WO2021171401A1 - Air conditioning apparatus - Google Patents

Abstract

An air conditioning apparatus according to the present invention comprises: a coolant circuit in which a compressor, a heat source-side heat exchanger including a first heat source-side heat exchanger and a second heat source-side heat exchanger connected in parallel, a load-side throttle device, and a load-side heat exchanger are connected, and a non-azeotropic mixed coolant is circulated; first coolant piping and second coolant piping that divide the flow of coolant flowing out from the load-side throttle device during a heating operation and cause the coolant to circulate to the heat source-side heat exchanger; a first throttle device that reduces the pressure of coolant flowing into the first heat source-side heat exchanger through the first coolant piping during a heating operation; a second throttle device that reduces the pressure of coolant flowing into the second heat source-side heat exchanger through the second coolant piping during a heating operation; and a coolant-to-coolant heat exchanger that exchanges heat between a coolant circulating between the second throttle device and the second heat source-side heat exchanger and a coolant flowing into the first throttle device during a heating operation. The pressure loss of coolant circulating through the first heat source-side heat exchanger is greater than the pressure loss of coolant circulating through the second heat source-side heat exchanger.

Description

Air conditioner

The present disclosure relates to an air conditioner having a refrigerant circuit in which a non-azeotropic mixed refrigerant circulates.

In order to curb global warming, the refrigerant GWP (Global Warming Potential) is regulated by the Montreal Protocol and European F-gas regulations. Most of the refrigerants having a low GWP are non-azeotropic mixed refrigerants in which a plurality of types of refrigerants having different boiling points are mixed. In the non-azeotropic mixed refrigerant, the temperature is not constant from the start to the end of each process of the evaporation process and the condensation process, and a temperature gradient occurs. The temperature gradient acts in the direction in which the refrigerant temperature on the refrigerant inlet side of the evaporator becomes lower in the evaporation stroke. Therefore, in an air conditioner using a non-azeotropic mixed refrigerant, the refrigerant temperature at the refrigerant inlet of the evaporator drops to 0 ° C. or lower, and frost formation or freezing is likely to occur.

Conventionally, an air conditioner that suppresses frost formation of a non-azeotropic mixed refrigerant is known (see, for example, Patent Document 1). The air conditioner disclosed in Patent Document 1 is provided with a decompression means such as a capillary tube in the middle portion of the evaporator in order to raise the saturation temperature on the refrigerant inlet side of the evaporator and suppress frost formation. ..

Japanese Unexamined Patent Publication No. 60-140048

However, in the air conditioner disclosed in Patent Document 1, the temperature difference between the refrigerant and the air becomes small in the section from the refrigerant inlet of the evaporator to the decompression means, so that the heat exchange performance deteriorates.

The present disclosure has been made to solve the above-mentioned problems, and provides an air conditioner that suppresses a decrease in heat exchange performance of a heat source side heat exchanger that acts as an evaporator during heating operation. ..

The air conditioner according to the present disclosure includes a compressor, a heat source side heat exchanger including a first heat source side heat exchanger and a second heat source side heat exchanger connected in parallel, a load side throttle device, and a load side. A first refrigerant that is connected to a heat exchanger by a pipe and circulates a non-co-boiling mixed refrigerant, and a first refrigerant that divides the refrigerant flowing out from the load-side throttle device during heating operation and distributes it to the heat source-side heat exchanger. A pipe, a second refrigerant pipe, and a first throttle device provided in the first refrigerant pipe to reduce the pressure of the refrigerant flowing into the first heat source side heat exchanger via the first refrigerant pipe during the heating operation. A second throttle device provided in the second refrigerant pipe to reduce the pressure of the refrigerant flowing into the second heat source side heat exchanger through the second refrigerant pipe during the heating operation, and the second refrigerant pipe. It has a refrigerant that flows between the two drawing devices and the second heat source side heat exchanger, and a heat exchanger between refrigerants that exchanges heat between the refrigerant flowing into the first drawing device during the heating operation. In the first heat source side heat exchanger and the second heat source side heat exchanger, the pressure loss of the refrigerant flowing through the first heat source side heat exchanger is the pressure loss of the refrigerant flowing through the second heat source side heat exchanger. It is a larger configuration.

According to the present disclosure, the pressure of the refrigerant flowing into the first heat source side heat exchanger during the heating operation decreases according to the pressure loss in the first heat source side heat exchanger while maintaining a high temperature. Further, the refrigerant flowing into the second heat source side heat exchanger is overheated in the inter-refrigerant heat exchanger and the temperature rises. Therefore, it is possible to prevent the refrigerant temperature on the refrigerant inlet side of the heat source side heat exchanger from becoming low. Therefore, it is possible to suppress a decrease in heat exchange performance of the heat source side heat exchanger that acts as an evaporator during the heating operation.

It is a schematic diagram which shows one structural example of the refrigerant circuit of the air conditioner which concerns on Embodiment 1. FIG. It is a hardware configuration diagram which shows one configuration example of the control device shown in FIG. It is a hardware configuration diagram which shows another configuration example of the control device shown in FIG. FIG. 5 is a ph diagram for explaining the operation of the air conditioner according to the first embodiment during the heating operation. It is a schematic diagram which shows an example of the heat transfer tube provided in the 1st heat source side heat exchanger shown in FIG. It is a schematic diagram which shows an example of the heat transfer tube provided in the 2nd heat source side heat exchanger shown in FIG. It is a schematic diagram for comparing the flow path cross-sectional area of the plurality of heat transfer tubes shown in FIG. 5 with the flow path cross-sectional area of the heat transfer tube shown in FIG. It is a schematic diagram which shows one structural example of the refrigerant circuit of the air conditioner which concerns on Embodiment 2. FIG.

An embodiment of the air conditioner of the present disclosure will be described with reference to the drawings. Equivalent configurations are designated by the same reference numerals among a plurality of drawings, and once described, the description thereof will be appropriately omitted or simplified in another embodiment thereafter. Further, with respect to the configurations described in each figure, the shape, size, arrangement, etc. of the configurations are not limited to the cases shown in the drawings.

Embodiment 1.
The configuration of the air conditioner of the first embodiment will be described.
[Overall configuration of air conditioner]
FIG. 1 is a schematic view showing a configuration example of a refrigerant circuit of the air conditioner according to the first embodiment. The air conditioner 100 includes an outdoor unit 1 that generates a heat source, and indoor units 2a and 2b that utilize the heat source generated by the outdoor unit 1. In the first embodiment, the refrigerant that circulates between the outdoor unit 1 and the indoor units 2a and 2b is a non-azeotropic mixed refrigerant. The air conditioner 100 has a cooling operation mode and a heating operation mode as operation modes of the indoor units 2a and 2b.

The air conditioner 100 includes a liquid main pipe 3, two liquid branch pipes 5a and 5b branching from the liquid main pipe 3, and a gas as refrigerant pipes through which the refrigerant flows between the outdoor unit 1 and the indoor units 2a and 2b. It has a main pipe 4 and two gas branch pipes 6a and 6b branching from the gas main pipe 4. The outdoor unit 1 and the indoor unit 2a are connected by a liquid main pipe 3 and a liquid branch pipe 5a, and a gas main pipe 4 and a gas branch pipe 6a. The outdoor unit 1 and the indoor unit 2b are connected by a liquid main pipe 3 and a liquid branch pipe 5b, and a gas main pipe 4 and a gas branch pipe 6b.

[Outdoor unit]
The configuration of the outdoor unit 1 shown in FIG. 1 will be described. The outdoor unit 1 is installed, for example, outside the room. The outdoor unit 1 functions as a heat source unit that discharges or supplies heat for air conditioning. The outdoor unit 1 includes a compressor 10, a flow path switching device 11, a heat source side heat exchanger 12, an accumulator 13, a heat source side fan 17, and a control device 30. Further, the outdoor unit 1 includes a first throttle device 16, a second throttle device 15, an inter-refrigerant heat exchanger 14, a first refrigerant pipe 18a, and a second refrigerant pipe 18b. The heat source side heat exchanger 12 has a first heat source side heat exchanger 12a and a second heat source side heat exchanger 12b connected in parallel. Each of the compressor 10, the flow path switching device 11, the heat source side fan 17, the first throttle device 16, and the second throttle device 15 is connected to the control device 30 via a signal line (not shown).

The first refrigerant pipe 18a and the second refrigerant pipe 18b divide the refrigerant flowing into the heat source side heat exchanger 12. The first refrigerant pipe 18a circulates a part of the refrigerant flowing into the heat source side heat exchanger 12 to the first heat source side heat exchanger 12a. The second refrigerant pipe 18b circulates the remaining refrigerant among the refrigerants flowing into the heat source side heat exchanger 12 to the second heat source side heat exchanger 12b.

The first throttle device 16 is provided in the first refrigerant pipe 18a. The second throttle device 15 is provided in the second refrigerant pipe 18b. The inter-refrigerant heat exchanger 14 is provided in the middle of both the first refrigerant pipe 18a and the second refrigerant pipe 18b. The flow path to which the first heat source side heat exchanger 12a, the first throttle device 16 and the inter-refrigerant heat exchanger 14 are connected via the first refrigerant pipe 18a, and the second heat source side heat via the second refrigerant pipe 18b. The flow path to which the exchanger 12b, the inter-refrigerant heat exchanger 14 and the second throttle device 15 are connected is connected in parallel.

The compressor 10 sucks in the refrigerant in the low temperature and low pressure states, compresses the sucked refrigerant into the high temperature and high pressure states, and discharges the refrigerant. The compressor 10 is, for example, an inverter compressor whose capacity can be controlled. The heat source side fan 17 supplies outside air to the heat source side heat exchanger 12. The heat source side fan 17 is, for example, a propeller fan. The number of heat source side fans 17 is not limited to one, and may be a plurality of fans. The accumulator 13 is connected to the refrigerant suction port side of the compressor 10. The accumulator 13 prevents the liquid refrigerant from flowing into the compressor 10.

The flow path switching device 11 switches the flow direction of the refrigerant circulating in the refrigerant circuits 50a and 50b according to the operation modes of the heating operation mode and the cooling operation mode. The flow path switching device 11 circulates the refrigerant discharged from the compressor 10 to the load side heat exchangers 21a and 21b in the heating operation mode, and heats the refrigerant discharged from the compressor 10 to the heat source side heat in the cooling operation mode. It is distributed to the exchanger 12. The flow path switching device 11 is, for example, a four-way valve.

The first heat source side heat exchanger 12a and the second heat source side heat exchanger 12b exchange heat between the air supplied by the heat source side fan 17 and the refrigerant. The first heat source side heat exchanger 12a and the second heat source side heat exchanger 12b function as a condenser or a gas cooler in the cooling operation mode and as an evaporator in the heating operation mode. In the configuration example shown in FIG. 1, the second heat source side heat exchanger 12b is arranged on the wind side of the first heat source side heat exchanger 12a.

The first heat source side heat exchanger 12a has a configuration that causes a pressure loss of the refrigerant according to the temperature gradient of the non-azeotropic mixed refrigerant in order to suppress frost formation in the heating operation mode. The first heat source side heat exchanger 12a has a configuration in which, for example, the flow path cross-sectional area of the refrigerant is small so as to cause a large pressure loss of the refrigerant as compared with the second heat source side heat exchanger 12b. Further, the first heat source side heat exchanger 12a may have a longer flow path length of the heat transfer tube than the second heat source side heat exchanger 12b.

The first throttle device 16 and the second throttle device 15 are expansion valves that can control the opening degree. The first throttle device 16 and the second throttle device 15 are, for example, electronic expansion valves. The first throttle device 16 depressurizes the refrigerant flowing from the indoor units 2a and 2b into the first heat source side heat exchanger 12a via the first refrigerant pipe 18a in the heating operation mode. The second throttle device 15 depressurizes the refrigerant flowing from the indoor units 2a and 2b into the second heat source side heat exchanger 12b via the second refrigerant pipe 18b in the heating operation mode. The first throttle device 16 and the second throttle device 15 are fully opened in the cooling operation mode.

The inter-refrigerant heat exchanger 14 includes a refrigerant that flows between the second throttle device 15 and the second heat source side heat exchanger 12b in the second refrigerant pipe 18b, and a refrigerant that flows into the first throttle device 16 during the heating operation. To exchange heat. The inter-refrigerant heat exchanger 14 is, for example, a double tube heat exchanger, a plate heat exchanger or a shell and tube heat exchanger. The configuration of the control device 30 will be described after the description of the configurations of the indoor units 2a and 2b.

[Indoor unit]
The configurations of the indoor units 2a and 2b shown in FIG. 1 will be described. Each of the indoor units 2a and 2b is installed, for example, in a room inside the room. The indoor unit 2a supplies conditioned air to the room in which the indoor unit 2a is installed. The indoor unit 2b supplies conditioned air to the room in which the indoor unit 2b is installed. The indoor unit 2a includes a load-side throttle device 20a, a load-side heat exchanger 21a, a load-side fan 22a, and a room temperature sensor 23a. The indoor unit 2b includes a load-side throttle device 20b, a load-side heat exchanger 21b, a load-side fan 22b, and a room temperature sensor 23b. Refrigerant leakage detectors (not shown) may be provided in the indoor units 2a and 2b.

The load- side throttle devices 20a and 20b, the load- side fans 22a and 22b, and the room temperature sensors 23a and 23b are connected to the control device 30 via signal lines not shown in the figure, respectively. The room temperature sensor 23a detects the room temperature of the room in which the indoor unit 2a is installed, and outputs the detected room temperature data to the control device 30. The room temperature sensor 23b detects the room temperature of the room in which the indoor unit 2b is installed, and outputs the detected room temperature data to the control device 30.

The load-side fan 22a sucks air from the room in which the indoor unit 2a is installed, and supplies the sucked air to the load-side heat exchanger 21a. The load-side fan 22b sucks air from the room in which the indoor unit 2b is installed, and supplies the sucked air to the load-side heat exchanger 21b. The load- side fans 22a and 22b are, for example, cross-flow fans.

The load- side throttle devices 20a and 20b function as a pressure reducing valve or an expansion valve that depressurizes and expands the refrigerant. The load- side throttle devices 20a and 20b are, for example, electronic expansion valves whose opening degree can be changed. The load-side throttle device 20a is located on the upstream side of the load-side heat exchanger 21a in the flow direction of the refrigerant when the indoor unit 2a operates in the cooling operation mode. The load-side throttle device 20b is located on the upstream side of the load-side heat exchanger 21b in the flow direction of the refrigerant when the indoor unit 2b operates in the cooling operation mode.

The load-side heat exchanger 21a is connected to the flow path switching device 11 of the outdoor unit 1 via the gas branch pipe 6a and the gas main pipe 4, and is connected to the flow path switching device 11 of the outdoor unit 1 via the load-side throttle device 20a, the liquid branch pipe 5a, and the liquid main pipe 3. It is connected to the first refrigerant pipe 18a and the second refrigerant pipe 18b of the outdoor unit 1. The load-side heat exchanger 21b is connected to the flow path switching device 11 of the outdoor unit 1 via the gas branch pipe 6b and the gas main pipe 4, and is connected to the flow path switching device 11 of the outdoor unit 1 via the load-side throttle device 20b, the liquid branch pipe 5b, and the liquid main pipe 3. It is connected to the first refrigerant pipe 18a and the second refrigerant pipe 18b of the outdoor unit 1.

The load side heat exchangers 21a and 21b function as an evaporator in the cooling operation mode and as a condenser in the heating operation mode. The load-side heat exchanger 21a generates heating air or cooling air to be supplied to the room by exchanging heat between the air supplied by the load-side fan 22a and the refrigerant. The load-side heat exchanger 21b generates heating air or cooling air to be supplied to the room by exchanging heat between the air supplied by the load-side fan 22b and the refrigerant.

The compressor 10, the heat source side heat exchanger 12, the load side throttle device 20a, and the load side heat exchanger 21a are connected by a refrigerant pipe to form a refrigerant circuit 50a in which the refrigerant circulates. The compressor 10, the heat source side heat exchanger 12, the load side throttle device 20b, and the load side heat exchanger 21b are connected by a refrigerant pipe to form a refrigerant circuit 50b in which the refrigerant circulates. In the first embodiment, each of the refrigerant circuits 50a and 50b includes a first throttle device 16, a second throttle device 15, and an inter-refrigerant heat exchanger 14, as shown in FIG.

Although FIG. 1 shows a configuration in which two indoor units 2a and 2b are connected in parallel to the outdoor unit 1, one indoor unit may be connected to the outdoor unit 1. It may be more than one. Further, FIG. 1 shows a case where the load-side throttle device 20a is provided in the indoor unit 2a and the load-side throttle device 20b is provided in the indoor unit 2b. If the first throttle device 16 and the second throttle device 15 serve as the load- side throttle devices 20a and 20b, the indoor units 2a and 2b may not be provided with the diaphragm devices. When there is one indoor unit, the indoor unit may not be provided with the diaphragm device, and the outdoor unit may be provided with the diaphragm device. Further, although FIG. 1 shows a configuration in which the flow path switching device 11 is provided in the outdoor unit 1, the configuration may be such that the flow path switching device 11 is not provided, such as a dedicated heating machine. .. Further, the sensors provided in the air conditioner 100 are not limited to the room temperature sensors 23a and 23b, and sensors not shown in the figure may be provided.

Next, the configuration of the control device 30 shown in FIG. 1 will be described. The control device 30 controls the entire air conditioner 100. The control device 30 controls the refrigerating cycle of the refrigerant circulating in the refrigerant circuits 50a and 50b, based on the detected values of various sensors such as the room temperature sensors 23a and 23b and the set temperature Tset.

The operation mode and the set temperature Tset1 are input to the control device 30 by the user of the indoor unit 2a via a remote controller (not shown in the figure). The operation mode and the set temperature Tset2 are input to the control device 30 by the user of the indoor unit 2b via a remote controller (not shown). In the first embodiment, the operation mode selected by the user of the indoor unit 2a and the operation mode selected by the user of the indoor unit 2b are the same.

The control device 30 controls the flow path switching device 11 so that the flow direction of the refrigerant flowing through the refrigerant circuits 50a and 50b is switched according to the operation mode selected by the user of the indoor units 2a and 2b. Specifically, when the operation mode is the heating operation mode, the control device 30 controls the flow path switching device 11 so that the refrigerant discharged from the compressor 10 flows to the load side heat exchangers 21a and 21b. When the operation mode is the cooling operation mode, the control device 30 controls the flow path switching device 11 so that the refrigerant discharged from the compressor 10 flows to the heat source side heat exchanger 12.

When the operation mode is the cooling operation mode, the control device 30 controls the opening degree of the first throttle device 16 and the second throttle device 15 to the fully open state. Further, in the cooling operation mode, the control device 30 controls each of the indoor units 2a and 2b as follows. The control device 30 has the drive rotation speed of the compressor 10, the rotation speed of the heat source side fan 17, the rotation speed of the load side fan 22a, and the load side throttle device 20a so that the detected value of the room temperature sensor 23a matches the set temperature Tset1. Control the opening of. The control device 30 has the drive rotation speed of the compressor 10, the rotation speed of the heat source side fan 17, the rotation speed of the load side fan 22b, and the load side throttle device 20b so that the detected value of the room temperature sensor 23b matches the set temperature Tset2. Control the opening of.

When the operation mode is the heating operation mode, the control device 30 minimizes the depressurization so as not to interfere with the heat exchange performed by the inter-refrigerant heat exchanger 14 for the purpose of adjusting the flow rates of the load side heat exchangers 21a and 21b. The opening degrees of the load side throttle devices 20a and 20b are controlled so as to be. For example, the control device 30 sets the opening degrees of the load- side throttle devices 20a and 20b to the fully open state. Further, in the heating operation mode, the control device 30 controls each of the indoor units 2a and 2b as follows. In the control device 30, the drive rotation speed of the compressor 10, the rotation speed of the heat source side fan 17, the rotation speed of the load side fan 22a, and the first The opening degree of the drawing device 16 and the second drawing device 15 is controlled. In the control device 30, the drive rotation speed of the compressor 10, the rotation speed of the heat source side fan 17, the rotation speed of the load side fan 22b, and the first The opening degree of the drawing device 16 and the second drawing device 15 is controlled.

Further, in the heating operation mode, the control device 30 adjusts the flow rate of the refrigerant flowing to the first heat source side heat exchanger 12a by controlling the opening ratio Rv of the first throttle device 16 and the second throttle device 15. The pressure loss of the refrigerant in the first heat source side heat exchanger 12a may be controlled. The control device 30 controls the pressure loss of the first heat source side heat exchanger 12a in response to the cooling and heating loads of the air conditioner 100. For example, in the heating operation mode, the control device 30 is opened so that the pressure loss of the first heat source side heat exchanger 12a becomes small in the case of low load operation where there is no concern about frost formation or operation at a high outside air temperature. The degree ratio Rv is controlled. In the heating operation mode, the control device 30 has an opening ratio so that the pressure loss of the first heat source side heat exchanger 12a becomes large in the case of high load operation in which there is a large concern about frost formation or operation at a low outside air temperature. Control Rv.

The opening ratio Rv is the opening ratio Rvl in the case of low load operation or operation at a high outside air temperature where there is no concern about frost formation, and the case of high load operation or operation at a low outside air temperature where there is a large concern about frost formation. The opening ratio Rvh may be predetermined. Further, a refrigerant temperature sensor (not shown) is provided on the refrigerant outlet side in the heating operation mode of the first heat source side heat exchanger 12a, and the control device 30 sets the detection value of the refrigerant temperature sensor to a predetermined target temperature Temp. The opening ratio Rv may be controlled so as to be.

The control device 30 is composed of, for example, an analog circuit, a digital circuit, or a circuit in which these circuits are combined. The control device 30 is composed of hardware such as a circuit device that realizes various functions. Further, the control device 30 may have a configuration in which various functions are realized by executing software by an arithmetic unit such as a microcomputer.

An example of the hardware of the control device 30 shown in FIG. 1 will be described. FIG. 2 is a hardware configuration diagram showing a configuration example of the control device shown in FIG. When the function of the control device 30 is executed by hardware, the control device 30 is composed of a processing circuit 80 as shown in FIG.

When the function of the control device 30 is executed by hardware, the processing circuit 80 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field). -Programmable Gate Array), or a combination of these.

Another configuration example of the hardware of the control device 30 shown in FIG. 1 will be described. FIG. 3 is a hardware configuration diagram showing another configuration example of the control device shown in FIG. When the function of the control device 30 is executed by software, the control device 30 shown in FIG. 1 is composed of a processor 81 such as a CPU (Central Processing Unit) and a memory 82 as shown in FIG. The function of the control device 30 is realized by the processor 81 and the memory 82. FIG. 3 shows that the processor 81 and the memory 82 are communicably connected to each other.

When the function of the control device 30 is executed by software, the function of the control device 30 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as a program and stored in the memory 82. The processor 81 realizes the function of the control device 30 by reading and executing the program stored in the memory 82. The memory 82 may store the above-mentioned opening ratios Rvh and Rvr and the target temperature Temp.

As the memory 82, for example, a non-volatile semiconductor memory such as a ROM (Read Only Memory), a flash memory, an EPROM (Erasable and Programmable ROM), and an EPROM (Electrically Erasable and Programmable ROM) is used. Further, as the memory 82, a volatile semiconductor memory of RAM (Random Access Memory) may be used. Further, as the memory 82, a removable recording medium such as a magnetic disk, a flexible disk, an optical disk, a CD (Compact Disc), an MD (Mini Disc), and a DVD (Digital Versaille Disc) may be used.

Although FIG. 1 illustrates a case where the control device 30 is provided in the outdoor unit 1, the control device may be provided in the outdoor unit 1 and the indoor units 2a and 2b, respectively. It may be provided in at least one of the indoor units 2a and 2b. When a plurality of control devices are provided in the air conditioner 100, the plurality of control devices are communicated with each other to perform the functions of the control device 30 described above.

[Operation mode of air conditioner]
Next, each operation mode executed by the air conditioner 100 will be described. The air conditioner 100 executes the cooling operation and the heating operation of the indoor units 2a and 2b based on the instructions input from the user via the remote controller (not shown) for each of the indoor units 2a and 2b. As described above, the operation modes executed by the air conditioner 100 of FIG. 1 include a cooling operation mode in which all of the operating indoor units 2a and 2b perform cooling operation and a heating operation in which both the operating indoor units 2a and 2b perform heating operation. There is a heating operation mode to perform. The flow of the refrigerant in each operation mode will be described below.

[Cooling operation mode]
The flow of the refrigerant in the cooling operation mode will be described with reference to FIG. In FIG. 1, the flow direction of the refrigerant flowing through the refrigerant circuits 50a and 50b in the cooling operation mode is indicated by a broken line arrow.

The compressor 10 sucks in low-temperature and low-pressure refrigerant, compresses the sucked refrigerant, and discharges high-temperature and high-pressure refrigerant. The high-temperature and high-pressure refrigerant discharged from the compressor 10 is diverted to the first heat source side heat exchanger 12a and the second heat source side heat exchanger 12b via the flow path switching device 11. Then, the refrigerant flowing into the second heat source side heat exchanger 12b and the first heat source side heat exchanger 12a exchanges heat with the outside air supplied by the heat source side fan 17 and condenses. The refrigerant condensed in the first heat source side heat exchanger 12a and the second heat source side heat exchanger 12b flows out from the outdoor unit 1 and passes through the liquid main pipe 3 and the liquid branch pipes 5a and 5b to the indoor unit 2a. And flow into 2b. At this time, the first drawing device 16 and the second drawing device 15 are in a fully open state so as not to obstruct the flow of the refrigerant.

The refrigerant flowing into the indoor unit 2a is expanded by the load side throttle device 20a. The refrigerant expanded by the load-side throttle device 20a flows into the load-side heat exchanger 21a that acts as an evaporator, absorbs heat from the room air, and evaporates. In the load side heat exchanger 21a, the indoor air is cooled by the refrigerant absorbing heat from the indoor air. Further, the refrigerant flowing into the indoor unit 2b is expanded by the load side throttle device 20b. The refrigerant expanded by the load-side throttle device 20b flows into the load-side heat exchanger 21b that acts as an evaporator, absorbs heat from the room air, and evaporates. In the load side heat exchanger 21b, the indoor air is cooled by the refrigerant absorbing heat from the indoor air. The refrigerant flowing out of the load- side heat exchangers 21a and 21b returns to the outdoor unit 1 via the gas branch pipes 6a and 6b and the gas main pipe 4. The refrigerant that has flowed into the outdoor unit 1 is sucked into the compressor 10 via the flow path switching device 11 and is compressed again.

From the viewpoint of saving refrigerant, the refrigerant may be expanded by the first throttle device 16 and the second throttle device 15 instead of the load side throttle devices 20a and 20b. In this case, the amount of refrigerant that occupies the liquid main pipe 3 can be reduced.

[Heating operation mode]
The flow of the refrigerant in the heating operation mode will be described with reference to FIG. In FIG. 1, the flow direction of the refrigerant flowing through the refrigerant circuits 50a and 50b in the heating operation mode is indicated by a solid arrow.

The compressor 10 sucks in low-temperature and low-pressure refrigerant, compresses the sucked refrigerant, and discharges high-temperature and high-pressure refrigerant. The high-temperature and high-pressure refrigerant discharged from the compressor 10 flows out from the outdoor unit 1 via the flow path switching device 11. The high-temperature and high-pressure refrigerant flowing out of the outdoor unit 1 is diverted to the load- side heat exchangers 21a and 21b via the gas main pipe 4 and the gas branch pipes 6a and 6b.

The refrigerant flowing into the load side heat exchanger 21a is condensed while heating the indoor space by dissipating heat to the indoor air in the load side heat exchanger 21a. The refrigerant condensed in the load side heat exchanger 21a is slightly expanded in the load side drawing device 20a. Further, the refrigerant flowing into the load side heat exchanger 21b is condensed while heating the indoor space by dissipating heat to the indoor air in the load side heat exchanger 21b. The refrigerant condensed in the load side heat exchanger 21b is slightly expanded by the load side drawing device 20b. The refrigerant flowing out of the load- side throttle devices 20a and 20b returns to the outdoor unit 1 via the liquid branch pipes 5a and 5b and the liquid main pipe 3.

Here, the load- side throttle devices 20a and 20b function as flow rate adjustments for the load- side heat exchangers 21a and 21b, but are set so that decompression is minimized. The refrigerant that has flowed into the outdoor unit 1 is divided into the first refrigerant pipe 18a and the second refrigerant pipe 18b.

The refrigerant that has flowed into the second refrigerant pipe 18b is expanded to a low pressure by the second throttle device 15, and then partly evaporates in the inter-refrigerant heat exchanger 14. The refrigerant flowing out of the inter-refrigerant heat exchanger 14 flows into the second heat source side heat exchanger 12b. On the other hand, the refrigerant flowing into the first refrigerant pipe 18a is overcooled in the inter-refrigerant heat exchanger 14 in a high pressure state, expanded to a low pressure in the first throttle device 16, and then the first heat source side heat exchanger. It flows into 12a. The refrigerant evaporated in the second heat source side heat exchanger 12b and the first heat source side heat exchanger 12a is sucked into the compressor 10 via the flow path switching device 11 and compressed again.

The operation of the air conditioner 100 of the first embodiment in the heating operation mode will be described. FIG. 4 is a ph diagram for explaining the operation of the air conditioner according to the first embodiment during the heating operation. The horizontal axis of FIG. 4 is the specific enthalpy h, and the vertical axis is the pressure p.

Further, in FIG. 4, the sloping broken line shown in the wet steam region indicates the isotherm of the non-azeotropic mixed refrigerant. The isotherms of the non-azeotropic mixed refrigerant indicate that there is a temperature gradient. The relationship between the temperatures T1, T2 and T3 shown in FIG. 4 is T1> T2> T3. T2> 0 ° C. The relationship between the pressures p1 and p2 is p2> p1. Step K1 shows a process in which the refrigerant flowing through the second drawing device 15 is depressurized and expanded. Step K2 shows a process in which the refrigerant flowing through the first drawing device 16 is depressurized and expanded.

As shown in FIG. 4, the refrigerant flowing into the second refrigerant pipe 18b is depressurized to the pressure p1 by the second throttle device 15, and then a part of the refrigerant evaporates in the inter-refrigerant heat exchanger 14 shown in the section RR. And overheated. The refrigerant flowing out of the inter-refrigerant heat exchanger 14 flows into the second heat source side heat exchanger 12b while maintaining the pressure p1. The temperature of the refrigerant is higher than the temperature T2 when flowing into the second heat source side heat exchanger 12b. That is, the temperature of the refrigerant is higher than 0 ° C. at the refrigerant inlet of the second heat source side heat exchanger 12b.

On the other hand, the refrigerant flowing into the first refrigerant pipe 18a is supercooled in the inter-refrigerant heat exchanger 14 shown in the section RR while maintaining the high pressure state. After that, the refrigerant flowing out of the inter-refrigerant heat exchanger 14 is reduced to the pressure p2 in the first throttle device 16 and then flows into the first heat source side heat exchanger 12a. The temperature of the refrigerant is T1 which is higher than the temperature T2 when flowing into the first heat source side heat exchanger 12a. The pressure p of the refrigerant flowing through the first heat source side heat exchanger 12a gradually decreases due to the pressure loss in the first heat source side heat exchanger 12a. The change in pressure p at this time corresponds to the temperature gradient of the isotherm of the temperature T1 of the non-azeotropic mixed refrigerant. The refrigerant flowing through the first heat source side heat exchanger 12a flows through the first heat source side heat exchanger 12a while maintaining the temperature T1 from the refrigerant inlet to the refrigerant outlet of the first heat source side heat exchanger 12a, and at the refrigerant outlet. The pressure drops to p1.

As described above, in the heating operation mode, the pressure of the refrigerant flowing into the first heat source side heat exchanger 12a decreases according to the pressure loss in the first heat source side heat exchanger 12a while maintaining a high temperature. Further, the refrigerant flowing into the second heat source side heat exchanger is overheated in the inter-refrigerant heat exchanger and the temperature rises. Therefore, it is possible to prevent the refrigerant temperature on the refrigerant inlet side of the heat source side heat exchanger 12 from becoming low. As a result, frost formation and freezing can be prevented, and deterioration of the heat exchange performance of the heat source side heat exchanger acting as an evaporator during the heating operation can be suppressed.

As shown in FIG. 4, it is desirable that the pressure loss of the refrigerant generated in the first heat source side heat exchanger 12a is set to a size along the isotherm in the evaporation process of the non-azeotropic mixed refrigerant. The pressure change of the refrigerant due to the pressure loss does not have to completely coincide with the isotherm in the evaporation process of the non-azeotropic mixed refrigerant. Further, the pressure loss of the refrigerant generated in the second heat source side heat exchanger 12b is preferably as small as possible in order to increase the temperature difference between the refrigerant and the air and improve the heat exchange performance. Therefore, the pressure loss of the first heat source side heat exchanger 12a is configured to be larger than the pressure loss of the second heat source side heat exchanger 12b.

As a configuration for making the pressure loss of the first heat source side heat exchanger 12a larger than the pressure loss of the second heat source side heat exchanger 12b, by reducing the diameter of the cross section of the heat transfer tube, the flow path cross-sectional area of the refrigerant is reduced. Can be considered to be smaller. For example, the flow path cross-sectional area of the first heat source side heat exchanger 12a is made smaller than the flow path cross-sectional area of the second heat source side heat exchanger 12b. By reducing the flow path cross-sectional area of the first heat source side heat exchanger 12a, the pressure loss of the first heat source side heat exchanger 12a becomes large.

When a plurality of heat transfer tubes are provided in parallel in each of the heat exchangers 12a on the first heat source side and the heat exchanger 12b on the second heat source side, the number of heat transfer tubes in the first heat source side heat exchanger 12a is increased. The number should be less than the number of heat transfer tubes of the second heat source side heat exchanger 12b. With this configuration, the first heat source side heat exchanger 12a is smaller than the second heat source side heat exchanger 12b in terms of the total area of the flow paths of the plurality of heat transfer tubes. As a case where a plurality of heat transfer tubes are provided in parallel, for example, there is a flat tube.

Further, as a configuration for making the pressure loss of the first heat source side heat exchanger 12a larger than the pressure loss of the second heat source side heat exchanger 12b, the heat transfer area of the first heat source side heat exchanger 12a is set to the second heat source. It is conceivable to make it larger than the heat transfer area of the side heat exchanger 12b. By increasing the heat transfer area of the first heat source side heat exchanger 12a, the amount of heat exchange of the first heat source side heat exchanger 12a increases. By increasing the flow rate of the refrigerant on the side of the first heat source side heat exchanger 12a having a large amount of heat exchange, the pressure loss of the first heat source side heat exchanger 12a becomes large. For example, by making the flow path length of the heat transfer tube of the first heat source side heat exchanger 12a longer than the flow path length of the heat transfer tube of the second heat source side heat exchanger 12b, the heat transfer of the first heat source side heat exchanger 12a is performed. The heat area becomes larger than the heat transfer area of the second heat source side heat exchanger 12b. In this case, the pressure loss of the first heat source side heat exchanger 12a is larger than the pressure loss of the second heat source side heat exchanger 12b.

Further, the flow path cross-sectional area of the first heat source side heat exchanger 12a may be configured to increase from the refrigerant inlet side toward the refrigerant outlet side in the heating operation mode. With this configuration, in the heating operation mode, the dryness increases on the downstream side of the refrigerant as the refrigerant evaporates, preventing the pressure loss from becoming excessive and maintaining a constant pressure loss along the flow direction of the refrigerant. be able to. Further, in the cooling operation mode, the flow path cross-sectional area becomes smaller on the downstream side of the refrigerant as the refrigerant condenses, which has the effect of suppressing a decrease in the heat transfer coefficient.

Further, the first heat source side heat exchanger 12a and the second heat source side heat exchanger 12b may be arranged side by side in the vertical direction, one heat exchanger is arranged on the wind side and the other heat exchanger is arranged on the leeward side. May be placed in. As shown in FIG. 1, when the first heat source side heat exchanger 12a is arranged on the leeward side and the second heat source side heat exchanger 12b is arranged on the windward side, the effect of suppressing frost formation is expected to be improved. can. More specifically, the second heat source side heat exchanger 12b is more likely to be frosted than the first heat source side heat exchanger 12a because the refrigerant temperature at the refrigerant inlet is lowered due to the temperature gradient. By arranging the second heat source side heat exchanger 12b on the wind side where the air temperature is high, the surface temperature of the pipe becomes high, the frost resistance is improved, and frost formation becomes difficult.

Further, the control device 30 controls the opening ratio Rv of the first drawing device 16 and the second drawing device 15 to adjust the flow rate of the refrigerant flowing through the first heat source side heat exchanger 12a, and to adjust the flow rate of the refrigerant flowing to the first heat source side heat exchanger 12a. The pressure loss of the refrigerant in the exchanger 12a may be controlled. For example, the control device 30 has an opening ratio Rvl in the case of low load operation or operation at a high outside air temperature where there is no concern about frost formation, and in the case of high load operation or operation at a low outside air temperature where there is a large concern about frost formation. The opening ratio Rvh of the above may be set to a different value.

Here, a configuration example of a heat transfer tube provided in the heat source side heat exchanger 12 shown in FIG. 1 will be described. FIG. 5 is a schematic view showing an example of a heat transfer tube provided in the first heat source side heat exchanger shown in FIG. FIG. 5 shows a case where the heat transfer tube provided in the first heat source side heat exchanger 12a is a flat tube 61 in which a plurality of heat transfer tubes 61a are arranged in parallel with the flow path. FIG. 5 shows a case where the number of heat transfer tubes 61a of the flat tube 61 is seven. FIG. 5 shows the cross-sectional shape of the flat tube 61, and the diameter of each heat transfer tube 61a is D. The plurality of heat transfer tubes 61a extend in the direction perpendicular to the surface of the plate-shaped heat radiation fin 71 (in the direction of the Y-axis arrow).

Assuming that the flow path cross-sectional area of the flat tube 61 shown in FIG. 5 is SA1, the flow path cross-sectional area SA1 is represented by the total cross-sectional area of the seven heat transfer tubes 61a. That is, it is expressed by the equation of SA1 = 7 × π × (D / 2) ² = (7/4) πD ^2. Assuming that the heat transfer area of the flat tube 61 shown in FIG. 5 is HTA1, when the flow path length is L, HTA1 = (total circumference of the seven heat transfer tubes 61a) × flow path length L = 7 × (π) It is expressed by the formula of × D) × L = 7πDL.

FIG. 6 is a schematic view showing an example of a heat transfer tube provided in the second heat source side heat exchanger shown in FIG. FIG. 6 shows a case where the heat transfer tube 62 provided in the second heat source side heat exchanger 12b is a single circular tube. FIG. 6 shows the cross-sectional shape of the heat transfer tube 62, and the diameter of the heat transfer tube 62 is 3 × D. That is, the diameter of the heat transfer tube 62 is three times as long as the diameter of the heat transfer tube 61a shown in FIG. The heat transfer tube 62 extends in the direction perpendicular to the surface of the plate-shaped heat radiation fin 72 (in the direction of the Y-axis arrow).

Assuming that the flow path cross-sectional area of the heat transfer tube 62 shown in FIG. 6 is SA2, the flow path cross-sectional area SA2 is expressed by the equation of ^{SA2 = π × (3 × D / 2) 2} = (9/4) πD ^2. NS. Assuming that the heat transfer area of the heat transfer tube 62 shown in FIG. 6 is HTA2, when the flow path length is L, HTA2 = (circumference of the heat transfer tube 62) × flow path length L = π × (3 × D) × L It is expressed by the formula of = 3πDL.

FIG. 7 is a schematic diagram for comparing the flow path cross-sectional area of the plurality of heat transfer tubes shown in FIG. 5 with the flow path cross-sectional area of the heat transfer tube shown in FIG. FIG. 7 shows the seven heat transfer tubes 61a in order to make it easier to compare the flow path cross-sectional area of the seven heat transfer tubes 61a shown in FIG. 5 with the flow path cross-sectional area of the heat transfer tubes 62 shown in FIG. The bundled and bundled seven heat transfer tubes 61a are displayed so as to overlap with the heat transfer tubes 62.

With reference to FIG. 7, it can be seen that the flow path cross-sectional area of the seven heat transfer tubes 61a is smaller than the flow path cross-sectional area of the heat transfer tubes 62. It is clear that the relationship of SA1 <SA2 is obtained even when the two equations of SA1 = (7/4) πD ² and SA2 = (9/4) πD ^{2 are compared.} The flow path cross-sectional area of the flat tube 61 shown in FIG. 5 is smaller than the flow path cross-sectional area of the heat transfer tube 62 shown in FIG.

Next, let's compare the heat transfer area of the seven heat transfer tubes 61a shown in FIG. 5 with the heat transfer area of the heat transfer tube 62 shown in FIG. The heat transfer area HTA1 of the seven heat transfer tubes 61a is HTA1 = 7πDL, and the heat transfer area HTA2 of the heat transfer tubes 62 is HTA2 = 3πDL. Therefore, the relationship is HTA1> HTA2. The heat transfer area of the flat tube 61 shown in FIG. 5 is larger than the heat transfer area of the heat transfer tube 62 shown in FIG.

The heat radiation fin 71 shown in FIG. 5 shows a part cut out from the actual heat radiation fin along the periphery of the flat tube 61 for convenience of explanation, and FIG. 5 does not show the entire shape of the heat radiation fin 71. .. Like the heat radiating fins 71 shown in FIG. 5, the heat radiating fins 72 shown in FIG. 6 do not show the overall shape of the heat radiating fins 72. Further, although FIG. 5 shows a case where the number of heat transfer tubes 61a is 7, the number of heat transfer tubes 61a used for the flat tube 61 is not limited to 7.

In the air conditioner 100 of the first embodiment, the compressor 10, the heat source side heat exchanger 12, the load side throttle devices 20a and 20b, and the load side heat exchangers 21a and 21b are connected by piping and are not connected. It has refrigerant circuits 50a and 50b through which the conditioned mixed refrigerant circulates. The heat source side heat exchanger 12 has a first heat source side heat exchanger 12a and a second heat source side heat exchanger 12b connected in parallel. The air conditioner 100 includes a first refrigerant pipe 18a and a second refrigerant pipe 18b that divide the refrigerant flowing out from the load side throttle devices 20a and 20b during the heating operation and distribute the refrigerant to the heat source side heat exchanger 12, and a first throttle device. It has 16, a second drawing device 15, and a refrigerant heat exchanger 14. The first throttle device 16 depressurizes the refrigerant flowing into the first heat source side heat exchanger 12a via the first refrigerant pipe 18a during the heating operation. The second throttle device 15 depressurizes the refrigerant flowing into the second heat source side heat exchanger 12b via the second refrigerant pipe 18b during the heating operation. The inter-refrigerant heat exchanger 14 includes a refrigerant that flows between the second throttle device 15 and the second heat source side heat exchanger 12b in the second refrigerant pipe 18b, and a refrigerant that flows into the first throttle device 16 during the heating operation. To exchange heat. In the first heat source side heat exchanger 12a and the second heat source side heat exchanger 12b, the pressure loss of the refrigerant flowing through the first heat source side heat exchanger 12a is the pressure loss of the refrigerant flowing through the second heat source side heat exchanger 12b. It is a larger configuration.

According to the first embodiment, in the heating operation mode, the refrigerant flowing into the first heat source side heat exchanger 12a has a pressure according to the pressure loss in the first heat source side heat exchanger 12a while maintaining a high temperature. Decreases. Further, the refrigerant flowing into the second heat source side heat exchanger 12b is overheated in the inter-refrigerant heat exchanger 14 and the temperature rises. Therefore, it is possible to prevent the refrigerant temperature on the refrigerant inlet side of the heat source side heat exchanger 12 from becoming low. As a result, during the heating operation, frost formation and freezing in the heat source side heat exchanger 12 can be prevented, and deterioration of the heat exchange performance of the heat source side heat exchanger 12 acting as an evaporator can be suppressed.

Embodiment 2.
The air conditioner of the second embodiment effectively utilizes the inter-refrigerant heat exchanger 14 shown in FIG. 1 in the cooling operation mode. In the second embodiment, the same reference numerals are given to the configurations described in the first embodiment, and detailed description thereof will be omitted. Further, in the second embodiment, the points different from the configuration described in the first embodiment will be described in detail, and the description of the same configuration will be omitted.

The configuration of the air conditioner of the second embodiment will be described. FIG. 8 is a schematic view showing a configuration example of a refrigerant circuit of the air conditioner according to the second embodiment. The air conditioner 101 shown in FIG. 8 has a different configuration of the outdoor unit as compared with the air conditioner 100 shown in FIG. In addition to the configuration of the outdoor unit 1 shown in FIG. 1, the outdoor unit 1a of the air conditioner 101 includes a third refrigerant pipe 19, a first on-off valve 41, a second on-off valve 42, a third on-off valve 43, and an injection. It has a pipe 44.

The first on-off valve 41 is provided in the first refrigerant pipe 18a. Specifically, the first on-off valve 41 includes a confluence point MP between the first refrigerant pipe 18a, the second refrigerant pipe 18b, and the pipes connected to the load- side throttle devices 20a and 20b, and a heat exchanger between the refrigerants. It is provided between 14 and 14. The third refrigerant pipe 19 is used between the first heat source side heat exchanger 12a and the first throttle device 16 in the first refrigerant pipe 18a, and between the second heat source side heat exchanger 12b and the refrigerant in the second refrigerant pipe 18b. Connect between the vessels 14. The second on-off valve 42 is provided in the third refrigerant pipe 19. The injection pipe 44 branches from between the refrigerant heat exchanger 14 and the first on-off valve 41 and is connected to the suction side of the compressor 10. The third on-off valve 43 is provided in the injection pipe 44.

The first on-off valve 41, the second on-off valve 42, and the third on-off valve 43 are, for example, solenoid valves. Each of the first on-off valve 41, the second on-off valve 42, and the third on-off valve 43 is connected to the control device 30 via a signal line (not shown). When the operation mode of the indoor units 2a and 2b is the heating operation mode, the control device 30 opens the first on-off valve 41 and closes the second on-off valve 42 and the third on-off valve 43. When the operation mode of the indoor units 2a and 2b is the cooling operation mode, the control device 30 closes the first on-off valve 41 and opens the second on-off valve 42 and the third on-off valve 43.

The operation of the air conditioner 101 of the second embodiment will be described. In FIG. 8, the flow direction of the refrigerant flowing through the refrigerant circuits 50a and 50b is indicated by a solid arrow in the heating operation mode, and the flow direction of the refrigerant flowing through the refrigerant circuits 50a and 50b is indicated by a broken arrow in the cooling operation mode. Shown.

In the heating operation mode, the first on-off valve 41 is in the open state, and the second on-off valve 42 and the third on-off valve 43 are in the closed state. Since the flow of the refrigerant in the heating operation mode is the same as that described in the first embodiment, the detailed description thereof will be omitted in the second embodiment.

In the second embodiment, the flow of the refrigerant in the cooling operation mode will be described with reference to FIG. In the cooling operation mode, the first on-off valve 41 is in the closed state, and the second on-off valve 42 and the third on-off valve 43 are in the open state.

The refrigerant flowing out of the compressor 10 is diverted to the first refrigerant pipe 18a and the second refrigerant pipe 18b via the flow path switching device 11. The refrigerant that has flowed into the second refrigerant pipe 18b condenses in the second heat source side heat exchanger 12b, and then flows into the inter-refrigerant heat exchanger 14. The refrigerant flowing into the first refrigerant pipe 18a is condensed in the first heat source side heat exchanger 12a, then a part of the refrigerant flows into the first throttle device 16, and the remaining refrigerant remains in a high pressure state and is a third refrigerant. It flows into the pipe 19. Since the second on-off valve 42 is in the open state, the refrigerant flowing from the first refrigerant pipe 18a into the third refrigerant pipe 19 merges with the refrigerant flowing through the second heat source side heat exchanger 12b and passes through the second refrigerant pipe 18b. Then, it flows into the inter-refrigerant heat exchanger 14 and condenses. On the other hand, the refrigerant that has flowed into the first throttle device 16 from the first heat source side heat exchanger 12a is decompressed in the first throttle device 16 and then flows into the inter-refrigerant heat exchanger 14.

Here, as shown by the broken line arrow in FIG. 8, the case where the refrigerant flows from the first refrigerant pipe 18a to the second refrigerant pipe 18b in the second on-off valve 42 has been described, but the refrigerant flowing through the first throttle device 16 has been described. When the flow rate is large, the refrigerant flow direction of the second on-off valve 42 may be opposite.

Since the first on-off valve 41 is in the closed state and the third on-off valve 43 is in the open state, the refrigerant flowing through the first throttle device 16 flows into the suction side of the compressor 10 via the injection pipe 44. .. In this way, the refrigerant flowing through the first throttle device 16 does not flow into the refrigerant pipes flowing through the indoor units 2a and 2b. Therefore, there is an effect of reducing the pressure loss in the refrigerant pipes flowing from the outdoor unit 1 to the indoor units 2a and 2b.

Further, in the cooling operation mode of the second embodiment, the opening degree of the first throttle device 16 may be increased. By making the refrigerant outlet of the inter-refrigerant heat exchanger 14 wet, the wet refrigerant can flow into the compressor 10 and the discharge temperature can be reduced.

In the second embodiment, in the cooling operation mode, the temperature of the refrigerant discharged by the compressor 10 can be prevented from becoming too high by flowing the refrigerant of intermediate pressure into the suction side of the compressor 10. Further, since the intermediate pressure refrigerant does not flow into the refrigerant pipes flowing to the indoor units 2a and 2b, it is possible to suppress the reduction of the pressure loss. Therefore, the refrigerant heat exchanger 14 can be effectively used even in the cooling operation mode.

1, 1a outdoor unit, 2a, 2b indoor unit, 3 liquid main pipe, 4 gas main pipe, 5a, 5b liquid branch pipe, 6a, 6b gas branch pipe, 10 compressor, 11 flow path switching device, 12 heat source side heat exchanger , 12a 1st heat source side heat exchanger, 12b 2nd heat source side heat exchanger, 13 accumulator, 14 inter-refrigerant heat exchanger, 15 2nd throttle device, 16 1st throttle device, 17 heat source side fan, 18a 1st refrigerant Piping, 18b 2nd refrigerant piping, 19 3rd refrigerant piping, 20a, 20b load side throttle device, 21a, 21b load side heat exchanger, 22a, 22b load side fan, 23a, 23b room temperature sensor, 30 control device, 41st 1 on-off valve, 42 2nd on-off valve, 43 3rd on-off valve, 44 injection piping, 50a, 50b refrigerant circuit, 61 flat tube, 61a heat transfer tube, 62 heat transfer tube, 71, 72 heat dissipation fins, 80 processing circuit, 81 processor , 82 memory, 100, 101 air exchanger.

Claims (9)

1. The compressor, the heat source side heat exchanger including the first heat source side heat exchanger and the second heat source side heat exchanger connected in parallel, the load side throttle device, and the load side heat exchanger are connected by piping. , A refrigerant circuit in which non-co-boiling mixed refrigerant circulates,
   The first refrigerant pipe and the second refrigerant pipe that divide the refrigerant flowing out from the load side throttle device during the heating operation and distribute it to the heat source side heat exchanger.
   A first throttle device provided in the first refrigerant pipe to reduce the pressure of the refrigerant flowing into the first heat source side heat exchanger via the first refrigerant pipe during the heating operation.
   A second throttle device provided in the second refrigerant pipe to reduce the pressure of the refrigerant flowing into the second heat source side heat exchanger via the second refrigerant pipe during the heating operation.
   Inter-refrigerant heat that exchanges heat between the refrigerant that flows between the second throttle device and the second heat source side heat exchanger in the second refrigerant pipe and the refrigerant that flows into the first throttle device during the heating operation. With a exchanger,
   In the first heat source side heat exchanger and the second heat source side heat exchanger, the pressure loss of the refrigerant flowing through the first heat source side heat exchanger is the pressure loss of the refrigerant flowing through the second heat source side heat exchanger. Larger configuration,
   Air conditioner.
2. The heat transfer area of the first heat source side heat exchanger is larger than the heat transfer area of the second heat source side heat exchanger.
   The air conditioner according to claim 1.
3. The flow path length of the heat transfer tube of the first heat source side heat exchanger is longer than the flow path length of the heat transfer tube of the second heat source side heat exchanger.
   The air conditioner according to claim 2.
4. The flow path cross-sectional area of the first heat source side heat exchanger is smaller than the flow path cross-sectional area of the second heat source side heat exchanger.
   The air conditioner according to any one of claims 1 to 3.
5. The first heat source side heat exchanger has a configuration in which the cross-sectional area of the flow path becomes larger as it approaches from the inlet side where the refrigerant flows in during the heating operation to the outlet side where the refrigerant flows out.
   The air conditioner according to claim 1.
6. The second heat source side heat exchanger is arranged on the wind side of the first heat source side heat exchanger.
   The air conditioner according to any one of claims 1 to 5.
7. It further has a control device for controlling the opening ratio of the first diaphragm device and the second diaphragm device.
   The control device is
   The opening ratio is controlled so that the pressure loss of the refrigerant flowing through the first heat source side heat exchanger is larger than the pressure loss of the refrigerant flowing through the second heat source side heat exchanger.
   The air conditioner according to any one of claims 2 to 6.
8. During the heating, the pressure change of the refrigerant flowing through the first heat source side heat exchanger corresponds to the temperature gradient of the non-azeotropic mixed refrigerant.
   The air conditioner according to any one of claims 1 to 7.
9. A flow path switching device that circulates the refrigerant discharged from the compressor during the heating operation to the load side heat exchanger and circulates the refrigerant discharged from the compressor to the heat source side heat exchanger during the cooling operation.
   In the first refrigerant pipe, a first on-off valve provided between the confluence point of the first refrigerant pipe and the pipe connected to the load-side throttle device and the inter-refrigerant heat exchanger.
   The first refrigerant pipe connects between the first heat source side heat exchanger and the first throttle device, and the second refrigerant pipe connects between the second heat source side heat exchanger and the refrigerant heat exchanger. 3rd refrigerant pipe and
   The second on-off valve provided in the third refrigerant pipe and
   An injection pipe that branches from between the refrigerant heat exchanger and the first on-off valve and is connected to the suction side of the compressor.
   Further having a third on-off valve provided in the injection pipe,
   During the cooling operation, the first on-off valve is in the closed state, and the second on-off valve and the third on-off valve are in the open state.
   The air conditioner according to any one of claims 1 to 8.

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