JP7624618B2 - Air conditioners - Google Patents

Description

This disclosure relates to an air conditioner.

For example, Patent Document 1 discloses an air conditioner that uses a flammable refrigerant as the working refrigerant.

Patent Document 1 discloses an air conditioner that houses a heat exchanger that uses a flammable refrigerant as the working refrigerant and electrical equipment within a casing. The air conditioner described in Patent Document 1 is characterized in that the electrical equipment is positioned above the heat exchanger, at the top of the casing, and offset to one side of the heat exchanger in the width direction.

Patent No. 3807004

However, the air conditioner described in Patent Document 1 still has room for improvement in terms of improving the safety of air conditioners that use flammable refrigerants.

Therefore, the object of this disclosure is to solve the above problems and provide an air conditioner that can improve the safety of air conditioners that use flammable refrigerants.

An air conditioner according to one aspect of the present disclosure is an air conditioner that uses a flammable refrigerant, and includes a housing that forms the exterior of the indoor unit, a heat exchanger housed within the housing, a fan disposed inside the heat exchanger, a fan motor connected to the fan, electrical equipment including a control circuit that performs overall control of the indoor unit, and an isolation wall disposed within the housing that divides the interior of the housing into a first space and a second space, the heat exchanger extending from one end of the heat exchanger and folding back, and including a plurality of heat transfer tubes through which the flammable refrigerant flows, and a brazing portion brazed to the plurality of heat transfer tubes at one end of the heat exchanger, the electrical equipment and the fan motor being disposed in the first space, and the brazing portion being disposed in the second space.

This disclosure makes it possible to improve the safety of air conditioners that use flammable refrigerants.

FIG. 1 is a schematic diagram of an air conditioner according to a first embodiment of the present disclosure. Schematic diagram of the internal structure of the indoor unit Schematic diagram of heat transfer tube and brazed part Side view of indoor unit Schematic diagram of sensor-related components Flowchart of air conditioner operation Schematic diagram of the internal structure of an indoor unit according to a first modified example. FIG. 13 is a schematic diagram of an internal structure of an indoor unit according to a second embodiment of the present disclosure. Schematic diagram of the isolation wall Schematic diagram of the internal structure of an indoor unit according to a second modified example. Schematic diagram of the internal structure of an indoor unit according to Modification 3 Schematic diagram of the internal structure of an indoor unit according to Modification 4

(Background to this disclosure)
An example of a refrigerant used in air conditioners is R32. The global warming potential (GWP) of R32 is 675, and from the perspective of preventing global warming, the use of refrigerants such as isobutane or propane, which have a lower global warming potential, has been proposed.

However, refrigerants such as isobutane and propane are flammable. On the other hand, electrical equipment can generate ignition sources such as sparks. If flammable refrigerant leaks into the indoor unit of an air conditioner and comes into contact with sparks or the like generated by electrical equipment, the flammable refrigerant may ignite inside the indoor unit. The resulting fire may further ignite the flammable refrigerant that has leaked into the room, causing harm to users. Therefore, there is a demand to prevent ignition of flammable refrigerant inside the indoor unit and improve the safety of air conditioners that use flammable refrigerants.

Therefore, the inventors identified the brazed parts of the heat exchanger as the parts of the indoor unit where flammable refrigerant is likely to leak, and discovered a configuration that prevents flammable refrigerant leaking from the brazed parts from reaching electrical components.

Based on these new findings, the inventors have come to the following disclosure.

The air conditioner of the first aspect of the present disclosure is an air conditioner that uses a flammable refrigerant and includes a housing that forms the exterior of the indoor unit, a heat exchanger housed within the housing, a fan disposed inside the heat exchanger, a fan motor connected to the fan, electrical components including a control circuit that performs overall control of the indoor unit, and an isolation wall disposed within the housing that divides the interior of the housing into a first space and a second space, the heat exchanger includes a plurality of heat transfer tubes that extend from one end of the heat exchanger to the other end and turn back, through which the flammable refrigerant flows, and a brazing portion brazed to the plurality of heat transfer tubes at the one end side of the heat exchanger, the electrical components and the fan motor are disposed in the first space, and the brazing portion is disposed in the second space.

This configuration prevents flammable refrigerant from reaching electrical equipment and the fan motor, and prevents sparks and other ignition sources from the electrical equipment and the fan motor. This prevents ignition of flammable refrigerant and improves the safety of air conditioners that use flammable refrigerants.

In the air conditioner of the second aspect of the present disclosure, the partition wall may be disposed on the other end side of the heat exchanger, and the heat exchanger may be disposed in the second space.

This configuration prevents flammable refrigerant from reaching electrical equipment and the fan motor even if it leaks from the heat transfer tube.

In the air conditioner of the third aspect of the present disclosure, the partition wall may be disposed on one end side of the heat exchanger, and the heat exchanger may be disposed in the second space.

This configuration prevents flammable refrigerant from reaching electrical equipment and the fan motor, and further prevents sparks and other ignition sources from the electrical equipment and the fan motor.

In the air conditioner of the fourth aspect of the present disclosure, the isolation wall may be disposed on the heat exchanger inside the brazed portion.

This configuration prevents flammable refrigerant from reaching electrical equipment and the fan motor, and further prevents sparks and other ignition sources from the electrical equipment and the fan motor.

In the air conditioner of the fifth aspect of the present disclosure, one or more openings may be formed in the upper portion of the partition wall.

With this configuration, even if a flammable refrigerant reaches the electrical equipment and fan motor and an explosion occurs in the first space, the pressure of the explosion can be released to the outside of the first space through the opening.

In the air conditioner of the sixth aspect of the present disclosure, the upper part of the partition wall may be formed of a mesh member.

With this configuration, even if an explosion occurs in the first space, the pressure of the explosion can be further released to the outside of the first space through the mesh member.

In the seventh aspect of the air conditioner of the present disclosure, the mesh member may be made of metal.

This configuration improves the durability of the mesh member.

In the air conditioner of the eighth aspect of the present disclosure, the spacing between the openings formed by the mesh member may be less than the quenching distance of the flammable refrigerant.

This configuration makes it possible to suppress flame propagation even if an explosion occurs in the first space.

In the air conditioner of the ninth aspect of the present disclosure, the fan motor has a shaft connected to the rotating shaft of the fan, and a through hole through which the shaft passes may be formed in the lower part of the isolation wall.

This configuration allows the indoor fan to be driven while the indoor fan motor is placed in the first space to improve the safety of air conditioners that use flammable refrigerants.

(Embodiment 1)
An air conditioner according to a first embodiment of the present disclosure will be described.

[Overall configuration]
Fig. 1 is a schematic diagram showing an example of an air conditioner 1 according to a first embodiment of the present disclosure. As shown in Fig. 1, the air conditioner 1 includes an indoor unit 10 and an outdoor unit 20. The indoor unit 10 and the outdoor unit 20 are connected via a refrigerant pipe 50.

The indoor unit 10 includes a first heat exchanger 11, an indoor fan 12, an indoor fan motor 13, a sensor 17, a first electrical component 30, and a portion of the refrigerant piping 50. The indoor unit 10 is placed indoors.

The outdoor unit 20 includes a second heat exchanger 21, an outdoor fan 22, a compressor 23, an expansion mechanism 24, a four-way valve 25, a second electrical component 40, and a portion of the refrigerant piping 50. The outdoor unit 20 is disposed outdoors.

The components of the indoor unit 10 are explained below.

<First heat exchanger>
For example, during cooling operation, the first heat exchanger 11 exchanges heat with the air and evaporates the refrigerant flowing into the first heat exchanger 11. As described below, the first heat exchanger 11 includes fins, heat transfer tubes 15, and brazed portions 16. The fins are made of a plurality of thin metal plates, and are arranged so that the surfaces of the metal plates are parallel to each other. The heat transfer tubes 15 are arranged perpendicular to the surfaces of the fins and penetrate the fins. The heat transfer tubes 15 and the brazed portions 16 will be described in detail later.

<Indoor fan>
The indoor fan 12 is disposed inside the first heat exchanger 11, and blows out toward the room the air whose temperature has been adjusted by the first heat exchanger 11. For example, the indoor fan 12 is a cross-flow fan.

<Indoor fan motor>
The indoor fan motor 13 is connected to the indoor fan 12 and drives the indoor fan 12. The indoor fan motor 13 is disposed in the indoor unit 10 together with the indoor fan 12.

<Sensor>
The sensor 17 detects information related to the flammable refrigerant inside the indoor unit 10. The sensor 17 is disposed around the first heat exchanger 11. The sensor 17 will be described in detail later.

<First Electrical Component>
The first electrical component 30 is composed of, for example, semiconductor elements. The first electrical component 30 includes a control circuit that performs overall control of the indoor unit 10. The first electrical component 30 includes a control board, a drive motor for a flap that covers the air outlet of the indoor unit 10, a cleaning motor for the indoor unit 10, etc. The first electrical component 30 is connected to an electronic circuit of the indoor unit 10 by a first electrical wiring 31.

<Refrigerant piping>
The refrigerant piping 50 is arranged to connect the first heat exchanger 11, the compressor 23, the four-way valve 25, the second heat exchanger 21, and the expansion mechanism 24. For example, the refrigerant piping 50 connects the first heat exchanger 11, the compressor 23, the four-way valve 25, the second heat exchanger 21, and the expansion mechanism 24 in this order.

The refrigerant pipe 50 has a flow path through which the refrigerant flows inside the refrigerant pipe 50, and circulates the refrigerant. For example, the refrigerant pipe 50 has a hollow cylindrical shape.

A flammable refrigerant such as isobutane or propane is used as the working refrigerant for the air conditioner 1. The working refrigerant may be a single flammable refrigerant or a mixture of another type of refrigerant and a flammable refrigerant.

Next, we will explain the components of the outdoor unit 20.

<Second Heat Exchanger>
For example, during cooling operation, the second heat exchanger 21 exchanges heat with the air and condenses the refrigerant flowing into the second heat exchanger 21. The second heat exchanger 21 further includes an outdoor fan 22 that blows the air, the temperature of which has been adjusted by the second heat exchanger 21, to the outside of the room.

<Compressor>
The compressor 23 is connected to the first heat exchanger 11 and the four-way valve 25 by a refrigerant pipe 50. The compressor 23 is used to compress the refrigerant that flows in from the refrigerant pipe 50.

<Expansion mechanism>
The expansion mechanism 24 is connected to the first heat exchanger 11 and the second heat exchanger 21 by the refrigerant piping 50. The expansion mechanism 24 is used to expand the refrigerant that has flowed in from the refrigerant piping 50. For example, the expansion mechanism 24 is an expansion valve.

<Four-way valve>
The four-way valve 25 is connected to the compressor 23, the first heat exchanger 11, and the second heat exchanger 21 by refrigerant piping 50. During cooling operation, the four-way valve 25 sends the refrigerant flowing out of the compressor 23 to the second heat exchanger 21 along a refrigerant flow direction 51. On the other hand, the four-way valve 25 changes the refrigerant flow direction depending on the operation mode of the air conditioner 1 (cooling operation, heating operation).

<Second Electrical Equipment>
The second electrical component 40 is formed of, for example, a semiconductor element, etc. The second electrical component 40 includes a control circuit that performs overall control of the outdoor unit 20. The second electrical component 40 is also connected to an electronic circuit of the outdoor unit 20 by a second electrical wiring 41.

Next, the indoor unit 10 will be described in more detail using Figures 2 to 4.

Figure 2 is a schematic diagram showing the internal structure of the indoor unit 10. Figure 3 is a schematic diagram of the heat transfer tube 15 and the brazed portion 16. Figure 4 is a side view of the indoor unit 10.

As shown in FIG. 2, the indoor unit 10 includes a first heat exchanger 11, an indoor fan 12, an indoor fan motor 13, a housing 14, a sensor 17, and a first electrical component 30.

The housing 14 constitutes the external appearance of the indoor unit 10. In the first embodiment, the first heat exchanger 11, the indoor fan 12, the indoor fan motor 13, the sensor 17, and the first electrical component 30 are housed within the housing 14. Although not shown, the housing 14 has an outlet through which the indoor fan 12 blows air into the room. The housing 14 may be formed of resin such as plastic.

As described above, the first heat exchanger 11 is connected to the refrigerant piping 50 and includes a plurality of heat transfer tubes 15 through which the flammable refrigerant flows, and brazed portions 16 that are brazed to the plurality of heat transfer tubes.

The heat transfer tube 15 extends from one end P1 of the first heat exchanger 11 to the other end P2 and then turns back. In the first embodiment, the heat transfer tube 15 has a U-shaped bend at the other end P2 of the first heat exchanger 11. The portions of the heat transfer tube 15 that extend along the first heat exchanger 11 may be parallel to each other.

The heat transfer tube 15 also has a flow path through which the refrigerant flows. For example, the heat transfer tube 15 has a hollow cylindrical shape similar to the refrigerant piping 50. Inside the heat transfer tube 15, the refrigerant flowing into the first heat exchanger 11 is evaporated by heat exchange with the surrounding air via the fins, for example during cooling operation.

The brazed portion 16 is a pipe that functions to connect the heat transfer tubes 15. The first heat exchanger 11 is provided with a plurality of brazed portions 16. The brazed portions 16 are brazed and connected to the plurality of heat transfer tubes 15 at one end P1 side of the first heat exchanger 11. The brazed portion 16 has a U-shaped bent shape so as to connect two heat transfer tubes 15 that extend along each other. As shown in FIG. 3, the end portion on one end side of the adjacent heat transfer tubes 15 is inserted into the brazed portion 16 and fixed by brazing. Furthermore, in the longitudinal direction of the first heat exchanger 11, the brazed portion 16 may be shorter than the heat transfer tubes 15.

Flammable refrigerant is prone to leaking from the brazed portion 16. If a through hole such as a pinhole is formed in the solder used to secure the heat transfer tube 15 and the brazed portion 16, the flammable refrigerant will leak from the inside to the outside of the brazed portion 16 through the through hole. For example, a pinhole is formed by corrosion of the solder.

2, the first electrical component 30 and the indoor fan motor 13 are arranged on the other end P2 side of the first heat exchanger 11 opposite the brazed portion 16 in order to be separated from the brazed portion 16. The "other end P2 side" of the first heat exchanger 11 means a position closer to the other end P2 than the center of the first heat exchanger 11. With this configuration, it is possible to prevent flammable refrigerant leaking from the brazed portion 16 from reaching the first electrical component 30 and the indoor fan motor 13, thereby improving the safety of the air conditioner 1. The first electrical component 30 and the indoor fan motor 13 may be separated from the other end P2 of the first heat exchanger 11 and have a gap between them. The indoor fan motor 13 may also be arranged closer to the first heat exchanger 11 than the first electrical component 30, or may be arranged coaxially with the indoor fan 12.

Furthermore, the air conditioner 1 has a power supply wiring 32 that electrically connects the outdoor unit 20 and the first electrical component 30. As shown in FIG. 4, the indoor unit 10 is attached to the indoor surface of the wall K of the building, and the power supply wiring 32 is arranged on the outside of the housing 14. The power supply wiring 32 may be arranged along the back surface of the housing 14 that faces the wall K. The power supply wiring 32 also extends from the indoor side to the outdoor side of the wall K. Although not shown, a through hole may be provided in the wall K, and the refrigerant piping 50 and the power supply wiring 32 may be passed through the through hole to the outside of the room. With this configuration, the number of through holes provided in the wall K can be reduced.

Returning to FIG. 2, the sensor 17 will be described. The sensor 17 may detect the flow rate or concentration of the flammable refrigerant as information about the flammable refrigerant. Alternatively, the sensor 17 may detect the presence or absence of the flammable refrigerant. The sensor 17 is, for example, an infrared sensor, a semiconductor sensor, or a catalytic combustion sensor.

The sensor 17 is disposed around the brazed portion 16. Thus, the sensor 17 may detect information about the flammable refrigerant leaking from the brazed portion 16. In addition, the sensor 17 may detect information about the flammable refrigerant leaking from another portion of the first heat exchanger 11 or the refrigerant piping 50. As shown in FIG. 2, in the first embodiment, the sensor 17 is disposed at a position lower than the brazed portion 16. The sensor 17 may be disposed at a position lower than the brazed portion 16A, which is located at the position where the distance between the inner wall on the bottom surface of the housing 14 and the brazed portion 16 is the shortest. The sensor 17 may be disposed in the housing 14 directly below the brazed portion 16, or may be disposed on the side of the housing 14 below the brazed portion 16. Furthermore, the sensor 17 may be directly attached to the brazed portion 16A on the refrigerant outflow side.

The sensor 17 will be explained in more detail using Figure 5.

Figure 5 is a schematic diagram illustrating components related to the sensor 17 in the indoor unit 10. For convenience, some components of the indoor unit 10 are omitted.

As shown in FIG. 5, the sensor 17 is electrically connected to a control circuit included in the first electrical component 30. Specifically, the sensor 17 is electrically connected to a processing unit 33 in the control circuit. Furthermore, the processing unit 33 is electrically connected to a communication unit 34 in the control circuit.

The elements constituting the processing unit 33 may, for example, include a memory (not shown) that stores a program that causes these elements to function, and a processing circuit (not shown) that corresponds to a processor such as a CPU (Central Processing Unit), and the processor may execute the program to cause these elements to function.

The processing unit 33 determines whether a flammable refrigerant has leaked based on information about the flammable refrigerant detected by the sensor 17. For example, when the sensor 17 detects the concentration of the flammable refrigerant, the processing unit 33 determines that a flammable refrigerant leak has occurred in the indoor unit 10 when the concentration of the flammable refrigerant exceeds a certain threshold value.

Although not shown, the processing unit 33 is further connected to the indoor fan motor 13. As described in detail later, the processing unit 33 drives the indoor fan motor 13 depending on the result of the determination of the leakage of the flammable refrigerant.

The communication unit 34 communicates the result of the flammable refrigerant leakage determination to an external device independent of the air conditioner 1. The leakage determination result is, for example, the flow rate, concentration, or presence or absence of flammable refrigerant. The external device has a display unit 35, which displays the flammable refrigerant leakage determination result determined by the processing unit 33. The display unit 35 is, for example, a display.

The communication unit 34 is compliant with a predetermined communication standard (e.g., LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark)) and includes a circuit for communicating with the display unit 35 of an external device. For example, the display of the remote controller of the air conditioner 1 may function as the display unit 35. The air conditioner 1 transmits information on the leak determination result to the remote controller via the communication unit 34. The remote controller may receive information on the leak determination result via the communication unit 34 and display the leak determination result on the display of the remote controller. The display of a smartphone may also function as the display unit 35. Specifically, the communication unit 34 of the air conditioner 1 and the smartphone may communicate with each other and the leak determination result may be displayed on the smartphone. For example, an application compatible with the air conditioner 1 may be provided on the smartphone, and the leak determination result may be displayed on the smartphone via the application.

[Action]
Next, an example of the operation of the air conditioner 1 will be described in detail with reference to Fig. 6. Fig. 6 is a flowchart of the operation of the air conditioner 1.

As shown in FIG. 6, the sensor 17 detects and acquires information regarding the flammable refrigerant (S11).

Next, the processing unit 33 determines whether or not a leak of flammable refrigerant has occurred based on the information about the flammable refrigerant detected by the sensor 17 (S12).

If no leakage has occurred (No in S12), the process returns to S11, and the sensor 17 detects information regarding the flammable refrigerant.

If a leak has occurred (Yes in S12), the processing unit 33 drives the indoor fan motor 13 (S13). Driving the indoor fan motor 13 causes the indoor fan 12 to blow air. The air blown by the indoor fan 12 moves the flammable refrigerant from inside the indoor unit 10 to outside the indoor unit 10. Therefore, the flammable refrigerant is diluted in the indoor unit 10, and the formation of a localized high concentration area of the flammable refrigerant can be suppressed. In other words, the flammable refrigerant can be suppressed from forming a flammable region.

The driving time, rotation speed, and other information related to the driving of the indoor fan motor 13 in S13 may be stored in advance in the processing unit 33. The driving time, rotation speed, and air blowing direction of the indoor fan 12 of the indoor fan motor 13 may be set according to the amount and type of flammable refrigerant in the air conditioner 1 and the area of the room in which the air conditioner 1 is installed. The air blowing direction of the indoor fan 12 may be set to upward.

Furthermore, in S13, among the electronic components of the first electrical component 30, electronic components other than the electronic components related to driving the indoor fan motor 13 may be stopped. This makes it possible to prevent the first electrical component 30 from generating sparks or the like that could be a source of ignition of the flammable refrigerant.

Next, the display unit 35 displays the result of the determination made by the processing unit 33 (S14).

Note that even if no leakage has occurred (No in S12), the display unit 35 may display the result of the determination made by the processing unit 33.

[effect]
According to the air conditioner 1 according to the first embodiment, the following effects can be achieved.

The air conditioner 1 uses a flammable refrigerant. The air conditioner 1 includes a housing 14, a first heat exchanger 11, an indoor fan 12, an indoor fan motor 13, and a first electrical component 30. The housing 14 constitutes the exterior of the indoor unit 10. The first heat exchanger 11 is housed within the housing 14. The indoor fan 12 is disposed inside the first heat exchanger 11. The indoor fan motor 13 is connected to the indoor fan 12. The first electrical component 30 includes a control circuit that controls the indoor unit 10 in an integrated manner. The first heat exchanger 11 includes a plurality of heat transfer tubes 15 and a brazed portion. The plurality of heat transfer tubes 15 extend from one end P1 of the first heat exchanger 11 to the other end P2 and turn back, and a flammable refrigerant flows inside the tubes. The brazed portion is brazed to the heat transfer tube 15 on the one end P1 side of the first heat exchanger 11. The first electrical component 30 and the indoor fan motor 13 are arranged on the other end P2 side of the first heat exchanger 11.

This configuration allows the first electrical component 30 and the indoor fan motor 13 to be positioned away from the brazed portion 16, which is prone to leaking flammable refrigerant, and prevents sparks and the like generated by the first electrical component 30 and the indoor fan motor 13 from becoming a source of ignition. This prevents ignition of the flammable refrigerant, improving the safety of the air conditioner 1 that uses a flammable refrigerant.

The air conditioner 1 further includes a sensor 17 that is disposed around the brazed portion 16 and detects information related to the flammable refrigerant. The control circuit has a processing unit 33 that determines whether or not there is a leak of the flammable refrigerant based on the information related to the flammable refrigerant detected by the sensor 17.

This configuration makes it possible to detect and determine if there is a leak of flammable refrigerant in the air conditioner 1.

The sensor 17 is positioned lower than the brazed portion 16.

With this configuration, the sensor 17 can detect leakage of flammable refrigerant that is heavier than air.

The processing unit 33 drives the indoor fan motor 13 depending on the result of the flammable refrigerant leakage determination.

This configuration prevents leaked flammable refrigerant from creating a flammable zone due to the airflow from the indoor fan 12 driven by the indoor fan motor 13.

The air conditioner 1 has a communication unit 34, which communicates the results of the flammable refrigerant leakage determination to an external device.

With this configuration, the result of the flammable refrigerant leakage determination can be communicated to the user of the air conditioner 1. This allows the user to take appropriate measures in the event of a flammable refrigerant leakage, such as ventilating the room or evacuating, thereby improving the safety of the air conditioner 1.

The first heat exchanger 11 may be referred to as a "heat exchanger", the indoor fan 12 as a "fan", the indoor fan motor 13 as a "fan motor", and the first electrical component 30 as an "electrical component".

Although an example has been described in which the first electrical component 30 and the indoor fan motor 13 are positioned away from the other end P2 of the first heat exchanger 11, this is not limiting. The first electrical component 30 and the indoor fan motor 13 only need to be positioned closer to the other end P2 than near the center of the first heat exchanger 11. Even with this configuration, the first electrical component 30 and the indoor fan motor 13 can be positioned away from the brazed portion 16.

Note that, although an example in which one end of the heat transfer tube 15 is inserted into the brazed portion 16 and fixed has been described, this is not limiting. The brazed portion 16 may be inserted into the end of one end of the heat transfer tube 15.

Although an example in which the heat transfer tube 15 and the brazed portion 16 are bent into a U-shape has been described, this is not limiting.

Although an example in which the first electrical component 30 is disposed farther from the first heat exchanger 11 than the indoor fan motor 13 has been described, this is not limiting. The first electrical component 30 may be disposed closer to the first heat exchanger 11 than the indoor fan motor 13.

Note that although an example in which the sensor 17 is positioned lower than the brazed portion 16 has been described, the present invention is not limited to this. For example, when a flammable refrigerant that is lighter than air is used as the working refrigerant, the sensor 17 may be positioned higher than the brazed portion 16.

Although an example in which the indoor unit 10 has one sensor 17 has been described, this is not limiting. For example, the indoor unit 10 may be provided with multiple sensors 17. The multiple sensors 17 may each detect different types of information related to the flammable refrigerant. Furthermore, the sensor 17 may be provided not only on one end P1 side of the first heat exchanger 11, but also on the center or other end P2 side of the first heat exchanger 11.

Note that, although an example has been described in which the processing unit 33 is connected to the indoor fan motor 13, this is not limited to this.

Although an example has been described in which the display unit 35 is a display on an external device, the present invention is not limited to this. The display unit 35 may be a display that is disposed on the outside of the housing 14 of the indoor unit 10 and connected to the processing unit 33. Furthermore, the display unit 35 is not limited to a display, and may be an LED that lights up depending on the result of the determination of a flammable refrigerant leak.

Although the display unit 35 is a display, the present invention is not limited to this. For example, the display unit 35 is an alarm unit that notifies the result of the flammable refrigerant leakage determination, and a control circuit that controls the alarm unit. The alarm unit may notify the result of the leakage determination by emitting a sound. For example, when the processing unit 33 determines that a flammable refrigerant is leaking, the processing unit 33 transmits a signal to the control circuit of the display unit 35. When the control circuit receives a signal from the processing unit 33, it makes the alarm unit sound. The alarm unit is disposed in a position where it can be heard by the user of the air conditioner 1. For example, the alarm unit is disposed outside the housing 14 of the indoor unit 10. Even with this configuration, the user of the air conditioner 1 can be notified of the result of the flammable refrigerant leakage determination, and the safety of the air conditioner 1 can be improved.

Although an example in which the first electrical component 30 is disposed inside the housing 14 of the indoor unit 10 has been described, this is not limiting. For example, as in Modification 1 described below, the first electrical component 30 may be disposed on the outside of the indoor unit 10 at a position higher than the first heat exchanger 11.

(Variation 1)
Fig. 7 is a schematic diagram of the indoor unit 10 of the modified example 1. As shown in Fig. 7, the first electrical component 30 is disposed on the upper surface of the housing 14, outside the housing 14 of the indoor unit 10. The first electrical component 30 is disposed on the other end P2 side of the first heat exchanger 11 on the upper surface of the housing 14.

The first electrical component 30 may be covered with a cover that protects the electronic components of the first electrical component 30. The first electrical component 30 may have wiring that is connected to the indoor fan motor 13. The wiring may pass through the housing 14.

With this configuration, the outer wall of the housing 14 is positioned between the first electrical component 30 and the brazed portion 16. This prevents flammable refrigerant leaking from the brazed portion 16 inside the housing 14 from reaching the first electrical component 30, and further prevents sparks and the like generated by the first electrical component 30 from becoming a source of ignition.

Although an example in which the first electrical component 30 is disposed on the other end P2 side of the first heat exchanger 11 has been described, this is not limiting. The first electrical component 30 may be disposed on the other end P2 side of the first heat exchanger 11 from near the center of the first heat exchanger 11.

(Embodiment 2)
An air conditioner 1A according to a second embodiment of the present disclosure will be described. Note that in the second embodiment, differences from the first embodiment will be mainly described. In the second embodiment, configurations that are the same as or equivalent to those in the first embodiment will be described with the same reference numerals. Also, in the second embodiment, descriptions that overlap with the first embodiment will be omitted.

Figure 8 is a schematic diagram of the internal structure of indoor unit 10A according to embodiment 2 of the present disclosure. For convenience, some components of air conditioner 1A, including sensor 17, are omitted.

Embodiment 2 differs from embodiment 1 in that indoor unit 10A has a partition wall 18. In other respects than those described above, air conditioner 1A according to embodiment 2 has a similar structure to air conditioner 1.

The isolation wall 18 functions to divide the interior of the housing 14. In the second embodiment, the isolation wall 18 is disposed within the housing 14 and divides the interior of the housing 14 into a first space R1 and a second space R2. The outer periphery of the isolation wall 18 is in contact with the inner wall of the housing 14. The isolation wall 18 extends from the inner wall of the front side of the housing 14, contacting and following the upper and lower surfaces of the housing 14, to the inner wall of the rear side of the housing 14.

Here, the end of the housing 14 on one end P1 side of the first heat exchanger 11 is the first end Q1, and the end of the housing 14 on the other end P2 side is the second end Q2. The first space R1 is defined by the partition wall 18 and the inner wall of the housing 14 on the second end Q2 side. On the other hand, the second space R2 is defined by the partition wall 18 and the inner wall of the housing 14 on the first end Q1 side. The first electrical component 30 and the indoor fan motor 13 are arranged in the first space R1, and the brazed portion 16 is arranged in the second space R2. In other words, the partition wall 18 is arranged between the first electrical component 30 and the indoor fan motor 13 and the brazed portion 16. With this configuration, the partition wall 18 can suppress the movement of flammable refrigerant leaking from the brazed portion 16 from the second space R2 to the first space R1, thereby improving the safety of the air conditioner 1A.

As shown in FIG. 8, the isolation wall 18 is disposed on the other end P2 side of the first heat exchanger 11, and the first heat exchanger 11 is disposed in the second space R2. The isolation wall 18 may be disposed away from the first heat exchanger 11 so as to have a gap between the isolation wall 18 and the first heat exchanger 11.

The structure of the isolation wall 18 will be explained in more detail using Figure 9.

Figure 9 is a schematic diagram of the isolation wall 18.

As shown in FIG. 9, the isolation wall 18 is a plate-shaped member. The isolation wall 18 may be a plate-shaped member having a thickness of 3 millimeters or more.

The upper and lower parts of the isolation wall 18 are made of different materials. The upper part of the isolation wall 18 is made of a material having multiple openings. On the other hand, a through hole may be formed in the lower part of the isolation wall 18. The shaft of the indoor fan motor 13, which is connected to the rotating shaft of the indoor fan 12, penetrates and closes the through hole. With this configuration, air can move from the first space R1 to the second space R2, while the movement of the flammable refrigerant, which is heavier than air, is suppressed. For example, the upper part of the isolation wall 18 is made of a mesh member 19 having multiple through holes formed therein.

The interval between the openings formed by the mesh member 19 may be equal to or less than the quenching distance D1 of the flammable refrigerant. The quenching distance D1 according to the electric charge spark method is calculated by the following formula (1) using the minimum energy E of the flammable refrigerant.
D1=0.35E/2...(1)
The minimum energy E is the energy required for a flammable refrigerant to be ignited by an electric spark. For example, when the flammable refrigerant is propane, the minimum energy of propane is 0.3 mJ or more and 0.7 mJ or less. Therefore, the quenching distance D1 of propane is 2 mm. In order to suppress the flame propagation of propane, the spacing between the openings of the mesh member 19 may be set to 2 mm or less.

The mesh member 19 is made of metal. The mesh member 19 is made of, for example, steel. The lower part of the partition wall 18 may also be made of metal. On the other hand, the lower part of the partition wall 18 may be made of a resin such as plastic. This structure can reduce the weight of the indoor unit 10A.

Furthermore, the upper part of the isolation wall 18 may be formed of a punched metal instead of the mesh member 19. The punched metal is a metal plate member having a plurality of openings formed by press working using a die. The shape of the openings may be circular. Furthermore, the diameter of the openings may be equal to or smaller than the quenching diameter D2 of the flammable refrigerant. The quenching diameter D2 according to the electric charge spark method is calculated by the following formula (2) using the quenching distance D1.
D2=D1/0.7...(2)
The quenching diameter D2 of propane is 3 mm. In order to suppress the flame propagation of propane, the diameter of the opening of the punched metal may be set to 3 mm or less.

[effect]
According to the air conditioner 1A according to the second embodiment, the following effects can be achieved.

The air conditioner 1A uses a flammable refrigerant. The air conditioner 1A includes a housing 14, a first heat exchanger 11, an indoor fan 12, an indoor fan motor 13, a first electrical component 30, and an isolation wall 18. The housing 14 constitutes the exterior of the indoor unit 10A. The first heat exchanger 11 is housed within the housing 14. The indoor fan 12 is disposed inside the first heat exchanger 11. The indoor fan motor 13 is connected to the indoor fan 12. The first electrical component 30 includes a control circuit that comprehensively controls the indoor unit 10A. The isolation wall 18 is disposed within the housing 14 and divides the interior of the housing 14 into a first space R1 and a second space R2. The first heat exchanger 11 includes a plurality of heat transfer tubes 15 and a brazed portion. The heat transfer tubes 15 extend from one end P1 of the first heat exchanger 11 to the other end P2 and turn back, and a flammable refrigerant flows inside them. The brazed portion is brazed to the heat transfer tubes 15 on the one end P1 side of the first heat exchanger 11. The first electrical component 30 and the indoor fan motor 13 are arranged in the first space R1, and the brazed portion 16 is arranged in the second space R2.

With this configuration, inside the housing 14, the isolation wall 18 can prevent the flammable refrigerant leaking from the brazed portion 16 from reaching the first electrical component 30 and the indoor fan motor 13. Sparks and the like generated by the first electrical component 30 and the indoor fan motor 13 can be prevented from becoming a source of ignition. This prevents the flammable refrigerant from igniting, improving the safety of the air conditioner 1A that uses a flammable refrigerant.

The isolation wall 18 is arranged on the other end P2 side of the first heat exchanger 11. The first heat exchanger 11 is arranged in the second space R2.

This configuration prevents the flammable refrigerant from reaching the first electrical component 30 and the indoor fan motor 13 even if the flammable refrigerant leaks from the heat transfer tube 15.

Multiple openings are formed in the upper part of the isolation wall 18.

With this configuration, even if a flammable refrigerant explodes in the first space R1, the pressure of the explosion can be released to the outside of the first space R1 through the opening. This prevents damage to the housing 14 that forms the first space R1, and reduces damage to people in the room.

The upper part of the isolation wall 18 is formed of a mesh member 19.

With this configuration, even if a flammable refrigerant causes an explosion in the first space R1, the pressure of the explosion can be further released to the outside of the first space R1 through the mesh member 19.

The mesh member 19 is made of metal.

This configuration improves the durability of the upper part of the isolation wall 18.

The spacing between the openings formed by the mesh member 19 is equal to or less than the quenching distance D1 of the flammable refrigerant.

This configuration makes it possible to suppress flame propagation even if an explosion occurs in the first space R1.

The indoor fan motor 13 has a shaft that is connected to the rotating shaft of the indoor fan 12. A through hole through which the shaft passes is formed in the lower part of the isolation wall 18.

This configuration allows the indoor fan 12 to be driven while the indoor fan motor 13 is placed in the first space R1 to improve the safety of the air conditioner 1A that uses a flammable refrigerant.

In the second embodiment, an example in which the upper part of the partition wall 18 is formed from the mesh member 19 has been described, but this is not limiting. For example, the partition wall 18 may be formed from a member that does not have any openings in its entirety. Also, as in the second modification example described below, a single opening may be formed in the upper part of the partition wall 18.

(Variation 2)
Fig. 10 is a schematic diagram of the internal structure of an indoor unit 10A of Modification 2. As shown in Fig. 10, the upper part of the partition wall 18 is formed of a material having one opening. The opening may have a height of ⅙ to ⅓ of the height of the partition wall 18.

Even with this configuration, if a flammable refrigerant causes an explosion in the first space R1, the pressure of the explosion can be released to the outside of the first space R1 through the opening.

Although an example has been described in which the upper portion of the isolation wall 18 is formed from a material having one opening, this is not limiting. Instead of being formed from a material having an opening, the isolation wall 18 may not contact the upper surface of the housing 14, and a gap may be formed between the upper end of the isolation wall 18 and the upper surface of the housing 14. The height of the gap may be 1/6 or more and 1/3 or less than the height of the isolation wall 18.

In the second embodiment, an example in which the partition wall 18 is disposed on the other end P2 side of the first heat exchanger 11 has been described, but this is not limiting. For example, as in Modifications 3 and 4 described below, the partition wall 18 may be disposed on one end P1 side of the first heat exchanger 11.

(Variation 3)
Fig. 11 is a schematic diagram of the internal structure of the indoor unit 10A of Modification 3. As shown in Fig. 11, the partition wall 18 is disposed in the first heat exchanger 11 on the inner side of the brazed portion 16. For example, the partition wall 18 is disposed on one end P1 side of the first heat exchanger 11 so that the heat transfer tube 15 penetrates the partition wall 18. The first electrical component 30, the indoor fan motor 13, and a part of the first heat exchanger 11 excluding the brazed portion 16 are disposed in the first space R1. A part of the heat transfer tube 15 and the brazed portion 16 are disposed in the second space R2.

Even with this configuration, the isolation wall 18 can prevent flammable refrigerant leaking from the brazed portion 16 from reaching the first electrical component 30 and the indoor fan motor 13. In addition, since the leaked flammable refrigerant does not flow out from the second space R2, it becomes easy to detect the leaked flammable refrigerant using a sensor or the like arranged in the second space R2.

The isolation wall 18 may also serve as a fin for the first heat exchanger 11. The isolation wall 18 may also serve as a flange for positioning the first heat exchanger 11 within the housing 14.

In the second embodiment, the first electrical component 30 and the indoor fan motor 13 are disposed on the other end P2 side of the first heat exchanger 11, but the present invention is not limited to this. For example, as in the fourth modified example described below, the first electrical component 30 and the indoor fan motor 13 may be disposed on the one end P1 side of the first heat exchanger 11.

(Variation 4)
Fig. 12 is a schematic diagram of the internal structure of the indoor unit 10A of the fourth modified example. As shown in Fig. 12, the partition wall 18 is disposed on one end P1 side of the first heat exchanger 11. In this case, the first space R1 is defined by the partition wall 18 and the inner wall of the housing 14 on the first end Q1 side. On the other hand, the second space R2 is defined by the partition wall 18 and the inner wall of the housing 14 on the second end Q2 side. The first electrical component 30 and the indoor fan motor 13 are disposed in the first space R1. The first heat exchanger 11 is disposed in the second space R2.

Even with this configuration, the isolation wall 18 can prevent flammable refrigerant leaking from the brazed portion 16 from reaching the first electrical component 30 and the indoor fan motor 13.

Although the present disclosure has been fully described in connection with the preferred embodiment with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.

The air conditioner disclosed herein is useful as an air conditioner because it can improve the safety of air conditioners that use flammable refrigerants.

REFERENCE SIGNS LIST 1 Air conditioner 10 Indoor unit 11 First heat exchanger 12 Indoor fan 13 Indoor fan motor 14 Housing 15 Heat transfer tube 16 Brazed portion 17 Sensor 18 Isolation wall 19 Mesh member 20 Outdoor unit 21 Second heat exchanger 22 Outdoor fan 23 Compressor 24 Expansion mechanism 25 Four-way valve 30 First electrical component 31 First electrical wiring 32 Power supply wiring 33 Processing unit 34 Communication unit 35 Display unit 40 Second electrical component 41 Second electrical wiring 50 Refrigerant piping 51 Flow direction P1 One end P2 Other end R1 First space R2 Second space

Claims (8)

An air conditioner using a flammable refrigerant,
A housing that constitutes the exterior of the indoor unit;
A heat exchanger housed within the housing; and
A fan disposed inside the heat exchanger;
a fan motor connected to the fan;
An electrical component including a control circuit that comprehensively controls the indoor unit;
a partition wall disposed within the housing and partitioning the interior of the housing into a first space and a second space;
Equipped with
The heat exchanger includes:
A plurality of heat transfer tubes extending from one end to the other end of the heat exchanger and turning back, through which the flammable refrigerant flows;
a brazing portion brazed to the heat transfer tubes at the one end of the heat exchanger;
Equipped with
the electrical equipment and the fan motor are disposed in the first space, and the brazed portion is disposed in the second space;
The air conditioner, wherein one or more openings are formed in an upper portion of the partition wall. the fan motor has a shaft connected to a rotation axis of the fan,
The air conditioner according to claim 1 , wherein a through hole through which the shaft passes is formed in a lower portion of the partition wall. The partition wall is disposed on the other end side of the heat exchanger,
The air conditioner according to claim 1 or 2, wherein the heat exchanger is disposed in the second space. The partition wall is disposed on the one end side of the heat exchanger,
The air conditioner according to claim 1 or 2, wherein the heat exchanger is disposed in the second space. The air conditioner according to claim 1 or 2, wherein the partition wall is disposed on the heat exchanger inside the brazed portion. The air conditioner according to claim 1 or 2, wherein the upper part of the partition wall is formed of a mesh member. The air conditioner according to claim 6, wherein the mesh member is made of metal. The air conditioner according to claim 6 or 7, wherein the spacing between the openings formed by the mesh member is equal to or less than the quenching distance of the flammable refrigerant.

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