WO2022201514A1

WO2022201514A1 - Air conditioning device

Info

Publication number: WO2022201514A1
Application number: PCT/JP2021/012941
Authority: WO
Inventors: 皓亮宮脇; 智哉福井; 健一迫田
Original assignee: 三菱電機株式会社
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2022-09-29
Also published as: US20240175586A1; JPWO2022201514A1; JP7442731B2; EP4317811A4; CN117043519A; EP4317811A1

Abstract

Provided is an air conditioning device (200) having a heat exchanger (10) that switches between being an evaporator and being a condenser, the air conditioning device characterized in that the heat exchanger (10) comprises: a first heat exchanger (21) having a first header (213) which is partitioned into a plurality of chambers and to which one end of a plurality of first heat transfer pipes (212) are connected, and a second header (214) which extends in the horizontal direction and to which the other end of the plurality of first heat transfer pipes (212) are connected; a second heat exchanger (22) having a plurality of second heat transfer pipes (222), a third header (223) which extends in the horizontal direction and to which one end of the plurality of second heat transfer pipes (222) are connected, and a fourth header (224) which extends in the horizontal direction and to which the other end of the plurality of second heat transfer pipes (222) are connected; and a connection pipe (12) that connects the first heat exchanger (21) and the second heat exchanger (22), wherein the length of the plurality of first heat transfer pipes (212) is longer than the length of the plurality of second heat transfer pipes (222).

Description

air conditioner

The present disclosure relates to an air conditioner equipped with a heat exchanger that functions both as a condenser and as an evaporator.

It is known that a flat tube with a flat cross section is used as a heat transfer tube, and a heat exchanger that exchanges heat between a refrigerant flowing inside the flat tube and a fluid outside the flat tube is used in an air conditioner. For example, Patent Document 1 discloses a heat exchanger functioning as a condenser in an air conditioner, in which both ends of a plurality of flat tubes are connected to a pair of horizontally extending headers, and the inside of the headers is partitioned by a partition plate. A heat exchanger is shown in which the refrigerant flows meanderingly through flat tubes.

In Patent Document 1, the number of flat tubes from the inlet to the outlet is gradually reduced, and the flow channel cross-sectional area of the heat exchanger downstream of the refrigerant flow can be made smaller than the flow channel cross-sectional area of the heat exchanger upstream of the refrigerant flow. Proposed. As a result, the flow velocity of the refrigerant on the downstream side is increased, suppressing a decrease in heat transfer coefficient and maintaining high heat exchange performance.

JP 2015-230129 A

In an air conditioner that switches between cooling and heating, the heat exchanger that functions as a condenser also functions as an evaporator when the operation switches. A heat exchanger using flat tubes as in Patent Document 1 is suitable for reducing the amount of refrigerant, ie, so-called refrigerant saving. However, when the heat exchanger of Patent Document 1 functions as an evaporator, the cross-sectional area of the flow path on the side where the refrigerant flows is smaller than the cross-sectional area of the flow path on the side where the refrigerant flows out. Refrigerant pressure loss may increase. When the refrigerant pressure loss increases, the saturation temperature of the refrigerant decreases and the air conditioning performance deteriorates.

Therefore, an object of the present disclosure is to realize an air conditioner equipped with a heat exchanger capable of achieving both refrigerant saving and high performance.

The air conditioner of the present disclosure is
A heat exchanger in which a compressor, a condenser, a decompression device, and an evaporator are connected by piping to circulate refrigerant, and the function is switched between the evaporator and the condenser by switching the direction of refrigerant flow; and a fan that generates an airflow so that is sent to the heat exchanger,
The heat exchanger is
A plurality of first heat transfer tubes and a first heat transfer tube extending in the horizontal direction and partitioned into a plurality of chambers including a first chamber and a second chamber, to which one end of the plurality of first heat transfer tubes is connected a first heat exchanger having one header and a second header extending horizontally to which the other ends of the plurality of first heat transfer tubes are connected;
a plurality of second heat transfer tubes; a third header extending horizontally to which one ends of the plurality of second heat transfer tubes are connected; and a horizontally extending other end of the plurality of second heat transfer tubes. a second heat exchanger having a connected fourth header;
a connection pipe that connects one of the first header and the second header of the first heat exchanger and the third header of the second heat exchanger;
with
In the operation in which the heat exchanger functions as the evaporator, the refrigerant to be evaporated flows from the pipe into the first chamber of the first header, flows from the first chamber to the second header, The plurality of first heat transfer pipes are connected so as to flow from the second header to the second chamber of the first header, and the refrigerant that has passed through the first heat exchanger passes through the connection pipe to the second heat exchange pipe. The plurality of second heat transfer tubes are connected so that the refrigerant flows from the third header to the fourth header after flowing into the third header of the vessel, and the refrigerant that has passed through the second heat exchanger is compressed into the compression The pipe is connected so as to be sucked into the machine,
In the operation in which the heat exchanger functions as the condenser, the refrigerant to be condensed passes through the second heat exchanger from the pipe, and then passes through the connection pipe to the first header of the first heat exchanger. the piping is connected so that the refrigerant that flows into one of the plurality of chambers or the second header and has passed through the first heat exchanger flows out of the first chamber of the first header;
The length of the plurality of first heat transfer tubes is longer than the length of the plurality of second heat transfer tubes.

According to the air conditioner according to the present disclosure, the pressure loss is reduced in the operation in which the first heat exchanger and the second heat exchanger function as evaporators, and the first heat exchanger and the second heat exchanger are In the operation of functioning as a condenser, the refrigerant density is reduced, and both high performance and refrigerant saving can be achieved.

1 is a schematic diagram showing the configuration of an air conditioner according to Embodiment 1. FIG. 2 is a schematic diagram of an indoor heat exchanger provided in the air conditioner according to Embodiment 1. FIG. 1 is a schematic diagram showing an air conditioner having an indoor heat exchanger according to Embodiment 1. FIG. 4 is a diagram showing the relationship between the evaporator performance of the indoor heat exchanger according to Embodiment 1 and the heat transfer tube length ratio. FIG. 1 is a schematic diagram showing an air conditioner having an indoor heat exchanger according to Embodiment 1. FIG. 4 is a diagram showing the relationship between the amount of refrigerant in the indoor heat exchanger according to Embodiment 1 and the length ratio of heat transfer tubes. FIG. FIG. 4 is a schematic diagram of a first modification of the indoor heat exchanger according to Embodiment 1; FIG. 5 is a schematic diagram of a second modification of the indoor heat exchanger according to Embodiment 1; FIG. 6 is a schematic diagram showing an indoor unit according to Embodiment 2; FIG. 10 is a schematic diagram showing refrigerant flowing through connection pipes of the indoor heat exchangers of FIG. 9 ; FIG. 11 is a perspective view showing an internal configuration of an indoor unit according to Embodiment 3; FIG. 12 is a schematic diagram of the AA cross section of the indoor unit of FIG. 11; FIG. 3 is a schematic diagram of an indoor unit taken along line AA of a comparative example; FIG. 11 is a schematic diagram for explaining the relationship between the indoor fan of the indoor unit according to Embodiment 3 and the wind speed; 14. It is a figure which shows the relationship between the position of the rotating shaft direction of the indoor fan in FIG. 14, and wind speed, and the relationship between the position of the rotating shaft of the indoor fan in the circumferential direction, and wind speed. FIG. 10 is a schematic diagram showing a refrigerant channel configuration of a heat exchanger according to Embodiment 3; FIG. 11 is a characteristic diagram showing an improvement effect on the coolant channel configuration according to Embodiment 3; FIG. 11 is a perspective view of an indoor unit according to Embodiment 4; FIG. 19 is a schematic diagram of the BB cross section of the indoor unit of FIG. 18; FIG. 20 is a schematic diagram showing the wind speed distribution of the airflow flowing through the indoor unit of FIG. 19; FIG. 11 is a schematic diagram showing an outline of a cross section of an indoor unit according to Embodiment 5; FIG. 11 is a cross-sectional view schematically showing an AA cross section of an indoor unit 202 according to Embodiment 5;

An embodiment of an air conditioner according to the present disclosure will be described below. In addition, the form represented by drawing is an example, and does not limit this indication. In addition, the same reference numerals in each drawing are the same or equivalent, and this is common throughout the specification. Furthermore, in the drawings below, the size relationship of each component may differ from the actual size.

Embodiment 1
<Configuration of air conditioner 200>
FIG. 1 is a schematic diagram showing the configuration of an air conditioner 200 according to Embodiment 1. FIG. The air conditioner 200 is a heat pump device that includes a circuit in which a refrigerant circulates and transfers heat by means of a refrigeration cycle in which the refrigerant compresses, condenses, expands, and evaporates in the circuit. In such a heat pump device, a compressor, a condenser, a decompression device such as a throttle device, and an evaporator are connected by pipes to circulate the refrigerant. As shown in FIG. 1 , an air conditioner 200 according to Embodiment 1 has an outdoor unit 201 and an indoor unit 202 . The air conditioner 200 performs cooling operation and heating operation by switching the flow direction of the refrigerant.

The outdoor unit 201 is provided with an outdoor blower 13a, a compressor 14, a four-way valve 15, an outdoor heat exchanger 16, and a throttle device 17. The indoor unit 202 includes an indoor heat exchanger 10 including a first heat exchanger 21 and a second heat exchanger 22, and an indoor fan 13b. The indoor heat exchanger 10 is a heat exchanger that exchanges heat between indoor air and refrigerant. The indoor blower 13 b is a blower that generates an airflow so that indoor air is sent to the indoor heat exchanger 10 . The outdoor unit 201 is an example of a heat source side heat exchanger. Also, the indoor unit 202 is an example of a user-side heat exchanger.

The four-way valve 15 and the outdoor heat exchanger 16 are connected by a pipe 11a. The outdoor heat exchanger 16 and the expansion device 17 are connected by a pipe 11b. The expansion device 17 and the first heat exchanger 21 of the indoor heat exchanger 10 are connected by a pipe 11c. The expansion device 17 is a decompression device that reduces the pressure after passage of the refrigerant from the pressure before passage by reducing the cross-sectional area through which the refrigerant passes. The second heat exchanger 22 of the indoor heat exchanger 10 and the four-way valve 15 are connected by a pipe 11d.

Refrigerant flows through the compressor 14, the four-way valve 15, the outdoor heat exchanger 16, the expansion device 17, and the indoor heat exchanger 10, thereby forming a refrigeration cycle. The four-way valve 15 is a switching valve that switches the flow direction of the refrigerant discharged from the compressor 14, and the flow direction of the refrigerant is directed to the outdoor heat exchanger 16 through the pipe 11a and the indoor heat exchange through the pipe 11d. The flow is switched to either one of the flows toward the vessel 10. Switching between the cooling operation and the heating operation of the air conditioner 200 is performed by switching the direction of the refrigerant flow through the four-way valve 15 . Instead of the four-way valve 15, this switching valve can also be configured by combining other valves, such as a combination of a plurality of two-way valves, piping, and the like.

During the cooling operation of the air conditioner 200, the indoor heat exchanger 10 functions as an evaporator, and the outdoor heat exchanger 16 functions as a condenser. acts as an evaporator. In other words, the air conditioner 200 includes a heat exchanger whose function is switched between an evaporator and a condenser when the refrigerant flows in the opposite direction.

<Configuration of indoor heat exchanger 10>
FIG. 2 is a schematic diagram of the indoor heat exchanger 10 provided in the air conditioner 200 according to Embodiment 1. FIG. As shown in FIG. 2, the indoor heat exchanger 10 includes a first heat exchanger 21, a second heat exchanger 22, and a connection pipe 12 that connects the first heat exchanger 21 and the second heat exchanger 22. , is composed of

The first heat exchanger 21 has a plurality of first heat transfer tubes 212, a plurality of first fins 211, a first header 213, and a second header 214. The second heat exchanger 22 also has a plurality of second heat transfer tubes 222 , a plurality of second fins 221 , a third header 223 and a fourth header 224 . The first heat exchanger 21 and the second heat exchanger 22 are connected by a connecting pipe 12 . The first heat transfer tube 212 and the second heat transfer tube 222 are heat transfer tubes through which the refrigerant passes and exchange heat with the surrounding air outside. Each of the first heat transfer tube 212 and the second heat transfer tube 222 is arranged with a gap from the adjacent heat transfer tube, and air passes through the gap. In addition, the first header 213, the second header 214, the third header 223, and the fourth header 224 distribute the refrigerant to a plurality of heat transfer tubes such as the plurality of first heat transfer tubes 212 or the plurality of second heat transfer tubes 222, or distribute the refrigerant to a plurality of heat transfer tubes. collect refrigerant from the heat transfer tubes of Refrigerant flows into or out of either the first header 213 or the second header 214 of the first heat exchanger 21 or the third header 223 or the fourth header 224 of the second heat exchanger 22. Plumbing is connected.

The connection pipe 12 connects the first heat exchanger 21 and the second heat exchanger 22 in series. That is, the refrigerant that has passed through either one of the first heat exchanger 21 and the second heat exchanger 22 flows into the other through the connecting pipe 12 . When both the first heat exchanger 21 and the second heat exchanger 22 function as evaporators, refrigerant containing a liquid phase flows into the second heat exchanger 22 through the first heat exchanger 21 and the connecting pipe 12. do. When both the first heat exchanger 21 and the second heat exchanger 22 function as condensers, refrigerant containing a gas phase flows into the first heat exchanger 21 through the second heat exchanger 22 and the connecting pipe 12. do. When functioning as an evaporator, the header connected to the pipes so that the refrigerant containing the liquid phase flows into the first heat exchanger 21 is arranged to flow into the first header 213 and the second heat exchanger 22. A third header 223 is a header to which the connection pipe 12 is connected. Also, in this case, the refrigerant flows into the second heat exchanger 22 from the connecting pipe 12 connected to the second header 214 of the first heat exchanger 21, and the refrigerant flows from the fourth header 224 of the second heat exchanger 22. is configured to flow out to the outside, but it is not necessarily limited to this configuration. Refrigerant may flow into the second heat exchanger 22 from the connecting pipe 12 connected to the first header 213 of the first heat exchanger 21, and may flow outside from the third header 223 of the second heat exchanger 22. A configuration in which the refrigerant flows out may be adopted.

The multiple first heat transfer tubes 212 of the first heat exchanger 21 are flat tubes, and are alternately stacked with the multiple first fins 211 . The multiple first fins 211 are, for example, corrugated fins. The flattened tube has a flattened shape with one longitudinal section perpendicular to its extending direction. An air conditioner in which a high-pressure refrigerant flows generally uses a multi-hole pipe in which the internal flow path is divided into a plurality of pieces in the longitudinal direction. A corrugated fin is formed by corrugating a metal sheet with good thermal conductivity such as aluminum. The first fins 211 and the second fins 221 increase the heat exchange area of the first heat exchanger 21 to improve heat exchange between the air passing around the flat tubes and the heat transfer tubes. The plurality of first heat transfer tubes 212 are arranged in parallel in the longitudinal direction and spaced apart in the widthwise direction, and the corrugated tops of the corrugated fins are joined to the surfaces of the flattened tubes facing the spaced apart.

The first header 213 and the second header 214 of the first heat exchanger 21 extend horizontally. One ends of the plurality of first heat transfer tubes 212 are connected to the first header 213 , and the other ends of the plurality of first heat transfer tubes 212 are connected to the second header 214 . The first header 213 and the second header 214 have a tubular structure in which the internal flow channel cross-sectional area is larger than the internal flow channel cross-sectional area of the first heat transfer tube 212 . Each of the plurality of first heat transfer tubes 212 is a tube extending in the vertical direction, and they are horizontally spaced and arranged side by side.

The first heat exchanger 21 and the second heat exchanger 22 are not in a windward-downward relationship with respect to the air blown from the indoor fan 13b or the like, that is, they are shifted from each other when viewed from the fan or the windward side of the air duct. are placed in the same position. Typically, one of the first header 213 and the second header 214 is arranged adjacent to the one of the third header 223 and the fourth header 224 so that the first header 213 and the second header 214 are separated. The other is arranged far away from the other of the third header 223 and the fourth header 224 .

The multiple second heat transfer tubes 222 of the second heat exchanger 22 are flat tubes, and are alternately stacked with the multiple second fins 221 . The multiple second fins 221 are, for example, corrugated fins. Like the first fins 211 , the second fins 221 expand the heat exchange area of the second heat exchanger 22 . Either or both of the first heat exchanger 21 and the second heat exchanger 22 may use plate fins or the like instead of corrugated fins.

The third header 223 and fourth header 224 of the second heat exchanger 22 extend horizontally. One ends of the plurality of second heat transfer tubes 222 are connected to the third header 223 , and the other ends of the plurality of second heat transfer tubes 222 are connected to the fourth header 224 . The third header 223 and the fourth header 224 have a tubular structure in which the inner cross-sectional area of the flow path is larger than the cross-sectional area of the inner flow path of the second heat transfer tube 222 . The second heat exchanger 22 has a structure similar to that of the first heat exchanger 21, but differs in the length of the heat transfer tubes, the inside of the header, etc., as will be described later. Each of the plurality of second heat transfer tubes 222 is a tube extending in the vertical direction, and they are arranged side by side at intervals in the horizontal direction. In addition, in FIG. 1, the plurality of first heat transfer tubes 212 and the plurality of second heat transfer tubes 222 are shown as being on a plane, but the first heat transfer tubes 212 and the second heat transfer tubes 222 are configured to extend in the vertical direction. is not limited to At least one of the first heat transfer tube 212 and the second heat transfer tube 222 may be configured to extend obliquely or extend in directions having an angle with each other.

The space inside the first header 213 is partitioned into a plurality of rooms including a first room 213a and a second room 213b by the partition member 4. The space partitioned by the partition member 4 is called a room, and when the rooms partitioned by each header are individually called, they will be described as the first room, the second room, and the like. In the illustrated example, the first header 213 is partitioned into three chambers from a first chamber 213a to a third chamber 213c. The space inside the second header 214 is partitioned into a plurality of chambers from the first chamber 214a to the third chamber 214c by the partition member 4 in the illustrated example.

The space inside the third header 223 is partitioned by the partition member 4 into a first chamber 223a and a second chamber 223b. The fourth header 224 is partitioned by the partition member 4 into a first chamber 224a and a second chamber 224b. Although the above is an example in which the interior of all headers is partitioned into a plurality of rooms by partition members 4, the interior spaces of some headers may be configured as a single room without being partitioned. The number of rooms divided between the first header 213 and the second header 214 may be different, and the number of rooms divided between the third header 223 and the fourth header 224 may be different.

The connection pipe 12 connects either the first header 213 or the second header 214 of the first heat exchanger 21 and the third header 223 of the second heat exchanger 22 . In the illustrated example, the connecting pipe 12 connects the fourth chamber 213 d of the first header 213 and the first chamber 223 a of the third header 223 . In the example of the drawing, the fourth chamber 213d of the first header 213 and the first chamber 223a of the third header 223 to which the connection pipe 12 is connected are arranged horizontally in the first header 213 and the third header 223, respectively. at the same end. In this way, if the connecting pipes 12 are configured to connect the chambers of the headers at the ends on the same side, the length of the connecting pipes 12 can be shortened. In the figure,

pipes

11c and 11d are connected so that the refrigerant flows in and out of the first heat exchanger 21 and the second heat exchanger 22 from one side in the horizontal direction. shows a configuration in which the chambers of the headers at the ends of the are connected. The first chamber 213a of the first header 213 is a chamber at one end of the first header 213 in the horizontal direction, and the connecting pipe 12 is connected to any one of the chambers of the first header 213 at the other end in the horizontal direction. or connect any of the plurality of rooms of the second header 214 at the other end in the horizontal direction to the third header 223 . With the above configuration, the connection pipe 12 can be shortened, but the connection pipe 12 or the

pipes

11c and 11d may be connected to the rooms at the opposite ends in the horizontal direction. Also, the connection pipe 12 may be connected to any one of the plurality of rooms of the third header 223 .

In the operation in which the indoor heat exchanger 10 functions as an evaporator, the refrigerant to be evaporated flows into the first chamber 213a of the first header 213 of the first heat exchanger 21 through the pipe 11c. Then, the refrigerant flows into the first chamber 214a of the second header 214 from the first heat transfer pipes 212 connected to the first chamber 213a, changes its flow direction in the first chamber 214a, and flows out of the second header 214. do. Furthermore, the refrigerant flows from the second header 214 into the second chamber 213b of the first header 213 through the first heat transfer tubes 212 connected to the second chamber 213b of the first header 213 . Of the first heat transfer tubes 212 connected to the first chamber 214a of the second header 214, the first heat transfer pipes 212 connected to the first chamber 213a of the first header 213 and the second heat transfer pipes 213b of the first header 213 The flow direction of the refrigerant is upside down.

The refrigerant changes its flow direction in the second chamber 213b of the first header 213, flows out from the second chamber 213b, and flows into the second chamber 214b of the second header 214. Then, the flow direction of the refrigerant is reversed in the second chamber 214 b , flows out from the second chamber 214 b of the second header 214 , and flows into the third chamber 213 c of the first header 213 . Then, the flow direction of the refrigerant is reversed in the third chamber 213 c , flows out from the third chamber 213 c of the first header 213 , and flows into the third chamber 214 c of the second header 214 . After that, the refrigerant flows from the third chamber 213 c of the first header 213 to the first chamber 223 a of the third header 223 of the second heat exchanger 22 via the connecting pipe 12 . The refrigerant flows from the second heat transfer pipes 222 connected to the first chambers 223a of the third header 223 into the first chambers 224a of the fourth header 224, and flows in the first chambers 224a of the fourth header 224. It is diverted and flows into the second chamber 223 b of the third header 223 . Then, the refrigerant changes its flow direction in the second chamber 223 b and flows into the second chamber 224 b of the fourth header 224 . After that, the refrigerant flows out from the pipe 11 d connected to the second chamber 224 b of the fourth header 224 . A pipe 11 d is connected so that the refrigerant that has passed through the second heat exchanger 22 is sucked into the compressor 14 .

In the operation in which the indoor heat exchanger 10 functions as a condenser, the refrigerant flows in the opposite direction as in the case of the evaporator. That is, the refrigerant flows from the pipe 11 d into the second chamber 224 b of the fourth header 224 of the second heat exchanger 22 and flows out of the first chamber 213 a of the first header 213 of the first heat exchanger 21 . After the refrigerant discharged from the compressor 14 and to be condensed passes through the second heat exchanger 22 from the pipe 11d, it passes through the connecting pipe 12 to one of the plurality of chambers of the first header 213 of the first heat exchanger 21. , or into the second header 214 . In the drawing, the connecting pipe 12 is connected from the first chamber 223a of the third header 223 of the second heat exchanger 22 to the third chamber 213c of the first header 213, but is connected to the second header 214. good too. The refrigerant condensed through the first heat exchanger 21 flows out from the first chamber 213 a of the first header 213 and flows toward the expansion device 17 .

As described above, the refrigerant entering from the room at one end of the horizontal direction of the header is diverted in direction between the pair of headers connected by the first heat transfer tubes 212, thereby making it horizontal to the inflow side. proceed in a meandering manner toward the opposite direction. After flowing to the room on the farthest opposite side, the refrigerant flows through the connecting pipe 12 to the other heat exchanger or to the outside through the

pipe

11c or 11d.

The sum of the number of rooms in the third header 223 of the second heat exchanger 22 and the number of rooms in the fourth header 224 is equal to the number of rooms in the first header 213 of the first heat exchanger 21 and the number of rooms in the second header less than the sum of 214 rooms. Therefore, the number of times the flow direction of the refrigerant changes in the second heat exchanger 22 is smaller than the number of times the flow direction of the refrigerant changes in the first heat exchanger 21 .

The number of the plurality of first heat transfer tubes 212 and the number of the plurality of second heat transfer tubes 222 are the same. The plurality of first heat transfer tubes 212 and the plurality of second heat transfer tubes 222 have the same channel cross-sectional area per tube. The first header 213, second header 214, third header 223, and fourth header 224 all have the same length. The first header 213 and the second header 214 use pipes of the same diameter, and therefore their internal spaces are basically the same in volume except for slight differences in the connecting parts with the partition member 4 and each pipe. is. Similarly, the internal spaces of the third header 223 and the fourth header 224 are basically the same volume. If the internal spaces of the first header 213, the second header 214, the third header 223, and the fourth header 224 have basically the same volume, the structure will be simple. In addition, the internal space of the third header 223 and the fourth header 224 of the second heat exchanger may be larger than the internal space of the first header 213 and the second header 214, so that the third header 223 and the fourth header The pipe diameter of the header 224 may be larger than the pipe diameters of the first header 213 and the second header 214 .

The length L1 of the multiple _first heat transfer tubes 212 is longer than the length L2 of the multiple _second heat transfer tubes 222 . The length L1 of the first heat transfer tube 212 is the length from _one end of the first heat transfer tube 212 connected to the first header 213 to the other end of the first heat transfer tube 212 connected to the second header 214. Say. The length L2 of the _second heat transfer tubes 222 is the length from one end of the second heat transfer tubes 222 connected to the third header 223 to the other end of the second heat transfer tubes 222 connected to the fourth header 224. say.

The number of first heat transfer tubes 212 connected to each of the first chamber 213a to the third chamber 213c of the first header 213 is not the same in the rooms of the first header 213 (the first chamber 213a to the third chamber 213c). not different. In addition, the number of first heat transfer tubes 212 connected to each of the first to third chambers 214a to 214c of the second header 214 is the same in the rooms of the second header 214 (first to third chambers 214a to 214c). but different. That is, the number of the plurality of first heat transfer tubes 212 connected to the first chamber 213a to the third chamber 213c of the first header 213 and the first chamber 214a to the third chamber 214c of the second header 214 is adjusted. It is As a result, the cross-sectional area of the flow path of the refrigerant does not decrease before and after the direction of flow of the refrigerant changes during operation of the condenser, and remains the same or increases.

In addition, the average number of the second heat transfer tubes 222 connected to the rooms of the third header 223 (the first room 223a and the room 223b) is is greater than the average number of first heat transfer tubes 212 connected to .

The first chamber 213a of the first header 213 is connected to the pipe 11c, the second chamber 224b of the fourth header 224 is connected to the pipe 11d, and the connection pipe 12 is connected. In the third chamber 214c of the second header 214 and the first chamber 223a of the third header 223, since the refrigerant does not fold back between the connected heat transfer tubes, the length of the room is longer than that of the adjacent rooms where the folding occurs. length is getting shorter.

Next, the operation of the indoor heat exchanger 10 will be explained.

<During cooling operation>
FIG. 3 is a schematic diagram showing an air conditioner 200 having the indoor heat exchanger 10 according to Embodiment 1. FIG. In FIG. 3, arrows indicate the flow of refrigerant during cooling operation. In cooling operation of the air conditioner 200, the indoor heat exchanger 10 functions as an evaporator, and the outdoor heat exchanger 16 functions as a condenser.

The refrigerant becomes a high-temperature and high-pressure gas in the compressor 14, flows through the four-way valve 15 into the outdoor heat exchanger 16 mounted on the outdoor unit 201, heats the heat to the outdoor air blown by the outdoor fan 13a, and becomes a liquid phase. It becomes a refrigerant or a liquid-based refrigerant. Then, the refrigerant is depressurized by the expansion device 17, flows into the first heat exchanger 21 of the indoor heat exchanger 10 of the indoor unit 202, and is the indoor air blown by the indoor fan 13b in the first heat exchanger 21. absorb heat from Then, while flowing from the first heat exchanger 21 of the indoor heat exchanger 10 to the second heat exchanger 22 of the indoor heat exchanger 10, the refrigerant changes from the low-temperature, low-pressure two-phase refrigerant to the low-pressure gas refrigerant. , and returns to the compressor 14 again via the four-way valve 15 .

FIG. 4 is a diagram showing the relationship between the evaporator performance of the indoor heat exchanger 10 according to Embodiment 1 and the heat transfer tube length ratio. In FIG. 4, the vertical axis indicates the evaporator performance, and the horizontal axis indicates the heat transfer tube length ratio.

The heat transfer tube length ratio is the ratio of the length L ₁ of the first heat transfer tube 212 to the total length L ₁ +L ₂ of the first heat transfer tube 212 and the second heat transfer tube 222 .

As shown in Fig. 4, when the heat transfer tube length ratio increases, it becomes difficult to reduce the pressure loss and the evaporator performance improves. Further, when the heat transfer tube length ratio becomes small, the evaporator performance deteriorates due to the reduction in pressure loss.

When the indoor heat exchanger 10 functions as an evaporator, the refrigerant decompressed by the expansion device 17 absorbs heat from the indoor air in the first heat transfer pipe 212 of the first heat exchanger 21, and the dryness increases. Then, it flows through the second heat transfer tube 222 of the second heat exchanger 22 .

At this time, the volumetric flow rate of the refrigerant flowing through the second heat exchanger 22 is larger than that of the first heat exchanger 21 . Therefore, when the length L2 of the _second heat transfer tube 222 is longer than the length L1 of the _first heat transfer tube 212, that is, when the heat transfer tube length ratio is small, the pressure in the second heat transfer tube 222 is Evaporator performance is reduced because losses increase and the saturation temperature in the indoor heat exchanger 10 decreases.

On the other hand, when the length L2 of the _second heat transfer tube 222 is shorter than the length L1 of the _first heat transfer tube 212, that is, when the heat transfer tube length ratio is large, a refrigerant with a high degree of dryness flows. shorter route. Therefore, the pressure loss in the second heat transfer pipes 222 is reduced, the saturation temperature in the indoor heat exchanger 10 is increased, and the performance of the evaporator can be improved.

<During heating operation>
FIG. 5 is a schematic diagram showing an air conditioner 200 having the indoor heat exchanger 10 according to Embodiment 1. FIG. In FIG. 5, arrows indicate the flow of refrigerant during heating operation.

In the heating operation of the air conditioner 200, the indoor heat exchanger 10 functions as a condenser, and the outdoor heat exchanger 16 functions as an evaporator.

The refrigerant becomes a high-temperature and high-pressure gas in the compressor 14, flows into the indoor heat exchanger 10 of the indoor unit 202 via the four-way valve 15, and enters the first heat exchanger 21 and the second heat exchanger of the indoor heat exchanger 10. At 22, the heat is radiated to the indoor air blown by the indoor fan 13b, and the refrigerant flows out as a liquid-phase refrigerant or a liquid-based refrigerant. Then, the refrigerant is depressurized by the expansion device 17, absorbs heat from the outside air blown by the outdoor fan 13a in the outdoor heat exchanger 16 of the outdoor unit 201, and changes from a low-temperature, low-pressure two-phase refrigerant to a low-pressure gas refrigerant. The refrigerant then flows out from the outdoor heat exchanger 16 and returns to the compressor 14 via the four-way valve 15 .

FIG. 6 is a diagram showing the relationship between the amount of refrigerant in the indoor heat exchanger 10 according to Embodiment 1 and the heat transfer tube length ratio. In FIG. 6, the vertical axis indicates the refrigerant amount, and the horizontal axis indicates the heat transfer tube length ratio.

As shown in FIG. 6, when the heat transfer tube length ratio is small, the refrigerant density increases, so the amount of refrigerant in the indoor heat exchanger 10 also increases. Further, when the heat transfer tube length ratio increases, the refrigerant density decreases, so the amount of refrigerant in the indoor heat exchanger 10 also decreases.

When the indoor heat exchanger 10 functions as a condenser, the dry refrigerant flows from the second heat exchanger 22 and passes through the second heat exchanger 22 and the first heat exchanger 21 while radiating heat to the indoor air. flow. Then, the refrigerant flows out of the first heat exchanger 21 in a state of reduced dryness.

At this time, if the dryness of the refrigerant in the third header 223 and the fourth header 224 of the second heat exchanger 22 is low, the average refrigerant density in the third header 223 and the fourth header 224 increases. Then, since the amount of refrigerant in the third header 223 and the fourth header 224 increases, the amount of refrigerant in the indoor heat exchanger 10 also increases.

On the other hand, by making the length L1 of the _first heat transfer tube 212 longer than the length L2 of the _second heat transfer tube 222, heat transfer in the first heat exchanger 21 is promoted, The dryness in the third header 223 and the fourth header 224 of the second heat exchanger 22 increases. As a result, the average refrigerant density of the indoor heat exchanger 10 is reduced, and the amount of refrigerant is reduced.

Thus, when the indoor heat exchanger 10 functions as an evaporator, the saturation temperature in the indoor heat exchanger 10 rises, and when the indoor heat exchanger 10 functions as a condenser, the indoor heat exchanger The average refrigerant density at 10 is reduced.

As a result, both the high performance of the air conditioner 200 and the refrigerant saving can be achieved.

The number of partition members 4 that partition the internal spaces of the first header 213, the second header 214, the third header 223, and the fourth header 224, and the number of rooms partitioned by the partition members 4 can be changed as appropriate. can. Also, the third header 223 and the fourth header 224 may be configured to have only one room without the partition member 4 .

However, the sum of the number of rooms in the third header 223 of the second heat exchanger 22 and the number of rooms in the fourth header 224 is equal to the number of rooms in the first header 213 of the first heat exchanger 21 and the number of rooms in the fourth header 224 2 header 214 less than the sum of the number of rooms. Alternatively, the number of rooms in the first header 213 or the second header 214 of the first heat exchanger 21 connected by the connection pipes 12 is greater than the number of rooms in the third header 223 of the second heat exchanger 22 connected by the connection pipes 12. more than the number of rooms in As a result, the number of times the flow direction of the refrigerant changes in the second heat exchanger 22 becomes smaller than the number of times the flow direction of the refrigerant changes in the first heat exchanger 21, and the insides of the third header 223 and the fourth header 224 Pressure loss due to collision or friction between the wall surface and the coolant is reduced.

When operated as an evaporator, the number of heat transfer tubes 212 connected to the room of the first heat exchanger 21 connected to the pipe 11c and into which the liquid-containing refrigerant flows <the first heat exchange in which the refrigerant flows out to the connection pipe 12 The number of the first heat transfer pipes 212 connected to the chamber 21 ≤ the number of the second heat transfer pipes 222 connected to the chamber of the second heat exchanger 22 into which the refrigerant flows from the connecting pipe 12 ≤ the number of the second heat transfer pipes 222 connected to the pipe 11d It is the number of the second heat transfer tubes 222 connected to the room of the second heat exchanger 22 through which the vaporized refrigerant flows out.

In addition, since the second heat transfer tubes 222 protrude into the third header 223 and the fourth header 224, pressure loss due to refrigerant flow resistance can be reduced even if the flow expands or contracts.

Unlike the first heat exchanger 21, the second heat exchanger 22 may be configured so that the cross-sectional area of the flow path does not fluctuate throughout the refrigerant path. The first chamber 223a of the third header 223 and the second chamber 224b of the fourth header 224 are the same in size, and the refrigerant flows in and out of the third header 223 and has no folded refrigerant. The second chamber 223b and the first chamber 224a of the fourth header 224 may have the same size. The number of the second heat transfer tubes 222 connected to the first chamber 223a of the third header 223 and the second chamber 224b of the fourth header 224 are the same, and the second chamber 223b of the third header 223 and the fourth header 224 It is desirable that the number of the second heat transfer tubes 222 connected to each of the first chambers 224a is the same. That is, the number of the second heat transfer tubes 222 in which the refrigerant flows from one of the chambers of the third header 223 and the fourth header 224 to the chamber of the opposing fourth header 224 and the third header 223 is the same. Therefore, the second heat exchanger 22 having a short heat transfer tube length can maintain a large flow passage cross-sectional area over the entire length of the heat transfer tube. Note that the quotient obtained by dividing the number of second heat transfer tubes 222 connected to the third header 223 by the number of rooms in the third header 223 may not be an integer. In such a case, the number of the third headers 223 to be connected to each room should be adjusted to an integer by adding or subtracting less than 1 to the quotient, and the difference between the numbers should be 1 or less. . Although the numbers in each room are not exactly the same, they are approximately the same, so the effects described above can be obtained. For example, when the number of second heat transfer tubes 222 connected to the third header 223 is 21 and the number of rooms in the third header 223 is 2, the number of tubes connected to each room is 10 and 11. becomes. In addition, the size of each chamber of the third header 223 may change by about 10% along with this, but even in such a case, the plurality of chambers are of the same size in the present disclosure, and the second heat transfer tubes connected 222 are assumed to be the same.

Refrigerant having a higher degree of dryness than the refrigerant flowing through the first header 213 flows through the third header 223 and the fourth header 224 . By maintaining a large flow cross-sectional area over the entire path of the refrigerant flowing through the second heat exchanger 22, pressure loss in the second heat exchanger 22 when the indoor heat exchanger 10 is operating as an evaporator can be reduced.

The average size of the rooms in the first header 213 (first room 213a to third room 213c) is partitioned so as to be smaller than the average size of the rooms in the third header 223 (first room 223a and second room 223b). ing. That is, during the condenser operation of the indoor heat exchanger 10, the average size of the chambers (first chamber 213a to third chamber 213c) of the first heat exchanger 21 arranged on the downstream side of the refrigerant is the second heat exchange It is partitioned so as to be smaller than the average size of the chambers of the container 22 (the first chamber 223a and the second chamber 223b). As a result, in the indoor heat exchanger 10, the region in which the supercooled refrigerant having a high refrigerant density exists is reduced, and the amount of refrigerant can be reduced.

In the above, an example in which the indoor heat exchanger 10 is composed of the first heat exchanger 21 and the second heat exchanger 22 is shown. It may be composed of one heat exchanger 21 and a second heat exchanger 22 .

Further, the indoor heat exchanger 10 is composed of the first heat exchanger 21 and the second heat exchanger 22, and the outdoor heat exchanger 16 is also composed of the first heat exchanger 21 and the second heat exchanger 22. good too.

The pipe 11c through which the two-phase refrigerant flows when the indoor heat exchanger 10 performs condenser operation is longer than the pipe 11b through which the two-phase refrigerant flows when the outdoor heat exchanger 16 performs condenser operation. Therefore, from the viewpoint of reducing the amount of refrigerant during operation of the condenser, by configuring the indoor heat exchanger 10 with the first heat exchanger 21 and the second heat exchanger 22, the effect of reducing the amount of refrigerant is increased.

According to the air conditioner 200 according to Embodiment 1 described above, the length L1 of the _first heat transfer tube 212 of the first heat exchanger 21 constituting the indoor heat exchanger 10 is equal to that of the second heat exchanger 22 is longer than the length L2 of the _second heat transfer tube 222 . Therefore, when the indoor heat exchanger 10 functions as an evaporator, the second heat exchanger 22 of the second heat exchanger 22 having a length shorter than the length L1 of the _first heat transfer tube 212 of the first heat exchanger 21 A refrigerant having a high degree of dryness flows through the heat pipe 222 . Thereby, the pressure loss is reduced, and the performance of the indoor heat exchanger 10 is enhanced. In addition, when the indoor heat exchanger 10 functions as a condenser, the heat exchange of the first heat exchanger 21 is promoted, so the circulation of refrigerant with a high degree of dryness is promoted. As a result, the average refrigerant density of the first header 213, the second header 214, the third header 223, and the fourth header 224 is reduced, and the refrigerant can be saved.

In addition, the refrigerant pipe through which the refrigerant with high dryness flows when the indoor heat exchanger 10 functions as a condenser is circulated with the refrigerant with high dryness when the outdoor heat exchanger 16 functions as a condenser. Longer than refrigerant piping. Therefore, by configuring the indoor heat exchanger 10 with the first heat exchanger 21 and the second heat exchanger 22, the refrigerant saving effect can be obtained more greatly.

In addition, since the number of rooms (first room 213a to third room 213c) in the first header 213 is greater than the number of rooms (first room 223a, second room 223b) in the third header 223, Pressure loss in the third header 223 is reduced when the heat exchanger 10 functions as an evaporator. Thereby, it is possible to improve the performance of the indoor heat exchanger 10 .

Further, among the plurality of chambers 213a to 213c of the first header 213, the first chamber 213a, which is located downstream in the refrigerant flow direction when the indoor heat exchanger 10 functions as a condenser, is located upstream. It is smaller than the second chamber 213b and the third chamber 213c. For this reason, the refrigerant with low dryness and in a supercooled state is less likely to stay in the first header 213 .

Also, the first chamber 223a and the second chamber 223b of the third header 223 are partitioned to have the same size. Since the partitions are equally sized in this way, when the indoor heat exchanger 10 functions as an evaporator, it is possible to increase the cross-sectional area of the flow path through which the refrigerant with high dryness flows. , pressure loss is reduced, and performance can be improved.

In addition, when a refrigerant having a lower gas density than the R32 refrigerant or the R410A refrigerant is used as the refrigerant, the refrigerant flow velocity per capacity increases, so the performance improvement effect due to the pressure loss reduction is large. Examples of such refrigerants include olefinic refrigerants having double bonds in their molecules such as HFO1234yf and HFP1234ze(E), propane, and DME (dimethyl ether).

Note that the first heat exchanger 21 and the second heat exchanger 22 may be integrally molded as long as the length restrictions of the first heat transfer tube 212 and the second heat transfer tube 222 are secured.

<First modification>
FIG. 7 is a schematic diagram of a first modification of the indoor heat exchanger 10 according to Embodiment 1. FIG.

As shown in FIG. 7, the indoor heat exchanger 10 according to the first modification differs from the configuration in FIG. 2 in connection positions of the

pipes

11c and 11d. In FIG. 2, in the first heat exchanger 21, the pipe 11c is connected to the first header 213 and the connection pipe 12 is connected to the second header 214. As shown in FIG. That is, the pipe 11c and the connection pipe 12 are connected to different headers. 2, the pipe 11d is connected to the fourth header 224 in the second heat exchanger 22, and the connection pipe 12 is connected to the third header 223. As shown in FIG. That is, the pipe 11d and the connection pipe 12 are connected to different headers. 7, in the first heat exchanger 21, the pipe 11c and the connection pipe 12 are connected to the same first header 213. As shown in FIG. Further, in the first modification, in the second heat exchanger 22, the pipe 11d and the connection pipe 12 are connected to the same third header 223. As shown in FIG. Further, in FIG. 7, the space inside the third header 223 is partitioned so that a plurality of rooms (the first room 223a and the second room 223b) have the same size.

In the indoor heat exchanger 10, the second header 214 and the fourth header 224 are positioned farthest apart from each other, and the first header 213 and the third header 223 are positioned closest to each other. Also in the first modified example, the connecting pipes 12 are configured to connect rooms at one end of the adjacent first header 213 and third header 223, as in FIG. Such connection of the horizontal ends of adjacent headers is effective in shortening the connecting pipe 12 . In addition,

pipes

11c and 11d for inflow and outflow of the refrigerant are connected to rooms at the other ends in the horizontal direction of the adjacent first and

third headers

213 and 223, respectively. No piping is connected to the second header 214 and the fourth header 224 . Therefore, this configuration is advantageous in simplifying the routing of the pipes and downsizing the indoor heat exchanger 10, and is also effective in reducing the amount of refrigerant.

Since the connections of the

pipes

11c and 11d and the connecting pipe 12 are different from those in FIG. 2, the number of rooms and the number of partition members 4 in some headers in FIG. 7 are also different from those in FIG. A first header 213 to which the pipe 11c and the connection pipe 12 are connected is divided into four chambers 213a to 213d by three partition members 4. FIG. The number of partition members 4 and the number of rooms of the first header are greater than those of the second header 214 which is not connected to piping. Similarly, the third header 223 to which the pipe 11d and the connection pipe 12 are connected is divided into two

chambers

213a and 213b by one partition member 4. As shown in FIG. The fourth header 224 does not have the partition member 4 and is composed of one room. The number of partition members 4 and the number of rooms of the third header are greater than those of the fourth header 224 which is not connected to piping.

The point that the first heat transfer tube 212 of the first heat exchanger 21 is longer than the second heat transfer tube 222 of the second heat exchanger 22 is the same as in FIG. Also, the number of partition members 4 in the first header 213 is greater than the number of partition members 4 in the third header 223, the number of rooms in the first header 213 is greater than the number of rooms in the third header 223, and the number of rooms in the first header 213 is greater than that in the third header 223. Similarly to FIG. 2, the average size of the rooms in the header 213 is smaller than the average size of the rooms in the third header 223 . For this reason, the first modification can achieve both saving of refrigerant and reduction of pressure loss in the same manner as the configuration of FIG. 2, and the size of the heat exchanger can be reduced.

<Second modification>
FIG. 8 is a schematic diagram of a second modification of the indoor heat exchanger 10 according to Embodiment 1. FIG. As shown in FIG. 8 , the indoor heat exchanger 10 according to the second modification includes a first heat exchanger 21 , a second heat exchanger 22 and a third heat exchanger 23 .

A first header 213 of the first heat exchanger 21 is partitioned into a plurality of chambers 213a to 213c by a plurality of partition members 4, and a second header 214 is partitioned into a plurality of chambers 214a to 214c by a plurality of partition members 4. ing.

The third header 223 of the second heat exchanger 22 is partitioned into a first chamber 223a and a second chamber 223b.

The third heat exchanger 23 is a serpentine heat exchanger in which one third heat transfer tube 6 rotates multiple times.

The third heat transfer pipe 6 of the third heat exchanger 23 has one end 8 connected to the pipe 11 c and the other end 7 connected to the first chamber 213 a of the first header 213 .

The length L3 from one turning position of the _third heat transfer tube 6 to the next turning position is shorter than the length L1 of the _first heat transfer tube 212 of the first heat exchanger 21 . Further, the total length of the pipeline of the third heat transfer tube 6 is longer than the length L1 of the _first heat transfer tube 212 .

In the indoor heat exchanger 10 according to the second modification, when the indoor heat exchanger 10 is in evaporator operation, the refrigerant flows from the pipe 11c into the one end 8 of the third heat transfer tube 6, and the other end 7 of the third heat transfer tube 6 flowing towards The refrigerant then flows from the other end 7 into the first chamber 213 a of the first header 213 .

The refrigerant flows from the first chamber 213a of the first header 213 through the first chamber 214a of the second header 214, the second chamber 213b of the first header 213, and the second chamber 214b of the second header 214 to the first It flows into the third chamber 213 c of the header 213 .

Then, the refrigerant flows from the third chamber 213c of the first header 213, through the third chamber 214c of the second header 214, through the connecting pipe 12, and into the first chamber 223a of the third header 223. After passing through the fourth header 224, the refrigerant reaches the second chamber 223b of the third header 223 and flows out from the pipe 11d.

At this time, the length L3 from one turning position of the third heat transfer tube 6 to the next turning position is shorter than the length L1 of the _first heat transfer tube 212, but the tube of the _third heat transfer tube 6 The total length of the passage is longer than the length L1 of the _first heat transfer tube 212 . A second modification is a configuration in which a third heat exchanger 23 is installed between the pipe 11c and the first chamber 213a of the first header 213 to which the pipe 11c is connected, in the structures of FIGS. can be considered. The third heat exchanger 23 is longer and fewer in number than the first heat transfer tubes 212 connected to the first chamber 213a of the first header 213 chamber, and therefore has a small flow cross-sectional area. Therefore, the density of refrigerant flowing into the second header 214 is reduced, and the average amount of refrigerant in the entire first header 213, second header 214, third header 223, and fourth header 224 can be reduced.

Embodiment 2
FIG. 9 is a schematic diagram showing an indoor unit 202 according to Embodiment 2. FIG. The indoor unit 202 according to Embodiment 2 is an example of the indoor unit 202 of the air conditioner 200 according to Embodiment 1. FIG.

As shown in FIG. 9, in the indoor unit 202 according to Embodiment 2, the height position of the second header 214 of the first heat exchanger 21 is the height position of the fourth header 224 of the second heat exchanger 22. It is arranged so as to be lower in the vertical direction 31 than the . Also, the first header 213 of the first heat exchanger 21 and the third header 223 of the second heat exchanger 22 have the same height. The first heat transfer pipes 212 of the first heat exchanger 21 and the second heat transfer pipes 222 of the second heat exchanger 22 are both oblique with respect to the vertical direction. and the third header 223 are horizontally adjacent to each other, and the second header 214 and the fourth header 224 located at the lower ends thereof are horizontally separated from each other.

That is, in the indoor unit 202 according to Embodiment 2, the lowest portion 41 of the first heat exchanger 21 is located below the lowest portion 42 of the second heat exchanger 22 in the vertical direction 31. .

FIG. 10 is a schematic diagram showing refrigerant flowing through the connecting pipe 12 of the indoor heat exchanger 10 of FIG. FIG. 10 shows how the indoor heat exchanger 10 operates as a condenser. The coolant is a mixture of liquid-phase coolant 61 and gas-phase coolant 62 , which flow through the connecting pipe 12 . The connection pipe 12 in this figure shows a configuration in which the upper surface of the first header 213 and the upper surface of the third header 223 are connected by the U-shaped connection pipe 12 . The connecting pipes 12 may connect the horizontal ends of the first header 213 and the third header 223, that is, the connecting pipes 12 may form a U shape in the depth direction of the paper.

As shown in FIG. 10, during condenser operation of the indoor heat exchanger 10, the refrigerant flows from the second heat exchanger 22 to the first heat exchanger 21 through the connecting pipe 12 in the refrigerant flow direction 30. The refrigerant flowing through the first heat exchanger 21 has a lower degree of dryness than the refrigerant flowing through the second heat exchanger 22 . Refrigerant having dryness between the refrigerant flowing through the first heat exchanger 21 and the refrigerant flowing through the second heat exchanger 22 flows through the connection pipe 12 .

Inertial force 52 acting in the flow direction of the refrigerant and gravity 51 act on the liquid-phase refrigerant 61 moving in the connecting pipe 12 . Since the channel cross-sectional area inside each header is larger than the channel cross-sectional area of each heat transfer tube and the flow velocity is reduced, the inertial force 52 is reduced and the effect of gravity 51 is increased.

When the refrigerant flow rate is large, the inertial force 52 acting on the liquid-phase refrigerant 61 is greater than the gravity force 51, so the liquid-phase refrigerant 61 in the connection pipe 12 moves in the direction from the second heat exchanger 22 to the first heat exchanger 21, that is, , in the coolant flow direction 30 .

During low-capacity operation, the inertial force 52 decreases due to the decrease in the refrigerant flow rate, and the effect of gravity 51 increases.

At this time, if the first heat transfer tube 212 of the first heat exchanger 21 is shorter than the second heat transfer tube 222 of the second heat exchanger 22, the effect of gravity 51 acting in the direction of the second heat exchanger 22 is Increase. Then, the gravity force 51 acting in the direction of the second heat exchanger 22 increases the influence of the inertial force 52 acting on the liquid-phase refrigerant 61 in the connecting pipe 12, and the liquid-phase refrigerant 61 flows in the refrigerant flow direction 30. becomes difficult. As a result, the liquid-phase refrigerant 61 tends to stay in the header and the connecting pipe 12, where the inertial force 52 is particularly small. As a result, the density of the refrigerant in the second heat exchanger 22 increases and the amount of refrigerant increases.

In Embodiment 2, since the first heat transfer tubes 212 of the first heat exchanger 21 are longer than the second heat transfer tubes 222 of the second heat exchanger 22, the The effect of the gravity 51 acting in the direction of the second heat exchanger 22 is greater than the effect of the gravity 51 acting in the direction of the second heat exchanger 22 . As a result, even when the inertial force 52 acting on the liquid-phase refrigerant 61 is reduced during low-capacity operation, the refrigerant can be driven in the refrigerant flow direction 30, thereby suppressing an increase in refrigerant density during low-capacity operation and saving refrigerant. be able to.

In the air conditioner 200 according to Embodiment 2 described above, in the indoor heat exchanger 10, the lowest portion 41 of the first heat exchanger 21 is positioned vertically with respect to the lowest portion 42 of the second heat exchanger 22. It is arranged so as to be positioned below 31 . As a result, when the indoor heat exchanger 10 functions as a condenser, the liquid-phase refrigerant 61 flowing in the first heat exchanger 21 becomes difficult to flow in the refrigerant flow direction 30, and the refrigerant density of the second heat exchanger 22 increases. The increase is reduced, and refrigerant can be saved.

Also, since the second heat transfer tubes 222 are shorter than the first heat transfer tubes 212, the amount of heat exchanged by the second heat exchanger 22 is smaller than when they are the same length. For this reason, the dryness of the second heat exchanger 22 is relatively high, and even if the liquid-phase refrigerant 61 stays in the header and the connecting pipe 12, the amount of the liquid-phase refrigerant 61 is reduced. On the other hand, the dryness of the first heat exchanger 21 is low, and the dryness of the first header 213 and the second header 214 is slightly reduced in some parts. A supercooled state is generally used, and the amount of refrigerant does not change at locations where only the liquid-phase refrigerant 61 flows. As a result, the amount of the liquid-phase refrigerant 61 decreases overall in the heat exchanger having the configuration of the second embodiment.

Embodiment 3
Embodiment 3 refers to the relationship between the indoor heat exchanger 10 and the indoor fan 13b in the indoor unit 202 in the air conditioner 200 of Embodiment 1. As the indoor fan 13b, a horizontal flow fan such as a cross-flow fan is used. A blower with a rotating shaft extending in the direction is adopted. Since the configurations of the air conditioner 200 and the indoor heat exchanger 10 are the same as those of the first embodiment, the description is omitted, and the same or corresponding parts are given the same reference numerals.

FIG. 11 is a perspective view of the indoor unit 202 according to Embodiment 3. FIG. As shown in FIG. 11, the indoor unit 202 is equipped with a cross-flow fan such as a cross-flow fan that operates at low pressure and high air volume as the indoor fan 13b. The indoor fan 13b generates an airflow in the circumferential direction of the rotating shaft 18. As shown in FIG.

In the indoor heat exchanger 10, the first heat transfer tube 212 and the second heat transfer tube 222 are arranged in the circumferential direction of the rotation axis 18, which is the tangential direction of a circle centered on the rotation axis 18 of the indoor fan 13b. The coolant flows in the circumferential direction of the rotating shaft 18 of the .

The first heat exchanger 21 is arranged so that the extending directions of the first header 213 and the second header 214 are parallel to the axial direction of the rotating shaft 18 of the indoor fan 13b. In the second heat exchanger 22, the extension directions of the third header 223 and the fourth header 224 are arranged parallel to the axial direction of the rotation shaft 18 of the indoor fan 13b.

FIG. 12 is a schematic diagram of the AA cross section of the indoor unit 202 in FIG. As shown in FIG. 12, the first heat exchanger 21 and the second heat exchanger 22 are arranged at different positions in the circumferential direction of the rotating shaft 18 of the indoor fan 13b. That is, the first header 213 , the second header 214 , the third header 223 and the fourth header 224 do not overlap in the radial direction of the rotating shaft 18 . The first heat exchanger 21 and the second heat exchanger 22 are arranged in parallel with respect to the airflow flowing into the indoor fan 13b.

By arranging the first heat exchanger 21 and the second heat exchanger 22 in parallel with the airflow in this way, the static pressure of the airflow is reduced and the air volume is improved. As a result, the heat transfer performance is improved, the supercooled region of the refrigerant formed during the operation of the condenser of the indoor heat exchanger 10 is reduced, and the density of the refrigerant is reduced, thereby saving refrigerant.

FIG. 13 is a schematic diagram of the AA cross section of the indoor unit 202 according to the comparative example. As shown in FIG. 13, in the indoor unit 202 according to the comparative example, the first heat exchanger 21 and the second heat exchanger 22 are arranged at the same position in the circumferential direction with respect to the rotating shaft 18 of the indoor fan 13b. It is That is, the first heat exchanger 21 and the second heat exchanger 22 are arranged in series with respect to the airflow of the indoor fan 13b.

If the first heat exchanger 21 and the second heat exchanger 22 are arranged like the indoor unit 202 according to the comparative example, the airflow flowing through the indoor heat exchanger 10 is likely to be obstructed. This is due to the difference in length between the first heat transfer tubes 212 of the first heat exchanger 21 and the second heat transfer tubes 222 of the second heat exchanger 22, resulting in the first header 213, the second header 214, and the This is because the height positions of the third header 223 and the fourth header 224 are different.

As in the indoor unit 202 according to Embodiment 3, the first heat exchanger 21 and the second heat exchanger 22 are arranged in parallel with respect to the airflow, thereby reducing the static pressure of the airflow and increasing the air volume. , the heat transfer performance is improved. As a result, the refrigerant supercooled region formed when the indoor heat exchanger 10 is operated as a condenser can be reduced, and the refrigerant density can be reduced to save refrigerant.

FIG. 14 is a schematic diagram for explaining the relationship between the indoor fan 13b of the indoor unit 202 according to Embodiment 3 and the wind speed. In FIG. 14, the corner portion C of one end of the second header 214 is positioned at 0%, and the corner portion D of the other end of the second header 214 when moved from the corner portion C along the rotation axis direction 33 is positioned at 100%. and 14, the corner E of one end of the fourth header 224 when moved along the first heat transfer tube 212 and the second heat transfer tube 222 in the circumferential direction 34 of the rotating shaft 18 from the corner C is positioned 100 %.

FIG. 15 is a diagram showing the relationship between the position of the indoor fan 13b in the rotation axis direction 33 in FIG. 14 and the wind speed, and the relationship between the position of the rotation shaft 18 of the indoor fan 13b in the circumferential direction 34 and the wind speed. . In FIG. 15, the solid line indicates the relationship between the position of the indoor fan 13b in the rotation axis direction 33 and the wind speed, and the dashed line indicates the relationship between the position of the rotation shaft 18 of the indoor fan 13b in the circumferential direction 34 and the wind speed. ing.

As shown in FIGS. 14 and 15, when the configuration includes the first heat exchanger 21 and the second heat exchanger 22 upstream of the indoor fan 13b, the low-temperature air that has passed through the first heat exchanger 21 and the second The hot air that has passed through the second heat exchanger 22 is mixed with the indoor air blower 13b.

Therefore, when the condenser is in operation, the refrigerant saturation temperature required to blow air at a certain temperature or higher becomes smaller. This increases the performance per air temperature provided to the user.

With the configuration in which the refrigerant flow is provided in a direction parallel to the rotating shaft 18 of the indoor fan 13b, the deviation of the wind speed in the circumferential direction of the rotating shaft 18 of the indoor fan 13b greatly differs. Therefore, the heat exchange capacity of the heat transfer tubes varies greatly, and a region in which the degree of supercooling of the refrigerant becomes large occurs in the operation of the condenser, reducing the refrigerant saving effect.

In contrast, in Embodiment 3, the first heat transfer tube 212 and the second heat transfer tube 222 are arranged in the circumferential direction of the rotation shaft 18 of the indoor fan 13b and in the tangential direction of the circle centered on the rotation shaft 18. there is For this reason, the refrigerant flows in the circumferential direction of the rotation shaft 18 of the indoor fan 13b, where the wind speed deviation in the rotation axis direction 33 is small, and the variation in the heat exchange capacity of the first heat transfer tube 212 and the second heat transfer tube 222 is reduced. . This reduces the difference in the degree of subcooling during condensing operation and saves refrigerant, while reducing the heat load imbalance during condenser operation and evaporator operation, making it possible to improve performance. It is possible to achieve both performance improvement.

The air conditioner 200 according to Embodiment 3 described above employs a cross-flow fan as the indoor fan 13b, and the first heat exchanger 21 and the second heat exchanger 22 are connected to the rotating shaft 18 of the indoor fan 13b. are arranged in parallel in the circumferential direction. As a result, the static pressure of the airflow is reduced and the air volume is improved, so that the heat transfer of the first heat exchanger 21 and the second heat exchanger 22 is improved, and the supercooled region during condenser operation is reduced.

FIG. 16 is a schematic diagram showing the configuration of refrigerant passages of the indoor heat exchanger 10 according to Embodiment 3. As shown in FIG. FIG. 17 is a characteristic diagram showing the effects of refrigerant saving and improvement of heat exchange performance with respect to the refrigerant channel configuration. As shown in FIG. 16, in the indoor heat exchanger 10, the first heat transfer tube 212 connects between the first header 213 and the second header 214, and the second heat transfer tube connects between the third header 223 and the fourth header 224. The heat pipes 222 allow the refrigerant to flow meanderingly between the two opposing headers as indicated by the white arrows. In the example of FIG. 16, the refrigerant flows from the piping 11c of the first heat exchanger 21, the first chamber 213a of the first header 213, the two first heat transfer tubes 212, the first chamber 214a of the second header 214, three the first heat transfer tubes 212, the second chamber 213b of the first header 213, the three first heat transfer tubes 212, the second chamber 214b of the second header 214, the three first heat transfer tubes 212, the first header 213 From the connecting pipe 12 through the third chamber 213c, the five first heat transfer pipes 212, the third chamber 214c of the second header 214, the five first heat transfer pipes 212, and the fourth chamber 213d of the

first header

213, 2 flow to heat exchanger 22; The total number of first heat transfer tubes 212 connecting the first header 213 and the second header 214 is twenty-one. The first heat transfer tubes 212 that connect the rooms of the opposing headers are divided into six groups that flow in different directions as indicated by white arrows. Thus, a plurality of first heat transfer tubes 212 are included in the same group when the chamber of the first header 213 to which one end is connected and the chamber of the second header 214 to which the other end is connected are the same. are grouped to be included in different groups on different occasions. In addition, the fact that the direction in which the refrigerant flows in the heat transfer tubes is turned back in the chamber of the header is called "turning", and the number of times of turning in one heat exchanger is called "turning number". In FIG. 16, the numbers of the first heat transfer tubes 212 divided into groups from the pipe 11c to the connection pipe 12 are n _1,1 , n _1,2 , n _1,3 , n _1,4 , and n ₁ respectively. _{, 5} and n _1,6 . In the first heat transfer tubes 212 of each group, the refrigerant flows in the same direction without turning. In addition, the refrigerant flows in opposite directions in the first heat transfer tubes 212 of adjacent groups. The number of groups in which the flow direction is reversed by turning is the number of times of turning plus one.

Here, the square value of the number of first heat transfer tubes 212 for each group is summed for all groups and divided by the number of first heat transfer tubes 212 in all groups. Let the number of branches be N1. Expressing this in a mathematical formula, N1=Σ(n _1,k ×n _1,k )/Σn _1,k . In the example of FIG. 16, the first heat exchanger 21 has a total of 21 first heat transfer tubes 212, the number of turns is 5, the number of groups is 6, the sum of the squares of the number of groups is 81, The average number of branches N1 is approximately 3.9.

Similarly, in the second heat exchanger 22, the refrigerant is supplied from the connecting pipe 12 to the first chamber 223a of the third header 223, ten second heat transfer tubes 222, the first chamber 224a of the fourth header 224, eleven Through the second heat transfer pipe 222 and the second chamber 223b of the third header 223, the heat flows out from the pipe 11d. The total number of second heat transfer tubes 222 connecting the first header 213 and the second header 214 is 21, like the first heat exchanger 21 . The second heat transfer tubes 222 connecting the chambers of the opposing headers are divided into two groups that flow in different directions as indicated by the hollow arrows. The plurality of second heat transfer tubes 222 are included in the same group when the room of the third header 223 to which one end is connected and the room of the fourth header 224 to which the other end is connected are the same, and are different. divided into groups so that they are included in different groups on occasion. In FIG. 16, the numbers of the second heat transfer tubes 222 divided into groups are indicated as n _2,1 and n _2,2 , respectively. The average branch number N2 of the second heat exchanger 22 is obtained by dividing the sum of the squares of the numbers of the second heat transfer tubes 222 for each group by the number of all groups. Expressing this in a mathematical formula, N2=Σ(n _2,k ×n _2,k )/Σn _2,k . In the example of FIG. 16, for the second heat exchanger 22, the number of turns is one and the number of groups is two for a total of 21 second heat transfer tubes 222. In FIG. The sum of the squares of the numbers in each group is 221, and the average number of branches N2 is about 10.5.

Next, the effect that the first heat transfer tube length L1 of the first heat exchanger 21 and the second heat transfer tube length L2 of the second heat exchanger 22 can reduce the refrigerant and the effect on the performance as a heat exchanger investigated. Let ΔMg be the heat exchanger refrigerant saving effect of the condenser 50% load operation when the first heat transfer tube length L1 and the second heat transfer tube length L2 are equal. Let Gaε be the heat exchanger performance when the evaporator is operated under a 50% load. Then, the product of ΔMg and Gaε is defined as figure of merit FM. A heat exchanger with a large figure of merit FM is superior in terms of refrigerant saving effect and figure of merit.

FIG. 17 is a characteristic diagram showing the figure of merit FM for the refrigerant channel configuration of the heat exchanger 2 according to the third embodiment. The vertical axis in FIG. 17 indicates the figure of merit FM. In the test, the first heat exchanger 21 and the second heat exchanger 22 were arranged around the rotating shaft of the indoor fan 13b, and R32 was used as the refrigerant. FIG. 17 shows the ratio L1/N1 of the first heat transfer tube length L1 to the average number of branches N1 and the ratio L2/N2 of the second heat transfer tube length L2 to the average number N2 of branches, and the figure of merit FM is the ratio (L1/ N1)÷(L2/N2), that is, (L1/N1)×(N2/L2), where L1>L2. As shown in the figure, it was found that the figure of merit FM has the maximum value when (L1/N1)×(N2/L2) is between 2 and 3. Note that FIG. 17 shows the maximum value of the figure of merit FM as 100% of the reference. In the configuration where the number and length of the heat transfer tubes of the first heat exchanger 21 and the second heat exchanger 22 are the same, (L1/N1) × (N2/L2) = 1, but compared to that case, the average branch It shows that the figure of merit FM of 1.5 times or more can be obtained by adjusting the number and length. In addition, even when (L1/N1)×(N2/L2) is in the range of 1.3 to 5.2, it was found that performance of 80% or more of the maximum value was obtained, and the figure of merit FM was greatly improved. It is even better when (L1/N1)×(N2/L2) is between 1.4 and 4.5, and a performance of 90% or more of the maximum value can be obtained. Increasing L1/N1 with respect to L2/N2, that is, increasing L1 or decreasing N1 improves the refrigerant saving effect, but if it is too large, the heat exchange performance decreases. Also, it is considered that when the first heat exchanger 21 and the second heat exchanger 22 have the same configuration and (L1/N1)×(N2/L2) approaches 1, the refrigerant saving effect decreases.

When the refrigerant type changes, depending on the operating refrigerant pressure P and the amount of latent heat change ΔH, the figure of merit FM changes somewhat due to the influence of N1 and N2, but if the ratio of N1 and N2 is the same, the influence is small. For example, even if the refrigerant type is changed from R32 to R410A, or to olefinic refrigerants, propane, dimethyl ether, etc., which are refrigerants with lower gas densities, the relative change in N2 to N1 at which the figure of merit FM peaks is 8 % or less. Therefore, even if the refrigerant type changes, it is expected that the effect of improving the figure of merit FM will be obtained in the range of (L1/N1) × (N2/L2) where the effect was seen with the above refrigerant R32. can.

In addition, even if the temperature of the air that has passed through the first heat exchanger 21 and the temperature of the air that has passed through the second heat exchanger 22 are different, the air is mixed by the indoor fan 13b, and the air is provided indoors. Better performance per applied air temperature.

Embodiment 4
Embodiment 4 refers to the relationship between the indoor heat exchanger 10 in the indoor unit 202 and the indoor fan 13b in the air conditioner 200 of Embodiment 1, and an axial flow fan is adopted as the indoor fan 13b. is doing. Since the configurations of the air conditioner 200 and the indoor heat exchanger 10 are the same as those of the first embodiment, the description is omitted, and the same or corresponding parts are given the same reference numerals.

18 is a perspective view of the indoor unit 202 according to Embodiment 3. FIG. As shown in FIG. 18, the indoor unit 202 is equipped with an axial flow fan such as a propeller fan that operates at low pressure and high air volume as the indoor fan 13b. An air current is generated from the inlet 35 toward the outlet 36 in the direction of the rotating shaft 18 by the indoor blower 13b.

The indoor heat exchanger 10 is arranged so that the extending direction of the first header 213 and the second header 214 of the first heat exchanger 21 is parallel to the direction orthogonal to the rotating shaft 18 of the indoor fan 13b. In addition, the second heat exchanger 22 is arranged such that the extending direction of the third header 223 and the fourth header 224 is parallel to the direction perpendicular to the rotating shaft 18 of the indoor fan 13b. That is, the extending directions of the first header 213, the second header 214, the third header 223, and the fourth header 224 extend in the tangential direction of a circle centered on the rotating shaft 18 of the indoor fan 13b. The first heat exchanger 21 and the second heat exchanger 22 are arranged at positions that do not overlap each other around the rotating shaft 18 when viewed from the axial direction of the rotating shaft 18 . The angular range in which the first heat exchanger 21 is positioned around the rotation axis 18 and the angular range in which the second heat exchanger 22 is positioned around the rotation axis 18 are different.

FIG. 19 is a schematic diagram of the BB cross section of the indoor unit 202 in FIG. In FIG. 19 , straight line F is a straight line connecting second header 214 of first heat exchanger 21 and fourth header 224 of second heat exchanger 22 . The bottom G indicates the height positions of the first heat exchanger 21 and the second heat exchanger 22 in the vertical direction 31 . Further, in FIG. 19, the straight line F is set at 100% height position, and the bottom G is set at 0% height position.

As shown in FIG. 19 , the first heat exchanger 21 and the second heat exchanger 22 are located between the straight line F and the rotation axis 18 in a cross section passing through the rotation axis 18 of the indoor fan 13b and perpendicular to the extending direction. Centering on the intersection 45, they are arranged at different positions in the circumferential direction.

By arranging the first heat exchanger 21 and the second heat exchanger 22 in parallel with respect to the airflow in this way, the static pressure of the airflow is reduced compared to the case of arranging them in series with respect to the airflow. Smaller, better airflow and improved heat transfer. As a result, when the indoor heat exchanger 10 operates as a condenser, the supercooled region of the refrigerant is reduced, the density of the refrigerant is reduced, and the refrigerant can be saved.

FIG. 20 is a schematic diagram showing the wind speed distribution of the airflow flowing through the indoor unit 202 of FIG. In FIG. 20, the vertical axis indicates the height position in the vertical direction 31 from the bottom G to the straight line F in the indoor unit 202, and the horizontal axis indicates the wind speed.

As shown in FIG. 20, if the indoor fan 13b is an axial fan, the difference in wind speed in the vertical direction 31 will increase due to the distance between the indoor fan 13b and the indoor heat exchanger 10.

In the indoor heat exchanger 10, the extension directions of the first header 213, the second header 214, the third header 223, and the fourth header 224 are provided along the tangential direction of a circle centered on the rotation axis 18. ing. One end of the first heat transfer tube 212 of the first heat exchanger 21 and the second heat transfer tube 222 of the second heat exchanger 22 are positioned at the height of the straight line F, and the other end is positioned at the height of the bottom G. is located.

Therefore, there is no difference in air volume around the first heat transfer tubes 212 between the first heat transfer tubes 212 , and there is no difference in air volume around the second heat transfer tubes 222 between the second heat transfer tubes 222 . Therefore, the difference in the amount of heat exchanged between the first heat transfer tubes 212 and between the second heat transfer tubes 222 is reduced, and it is possible to reduce the supercooling region in the condenser operation and improve the performance in the condenser operation or the evaporator operation. As a result, both refrigerant saving and high performance can be achieved.

In the above, an example in which the airflow flows from the suction port 35 to the blowout port 36 is described, but the effect is not affected even if the flow from the suction port 35 to the blowout port 36 is reversed.

The air conditioner 200 according to Embodiment 4 described above employs an axial flow fan as the indoor fan 13b, and the first heat exchanger 21 and the second heat exchanger 22 are arranged in parallel with respect to the air flow. ing. As a result, the static pressure of the airflow is reduced and the air volume is increased, which improves heat transfer and reduces the supercooled region during condenser operation. In addition, variations in heat exchange capacity between the first heat transfer tubes 212 and between the second heat transfer tubes 222 are reduced, so refrigerant can be saved during condenser operation and performance can be improved during evaporator operation.

Embodiment 5
Embodiment 5 refers to the relationship between the indoor heat exchanger 10 and the indoor blower 13b in the indoor unit 202 in the air conditioner 200 of Embodiment 1, and the scroll casing 5 is provided as the indoor blower 13b. A centrifugal blower is used. Since the configurations of the air conditioner 200 and the indoor heat exchanger 10 are the same as those of the first embodiment, the description is omitted, and the same or corresponding parts are given the same reference numerals.

FIG. 21 is a schematic diagram showing a schematic cross section of the indoor unit 202 according to Embodiment 5. FIG. As shown in FIG. 21, the indoor unit 202 includes a centrifugal blower such as a multi-blade blower as the indoor blower 13b, and an indoor blower configured by a scroll casing 5 (hereinafter referred to as a casing) housing the centrifugal blower. 13b is installed. As such a centrifugal blower, there is a sirocco fan or the like. A typical centrifugal fan has a structure in which a plurality of blades are arranged in a cylindrical shape. The casing 5 has a rotation angle position at which the distance between the casing 5 and the blades is the closest in the rotation angle around the rotation axis of the centrifugal fan, and the distance from the blades gradually increases from that position in the rotation direction of the blades. A winding start position 19 is defined as a position in the casing 5 where the distance to the blade is closest. That is, the outer shape of the scroll casing 5 when viewed from the rotation axis direction is closest to the rotation outer circumference of the internal blade at the winding start position 19, and gradually becomes farther from the rotation outer circumference of the blade as it progresses in the rotation direction of the blade. It is a shape. The indoor blower 13b sucks air from the direction of the rotation axis, and the casing 5 has an outlet for blowing air in the tangential direction of the rotation of the blades before making one turn from the winding start position 19 in the rotation direction of the blades. In the following description, viewing the casing 5 in the rotation direction of the blade is viewed in the winding direction 32 . A winding start position 19 is immediately adjacent in the winding direction 32 from the outlet. Therefore, the winding start position 19 is constricted at an acute angle when viewed in the rotation axis direction, and is also called a tongue. In FIG. 21 , position H is the position where the first heat exchanger 21 is closest to the casing 5 . Position I is the position where the second heat exchanger 22 is closest to the casing 5 . FIG. 22 is a schematic cross-sectional view showing an outline of the AA cross section of the indoor unit 202 according to Embodiment 5. As shown in FIG.

In the indoor heat exchanger 10, the extension directions of the first header 213 and the second header 214 of the first heat exchanger 21 are arranged parallel to the axial direction of the rotation shaft 18 of the indoor fan 13b. The extension direction of the third header 223 and the fourth header 224 of the second heat exchanger 22 is arranged parallel to the axial direction of the rotating shaft 18 of the indoor fan 13b. The first heat transfer tube 212 and the second heat transfer tube 222 extend in a direction perpendicular to the rotation axis of the indoor fan 13b.

In the second heat exchanger 22, when viewed in the winding direction 32 of the casing 5, the distance from the winding start position 19 of the casing 5 to the position I is shorter than the distance from the winding start position 19 of the casing 5 to the position H. . That is, the second heat exchanger 22 is arranged at a position close to the winding start position 19 of the casing 5, and the first heat exchanger 21 is arranged at a position far from the winding start position 19 of the casing 5 when viewed in the winding direction 32 of the casing 5. are placed.

In the indoor fan 13b having the casing 5, the airflow is relatively small near the winding start position 19 of the casing 5, and increases with increasing distance. During the condenser operation of the indoor heat exchanger 10, the amount of air flowing through the first heat exchanger 21 increases, so the heat transfer of the first heat exchanger 21 is promoted, and the refrigerant in the first heat exchanger 21 is subcooled. area becomes smaller. As a result, the refrigerant density is reduced, and the refrigerant can be saved.

During the evaporator operation of the indoor heat exchanger 10, the refrigerant pressure in the second heat exchanger 22 is on the low pressure side, so condensed water is generated due to the refrigerant temperature difference from the air temperature and passes through the second heat exchanger 22. When the airflow is large, the condensed water is blown out from the surfaces of the second fins 221 into the interior space. By arranging the second heat exchanger 22 on the upstream side of the airflow near the winding start position 19 of the casing 5, the inertial force that blows off the condensed water from the surface of the second fins 221 is reduced. As a result, the air volume can be increased without degrading the quality of the indoor heat exchanger 10, and the performance of the air conditioner 200 can be improved.

In the air conditioner 200 according to Embodiment 5 described above, the distance from the winding start position 19 of the casing 5 is the distance from the winding start position 19 of the casing 5 to the first heat exchanger 21 . It is arranged so that it is closer than the distance to. Therefore, when the condenser is operated, the air volume of the first heat exchanger 21 increases, so that the supercooled region becomes smaller and the density of the refrigerant is reduced, which makes it possible to save the refrigerant. In addition, since the second heat exchanger 22 is arranged on the upstream side of the airflow during evaporator operation, the inertial force of the airflow that blows off the condensed water into the indoor space is reduced, and the quality of the indoor heat exchanger 10 is reduced. It is possible to increase the air volume without

Also, as shown in FIG. 22, the length of the blower casing 5 in the direction of the rotation axis 18 is shorter than the length of the first heat exchanger 21 in the direction of the rotation axis 18 . The casing 5 is formed with an intake port 5a for sucking air in the direction of the rotating shaft 18 . The first chamber 213a of the second heat exchanger 22, which is the most downstream when operating as a condenser, is located at a position where at least a portion, preferably the entire region, is deviated from the casing 5 in the direction of the rotation axis 18. It is in. Since the first chamber 213a is located at a position where the casing 5 cannot be provided in the rotation circumferential direction of the rotating shaft 18 of the blower, the amount of air passing through the first heat transfer pipes 212 and the first fins 211 connected to the first chamber 213a is small. , the air volume increases compared to the region overlapping the casing 5 in the direction of the rotation axis 18 . Therefore, in the heat exchanger of Embodiment 5, it is possible to promote heat transfer of the liquid refrigerant and achieve both refrigerant saving and high performance. Further, the same effect can be obtained even if the indoor fan 13b is provided with a centrifugal fan such as a multi-blade fan, a scroll casing accommodating the centrifugal fan, and a cross-flow fan in a part thereof.

In addition, the first heat exchanger 21 and the second heat exchanger 22 are arranged at positions that do not overlap each other around the rotation shaft 18 when viewed from the axial direction of the rotation shaft 18 of the centrifugal fan 13b. ing. The angular range in which the first heat exchanger 21 is positioned around the rotation axis 18 and the angular range in which the second heat exchanger 22 is positioned around the rotation axis 18 are different. Therefore, as described in the fourth embodiment, by arranging the first heat exchanger 21 and the second heat exchanger 22 in parallel with respect to the airflow, compared with the case of arranging in series with respect to the airflow As a result, the static pressure of the airflow is reduced, air volume is increased, and heat transfer is improved. As a result, when the indoor heat exchanger 10 operates as a condenser, the supercooled region of the refrigerant is reduced, the density of the refrigerant is reduced, and the refrigerant can be saved.

In addition, since the first heat exchanger 21 and the second heat exchanger 22 are arranged in parallel with respect to the airflow, the static pressure of the airflow is reduced, and the air volume is improved, thereby improving heat transfer. The supercooling zone during operation is reduced.

The present disclosure can be used for an air conditioner equipped with a heat exchanger that functions both as a condenser and as an evaporator.

4 partition member, 5 casing, 6 third heat transfer tube, 7 other end, 8 one end, 10 indoor heat exchanger, 11a piping, 11b piping, 11c piping, 11d piping, 12 connecting piping, 13a outdoor fan, 13b indoor fan, 14 compressor, 15 four-way valve, 16 outdoor heat exchanger, 17 expansion device (decompression device), 18 rotary shaft, 19 casing winding start position, 20 impeller, 21 first heat exchanger, 22 second heat exchanger, 23 Third heat exchanger, 30 Refrigerant flow direction, 31 Vertical direction, 32 Casing winding direction, 33 Rotation axis direction, 35 Suction port, 36 Outlet, 41 Bottom, 42 Bottom, 45 Intersection, 51 Gravity, 52 Inertia power, 61 liquid phase refrigerant, 62 gas phase refrigerant, 71 flat cross section, 200 air conditioner, 201 outdoor unit, 202 indoor unit, 211 first fin, 212 first heat transfer tube, 213 first header, 213a room, 213b Room 213c Room 213d Room 214 Second header 214a Room 214b Room 214c Room 221 Second fin 222 Second heat transfer tube 223 Third header 223a Room 223b Room 224 Fourth header C Corner, D corner, E corner, F straight line, G bottom.

Claims

A heat exchanger in which a compressor, a condenser, a decompression device, and an evaporator are connected by piping to circulate refrigerant, and the function is switched between the evaporator and the condenser by switching the direction of refrigerant flow; and a fan that generates an airflow so that is sent to the heat exchanger,
The heat exchanger is
A plurality of first heat transfer tubes and a first heat transfer tube extending in the horizontal direction and partitioned into a plurality of chambers including a first chamber and a second chamber, to which one end of the plurality of first heat transfer tubes is connected a first heat exchanger having one header and a second header extending horizontally to which the other ends of the plurality of first heat transfer tubes are connected;
a plurality of second heat transfer tubes; a third header extending horizontally to which one ends of the plurality of second heat transfer tubes are connected; and a horizontally extending other end of the plurality of second heat transfer tubes. a second heat exchanger having a connected fourth header;
a connection pipe that connects one of the first header and the second header of the first heat exchanger and the third header of the second heat exchanger;
with
In the operation in which the heat exchanger functions as the evaporator, the refrigerant to be evaporated flows from the pipe into the first chamber of the first header, flows from the first chamber to the second header, The plurality of first heat transfer pipes are connected so as to flow from the second header to the second chamber of the first header, and the refrigerant that has passed through the first heat exchanger passes through the connection pipe to the second heat exchange pipe. The plurality of second heat transfer tubes are connected so that the refrigerant flows from the third header to the fourth header after flowing into the third header of the vessel, and the refrigerant that has passed through the second heat exchanger is compressed into the compression The pipe is connected so as to be sucked into the machine,
In the operation in which the heat exchanger functions as the condenser, the refrigerant to be condensed passes through the second heat exchanger from the pipe, and then passes through the connection pipe to the first header of the first heat exchanger. the piping is connected so that the refrigerant that flows into one of the plurality of chambers or the second header and has passed through the first heat exchanger flows out of the first chamber of the first header;
The air conditioner, wherein the length of the plurality of first heat transfer tubes is longer than the length of the plurality of second heat transfer tubes.
The inner space of the second header and the third header is partitioned into a plurality of rooms, and the connection pipes are connected to either one of the plurality of rooms of the first header or one of the plurality of rooms of the second header, The air conditioner according to claim 1, wherein the third header is connected to any one of the plurality of rooms.
3. The method according to claim 2, wherein the number of rooms inside said first header or said second header connected to said connecting pipes is greater than the number of rooms inside said third header connected to said connecting pipes. Air conditioner.
The air conditioner according to any one of claims 1 to 3, wherein said first chamber of said first header is smaller than said second chamber.
The air conditioner according to any one of claims 1 to 4, wherein the space inside the third header is partitioned so that the plurality of rooms have the same size.
The air conditioner according to any one of claims 1 to 5, wherein the lowest portion of the first heat exchanger is located vertically below the lowest portion of the second heat exchanger. .
said first chamber of said first header is a chamber at one horizontal end of said first header;
The connecting pipes connect any of the plurality of rooms of the first header at the other horizontal end, or any of the plurality of rooms of the second header at the other horizontal end and the third header. The air conditioner according to any one of claims 1 to 6, wherein the air conditioner is connected to the
The plurality of first heat transfer tubes are included in the same group when the chamber of the first header to which one end is connected and the chamber of the second header to which the other end is connected are the same. When divided into groups so that they are included in different groups, the squared value of the number of the first heat transfer tubes for each group is summed in all groups, and the summed value is the first heat transfer tube in all groups. The value obtained by dividing by the number of heat transfer tubes is defined as the average number of branches N1 of the first heat exchanger,
The plurality of second heat transfer tubes are included in the same group when the room of the third header to which one end is connected and the room of the fourth header to which the other end is connected are the same. When divided into groups so that they are included in different groups, the squared value of the number of the second heat transfer tubes in each group is summed in all groups, and the summed value is the second heat transfer tube in all groups. The value obtained by dividing by the number of heat transfer tubes is defined as the average number of branches N2 of the second heat exchanger,
When the length of the first heat transfer tube is L1 and the length of the second heat transfer tube is L2,
The air conditioner according to any one of claims 1 to 7, wherein (L1/N1) x (N2/L2) is in the range of 1.3 to 5.2.
The blower is a blower in which blades rotate around a rotation axis, and the first heat exchanger and the second heat exchanger are arranged around the rotation axis when viewed in the axial direction of the rotation axis. 9. The air conditioner according to any one of claims 1 to 8, arranged in a non-overlapping position.
The blower is an axial blower,
the extension directions of the first header, the second header, the third header, and the fourth header extend in a tangential direction of a circle centered on the rotation axis of the blower;
10. The first heat exchanger and the second heat exchanger according to any one of claims 1 to 9, wherein the first heat exchanger and the second heat exchanger are positioned so as not to overlap when viewed in plan on a plane perpendicular to the rotation axis. air conditioner.
The blower is a centrifugal blower with a scroll casing,
The first heat transfer tube and the second heat transfer tube extend in a direction perpendicular to the rotation axis of the blower,
extending directions of the first header, the second header, the third header, and the fourth header extend in a direction parallel to the axial direction of the rotating shaft;
10. The heat exchanger according to any one of claims 1 to 9, wherein the second heat exchanger is closer to the winding start side of the scroll casing than the first heat exchanger when viewed in the winding direction of the scroll casing on a plane orthogonal to the rotating shaft. The air conditioner according to any one of claims 1 to 3.
The air conditioner according to any one of claims 1 to 11, wherein the first heat exchanger and the second heat exchanger are mounted on an indoor unit.
The air conditioner according to any one of claims 1 to 12, wherein the refrigerant is an olefinic refrigerant, propane, or dimethyl ether, and has a lower gas density than R32 refrigerant or R410A refrigerant. Device.
Composed of at least one compressor, a utilization side heat exchanger, an expansion device, and a heat source side heat exchanger,
at least one of the utilization side heat exchanger and the heat source side heat exchanger,
The air conditioner according to any one of claims 1 to 13, comprising said first heat exchanger and said second heat exchanger.