JP6915959B2 - Indoor unit equipped with a discharge device - Google Patents

Description

The present invention relates to an indoor unit provided with a discharge device. More specifically, the present invention relates to an indoor unit provided with a discharge device and using a slightly flammable or flammable refrigerant having a specific density larger than that of air.

In recent years, R32 refrigerants having a low global warming potential have been increasingly adopted in air conditioners that cool and heat indoors by a vapor compression refrigeration cycle. However, since the R32 refrigerant has a slight flammability (slight flammability), it is necessary to be careful in its handling when using it.

On the other hand, in addition to the conventional cooling and heating functions, an indoor unit having various functions such as dust collection, sterilization, and deodorization utilizing the discharge phenomenon by the discharge device has been proposed. When a flammable refrigerant is used in an indoor unit equipped with such a discharge device, the flammable refrigerant leaks from parts constituting the refrigeration cycle such as a heat exchanger and a refrigerant pipe, and the leaked refrigerant leaks to the high voltage part of the discharge device. Contact may cause ignition due to discharge energy.

Therefore, in order to avoid such a risk of ignition, as shown in FIG. 5, the discharge device 50 is arranged above the parts constituting the refrigeration cycle such as the heat exchanger 51 and the refrigerant pipe, and air is provided. Even if a refrigerant having a higher specific gravity leaks from the heat exchanger 51, the refrigerant pipe, or the like, an air conditioner 52 that prevents the leaked refrigerant from reaching the high voltage portion of the discharge device 50 has been proposed (Patented). Reference 1). In FIG. 5, reference numeral 53 is an air filter arranged on the suction side of the indoor fan 54, and reference numeral 55 is a gas sensor for detecting the leakage of the refrigerant.

Japanese Unexamined Patent Publication No. 2013-64524

However, the technique described in Patent Document 1 can be applied only to an indoor unit of a type in which an air suction port is arranged on the side or above of a casing, and its applicable range is limited. In a ceiling-embedded type or ceiling-suspended indoor unit, an air suction port is generally formed on the lower surface of the casing. In this case, a discharge device such as an electrostatic collector is arranged on the suction side of the indoor fan. Therefore, if the refrigerant leaks from the heat exchanger or the like located above the discharge device and the leaked refrigerant having a flammable concentration comes into contact with the high voltage portion of the discharge device, the leaked refrigerant may ignite.

The present invention has been made in view of such circumstances, and is an indoor unit in which a discharge device is arranged below a portion constituting a refrigeration cycle, in which a leaking refrigerant having a flammable concentration is a high voltage portion of the discharge device. It is an object of the present invention to provide an indoor unit capable of preventing contact with.

(1) The indoor unit provided with the discharge device of the present invention (hereinafter, also simply referred to as “indoor unit”) includes a refrigerating cycle component including a heat exchanger and a refrigerant pipe, an indoor fan, and the refrigerating cycle component. An indoor unit that includes a discharge device arranged below and a control unit that controls the operation of the indoor fan and the discharge device, and uses a slightly flammable or flammable refrigerant having a specific gravity larger than that of air.
The control unit starts or stops the operation of the discharge device after the first predetermined time has elapsed from the start of the operation of the indoor fan, or during the operation of the indoor fan or the operation stop of the indoor fan. This is performed before the second predetermined time elapses from the instruction.

In the indoor unit of the present invention, after the first predetermined time has elapsed since the control unit started the operation of the indoor fan, or during the operation of the indoor fan or from the instruction to stop the operation of the indoor fan, the second predetermined time. The operation of the discharge device is started or stopped before the elapse of. In other words, when the discharge device is operating, the indoor fan is in a constant operation. Therefore, in the unlikely event that the indoor unit is stopped, the refrigeration cycle configuration includes the heat exchanger and the refrigerant piping. Even if the refrigerant leaks from the unit, the leaked refrigerant is diffused by the air flow generated by driving the indoor fan, so that when the discharge device starts operation, it stays near the high voltage part of the discharge device. Not done. Therefore, it is possible to avoid the risk that the leaked refrigerant having a flammable concentration comes into contact with the high voltage portion of the discharging device during operation and the leaked refrigerant is ignited. Further, even if the refrigerant leaks from the refrigerating cycle component during the operation of the indoor unit, the leaked refrigerant is diffused by the air flow generated by driving the indoor fan, so that the leaked refrigerant is located below the refrigerating cycle component. It hardly reaches the high voltage part of the arranged discharge device. As a result, it is possible to avoid the risk that the leaked refrigerant having a flammable concentration comes into contact with the high voltage portion of the discharging device during operation and the leaked refrigerant is ignited. The "state of constant operation" means a state in which the indoor fan is in normal operation, and a state in which the rotation speed is lower than in normal operation, but the leaking refrigerant can be diffused. It is an operating state that can generate an air flow.

(2) In the indoor unit of the above (1), the first predetermined time is defined as the time when the rotation speed of the indoor fan reaches the predetermined rotation speed.
The second predetermined time can be set as a time during which the rotation speed of the indoor fan decreases from the rotation speed during operation to the predetermined rotation speed. In this case, the control unit starts or stops the operation of the discharge device when the rotation speed of the indoor fan exceeds a predetermined rotation speed, so that even if the refrigerant leaks from the refrigeration cycle component, the leaked refrigerant is released. It can be diffused, and it is possible to prevent the leaking refrigerant having a flammable concentration from coming into contact with the high voltage portion of the discharge device arranged below the refrigeration cycle component.

(3) In the indoor unit of the above (2), the predetermined rotation speed can be set as the minimum rotation speed of the indoor fan. In this case, if the indoor fan is operated at the minimum rotation speed or higher, even if the refrigerant leaks from the refrigeration cycle component, the leaked refrigerant can be diffused, and the leaked refrigerant having a flammable concentration is below the refrigeration cycle component. It is possible to prevent contact with the high voltage portion of the discharge device arranged in.

According to the indoor unit of the present invention, in the indoor unit in which the discharge device is arranged below the portion constituting the refrigeration cycle, it is possible to prevent the leaking refrigerant having a flammable concentration from coming into contact with the high voltage portion of the discharge device. ..

It is a perspective explanatory drawing of one Embodiment of the indoor unit of this invention. It is sectional drawing explanatory view of the indoor unit shown in FIG. It is a time flow showing the relationship between the on / off operation of the indoor unit, the rotation speed of the indoor fan, and the on / off of the discharge device. It is sectional drawing explanatory drawing of another embodiment of the indoor unit of this invention. It is sectional drawing of the conventional indoor unit.

Hereinafter, embodiments of the indoor unit of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective explanatory view of the indoor unit 1 according to the embodiment of the present invention, and FIG. 2 is a cross-sectional explanatory view of the indoor unit 1 shown in FIG.

The indoor unit 1 is a ceiling-embedded indoor unit, and includes a casing 2 for accommodating various elements such as an indoor fan and a heat exchanger, which will be described later, and a decorative panel 3. The casing 2 is formed of a box-shaped body having an open lower end surface, and is arranged in an opening formed in the ceiling C as shown in FIG. The decorative panel 3 is made of a square plate, and a suction port 4 for sucking air in the air conditioning chamber is formed in the center. Further, an elongated rectangular outlet 5 for blowing out harmonious air into the air conditioning chamber is formed around the suction port 4 so as to be along each side of the decorative panel 3.

Each outlet 5 is provided with a flap 5a for adjusting the wind direction of the harmonized air blown from the outlet 5 into the air conditioning chamber. The flap 5a can rotate about an axis along the longitudinal direction of the air outlet 5. The flap 5a can be rotated by a motor (not shown).

The suction port 4 of the decorative panel 3 has a suction grill 6 from the indoor side, a pre-filter 7 for removing relatively large dust in the indoor air sucked from the suction port 4, a discharge device 8, and a primary filter. 9 and the secondary filter 10 are arranged in this order.

As shown in FIG. 2, the discharge device 8 includes a counter electrode 11, an ionization line 12, and a streamer discharge electrode 13. The counter electrode 11 is made of a metal plate having a square wave-shaped cross section. The ionization wire 12 is made of a tungsten wire having a small diameter or the like, and is used as a discharge electrode. The streamer discharge electrode 13 is composed of an electrode rod 13a and a needle electrode 13b.
The counter electrode 11 and the ionization line 12 play a role of charging relatively small dust contained in the air that has passed through the prefilter 7. On the other hand, the counter electrode 11 and the streamer discharge electrode 13 play a role of generating so-called active species. Specifically, when a DC, AC, or pulsed discharge voltage is applied between the counter electrode 11 and the streamer discharge electrode 13, streamer discharge occurs between both electrodes, and low-temperature plasma is generated in the discharge field. This low-temperature plasma produces tagical species such as ions, ozone, and hydroxyl radicals, and active species such as cold forged molecules such as excited oxygen molecules and excited nitrogen molecules. These active species have a high energy level and have the ability to decompose and deodorize organic molecules such as ammonia and aldehydes contained in the air.

The primary filter 9 has an electrostatic filter, and a part of positively charged fine particles, odor molecules, and the like in the discharge device 8 is electrostatically adsorbed. Titanium dioxide is supported on the secondary filter 10, and viruses, bacteria, etc. that were not adsorbed by the primary filter 9 are adsorbed.

Inside the casing 2, the air in the air-conditioning room is sucked from the suction port 4 of the decorative panel 3, heat exchange is performed on the air, and then the harmonized air is blown out into the air-conditioning room from the air outlet 5 of the decorative panel 3. And a heat exchanger 15 arranged so as to surround the indoor fan 14. The indoor fan 14 has a motor 16 and an impeller 17.

The heat exchanger 15 is a cross-fin tube type heat exchanger formed by bending so as to surround the indoor fan 14. Below the heat exchanger 15, a drain pan 118 for receiving the drain generated by condensing the moisture in the air that exchanges heat with the heat exchanger 15 is arranged.
Further, in the casing 2, a control unit P for controlling the operation of the indoor fan 14 and the discharge device 8 is arranged.

The indoor unit 1 in the present embodiment uses an R32 refrigerant which is a slightly flammable or flammable refrigerant as the refrigerant. Further, the discharge device 8 is arranged below the refrigeration cycle component including the heat exchanger 15 and the refrigerant pipe. Since the R32 refrigerant has a higher specific gravity than air, if the refrigerant leaks from the refrigeration cycle component, the leaked refrigerant may come into contact with a high voltage portion such as the ionization line 12 in the discharge device 8. Then, when the leaked refrigerant having a flammable concentration comes into contact with the operating high voltage portion, the leaked refrigerant may ignite.

Therefore, in the indoor unit 1 according to the present embodiment, regarding the operation of the discharge device 8 and the indoor fan 14, a predetermined time (first predetermined time) has been set since the control unit P started the operation of the indoor fan 14. After a lapse of time, the operation of the discharge device 8 is started in a state where the rotation speed of the indoor fan 14 exceeds a predetermined rotation speed. Further, during the operation of the indoor fan 14, or before a predetermined time (second predetermined time) has elapsed from the operation stop instruction of the indoor fan 14 (for example, the instruction to stop the operation of the indoor unit 1 by remote control operation). The operation of the discharge device 8 is stopped when the rotation speed of the indoor fan 14 exceeds a predetermined rotation speed. In this way, since the rotation speed of the indoor fan 14 exceeds the predetermined rotation speed during the operation of the discharge device 8, the heat exchanger 15 and the refrigerant pipe are connected while the operation of the indoor unit 1 is stopped. Even if the refrigerant leaks from the refrigeration cycle component including the refrigerating cycle component and stays in the vicinity of the high voltage portion of the discharge device 8, the leaked refrigerant is diffused by the air flow generated by driving the indoor fan 14. When the rotation speed of the indoor fan 14 exceeds a predetermined rotation speed and the discharge device 8 starts operation, it no longer stays in the vicinity of the high voltage portion of the discharge device 8. Therefore, it is possible to avoid the risk that the leaked refrigerant having a flammable concentration comes into contact with the high voltage portion of the discharging device 8 during operation and the leaked refrigerant is ignited.

Further, even if the refrigerant leaks from the refrigeration cycle component during the operation of the indoor unit 1, the leaked refrigerant is diffused by the air flow generated by the indoor fan 14 being driven, so that the refrigeration cycle component It hardly reaches the high voltage part of the discharge device 8 arranged below. As a result, it is possible to avoid the risk that the leaked refrigerant having a flammable concentration comes into contact with the high voltage portion of the discharging device 8 during operation and the leaked refrigerant is ignited.

The "predetermined rotation speed" can be, for example, the minimum rotation speed of the indoor fan. If the indoor fan 14 is operated at the minimum rotation speed or higher, even if the refrigerant leaks from the refrigeration cycle component, the leaked refrigerant can be sufficiently diffused, and the leaked refrigerant having a flammable concentration is contained in the refrigeration cycle component. It is possible to prevent contact with the high voltage portion of the discharge device arranged below. The minimum rotation speed of the indoor fan 14 varies depending on the model and the like, but is, for example, 300 rpm.

As the timing for starting the operation of the discharge device 8, for example, the control unit P of the indoor unit 1 monitors the rotation speed of the indoor fan 14 after the start of driving, and the predetermined time (first predetermined time) elapses. The operation of the discharge device 8 can be started when the rotation speed exceeds the predetermined rotation speed. Further, as the timing for stopping the operation of the discharge device 8, for example, the operation of the indoor fan 14 can be stopped after first stopping the operation of the discharge device 8. Further, for example, the rotation speed of the indoor fan 14 exceeds the predetermined rotation speed before a predetermined time (second predetermined time) elapses from the operation stop instruction of the indoor unit 1, that is, the indoor fan 14 by remote control operation. Sometimes the operation of the discharge device 8 can be stopped. In this case, since the indoor fan 14 is in a constant operating state during the operation of the discharge device 8, even if the refrigerant leaks from the refrigeration cycle component, the leaked refrigerant can be diffused by the air flow generated by the indoor fan 14. It is possible to prevent the leaking refrigerant having a flammable concentration from coming into contact with the high voltage portion of the discharge device 8 arranged below the refrigeration cycle component. In other words, even if the operation of the indoor fan 14 is stopped and the rotation speed of the indoor fan 14 becomes equal to or less than the predetermined rotation speed, the discharge device 8 is stopped at that time, so that the leaked refrigerant diffuses. Even if it comes into contact with the high voltage portion of the discharge device 8 without it, the leaked refrigerant does not ignite.

FIG. 3 shows the relationship between the on / off operation of the indoor unit 1, the rotation speed of the indoor fan 14, and the on / off of the discharge device 8 when the “predetermined rotation speed” is set to the minimum rotation speed of the indoor fan 14. It is a time flow. The horizontal axis shows time. Rotational speed of the indoor fan 14 in the first time of a predetermined time t1 has elapsed the start of the operation of the indoor fan 14 by turning on the operation of the indoor unit 1 reaches the minimum rotational speed f ₀ of the indoor fan 14 by remote control. Discharge device 8, the operation is started after the indoor fan 14 reaches the minimum rotational speed f _0.
On the other hand, lowering the rotation speed of the indoor fan 14 issues a shutdown instruction of the indoor fan 14 to turn off the indoor unit 1 to the second time the predetermined time t2 has elapsed by remotely controlled to the lowest rotational speed f ₀ of the indoor fan 14 do. Discharge device 8 stops the operation before the indoor fan 14 is reduced to minimum frequency f _0.

[Other variants]
The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.
For example, in the above-described embodiment, the ceiling-embedded indoor unit is illustrated, but as long as the discharge device is arranged below the refrigeration cycle component, other types of indoor units, such as a ceiling-suspended indoor unit, are used. The present invention can also be applied to a machine, a wall-mounted indoor unit, and the like.

FIG. 4 is a cross-sectional explanatory view of a ceiling-suspended indoor unit 21 according to another embodiment of the present invention. In the indoor unit 21, an air suction port 23 is formed on a part of the lower surface of the casing 22, is sucked into the machine from the suction port 23 by the indoor fan 24, and passes through the heat exchanger 25 to exchange heat. The conditioned air is blown into the living room space from the air outlet 26 formed on one side surface of the casing 22. A discharge device 27 is provided at the suction port 23. The discharge device 27 includes a frame body 28, an electrostatic filter 29, a discharge unit 30, a support frame 31 for supporting the discharge unit 30, and a pre-filter 32. Like the discharge device 8, the discharge device 27 includes a streamer. It causes an electric discharge to decompose harmful substances in the air. Further, a control unit P for controlling the operation of the indoor fan 24 and the discharge device 27 is arranged in the casing 22.

In the indoor unit 21 shown in FIG. 4, as in the indoor unit 1, the discharge device 27 is arranged below the refrigeration cycle component including the heat exchanger 25 and the refrigerant pipe, and the R32 refrigerant is from air. If the refrigerant leaks from the refrigeration cycle component, the leaked refrigerant may come into contact with the discharge section 30 in the discharge device 27. Even in this case, if the control unit P starts or stops the operation of the discharge device 27 in a state where the rotation speed of the indoor fan 24 exceeds a predetermined rotation speed, the refrigerant temporarily leaks from the refrigeration cycle component. Even if this is done, it is possible to avoid the risk that the leaked refrigerant having a flammable concentration will ignite due to contact with the high voltage portion of the discharging device 27 during operation.

Further, in the above-described embodiment, the discharge device that performs streamer discharge to generate an active species is exemplified, but the discharge device in the present invention is not limited to this, and has a general electrostatic dust collecting function. The present invention can also be applied to an indoor unit equipped with a discharge device having a discharge device.

Further, in the above-described embodiment, the control unit is arranged in the casing of the indoor unit, but such a control unit can be incorporated in, for example, a remote controller outside the indoor unit.

Further, in the above-described embodiment, the start or stop of the operation of the discharge device is controlled based on the rotation speed of the indoor fan, but the air flow capable of diffusing the leaked refrigerant after the operation of the indoor fan is started. If the time (first predetermined time) until the amount of air that can be generated is known in advance, the time (first predetermined time) has elapsed since the operation of the indoor fan was started. It can be controlled to start the operation of the discharge device later. The first predetermined time, that is, the time from the start of operation of the indoor fan to the start of operation of the discharge device can be, for example, 15 to 25 seconds.
If the time (second predetermined time) for maintaining the amount of air that can generate an air flow capable of diffusing the leaked refrigerant after the operation of the indoor fan is stopped is known in advance, the indoor fan is operated. The control may be such that the operation of the discharge device is stopped before the time (second predetermined time) elapses after the operation of the fan is stopped.

1: Indoor unit 2: Casing 3: Decorative panel 4: Suction port 5: Air outlet 5a: Flap 6: Suction grill 7: Pre-filter 8: Discharge device 9: Primary filter 10: Secondary filter 11: Opposite electrode 12: Ionization Wire 13: Streamer discharge electrode 13a: Electrode rod 13b: Needle electrode 14: Indoor fan 15: Heat exchanger 16: Motor 17: Impeller 18: Drain pan 21: Indoor unit 22: Casing 23: Suction port 24: Indoor fan 25: Heat exchanger 26: Suction port 27: Discharge device 28: Frame body 29: Electrostatic filter 30: Discharge unit 31: Support frame 32: Prefilter 50: Discharge device 51: Heat exchanger 52: Air conditioner 53: Air filter 54: Indoor fan 55: Gas sensor C: Ceiling P: Control unit

Claims (3)

The operation of the heat exchanger (15), the indoor fan (14), the discharge device (8) arranged below the heat exchanger (15), and the indoor fan (14) and the discharge device (8). An indoor unit (1) having a control unit (P) for controlling and using a slightly flammable or flammable refrigerant having a specific gravity larger than that of air.
Wherein the control unit (P) is the start of the operation of the discharge device (8), performs from the start of the operation of the prior SL indoor fan (14) after the elapse the first predetermined time, the discharge device (8 the stop of the operation of), have rows before the second predetermined time elapses after the operation stop instruction during operation or the indoor fan (14) of the indoor fan (14),
After the lapse of the first predetermined time, during the operation of the indoor fan (14) and before the lapse of the second predetermined time from the operation stop instruction of the indoor fan (14), the heat exchanger (15) The indoor unit (1) in which the leaked slightly flammable or flammable refrigerant is diffused to a concentration lower than the flammable concentration by an air flow generated by driving the indoor fan (14). The first predetermined time is a time when the rotation speed of the indoor fan (14) reaches a predetermined rotation speed.
The second predetermined time, the rotation speed of the indoor fan (14) is Ri time der to decrease the rotational speed during operation to said predetermined rotational speed,
When the indoor fan (14) is operating at the predetermined rotation speed, the slightly flammable or flammable refrigerant leaked from the heat exchanger (15) is diffused to a concentration less than the flammable concentration by the air flow. and that, the indoor unit according to claim 1 (1). Wherein the predetermined rotation speed, Ri minimum rotational speed der of the indoor fan (14),
When the indoor fan (14) is operating at the minimum rotation speed, the slightly flammable or flammable refrigerant leaked from the heat exchanger (15) is diffused to a concentration less than the flammable concentration by the air flow. are, the indoor unit according to claim 2 (1).

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