Patent Application
20220120451
The present invention relates to an air conditioner.
Conventionally, for air conditioners, heat exchangers using flat tubes have been known. In order to improve the heat transfer coefficient, some of these heat exchangers are provided with bulging portions, each of which protrudes intersecting with the flow direction of an air flow, on the places of the fins between the upper and lower flat tubes (intermediate regions). However, there is a case where a phenomenon (deflected flows) occurs such that the flow velocity of air flows passing through the bulging portions and through the gaps between the bulging portions and the flat tubes becomes greatly different. In this case, the heat exchange comes to be improperly performed, and makes it difficult to achieve the performance improvement expected to the heat exchanger.
On the other hand, in order to suppress the deflected flows on the surface of the fins, some technology has been disclosed (for example, see Patent Literature 1) in which, other than first bulging portions provided in the intermediate regions, a second bulging portion is provided on a connection region of the fins that connects the intermediate regions to each other, to overlap with the gaps generated between the first bulging portions and the flat tubes when viewed in the ventilation directions. According to this technology, the air flows passing through the heat exchanger are less likely to generate deflected flows in which the flow velocity in passing through the gaps is significantly larger than the flow velocity in passing around the protruding portions. As a result, the heat exchange comes to be properly performed between the air flows and the refrigerant in the flat tubes, and makes it possible to achieve the performance improvement expected by providing the bulging portions.
However, the technology of Patent Literature 1 can suppress the deflected flows on the surface of the fins, but has a problem in that the structure according to this technology is not designed to suppress so-called dew splash in which the condensed water accumulated around the flat tubes is scattered.
Patent Literature 1: Japanese Laid-open Patent Publication No. 2017-194264
The present invention has been made to solve the problems described above, and has an object to suppress the dew splash of condensed water accumulated on the surface of the fins or flat tubes.
(1). According to an aspect of an embodiment, an air conditioner includes a heat exchanger that is arranged in a ventilation flue inside a housing, and a blower that is arranged in the ventilation flue, wherein the heat exchanger includes a plurality of flat tubes, and a fin that includes a plurality of notch portions arranged side by side in a vertical direction, to which the plurality of flat tubes are inserted, and includes intermediate regions each formed between two of the notch portions adjacent to each other in a vertical direction, and a connection region connecting the intermediate regions to each other, the heat exchanger is arranged in a state where the intermediate regions are present on a windward side in a ventilation direction of air flowing in the ventilation flue, with respect to the connection region, the heat exchanger includes first bulging portions that are at least partly positioned on the intermediate regions, and a second bulging portion that overlaps with a gap generated between the first bulging portions and the flat tubes when the heat exchanger is viewed from the windward side in a direction of a drag line, and the drag line is defined by a virtual line that extends from a start point at a point where condensed water is accumulated on the fin, on the windward side, to an end point at a point where a static pressure in the ventilation flue is lowest, on a leeward side.
(2). The air conditioner according to (1), wherein the blower is provided on a downstream side in the ventilation direction from the heat exchanger in the ventilation flue, and the end point is at a center of the blower.
(3). The air conditioner according to (1), wherein
the blower is provided on an upstream side in the ventilation direction from the heat exchanger in the ventilation flue, and
the end point is at a center of a position where a flow passage cross-sectional area is minimum in the ventilation flue.
(4). The air conditioner according to (1), wherein each of the first bulging portions is formed with an upper end edge positioned to fall within a range of 4 mm or less from a lower side of a first notch portion on an upper side.
(5). The air conditioner according to (1), wherein the first bulging portions and the second bulging portion are formed such that a distance between the notch portions and the second bulging portion is equal to or larger than a distance between the first bulging portions and the second bulging portion.
According to the present invention, it is possible to suppress the dew splash of condensed water accumulated on the surface of the fins or flat tubes.
An embodiment of the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiment, but may be modified in various ways without departing from the gist of the present invention.
<Configuration of Refrigerant Circuit>
First, with reference to
<<Refrigerant Circuit of Outdoor Unit>>
First, the outdoor unit 2 will be explained. The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an expansion valve 24, the liquid side closing valve 25 to which the liquid pipe 4 is connected, the gas side closing valve 26 to which the gas pipe 5 is connected, and an outdoor fan 27. Further, these respective devices except the outdoor fan 27 are connected to each other by respective refrigerant pipes described later to form an outdoor unit refrigerant circuit 10a that serves as one section of the refrigerant circuit 10. Here, an accumulator (not illustrated) may be provided on the refrigerant suction side of the compressor 21.
The compressor 21 is a variable capacity type compressor that can change the operation capacity by controlling the number of revolutions with an inverter (not illustrated). The refrigerant discharge side of the compressor 21 is connected to the port “a” of the four-way valve 22 by a discharge pipe 61. Further, the refrigerant suction side of the compressor 21 is connected to the port “c” of the four-way valve 22 by a suction pipe 66.
The four-way valve 22 is a valve for switching the flow direction of the refrigerant, and includes four ports of “a, b, c, and d”. The port “a” is connected to the refrigerant discharge side of the compressor 21 by the discharge pipe 61, as described above. The port “b” is connected to one of the refrigerant gateways of the outdoor heat exchanger 23 by a refrigerant pipe 62. The port “c” is connected to the refrigerant suction side of the compressor 21 by the suction pipe 66, as described above. Further, the port “d” is connected to the gas side closing valve 26 by an outdoor unit gas pipe 64. Here, the four-way valve 22 is a flow passage switching means according to the present invention.
The outdoor heat exchanger 23 serves to perform heat exchange between the refrigerant and the outside air taken into the inside of the outdoor unit 2 by rotation of the outdoor fan 27, as described later. One of the refrigerant gateways of the outdoor heat exchanger 23 is connected to the port “b” of the four-way valve 22 by the refrigerant pipe 62, as described above, and the other of the refrigerant gateways is connected to the liquid side closing valve 25 by an outdoor unit liquid pipe 63. The outdoor heat exchanger 23 functions as a condenser during the cooling operation, and functions as an evaporator during the heating operation, by switching of the four-way valve 22, as described later.
The expansion valve 24 is an electronic expansion valve to be driven by a pulse motor (not illustrated). Specifically, the opening degree of the expansion valve 24 is adjusted by the number of pulses added to the pulse motor. The opening degree of the expansion valve 24 during the heating operation is adjusted so that the discharge temperature, which is the temperature of the refrigerant discharged from the compressor 21, can become a predetermined target temperature.
The outdoor fan 27 is made of a resin material, and is arranged near the outdoor heat exchanger 23. The outdoor fan 27 has its central portion connected to the rotary shaft of a fan motor (not illustrated). As the fan motor rotates, the outdoor fan 27 is rotated. By rotation of the outdoor fan 27, outside air is taken into the inside of the outdoor unit 2 from a suction port (not illustrated) of the outdoor unit 2, and the outside air subjected to heat exchange with the refrigerant in the outdoor heat exchanger 23 is discharged to the outside of the outdoor unit 2 from a blowout port (not illustrated) of the outdoor unit 2.
In addition to the configuration described above, the outdoor unit 2 is provided with various sensors. As illustrated in
At an approximate middle of a refrigerant path (not illustrated) of the outdoor heat exchanger 23, a heat exchange temperature sensor 75 is provided that detects an outdoor heat exchange temperature, which is the temperature of the outdoor heat exchanger 23. Further, near the suction port (not illustrated) of the outdoor unit 2, an outside air temperature sensor 76 is provided that detects the temperature of outside air flowing into the inside of the outdoor unit 2, i.e. an outside air temperature.
Further, the outdoor unit 2 is provided with an outdoor unit control means 200. The outdoor unit control means 200 is mounted on a control board housed in an electric component box (not illustrated) of the outdoor unit 2. As illustrated in
The storage part 220 is composed of a flash memory, and stores control programs for the outdoor unit 2, detection values corresponding to detection signals from various sensors, control states of the compressor 21, the outdoor fan 27, etc. and so forth. Further, although not illustrated, the storage part 220 has stored in advance a table of the number of revolutions that specifies the numbers of revolutions of the compressor 21 in accordance with requested performance to be received from the indoor unit 3.
The communication part 230 is an interface for performing communication with the indoor unit 3. The sensor input part 240 takes in detection results obtained by the various sensors of the outdoor unit 2, and outputs these detection results to the CPU 210.
The CPU 210 takes in detection results from the respective sensors of the outdoor unit 2 described above via the sensor input part 240. Further, the CPU 210 takes in control signals transmitted from the indoor unit 3, via the communication part 230. The CPU 210 performs drive control over the compressor 21 and the outdoor fan 27, on the basis of the detection results and the control signals thus taken in and so forth. Further, the CPU 210 performs switching control over the four-way valve 22, on the basis of the detection results and the control signals thus taken in. Furthermore, the CPU 210 performs opening degree adjustment over the expansion valve 24, on the basis of the detection results and the control signals thus taken in.
<<Refrigerant Circuit of Indoor Unit>>
Next, with reference to
The indoor heat exchanger 31 serves to perform heat exchange between the refrigerant and the indoor air taken into the inside of the indoor unit 3 from a suction port (not illustrated) of the indoor unit 3 by rotation of the indoor fan 32, as described later. One of the refrigerant gateways of the indoor heat exchanger 31 is connected to the liquid pipe connector 33 by an indoor unit liquid pipe 67. The other of the refrigerant gateways of the indoor heat exchanger 31 is connected to the gas pipe connector 34 by an indoor unit gas pipe 68. The indoor heat exchanger 31 functions as an evaporator when the indoor unit 3 performs the cooling operation, and functions as a condenser when the indoor unit 3 performs the heating operation.
The indoor fan 32 is made of a resin material, and is arranged near the indoor heat exchanger 31. As the indoor fan 32 is rotated by a fan motor (not illustrated), indoor air is taken into the inside of the indoor unit 3 from the suction port (not illustrated) of the indoor unit 3, and the indoor air subjected to heat exchange with the refrigerant in the indoor heat exchanger 31 is blown out into the room from a blowout port (not illustrated) of the indoor unit 3.
In addition to the configuration described above, the indoor unit 3 is provided with various sensors. The indoor unit liquid pipe 67 is provided with a liquid-side temperature sensor 77 that detects the temperature of the refrigerant flowing into the indoor heat exchanger 31 or flowing out of the indoor heat exchanger 31. The indoor unit gas pipe 68 is provided with a gas-side temperature sensor 78 that detects the temperature of the refrigerant flowing out of the indoor heat exchanger 31 or flowing into the indoor heat exchanger 31. Further, near the suction port (not illustrated) of the indoor unit 3, a room temperature sensor 79 is provided that detects the temperature of indoor air flowing into the inside of the indoor unit 3, i.e., the room temperature.
Further, the indoor unit 3 is provided with an indoor unit control means 300. As illustrated in
The storage part 320 is composed of a flash memory, and stores control programs for the indoor unit 3, detection values corresponding to detection signals from various sensors, control states of the indoor fan 32 etc. and so forth. Further, although not illustrated, the storage part 320 has stored in advance a table of the number of revolutions or the like that specifies the numbers of revolutions of the indoor fan 32, including the number of revolutions for monitoring leakage of the refrigerant during the operation shutdown described later.
The communication part 330 is an interface for performing communication with the outdoor unit 2. The sensor input part 340 takes in detection results obtained by the various sensors of the indoor unit 3, and outputs these detection results to the CPU 310.
The CPU 310 takes in detection results from the respective sensors of the indoor unit 3 described above via the sensor input part 340. Further, the CPU 310 takes in control signals transmitted from the outdoor unit 2, via the communication part 330. The CPU 310 performs drive control over the indoor fan 32, including a drive for monitoring leakage of the refrigerant during the operation shutdown described later, on the basis of the detection results and the control signals thus taken in. Further, the CPU 310 calculates the temperature difference between a set temperature set by the user by operating a remote controller (not illustrated) and a room temperature detected by the room temperature sensor 79, and transmits requested performance based on the temperature difference thus calculated to the outdoor unit control means 200 of the outdoor unit 2 via the communication part 330.
<Operation of Refrigerant Circuit>
Next, with reference to
When the indoor unit 3 performs the heating operation, as illustrated in
The refrigerant with a high pressure discharged from the compressor 21 flows through the discharge pipe 61, and flows into the four-way valve 22. The refrigerant that has flowed into the port “a” of the four-way valve 22 flows from the port “d” of the four-way valve 22 through the outdoor unit gas pipe 64, and flows into the gas pipe 5 via the gas side closing valve 26. The refrigerant that has flowed through the gas pipe 5 flows into the indoor unit 3 via the gas pipe connector 34.
The refrigerant that has flowed into the indoor unit 3 flows through the indoor unit gas pipe 68, and flows into the indoor heat exchanger 31, where the refrigerant is subjected to heat exchange with the indoor air taken into the inside of the indoor unit 3 by rotation of the indoor fan 32, and is condensed. In this way, the indoor heat exchanger 31 functions as a condenser, and the indoor air subjected to heat exchange with the refrigerant in the indoor heat exchanger 31 is blown out from the blowout port (not illustrated) into the room, so as to achieve heating inside the room where the indoor unit 3 is installed.
The refrigerant that has flowed out of the indoor heat exchanger 31 flows through the indoor unit liquid pipe 67, and flows into the liquid pipe 4 via the liquid pipe connector 33. The refrigerant that has flowed through the liquid pipe 4 and flowed into the outdoor unit 2 through the liquid side closing valve 25 is decompressed when the refrigerant flows through the outdoor unit liquid pipe 63 and passes through the expansion valve 24. As described above, the opening degree of the expansion valve 24 during the heating operation is adjusted so that the discharge temperature of the compressor 21 can become a predetermined target temperature.
The refrigerant that has passed through the expansion valve 24 and flowed into the outdoor heat exchanger 23 is evaporated by being subjected to heat exchange with the outside air taken into the inside of the outdoor unit 2 by rotation of the outdoor fan 27. The refrigerant that has flowed out of the outdoor heat exchanger 23 into the refrigerant pipe 62 flows through the port “b” and the port “c” of the four-way valve 22 and the suction pipe 66, and is sucked by the compressor 21 and compressed again.
<Heat Exchanger>
The heat exchanger according to this embodiment is applicable to the indoor heat exchanger 31 of the indoor unit 3 and the outdoor heat exchanger 23 of the outdoor unit 2. However, in the following description, the heat exchanger will be explained as being applied to the indoor heat exchanger (which will be simply referred to as “heat exchanger”, hereinafter) 31 of the indoor unit 3, which functions as a condenser during the heating operation.
To explain in more detail, the flat tubes 40 are arranged along a direction in which the refrigerant flows between the pair of headers 12 (which may also be referred to as “longitudinal direction”), and each has a flat shape in a direction in which air flows (which may also be referred to as “shorter side direction”). Inside each of the flat tubes 40, a plurality of refrigerant flow passages are formed through which the refrigerant flows in the longitudinal direction. The plurality of flat tubes 40 are arranged in parallel with each other in the vertical direction with apertures S1 interposed therebetween for air to pass through, and their opposite ends are connected to the pair of headers 12. Specifically, the plurality of flat tubes 40 extending along the longitudinal direction are arrayed in the vertical direction at a predetermined array pitch Ph (the distance of each of the apertures S1 in the vertical direction), and their opposite ends are connected to the headers 12.
Each of the headers 12 has a cylindrical shape, inside of which refrigerant flow passages (not illustrated) are formed that serve to branch the refrigerant supplied to the heat exchanger 31 into portions flowing into the plurality of flat tubes 40, and to merge portions of the refrigerant flowing out of the plurality of flat tubes 40.
Each of the fins 50 has a flat plate shape, and the fins 50 are arranged in a multi-layered state in a direction intersecting with the flat tubes 40 in a front side view, and are arranged in parallel with each other with the apertures S1 interposed therebetween for air to pass through. Specifically, the plurality of fins 50 extending along the vertical direction are arrayed on the flat tubes 40 in the longitudinal direction thereof at a predetermined fin pitch Pv (the distance of each of the apertures S1 in the longitudinal direction). In the following description, with respect to the plurality of fins 50, two fins 50 horizontally adjacent to each other may be identified such that the fin on the left side in the drawings is referred to as “first fin 50a” and the fin on the right side in the drawings is referred to as “second fin 50b”.
<Flat Tube, Fin and Bulging Portion, and Fan>
Next, with reference to
As illustrated in
Since each first bulging portion 54 is provided in a state of being at least partly positioned on the corresponding intermediate region 52, condensed water deposited around the first flat tube 40a (not illustrated in
Thereafter, the condensed water flows down along an intermediate region side edge X1-Z1 connecting a first upper end X1 and a first lower end Z1, and a connection region side edge X2-Z2 connecting a second upper end X2 and a second lower end Z2. The condensed water that has reached the lower end edge Z1-Z2 flows to the second flat tube 40b or connection region 53, and is drained in sequence.
A second bulging portion 55 is further provided on the leeward side (on the right side in
In the above description, an explanation is give of a case where each ventilation direction is along the cross-sectional longitudinal direction of the flat tubes 40 (a direction from left to right in
Further, as illustrated in
In each case, the start point AU, which is a location where condensed water is accumulated, is at the connection region side end of a flat tube 40 or the second lower end Z2 of a first bulging portion 54. Each virtual line AF passes through at least one of the corresponding first bulging portion 54 and the second bulging portion 55, depending on the positional relationship, such as the inclination of the heat exchanger 31. The setting of virtual lines AF in accordance with various types of the indoor unit 3 (duct type, wall-mounted type, floor-standing type, vertical duct type, window type, ceiling suspension type, ceiling-embedded type, etc.) will be described later.
Here, as illustrated in
The size d2 of each droplet was measured for condensed water accumulated between the first fin 50a and the second fin 50b adjacent to each other as illustrated in
As illustrated in
Further, as illustrated in
Since the size d2 of each droplet becomes smaller as the contact angle θ is smaller, as indicated by the measurement results described above, it is preferable to set smaller the distance d1 between the first upper end X1 of each first bulging portion 54 and the lower side of the first notch portion 51a. In general, the fins 50 have been subjected to a hydrophilic treatment on the surface, and the contact angle θ of the droplet accumulated on the surface of the fins subjected to the hydrophilic treatment is set to 20° or less. Since the effect of the hydrophilic treatment on the fins 50 is gradually reduced by contamination and/or degradation, the distance d1 between the first upper end X1 of the first bulging portion 54 and the lower side of the first notch portion 51a is preferably set to deal with the size d2 of each droplet in the case of the contact angle θ=20° of a new product state.
In light of the above, on the basis of the measurement results described above, an approximate formula for the size d2 of each droplet according to the contact angle θ was created, and the size d2 of each droplet at the contact angle θ=20° was calculated. As a result, it has been found that, when the distance d1 is set to 4 mm or less, the first upper end X1 of the first bulging portion 54 comes into contact with the lower end of the droplet even with the contact angle θ=20°.
Therefore, the distance d1, illustrated in
After the droplet of condensed water reaches the first upper end X1 of the first bulging portion 54 in this way, the droplet wet-spreads on the upper end edge X1-X2 by the influence of surface tension, and further travels through the first upper end X1 and the second upper end X2 to the intermediate region side edge X1-Z1 and the connection region side edge X2-Z2. Since the droplet receives the influence of gravity in addition to the influence of surface tension, on the intermediate region side edge X1-Z1 and the connection region side edge X2-Z2, the droplets can be easily discharged by the first bulging portion 54 thus provided.
Further, as illustrated in
Since each first bulging portion 54 is arranged straddling the boundary between the corresponding intermediate region 52 and the connection region 53 of the individual fin 50 (see
<Ventilation Direction>
Next, with reference to
<<Suction Type>>
Here, examples are illustrated that use, as the indoor fan 32, a sirocco fan in the case of the duct type (
Of these examples, for the indoor unit 3 in which the heat exchanger 31 is composed of a plurality of heat exchanging units, as in the wall-mounted type (
<<Blowout Type>>
Here, examples are illustrated that use, as the indoor fan 32, a sirocco fan in the case of the duct type (
Of these examples, for the indoor unit 3 in which the minimum cross-sectional area portion on the leeward side of the heat exchanger 31 serves as a blowout port from the heat exchanger 31, as in the duct type (
<Effect of Embodiment>
The heat exchanger 31 according to this embodiment can suppress the dew splash of condensed water accumulated on the surface of the fins 50 or flat tubes 40. Specifically, the first bulging portion 54 is provided on each of the intermediate regions 52 of the fins 50 positioned below the flat tubes 40, and condensed water around the flat tubes 40 is thereby drained. In addition, each resultant droplet is made smaller, and the second bulging portion 55 is further provided on the connection region 53 of the fins 50, so that the flow velocity of the air flows becomes lower, and the drag applied to condensed water in each ventilation direction (the force received from each air flow in the ventilation direction) decreases. As a result, it is possible to suppress dew splash in which condensed water is scattered from the heat exchanger 31 toward the leeward side. Further, the ventilation directions in the ventilation flue 35 are set by virtual lines AF, each of which extends from a start point AU at the connection region side end of a flat tube 40, as a location where condensed water is accumulated, to an end point AD at the center of the minimum cross-sectional area portion on the leeward side of the heat exchanger 31, as a site where the static pressure is lowest. As a result, it is possible to set the positions of each first bulging portion 54 and the second bulging portion 55, in accordance with the direction of the drag applied to condensed water inside the ventilation flue 35.
1 air conditioner
2 outdoor unit
3 indoor unit
4 liquid pipe
5 gas pipe
10 refrigerant circuit
10
a outdoor unit refrigerant circuit
10
b indoor unit refrigerant circuit
12 header
21 compressor
22 four-way valve
23 outdoor heat exchanger
24 expansion valve
25 liquid side closing valve
26 gas side closing valve
27 outdoor fan
31 indoor heat exchanger
32 indoor fan
33 liquid pipe connector
34 gas pipe connector
35 ventilation flue
40 flat tube
50 fin
51 notch portion
52 intermediate region
53 connection region
54 first bulging portion
55 second bulging portion
61 discharge pipe
62 refrigerant pipe
63 outdoor unit liquid pipe
64 outdoor unit gas pipe
66 suction pipe
67 indoor unit liquid pipe
68 indoor unit gas pipe
71 discharge pressure sensor
72 suction pressure sensor
73 discharge temperature sensor
74 suction temperature sensor
75 heat exchange temperature sensor
76 outside air temperature sensor
77 liquid-side temperature sensor
78 gas-side temperature sensor
79 room temperature sensor
200 outdoor unit control means
210 CPU
220 storage part
230 communication part
240 sensor input part
300 indoor unit control means
310 CPU
320 storage part
330 communication part
340 sensor input part
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-058395 | Mar 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/003638 | 1/31/2020 | WO | 00 |
