JP7678874B2 - Air conditioner indoor unit - Google Patents

Description

The present disclosure relates to the structure of an indoor unit of an air conditioning device equipped with flat heat transfer tubes.

A heat exchanger installed as an indoor unit of an air conditioner functions as an evaporator during cooling operation. In recent years, in order to realize refrigerant saving, a heat exchanger composed of flat heat transfer tubes is used as a heat exchanger of an indoor unit. For example, as shown in FIG. 2 of Patent Document 1, a heat exchanger composed of flat heat transfer tubes includes a plurality of flat heat transfer tubes extending horizontally, a plurality of heat transfer fins attached in contact with the flat heat transfer tubes, a plurality of refrigerant headers arranged at both ends of the flat heat transfer tubes to distribute refrigerant to the flat heat transfer tubes or to merge refrigerant from the flat heat transfer tubes, and a plurality of connecting pipes to flow refrigerant into and out of the refrigerant headers.

The indoor unit equipped with the above-mentioned heat exchanger includes a housing with an intake port and an exhaust port, a fan disposed inside the housing, and at least one heat exchanger disposed above the fan. The heat exchanger disclosed in Patent Document 1 is provided with a water-conducting member that is continuous with at least one of the flat heat transfer tube and the fins, and prevents condensed water generated inside the fins from accumulating.

The heat exchanger disclosed in Patent Document 2 has a blocking wall with an L-shaped cross section at the end of the flat heat transfer tube in the longitudinal direction of the cross section perpendicular to the tube axis of the flat heat transfer tube. The blocking wall covers the lower ends of the fins provided between the flat heat transfer tubes from the outside. Therefore, for example, even if the heat exchanger is placed in a tilted position with the surface on which condensed water collects facing downward, the condensed water will not drip onto the fan and the fan will not splash the water.

JP 2019-027700 A JP 2012-093009 A

The heat exchanger in the indoor unit of an air conditioner functions as an evaporator when in cooling mode to cool the air inside the room. Indoor air is drawn into the indoor unit by the fan, cooled in the heat exchanger, and then blown out into the room. When this happens, if the temperature of the air passing through the heat exchanger falls below the dew point, condensation forms on the surface of the heat exchanger. When this condensation drips from the heat exchanger and is sucked into the fan, it is splashed into the room. For this reason, it is necessary to prevent the condensation from getting caught in the fan.

In Patent Document 1, a water guide member is installed between the heat exchanger and the fan to prevent condensation water from dripping onto the fan. In Patent Document 2, a blocking wall is installed at the end of the flat heat transfer tube on the leeward side to prevent condensation water from dripping onto the fan.

However, the heat exchangers in Patent Documents 1 and 2 have the problem that because structures are added to the heat exchanger to prevent condensation water from dripping onto the fan, the structures increase the pressure loss of the air passing through the heat exchanger, reducing the air flow rate caused by driving the fan and degrading the heat exchanger performance. In addition, there is the problem that the increase in structures that cause condensation water to drip onto the fan increases the number of components of the heat exchanger, increasing costs.

The present disclosure has been made to solve the problems described above, and aims to provide an indoor unit for an air conditioning system that prevents condensation water from dripping onto the fan, while also reducing the cost of the heat exchanger and the decline in heat exchange performance.

The indoor unit of the air conditioner disclosed herein comprises a housing having an intake port and an exhaust port, a fan installed inside the housing, and a heat exchanger arranged above the fan, the heat exchanger comprises a plurality of flat heat transfer tubes arranged in parallel with their tube axes crossing a vertical direction, a plurality of heat transfer fins attached between the plurality of flat heat transfer tubes, and a plurality of refrigerant headers connected to ends of the plurality of flat heat transfer tubes and distributing a refrigerant to the plurality of flat heat transfer tubes or merging refrigerant from the plurality of flat heat transfer tubes, each of the plurality of refrigerant headers being divided into a plurality of header internal spaces by a partition wall, each of the plurality of header internal spaces being connected to at least one of the plurality of flat heat transfer tubes, and a first header internal space located at the top of the plurality of header internal spaces is provided with a connecting pipe and the fan for allowing a refrigerant to flow in or out of the plurality of refrigerant headers. a partition wall disposed in a direction perpendicular to the heat exchanger and connected to the first header internal space, and a second header internal space located at the bottom of the plurality of header internal spaces is connected to the connecting pipe, the first header internal space and the second header internal space are provided in different refrigerant headers among the plurality of refrigerant headers, two refrigerant headers among the plurality of refrigerant headers arranged opposite to each other with the same plurality of flat heat transfer tubes interposed therebetween have the partition wall disposed at the same position in a direction in which the plurality of flat heat transfer tubes are arranged side by side, and a communicating pipe is provided connecting two adjacent header internal spaces among the plurality of header internal spaces, and the communicating pipe connects lower ends of the two header internal spaces to each other, and the refrigerant flowing through the heat exchanger is a single component refrigerant, an azeotropic mixed refrigerant or a quasi-azeotropic mixed refrigerant, and flows into the heat exchanger from the connecting pipe connected to the first header internal space .

The heat exchanger of the indoor unit of the air conditioner disclosed herein has the above-mentioned configuration, which makes it possible to increase the temperature of the refrigerant flowing through the flat heat transfer tubes located vertically above the fan. As a result, the temperature difference between the air passing through and the refrigerant is reduced in the portion of the heat exchanger located above the fan, reducing the amount of condensation water that forms on the surface of the heat exchanger and suppressing the amount of condensation water that drips onto the fan. Furthermore, with the above-mentioned configuration, no structure is added to the portion of the heat exchanger through which the air passes, which makes it possible to suppress increases in costs and increases in air pressure resistance.

1 is a schematic diagram of the internal structure of an indoor unit 100 of an air-conditioning apparatus according to Embodiment 1. FIG. 2 is a cross-sectional view of a heat exchanger 5 of an indoor unit 100 of an air-conditioning apparatus according to Embodiment 1. FIG. 2 is an enlarged view for explaining the positional relationship between a heat exchanger 5 and a fan 4 in FIG. 1. 3 is a schematic diagram of the temperature distribution of the refrigerant flowing through the heat exchanger 5 of the indoor unit 100 of the air-conditioning apparatus according to the first embodiment and the air flowing into the heat exchanger 5. FIG. 10 is a cross-sectional view of a heat exchanger 5 of an indoor unit 100 of an air-conditioning apparatus according to a second embodiment. FIG. 10 is a schematic diagram of the temperature distribution of the non-azeotropic refrigerant flowing through the heat exchanger 5 of the indoor unit 100 of the air-conditioning apparatus according to embodiment 2, and the air flowing into the heat exchanger 5. FIG. 11 is a cross-sectional view of a heat exchanger 5 of an indoor unit 100 of an air-conditioning apparatus according to embodiment 3. FIG. 10 is a cross-sectional view of a heat exchanger 5 of an indoor unit 100 of an air-conditioning apparatus according to embodiment 4. FIG. 9 is a partially enlarged view of the cross-sectional structure of the heat exchanger 5 in the hydrophilic treatment region 15 of FIG. 8 . FIG. 13 is a schematic diagram of the internal structure of an indoor unit 500 of an air-conditioning apparatus according to embodiment 5. 13 is a cross-sectional view of a heat exchanger 505 of an indoor unit 500 of an air-conditioning apparatus according to embodiment 5. FIG.

Below, an embodiment of the indoor unit 100 of the air conditioning apparatus of the present disclosure will be described with reference to the drawings. In the drawings, parts with the same reference numerals are the same or equivalent, and will be common throughout the entire embodiment described below. The forms of the components shown in the entire specification are merely examples, and are not limited to the forms described in the specification. The drawings are schematic, and the size relationships between the components may differ from the actual ones.

Embodiment 1.
1 is a schematic diagram of the internal structure of an indoor unit 100 of an air-conditioning apparatus according to embodiment 1. The indoor unit 100 of the air-conditioning apparatus according to embodiment 1 includes a housing 3 having an air intake 1 and an air outlet 2, a fan 4, a heat exchanger 5, and a drain pan 6.

The fan 4 is disposed within the housing 3 and is driven to rotate to draw indoor air into the housing 3 through the air intake 1. The air taken into the housing 3 passes through the heat exchanger 5 and is then blown out into the room from the air outlet 2. As the air taken into the housing 3 passes through the heat exchanger 5, it exchanges heat with the refrigerant flowing inside the heat exchanger 5, and is cooled or heated. The air cooled or heated in the heat exchanger 5 is blown out into the room from the air outlet 2, thereby conditioning the room.

The fan 4 in embodiment 1 is a cross-flow fan, but is not particularly limited to any type of fan, such as a propeller fan, as long as it has the function of circulating air.

In the first embodiment, the heat exchanger 5 is composed of multiple heat exchangers 5a and 5b, and is located upstream of the air passage with respect to the fan 4, facing each other across the fan 4, and arranged to cover the upper part of the fan 4. The heat exchanger 5 is configured by arranging two heat exchangers 5a and 5b of the same configuration in an inverted V shape on either side of the fan 4 in the cross-sectional structure of the indoor unit 100 of the air conditioning device shown in Figure 1. The two heat exchangers 5a and 5b may be collectively referred to as the heat exchanger 5.

The drain pan 6 is disposed below the heat exchanger 5 and collects condensation water generated on the surface of the heat exchanger 5. In the first embodiment, the drain pan 6 is disposed below the lower end of each of the heat exchangers 5a and 5b, which are disposed at an angle.

(Heat exchanger 5)
Fig. 2 is a cross-sectional view of the heat exchanger 5 of the indoor unit 100 of the air-conditioning apparatus according to embodiment 1. The heat exchanger 5 shows a cross-sectional structure of a portion A-A in Fig. 1. As shown in Fig. 2, the heat exchanger 5 includes a plurality of flat heat transfer tubes 7, a plurality of heat transfer fins 8, and a plurality of refrigerant headers 9.

The flat heat transfer tubes 7 are arranged in parallel with their tube axes oriented in a direction intersecting the vertical direction. In the first embodiment, the flat heat transfer tubes 7 are arranged with their tube axes extending horizontally, and are arranged in parallel at regular intervals. However, the tube axes of the flat heat transfer tubes 7 may be arranged not only horizontally, but also inclined relative to the horizontal direction. Each of the flat heat transfer tubes 7 is made of, for example, aluminum, and has at least one flow path through which the refrigerant flows in a cross section intersecting the tube axis.

Refrigerant headers 9a and 9b are connected to both ends of the flat heat transfer tubes 7. The refrigerant headers 9a and 9b may be collectively referred to as the refrigerant header 9. The refrigerant header 9 receives the refrigerant flowing through the refrigeration cycle circuit and distributes the refrigerant to the flat heat transfer tubes 7. Alternatively, each of the refrigerant headers 9a and 9b has at least one partition wall 10 therein and is partitioned to have multiple header internal spaces 11 therein. In the heat exchanger 5 of FIG. 2, a connection pipe 12 is provided for each of the refrigerant headers 9a and 9b. The refrigerant flowing through the refrigeration cycle circuit flows into the connection pipe 12, or the refrigerant in the refrigerant header 9 flows out to the refrigeration cycle circuit. The refrigerant header 9 is made of, for example, aluminum, but the material is not particularly limited.

The partition wall 10 is disposed inside at least one refrigerant header 9, and the interior of the refrigerant header 9 is divided into a plurality of header internal spaces 11 by the partition wall 10. At least one of the plurality of flat heat transfer tubes 7 is connected to the plurality of header internal spaces 11. For assembly purposes, it is desirable that the material of the partition wall 10 is the same as the material of the refrigerant header 9.

The connection pipe 12 is connected to at least one refrigerant header 9, and allows the refrigerant to flow in and out from the outside of the refrigerant header 9. For assembly purposes, it is desirable that the material of the connection pipe 12 be the same as that of the refrigerant header 9.

The heat transfer fins 8 are arranged between the flat heat transfer tubes 7 in contact with each of the flat heat transfer tubes 7 so as to transfer heat. In the first embodiment, the heat transfer fins 8 are corrugated fins sandwiched between two flat heat transfer tubes 7 arranged adjacent to each other in parallel in the horizontal direction of FIG. 2.

In the heat exchanger 5, air introduced into the housing 3 by the fan 4 shown in FIG. 1 passes through and flows along the surface of the heat transfer fins 8, and heat exchange occurs between the air and the refrigerant flowing inside the flat heat transfer tubes 7. In the first embodiment, the flat heat transfer tubes 7 and the heat transfer fins 8 are connected by brazing, for example, but the form of connection is not particularly limited as long as the flat heat transfer tubes 7 and the heat transfer fins 8 are configured to be able to transfer heat. In the first embodiment, the shape of the heat transfer fins 8 is corrugated, but for example, plate-type fins may be arranged.

3 is an enlarged view illustrating the positional relationship between the heat exchanger 5 and the fan 4 in FIG. 1. The heat exchanger 5 according to the first embodiment is inclined with respect to the vertical direction toward the upstream side of the fan 4, and its upper end 5A is located vertically above the fan 4. When the flat heat transfer tube 7 closest to the vertical plane 201 passing through the rotation axis of the fan 4 is the flat heat transfer tube 7A, and the flat heat transfer tubes 7 arranged in order downward from there in the direction of gravity are the flat heat transfer tubes 7B, 7C, 7D, 7E, etc., the flat heat transfer tubes 7A, 7B, and 7C are located above the fan 4. As shown in FIG. 2, the flat heat transfer tubes 7A, 7B, and 7C located above the fan 4 are connected to the header internal space 11a among the multiple header internal spaces 11a and 11c of the refrigerant header 9a. The header internal space 11a of the refrigerant header 9a may be referred to as the first header internal space.

The header internal space 11a has a smaller volume than the header internal space 11c and is located at the top of the header internal space 11c. In addition, the header internal space 11a may be connected not only to the flat heat transfer tubes 7A, 7B, and 7C, but also to the flat heat transfer tube 7D that is located above the fan 4.

The flat heat transfer tubes 7, one end of which is connected to the header internal space 11a, are connected to the refrigerant header 9b at the other end. In the first embodiment, the refrigerant header 9b is partitioned by a partition wall 10 and has a plurality of header internal spaces 11b and 11d above and below. The header internal space 11b of the refrigerant header 9b has a larger volume than the header internal space 11d located below.

The header internal space 11a of one refrigerant header 9a is connected to the header internal space 11b of the other refrigerant header 9b by a plurality of flat heat transfer tubes 7A, 7B, 7C and 7D.

The header internal space 11b of the other refrigerant header 9b is connected to a plurality of flat heat transfer tubes 7A, 7B, 7C and 7D connected to the header internal space 11a of the other refrigerant header 9a, as well as a plurality of flat heat transfer tubes 7E, 7F, 7G and 7H.

The flat heat transfer tubes 7E, 7F, 7G, and 7H are connected to the header internal space 11b of one refrigerant header 9a. The header internal space 11c located below one refrigerant header 9a is connected to the flat heat transfer tubes 7E, 7F, 7G, and 7H connected to the header internal space 11b of the other refrigerant header 9b, as well as to the flat heat transfer tubes 7I, 7J, and 7K.

The flat heat transfer tubes 7I, 7J, and 7K are connected to a header internal space 11d located below the other refrigerant header 9b. The header internal space 11d of the other refrigerant header 9b has a smaller volume than the header internal space 11b located above, and is connected to a connection pipe 12. The header internal space 11d of the refrigerant header 9b may be referred to as the second header internal space.

As described above, in the heat exchanger 5 according to the first embodiment, the refrigerant flowing in from the connecting pipe 12 of one refrigerant header 9a travels between the refrigerant headers 9 via the flat heat transfer tubes 7, and finally flows out from the connecting pipe 12 of the other refrigerant header 9b. The header internal space 11 of the heat exchanger 5 has the function of collecting or distributing the refrigerant passing through the flat heat transfer tubes 7 therebetween, and also provides a separation action in the direction of gravity due to differences in refrigerant density and specific gravity.

In the first embodiment, when the air conditioner is in cooling operation, i.e., when the heat exchanger 5 of the indoor unit 100 of the air conditioner functions as an evaporator, the refrigerant flowing through the heat exchanger 5 flows in the directions of the arrows 101 and 102 shown in Fig. 2. In other words, the connection pipe 12 connected to the header internal space 11a at the top of the refrigerant header 9a of the heat exchanger 5 serves as the refrigerant inlet, and the connection pipe 12 connected to the header internal space 11d at the bottom of the other refrigerant header 9b serves as the refrigerant outlet.

When the air conditioner is in cooling operation, a two-phase gas-liquid refrigerant flows into the header internal space 11a of the heat exchanger 5. As the two-phase gas-liquid refrigerant moves from the header internal space 11a to the header internal spaces 11b, 11c, and 11d, heat exchange with the air progresses inside the flat heat transfer tubes 7, and the proportion of gas-phase refrigerant increases. Then, by the time it reaches the header internal space 11d of the refrigerant header 9b, it becomes a single-phase gas refrigerant.

Figure 4 is a schematic diagram of the temperature distribution of the refrigerant flowing through the heat exchanger 5 of the indoor unit 100 of the air conditioning apparatus according to embodiment 1 and the air flowing into the heat exchanger 5. In embodiment 1, the type of refrigerant flowing through the refrigeration cycle circuit is, for example, R32 or R410A, and is a single component refrigerant, an azeotropic mixed refrigerant, or a pseudo-azeotropic mixed refrigerant. When the refrigerant is a single component refrigerant, an azeotropic mixed refrigerant, or a pseudo-azeotropic mixed refrigerant as in embodiment 1, the refrigerant temperature in the gas-liquid two-phase state is equal to its boiling point.

However, the pressure of the refrigerant flowing inside the heat exchanger 5 is high at the inlet side and low at the outlet side due to wall friction loss and losses caused by the flow path shape as the flow path expands and contracts. Therefore, the temperature of the region in the heat exchanger 5 where the refrigerant is in a two-phase gas-liquid state is high upstream of the flow where the pressure is increasing, and decreases downstream.

The refrigerant flowing inside the heat exchanger 5 exchanges heat with the indoor air taken in by the fan 4 through a plurality of flat heat transfer tubes 7 and heat transfer fins 8. As shown in FIG. 4, the temperature of the indoor air taken in from the room is almost constant. The smaller the difference between the temperature of the refrigerant flowing inside the heat exchanger 5 and the temperature of the indoor air, the smaller the heat exchange amount in the heat exchanger 5. When the heat exchange amount is small, the temperature of the air flowing out from the heat exchanger 5 becomes high. In other words, the temperature of the air passing through the refrigerant inlet side of the heat exchanger 5, i.e., the upstream, and exiting is relatively high, and the temperature of the air passing through the refrigerant outlet side of the heat exchanger 5, i.e., the downstream, and exiting is relatively low. In the left region of FIG. 4, the temperature of the air passing through the heat exchanger 5 and exiting is relatively high. Also, in the right region of FIG. 4, the temperature of the air passing through the heat exchanger 5 and exiting is lower than the left region.

Because the temperature of the refrigerant on the outlet side of the heat exchanger 5 becomes low, when this temperature falls below the dew point temperature of the indoor air passing through the heat exchanger 5, condensation water forms on the surface of the heat exchanger 5. At this time, the greater the difference between the refrigerant temperature of the heat exchanger 5 and the temperature of the indoor air passing through the heat exchanger 5, i.e., the greater the amount of heat exchange between the refrigerant and the indoor air, the greater the amount of condensation water that forms.

In the heat exchanger 5 of the indoor unit 100 of the air conditioner according to the first embodiment, as shown in Figs. 2 to 4, the temperature of the refrigerant is high on the upstream side of the refrigerant flowing through the heat exchanger 5. That is, the flat heat transfer tubes 7A, 7B, and 7C located above the fan 4 shown in Fig. 3 have a high temperature. Therefore, the amount of condensation water generated at the upper end 5A of the heat exchanger 5 located vertically above the fan 4 is reduced. As a result, it is possible to reduce the amount of condensation water generated at the upper end 5A of the heat exchanger 5 located vertically above the fan 4 dripping toward the fan 4, and the indoor unit 100 of the air conditioner reduces the phenomenon in which condensation water is scattered indoors, that is, the so-called dew splashing. In addition, since no structure is added to the part of the heat exchanger through which the air passes, it is possible to suppress an increase in costs and an increase in air pressure resistance.

Embodiment 2.
An indoor unit 100 of an air-conditioning apparatus according to embodiment 2 will be described. The indoor unit 100 of an air-conditioning apparatus according to embodiment 2 is different from embodiment 1 in that the flow direction of the refrigerant flowing through the heat exchanger 5 and the refrigerant are changed. In embodiment 2, the differences from embodiment 1 will be mainly described.

Figure 5 is a cross-sectional view of the heat exchanger 5 of the indoor unit 100 of the air conditioning apparatus according to embodiment 2. Figure 5 shows the cross-sectional structure of part A-A in Figure 1. In embodiment 2, the type of refrigerant is a non-azeotropic mixed refrigerant.

In the second embodiment, when the indoor unit 100 of the air conditioner is in cooling operation, i.e., when the heat exchanger 5 functions as an evaporator, the refrigerant flows in the direction of the arrow 101 shown in FIG. 5. In other words, the connection pipe 12 connected to the lower part of the refrigerant header 9b of the heat exchanger 5 is the refrigerant inlet, and the connection pipe 12 connected to the upper part of the other refrigerant header 9a is the refrigerant outlet. Therefore, in the heat exchanger 5 according to the second embodiment, the refrigerant flows in the order of the header internal spaces 11d, 11c, 11b, and 11a, and the refrigerant flows out from the connection pipe 12 connected to the header internal space 11a.

When the heat exchanger 5 functions as an evaporator, the refrigerant flowing inside is in a two-phase gas-liquid state, where liquid and gas are mixed, and as it approaches the refrigerant outlet, the proportion of liquid refrigerant in the two-phase gas-liquid state decreases due to the progress of heat exchange between the air and the refrigerant. Then, at the refrigerant outlet of the heat exchanger 5, all of the liquid refrigerant evaporates and becomes a single-phase gas flow.

In the second embodiment, a non-azeotropic refrigerant such as R404A is used as the refrigerant. A non-azeotropic refrigerant is a mixture of refrigerants having different boiling points. When evaporation occurs in a non-azeotropic refrigerant, the refrigerant with the lower boiling point evaporates first, followed by the refrigerant with the higher boiling point. For this reason, when the refrigerant flowing through the heat exchanger 5 is a non-azeotropic refrigerant, the refrigerant temperature increases as evaporation progresses, i.e., the further downstream the refrigerant flows in the heat exchanger 5.

The refrigerant flowing inside the heat exchanger 5 exchanges heat with the indoor air taken in by the fan 4 via the flat heat transfer tubes 7 and heat transfer fins 8. The temperature of the indoor air taken in from the room is constant in each part of the heat exchanger 5. The smaller the temperature difference between the temperature of the refrigerant flowing inside the heat exchanger 5 and the temperature of the indoor air, the smaller the amount of heat exchange, i.e., the higher the air temperature when it leaves the heat exchanger 5.

If the temperature of the indoor air passing through the heat exchanger 5 falls below the dew point temperature, condensation water will form on the surface of the heat exchanger 5. Therefore, the greater the difference between the refrigerant temperature of the heat exchanger 5 and the temperature of the indoor air flowing into the heat exchanger 5, i.e., the greater the amount of heat exchange, the greater the amount of condensation water that will be generated.

Figure 6 is a schematic diagram of the temperature distribution of the non-azeotropic refrigerant flowing through the heat exchanger 5 of the indoor unit 100 of the air conditioner according to embodiment 2 and the air flowing into the heat exchanger 5. In the indoor unit 100 of the air conditioner according to embodiment 2, as shown in Figures 5 and 6, the temperature of the refrigerant flowing through the flat heat transfer tube 7 located downstream of the refrigerant flowing through the heat exchanger 5, i.e., at the top of the heat exchanger 5, is high. Therefore, the temperature of the upper end 5A of the heat exchanger 5 located above the fan 4 is higher than the temperature of the lower part of the heat exchanger 5. Therefore, the amount of condensation water generated at the upper end 5A of the heat exchanger 5 located above the fan 4 can be reduced. As a result, the amount of condensation water dripping from the upper end 5A of the heat exchanger 5 located vertically above the fan 4 toward the fan 4 can be reduced, and the indoor unit 100 of the air conditioner can reduce the phenomenon in which condensation water scatters indoors, so-called dew splashing.

According to the indoor unit 100 of the air conditioner of the second embodiment, the refrigerant is a non-azeotropic refrigerant, and as shown in Fig. 5, the refrigerant flows in from the connection pipe 12 connected to the header internal space 11d, which is the second header internal space of the heat exchanger 5. The refrigerant then travels between the refrigerant headers 9a and 9b, which are arranged opposite each other, via a plurality of flat heat transfer tubes 7, and flows out from the connection pipe 12 connected to the header internal space 11a, which is the first header internal space.

As a result of the above configuration, the heat exchanger 5 is less likely to produce condensation water because the temperature of the refrigerant flowing through the flat heat transfer tubes 7A-7D connected to the header internal space 11a, which is the first header internal space, is relatively high. In other words, the amount of condensation water that forms at the upper end 5A of the heat exchanger 5 located vertically above the fan 4 is reduced, preventing condensation water from dripping onto the fan 4, and reducing so-called dew splashing.

Embodiment 3.
An explanation will be given of an indoor unit 100 of an air conditioner according to embodiment 3. The indoor unit 100 of an air conditioner according to embodiment 3 is obtained by modifying the structure of the refrigerant header of the heat exchanger 5 from embodiment 1. The explanation of embodiment 3 will be centered on the differences from embodiment 1.

Figure 7 is a cross-sectional view of the heat exchanger 5 of the indoor unit 100 of the air conditioner according to the third embodiment. Figure 7 shows the cross-sectional structure of the A-A part in Figure 1. In the heat exchanger 5 according to the third embodiment, the partition walls 10 provided inside the refrigerant headers 9a and 9b are provided at the same height in the vertical direction, that is, in the parallel direction of the flat heat transfer tubes 7. In other words, among the multiple header internal spaces 11 provided in each of the refrigerant headers 9a and 9b arranged opposite each other with the flat heat transfer tubes 7 in between, the two header internal spaces 11 arranged opposite each other are connected one-to-one by the flat heat transfer tubes 7. In other words, the header internal space 11e located at the top of the refrigerant header 9a and the header internal space 11f located at the top of the refrigerant header 9b facing it are connected to each other by the flat heat transfer tubes 7A to 7D, and are not connected to other header internal spaces 11 by the flat heat transfer tubes 7.

The refrigerant header 9a has header internal spaces 11e, 11h, and 11i inside. The header internal space 11e, which is located at the top, is connected to a connection pipe 12, through which refrigerant flows in from the outside. The header internal spaces 11h and 11i are located below the header internal space 11e, and the header internal spaces 11h and 11i are connected by a communication pipe 14.

The refrigerant header 9b has header internal spaces 11f, 11g, and 11j inside. The uppermost header internal space 11f and the adjacent header internal space 11g located below are connected by a communication pipe 14. The header internal space 11j is located below the header internal space 11g and adjacent thereto, and a connection pipe 12 is connected thereto.

In the refrigerant headers 9a and 9b arranged opposite each other at both ends of the flat heat transfer tubes 7, the header internal spaces 11 arranged at the same position in the height direction are connected by the same flat heat transfer tubes 7. In other words, the header internal spaces 11e and 11f are connected by the flat heat transfer tubes 7A to 7D. The header internal spaces 11h and 11g are connected by the flat heat transfer tubes 7E to 7H. The header internal spaces 11i and 11j are connected by the flat heat transfer tubes 7I to 7K.

In the heat exchanger 5 according to the third embodiment, the header internal spaces 11 adjacent to each other in the same refrigerant header 9 are connected by a communication pipe 14. At this time, the opening of the communication pipe 14 is located at the same position as or below the flat heat transfer tube 7 that is located at the lowest end in the direction of gravity among the flat heat transfer tubes 7 connected to the header internal space 11. For example, in the header internal space 11f, the communication pipe 14 is connected at the same height or lower position as the flat heat transfer tube 7D in the direction of gravity. In the header internal space 11g, the communication pipe 14 is connected at the same height or lower position as the flat heat transfer tube 7H in the direction of gravity. The communication pipes 14 connected to the header internal space 11h and the header internal space 11i are also configured in the same manner as the header internal spaces 11f and 11g.

In addition, in the third embodiment, the connection pipe 12 is connected so as to open at the same position as or below the lowermost flat heat transfer tube 7 connected to the header internal space 11 to which the connection pipe 12 is connected. For example, in the header internal space 11e, the connection pipe 12 is connected at the same height or lower position as the flat heat transfer tube 7D in the direction of gravity. In the header internal space 11d, the connection pipe 12 is connected at the same height or lower position as the flat heat transfer tube 7K in the direction of gravity.

In addition, for assembly purposes, it is desirable that the material of the connecting pipe 12 and the communicating pipe 14 be the same as that of the refrigerant header 9.

In the indoor unit 100 of the air-conditioning apparatus according to the third embodiment, the refrigerant flowing through the heat exchanger 5 flows in the direction shown by the arrows 101 and 102 in Fig. 7. That is, the refrigerant that flows into the header internal space 11e passes through the flattened heat transfer tubes 7 and the communicating pipes 14, flows through the header internal spaces 11f, 11g, 11h, 11i, and 11j in that order, and flows out from the connecting pipe 12 connected to the header internal space 11j. In the third embodiment, the header internal space 11e corresponds to the first header internal space, and the header internal space 11j corresponds to the second header internal space.

In each header internal space 11, the flow of the refrigerant distributed to the flat heat transfer tubes 7 flows in the opposite direction to the direction of gravity. For example, in the header internal space 11e to which the connection pipe 12 is connected, the refrigerant 101 flowing from the connection pipe 12 flows upward inside the header internal space 11e and flows into each of the flat heat transfer tubes 7. When the air conditioning device is in cooling operation, the refrigerant 101 flowing into the heat exchanger 5 is a gas-liquid two-phase refrigerant. Among the gas-liquid two-phase refrigerants, the liquid refrigerant has a higher specific gravity than the gas-phase refrigerant, so it is easily transported to the top of the header internal space 11e due to the inertial force when it flows into the header internal space 11e. This makes it easier for the liquid refrigerant to be distributed to each of the flat heat transfer tubes 7 in the header internal space 11e. In addition, since the liquid refrigerant is distributed to each of the multiple flat heat transfer tubes 7, the temperature variation of each of the multiple flat heat transfer tubes 7 connected to the header internal space 11e is reduced, making it possible to prevent a decrease in the heat exchange performance of the heat exchanger 5.

In the header internal space 11g and the header internal space 11i to which the communication pipe 14 is connected, the liquid refrigerant is distributed to each of the flat heat transfer tubes 7 by inertial force, similar to the header internal space 11e described above. Therefore, the temperature variation of each of the flat heat transfer tubes 7 connected to the header internal space 11g and the header internal space 11h is reduced.

In the header internal space 11f and the header internal space 11h to which the communicating pipe 14 is connected, the refrigerant flowing in from the flat heat transfer tubes 7 moves downward due to gravity and flows into the communicating pipe 14 with inertial force. The refrigerant then flows into the next header internal space 11g or 11i with inertial force through the communicating pipe 14. In other words, by connecting the lower ends of adjacent header internal spaces 11 of the refrigerant header 9 with the communicating pipe 14, the variation in the distribution of the refrigerant to the flat heat transfer tubes 7 in each header internal space 11 can be reduced.

In the heat exchanger 5 shown in FIG. 7, the communication pipe 14 is arranged outside the refrigerant header 9, but it may be arranged, for example, inside the refrigerant header 9. The position where the communication pipe 14 is arranged is not particularly limited as long as the position where it opens in the header internal space 11 is the same.

In FIG. 7, the refrigerant is shown to flow from the header internal space 11e to the header internal space 11j, but this shows the flow when the refrigerant is a single component refrigerant, an azeotropic mixed refrigerant, or a pseudo-azeotropic mixed refrigerant. In other words, when the refrigerant is a single component refrigerant, an azeotropic mixed refrigerant, or a pseudo-azeotropic mixed refrigerant, the indoor unit 100 of the air conditioning device is configured so that the refrigerant flows into the first header internal space. When a non-azeotropic mixed refrigerant is used as the refrigerant, the refrigerant flows from the header internal space 11j to the header internal space 11e. In other words, when the refrigerant is a non-azeotropic mixed refrigerant, the indoor unit 100 of the air conditioning device is configured so that the refrigerant flows into the second header internal space.

The installation position of the partition wall 10 of the refrigerant header 9 may be changed as appropriate. The area of the refrigerant flow path of the header internal space 11 can be determined by the installation position of the partition wall 10, so that the flow path area can be set as appropriate, for example, according to the phase change of the refrigerant from the inlet to the outlet of the heat exchanger 5. Specifically, since the refrigerant is mostly liquid on the inlet side of the heat exchanger 5 and gaseous on the outlet side, the position of the partition wall 10 may be changed so that the volume of the header internal space 11 increases in the refrigerant flow path area from the inlet to the outlet.

Embodiment 4.
An explanation will be given of an indoor unit 100 of an air conditioner according to embodiment 4. The indoor unit 100 of an air conditioner according to embodiment 4 is obtained by changing the surface treatment of the flat heat transfer tubes 7 and the heat transfer fins 8 of the heat exchanger 5 from embodiment 1. In embodiment 4, the differences from embodiment 1 will be mainly explained.

Figure 8 is a cross-sectional view of the heat exchanger 5 of the indoor unit 100 of the air conditioner according to embodiment 4. The heat exchanger 5 according to embodiment 4 has the same structure as the heat exchanger 5 according to embodiment 1. However, in embodiment 4, the heat transfer fins 8 connected to the flat heat transfer tubes 7 in the hydrophilic treatment area 15 have their surfaces hydrophilically treated. The hydrophilic treatment area 15 is an area including a plurality of flat heat transfer tubes 7A to 7D connected to the header internal space 11a to which the flat heat transfer tube 7A closest to the vertical plane 201 passing through the rotation axis of the fan 4 shown in Figure 3 is connected, and the heat transfer fins 8 joined to them. The hydrophilic treatment area 15 includes at least the upper end 5A of the heat exchanger 5 located above the fan 4.

Figure 9 is a partially enlarged view of the cross-sectional structure of the heat exchanger 5 in the hydrophilic treatment area 15 of Figure 8. In the indoor unit 100 of the air conditioning device according to embodiment 4, the contact angle of the condensation water generated on the surface of the heat exchanger 5 is reduced by the hydrophilic treatment. Therefore, the condensation water does not bridge within the bent structure of the heat transfer fins 8, which are particularly configured in a corrugated shape, but travels along the flat heat transfer tubes 7 and the heat transfer fins 8 and is discharged by gravity to the bottom of the heat exchanger 5 and drips into the drain pan 6. This makes it possible to suppress the condensation water from dripping from the upper end 5A of the heat exchanger 5 located vertically above the fan 4 onto the fan 4.

In addition, the hydrophilic treatment area 15 may be a hydrophilic treatment applied not only to the heat transfer fins 8 but also to the flat heat transfer tubes 7. That is, in the hydrophilic treatment area 15, at least one of the heat transfer fins 8 and the flat heat transfer tubes 7 is hydrophilically treated. Even if only the flat heat transfer tubes 7 are hydrophilically treated, condensed water is less likely to be retained around the joint between the heat transfer fins 8 and the flat heat transfer tubes 7, and the condensed water is more likely to be discharged to the lower part of the heat exchanger 5 by gravity. This makes it possible to suppress condensed water from dripping from the upper end 5A of the heat exchanger 5 located vertically above the fan 4 onto the fan 4.

Embodiment 5.
An indoor unit 500 of an air-conditioning apparatus according to embodiment 5 will be described. The indoor unit 500 of an air-conditioning apparatus according to embodiment 5 is modified from embodiment 1 in terms of the structure of the heat exchanger 5 and the arrangement within the housing 3. In embodiment 5, the differences from embodiment 1 will be mainly described.

Figure 10 is a schematic diagram of the internal structure of an indoor unit 500 of an air conditioning apparatus according to embodiment 5. In embodiment 5, a heat exchanger 505 consisting of two heat exchangers 505a and 505b of different sizes is arranged inside the housing 3. One of the heat exchangers 505a and 505b, heat exchanger 505b, is located above the fan 4.

Figure 11 is a cross-sectional view of a heat exchanger 505 of an indoor unit 500 of an air conditioning apparatus according to embodiment 5. Figure 11 shows the cross-sectional structure of the heat exchanger 5 at parts B-B and C-C in Figure 10. In embodiment 5, a heat exchanger connection pipe 512 is installed so that the refrigerant flowing inside the heat exchanger 5 flows through the smaller heat exchanger 505a and then to the larger heat exchanger 505b, as shown by arrow 101 in Figure 11.

In the air conditioning device according to the fifth embodiment, a single component refrigerant, an azeotropic mixed refrigerant, or a pseudo-azeotropic mixed refrigerant is used as the refrigerant. As shown in FIG. 11, the heat exchanger 505 is configured so that the refrigerant flows from the heat exchanger 505a located above the fan 4 to the heat exchanger 505b. That is, the refrigerant flows into the heat exchanger 505 from the header internal space 11k, which is the first header internal space. The refrigerant that flows into the header internal space 11k passes through a plurality of flat heat transfer tubes 7A to 7D and flows into the header internal space 11m. The refrigerant flows from the header internal space 11m through the header internal space 11n and the heat exchanger connection pipe 512 into the refrigerant header 9c of the heat exchanger 505b. The refrigerant that flows into the heat exchanger 505b flows in the order of the header internal spaces 11p, 11q, 11r, and 11s, and flows out of the connection pipe 12 connected to the header internal space 11s of the refrigerant header 9d. In this case, as described with reference to FIG. 4, the upstream region of the heat exchanger 505a, that is, the upper end portion 505A of the heat exchanger 505a, is a region where the temperature is relatively high, and therefore the generation of condensation water is reduced.

In the air conditioning device according to the fifth embodiment, the refrigerant may be a non-azeotropic mixed refrigerant. In this case, as explained in FIG. 6, the refrigerant temperature downstream of the heat exchanger 505 becomes high. Therefore, when the refrigerant is a non-azeotropic mixed refrigerant in the air conditioning device according to the fifth embodiment, the refrigerant is made to flow in the opposite direction to the arrow 101 shown in FIG. 11. That is, the refrigerant flows into the heat exchanger 505 from the header internal space 11s, which is the second header internal space. By being configured in this manner, the indoor unit 500 of the air conditioning device according to the fifth embodiment can reduce the generation of condensation water in the heat exchanger 505 and suppress the dripping of condensation water onto the fan 4.

As described above, embodiments 1 to 5 of the present disclosure have been described. However, embodiments 1 to 5 are merely examples of the indoor units 100 and 500 of the air conditioning system, and they can be combined with other known technologies, and the embodiments can also be combined. Note that the indoor units 100 and 500 of the air conditioning system can also have parts of their configuration omitted or modified without departing from the gist of the present disclosure.

1 air intake, 2 air outlet, 3 housing, 4 fan, 5 heat exchanger, 5A upper end, 5a heat exchanger, 6 drain pan, 7 flat heat transfer tube, 7A flat heat transfer tube, 7B flat heat transfer tube, 7C flat heat transfer tube, 7D flat heat transfer tube, 7E flat heat transfer tube, 7F flat heat transfer tube, 7G flat heat transfer tube, 7H flat heat transfer tube, 7I flat heat transfer tube, 7J flat heat transfer tube, 7K flat heat transfer tube, 8 heat transfer fin, 9 refrigerant header, 9a refrigerant header, 9b refrigerant header, 9c refrigerant header, 9d refrigerant header, 10 partition wall, 11 header internal space, 11a header internal space, 11b header internal space, 11c header internal space, 11d header internal space, 11e header internal space, 11f Header internal space, 11g header internal space, 11h header internal space, 11i header internal space, 11j header internal space, 11k header internal space, 11m header internal space, 11n header internal space, 11p header internal space, 11q header internal space, 11r header internal space, 11s header internal space, 12 connecting pipe, 14 communicating pipe, 15 hydrophilic treatment area, 100 indoor unit, 101 refrigerant, 201 vertical plane, 500 indoor unit, 505 heat exchanger, 505a heat exchanger, 505b heat exchanger, 512 heat exchanger connecting pipe.

Claims (7)

A housing having an intake port and an exhaust port;
A fan installed inside the housing;
a heat exchanger disposed above the fan;
The heat exchanger includes:
A plurality of flat heat transfer tubes arranged in parallel with their tube axes crossing a vertical direction;
A plurality of heat transfer fins are attached between the plurality of flat heat transfer tubes;
a plurality of refrigerant headers connected to ends of the plurality of flat heat transfer tubes and distributing the refrigerant to the plurality of flat heat transfer tubes or merging the refrigerant from the plurality of flat heat transfer tubes;
Each of the plurality of refrigerant headers includes:
The interior is divided into multiple header internal spaces by partition walls,
Each of the plurality of header internal spaces includes:
At least one of the plurality of flat heat transfer tubes is connected,
The first header internal space located at the top of the plurality of header internal spaces is
A connection pipe for allowing a refrigerant to flow in or out of the refrigerant headers and the flat heat transfer tubes located vertically above the fan are connected to the refrigerant headers,
The second header internal space located at the bottom of the plurality of header internal spaces is
The connection pipe is connected,
The first header internal space and the second header internal space are:
The refrigerant headers are provided in different ones of the plurality of refrigerant headers,
Among the plurality of refrigerant headers, two refrigerant headers arranged opposite each other with the same plurality of flat heat transfer tubes interposed therebetween are
The partition walls are arranged at the same positions in a direction in which the flat heat transfer tubes are arranged side by side,
a communication pipe connecting two adjacent header internal spaces among the plurality of header internal spaces,
The communication pipe is
Connecting lower ends of the two header internal spaces to each other,
The refrigerant flowing through the heat exchanger is
A single component refrigerant, an azeotropic mixed refrigerant, or a near-azeotropic mixed refrigerant,
an indoor unit of an air conditioner, wherein air flows into the heat exchanger from the connection pipe connected to the first header internal space; The first header internal space is
The indoor unit of an air conditioner according to claim 1 , wherein the header internal space has a smaller volume than any of the other header internal spaces. A housing having an intake port and an exhaust port;
A fan installed inside the housing;
a heat exchanger disposed above the fan;
The heat exchanger includes:
A plurality of flat heat transfer tubes arranged in parallel with their tube axes crossing a vertical direction;
A plurality of heat transfer fins are attached between the plurality of flat heat transfer tubes;
a plurality of refrigerant headers connected to ends of the plurality of flat heat transfer tubes and distributing the refrigerant to the plurality of flat heat transfer tubes or merging the refrigerant from the plurality of flat heat transfer tubes;
Each of the plurality of refrigerant headers includes:
The interior is divided into multiple header internal spaces by partition walls,
Each of the plurality of header internal spaces includes:
At least one of the plurality of flat heat transfer tubes is connected,
The first header internal space located at the top of the plurality of header internal spaces is
A connection pipe for allowing a refrigerant to flow in or out of the refrigerant headers and the flat heat transfer tubes located vertically above the fan are connected to the refrigerant headers,
The second header internal space located at the bottom of the plurality of header internal spaces is
The connection pipe is connected,
The first header internal space and the second header internal space are:
The refrigerant headers are provided in different ones of the plurality of refrigerant headers,
Among the plurality of refrigerant headers, two refrigerant headers arranged opposite each other with the same plurality of flat heat transfer tubes interposed therebetween are
The partition walls are arranged at the same positions in a direction in which the flat heat transfer tubes are arranged side by side,
a communication pipe connecting two adjacent header internal spaces among the plurality of header internal spaces,
The communication pipe is
Connecting lower ends of the two header internal spaces to each other,
The refrigerant flowing through the heat exchanger is
It is a non-azeotropic refrigerant mixture,
an indoor unit of an air conditioner, wherein air flows into the heat exchanger from the connection pipe connected to the second header internal space; The connecting pipe is
An indoor unit of an air conditioning apparatus described in any one of claims 1 to 3, which is connected at the same height or below the lowest flat heat transfer tube among the plurality of flat heat transfer tubes connected to the first header internal space or the second header internal space. The heat exchanger includes:
the plurality of heat exchangers;
Among the plurality of heat exchangers, the heat exchanger located vertically above the fan is
The indoor unit of the air conditioner according to any one of claims 1 to 4, comprising the refrigerant header in which the first header internal space is provided. The indoor unit of the air conditioner according to claim 5, further comprising a heat exchanger connection pipe that connects the refrigerant headers of the plurality of heat exchangers. Among the plurality of flat heat transfer tubes or the plurality of heat transfer fins connected to the first header internal space, the heat transfer fins installed on the plurality of flat heat transfer tubes are
The indoor unit for an air conditioner according to any one of claims 1 to 6, wherein a surface of the indoor unit is subjected to a hydrophilic treatment.

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