CN109312971B

CN109312971B - Refrigeration cycle device

Info

Publication number: CN109312971B
Application number: CN201680085743.0A
Authority: CN
Inventors: 中村伸; 石桥晃
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2016-06-24
Filing date: 2016-06-24
Publication date: 2020-11-06
Anticipated expiration: 2036-06-24
Also published as: WO2017221400A1; ES2844591T3; JPWO2017221400A1; EP3477227B1; EP3477227A4; US20190128574A1; CN109312971A; EP3477227A1

Abstract

An outdoor heat exchanger (11) of an air conditioning device (1) is provided with a main heat exchange unit (13) and an auxiliary heat exchange unit (15). When an operation is performed in which the outdoor heat exchanger (11) is operated as an evaporator, refrigerant flows from the auxiliary heat exchanger (15) to the main heat exchanger (13) in the outdoor heat exchanger (11), and flows from the 1 st heat transfer tube (33a) of the auxiliary heat exchanger (15a) to the 2 nd heat transfer tube (33b) of the auxiliary heat exchanger (15b) in the auxiliary heat exchanger (15). When the refrigerant outlet temperature is lower than the freezing point of water, the operation is performed such that the refrigerant inlet temperature of the refrigerant flowing into the auxiliary heat exchange unit (15) is higher than the outside air temperature and the refrigerant outlet temperature of the refrigerant sent out from the auxiliary heat exchange unit (15) is lower than the outside air temperature.

Description

Refrigeration cycle device

Technical Field

The present invention relates to a refrigeration cycle apparatus and an outdoor heat exchanger used for the refrigeration cycle apparatus, and more particularly to a refrigeration cycle apparatus including an outdoor heat exchanger provided with a main heat exchange unit and an auxiliary heat exchange unit, and to such an outdoor heat exchanger.

Background

An outdoor heat exchanger used in an air conditioner, which is an example of a refrigeration cycle apparatus, includes an outdoor heat exchanger in which heat transfer tubes through which a refrigerant flows are arranged so as to penetrate a plurality of plate-shaped fins. Such an outdoor heat exchanger is called a fin-tube type heat exchanger. In such an outdoor heat exchanger, flat tubes having a flat cross-sectional shape with a flat cross-sectional shape are used as heat transfer tubes for efficiently performing heat exchange.

Some outdoor heat exchangers include a main heat exchange unit for condensation and an auxiliary heat exchange unit for supercooling. Usually, the main heat exchange unit is disposed above the auxiliary heat exchange unit. When the refrigeration cycle apparatus is caused to perform a cooling operation, the refrigerant flowing into the outdoor heat exchanger exchanges heat with air and condenses while flowing through the main heat exchange unit, becoming a liquid refrigerant. Then, the liquid refrigerant flows through the auxiliary heat exchange portion, and is further cooled. Patent document 1 discloses an example of a refrigeration cycle apparatus including such an outdoor heat exchanger.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-83419

Disclosure of Invention

Problems to be solved by the invention

However, the air conditioning apparatus including the outdoor heat exchanger has the following problems. When the air conditioner is operated to perform a heating operation, the outdoor heat exchanger operates as an evaporator. When the temperature of the outside air in which the outdoor heat exchanger is installed is close to below the freezing point, the surface temperature of the outdoor heat exchanger is lowered to below the freezing point in order to maintain the heat exchange performance, and frost may adhere to the outdoor heat exchanger.

In particular, when the auxiliary heat exchange unit also operates the air conditioning apparatus as an evaporator, frost may adhere to the auxiliary heat exchange unit. If frost adheres to the outdoor heat exchanger, ventilation resistance increases and heat exchange performance decreases. In order to prevent frost from adhering to the air conditioner, a defrosting operation is performed.

When the defrosting operation is performed in a state where frost adheres to the outdoor heat exchanger, the melted water flows from the upper portion to the lower portion of the outdoor heat exchanger and falls as drain water to the lower portion of the outdoor heat exchanger. In this case, in the heat exchanger using the flat tubes as the heat transfer tubes, the melted water is less likely to fall downward, and the water is likely to accumulate in the auxiliary heat exchange portion located below.

Therefore, the time for performing the defrosting operation to melt the attached frost becomes long, and the power consumption increases. On the other hand, when the heating operation is resumed in a state where frost or water remains, the remaining water is cooled by the refrigerant and frozen, and the outdoor heat exchanger may be damaged.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a refrigeration cycle apparatus including an outdoor heat exchanger that prevents frost from adhering to an auxiliary heat exchange unit, and another object thereof is to provide an outdoor heat exchanger including such an auxiliary heat exchange unit.

Means for solving the problems

The refrigeration cycle apparatus of the present invention is a refrigeration cycle apparatus provided with an outdoor heat exchanger. The outdoor heat exchanger includes a 1 st heat exchange unit and a 2 nd heat exchange unit arranged in line with the 1 st heat exchange unit. The 1 st heat exchange unit includes a plurality of plate-like fins, a 1 st heat transfer tube, a 2 nd heat transfer tube, and a pressure loss mechanism. The 1 st heat transfer pipe is disposed so as to penetrate the plurality of fins. The 2 nd heat transfer pipe is arranged to penetrate the plurality of fins with a distance in a direction intersecting the direction in which the 1 st heat transfer pipe extends. The pressure loss mechanism reduces the pressure of the refrigerant flowing through the 1 st heat exchange unit. When the outdoor heat exchanger is operated as an evaporator, if the temperature of the refrigerant flowing out of the 1 st heat exchange unit is lower than the freezing point of water, the outdoor heat exchanger is operated so that the temperature of the refrigerant flowing into the 1 st heat exchange unit is higher than the temperature of the outside air and the temperature of the refrigerant flowing out of the 1 st heat exchange unit is lower than the temperature of the outside air.

An outdoor heat exchanger of the present invention includes a 1 st heat exchange unit and a 2 nd heat exchange unit arranged in line with the 1 st heat exchange unit. The 1 st heat exchange unit includes a plurality of plate-like fins, a 1 st heat transfer tube, a 2 nd heat transfer tube, and a pressure loss unit. The 1 st heat transfer pipe is disposed so as to penetrate the plurality of fins. The 2 nd heat transfer pipe is arranged to penetrate the plurality of fins with a distance in a direction intersecting the direction in which the 1 st heat transfer pipe extends. The pressure loss portion is interposed between the 1 st heat transfer pipe and the 2 nd heat transfer pipe.

Effects of the invention

According to the refrigeration cycle apparatus of the present invention, when the outdoor heat exchanger is operated as an evaporator, if the temperature of the refrigerant flowing out of the 1 st heat exchange unit is lower than the freezing point of water, the refrigeration cycle apparatus is operated such that the temperature of the refrigerant flowing into the 1 st heat exchange unit is higher than the temperature of the outside air and the temperature of the refrigerant flowing out of the 1 st heat exchange unit is lower than the temperature of the outside air. This can prevent frost from adhering to the 1 st heat exchange unit of the outdoor heat exchanger.

According to the outdoor heat exchanger of the present invention, the pressure loss portion that lowers the pressure of the refrigerant is provided between the 1 st heat transfer tube and the 2 nd heat transfer tube arranged so as to penetrate the plurality of fins, respectively. Thus, during operation in which the outdoor heat exchanger operates as an evaporator, the temperature of the refrigerant is controlled based on the relationship with the temperature of the air, and frost can be prevented from adhering to the 1 st heat exchange portion of the outdoor heat exchanger.

Drawings

Fig. 1 is a diagram illustrating an example of a refrigerant circuit of an air conditioning apparatus according to an embodiment.

Fig. 2 is a perspective view showing the outdoor heat exchanger according to this embodiment.

Fig. 3 is a cross-sectional view showing an example of a refrigerant passage of the heat transfer pipe in the embodiment.

Fig. 4 is a cross-sectional view showing another example of the refrigerant passage of the heat transfer pipe in the embodiment.

Fig. 5 is a diagram showing the flow of the refrigerant in the outdoor heat exchanger when the operation is performed in which the outdoor heat exchanger operates as a condenser or when the operation is performed in which the outdoor heat exchanger operates as an evaporator in this embodiment.

Fig. 6 is a perspective view showing the flow of the refrigerant in the outdoor heat exchanger when the outdoor heat exchanger is operated as a condenser in this embodiment.

Fig. 7 is a perspective view showing the flow of the refrigerant in the outdoor heat exchanger in the case where the operation is performed in which the outdoor heat exchanger operates as an evaporator in this embodiment.

Fig. 8 is a diagram for explaining a relationship between the temperature of the refrigerant flowing through the auxiliary heat exchange portion of the outdoor heat exchanger and the temperature of the air in the case where the operation in which the outdoor heat exchanger operates as an evaporator is performed in the air conditioning apparatus according to comparative example 1.

Fig. 9 is a diagram for explaining a relationship between the temperature of the refrigerant flowing through the auxiliary heat exchange portion of the outdoor heat exchanger and the temperature of the air in the case where the operation in which the outdoor heat exchanger operates as an evaporator is performed in the air conditioning apparatus according to comparative example 2.

Fig. 10 is a diagram for explaining a relationship between the temperature of the refrigerant flowing through the auxiliary heat exchange portion of the outdoor heat exchanger and the temperature of the air in the case where the operation is performed in which the outdoor heat exchanger operates as an evaporator in this embodiment.

Fig. 11 is a diagram showing the flow of the refrigerant in the outdoor heat exchanger when the outdoor heat exchanger is operated as the evaporator in the air conditioning apparatus according to comparative example 3.

Fig. 12 is a diagram for explaining a relationship between the temperature of the refrigerant flowing through the auxiliary heat exchange portion of the outdoor heat exchanger and the temperature of the air in the case where the operation in which the outdoor heat exchanger operates as an evaporator is performed in the air conditioning apparatus according to comparative example 3.

Fig. 13 is a diagram for explaining a relationship between the temperature of the refrigerant flowing through the auxiliary heat exchange portion of the outdoor heat exchanger and the temperature of the air in the case where the outdoor heat exchanger is operated as an evaporator in the air conditioning apparatus to which the heat transfer pipe is applied as the pressure loss portion in this embodiment.

Fig. 14 is a side view schematically showing an auxiliary heat exchange unit to which the throttle device of example 1 as a pressure loss unit is attached in this embodiment.

Fig. 15 is a side view schematically showing an auxiliary heat exchange portion to which a throttling device of example 2 as a pressure loss portion is attached in this embodiment.

Fig. 16 is a perspective view schematically showing an auxiliary heat exchange portion to which an inter-row header of example 3 as a pressure loss portion is attached in this embodiment.

Fig. 17 is a sectional view of the section line XVII-XVII shown in fig. 16 in this embodiment.

Fig. 18 is a sectional view of section line XVIII-XVIII shown in fig. 16 in this embodiment.

Fig. 19 is a sectional view of section line XIX-XIX shown in fig. 16 in this embodiment.

Fig. 20 is a perspective view schematically showing an auxiliary heat exchange portion to which a header of example 4 as a pressure loss portion is attached in this embodiment.

Fig. 21 is a perspective view schematically showing an auxiliary heat exchange unit to which a U-shaped pipe as a 5 th example of a pressure loss unit is attached in this embodiment.

Detailed Description

Embodiment mode 1

First, the overall configuration (refrigerant circuit) of an air conditioner, which is an example of a refrigeration cycle device, will be described. As shown in fig. 1, the air conditioner 1 includes a compressor 3, an indoor heat exchanger 5, an indoor fan 7, a throttle device 9, an outdoor heat exchanger 11, an outdoor fan 21, a four-way valve 23, and a controller 51. The compressor 3, the indoor heat exchanger 5, the expansion device 9, the outdoor heat exchanger 11, and the four-way valve 23 are connected by refrigerant pipes.

The air conditioner 1 is provided with two

temperature sensors

53 and 55 for detecting the temperature of the refrigerant in the outdoor heat exchanger 11, and a temperature sensor 57 for detecting the temperature of the outside air. The

temperature sensors

53, 55, and 57 are electrically connected to the control unit 51. As will be described later, in the air conditioning apparatus 1, when the outdoor heat exchanger 11 is operated as an evaporator, the control unit 51 controls the temperature of the refrigerant so as to prevent frost from adhering to the outdoor heat exchanger 11, based on the relationship with the temperature of the outside air (air).

Next, the outdoor heat exchanger 11 will be described. As shown in fig. 2, the outdoor heat exchanger 11 includes a main heat exchange unit 13 and an auxiliary heat exchange unit 15. The main heat exchange unit 13 is disposed above the auxiliary heat exchange unit 15. In the auxiliary heat exchanger 15, a plurality of 1 st heat transfer tubes 33a and a plurality of 2 nd heat transfer tubes 33b are arranged so as to penetrate through a plurality of plate-like fins 31 arranged at intervals.

Flat tubes 33 having a flat cross-sectional shape with a major diameter and a minor diameter are used as the 1 st heat transfer tube 33a and the 2 nd heat transfer tube 33 b. Fig. 3 shows a flat tube 33 having one refrigerant passage 35 formed therein as an example of the flat tube. Fig. 4 shows a flat tube 33 having a plurality of refrigerant passages 35 formed therein as another example of the flat tube. The heat transfer tubes 1 and 2 are not limited to flat tubes, and may be, for example, heat transfer tubes having a circular or elliptical cross-sectional shape.

The 1 st heat transfer tubes 33a are arranged at a distance from each other in the short diameter direction. The 1 st heat transfer tubes 33a are arranged in the 1 st row. Column 1 is an auxiliary heat exchange portion 15 a. The plurality of 2 nd heat transfer tubes 33b are arranged at a distance from each other in the short diameter direction. The plurality of 2 nd heat transfer tubes 33b are arranged in the 2 nd row. Column 2 is an auxiliary heat exchange portion 15 b. As will be described later, when the air conditioner is operated, the auxiliary heat exchange portion 15a (upwind row) is located on the upwind side, and the auxiliary heat exchange portion 15b (downwind row) is located on the downwind side.

One end (1 st end) of each of the plurality of 1 st heat transfer pipes 33a is connected to the distributor 25. The distributor 25 of the auxiliary heat exchange portion 15 is connected to the throttle device 9 (see fig. 5). A temperature sensor 53 for detecting the temperature of the refrigerant is provided in a portion of the refrigerant pipe near the distributor 25. The other ends (No. 2 end portions) of the plurality of 1 st heat transfer tubes 33a and the other ends (No. 3 end portions) of the plurality of 2 nd heat transfer tubes 33b are connected to each other via a pressure loss portion 17 (pressure loss mechanism) that causes pressure loss of the refrigerant. The specific structure of the pressure loss section 17 will be described later.

One end (4 th end) of each of the plurality of 2 nd heat transfer tubes 33b is connected to the main heat exchange portion 13. A temperature sensor 55 for detecting the temperature of the refrigerant is provided in a portion of the refrigerant pipe 37 connected to one end of the 2 nd heat transfer pipe 33 b. In fig. 2, a case is representatively shown in which the temperature sensor 55 is provided in the refrigerant pipe connected to one end of the 2 nd heat transfer pipe 33b disposed at the lowermost position, but the temperature sensor may be provided in a portion of each of the refrigerant pipes connected to one end of the plurality of 2 nd heat transfer pipes 33 b.

In the main heat exchange portion 13, a plurality of 3 rd heat transfer tubes 33c and a plurality of 4 th heat transfer tubes 33d are arranged so as to penetrate through a plurality of plate-like fins 31 arranged at intervals from each other. The flat tubes 33 are used as the 3 rd heat transfer tubes 33c and the 4 th heat transfer tubes 33d in the same manner as the 1 st heat transfer tubes 33a and the 2 nd heat transfer tubes 33 b. In fig. 2, for the sake of simplicity of the drawing, the 3 rd heat transfer pipe 33c and the 4 th heat transfer pipe 33d of one system are shown.

The 3 rd heat transfer tubes 33c are arranged at a distance from each other in the short diameter direction. The plurality of 3 rd heat transfer tubes 33c are arranged in the 1 st row (windward row). Column 1 becomes the main heat exchange portion 13 a. The plurality of 4 th heat transfer tubes 33d are arranged at a distance from each other in the short diameter direction. The plurality of 4 th heat transfer tubes 33d are arranged in the 2 nd row (downwind row). Column 2 becomes the main heat exchange portion 13 b.

One end of each of the plurality of 4 th heat transfer pipes 33d is connected to one end of each of the plurality of 2 nd heat transfer pipes 33b via the distributor 29. The other ends of the plurality of 4 th heat transfer pipes 33d are connected to the corresponding other ends of the plurality of 3 rd heat transfer pipes 33 c. One end of each of the plurality of 3 rd heat transfer tubes 33c is connected to the header 27. The header 27 is connected to the four-way valve 23 (see fig. 5). The outdoor heat exchanger 11 of the air conditioner 1 is configured as described above.

Next, as the operation (flow of the refrigerant) of the air conditioning apparatus 1 described above, first, an operation (cooling operation) in which the outdoor heat exchanger 11 operates as a condenser will be described.

As shown in fig. 5, by driving the compressor 3, the refrigerant in a high-temperature and high-pressure gas state is discharged from the compressor 3. Hereinafter, the refrigerant flows according to the dotted arrow. The discharged high-temperature high-pressure gas refrigerant (single-phase) flows into the outdoor heat exchanger 11 via the four-way valve 23. In the outdoor heat exchanger 11, heat is exchanged between the refrigerant flowing in and the air supplied by the outdoor fan 21, and the high-temperature and high-pressure gas refrigerant is condensed into a high-pressure liquid refrigerant (single phase).

The high-pressure liquid refrigerant sent from the outdoor heat exchanger 11 passes through the expansion device 9, and becomes a refrigerant in a two-phase state of a low-pressure gas refrigerant and a liquid refrigerant. The refrigerant in the two-phase state flows into the indoor heat exchanger 5. In the indoor heat exchanger 5, heat exchange is performed between the refrigerant in the two-phase state that flows in and the air supplied by the indoor fan 7, and the liquid refrigerant evaporates in the refrigerant in the two-phase state to become a low-pressure gas refrigerant (single phase). By this heat exchange, the inside of the chamber is cooled. The low-pressure gas refrigerant sent from the indoor heat exchanger 5 flows into the compressor 3 through the four-way valve 23, is compressed into a high-temperature high-pressure gas refrigerant, and is discharged from the compressor 3 again. This cycle is repeated below.

Here, the flow of the refrigerant in the outdoor heat exchanger 11 when the outdoor heat exchanger 11 is operated as a condenser will be described. As shown in fig. 6, in the outdoor heat exchanger 11, the refrigerant first flows through the main heat exchange portion 13, and then flows through the auxiliary heat exchange portion 15. Further, the outdoor fan 21 (see fig. 1) causes air to flow as indicated by arrows from the auxiliary heat exchanger 15a and the main heat exchanger 13a in the 1 st row (windward row) toward the auxiliary heat exchanger 15b and the main heat exchanger 13b in the 2 nd row (leeward row).

The refrigerant sent from the compressor 3 flows into the header 27, and flows through the header 27 in the 3 rd heat transfer pipe 33c of the main heat exchange portion 13a in the direction indicated by the arrow. The refrigerant flowing through the 3 rd heat transfer pipe 33c then flows through the 4 th heat transfer pipe 33d of the main heat exchanger 13b in the direction indicated by the arrow, and flows into the distributor 29.

The refrigerant flowing into the distributor 29 then flows through the 2 nd heat transfer tubes 33b of the auxiliary heat exchange portion 15b in the direction indicated by the arrow. The refrigerant flowing through the 2 nd heat transfer tubes 33b then flows through the 1 st heat transfer tubes 33a of the auxiliary heat exchanger portion 15a in the direction indicated by the arrow. The refrigerant flowing through the 1 st heat transfer tubes 33a is sent out of the outdoor heat exchanger 11.

Next, an operation (heating operation) in which the outdoor heat exchanger 11 operates as an evaporator will be described. As shown in fig. 5, by driving the compressor 3, the refrigerant in a high-temperature and high-pressure gas state is discharged from the compressor 3. Hereinafter, the refrigerant flows as indicated by solid arrows.

The discharged high-temperature high-pressure gas refrigerant (single-phase) flows into the indoor heat exchanger 5 via the four-way valve 23. In the indoor heat exchanger 5, heat exchange is performed between the gas refrigerant flowing in and the air supplied by the indoor fan 7, and the high-temperature and high-pressure gas refrigerant is condensed into a high-pressure liquid refrigerant (single phase). By this heat exchange, the room is heated. The high-pressure liquid refrigerant sent from the indoor heat exchanger 5 passes through the expansion device 9, and becomes a refrigerant in a two-phase state of a low-pressure gas refrigerant and a liquid refrigerant.

The two-phase refrigerant flows into the outdoor heat exchanger 11. In the outdoor heat exchanger 11, heat exchange is performed between the refrigerant in the two-phase state that flows in and the air supplied by the outdoor fan 21, and the liquid refrigerant in the two-phase state is evaporated to become a low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant sent from the outdoor heat exchanger 11 flows into the compressor 3 via the four-way valve 23, is compressed into a high-temperature high-pressure gas refrigerant, and is discharged from the compressor 3 again. This cycle is repeated below.

Here, the flow of the refrigerant in the outdoor heat exchanger 11 when the outdoor heat exchanger 11 is operated as an evaporator will be described. As shown in fig. 7, in the outdoor heat exchanger 11, the refrigerant first flows through the auxiliary heat exchange unit 15 and then flows through the main heat exchange unit 13. Further, the outdoor fan 21 (see fig. 1) causes air to flow as indicated by arrows from the auxiliary heat exchanger 15a and the main heat exchanger 13a in the 1 st row (windward row) toward the auxiliary heat exchanger 15b and the main heat exchanger 13b in the 2 nd row (leeward row).

The refrigerant sent from the expansion device 9 flows into the distributor 25 of the auxiliary heat exchanger 15, passes through the distributor 25, and flows through the 1 st heat transfer pipe 33a of the auxiliary heat exchanger 15a in the direction indicated by the arrow. The refrigerant flowing through the 1 st heat transfer tubes 33a then flows through the 2 nd heat transfer tubes 33b of the auxiliary heat exchanger portion 15b in the direction indicated by the arrow.

The refrigerant flowing through the 2 nd heat transfer tubes 33b then flows into the distributor 29 of the main heat exchanger 13. The refrigerant flowing into the distributor 29 then flows in the 4 th heat transfer pipe 33d of the main heat exchange portion 13b in the direction indicated by the arrow. The refrigerant flowing through the 4 th heat transfer pipe 33d then flows in the 3 rd heat transfer pipe 33c of the main heat exchange portion 13a in the direction indicated by the arrow. The refrigerant flowing through the 3 rd heat transfer tubes 33c flows into the header 27, passes through the header 27, and is sent out of the outdoor heat exchanger 11.

In the outdoor heat exchanger 11 of the air-conditioning apparatus 1 described above, the temperature of the refrigerant flowing into the auxiliary heat exchange portion 15 (refrigerant inlet temperature), the temperature of the refrigerant sent out from the auxiliary heat exchange portion 15 (refrigerant outlet temperature), and the temperature of the outside air are detected, and the air-conditioning apparatus 1 is operated so that the temperature of the refrigerant and the temperature of the outside air have a predetermined temperature relationship, whereby frost can be prevented from adhering to the auxiliary heat exchange portion 15. This aspect is explained.

First, a general viewpoint relating to adhesion of frost to an outdoor heat exchanger will be described. As an example of the conditions under which frost adheres to the outdoor heat exchanger, a case where the air dry bulb temperature is 2 ℃ and the air wet bulb temperature is 1 ℃ will be described. Under these conditions, the outdoor heat exchanger functions as an evaporator because the dew point temperature of air is about-0.4 ℃. If the air dry bulb temperature is lower than the dew point temperature, moisture condenses in the outdoor heat exchanger. At this time, the air dry bulb temperature is below the freezing point, and thus condensed moisture adheres as frost. Thus, in the outdoor heat exchanger, the ventilation resistance is increased, and the air volume passing through the outdoor heat exchanger is reduced, thereby reducing the heat exchange performance.

Here, if it is desired to ensure the air conditioning capacity of the indoor heat exchanger, it is necessary to make the temperature difference between the temperature of the refrigerant flowing through the outdoor heat exchanger and the temperature of the air larger. Therefore, the temperature of the refrigerant flowing through the outdoor heat exchanger is lowered, and frost further adheres to the outdoor heat exchanger. When frost adheres to the outdoor heat exchanger, a normal operation is performed after a defrosting operation for melting the adhered frost is performed to secure an air conditioning capacity. When the temperature of the outside air is low, the operation is generally repeated.

Next, as an example of the case where the temperature of the outside air is higher than the above-described conditions, a case where the air dry bulb temperature is 5 ℃ and the air wet bulb temperature is 4 ℃ will be described. Under this condition, the dew point temperature of the air is about 2.8 ℃, and when the air dry bulb temperature is lower than the dew point temperature due to heat exchange with the refrigerant, moisture in the air condenses and adheres to the outdoor heat exchanger as water droplets. At this time, the air passing through the outdoor heat exchanger is intended to flow to the leeward side of the outdoor heat exchanger at a temperature lower than the dew point temperature. Therefore, in the case where the refrigerant temperature is lower than the freezing point of water (e.g., 0 ℃), it is also possible for the air dry bulb temperature and the dew point temperature to reach temperatures close to the refrigerant temperature. Thus, when the dew point temperature is lower than the freezing point of water (for example, 0 ℃), frost may adhere to the outdoor heat exchanger.

Next, the adhesion of frost to the auxiliary heat exchange portion of the outdoor heat exchanger is specifically described. Here, as an example of the operation conditions, the air dry bulb temperature was set to 2 ℃, the air wet bulb temperature was set to 1 ℃, and the dew point temperature was set to-0.4 ℃.

First, as the outdoor heat exchanger 11 of the air conditioner of the comparative example, a case will be described in which both the main heat exchange unit 13 and the auxiliary heat exchange unit 15 are used as evaporators when the outdoor heat exchanger 11 is operated as an evaporator (comparative example 1). Fig. 8 shows a graph (broken line) showing a transition of the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15 with respect to the flow direction of the refrigerant, a graph (solid line) showing a transition of the temperature of the air dry bulb with respect to the flow direction of the air, and a graph (dotted line) showing a transition of the dew point temperature with respect to the flow direction of the air.

This operation condition is a condition in which the refrigerant inlet temperature (Tref-in) flowing into the auxiliary heat exchange portion 15 is lower than the outside air temperature (air inlet temperature (Tair-in)). In this case, the air dry bulb temperature immediately reaches a temperature approximately the same as the dew point temperature. The dew point temperature is lower than the freezing point of water (e.g., 0 deg.c), and thus frost adheres to most of the outdoor heat exchanger 11 including the auxiliary heat exchange portion 15.

In the case of performing a defrosting operation for removing frost adhering to the outdoor heat exchanger 11, water (drain water) in which the frost is melted flows toward the lower portion of the outdoor heat exchanger 11 by gravity and is discharged from the outdoor heat exchanger 11. However, in the outdoor heat exchanger 11 using the flat tubes 33 as the heat transfer tubes, the velocity of the drain water flowing down is lowered, and the state where the drain water flows down from above to the auxiliary heat exchange portion 15 disposed below the main heat exchange portion 13 continues. Therefore, additional heat is sometimes required for defrosting of the auxiliary heat exchange portion 15. In addition, the defrosting operation may take time.

The defrosting operation is generally performed in the same operation mode as the operation in which the outdoor heat exchanger operates as a condenser, the direction of the refrigerant flow is opposite to the direction of the refrigerant flow in the operation in which the outdoor heat exchanger 11 operates as an evaporator, and the refrigerant flows through the main heat exchange unit 13 and then flows through the auxiliary heat exchange unit 15 (see fig. 6). The auxiliary heat exchange portion 15 is disposed below the main heat exchange portion 13. Therefore, the heat of the refrigerant is absorbed in the main heat exchange portion 13 on the upstream side of the flow of the refrigerant, and the defrosting capability of the adhering frost is lowered in the auxiliary heat exchange portion 15 on the downstream side, and the defrosting time may be increased. In this way, the comfortable state may not be maintained, for example, the temperature in the room may gradually decrease.

Further, when the defrosting operation is ended with frost remaining and the operation in which the outdoor heat exchanger 11 operates as an evaporator is resumed, the frost may grow further and damage the auxiliary heat exchanger 15 or the like, and for example, damage of the heat transfer tubes may be expected to progress to cause a serious problem such as leakage of the refrigerant.

Next, a case will be described in which the main heat exchange unit 13 is used as an evaporator and the auxiliary heat exchange unit 15 is used as a condenser when the outdoor heat exchanger 11 of another air conditioner of a comparative example is operated as an evaporator (comparative example 2). Fig. 9 shows a graph (broken line) showing a transition of the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15 with respect to the flow direction of the refrigerant, a graph (solid line) showing a transition of the temperature of the air dry bulb with respect to the flow direction of the air, and a graph (dotted line) showing a transition of the dew point temperature with respect to the flow direction of the air.

This operation condition is a condition in which the refrigerant outlet temperature (Tref-out) sent from the auxiliary heat exchange portion 15 is higher than the outside air temperature (air inlet temperature (Tair-in)). In this case, frost does not adhere to the auxiliary heat exchange portion 15, and the auxiliary heat exchange portion 15 is not damaged, thereby ensuring reliability as the auxiliary heat exchange portion 15.

However, in the case of this operating condition, since the refrigerant changes in the direction of liquefaction in the auxiliary heat exchange portion 15 used as a condenser, the load of heat exchange in the main heat exchange portion 13 increases in order to evaporate the liquefied refrigerant in the main heat exchange portion 13 used as an evaporator. Therefore, the heat exchange performance is greatly reduced.

In the outdoor heat exchanger 11 of the air-conditioning apparatus 1 according to the embodiment, the main heat exchanger 13 is used as an evaporator and the auxiliary heat exchanger 15 is used as a condenser and an evaporator, respectively, in comparison with comparative examples 1 and 2. Fig. 10 shows a graph (broken line) showing a transition of the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15 with respect to the flow direction of the refrigerant, a graph (solid line) showing a transition of the temperature of the air dry bulb with respect to the flow direction of the air, and a graph (dotted line) showing a transition of the dew point temperature with respect to the flow direction of the air.

The operation of the outdoor heat exchanger 11 as an evaporator is as follows: when the refrigerant outlet temperature (Tref-out) is lower than the freezing point of water (e.g., 0 ℃), the refrigerant inlet temperature (Tref-in) flowing into the auxiliary heat exchange portion 15 is higher than the outside air temperature (air inlet temperature (Tair-in)), and the refrigerant outlet temperature (Tref-out) sent from the auxiliary heat exchange portion 15 is lower than the outside air temperature (air inlet temperature (Tair-in)).

Since the refrigerant flowing through the auxiliary heat exchange portion 15 is a two-phase refrigerant of a liquid refrigerant and a gas refrigerant, adjusting the pressure loss of the refrigerant in the auxiliary heat exchange portion 15 means the same as adjusting the refrigerant temperature. In the auxiliary heat exchange unit 15, the pressure loss unit 17 is provided between the auxiliary heat exchange unit 15a located in the 1 st row and the auxiliary heat exchange unit 15b located in the 2 nd row, so that the auxiliary heat exchange unit 15a functions as a condenser and the auxiliary heat exchange unit 15b functions as an evaporator.

Since the auxiliary heat exchange portion 15a located in the upwind row functions as a condenser, the temperature of the air rises, and even if the auxiliary heat exchange portion 15b located in the downwind row functions as an evaporator, the temperature of the air is less likely to fall below the dew point temperature. This reduces the temperature of the refrigerant to function as an evaporator in the entire auxiliary heat exchange portion 15, and prevents frost from adhering to the auxiliary heat exchange portion 15. In order to reliably prevent frost from adhering to the auxiliary heat exchange portion 15, the operation may be performed such that the refrigerant outlet temperature (Tref-out) sent from the auxiliary heat exchange portion 15 is higher than the dew point temperature.

In the outdoor heat exchanger 11 of the air-conditioning apparatus 1 of the above-described embodiment, the refrigerant flows through the auxiliary heat exchange portion 15a located on the upstream side and then flows through the auxiliary heat exchange portion 15b located on the downstream side. That is, the refrigerant flows from the windward side to the leeward side in the same manner as the flow of air, and such a flow of the refrigerant is called a parallel flow. The case where the refrigerant flows from the leeward side to the windward side with respect to the parallel flow is referred to as a counter flow.

Here, a case will be described in which, during operation in which the outdoor heat exchanger 11 operates as an evaporator, the refrigerant flows in a counter-current flow to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11 (comparative example 3). As shown in fig. 11, in the outdoor heat exchanger 11, the refrigerant first flows through the auxiliary heat exchange unit 15 and then flows through the main heat exchange unit 13. At this time, in the auxiliary heat exchanger 15, the heat transfer tubes 33b of the auxiliary heat exchanger 15b flow in the direction indicated by the arrow first. The refrigerant flowing through the 2 nd heat transfer tubes 33b then flows in the 1 st heat transfer tubes 33a of the auxiliary heat exchanger portion 15a in the direction indicated by the arrow. The refrigerant flowing through the auxiliary heat exchanger 15a flows through the main heat exchanger 13 and is then sent out from the outdoor heat exchanger 11, as in the case shown in fig. 7.

Fig. 12 shows a graph (broken line) showing a transition of the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15 with respect to the flow direction of the refrigerant, a graph (solid line) showing a transition of the temperature of the air dry bulb with respect to the flow direction of the air, and a graph (dotted line) showing a transition of the dew point temperature with respect to the flow direction of the air, in the case where the flow of the refrigerant is a counter flow.

In this case, even if the pressure loss section 17 for reducing the pressure of the refrigerant is interposed, the temperature of the refrigerant flowing through the auxiliary heat exchange section 15a located on the upstream side is lower than the temperature of the refrigerant flowing through the auxiliary heat exchange section 15b located on the downstream side. At this time, if the temperature of the air is lower than the dew point temperature, frost may adhere to the auxiliary heat exchange portion 15 a.

Here, when the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15a located on the upwind side is made higher than the outside air temperature (air inlet temperature (Tair-in)), the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15b located on the downwind side is also made higher than the outside air temperature (air inlet temperature (Tair-in)). Therefore, the entire auxiliary heat exchange unit 15 functions as a condenser, and as described with reference to fig. 9, the heat exchange performance is degraded. Therefore, in order to prevent frost from adhering to the auxiliary heat exchange portion 15 in the operation in which the outdoor heat exchanger 11 operates as an evaporator, it is preferable to operate the refrigerant as a parallel flow along the flow of air.

(modification of pressure loss section (pressure loss mechanism))

(example 1)

The case where the pressure loss section 17 is interposed between the auxiliary heat exchange section 15a and the auxiliary heat exchange section 15b in the outdoor heat exchanger 11 of the air-conditioning apparatus 1 described above is described. The pressure loss portion may be, for example, friction loss in the heat transfer tubes such as the 1 st heat transfer tube 33a and the 2 nd heat transfer tube 33 b.

Fig. 13 shows a graph (broken line) showing a transition of the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15 with respect to the flow direction of the refrigerant, a graph (solid line) showing a transition of the air dry bulb temperature with respect to the flow direction of the air, and a graph (dotted line) showing a transition of the dew point temperature with respect to the flow direction of the air in the operation in which the outdoor heat exchanger 11 operates as an evaporator.

As shown in fig. 13, as the refrigerant flows through the heat transfer tubes (the 1 st heat transfer tube 33a and the 2 nd heat transfer tube 33b), the temperature of the refrigerant gradually decreases due to friction loss in the heat transfer tubes. The friction loss in the heat transfer pipe is determined by the flow velocity of the refrigerant, the shape of the heat transfer pipe inside the pipe, and the length of the heat transfer pipe. Therefore, the circulation amount of the refrigerant in the air-conditioning apparatus, the size of the heat transfer tubes in the outdoor heat exchanger, the number of passages of the heat transfer tubes, and the like are set to predetermined values based on the design, and the outdoor heat exchanger 11 is operated as an evaporator under the condition that the temperature of the refrigerant has a predetermined temperature relationship, whereby frost can be prevented from adhering to the auxiliary heat exchange portion 15.

That is, when the refrigerant outlet temperature (Tref-out) is lower than the freezing point of water (e.g., 0 ℃), the operation is performed such that the refrigerant inlet temperature (Tref-in) is higher than the outside air temperature (air inlet temperature (Tair-in)) and the refrigerant outlet temperature (Tref-out) is lower than the outside air temperature (air inlet temperature (Tair-in)), thereby preventing frost from adhering to the auxiliary heat exchange portion 15. Further, by operating the auxiliary heat exchange unit 15 so that the refrigerant outlet temperature (Tref-out) is higher than the dew point temperature, frost can be reliably prevented from adhering to the auxiliary heat exchange unit 15.

(example 2)

As the pressure loss portion 17 interposed between the auxiliary heat exchange portion 15a and the auxiliary heat exchange portion 15b, for example, a throttle device may be used.

Fig. 14 shows an expansion device 39 provided for each path (passage) from the 1 st heat transfer pipe 33a to the 2 nd heat transfer pipe 33b with respect to the plurality of 1 st heat transfer pipes 33a arranged in the auxiliary heat exchanger portion 15a and the plurality of 2 nd heat transfer pipes 33b arranged in the auxiliary heat exchanger portion 15 b. Fig. 15 shows an expansion device 39 provided in a manner such that the refrigerant flowing through each of the plurality of 1 st heat transfer tubes 33a merges on the upstream side of the expansion device, is branched (distributed) again on the downstream side of the expansion device, and is sent to each of the plurality of 2 nd heat transfer tubes 33 b.

In the auxiliary heat exchange portion 15, the opening degree of the expansion device 39 is adjusted with respect to the temperature of the refrigerant on the upstream side of the expansion device 39, and the temperature of the refrigerant on the downstream side of the expansion device 39 can be adjusted. That is, by providing the expansion device 39 between the auxiliary

heat exchange units

15a and 15b (between the columns), the temperature of the refrigerant flowing through the auxiliary heat exchange unit 15a located on the upwind side and the temperature of the refrigerant flowing through the auxiliary heat exchange unit 15b located on the downwind side can be separately adjusted.

Thus, all of the auxiliary heat exchange units 15a located on the upwind side can function as condensers, and all of the auxiliary heat exchange units 15b located on the downwind side can function as evaporators. As a result, as described in embodiment 1, when the outdoor heat exchanger 11 is operated as an evaporator, frost can be prevented from adhering to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11.

(example 3)

As the pressure loss portion 17 interposed between the auxiliary heat exchange portion 15a and the auxiliary heat exchange portion 15b, for example, a header (inter-column header) may be used.

Fig. 16 shows the inter-row header 41 disposed between the auxiliary heat exchange portion 15a and the auxiliary heat exchange portion 15 b. As shown in fig. 17, 18, and 19, a flow path through which the refrigerant flows is provided in each path (passage) from the 1 st heat transfer tube 33a to the 2 nd heat transfer tube 33b in the header 41 between the columns. A throttle portion 43 having a smaller cross-sectional area of the flow path than the other flow paths is formed in the middle of the flow path.

By adjusting the width of the expansion portion 43 and the length of the flow path of the expansion portion 43, the pressure loss can be adjusted in the front and rear direction of the inter-row header 41, and the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15a and the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15b can be separately adjusted. This makes it possible to cause the auxiliary heat exchange unit 15a to function as a condenser and the auxiliary heat exchange unit 15b to function as an evaporator, and to prevent frost from adhering to the auxiliary heat exchange unit 15 of the outdoor heat exchanger 11 during operation in which the outdoor heat exchanger 11 operates as an evaporator.

(example 4)

As the pressure loss portion 17 interposed between the auxiliary heat exchange portion 15a and the auxiliary heat exchange portion 15b, for example, two headers, that is, a header connected to the auxiliary heat exchange portion 15a and a header connected to the auxiliary heat exchange portion 15b, may be used.

Fig. 20 shows a header including a header 45a, a header 45b, and a header connection pipe 47. The header 45a is connected to the 1 st heat transfer pipe 33a of the auxiliary heat exchange portion 15 a. The header 45b is connected to the 2 nd heat transfer pipe 33b of the auxiliary heat exchange portion 15 b. A header connection pipe 47 connects between the header 45a and the header 45 b.

In this case, for example, by adjusting the inner diameter of the header connection pipe 47 as the throttle portion 43, the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15a and the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15b can be separately adjusted, and frost can be prevented from adhering to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11 during an operation in which the outdoor heat exchanger 11 operates as an evaporator. Further, a flow path generating friction loss is separately provided in the flow path of the

headers

45a and 45b, and the adhesion of frost can also be prevented by adjusting the pressure loss by adjusting the shape of the flow path.

(example 5)

As the pressure loss section 17 interposed between the auxiliary heat exchange section 15a and the auxiliary heat exchange section 15b, for example, a U-shaped pipe may be used in addition to the header.

As shown in fig. 21, U-shaped tubes 49 are connected to each path (passage) from the 1 st heat transfer tube 33a to the 2 nd heat transfer tube 33 b. In this case, by adjusting the inner diameter of the U-shaped tube 49, the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15a and the temperature of the refrigerant flowing through the auxiliary heat exchange portion 15b can be separately adjusted, and frost can be prevented from adhering to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11 during operation in which the outdoor heat exchanger 11 operates as an evaporator.

As the refrigerant used in the air-conditioning apparatus 1 described in the above embodiment, any of the refrigerants such as the refrigerant R410A, the refrigerant R407C, the refrigerant R32, the refrigerant R507A, and the refrigerant HFO1234yf can be used to prevent frost from adhering to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11.

Refrigerant R410A and refrigerant R407C are mixed refrigerants, and are particularly called non-azeotropic mixed refrigerants. The non-azeotropic mixed refrigerant has a property that the composition is different between a gas phase and a liquid phase in a wet vapor state, and the non-azeotropic mixed refrigerant has a phase change of evaporating or condensing at a constant pressure accompanied by composition change and temperature change between the two phases of the gas refrigerant and the liquid refrigerant. The refrigerant R407C and the like in the non-azeotropic refrigerant mixture have extremely small temperature changes at the time of phase change, and are particularly called a near-azeotropic refrigerant mixture.

Refrigerant R32 and refrigerant HFO1234yf are single-component refrigerants. Refrigerant R507A is a mixed refrigerant, and is called an azeotropic mixed refrigerant. The azeotropic refrigerant mixture has a property of having a composition equal to that of the vapor phase and the liquid phase of the wet vapor at a certain composition ratio, and causing a phase change of evaporation or condensation in a state where the temperature is kept constant under a constant pressure, as in the case of the single-component refrigerant.

Even when such a non-azeotropic refrigerant mixture, a near-azeotropic refrigerant mixture, a single-component refrigerant, or an azeotropic refrigerant mixture is used, when the refrigerant outlet temperature is lower than the freezing point of water (for example, 0 ℃), frost can be prevented from adhering to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11 by operating the refrigerant heat exchanger such that the refrigerant inlet temperature is higher than the outside air temperature and the refrigerant outlet temperature is lower than the outside air temperature. Further, by operating the auxiliary heat exchange unit 15 so that the refrigerant outlet temperature thereof is higher than the dew point temperature, frost can be reliably prevented from adhering to the auxiliary heat exchange unit 15.

As the refrigerating machine oil used in the air conditioner, a refrigerating machine oil having compatibility is used in consideration of mutual solubility with a refrigerant to be used. For example, in the fluorocarbon refrigerant such as the refrigerant R410A, an alkylbenzene oil-based, ester oil-based, or ether oil-based refrigerator oil is used. In addition, a mineral oil-based or fluorine oil-based refrigerating machine oil may be used.

Even when these refrigerating machine oils are used, when the refrigerant outlet temperature is lower than the freezing point of water (for example, 0 ℃), frost can be prevented from adhering to the auxiliary heat exchange portion 15 of the outdoor heat exchanger 11 by operating the refrigerator machine such that the refrigerant inlet temperature is higher than the outside air temperature and the refrigerant outlet temperature is lower than the outside air temperature.

In the above-described embodiment, the refrigeration cycle apparatus is described by taking an air conditioner as an example. The refrigeration cycle apparatus is not limited to an air conditioner, and may be applied to an apparatus in which an outdoor heat exchanger exchanges heat with air, such as a heat pump water heater. The refrigeration cycle apparatus including the outdoor heat exchanger described in the embodiments can be variously combined as necessary.

The embodiments disclosed herein are illustrative, and not restrictive. The present invention is defined by the claims, rather than the scope of the foregoing description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Industrial applicability

The present invention is effectively applied to a refrigeration cycle apparatus such as an air conditioner having an outdoor heat exchanger provided with a main heat exchange unit and an auxiliary heat exchange unit.

Description of the reference numerals

1: air conditioning apparatus, 3: compressor, 5: indoor heat exchanger, 7: indoor fan, 9: throttling device, 11: outdoor heat exchanger, 13: main heat exchange portions, 13a, 13 b: main heat exchange portion, 15: auxiliary heat exchange portions, 15a, 15 b: auxiliary heat exchange portion, 17: pressure loss unit, 21: outdoor fan, 23: four-way valve, 25: a dispenser, 27: header, 29: dispenser, 31: fin, 33: flat tubes, 33 a: 1 st heat transfer pipe, 33 b: heat transfer tube 2, 33 c: heat transfer tube No. 3, 33 d: 4 th heat transfer tube, 35: refrigerant passage, 37: refrigerant pipe, 39: throttle device, 41: inter-row header, 43: throttle portion, 45a, 45 b: header, 47: header connection pipe, 49: u-shaped tube, 51: control unit, 53, 55, 57: a temperature sensor.

Claims

1. A refrigeration cycle device is provided with an outdoor heat exchanger, wherein,

the outdoor heat exchanger includes:

1 st heat exchange part; and

a 2 nd heat exchange part arranged in line with the 1 st heat exchange part,

the 1 st heat exchange unit includes:

a plurality of plate-shaped fins;

a 1 st heat transfer pipe arranged so as to penetrate the plurality of fins;

a 2 nd heat transfer tube that is disposed so as to penetrate the plurality of fins with a distance therebetween in a direction intersecting the direction in which the 1 st heat transfer tube extends; and

a pressure loss mechanism for reducing the pressure of the refrigerant flowing through the 1 st heat exchange unit,

when the outdoor heat exchanger operates as an evaporator, the outdoor heat exchanger is operated such that the temperature of the refrigerant flowing out of the 1 st heat exchange unit is lower than the freezing point of water, the temperature of the refrigerant flowing into the 1 st heat exchange unit is higher than the temperature of the outside air, and the temperature of the refrigerant flowing out of the 1 st heat exchange unit is lower than the temperature of the outside air.

2. The refrigeration cycle apparatus according to claim 1,

during the operation, the operation is performed such that the temperature of the refrigerant flowing out of the 1 st heat exchange unit is higher than the dew point temperature.

3. The refrigeration cycle apparatus according to claim 1,

the 1 st heat transfer tube has a 1 st end portion and a 2 nd end portion,

the 2 nd heat transfer tube has a 3 rd end portion and a 4 th end portion,

the 3 rd end portion of the 2 nd heat transfer pipe is joined to the 2 nd end portion of the 1 st heat transfer pipe,

the 4 th end portion of the 2 nd heat transfer pipe is connected to the 2 nd heat exchange portion.

4. The refrigeration cycle apparatus according to claim 3, wherein,

the pressure loss mechanism includes a throttle portion interposed between the 2 nd end portion of the 1 st heat transfer pipe and the 3 rd end portion of the 2 nd heat transfer pipe,

the throttle portion includes:

a 1 st flow path having a 1 st cross-sectional area; and

a 2 nd flow path having a 2 nd cross-sectional area smaller than the 1 st cross-sectional area.

5. The refrigeration cycle apparatus according to claim 4, wherein,

the throttle unit includes a throttle adjustment unit that adjusts the 2 nd cross-sectional area of the 2 nd flow path.

6. The refrigeration cycle apparatus according to claim 1,

the pressure loss mechanism includes the 1 st heat transfer pipe and the 2 nd heat transfer pipe.

7. The refrigeration cycle apparatus according to claim 1,

the 1 st heat transfer tube is a 1 st flat tube having a flat cross-sectional shape with a major diameter and a minor diameter,

the 2 nd heat transfer tube is a 2 nd flat tube having the flat cross-sectional shape and spaced apart from the 1 st flat tube in the direction of the major axis.

8. The refrigeration cycle apparatus according to claim 1,

the refrigeration cycle device is provided with a blowing part which makes air flow from the side where the 1 st heat transfer pipe is arranged to the side where the 2 nd heat transfer pipe is arranged,

the refrigerant flows from the 1 st heat transfer tube to the 2 nd heat transfer tube.