JP2009092316A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize a frost formation state and to extend a time of clogging by frost in a parallel flow type heat exchanger. <P>SOLUTION: This heat exchanger 1 comprises horizontal header pipes 2, 3 disposed in parallel with each other at an interval in the vertical direction, a plurality of vertical flat tubes 4 disposed at intervals in the horizontal direction between the header pipes 2, 3 in a state that refrigerant passages 5 inside thereof are respectively communicated with the inside of the header pipes, and corrugated fins 6 disposed among the flat tubes 4. The corrugated fins 6 are divided into windward-side corrugated fins 6U and leeward-side corrugated fins 6D, and a heat exchanging capacity of the leeward-side corrugated fins 6D is higher than that of the windward-side corrugated fins 6U. The heat exchanging capacities are differentiated by making a crest-trough pitch P2 of the leeward-side corrugated fin 6D smaller than a crest-trough pitch P1 of the windward-side corrugated fin 6U. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a parallel flow type heat exchanger.

  A parallel flow type heat exchanger in which a plurality of flat tubes are arranged between two header pipes so that a refrigerant passage inside the flat tubes communicates with the inside of the header pipe and corrugated fins are arranged between the flat tubes is a car. Widely used for air conditioners. Examples thereof can be seen in Patent Documents 1 and 2.

  The heat exchanger described in Patent Document 1 has a header pipe arranged horizontally and a flat tube arranged vertically, and the corrugated fin has a valley shape with the center in the depth direction of the heat exchanger as the bottom. . A through-hole is provided at a location where the corrugated fin is joined to the flat tube at the bottom of the corrugated fin. When defrosting operation is performed to melt the frost adhering to the heat exchanger, the melted water is drained from the through-hole.

In the heat exchanger described in Patent Document 2, at least one of the front and rear end surfaces of the flat tube protrudes from the corrugated fin end portion in the vertical direction. Alternatively, the corrugated fin end protrudes from at least one of the front and rear end faces of the flat tube.
JP 2005-24187 A JP 2004-177082 A

  When a parallel flow type heat exchanger is used as an evaporator, frost adheres to the flat tubes and corrugated fins depending on the ambient air temperature conditions and operating conditions. An object of this invention is to lengthen the time which becomes a clogged state with frost by equalizing the condition of frost.

  In order to achieve the above-mentioned object, the present invention provides two horizontal header pipes arranged in parallel at intervals, and a plurality of vertical header pipes arranged at a predetermined pitch between the two header pipes. A heat exchanger comprising a vertical flat tube having a refrigerant passage communicating with the inside of the header pipe and a corrugated fin disposed between the flat tubes, wherein the corrugated fin is connected to the windward corrugated fin and the leeward corrugated fin The heat exchange capacity of the leeward corrugated fin is made larger than the heat exchange capacity of the windward corrugated fin.

  The higher the heat exchange capacity, the easier it is to frost moisture in the air. In the above configuration, since the region where frost formation is likely to occur is shifted to the leeward side, when viewed from the air passing through the corrugated fins, it passes through the windward corrugated fins with a relatively small heat exchange capacity while the moisture content is large. After the moisture content is reduced, the leeward corrugated fin having a relatively large heat exchanging capacity is passed through, and the frost formation on the leeward corrugated fin and the frost formation on the leeward corrugated fin are balanced. As a result, a situation in which frost is concentrated on the windward side is avoided, and the time when the frost is clogged is extended, so that the interval of the defrosting operation can be increased and the operation efficiency is improved.

  In the heat exchanger configured as described above, it is preferable that the difference in the heat exchange capacity is generated by setting the peak-valley pitch of the leeward corrugated fin smaller than the peak-valley pitch of the windward corrugated fin.

  According to such a configuration, the heat exchange capability of the leeward corrugated fin can be made larger than the heat exchange capability of the leeward corrugated fin without increasing the size of the corrugated fin.

  In the heat exchanger having the above-described configuration, the length of the leeward corrugated fin in the same direction is larger than the length of the leeward corrugated fin in the air flow direction, thereby causing a difference in the heat exchange capacity. It is preferable.

  According to such a configuration, the heat exchange capability of the leeward corrugated fin can be made larger than the heat exchange capability of the upwind corrugated fin without significantly affecting the ventilation resistance of the corrugated fin.

  In the heat exchanger configured as described above, it is preferable that the fin surface of the leeward corrugated fin has a downward slope toward the leeward side, and the fin surface of the leeward corrugated fin has an upward slope toward the leeward side. .

  According to such a structure, the heat exchange efficiency as the whole heat exchanger improves rather than the case where a corrugated fin is arrange | positioned horizontally.

  In the heat exchanger configured as described above, it is preferable that the slope of the leeward corrugated fin is steeper than the slope of the leeward corrugated fin.

  According to such a configuration, the air resistance of the leeward corrugated fin is increased, and the heat exchange efficiency of the leeward corrugated fin is improved.

  In the heat exchanger configured as described above, it is preferable that the windward end portion of the windward corrugated fin protrudes from the windward end portion of the flat tube.

  According to such a configuration, since the flowing air contacts the windward corrugated fin before contacting the flat tube, frost formation on the flat tube can be reduced.

  According to the present invention, the degree of frosting can be made uniform on the windward side and the leeward side of the flat tubes and corrugated fins, and the time when the frost is clogged can be extended. And thereby, the interval of a defrost operation can be taken long and operating efficiency can be improved.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 is a schematic vertical sectional view showing a schematic structure of a heat exchanger, FIG. 2 is a sectional view taken along the line AA in FIG. 1, FIG. 3 is an enlarged partial horizontal sectional view, and FIG. FIG. 5 is a cross-sectional view taken along the line CC in FIG. 3, FIG. 6 is a perspective view of a flat tube and corrugated fins, and FIG. 7 is a complete set. It is a side view of a flat tube and a corrugated fin.

  In the heat exchanger 1, two horizontal header pipes 2 and 3 are arranged in parallel with an interval in the vertical direction, and a plurality of vertical flat tubes 4 are arranged between the header pipes 2 and 3 at a predetermined pitch. The flat tube 4 is an elongated molded product obtained by extruding a metal having good heat conductivity such as aluminum, and a refrigerant passage 5 through which a refrigerant flows is formed inside. Since the flat tube 4 is disposed so that the extrusion molding direction is vertical, the refrigerant flow direction of the refrigerant passage 5 is also vertical. Each refrigerant passage 5 communicates with the inside of the header pipes 2 and 3. In FIG. 1, the upper side of the drawing is the upper side in the vertical direction, the lower side of the drawing is the lower side in the vertical direction, and a plurality of flat tubes 4 are arranged between the upper header pipe 2 and the lower header pipe 3 in the longitudinal direction. The configuration is arranged at a predetermined pitch.

  The header pipes 2 and 3 and the flat tube 4 are fixed by welding. As shown in FIGS. 3 and 6, a plurality of refrigerant passages 5 having the same cross-sectional shape and the same cross-sectional area are arranged, so that the flat tube 4 has a harmonica-like cross section. Corrugated fins 6 are disposed between the flat tubes 4. The flat tube 4 and the corrugated fin 6 are fixed by welding. In addition to the flat tube 4, the header pipes 2 and 3 and the corrugated fin 6 are also made of a metal (for example, aluminum) having good heat conduction.

  Since many flat tubes 4 are provided between the header pipes 2 and 3 and corrugated fins 6 are provided between the flat tubes 4, the heat exchanger 1 has a large heat radiation (heat absorption) area, and efficiently exchanges heat. It can be performed. A refrigerant inlet 7 is provided at one end of the lower header pipe 3, and a refrigerant outlet 8 is provided at one end of the upper header pipe 2 at a position diagonal to the refrigerant inlet 7.

  Subsequently, the structure of the corrugated fin 6 will be described with reference to FIGS. 2, 3, 6, and 7. 2, 3, and 7, the left side of the drawing is the leeward side, and the right side of the drawing is the leeward side. In FIG.

  As shown in FIGS. 2 and 3, the corrugated fin 6 is divided into an upwind corrugated fin 6 </ b> U and a downwind corrugated fin 6 </ b> D, and each is welded to the flat tube 4. The windward corrugated fin 6U has a downward slope toward the leeward side of the fin surface. The leeward side corrugated fin 6 </ b> D has a fin surface with an upward slope toward the leeward side. The descending slope of the leeward corrugated fin 6U and the ascending slope of the leeward corrugated fin 6D have the same angle. The lengths of the windward corrugated fins 6U and the leeward corrugated fins 6D in the air flow direction are equal to each other.

  As shown in FIGS. 2, 4, and 5, the peak-valley pitch of the leeward corrugated fin 6 </ b> D is smaller than the peak-valley pitch of the leeward corrugated fin 6 </ b> U. That is, the peak-valley pitch P2 of the leeward corrugated fin 6D is ½ of the peak-valley pitch P1 of the leeward corrugated fin 6U. Note that the peak-valley pitch P2 of the leeward corrugated fin 6D is ½ of the peak-valley pitch P1 of the leeward corrugated fin 6U is one design example and does not define the content of the invention.

  The leeward corrugated fin 6U and the leeward corrugated fin 6D are not in close contact with each other, but are arranged so that a gap 9 is formed between the leeward end of the leeward corrugated fin 6U and the leeward end of the leeward corrugated fin 6D. ing. A configuration may be adopted in which a gap 9 is generated in a portion other than the contact portion by causing the leeward side end portion of the windward side corrugated fin 6U and the windward side end portion of the leeward side corrugated fin 6D to face each other and partially contact each other. . The gap 9 is set to such a size that the water droplets attached to the leeward end of the leeward corrugated fin 6U and the water droplets attached to the leeward end of the leeward corrugated fin 6D can be combined.

  When the refrigerant flows through the heat exchanger 1 while blowing air with a fan (not shown), in the operation mode in which the heat exchanger 1 is used as an evaporator (for example, outdoor of a separate air conditioner composed of an indoor unit and an outdoor unit) When the heat exchanger 1 is used to perform a heating operation, the heat exchanger 1 acts as an evaporator.) The heat exchanger 1 takes heat from the air and conversely releases cold energy into the air. Since the fin surfaces of the windward corrugated fin 6U and the leeward corrugated fin 6D are respectively inclined, the corrugated fin 6 as a whole is longer in the air flow direction than the case where the corrugated fin is horizontal without being inclined. It exists in the extended form, and high heat exchange performance can be obtained.

  When comparing the windward side corrugated fin 6U and the leeward side corrugated fin 6D, the leeward side corrugated fin 6D has a smaller peak-to-valley pitch P2, and therefore has a larger surface area than the windward side corrugated fin 6U, and thus has a larger heat exchange capability.

  When the operation of taking the heat from the air is continued, moisture in the air is condensed on the surface of the windward corrugated fin 6U, the surface of the leeward corrugated fin 6D, and the surface of the flat tube 4. When water droplets that were initially finely gathered into large water droplets, they flow down along the slope surface of the windward corrugated fin 6U or the leeward corrugated fin 6D and reach the gap 9. If the gap 9 is wide, the water droplets will only cause a bridging phenomenon at the leeward end of the leeward corrugated fin 6U or the leeward end of the leeward corrugated fin 6D. However, the gap 9 is set to such a size that the water droplets attached to the leeward end of the leeward corrugated fin 6U and the water droplets attached to the leeward end of the leeward corrugated fin 6D can be combined. When the water droplets on the fins 6U and the water droplets on the leeward side corrugated fin 6D meet at the gap 9, they break up and merge with each other, and flow out of the gap 9 without causing a bridging phenomenon.

  In the operation mode in which the heat exchanger 1 is used as an evaporator (the operation mode in which the heat exchanger 1 takes heat from the outdoor air), the surface of the flat tube 4 and the corrugated fin 6 depending on the ambient air temperature condition and the operation condition. In some cases, moisture in the air adheres as frost. As time goes on, frost increases in thickness and reduces heat exchange performance, so it must sometimes be defrosted to melt the frost. When defrosted water in which frost has melted also meets in the gap 9, the surface tensions of the defrosted water break apart and coalesce and flow out of the gap 9 without causing a bridging phenomenon. For this reason, when returning from the defrosting operation to the normal operation, water droplets remaining without being drained are not frozen and the heat exchange performance is not impaired.

  When the moisture in the air becomes frost and adheres to the corrugated fins 6, the air passing through the corrugated fins 6 passes through the windward corrugated fins 6 U having a relatively small heat exchange capacity while the moisture content is large, Since the leeward corrugated fin 6D having a relatively large heat exchange capacity passes through the leeward corrugated fin 6D after the amount is reduced, the frost formation on the upwind corrugated fin 6U and the frost formation on the leeward corrugated fin 6D are balanced. As a result, a situation in which frost is concentrated on the windward side is avoided, and the time when the frost is clogged is extended, so that the interval of the defrosting operation can be increased and the operation efficiency is improved.

  Further, by making the peak-valley pitch P2 of the leeward corrugated fin 6D smaller than the peak-valley pitch P1 of the leeward corrugated fin 6U, the heat of the leeward corrugated fin 6D can be increased without increasing the size of the corrugated fin 6. The exchange capacity can be made larger than the heat exchange capacity of the windward corrugated fin 6U.

  The descending slope of the windward corrugated fin 6U and the ascending slope of the leeward corrugated fin 6D can be selected in the range of 5 ° to 40 °. If the gradient becomes steep, the heat exchange area increases and drainage becomes easier, while resistance to air flow is good. In addition, the distance between the flat tubes 4 is 5.5 mm, the thickness of the flat tubes 4 is 1.3 mm, the horizontal length of the windward corrugated fin 6U and the leeward corrugated fin 6D in the air flow direction is 18 mm, respectively, and the windward side. Examples are numerical values such that the peak-to-valley pitches of the corrugated fins 6U and the leeward corrugated fins 6D are 2 mm to 3 mm, and the size of the gap 9 is 0.5 mm at the maximum. Needless to say, these numerical values are merely examples, and do not define the contents of the invention.

  Next, other embodiments of the present invention will be described.

  A second embodiment of the present invention is shown in FIG. FIG. 8 is a cross-sectional view similar to FIG. In FIG. 8, the left side of the drawing is the windward side, and the right side of the drawing is the leeward side.

The second embodiment differs from the first embodiment in the length of the windward corrugated fin 6U.
That is, the length of the windward corrugated fin 6U in the air flow direction is longer than that of the first embodiment, and the windward end of the windward corrugated fin 6U protrudes from the windward end of the flat tube 4.

  If comprised as mentioned above, since the flowing air contacts the windward corrugated fin 6U and contacts there with frost before contacting the flat tube 4, frost formation to the flat tube 4 can be decreased.

  Although the windward corrugated fin 6U becomes longer and the area is slightly increased, the heat exchange capability of the windward corrugated fin 6U does not exceed the heat exchange capability of the leeward corrugated fin 6D. Therefore, the balance between frost formation on the windward side corrugated fin 6U and frost formation on the leeward side corrugated fin 6D is maintained in substantially the same manner as in the first embodiment.

  A third embodiment of the present invention is shown in FIG. FIG. 9 is a cross-sectional view similar to FIG. In FIG. 9, the left side of the paper is the windward side, and the right side of the paper is the leeward side.

  The third embodiment differs from the first embodiment in the ratio of the length of the windward corrugated fin 6U and the leeward corrugated fin 6D in the air flow direction. That is, in the third embodiment, when the lengths in the air flow direction are compared, the leeward corrugated fin 6D is larger than the windward corrugated fin 6U.

  When the ratio of the lengths of the windward corrugated fins 6U and the leeward corrugated fins 6D in the air flow direction is changed as described above, the heat of the leeward corrugated fins 6D is not greatly affected by the ventilation resistance of the corrugated fins 6. The exchange capacity can be made larger than the heat exchange capacity of the windward corrugated fin 6U. In this configuration, when the heat exchange capacity of the leeward corrugated fin 6D is already greater than the heat exchange capacity of the leeward corrugated fin 6U due to the difference between the peak and valley pitches, the difference in the heat exchange capacity is reduced. Helps to expand.

  A fourth embodiment of the present invention is shown in FIGS. FIG. 10 is a perspective view of a set of flat tubes and corrugated fins, and FIG. 11 is a side view of the set of flat tubes and corrugated fins. In FIG. 10, the left front side of the drawing is the windward side, the right back side of the drawing is the leeward side, and the left side of the drawing is the upwind side and the right side of the drawing is the leeward side in FIG.

  The fourth embodiment differs from the first embodiment in that the peak-valley pitch of the windward corrugated fin 6U and the peak-valley pitch of the leeward corrugated fin 6D are the same, and the downhill slope of the windward corrugated fin 6U. Rather than that, the upward slope of the leeward corrugated fin 6D is steeper. By comprising in this way, the air resistance of the leeward corrugated fin 6D becomes large, and the heat exchange efficiency of the leeward corrugated fin 6D improves.

  In each of the above embodiments, the windward corrugated fin 6U and the leeward corrugated fin 6D are configured to have gradients. However, when the windward corrugated fin 6U and the leeward corrugated fin 6D have no gradient, that is, horizontal. The present invention is also applicable.

  As mentioned above, although each embodiment of the present invention was described, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

    The present invention is widely applicable to parallel flow heat exchangers.

Model vertical cross section showing the schematic structure of the heat exchanger Sectional drawing cut | disconnected along the AA line of FIG. Expanded horizontal sectional view of heat exchanger Sectional drawing cut | disconnected along the BB line of FIG. Sectional drawing cut | disconnected along CC line of FIG. Perspective view of a set of flat tubes and corrugated fins Side view of a set of flat tubes and corrugated fins Sectional view similar to FIG. 2 according to the second embodiment Sectional view similar to FIG. 2 according to the third embodiment A perspective view similar to FIG. 6 according to the fourth embodiment Side view similar to FIG. 7 according to the fourth embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2, 3 Header pipe 4 Flat tube 5 Refrigerant passage 6 Corrugated fin 6U Upwind side corrugated fin 6D Downward side corrugated fin

Claims (6)

Two horizontal header pipes arranged parallel to each other at a distance from each other, and a plurality of vertical header pipes arranged at a predetermined pitch between the two header pipes, communicated with the interior of the header pipe through a vertical refrigerant passage provided therein. In a heat exchanger comprising a vertical flat tube and corrugated fins disposed between the flat tubes,
The heat exchanger according to claim 1, wherein the corrugated fin is divided into a leeward corrugated fin and a leeward corrugated fin, and the heat exchange capacity of the leeward corrugated fin is made larger than the heat exchange capacity of the windward corrugated fin. 2. The heat exchange according to claim 1, wherein a difference in the heat exchange capacity is generated by setting a peak-valley pitch of the leeward corrugated fin smaller than a peak-valley pitch of the windward corrugated fin. vessel. The heat exchange capacity difference is generated by making the length of the leeward corrugated fin in the same direction larger than the length of the leeward corrugated fin in the air flow direction. The heat exchanger as described in. The fin surface of the leeward corrugated fin has a downward slope toward the leeward side, and the fin surface of the leeward corrugated fin has an upward slope toward the leeward side. The heat exchanger according to any one of the above. The heat exchanger according to claim 4, wherein the slope of the leeward corrugated fin is steeper than the slope of the leeward corrugated fin. The heat exchanger according to any one of claims 1 to 5, wherein an upwind end portion of the upwind corrugated fin protrudes from an upwind end portion of the flat tube.

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