WO2021250738A1

WO2021250738A1 - Air conditioner

Info

Publication number: WO2021250738A1
Application number: PCT/JP2020/022527
Authority: WO
Inventors: 昭憲坂部
Original assignee: 三菱電機株式会社
Priority date: 2020-06-08
Filing date: 2020-06-08
Publication date: 2021-12-16

Abstract

This air conditioner comprises: a refrigeration cycle circuit having a compressor, a plurality of flow path switching devices which switch a flow path of a refrigerant, a first outdoor heat exchanger, a second outdoor heat exchanger, an expansion valve, and an indoor heat exchanger; an outdoor unit which stores the compressor, the plurality of flow path switching devices, the first outdoor heat exchanger, the second outdoor heat exchanger, and the expansion valve; and an indoor unit which stores the indoor heat exchanger, wherein switching the flow path of the refrigeration by means of the plurality of flow patch switching devices causes the refrigeration cycle circuit, during a cooling operation, to serve as a flow path through which the refrigerant flows in the order of the compressor, the first outdoor heat exchanger, the second outdoor heat exchanger, the expansion valve, and the indoor heat exchanger, and causes the refrigeration cycle circuit, during a heating operation, to serve as a flow path through which the refrigerant flows in the order of the compressor, the indoor heat exchanger, the second outdoor heat exchanger, the expansion valve, and the first outdoor heat exchanger.

Description

Air conditioner

This disclosure relates to an air conditioner capable of cooling operation and heating operation.

Conventionally, an air conditioner capable of cooling operation and heating operation is known. In such an air conditioner, the indoor heat exchanger housed in the indoor unit functions as an evaporator and the outdoor heat exchanger housed in the outdoor unit functions as a condenser during the cooling operation. Further, in such an air conditioner, the indoor heat exchanger functions as a condenser and the outdoor heat exchanger functions as an evaporator during the heating operation. In this way, in an air conditioner capable of cooling operation and heating operation, the role of the indoor heat exchanger and the role of the outdoor heat exchanger are reversed between the cooling operation and the heating operation. That is, in an air conditioner capable of cooling operation and heating operation, it is necessary for the outdoor heat exchanger to play the roles of both an evaporator and a condenser. Therefore, in order to improve the performance of the air conditioner capable of cooling operation and heating operation, it is necessary to improve at least one of the condensation performance during the cooling operation and the evaporation performance during the heating operation.

Therefore, a conventional air conditioner capable of cooling operation and heating operation has been proposed in which an auxiliary heat exchanger is provided between a heat exchanger functioning as a condenser and an expansion valve (patented). See Document 1). This auxiliary heat exchanger is housed in the outdoor unit. In the auxiliary heat exchanger, the refrigerant flowing out of the heat exchanger functioning as a condenser is cooled by the low-temperature low-pressure refrigerant sucked into the compressor. Therefore, the degree of supercooling of the refrigerant flowing out of the condenser can be increased. As a result, the refrigerant having a low enthalpy flows into the evaporator, and the difference in enthalpy of the refrigerant flowing through the evaporator can be increased, so that the evaporation performance of the evaporator can be improved. As described above, the air conditioner described in Patent Document 1 is provided with an auxiliary heat exchanger to increase the degree of overcooling of the refrigerant flowing out from the indoor heat exchanger during the heating operation, thereby increasing the degree of overcooling of the outdoor heat exchanger. We are trying to improve the evaporation performance of.

Japanese Unexamined Patent Publication No. 11-14167

Conventionally, the outdoor unit of an air conditioner may be required to be downsized. In such a case, the capacity of the auxiliary heat exchanger that can be stored in the outdoor unit becomes small, and the evaporation performance cannot be improved during the heating operation. That is, the air conditioner described in Patent Document 1 has a problem that the performance cannot be improved when the capacity of the auxiliary heat exchanger must be reduced.

The present disclosure has been made in order to solve the above-mentioned problems, and it is possible to improve the performance of an air conditioner capable of cooling operation and heating operation without providing an auxiliary heat exchanger. The purpose is to provide an opportunity.

The air conditioner according to the present disclosure is a refrigeration cycle having a compressor, a plurality of flow path switching devices for switching the flow path of the refrigerant, a first outdoor heat exchanger, a second outdoor heat exchanger, an expansion valve and an indoor heat exchanger. The circuit, the compressor, the plurality of flow path switching devices, the first outdoor heat exchanger, the second outdoor heat exchanger, the outdoor unit in which the expansion valve is housed, and the indoor heat exchanger are housed. By switching the flow path of the refrigerant with the plurality of flow path switching devices, the refrigerating cycle circuit may be the compressor, the first outdoor heat exchanger, and the second indoor unit during the cooling operation. The configuration is such that the flow path is such that the refrigerant flows in the order of the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger, and during the heating operation, the refrigeration cycle circuit is the compressor, the indoor heat exchanger, and the second. The configuration is such that the flow path is such that the refrigerant flows in the order of the outdoor heat exchanger, the expansion valve, and the first outdoor heat exchanger.

In the air conditioner according to the present disclosure, both the first outdoor heat exchanger and the second outdoor heat exchanger function as condensers during the cooling operation. Therefore, the air conditioner according to the present disclosure can improve the condensation performance during the cooling operation. Further, in the air conditioner according to the present disclosure, the indoor heat exchanger and the second outdoor heat exchanger function as condensers during the heating operation. Therefore, the refrigerant flowing out of the indoor heat exchanger is cooled to the outside air in the second outdoor heat exchanger, and the degree of supercooling increases. Therefore, in the air conditioner according to the present disclosure, the difference in enthalpy of the refrigerant flowing through the first outdoor heat exchanger functioning as an evaporator can be increased during the heating operation, so that the evaporation performance can be improved. .. Therefore, the air conditioner according to the present disclosure can improve the performance even if it does not include the auxiliary heat exchanger shown in Patent Document 1.

It is a refrigerant circuit diagram which shows the air conditioner which concerns on this Embodiment 1. It is a refrigerant circuit diagram which shows the air conditioner which concerns on this Embodiment 1. It is a pressure-enthalpy diagram which shows the refrigerating cycle at the time of the heating operation of the air conditioner which concerns on Embodiment 1. It is a refrigerant circuit diagram which shows the air conditioner which concerns on this Embodiment 2. It is a refrigerant circuit diagram which shows the air conditioner which concerns on this Embodiment 2.

Embodiment 1.
1 and 2 are refrigerant circuit diagrams showing an air conditioner according to the first embodiment. Note that FIG. 1 shows a state in which the air conditioner 100 according to the first embodiment is in a heating operation. Further, FIG. 2 shows a state in which the air conditioner 100 according to the first embodiment is in a cooling operation. The black arrows shown in FIGS. 1 and 2 indicate the flow direction of the refrigerant. Further, the white arrows shown in the vicinity of the outdoor blower 31 in FIGS. 1 and 2 indicate the flow direction of the outside air supplied from the outdoor blower 31 to the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20. There is. Further, the white arrows shown in the vicinity of the indoor blower 32 in FIGS. 1 and 2 indicate the flow direction of the indoor air supplied from the indoor blower 32 to the indoor heat exchanger 7.

The air conditioner 100 includes a refrigeration cycle circuit 1, an outdoor unit 110, and an indoor unit 120. Further, the refrigeration cycle circuit 1 has a plurality of switches between the compressor 2, the first outdoor heat exchanger 10, the second outdoor heat exchanger 20, the expansion valve 6, the indoor heat exchanger 7, and the flow path of the refrigerant. It is equipped with a flow path switching device.

The compressor 2 compresses the refrigerant. The compressor 2 includes a suction port for sucking the compressed refrigerant and a discharge port for discharging the compressed refrigerant. The compressor 2 can be composed of, for example, a rotary compressor, a scroll compressor, a screw compressor, a reciprocating compressor, and the like.

The first outdoor heat exchanger 10 functions as a condenser during the cooling operation and as an evaporator during the heating operation. The first outdoor heat exchanger 10 includes, for example, a fin-and-tube heat exchanger, a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, a double-tube heat exchanger, and a plate. It can be configured with a heat exchanger or the like. Further, in the first embodiment, the first outdoor heat exchanger 10 has a configuration in which a plurality of first refrigerant flow paths 11 are formed in parallel. The first outdoor heat exchanger 10 includes a distributor 12 that distributes the refrigerant to each of the first refrigerant flow paths 11 during the heating operation. Specifically, during the heating operation, the refrigerant flowing into the first outdoor heat exchanger 10 first flows into the distributor 12 and is distributed to the first refrigerant flow path 11. During the cooling operation, the refrigerant flowing out of each of the first refrigerant flow paths 11 flows into the distributor 12, merges, and flows out from the distributor 12. That is, the distributor 12 functions as a merging device during the cooling operation. Further, the first outdoor heat exchanger 10 includes a merging device 13 in which the refrigerant flowing out from each first refrigerant flow path 11 merges during the heating operation. Specifically, during the heating operation, the refrigerant flowing out from each of the first refrigerant flow paths 11 flows into the merging device 13 and merges, and then flows out from the merging device 13. During the cooling operation, the refrigerant flowing into the first outdoor heat exchanger 10 first flows into the merging device 13 and is distributed to each first refrigerant flow path 11. That is, the merging device 13 functions as a distributor during the cooling operation.

The second outdoor heat exchanger 20 functions as a condenser in both the cooling operation and the heating operation. The second outdoor heat exchanger 20 includes, for example, a fin-and-tube heat exchanger, a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, a double-tube heat exchanger, and a plate. It can be configured with a heat exchanger or the like. Further, in the first embodiment, the second outdoor heat exchanger 20 has a configuration in which one second refrigerant flow path 21 is formed. The second outdoor heat exchanger 20 may have a configuration in which a plurality of second refrigerant flow paths 21 are formed in parallel. Here, in the first embodiment, the number of the second refrigerant flow paths 21 is smaller than the number of the first refrigerant flow paths 11.

The expansion valve 6 expands the high-pressure liquid refrigerant flowing out of the second outdoor heat exchanger 20 to reduce the pressure to obtain a low-temperature, low-pressure gas-liquid two-phase refrigerant. The expansion valve 6 can be composed of, for example, an electronic expansion valve or the like whose flow rate of the refrigerant can be adjusted.

The indoor heat exchanger 7 functions as an evaporator during the cooling operation and as a condenser during the heating operation. The indoor heat exchanger 7 includes, for example, a fin-and-tube heat exchanger, a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, a double-tube heat exchanger, and a plate heat exchanger. It can be composed of a vessel or the like.

The plurality of flow path switching devices switch the flow path of the refrigerant of the refrigerating cycle circuit 1 between the cooling operation and the heating operation. Each of the flow path switching devices is composed of, for example, a four-way valve. In addition, each of the flow path switching devices may be configured by combining a plurality of two-way valves, for example. In the first embodiment, as a plurality of flow path switching devices, a flow path switching device 3, a flow path switching device 4, and a flow path switching device 5 are provided.

The flow path switching device 3 switches between a heat exchanger connected to the discharge port of the compressor 2 and a heat exchanger connected to the suction port of the compressor 2 during cooling operation and heating operation. be. Specifically, during the cooling operation, in the flow path switching device 3, the discharge port of the compressor 2 and the first outdoor heat exchanger 10 are connected, and the suction port of the compressor 2 and the indoor heat exchanger 7 are connected. It becomes a flow path to be processed. Further, during the heating operation, in the flow path switching device 3, the discharge port of the compressor 2 and the indoor heat exchanger 7 are connected, and the suction port of the compressor 2 and the first outdoor heat exchanger 10 are connected. It becomes a road.

The flow path switching device 4 and the flow path switching device 5 switch the heat exchanger connected to the inlet of the refrigerant of the second outdoor heat exchanger 20 between the cooling operation and the heating operation. Specifically, during the cooling operation, the flow path switching device 4 and the flow path switching device 5 are connected to the flow path to which the refrigerant inlet of the second outdoor heat exchanger 20 and the first outdoor heat exchanger 10 are connected. Become. That is, during the cooling operation, the refrigerant flowing out of the first outdoor heat exchanger 10 flows into the second outdoor heat exchanger 20. Further, during the heating operation, the flow path switching device 4 and the flow path switching device 5 become a flow path in which the inlet of the refrigerant of the second outdoor heat exchanger 20 and the indoor heat exchanger 7 are connected. That is, during the heating operation, the refrigerant flowing out of the indoor heat exchanger 7 flows into the second outdoor heat exchanger 20. In both the cooling operation and the heating operation, the flow path switching device 4 and the flow path switching device 5 are flow paths in which the outlet of the refrigerant of the second outdoor heat exchanger 20 is connected to the expansion valve 6. ..

Each of the above-mentioned configurations of the refrigeration cycle circuit 1 is housed in the outdoor unit 110 or the indoor unit 120. Specifically, the outdoor unit 110 includes a compressor 2, a flow path switching device 3, a flow path switching device 4, a flow path switching device 5, a first outdoor heat exchanger 10, a second outdoor heat exchanger 20, and the like. The expansion valve 6 is housed. The indoor unit 120 houses the indoor heat exchanger 7. Further, the outdoor unit 110 also houses an outdoor blower 31 that supplies outside air to the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20. Further, the indoor unit 120 also houses an indoor blower 32 that supplies indoor air to the indoor heat exchanger 7.

Next, the operation of the air conditioner 100 will be described.

FIG. 3 is a pressure-enthalpy diagram showing a refrigeration cycle during heating operation of the air conditioner according to the first embodiment. In FIG. 3, the vertical axis is the pressure P and the horizontal axis is the enthalpy H.
First, the operation of the air conditioner 100 during the heating operation will be described with reference to FIGS. 1 and 3.

By switching the flow path of the refrigerant with the flow path switching device 3, the flow path switching device 4, and the flow path switching device 5, during the heating operation, the refrigerating cycle circuit 1 uses the compressor 2, the indoor heat exchanger 7, and the second. The flow path is such that the refrigerant flows in the order of the outdoor heat exchanger 20, the expansion valve 6, and the first outdoor heat exchanger 10. As a result, in the refrigeration cycle circuit 1, the refrigerant flows as shown by the black arrow in FIG.

Specifically, the low-pressure gaseous refrigerant shown as the state e in FIG. 3 is sucked into the compressor 2 and compressed, and discharged from the compressor 2 as the high-temperature and high-pressure gaseous refrigerant shown as the state a in FIG. To. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 2 passes through the flow path switching device 3 and flows out from the outdoor unit 110. Then, the high-temperature, high-pressure gaseous refrigerant flowing out of the outdoor unit 110 flows into the indoor unit 120 and flows into the indoor heat exchanger 7 that functions as a condenser. The high-temperature, high-pressure gaseous refrigerant flowing into the indoor heat exchanger 7 is cooled by the indoor air and condensed when heating the indoor air supplied from the indoor blower 32 to the indoor heat exchanger 7, and is shown in FIG. It becomes a high-pressure liquid refrigerant shown as the state b and flows out from the indoor heat exchanger 7. The high-pressure liquid refrigerant flowing out of the indoor heat exchanger 7 flows out from the indoor unit 120 and flows into the outdoor unit 110.

The high-pressure liquid refrigerant that has flowed into the outdoor unit 110 flows into the second outdoor heat exchanger 20 through the flow path switching device 5. The high-pressure liquid refrigerant that has flowed into the second outdoor heat exchanger 20 exchanges heat with the outside air supplied from the outdoor blower 31 to the second outdoor heat exchanger 20. Here, during the heating operation, the temperature of the outside air is usually lower than the temperature of the indoor air. Therefore, the high-pressure liquid refrigerant that has flowed into the second outdoor heat exchanger 20 is cooled by the outside air, the degree of supercooling increases as shown in the state c in FIG. 3, and the refrigerant flows out of the second outdoor heat exchanger 20. .. The high-pressure liquid refrigerant flowing out of the second outdoor heat exchanger 20 flows into the expansion valve 6 through the flow path switching device 4.

The high-pressure liquid refrigerant flowing into the expansion valve 6 expands enthalpy in the expansion valve 6 and becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant shown in the state d in FIG. 3 and flows out from the expansion valve 6. The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing out of the expansion valve 6 flows into the first outdoor heat exchanger 10 functioning as an evaporator through the flow path switching device 5 and the flow path switching device 4. More specifically, the low-temperature, low-pressure gas-liquid two-phase refrigerant flowing out of the expansion valve 6 flows into the distributor 12 of the first outdoor heat exchanger 10. Then, the low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed into the distributor 12 is distributed to each of the first refrigerant flow paths 11. The low-temperature, low-pressure gas-liquid two-phase refrigerant distributed to each first refrigerant flow path 11 is heated by the outside air supplied from the outdoor blower 31 to the first outdoor heat exchanger 10 and evaporates, and the state e in FIG. It becomes a low-pressure gaseous refrigerant shown as, and flows out from each first refrigerant flow path 11. The low-pressure gaseous refrigerant flowing out of each first refrigerant flow path 11 merges with the merging device 13 and then flows out from the merging device 13. That is, the low-pressure gaseous refrigerant flowing out from each first refrigerant flow path 11 merges with the merging device 13 and then flows out from the first outdoor heat exchanger 10. The low-pressure gaseous refrigerant flowing out of the first outdoor heat exchanger 10 is sucked into the compressor 2 and compressed again.

Here, when the second outdoor heat exchanger 20 is not provided, the low-pressure liquid refrigerant shown as the state b in FIG. 3 expands enthalpy in the expansion valve 6, and the low-temperature low-pressure air shown in the state f in FIG. 3 expands. The liquid two-phase refrigerant will flow into the first outdoor heat exchanger 10. Therefore, during the heating operation, the air conditioner 100 according to the first embodiment is a refrigerant flowing through the first outdoor heat exchanger 10 that functions as an evaporator, as compared with the case where the second outdoor heat exchanger 20 is not provided. The enthalpy difference can be increased by the difference between the state f and the state d. Therefore, during the heating operation, the air conditioner 100 according to the first embodiment can improve the evaporation performance as compared with the case where the second outdoor heat exchanger 20 is not provided, so that the heating performance can be improved. Can be done.

Further, when the gas-liquid two-phase refrigerant is distributed from the distributor 12 to each of the first refrigerant flow paths 11, the gas-liquid two-phase refrigerant having a lower dryness and a larger ratio of the liquid refrigerant has a higher ratio of the liquid refrigerant, the more each first refrigerant flow path 11. The gas-liquid two-phase refrigerant can be evenly distributed to the water. It is generally difficult to evenly distribute the mass flow rate of the refrigerant due to the drift of the liquid refrigerant in the distribution of the gas-liquid two-phase refrigerant. This is because even distribution of the flow rate becomes easy. As can be seen from FIG. 3, the air conditioner 100 according to the first embodiment provided with the second outdoor heat exchanger 20 has a first outdoor heat exchange as compared with the case where the second outdoor heat exchanger 20 is not provided. The dryness of the gas-liquid two-phase refrigerant flowing into the vessel 10 becomes low. Therefore, when the first outdoor heat exchanger 10 is configured to distribute the gas-liquid two-phase refrigerant to the plurality of first refrigerant flow paths 11, the air conditioner 100 according to the first embodiment is the second. Compared with the case where the outdoor heat exchanger 20 is not provided, the evaporation performance can be further improved, and the heating performance can be further improved.

Next, the operation of the air conditioner 100 during the cooling operation will be described with reference to FIG.

By switching the flow path of the refrigerant with the flow path switching device 3, the flow path switching device 4, and the flow path switching device 5, during the cooling operation, the refrigerating cycle circuit 1 uses the compressor 2, the first outdoor heat exchanger 10, and the refrigerating cycle circuit 1. The flow path is such that the refrigerant flows in the order of the second outdoor heat exchanger 20, the expansion valve 6, and the indoor heat exchanger 7. As a result, in the refrigeration cycle circuit 1, the refrigerant flows as shown by the black arrow in FIG.

Specifically, the low-pressure gaseous refrigerant is sucked into the compressor 2 and compressed, and is discharged from the compressor 2 as a high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 2 flows into the first outdoor heat exchanger 10 through the flow path switching device 3. The high-temperature, high-pressure gaseous refrigerant that has flowed into the first outdoor heat exchanger 10 is cooled and condensed by the outside air supplied from the outdoor blower 31 to the first outdoor heat exchanger 10, and is a high-pressure liquid refrigerant or high-pressure air. It becomes a liquid two-phase refrigerant and flows out from the first outdoor heat exchanger 10. The high-pressure refrigerant flowing out of the first outdoor heat exchanger 10 flows into the second outdoor heat exchanger 20 through the flow path switching device 4. The high-pressure refrigerant flowing into the second outdoor heat exchanger 20 is further cooled by the outside air supplied from the outdoor blower 31 to the second outdoor heat exchanger 20 to become a high-pressure liquid refrigerant, and becomes the second outdoor heat exchanger 20. Outflow from. The high-pressure liquid refrigerant flowing out of the second outdoor heat exchanger 20 flows into the expansion valve 6 through the flow path switching device 5.

The high-pressure liquid refrigerant flowing into the expansion valve 6 expands equienthalpy in the expansion valve 6, becomes a low-temperature gas-liquid two-phase refrigerant, and flows out from the expansion valve 6. The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing out of the expansion valve 6 flows out from the outdoor unit 110 through the flow path switching device 4 and the flow path switching device 5. Then, the low-temperature, low-pressure gas-liquid two-phase refrigerant flowing out of the outdoor unit 110 flows into the indoor unit 120 and flows into the indoor heat exchanger 7 that functions as an evaporator. The low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor heat exchanger 7 is heated by the indoor air and evaporated when the indoor air supplied from the indoor blower 32 to the indoor heat exchanger 7 is cooled, resulting in low pressure. It becomes a gaseous refrigerant of the above and flows out from the indoor heat exchanger 7. The low-pressure gaseous refrigerant flowing out of the indoor heat exchanger 7 flows out of the indoor unit 120 and flows into the outdoor unit 110. Then, the low-pressure gaseous refrigerant flowing into the outdoor unit 110 passes through the flow path switching device 3, is sucked into the compressor 2, and is compressed again.

As described above, in the air conditioner 100 according to the first embodiment, both the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20 function as condensers during the cooling operation. Therefore, the air conditioner 100 according to the first embodiment can improve the condensation performance during the cooling operation, so that the cooling performance can be improved.

As described above, the air conditioner 100 according to the first embodiment includes a refrigerating cycle circuit 1, an outdoor unit 110, and an indoor unit 120. Further, the refrigeration cycle circuit 1 includes a compressor 2, a plurality of flow path switching devices for switching the flow path of the refrigerant, a first outdoor heat exchanger 10, a second outdoor heat exchanger 20, and an expansion valve 6. It is equipped with an indoor heat exchanger 7. The outdoor unit 110 houses a compressor 2, a plurality of flow path switching devices for switching the flow path of the refrigerant, a first outdoor heat exchanger 10, a second outdoor heat exchanger 20, and an expansion valve 6. The indoor unit 120 houses the indoor heat exchanger 7. Further, in the air conditioner 100 according to the first embodiment, by switching the flow path of the refrigerant with a plurality of flow path switching devices, the refrigerating cycle circuit 1 uses the compressor 2 and the first outdoor heat during the cooling operation. The flow path is such that the refrigerant flows in the order of the exchanger 10, the second outdoor heat exchanger 20, the expansion valve 6, and the indoor heat exchanger 7. Further, in the air conditioner 100 according to the first embodiment, by switching the flow path of the refrigerant with a plurality of flow path switching devices, the refrigerating cycle circuit 1 is the compressor 2 and the indoor heat exchanger during the heating operation. 7. The flow path is such that the refrigerant flows in the order of the second outdoor heat exchanger 20, the expansion valve 6, and the first outdoor heat exchanger 10.

Therefore, as described above, the air conditioner 100 according to the first embodiment can improve the condensation performance during the cooling operation even if the auxiliary heat exchanger shown in Patent Document 1 is not provided. , Cooling performance can be improved. Further, as described above, the air conditioner 100 according to the first embodiment can improve the evaporation performance during the heating operation even if the auxiliary heat exchanger shown in Patent Document 1 is not provided. The heating performance can be improved. Therefore, the air conditioner 100 according to the first embodiment can improve the performance even if it does not include the auxiliary heat exchanger shown in Patent Document 1.

Further, as described above, in the first embodiment, the number of the second refrigerant flow paths 21 of the second outdoor heat exchanger 20 is larger than the number of the first refrigerant flow paths 11 of the first outdoor heat exchanger 10. Is also decreasing. Therefore, the air conditioner 100 according to the first embodiment can further improve the performance as described below.

Generally, the pressure loss generated in the refrigeration cycle circuit contributes to the deterioration of the performance of the refrigeration cycle circuit. Specifically, the pressure loss generated in the refrigeration cycle circuit depends on the flow rate of the refrigerant. Further, when comparing the low-pressure refrigerant having the same mass flow rate and the high-pressure liquid refrigerant, the low-density low-pressure refrigerant has a higher flow velocity, and the high-pressure liquid refrigerant has a slower flow rate. Therefore, the pressure loss generated in the refrigeration cycle circuit becomes large in the region where the low pressure refrigerant flows. Therefore, by increasing the number of refrigerant flow paths formed in parallel in the evaporator through which the low-pressure refrigerant flows and reducing the flow velocity of the low-pressure refrigerant in the evaporator, it is possible to suppress the pressure loss generated in the refrigeration cycle circuit. The performance of the refrigeration cycle circuit can be improved. On the other hand, in a condenser through which a high-pressure liquid refrigerant flows, the pressure loss generated is not large. Therefore, in the condenser, the heat exchange performance of the condenser is improved by reducing the number of refrigerant channels to increase the flow velocity of the refrigerant and improving the heat transfer coefficient between the refrigerant and air. That is, the performance of the refrigeration cycle circuit can be improved. Here, in the air conditioner 100 according to the first embodiment, the first outdoor heat exchanger 10 functions as a condenser during the cooling operation and as an evaporator during the heating operation. On the other hand, the second outdoor heat exchanger 20 functions as a condenser through which a high-pressure liquid refrigerant mainly flows in both the cooling operation and the heating operation. Therefore, by reducing the number of the second refrigerant flow paths 21 of the second outdoor heat exchanger 20 to be smaller than the number of the first refrigerant flow paths 11 of the first outdoor heat exchanger 10, the performance of the air conditioner 100 can be improved. It can be further improved.

Further, in the first embodiment, by switching the flow path of the refrigerant of the refrigeration cycle circuit 1 by a plurality of flow path switching devices, the second outdoor room that functions as a condenser during both the cooling operation and the heating operation. The refrigerant flowing out of the heat exchanger 20 is expanded by one expansion valve 6. Therefore, the air conditioner 100 according to the first embodiment can also obtain the following effects.

When referring to the configuration of the conventional refrigerant circuit, the expansion valve that expands the refrigerant that has flowed out of the second outdoor heat exchanger 20 during the cooling operation and the refrigerant that has flowed out of the second outdoor heat exchanger 20 during the heating operation are expanded. It is conceivable to provide an expansion valve in the refrigeration cycle circuit 1. However, when a plurality of expansion valves are provided in the refrigeration cycle circuit 1 in this way, only one of the expansion valves is used during the cooling operation and the heating operation. Therefore, when a plurality of expansion valves are provided in the refrigeration cycle circuit 1, the unused expansion valve, which is an unused expansion valve, has the following configuration.
(1) The flow path of the unused expansion valve is fully closed, and the flow paths before and after the unused expansion valve are shut off.
(2) The flow path of the unused expansion valve is fully opened to suppress the expansion of the refrigerant in the unused expansion valve.
Here, when the unused expansion valve has the configuration of (1), the vicinity of the unused expansion valve is a place where the refrigerant does not flow, so that the refrigerant accumulates in the vicinity of the unused expansion valve, and the refrigerating cycle circuit 1 Performance will be reduced. Further, the flow path of the expansion valve is narrower than the flow path of the piping before and after the expansion valve. Therefore, when the unused expansion valve has the configuration of (2), even if the flow path of the unused expansion valve is fully opened, a pressure loss occurs in the unused expansion valve, and the performance of the refrigeration cycle circuit 1 still deteriorates. It will drop. At this time, when referring to the configuration of the conventional refrigerant circuit, it is conceivable that the configuration around the unused expansion valve is as follows in order to suppress the deterioration of the performance of the refrigeration cycle circuit 1.
(3) Provide a bypass circuit that bypasses the unused expansion valve. The unused expansion valve is fully closed, and a bypass circuit is used to flow the refrigerant from the upstream side to the downstream side of the unused expansion valve.
However, when the periphery of the unused expansion valve is configured as shown in (3), the configuration of the refrigeration cycle circuit 1 becomes complicated. As a result, if the area around the unused expansion valve is configured as shown in (3), there is a problem that the manufacturing cost of the refrigeration cycle circuit 1 increases, and the outdoor unit 110 that houses the configuration around the unused expansion valve The problem of increasing the size arises.

On the other hand, the air conditioner 100 according to the first embodiment expands the refrigerant flowing out from the second outdoor heat exchanger 20 that functions as a condenser in both the cooling operation and the heating operation. It is inflated with a valve 6. Therefore, in the air conditioner 100 according to the first embodiment, there is no unused expansion valve. Therefore, in the air conditioner 100 according to the first embodiment, the performance of the refrigeration cycle circuit 1 does not deteriorate when the unused expansion valve has the above-mentioned configuration (1) or (2). Therefore, in the air conditioner 100 according to the first embodiment, when a plurality of expansion valves are provided in the refrigeration cycle circuit 1 and the unused expansion valves are configured as described in (1) or (2) above. Compared with this, the performance of the refrigeration cycle circuit 1 can be improved. Further, in the air conditioner 100 according to the first embodiment, as compared with the case where the refrigerating cycle circuit 1 is provided with a plurality of expansion valves and the configuration around the unused expansion valves is configured as shown in (3). The configuration of the refrigeration cycle circuit 1 becomes simple. Therefore, in the air conditioner 100 according to the first embodiment, as compared with the case where the refrigerating cycle circuit 1 is provided with a plurality of expansion valves and the configuration around the unused expansion valves is configured as shown in (3). The manufacturing cost of the refrigeration cycle circuit 1 can be reduced, and the outdoor unit 110 can be miniaturized.

When a plurality of expansion valves are provided in the refrigeration cycle circuit 1, the refrigerant is expanded by all the expansion valves in both the cooling operation and the heating operation, that is, all the expansion valves are used. As a result, the above-mentioned pressure loss and accumulation of the refrigerant can be prevented. However, in such a configuration, it is necessary to perform the cooling operation and the heating operation while simultaneously controlling the opening degrees of the plurality of expansion valves, which complicates the control of the refrigeration cycle circuit 1. On the other hand, in the air conditioner 100 according to the first embodiment, it is sufficient to control only the opening degree of one expansion valve 6 during both the cooling operation and the heating operation. Therefore, in the air conditioner 100 according to the first embodiment, the refrigerating cycle circuit 1 can be easily controlled.

Embodiment 2.
In the first embodiment, the arrangement position of the second outdoor heat exchanger 20 with respect to the first outdoor heat exchanger 10 is not particularly limited. For example, the second outdoor heat exchanger 20 may be arranged with respect to the first outdoor heat exchanger 10 as shown in the second embodiment. In the second embodiment, the items not specifically described are the same as those in the first embodiment, and the same functions and configurations as those in the first embodiment are described by using the same reference numerals as those in the first embodiment. ..

4 and 5 are refrigerant circuit diagrams showing the air conditioner according to the second embodiment. Note that FIG. 4 shows a state in which the air conditioner 100 according to the second embodiment is in a heating operation. Further, FIG. 5 shows a state in which the air conditioner 100 according to the second embodiment is in a cooling operation. The black arrows shown in FIGS. 4 and 5 indicate the flow direction of the refrigerant. Further, the white arrows shown in the vicinity of the outdoor blower 31 in FIGS. 4 and 5 indicate the flow direction of the outside air supplied from the outdoor blower 31 to the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20. There is. In other words, the white arrows shown in the vicinity of the outdoor blower 31 in FIGS. 4 and 5 indicate the direction of the flow of outside air generated when the outdoor blower 31 rotates. Further, the white arrows shown in the vicinity of the indoor blower 32 in FIGS. 4 and 5 indicate the flow direction of the indoor air supplied from the indoor blower 32 to the indoor heat exchanger 7.

In the air conditioner 100 according to the second embodiment, the second outdoor heat exchanger 20 is located upstream of the first outdoor heat exchanger 10 in the direction of the flow of outside air generated when the outdoor blower 31 rotates. Have been placed. That is, when the outdoor blower 31 rotates, the outside air is first supplied to the second outdoor heat exchanger 20, and the outside air after passing through the second outdoor heat exchanger 20 is supplied to the first outdoor heat exchanger 10. It has become.

Conventionally, when heating is performed under low outside air temperature conditions, the moisture in the air cooled by the outdoor heat exchanger that functions as an evaporator may adhere to the outdoor heat exchanger as frost. When frost adheres to the outdoor heat exchanger in this way, the surface of the outdoor heat exchanger is covered with frost, and when the flow path of the outside air of the outdoor heat exchanger is narrowed by the frost, the refrigerant and the outside air flowing through the outdoor heat exchanger The heat transfer coefficient with and is significantly reduced. Further, the evaporation temperature of the refrigerant flowing through the outdoor heat exchanger varies depending on the amount of heat exchange between the refrigerant flowing through the outdoor heat exchanger and the outside air. For this reason, if the heat transfer coefficient between the refrigerant flowing through the outdoor heat exchanger and the outside air drops significantly, the evaporation temperature of the refrigerant flowing through the outdoor heat exchanger drops, causing further frost to adhere to the outdoor heat exchanger, creating a vicious cycle. Occurs.

On the other hand, in the air conditioner 100 according to the second embodiment, as shown in FIG. 4, a second outdoor heat exchanger functioning as a condenser is located upstream of the first outdoor heat exchanger 10 functioning as an evaporator during the heating operation. Two outdoor heat exchangers 20 are arranged. Therefore, in the air conditioner 100 according to the second embodiment, the outside air supplied from the outdoor blower 31 to the second outdoor heat exchanger 20 functioning as a condenser is warmed by the second outdoor heat exchanger 20. .. Then, the outside air warmed by the second outdoor heat exchanger 20 is supplied to the first outdoor heat exchanger 10 that functions as an evaporator. That is, in the air conditioner 100 according to the second embodiment, air having a temperature higher than that of the outside air around the outdoor unit 110 is supplied to the first outdoor heat exchanger 10.

Therefore, the air conditioner 100 according to the second embodiment can suppress the adhesion of frost to the first outdoor heat exchanger 10 that functions as an evaporator. Further, the evaporation temperature of the refrigerant flowing through the first outdoor heat exchanger 10 functioning as an evaporator varies depending on the amount of heat exchange between the refrigerant flowing through the first outdoor heat exchanger 10 and air. In the air conditioner 100 according to the second embodiment, since it is possible to suppress the adhesion of frost to the first outdoor heat exchanger 10, it is different from the conventional air conditioner that cannot suppress the adhesion of frost to the outdoor heat exchanger. In comparison, the evaporation temperature of the refrigerant flowing through the first outdoor heat exchanger 10 functioning as an evaporator rises. Therefore, it is possible to further suppress the adhesion of frost to the first outdoor heat exchanger 10 that functions as an evaporator. Therefore, by arranging the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20 as in the second embodiment, the heating performance of the air conditioner 100 can be further improved.

Further, in the air conditioner 100 according to the second embodiment, as described above, the evaporation temperature of the refrigerant flowing through the first outdoor heat exchanger 10 that functions as an evaporator rises, so that the first outdoor heat exchanger 10 is used. The evaporation pressure of the flowing refrigerant also rises. That is, in the air conditioner 100 according to the second embodiment, the pressure of the refrigerant sucked by the compressor 2 increases. Therefore, in the air conditioner 100 according to the second embodiment, the compression ratio of the compressor 2 can be reduced, and the power consumption can also be reduced.

As shown in FIG. 5, in the air conditioner 100 according to the second embodiment, the refrigerant flowing out from the first outdoor heat exchanger 10 functioning as a condenser is the same as in the first embodiment during the cooling operation. , Flows into the second outdoor heat exchanger 20 that functions as a condenser. That is, during the cooling operation, the second outdoor heat exchanger 20 of the air conditioner 100 according to the second embodiment overcools the refrigerant flowing out from the first outdoor heat exchanger 10 as in the first embodiment. It becomes an overcooling heat exchanger. Therefore, the temperature of the refrigerant flowing through the second outdoor heat exchanger 20 is lower than the temperature of the refrigerant flowing through the first outdoor heat exchanger 10.

Therefore, in the air conditioner 100 according to the second embodiment, the outside air supplied from the outdoor blower 31 to the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20 first exchanges the second outdoor heat. It is heated when cooling a refrigerant having a temperature lower than that of the first outdoor heat exchanger 10 flowing through the vessel 20. After that, the air heated by the second outdoor heat exchanger 20 cools the refrigerant having a higher temperature than the second outdoor heat exchanger 20 flowing through the first outdoor heat exchanger 10. That is, in the air conditioner 100 according to the second embodiment, the refrigerant flowing through the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20 functioning as condensers exchanges heat with the outdoor blower 31 to the first outdoor heat exchanger 31. The outside air supplied to the vessel 10 and the second outdoor heat exchanger 20 is so-called air conditioning. Therefore, by arranging the first outdoor heat exchanger 10 and the second outdoor heat exchanger 20 as in the second embodiment, the cooling performance of the air conditioner 100 can be further improved.

Although an example of the air conditioner 100 has been described above in the first and second embodiments, the air conditioner 100 may of course have a configuration not shown in the first and second embodiments. .. For example, the air conditioner 100 includes a gas-liquid separator provided at a position between the expansion valve 6 and the indoor heat exchanger 7 during the cooling operation, and a gaseous refrigerant separated by the gas-liquid separator during the cooling operation. May be provided with a bypass pipe for returning the compressor 2 to the suction side. As a result, of the low-temperature low-pressure gas-liquid two-phase refrigerant expanded by the expansion valve 6 during the cooling operation, only the liquid refrigerant flows into the indoor heat exchanger 7. Therefore, the cooling performance of the air conditioner 100 can be further improved. Further, for example, the air conditioner 100 is separated by a gas-liquid separator provided at a position between the expansion valve 6 and the first outdoor heat exchanger 10 during the heating operation and a gas-liquid separator during the heating operation. A bypass pipe for returning the gaseous refrigerant to the suction side of the compressor 2 may be provided. As a result, the dryness of the refrigerant flowing into the first outdoor heat exchanger 10 during the heating operation can be further reduced, and the heating performance of the air conditioner 100 can be further improved. Further, for example, when the amount of the refrigerant circulating in the refrigerating cycle circuit 1 differs between the cooling operation and the heating operation, the air conditioner 100 may include a receiver for storing the surplus refrigerant in the refrigerating cycle circuit 1. .. The receivers are provided, for example, before and after the expansion valve 6.

1 refrigeration cycle circuit, 2 compressor, 3 flow path switching device, 4 flow path switching device, 5 flow path switching device, 6 expansion valve, 7 indoor heat exchanger, 10 1st outdoor heat exchanger, 11 1st refrigerant flow Road, 12 distributor, 13 merger, 20 second outdoor heat exchanger, 21 second refrigerant flow path, 31 outdoor blower, 32 indoor blower, 100 air conditioner, 110 outdoor unit, 120 indoor unit.

Claims

A refrigeration cycle circuit having a compressor, a plurality of flow path switching devices for switching the flow path of the refrigerant, a first outdoor heat exchanger, a second outdoor heat exchanger, an expansion valve and an indoor heat exchanger.
The compressor, the plurality of flow path switching devices, the first outdoor heat exchanger, the second outdoor heat exchanger, and the outdoor unit in which the expansion valve is housed.
The indoor unit in which the indoor heat exchanger is housed and
Equipped with
By switching the flow path of the refrigerant with the plurality of flow path switching devices,
During the cooling operation, the refrigerating cycle circuit has a configuration in which the refrigerant flows in the order of the compressor, the first outdoor heat exchanger, the second outdoor heat exchanger, the expansion valve, and the indoor heat exchanger. can be,
During the heating operation, the refrigerating cycle circuit has a configuration in which the refrigerant flows in the order of the compressor, the indoor heat exchanger, the second outdoor heat exchanger, the expansion valve, and the first outdoor heat exchanger. An air conditioner.
The first outdoor heat exchanger has a configuration in which a plurality of first refrigerant flow paths are formed in parallel.
The air conditioner according to claim 1, wherein the first outdoor heat exchanger includes a distributor that distributes a refrigerant to each of the first refrigerant flow paths during the heating operation.
The second outdoor heat exchanger has a configuration in which one second refrigerant flow path is formed, or a configuration in which a plurality of the second refrigerant flow paths are formed in parallel.
The air conditioner according to claim 2, wherein the number of the second refrigerant flow paths is smaller than the number of the first refrigerant flow paths.
An outdoor blower housed in the outdoor unit and supplying outside air to the first outdoor heat exchanger and the second outdoor heat exchanger is provided.
Any of claims 1 to 3 in which the second outdoor heat exchanger is arranged on the upstream side of the first outdoor heat exchanger in the direction of the flow of outside air generated when the outdoor blower rotates. The air conditioner described in item 1.