JP2014224638A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat exchange performance and improve mass productivity while ensuring condensed water drainage performance and inhibiting sudden degradation in performance due to frosting.SOLUTION: A heat exchanger is configured so that many crests 201 and troughs 202 are alternately provided on a corrugated fin 2 in an air flow direction, and that a drainage path 206 formed of a stepped portion equal to or greater than a thickness of the corrugated fin 2 is provided in the troughs 202. This configuration enables the air to repeat separation and reattachment of a temperature boundary layer along the many crests 201 and troughs 202 to improve heat transfer performance, and inhibits degradation in performance caused by closure of an air flow path due to adhesion and growth of frosts, and enables condensed water in a case of using the heat exchanger as an evaporator to smoothly flow down from the drainage path 206 provided in the troughs 202. Furthermore, the drainage path 206 is excellent in mass productivity since no scraps are generated by punching.

Description

  The present invention relates to a heat exchanger used for an outdoor unit or the like of an air conditioner that also serves as an air conditioner, and relates to a heat exchanger having corrugated fins between vertical flat tubes and adjacent flat tubes.

  Conventionally, as this type of heat exchanger, those shown in FIGS. 3 and 4 are generally known. 3 and 4, the heat exchanger has a horizontal direction in which a longitudinal direction is a vertical direction and a plurality of flat tubes 1 arranged in parallel with each other at a predetermined pitch and the upper ends of the flat tubes 1 are connected in communication. The upper header 10, the horizontal lower header 11 that connects the lower ends of the flat tubes 1, and the adjacent flat tubes 1 are arranged or joined to the flat tubes 1 by brazing or bonding. The corrugated fins 2 are configured such that air passes through the gaps between the corrugated fins 2 to exchange heat.

  In such a heat exchanger, as shown in FIGS. 5 and 6, the corrugated fin 2 is formed such that the top 21 and the intermediate wall 22 are alternately bent and formed, and the top 21 of the corrugated fin 2 is formed flat. By defining the fin angle θ1, the length L1 of the flat top portion 21, the louver length L2, the louver angle θ2, and the louver pitch L3 within predetermined numerical ranges, respectively, the heat transfer coefficient is not significantly reduced. Some have improved water drainage when used as an evaporator (see, for example, Patent Document 1).

  However, such a heat exchanger has the following problems. That is, this heat exchanger is used in an outdoor unit of an air conditioner that also serves as an air conditioner. When the air conditioner is heated and operated, the outside air temperature becomes low, and the surface temperature of the corrugated fins 2 becomes below freezing point, The moisture of the water adheres to the corrugated fins 2 as frost, and the frosting gradually progresses, the frost becomes thick, and eventually the air ventilation path is blocked by the frosting. During this time, the ventilation resistance of the heat exchanger increases, the air volume decreases, the evaporation performance decreases, and the heating performance of the air conditioner decreases. In particular, the corrugated fin 2 is provided with a louver 2a for high performance, but the front edge of the louver 2a has a high local heat transfer rate, so that frosting proceeds quickly and the louver 2a is provided. Therefore, the substantial intervals between the corrugated fins 2 are narrow, the ventilation path is blocked by frosting very quickly, and the heating capacity is extremely reduced.

  Therefore, the ventilated upstream end of the corrugated fin 2 has no louver, protrudes to the windward side from the end of the flat tube, and every other flat tube is replaced with a partition plate, or the shape of the louver A heat exchanger that sequentially changes from the windward to the leeward has been proposed (see, for example, Patent Document 2).

  Further, a heat exchanger in which a louver having a small angle is formed in the windward portion of the corrugated fin 2 and a louver having a larger angle than the windward portion is formed in the leeward portion or the louver in the windward portion of the corrugated fin 2 is eliminated. Has been proposed (see, for example, Patent Document 3).

  Further, the corrugated fin 2 is provided with a louver portion having a large angle and a flat portion or uneven portion or a louver portion having a small angle, and the position of the louver portion having a large angle and the flat portion or the concavo-convex portion or the louver portion having a small angle is determined by the gas flow. There has been proposed a heat exchanger in which corrugated fins adjacent to each other with a path interposed are alternately arranged (see, for example, Patent Document 4).

Further, a heat exchanger has been proposed in which corrugated fins are alternately provided with a large number of peaks and valleys whose ridgelines extend in a direction perpendicular to the air flow direction, and at least cuts are provided in the ridgelines of the valleys (for example, (See Patent Document 5).

  7-9 shows the principal part of the corrugated fin of the conventional heat exchanger shown by patent document 5. FIG. 7, in the corrugated fin 2 surface, as shown in a partially cutaway perspective view of the corrugated fin 2 in the air passage direction (FIG. 8), a notch 203 is formed in a ridge line extending in a direction perpendicular to the air flow direction. A plurality of troughs 201 and troughs 202 having cuts 204 in ridges extending in a direction perpendicular to the air flow direction are alternately provided in the air flow direction. With such a configuration, the air flowing into the heat exchanger flows along the undulations of a large number of peaks 201 and valleys 202 that are alternately provided in the air flow direction, and the temperature boundary layer is separated and reattached. The heat transfer performance is improved because of repetition, and when the heat exchanger is used as an evaporator, the condensed water generated on the fin surface by heat exchange with the circulating air passes through the cuts 204 provided in the ridgeline of the valley portion 202. As the corrugated fins 2 flow down, water drainability is also ensured.

JP-A-6-241678 JP-A-6-147785 JP-A-6-221787 Japanese Patent No. 3068761 JP 2004-270959 A

  However, in the conventional configuration described above, particularly the conventional configuration shown in Patent Document 1 to Patent Document 4, a louver for improving performance is provided somewhere in the corrugated fin 2 in any case. However, the louver may reduce the substantial interval between the corrugated fin stages, so that the blockage of the ventilation path due to frosting cannot be significantly delayed, and the heating performance of the air conditioner at a low outside temperature is drastically reduced. There is a problem that only a certain degree of suppression of such a decrease can be achieved.

  Further, in the configuration shown in Patent Document 5, as shown in FIG. 9, there is a risk of scrap 210 being generated by punching when the fin is manufactured, and there is a risk of biting into the mold. However, it has a problem that it is necessary and lacks mass productivity.

  The present invention solves such a conventional problem, and greatly improves both the condensation performance and the evaporation performance, and further allows the condensed water generated on the fin surface to flow down well when used as an evaporator, And it aims at providing the heat exchanger excellent in mass-productivity, suppressing the rapid performance fall by frost when used as a heat exchanger of the outdoor unit of the air conditioner combined with air conditioning.

  In order to solve the above problems, the heat exchanger of the present invention is provided with a plurality of ridges and valleys alternately extending in a direction perpendicular to the air flow direction in the corrugated fin, and at least the ridge line of the valley is the corrugated fin. The drainage path which consists of a level | step difference more than this board thickness is provided.

As a result, the air flowing into the heat exchanger flows along the undulations of a number of peaks and valleys in which ridge lines alternately provided in the air flow direction extend in a direction perpendicular to the air flow direction. Since the heat transfer performance is improved by repeating the peeling and reattachment, the effect of greatly increasing the heat exchange capability can be obtained even when the heat exchanger of the present invention is used as either a condenser or an evaporator.
Further, when used as an evaporator, the condensed water generated on the fin surface by heat exchange with the circulating air passes through a drainage path composed of at least a plate thickness of the corrugated fin provided on the ridge line of the valley portion while corrugating. As the fins flow down, excellent water drainage is obtained. In addition, the heat exchanger of the present invention is used for an outdoor unit of an air conditioner that also serves as an air conditioner, and during the heating operation of the air conditioner, it frosts on the fin surface when the outside air temperature decreases, but the heat transfer performance is improved. For this reason, the undulating shape of the corrugated fin provided by alternating repeated peaks and troughs does not significantly close the distance between adjacent corrugated fins as louvers or cuts and raises. The flow path is not blocked, and the effect of suppressing the rapid and significant performance deterioration can be obtained. Furthermore, since the drainage path formed of a step larger than the corrugated fin plate thickness provided at least on the ridge line of the valley portion has a shape that does not generate scrap due to punching, it avoids the risk of scraping into the mold. It is also possible to obtain the effect that no response is required and the mass productivity is excellent.

  According to the present invention, both the condensation performance and the evaporation performance can be greatly improved, and when used as an evaporator, the condensed water generated on the fin surface by the heat exchange with the circulating air can flow well. And when it is used as a heat exchanger for an outdoor unit of an air conditioner that also serves as an air conditioner and frosts on the fin surface during the heating operation of the air conditioner, such as when the outside air temperature decreases, It is possible to provide a heat exchanger excellent in mass productivity while maintaining the effect of suppressing the performance from being remarkably deteriorated due to a sudden blockage of the air flow path.

The expanded perspective view which shows the principal part of the heat exchanger in Embodiment 1 of this invention (A) (b) The expanded sectional view of the air passage direction of the corrugated fin of the heat exchanger in Embodiment 1 Perspective view showing a conventional heat exchanger The expansion perspective view of the principal part of the conventional heat exchanger shown in FIG. An enlarged front view showing an example of a corrugated fin of a conventional heat exchanger The expanded sectional view of the air passage direction of the corrugated fin of the conventional heat exchanger shown in FIG. The principal part expansion perspective view which shows the other example of the corrugated fin of the conventional heat exchanger The partial cutaway perspective view of the corrugated fin of the conventional heat exchanger shown in FIG. The expanded sectional view of the air passage direction of the corrugated fin of the conventional heat exchanger shown in FIG.

  According to a first aspect of the present invention, a corrugated fin is provided with a large number of ridges and valleys alternately extending in a direction perpendicular to the air flow direction, and at least a ridge line of the trough has a step greater than the plate thickness of the corrugated fin. A route is provided.

As a result, the air flowing into the heat exchanger flows along the undulations of a number of peaks and valleys in which ridge lines alternately provided in the air flow direction extend in a direction perpendicular to the air flow direction. Since heat transfer performance is improved by repeating the peeling and reattachment, the effect of greatly increasing the heat exchange capacity can be obtained when the heat exchanger of the present invention is used as either a condenser or an evaporator. is there. Further, when used as an evaporator, the condensed water generated on the fin surface by heat exchange with the circulating air passes through a drainage path composed of at least a plate thickness of the corrugated fin provided on the ridge line of the valley portion while corrugating. As the fins flow down, excellent water drainage is obtained. In addition, the heat exchanger of the present invention is used for an outdoor unit of an air conditioner that also serves as an air conditioner, and during the heating operation of the air conditioner, it frosts on the fin surface when the outside air temperature decreases, but the heat transfer performance is improved. Therefore, the undulating shape by alternating repetition of peaks and troughs provided in the corrugated fins does not bring the distance between adjacent corrugated fins significantly like louvers or cuts and raises,
The air flow path is not abruptly closed due to frost adhesion and growth, and the effect of suppressing a significant drop in performance is obtained. Furthermore, since the drainage path formed of a step larger than the corrugated fin plate thickness provided at least on the ridge line of the valley portion has a shape that does not generate scrap due to punching, it avoids the risk of scraping into the mold. No response is required and the effect of excellent mass productivity is obtained.

  According to a second aspect of the present invention, in the first aspect of the present invention, a drainage path composed of steps equal to or greater than the plate thickness of the corrugated fin is provided on both the ridge line of the corrugated fin and the ridge line of the trough.

  Thereby, when assembling the heat exchanger, the corrugated fins can be either up or down, and the workability can be improved.

  According to a third invention, in the first or second invention, the drainage path composed of a step larger than the thickness of the corrugated fin is opened to the leeward side with respect to the airflow direction.

  As a result, the front edge portion having a high local heat transfer coefficient can be eliminated, and the effect of preventing the air flow path from being suddenly blocked due to the progress of frost formation and the performance from being significantly reduced can be further enhanced. The increase in resistance can be minimized, which is effective.

  Embodiments of the present invention will be described below with reference to the drawings. The basic structure of the heat exchanger of the present invention is parallel to each other at a predetermined pitch with the longitudinal direction set to the vertical direction in the same manner as the general heat exchanger shown in FIGS. 3 and 4 described in the prior art. A number of flat tubes 1 arranged, a horizontal upper header 10 that connects the upper ends of the flat tubes 1, a horizontal lower header 11 that connects the lower ends of the flat tubes 1, The corrugated fin 1 is disposed between the flat tubes 1, joined or closely bonded to the flat tubes 1 by brazing or bonding, repeatedly bent and formed so that air passes through the gaps. Since the surface shape is characteristic, the surface shape of the corrugated fin will be described in detail.

(Embodiment 1)
The first embodiment will be described with reference to FIGS.

  FIG. 1 is an enlarged perspective view showing a main part of the heat exchanger according to Embodiment 1 of the present invention.

  In FIG. 1, on the surface of the corrugated fin 2 of the flat tube 1 in the vertical direction, as shown in FIG. 2, which is an enlarged sectional view of the corrugated fin 2 in the air passage direction, a ridge line extending in a direction perpendicular to the air flow direction is formed. A plurality of ridges 201 and valleys 202 are alternately provided, and drainage channels 205 and 206 are formed by cutting the ridgelines of the ridges 201 and valleys 202 to form steps that are greater than the thickness of the corrugated fins. It is formed.

  In the above configuration, the air that has flowed into the heat exchanger flows along the undulations of a number of peaks 201 and valleys 202 in which ridge lines alternately provided in the air flow direction extend in a direction perpendicular to the air flow direction, Repeated peeling and reattachment of the temperature boundary layer improves heat transfer performance, and even when the heat exchanger of this embodiment is used as either a condenser or an evaporator, the effect of greatly increasing the heat exchange capability is obtained. .

  Further, when the heat exchanger of the present embodiment is used as an evaporator, the condensed water generated on the fin surface by heat exchange with the circulating air is composed of a step larger than the thickness of the corrugated fin provided on the ridge line of the trough 202. Since the corrugated fins 2 flow down through the drainage path 206, excellent water drainage is obtained.

  Furthermore, when the heat exchanger of this embodiment is used for an outdoor unit of an air conditioner that also serves as an air conditioner and the outside air temperature decreases during the heating operation of the air conditioner, frosting proceeds on the surface of the corrugated fin 2. However, the undulating shape of the corrugated fins 2 by alternately repeating a number of ridges 201 and troughs 202 provided in the corrugated fins 2 to improve heat transfer performance greatly increases the spacing between adjacent corrugated fins, as in the case of conventional heat exchanger louvers. In addition, frost formation does not proceed in a concentrated manner at the front edge of the louver with a high local heat transfer coefficient, so the air flow path is suddenly blocked by frost adhesion and growth. In this way, an effect of suppressing the performance from rapidly deteriorating rapidly can be obtained.

  Furthermore, the drainage path 206 made of a step larger than the plate thickness of the corrugated fin provided on the ridgeline of the valley portion 202 shears the fin along the ridgeline of the valley portion 202, but at the end of the ridgeline of the valley portion 202. Since the fins are kept in a connected state, no scrap is generated, and it is not necessary to take measures to avoid the risk of the scrap biting into the mold, so that an effect of excellent mass productivity can be obtained.

  Furthermore, as shown in FIG. 2A, a step larger than the plate thickness of the corrugated fin provided on the ridge line of the valley portion 202 is opened toward the leeward side so that the end of the step does not face the leeward side. By configuring the drainage path 206, the front edge portion having a high local heat transfer coefficient is eliminated, and the effect of suppressing the rapid deterioration of the performance due to the sudden closing of the air flow path due to the progress of frosting is further enhanced. And increase in ventilation resistance can be minimized.

  On the other hand, as shown in FIG. 2B, local heat transfer is performed by configuring the drainage path 206 so that a step equal to or greater than the plate thickness of the corrugated fin provided on the ridgeline of the valley portion 202 is opened toward the windward side. The leading edge having a high rate can be used effectively, and the heat transfer performance can be improved.

  Alternatively, by combining the configurations shown in FIGS. 2A and 2B, for example, on the windward side having a relatively high heat transfer coefficient, the corrugation provided on the ridgeline of the valley portion 202 shown in FIG. A corrugated fin plate provided on the ridge line of the valley portion 202 shown in FIG. 2 (b) on the leeward side having a relatively low heat transfer coefficient, having a structure in which a step equal to or greater than the fin thickness is opened toward the leeward side. By adopting a configuration in which a step having a thickness or more is opened toward the windward side, the heat transfer performance of the entire heat exchanger can be made appropriate and the heat transfer performance can be further improved.

  Further, in the present embodiment, a drainage path 205 having a level difference equal to or greater than the corrugated fin thickness is provided on the ridge line of the peak part 201, and both the drainage path 205 of the peak part 201 and the drainage path 206 of the valley part 202 are provided. Therefore, when assembling the heat exchanger, the corrugated fin 2 can be either up or down, and workability is improved.

  In this embodiment, drainage paths 205 and 206 are provided in both the mountain 201 and valley 202 to improve the heat exchanger assembly. However, in order to ensure drainage, the valley 202 is secured. It is sufficient that the drainage path 206 is provided only on the ridge line, and whether or not the drainage path 206 is provided in the mountain portion 201 may be appropriately selected as necessary.

  The present invention can greatly improve both the condensing performance and the evaporating performance, and further allows the condensed water generated on the fin surface to flow down when used as an evaporator, and is used for an air conditioner that also serves as an air conditioner. It is possible to provide a heat exchanger with excellent mass productivity while suppressing a sudden drop in performance due to frost formation when used as an outdoor unit heat exchanger. Widely applied to air conditioners for business use as well as home use can do.

DESCRIPTION OF SYMBOLS 1 Flat tube 2 Corrugated fin 10 Upper header 11 Lower header 201 Mountain part 202 Valley part 205,206 Drainage path

Claims (3)

A number of flat tubes arranged in parallel with each other at a predetermined pitch with the longitudinal direction set as a vertical direction, a horizontal upper header that connects the upper ends of the flat tubes, and a horizontal that connects the lower ends of the flat tubes In a heat exchanger having a corrugated fin that is disposed between a lower header in the direction and the adjacent flat tube, and a portion adjacent to the flat tube is joined or closely attached to the flat tube, and air passes through the gap. In the corrugated fin, a plurality of ridges and valleys whose ridge lines extend in a direction perpendicular to the air flow direction are alternately provided in the air flow direction. A heat exchanger with a drainage path. The heat exchanger according to claim 1, further comprising a drainage path including a step having a thickness equal to or greater than the thickness of the corrugated fin on both the ridgeline of the corrugated fin and the ridgeline of the trough. The heat exchanger according to claim 1 or 2, wherein a drainage path composed of a step having a thickness equal to or greater than the thickness of the corrugated fin is open to the leeward side with respect to the airflow direction.

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