The present disclosure relates to an air conditioner.
Conventionally, for example, as disclosed in Patent Literature 1 (JP 2015-94512 A), an air conditioner using a flammable refrigerant is known.
An air conditioner according to one or more embodiments includes a heat exchanger, a fan, a heating part or an electric apparatus, a casing, and an opening and closing part. A heat exchanger exchanges heat between air sent to an air conditioning target space and a flammable refrigerant. A fan generates an air flow in the heat exchanger. The heating part heats the air sent to the air conditioning target space. The electric apparatus may cause electric discharge. The casing has an arrangement space in which the heat exchanger, the fan, and the heating part or the electric apparatus are disposed, and has an opening that communicates the arrangement space with outdoors. The opening and closing part opens and closes the opening. The opening and closing part closes the opening when the fan is driven, and opens the opening when the fan is stopped.
(1) Overall Configuration
As shown in
(2) Detailed Configurations
(2-1) Configuration of Air Conditioner
The air conditioner 1 includes a casing 10. The casing 10 of the air conditioner 1 shown in
The air conditioner 1 includes a refrigerant circuit 20 through which a refrigerant flows, a first fan 31, a second fan 32, a furnace burner unit 40, a control unit 50, and an opening and closing part 60. The refrigerant circuit 20 includes a compressor 21, a condenser 22, an expansion valve 23, an evaporator 24, and an accumulator 25. The evaporator 24 is a heat exchanger that exchanges heat between air sent to the air conditioning target space and a flammable refrigerant. The first fan 31 is a fan that generates an air flow in the evaporator 24 which is a heat exchanger.
The refrigerant circuit 20 achieves a vapor compression refrigeration cycle. Therefore, the refrigerant circulates in the refrigerant circuit 20. A flammable refrigerant is used in the refrigerant circuit 20. Examples of the flammable refrigerant include an A2L refrigerant. Examples of the A2L refrigerant include an R32 refrigerant and an R454B refrigerant.
During cooling, a gas refrigerant compressed by the compressor 21 of the refrigerant circuit 20 is sent to the condenser 22. The refrigerant radiates heat to outdoor air in the condenser 22, and is sent to the expansion valve 23 through a refrigerant pipe. In the expansion valve 23, the refrigerant is expanded and decompressed. The refrigerant decompressed in the expansion valve 23 is sent to the evaporator 24. The low-temperature and low-pressure refrigerant sent from the expansion valve 23 exchanges heat in the evaporator 24 to take heat from the air passing through the evaporator 24. The air exchanging heat in the evaporator 24 is air RA returning from the building 100 through the return air duct 3. The air removed of heat and cooled by the evaporator 24 is supplied to the building 100 through the air supply duct 2. A gas refrigerant or a gas-liquid two-phase refrigerant having exchanged heat in the evaporator 24 flows through the accumulator 25 and is sucked to the compressor 21.
During heating, the air warmed by the furnace burner unit 40 is supplied to the building 100 through the air supply duct 2. The air RA returning from the building 100 through the return air duct 3 is sent to the furnace burner unit 40 by the first fan 31.
The first chamber R1 is connected to the return air duct 3. The evaporator 24 is disposed between the first chamber R1 and the second chamber R2. The air having passed through the evaporator 24 from the first chamber R1 enters the second chamber R2. In the second chamber R2, the first fan 31 is disposed. A suction port 31a (see
In the fourth chamber R4, the compressor 21, the accumulator 25, and the control unit 50 are disposed. In the fifth chamber R5, the condenser 22 and the second fan 32 are disposed. Outdoor air is sucked into the fifth chamber R5 by the second fan 32, and the air passing through the condenser 22 is discharged from the fifth chamber R5 to outdoors. Therefore, even when the refrigerant leaks from the condenser 22 in the fifth chamber R5, the risk that the refrigerant staying in the fifth chamber R5 burns is extremely small. Arrows shown in the fifth chamber R5 indicate flows of air sucked from outdoors and air discharged to outdoors by the second fan 32.
Since the refrigerant has a density higher than a density of air, the refrigerant tends to fall downward in the air and accumulate at a low position due to a difference in gravity applied to the refrigerant and the air. When the air conditioner 1 is installed on the ground, the refrigerant leaking at or around the evaporator 24 tends to stay in the air supply duct 2 and the return air duct 3 and in the casing 10, unlike when the air conditioner 1 is installed on the rooftop. The volume in the air supply duct 2, the return air duct 3, and the casing 10 is smaller than the volume in the interior of the building 100. Therefore, as compared with a case where the air conditioner 1 is installed on the rooftop, in a case where the air conditioner 1 is installed on the ground or the like, the refrigerant is concentrated in the casing 10, the air supply duct 2, and the return air duct 3, and thus the risk that the concentration of the leaking refrigerant exceeds a lower flammability limit concentration increases.
When the refrigerant leaks at or around the evaporator 24, the leaking refrigerant first accumulates in the first chamber R1, the second chamber R2, and the return air duct 3. The refrigerant accumulated in the first chamber R1, the second chamber R2, and the return air duct 3 then leaks to the third chamber R3 in which the furnace burner unit 40 is provided, the fourth chamber R4 in which the compressor 21, the control unit 50, and the like are provided, and the fifth chamber R5 in which the condenser 22 is provided, through a small gap opened in a partition plate separating the first to fifth chambers R1 to R5, the first fan 31, and the like.
In the casing 10, a heating part (i.e., heater) or an electric apparatus that can be possibly an ignition source of the refrigerant exceeding the combustion lower limit concentration is disposed. The heating part is a component having a higher temperature than the other components during operation. The electric apparatus is a device that can possibly cause electric discharge during operation. In other words, the electric apparatus is a device can possibly make a spark fly. Examples of the heating part include the furnace burner unit 40 and an electric heater (not shown) to be described later. Examples of the electric apparatus that can possibly cause electric discharge include an electromagnetic relay 51 and an electrostatic precipitator (not shown). Although there are many components other than the electromagnetic relay 51 in the control unit 50, the components other than the electromagnetic relay 51 are not shown in
The first chamber R1 is provided with an opening and closing part 60 for preventing a concentration of a refrigerant leaking from exceeding the combustion lower limit concentration when the refrigerant leaks at or around the evaporator 24. The opening and closing part 60 opens and closes an opening that communicates from the first chamber R1 to outside of the casing 10.
(2-2) Opening and Closing Part 60
As shown in
Specifically, a spring 63 is provided between the lid 61 and the casing 10 so that the lid 61 is supported by the spring 63 to open the opening 19 of the opening and closing part 60 when the first fan 31 is stopped.
H=K×C=W×g×tan β (1)
In
When the lid 61 is closed, the lid 61 is pressed against the side plate 11 of the casing 10 by the air pressure difference ΔP between the inside and the outside. In other words, the air pressure difference ΔP between the inside and the outside overcomes a repulsive force of the spring 63, and the lid 61 closes the opening 19. In order for the lid 61 to keep closing the opening 19, a pressing force Fp generated by the air pressure difference ΔP is required to be larger than a repulsive force Fs of the spring 63. When an area of the opening 19 is Ar [m2], the air pressure difference is ΔP [Pa], the number of springs is n, and a contraction margin of the spring 63 from the free state is (B+C) [mm] in a state where the lid 61 is closed, the following formulas (2), (3), and (4) are satisfied.
Fp=ΔP×Ar (2)
Fs=n×K×(B+C) (3)
Fp>Fs (4)
The lid 61 may include metal, for example, in order to increase the weight of the lid 61. The lid 61 includes iron, for example.
(3) Modifications
(3-1) Modification A
In the above embodiments, the case has been described where a refrigerant flow direction in the refrigerant circuit 20 is constant and the condenser 22 and the evaporator 24 are not switched. However, the refrigerant circuit used in the air conditioner 1 may be configured such that a refrigerant flow direction is switched by, for example, a four-way valve. In the case where the refrigerant flow is switched as described above, the evaporator 24 can be switched to operate as a condenser, and the condenser 22 can be switched to operate as an evaporator.
(3-2) Modification B
In the above embodiments, the case has been described where the spring 63 is used as a member that supports the lid 61 when the opening and closing part 60 is open. Alternatively, the member supporting the lid 61 may be an elastic body other than the spring 63. Examples of the elastic body include rubber.
(3-3) Modification C
In the above embodiments, the case has been described where a negative pressure generated by the first fan 31 is used for opening and closing the opening and closing part 60. However, a positive pressure generated by the first fan 31 may be used to open and close the opening and closing part 60. For example, as shown in
(3-4) Modification D
In the above embodiments, the lid is supported by the spring 63. However, as shown in
When the first fan 31 is driven, air is sucked into the casing 10 through behind the lid 61 as shown in
(3-5) Modification E
The opening and closing part 60 according to the above embodiments opens and closes the lid 61 by using a change in the air pressure in the casing 10 generated by the first fan 31. However, the lid 61 may be opened and closed by using power other than the change in the air pressure in the casing 10.
(3-6) Modification F
In the above embodiments, the case where the lid 61 rotationally moves when the opening and closing part 60 opens and closes the opening 19 has been described as an example. However, the movement of the lid 61 when the opening 19 is opened and closed is not limited to the rotational movement. For example, as shown in
The opening and closing part 60 switches between a state in which a current flows to the electromagnet 80 and a state in which the current does not flow to the electromagnet 80 to translate the lid 61 and open and close the lid 61. In the opening and closing part 60 in a state in which no current flows in the electromagnet 80, as shown in
(3-7) Modification G
In the above embodiments, the case has been described where supply air SA is warmed by the furnace burner unit 40. However, other heating means may be provided in the casing 10 instead of the furnace burner unit 40. Instead of the furnace burner unit 40, for example, an electric heater may be provided in the third chamber R3 of the casing 10. The electric heater is a heating part.
(3-8) Modification H
In the above embodiments, the case has been described where the opening and closing part 60 is configured to open only when the first fan 31 is stopped. However, the opening and closing part 60 may be configured to open not only when the first fan 31 is stopped but also when the first fan 31 is driven and the following preset specific condition is satisfied. The specific condition for opening the opening and closing part 60 is, for example, a condition that energy can be saved by opening the opening and closing part 60. The opening and closing part 60 may be configured to be opened when the indoor temperature is higher than the outdoor temperature, for example, in a cooling operation mode of the air conditioner 1. The opening and closing part 60 of Modification H is configured to be always opened when the first fan 31 is stopped, and in addition, to be opened when the above-described specific condition is satisfied.
(4) Characteristics
(4-1)
In the air conditioner 1 described above, there is a possibility that the refrigerant used in the evaporator 24 which is a heat exchanger leaks when the first fan 31 is stopped. However, since the opening and closing part 60 opens the opening 19 when the first fan 31 is stopped, the refrigerant can be released from the second chamber R2, the third chamber R3, and the fourth chamber R4, which are the arrangement space of the casing 10, to the outdoors through the opening 19. Since the air conditioner 1 has a simple configuration, sufficient safety can be secured at low cost.
In other words, the opening and closing part 60 shown in
The lid 61 is a part of a wall of the first chamber R1 in the casing 10 that has a negative pressure when the first fan 31 is driven. The lid 61 is attached to the opening 19 of the casing 10 by the hinge 62. Therefore, in the lid opening and closing device, when the first fan 31 is driven, the first chamber R1 has a negative pressure, and thus a force generated at the lid 61 exceeds a force generated by the spring 63. Then, the lid 61 is brought into close contact with the casing 10 to automatically close the opening 19. In the lid opening and closing device, when the first fan 31 is stopped, the force generated at the lid 61 due to the difference between the air pressures inside and outside the casing is reduced, and the lid 61 is separated from the opening 19 by the force generated by the spring 63, and the opening 19 is automatically opened.
In other words, the opening and closing part 60 shown in
In the lid opening and closing device, in a state where the first fan 31 is stopped, no force is generated in the air cylinder 70 (actuator), and the lid 61 is merely supported by the hinge 62, the lid 61 is separated from the casing 10 by the weight of the lid 61, and the opening 19 is automatically opened. In the lid opening and closing device, when the first fan 31 is driven, the third chamber R3 and the air cylinder 70 (actuator) have a positive pressure, and the force with which the piston 72 presses the lid 61 exceeds the force to open the lid 61 by the weight of the lid 61, and the lid 61 is brought into close contact with the casing 10 to automatically close the opening 19.
In other words, the opening and closing part 60 shown in
The lid 61 is a part of a wall of the first chamber R1 in the casing 10 that has a negative pressure when the first fan 31 is driven. In the lid opening and closing device, when the first fan 31 is driven, the first chamber R1 has a negative pressure, and thus the force generated at the lid 61 exceeds the force to open the lid 61 by the weight of the lid 61. Then, the lid 61 is brought into close contact with the casing 10 to automatically close the opening 19. In the lid opening and closing device, when the first fan 31 is stopped, the force generated at the lid 61 due to the difference between the air pressures inside and outside the casing is reduced, and the lid 61 is separated from the opening 19 by the force generated by the weight of the lid 61, and the casing 10 is automatically opened.
In other words, the opening and closing part 60 shown in
In the lid opening and closing device, when a current does not flow through the electromagnet 80 (actuator), the lid 61 is merely supported by the hinge 62, and the lid 61 is brought into close contact with the casing 10 by the weight of the lid 61 to automatically close the opening 19. In the lid opening and closing device, when a current flows through the electromagnet 80 (actuator), a force by which the electromagnet 80 (actuator) attracts the lid 61 exceeds a force to close the lid 61 by the weight of the lid 61, and thus the lid 61 is separated and the opening 19 is automatically opened.
In other words, the opening and closing part 60 shown in
In the lid opening and closing device, when no current flows through the electromagnet 80 (actuator), the opening 19 of the casing 10 and the slit 61a of the lid 61 overlap each other in a state where the lid 61 is supported by an elastic force of the spring 63 (elastic body), and the opening 19 is automatically opened. In the lid opening and closing device, when a current flows through the electromagnet 80 (actuator), a force by which the electromagnet 80 (actuator) attracts the lid 61 exceeds the elastic force of the spring 63 (elastic body), the slit 61a of the sliding lid 61 does not overlap the opening 19 of the casing 10, and thus the opening 19 is automatically closed.
(4-2)
In the air conditioner 1 described above, the negative pressure or the positive pressure generated by driving of the first fan 31 is used for opening and closing the lid 61 of the opening and closing part 60. Therefore, it is not necessary to newly provide a power source for opening and closing the lid 61. As a result, the air conditioner 1 including the opening and closing part 60 can be provided at low cost.
(4-3)
In the air conditioner 1 according to the above embodiments, a biasing force of the spring 63 which is an elastic body assists the movement of the lid 61, and thus reliability of an opening and closing operation of the lid 61 is improved.
(4-4)
In the air conditioner 1, the opening and closing operation of the opening 19 by the lid 61 is performed by the rotational movement or the translation of the lid 61. The rotational movement of the lid 61 can be achieved by the hinge 62, and the translation of the lid 61 can be achieved by sliding the lid 61. Therefore, the opening and closing operation of the lid 61 can be easily achieved.
(4-5)
When the movement of the lid 61 is assisted by the weight of the lid 61 in the air conditioner 1, it is possible to improve the reliability of the opening and closing operation of the lid 61. For example, in the opening and closing part 60 shown in
(4-6)
The air cylinder 70 is used as an actuator in the opening and closing part 60 shown in
(4-7)
Since the air conditioner 1 according to the above embodiments includes the filter 67 that covers the opening 19, the filter 67 prevents entry of foreign matter such as an insect.
(4-8)
The air conditioner 1 can release a flammable refrigerant from the casing 10 to the outdoors through the opening 19 to prevent the leaking refrigerant from being accumulated in the casing 10 and burning even when the furnace burner unit 40 including a burner, the electric heater, and the electromagnetic relay 51 generate heat.
Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the disclosure should be limited only by the attached claims.
Patent Literature 1: JP 2015-94512 A
Number | Date | Country | Kind |
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2020-200012 | Dec 2020 | JP | national |
This is a continuation application of International Patent Application No. PCT/JP2021/043421, filed on Nov. 26, 2021, and claims priority to Japanese Patent Application No. 2020-200012, filed on Dec. 2, 2020. The contents of these priority applications are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2021/043421 | Nov 2021 | US |
Child | 18323020 | US |