Ventilation system and method

Abstract

To provide a ventilation system, etc. capable of reducing energy loss and constructing a comfortable environment by controlling a circulation operation and an air exhaust operation in accordance with indoor air quality in a timely manner.SOLUTION: A ventilation system 100 includes: a function for performing an air exhaust operation for discharging sucked air to an outdoor side; a function for performing a circulation operation for returning the sucked air to an indoor side through a circulation filter; an air quality sensor 20 for detecting air quality of indoor air to be sucked; and a control section 172 that controls the circulation operation and the air exhaust operation on the basis of the air quality information detected by the air quality sensor. The control section refers to at least two pieces of air quality information and controls the circulation operation and the air exhaust operation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a ventilation system and method.

Background Art

[0002] When performing ventilation with a large air volume by a ventilation device such as a range hood, air different from the indoor air quality is brought in from the air supply openings and gaps of the house, which may impair the comfort of the indoor environment such as an increase or decrease in room temperature. On the other hand, when oil fumes are generated by cooking or the indoor air quality deteriorates, it is necessary to exhaust with a large air volume and take in outdoor air to improve the indoor environment. Therefore, conventionally, there has also been proposed a range hood that has an exhaust function of exhausting with a large air volume and has a circulation function of returning the inhaled air indoors through a circulation filter that removes / reduces a predetermined gas component so as not to bring in air from the outside.

[0003] For example, Patent Document 1 discloses a range hood system that can prevent forgetting to start or stop an exhaust fan and can effectively detect or discharge various gases. This range hood system includes a range hood body that partitions an exhaust path, a main fan and a sub-fan that exhaust through the exhaust path, a gas sensor disposed near the range hood body, and a control unit that controls at least the main fan and the sub-fan based on the output from this gas sensor, and switches between exhaust / circulation according to the output of the gas sensor. And in this range hood system, when performing circulation operation, the gas sensor detects the odor level after a predetermined time has elapsed since the start of the circulation operation, and switches to the exhaust operation when the odor level does not decrease, but continues the circulation operation until a predetermined time has elapsed when the odor level remains low.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the above-described conventional technology operates either in a circulation operation or an exhaust operation, the circulation operation continues until a predetermined time has elapsed. The timing of switching from the circulation operation to the exhaust operation is fixed and cannot be switched in a timely manner, resulting in the circulation operation continuing unnecessarily and leading to energy loss.

[0006] Therefore, the present invention has been devised in view of such circumstances, and provides a ventilation system and method for reducing energy loss and constructing a comfortable environment by controlling the circulation operation and the exhaust operation in a timely manner according to the indoor air quality.

Means for Solving the Problems

[0007] In order to solve the above problems, there is provided a ventilation system including a function of performing an exhaust operation for exhausting the inhaled air outdoors, a function of performing a circulation operation for returning the inhaled air indoors through a circulation filter, an air quality sensor for detecting the air quality of the indoor air to be inhaled, and a control unit for controlling the circulation operation and the exhaust operation based on the air quality information detected by the air quality sensor. The control unit controls the circulation operation and the exhaust operation by referring to at least two pieces of air quality information. According to this, by controlling the circulation operation and the exhaust operation based on at least two air qualities, it is possible to provide a ventilation system that controls the circulation operation and the exhaust operation in a timely manner according to the indoor air quality, reduces energy loss, and constructs a comfortable environment.

[0008] Furthermore, the air quality sensor may be a first air quality sensor for detecting the air quality of the air before passing through the circulation filter, and may further include a second air quality sensor for detecting the air quality of the air after passing through the circulation filter. The control unit may be characterized in that it controls the circulation operation and the exhaust operation based on a comparison of the air quality information detected by the first air quality sensor and the second air quality sensor. According to this, by controlling the circulation operation and the exhaust operation based on the comparison of the air quality information before and after passing through the circulation filter, it is possible to make a more accurate and timely determination.

[0009] Furthermore, the control unit compares a first difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a first time point, and a second difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a second time point after the first time point, and when the second difference is approximately equal to or larger than the first difference, controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. According to this, by comparing the differences in the air quality information detected at two time points respectively, and when the differences remain approximately equal or expand, controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, the state of the indoor air quality (such as the state of generation of pollutants, the collection state by the circulation filter, etc.) can be determined more accurately and timely.

[0010] Furthermore, the control unit compares a first difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a first time point, and a second difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a second time point after the first time point, and when the second difference is larger than the first difference, controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. According to this, by comparing the differences in the air quality information detected at two time points respectively, and when the differences are expanding, controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, the state of the indoor air quality can be determined more accurately and timely.

[0011] Furthermore, the control unit compares a first difference between two air quality information items detected by the first air quality sensor and the second air quality sensor at a first time point, and a second difference between two air quality information items detected by the first air quality sensor and the second air quality sensor at a second time point after the first time point, and controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation when the second difference is substantially equal to the first difference and both differences are greater than a predetermined difference. According to this, by comparing the differences in the air quality information detected at two time points, and when the differences remain substantially equal and both differences are greater than a predetermined difference, controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, the state of the indoor air quality can be determined more accurately and in a timely manner.

[0012] Furthermore, the control unit may be characterized by controlling the circulation operation and the exhaust operation based on the amount of change over time of the air quality information detected by the air quality sensor. According to this, by controlling the circulation operation and the exhaust operation based on the amount of change over time of the air quality information detected at at least two time points, it is possible to make a more accurate and timely determination.

[0013] Furthermore, when the control unit determines that the air quality information at the second time point among the time series data of the air quality information detected by the air quality sensor has an improving trend compared to the air quality information at the first time point before the second time point, and it is not expected that the predetermined air quality can be achieved within a predetermined time even if the improving trend continues, the control unit may be characterized by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. According to this, when the time series change of the air quality information has an improving trend but it is not expected that the predetermined air quality can be achieved within a predetermined time even if the improving trend continues, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, it is possible to achieve a comfortable air quality environment at an early stage.

[0014] Furthermore, when the control unit determines that the air quality is improving based on the air quality information detected by the air quality sensor at least at two time points, and when the improvement trend satisfies a predetermined condition, the control unit starts referring to the air quality information at a time interval shorter than the time interval it referred to before satisfying the predetermined condition. If it is not expected that the predetermined air quality can be achieved within a predetermined time even if the improvement trend of the air quality detected at least at two time points at the short time interval continues, the control unit may control to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. According to this, even though the time-series change of the air quality information shows an improving trend, if it is not expected that the predetermined air quality can be achieved within a predetermined time even if the improvement trend when detected at a shorter and more detailed time interval continues, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, it is possible to achieve a comfortable air quality environment earlier.

[0015] Furthermore, when the control unit determines that the air quality is deteriorating based on the air quality information detected by the air quality sensor at least at two time points, and when the deterioration rate of the deterioration trend is greater than a predetermined rate, the control unit may control to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. According to this, when the air quality information detected by the air quality sensor at two time points shows a deterioration trend greater than a predetermined rate, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, the circulation operation and the exhaust operation can be controlled in a timely manner according to the indoor air quality.

[0016] Furthermore, the air quality sensor includes a fourth air quality sensor that detects the air quality installed near the ventilation device and a third air quality sensor installed at a position farther from the fourth air quality sensor. The control unit may control the circulation operation and the exhaust operation based on the time difference between the time when the third air quality sensor detects the air quality information of a predetermined threshold value and the time when the fourth air quality sensor detects the air quality information of a predetermined threshold value. According to this, by controlling the circulation operation and the exhaust operation based on the time difference between detecting air quality information of a predetermined threshold value at a distant position and detecting air quality information of a predetermined threshold value in the vicinity, a comfortable environment can be constructed indoors.

[0017] Furthermore, the fourth air quality sensor is located on the flow path from the third air quality sensor to the ventilation device, and when the control unit determines that the air quality information detected by the third air quality sensor has a deteriorating tendency when it is equal to or higher than a predetermined threshold value, and within a predetermined time after detecting that the air quality information detected by the third air quality sensor is the predetermined threshold value, when the fourth air quality sensor detects air quality information equal to or higher than the predetermined threshold value, it may be characterized in that the control unit controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. According to this, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation when an air quality sensor located upstream on the flow path of the air flow detects that the air quality information is the predetermined threshold value and a downstream air quality sensor detects the same level of air quality information within a predetermined time, a comfortable environment can be constructed indoors.

[0018] Furthermore, it may further include an outdoor air quality information acquisition means for acquiring outdoor air quality information, and the control unit may be characterized in that it controls the circulation operation and the exhaust operation based on a comparison between the air quality information acquired by the outdoor air quality information acquisition means and the air quality information detected by the air quality sensor. According to this, by controlling the circulation operation and the exhaust operation based on a comparison between the outdoor and indoor air quality information, the air quality of the indoor air can be improved by utilizing the air quality of the outdoor air.

[0019] In order to solve the above problems, in a ventilation system comprising a function of performing an exhaust operation of exhausting the inhaled air outdoors, a function of performing a circulation operation of returning the inhaled air indoors through a circulation filter, and an air quality sensor for detecting the air quality of the indoor air being inhaled, a method for controlling the circulation operation and the exhaust operation based on the air quality information detected by the air quality sensor is provided, and a method for controlling the circulation operation and the exhaust operation by referring to at least two pieces of air quality information detected by the air quality sensor is provided. According to this, by controlling the circulation operation and the exhaust operation based on at least two pieces of air quality information, it is possible to provide a method for a ventilation system that controls the circulation operation and the exhaust operation in a timely manner according to the indoor air quality, reduces energy loss, and constructs a comfortable environment.

Effects of the Invention

[0020] As described above, according to the present invention, it is possible to provide a ventilation system and method that reduce energy loss and construct a comfortable environment by controlling the circulation operation and the exhaust operation in a timely manner according to the indoor air quality.

Brief Description of the Drawings

[0021]

Figure 1

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Figure 12

Mode for Carrying Out the Invention

[0022] Hereinafter, each embodiment according to the present invention will be described with reference to the drawings. <First Embodiment> Referring to FIGS. 1 to 12, the ventilation system 100 in this embodiment will be described. The ventilation system 100 is installed indoors in a building such as a house or a store, and functions to exchange indoor and outdoor air or circulate indoor air in order to bring the indoor air quality closer to a desirable air quality. In this embodiment, as a representative example of the ventilation device, the range hood 10 installed in the kitchen of a house will be used for description. Of course, it is not limited to this. For example, it may be a commercial fryer hood installed in the kitchen of a store or a dust ventilation device installed in a factory.

[0023] Note that the air quality in this specification refers to substances constituting air (such as oxygen, carbon monoxide, carbon dioxide, etc.), substances contained in air (such as moisture, oil, dust, particulate matter, volatile organic compounds (VOCs), odor substances, etc. in particulate or gaseous form), an index indicating the kinetic energy of air (temperature), etc., and is a concept indicating the quality of air that can be felt or affected by humans. Air quality is generally measured using sensors corresponding to each air quality, such as temperature, humidity, carbon monoxide concentration, pollutant concentration, etc.

[0024] The ventilation system 100 includes a range hood 10, a plurality of sensor units 20 capable of communicating with the range hood 10, an operation switch 30 for operating the range hood 10, a smartphone 40 and a cloud server 50 capable of communicating with the range hood 10. The range hood 10 is provided above the stove installed in the kitchen, etc., sucks air containing fumes generated during cooking on the stove, performs an exhaust operation of discharging the air to the outside after removing the fumes with an oil collection filter 12, or performs a circulation operation of returning the air to the inside through a circulation filter such as a deodorizing filter 15 after removing the fumes with the oil collection filter 12.

[0025] When the ventilation system 100 operates in a circulation mode, the indoor area does not become negatively pressurized, so the air in the house rarely enters the room through the air intake or the like. Not only is it easy to keep the indoor air quality constant, but also the concentration of odor substances contained in the indoor air gradually decreases by passing through a circulation filter such as the deodorizing filter 15. On the other hand, when the concentration of odor substances suddenly increases, it takes a long time to deodorize through the circulation filter, and depending on the type of pollutant, the air quality may not improve even if a lot of time is spent. For example, in this embodiment, the circulation filter is the deodorizing filter 15, but the deodorizing filter 15 cannot reduce the concentration of CO2.

[0026] On the other hand, when the ventilation system 100 operates in an exhaust mode, since it sucks in a large air volume, it can collect oil fumes generated on the stove during cooking and prevent the oil fumes from diffusing indoors. Or, since it sucks in with a high static pressure, it can perform so-called ventilation to replace the indoor air with outdoor air in a short time regardless of the type of air quality by introducing air different from the indoor air quality from the air intake of the house or the like. On the other hand, the intrusion of outdoor air into the room may deteriorate the indoor air quality and impair the comfort of the indoor environment (for example, when exhaust operation is performed during cooling in summer, the indoor temperature rises). Thus, by accurately combining and controlling the exhaust operation and the circulation operation based on the indoor and outdoor air qualities, it becomes possible to improve and maintain the indoor air quality in a good state while avoiding continuous wasteful operation. The ventilation system 100 is what realizes this.

[0027] As shown in FIGS. 1 and 2, the range hood 10 includes a fan 11 that generates an air flow from the hood portion 19 to the exhaust port 182 or the circulation air outlet 181, an oil collection filter 12 disposed upstream of the air flow of the fan 11, an electrostatic precipitator 14 disposed in the flow path between the oil collection filter 12 and the fan 11, an exhaust / circulation switching damper 13 disposed downstream of the air flow of the fan 11 and switching the flow path so that air flows to the exhaust port 182 during exhaust operation and to the circulation air outlet 181 during circulation operation, a deodorizing filter 15 disposed upstream of the air flow of the circulation air outlet 181 and removing odor substances before returning the sucked air to the room, an input / output interface 16 that receives an operation signal from the operation switch 30, a communication unit 171 that communicates with one or more sensor units 20 and receives sensor values from each sensor unit 20, and a control unit 172 that acquires air quality information which is the sensor value received by the communication unit 171 and controls exhaust operation and circulation operation.

[0028] The fan 11 is preferably a sirocco fan that can suck with high static pressure, but is not particularly limited, and may be, for example, an axial flow fan. The oil collection filter 12 is, in this embodiment, an Oil Smasher (registered trademark) that rotates a disk-shaped filter with holes to collect oil, but is not limited thereto, and may be, for example, a HEPA filter. The electrostatic precipitator 14 is an arbitrary device that applies a high voltage to fine particles in the air flowing through the flow path to charge them and attracts them to the dust collection electrode for collection.

[0029] The exhaust / circulation switching damper 13 is composed of two dampers (Fig. 2(C)). When performing the exhaust operation, the damper on the left side in the figure is opened and the damper on the right side in the figure is closed. When performing the circulation operation, the control unit 172 drives and controls a motor (not shown in the figure) so that the damper on the left side in the figure is closed and the damper on the right side in the figure is opened. When performing the exhaust operation, since the damper on the left side in the figure is opened and the damper on the right side in the figure is closed, the air sucked by the fan 11 forms a flow path flowing toward the exhaust port 182 connected to the outdoor exhaust duct. Conversely, when performing the circulation operation, since the damper on the left side in the figure is closed and the damper on the right side in the figure is opened, the air sucked by the fan 11 forms a flow path flowing toward the circulation air outlet 181. The function of performing the exhaust operation of the range hood 10 is to form a flow path for the air sucked by the fan 11 to flow toward the exhaust port 182, and the function of performing the circulation operation of the range hood 10 is to form a flow path for the air sucked by the fan 11 to flow toward the circulation air outlet 181. The functions of performing the exhaust operation and the circulation operation will be described later.

[0030] The input / output interface 16 receives an operation signal from the operation switch 30 and transmits it to the control unit 172. The control unit 172 controls the range hood 10 according to the operation signal. The operation switch 30 is composed of a normal operation switch (such as air volume settings like weak, medium, and strong), a constant ventilation operation switch, and a hybrid operation switch. Each switch generates an operation signal indicating the operation. Note that the hybrid operation will be described later. The communication unit 171 is arranged indoors and has a communication function of communicating with one or more sensor units 20 at a relatively short distance and receiving data. Also, the communication unit 171 may have a communication function of connecting to the Internet and transmitting and receiving data with the cloud server 50. These communication functions are not particularly limited and are appropriately executed by known communication technologies.

[0031] The control unit 172 is composed of a microprocessor that performs various arithmetic operations, and includes a memory for storing control programs such as an OS (Operating System) and programs that define various processing procedures. Further, the memory may be configured to store the sensor values from the sensor unit 20 received by the communication unit 171. The control unit 172 may transmit the sensor values, driving status, etc. from each sensor unit 20 to the cloud server 50 via the communication unit 171 and accumulate these data. Note that the user of the ventilation system 100 can refer to the driving status, data history, etc. by accessing these data on the cloud server 50 using the smartphone 40.

[0032] The sensor unit 20 includes, inside, sensors for detecting various air qualities and a communication unit for communicating with the communication unit 171 of the range hood 10. In this embodiment, an example including a first sensor unit 21, a second sensor unit 22, and a third sensor unit 23 is shown. The first sensor unit 21 has, inside, a thermosensor, a temperature and humidity sensor, a VOC sensor, a dust sensor, and a CO2 sensor, and the second sensor unit 22 and the third sensor unit 23 have a temperature and humidity sensor, a VOC sensor, a dust sensor, and a CO2 sensor.

[0033] The thermosensor detects the temperature of a stove or a pot placed on the stove. The temperature and humidity sensor detects the temperature and humidity of the air at the location where the sensor unit 20 is disposed. The VOC sensor is a sensor that detects various organic compounds and some inorganic compounds in the air. The dust sensor is a sensor that detects the concentration of fine particles floating in the air. The CO2 sensor is a sensor that detects the concentration of carbon dioxide in the air. Note that the sensors for detecting air quality included in each sensor unit 20 are not limited to these, and for example, a carbon monoxide concentration sensor may be included. Further, these sensors detect by known methods for detecting respective air qualities.

[0034] The first sensor unit 21 has a thermosensor disposed on the lower surface of the range hood 10 and other sensors disposed on the front surface, and detects the air quality of the air in a cooking space such as a kitchen where the range hood 10 is installed. The second sensor unit 22 is installed at a position farther from the range hood 10 than the first sensor unit 21, such as in a living room which is a non-cooking space. In other words, the first sensor unit 21 is located on the air flow path of the air flowing from the second sensor unit 22 to the range hood 10. The third sensor unit 23 is installed at an air supply port or the like which is a location separating the indoor and outdoor areas, and when supplying outdoor air indoors by the built-in air supply fan, each sensor detects the air quality of the outdoor air. Therefore, the first sensor unit 21 and the second sensor unit 22 are a group of sensors for detecting the indoor air quality. On the other hand, the third sensor unit 23 is a group of sensors for detecting the outdoor air quality, and is an example of a means for acquiring outdoor air quality information. This means for acquiring outdoor air quality information is not limited to this, and for example, it may be configured to access information on the Internet via the communication unit 171 and acquire air quality information (particularly temperature and humidity information) in the vicinity of the house where the range hood 10 is installed.

[0035] Note that by installing two sensor units 20, namely the first sensor unit 21 disposed on or near the range hood 10 and the second sensor unit 22 disposed in a living room or the like farther from the range hood 10 than the first sensor unit 21, inside the house, it is possible to detect changes in air quality accompanying the movement of air. When the range hood 10 is operated for exhaust, the air existing in the kitchen is sucked, then the air in the living room or the like is sucked, and outdoor air is introduced from an air supply port or the like in the living room or the like, and gradually replaced with outdoor air.

[0036] That is, immediately after starting the exhaust operation, the first sensor unit 21 detects the air quality of the air in the kitchen, and the second sensor unit 22 detects the air quality of the air in a remote location such as the living room. However, after the exhaust operation has been carried out for a while, the first sensor unit 21 detects the air quality of the air in the living room and the like, and the second sensor unit 22 detects the air quality of the outdoor air. Therefore, the first sensor unit 21 can detect the air quality detected by the second sensor unit 22 with a time difference according to the speed of the air flow indoors and the distance to the second sensor unit 22. The first sensor unit 21 and the second sensor unit 22 are preferably arranged within a range where there is a certain spatial connection. However, as long as they are within the air flow path sucked by the exhaust operation of the range hood 10, the distance is not limited. For example, when the air supply port is in a bedroom farther from the living room, the second sensor unit 22 may be in the bedroom. Also, in this embodiment, the number of sensor units 20 for detecting the indoor air quality is two, but it is not limited to this, and three or more may be used.

[0037] Referring to FIGS. 3 to 5, the functions of performing the exhaust operation and the circulation operation will be described. As described above, the user of the ventilation system 100 can perform normal operation, constant ventilation operation, and hybrid operation using the operation switch 30. In the normal operation, the ventilation system 100 mainly rotates the fan 11 at a weak, medium, or strong air volume specified by the operation switch 30 when cooking to perform the exhaust operation. In the constant ventilation operation, the ventilation system 100 rotates the fan 11 at a very small air volume until an instruction to stop is given to perform the exhaust operation. In the hybrid operation, the ventilation system 100 shifts the mode based on the air quality detected by the sensor unit 20, rotates the fan 11 at an air volume suitable for the mode, opens and closes the exhaust / circulation switching damper 13, and performs the exhaust operation or the circulation operation.

[0038] In hybrid operation, there are normal operation and four operation modes: cooking temperature mode / CO2 mode / VOC·dust mode / temperature and humidity mode. Initially, normal operation is performed. In normal operation, the fan 11 is rotated at a low air volume to perform circulation operation. The ventilation system 100 (control unit 172) acquires and refers to the sensor values detected by the sensor unit 20 during the normal operation, and shifts the mode according to the sensor values. More specifically, when the sensor values referred to during normal operation exceed any of the threshold values set for each mode, the ventilation system 100 shifts to the mode that exceeds the threshold value. For example, when the temperature threshold for the temperature and humidity mode is 26°C and the humidity threshold is 80% (Figure 5), and the temperature and humidity sensor of the first sensor unit 21 detects 27°C and 85%, and the outside air temperature is 25°C, the ventilation system 100 shifts from normal operation to the temperature and humidity mode and performs exhaust operation at a low air volume. This will eliminate the heat buildup in the room. The threshold values set for each mode are stored in the memory accessible by the control unit 172.

[0039] Note that the four modes have a priority order, which from highest to lowest is: cooking temperature mode > CO2 mode > VOC·dust mode > temperature and humidity mode. For example, when the temperature and humidity sensor detects 27°C and 85% as described above, and the threshold for the CO2 mode is 1400 ppm, and the CO2 sensor of the first sensor unit 21 detects 1500 ppm, since the priority of the CO2 mode is higher than that of the temperature and humidity mode, the ventilation system 100 shifts to the CO2 mode and performs exhaust operation with an air volume according to the CO2 concentration.

[0040] Further, for example, when the CO2 sensor detects 1500 ppm as described above and the temperature sensor of the first sensor unit 21 detects 70°C when the threshold value of the temperature sensor is 65°C, since the priority of the cooking temperature mode is higher than that of the CO2 mode, the ventilation system 100 shifts to the cooking temperature mode and performs a circulation operation at an air volume corresponding to the detected temperature. When the detected temperature is high, an exhaust operation may be performed. As shown in FIG. 4 or FIG. 5, an exhaust operation and a circulation operation that are switched according to the mode are set, but they may be changed as appropriate. Also, the set threshold values in FIG. 5 are examples for explanation and are set as appropriate.

[0041] Note that it is preferable that the mode setting and the assignment of exhaust / circulation are different depending on the type of stove. For example, in the setting of a gas stove, only the VOC / dust mode may perform a circulation operation, and an exhaust operation may be performed in modes other than this mode. In the following description of this embodiment, the description will be based on the IH setting in an IH stove (Induction Heating).

[0042] Referring to the flowcharts of FIGS. 6 to 11, a control method in the ventilation system 100 will be described. Note that S in the flowchart indicates a step. FIG. 6 shows the main flow when the control unit 172 of the ventilation system 100 performs a hybrid operation. The control unit 172 starts a normal operation at S102 and reads the set threshold values for each mode from the memory. The control unit 172 refers to the sensor values detected by each of the sensor units 20 and acquired via the communication unit 171 at S104.

[0043] In S106, the control unit 172 compares the referenced sensor value with the threshold values set for each mode. If the sensor value exceeds the threshold value as a result of the comparison, the control unit 172 checks (reads from the memory) the priority order of the modes in S108. In S110, when the sensor value exceeds one threshold value, the control unit 172 shifts to the mode of the exceeded threshold value, or when the sensor value exceeds a plurality of threshold values, it shifts to the mode with the highest priority among the modes of the exceeded threshold values. In S112, the control unit 172 controls the exhaust / circulation switching damper 13 according to the shifted mode. For example, when the sensor value of the CO2 sensor of the first sensor unit 21 exceeds the threshold value of 1400 ppm, the exhaust / circulation switching damper 13 is controlled to switch from the circulation operation in the normal operation to the exhaust operation. Also, for example, when the sensor value of the dust sensor of the first sensor unit 21 exceeds the threshold value of 51 μm / m 3 , the exhaust / circulation switching damper 13 is controlled to continue the circulation operation.

[0044] In S114, the control unit 172 sets the air volume according to the magnitude of the sensor value. For example, when the CO2 concentration or the dust concentration is much higher than the threshold value, the fan 11 may be controlled with a strong air volume, or when it is close to the threshold value, the fan 11 may be controlled with a weak air volume. If the sensor value does not exceed the threshold value as a result of the comparison in S106, the control unit 172 maintains the normal operation in S130 and skips S108 to S114.

[0045] Next, in S116, the control unit 172 determines whether the current operation mode is the cooking temperature mode or the VOC / dust mode. If it is the cooking temperature mode or the VOC / dust mode, the control unit 172 performs the temporary exhaust setting process of S200. If it is not the cooking temperature mode or the VOC / dust mode, S200 is skipped. Note that S200 will be described later. In S118, the control unit 172 determines whether there is an operation change instruction from the operation switch 30 by the user. If there is an operation change instruction, the control unit 172 ends the hybrid operation and changes to the instructed operation state in S120. If there is no operation change instruction, S120 is skipped.

[0046] Referring to FIGS. 7 to 11, S200 will be described in detail. FIG. 7 shows a temporary exhaust setting process flow for controlling the circulation operation and the exhaust operation based on the sensor values at two time points before and after the deodorizing filter 15, which is a circulation filter. FIG. 8 shows a temporary exhaust setting process flow for controlling the circulation operation and the exhaust operation based on the air quality detected by the sensors of the sensor unit 20 at at least two time points. FIG. 9 shows a temporary exhaust setting process flow for controlling the circulation operation and the exhaust operation based on the air quality detected by the VOC sensors of the sensor unit 20 at at least two time points. FIG. 10 shows a temporary exhaust setting process flow for controlling the circulation operation and the exhaust operation based on the sensor values of the first sensor unit 21 arranged near the range hood 10 and the second sensor unit 22 arranged at a position away from the range hood 10. FIG. 11 shows a temporary exhaust setting process flow when controlling the circulation operation and the exhaust operation based on the air quality detected by the sensors of the first sensor unit 21 at two time points with different intervals. Note that all of these processes are processes in which the control unit 172 refers to at least two pieces of air quality information to control the circulation operation and the exhaust operation.

[0047] Referring to FIG. 7, in the ventilation system 100, a temporary exhaust setting process will be described when there are a pre-deodorization filter sensor 24 (first air quality sensor) located upstream of the air flow of the deodorization filter 15 where the range hood 10 is a circulation filter, and a post-deodorization filter sensor 25 (second air quality sensor) located downstream of the deodorization filter 15. Specifically, the pre-deodorization filter sensor 24 is on the flue between the fan 11 and the oil collection filter 12, that is, on the air flow path where air flows in both the exhaust operation and the circulation operation. The post-deodorization filter sensor 25 is between the deodorization filter 15 and the circulation air outlet 181, that is, on the air flow path immediately after passing through the deodorization filter 15 during the circulation operation (see FIG. 2). The pre-deodorization filter sensor 24 detects the air quality of the air before passing through the deodorization filter 15, and the post-deodorization filter sensor 25 detects the air quality of the air after passing through the circulation filter.

[0048] When the current operation mode is the cooking temperature mode or the VOC / dust mode, the control unit 172 acquires and refers to the sensor values of the pre-deodorization filter sensor 24 and the post-deodorization filter sensor 25 in S202. After waiting for a predetermined wait time in S204, the control unit 172 acquires and refers to the sensor values of the pre-deodorization filter sensor 24 and the post-deodorization filter sensor 25 again in S206. That is, the control unit 172 refers to both the sensor values of the pre-deodorization filter sensor 24 and the post-deodorization filter sensor 25 at two time points. The predetermined wait time is determined as appropriate, but about several seconds to more than ten seconds is preferable.

[0049] The control unit 172 compares the sensor values referred to in S202 and S206 in S208, and determines in S210 whether the sensor values are in a converged state. Whether it is in a converged state is determined as follows. The control unit 172 compares the difference between the sensor value detected by the pre-deodorizing filter sensor 24 and the sensor value detected by the post-deodorizing filter sensor 25 at the time of S202 (this is referred to as the first difference) with the difference between the sensor value detected by the pre-deodorizing filter sensor 24 and the sensor value detected by the post-deodorizing filter sensor 25 at the time of S206 (this is referred to as the second difference). If the second difference is smaller than the first difference, it is determined that the state is converged. Conversely, if the second difference is approximately equal to the first difference or the second difference is larger than the first difference, the control unit 172 determines that it is in an equilibrium / diverging state.

[0050] When it is determined that the state is converged, since the control unit 172 tends to improve the indoor air quality to a good state even in the current operating state, it maintains, for example, the VOC / dust mode which is the current operating state, i.e., the circulation operation. On the other hand, when it is determined that the state is in equilibrium / diverging, the control unit 172 refers to the sensor values of the temperature and humidity sensors of the first sensor unit 21 and the third sensor unit 23 in S214 and compares whether the temperature difference between the indoor and outdoor is within ±2°C. If the temperature difference is not within ±2°C, since it is not preferable to let the outdoor air enter the indoor in the current operating state, the control unit 172 maintains the circulation operation which is the current operating state in S212. If the temperature difference is within ±2°C, since the control unit 172 cannot improve the indoor air quality to a good state even if the current operating state is continued in S216, and since the indoor becomes negative pressure and the indoor temperature does not fluctuate significantly even if the outdoor air enters the indoor, it controls to switch to the exhaust operation. Note that when it is determined that the state is in equilibrium / diverging, it may be controlled to switch to the exhaust operation without referring to and comparing the sensor values of the temperature and humidity sensors of the first sensor unit 21 and the third sensor unit 23 (i.e., skipping S214).

[0051] In this embodiment, it is assumed that the circulation operation is being performed in the cooking temperature mode or the VOC / dust mode. However, the present invention is not limited to this. For example, in these modes, although the circulation operation is mainly performed, a circulation exhaust mixed operation may be performed in which the exhaust operation is simultaneously performed with a small air volume. In this case, when the control unit 172 determines that it is in a converged state, it maintains the current circulation exhaust mixed operation. When it determines that it is in an equilibrium / divergent state, it controls to increase the air volume of the exhaust operation, or decrease the air volume of the circulation operation, or perform a circulation exhaust mixed operation that performs both. Note that increasing the air volume of the exhaust operation means, for example, changing the current exhaust air volume from a weak air volume to a medium air volume or a strong air volume. Decreasing the air volume of the circulation operation means, for example, changing the current circulation air volume from a weak air volume to a very weak air volume or setting the air volume to zero (that is, stopping the circulation exhaust mixed operation and switching to only the exhaust operation). Further, in the circulation exhaust mixed operation, the control unit 172 may control not only the increase / decrease of the air volume as described above, but also by the opening ratio of the exhaust / circulation switching damper 13. Here, the opening ratio means that when the exhaust / circulation switching damper 13 can be controlled at 11 levels of angles from 0 to 10 from fully closed to fully open, the opening ratio of fully closed is 0 / 10, and the opening ratio of fully open is 10 / 10. For example, when the control unit 172 performs the exhaust operation, the opening ratio of the damper on the left side in FIG. 2(C) is 10 / 10, and the opening ratio of the damper on the right side shown in the figure is 0 / 10. When performing the circulation operation, the opening ratio of the damper on the left side shown in the figure is 0 / 10, and the opening ratio of the damper on the right side shown in the figure is 10 / 10. In the circulation exhaust mixed operation, when the control unit 172 initially controls with the opening ratio of the damper on the left side in FIG. 2(C) being 2 / 10 and the opening ratio of the damper on the right side shown in the figure being 8 / 10, in S216, the opening ratio of the damper on the left side in FIG. 2(C) is set to 8 / 10, and the opening ratio of the damper on the right side shown in the figure is set to 2 / 10, and the control is performed to increase the flow rate ratio of the damper for exhaust and decrease the flow rate ratio of the damper for circulation. Note that decreasing the flow rate ratio of the damper for circulation includes setting the opening ratio of the damper on the right side shown in the figure to 0 / 10, and includes forming only a flow path in which the air sucked by the fan 11 flows toward the exhaust port 182 connected to the outdoor exhaust duct.

[0052] As described above, the control unit 172 compares the differences in the air quality information detected at two time points before and after the deodorizing filter 15, which is a circulation filter. If the differences remain substantially equal or increase, continuing the same operating state would result in wasted operation and lead to energy loss. Therefore, the control unit controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation.

[0053] In this way, by controlling the circulation operation and the exhaust operation based on the sensor values at two time points before and after the deodorizing filter 15, it is possible to more accurately and timely determine the state of the indoor air quality based on the state of generation of pollutants removed and reduced by the circulation filter and the collection state by the circulation filter. For example, depending on the state of generation of pollutants, if pollutants exceeding the filter performance of the circulation filter are generated, the pollutants can be detected even downstream of the circulation filter, so it can be detected that a large amount of pollutants are generated. Also, depending on the collection state by the circulation filter, if the circulation filter becomes clogged or deteriorated, the same level of pollutants can be detected upstream and downstream of the circulation filter, so unnecessary circulation operation can be avoided.

[0054] Therefore, although the above description mentions detecting at two time points by the pre-deodorizing filter sensor 24 and the post-deodorizing filter sensor 25 before and after the deodorizing filter 15, which is a circulation filter, it shows that the circulation operation and the exhaust operation may be controlled based on the comparison of the two (sensor values at one time point) sensor values of the pre-deodorizing filter sensor 24 and the post-deodorizing filter sensor 25. According to this, by controlling the circulation operation and the exhaust operation based on the comparison of the air quality information before and after passing through the circulation filter, it is possible to more accurately and timely determine the state of the indoor air quality than detecting with a single sensor.

[0055] Also, as described above, when the difference in air quality information detected at two points before and after the deodorizing filter 15 is approximately equal, it was stated that the control is to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. However, even when the difference is approximately equal (equilibrium state), if both differences are smaller than a predetermined difference, the current operating state is maintained, and if both differences are larger than the predetermined difference, the control may be to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. Since it can be said that the equilibrium state is the normal state when the amount of generated pollutants is small, control may be performed to carry out the exhaust operation only when both differences are large, that is, when the amount of generated pollutants is large.

[0056] According to this, by comparing the differences in air quality information detected at two points, and controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation only when the differences remain approximately equal and both differences are larger than a predetermined difference, the state of the indoor air quality can be accurately and timely determined. The predetermined difference is determined as appropriate. For example, when the difference is large, it is the difference when one sensor value corresponds to a strong operation of VOC Index 450 or more and the other sensor value is near the threshold value (200), and when the difference is small, it is the difference when one sensor value corresponds to a weak operation of VOC Index 400 or less and the other sensor value is near the threshold value (200).

[0057] Note that the control unit 172 controls the circulation operation and the exhaust operation based on the comparison of the sensor values (air quality information) detected by the temperature and humidity sensors of the first sensor unit 21 (air quality sensor) and the third sensor unit 23 (outdoor air quality information acquisition means) in S214. In this way, by controlling the circulation operation and the exhaust operation based on the comparison of the outdoor and indoor air quality information, the air quality of the indoor air can be improved by using the air quality of the outdoor air. Also, as described above, since the switching from the circulation operation to the exhaust operation occurs when the temperature difference between the indoor and outdoor is within ±2°C, even if the outdoor air quality enters the indoor, the air quality of the indoor air can be improved without imposing an energy burden for re-air conditioning.

[0058] Referring to FIG. 8, in the ventilation system 100, a temporary exhaust setting process will be described when the VOC / dust sensor of the first sensor unit 21 controls the circulation operation and the exhaust operation based on the air quality (VOC / dust concentration) detected at at least two time points. In the following embodiments, the detected air quality will be described as the VOC / dust concentration. However, of course, the process may be performed based on either the VOC index value or the dust concentration, which is one of the air quality information. Specifically, since the first sensor unit 21 is provided in the range hood 10, the control unit 172 controls the operation based on the VOC / dust concentration of the air in the cooking space such as the kitchen.

[0059] When the operation mode is the cooking temperature mode or the VOC / dust mode, in S220, the control unit 172 acquires and refers to the VOC / dust concentration, which is the sensor value detected by the VOC / dust sensor of the first sensor unit 21 at that time point (time point X1). After waiting for a predetermined waiting time in S222, in S224, the control unit 172 acquires and refers to the VOC / dust concentration detected again by the first sensor unit 21 at that time point (time point X2). That is, the control unit 172 refers to the VOC / dust concentrations of the first sensor unit 21 at two time points. The predetermined waiting time is determined as appropriate, but about several seconds to more than ten seconds is preferable. Also, the predetermined waiting time may be changed. For example, the waiting time may be gradually shortened. Thereby, the accuracy of calculating (predicting) the time to fall below the threshold value from the slope can be improved.

[0060] In S226, the control unit 172 calculates the slope from the VOC and dust concentration at time point X1 and the VOC and dust concentration at time point X2 after time point X1, and starts counting whether the slope is positive or negative. In S228, the control unit 172 determines whether it has occurred three consecutive times that the VOC and dust sensor detected at time point X2 is lower than the VOC and dust concentration detected at time point X1, that is, whether the slope is negative three consecutive times. If the slope does not become negative three consecutive times, the control unit 172 returns to S220 and repeats S220 - S228 until the slope becomes negative three consecutive times. Note that in S228, since it is only necessary to determine that the VOC and dust concentration is decreasing, it may be determined by whether the average value of three times becomes negative, or it may be five times instead of three times.

[0061] If the slope becomes negative three consecutive times, in S230, the control unit 172 determines whether the change amount (gradient) of the slope is within 5%. If it is within 5%, in S232, since the current operating state cannot reduce the indoor VOC and dust concentration and improve the air quality even if continued, the control unit 172 switches to the exhaust operation. If it exceeds 5%, in S234, the control unit 172 calculates (predicts) the time (time point Xn) when it drops below the threshold value of the VOC and dust concentration (VOC (index value) = 201, dust = 51 [μg / m 3 (see Figure 5)) below. This calculation may be obtained by extrapolation using a linear equation or a logarithmic equation.

[0062] In S236, the control unit 172 determines whether the time point Xn is within 600 seconds from now, that is, whether it is expected that the VOC and dust concentration will drop below the threshold value within 600 seconds. If it is determined that the VOC and dust concentration is expected to drop below the threshold value within 600 seconds, in S238, since the current operating state also tends to quickly reduce the indoor VOC and dust concentration to a good state, the control unit 172 maintains the current operating state, that is, the VOC and dust mode which is the circulation operation.

[0063] On the other hand, when it is determined that the expected time exceeds 600 seconds, in S239, the control unit 172 controls to switch to the exhaust operation because it would take a long time to reduce the indoor VOC and dust concentrations to a good state even if the current operation state is continued. Note that the threshold value of the change amount (5% in the above example) can be determined as appropriate, but it is preferably determined based on whether it is a change amount that can be determined to be improved by the circulation operation. Also, the elapsed time for prediction (600 seconds in the above example) can be determined as appropriate, but a shorter time is preferable from the perspective of energy loss.

[0064] In this embodiment, it is premised that the circulation operation is being performed in the cooking temperature mode or the VOC / dust mode, but it is not limited to this. For example, although the circulation operation is mainly performed in these modes, a circulation exhaust mixed operation in which the exhaust operation is performed simultaneously with a small air volume may be performed. In this case, when the control unit 172 determines that the change amount of the slope exceeds 5% and the VOC / dust concentration becomes equal to or less than the threshold value within 600 seconds, the control unit 172 maintains the current circulation exhaust mixed operation. When it is determined that the change amount of the slope is within 5% or the VOC / dust concentration does not become equal to or less than the threshold value within 600 seconds and it is not expected that a predetermined air quality can be achieved, the control unit 172 may control to perform a circulation exhaust mixed operation in which the air volume of the exhaust operation is increased, or the air volume of the circulation operation is decreased, or both. Further, in the circulation exhaust mixed operation, the control unit 172 may control not only by increasing / decreasing the air volume as described above, but also by the opening ratio of the exhaust / circulation switching damper 13. In the circulation exhaust mixed operation, when the control unit 172 initially controls with the opening ratio of the damper on the left side in FIG. 2(C) being 2 / 10 and the opening ratio of the damper on the right side shown in the figure being 8 / 10, in S216, the control unit 172 increases the flow rate ratio of the damper for exhaust so that the opening ratio of the damper on the left side in FIG. 2(C) is 8 / 10 and the opening ratio of the damper on the right side shown in the figure is 2 / 10, and decreases the flow rate ratio of the damper for circulation.

[0065] Note that, in this figure, the VOC and dust concentrations are used as examples for explanation, but it is not limited thereto. For example, it may be the CO2 concentration detected by a CO2 sensor, or the temperature and humidity detected by a temperature and humidity sensor. When it is the CO2 concentration, dust concentration, or VOC concentration, it can be said that a negative slope is a preferable tendency. Therefore, it can be said that the fact that these slopes are negative tends to improve the air quality to a good state. On the other hand, when it is the temperature or humidity, it cannot necessarily be said that a negative slope is a preferable tendency. Therefore, the tendency to approach the preferable temperature and humidity is regarded as the tendency to improve the air quality to a good state (improvement tendency), and the tendency to deviate from the preferable temperature and humidity is regarded as the tendency to deteriorate the air quality (deterioration tendency).

[0066] Thus, in the time-series data which is the air quality information continuously detected several times by the air quality sensor, when it is determined that the air quality information at the second time point (X2 time point) is in an improvement tendency compared to the air quality information at the first time point (X1 time point) before the second time point, and even if the improvement tendency continues, it is not expected that a predetermined air quality (in the above example, the VOC and dust concentrations are VOC (index value) = 201, dust = 51 [μg / m 3 ) can be achieved within a predetermined time (600 seconds in the above example), it may be controlled to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation.

[0067] According to this, when the time-series change of the air quality information is in an improvement tendency, but even if the improvement tendency continues, it is not expected that a predetermined air quality can be achieved within a predetermined time, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, it is possible to achieve an early realization of a comfortable air quality environment.

[0068] Referring to FIG. 9, in the ventilation system 100, a temporary exhaust setting process will be described when the circulation operation and the exhaust operation are controlled based on the air quality (VOC concentration) detected by the VOC sensor of the first sensor unit 21 at at least two time points. Specifically, since the first sensor unit 21 is provided in the range hood 10, the control unit 172 controls the operation based on the VOC concentration of the air in the cooking space such as the kitchen. Note that this example shows the process in a state where the VOC concentration is very high.

[0069] When the operation mode is the cooking temperature mode or the VOC / dust mode, the control unit 172 determines in S240 whether the sensor value detected by the VOC sensor of the first sensor unit 21 is 300 or more. If it is less than 300, this process is repeated. When it reaches 300 or more, the control unit 172 obtains and refers to the VOC concentration, which is the sensor value detected by the VOC sensor of the first sensor unit 21 at that time (time point X1) in S242. After waiting for a predetermined wait time in S244, the control unit 172 obtains and refers to the VOC concentration detected by the first sensor unit 21 again at that time (time point X2) in S246. That is, the control unit 172 refers to the VOC concentrations of the first sensor unit 21 at two time points.

[0070] In S248, the control unit 172 calculates the slope from the VOC concentration at time point X1 and the VOC concentration at time point X2 after time point X1, and starts counting whether the slope is positive or negative. In S250, the control unit 172 determines whether it has occurred three times in a row that the VOC concentration detected at time point X2 is higher than the VOC concentration detected at time point X1, that is, whether the slope is positive three times in a row. If the slope does not become positive three times in a row, the control unit 172 returns to S242 and repeats S242 to S250 until the slope becomes positive three times in a row.

[0071] When the slope becomes positive three times in a row, in S252, the control unit 172 calculates the slope (angle) of the inclination, and in S254, determines whether the calculated angle of the slope is 35 degrees or more. When the angle of the slope is 35 degrees or more, in S258, since continuing the current operating state cannot reduce the indoor VOC concentration or improve the air quality to a good level or takes a long time, the control unit 172 switches to the exhaust operation. When it is less than 35 degrees, in S256, since the current operating state is also in a state corresponding to the increase in the indoor VOC concentration, the control unit 172 maintains the current operating state, that is, the VOC / dust mode which is the circulation operation.

[0072] In addition, when the control unit 172 refers to the air quality information of the VOC concentration detected by the VOC sensor of the first sensor unit 21 at at least two time points and determines that the air quality is deteriorating, that is, the VOC concentration is increasing, and when the deterioration rate (increase rate) of the deterioration tendency is greater than a predetermined rate, the control unit 172 may control to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. In this way, when the air quality information detected by the air quality sensor at two time points has a deterioration tendency greater than a predetermined rate, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, the circulation operation and the exhaust operation can be controlled in a timely manner according to the indoor air quality. Note that the fact that the air quality detected at two time points is deteriorating includes both the case where the second time point is increasing compared to the first time point and thus has an increasing tendency, and the case where both the first time point and the second time point are increasing compared to a time point earlier than this and thus have an increasing tendency.

[0073] As described above, the control unit 172 may control the circulation operation and the exhaust operation based on the time-series change amount of the air quality information detected by the air quality sensor. In this way, by controlling the circulation operation and the exhaust operation based on the time-series change amount of the air quality information detected at at least two time points, it is possible to make a more accurate and timely determination.

[0074] Referring to FIG. 10, in the ventilation system 100, a temporary exhaust setting process will be described when the circulation operation and the exhaust operation are controlled based on the air quality (VOC / dust concentration) detected by two sensors, namely, the VOC / dust sensor of the first sensor unit 21 arranged in the kitchen and the VOC / dust sensor of the second sensor unit 22 arranged in the living room. Specifically, the first sensor unit 21 is a sensor (the fourth air quality sensor) installed near the range hood 10, and the second sensor unit 22 is a sensor (the third air quality sensor) installed at a position spatially connected farther from the first sensor unit 21 starting from the range hood 10. When the range hood 10 performs a ventilation operation, air is introduced from the air supply port in the living room and an air flow is formed toward the range hood 10. Therefore, the first sensor unit 21 is located on the flow path from the second sensor unit 22 to the range hood 10.

[0075] When the operation mode is the cooking temperature mode or the VOC / dust mode, in S260, the control unit 172 constantly monitors the VOC / dust sensor of the second sensor unit 22 and detects that the sensor value has exceeded an arbitrary threshold of the VOC / dust concentration (this point in time is defined as the time point X1 in FIG. 12). Note that the arbitrary threshold is a value used to estimate the distance between the first sensor unit 21 and the second sensor unit 22, so it may be below the threshold for the circulation operation, and it is not necessary for the detection time point to be on the rising gradient. In FIG. 12, the curve closer to the origin in the X-axis direction indicating time shows the measured value by the second sensor unit 22, and the curve on the right side away from the origin shows the measured value by the first sensor unit 21.

[0076] Next, in S262, the control unit 172 causes the VOC / dust sensor of the second sensor unit 22 to detect the VOC / dust concentration at that time (this time is set as time point X2 in FIG. 12). After waiting for a predetermined wait time in S264, in S266, the control unit 172 acquires and refers to the VOC / dust concentration detected by the second sensor unit 22 at that time (this time is set as time point X3 in FIG. 12). That is, the control unit 172 refers to the VOC / dust concentrations of the second sensor unit 22 at two time points triggered by the detected VOC / dust concentration exceeding an arbitrary threshold. Note that the predetermined wait time is determined as appropriate, but is preferably about several seconds to ten-odd seconds.

[0077] In S268, the control unit 172 calculates the slope from the VOC / dust concentration at time point X2 and the VOC / dust concentration at time point X3 after time point X2, and starts counting whether the slope is positive or negative. In S270, the control unit 172 determines whether the VOC / dust concentration detected at time point X3 has become higher than the VOC / dust concentration detected at time point X2 three times in a row, that is, whether the slope has become positive three times in a row. If the slope does not become positive three times in a row, the control unit 172 returns to S262 and repeats S262 to S270 until the slope becomes positive three times in a row.

[0078] If the slope becomes positive three times in a row, in S272, the control unit 172 causes the VOC / dust sensor of the first sensor unit 21 to constantly monitor, and detects that this sensor value has exceeded the above-mentioned arbitrary threshold of the VOC / dust concentration (this time is set as time point X4 in FIG. 12). Next, in S274, based on the time at time point X1 and the time at time point X4, the control unit 172 calculates the time (delay time t) from when the VOC / dust sensor of the second sensor unit 22 detects an arbitrary threshold to when the VOC / dust sensor of the first sensor unit 21 detects the same arbitrary threshold. This delay time t indicates the distance between the first sensor unit 21 and the second sensor unit 22.

[0079] In S276, the control unit 172 determines whether the delay time t is within Z seconds. Note that Z seconds can be set within the range of about 10 to 30 seconds for a general residence. This Z seconds is preferably set in view of the time it takes for VOC generated by countertop cooking in the living room to diffuse or for the suction airflow generated by the operation of the range hood 10 to reach the vicinity of the range hood 10. If the delay time t is not within Z seconds, in S279, the control unit 172 determines that the distance between the first sensor unit 21 (kitchen space such as near the range hood) and the second sensor unit 22 (living space) is far, and it is assumed that it takes time for the VOC determined to be increasing in the living space in S270 to reach the vicinity of the range hood 10 due to the suction airflow. It is judged that pollutants may remain in the living space or the like if the circulation operation continues, and the operation is switched to the exhaust operation. If the delay time t is within Z seconds, in S278, since it is assumed that the VOC generation source is near the range hood 10 and the indoor VOC and dust concentrations can be maintained in a good state even in the current operation state, the VOC and dust mode, which is the current operation state, that is, the circulation operation, is maintained.

[0080] As described above, the control unit 172 may control the circulation operation and the exhaust operation based on the time difference between when the second sensor unit 22 detects air quality information of a predetermined arbitrary threshold value and when the first sensor unit 21 detects air quality information of a predetermined arbitrary threshold value. In this way, by controlling the circulation operation and the exhaust operation based on the time difference between when the air quality information of a predetermined threshold value is detected at a distant position and when the air quality information of a predetermined threshold value is detected in the vicinity, a comfortable environment can be constructed over a wide range indoors. By switching to the exhaust operation, the indoor pressure becomes negative, and outdoor air flows into the indoor through the air intake openings (supply and exhaust registers and gaps) in the house. The inflowing air forms an airflow that flows from the intake opening in the direction of the range hood due to the suction of the range hood. Thus, for example, when it is determined that pollutants are increasing in the living space far from the range hood, a comfortable air quality environment can be constructed early with the support of the airflow.

[0081] Further, when the control unit 172 determines that the air quality information detected by the second sensor unit 22 shows a deteriorating trend such as a continuous increase in the CO2 concentration when the air quality information is equal to or higher than a predetermined threshold, and the second sensor unit 22 detects air quality information equal to or higher than the predetermined threshold within a predetermined time after the air quality information detected by the first sensor unit 21 is detected to be the predetermined threshold, the control unit 172 may control to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation.

[0082] According to this, when the air quality sensor located upstream in the air flow path detects that the air quality information is the predetermined threshold, and within a predetermined time after that, the air quality sensor located downstream detects the same level of air quality information, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, a comfortable environment can be constructed over a wide range indoors.

[0083] Referring to FIG. 11, in the ventilation system 100, a temporary exhaust setting process will be described when the circulation operation and the exhaust operation are controlled based on the air quality detected by the sensors of the first sensor unit 21 at two different points in time with different intervals. Specifically, since the first sensor unit 21 is provided in the range hood 10, the control unit 172 controls the operation based on the air quality detected at different time intervals in a cooking space such as a kitchen.

[0084] When the operation mode is the cooking temperature mode or the VOC / dust mode, in S280, the control unit 172 accesses the memory that stores the sensor value detected by the air quality sensor of the first sensor unit 21. In S282, the control unit 172 refers to the sensor value stored in the memory at 10-second intervals. In S284, the control unit 172 calculates the slope based on two sensor values at 10-second intervals and starts counting whether the slope is positive or negative. In S286, the control unit 172 determines whether the slope has been negative three times in a row. If the slope has not been negative three times in a row, the control unit 172 returns to S280 and repeats S280 - S286 until the slope is negative three times in a row. Note that it may be determined that the average value of the three times has become negative.

[0085] When the slope has been negative three times in a row, in S288, the control unit 172 changes the interval of the sensor value used for reference to 5-second intervals and stores it in the memory. That is, when it is determined that the air quality is improving based on the air quality information detected by the air quality sensor of the first sensor unit 21 at at least two time points, the interval of the sensor value used for reference is shortened to 5-second intervals, which is half of the previous interval, and stored in the memory. In S290, the control unit 172 determines whether the sensor value has reached half of the peak value and the threshold value, or whether 300 seconds have elapsed since the start of the circulation mode. If this condition is not satisfied, the control unit 172 repeats until this condition is satisfied.

[0086] When this condition is satisfied, in S292, the control unit 172 refers to the latest three sensor values among the sensor values at 5-second intervals stored. That is, when the sensor values at two time points show an improving trend and that improving trend satisfies the above-mentioned predetermined condition, the control unit starts referring to the air quality information at a time interval shorter than the time interval it referred to before satisfying the predetermined condition. In S294, the control unit 172 calculates the average of the latest 15 seconds, that is, the latest three sensor values, and calculates (predicts) the time it takes to fall below the threshold value.

[0087] In S296, the control unit 172 determines whether the calculated time is within 600 seconds. If it is not within 600 seconds, in S299, the control unit 172 determines that even if the improving trend of the air quality detected at at least two time points at a short time interval continues, it is not expected that a predetermined air quality can be achieved within a predetermined time, and switches to the exhaust operation. If it is within 600 seconds, in S298, since the indoor air quality can be improved even in the current operation state, the control unit 172 maintains the current operation state, that is, the normal operation which is the circulation operation.

[0088] Note that in this embodiment, it is assumed that the circulation operation is being performed in the cooking temperature mode or the VOC / dust mode, but it is not limited thereto. For example, although the circulation operation is mainly performed in these modes, a circulation exhaust mixed operation may be performed in which the exhaust operation is simultaneously performed with a small air volume. In this case, even when the control unit 172 refers to the sensor value at a short time interval, if it determines that the sensor value does not fall below a desired threshold within 600 seconds and it is not expected that a predetermined air quality can be achieved, the control unit 172 may control to increase the air volume of the exhaust operation, or decrease the air volume of the circulation operation, or perform a circulation exhaust mixed operation that performs both of these.

[0089] In this way, although the time-series change of the air quality information shows an improving trend, when it is not expected that a predetermined air quality can be achieved within a predetermined time even if the improving trend detected at a shorter and finer interval continues, by controlling to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation, the calculation accuracy can be improved and the realization of good air quality can be achieved earlier.

[0090] As described above, in the ventilation system 100, the control unit 172 refers to at least two pieces of air quality information and controls the circulation operation and the exhaust operation. In this way, by controlling the circulation operation and the exhaust operation based on at least two pieces of air quality information, it is possible to provide a ventilation system 100 that controls the circulation operation and the exhaust operation in a timely manner according to the indoor air quality, reduces energy loss, and constructs a comfortable environment, and a method for controlling the ventilation system 100.

[0091] Note that the present invention is not limited to the illustrated embodiments, and can be implemented with configurations that do not deviate from the content described in each item of the claims. That is, although the present invention is mainly illustrated and described with respect to specific embodiments, various modifications can be made by those skilled in the art to the above-described embodiments in terms of quantity and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention.

Explanation of Signs

[0092] 100 Ventilation system 10 Range hood (ventilation device) 11 Exhaust fan 12 Oil collection filter 13 Exhaust / circulation switching damper 14 Electrostatic precipitator 15 Deodorizing filter (circulation filter) 16 Input / output interface 171 Communication unit 172 Control unit 181 Circulation air outlet 182 Exhaust port 19 Hood part 20 Sensor unit (air quality sensor) 21 First sensor unit 22 Second sensor unit 23 Third sensor unit 24 Sensor before deodorizing filter 25 Sensor after deodorizing filter 30 Operation switch 40 Smartphone 50 Cloud server

Claims

1. A function of performing an exhaust operation to exhaust the inhaled air outdoors, A function of performing a circulation operation to return the inhaled air indoors through a circulation filter, An air quality sensor for detecting the air quality of the indoor air to be inhaled, A control unit for controlling the circulation operation and the exhaust operation based on the air quality information detected by the air quality sensor, Comprising, The control unit controls the circulation operation and the exhaust operation by referring to at least two pieces of air quality information, A ventilation system.

2. The air quality sensor is a first air quality sensor for detecting the air quality of the air before passing through the circulation filter, Further comprising a second air quality sensor for detecting the air quality of the air after passing through the circulation filter, The ventilation system according to claim 1, wherein the control unit controls the circulation operation and the exhaust operation based on a comparison of the air quality information detected by the first air quality sensor and the second air quality sensor.

3. The control unit compares a first difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a first time point, and a second difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a second time point after the first time point. When the second difference is substantially equal to or greater than the first difference, the control unit controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. The ventilation system according to claim 2.

4. The control unit compares a first difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a first time point, and a second difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a second time point after the first time point. When the second difference is greater than the first difference, the control unit controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. The ventilation system according to claim 2.

5. The control unit compares a first difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a first time point, and a second difference between two pieces of air quality information detected by the first air quality sensor and the second air quality sensor at a second time point after the first time point. When the second difference is substantially equal to the first difference and both differences are greater than a predetermined difference, the control unit controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. The ventilation system according to claim 2.

6. The ventilation system according to claim 1, wherein the control unit controls the circulation operation and the exhaust operation based on the amount of change over time of the air quality information detected by the air quality sensor.

7. The control unit determines that the air quality information at the second time point among the time series data of the air quality information detected by the air quality sensor shows an improving trend compared to the air quality information at the first time point before the second time point, and when it is not expected that a predetermined air quality can be achieved within a predetermined time even if this improving trend continues, controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. The ventilation system according to claim 6.

8. The control unit determines that the air quality shows an improving trend with reference to the air quality information of the air quality detected by the air quality sensor at at least two time points, and when this improving trend satisfies a predetermined condition, starts referring to the air quality information at a time interval shorter than the time interval referred to before satisfying the predetermined condition, and when it is not expected that a predetermined air quality can be achieved within a predetermined time even if the improving trend of the air quality detected at at least two time points continues at this short time interval, controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. The ventilation system according to claim 6.

9. The control unit determines that the air quality shows a deteriorating trend with reference to the air quality information of the air quality detected by the air quality sensor at at least two time points, and when the deterioration rate of this deteriorating trend is greater than a predetermined rate, controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation. The ventilation system according to claim 1.

10. The air quality sensor is a fourth air quality sensor that detects the air quality installed near the ventilation device and a third air quality sensor installed at a position farther from the fourth air quality sensor. The control unit controls the circulation operation and the exhaust operation based on the time difference between when the third air quality sensor detects air quality information of a predetermined threshold value and when the fourth air quality sensor detects air quality information of a predetermined threshold value. The ventilation system according to claim 1.

11. The fourth air quality sensor is located on the flow path from the third air quality sensor to the ventilation device. The control unit controls to increase the air volume of the exhaust operation and / or decrease the air volume of the circulation operation when it is determined that the air quality information detected by the third air quality sensor shows a deteriorating trend at a level equal to or higher than a predetermined threshold value, and the fourth air quality sensor detects air quality information equal to or higher than the predetermined threshold value within a predetermined time after detecting that the air quality information detected by the third air quality sensor is the predetermined threshold value. The ventilation system according to claim 10, characterized in that.

12. Further comprising outdoor air quality information acquisition means for acquiring outdoor air quality information, The control unit controls the circulation operation and the exhaust operation based on a comparison between the air quality information acquired by the outdoor air quality information acquisition means and the air quality information detected by the air quality sensor. The ventilation system according to any one of claims 1 to 11, characterized in that.

13. A function of performing an exhaust operation for exhausting the inhaled air outdoors, A function of performing a circulation operation for returning the inhaled air indoors through a circulation filter, An air quality sensor for detecting the air quality of the indoor air to be inhaled, In a ventilation system comprising: A method for controlling a circulation operation and an exhaust operation based on air quality information detected by the air quality sensor, Controlling the circulation operation and the exhaust operation by referring to at least two pieces of air quality information detected by the air quality sensor, Method.

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