JP2009168317A - Heat exchanger and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat transferring performance without significantly increasing ventilation resistance. <P>SOLUTION: The air conditioner is equipped with a plurality of fins 30 provided in parallel with predetermined spaces for distributing heat exchanging air along the spaces, heat transfer tubes 40 disposed adjacent to each other penetrating through the fins 30 in the direction orthogonal to a distributing direction F of the heat exchanging air in the fins 30 and introducing cooling medium, and slits 33 provided between the adjacent heat transfer tubes 40. The slits 33 are provided at least in a range of a center line C connecting an windward side edge 31a of the fins 30 and centers of respective heat transfer tubes 40. The width of the distributing direction of the heat exchanging air is formed to be half or more of an outer diameter D of the heat transfer tube 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat exchanger and an air conditioner including the heat exchanger, and more particularly to a shape of a cut and raised formed in fins constituting the heat exchanger.

  For example, a heat exchanger is provided as a component of a refrigeration cycle in an air conditioner. When the air conditioner is composed of an indoor unit and an outdoor unit, a heat exchanger is required for any of the units. These heat exchangers are arranged side by side with a predetermined gap, and are provided with a plurality of fins that circulate heat exchange air along the gap, and through these fins. A so-called fin tube type composed of a heat transfer tube for conducting a medium) is often used.

  And in order to improve the heat exchange efficiency in a heat exchanger, it has become a recent tendency to cut and raise the fins. Since the plate thickness of the fin is extremely thin, for example, the die is die-cut by press working, and the above-described raising is simultaneously processed. This cut-and-raised part is provided between the heat transfer tubes provided adjacent to each other in a direction orthogonal to the flow direction of the heat exchange air.

  As described above, in a heat exchanger such as an air conditioner, heat exchange efficiency has been improved by providing a large number of cuts on the fins. Various ideas have been made for the cut and raised portion. For example, it is known that the cut-and-raised width is shorter for the airflow downstream side heat transfer tube and provided with a cut so that the downstream side heat transfer tube has a larger number (for example, see Patent Document 1).

Moreover, what made the width | variety of the cut and raised on the windward side wider than the width of the cut and raised side on the leeward side is also known (for example, refer patent document 2). Furthermore, what formed the width | variety of cutting and raising to 1 / 4-1 / 3 of the outer diameter of a fin collar is known (for example, refer patent document 3).
JP-A 63-003181 JP 2001-133179 A JP 2003-035497 A

  In the heat exchanger described above, sufficient heat transfer performance is not necessarily obtained, and further improvement in heat transfer performance is desired.

  Accordingly, an object of the present invention is to provide a heat exchanger that can further improve heat transfer performance while suppressing an increase in ventilation resistance, and an air conditioner including the heat exchanger.

  In order to solve the above problems and achieve the object, the heat exchanger and the air conditioner of the present invention are configured as follows.

(1) A plurality of fins that are arranged side by side with predetermined gaps and that allow heat exchange air to flow along these gaps, and fins in a direction perpendicular to the flow direction of heat exchange air in each fin. A heat transfer pipe which is adjacently penetrated and allows a heat exchange medium to pass through, and a notch provided between the adjacent heat transfer pipes, wherein the notch is at least the windward edge of the fin And in the range between the center lines connecting the centers of the heat transfer tubes, the width of the heat exchange air in the flow direction is formed to be 1/2 or more of the outer diameter of the heat transfer tubes.

(2) In an air conditioner including a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger, at least one of the outdoor heat exchanger and the indoor heat exchanger has a predetermined gap. The plurality of fins that are arranged side by side and circulate the heat exchange air along these gaps, and are adjacent to each other through the fins in a direction perpendicular to the direction of the heat exchange air flow in each fin. A heat transfer tube for conducting a heat exchange medium; and a cut-and-raised portion provided between the adjacent heat transfer tubes, wherein the cut-and-lift is at least between the windward edge of the fin and the centers of the heat transfer tubes. The width of the heat exchange air in the flow direction is formed to be 1/2 or more of the outer diameter of the heat transfer tube.

  According to the present invention, heat transfer performance can be further improved while suppressing an increase in ventilation resistance.

  FIG. 1 is an explanatory view showing a configuration of a heat exchanger 20 and an air conditioner 10 incorporating the heat exchanger 20 according to an embodiment of the present invention, and FIG. 2A is a view of fins 30 constituting the heat exchanger 20. FIG. 2B is a side view, and FIG. 2C is a partial perspective view of the heat exchanger 20. In FIG. 2B, only one fin 30 is shown for convenience of explanation.

  The air conditioner 10 includes a compressor 12, a four-way valve 13, an outdoor heat exchanger 14, an expansion valve 15, a first indoor heat exchanger 16, a dehumidifying throttle device 17, and a second indoor heat through a refrigerant pipe 11. The exchanger 18, the four-way valve 13, and the compressor 12 are connected in this order. In FIG. 1, reference numeral 14a denotes a blower fan, and 16a denotes a cross-flow fan.

The heat exchanger 20 of the present invention constituting at least one of the outdoor heat exchanger 14 and the indoor heat exchanger (the first indoor heat exchanger 16 and the second indoor heat exchanger 18) is shown in FIG. 2A. 2B and 2C, it is a fin tube type in which a heat transfer tube 40 is provided through a large number of fins 30 arranged side by side with a narrow gap. The fin 30 has a vertically long strip shape, and the heat transfer tubes 40 in which the refrigerant (heat exchange medium) flows are penetrated at a predetermined pitch in the vertical direction. The heat transfer tubes 40 are provided in two rows in the flow direction F of the heat exchange air in the fins 30. In addition, the fin 30 may be divided | segmented for every row | line | column of the heat exchanger tube 40, and the heat exchanger tube may be provided in 1 row or 3 rows or more.

  The fin 30 includes a plate-like base 31, heat transfer tube insertion holes 32 provided in the base 31 at a predetermined pitch, and slits (cuts) 33 and 34 provided between the heat transfer tube insertion holes 32. , 33 ′ and 34 ′. The heat transfer tubes 40 are disposed through the fins 30 in a direction orthogonal to the heat exchange air flow direction F in the fins 30. The inner diameter dimension of the heat transfer tube insertion hole 32 is initially slightly larger than the outer diameter dimension of the heat transfer tube 40, and the heat transfer tube 40 penetrates the heat transfer tube insertion hole 32 to expand the heat transfer tube 40. As a result, the heat transfer tubes 40 are fitted into the fins 30 in a firm state.

  The slits 33, 34 and 33 ′, 34 ′ are arranged side by side with a predetermined gap along the direction in which the heat exchange air flows. The slits 33, 34, 33 ′ and 34 ′ are all formed so that the longitudinal direction thereof is perpendicular to the direction in which the heat exchange air flows, and project only in the same direction with respect to the base 31. Has been.

  Of the slits provided between the windward first row heat transfer tubes 40, the windward side slit 33 is a center connecting at least the windward edge 31 a of the fin 30 and the centers of the heat transfer tubes 40 in the first row. It is provided in the range between the lines C (windward side), and the width L in the flow direction F of the heat exchange air is formed to be 1/2 or more of the outer diameter D of the heat transfer tube 40. In addition, the slit 33 is preferably provided so that the end portion 33a on the leeward side coincides with the center line C connecting the centers of the heat transfer tubes 40, and the end portion 33b on the windward side is on the windward side of each heat transfer tube 40. Further, the rising portion 33 c is formed in a curved shape along the outer peripheral surface of the heat transfer tube 40. Of the slits provided between the first row of heat transfer tubes 40 on the windward side, the slit 34 on the leeward side similarly has a rising portion 34c. Thereby, the distance between the slits 33 and 34 and the heat transfer tube 40 is kept constant. Since the slit 33 is installed on the windward side from the center of the heat transfer tube 40, if the rising portion 33c is formed in a straight line, the slit area is reduced. By forming the rising portion 33c from a curve so as to keep the same distance as the heat transfer 40 tube, the rising area can be increased and the air flow can be made to follow the heat transfer tube 40, and the heat transfer performance is further improved.

 Of the slits provided between the second row of heat transfer tubes 40 on the leeward side, the slit 33 'on the leeward side is the center Y of the first row of fins 30 and the center Y of the second row of heat transfer tubes 40 and the second row. It is provided in a range between the center lines connecting the centers of the heat transfer tubes 40 (windward side), and the width L in the flow direction F of the heat exchange air is formed to be 1/2 or more of the outer diameter D of the heat transfer tubes 40. . Further, the slit 33 ′ is preferably provided so that the leeward side end portion 33 a coincides with the center line connecting the centers of the heat transfer tubes 40.

  Here, the reason for the shape of the fin 30 will be described. In general, the slit improves the heat transfer performance by stirring the flow of the heat exchange air, so the heat transfer performance improves as the number increases. However, since the ventilation resistance increases in proportion to the number, the heat transfer amount does not necessarily increase as the number increases.

  FIG. 3 shows the relationship between the number of slits, the heat transfer coefficient, and the ventilation resistance. As the number of slits increases, the heat transfer coefficient and ventilation resistance increase, but the increase in heat transfer coefficient is smaller than the increase in ventilation resistance. It can be seen from this that even if the number of slits is excessively increased, the performance cannot be improved by increasing the ventilation resistance.

  4A, 4B, FIGS. 5A, 5B, and 6A, 6B show the magnitude of pressure loss on the isosurfaces of the portions with high heat transfer calculated from the analysis in various fins. The shade of color in the figure indicates the magnitude of pressure loss. Therefore, the light colored part is the part where the pressure loss is small.

  4A and 4B, the heat transfer is high from the tip 51a of the base 51 to the vicinity of the center line between the heat transfer tube insertion holes 52 (two-dot chain line Q). This is presumed to be due to contraction of the heat transfer tube. The tip 51a stirs the heat exchange air flow and thus has high heat transfer but high ventilation resistance. It can also be seen that the portion with higher heat transfer is separated from the vicinity of the center of the heat transfer tube insertion hole 52 (two-dot chain line S: the darker portion is away from the heat transfer tube).

  5A and 5B, the base 61 is provided with two slits 63. In this case, although the peeling around the heat transfer tube is improved, it can be seen that the portion of the flat fin 50 where the heat transfer due to the contracted flow is high is eliminated by the stirring of the heat exchange air flow at the tip of the slit 53. The same applies to the fin 70 shown in FIGS. 6A and 6B. 6A and 6B, reference numeral 71 denotes a base, and 73 denotes three slits.

  From these results, in order to maintain an efficient part with a contracted flow (a part with a small pressure loss and a high heat transfer coefficient) seen in the flat fin 50, the air flow is disturbed by the tip of the fin. It is necessary to reduce as much as possible. At the same time, in order to improve the peeling around the heat transfer tube seen in the flat fin 50, it is necessary to provide a cut and raised on the windward side from the center of the heat transfer tube.

  Therefore, the center between the heat transfer tubes 40 that is the end of the heat transfer efficiency good portion accompanied by the contracted flow (center line C connecting the centers of the heat transfer tubes 40 adjacent to each other in the direction orthogonal to the flow direction F of the heat exchange air) Is provided with an end portion 33a on the leeward side of the slit 33, an end portion 33b on the leeward side before the contraction starts (upward side of the heat transfer tube 40), and the width of the slit 33 is increased. By setting it to D / 2 or more, heat transfer can be more efficiently promoted. However, even if the width of the slit 33 is set to D / 2 or more and the slit 33 is provided in the range between the center line C connecting the centers of the heat transfer tubes 40 from the windward side edge 31a of the fin 30, the same effect can be obtained. .

  Moreover, since heat transfer is small on the leeward side from the center line C between the heat transfer tubes 40, it is preferable to provide slits at predetermined intervals. However, it is desirable to install only one slit 34 in order to reduce the ventilation resistance. FIG. 7B shows the analysis result of the embodiment of the present invention shown in FIG. 7A. As is apparent from FIG. 7B, the high heat transfer portion of the present invention is greatly expanded as compared with those shown in FIGS. 5A and 5B and FIGS. 6A and 6B.

  The air conditioner 10 configured as described above operates as follows. That is, during the cooling / dehumidifying operation, the compressor 12 is operated and the refrigerant flows along the solid line arrow K in FIG. The high-temperature and high-pressure refrigerant vapor exiting the compressor 12 passes through the four-way valve 13 and flows into the outdoor heat exchanger 14, where heat is taken away by the outside air, and condensed and liquefied. The high-pressure liquid refrigerant that has exited the outdoor heat exchanger 14 flows into the expansion valve 15, is depressurized, becomes a low-pressure gas-liquid two-phase refrigerant, and flows into the first indoor heat exchanger 16. Furthermore, it flows into the 2nd indoor side heat exchanger 18 through the dehumidification throttle apparatus 17, and cold air blows off indoors in the crossflow fan 16a. While flowing through the heat transfer tubes 40 of the first indoor heat exchanger 16 and the second indoor heat exchanger 18, it is heated by the indoor air, and most of the low-pressure liquid refrigerant becomes steam and passes through the four-way valve 13. Then, it is sucked into the compressor 12 again.

  On the other hand, during the heating operation, the refrigerant flows along the broken line arrows in FIG. The high-temperature and high-pressure refrigerant vapor that exits the compressor 12 passes through the four-way valve 13 and flows into the second indoor heat exchanger 18. Further, the air flows into the first indoor heat exchanger 16 through the dehumidifying throttle device 17. The refrigerant that has flowed into the heat transfer tubes 40 of the second indoor heat exchanger 18 and the first indoor heat exchanger 16 is cooled by the indoor air, and is condensed and liquefied. The high-pressure liquid refrigerant that has exited the first indoor heat exchanger 16 flows into the expansion valve 15 and is depressurized, becomes a low-pressure gas-liquid two-phase refrigerant, and flows into the outdoor heat exchanger 14 that operates as an evaporator. This low-pressure gas-liquid two-phase refrigerant takes heat from the outside air in the outdoor heat exchanger 14 and evaporates to become low-pressure vapor refrigerant and flows out of the outdoor heat exchanger 14. This low-pressure vapor refrigerant passes through the four-way valve 13 and is sucked into the compressor 12 again.

  In such an operation, in the heat exchanger 20 incorporated in the outdoor heat exchanger 14, the first indoor heat exchanger 16, and the second indoor heat exchanger 18, heat exchange is performed as follows. Is done.

  While the refrigerant flows from the refrigerant pipe 11 into the heat transfer tube 40, the heat exchange air passes through the heat exchanger 20, whereby heat exchange is performed between the heat exchange air and the fins 30. As described above, the heat exchange air is efficiently transferred in the slit 33. Furthermore, since only one slit 34 is installed on the leeward side of the slit 33, the air flow resistance is not increased extremely, and heat transfer by the slit 34 is further performed. Heat transfer performance can be improved without significantly increasing ventilation resistance.

  As described above, in the heat exchanger 20 according to the present embodiment and the air conditioner 10 in which the heat exchanger 20 is incorporated, heat transfer performance can be improved without significantly increasing the ventilation resistance. In the air conditioner of the present invention, the heat exchanger 20 of the present invention may be applied to both the indoor side heat exchanger and the outdoor side heat exchanger, but either one, for example, the indoor side heat exchange It may be applied only to the vessel.

  FIG. 8 is a plan view showing a fin 30A according to a modification of the fin 30 constituting the heat exchanger 20 according to the above-described embodiment. In FIG. 8, the same functional parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fin 30 </ b> A, slits 35 and 36 are provided instead of the slits 33 and 34. In the slits 35 and 36, rising portions 35c and 36c are formed in a straight line. When formed in this way, the heat transfer performance is slightly reduced, but the processing can be simplified.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

Explanatory drawing which shows the structure of the heat exchanger which concerns on one embodiment of this invention, and the air conditioner incorporating this heat exchanger. The top view which shows the principal part of the fin integrated in the same heat exchanger. The side view which shows the same fin and a heat exchanger tube. The partial perspective view of the heat exchanger. The graph which shows the relationship between the number of slits, a heat transfer rate, and ventilation resistance. The perspective view which shows the principal part of the fin as a comparative example. Explanatory drawing which represented the magnitude of pressure loss on the isosurface of the part with high heat transfer in the principal part of the fin. The perspective view which shows the principal part of the fin as a comparative example. Explanatory drawing which represented the magnitude of pressure loss on the isosurface of the part with high heat transfer in the principal part of the fin. The perspective view which shows the principal part of the fin as a comparative example. Explanatory drawing which represented the magnitude of pressure loss on the isosurface of the part with high heat transfer in the principal part of the fin. The perspective view which shows the principal part of the fin integrated in the heat exchanger which concerns on this Embodiment. Explanatory drawing which represented the magnitude of pressure loss on the isosurface of the part with high heat transfer in the principal part of the fin. The top view which shows the modification of this Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Air conditioner, 20 ... Heat exchanger, 30 ... Fin, 31 ... Base, 32 ... Heat transfer tube insertion hole, 33-36 ... Slit, 40 ... Heat transfer tube.

Claims (3)

A plurality of fins that are arranged side by side with a predetermined gap and that circulate heat exchange air along these gaps, and the fins pass through the fins in a direction perpendicular to the direction of flow of the heat exchange air in each fin. A heat transfer tube that is adjacent and conducts a heat exchange medium therein, and a cut and raised provided between the adjacent heat transfer tubes;
The cut-and-raised portion is provided at least in a range between the center lines connecting the windward side edge of the fin and the centers of the heat transfer tubes, and the width in the flow direction of the heat exchange air is 1 of the outer diameter of the heat transfer tubes. / A heat exchanger characterized by being formed to 2 or more.   The cut-and-raised state is that the leeward side edge portion is provided so as to coincide with the center line connecting the centers of the heat transfer tubes, and the rising portion is formed in a curved shape along the outer peripheral surface of the heat transfer tube. The heat exchanger according to claim 1, wherein In an air conditioner equipped with a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger,
At least one of the outdoor heat exchanger and the indoor heat exchanger is:
A plurality of fins that are arranged side by side with a predetermined gap and that circulate heat exchange air along these gaps, and the fins pass through the fins in a direction perpendicular to the direction of flow of the heat exchange air in each fin. A heat transfer tube that is adjacent and conducts a heat exchange medium therein, and a cut and raised provided between the adjacent heat transfer tubes;
The cut-and-raised portion is provided at least in a range between the center lines connecting the windward side edge of the fin and the centers of the heat transfer tubes, and the width in the flow direction of the heat exchange air is 1 of the outer diameter of the heat transfer tubes. / An air conditioner characterized by being formed to 2 or more.

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