JP2021096057A - Outdoor unit and air conditioner including the same - Google Patents

Abstract

To provide an outdoor unit which can reliably cause supercooling at the upstream side of an expansion valve even if a non-azeotropic refrigerant mixture is used.SOLUTION: An outdoor unit 2 includes: an expansion valve 7 which expands a non-azeotropic refrigerant mixture formed by mixing a low boiling refrigerant and a high boiling refrigerant having different boiling temperatures; and a heat transmission part which thermally connects the upstream side with the downstream side of refrigerant flow in the expansion valve 7. The heat transmission part includes a heat conductive member 15 fixed to a first refrigerant pipe 13 and a second refrigerant pipe 14 connected to the expansion valve 7. A material such as graphene is used as the heat conduction member 15.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an outdoor unit and an air conditioner equipped with the outdoor unit.

Among the mixed refrigerants used in refrigerators, there are non-azeotropic mixed refrigerants in which refrigerants having different boiling points are mixed. The non-azeotropic mixed refrigerant causes temperature slip as shown in FIG. That is, since the boiling points and condensation points of each mixed refrigerant are different, the isotherms in the moist steam (between the saturated liquid line and the saturated steam line) are not constant in pressure (p) like a single refrigerant, and p. On the −h diagram, it becomes a downward-sloping isotherm. That is, temperature slip occurs in the non-azeotropic mixed refrigerant (Patent Document 1).

JP-A-2018-141574

Due to the temperature slip, the difference between the refrigerant temperature at the outlet of the condenser and the air temperature becomes small, which makes it difficult to secure supercooling.
In order to promote supercooling, it is necessary to add an additional amount of refrigerant. However, an excessive increase in the amount of refrigerant causes deterioration of performance (COP) and a risk of compressor failure due to liquid backing.
If the supercooling is insufficient, the electronic expansion valve (EEV) becomes inoperable, which makes it difficult to reliably cool the liquid refrigerant to the evaporator, and may increase the refrigerant flow noise.

The present disclosure has been made in view of such circumstances, and is an outdoor unit capable of reliably supercooling on the upstream side of the expansion valve even when a non-azeotropic mixed refrigerant is used. It is an object of the present invention to provide an air conditioner equipped with the above.

In order to solve the above problems, the outdoor unit according to one aspect of the present disclosure includes an expansion valve that expands a non-coboiling mixed refrigerant in which a low boiling point refrigerant and a high boiling point refrigerant having different boiling points are mixed, and an expansion valve of the expansion valve. It is provided with a heat transfer unit that thermally connects the upstream side and the downstream side in the refrigerant flow.

Even when a non-azeotropic mixed refrigerant is used, supercooling can be reliably applied on the upstream side of the expansion valve.

It is a schematic block diagram which showed the refrigerant circuit which concerns on 1st Embodiment of this disclosure. It is a side view which showed the internal structure of an outdoor unit. It is a front view which showed the installation state of the heat conduction member. It is a front view which showed the groove formed in the heat conduction member. It is a ph diagram of 1st Embodiment. It is a schematic block diagram which showed the refrigerant circuit which concerns on 2nd Embodiment of this disclosure. It is a front view which showed the pipe fixing part. It is a schematic block diagram which showed the refrigerant circuit which concerns on 3rd Embodiment of this disclosure. It is a ph diagram of the 3rd embodiment. It is a schematic block diagram which showed the 4th Embodiment of this disclosure. It is a ph diagram of a non-azeotropic mixed refrigerant.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.
[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows the refrigerant circuit configuration of the air conditioner 1 of the present embodiment. The air conditioner 1 can perform heating operation and cooling operation by switching the four-way valve 4 provided on the discharge side of the compressor 3. In FIG. 1, the direction indicated by the solid arrow A1 indicates the refrigerant flow direction during the heating operation, and the direction indicated by the broken arrow A2 indicates the refrigerant flow direction during the cooling operation or the defrost operation.

The air conditioner 1 uses, for example, R454C, which is a non-azeotropic mixed refrigerant in which R32 and R1234yf are mixed, as the refrigerant. R32 is a low boiling point refrigerant having a low boiling point with respect to R123yf. R1234yf is a high boiling point refrigerant having a high boiling point with respect to R32. Instead of R454C, R454B or another non-azeotropic mixed refrigerant of the R400 series may be used.

The air conditioner 1 includes a compressor 3 for compressing a non-azeotropic mixed refrigerant (hereinafter, may be simply referred to as “refrigerant”), a four-way valve 4, an outdoor heat exchanger 5, an expansion valve 7, and an indoor chamber. It is equipped with a heat exchanger 9. A refrigerant circuit that performs a refrigeration cycle is configured by connecting the compressor 3, the four-way valve 4, the outdoor heat exchanger 5, the expansion valve 7, and the indoor heat exchanger 9 with a refrigerant pipe.

The compressor 3, the four-way valve 4, the outdoor heat exchanger 5, and the expansion valve 7 are installed in the outdoor unit 2. The indoor heat exchanger 9 is installed in the indoor unit 10.

The compressor 3 is, for example, a scroll compressor or a rotary compressor, and is driven by an electric motor (not shown). The electric motor includes an inverter device, and the rotation speed is arbitrarily changed by a command from a control unit (not shown).

The four-way valve 4 is switched so that the refrigerant discharged from the compressor 3 is guided to the indoor heat exchanger 9 during the heating operation, and the refrigerant discharged from the compressor 3 is guided to the indoor heat exchanger 9 during the cooling operation or the defrost operation. It is switched so as to be guided to 5. The control of the four-way valve 4 is performed by a control unit (not shown).

The outdoor heat exchanger 5 operates as an evaporator during the heating operation and as a condenser during the cooling operation and the defrost operation. Air (outside air) is sent from the outdoor fan 6 to the outdoor heat exchanger 5.

The indoor heat exchanger 9 operates as a condenser during the heating operation, and operates as an evaporator during the cooling operation and the defrost operation. Air is sent from the indoor fan 11 toward the room to the indoor heat exchanger 9.

The expansion valve 7 expands the refrigerant condensed and liquefied by the heat exchangers 5 and 9 that operate as a condenser. The opening degree of the expansion valve 7 is controlled by the control unit.

The first refrigerant pipe 13 and the second refrigerant pipe 14 are connected to both sides of the expansion valve 7. The first refrigerant pipe 13 is an upstream pipe in the refrigerant flow during the cooling operation, and is a downstream pipe in the refrigerant flow during the heating operation. The second refrigerant pipe 14 is a downstream pipe in the refrigerant flow during the cooling operation, and is an upstream pipe in the refrigerant flow during the heating operation.

A heat conductive member 15 is provided between the first refrigerant pipe 13 and the second refrigerant pipe 14 as a heat transfer unit that thermally connects the pipes 13 and 14. As the heat conductive member 15, a material having a high thermal conductivity equal to or higher than that of a metal such as stainless steel is used, and for example, copper, graphene, or the like can be used.

FIG. 2 shows the internal structure of the outdoor unit 2. As shown in the figure, an expansion valve 7 is provided on the side of the compressor 3. Below the expansion valve 7, the first refrigerant pipe 13 and the second refrigerant pipe 14 are arranged so as to extend downward in a state parallel to each other.

As shown in FIG. 3, a heat conductive member 15 is fixed directly below the expansion valve 7 so as to sandwich and cover the first refrigerant pipe 13 and the second refrigerant pipe 14 that are separated from each other. As shown in FIG. 4, the heat conductive member 15 is formed with grooves 15a and 15b corresponding to the shapes of the first refrigerant pipe 13 and the second refrigerant pipe 14. The first refrigerant pipe 13 and the second refrigerant pipe 14 are fitted into the grooves 15a and 15b so as to be housed.

According to this embodiment, the following effects are exhibited.
A heat conductive member 15 for thermally connecting the first refrigerant pipe 13 and the second refrigerant pipe 14 provided on the upstream side and the downstream side in the refrigerant flow of the expansion valve 7 is provided, whereby the expansion valve 7 is provided. The refrigerant on the upstream side of the expansion valve 7 can be cooled by the refrigerant on the downstream side that has been squeezed and cooled by. As a result, as shown in FIG. 5, the supercooled B1 can be attached to the refrigerant on the upstream side guided to the expansion valve 7.

Since it was decided to fix the first refrigerant pipe 13 and the second refrigerant pipe 14 connected to the expansion valve 7 by using the heat conduction member 15, the heat conduction between the first refrigerant pipe 13 and the second refrigerant pipe 14 was performed. Can be improved.
Since the first refrigerant pipe 13 and the second refrigerant pipe 14 are fixed via the heat conductive member 15, the design is relatively free regardless of the shapes of the first refrigerant pipe 13 and the second refrigerant pipe 14. can do. In particular, since the grooves 15a and 15b are formed in the heat conductive member 15 according to the shape of the pipe, the design can be easily performed.

[Second Embodiment]
Next, a second embodiment of the present disclosure will be described. This embodiment differs from the first embodiment in the configuration of the heat transfer unit that thermally connects the first refrigerant pipe 13 and the second refrigerant pipe 14. Therefore, in the following description, the differences from the first embodiment will be described, and the same components will be designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, the heat transfer unit of the present embodiment physically connects the first refrigerant pipe 13 and the second refrigerant pipe 14 to each other at the position closest to the expansion valve 7 indicated by reference numeral C. A pipe fixing portion 17 for contacting and fixing is provided.

More specifically, as shown in FIG. 7, the pipe fixing portion 17 uses a clip 18 to bring the first refrigerant pipe 13 and the second refrigerant pipe 14 into contact with each other and fix them. As shown in the figure, the number of clips 18 may be two, one or three or more. Further, instead of the clip 18, the pipes 13 and 14 may be fixed to each other by brazing.

According to this embodiment, the following effects are exhibited.
Since it was decided to provide a pipe fixing portion 17 for physically contacting and fixing the first refrigerant pipe 13 and the second refrigerant pipe 14 connected to the expansion valve 7, the first refrigerant pipe 13 and the second refrigerant pipe 14 are provided. The heat conduction with 14 can be improved.
Since it is only necessary to physically contact and fix the first refrigerant pipe 13 and the second refrigerant pipe 14 to each other, the structure can be made lightweight and space-saving.

[Third Embodiment]
Next, a third embodiment of the present disclosure will be described. This embodiment differs from the first embodiment in the configuration of the heat transfer portion that thermally connects the upstream side pipe and the downstream side pipe of the expansion valve 7. Therefore, in the following description, the differences from the first embodiment will be described, and the same components will be designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 8, an expansion valve 7a for cooling and an expansion valve 7b for heating are provided. In FIG. 8, the direction of the refrigerant flow during cooling is indicated by a white arrow.
A third refrigerant pipe 20 is provided between the cooling expansion valve 7a and the heating expansion valve 7b. The third refrigerant pipe 20 and the second refrigerant pipe 14 are connected to the cooling expansion valve 7a, and the third refrigerant pipe 20 and the first refrigerant pipe 13 are connected to the heating expansion valve 7b. There is.

At the time of cooling, the opening degree is controlled for the cooling expansion valve 7a, and the opening degree is not controlled while the heating expansion valve 7b is open. Therefore, at the time of cooling, the third refrigerant pipe 20 becomes the upstream side pipe in the refrigerant flow, and the second refrigerant pipe 14 becomes the downstream side pipe in the refrigerant flow.
At the time of heating, the opening degree is controlled for the heating expansion valve 7b, and the opening degree is not controlled while the cooling expansion valve 7a is open. Therefore, at the time of heating, the third refrigerant pipe 20 becomes the upstream side pipe in the refrigerant flow, and the first refrigerant pipe 13 becomes the downstream side pipe in the refrigerant flow.
In this way, the third refrigerant pipe 20 provided between the cooling expansion valve 7a and the heating expansion valve 7b is always the upstream pipe in the refrigerant flow.

A supercooling heat exchanger (heat transfer unit) 25 is provided between the third refrigerant pipe 20 and the suction pipe 22 connected to the suction side of the compressor 3. The supercooling heat exchanger 25 is a liquid gas heat exchanger, and for example, a double tube heat exchanger can be used.

According to this embodiment, the following effects are exhibited.
Since it was decided to provide a supercooling heat exchanger 25 for heat exchange between the third refrigerant pipe 20 which is the upstream side pipe connected to the expansion valves 7a and 7b and the suction pipe 22 connected to the compressor 3, evaporation. The liquid refrigerant on the upstream side of the expansion valves 7a and 7b can be cooled by using the suction refrigerant after leaving the vessel. Since the suction refrigerant having a temperature lower than that of the refrigerant on the downstream side of the expansion valves 7a and 7b and on the upstream side of the evaporator is used, cooling can be performed more effectively. As a result, as shown in FIG. 9, the supercooled B2 can be attached. Further, since the refrigerant after evaporation is heated by the refrigerants of the expansion valves 7a and 7b, the degree of superheat B3 can be added as shown in FIG.

[Fourth Embodiment]
Next, a fourth embodiment of the present disclosure will be described. This embodiment differs from the first embodiment in the configuration of the heat transfer portion that thermally connects the upstream side pipe and the downstream side pipe of the expansion valve 7. Therefore, in the following description, the differences from the first embodiment will be described, and the same components will be designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 10, a gas-liquid separator 30 is provided on the upstream side of the refrigerant flow of the expansion valve 7 and on the downstream side of the condenser. The gas-liquid separator 30 is a container that requires a predetermined volume inside.

The upstream end of the first upstream side pipe 32 is connected below the gas-liquid separator 30. The downstream side of the first upstream side pipe 32 is connected to the expansion valve 7. The liquid refrigerant separated by the gas-liquid separator 30 flows through the first upstream side pipe 32.

The upstream end of the second upstream side pipe 33 is connected above the gas-liquid separator 30. The downstream side of the second upstream side pipe 33 is connected to the intermediate position of the first upstream side pipe 32. The gas refrigerant separated by the gas-liquid separator 30 is guided to the second upstream pipe 33.

A heat transfer unit 35 is provided at an intermediate position of the second upstream side pipe 33. The heat transfer unit 35 connects the second upstream side pipe 33 and the downstream side pipe 37 connected to the downstream side of the refrigerant flow of the expansion valve 7. As the heat transfer portion 35, the heat conductive member 15 shown in the first embodiment, the pipe fixing portion 17 shown in the second embodiment, and the like can be used.

The second upstream side pipe 33 is provided in the heat transfer unit 35 so that the refrigerant flow flowing through the second upstream side pipe 33 becomes a counter flow with respect to the refrigerant flowing through the downstream side pipe 37. Specifically, as shown in FIG. 10, the second upstream side pipe 33 is extended downward, then inverted, directed upward, and then connected to the heat transfer portion 35. As a result, the heat transfer performance of the heat transfer unit 35 can be improved.

The effects of this embodiment are as follows.
The gas refrigerant separated by the gas-liquid separator 30 flows through the second upstream side pipe 33, is squeezed by the expansion valve 7 via the heat transfer portion 35, and is cooled by the refrigerant flowing through the downstream side pipe 37. .. As a result, the refrigerant flowing through the second upstream side pipe 33 is condensed and joins the first upstream side pipe 32. The liquid refrigerant flowing through the first upstream side pipe 32 is cooled by merging with the refrigerant flowing through the second upstream side pipe 33, and supercooling is added.

In the present embodiment, the gas refrigerant flowing through the second upstream pipe 33 is cooled by the refrigerant flowing through the downstream pipe 37, but the gas refrigerant flowing through the suction pipe 22 is used as in the third embodiment. 2 The gas refrigerant flowing through the upstream pipe 33 may be cooled.
Further, in the present embodiment, the non-azeotropic mixed refrigerant is used as the refrigerant, but a single refrigerant or a non-azeotropic mixed refrigerant may be used instead of the non-azeotropic mixed refrigerant.

The outdoor unit and the air conditioner provided with the outdoor unit according to each of the above-described embodiments are grasped as follows, for example.

The outdoor unit (2) according to one aspect of the present disclosure includes an expansion valve (7,7a, 7b) for expanding a non-coboiling mixed refrigerant in which a low boiling point refrigerant having a different boiling point and a high boiling point refrigerant are mixed, and the expansion. It is provided with heat transfer portions (15, 17, 25, 35) that thermally connect the upstream side and the downstream side in the refrigerant flow of the valves (7, 7a, 7b).

By providing a heat transfer section that thermally connects the upstream side and the downstream side in the refrigerant flow of the expansion valve, the refrigerant on the upstream side of the expansion valve is cooled by the refrigerant on the downstream side that has been throttled and cooled by the expansion valve. can do. As a result, supercooling can be applied to the refrigerant on the upstream side guided to the expansion valve.

In the outdoor unit (2) according to one aspect of the present disclosure, the heat transfer unit (15) is connected to the expansion valve (7) in the upstream piping (13, 14) and the downstream piping (14, 13). It is provided with a heat transfer member (15) fixed to the relative.

Since the upstream pipe and the downstream pipe connected to the expansion valve are fixed by using the heat conductive member, the heat conduction between the upstream pipe and the downstream pipe can be improved.
Since the upstream pipe and the downstream pipe are fixed via the heat conductive member, the design can be performed relatively freely without depending on the shapes of the upstream pipe and the downstream pipe.
As the heat conductive member, a material having a high thermal conductivity equal to or higher than that of a metal such as stainless steel is used, and for example, copper, graphene, or the like can be used.

In the outdoor unit (2) according to one aspect of the present disclosure, the heat transfer unit (17) has an upstream pipe (13, 14) and a downstream pipe (14, 13) connected to the expansion valve (7). It is provided with a pipe fixing portion (17) for physically contacting and fixing the two.

Since it was decided to provide a pipe fixing part that physically contacts and fixes the upstream pipe and the downstream pipe connected to the expansion valve, it is possible to improve the heat conduction between the upstream pipe and the downstream pipe. it can.
Since it is only necessary to physically contact and fix the upstream pipe and the downstream pipe to each other, the structure can be lightweight and space-saving.
Examples of the pipe fixing portion include a configuration in which the upstream pipe and the downstream pipe are brazed, and a configuration in which the upstream pipe and the downstream pipe are fixed to each other with clips.

In the outdoor unit (2) according to one aspect of the present disclosure, the heat transfer unit (25) is connected to the upstream pipe (20) and the compressor (3) connected to the expansion valves (7a, 7b). It is provided with a supercooling heat exchanger (25) that exchanges heat with the suction pipe (22).

Since it was decided to provide a supercooling heat exchanger that exchanges heat between the upstream pipe connected to the expansion valve and the suction pipe connected to the compressor, the expansion valve uses the suction refrigerant after leaving the evaporator. The liquid refrigerant on the upstream side can be cooled. Since the suction refrigerant having a temperature lower than that on the downstream side of the expansion valve and on the upstream side of the evaporator is used, cooling can be performed more effectively.
The supercooling heat exchanger is a liquid gas heat exchanger, and for example, a double tube heat exchanger can be used.

The outdoor unit (2) according to one aspect of the present disclosure is a gas-liquid separator (30) provided on the upstream side in the refrigerant flow of the expansion valve (7) and on the downstream side of the condenser, and the gas-liquid separation. The first upstream side pipe (32) provided between the liquid phase side of the vessel (30) and the expansion valve (7), and the gas phase side and the first upstream side of the gas-liquid separator (30). A second upstream side pipe (33) provided between the middle position of the pipe (32) is provided, and the heat transfer unit (35) is a downstream side pipe (7) connected to the expansion valve (7). 37) and the second upstream side pipe (33) are thermally connected.

The gas refrigerant separated by the gas-liquid separator flows through the second upstream side pipe, is throttled by the expansion valve via the heat transfer portion, and is cooled by the refrigerant flowing through the downstream side pipe. As a result, the refrigerant flowing through the second upstream side pipe is condensed and joins the first upstream side pipe. The liquid refrigerant flowing through the first upstream side pipe is cooled by merging with the refrigerant flowing through the second upstream side pipe, and supercooling is added.
The refrigerant may be a single refrigerant or a non-azeotropic mixed refrigerant instead of the non-azeotropic mixed refrigerant.

In the outdoor unit (2) according to one aspect of the present disclosure, the second upstream side pipe (33) and the downstream side pipe (37) are the second upstream side pipe (33) in the heat transfer unit (35). ) And the refrigerant flowing through the downstream pipe (37) are provided so as to be countercurrent.

Since the refrigerant flowing through the second upstream pipe and the refrigerant flowing through the downstream pipe are countercurrent, the heat transfer performance can be further improved.

The air conditioner (1) includes the outdoor unit (2) according to any one of the above and the indoor unit (10) connected to the outdoor unit.

1 Air conditioner 2 Outdoor unit 3 Compressor 4 Four-way valve 5 Outdoor heat exchanger 6 Outdoor fan 7 Expansion valve 7a Cooling expansion valve 7b Heating expansion valve 9 Indoor heat exchanger 10 Indoor unit 11 Indoor fan 13 First piping 14 2nd pipe 15 Heat transfer member (heat transfer part)
17 Piping fixing part (heat transfer part)
18 Clip 20 Third refrigerant pipe 22 Suction pipe 25 Supercooling heat exchanger (heat transfer part)
30 Gas-liquid separator 32 1st upstream side piping 33 2nd upstream side piping 35 Heat transfer section 37 Downstream side piping

Claims (7)

An expansion valve that expands a non-azeotropic mixed refrigerant that is a mixture of a low boiling point refrigerant and a high boiling point refrigerant having different boiling points.
A heat transfer unit that thermally connects the upstream side and the downstream side in the refrigerant flow of the expansion valve,
The outdoor unit equipped with. The outdoor unit according to claim 1, wherein the heat transfer unit includes an upstream pipe connected to the expansion valve and a heat conductive member fixed to the downstream pipe. The outdoor unit according to claim 1, wherein the heat transfer portion includes a pipe fixing portion for physically contacting and fixing the upstream pipe and the downstream pipe connected to the expansion valve. The outdoor unit according to claim 1, wherein the heat transfer unit includes a supercooling heat exchanger that exchanges heat between the upstream pipe connected to the expansion valve and the suction pipe connected to the compressor. A gas-liquid separator provided on the upstream side of the refrigerant flow of the expansion valve and on the downstream side of the condenser,
The first upstream side pipe provided between the liquid phase side of the gas-liquid separator and the expansion valve, and
A second upstream pipe provided between the gas phase side of the gas-liquid separator and an intermediate position of the first upstream pipe,
With
The outdoor unit according to claim 1, wherein the heat transfer unit thermally connects the downstream side pipe connected to the expansion valve and the second upstream side pipe. The second upstream side pipe and the downstream side pipe are provided in the heat transfer portion so that the refrigerant flowing through the second upstream side pipe and the refrigerant flowing through the downstream side pipe are countercurrent. Item 5. The outdoor unit according to item 5. The outdoor unit according to any one of claims 1 to 6 and
The indoor unit connected to the outdoor unit and
Air conditioner equipped with.

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