inlet 20a of the shell 20 is located at the top, and the outlet 20b of the shell 20 is located at the bottom. For example, the inlet 20 a is positioned above the heat transfer tubes 30 in the vertical direction, and the outlet 20 b is positioned below the heat transfer tubes 30 in the vertical direction. A gas phase refrigerant is introduced into the shell 20 through the inlet 20a. When a heat medium having a temperature lower than the temperature of the refrigerant is passed through the heat transfer tube 30, the refrigerant is cooled and condensed on the surface of the heat transfer tube 30. The liquid-phase refrigerant is discharged to the outside of the shell 20 through the outlet 20b. In the present embodiment, the shell 20 has a rectangular cross-sectional shape. However, the shell 20 may have a circular cross-sectional shape. The shell 20 may be a pressure vessel.

  Each of the plurality of heat transfer tubes 30 has a linear shape. The plurality of heat transfer tubes 30 are arranged in parallel with each other inside the shell 20. Headers (not shown) are provided at both ends of the plurality of heat transfer tubes 30, respectively. The heat medium is distributed from the header to each heat transfer tube 30, and the heat medium is collected from each heat transfer tube 30 to the header.

  FIG. 2 shows a cross section of the condenser 13 perpendicular to the longitudinal direction of the heat transfer tube 30. Hereinafter, in the present specification, a section perpendicular to the longitudinal direction of the heat transfer tube 30 is referred to as a “longitudinal section”. In the present embodiment, the longitudinal section is parallel to the vertical direction. Except for both ends of the heat transfer tube 30, the cross-sectional shape of the heat transfer tube 30 is the same at any position in the longitudinal direction.

  In the longitudinal section shown in FIG. 2, the plurality of heat transfer tubes 30 are arranged in a lattice pattern. When a plurality of vertical reference lines Vr parallel to the vertical direction and a plurality of horizontal reference lines Hr parallel to the horizontal direction are defined, above each intersection of the plurality of vertical reference lines Vr and the plurality of horizontal reference lines Hr In addition, the heat transfer tube 30 (specifically, the center of gravity G of the heat transfer tube 30) is located. The plurality of vertical reference lines Vr are arranged at equal intervals. A plurality of horizontal reference lines Vr are also arranged at equal intervals. The plurality of heat transfer tubes 30 are arranged in a matrix in the vertical direction (longitudinal direction) and the horizontal direction (lateral direction). Between the heat transfer tubes 30 adjacent to each other in the horizontal direction, a moderately wide space is secured as a refrigerant flow path. Similarly, a moderately wide space is secured between the heat transfer tubes 30 adjacent to each other in the vertical direction as a refrigerant flow path.

  As shown in FIG. 3, the heat transfer tube 30 has a non-circular cross-sectional shape. Specifically, each heat transfer tube 30 has a corner portion 31 (also referred to as “first corner portion 31”). The corner portion 31 is a portion showing a contour having a radius of curvature smaller than the radius of a circle having the same area as the cross-sectional area of the heat transfer tube 30 in the longitudinal section. Moreover, the corner | angular part 31 comprises the part located in the lowest part of the heat exchanger tube 30 in a perpendicular direction.

  As shown in FIG. 3, each heat transfer tube 30 includes an apex 33 p located at the top in the vertical direction. The upper heat transfer tube 30 selected from a pair of heat transfer tubes 30 adjacent to each other in the vertical direction is defined as a first heat transfer tube 30A, and the lower heat transfer tube 30 is defined as a second heat transfer tube 30B. The first heat transfer tube 30A and the second heat transfer tube 30B are located on a common vertical reference line Vr. The corner portion 31 of the first heat transfer tube 30A is at a position away from the apex 33p of the second heat transfer tube 30B in the horizontal direction. When the first heat transfer tube 30A and the second heat transfer tube 30B satisfy such a positional relationship, the liquid-phase refrigerant generated on the surface of the first heat transfer tube 30A is separated from the apex 33p of the second heat transfer tube 30B in the horizontal direction. Gather at the same position and flow downwards. That is, it is possible to avoid the liquid refrigerant generated on the surface of the first heat transfer tube 30A from flowing down to the apex 33p of the second heat transfer tube 30B. Thereby, it can avoid that the surface of the 2nd heat exchanger tube 30B is entirely covered with a liquid phase refrigerant | coolant, and the contact surface of the 2nd heat exchanger tube 30B and a gaseous-phase refrigerant | coolant is fully ensured. As a result, sufficient heat transfer performance is exhibited also in the second heat transfer tube 30B, and as a result, the performance of the condenser 13 is sufficiently exhibited.

  As shown in FIG. 3, the heat transfer tube 30 further includes another corner portion 32 (also referred to as “second corner portion 32”) and a top portion 33 in addition to the first corner portion 31. The first corner portion 31 is a portion located at one end in the horizontal direction. The 2nd corner | angular part 32 is a part located in the other end in a horizontal direction. Not only the first corner portion 31 but also the second corner portion 32 constitutes a portion located at the bottom of the heat transfer tube 30 in the vertical direction. That is, the first corner portion 31 is located at the same height as the second corner portion 32 in the vertical direction. The top portion 33 is a portion located on the top of the heat transfer tube 30 in the vertical direction. The vertex 33p is a position included in the top 33. In the longitudinal section, the first corner portion 31 of the first heat transfer tube 30A and the first corner portion 31 of the second heat transfer tube 30B are present on the first reference line V1 parallel to the vertical direction. In the longitudinal section, the second corner portion 32 of the first heat transfer tube 30A and the second corner portion 32 of the second heat transfer tube 30B exist on the second reference line V2 parallel to the vertical direction. The distance D between the first reference line V1 and the second reference line V2 is equal to the dimension (width) of the heat transfer tube 30 in the horizontal direction. That is, in this embodiment, the cross-sectional shape of the heat transfer tube 30 is symmetric with respect to the vertical reference line Vr. According to such a configuration, the liquid-phase refrigerant generated on the surface of the heat transfer tube 30 gathers evenly at each of the first corner portion 31 and the second corner portion 32 and flows down downward. Since the amount of the liquid-phase refrigerant can be equally distributed to the left and right, the liquid-phase refrigerant film is thicker than when the liquid-phase refrigerant flows downward from only one location of the heat transfer tube 30. Can be suppressed. Moreover, since the position of the 1st corner | angular part 31 and the position of the 2nd corner | angular part 32 are aligned regarding the perpendicular direction, the liquid-phase refrigerant | coolant which arose on the surface of the 1st heat exchanger tube 30A is the corner | angular of the 2nd heat exchanger tube 30B. It can be generally avoided that it flows down to portions other than the portions 31 and 32. Therefore, the area of the surface of the second heat transfer tube 30B covered with the liquid-phase refrigerant generated on the surface of the first heat transfer tube 30A can be minimized.

  The “first corner portion 31”, the “second corner portion 32”, and the “top portion 33” can also be defined as follows. A portion showing an arcuate contour having a radius of curvature smaller than the radius of a circle having the same area as the cross-sectional area of the heat transfer tube 30 in the vertical cross section is defined as “corner”. The “corner” positioned at the top in the vertical direction can be defined as the “top”. According to this embodiment, the 1st corner | angular part 31, the 2nd corner | angular part 32, and the top part 33 all show the circular-arc outline of the same curvature radius in a longitudinal cross section.

  According to the present embodiment, the heat transfer tube 30 has three or three portions (corner portions) showing contours of a radius of curvature smaller than the radius of a circle having the same area as the cross-sectional area of the heat transfer tube 30 in the longitudinal section. Have beyond. Specifically, in the longitudinal section, a regular polygon having a minimum area surrounding the heat transfer tube 30 is a regular triangle. According to such a shape, the heat exchanger tube 30 of this embodiment can be easily produced by forming a circular tube. Further, when the heat transfer tube 30 has a cross-sectional shape that approximates an equilateral triangle, it is easy to earn a horizontal distance between the first corner portion 31 and the apex 33p. However, the triangle with the smallest area surrounding the heat transfer tube 30 is not limited to an equilateral triangle, and may be an isosceles triangle, a right triangle, or an unequal triangle. Furthermore, the rectangle with the smallest area surrounding the heat transfer tube 30 may be a rectangle, a square, a rhombus, or an unequal side rectangle. The upper limit of the number of corners is not particularly limited, but is 6 for example in consideration of ease of molding.

  According to this embodiment, the outline of the heat transfer tube 30 in the longitudinal section is composed of a plurality (three) of curved portions and a plurality (three) of straight portions. The plurality of curved portions correspond to the first corner portion 31, the second corner portion 32, and the top portion 33, respectively. The plurality of straight line portions are located between the curved portion and the curved portion, respectively. Of course, the outline of the heat transfer tube 30 may be formed of a smooth curve except for portions corresponding to the first corner portion 31, the second corner portion 32, and the top portion 33.

  As shown in FIG. 4, the contour of the heat transfer tube 30 in the longitudinal section is a concave portion 30p, 30q that is pulled down toward the inside of the heat transfer tube 30 from the equilateral triangle 40 having the smallest area that virtually surrounds the heat transfer tube 30. And 30r. The concave portions 30p, 30q, and 30r face the sides of the regular triangle 40, respectively. The concave portion 30 p is a portion between the first corner portion 31 and the second corner portion 32. The concave portion 30q is a portion between the first corner portion 31 and the top portion 33. The concave portion 30 r is a portion between the second corner portion 32 and the top portion 33. The concave portion 30p is a portion corresponding to the bottom surface of the heat transfer tube 30, and is inclined with respect to the horizontal plane. The inclination angle θ of the concave portion 30p with respect to the horizontal plane is, for example, in the range of 1 to 5 degrees. The outline of the heat transfer tube 30 has the same concave shape on three sides. That is, the outline of the heat transfer tube 30 in the longitudinal section has rotational symmetry with respect to the center of gravity G (for example, three-fold rotational symmetry). According to such a configuration, the heat transfer tube 30 of this embodiment can be easily manufactured by forming a circular tube. Since the heat transfer tube 30 has no directionality, it is very easy to assemble a large number of heat transfer tubes 30 on a header or the like. That is, it is easy to manufacture the heat exchanger 13 using the heat transfer tube 30.

  In addition, since the bottom surface of the heat transfer tube 30 between the first corner portion 31 and the second corner portion 32 is formed in a concave shape upward, the liquid-phase refrigerant can be used in the first corner portion 31 or the first corner portion 31. It is easy to gather at the two corners 32. As a result, it is possible to continuously ensure contact between the bottom surface of the heat transfer tube 30 and the gas-phase refrigerant.

  Next, the operation of the condenser 13 will be described in detail with reference to FIG.

  When the gas-phase refrigerant is introduced into the shell 20, a part of the refrigerant is cooled by the heat medium flowing through the first heat transfer tube 30A and condensed on the surface of the first heat transfer tube 30A. The liquid-phase refrigerant generated on the surface of the first heat transfer tube 30A flows along the surface of the first heat transfer tube 30A and collects at the corners 31 and 32. Thereafter, the liquid-phase refrigerant flows down from the top 33 of the second heat transfer tube 30B to a position shifted in the horizontal direction. Specifically, the liquid-phase refrigerant flows down from the corners 31 and 32 of the first heat transfer tube 30A to the vicinity of the surfaces of the corners 31 and 32 of the second heat transfer tube 30B, and the corners 31 and 32 of the second heat transfer tube 30B. Will flow down further down. That is, most of the liquid-phase refrigerant flows down near the corners 31 and 32 of the heat transfer tube 30 by its own weight, and is quickly removed from the surface of the heat transfer tube 30. Therefore, even when the heat transfer tubes 30 are arranged in a matrix, a sufficient contact area between the gas-phase refrigerant and the surface of the second heat transfer tube 30B can be secured. According to the present embodiment, the heat transfer performance of the heat transfer tube 30 can be sufficiently exhibited, so that the performance of the condenser 13 can be improved without increasing the number of heat transfer tubes 30, the surface area, and the like. Further, the bottom surface of the heat transfer tube 30 between the first corner portion 31 and the second corner portion 32 is formed in a concave shape upward. This configuration also contributes to securing a contact area between the gas-phase refrigerant and the surface of the heat transfer tube 30.

  Moreover, according to this embodiment, the following effects are also acquired. The gas-phase refrigerant introduced into the shell 20 is cooled by the heat medium inside the heat transfer tube 30. In the sensible heat change region, the density of the gas-phase refrigerant increases, so that a flow of the gas-phase refrigerant directed downward in the vertical direction is formed inside the shell 20.

  As shown in FIG. 10, in the condenser using the heat transfer tube 2 having a circular cross section, the flow of the gas-phase refrigerant is separated from the surface of the heat transfer tube 2 and stagnation occurs. At this time, buoyancy acts on the liquid-phase refrigerant collected near the bottom of the heat transfer tube 2. As a result, free fall of the liquid phase refrigerant from the heat transfer tube 2 is prevented.

  On the other hand, according to the present embodiment, such buoyancy is unlikely to act on the liquid-phase refrigerant collected at the corners 31 and 32. Therefore, the liquid phase refrigerant can smoothly flow downward from the corners 31 and 32 due to its own weight.

(Modification)
In the heat transfer tube 30c shown in FIG. 6, the surface between the first corner portion 31 and the second corner portion 32 is formed in a concave shape upward in the vertical direction. On the other hand, the surface between the top 33 and the first corner 31 is a flat surface inclined at an inclination angle β (for example, 60 degrees) with respect to the horizontal plane. The surface of the heat transfer tube 30c between the top 33 and the second corner 32 is also a flat surface that is inclined at an inclination angle β with respect to the horizontal plane. Even when only the bottom surface of the heat transfer tube 30c is formed in a concave shape upward as in the present modification, it is possible to prevent the liquid-phase refrigerant from staying on the bottom surface. Further, since the side surface inclination angle β can be increased as compared with the heat transfer tube 30 described with reference to FIG. 3, the liquid phase refrigerant can be quickly removed from the surface (side surface) of the heat transfer tube 30 c.

  Moreover, it is not essential that the part except the 1st corner | angular part 31, the 2nd corner | angular part 32, and the top part 33 is formed in concave shape. For example, the heat transfer tube 30 d illustrated in FIG. 7 includes a first corner portion 31, a second corner portion 32, and a top portion 33. The heat transfer tube 30d has a plurality of (three) surfaces. One of the plurality of surfaces is a surface (side surface) between the first corner portion 31 and the top portion 33. Another one of the plurality of surfaces is a surface (bottom surface) between the first corner portion 31 and the second corner portion 32. Another one of the plurality of surfaces is a surface (side surface) between the second corner portion 32 and the top portion 33. These plural surfaces are all flat surfaces. That is, the heat transfer tube 30d has no recess. Such a heat transfer tube 30d can be easily manufactured. Further, since the heat transfer tube 30d has no directionality, it is very easy to assemble a large number of heat transfer tubes 30d on a header or the like. That is, it is easy to manufacture the heat exchanger 13 using the heat transfer tube 30d. Furthermore, since the stress is less likely to concentrate on a specific portion of the heat transfer tube 30d, the heat transfer tube 30d is also excellent in pressure resistance.

  In the heat exchanger using the heat transfer tube 30d shown in FIG. 7, the first corner portion 31 of the heat transfer tube 30d is a portion located at the lowest position of the heat transfer tube 30d in the vertical direction. On the other hand, the second corner portion 32 of the heat transfer tube 30d is not the lowest portion of the heat transfer tube 30d in the vertical direction. In the vertical direction, the second corner 32 is located at a different height from the first corner 31. Specifically, the second corner portion 32 is located above the first corner portion 31 in the vertical direction. The surface (bottom surface) between the first corner portion 31 and the second corner portion 32 is inclined at an inclination angle γ with respect to the horizontal plane. The inclination angle γ is, for example, in the range of 1 to 29 degrees. The surface (side surface) between the first corner portion 31 and the top portion 33 is also inclined at an inclination angle β with respect to the horizontal plane. The inclination angle β is, for example, (γ + 60) degrees. In the longitudinal section, the outline of the heat transfer tube 30d is asymmetric with respect to a reference line Vr (vertical reference line) passing through the center of gravity G of the heat transfer tube 30d and parallel to the vertical direction. According to such a configuration, the liquid-phase refrigerant generated on the surface of the heat transfer tube 30 d is easily collected in the first corner portion 31. Similar to the heat transfer tube 30c described with reference to FIG. 6, it is possible to quickly remove the liquid-phase refrigerant from the surface of the heat transfer tube 30d.

  As shown in FIG. 8, the difference between the condenser 23 according to still another modification and the condenser 13 shown in FIG. 2 is the arrangement of the plurality of heat transfer tubes 30. According to this modification, in the longitudinal section of the condenser 23, the plurality of heat transfer tubes 30 are arranged in an alternating pattern. Also in this modification, the some heat exchanger tube 30 is located on each vertical reference line Vr. The position of the heat transfer tube 30 on one side of the vertical reference lines Vr adjacent to each other is shifted in the vertical direction from the position of the heat transfer tube 30 on the other side. Further, even if the heat transfer tubes 30 positioned on one of the adjacent vertical reference lines Vr are translated in the vertical direction, they do not overlap with the heat transfer tubes 30 positioned on the other of the adjacent vertical reference lines Vr. In addition, the interval between adjacent vertical reference lines Vr is adjusted. Similarly, the plurality of heat transfer tubes 30 are located on each horizontal reference line Hr. The position of the heat transfer tube 30 on one side of the horizontal reference lines Hr adjacent to each other is shifted in the horizontal direction from the position of the heat transfer tube 30 on the other side. Moreover, even if the heat transfer tubes 30 positioned on one of the adjacent horizontal reference lines Hr are translated in the horizontal direction, they do not overlap with the heat transfer tubes 30 positioned on the other of the adjacent horizontal reference lines Hr. Further, the interval between the horizontal reference lines Hr adjacent to each other is adjusted. For example, the interval between adjacent vertical reference lines Vr is equal to the interval between adjacent horizontal reference lines Hr. According to such a configuration, it is possible to achieve more efficient heat exchange.

  In the condenser 23, the shape of the flow path formed around the plurality of heat transfer tubes 30 is asymmetric with respect to at least one of the vertical direction and the horizontal direction. In this modification, the shape of the flow path inside the shell 20 of the condenser 23 is asymmetric with respect to the vertical direction. Specifically, in the longitudinal section, a flow path inside the shell 20 surrounded by three vertical reference lines Vr adjacent to each other and three horizontal reference lines Hr adjacent to each other is defined as a specific flow path. The specific flow path is symmetric with respect to the middle vertical reference line Vr selected from the three vertical reference lines Vr. On the other hand, the specific flow path is asymmetric with respect to the middle horizontal reference line Hr selected from the three horizontal reference lines Hr.

  According to the condenser 23 of this modification, the following effects can be obtained. First, according to this modification, the flow direction of the gas-phase refrigerant in the shell 20 becomes irregular, and a strong stirring action acts on the gas-phase refrigerant. As a result, the heat transfer performance of the heat transfer tube 30 can be sufficiently exhibited. In addition, the gas phase refrigerant is positive around the first corner portion 31 and the second corner portion 32 by combining the stir action acting on the gas phase refrigerant, the shape of the heat transfer tube 30, and the alternating pattern. Flowing. Further, separation of the liquid phase refrigerant from the first corner portion 31 and the second corner portion 32 is promoted, and the thickness of the liquid phase refrigerant film covering the surface of the heat transfer tube 30 is also reduced. As a result, the heat transfer performance of the heat transfer tube 30 can be more fully exhibited.

  The heat exchanger disclosed in the present specification can be used for various devices such as an air conditioner, a chiller, and a heat storage device.

DESCRIPTION OF SYMBOLS 10 Refrigeration cycle apparatus 11 Evaporator 12 Compressor 13, 23 Condenser 14 Flow control valve 20 Shell 30, 30c, 30d Heat transfer tube 30A 1st heat transfer tube 30B 2nd heat transfer tube 31 1st corner | angular part 32 2nd corner | angular part 33 Top 33 Vertex V1 First reference line V2 Second reference line Vr Vertical reference line Hr Horizontal reference line G Center of gravity

Claims (10)

Shell,
A plurality of heat transfer tubes disposed inside the shell;
With
The plurality of heat transfer tubes are arranged in parallel to each other,
Each of the plurality of heat transfer tubes has a curvature radius profile that is smaller than a radius of a circle having the same area as the cross-sectional area of each of the plurality of heat transfer tubes in a vertical cross section perpendicular to the longitudinal direction of each of the plurality of heat transfer tubes. Having a first corner that is a portion indicating
The first corner portion constitutes a lowermost portion of each of the plurality of heat transfer tubes in the vertical direction,
Each of the plurality of heat transfer tubes includes an apex located at the top in the vertical direction,
When the upper heat transfer tube selected from the pair of heat transfer tubes adjacent to each other in the vertical direction is defined as a first heat transfer tube, and the lower heat transfer tube is defined as a second heat transfer tube, the first heat transfer tube is defined. The heat exchanger according to claim 1, wherein the first corner of the heat tube is located in a horizontal direction away from the apex of the second heat transfer tube. The first corner is a portion located at one end of each of the plurality of heat transfer tubes in the horizontal direction,
Each of the plurality of heat transfer tubes further includes a second corner that is a portion located at the other end in the horizontal direction,
In the longitudinal section, the first corner of the first heat transfer tube and the first corner of the second heat transfer tube are present on a first reference line parallel to the vertical direction, 2. The heat according to claim 1, wherein the second corner of the first heat transfer tube and the second corner of the second heat transfer tube exist on a second reference line parallel to the vertical direction. Exchanger.   The heat exchanger according to claim 1 or 2, wherein the plurality of heat transfer tubes are arranged in a lattice shape in the longitudinal section.   The heat exchanger according to claim 1 or 2, wherein the plurality of heat transfer tubes are arranged in a staggered pattern in the longitudinal section.   Each of the plurality of heat transfer tubes has three or more than three portions showing a contour of a radius of curvature smaller than a radius of a circle having the same area as the cross-sectional area of each of the plurality of heat transfer tubes in the longitudinal section. The heat exchanger according to any one of claims 1 to 4.   6. The heat exchanger according to claim 1, wherein, in the longitudinal section, a regular polygon having a minimum area surrounding each of the plurality of heat transfer tubes is a regular triangle.   Each of the contours of the plurality of heat transfer tubes in the longitudinal section has a concave portion that is drawn toward the inside of each of the plurality of heat transfer tubes from the equilateral triangle having the smallest area surrounding the heat transfer tubes. The heat exchanger according to claim 6.   8. Any one of claims 1 to 7, wherein, in the longitudinal section, the contours of the plurality of heat transfer tubes are asymmetric with respect to a reference line that passes through the center of gravity of the plurality of heat transfer tubes and is parallel to the vertical direction. The heat exchanger according to claim 1. The first corner is a portion located at one end of each of the plurality of heat transfer tubes in the horizontal direction,
Each of the plurality of heat transfer tubes further includes a second corner that is a portion located at the other end in the horizontal direction,
The heat exchanger according to any one of claims 1 to 8, wherein the second corner is positioned above the first corner in the vertical direction. An evaporator for heating the refrigerant;
A compressor for compressing the refrigerant;
The condenser for condensing the refrigerant;
With
A refrigeration cycle apparatus in which the condenser is configured by the heat exchanger according to any one of claims 1 to 9.

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