JP3211343B2 - Air cleaner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifier provided with a dust remover and a ventilator, and more particularly to an interlocking control between the dust remover and a ventilator.

[0002]

2. Description of the Related Art Two types of air purifiers having a dust removing device and a ventilation device are generally known.
That is, the dust control device and the ventilation device are individually controlled based on the indoor air quality standard.
As disclosed in Japanese Patent No. 1454, there is a device in which a dust removing device and a ventilation device are integrated, an air circulation fan is also used as a ventilation fan, and ventilation and air cleaning are performed only by switching dampers.

[0003]

In the above-described air purifier, the fan of the dust remover is driven at a low output (hereinafter referred to as an L notch) as long as the dust concentration does not exceed a reference value (0.15 mg / m ³ ). When the reference value is exceeded, the fan of the dust removing device is driven at a high output (hereinafter referred to as an H notch). Further, the concentration of carbon dioxide (CO ₂ ) is set to a reference value (100
In the range not exceeding 0 ppm), the fan of the ventilator is L-notched, and when it exceeds the reference value, the fan of the ventilator is H-notched. Therefore, in a state where the carbon dioxide concentration is equal to or lower than the reference value and the dust concentration is equal to or higher than the reference value, the fan of the dust removing device makes a H notch and the fan of the ventilation device makes an L notch so that the dust concentration becomes equal to or less than the reference value. Control.

[0004] However, in this state, the interior of the room may be further contaminated, and the dust concentration tends to increase even though the fan of the dust remover is H-notched. In such a case, the fan of the dust removing device has already reached the maximum capacity of H.
Since the motor is driven by the notch, it takes a considerable amount of time until the desired air quality, that is, the dust concentration becomes lower than the reference value. This not only impairs comfort for the user, but also leads to wasteful energy consumption.

Further, in the air purifier, when ventilation is performed, the damper is switched and one fan is used to suck indoor circulating air and outdoor air together. Ventilation while maintaining the air flow and control of air quality are not sufficient. Therefore,
As in the case of the air purifier described above, it takes a considerable amount of time to achieve the desired air quality, which not only impairs comfort for the user but also leads to wasteful energy consumption.

In view of the above, in the present invention, when the carbon dioxide gas concentration is equal to or less than the reference value and the dust concentration is equal to or more than the reference value, the ventilation air volume is increased to back up the dust and promote the cleaning. It is an object of the present invention to provide an air purifier capable of reducing dust removal time and realizing energy saving.

[0007]

Means for Solving the Problems According to the present invention, there is provided a dust removing apparatus for removing dust from indoor air and blowing clean air into the room through a dust removing fan, a heat exchanger, and a ventilation fan. inner adjacent the ventilator to perform heat exchange ventilation
In the installed air purifier, a dust sensor for detecting indoor dust concentration and a gas sensor for detecting indoor harmful gas concentration are provided in the indoor air circulation path, based on output signals from the dust sensor and the gas sensor. Air quality discriminating means for discriminating indoor air quality, and dust removal when the air quality discriminating means determines that the harmful gas concentration is below the reference value and the dust concentration is above the reference value during heat exchange ventilation. Cleaning promoting means for driving the fan and the ventilation fan with high output.

[0008]

In the above means for solving the above problems, at the time of heat exchange ventilation,
If the air quality determining means determines that the harmful gas concentration is below the reference value and the dust concentration is above the reference value, the cleaning promotion operation means drives the dust removal fan and the ventilation fan of the ventilation device to high output based on this. Let it.

[0009] Then, not only the air volume of the dust removal device but also the ventilation air volume of the ventilation device can be increased to back up the dust removal, so that the cleaning is promoted. Therefore, the indoor air quality can be returned to a normal state in a short time, and energy can be saved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. The internal configuration of the air purifier of the present embodiment will be described with reference to FIGS. FIG. 8 is a schematic diagram showing an attached state of the air purifier and an air flow at the time of heat exchange ventilation, and FIG. 9 is a schematic diagram showing an attached state of the air purifier and the air flow at the time of normal ventilation.

The air purifier of this embodiment is of the type embedded in the ceiling as shown in FIGS.
R2 is an outdoor, R3 is a ceiling, and 1 is an air purifier main body.
Inside the air purifier body 1, a dust remover C for removing dust in the air and a ventilator V for ventilating indoor air and outdoor air are provided adjacent to each other via an air filter 3.

The dust removing device C is disposed downstream of the air filter 3 and collects dust in the indoor circulating air RA1. The dust removing device C is circulated in a clean room where dust is removed by the dust collecting element 4. A dust removing fan MF2 for blowing the air SA1 into the room R1. The first supply duct 10 for supplying the clean room circulating air SA1 to the room R1 is connected to the dust removal device C. Further, between the dust collecting element 4 and the air filter 3, a dust sensor 12 for detecting a dust concentration in the indoor circulating air RA1 is arranged.

The ventilator V is disposed upstream of the air filter 3 for exchanging heat between the indoor ventilation air RA2 and the outdoor air OA, and the indoor heat exchange ventilation air EA passing through the heat exchanger 13 is supplied to the outdoor. Ventilation exhaust fan M exhausting to R2
F1 and the clean outside air SA that has passed through the high-performance filter 6.
2 to the room R1. The ventilator V is divided into four upper and lower chambers centered on the heat exchanger 13, and a first introduction port for introducing outdoor air OA into the ventilator V is shown on the upper left side in FIGS. The room 15 has an indoor ventilation air RA2 on the upper right side.
Into the heat exchanger 13, and a ventilation / exhaust fan MF <b> 1 at the lower left side is accommodated in the second introduction chamber 1.
7 has a first suction chamber 18 for sucking the indoor heat exchange ventilation air EA passing through the heat exchanger 13, and the outdoor air OA passing through the heat exchanger 13 from the first introduction chamber 15 on the lower right side. The second suction chambers 19 for sucking are provided. In addition, between the second introduction chamber 17 and the second suction chamber 19, a bypass path (not shown) for introducing outdoor air OA from the second introduction chamber 17 to the second suction chamber 19 bypassing the heat exchanger 13. Is connected.

An outside air temperature sensor 20 for detecting the temperature of the outdoor air OA shown in FIG. 5 is provided in the first introduction chamber 15, and a temperature of the room ventilation air RA2 shown in FIG. The inside air temperature sensors 21 to be detected are housed, respectively, and the boundary between the first introduction chamber 15 and the second introduction chamber 17 is set in accordance with the difference between the temperature of the outdoor air OA and the temperature of the indoor ventilation air RA2. A damper 22 for opening and closing the boundary is provided rotatably. The driving of the damper 22 is performed by a damper motor DM shown in FIG. And damper 2
In the case where the boundary between the first introduction chamber 15 and the second introduction chamber 17 is opened without rotating the second air passage 2, the outdoor air OA bypasses the heat exchanger 13 from the first introduction chamber 15 and passes through the bypass passage. 2
When the air is guided to the suction chamber 19 and ordinary ventilation is performed (see FIG. 9), on the other hand, when the damper 22 is rotated to close the boundary between the first introduction chamber 15 and the second introduction chamber 17, the first introduction chamber 15 is used. The outdoor air OA passes through the heat exchanger 13 and passes through the second suction chamber 19
And heat exchange ventilation (see FIG. 8). Note that the second introduction chamber 17 and the second suction chamber 19 are provided with the indoor circulating air RA1.
Is completely separated from the third introduction chamber 23 for guiding the air to the dust collecting element 4 so that no air flows.

The first introduction chamber 15 has outdoor air OA.
The first suction duct 24 for sucking air is provided in the second introduction chamber 1.
7, a second suction duct 25 for sucking the outdoor ventilation air RA2 is provided. In the first suction chamber 18, an exhaust duct 26 for discharging the indoor heat exchange ventilation air EA is provided in the third introduction chamber 23. The third suction duct 27 for sucking the room circulating air RA1 has a clean outside air SA in the second suction chamber 9.
Second supply ducts 11 for supplying 2 to the room R1 are connected to each other. At the end of the third suction duct 27 on the third introduction chamber 23 side, a carbon dioxide gas sensor 28 for detecting the concentration of carbon dioxide (CO ₂ ) in the indoor circulating air RA1 is arranged.

In the following description, the ventilation exhaust fan MF1 and the ventilation supply fan MF2 are collectively referred to as "ventilation fans MF1, MF2". Next, a control system of the air purifier will be described with reference to FIGS. FIG. 6 is a control diagram for heat exchange ventilation.
FIG. 7 is a control diagram during normal ventilation.

A control system for performing a normal ventilation operation includes:
As shown in FIG. 7, four zones X1 to X4 are divided by a reference value of the dust concentration and the CO ₂ concentration (a reference value of the dust concentration of 0.15 mg / m ³ and a reference value of the CO ₂ concentration of 1000 ppm). In any of the zones X4 to X4, the air volume of the ventilator V is set to High, and the interlocking control with the dust remover C is performed to save energy. That is, in the X1 zone where both the dust concentration and the CO ₂ concentration are equal to or less than the reference values, the dust removing fan MF2 is driven at a low output (hereinafter referred to as L notch) to operate the dust removing device C normally, and the ventilation fan MF1 , MF3 are driven to a high output (hereinafter referred to as H notch) to forcibly operate the ventilator V. In the X2 zone where the CO ₂ concentration is below the reference value and the dust concentration exceeds the reference value, the dust removal fan MF2 is notched at H, the dust removal device C is forcibly operated, and the ventilation fans MF1 and MF3 are set at H level.
Notch and forcibly operate ventilator V. In the X3 zone where the dust concentration is equal to or less than the reference value and the CO ₂ concentration exceeds the reference value, the dust removing fan MF2 is L-notched, the dust removing device C operates normally, and the ventilation fans MF1 and MF3 are H-notched. And the ventilation device V is forcedly operated. In the X4 zone where both the dust concentration and the CO ₂ concentration exceed the reference values, the dust removing fan MF2 is H-notched to forcibly operate the dust removing device C, and the ventilation fans MF1 and MF3 are notched for H notch. V is forcibly operated.

On the other hand, as shown in FIG. 6, the control system for performing the heat exchange ventilation operation includes four zones X1 to X4 with reference to the reference values of the dust concentration and the CO ₂ concentration as in the case of the normal ventilation. Then, the ventilation device V and the dust removal device C are linked and controlled in accordance with each zone of X1 to X4 to obtain an appropriate processing air volume. That is, in the X1 zone where both the dust concentration and the CO ₂ concentration are equal to or less than the reference values, the dust removing fan MF2 is notched L to operate the dust removing device C normally, and the ventilation fans MF1 and MF3 are notched L for ventilation. Minimize operation of the device V to save energy. In the X2 zone where the CO ₂ concentration is below the reference value and the dust concentration exceeds the reference value, the dust removal fan MF2 is H-notched to forcibly operate the dust removal device C, and the ventilation fans MF1 and MF3 are H-notched. Then, the ventilation device V is operated as a backup operation to promote the cleaning.
In the X3 zone where the dust concentration is equal to or less than the reference value and the CO ₂ concentration exceeds the reference value, the dust removal fan MF2 is L-notched, the dust removal device C operates normally, and the ventilation fan M
F1 and MF3 are H-notched to forcibly operate the ventilator V to promote ventilation. In the X4 zone where both the dust concentration and the CO ₂ concentration exceed the reference values, the dust removing fan MF2
Is H-notched to forcibly operate the dust removal device C, and the ventilation fans MF1 and MF3 are H-notched to forcibly operate the ventilation device V to forcibly clean the ventilation.

The means for realizing the above control system will be described with reference to FIGS. 1 is a functional block diagram of the control system during heat exchange ventilation of the air purifier, and FIG. 2 is a functional block diagram of the control system during normal ventilation. The air purifier includes, as shown in FIGS. 1 and 2, a dust concentration determining unit 30 that determines whether the dust concentration exceeds a reference value based on an output signal of the dust sensor 12 and an output signal of a carbon dioxide gas sensor 28. , CO ₂ concentration determining means 31 for determining whether the CO ₂ concentration exceeds the reference value
And a ventilation operation determining means 32 for determining whether the current operation mode is a normal ventilation operation or a heat exchange ventilation operation.
When the ventilation operation determination means 32 determines that the current operation mode is the normal ventilation operation, the ventilation fans MF1,
Ventilation device forced operation means 33 forcibly operating the ventilation device V by forcing the MF3 to H notch, and forcibly setting the ventilation fans MF1 and MF3 to H notch by the ventilation device forced operation means 33, and then determining the dust concentration. 30, when it is determined that the dust concentration does not exceed the reference value, the dust removal fan MF
2 is L-notched, the dust removing device C operates normally, and when it is determined that the dust concentration exceeds the reference value, the dust removing fan MF2 is H-notched and the dust removing device operation control means 34 forcibly operates the dust removing device C. are doing.

When it is determined by the ventilation operation determining means 32 that the current operation mode is the heat exchange ventilation operation, the indoor air level is determined based on the determination signals from the dust concentration determining means 30 and the carbon dioxide concentration determining means 31. Air quality determining means 35 for determining which zone of the above X1 to X4 the quality corresponds to;
When it is determined by the air quality determining means 35 that the air quality corresponds to the X1 zone, the dust removing fan MF2 is L-notched, the dust removing device C operates normally, and the ventilation fans MF1, M
When the air quality is determined to correspond to the X2 zone by the energy saving operation means 36 for performing the minimum operation of the ventilation device V by making the F3 notch L and the air quality determination means 35, the dust removal fan MF2 is H-notched to force the dust removal device C. The ventilation fan MF1, MF3 is L-notched, and the ventilation device V is minimally operated. If the dust concentration tends to increase after a certain period of time, the ventilation fan MF1, MF3 is H-notched, and the ventilation device V is backed up. Cleaning promotion driving means 37
When the air quality determining means 35 determines that the air quality corresponds to the X3 zone, the dust removing fan MF2 is notched L, the dust removing device C operates normally, and the ventilation fan MF
When the air quality is determined to be equivalent to the X4 zone by the ventilation promotion operation means 38 for forcibly operating the ventilation device V by notching the MF3 and H, the dust removal fan MF2 and the ventilation fans MF1, MF3 Are forced to H-notch, forcibly operating the dust removal device C and the ventilation device V.

The electrical configuration of the control system will be described with reference to FIG. FIG. 5 is a block diagram showing an electrical configuration of the control system. In FIG. 5, reference numeral 50 denotes a function of detecting the CO ₂ concentration of the indoor air based on the output signal of the carbon dioxide gas sensor 28, and a temperature difference between the indoor air and the outdoor air based on the output signals of the outside air temperature sensor 20 and the inside air temperature sensor 21. The control circuit 51 has a function of detecting the dust concentration and a function of outputting control signals to the damper 22 and the ventilation fans MF1 and MF3 of the ventilation device V. The detection circuit 51 detects the dust concentration of the indoor air based on the output signal of the dust sensor 12. The control circuit 52 has a function of determining the air quality of the indoor air based on the CO ₂ concentration information and the ventilation operation determination information from the control circuit 50 and the dust concentration information from the control circuit 51, and a dust removal fan MF2. And a control circuit for outputting a control signal to the ventilation air supply fan MF3.

Reference numerals 53 and 54 denote communication circuits for exchanging information of the control circuits 50 and 52, and reference numerals 55 and 56 denote control circuits 51 and 52.
This is a communication circuit for exchanging information. 57 is a control circuit 5
The drive circuit 58 drives the damper motor DM that rotates the damper 22 and the ventilation exhaust fan MF1 based on the control signal of 0,
This is a drive circuit for driving the dust removal fan MF2 and the ventilation supply fan MF3.

Reference numeral 59 denotes a remote control switch 60
And a communication circuit 61 for outputting the air purification information from the control circuit 50 to the air conditioner. Reference numeral 62 denotes a high voltage power supply for supplying a high voltage to the dust collecting element 4. Then, the control circuit 50, the communication circuits 53 and 61, the drive circuit 57, and the receiving circuit 59 include the control circuit 5 in the first electrical box 63.
1. The communication circuit 56 and the high voltage power supply 62 are connected to the second electrical box 64 by the control circuit 52 and the communication circuits 54 and 56,
It is built in the third electrical component box 65, respectively.

Here, the remote control switch 6
0, each fan MF of the dust remover C and the ventilator V when the circulating air volume, ventilation volume and ventilation switching are set to automatic
Table 1 shows the air flow rates of MF1, MF2 and MF3.

[0025]

[Table 1]

The operation of the air purifier will be described with reference to the flowcharts of FIGS. FIG. 3 is a control flowchart of the air purifier, and FIG. 4 is a control flowchart at the time of heat exchange ventilation. In FIG. 3, when the air purifier is started by the remote control switch 60 and the automatic ventilation operation signal is output from the remote control switch 60, the automatic ventilation operation is started in Step 1, and the automatic ventilation operation is started in Step 2.
Then, the ventilation operation determining means 32 determines whether the current ventilation operation is a normal ventilation operation or a heat exchange ventilation operation.

If it is determined in Step 2 that the normal ventilation operation is being performed (see FIG. 9), the process proceeds to Step 3 where the forced ventilation device 33 operates the ventilation fans MF1, MF.
3 is H-notched, and then in Step 4 the dust concentration determination means 3
0 is based on the output signal from the dust sensor 12 and determines whether or not the dust concentration exceeds a reference value (0.15 mg / m ³ ). If it is determined in Step 4 that the dust concentration is equal to or lower than the reference value, the process proceeds to Step 5, and the dust removing device MF2 is notched by the dust removing device operation control means 34 in the L notch. on the other hand,
If it is determined in Step 4 that the dust concentration exceeds the reference value, the process proceeds to Step 6, and the dust removal device operation control means 3
At step 4, the dust removal fan MF2 is H-notched. in this way,
At the time of the normal ventilation operation, the indoor air quality is X1 shown in FIG.
Regardless of the zone of X4, the ventilation device V is forcibly operated to increase the ventilation air volume, and the dust removal air volume of the dust removal device C is controlled based on whether or not the dust concentration exceeds the reference value, so that energy saving can be achieved. .

On the other hand, in Step 2, the heat exchange ventilation operation (FIG. 8)
Is determined, the process proceeds to Step 7, where the control step of the heat exchange ventilation operation shown in FIG. 4 is started. In the control step of the heat exchange ventilation operation, Ste
At step p8, the carbon dioxide concentration determining means 31
It is determined whether or not the concentration of carbon dioxide (CO ₂ ) exceeds the reference value (1000 ppm) based on the output signal from.
If it is determined in Step 8 that the carbon dioxide gas concentration is equal to or less than the reference value, in Step 9 the dust concentration determination unit 30 determines whether the dust concentration exceeds the reference value. If it is determined in Step 9 that the dust concentration is equal to or less than the reference value, Step
The flow then proceeds to p10, where the air quality determination means 35 determines that the indoor air quality is in the X1 zone shown in FIG. 6, and based on this, the energy saving operation means 36 sets the ventilation fan MF.
1, the MF3 is L-notched, and the dust removal fan MF2 is L-notched. As described above, when the carbon dioxide concentration and the dust concentration are equal to or lower than the reference values, the processing air volumes of the ventilation device V and the dust removal device C are both set to the minimum air volume. Since the load on the conditioner can be reduced, energy can be saved.

On the other hand, if it is determined in Step 9 that the dust concentration exceeds the reference value, the process proceeds to Step 11, and the air quality in the room is determined by the air quality determining means 35 as X2 shown in FIG.
It is determined that the zone is a zone, and based on this, the cleaning promotion operation means 37 first makes the ventilation fan MF1, MF3 an L notch, and makes the dust removal fan MF2 an H notch, and after a certain period of time, the dust concentration tends to increase in Step12. It is determined whether or not there is. If it is determined in Step 12 that the dust concentration is further increasing, the flow shifts to Step 13, where the cleaning promotion operating means 37 further makes the ventilation fans MF1 and MF3 H-notch. On the other hand, if it is determined in Step 12 that the dust concentration has become equal to or less than the reference value, the process proceeds to Step 14, and the ventilation fans MF1 and MF3 are L-notched. in this way,
If the carbon dioxide concentration is lower than the reference value and the dust concentration is higher than the reference value, the dust removal air volume of the dust removal device C is increased. If the dust concentration is still increasing, the ventilation air volume of the ventilation device V is increased to remove the dust. Backup is promoted. Therefore, the indoor air quality can be returned to a normal state in a short time, and energy can be saved.

When it is determined in Step 8 that the carbon dioxide gas concentration exceeds the reference value, the dust concentration determination means 30 determines in Step 15 whether the dust concentration exceeds the reference value. If it is determined in Step 15 that the dust concentration is equal to or less than the reference value, the process proceeds to Step 16, where the air quality determining unit 35 determines that the indoor air quality is the X3 zone shown in FIG. Ventilation promotion operation means 3
8 makes the ventilation fans MF1 and MF3 H-notch and the dust removal fan MF2 L-notch. As described above, when the carbon dioxide gas concentration is equal to or higher than the reference value and the dust concentration is equal to or lower than the reference value, the ventilation air volume of the ventilator V is increased, so that ventilation is promoted.

On the other hand, if it is determined in Step 15 that the dust concentration exceeds the reference value, the flow shifts to Step 17, and
The air quality in the room is determined by the air quality determination means 35 as shown in FIG.
It is determined that there are four zones, and based on this, the forced ventilation / cleaning operation means 39 performs H notch on both the ventilation fans MF1, MF3 and the dust removal fan MF2. As described above, when the carbon dioxide gas concentration and the dust concentration are both equal to or higher than the reference values, the processing air volumes of the dust removing device C and the ventilation device V are increased, so that the ventilation cleaning is forcibly performed.

Therefore, as described above, by performing the interlocking control of the dust removing device C and the ventilating device V, appropriate control can be performed for each zone of the air quality, thereby improving comfort and saving energy. can do. It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made within the scope of the present invention.

For example, in the above-described embodiment, an example in which a carbon dioxide gas sensor is used as the gas sensor has been described. However, a sensor capable of detecting a harmful gas such as an oxygen or nitrogen gas sensor may be used.

[0034]

As is apparent from the above description, according to the present invention, when the harmful gas concentration in the room is lower than the reference value and the dust concentration in the room is higher than the reference value during heat exchange ventilation, the dust removing device is used. In addition to the dust removal air volume, the ventilation air volume of the ventilation device can be increased to back up the dust removal and promote the cleaning.

Therefore, it is possible to return the indoor air quality to a normal state in a short time, and there is an excellent effect that the energy can be saved.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a control system at the time of heat exchange ventilation of an air purifier according to one embodiment of the present invention.

FIG. 2 is a functional block diagram of the control system during normal ventilation.

FIG. 3 is a control flowchart of the air purifier.

FIG. 4 is a control flowchart at the time of heat exchange ventilation.

FIG. 5 is a block diagram illustrating an electrical configuration of a control system.

FIG. 6 is a control diagram in heat exchange ventilation.

FIG. 7 is a control diagram during normal ventilation.

FIG. 8 is a schematic diagram showing an attached state of an air purifier and an air flow at the time of heat exchange ventilation.

FIG. 9 is a schematic diagram showing an attached state of the air purifier and an air flow during normal ventilation.

[Explanation of symbols]

 C Dust removal device MF2 Dust removal fan V Ventilation device MF1, MF3 Ventilation fan 12 Dust sensor 13 Heat exchanger 28 Carbon dioxide sensor 35 Air quality discriminating means 37 Purification promoting means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 46/00-46/54 B01D 53/30 F24F 7/007 F24F 7/08 101

Claims (1)

(57) [Claims] 1. A dust removing device (C) for removing dust from indoor air and blowing clean air into a room through a dust removing fan (MF2).
When the heat exchanger (13), ventilation fan (MF1) (MF3) ventilator that performs heat exchange ventilator has a (V) and the air is decorated adjacent Kiyoshi
In a purifier, a dust sensor (12) that detects the concentration of dust in the room and a gas sensor that detects the concentration of harmful gas in the room in the indoor air circulation path
Air quality determining means (35) for determining indoor air quality based on output signals from the dust sensor (12) and the gas sensor (28).
When the air quality determination means (35) determines that the harmful gas concentration is below the reference value and the dust concentration is above the reference value during heat exchange ventilation, the dust removal fan (MF2) and the ventilation fan (MF
1) An air purifier comprising: a cleaning promotion operation means (37) for driving the (MF3) at a high output.