JP2006046698A - Freezer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a freezer capable of shortening defrosting time by promoting falling of frost during defrosting operation in a cross fin and tube type heat exchanger. <P>SOLUTION: An air conditioner is composed by using the cross fin and tube type heat exchanger 2 having a plate fin 3 and a plurality of vertically arranged heat exchange pipes 5 as an outdoor side heat exchanger. An inlet side end of an air flow in the plate fin 3 of the outdoor side heat exchanger 2 is formed in a waveform shape comprised by vertically arranging a multiplicity of protruding parts 6 with substantially triangular cross sections. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is configured using a cross fin and tube type heat exchanger having fins and a plurality of stages of heat exchange pipes arranged in the vertical direction, and adheres when the heat exchanger is operated as an evaporator. The present invention relates to a refrigeration apparatus that performs a defrosting operation for removing frost.

  Generally, in a refrigeration system in which a heat exchanger is operated as an evaporator, the heat exchange surface of the heat exchanger is used when the temperature of the air that exchanges heat with the heat exchanger is low or when the evaporation temperature in the evaporator is low. Frost is generated. When frost occurs, the heat exchange capacity of the heat exchanger decreases, and as a result, the refrigeration capacity of the refrigeration apparatus also decreases.

  For example, in a heat pump type air conditioner that is a kind of refrigeration system, if the outside air temperature decreases during heating operation, the evaporation temperature in the outdoor heat exchanger operating as an evaporator decreases, and this outdoor heat exchanger Frost. When frosting occurs, the evaporation capacity of the outdoor heat exchanger decreases, and as a result, the heating capacity of the air conditioner decreases. Therefore, in the air conditioner, a defrosting operation for removing frost attached to the outdoor heat exchanger is appropriately performed.

  FIG. 8 is a schematic diagram showing a defrosting state in a conventional heat exchanger during a defrosting operation. The heat exchanger 41 is a cross fin and tube heat exchanger having plate fins 42 and a plurality of stages of heat exchange pipes 43 arranged in the vertical direction. As shown in FIG. 8A, when the frost 44 adheres to almost the entire plate fin 42, the defrosting operation is started. When the frost 44 starts to melt by the defrosting operation, the frost 44 starts to fall downward as shown in FIG. As shown in FIG. 8C, the frost 44 slides down the upstream portion and the downstream portion of the heat exchange pipe 43 in the plate fin 42. As the frost 44 slides down in this manner, the frost 44 is finally removed from the plate fins 42 as shown in FIG.

  However, since the amount of the frost 44 adhering to the upstream portion of the heat exchange pipe 43 is larger than that of the downstream portion, the frost 44 that slides down from the upper side, as shown in FIG. It accumulates on the side (upstream side in the air flow direction). Therefore, if the lower frost 44 is not removed, the upper frost 44 does not slide downward, and there is a problem that the defrosting time becomes long.

Patent Document 1 describes a heat exchanger that can shorten the defrosting time. In the heat exchanger described in Patent Document 1, a corrugated shape composed of a concave portion and a convex portion so that the end portions of the fins through which the heat exchange pipe passes are at an approximately equal distance from the heat exchange pipe. Is formed. In this heat exchanger, since the distance from the heat exchange pipe to the fin end is substantially the same, the heat conduction from the heat exchange pipe to the fin end during the defrosting operation is substantially equal. As a result, since the frost can be melted almost uniformly, the defrosting time can be shortened.
JP-A-8-61875

  In the heat exchanger described in Patent Document 1, the frost at the fin end can be almost uniformly melted. However, in order to prevent the frost from remaining and melt all the frost at the fin end. It is necessary to perform the defrosting operation for a long time to melt the frost. However, when the defrosting operation is performed for a long time, heating must be stopped during that time, and there is a problem that indoor comfort is impaired for a long time and energy required for the defrosting operation increases.

  An object of the present invention is to provide a refrigeration apparatus that can shorten the defrosting time by promoting the sliding of frost during the defrosting operation in the cross fin and tube type heat exchanger.

The invention according to claim 1 is configured using a cross fin and tube heat exchanger having fins and a plurality of stages of heat exchange pipes arranged in a vertical direction, and the heat exchanger is operated as an evaporator. In a refrigeration apparatus that performs a defrosting operation to remove frost sometimes attached,
In the refrigeration apparatus, the air flow inlet side end portion of the fin of the heat exchanger has a wave shape formed by arranging a number of protrusions having a substantially triangular cross section in the vertical direction.

  According to a second aspect of the present invention, the substantially triangular protrusion is formed corresponding to each heat exchange pipe, and the two inclined surfaces of each protrusion have a lower upper inclined surface length. It is characterized by being formed to be larger than the inclined surface on the side.

  According to a third aspect of the present invention, a plurality of the substantially triangular projections are formed with respect to the step pitch of the heat exchange pipe, and the length of two inclined surfaces in each projection is It is characterized by being formed to be substantially equal.

The invention described in claim 4 is characterized in that the fin is subjected to a surface treatment having water slidability and water repellency.
The invention according to claim 5 is characterized in that the fin is a waffle fin.

The invention according to claim 6 is characterized in that the heat exchanger has holes formed between the heat exchange pipes of the heat exchange pipe row in the fin.
The invention according to claim 7 is characterized in that the hole is formed on a center line passing through the center of each heat exchange pipe.

The invention according to claim 8 is characterized in that the hole is a rectangular hole extending in a vertical direction.
The invention according to claim 9 is configured using a cross fin and tube heat exchanger having fins and a plurality of stages of heat exchange pipes arranged in a vertical direction, and the heat exchanger is operated as an evaporator. In a refrigeration apparatus that performs a defrosting operation to remove frost sometimes attached,
In the refrigeration apparatus, the air flow inlet side end portion of the fin of the heat exchanger has a sliding acceleration mechanism that promotes sliding of frost during the defrosting operation.

  According to the first aspect of the present invention, the air flow inlet side end portion of the fin of the heat exchanger has a plurality of protrusions having a substantially triangular cross section protruding in the vertical direction and protruding toward the air flow upstream side. Therefore, when the heat exchanger operates as an evaporator, frost at the end on the inlet side adheres to a large number of protrusions. In the inlet side end where frost tends to adhere, the frost is separated and attached to a large number of protrusions. It becomes easy to melt. Moreover, since the upper inclined surface in each of the substantially triangular projections is inclined downward, the frost sliding down from above can be guided and slid down toward the upstream side of the airflow. Thus, the frost can be easily melted, and further, the frost can be guided and slid down by the inclined surface, so that the frost can be smoothly slid down and the defrosting time can be shortened.

  According to the second aspect of the present invention, the substantially triangular protrusion is formed corresponding to each heat exchange pipe, and the length of the upper inclined surface of the protrusion is larger than that of the lower inclined surface. Thus, the upper inclined surface can be made relatively long. In this shape, the effect | action which guides the frost which slides down along an inclined surface can be strengthened. Thereby, the frost sliding down from above can be smoothly guided and slid down along the upper inclined surface, so that the defrosting time can be shortened.

  According to the invention of claim 3, since the two isosceles triangle-shaped protrusions having substantially the same length of the two inclined surfaces are formed so as to be included with respect to the step pitch of the heat exchange pipe, Many protrusions that are relatively small and uniform in shape can be formed. In this shape, the effect | action which isolate | separates and adheres frost can be strengthened. As a result, frost can be easily melted and the defrosting time can be shortened.

  According to the fourth aspect of the present invention, since the fin is subjected to surface treatment having water slidability and water repellency, the frost melted by the defrosting operation can be smoothly slid downward, and the water droplets are also downward. Can flow down smoothly. As a result, the frost and water droplets can be prevented from remaining and fins can be defrosted more efficiently. Therefore, the defrosting time can be shortened.

  According to the fifth aspect of the present invention, the wave shape of the waffle fin promotes the frost and water droplets that have melted down and flow down. Defrosting can be performed more efficiently. Therefore, the defrosting time can be shortened.

  According to the sixth aspect of the present invention, since the holes are formed between the heat exchange pipes in the fin, the temperature around the hole in the fin is higher than that in other parts during the defrosting operation. Therefore, when the frost adhering to the fin is melted and slides downward by the defrosting operation, the frost is melted and divided around the hole. That is, the frost between the heat exchange pipes is divided by the holes and slides downward. Thereby, it is possible to suppress frost from remaining on the upper portion of the heat exchange pipe and to efficiently perform the defrosting of the fins, so that the defrosting time can be shortened.

  According to the seventh aspect of the invention, since the hole is formed on the center line passing through the center of each heat exchange pipe, the frost is divided just above the heat exchange pipe. Thereby, compared with the case where a hole is formed at a position shifted from the center line, it is possible to suppress the frost from remaining on the upper portion of the heat exchange pipe, and to efficiently defrost the fins. Therefore, the defrosting time can be shortened.

  According to the invention described in claim 8, since the rectangular holes extending in the vertical direction are formed between the heat exchange pipes, compared to the case where holes of other shapes such as circular holes are formed, between the heat exchange pipes. It becomes possible to promote the division of frost on the surface. Thereby, it is further suppressed that frost remains on the upper part of the heat exchange pipe, and the fin can be defrosted more efficiently. Therefore, the defrosting time can be shortened.

  According to the ninth aspect of the present invention, since the sliding-down promoting mechanism is provided at the inlet side end of the air flow in the fin of the heat exchanger, it adheres to the inlet side end when performing the defrosting operation. Frost can be slid smoothly. Therefore, the defrosting time can be shortened.

Hereinafter, embodiments of the refrigeration apparatus of the present invention will be described with reference to the drawings. In the following description, a heat pump type air conditioner that is a kind of refrigeration apparatus will be described.
(First embodiment)
FIG. 1 is a cross-sectional view of an outdoor heat exchanger 2 used in the air conditioner 1 according to the first embodiment of the present invention, and FIG. 2 is a refrigerant circuit diagram of the air conditioner 1.

  In the air conditioner 1, as shown in FIG. 2, the outdoor heat exchanger 2, the expansion valve 9, the indoor heat exchanger 10, the four-way switching valve 11, and the compressor 12 are connected by a refrigerant pipe, and a refrigerant circuit is formed. It is configured. During the cooling operation, the four-way switching valve 11 is set to the solid line side shown in FIG. In this state, the refrigerant discharged from the compressor 12 circulates in the order of the four-way switching valve 11, the outdoor heat exchanger 2, the expansion valve 9, the indoor heat exchanger 10, and the four-way switching valve 11. 12 is inhaled. By such circulation of the refrigerant, the outdoor heat exchanger 2 operates as a condenser, and the indoor heat exchanger 10 operates as an evaporator. In the outdoor heat exchanger 2 that operates as a condenser, the gas refrigerant exchanges heat with the outdoor air to become a liquid refrigerant, whereby the refrigerant radiates heat to the outdoor air. In the indoor heat exchanger 10 operating as an evaporator, the refrigerant exchanges heat with room air and evaporates to become a gas refrigerant, whereby the indoor air is absorbed by the refrigerant and cooled.

  On the other hand, at the time of heating operation, the four-way selector valve 11 is set to the broken line side shown in FIG. In this state, the refrigerant discharged from the compressor 12 is circulated in the order of the four-way switching valve 11, the indoor heat exchanger 10, the expansion valve 9, the outdoor heat exchanger 2, and the four-way switching valve 11. 12 is inhaled. By such circulation of the refrigerant, the indoor heat exchanger 10 operates as a condenser, and the outdoor heat exchanger 2 operates as an evaporator. In the indoor heat exchanger 10 that operates as a condenser, the gas refrigerant exchanges heat with the indoor air and condenses, whereby the indoor air is heated by heat radiation from the refrigerant. In the outdoor heat exchanger 2 that operates as an evaporator, the refrigerant exchanges heat with outdoor air and evaporates to become a gas refrigerant, whereby the refrigerant absorbs heat from the outdoor air.

  The defrosting operation is performed by a reverse method in which the refrigerant is circulated in a reverse cycle for a certain period of time during the heating operation. That is, the four-way switching valve 11 is set to the solid line side, and the refrigerant discharged from the compressor 12 is supplied to the four-way switching valve 11, the outdoor heat exchanger 2, the expansion valve 9, the indoor heat exchanger 10, and the four-way switching. Circulate in the order of the valves 11. Accordingly, the outdoor heat exchanger 2 operates as a condenser and dissipates heat from the refrigerant, so that frost is melted.

  As shown in FIG. 1, the outdoor heat exchanger 2 is a so-called cross fin and tube heat exchanger, in which a large number of plate fins 3 forming a heat exchange surface are spaced apart from each other in an air flow distribution direction 4. The plate fins 3 are arranged so as to pass through a heat exchange pipe 5 through which a refrigerant flows.

  In the outdoor heat exchanger 2, the plate fins 3 are arranged such that the longitudinal direction is parallel to the vertical direction. The heat exchange pipes 5 penetrating the plate fin 3 are arranged at equal intervals along the longitudinal direction from one end of the plate fin 3 to the other end. The plate fin includes all plate-like fins such as flat fins, slit fins, and waffle fins.

  In this embodiment, the inlet-side end portion of the air flow in the plate fin 3 of the outdoor heat exchanger 2 has a protrusion 6 having a substantially triangular cross section that protrudes toward the upstream side in the air flow direction 4. It is a wave shape formed by arranging a large number in the vertical direction. Specifically, the substantially triangular protrusion 6 is formed corresponding to each heat exchange pipe 5, and the length La of the upper inclined surface 6a in the protrusion 6 is the length of the lower inclined surface 6b. It is formed to be larger than the length Lb.

Various dimensions of the protrusion 6 and the positional relationship between the protrusion 6 and the heat exchange pipe 5 are not particularly limited, but must be set to values that do not cause extremely low heat exchange performance.
The various dimensions of the protrusion 6 include the length La of the upper inclined surface 6a and the length Lb of the lower inclined surface 6b, the angle θa formed by the upper inclined surface 6a and the vertical direction, There are a distance Lc between the upper end and the lower end, a protrusion length H of the protrusion 6, and the like. These dimensions need to be set to values that can smoothly guide frost downward and that the heat exchange performance does not become extremely low. In the present embodiment, since one protrusion 6 is formed corresponding to one heat exchange pipe 5, the distance Lc between the upper end and the lower end of the protrusion 6 is the level of the heat exchange pipe 5. It is set to the same value as the pitch PP.

  As a dimension which prescribes | regulates the positional relationship of the protrusion 6 and the heat exchange pipe 5, there exist the distance W1 which prescribes | regulates the position of a perpendicular direction, and the distance W2 which prescribes | regulates the position of a horizontal direction. The distance W1 is the distance between the lower end of the protrusion 6 and the horizontal straight line c1 passing through the center 5a of the heat exchange pipe 5 located above the lower end. The distance W <b> 2 is a distance between a straight line c <b> 2 connecting the upper end and the lower end of the protrusion 6 and a center line M passing through the center 5 a of each heat exchange pipe 5. These dimensions need to be set to values that mainly prevent the heat exchange performance from becoming extremely low.

  FIG. 3 is a schematic diagram illustrating a defrosting state in the outdoor heat exchanger 2 during the defrosting operation. As shown in FIG. 3A, the air flow inlet side end of the plate fin 3 of the outdoor heat exchanger 2 has a substantially triangular protrusion 6 protruding vertically toward the upstream side of the air flow. Since it is a wave shape formed by arranging a large number, when the outdoor heat exchanger 2 operates as an evaporator, the frost 7 at the end on the inlet side adheres to each of the many protrusions 6. In this way, at the inlet side end where the frost 7 is likely to adhere, the frost 7 separates and adheres to the large number of protrusions 6, so that the defrosting is performed as compared with the case where the frost 7 is clumped and adhered. The frost 7 is easily melted during operation.

  Furthermore, since the upper inclined surface 6a of each of the substantially triangular projections 6 is inclined downward, as shown in FIG. 3 (b), the frost 7 sliding down from the upper side is moved upstream of the air flow. Can be guided and slid down. In particular, in the present embodiment, the substantially triangular protrusion 6 is formed corresponding to each heat exchange pipe 5, and the length La of the upper inclined surface 6a of the protrusion 6 is the length of the lower inclined surface 6b. Since it is formed to be larger than the length Lb, the upper inclined surface 6a can be made relatively long. In this shape, the effect | action which guides the frost 7 which slides down along the inclined surface 6a can be strengthened.

  The frost 7 sliding down from above is smoothly guided and slid down along the inclined surface 6a on the upper side of the projection 6, and finally, as shown in FIG. The frost 7 is removed from the frost and the defrosting is completed.

  FIG. 4 is a cross-sectional view showing another shape of the outdoor heat exchanger. In the outdoor heat exchanger 2a shown in FIG. 4, the distance W1 between the lower end of the protrusion 6 and the horizontal straight line c1 passing through the center 5a of the heat exchange pipe 5 located above the lower end is the room shown in FIG. The length is set shorter than that of the outer heat exchanger 2. Except for the distance W1, it is formed under the same setting conditions as the outdoor heat exchanger 2. Also in the outdoor heat exchanger 2a, defrosting can be performed in the same manner as the outdoor heat exchanger 2.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, since the frost 7 is separated and attached to each protrusion 6 by making the inlet side end portion into a corrugated shape composed of a large number of protrusions 6, the frost 7 is easily melted, Furthermore, the frost 7 can be guided and slid down by the inclined surface 6 a on the upper side of the protrusion 6. Therefore, since the frost 7 can be smoothly slid down, the defrosting time can be shortened.

  (2) In the above embodiment, the substantially triangular protrusion 6 is formed corresponding to each heat exchange pipe 5, and the length La of the upper inclined surface 6a of the protrusion 6 is the lower inclined surface 6b. Therefore, the upper inclined surface 6a can be made relatively long. In this shape, the effect | action which guides the frost 7 which slides down along the inclined surface 6a can be strengthened. Accordingly, the frost 7 sliding down from above can be smoothly guided and slid down along the upper inclined surface 6a, so that the defrosting time can be shortened.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, since 2nd Embodiment changes the structure of the outdoor side heat exchanger 2 of 1st Embodiment, the detailed description is abbreviate | omitted about the same part.

  FIG. 5 is a cross-sectional view showing the configuration of the outdoor heat exchanger 2b used in the second embodiment. Also in this embodiment, the inlet side end portion of the air flow in the plate fin 3 of the outdoor heat exchanger 2 has the protruding portion 6 having a substantially triangular cross section protruding toward the upstream side in the flow direction 4 of the air flow. It is a wave shape formed by arranging a large number in the vertical direction. Specifically, the substantially triangular protrusions 6 are formed so as to be included in a plurality (four in FIG. 5) with respect to the step pitch PP of the heat exchange pipe 5. The inclined surfaces 6a and 6b are formed so that the lengths La and Lb are substantially equal.

The various dimensions of the protrusion 6 and the positional relationship between the protrusion 6 and the heat exchange pipe 5 are not particularly limited as in the first embodiment, but it is necessary to set the values so that the heat exchange performance does not become extremely low. There is.
FIG. 6 is a schematic diagram showing a defrosting state in the outdoor heat exchanger 2b during the defrosting operation. As shown in FIG. 6 (a), the air flow inlet side end of the plate fin 3 of the outdoor heat exchanger 2b has a substantially triangular protrusion 6 protruding vertically toward the air flow upstream side. Since it is a wave shape formed by arranging a large number, when the outdoor heat exchanger 2b operates as an evaporator, the frost 7 at the end on the inlet side adheres to the numerous protrusions 6, respectively. In this way, at the inlet side end portion where the frost 7 is likely to adhere, the frost 7 is separated and attached to the large number of protrusions 6, so that compared with the case where the frost 7 is solidified and attached, FIG. As shown in (b), the frost 7 is easily melted during the defrosting operation. In particular, in the present embodiment, the substantially triangular projections 6 are formed so as to be included with respect to the step pitch PP of the heat exchange pipe 5, and the two inclined surfaces 6 a and 6 b in each projection 6 are formed. Since the lengths La and Lb are substantially equal to each other, it is possible to form a large number of relatively small protrusions 6 having a uniform shape. In this shape, the effect | action which isolate | separates and adheres frost can be strengthened.

  The frost 7 adhering to the large number of protrusions 6 is thus divided and thus melts quickly, and finally the frost 7 is removed from the plate fins 3 as shown in FIG. 6C. Defrosting is complete.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, since the frost 7 is separated and attached to each protrusion 6 by making the inlet side end portion into a corrugated shape composed of a large number of protrusions 6, the frost 7 is easily melted, Therefore, since the frost 7 can be smoothly slid down, the defrosting time can be shortened.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In addition, since 3rd Embodiment changes the structure of the outdoor heat exchanger of 1st Embodiment and 2nd Embodiment, the detailed description is abbreviate | omitted about the same part.

  FIG. 7: is sectional drawing which shows the structure of the outdoor heat exchanger used for 3rd Embodiment of this invention. In the present embodiment, rectangular holes 8 extending in the vertical direction are formed between the heat exchange pipes 5 of the heat exchange pipe array arranged in a plurality of stages in the vertical direction. The rectangular hole 8 is formed on a center line M passing through the center 5 a of each heat exchange pipe 5. An outdoor heat exchanger 2c shown in FIG. 7A is obtained by forming a rectangular hole 8 in the outdoor heat exchanger 2 of the first embodiment, and the outdoor heat exchange shown in FIG. 7B. The vessel 2c is obtained by forming a rectangular hole 8 in the outdoor heat exchanger 2d of the second embodiment.

  By forming the rectangular hole 8 in the plate fin 3, the frost 7 between the heat exchange pipes 5 can be divided. That is, when the frost 7 starts to melt by the defrosting operation, the frost 7 starts to fall downward. At this time, the frost 7 slides down the upstream part and the downstream part of the heat exchange pipe 5 in the plate fin 3, but the frost 7 between the heat exchange pipes 5 is formed upstream and downstream by the rectangular holes 8. It is divided and slides down.

The holes formed between the heat exchange pipes 5 are not limited to the rectangular holes 8 extending in the vertical direction, but may be other shapes such as an elliptical hole or a circular hole extending in the vertical direction.
According to the above embodiment, the outdoor heat exchanger 2c shown in FIG. 7 (a) has the same effect as the first embodiment, and the outdoor heat exchanger 2d shown in FIG. 7 (b) The same effects as those of the second embodiment can be obtained. Furthermore, in the present embodiment, the following effects can be obtained by forming the rectangular holes 8 in the plate fins 3.

  (1) Since the rectangular holes 8 are formed between the heat exchange pipes 5 in the plate fins 3, the temperature around the rectangular holes 8 in the plate fins 3 is higher than that in other parts during the defrosting operation. Therefore, when the frost 7 adhering to the plate fin 3 is melted and slides down by the defrosting operation, the frost 7 is melted and divided around the rectangular hole 8. That is, the frost 7 between the heat exchange pipes 5 is divided by the rectangular holes 8 and slides downward. Thereby, it is suppressed that the frost 7 remains in the upper part of the heat exchange pipe 5, and the plate fin 3 can be defrosted efficiently. Therefore, the defrosting time can be shortened.

  (2) Since the rectangular hole 8 is formed on the center line M passing through the center 5 a of each heat exchange pipe 5, the frost 7 is divided just above the heat exchange pipe 5. As a result, compared with the case where the rectangular hole 8 is formed at a position shifted from the center line M, it is possible to suppress frost from remaining on the upper portion of the heat exchange pipe 5 and to efficiently defrost the plate fins 3. Can do.

  (3) Since the rectangular holes 8 extending in the vertical direction are formed between the heat exchange pipes 5, the frost 7 between the heat exchange pipes 5 as compared with the case where holes of other shapes such as circular holes are formed. Can be promoted. Thereby, it is suppressed that the frost 7 remains in the upper part of the heat exchange pipe 5, and the plate fin 3 can be defrosted efficiently.

In addition, you may change said 1st-3rd embodiment as follows.
In each of the above embodiments, the protrusion 6 has a triangular cross-sectional shape, and the tip of the protrusion 6 and the connecting portion between the protrusions 6 are formed linearly and acutely. The connecting portion between the portions 6 may be formed in an arc shape or a curved shape. The inclined surfaces 6a and 6b are also formed in a straight line shape, but may be formed in an arc shape or a curved shape.

  -The plate fin 3 may be subjected to a surface treatment having water slidability and water repellency. The surface treatment having water slidability and water repellency can be performed by forming a coating film having water slidability and water repellency. By performing the surface treatment having water slidability and water repellency, the frost 7 melted by the defrosting operation can be smoothly slid down and water droplets can be smoothly spilled downward. Thereby, it can suppress that frost and a water droplet remain | survive and can perform the defrost of the plate fin 3 more efficiently. Therefore, the defrosting time can be shortened.

  A waffle fin may be used as the plate fin 3. When waffle fins are used, the wavy shape of the waffle fins promotes the frost 7 and water droplets that have melted down and flow down. Defrosting can be performed more efficiently. Therefore, the defrosting time can be shortened.

  In the above embodiment, the case of the outdoor heat exchanger 2 having the heat exchange pipes 5 of the plurality of stages and one row has been described. However, the same applies to the case of the outdoor heat exchanger having the heat exchange pipes 5 of the plurality of stages and multiple rows. Can be implemented. For example, the same applies to a heat exchanger in which two or more fin rows (see FIG. 1) in which the plate fins 3 are arranged along a direction orthogonal to the air flow direction 4 are arranged. Can do. In this case, the protrusions 6 are formed only at the inlet side end portions of the plate fins 3 in the first fin row, and the protrusions 6 are not formed in the plate fins 3 in the second and subsequent fin rows.

In the above embodiment, the defrosting operation is performed by the reverse method, but the defrosting operation may be performed by the hot gas bypass method.
In the above embodiment, the wave shape formed by arranging a large number of protrusions 6 having a substantially triangular cross section in the vertical direction has been described as the slide accelerating mechanism that promotes the frost sliding during the defrosting operation. It is not limited to the shape. For example, a shape having an inclined surface 6a that guides the frost 7 to the upstream side in the flow direction 4 and slides down, a shape that allows the frost 7 to be separated and attached, and the like are included in the slippage promotion mechanism.

  In each of the above embodiments, a heat pump type air conditioner which is a kind of refrigeration apparatus has been described as an example, but the present invention may be applied to, for example, a refrigerator or a freezer.

  The present invention is an apparatus that requires defrosting such as a home and commercial air conditioner, a domestic and commercial freezer, a domestic and commercial refrigerator, and a domestic and commercial hot water supply device. Useful.

Sectional drawing of the outdoor side heat exchanger 2 used for the air conditioning apparatus 1 which is the 1st Embodiment of this invention. 2 is a refrigerant circuit diagram of the air conditioner 1. FIG. (A)-(c) is a schematic diagram which shows the defrost state in the outdoor side heat exchanger 2 at the time of a defrost operation. Sectional drawing which shows the structure of the outdoor side heat exchanger 2a used for 1st Embodiment. Sectional drawing which shows the structure of the outdoor side heat exchanger 2b used for 2nd Embodiment. (A)-(c) is a schematic diagram which shows the defrost state in the outdoor side heat exchanger 2b at the time of a defrost operation. (A) is sectional drawing which shows the structure of the outdoor side heat exchanger 2c used for 3rd Embodiment, (b) is sectional drawing which shows the structure of the outdoor side heat exchanger 2d. (A)-(d) is a schematic diagram which shows the defrost state in the conventional heat exchanger at the time of a defrost operation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Air conditioning apparatus 2, 2a, 2b, 2c, 2d ... Outdoor heat exchanger, 3 ... Plate fin, 4 ... Flow direction, 5 ... Heat exchange pipe, 5a ... Center, 6 ... Projection, 6a ... Upper side , 6b ... lower slope, 7 ... frost, 8 ... rectangular hole, 9 ... expansion valve, 10 ... indoor heat exchanger, 11 ... four-way switching valve, 12 ... compressor, La ... upper side Length of inclined surface, Lb ... Length of lower inclined surface, M ... Center line, PP ... Step pitch of heat exchange pipe

Claims (9)

A cross fin and tube heat exchanger having fins and a plurality of heat exchange pipes arranged in a vertical direction is used to remove frost attached when the heat exchanger is operated as an evaporator. In the refrigeration apparatus that performs the defrosting operation,
The air flow inlet side end of the fin of the heat exchanger has a corrugated shape in which a number of protrusions having a substantially triangular cross section are arranged in the vertical direction.   The substantially triangular protrusion is formed corresponding to each heat exchange pipe, and the two inclined surfaces of each protrusion have a length of the upper inclined surface larger than that of the lower inclined surface. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is formed as described above.   The substantially triangular projections are formed so as to be included in a plurality with respect to the step pitch of the heat exchange pipe, and are formed so that the lengths of the two inclined surfaces in each projection are substantially equal. The refrigeration apparatus according to claim 1, wherein:   The refrigeration apparatus according to any one of claims 1 to 3, wherein the fin is subjected to a surface treatment having water slidability and water repellency.   The refrigeration apparatus according to claim 1, wherein the fin is a waffle fin.   The said heat exchanger has a hole formed between the heat exchange pipes of the heat exchange pipe row | line | column in the said fin, The refrigeration apparatus of any one of Claims 1-5 characterized by the above-mentioned.   The refrigeration apparatus according to claim 6, wherein the hole is formed on a center line passing through a center of each heat exchange pipe.   The refrigeration apparatus according to claim 6 or 7, wherein the hole is a rectangular hole extending in a vertical direction. A cross fin and tube heat exchanger having fins and a plurality of heat exchange pipes arranged in a vertical direction is used to remove frost attached when the heat exchanger is operated as an evaporator. In the refrigeration apparatus that performs the defrosting operation,
A refrigerating apparatus comprising a sliding acceleration mechanism that promotes frost sliding during a defrosting operation at an end of the air flow inlet side of the fin of the heat exchanger.

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