Heat exchanger, refrigeration cycle apparatus, and air conditioner

Abstract

The present invention provides a fin tube-type heat exchanger that drains condensate water which is generated on the upwind side of fins and ensures heat transfer performance. The present invention also provides a refrigeration cycle apparatus and an air conditioner that each comprise the heat exchanger. Provided is a heat exchanger (100) comprising a plurality of heat transfer tubes (1) which are spaced in the direction of gravity and through which a refrigerant circulates in the circulation direction orthogonal to the direction of gravity, and a plurality of fins (10) which extend in the direction of gravity, which are spaced in the circulation direction, and which cross the plurality of heat transfer tubes (1), said heat exchanger exchanging heat with air that flows in the airflow direction orthogonal to the circulation direction, wherein the fins (10) are each provided with, on the upwind side of the airflow direction, a plurality of insertion holes (11) into which the plurality of respective heat transfer tubes (1) are inserted and upwind protruding sections (13) which protrude further on the upwind side than the upwind side ends of the heat transfer tubes (1), and the fins (10) each have, in the upwind protruding sections (13), upwind water guiding sections (20) which protrude in the circulation direction, which extend from the upwind side end (14) of that fin (10) at least to the upwind side ends of the heat transfer tubes (1), and which are inclined so as to be higher on the upstream side of the airflow direction than on the downstream side.

Description

Heat Exchanger, Refrigeration Cycle Device and Air Conditioner

[0001] The present disclosure relates to a fin-tube heat exchanger, a refrigeration cycle device including the heat exchanger, and an air conditioner.

[0002] Conventionally, a fin-tube heat exchanger including a plurality of plate-shaped fins and a plurality of flat heat transfer tubes is known. In this heat exchanger, the heat transfer tubes are inserted into notches formed in each of the fins arranged at predetermined pitch intervals, and arranged orthogonally to the fins. Air flows between the fins, thereby exchanging heat with the refrigerant flowing inside the heat transfer tubes.

[0003] A heat exchanger using flat tubes as heat transfer tubes, compared with a heat exchanger using circular tubes as heat transfer tubes, can not only expand the heat transfer area, but also reduce air draft resistance, so it is excellent in heat transfer performance. On the other hand, when the heat exchanger is used as an evaporator, condensed water tends to accumulate on the flat surfaces of the flat tubes, and frost formation will reduce the heat transfer performance.

[0004] Therefore, heat exchangers that improve the drainage performance of condensed water retained on flat surfaces have been proposed. For example, in the heat exchanger disclosed in Patent Document 1, on the surface of the fin, among the heat transfer portions located between vertically adjacent flat tubes, a bead-shaped water guide portion formed to protrude toward one surface side of the fin is provided near the upper flat surface of the flat tube.

[0005] Japanese Patent No. 6375897

[0006] However, in the above-mentioned conventional heat exchanger, the portion protruding to the windward side beyond the heat transfer portion of the fin is divided in the direction of gravity, so condensed water adhering to the windward side of the fin accumulates at the lower end of the protruding portion. As a result, the windward side of the fin freezes, which poses a problem that the heat transfer performance cannot be improved.

[0007] The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide a fin-tube heat exchanger that drains condensed water generated on the windward side of fins and secures heat transfer performance, as well as a refrigeration cycle device and an air conditioner including the heat exchanger.

[0008] The heat exchanger according to this disclosure comprises a plurality of heat transfer tubes arranged spaced apart in the direction of gravity and for circulating a refrigerant in a flow direction perpendicular to the direction of gravity, and a plurality of fins extending in the direction of gravity and arranged spaced apart in the flow direction and intersecting the plurality of heat transfer tubes, and is a heat exchanger that exchanges heat with air circulating in a ventilation direction perpendicular to the flow direction, wherein the fins are provided with a plurality of insertion holes for inserting each of the plurality of heat transfer tubes on the windward side in the ventilation direction, and windward projections that protrude further windward than the windward end of the heat transfer tube, and the windward projections have windward water guides that protrude in the flow direction, extend from the windward end of the fin to at least the windward end of the heat transfer tube, and are inclined such that the upstream side in the ventilation direction is higher than the downstream side.

[0009] According to this disclosure, condensation water adhering to the windward protrusions of fins that are separated in the direction of gravity can be easily drained by the windward water guide to the heat transfer tubes. This suppresses freezing of the windward protrusions of the fins and ensures heat transfer performance.

[0010] This is a schematic perspective view of a heat exchanger according to Embodiment 1. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 1, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. This is a schematic cross-sectional view showing the upwind water guide section of the heat exchanger according to Embodiment 1, enlarged from a part of the A-A section in Figure 2. This is a schematic cross-sectional view showing a modified example of the upwind water guide section of the heat exchanger according to Embodiment 1. This is a schematic cross-sectional view showing a modified example of the upwind water guide section of the heat exchanger according to Embodiment 1. This is a schematic cross-sectional view showing a modified example of the heat exchanger according to Embodiment 1. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 2, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 3, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 4, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. This is a schematic cross-sectional view showing a modified example of the upwind water guide section of the heat exchanger according to Embodiment 4. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 5, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 5, cut in a direction perpendicular to the ventilation direction. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 6, taken in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. This is a schematic cross-sectional view of the heat exchanger according to Embodiment 6, taken in a direction perpendicular to the ventilation direction. This is a refrigerant circuit diagram showing the schematic configuration of the refrigeration cycle device according to Embodiment 7.

[0011] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same reference numerals indicate the same or corresponding parts, and redundant explanations are omitted or simplified as appropriate. For the sake of clarity, each drawing includes mutually orthogonal x, y, and z directions. The x and y directions are horizontal, and the z direction is the direction of gravity. This disclosure is not limited to the following embodiments, and any modification of any component or any combination of embodiments and modifications is permitted without departing from the spirit of this disclosure.

[0012] Embodiment 1. A heat exchanger 100 according to Embodiment 1 will be described with reference to Figures 1 to 6. Figure 1 is a schematic perspective view of the heat exchanger according to Embodiment 1. Figure 2 is a schematic cross-sectional view of the heat exchanger according to Embodiment 1, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. Figure 3 is a schematic cross-sectional view showing the upwind water guide section of the heat exchanger according to Embodiment 1, enlarged from a part of the A-A section of Figure 2. Figure 4 is a schematic cross-sectional view showing a modified example of the upwind water guide section of the heat exchanger according to Embodiment 1. Figure 5 is a schematic cross-sectional view showing a modified example of the upwind water guide section of the heat exchanger according to Embodiment 1. Figure 6 is a schematic cross-sectional view showing a modified example of the heat exchanger according to Embodiment 1.

[0013] <Configuration of Heat Exchanger 100 According to Embodiment 1> As shown in Figure 1, the heat exchanger 100 according to this embodiment comprises a plurality of heat transfer tubes 1, a pair of headers 2, and a plurality of fins 10. The heat exchanger 100 is configured to exchange heat between a refrigerant flowing in the x-direction inside the heat transfer tubes 1 and air flowing outside the heat transfer tubes 1 in the y-direction. Hereinafter, in the y-direction, the upstream side in the airflow direction will be called the windward side, and the downstream side in the airflow direction will be called the leeward side.

[0014] Each of the multiple heat transfer tubes 1 extends in the x-direction and is arranged with spacing between them in the z-direction (direction of gravity). As shown in Figure 2, the heat transfer tubes 1 are flattened tubes with a unidirectional flattened surface, such as an oval shape, in the cross-sectional shape perpendicular to the x-direction, and the flattened surface of the heat transfer tubes 1 is aligned with the y-direction. Multiple refrigerant flow channels (not shown) are formed inside the heat transfer tubes 1 through which the refrigerant flows. The heat transfer tubes 1 are formed from, for example, aluminum or an aluminum alloy. Alternatively, the heat transfer tubes 1 may be made from clad materials such as aluminum, copper, or stainless steel.

[0015] A pair of headers 2 are connected to both ends of the heat transfer tubes 1 in the extension direction (x direction). One header 2 is provided with an inlet 2a through which refrigerant flows in, and the other header 2 is provided with an outlet 2b through which refrigerant flows out. The inlet 2a and outlet 2b are connected to the refrigerant piping that constitutes the refrigeration cycle device (see Figure 15), which will be described later. The refrigerant that flows into one header 2 from the inlet 2a is distributed to each heat transfer tube 1 and flows in the x direction, then merges in the other header 2 and flows out from the outlet 2b.

[0016] <Configuration of the fin 10 according to Embodiment 1> Each of the multiple fins 10 is formed into a plate shape. The fins 10 are stretched in the y and z directions and are arranged with spacing between them in the x direction. The fins 10 are formed using, for example, aluminum or an aluminum alloy.

[0017] As shown in Figure 2, the fin 10 is provided with insertion holes 11 cut out in a shape that follows the outer shape of the heat transfer tube 1, extending from one end on the windward side in the short direction (y direction) to the other end. Numerous insertion holes 11 are formed at predetermined intervals in the longitudinal direction (z direction) of the fin 10. When the heat transfer tubes 1 are inserted into these insertion holes 11, the heat transfer tubes 1 are arranged at predetermined intervals. When the heat transfer tubes 1 are inserted into the insertion holes 11, the straight line in the direction of gravity (z direction) passing through the windward end of the heat transfer tube 1 is the windward end line V1 of the heat transfer tube.

[0018] The fin 10 has a drainage region 12 on the leeward side of the insertion hole 11. The drainage region 12 is a region where the insertion hole 11 is not formed and the fin 10 is formed connected in the direction of gravity (z direction). The drainage region 12 is a region where condensation water adhering to the fin 10 is discharged in the direction of gravity. When the heat transfer tube 1 is inserted into the insertion hole 11, the straight line in the direction of gravity (z direction) passing through the leeward end of the heat transfer tube 1 is the leeward end line V2 of the heat transfer tube.

[0019] The fin 10 has an upwind projection 13 that protrudes approximately 5 mm in length upwind of the heat transfer tube's upwind end line V1. The upwind projection 13 has an upwind end 14 that extends approximately 1 mm to 2 mm downwind from the upwind tip in the direction of gravity. The upwind projection 13 is provided with an upwind water guide 20 that protrudes in the x direction. The upwind water guide 20 is located approximately 1 mm to 2 mm above the insertion hole 11 and is formed into a convex shape by press working on a part of the upwind projection 13. The upwind water guide 20 extends from the upwind end 14 to the heat transfer tube's upwind end line V1 in the upwind projection 13. The upwind water guide 20 is inclined in the y direction from the upwind side to the leeward side such that the upwind side is higher than the leeward side.

[0020] As shown in Figure 3, the cross-sectional shape of the upwind water intake section 20 is a mountain shape that slopes in the direction of gravity toward a convex portion that protrudes in the x direction. The cross-sectional shape of the upwind water intake section 20 may be a trapezoidal shape with ridges like a mountain shape, or it may be a semicircular shape without ridges.

[0021] In addition to being formed by press working, the upwind water guide section 20 may also be formed by cutting and raising the upper edge of the insertion hole 11 from the upwind end of the upwind projection 13 to the upwind end of the heat transfer tube 1, as shown in Figure 4. Thus, the method of forming the upwind water guide section 20 is not limited to press working.

[0022] Furthermore, as shown in Figure 5, the upwind water guide portion 20 may be provided not only on the upper side of the insertion hole 11 but also on the lower side. When the upwind water guide portion 20 is provided on the lower side of the insertion hole 11, the upwind water guide portion 20 on the lower side of the insertion hole 11 may have the same length, angle, and cross-sectional shape as the upwind water guide portion 20 on the upper side of the insertion hole 11, or it may have different characteristics. For example, the length of the upwind water guide portion 20 on the lower side of the insertion hole 11 may be formed to be longer than the length of the upwind water guide portion 20 on the upper side of the insertion hole 11. Moreover, only one upwind water guide portion 20 may be provided in the upwind projection portion 13, or there may be multiple upwind water guide portions, not limited to the two above and below the insertion hole 11.

[0023] In this embodiment, the heat transfer tube 1 is arranged perpendicular to the direction of gravity (z-direction). However, as shown in Figure 6, the heat transfer tubes 1a and 1b may be arranged with a downward slope from the windward side to the leeward side. Heat transfer tubes 1a and 1b refer to two heat transfer tubes that are adjacent vertically among a plurality of heat transfer tubes 1, with heat transfer tube 1b positioned below heat transfer tube 1a. When the heat transfer tubes are inclined, the opening of the insertion hole 11 is formed to follow the inclination of heat transfer tube 1a. The inclination angle θ of heat transfer tube 1a is set so that the windward end of heat transfer tube 1b and the leeward end of heat transfer tube 1a do not overlap when viewed from the y-direction. For example, if the distance between heat transfer tubes 1a and 1b is H [mm] and the width of heat transfer tube 1a is W [mm], the inclination angle θ should be set so that Wsinθ < H / 2.

[0024] <Effects of the Heat Exchanger 100 According to Embodiment 1> Next, the effects of the heat exchanger 100 according to Embodiment 1 will be explained. The air flowing into the heat exchanger 100 undergoes heat exchange with the refrigerant flowing through the heat transfer tubes 1. When the heat exchanger 100 is used as an evaporator, the ventilated air is cooled by the refrigerant absorbing heat. As the amount of saturated water vapor in the cooled air decreases, condensation occurs on the surface of the heat exchanger 100. The condensed water that forms on the windward projection 11 of the fins 10 flows down in the direction of gravity and collects on the upper surface of the windward water guide section 20. The condensed water that collects on the upper surface of the windward water guide section 20 flows along the slope of the windward water guide section 20 to the windward end of the heat transfer tubes 1 and is drained.

[0025] As described above, in the heat exchanger 100 according to Embodiment 1, condensation water generated on the windward projection 13 of the fin 10 collects in the windward water guide section 20 and flows along the slope of the windward water guide section 20. The condensation water that flows through the windward water guide section 20 then flows to the heat transfer tube 1 and is drained. As a result, condensation water does not accumulate on the windward projection 13, and freezing can be suppressed. This ensures the heat transfer performance of the heat exchanger 100.

[0026] Furthermore, the cross-sectional shape of the upwind water intake section 20 is a mountain shape that slopes in the direction of gravity toward a convex portion that protrudes in the x-direction. As a result, the condensation water collected in the upwind water intake section 20 flows toward the convex portion in the direction of gravity, thereby improving the drainage effect.

[0027] Even when the upwind water intake section 20 is formed by cutting and bending, the drainage effect of condensation water adhering to the upwind projection 13 can be obtained in the same way, suppressing freezing of the upwind projection 13 and ensuring the heat transfer performance of the heat exchanger 100.

[0028] Furthermore, a similar drainage effect can be obtained even when the upwind water guide section 20 is provided above and below the insertion hole 11. In this case, the upwind water guide section 20 improves the bending strength of the upwind projection 13, and the strength of the fin 10 is also improved. Moreover, if the lower upwind water guide section 20 is longer than the upper upwind water guide section 20, the strength of the fin 10 is improved, and the drainage performance of the upwind projection 13 can also be improved.

[0029] Furthermore, if the heat transfer tubes 1 are arranged with a downward slope from the windward side to the leeward side, the condensed water that flows down the windward water guide section 20 reaches the heat transfer tubes 1 and then flows down the upper side of the heat transfer tubes 1. As a result, the condensed water is drained without accumulating on the upper side of the heat transfer tubes 1. This further improves the heat transfer performance of the heat exchanger 100.

[0030] Embodiment 2. The heat exchanger 101 according to Embodiment 2 will be described with reference to Figure 7. Figure 7 is a schematic cross-sectional view of the heat exchanger according to Embodiment 2, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. In the following embodiments, the explanation of matters common to Embodiment 1 will be omitted, and unless otherwise specified, the configuration, operation and effects are the same as those of the heat exchanger 100 of Embodiment 1 described above.

[0031] As shown in Figure 7, the heat exchanger 101 according to this embodiment differs from the heat exchanger 100 according to Embodiment 1 in the length and arrangement of the upwind water guide section 20.

[0032] In this embodiment, the upwind water guide section 20 extends from the upwind end 14 of the upwind projection 13 to the downwind side of the upwind end line V1 of the heat transfer tube. In other words, the upwind water guide section 20 is formed to overlap with the upwind end of the heat transfer tube 1. The upwind water guide section 20 is inclined so that the upwind side is higher than the downwind side when viewed from the upwind side to the downwind side.

[0033] In the heat exchanger 101 according to this embodiment, condensation water generated on the windward projection 13 flows down in the direction of gravity and collects on the upper surface of the windward water guide 20. The condensation water collected on the upper surface of the windward water guide 20 flows along the slope of the windward water guide 20 and reaches the upper side of the heat transfer tube 1. The condensation water that reaches the upper side of the heat transfer tube 1 travels down to the leeward side of the heat transfer tube 1 and is drained. As a result, condensation water does not accumulate on the windward projection 13, and freezing can be suppressed. This ensures the heat transfer performance of the heat exchanger 101.

[0034] Furthermore, according to the heat exchanger 101 of this embodiment, since the upwind water guide section 20 extends downwind from the upwind end line V1 of the heat transfer tube, the bending strength of the upwind projection 13 is improved, and the strength of the fins 10 is also improved.

[0035] Embodiment 3. The heat exchanger 102 according to Embodiment 3 will be described with reference to Figure 8. Figure 8 is a schematic cross-sectional view of the heat exchanger according to Embodiment 3, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes.

[0036] As shown in Figure 8, the heat exchanger 102 according to this embodiment differs from the heat exchanger 100 according to Embodiment 1 in the length and arrangement of the upwind water guide section 20.

[0037] In this embodiment, the upwind water guide section 20 extends from the upwind end 14 of the upwind projection 13 to the downwind end line V2 of the heat transfer tube. The upwind water guide section 20 is inclined so that the upwind side is higher than the downwind side when viewed from the upwind side to the downwind side.

[0038] In the heat exchanger 102 according to this embodiment, condensation water generated on the windward projection 13 flows down in the direction of gravity and collects on the upper surface of the windward water guide 20. The condensation water collected on the upper surface of the windward water guide 20 flows along the slope of the windward water guide 20 to the leeward end line V2 of the heat transfer tube, reaches the drainage area 12 and is drained. As a result, condensation water does not accumulate on the windward projection 13, and freezing can be suppressed. Furthermore, since condensation water does not accumulate on the upper side of the heat transfer tube 1, the heat transfer performance of the heat exchanger 102 can be ensured.

[0039] Furthermore, the upwind water intake section 20 may extend downwind beyond the downwind end line V2 of the heat transfer tube. In this case, the bending strength of the drainage region 12 is further improved, and the strength of the fins 10 is also enhanced.

[0040] Embodiment 4. The heat exchanger 103 according to Embodiment 4 will be described with reference to Figures 9 and 10. Figure 9 is a schematic cross-sectional view of the heat exchanger according to Embodiment 4, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. Figure 10 is a schematic cross-sectional view showing a modified example of the upwind water guide section of the heat exchanger according to Embodiment 4.

[0041] As shown in Figures 9 and 10, the heat exchanger 103 according to this embodiment is provided with a downwind water guide section 21 compared to the heat exchangers according to Embodiments 1 to 3.

[0042] As shown in Figure 9, the downwind water conduit 21 protrudes in the x-direction and extends for a length of several millimeters from the downwind end line V2 of the heat transfer tube toward the drainage area 12. The downwind water conduit 21 is formed into a convex shape by press working on a part of the drainage area 12. The downwind water conduit 21 is inclined so that the upwind side is higher than the downwind side from the upwind side toward the downwind side. The cross-sectional shape of the downwind water conduit 21 is a mountain shape that slopes toward the direction of gravity toward the convex part that protrudes in the x-direction, similar to the upwind water conduit 20. The cross-sectional shape of the downwind water conduit 21 may be a trapezoidal shape with ridges like a mountain shape, or it may be a semicircular shape without ridges.

[0043] In the heat exchanger 103 according to this embodiment, condensation water generated on the upwind projection 13 flows down in the direction of gravity and collects on the upper surface of the upwind water guide 20. The condensation water collected on the upper surface of the upwind water guide 20 flows along the slope of the upwind water guide 20 and reaches the upper side of the heat transfer tube 1. The condensation water that reaches the upper side of the heat transfer tube 1 travels downwind to the downwind side of the heat transfer tube 1 and reaches the downwind water guide 21. The condensation water that reaches the downwind water guide 21 is drained into the drainage area 12 along the slope of the downwind water guide 21. As a result, condensation water does not accumulate on the upwind projection 13 and can be efficiently drained into the drainage area 12, thereby suppressing freezing of the upwind projection 13. This ensures the heat transfer performance of the heat exchanger 103.

[0044] Furthermore, according to the heat exchanger 103 of the present embodiment, the leeward water guide portion 21 improves the bending resistance of the drain region 12, and also achieves the effect of improving the strength of the fins 10.

[0045] As a modification, as shown in Fig. 10, when the windward water guide portion 20 extends to the heat transfer tube leeward end line V2, it may be joined to the leeward water guide portion 21. In this case, the windward water guide portion 20 and the leeward water guide portion 21 may be integrally formed.

[0046] Embodiment 5. The heat exchanger 104 according to Embodiment 5 will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a schematic cross-sectional view of the heat exchanger according to Embodiment 5, taken along a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. Fig. 12 is a schematic cross-sectional view of the heat exchanger according to Embodiment 5, taken along a direction perpendicular to the ventilation direction.

[0047] As shown in Fig. 11 and Fig. 12, the heat exchanger 104 according to the present embodiment is provided with slits 30 compared to the heat exchangers according to Embodiments 1 to 4.

[0048] The slits 30 are provided to promote heat conduction between the air passing through the heat exchanger 104 and the fins 1. As shown in Fig. 11, the slits 30 are provided in the intermediate region 15 between vertically adjacent heat transfer tubes 1, and are formed by cutting a part of the fins 10. Each slit 30 extends in the direction of gravity from below the upper heat transfer tube 1 to above the lower heat transfer tube 1, and a plurality of slits 30 are arranged in parallel in the y-direction. When the windward water guide portions 20 are provided above and below the insertion hole 11, the slit 30 is provided so as to extend in the direction of gravity from below the windward water guide portion 20 provided below the insertion hole 11 to above the windward water guide portion 20 provided above the insertion hole 11.

[0049] As shown in Fig. 12, the longitudinal direction (z-direction) of the slit 30 is separated from the fin 10, and the transverse direction (y-direction) of the slit 30 is connected to the fin 10. The transverse direction (y-direction) of the slit 30 is inclined from the windward side toward the leeward side such that the windward side is located higher than the leeward side.

[0050] The shape and position of the slits are not limited to those shown. For example, the slits 30 may extend from the windward side to the leeward side, and multiple slits 30 may be arranged in parallel in the z direction. In this case, the longitudinal direction (y direction) of the slits 30 is connected to the fin 10, and the short direction (z direction) is separated from the fin 10. The longitudinal direction (y direction) of the slits 30 is inclined such that the windward side is higher than the leeward side when viewed from the windward side to the leeward side.

[0051] Furthermore, there are no particular limitations on the number or size of the slits 30. The slits 30 do not need to be of the same size; they may all be different.

[0052] The upwind water guide section 20 according to this embodiment is provided above and below the insertion hole 11 and extends from the upwind end 14 to the downwind side beyond the upwind end line V1 of the heat transfer tube. The upwind water guide section 20 may be provided only above the insertion hole 11, or it may extend to the downwind side beyond the downwind end line V2 of the heat transfer tube. A downwind water guide section 21 may also be provided.

[0053] In the heat exchanger 104 according to this embodiment, condensation water generated in the intermediate region 15 and condensation water induced from the upwind water guide section 20 adhere to the upper or lower edge of the slit 30. The condensation water adhering to the slit 30 flows down along the slope of the slit 30. The flowing condensation water reaches the upper side of the heat transfer tube 1. The condensation water that reaches the upper side of the heat transfer tube 1 flows downwind of the heat transfer tube 1 and is drained. As a result, the condensation water generated in the intermediate region 15 is drained without accumulating in the slit 30, thus suppressing freezing of the intermediate region 15. Therefore, the heat transfer performance of the heat exchanger 104 can be better ensured.

[0054] Embodiment 6. The heat exchanger 105 according to Embodiment 6 will be described with reference to Figures 13 and 14. Figure 13 is a schematic cross-sectional view of the heat exchanger according to Embodiment 6, cut in a direction perpendicular to the refrigerant flow direction of the heat transfer tubes. Figure 14 is a schematic cross-sectional view of the heat exchanger according to Embodiment 6, cut in a direction perpendicular to the ventilation direction.

[0055] As shown in Figures 13 and 14, the heat exchanger 105 according to this embodiment has a different slit shape from the heat exchanger according to Embodiment 5.

[0056] As shown in Figure 13, the slit 30 in this embodiment is provided with an upper slit 30a located above the intermediate region 15 and a lower slit 30b located below the intermediate region 15, arranged alternately in the y-direction. The upper slit 30a extends in the direction of gravity from below the heat transfer tube 1 to near the center of the intermediate region 15 in the z-direction. The lower slit 30b extends in the direction of gravity from near the center of the intermediate region 15 in the z-direction to above the adjacent lower heat transfer tube 1. The longitudinal direction (z-direction) of the upper slit 30a and the lower slit 30b is separated from the fin 10, while the short direction (y-direction) of the upper slit 30a and the lower slit 30b is connected to the fin 10. The short direction (y-direction) of the upper slit 30a and the lower slit 30b is inclined from the windward side to the leeward side, with the windward side being higher than the leeward side. As shown in Figure 14, the upper slit 30a and the lower slit 30b are arranged such that, in the y-direction, there are portions where adjacent slits do not overlap. The upper slit 30a is provided in the front row on the windward side of the intermediate region 15.

[0057] The upwind water guide section 20 according to this embodiment is provided above and below the insertion hole 11 and extends from the upwind end 14 to the downwind side beyond the upwind end line V1 of the heat transfer tube. The upwind water guide section 20 may be provided only above the insertion hole 11, or it may extend to the downwind side beyond the downwind end line V2 of the heat transfer tube. A downwind water guide section 21 may also be provided.

[0058] In the heat exchanger 105 according to this embodiment, condensation water guided from the upwind water guide section 20 provided above the insertion hole 11 can reach the upper side of the heat transfer tube 1 without coming into contact with the upper slit 30a. That is, since condensation water guided from the upwind water guide section 20 provided above the insertion hole 11 does not accumulate on the lower edge of the upper slit 30a, freezing of the upper slit 30a can be suppressed. Furthermore, even if the upper slit 30a in the front row on the upwind side, which is prone to frost formation, were to freeze, the adjacent lower slit 30b has a portion that does not overlap with the upper slit 30a in the y direction, allowing air to circulate. As a result, the heat transfer performance of the heat exchanger 105 can be further ensured.

[0059] Embodiment 7. Embodiment 7 relates to a refrigeration cycle device 200 such as an air conditioner equipped with a heat exchanger according to Embodiments 1 to 6.

[0060] Using Figure 15, the configuration of the refrigeration cycle device 200 according to this embodiment when applied to an air conditioner will be explained. Figure 15 is a refrigerant circuit diagram showing the schematic configuration of the refrigeration cycle device 200 according to this embodiment. The refrigeration cycle device 200 comprises an outdoor unit 201 installed outdoors and an indoor unit 202 installed in the room to be air-conditioned. The outdoor unit 201 comprises a compressor 203, a four-way valve 204, an expansion valve 205, an outdoor heat exchanger 210, and an outdoor fan 210a. The indoor unit 202 comprises an indoor heat exchanger 220 and an indoor fan 220a. The refrigeration cycle device 200 comprises a refrigerant circuit in which the compressor 203, the four-way valve 204, the outdoor heat exchanger 210, the expansion valve 205, and the indoor heat exchanger 220 are sequentially connected by piping.

[0061] The refrigerant used in the refrigeration cycle device 200 according to this embodiment may be a single refrigerant such as difluoromethane (R32), 1,1,1,2-tetrafluoroethane (R134a), pentafluoroethane (R125), tetrafluoropropene (R1234yf), 1,3,3,3-tetrafluoro-1-propene (R1234ze), trans-1,2-difluoroethylene (R1132(E)), trifluoroethylene (R1123), propane (R290), propylene (R1270), ethane (R170), butane (R600), isobutane (R600a), ammonia (NH3; R717), carbon dioxide (CO2; R744), or a mixed refrigerant containing at least one of these. Alternatively, other types of refrigerants may also be used.

[0062] The compressor 203 draws in a low-temperature, low-pressure refrigerant, compresses the drawn-in refrigerant to increase its pressure and temperature, and then discharges it. The compressor 203 can be, for example, a rotary compressor, a scroll compressor, or a reciprocating compressor. A multi-stage compressor that divides the compression process into two or more stages may also be used. In addition to an inverter compressor that variably controls the operating frequency with an inverter, a constant-speed compressor that operates at a constant operating frequency may also be used.

[0063] The four-way valve 204 switches the flow of refrigerant discharged from the compressor 203. When the refrigeration cycle unit 200 is in cooling operation, the refrigerant discharged from the compressor 203 flows into the outdoor heat exchanger 210, and when it is in heating operation, the refrigerant discharged from the compressor 203 flows into the indoor heat exchanger 220.

[0064] The expansion valve 205 is installed between the outdoor heat exchanger 210 and the indoor heat exchanger 220. The expansion valve 205 reduces the pressure of the liquid refrigerant condensed in the condenser to create a low-pressure gas-liquid two-phase refrigerant. This condenser is the outdoor heat exchanger 210 in the case of cooling operation and the indoor heat exchanger 220 in the case of heating operation. The expansion valve 205 can be, for example, an electronic expansion valve with adjustable opening degree, a thermostatic expansion valve, etc. A capillary tube or the like with an inability to adjust opening degree may also be used for the expansion valve 205.

[0065] The outdoor heat exchanger 210 and the indoor heat exchanger 220 exchange heat between the circulating refrigerant and the air blown by the outdoor fan 210a or the indoor fan 220a. One refrigerant inlet / outlet of the outdoor heat exchanger 210 is connected to a four-way valve 204, and the other refrigerant inlet / outlet is connected to an expansion valve 205. One refrigerant inlet / outlet of the indoor heat exchanger 220 is connected to an expansion valve 205, and the other refrigerant inlet / outlet is connected to a four-way valve 204. The outdoor heat exchanger 210 and the indoor heat exchanger 220 are, for example, fin-tube type heat exchangers having circular or flattened heat transfer tubes through which the refrigerant flows, and fins attached to the heat transfer tubes. When the refrigeration cycle device 200 is in cooling operation, the outdoor heat exchanger 210 operates as a condenser, and the indoor heat exchanger 220 operates as an evaporator. On the other hand, when the refrigeration cycle device 220 is operating in heating mode, the outdoor heat exchanger 210 operates as an evaporator and the indoor heat exchanger 220 operates as a condenser. The refrigeration cycle device 200 uses a heat exchanger according to any of Embodiments 1 to 6 in at least one of the outdoor heat exchanger 210 and the indoor heat exchanger 220.

[0066] When the refrigeration cycle unit 200 is operating in cooling mode, the four-way valve 204 is connected to the dashed line side. The high-temperature, high-pressure gaseous refrigerant compressed by the compressor 203 flows into the outdoor heat exchanger 210, where it exchanges heat with the surrounding air and condenses to become a low-temperature, high-pressure liquid refrigerant. The liquid refrigerant flows into the expansion valve 205, where it is depressurized to become a low-temperature, low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant flows into the indoor heat exchanger 220, where it exchanges heat with the surrounding air. The refrigerant evaporates to become a low-temperature, low-pressure gaseous refrigerant, which cools the surrounding air and returns to the compressor 203 through the four-way valve 204.

[0067] When the refrigeration cycle unit 200 is in heating operation, the four-way valve 204 is connected to the solid line side. When switching from cooling operation to heating operation, the outdoor heat exchanger 210 changes from a condenser to an evaporator, and the indoor heat exchanger 220 changes from an evaporator to a condenser. The high-temperature, high-pressure gaseous refrigerant compressed by the compressor 203 flows into the indoor heat exchanger 220, exchanges heat with the surrounding air, and releases heat to warm the surrounding air. The gaseous refrigerant condenses to become a low-temperature, high-pressure liquid refrigerant and flows into the expansion valve 205, where it is depressurized to become a low-temperature, low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant flows into the outdoor heat exchanger 210 and exchanges heat with the surrounding air. The refrigerant evaporates to become a low-temperature, low-pressure gaseous refrigerant, which cools the surrounding air and returns to the compressor 203 through the four-way valve 204.

[0068] The refrigeration cycle device 200 with the above configuration, by including a heat exchanger according to any of Embodiments 1 to 6, can suppress freezing of the upwind projection 13 when operating as an evaporator, and ensure the heat transfer performance of the outdoor heat exchanger 210 or the indoor heat exchanger 220. This improves the operating efficiency of the refrigeration cycle device 200.

[0069] In particular, in the outdoor heat exchanger 210, since heating operation is performed at low outside air temperatures, there is a possibility that condensation water remaining on the windward projection 13 may freeze prematurely. If frost forms on the outdoor heat exchanger 210, the heating capacity may decrease, but with the refrigeration cycle device 200 according to this embodiment, by equipping the outdoor heat exchanger 210 with a heat exchanger from any of Embodiments 1 to 6, the decrease in heating capacity can be suppressed even during low outside air operation.

[0070] Furthermore, the refrigeration cycle device 200 according to this embodiment can be applied to applications other than air conditioners, and can be used as a refrigeration cycle device for refrigerators, freezers, refrigerated display cases, vending machines, refrigeration equipment, and water heaters.

[0071] 1 Heat transfer tube, 2 Header, 10 Fin, 11 Insertion hole, 12 Drainage area, 13 Upwind projection, 14 Upwind end, 15 Intermediate area, 20 Upwind water conduit, 21 Downwind water conduit, 30 Slit, 100, 101, 102, 103, 104, 105 Heat exchanger, 200 Refrigeration cycle device, 201 Outdoor unit, 202 Indoor unit, 203 Compressor, 204 Four-way valve, 205 Expansion valve, 210 Outdoor heat exchanger, 210a Outdoor fan, 220 Indoor heat exchanger, 220a Indoor fan.

Claims

1. A heat exchanger having a plurality of heat transfer tubes arranged spaced apart in the direction of gravity and through which a refrigerant flows in a flow direction perpendicular to the direction of gravity, and a plurality of fins extending in the direction of gravity and arranged spaced apart in the flow direction and intersecting the plurality of heat transfer tubes, wherein the heat exchanger exchanges heat with air flowing in a ventilation direction perpendicular to the flow direction, wherein the fins are provided with a plurality of insertion holes for inserting each of the plurality of heat transfer tubes on the windward side in the ventilation direction, and windward protrusions that protrude further windward than the windward end of the heat transfer tube, and the windward protrusions have a windward water guide section that protrudes in the flow direction, extends from the windward end of the fin to at least the windward end of the heat transfer tube, and is inclined such that the upstream side in the ventilation direction is higher than the downstream side.

2. The heat exchanger according to claim 1, characterized in that the upwind water guide extends from the upwind end of the fin so as to overlap with the upwind end of the heat transfer tube.

3. The heat exchanger according to claim 1 or 2, characterized in that the upwind water intake section extends from the upwind end of the fin to at least the downwind end of the heat transfer tube.

4. The refrigeration cycle apparatus according to any one of claims 1 to 3, further comprising a downwind water guide section on the leeward side of the fin, which protrudes in the flow direction, extends further downstream from the leeward end of the heat transfer tube, and is inclined such that the upstream side in the ventilation direction is higher than the downstream side.

5. The heat exchanger according to any one of claims 1 to 4, wherein the fin has one or more slit portions that extend in the direction of gravity and are cut up in the direction of airflow between the plurality of insertion holes, and the lower edge of the slit portion is inclined such that the upstream side in the airflow direction is higher than the downstream side.

6. The heat exchanger according to claim 5, wherein the lower edge of the slit portion is positioned above the upwind water intake portion, and the slit portion is positioned such that it does not overlap with adjacent slit portions in the direction of airflow.

7. The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the heat transfer tubes are arranged inclined such that the upstream side in the ventilation direction is higher than the downstream side.

8. The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein the upwind water intake section is inclined in the direction of gravity toward a protrusion that protrudes in the flow direction.

9. A refrigeration cycle apparatus comprising a heat exchanger according to any one of claims 1 to 8.

10. An air conditioner equipped with the refrigeration cycle device described in claim 9.

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