CN118829842A - Heat exchanger and refrigeration cycle device provided with same - Google Patents

Abstract

The heat exchanger is provided with: a plurality of flat heat transfer tubes each having a flat cross section and having a plurality of refrigerant flow paths therein, the plurality of flat heat transfer tubes being arranged in parallel at intervals; and a plurality of corrugated fins provided between the adjacent flat heat transfer pipes, respectively. The corrugated fin is formed by bending a flat plate-like fin portion into a corrugated shape so as to be juxtaposed in the tube axis direction of the flat heat transfer tube. The fin portion is provided with a louver. A louver having a different structure is provided for each selected fin portion of the plurality of fin portions to vary the amount of frost formed.

Description

Heat exchanger and refrigeration cycle device provided with same

Technical Field

The present invention relates to a heat exchanger and a refrigeration cycle apparatus including the heat exchanger.

Background

Conventionally, for example, a heat exchanger disclosed in patent document 1 has been known which includes a plurality of flat heat transfer tubes arranged in parallel with each other at a distance from each other and a plurality of corrugated fins provided between adjacent flat heat transfer tubes. When such a heat exchanger is used as an evaporator, when the surface temperature of the corrugated fin is lowered, water in the air in the vicinity of the surface of the corrugated fin is analyzed to become condensed water, and when the surface temperature is further below the freezing point, the condensed water is frozen to cause frosting. When frost formation occurs on the surfaces of the corrugated fins, resistance of air passing through the heat exchanger is formed, which is a factor of degrading heat transfer performance of the corrugated fins. Therefore, in the heat exchanger, in order to discharge the condensed water, a slit for discharging the condensed water is provided in the corrugated fin, and the condensed water is discharged through the slit.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2015-183908

Disclosure of Invention

Problems to be solved by the invention

In the heat exchanger disclosed in patent document 1, a plurality of louvers (louver) are provided in each planar portion of the corrugated fin. The corrugated fins increase the heat transfer coefficient by providing the louver plates, and thus promote frosting in the vicinity of the louver plates, and there is a possibility that the air passage may be blocked by the development of the frosting.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a heat exchanger and a refrigeration cycle apparatus including the heat exchanger, which can suppress clogging of a wind path due to frost in a structure including corrugated fins having louvers.

Means for solving the problems

The heat exchanger of the present invention comprises: a plurality of flat heat transfer tubes each having a flat cross section and having a plurality of refrigerant flow paths therein, the plurality of flat heat transfer tubes being arranged in parallel at intervals; and a plurality of corrugated fins provided between the adjacent flat heat transfer tubes, the corrugated fins being formed by bending flat plate-shaped fin portions into a corrugated shape so as to be juxtaposed in a tube axis direction of the flat heat transfer tubes, wherein a louver is provided in each of the fin portions, and wherein the louver having a different structure so as to change a frosting amount is provided in each of the fin portions selected from the plurality of fin portions.

The refrigeration cycle device of the present invention includes the heat exchanger.

Effects of the invention

According to the present invention, since the louver plates having different structures for varying the amount of frost are provided for each selected fin portion among the plurality of fin portions having the louver plates, the fin portions of the louver plates having the structure for reducing the amount of frost can suppress clogging of the air passage, and air can be sent from the upstream side to the downstream side.

Drawings

Fig. 1 is a front view schematically showing a heat exchanger according to embodiment 1.

Fig. 2 is a perspective view schematically showing a main part of the heat exchanger according to embodiment 1.

Fig. 3 is a front view schematically showing a main part of the heat exchanger according to embodiment 1.

Fig. 4 is a front view schematically showing a main part of the heat exchanger of embodiment 1, and is different from fig. 3.

Fig. 5 is an explanatory diagram schematically showing an example of the case where corrugated fins of the heat exchanger of embodiment 1 are manufactured by roll forming.

Fig. 6 is a refrigerant circuit diagram of a refrigeration cycle apparatus including a heat exchanger according to embodiment 1.

Fig. 7 is a plan view schematically showing a main part of the heat exchanger according to embodiment 2.

Fig. 8 is a plan view schematically showing a main part of the heat exchanger according to embodiment 2.

Fig. 9 is a plan view schematically showing a main part of the heat exchanger according to embodiment 3.

Fig. 10 is a plan view schematically showing a main part of the heat exchanger according to embodiment 3.

Fig. 11 is a plan view schematically showing a main part of the heat exchanger according to embodiment 4.

Fig. 12 is a sectional view taken along line A-A of fig. 11.

Fig. 13 is a cross-sectional view taken along line A-A shown in fig. 11 and is a view showing a structure different from that of fig. 12.

Fig. 14 is a graph showing a relationship between a time of condensate water drainage with respect to an inclination angle of the plate portion and a residual water amount remaining on the surface of the fin portion, in the heat exchanger according to embodiment 4.

Fig. 15 is a plan view schematically showing a main part of the heat exchanger according to embodiment 5.

Fig. 16 is a plan view schematically showing a main part of the heat exchanger according to embodiment 5.

Fig. 17 is a plan view schematically showing a main part of a modification of the heat exchanger according to embodiment 5.

Fig. 18 is a plan view schematically showing a main part of a modification of the heat exchanger according to embodiment 5.

Fig. 19 is a plan view schematically showing a main part of the heat exchanger according to embodiment 6.

Fig. 20 is a graph showing a relationship between the size of the fins in the air flow direction and the rate of increase in heating capacity at low temperature.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof is omitted or simplified as appropriate. The configuration described in each drawing may be changed in shape, size, arrangement, and the like as appropriate. In the following description, the upper side in the drawing is referred to as "upper side", and the lower side is referred to as "lower side". For ease of understanding, terms (e.g., "right", "left", etc.) indicating directions are used appropriately, but these terms are for explanation and are not intended to limit the present invention.

Embodiment 1

First, the heat exchanger 100 according to embodiment 1 will be described. Fig. 1 is a front view schematically showing a heat exchanger 100 according to embodiment 1. Fig. 2 is a perspective view schematically showing a main part of the heat exchanger 100 according to embodiment 1. Fig. 3 is a front view schematically showing a main part of the heat exchanger 100 according to embodiment 1.

As shown in fig. 1, a heat exchanger 100 according to embodiment 1 includes: a pair of headers 1 and 2 arranged at a distance from each other in the vertical direction; a plurality of flat heat transfer tubes 3 arranged side by side in the left-right direction with a space therebetween; and a plurality of corrugated fins 4 respectively provided between the adjacent flat heat transfer tubes 3.

The pair of headers 1 and 2 is constituted by an upper header 1 and a lower header 2. The upper header 1 and the lower header 2 are pipes connected to other devices constituting the refrigeration cycle apparatus by pipes, respectively, to which the refrigerant serving as the heat exchange medium flows in and out and which branch or join the refrigerant. The gaseous refrigerant passes through the header 1 on the upper side. The liquid refrigerant passes through the header 2 on the lower side. The plurality of flat heat transfer tubes 3 are arranged in parallel between the upper header 1 and the lower header 2.

The flat heat transfer tube 3 is formed of, for example, an aluminum alloy, and has a flat cross section as shown in fig. 2. The outer surface (flat surface 31) of the flat heat transfer tube 3 on the long side of the flat shape is flat, and the outer surface of the flat shape on the short side is curved. The flat heat transfer tube 3 has a plurality of refrigerant flow paths 30 flowing in the up-down direction inside. The plurality of flat heat transfer tubes 3 are arranged so that the flat surfaces 31 are substantially parallel to each other and stand up in the vertical direction, and the flat surfaces 31 are arranged so as to be substantially perpendicular to the headers 1 and 2. That is, the flat heat transfer tubes 3 are arranged such that the flat surfaces 31 extend along the air flow direction Z. The upper portions of the flat heat transfer tubes 3 are joined by brazing with upper end portions inserted into insertion holes (not shown) formed in the header 1 on the upper side. The lower portions of the flat heat transfer tubes 3 are joined by inserting lower end portions into insertion holes (not shown) of the header 2 formed on the lower side and brazing. The refrigerant flow path 30 of the flat heat transfer tube 3 extends in the up-down direction and communicates with the upper header 1 and the lower header 2. As the solder for brazing, for example, a solder containing aluminum is used.

The corrugated fins 4 are formed of, for example, an aluminum alloy, and are provided to enlarge a heat transfer area between the refrigerant flowing through the refrigerant flow path 30 of the flat heat transfer tube 3 and the outside air. The corrugated fins 4 and the flat heat transfer tubes 3 form ventilation paths through which air flows. As shown in fig. 1 and 2, the corrugated fin 4 is formed in the following manner: the flat plate-shaped fin material is corrugated, and is formed by bending the fin material by repeating the bending of mountain and valley folds to form a wave shape. Further, a solder layer mainly made of a solder containing aluminum of aluminum-silicon type is coated on the surface of the fin material, for example. The corrugated fin 4 has a plate thickness of, for example, about 50 μm to 200 μm.

The corrugated fin 4 has a flat plate-like fin portion 40 and top portions 41 formed at both ends of the fin portion 40. The top 41 is a bent portion formed by the irregularities generated by the wave formation. The corrugated fins 4 are provided between two flat heat transfer tubes 3 adjacent to each other among the plurality of flat heat transfer tubes 3 in such a manner that the waveforms are connected in the tube axis direction Y of the flat heat transfer tubes 3. That is, as shown in fig. 1, the corrugated fins 4 are arranged such that the fin portions 40 are alternately inclined in opposite directions when viewed from the air flow direction Z. The bent top portions 41 of the corrugated fins 4 are in surface contact with the flat surfaces 31 of the two flat heat transfer tubes 3, and joined by brazing.

As shown in fig. 2, a plurality of louvers 5 are provided in the fin portion 40 of the corrugated fin 4. The louver 5 is provided to increase the heat transfer coefficient between the refrigerant flowing through the refrigerant flow path 30 of the flat heat transfer tube 3 and the outside air. The louver 5 includes a slit 5a through which air passes and a plate portion 5b inclined in the up-down direction to guide the air to the slit 5a. The slit 5a is formed in a rectangular shape long in the parallel direction X of the flat heat transfer tubes 3. In general, a punched portion is cut up to become the plate portion 5b when the slit 5a is formed. Therefore, the plate portion 5b is formed in a rectangular shape in accordance with the shape of the slit 5a. The louvers 5 are provided in a plurality of slits 5a provided along the tube axis direction Y of the flat heat transfer tube 3. The louvers 5 are juxtaposed in the air flow direction Z, i.e., in the depth direction of the fin portion 40. That is, the louvers 5 are juxtaposed along the air flow. The shape and size of the slit 5a and the plate portion 5b are not limited to the configuration shown in the drawings. The louver 5 may be provided in some of the plurality of fin portions 40 or in all of the fin portions 40.

Further, drain holes 6 for draining the condensed water W flowing on the upper surface of the fin portion 40 are formed in the fin portion 40. The drain hole 6 may be provided in some of the plurality of fin portions 40 or in all of the fin portions 40. The shape, number, arrangement, and the like of the drain holes 6 are examples, and are not limited to the configuration shown in the drawings.

Here, when the heat exchanger 100 is used as a condenser, a high-temperature and high-pressure refrigerant flows through the refrigerant flow path 30 of the flat heat transfer tube 3. On the other hand, when the heat exchanger 100 is used as an evaporator, a low-temperature and low-pressure refrigerant flows through the refrigerant flow path 30 of the flat heat transfer tube 3. When the heat exchanger 100 is used as an evaporator, as indicated by an arrow in fig. 1, the refrigerant flows into the lower header 2 through the inlet pipe 10 that supplies the refrigerant from an external device (not shown) to the heat exchanger 100. The refrigerant flowing into the header 2 on the lower side is distributed to the flat heat transfer tubes 3, and passes through the refrigerant flow paths 30 of the flat heat transfer tubes 3. The flat heat transfer tube 3 exchanges heat between the refrigerant passing through the refrigerant flow path 30 and the outside air passing outside the tube. At this time, the refrigerant absorbs heat from the outside air while passing through the refrigerant flow path 30. The refrigerant having exchanged heat through the refrigerant flow paths 30 of the flat heat transfer tubes 3 flows into the header 1 on the upper side and merges. The refrigerant that merges inside the upper header 1 flows back to an external device (not shown) through the outlet pipe 11 connected to the upper header 1.

When the heat exchanger 100 is used as an evaporator, water in the air in the vicinity of the surface of the fin portion 40 is analyzed to become condensed water W when the surface temperature of the fin portion 40 is lowered, and the condensed water W is frozen to cause frosting when the surface temperature is further below the freezing point. Here, in general, in the heat exchanger 100, the amount of heat exchange is large on the upstream side of the air passage where the temperature difference between the air and the fin portion 40 is large, and therefore, the amount of condensed water W generated on the surface of the fin portion 40 is also large on the upstream side of the air passage. Further, according to the analysis and experiments of the inventors, there are the following problems: the fin portion 40 has a large amount of condensed water W at a portion where the louver 5 is formed, which has a high heat transfer coefficient, and the gaps between adjacent louvers 5 are easily clogged with frost when frosting occurs, and the frosting endurance is small. Frosting endurance means that heating capacity is large with respect to an operation time under low temperature conditions. That is, by providing the heat exchanger 100 with a structure having a large frost resistance, performance degradation due to frost clogging can be suppressed with respect to the operating time. Incidentally, in the fin portion 40 where the louver 5 is not provided, clogging of the air passage due to frost is less likely to occur, and thus the frost resistance is high.

Therefore, in the heat exchanger 100 according to embodiment 1, as shown in fig. 3, the louver 5A and the louver 5B having different structures for changing the amount of frost are provided for each selected fin portion 40 among the plurality of fin portions 40. The louvers 5A and 5B having different structures have different width dimensions in the parallel direction X of the flat heat transfer tubes 3. The louvers 5A and 5B of different structures are formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Specifically, the heat exchanger 100 shown in fig. 3 has the following structure: the fin portions 40A and the fin portions 40B are alternately arranged along the tube axis direction Y of the flat heat transfer tubes 3, the fin portions 40A are formed with a plurality of louvers 5A having a long width dimension in the parallel direction X of the flat heat transfer tubes 3, and the fin portions 40B are formed with a plurality of louvers 5B having a short width dimension in the parallel direction X of the flat heat transfer tubes 3. As a result, as shown in fig. 3, when the heat exchanger 100 is viewed from the upstream side in the air flow direction Z, a low frost formation space S is formed on both sides of the louver 5B having a short width.

As shown in fig. 3, when the heat exchanger 100 is viewed from the upstream side in the air flow direction Z, the fin portions 40A and 40B are linear. The inclined surfaces of the louvers 5A and 5B may be regarded as portions extending upward and downward from the linear portions of the fin portions 40A and 40B. In the heat exchanger 100, air flows parallel to the surfaces of the fin portions 40A and 40B, and when the air collides with the louvers 5A and 5B extending upward and downward to exchange heat, water vapor contained in the air is cooled to become condensed water W, and is frozen to become frost. Therefore, when the louvers 5A and 5B are viewed from the upstream side in the air flow direction Z, the larger the areas of the louvers 5A and 5B protruding upward and downward from the surfaces of the fin portions 40A and 40B, the larger the amount of frost. In general, the total of the projected areas of the louvers 5A and 5B in each of the fin portions 40A and 40B is calculated, and the fin portion having the larger total of the projected areas of the louvers 5A is the fin portion 40A formed with the louver 5A having the larger amount of frost. The fin portion having a small total protruding area of the louver 5B is the fin portion 40B of the louver 5B having a structure with a small amount of frost.

In the heat exchanger 100 according to embodiment 1, the fin portion 40A having the plurality of louvers 5A having a large amount of frost and the fin portion 40B having the plurality of louvers 5B having a smaller amount of frost are periodically repeated in the tube axis direction Y of the flat heat transfer tube 3. As a result, as shown in fig. 3, when the heat exchanger 100 is viewed from the upstream side in the air flow direction Z, there is a low frost formation space S in which frost formation is unlikely to occur, and therefore, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side, and therefore, frost resistance can be improved.

The heat exchanger 100 according to embodiment 1 may include the fin portion 40 having no louver 5 among the plurality of fin portions 40. In the fin portion 40 without the louver 5, frost is less likely to occur, and therefore, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side.

Fig. 4 is a front view schematically showing a main part of the heat exchanger 100 according to embodiment 1, and is different from fig. 3. As shown in fig. 4, the heat exchanger 100 according to embodiment 1 may be configured such that two fin portions 40, which are continuous in the tube axis direction Y, among the plurality of fin portions 40 are provided in 1 group, and the louvers 5A and the louvers 5B having different width dimensions in the parallel direction X of the flat heat transfer tubes 3 are provided in the group. Although not shown, the heat exchanger 100 according to embodiment 1 may include three or more fin portions 40 that are continuous in the tube axis direction Y among the plurality of fin portions 40 as 1 group, or may include other combinations. In addition, three or more types of louvers 5 having different structures may be provided for each selected fin portion 40. In the above case, the louvers 5 of different structures are also formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Fig. 5 is an explanatory diagram schematically showing an example of the case where the corrugated fin 4 of the heat exchanger 100 of embodiment 1 is manufactured by roll forming. The corrugated fin 4 is produced by passing the fin material 7 between the corrugated cutters 80 arranged vertically. The wave cutter 80 may use different sizes of blades, for example, for the blade 80a and the blade 80 b. By adjusting the arrangement pattern of the blades 80a and the blades 80B of the corrugate fin 4, as shown in fig. 3 and 4, it is possible to form the louvers 5A and 5B having different width dimensions in the parallel direction X of the flat heat transfer tubes 3. The louvers 5A and 5B having different structures may be irregularly arranged along the tube axis direction Y of the flat heat transfer tube 3, but, as shown in fig. 4, it is preferable to periodically form the louvers along the tube axis direction Y of the flat heat transfer tube 3, considering that the corrugated fins 4 are generally produced by roll forming.

Next, an example of the refrigeration cycle apparatus 200 including the heat exchanger 100 having the above-described structure will be described with reference to fig. 6. Fig. 6 is a refrigerant circuit diagram of the refrigeration cycle apparatus 200 including the heat exchanger 100 according to embodiment 1. In embodiment 1, an air conditioner will be described as an example of the refrigeration cycle apparatus 200.

As shown in fig. 6, in the refrigeration cycle apparatus 200 according to embodiment 1, an outdoor unit 201 and an indoor unit 202 are connected by a gas refrigerant pipe 300 and a liquid refrigerant pipe 301 to form a refrigerant circuit. The outdoor unit 201 includes a compressor 203, a flow path switching device 204, an outdoor heat exchanger 205, and an outdoor fan 206. The indoor unit 202 includes an expansion mechanism 207, an indoor heat exchanger 208, and an indoor fan 209. The refrigerant circuit is configured by sequentially connecting a gas refrigerant pipe 300 and a liquid refrigerant pipe 301 to a compressor 203, a flow switching device 204, an outdoor side heat exchanger 205, an expansion mechanism 207, and an indoor side heat exchanger 208.

The heat exchanger 100 described in embodiment 1 is mainly used as the outdoor side heat exchanger 205. The heat exchanger 100 described in embodiment 1 may be used as the indoor heat exchanger 208, or may be used as both the outdoor heat exchanger 205 and the indoor heat exchanger 208. In the refrigeration cycle apparatus 200 shown in the drawing, 1 outdoor unit 201 and 1 indoor unit 202 are connected by a gas refrigerant pipe 300 and a liquid refrigerant pipe 301. However, the number of the outdoor units 201 and the indoor units 202 is not limited to 1.

The compressor 203 compresses the sucked refrigerant to be in a high-temperature and high-pressure state and discharges the refrigerant. As an example, the compressor 203 is a positive displacement compressor configured to be capable of varying an operation capacity and driven by a motor controlled by an inverter.

As an example, the flow path switching device 204 is a four-way valve, and has a function of switching the flow path of the refrigerant. The flow path switching device 204 switches the refrigerant flow path during the cooling operation so as to connect the refrigerant discharge side of the compressor 203 to the gas side of the outdoor side heat exchanger 205 and to connect the refrigerant suction side of the compressor 203 to the gas side of the indoor side heat exchanger 208. On the other hand, the flow path switching device 204 switches the refrigerant flow path during the heating operation so as to connect the refrigerant discharge side of the compressor 203 to the gas side of the indoor side heat exchanger 208 and to connect the refrigerant suction side of the compressor 203 to the gas side of the outdoor side heat exchanger 205. The flow path switching device 204 may be configured by combining a two-way valve or a three-way valve.

The outdoor heat exchanger 205 functions as an evaporator during the heating operation, and exchanges heat between the refrigerant flowing out from the expansion mechanism 207 and flowing inside and the outdoor air. The outdoor heat exchanger 205 functions as a condenser during the cooling operation, and exchanges heat between the refrigerant discharged from the compressor 203 and flowing inside and the outdoor air. The outdoor heat exchanger 205 sucks in outdoor air by an outdoor fan 206, and discharges air, which has exchanged heat with the refrigerant, to the outside.

The expansion mechanism 207 decompresses and expands the refrigerant flowing out of the condenser, and is constituted by an electronic expansion valve capable of adjusting the opening degree of the throttle, for example. The expansion mechanism 207 controls the pressure of the refrigerant flowing into the outdoor heat exchanger 205 or the indoor heat exchanger 208 by adjusting the opening degree.

The indoor heat exchanger 208 functions as a condenser during the heating operation, and exchanges heat between the indoor air and the refrigerant discharged from the compressor 203 and flowing therein. The indoor heat exchanger 208 functions as an evaporator during the cooling operation, and exchanges heat between the indoor air and the refrigerant flowing out of the expansion mechanism 207 and flowing therein. The indoor heat exchanger 208 sucks in indoor air by an indoor fan 209 and supplies air, which has exchanged heat with the refrigerant, into the room.

Next, the operation of the refrigeration cycle apparatus 200 during the heating operation will be described. In the heating operation, the flow path switching device 204 is switched to the broken line side in fig. 6. The high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 203 flows into the indoor heat exchanger 208 through the flow switching device 204. The gas refrigerant flowing into the indoor heat exchanger 208 exchanges heat with air in the space to be conditioned sent from the indoor fan 209, and is condensed and liquefied. The liquefied refrigerant is decompressed by the expansion mechanism 207, becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, and then flows into the outdoor heat exchanger 205. The liquid refrigerant flowing into the outdoor heat exchanger 205 exchanges heat with the outdoor air sent from the outdoor fan 206, and evaporates and gasifies. The vaporized refrigerant passes through the flow path switching device 204 and is again sucked into the compressor 203.

Next, the operation of the refrigeration cycle apparatus 200 during the cooling operation will be described. In the cooling operation, the flow path switching device 204 is switched to the solid line side in fig. 6. The high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 203 flows into the outdoor heat exchanger 205 through the flow switching device 204. The gas refrigerant flowing into the outdoor heat exchanger 205 exchanges heat with the outdoor air sent from the outdoor fan 206, and is condensed and liquefied. The liquefied refrigerant is decompressed by the expansion mechanism 207, becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, and then flows into the indoor heat exchanger 208. The liquid refrigerant flowing into the indoor heat exchanger 208 exchanges heat with air in the space to be air-conditioned sent from the indoor fan 209, and evaporates and gasifies. The vaporized refrigerant passes through the flow path switching device 204 and is again sucked into the compressor 203.

Embodiment 2

Next, a heat exchanger 101 according to embodiment 2 will be described with reference to fig. 7 and 8. Fig. 7 and 8 are plan views schematically showing main portions of the heat exchanger 101 according to embodiment 2. The same reference numerals are given to the same components as those of the heat exchanger 100 described in embodiment 1, and the description thereof is omitted appropriately.

As shown in fig. 7 and 8, the heat exchanger 101 according to embodiment 2 is configured such that the number of louvers 5 provided in one fin portion 40 is different for each selected fin portion 40 among the plurality of fin portions 40. The different numbers of louvers 5 are formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Specifically, the heat exchanger 101 according to embodiment 2 has the following structure: the fin portions 40A having a large number of louvers 5 shown in fig. 7 and the fin portions 40B having a small number of louvers 5 shown in fig. 8 are alternately arranged along the tube axis direction Y of the flat heat transfer tube 3. In the fin portion 40B in which the number of louvers 5 is small, the heat transfer coefficient by the louvers 5 is small, and therefore, the amount of frost is reduced, and a low frost formation space can be formed. In this way, in the heat exchanger 100 according to embodiment 2, by providing the fin portions 40B having a small number of louver plates 5, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side, so that frost resistance can be improved. The number of louvers 5 is not limited to the number shown in the figure, and may be appropriately changed according to the performance of the heat exchanger 101.

The heat exchanger 101 of embodiment 2 may include the fin portion 40 having no louver 5 among the plurality of fin portions 40. In the fin portion 40 without the louver 5, frost is less likely to occur, and therefore, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side.

Although not shown, the heat exchanger 101 according to embodiment 2 may be configured such that 1 group of two fin portions 40 continuous in the tube axis direction Y among the plurality of fin portions 40 is provided with louvers 5 having different structures. Although not shown, three or more fin portions 40 among the plurality of fin portions 40 that are continuous in the tube axis direction Y of the flat heat transfer tube 3 may be set as 1 group, or may be combined. In addition, 3 or more different types of louvers 5 may be provided for each selected fin portion 40. In the above case, a different number of louvers 5 are also formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

The heat exchanger 101 according to embodiment 2 may be combined with the features of the heat exchanger 100 described in embodiment 1.

Embodiment 3

Next, the heat exchanger 102 according to embodiment 3 will be described with reference to fig. 9 and 10. Fig. 9 and 10 are plan views schematically showing main portions of the heat exchanger 102 according to embodiment 3. The same reference numerals are given to the same components as those of the heat exchanger 100 and the heat exchanger 101 described in the above-described embodiment 1 and embodiment 2, and the description thereof will be omitted appropriately.

As shown in fig. 9 and 10, the heat exchanger 102 according to embodiment 3 is configured such that the positions of the louver 50 and the louver 51 provided on the most upstream side of the air passage are different for each selected fin portion 40 of the plurality of fin portions 40. The louvers 50 and 51 of different structures are formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Specifically, the louver 50 provided on the most upstream side of the air passage of the fin portion 40A shown in fig. 9 is formed at a position that is a distance L1 from the upstream side end portion of the flat heat transfer tube 3 toward the downstream side. The louver 51 provided on the most upstream side of the air passage of the fin portion 40B shown in fig. 10 is formed at a position distant from the upstream end portion of the flat heat transfer tube 3 by a distance L2 toward the downstream. The relationship between the distance L1 and the distance L2 is L1 > L2. The fin portions 40A having the louvers 50 and the fin portions 40B having the louvers 51 are alternately arranged along the tube axis direction Y of the flat heat transfer tube 3.

By forming the louver 50 provided on the most upstream side of the air passage at a position distant downstream from the upstream end of the flat heat transfer tube 3 as in the fin portion 40A shown in fig. 9, air is smoothly heat-exchanged on the surface of the fin portion 40A upstream of the louver 50, and frost can be uniformly formed. In the fin portion 40A, the amount of water condensed in the vicinity of the louver 50 provided on the most upstream side of the air passage is small, and therefore, frost formation is reduced, and a low frost formation space can be formed. In this way, in the heat exchanger 100 according to embodiment 3, since the louver 50 provided on the most upstream side of the air passage is provided at the fin portion 40A formed at a position distant downstream from the upstream end portion of the flat heat transfer tube 3, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side, so that frost resistance can be improved. The number of the louvers 5 is not limited to the number shown in the drawings, and is appropriately changed according to the performance of the heat exchanger 102.

The heat exchanger 102 of embodiment 3 may include the fin portion 40 having no louver 5 among the plurality of fin portions 40. In the fin portion 40 without the louver 5, frost is less likely to occur, and therefore, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side.

Although not shown, the heat exchanger 102 according to embodiment 3 may include 1 group of two fin portions 40, among the plurality of fin portions 40, which are continuous in the tube axis direction Y of the flat heat transfer tube 3, and may be provided with louvers 5 having different structures for each group. Although not shown, three or more fin portions 40 among the plurality of fin portions 40 that are continuous in the tube axis direction Y of the flat heat transfer tube 3 may be set as 1 group, or may be combined. In addition, 3 or more types of louvers 5 having different structures may be provided for each selected fin portion 40. In the above case, the louvers 5 of different structures are also formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

The heat exchanger 100 according to embodiment 3 may be combined with the features of the heat exchanger 100 and the heat exchanger 101 described in embodiment 1 and embodiment 2.

Embodiment 4

Next, the heat exchanger 103 according to embodiment 4 will be described with reference to fig. 11 to 14. Fig. 11 is a plan view schematically showing a main part of the heat exchanger 103 according to embodiment 4. Fig. 12 is a sectional view taken along line A-A of fig. 11. Fig. 13 is a cross-sectional view taken along line A-A shown in fig. 11 and is a view showing a structure different from that of fig. 12. The same reference numerals are given to the same constituent elements as those of the heat exchangers 100 to 102 described in the above embodiments 1 to 3, and the description thereof will be omitted appropriately.

As shown in fig. 11 to 13, the heat exchanger 103 according to embodiment 4 is configured such that the inclination angle θ of the plate portion 5b of the louver 5 is different for each selected fin portion 40 among the plurality of fin portions 40. The louvers 5 of different structures are formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Specifically, the heat exchanger 103 according to embodiment 4 has the following structure: the fin portions 40A and 40B are alternately arranged along the tube axis direction Y of the flat heat transfer tube 3, the fin portions 40A are formed with the louver 52 having the small inclination angle θ1 of the plate portion 5B as shown in fig. 12, and the fin portions 40B are formed with the louver 53 having the large inclination angle θ2 of the plate portion 5B as shown in fig. 13. Arrows B shown in fig. 12 and 13 indicate the flow of air through the slit 5 a. The inclination directions of the plate portion 5b formed on the upstream side of the air passage with respect to the drain hole 6 and the plate portion 5b formed on the downstream side of the air passage with respect to the drain hole 6 are opposite to each other, but may be the same.

In the fin portion 40A of the louver 52 having the small inclination angle θ1 of the plate portion 5b, the heat transfer coefficient at the louver 52 can be suppressed as compared with the fin portion 40A of the louver 53 having the large inclination angle θ2 of the plate portion 5b, and therefore, frosting is reduced, and a low frosting space can be formed. In this way, in the heat exchanger 100 according to embodiment 4, the fin portion 40A having the louver 52 with the small inclination angle θ1 of the plate portion 5b is provided, so that clogging of the air passage can be suppressed for a long period of time, and air can be sent from the windward side to the downstream side, and thus frost resistance can be improved.

Fig. 14 is a graph showing the relationship between the time of draining condensed water W at an inclination angle θ with respect to the plate portion 5b and the amount of residual water remaining on the surface of the fin portion 40 in the heat exchanger 103 of embodiment 4. The horizontal axis of fig. 14 represents time. The vertical axis of fig. 14 represents the residual water amount. The inclination angle θ of the plate portion 5b indicates 15 °,20 °,30 °, 40 °, respectively. Fig. 14 is a graph showing that the smaller the residual water amount in a short time, the better the drainage. In the heat exchanger 103, if the inclination angle θ of the plate portion 5b is too small, there is a possibility that the drainage will be deteriorated and the residual water will be refrozen. As a result, there occurs a phenomenon that frosting becomes large and frosting endurance becomes poor. According to the experiments and analyses of the inventors, in order to improve frosting endurance while considering drainage, the louver 5 is preferably formed such that the inclination angle θ of the plate portion 5b is in the range of 20 ° or more and θ or less than 40 °. For example, in the case shown in fig. 12 and 13, the inclination angle θ1 and the inclination angle θ2 of the plate portion 5b may be 20 ° +.θ1 < θ2+.40.

The heat exchanger 103 according to embodiment 4 may include the fin portion 40 having no louver 5 among the plurality of fin portions 40. In the fin portion 40 without the louver 5, frost is less likely to occur, and therefore, clogging of the air passage can be suppressed for a long period of time, and air can be sent from the upstream side to the downstream side.

Although not shown, the heat exchanger 103 according to embodiment 4 may include 1 group of two fin portions 40 continuous in the tube axis direction Y of the flat heat transfer tube 3, among the plurality of fin portions 40, and may be provided with louvers 5 having different structures for each group. Although not shown, three or more fin portions 40 among the plurality of fin portions 40 that are continuous in the tube axis direction Y of the flat heat transfer tube 3 may be set as 1 group, or may be combined. In addition, 3 or more types of louvers 5 having different structures may be provided for each selected fin portion 40. In the above case, the louvers 5 of different structures are also formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

The heat exchanger 103 according to embodiment 4 may be combined with the features of the heat exchangers 100 to 102 described in embodiments 1 to 3.

Embodiment 5

Next, the heat exchanger 104 according to embodiment 5 will be described with reference to fig. 15 and 16. Fig. 15 and 16 are plan views schematically showing main portions of the heat exchanger 104 according to embodiment 5. The same reference numerals are given to the same constituent elements as those of the heat exchangers 100 to 103 described in embodiments 1 to 4, and the description thereof will be omitted appropriately.

As shown in fig. 15 and 16, in the heat exchanger 104 according to embodiment 5, the drain holes 6 having different structures for changing the amount of frost are provided for each selected fin portion 40 among the plurality of fin portions 40. The drain holes 6 of different structures are different in total area of openings of the drain holes 6 formed in one fin portion 40. The drain holes 6 of different structures are formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Specifically, the heat exchanger 104 according to embodiment 5 has the following structure: the fin portions 40A having a small total area of the openings of the plurality of drain holes 6 shown in fig. 15 and the fin portions 40B having a large total area of the openings of the plurality of drain holes 6 shown in fig. 16 are alternately arranged along the tube axis direction Y of the flat heat transfer tube 3. As shown in fig. 15, in the fin portion 40A having a small total area of openings of the drain holes 6, two drain holes 6 having the same shape and the same size are formed in an aligned manner along the air flow direction Z, for example. As shown in fig. 16, in the fin portion 40B having a large total area of openings of the drain holes 6, four drain holes 6 having the same shape and the same size are formed, for example, in two rows in the air flow direction Z and the parallel direction X of the flat heat transfer tubes 3.

In the fin portion 40B having a large total area of the openings of the drain holes 6, the drain speed of the condensed water W is high, and therefore the amount of residual water is small, and the condensed water W on the surface is less likely to freeze even under low temperature conditions. In addition, in the heat exchanger 104, the heat transfer coefficient of the fin portion 40B is reduced by the drain hole 6, so that a low frost formation space in which frost is less likely to develop is formed around the drain hole 6, and the frost resistance can be improved. Further, the fin portions 40B between the adjacent drain holes 6 serve as water guide areas for the condensed water W, and the condensed water W flows down the water guide areas to the drain holes 6, so that the drainage is improved.

The shape, number, and arrangement of the drain holes 6 are not limited to the configuration shown in the drawings. For example, drain holes 6 having different shapes may be formed in the same fin portion 40. The louver 5 of the heat exchanger 104 according to embodiment 5 is configured to apply the configurations described in embodiments 1 to 4.

Although not shown, the heat exchanger 104 according to embodiment 5 may have 1 group of two fin portions 40 that are continuous in the tube axis direction Y of the flat heat transfer tube 3, among the plurality of fin portions 40, and drain holes 6 having different structures may be provided in the group. Although not shown, three or more fin portions 40 among the plurality of fin portions 40 that are continuous in the tube axis direction Y of the flat heat transfer tube 3 may be set as 1 group, or may be combined. In addition, 3 or more kinds of drain holes 6 having different structures may be provided for each selected fin portion 40. In the above case, the drain holes 6 of different structures are also formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Fig. 17 and 18 are plan views schematically showing main portions of a modification of the heat exchanger 104 according to embodiment 5. In the heat exchanger 104A shown in fig. 17 and 18, the drain holes 6 having different opening areas are provided for each selected fin portion 40 of the plurality of fin portions 40. In the heat exchanger 104A shown in fig. 17 and 18, one drain hole 6 is formed in each fin portion 40. The drain holes 6 of different structures are formed periodically along the tube axis direction Y of the flat heat transfer tube 3.

Specifically, the heat exchanger 104A has the following structure: the fin portions 40A having a small opening area of the drain hole 60 shown in fig. 17 and the fin portions 40B having a large opening area of the drain hole 61 shown in fig. 18 are alternately arranged along the tube axis direction Y. In the heat exchanger 104A shown in fig. 17 and 18, the drain rate of the condensed water W is high in the fin portion 40B having a large opening area of the drain hole 61, and therefore the residual water amount is small, and the condensed water W on the surface is less likely to freeze even under low temperature conditions. In addition, in the heat exchanger 104A, the heat transfer coefficient of the fin portion 40B is reduced by the drain hole 61, so that a low frost formation space in which frost is less likely to develop is formed around the drain hole 61, and the frost resistance can be improved. The shape and arrangement of the drain holes 60 and 61 are examples, and are not limited to the configuration shown in the drawings.

Embodiment 6

Next, the heat exchanger 105 according to embodiment 6 will be described with reference to fig. 19 and 20. Fig. 19 is a plan view schematically showing a main part of the heat exchanger 105 according to embodiment 6. The same reference numerals are given to the same constituent elements as those of the heat exchangers 100 to 104 described in embodiments 1 to 5, and the description thereof will be omitted appropriately.

As shown in fig. 19, the heat exchanger 105 according to embodiment 6 has a structure in which 2 rows of flat heat transfer tubes 3 are arranged along the air flow direction Z. The flat heat transfer tube 3 is constituted by a flat heat transfer tube 3A disposed on the upstream side of the air passage and a flat heat transfer tube 3B disposed on the downstream side of the air passage. The flat heat transfer tubes 3 are not limited to the 2 rows shown in the figure, but may be arranged in 3 or more rows along the air flow direction Z. The louver 5 or the drain hole 6 having the structure described in embodiments 1 to 5 is applied to the fin portion 40. In general, in the heat exchanger 105, the amount of frost formed on the fin portion 40 surrounded by the flat heat transfer tube 3B on the downstream side of the air passage is smaller than the fin portion 40 surrounded by the flat heat transfer tube 3A on the upstream side of the air passage, and a low frost formation space is formed. Therefore, by applying the structure described in embodiments 1 to 5 to the fin portion 40 surrounded by the flat heat transfer tube 3A on the upstream side of the air passage, the heat exchanger 105 can suppress clogging of the air passage for a long period of time in the fin portion 40 on the upstream side and the downstream side of the air passage, and can convey air from the upstream side to the downstream side, so that the frost resistance can be improved.

Fig. 20 is a graph showing a relationship between the size of the fin portion 40 in the air flow direction Z and the heating capacity improvement rate at low temperature. The horizontal axis of fig. 20 shows the dimensions of the fin portion 40 in the air flow direction Z. The vertical axis of fig. 20 shows the rate of improvement in heating capacity at low temperature. In the heat exchanger 105, as shown in fig. 20, it is understood that the longer the fin portion 40 in the air flow direction Z is, the higher the heating capacity at low temperature is. Further, according to experiments and analyses by the inventors, it was confirmed that the fin portion 40 was particularly effective by having the length L3 of 22mm or more in the air flow direction Z as shown in fig. 19.

The heat exchanger 100 and the refrigeration cycle apparatus 200 have been described above based on the embodiments, but the present invention is not limited to the configuration of the above embodiments. For example, the heat exchangers (100 to 105) and the refrigeration cycle apparatus 200 are not limited to the illustrated configuration, and may include other components. In short, the heat exchangers (100 to 105) and the refrigeration cycle apparatus 200 include the range of design changes and application changes that are generally performed by those skilled in the art, without departing from the technical spirit thereof.

Description of the reference numerals

1.2 Headers, 3A, 3B flat heat transfer tubes, 4 corrugated fins, 5A, 5B louvers, 5A slits, 5B plate portions, 6 drain holes, 7 fin materials, 10 inlet piping, 11 outlet piping, 30 refrigerant flow passages, 31 flat surfaces, 40A, 40B fin portions, 41 tops, 50, 51, 52, 53 louvers, 60, 61 drain holes, 80 corrugated cutters, 80A, 80B blades, 100, 101, 102, 103, 104A, 105 heat exchangers, 200 refrigeration cycle devices, 201 outdoor units, 202 indoor units, 203 compressors, 204 flow passage switching devices, 205 outdoor side heat exchangers, 206 outdoor side fans, 207 expansion mechanisms, 208 indoor side heat exchangers, 209 indoor side fans, 300 gas refrigerant piping, 301 liquid refrigerant piping, S low frost spaces, X parallel directions, Y pipe axis directions, Z flow directions, W.

Claims (10)

1. A heat exchanger, wherein the heat exchanger comprises:

A plurality of flat heat transfer tubes each having a flat cross section and having a plurality of refrigerant flow paths therein, the plurality of flat heat transfer tubes being arranged in parallel at intervals; and

A plurality of corrugated fins provided between adjacent ones of the flat heat transfer tubes, respectively,

The corrugated fin is formed by bending a flat plate-shaped fin portion into a corrugated shape so as to be juxtaposed in the tube axis direction of the flat heat transfer tube,

A louver board is arranged on the fin part,

The louver plates having different structures so as to vary the amount of frost formed are provided for each selected fin portion of the plurality of fin portions.

2. The heat exchanger of claim 1, wherein,

The louver plates of different structures are formed periodically along the tube axis direction of the flat heat transfer tube.

3. A heat exchanger according to claim 1 or 2, wherein,

The louver plates of different structures have different width dimensions in the parallel direction of the flat heat transfer tubes.

4. A heat exchanger according to any one of claims 1 to 3 wherein,

The louver plates of different structures have different numbers of louver plates provided in one fin portion.

5. The heat exchanger according to any one of claims 1 to 4, wherein,

The louver has a slit through which air passes and a plate portion inclined with respect to the fin portion to guide the air toward the slit,

The louver boards of different structures have different inclination angles of the board portions.

6. The heat exchanger according to any one of claims 1 to 5, wherein,

The fin portions without the louver are included in the plurality of fin portions.

7. The heat exchanger according to any one of claims 1 to 6, wherein,

A drain hole for draining water flowing on the upper surface of the fin part is formed on the fin part,

The fin portion selected for each of the plurality of fin portions is provided with a drain hole having a different structure so as to vary the amount of frost formed.

8. The heat exchanger of claim 7, wherein,

The drain holes of different structures are different in total area of openings of the drain holes formed in one of the fin portions.

9. The heat exchanger according to any one of claims 1 to 8, wherein,

The fin portion has a dimension of 22mm or more in the air flow direction.

10. A refrigeration cycle apparatus, wherein,

The refrigeration cycle apparatus includes the heat exchanger according to any one of claims 1 to 9.