Air volume control system, range hood, controller, and computer program

Abstract

To provide a technology capable of appropriately controlling an air volume regardless of season or weather.SOLUTION: An air volume control system 1 disclosed in the present disclosure comprises a relative humidity sensor 24 that detects a humidity in a room, and a controller 22 that controls an air volume of a ventilation fan 4 that ventilates the room. The controller 22 comprises a processing unit 26 that executes: a control process 26a that controls the air volume based on the detected humidity DH obtained based on the output of the relative humidity sensor 24 and the difference ΔH between the detected humidity DH and a reference value RH; and an update process 26b that updates the reference value RH so that the difference ΔH becomes smaller.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an airflow control system, a range hood, a control device, and a computer program. [Background technology]

[0002] Patent Document 1 discloses a range hood. This range hood is a ventilation device that has an airflow generator such as a sirocco fan or a turbo fan built in and takes in indoor air through an opening provided in the hood and exhausts it. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-115825 A Summary of the Invention [Problem to be solved by the invention]

[0004] The air volume of the range hood is sometimes automatically controlled based on the output of a humidity sensor that detects the humidity in the room. In controlling the air volume based on the output of a humidity sensor, a threshold value may be set for the relative humidity, and the air volume may be controlled based on a comparison between the current relative humidity and the threshold value.

[0005] Here, the relative humidity can vary greatly depending on the season. For example, the average relative humidity in January in the Kanto region is about 45%, and the average relative humidity in August is about 70%. Therefore, if the air volume is controlled based on a comparison between the current relative humidity and a threshold value, the degree of air volume adjustment will differ depending on the season, and there is a risk that appropriate control will not be possible. This phenomenon also occurs due to humidity differences caused by weather. In other words, air volume control based on a comparison between the current relative humidity and a threshold value may not be performed appropriately due to the influence of the season and weather. [Means for solving the problem]

[0006] The air volume control system disclosed herein includes a humidity sensor that detects indoor humidity, and a control device that controls the air volume of a ventilation fan that ventilates the room. The control device includes a processing unit that executes a control process that controls the air volume based on a difference between a detected humidity obtained based on an output of the humidity sensor and a reference value, and an update process that updates the reference value so as to reduce the difference. Effect of the Invention

[0007] According to the present disclosure, the air volume can be appropriately controlled regardless of the season or weather. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a partially cutaway side view of a range hood. [Diagram 2] FIG. 2 is a perspective view of the range hood. [Diagram 3] FIG. 3 is a block diagram showing an example of an air volume control system. [Figure 4] FIG. 4 is a flowchart illustrating an example of an update process performed by the processing unit. [Diagram 5] FIG. 5 is a flowchart illustrating an example of a control process performed by the processing unit. [Figure 6] FIG. 6 is a graph showing an example of changes in the detected humidity and the reference value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, the contents of the embodiment will be listed and described. [Outline of the embodiment]

[0010] (1) The present disclosure provides an airflow control system that includes a humidity sensor that detects indoor humidity and a control device that controls the airflow of a ventilation fan that ventilates the room. The control device includes a processing unit that executes a control process that controls the airflow based on a difference between a detected humidity obtained based on an output of the humidity sensor and a reference value, and an update process that updates the reference value so as to reduce the difference.

[0011] According to the above configuration, the reference value is updated so that the difference becomes smaller, so that the reference value can be changed to follow the detected humidity that changes from moment to moment. Therefore, if the update rate of the reference value is adjusted so that it cannot follow humidity changes due to cooking work, etc., the reference value that is the basis for controlling the air volume can be made to follow the stable humidity that changes depending on the season, weather, etc. Also, the difference can be increased to accommodate a sudden increase in humidity due to work, etc. As a result, the air volume can be appropriately controlled regardless of the season or weather.

[0012] (2) In the air volume control system of (1) above, when the update process is a process of repeating either a subtraction process in which an updated reference value is obtained by subtracting a predetermined subtraction value from the reference value when the reference value is greater than the detected humidity, or an addition process in which an updated reference value is obtained by adding a predetermined addition value to the reference value when the reference value is equal to or less than the detected humidity, it is preferable that a first interval provided after the addition process is longer than a second interval provided after the subtraction process. In this case, the repetition interval when the addition process is repeated is longer than the repetition interval when the subtraction process is repeated, which allows the change in the difference when the addition process is repeated to be more gradual than the change in the difference when the subtraction process is repeated. This allows the difference when the detected humidity increases to be relatively larger than the difference when the detected humidity decreases, and allows a steep increase in relative humidity to be effectively reflected in the difference. As a result, the air volume can be more appropriately controlled in response to a steep increase in relative humidity.

[0013] (3) In the air volume control system of (2) above, the update process may further include a process of setting the updated reference value to a predetermined lower limit value when the updated reference value reaches the lower limit value. In this case, it is possible to prevent the reference value from decreasing more than necessary.

[0014] (4) In the air volume control system of (3) above, the update process may further include a process of limiting execution of the addition process and the subtraction process for a predetermined period of time after the updated reference value is set to the lower limit value. In this case, when the addition process is performed after a predetermined period of time has elapsed, the reference value has dropped sufficiently, so that the response of the airflow control to the increase in the detected humidity can be made quick.

[0015] (5) In the air volume control system of (2) above, the update process may further include a process of setting the updated reference value to a predetermined upper limit value when the updated reference value reaches the upper limit value. In this case, it is possible to prevent the reference value from increasing more than necessary, thereby ensuring an appropriate difference between the reference value and the detected humidity when the detected humidity increases, and allowing the airflow control to respond appropriately to the increase in the detected humidity.

[0016] (6) From another viewpoint, the present disclosure is a range hood. The range hood includes a ventilation fan for ventilating a room, a humidity sensor for detecting the humidity in the room, and a control device for controlling an air volume of the ventilation fan. The control device includes a processing unit for executing a control process for controlling the air volume based on a difference between a detected humidity obtained based on an output of the humidity sensor and a reference value, and an update process for updating the reference value so as to reduce the difference.

[0017] (7) From another viewpoint, the present disclosure provides a control device for controlling an air volume of a ventilation fan for ventilating a room. The control device includes a processing unit that executes a control process for controlling the air volume based on a difference between a detected humidity obtained based on an output of a humidity sensor that detects the humidity in the room and a reference value, and an update process for updating the reference value so as to reduce the difference.

[0018] (8) From another viewpoint, the present disclosure is a computer program for causing a computer to execute a process for controlling an air volume of a ventilation fan that ventilates a room, the computer program causing the computer to execute a step of controlling the air volume based on a difference between a detected humidity obtained based on an output of a humidity sensor that detects the humidity in the room and a reference value, and a step of updating the reference value so as to reduce the difference.

[0019] [Details of the embodiment] Hereinafter, preferred embodiments will be described with reference to the drawings. At least a part of each of the embodiments described below may be combined in any manner.

[0020] [Overall structure of range hood] Fig. 1 is a partially cutaway side view of a range hood 1. Two arrows in Fig. 1 indicate the height direction and depth direction of the range hood 1, respectively. Fig. 2 is a perspective view of the range hood 1. Three arrows in Fig. 2 indicate the height direction, width direction, and depth direction of the range hood 1, respectively. The range hood 1 is a ventilation device including a ventilation unit 10 and an air volume control system 20. The ventilation unit 10 has a function of ventilating the room in which the range hood 1 is installed. The ventilation unit 10 of this embodiment can be installed with its back surface in contact with a wall surface inside a room (wall-mounted type). The ventilation unit 10 may also be mounted on a wall by its side surface. The ventilation unit 10 may also be installed in contact with a ceiling without contacting a wall surface (ceiling-mounted type). The ventilation unit 10 has an air blower box 3 with a built-in ventilation fan 4 that is an airflow generator, a flat box-shaped hood 2 with an open bottom attached to the lower part of the air blower box 3, and a straightening plate 9. The ventilation box 3 is provided between the hood 2 and a ventilation opening (not shown) that communicates between the inside and outside of the room.

[0021] The hood 2 has an inner panel 5. The inner panel 5 has an opening 5A for taking air into the ventilation box 3. A filter 6 is provided in the opening 5A. The periphery of the opening 5A of the inner panel 5 has a surface shape that is horizontal or approximately horizontal when the range hood 1 is installed. The inner panel 5 is formed from a plate material made of a magnetic material, for example, structural steel or the like.

[0022] Air is taken into the blower box 3 by an airflow generated by the ventilation fan 4. The ventilation fan 4 has a fan body 4a and a motor 4b. The fan body 4a is driven to rotate by the motor 4b. The ventilation fan 4 generates an airflow for ventilation by the rotation of the fan body 4a.

[0023] The straightening plate 9 is attached to the rear edge in the depth direction of the hood 2. The straightening plate 9 straightens the flow of air sucked from the opening 5A. The straightening plate 9 has a rectangular plate shape. The current plate 9 is attached to the hood 2 via a hinge 7. The hinge 7 connects the current plate 9 to the hood 2 so that the current plate 9 is rotatable in the up and down direction.

[0024] The current plate 9 has a pair of magnetically attached portions 8. The pair of magnetically attached portions 8 are magnetically attached to the magnetically attached portions 5B at corresponding positions on the inner panel 5. When the magnetically attracted portion 8 is magnetically attracted to the magnetically attracted portion 5B, the current plate 9 is in a closed state. The closed state of the current plate 9 refers to a state in which the current plate 9 is in a position P1 indicated by a solid line in FIG. When the magnetic attraction of the magnetic part 8 to the magnetically attracted part 5B is released, the current plate 9 is in an open state. The open state of the current plate 9 refers to a state in which the current plate 9 is in a position P2 indicated by a dotted line in FIG.

[0025] The ventilation unit 10 draws in the air from the room in which the range hood 1 is installed through the opening 5A by the airflow generated by the ventilation fan 4. At that time, the air passes through the filter 6, and oil, dust, and other substances contained in the air are collected by the filter 6. The air from the room drawn in through the opening 5A is taken into the air blower box 3, passes through the air blower box 3, and is exhausted from the ventilation port. This ventilates the room.

[0026] The air volume control system 20 has a function of controlling the air volume of the ventilation fan 4. As shown in Fig. 1 and Fig. 2, the air volume control system 20 is provided in the hood 2, for example.

[0027] [Air volume control system] FIG. 3 is a block diagram showing an example of the air volume control system 20. 3, the air volume control system 20 includes a control device 22, a relative humidity sensor 24, and a temperature sensor 25. The control device 22, the relative humidity sensor 24, and the temperature sensor 25 are mounted on a single circuit board and provided in the hood 2, for example. The relative humidity sensor 24 is a sensor for detecting the relative humidity in the room. A detection portion of the relative humidity sensor 24 is exposed on the underside of the hood 2. The relative humidity sensor 24 detects water vapor and the like generated during cooking or the like performed below the ventilation unit 10. The relative humidity sensor 24 is connected to the control device 22. The relative humidity sensor 24 provides the detected output to the control device 22. The temperature sensor 25 is a sensor for detecting the temperature inside the room. A detection portion of the temperature sensor 25 is exposed on the lower surface of the hood 2. The temperature sensor 25 is connected to the control device 22. The temperature sensor 25 provides a detected output to the control device 22. The control device 22 is connected to the motor 4b and is capable of giving control commands to the motor 4b.

[0028] The control device 22 is a type of information processing device such as a computer, etc. The control device 22 includes a processing unit 26 and a storage unit 28. The processing unit 26 is, for example, any of various processors suitable for computer control, such as a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), or a field programmable gate array (FPGA).

[0029] The storage unit 28 is, for example, a flash memory, a hard disk, a ROM (Read Only Memory), a RAM (Random Access Memory), or the like. The storage unit 28 stores computer programs and necessary information to be executed by the processing unit 26. The processing unit 26 executes computer programs stored in a computer-readable non-transitory recording medium such as the storage unit 28, thereby realizing various processing functions possessed by the processing unit 26.

[0030] The processing unit 26 has a function of acquiring the detected humidity DH based on the output of the relative humidity sensor 24. The detected humidity DH is a relative humidity obtained based on the output of the relative humidity sensor 24. The processing unit 26 also has a function of acquiring the temperature based on the output of the temperature sensor 25. The processing unit 26 also has a function of giving a control command to the motor 4b to control the rotation speed of the motor 4b. The processing unit 26 can control the volume of the airflow generated by the ventilation fan 4 by controlling the rotation speed of the motor 4b.

[0031] Furthermore, the processing unit 26 has the function of executing a control process 26a and an update process 26b. The control process 26a is a process for controlling the airflow rate (the rotation speed of the motor 4b) based on the detected humidity DH and the reference value RH. The reference value RH is a reference value for controlling the airflow rate. The reference value RH is a value to be compared with the detected humidity DH (relative humidity). The update process 26b is a process for updating the reference value RH so that the difference between the detected humidity DH and the reference value RH becomes smaller. More specifically, the update process 26b is a process of repeatedly performing either a subtraction process or an addition process on the reference value RH. The subtraction process and the addition process will be described later.

[0032] [Regarding update and control processes] FIG. 4 is a flowchart showing an example of the update process performed by the processing unit 26.

[0033] As shown in Fig. 4, the processing unit 26 first sets the reference value RH to 65% (step S1 in Fig. 4). Here, the initial value of the reference value RH is set. Next, the processing unit 26 acquires the detected humidity DH (step S2 in FIG. 4). The processing unit 26 acquires the detected humidity DH based on the current output of the relative humidity sensor 24, and stores it in the storage unit . The processing unit 26 acquires and stores the detected humidity DH every time the update process is repeated. Thus, the detected humidity DH is stored in the storage unit 28 as time-series discrete value data.

[0034] Next, the processing unit 26 determines whether or not the reference value RH is less than the detected humidity DH (step S3 in FIG. 4). When it is determined that the reference value RH is less than the detected humidity DH, the processing unit 26 proceeds to step S4 in FIG. 4 and performs an addition process (step S4 in FIG. 4). In the addition process (step S4 in FIG. 4), the processing unit 26 obtains a difference ΔH by subtracting the current reference value RH from the current detected humidity DH obtained in step S2, and divides the difference ΔH by 180. Furthermore, the processing unit 26 adds a value obtained by dividing the difference ΔH by 180 to the current reference value RH to update the reference value RH. By performing the addition process, the processing unit 26 obtains the updated reference value RH. In this way, the addition process is a process for obtaining an updated reference value RH by adding a predetermined addition value (in this example, a value obtained by dividing the difference ΔH by 180) to the current reference value RH when the reference value RH is less than the detected humidity DH. The addition value in this embodiment is set to a value according to the difference ΔH.

[0035] Having obtained the updated reference value RH, the processing unit 26 then determines whether or not the updated reference value RH is greater than 65% (step S5 in FIG. 4). If the updated reference value RH is determined to be not greater than 65% (is equal to or less than 65%), the processing unit 26 proceeds to step S7. On the other hand, if the updated reference value RH is determined to be greater than 65%, the processing unit 26 sets the updated reference value RH to 65 (step S6 in FIG. 4) and proceeds to step S7. That is, when the updated reference value RH reaches 65% (a predetermined upper limit), the processing unit 26 performs processing to set the updated reference value RH to the upper limit of 65%. In this case, the reference value RH can be prevented from rising more than necessary. If water vapor is generated by cooking or the like and detected, the detected humidity DH will usually be greater than 65%. Therefore, when the detected humidity DH rises due to cooking or the like, the difference ΔH can be appropriately secured, and the airflow control can be made to respond appropriately to the rise in the detected humidity DH.

[0036] 4, in step S7, the processing unit 26 determines whether or not the first interval has elapsed. The first interval is a period set in advance, and is a period for adjusting the timing at which the next process is executed. The processing unit 26 repeats step S7 in FIG. 4 until it determines that the first interval has elapsed. If it is determined that the first interval has elapsed, the processing unit 26 returns to step S2 in FIG.

[0037] Here, the first interval is set to a period in which the period from the immediately preceding addition process to the next process (subtraction process or addition process) is approximately one minute. For example, when the reference value RH is very small with respect to the detected humidity DH, the processing unit 26 repeatedly executes the addition process. At this time, the addition process is repeated approximately every minute.

[0038] In step S3 in FIG. 4, when it is determined that the reference value RH is not less than the detected humidity DH, the processing unit 26 proceeds to step S20 in FIG. 4 and determines whether or not the reference value RH is greater than the detected humidity DH. When it is determined that the reference value RH is not greater than the detected humidity DH (the reference value RH and the detected humidity DH are the same), the processing unit 26 returns to step S2 in Fig. 4. In other words, when the reference value RH and the detected humidity DH are the same, the subtraction process and the addition process are not performed.

[0039] In step S20 in FIG. 4, when it is determined that the reference value RH is greater than the detected humidity DH, the processing unit 26 proceeds to step S8 in FIG. 4 and performs a subtraction process (step S8 in FIG. 4). In the subtraction process (step S8 in FIG. 4), the processing unit 26 subtracts 0.05% from the current reference value RH to update the reference value RH. By performing the subtraction process, the processing unit 26 obtains the updated reference value RH. In this way, the subtraction process is a process in which, when the reference value RH is greater than the detected humidity, a predetermined subtraction value (0.05% in this example) is subtracted from the current reference value RH to obtain an updated reference value RH. The subtraction value in this embodiment is a constant.

[0040] Having obtained the updated reference value RH, the processing unit 26 then determines whether or not the updated reference value RH is smaller than 46% (step S9 in FIG. 4). When it is determined that the updated reference value RH is not smaller than 46% (is equal to or greater than 46%), the processing unit 26 proceeds to step S10.

[0041] 4, in step S10, the processing unit 26 determines whether or not the second interval has elapsed. The second interval is a period set in advance, and is a period for adjusting the timing at which the next process is executed. The processing unit 26 repeats step S10 in FIG. 4 until it determines that the second interval has elapsed. If it is determined that the second interval has elapsed, the processing unit 26 returns to step S2 in FIG.

[0042] Here, the second interval is set to a period in which the period from the immediately preceding subtraction process to the next process (subtraction process or addition process) is approximately 0.5 seconds. For example, when the reference value RH is very large relative to the detected humidity DH, the processing unit 26 repeatedly executes the subtraction process. At this time, the subtraction process is repeated approximately every 0.5 seconds. In this way, the second interval is set to a period shorter than the first interval, or in other words, the first interval is set to a period longer than the second interval.

[0043] In step S9 in FIG. 4, when it is determined that the updated reference value RH is smaller than 46%, the processing unit 26 sets the updated reference value RH to 46% (step S11 in FIG. 4), and proceeds to step S12. That is, when the updated reference value RH reaches 46% (a predetermined lower limit), the processing unit 26 performs processing to set the updated reference value RH to the lower limit of 46%. This makes it possible to prevent the reference value RH from decreasing more than necessary.

[0044] 4, in step S12, the processing unit 26 determines whether or not the third interval has elapsed. The third interval is a period set in advance, and is a period for adjusting the timing at which the next process is executed. The processing unit 26 repeats step S12 in FIG. 4 until it determines that the third interval has elapsed. If it is determined that the third interval has elapsed, the processing unit 26 returns to step S2 in FIG.

[0045] The third interval (predetermined period) is set to a period in which the period from the immediately preceding subtraction process to the next process (subtraction process or addition process) is approximately 40 minutes. Therefore, when the processing unit 26 repeatedly executes the subtraction process and the reference value RH becomes smaller than 46%, the processing unit 26 sets the reference value RH to 46% and maintains the state in which neither the addition process nor the subtraction process is executed for about 40 minutes.

[0046] That is, the processing unit 26 performs processing to restrict the execution of the addition processing and the subtraction processing until 40 minutes (a predetermined period) have elapsed since the updated reference value RH was set to 46%, which is the lower limit value.

[0047] When the approximately 40 minutes determined by the third interval has elapsed, the processing unit 26 returns to step S2 in FIG. 4 and executes the subtraction process or the addition process. As described above, the processor 26 executes the subtraction process when the reference value RH is greater than the detected humidity DH, and executes the addition process when the reference value RH is equal to or less than the detected humidity DH. This updates the reference value RH so that the difference ΔH becomes smaller.

[0048] FIG. 5 is a flowchart showing an example of the control process performed by the processing unit 26. The processor 26 controls the airflow (the rotation speed of the motor 4b) to one of three levels: "strong," "medium," or "weak," depending on the difference ΔH (the value obtained by subtracting the current reference value RH from the current detected humidity DH). When the airflow is "strong," the rotation speed of the motor 4b is the fastest and the airflow is the largest. When the airflow is "weak," the rotation speed of the motor 4b is the slowest and the airflow is the smallest.

[0049] As shown in FIG. 5, the processing unit 26 determines whether or not the current difference ΔH is equal to or greater than 4% (step S21 in FIG. 5). When it is determined in step S21 in FIG. 5 that the difference ΔH is not 4% or more (is less than 4%), the processor 26 controls the motor 4b so that the airflow rate becomes "weak" (step S22), and the process returns to step S21.

[0050] In step S21 in FIG. 5, when it is determined that the difference ΔH is 4% or more, the processing unit 26 determines whether or not the difference ΔH is 16% or more (step S23 in FIG. 5).

[0051] When it is determined in step S23 in FIG. 5 that the difference ΔH is not 16% or more (is less than 16%), the processor 26 controls the motor 4b so that the airflow rate becomes "medium" (step S24), and the process returns to step S21. When it is determined in step S23 in FIG. 5 that the difference ΔH is equal to or greater than 16%, the processing unit 26 controls the motor 4b so that the airflow rate becomes "high" (step S25), and the process returns to step S21. In this way, the processor 26 controls the air volume (the rotation speed of the motor 4b) based on the difference ΔH.

[0052] According to the above configuration, the reference value RH is updated so that the difference ΔH becomes smaller, so that the reference value RH can be changed to follow the detected humidity DH which changes from moment to moment. Therefore, by adjusting the update rate of the reference value RH and the addition and subtraction values ​​so that it cannot follow humidity changes due to cooking operations, etc., the reference value RH, which is the basis for controlling the air volume, can be made to follow the stable humidity that changes depending on the season, weather, etc., and the difference ΔH can be increased to accommodate a sudden increase in humidity due to operations, etc. As a result, the air volume can be appropriately controlled regardless of the season or weather.

[0053] In addition, in this embodiment, the first interval (step S7 in FIG. 4) provided after the addition process (step S4 in FIG. 4) is longer than the second interval (step S10 in FIG. 4) provided after the subtraction process (step S8 in FIG. 4), so the repetition interval when the addition process is repeated is longer than the repetition interval when the subtraction process is repeated. This makes it possible to make the change in the difference ΔH when the addition process is repeated more gradual than the change in the difference ΔH when the subtraction process is repeated. In other words, the ability of the reference value RH to follow the detected humidity DH when the detected humidity DH decreases can be made higher than the ability of the reference value RH to follow the detected humidity DH when the detected humidity DH increases. This allows the difference ΔH when the detected humidity DH increases to be relatively larger than the difference ΔH when the detected humidity DH decreases, and allows a steep increase in the detected humidity DH to be effectively reflected in the difference ΔH. As a result, the air volume can be more appropriately controlled in response to a steep increase in the detected humidity DH.

[0054] Furthermore, in this embodiment, the processing unit 26 performs processing to limit the execution of the addition processing and subtraction processing until 40 minutes have elapsed since the updated reference value RH was set to 46%, which is the lower limit value. As a result, when the addition process is executed after a predetermined period of time has elapsed, the reference value RH has dropped sufficiently, so that the response of the airflow control to the rise in the detected humidity DH can be made quick.

[0055] [About verification testing] Next, a verification test carried out on this embodiment will be described. In the following, a test result will be described in which the change in the reference value RH was confirmed when the detected humidity DH (relative humidity) rose sharply due to cooking or the like after the subtraction process was repeated.

[0056] Fig. 6 is a graph showing an example of changes in the detected humidity DH and the reference value RH, which also shows airflow control. 6, the upper graph shows an example of changes in the detected humidity DH and the reference value RH, while the lower graph shows airflow corresponding to the changes in the detected humidity DH and the reference value RH shown in the upper graph. In the upper part of Fig. 6, the vertical axis represents relative humidity and the horizontal axis represents time. In Fig. 6, a line DL represents a change in the detected humidity DH. A line RL represents a change in the reference value RH.

[0057] At time t0 in FIG. 6, the detected humidity DH is 46% or more, and the detected humidity DH gradually decreases from time t0 to time t1. Therefore, the reference value RH becomes larger than the detected humidity DH, and the processing unit 26 repeatedly executes the subtraction process accordingly. As a result, the reference value RH is updated so that the difference ΔH becomes smaller. Therefore, the reference value RH decreases from time t0 to time t1 so as to follow the detected humidity DH. Note that the slope of the reference value RH (diagram RL) at this time is approximately the same as the slope of the detected humidity DH (diagram DL).

[0058] 6, at time t1, the reference value RH is 46%. Therefore, after time t1, the processing unit 26 sets the reference value RH to "46" and maintains a state in which neither addition processing nor subtraction processing is performed for about 40 minutes. In FIG. 6, time t4 is 40 minutes after time t1. Between time t1 and time t4, the detected humidity DH starts to rise from a decrease. At this time, the detected humidity DH rises steeply. At time t4, the detected humidity DH exceeds 65%. Therefore, at time t4, the reference value RH is smaller than the detected humidity DH. Therefore, after time t4, the processing unit 26 repeatedly executes the addition process. As a result, the reference value RH is updated so that the difference ΔH becomes smaller. Note that the slope of the reference value RH (diagram RL) at this time is smaller than the slope of the detected humidity DH (diagram DL). In other words, the reference value RH cannot sufficiently follow the detected humidity DH.

[0059] 6, at time t6, the reference value RH is 65%. Therefore, the processing unit 26 repeatedly executes the addition process after time t6, but the reference value RH is maintained at 65%, which is the upper limit value. Thereafter, the detected humidity DH starts to decrease and reaches 65% at time t8. The detected humidity DH continues to decrease after time t8. In this case, the reference value RH exceeds the detected humidity DH after time t8. Therefore, after time t8, the processing unit 26 repeatedly executes the subtraction process. As a result, the reference value RH decreases so as to follow the detected humidity DH.

[0060] In FIG. 6, it is assumed that the difference ΔH1 at time t2 is 4%, the difference ΔH2 at time t3 and the difference ΔH3 at time t5 are 16%, and the difference ΔH4 at time t7 is 4%. In this case, the difference ΔH between time t0 and time t2 is less than 4%. Therefore, the processor 26 controls the motor 4b so that the airflow rate between time t0 and time t2 is "weak." Furthermore, the difference ΔH is equal to or greater than 4% and less than 16% between time t2 and time t3. Therefore, the processing unit 26 controls the motor 4b so that the air volume is "medium" between time t2 and time t3.

[0061] Between time t3 and time t5, the difference ΔH is equal to or greater than 16%. Therefore, the processing unit 26 controls the motor 4b so that the airflow rate between time t3 and time t5 is "strong." Between time t5 and time t7, the difference ΔH is equal to or greater than 4% and less than 16%. Therefore, the processor 26 controls the motor 4b so that the air volume between time t2 and time t3 is "medium." After time t7, the difference ΔH becomes less than 4%. Therefore, the processor 26 controls the motor 4b so that the airflow rate becomes "weak" after time t7.

[0062] As described above, from the test results shown in Figure 6, it is clear that the reference value RH can be changed to follow the detected humidity DH, which changes from moment to moment. This makes it clear that the air volume can be appropriately controlled regardless of the season or weather.

[0063] In addition, from the test results shown in FIG. 6, it is clear that the reference value RH follows the detected humidity DH more accurately when the detected humidity DH decreases than when the detected humidity DH increases. This makes it possible to make the difference ΔH larger when the detected humidity DH increases than when the detected humidity DH decreases, and it is found that a steep increase in the detected humidity DH can be effectively reflected in the difference ΔH. From this result, it is clear that the air volume can be more appropriately controlled in response to a steep increase in the detected humidity DH.

[0064] Furthermore, in this embodiment, a state in which neither addition processing nor subtraction processing is performed is maintained for 40 minutes after the lower limit value is reached in the subtraction processing, so that a steep increase in the detected humidity DH can be more effectively reflected in the difference ΔH.

[0065] 〔others〕 It should be noted that the embodiments disclosed herein are illustrative in all respects and are not restrictive. For example, in the above embodiment, the added value in the addition process is set to a value corresponding to the difference ΔH, but the added value in the addition process may be a constant. In the above embodiment, the subtraction value in the subtraction process is a constant, but the subtraction value in the subtraction process may be a variable, such as a value according to the difference ΔH.

[0066] In the above embodiment, the detected humidity DH indicating the relative humidity is obtained by the relative humidity sensor 24 to control the airflow rate of the ventilation fan 4, but the absolute humidity may be used instead of the relative humidity. In this case, the airflow rate can be controlled in the same manner as in the above embodiment. When the absolute humidity is used, the processing unit 26 obtains the absolute humidity using the output of the temperature sensor 25 and the output of the relative humidity sensor 24.

[0067] The scope of the present invention is defined by the claims, not by the meaning described above, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0068] 1. Range hood 2. Food 3. Blower box 4. Ventilation fan 4a Fan body 4b Motor 5 Inner Panel 5A opening 5B Magnetized part 6 Filters 7 Hinge 8 Magnetized part 9 Rectifier plate 10 Ventilation unit 20 Airflow control system 22 Control device 24 Relative Humidity Sensor 25 Temperature Sensor 26 Processing section 26a Control Processing 26b Update process 28 Memory section P1 position P2 position

Claims

1. A humidity sensor for detecting indoor humidity; A control device for controlling the air volume of a ventilation fan that ventilates the room, The control device includes: a control process for controlling the air volume based on a difference between a detected humidity obtained based on an output of the humidity sensor and a reference value; an update process for updating the reference value so as to reduce the difference; Airflow control system.

2. The update process includes: a subtraction process for obtaining an updated reference value by subtracting a predetermined subtraction value from the reference value when the reference value is greater than the detected humidity, and an addition process for obtaining an updated reference value by adding a predetermined addition value to the reference value when the reference value is equal to or less than the detected humidity, A first interval provided after the addition process is longer than a second interval provided after the subtraction process. The airflow control system according to claim 1 .

3. The update process further includes a process of setting the updated reference value to a predetermined lower limit value when the updated reference value reaches the lower limit value. The airflow control system according to claim 2 .

4. The update process further includes a process of restricting execution of the addition process and the subtraction process until a predetermined period of time has elapsed since the updated reference value is set to the lower limit value. The airflow control system according to claim 3 .

5. The update process further includes a process of setting the updated reference value to a predetermined upper limit value when the updated reference value reaches the upper limit value. The airflow control system according to claim 2 .

6. A ventilation fan to ventilate the room, a humidity sensor for detecting the humidity in the room; A control device for controlling the air volume of the ventilation fan, The control device includes: a control process for controlling the air volume based on a difference between a detected humidity obtained based on an output of the humidity sensor and a reference value; an update process for updating the reference value so as to reduce the difference; Range hood.

7. A control device for controlling the air volume of a ventilation fan that ventilates a room, a control process for controlling the air volume based on a difference between a detected humidity obtained based on an output of a humidity sensor that detects the humidity in the room and a reference value; an update process for updating the reference value so as to reduce the difference; Control device.

8. A computer program for causing a computer to execute a process for controlling an air volume of a ventilation fan that ventilates a room, The computer includes: controlling the air volume based on a difference between a detected humidity obtained based on an output of a humidity sensor that detects the humidity in the room and a reference value; updating the reference value so that the difference becomes smaller.

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