Virus reduction method and system

Abstract

To provide a method for reducing viruses that can be expected to be effective in combating infectious viruses without worsening the indoor environment. [Solution] A virus reduction method. This reduction method includes a step of measuring the relative humidity of a space 5, and a ventilation step of replacing and ventilating the air Ai in the space 5 by operating a fan 16. The ventilation step includes a first ventilation step in which the airflow rate of the fan 16 is increased as the relative humidity decreases.

Description

[Technical Field]

[0001] The present invention relates to a method and system for reducing viruses. [Background technology]

[0002] The following Patent Document 1 describes a mitigation system for a house. This mitigation system is equipped with an outside air intake that is installed in the foundation and takes in outdoor air into the underfloor space, and an air supply means that supplies air from the underfloor space to the above-floor space. The air supply means is also equipped with a fan. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-187509 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, sufficient indoor humidification and / or ventilation is proposed as a countermeasure against infectious viruses in buildings such as homes and facilities.

[0005] The former measure inactivates infectious viruses by increasing the relative humidity in the atmosphere. However, if excessive humidification is carried out in the hope of achieving this effect, there is a risk of mold growing indoors.

[0006] The latter measure reduces the risks of the former, but constantly running air purifiers or ventilation fans at high airflow rates can lead to other problems that worsen the indoor environment, such as increased noise.

[0007] The present invention was devised in consideration of the above-mentioned circumstances, and its main purpose is to provide a virus reduction method that can be expected to be effective in preventing infectious viruses without worsening the indoor environment. [Means for solving the problem]

[0008] The present invention is a method for reducing viruses floating in a space, comprising: a step of measuring the relative humidity of the space; and a ventilation step of replacing and ventilating the air in the space by operating a fan, wherein the ventilation step includes a first ventilation step of increasing the airflow rate of the fan as the relative humidity becomes lower. [Effects of the Invention]

[0009] By adopting the above steps, the virus reduction method of the present invention can be expected to be effective in preventing infectious viruses without worsening the indoor environment. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view conceptually showing an example of a house. [Figure 2] FIG. 2 is a conceptual diagram illustrating an example of the configuration of a control device. [Figure 3] 1 is a flowchart showing an example of a processing procedure for a virus reduction method; [Figure 4] 10 is a flowchart showing an example of a processing procedure of a ventilation step. [Figure 5] FIG. 10 is a diagram showing an example of fan airflow rates (notches) designated for each range of relative humidity in a space. [Figure 6] 10 is a flowchart showing an example of a processing procedure of a relationship acquisition step (relationship acquisition method). [Figure 7] 1 is a graph showing an example of a first relationship. [Figure 8] 10 is a graph showing an example of a second relationship. [Figure 9] 10 is a flowchart showing an example of a processing procedure of a first ventilation step according to another embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view conceptually illustrating an example of a house according to another embodiment of the present invention. [Figure 11]10 is a flowchart showing an example of a processing procedure of a virus reduction method according to another embodiment of the present invention. [Figure 12] 10 is a flowchart showing an example of a procedure for a cleaning step. [Figure 13] 10 is a flowchart showing an example of a processing procedure of a first cleaning step according to another embodiment of the present invention. [Figure 14] FIG. 10 is a cross-sectional view conceptually showing an example of a house 1 according to still another embodiment of the present invention. [Figure 15] 10 is a flowchart illustrating an example of a processing procedure of a reduction method. [Figure 16] 10 is a graph showing an example of a first relationship according to another embodiment of the present invention. [Figure 17] 10 is a graph showing an example of a second relationship according to another embodiment of the present invention. [Figure 18] FIG. 10 is a cross-sectional view conceptually showing an example of a house according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be understood that the drawings include exaggerated representations and representations that differ from the dimensional ratios of actual structures in order to facilitate understanding of the contents of the invention. Furthermore, identical or common elements are designated by the same reference numerals throughout the embodiments, and redundant explanations will be omitted. Furthermore, the specific configurations shown in the embodiments and drawings are for the purpose of understanding the contents of the present invention, and the present invention is not limited to the specific configurations shown in the drawings.

[0012] A virus reduction system (hereinafter referred to as a "reduction system") is designed to reduce viruses (infectious diseases) floating in space. Such a reduction system can reduce the risk of virus infection within a space.

[0013] In this embodiment, the virus-reducing space is provided in a home, but the present invention is not limited to this. For example, the virus-reducing space may be provided in a building such as a building or facility. Furthermore, the virus may include influenza viruses, which tend to be prevalent every year, and novel coronaviruses, which tend to be prevalent regardless of the season. This can reduce the risk of infection with these viruses.

[0014] [Overall structure of the house] 1 is a cross-sectional view conceptually illustrating an example of a house 1. The house 1 of this embodiment is configured as, for example, an industrialized house with excellent thermal insulation performance. However, the house 1 is not limited to an industrialized house.

[0015] The house 1 of this embodiment is provided with an above-floor space 2 and an under-floor space 3 provided below the above-floor space 2. In this embodiment, the space 5 in which viruses are reduced by the reduction system 4 is illustrated as the above-floor space 2 (living room 6), but this is not particularly limited, and may be, for example, the under-floor space 3, or both the above-floor space 2 and the under-floor space 3.

[0016] [Floor space] The above-floor space 2 is provided above the under-floor space 3 via a floor 7. In this embodiment, the above-floor space 2 is partitioned by the floor 7, a ceiling 8, an exterior wall 9, and a partition wall (not shown). A living room 6 is provided in the above-floor space 2.

[0017] [Underfloor space] The underfloor space 3 is partitioned by the floor 7, a foundation 11, and a dirt floor 12. In this embodiment, the foundation 11 is provided with a heat insulating material 14. The heat insulating material 14 is intended to reduce temperature changes in the air in the underfloor space 3 (hereinafter, sometimes simply referred to as "underfloor air"). For example, polystyrene foam or the like can be used as the heat insulating material 14.

[0018] [Virus reduction system (first embodiment)] The reduction system 4 of this embodiment includes a humidity sensor 15, a fan (hereinafter sometimes referred to as a "first fan") 16, and a control device 17. In this specification, a "fan" is a machine for compressing and sending air. Therefore, the first fan 16 and a second fan (described later) are not particularly limited as long as they are capable of compressing and sending air.

[0019] The reduction system 4 of this embodiment further includes an air conditioner 19. By operating this air conditioner 19, the reduction system 4 can air-condition the space 5 (above-floor space 2) while reducing viruses. Note that the reduction system 4 is not limited to an embodiment in which the air conditioner 19 is included, and the air conditioner 19 may be omitted.

[0020] [Humidity sensor] Humidity sensor 15 is used to measure the relative humidity of space 5. There are no particular limitations on the humidity sensor 15 as long as it is capable of measuring relative humidity, and for example, a known sensor may be used. Note that humidity sensor 15 may also be configured as a temperature / humidity sensor that can measure not only relative humidity but also temperature.

[0021] The humidity sensor 15 is disposed in the space 5 to be ventilated (above-floor space 2). This allows the relative humidity of the air in the space 5 (hereinafter sometimes referred to as "space air") Ai to be measured. The measured relative humidity is transmitted to the control device 17.

[0022] [Fan (1st fan)] The fan (hereinafter sometimes referred to as the "first fan") 16 is for pressure-feeding (exhausting) the air (space air) Ai in the space 5 to the outdoors 27 via the exhaust port 26. Note that the first fan 16 of this embodiment is not limited to a mode in which the space air Ai is pressure-feeded to the outdoors 27, and may, for example, be a fan that pressure-feeds (supplies) outside air Ao into the space 5. In this embodiment, the operation of the first fan 16 can be controlled by the control device 17.

[0023] The airflow rate of the first fan 16 is controlled in multiple stages. In this embodiment, the airflow rate of the first fan 16 is controlled in multiple stages based on multiple predetermined notches. The notches include, for example, a strong notch, a weak notch, and a stop notch. Of these notches, the strong notch is set to the largest airflow rate per unit time, and the stop notch is set to the smallest airflow rate (in this example, the ventilation rate is 0.0 times / h). The airflow rate of each notch is set appropriately depending on, for example, the size of the space 5 (in this example, the living room 6), the ventilation rate, etc. An example of converting the airflow rate of each notch into the ventilation rate (times / h) of the space 5 is as follows: Strong notch: 3.5 times / h Weak notch: 0.5 times / h Stop notch: 0.0 times / h

[0024] [Air conditioner] The air conditioner 19 conditions the space air Ai. The air conditioner 19 of this embodiment is configured, for example, as a typical split-type air conditioner for home use, and includes an indoor unit 19a and an outdoor unit (not shown) as a set. In this embodiment, the operation of the air conditioner 19 can be controlled by the control device 17.

[0025] [Space ventilation] In the reduction system 4 of this embodiment, by operating the first fan 16, the space air Ai is pressurized (discharged) to the outdoors 27 via the exhaust port 26. This discharge of the space air Ai creates a negative pressure in the space 5, and outside air Ao is supplied into the space 5 from the air intake port 28. In this way, in the reduction system 4, the space air Ai is replaced by the supply of outside air Ao and the discharge of the space air Ai, and the space 5 (above-floor space 2) can be ventilated.

[0026] In the reduction system 4 of this embodiment, the space air Ai is replaced and ventilated, so that particles (including viruses) floating in the space air Ai can be discharged outside the space 5 (outdoors 27). As a result, in the reduction system 4 of this embodiment, the particles floating in the space air Ai are reduced, making it possible to reduce viruses.

[0027] [Control device] Fig. 2 is a conceptual diagram showing an example of the configuration of the control device 17. The control device 17 is configured by a computer and is installed, for example, on the partition wall shown in Fig. 1. The control device 17 is configured to include, for example, a calculation unit (CPU) 31, a storage device 32 for storing processing procedures and the like, and a working memory 33 for reading the processing procedures and the like from the storage device 32. An input device 34 and an output device 35 are connected to the control device 17 (calculation unit 31).

[0028] [Input / Output Devices] The input device 34 of this embodiment is configured, for example, by operation buttons, a touch panel, or the like (not shown) provided on the housing of the control device 17 shown in FIG. 1. By using such an input device 34, for example, input data (signals) by a user (resident), etc. can be transmitted to the control device 17. Furthermore, the output device 35 of this embodiment is configured, for example, as a display (not shown) provided on the housing of the control device 17 shown in FIG. 1. The output device 35 can display the operating status of the reduction system 4, etc.

[0029] [Arithmetic device] The arithmetic unit 31 of this embodiment is configured by, for example, a CPU (Central Processing Unit).

[0030] The arithmetic device 31 of this embodiment is communicably connected to the humidity sensor 15. This allows the arithmetic device 31 to grasp the measurement result of the relative humidity of the space air Ai.

[0031] The arithmetic device 31 of this embodiment is communicatively connected to the first fan 16. This allows the arithmetic device 31 to grasp the operating status of the first fan 16. This operating status includes, for example, the air volume (notch) and the rotation speed. Furthermore, the operation of the first fan 16 (including, for example, starting and stopping the operation and switching the air volume (notch)) can be controlled by the arithmetic device 31.

[0032] The arithmetic device 31 of this embodiment is communicatively connected to the air conditioner 19. This allows the arithmetic device 31 to control the operation of the air conditioner 19 (for example, starting and stopping operation, etc.).

[0033] [Storage device] The storage device 32 of this embodiment is, for example, a non-volatile information storage device. The storage device 32 includes a data section 36 and a program section 37.

[0034] The data unit 36 ​​in this embodiment is for storing data necessary for virus reduction by the reduction system 4, calculation results (calculation data) by the arithmetic device 31, etc. These data are used to execute the processing procedures of the virus reduction method (hereinafter sometimes referred to as the "reduction method") and the relationship acquisition method described below.

[0035] The data unit 36 ​​of this embodiment includes a relative humidity storage unit 36a, a condition storage unit 36b, an infectivity titer decay storage unit 36c, an infectivity titer ventilation rate storage unit 36d, and a relationship storage unit 36e. The data unit 36 ​​may further include a storage unit for storing other information. The data stored therein will be explained in the respective steps of the reduction method and the relationship acquisition method described below.

[0036] [Program section] The program unit 37 is a program (computer program) for causing the arithmetic device 31 (control device 17) to execute the processing procedures of the reduction method and the relationship acquisition method described below. When the program unit (program) 37 is executed by the arithmetic device 31, the control device 17 can function as a specific means.

[0037] The program unit 37 of this embodiment includes a humidity measurement unit 37a, a humidity determination unit 37b, a ventilation unit 37c, a cleaning unit 37d, a termination determination unit 37e, a termination unit 37f, and a relationship acquisition unit 37g. The ventilation unit 37c of this embodiment includes a first ventilation unit 39 and a second ventilation unit 40. The cleaning unit 37d of this embodiment includes a first cleaning unit 44 and a second cleaning unit 45. The relationship acquisition unit 37g of this embodiment includes a first identification unit 41, a second identification unit 42, and a third identification unit 43. Note that the program unit 37 is not limited to this embodiment, and other programs may be included, or some of these programs may be omitted. The functions of these programs will be described in the respective steps of the reduction method and relationship acquisition method described below.

[0038] [Findings of the inventors] Incidentally, as a countermeasure against infectious viruses in space 5 shown in FIG. 1, for example, sufficient humidification and / or ventilation of space 5 is considered effective. For example, by humidifying space 5, the relative humidity in the atmosphere of space 5 is increased, which can inactivate viruses. However, if excessive humidification is performed in anticipation of such an effect, there is a concern that mold may grow in space 5. On the other hand, while ventilating space 5 reduces the above-mentioned risk, constantly operating first fan 16 and the like at a high airflow rate may cause other indoor environmental degradation, such as noise.

[0039] As a result of extensive research, the inventors have found that increasing the airflow rate of the fan (first fan) 16 tends to promote the attenuation of viruses associated with the replacement of the space air Ai and the inactivation of viruses associated with the increase in the airflow velocity of the space air Ai. They have also found that the lower the relative humidity of the space 5, the greater the airflow rate of the first fan 16, thereby enabling the infectivity (infection risk) of infectious viruses (hereinafter sometimes referred to as "viruses") to be maintained low without humidifying the space 5.

[0040] [Virus reduction method (first embodiment)] Based on the above findings, the reduction method (reduction system 4) of this embodiment controls the airflow rate (notch) of the fan (first fan) 16 according to the relative humidity of the space 5. This makes it possible to maintain low viral infectivity without excessively humidifying the space 5 or constantly operating the first fan 16 at a high airflow rate. Therefore, the reduction method (reduction system 4) of this embodiment can be expected to be effective in preventing infectious viruses without worsening the indoor environment, such as by causing mold growth or noise.

[0041] In this embodiment, the processing of each step of the virus reduction method can be performed by executing a program unit 37 included in the control device 17 of the reduction system 4 shown in Fig. 2 by the arithmetic device 31. Fig. 3 is a flowchart showing an example of the processing procedure of the virus reduction method.

[0042] [Measure the relative humidity of the space] In the reduction method of this embodiment, first, the relative humidity in the space 5 shown in Fig. 1 is measured (step S1). To measure the relative humidity, a humidity sensor 15 provided in the space 5 is used.

[0043] In step S1 of this embodiment, a humidity measurement unit 37a included in the program unit 37 shown in FIG. 2 is loaded into the working memory 33. The humidity measurement unit 37a is a program for measuring the relative humidity of the space 5 (shown in FIG. 1). When the humidity measurement unit 37a is executed by the arithmetic device 31, the control device 17 can function as a means for measuring the relative humidity of the space 5.

[0044] In step S1 of this embodiment, the humidity measurement unit 37a (control device 17) acquires the relative humidity of the space 5 measured by the humidity sensor 15 shown in Fig. 1. The acquired relative humidity of the space 5 is input to the relative humidity storage unit 36a shown in Fig. 2.

[0045] [Replacing the air in the space and ventilating it (ventilation process)] Next, in the reduction method of this embodiment, the air (space air) Ai in the space 5 shown in Fig. 1 is replaced and ventilated (ventilation step S2). In the ventilation step S2 of this embodiment, the first fan 16 is operated to replace the space air Ai and ventilate the space 5. Fig. 4 is a flowchart showing an example of the processing procedure of the ventilation step S2.

[0046] [Determine whether the relative humidity in the space is above the threshold] In the ventilation step S2 of this embodiment, first, it is determined whether the relative humidity in the space 5 shown in FIG. 1 is equal to or lower than a predetermined threshold value (step S21).

[0047] In step S21 of this embodiment, the relative humidity of the space 5 inputted to the relative humidity storage unit 36a shown in Fig. 2 and a humidity determination unit 37b included in the program unit 37 are read into the working memory 33. The humidity determination unit 37b is a program for determining whether the relative humidity of the space 5 shown in Fig. 1 is equal to or lower than a threshold value. When the humidity determination unit 37b is executed by the arithmetic unit 31, the control device 17 can function as a means for determining whether the relative humidity is equal to or lower than a threshold value.

[0048] The threshold value is used to determine the infectivity (risk of infection) of a virus in space 5 from the relative humidity of space 5 shown in FIG. 1. This threshold value can be set as appropriate. In general, the lower the relative humidity of space 5, the higher the infectivity of a virus tends to be. For example, in the case of influenza viruses, it is said that the infectivity of the virus increases rapidly when the relative humidity falls below 50% RH. From this perspective, it is preferable to set the threshold value to 45% RH to 65% RH (56% RH in this example).

[0049] If the relative humidity in space 5 is equal to or lower than the threshold value ("Yes" in step S21), it is determined that the infectivity of the virus in space 5 is high. In this case, the first ventilation step S22 is performed. On the other hand, if the relative humidity in space 5 is higher than the threshold value ("No" in step S21), it is determined that the infectivity of the virus in space 5 is low. In this case, the second ventilation step S23 is performed.

[0050] [The lower the relative humidity in the space, the greater the fan's airflow (first ventilation process)] Next, in the ventilation step S2 of this embodiment, the lower the relative humidity in the space 5 shown in FIG. 1, the larger the air volume of the fan (first fan) 16 is set (first ventilation step S22).

[0051] In the first ventilation step S22 of this embodiment, the relative humidity of the space 5 (shown in FIG. 1) input into the relative humidity storage unit 36a shown in FIG. 2 and a first ventilation unit 39 included in the ventilation unit 37c of the program unit 37 are read into the working memory 33. The first ventilation unit 39 is a program for increasing the airflow rate of the first fan 16 as the relative humidity of the space 5 shown in FIG. 1 decreases. Execution of this first ventilation unit 39 by the arithmetic unit 31 causes the control device 17 to function as a means for increasing the airflow rate as the relative humidity decreases.

[0052] In the first ventilation step S22 of this embodiment, when the operation of the first fan 16 shown in Fig. 1 is stopped, the first ventilation unit 39 (control device 17) shown in Fig. 2 starts the operation of the first fan 16. This allows the space air Ai to be replaced, and the space 5 to be ventilated.

[0053] In the first ventilation step S22 of this embodiment, when the operation of the air conditioner 19 is stopped, the first ventilation unit 39 (control device 17) shown in FIG. 2 may perform a step (not shown in the flowchart) of conditioning the space air Ai with the air conditioner 19. In this case, the temperature and air volume of the air conditioner 19 can be set appropriately depending on the indoor environment (temperature, solar radiation, etc.) in the space 5. Note that when air conditioning of the space 5 is not required, the operation of the air conditioner 19 may be stopped.

[0054] As described above, in this embodiment, when it is determined that the infectivity of the virus is high ("Yes" in step S21), the first ventilation step S22 is performed. In the first ventilation step S22 when it is determined that the infectivity is high, the lower the relative humidity of the space 5, the larger the airflow rate of the first fan 16 is (in this example, the first fan 16 is operated at a notch that increases the ventilation rate). This promotes the reduction (attenuation) of viruses associated with the replacement of the space air Ai and the inactivation of viruses associated with the increase in the airflow velocity of the space air Ai, thereby maintaining the infectivity of the virus at a low level.

[0055] The airflow rate of first fan 16 can be set appropriately as long as it can promote the reduction of viruses and maintain the infectivity of the viruses at a low level. For example, it is preferable that the airflow rate of first fan 16 be set so as to provide an air change rate equal to or greater than the required air change rate (0.5 times / h) of space 5.

[0056] On the other hand, in the first ventilation step S22 of this embodiment, the higher the relative humidity of the space 5 (i.e., the closer the relative humidity is to or below the threshold value and the closer the relative humidity is to the threshold value), the smaller the airflow rate (notch) of the first fan 16 is kept. In this case, for example, the airflow rate (for example, a weak notch) of the first fan 16 may be set so as to achieve a ventilation rate close to the ventilation rate (0.5 times / h) required for the space 5. This can prevent the indoor environment from being deteriorated due to noise generated when the first fan 16 is operating. Furthermore, an increase in power consumption of the first fan 16 can be prevented.

[0057] As described above, in the first ventilation step S22 (first ventilation section 39 shown in FIG. 2) of this embodiment, the lower the relative humidity of space 5, the larger the airflow rate (notch) of first fan 16, which can promote the reduction (attenuation) and inactivation of viruses. On the other hand, in the first ventilation step S22 of this embodiment, the higher the relative humidity of space 5, the smaller the airflow rate (notch) of first fan 16, which can reduce noise and power consumption during operation of first fan 16. As a result, the reduction method (reduction system 4) of this embodiment can be expected to be effective in preventing infectious diseases without worsening the indoor environment.

[0058] If the airflow rate of the first fan 16 is uniformly increased (for example, set to a strong notch) as the relative humidity of the space 5 decreases, viruses are reduced (infectivity is reduced), but noise and power consumption during operation of the first fan 16 increase. As described above, there is a trade-off between virus reduction (reducing virus infectivity) and reduction in noise and power consumption of the first fan 16. Therefore, in the first ventilation step S22 (first ventilation section 39 shown in FIG. 2 ), it is preferable to increase the airflow rate (notch) of the first fan 16 in stages as the relative humidity of the space 5 decreases. Similarly, it is preferable to decrease the airflow rate of the first fan 16 in stages as the relative humidity of the space 5 increases. This makes it possible to set the airflow rate of the first fan 16 in a way that achieves a good balance between the trade-off between "virus reduction (reducing infectivity)" and "reducing noise and power consumption."

[0059] The airflow rate of the first fan 16 can be set to increase (decrease) in stages as appropriate. For example, an airflow rate (notch) may be specified for each predetermined range of relative humidity so that the airflow rate of the first fan 16 increases in stages as the relative humidity of the space 5 decreases. This allows the airflow rate of the first fan 16 to be uniquely determined according to the relative humidity. FIG. 5 is a diagram showing an example of the airflow rate (notch) of the first fan 16 specified for each range of relative humidity of the space 5.

[0060] In the first ventilation step S22 of this embodiment (first ventilation section 39 shown in FIG. 2), as shown in FIG. 5, the airflow rate (notch) of the first fan 16 is increased stepwise in response to a decrease in the relative humidity of the space 5. As a result, in the first ventilation step S22 of this embodiment, the airflow rate (notch) of the first fan 16 can be set to achieve a good balance between reducing viruses (reducing infectivity) and reducing noise and power consumption. Therefore, the reduction method (reduction system 4) of this embodiment can be expected to be more effective in preventing infectious viruses without worsening the indoor environment.

[0061] [Set the fan airflow rate based on the required ventilation rate (second ventilation process)] Next, in the ventilation step S2 of this embodiment, as shown in FIGS. 1 and 4, the air volume (notch) of the first fan 16 is set based on the required ventilation rate of the space 5 (second ventilation step S23).

[0062] In the second ventilation step S23 of this embodiment, a second ventilation unit 40 included in the ventilation unit 37c of the program unit 37 shown in Fig. 2 is loaded into the working memory 33. The second ventilation unit 40 is a program for setting the air volume (notch) of the first fan 16 based on the required ventilation rate of the space 5 shown in Fig. 1. When the second ventilation unit 40 is executed by the calculation device 31, the control device 17 can function as a means for setting the air volume (notch) of the first fan 16 based on the required ventilation rate.

[0063] In the second ventilation step S23 of this embodiment, when the operation of the first fan 16 shown in Fig. 1 is stopped, the second ventilation unit 40 (control device 17) shown in Fig. 2 starts the operation of the first fan 16. This allows the space air Ai to be replaced, and the space 5 to be ventilated.

[0064] In the second ventilation step S23 of this embodiment, when the operation of the air conditioner 19 is stopped, the second ventilation unit 40 (control device 17) shown in FIG. 2 may perform a step (not shown in the flowchart) of conditioning the space air Ai with the air conditioner 19. In this case, the temperature and air volume of the air conditioner 19 can be set appropriately depending on the indoor environment (temperature, solar radiation, etc.) in the space 5. Note that when air conditioning of the space 5 is not required, the operation of the air conditioner 19 may be stopped.

[0065] As described above, in this embodiment, when it is determined that the infectivity of the virus is low ("No" in step S21), the second ventilation step S23 is performed. In the second ventilation step S23 when it is determined that the infectivity is low, the airflow rate of the first fan 16 (in this example, a weak notch) is set based on the required ventilation rate of the space 5. This keeps the airflow rate (notch) of the first fan 16 to a necessary minimum, making it possible to effectively reduce the noise and power consumption of the first fan 16 without deteriorating the effectiveness of measures against infectious viruses.

[0066] [Determine whether or not ventilation is stopped] Next, as shown in Fig. 3, in the reduction method of this embodiment, it is determined whether or not an instruction to end ventilation of space 5 has been issued (step S3). In step S3 of this embodiment, a termination determination unit 37e included in program unit 37 shown in Fig. 2 is loaded into working memory 33. This termination determination unit 37e is a program for determining whether or not an instruction to end ventilation of space 5 shown in Fig. 1 has been issued. By executing this termination determination unit 37e by calculation device 31, control device 17 can function as a means for determining whether or not an instruction to end ventilation has been issued.

[0067] The determination of whether or not there is an instruction to terminate is made based on, for example, instruction data input by a user (resident) or the like to the input device 34 (shown in FIG. 2) shown in FIG. 2, or the occurrence of an abnormal termination of an interrupt process or the like.

[0068] In this embodiment, if it is determined that an end instruction has been given ("Yes" in step S3), step S4 is performed to end the ventilation of space 5 shown in Fig. 1. On the other hand, if it is determined that an end instruction has not been given ("No" in step S3), steps S1 to S3 are performed again.

[0069] The reduction method (reduction system 4) of this embodiment appropriately switches between the first ventilation step S22 and the second ventilation step S23 shown in Fig. 4 while determining the infectivity of the virus based on the ever-changing relative humidity of the space 5 from the start to the end of ventilation of the space 5. As a result, the reduction method (reduction system 4) can increase the airflow (notch) of the first fan 16 as the relative humidity decreases (as the infectivity increases), making it possible to expect continuous effectiveness in preventing infectious viruses without worsening the indoor environment.

[0070] [Ventilation ends] Next, in the reduction method of this embodiment, if the determination in step S3 shown in FIG. 3 is affirmative ("Yes" in step S3), the ventilation of space 5 shown in FIG. 1 is terminated (step S4). In step S4 of this embodiment, a termination section 37f included in program section 37 shown in FIG. 2 is loaded into working memory 33. This termination section 37f is a program for terminating ventilation of space 5. Execution of this termination section 37f by calculation device 31 allows control device 17 to function as a means for terminating ventilation of space 5.

[0071] In step S4 of this embodiment, the termination unit 37f (control device 17) shown in FIG. 2 stops the operation of the first fan 16 and the air conditioner 19 shown in FIG. 1. This ends the ventilation and air conditioning of the space 5. Note that the operation of the first fan 16 may continue to ventilate the space 5. In this case, the notch of the first fan 16 is appropriately set based on, for example, the required ventilation rate of the space 5.

[0072] [Virus reduction method (another example of the first embodiment)] In the first ventilation step S22 (first ventilation section 39 shown in FIG. 2) of the embodiments described above, as shown in FIG. 5, attention is focused only on the relative humidity of space 5, and the lower the relative humidity, the larger the airflow rate (notch) of first fan 16 is set, but this is not limiting. For example, the airflow rate (notch) of first fan 16 may be determined based on a previously prepared relationship between the relative humidity, the virus infectivity titer ventilation rate, and the airflow rate (notch) of first fan 16 so that the virus infectivity titer ventilation rate is equal to or greater than a predetermined rate.

[0073] The virus infectivity ventilation rate is a ventilation rate determined based on the decay of airborne viruses over time (decrease in virus infectivity). The virus infectivity ventilation rate can be calculated appropriately, for example, using the following formula (1):

[0074]

number

[0075] The above formula (1) is the Seidel formula described in JIS-A1406 "Indoor Ventilation Volume Measurement Method (Carbon Dioxide Method)" with "CO2 concentration" replaced with "virus infectivity titer." This change is based on the assumption that the decay of CO2 concentration due to ventilation can be considered the same as the decay of virus infectivity titer due to ventilation. Note that, unlike CO2 concentration, this embodiment is premised on the assumption that viruses are not constantly supplied. For this reason, the "CO2 concentration C0 in the supply air" in the Seidel formula is omitted. Furthermore, in this embodiment, instead of calculating the supply air volume Q required for the room volume V as in the Seidel formula, the ventilation rate is calculated based on the decay of the infectivity titer. For this reason, the "supply air volume Q" and "room volume V" in the Seidel formula are omitted in the above formula (1).

[0076] Infectivity titers C1 and C t is the amount of infectious virus. These infectious titers C1 and C t For example, the literature ("Test method for evaluating the removal performance of air purifiers against floating viruses," [online], July 4, 2011, Japan Electrical Manufacturers' Association, [searched July 5, 2024], Internet<URL:https: / / www.jema-net.or.jp / Japanese / ha / kuusei / hyoukashiken / hyouka1.pdf> ) can be measured based on a similar procedure.

[0077] In the above formula (1), the infectious titer C after the elapsed time t from the start of measurement is compared to the infectious titer C1 at the start of measurement. t The smaller the viral infectivity titer ventilation rate F, the larger the viral infectivity titer ventilation rate F. Therefore, as the viral infectivity titer ventilation rate F increases, the amount of infectious virus decreases (i.e., the ratio of the infectivity titer C to the infectivity titer C). t Since the infectiousness of the virus (risk of infection) is reduced, it can be determined that the infectiousness of the virus (risk of infection) is low.

[0078] On the other hand, in the above formula (1), the infectious titer C after the elapsed time t from the start of measurement tThe larger the viral infectivity titer ventilation rate F, the smaller the viral infectivity titer ventilation rate F. Therefore, as the viral infectivity titer ventilation rate F decreases, the amount of infectious virus increases (i.e., the infectivity titer C t Since the number of infected people increases, it can be determined that the virus is highly infectious (risk of infection).

[0079] In this way, the viral infectivity ventilation rate F can be treated as a parameter for identifying the infectivity (infection risk) of a virus.

[0080] As described above, the smaller the viral infectivity titer ventilation rate F, the higher the infectivity of the virus. Therefore, it is preferable to determine the airflow rate (notch) of the first fan 16 so that the viral infectivity titer ventilation rate F is equal to or greater than a predetermined rate. The rate at which the viral infectivity titer ventilation rate F should be satisfied can be set appropriately. According to the U.S. Centers for Disease Control and Prevention (CDC), ventilation at an equivalent ventilation rate of 5 times / h or greater is recommended to reduce the risk of infection (infectivity) of viruses such as influenza. Here, the "equivalent ventilation rate" is calculated based on the ventilation volume that takes into account not only ventilation by air exchange but also methods that have similar effects to ventilation (including the effect of reducing the risk of infection). An example of a "method that has similar effects to ventilation" is a method using an air purifier. For example, if the effect obtained by using an air purifier is equivalent to two ventilations, the equivalent ventilation rate would be calculated by adding the ventilation rate at which the air is actually exchanged to the two ventilations. From this perspective, in this embodiment, the air volume (notch) of the first fan 16 is determined so that the virus infectivity ventilation rate (equivalent ventilation rate) F is 5 times / h or more.

[0081] The infectivity of the virus (virus infectivity ventilation rate F) varies depending on the relative humidity of the space 5 and the airflow rate (notch) of the first fan 16. For this reason, it is preferable to determine the airflow rate (notch) of the first fan 16 based on the relationship between the virus infectivity ventilation rate F, the relative humidity, and the airflow rate (notch) of the first fan 16 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example). To enable such determination of the airflow rate of the first fan 16, it is preferable to include a relationship obtaining step of determining the above relationship prior to the ventilation step S2.

[0082] [Relationship Acquisition Process (Relationship Acquisition Method)] Next, the relationship acquisition step (relationship acquisition method) of this embodiment will be described. In this relationship acquisition step, a relationship among the relative humidity, the virus infectivity titer ventilation rate F, and the airflow rate (notch) of the first fan 16, which is prepared in advance, is acquired.

[0083] As described above, the virus infectivity titer measured based on the procedure described in the above-mentioned document is used to calculate the virus infectivity titer air change rate in this embodiment. For this reason, the relationship between the virus infectivity titer air change rate F, relative humidity, and the airflow rate of first fan 16 is preferably obtained in the test chamber described in the above-mentioned document, rather than in house 1 shown in Fig. 1. Fig. 6 is a flowchart showing an example of the processing procedure of the relationship acquisition step (relationship acquisition method).

[0084] [Identifying the decay of infectivity titer under multiple conditions (Step 1)] In the relationship acquisition step (relationship acquisition method) of this embodiment, first, the decay over time of the infectivity titer of airborne viruses is identified under multiple conditions that associate the airflow (notch) of the first fan 16 with the relative humidity of the air (first step S71).

[0085] The multiple conditions can be set as appropriate as long as the airflow rate (notch) of the first fan 16 is associated with the relative humidity of the air. In this embodiment, the airflow rate is set to the controllable airflow rate (strong notch, weak notch, and off notch) of the first fan 16 shown in FIG. 1. Preferably, multiple relative humidities are prepared for the space 5. In this embodiment, the relative humidities can be set to 25% RH, 50% RH, and 75% RH. By associating these three airflow rates (notches) with the three relative humidities, nine conditions are set. Note that the multiple conditions are not limited to these examples, and some of them may be omitted, or other conditions may be added.

[0086] The decay of the virus infectivity over time is calculated by dividing the virus infectivity C1 at the start of measurement (t=0) by the virus infectivity C1 after the elapsed time t from the start of measurement. t The ratio C1 / C t The elapsed time t is set to 15 to 60 minutes (30 minutes in this example).

[0087] Ratio C1 / C t The larger the value, the higher the infectious titer C of the virus after the elapsed time t. t As the ratio C1 / C becomes smaller, the decay of the infectivity titer over time becomes larger. t The smaller the ratio C1 / C, the smaller the decay of the infectious titer over time. t can be acquired for each of a plurality of types of conditions. The plurality of types of conditions and the elapsed time t are input in advance to the condition storage unit 36b shown in FIG.

[0088] In the first step S71 of this embodiment, first, the multiple types of conditions and elapsed time t input into the condition storage unit 36b shown in FIG. 2 and a first identification unit 41 included in the program unit 37 are loaded into the working memory 33. The first identification unit 41 is a program for identifying the decay over time of the infectivity titer of airborne viruses under multiple types of conditions that associate the airflow rate (notch) of the first fan 16 with the relative humidity of the air. Execution of this first identification unit 41 by the arithmetic device 31 allows the control device 17 to function as a means for identifying the decay of the infectivity titer under multiple types of conditions.

[0089] In the first step S71 of this embodiment, first, one condition (for example, a first condition associating a stop notch with 25% RH) is selected from a plurality of types of conditions (nine types of conditions in this example). Next, in the first step S71, the relative humidity in the test chamber and the air volume (notch) of the fan are set based on the selected first condition. Next, in the test chamber, the infectivity titer C1 at the start of measurement and the infectivity titer C1 after the elapsed time t from the start of measurement are calculated. t Then, based on the measurement results, the decay of the infectious titer (ratio C1 / C t ) is identified.

[0090] Next, in the first step S71 of this embodiment, the attenuation of the infectivity titer (ratio C1 / C t The decay of the infectious titer (ratio C1 / C t ) is input to the infectivity titer attenuation storage unit 36c shown in FIG.

[0091] [Identifying the viral infectivity ventilation rate F under multiple conditions (Step 2)] Next, in the relationship acquisition step (relationship acquisition method) of this embodiment, the virus infectivity ventilation rate F is identified for a plurality of conditions (nine conditions in this example) from the results of the first step S71 (second step S72).

[0092] In the second step S72 of this embodiment, first, the elapsed time t inputted in the condition storage unit 36b shown in FIG. 2 and the infectivity titer decay (ratio C1 / C t ) are loaded into the working memory 33. Furthermore, a second identification unit 42 included in the program unit 37 is loaded into the working memory 33. The second identification unit 42 is a program for identifying the virus infectivity titer air change rate F under a plurality of types of conditions based on the results of the first step S71. When the second identification unit 42 is executed by the arithmetic device 31, the control device 17 can function as a means for identifying the virus infectivity titer air change rate F under a plurality of types of conditions.

[0093] In the second step S72 of this embodiment, the elapsed time t and the decay of the infectivity titer (ratio C1 / C t ) are respectively substituted into the above formula (1). As a result, the virus infectivity titer ventilation rate F is specified for each of the multiple conditions. The specified virus infectivity titer ventilation rate F is input into the infectivity titer ventilation rate memory unit 36d shown in FIG. 2.

[0094] [Identify relationships based on the results of the second step (third step)] Next, in the relationship acquisition step (relationship acquisition method) of this embodiment, the relationship among the relative humidity, the virus infectivity titer ventilation rate, and the air volume (notch) of the first fan 16 is identified based on the results of the second step S72 (third step S73).

[0095] In the third step S73 of this embodiment, first, multiple types of conditions (nine types of conditions in this example) input into the condition storage unit 36b shown in FIG. 2 are loaded into the working memory 33. Furthermore, the virus infectivity titer air change rate F determined under the multiple types of conditions input into the infectivity titer air change rate storage unit 36d is loaded into the working memory 33. Furthermore, a third identification unit 43 included in the program unit 37 is loaded into the working memory 33. The third identification unit 43 is a program for determining the relationship between the relative humidity, the virus infectivity titer air change rate, and the air volume (notch) of the first fan 16 based on the results of the second step S72. Execution of this third identification unit 43 by the calculation device 31 allows the control device 17 to function as a means for determining the above relationship.

[0096] In the third step S73, a relationship R can be appropriately specified between the relative humidity H, the virus infectivity air change rate F, and the air volume (notch) A of the first fan 16. The relationship R may include a first relationship R1 between the air relative humidity H and the virus infectivity air change rate F, specified for each air volume (notch) A of the first fan 16. Fig. 7 is a graph showing an example of the first relationship R1.

[0097] In this embodiment, to identify the first relationship R1, first, one airflow rate (e.g., a stop notch) is selected from the airflow rates A (in this example, a strong notch, a weak notch, and a stop notch) of the first fan 16 that constitute a plurality of conditions. Next, the virus infectivity ventilation rates F calculated under conditions that associate the selected airflow rate (stop notch) with a plurality of relative humidities (in this example, 25% RH, 50% RH, and 75% RH) are identified.

[0098] Next, for the selected air volume (stop notch), multiple relative humidities H (in this example, 25% RH, 50% RH, and 75% RH) and the virus infectivity ventilation rates F calculated at those relative humidities H are plotted on the graph shown in FIG. 7. These plots are then connected to obtain a first relationship R1c (shown by a dashed dotted line) identified for the selected air volume (stop notch). In this embodiment, the first relationship R1c connects adjacent plots with a straight line, but is not limited to this and may be obtained, for example, as an approximate straight line or approximate curve of these plots.

[0099] In this embodiment, the first relationships R1a and R1b (shown by the solid and dashed lines) are determined for each of the other airflow rates (strong notch and weak notch) of the first fan 16, based on the same procedure as above.

[0100] In these first relationships R1 (R1a to R1c), the virus infectivity air change rate F in the current space 5 can be identified based on the airflow rate (either high notch, low notch, or off notch) of first fan 16 currently operating and the relative humidity in space 5. As a specific identification procedure, first, from among the multiple first relationships R1, first relationship R1b (shown by the dashed line) obtained at the same airflow rate as the current airflow rate of first fan 16 (for example, low notch) is identified. Then, the virus infectivity air change rate F at the intersection of the identified first relationship R1b and the relative humidity H in space 5 can be identified as the virus infectivity air change rate F in space 5.

[0101] The identified virus infectivity titer air change rate F can be used to determine the infectivity (infection risk) of the virus in the current space 5 shown in Figure 1. As described above, the larger the virus infectivity titer air change rate F, the lower the infectivity (infection risk). In this embodiment, when the virus infectivity titer air change rate F is equal to or greater than the above number (in this example, 5 times / h), it can be determined that the infectivity is low.

[0102] Furthermore, these first relationships R1 (R1a to R1c) can also be used to identify the airflow rate (notch) A of first fan 16 that will make the virus infectivity air change rate F equal to or greater than the above number (in this example, 5 times / h). As a specific identification procedure, first, for each of the multiple first relationships R1a to R1c, the virus infectivity air change rate F corresponding to the current relative humidity H in space 5 (e.g., 55% RH) is determined. Next, of the multiple first relationships R1a to R1c, the first relationship R1 that will make the virus infectivity air change rate F equal to or greater than the above number (in this example, the first relationship R1a with the strong notch and the first relationship R1b with the weak notch) is identified. Then, the airflow rate A of first fan 16 (e.g., the strong notch and the medium notch) when the identified first relationships R1a and R1b are obtained can be identified as the airflow rate (notch) A that will make the virus infectivity air change rate F equal to or greater than the above number.

[0103] In each of these first relationships R1 (R1a to R1c), the lower the relative humidity H, the lower the virus infectivity air change rate F. Therefore, when the virus infectivity air change rate F is less than the above number (5 times / h in this example) due to a decrease in relative humidity H, the air volume (notch) A of first fan 16 is increased. Therefore, in the first ventilation step S22, as in the previous embodiments, the lower the relative humidity H, the larger the air volume (notch) of first fan 16 can be.

[0104] Furthermore, the relationship R is not limited to the first relationship R1 specified for each air volume (notch) A of the first fan 16. The relationship R may include, for example, a second relationship R2 between the air volume (notch) A of the first fan 16 and the air change rate F for each air relative humidity H. Fig. 8 is a graph showing an example of the second relationship R2.

[0105] In this embodiment, to determine the second relationship R2, first, one relative humidity H (e.g., 25% RH) is selected from the air relative humidities H constituting the multiple conditions (in this example, 25% RH, 50% RH, and 75% RH). Next, the virus infectivity ventilation rate F calculated under conditions that associate the selected relative humidity H (25% RH) with multiple airflow rates A of the first fan 16 (in this example, strong notch, weak notch, and off notch) is determined.

[0106] Next, for the selected relative humidity H (25% RH), multiple air volumes A (in this example, strong notch, weak notch, and off notch) and the virus infectivity titer air change rates F calculated at those air volumes A are plotted on the graph shown in Figure 8. These plots are then connected to obtain a second relationship R2c (shown by a dashed dotted line) specified for the selected relative humidity H (25% RH). In this embodiment, the second relationship R2 connects adjacent plots with a straight line, but is not limited to this and may be obtained, for example, as an approximate straight line or approximate curve of these plots.

[0107] In this embodiment, second relationships R2a and R2b (shown by solid and dashed lines) are determined for the other relative humidities (50% RH and 75% RH), respectively, based on the same procedure as above.

[0108] Using these second relationships R2 (R2a to R2c), the virus infectivity air change rate F in the current space 5 can be identified based on the airflow rate of first fan 16 currently operating and the current relative humidity in space 5. As a specific identification procedure, first, from among the multiple second relationships R2, the second relationship R2c with a relative humidity H (e.g., 25% RH) that is the same as or closest to the current relative humidity is identified. Then, in the identified second relationship R2c, the virus infectivity air change rate F corresponding to the current airflow rate of first fan 16 (e.g., weak notch) can be identified as the virus infectivity air change rate F in the current space 5.

[0109] The specified virus infectivity titer air change rate F can be used to determine the infectivity of the virus in the space 5 shown in Figure 1. As described above, the higher the virus infectivity titer air change rate F, the lower the infectivity (infection risk) can be determined to be. In this embodiment, when the virus infectivity titer air change rate F is equal to or greater than the above number (in this example, 5 times / h), the infectivity can be determined to be low.

[0110] Furthermore, these second relationships R2 (R2a to R2c) can also be used to identify, for example, the airflow rate (notch) A of first fan 16 such that virus infectivity air change rate F is equal to or greater than the above number (in this example, 5 times / h). As a specific identification procedure, first, from among the multiple second relationships R2, the second relationship R2c with a relative humidity H (e.g., 25% RH) that is the same as or closest to the relative humidity in the current space 5 is identified. Then, in the identified second relationship R2c, the airflow rate (e.g., strong notch) A of first fan 16 can be identified such that the virus infectivity air change rate F is equal to or greater than the above number (in this example, 5 times / h).

[0111] In each of these second relationships R2 (R2a to R2c), the virus infectivity ventilation rate F decreases as the relative humidity H decreases. Therefore, when the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) due to a decrease in relative humidity H, the air volume (notch) A of first fan 16 is increased. Therefore, in the first ventilation step S22, as in the previous embodiments, the air volume (notch) of first fan 16 can be increased as the relative humidity H decreases.

[0112] In this way, in the relationship acquisition process (relationship acquisition method) of this embodiment, the above relationship R (including the first relationship R1 and the second relationship R2) is determined in advance, making it possible to estimate the virus infectivity titer ventilation rate F without actually measuring the infectivity titer in the house 1 shown in Figure 1.

[0113] The first relationship R1 is not limited to the relative humidity under multiple conditions (25% RH, 50% RH, and 75% RH), and the virus infectivity air change rate F can be estimated from the intersection with the relative humidity H in the current space 5. Therefore, the first relationship R1 can estimate the virus infectivity air change rate F with greater accuracy than the second relationship R2, which is limited to the relative humidity (25% RH, 50% RH, and 75% RH). Therefore, the first relationship R1 is preferably used to determine whether the virus infectivity air change rate F is equal to or greater than the above number (5 times / h in this example).

[0114] The second relationship R2 is not limited to the airflow rate A (strong notch, weak notch, and off notch) of first fan 16 under multiple conditions, and the intersection of the virus infectivity ventilation rate F with the above-mentioned rate (5 times / h) can identify an airflow rate (notch) A of first fan 16 that can be set to or greater than the above-mentioned rate. For this reason, the identified airflow rate (notch) A is effective when setting first fan 16 to be controllable in more stages than the airflow rate A under multiple conditions. Therefore, the second relationship R2 can be used to identify the airflow rate (notch) A of first fan 16 that will set the virus infectivity ventilation rate F to or greater than the above-mentioned rate.

[0115] The manner in which the first relationship R1 and the second relationship R2 are used is not limited to the manner described above. For example, the first relationship R1 may be used to identify the air volume (notch) A of the first fan 16, and the second relationship R2 may be used to determine the virus infectivity titer air change rate F. Furthermore, only the first relationship R1 or only the second relationship R2 may be used to identify the air volume (notch) A of the first fan 16 and to determine the virus infectivity titer air change rate F. The first relationship R1 and the second relationship R2 are input to the relationship storage unit 36e shown in FIG. 2.

[0116] [First ventilation process] Next, an example of the processing procedure of the first ventilation step S22 of another embodiment of the present invention will be described. In the first ventilation step S22 of this embodiment, as in the previous embodiments, the lower the relative humidity of the space 5, the larger the airflow rate (notch) of the first fan 16. This airflow rate (notch) of the first fan 16 is determined based on the relationship R obtained in the relationship acquisition step (relationship acquisition method) so that the virus infectivity ventilation frequency F is equal to or greater than the above frequency (5 times / h in this example).

[0117] In this embodiment, similarly to the previous embodiments, the first ventilation step S22 can be carried out by the calculation device 31 executing the first ventilation section 39 included in the ventilation section 37c of the program section 37 shown in Fig. 2. Fig. 9 is a flowchart showing an example of the processing procedure of the first ventilation step S22 in another embodiment of the present invention.

[0118] [Identify the current viral infectivity ventilation rate F] In the first ventilation step S22 of this embodiment, first, the virus infectivity titer air change rate F in the current space 5 is identified (step S221). In step S221 of this embodiment, the first relationship R1 (shown in FIG. 7) input into the relationship storage unit 36e of FIG. 2 is used to identify the virus infectivity titer air change rate F, but this is not limited to this. For example, the second relationship R2 (shown in FIG. 8) may be used to identify the virus infectivity titer air change rate F.

[0119] The procedure for identifying the virus infectivity titer air change rate F in the current space 5 is as described above. That is, from among the multiple first relationships R1, a first relationship R1b (shown by a dashed line) obtained at the same airflow rate as the current airflow rate of first fan 16 (for example, weak notch) is identified. Then, the virus infectivity titer air change rate F at the intersection of the identified first relationship R1b and the relative humidity H in the current space 5 can be identified as the virus infectivity titer air change rate F in the current space 5. The identified virus infectivity titer air change rate F is input to the infectivity titer air change rate memory unit 36d shown in FIG. 2.

[0120] [Determine whether the viral infectivity ventilation rate is above the specified rate] Next, in the first ventilation step S22 of this embodiment, it is determined whether the current virus infectivity ventilation rate F in the space 5 is equal to or greater than the above rate (5 times / h in this example) (step S222).

[0121] If the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example) ("Yes" in step S222), it is determined that the space 5 is sufficiently ventilated at the current air volume (notch) A of the first fan 16, and that the infectivity of viruses such as influenza viruses is low. In this case, the operation of the first fan 16 is maintained based on the current air volume A of the first fan 16. Note that, based on a procedure similar to that of step S223 described below, if there are multiple air volumes (notches) A ​​of the first fan 16 that result in the virus infectivity ventilation rate F being equal to or greater than the above number, the smallest air volume (notch) A of these air volumes (notches) A ​​may be determined. This can effectively suppress deterioration of the indoor environment, such as noise.

[0122] If the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) ("No" in step S222), it is determined that the current airflow rate (notch) A of the first fan 16 is not sufficient to ventilate the space 5, and that the infectivity of viruses such as influenza viruses is high. In this case, step S223 is performed to determine the airflow rate (notch) A of the first fan 16 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example).

[0123] [Set the air volume so that the virus infectivity ventilation rate is equal to or greater than the specified number of times] Next, in the first ventilation step S22 of this embodiment, the air volume (notch) A of the first fan 16 is determined so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example) (step S223). In step S223 of this embodiment, the second relationship R2 (shown in FIG. 8) input to the relationship storage unit 36e of FIG. 2 is used to determine the air volume (notch) A of the first fan 16, but this is not limited to this. For example, the first relationship R1 (shown in FIG. 7) may be used to determine the air volume (notch) A of the first fan 16.

[0124] The procedure for identifying the airflow rate (notch) A of the first fan 16 is as described above. That is, among the multiple second relationships R2, a second relationship R2c with a relative humidity H (e.g., 25% RH) that is the same as or closest to the relative humidity in the current space 5 is identified. Then, in the identified second relationship R2c, an airflow rate (e.g., a strong notch) A of the first fan 16 that makes the virus infectivity air change rate F equal to or greater than the above number (5 times / h in this example) can be identified. Furthermore, the intersection of the identified second relationship R2c and the above number of virus infectivity air change rates F (5 times / h in this example) may identify the airflow rate (notch) A of the first fan 16 that can make the above number or greater. Furthermore, when multiple notches are identified, it is preferable to determine the smallest notch (e.g., a weak notch) among these notches. This can suppress deterioration of the indoor environment, such as noise.

[0125] [Set fan speed to determined speed] Next, in the first ventilation step S22 of this embodiment, the determined air volume (notch) A is set for the first fan 16 (step S224). In this embodiment, the air volume (notch) A is determined based on the relationship R between the relative humidity H, the virus infectivity ventilation rate F, and the air volume (notch) A of the first fan 16 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example). Setting such air volume A for the first fan 16 makes it possible to reliably reduce the infectivity of viruses in the space 5.

[0126] In this embodiment, when multiple air volumes (notches) A ​​are identified that make the viral infectivity ventilation rate F equal to or greater than the above number (in this example, 5 times / h), the smallest air volume A (for example, a weak notch) among these air volumes (notches) A ​​is determined. This reduces noise during operation of the first fan 16, making it possible to achieve a greater infectious virus countermeasure effect without worsening the indoor environment.

[0127] [Virus reduction system (second embodiment)] In the reduction system 4 of the embodiments described above, the first ventilation fan 16 shown in Fig. 1 is included, but the present invention is not limited to this. Fig. 10 is a cross-sectional view conceptually illustrating an example of a house 1 according to another embodiment of the present invention.

[0128] The reduction system 4 of this embodiment includes, for example, a cleaning fan (hereinafter sometimes referred to as the "second fan") 51 and a filter 52 in addition to the humidity sensor 15 and the control device 17. The humidity sensor 15 and the control device 17 are the same as those in the previous embodiments.

[0129] [Fan (second fan)] The second fan 51 is for supplying air (space air) Ai in the space 5 to the filter 52. In this embodiment, the operation of the second fan 51 can be controlled by the control device 17.

[0130] In this embodiment, the second fan 51 is housed inside the air purifier 53, but is not particularly limited thereto. The second fan 51 is for pressurizing (supplying) the air (space air) Ai inside the air purifier 53 to the space 5 via the outlet 54. This creates a negative pressure inside the air purifier 53, and the space air Ai can be supplied from the supply port 55 to the filter 52 housed inside the air purifier 53.

[0131] The airflow rate of the second fan 51 is controlled in multiple stages. In this embodiment, the airflow rate of the second fan 51 is controlled in multiple stages based on multiple predetermined notches. The notches include, for example, a strong notch, a weak notch, and a stop notch. Of these notches, the strong notch is set to the largest airflow rate per unit time, and the stop notch is set to the smallest airflow rate (corresponding to an air change rate of 0.0 times / h in this example). The airflow rate of each notch is appropriately set depending on, for example, the size of the space 5 (in this example, the living room 6). When the airflow rate of each notch is converted into the air change rate (times / h) of the space 5, it is, for example, the same as that of the fan (first fan) 16, but is not particularly limited thereto.

[0132] Filter The filter 52 is for capturing fine particles contained in the air, such as viruses, bacteria, fine particulate matter, and pollen.

[0133] In order to capture the above-mentioned fine particles, the filter 52 preferably includes at least one of a MEPA filter, a quasi-HEPA filter, a HEPA filter, and a ULPA filter. The filter 52 in this embodiment is configured as a HEPA filter, but may also be configured as another filter, or may be configured including a plurality of these filters.

[0134] The filter 52 of this embodiment is housed in an air purifier 53. This allows the air (space air) Ai in the space 5 to be supplied to the filter 52 and filtered by operating the second fan 51.

[0135] [Air purification in the space] In the reduction system 4 of this embodiment, by operating the second fan 51, the space air Ai is supplied to the filter 52 inside the air purifier 53 via the supply port 55. This allows the space air Ai to be filtered by the filter 52. The space air Ai filtered by the filter 52 is supplied to the space 5 from the exhaust port 54 of the air purifier 53. This cleans the space air Ai.

[0136] In the reduction system 4 of this embodiment, the space air Ai is filtered by the filter 52, thereby capturing particles (including viruses) floating in the space air Ai. As a result, in the reduction system 4 of this embodiment, even if the first ventilation fan 16 shown in FIG. 1 is not provided, the particles floating in the space air Ai are reduced, making it possible to reduce viruses.

[0137] [Findings of the inventors] As a result of extensive research, the inventors have found that increasing the airflow rate of the second fan 51 tends to promote the attenuation of viruses associated with the filtration of the space air Ai by the filter 52 and the inactivation of viruses associated with an increase in the airflow velocity of the space air Ai. They have also found that the lower the relative humidity of the space 5, the greater the airflow rate of the second fan 51, making it possible to maintain the infectivity of viruses (infection risk) low without humidifying the space 5.

[0138] [Virus reduction method (second embodiment)] Based on the above findings, in the reduction method (reduction system 4) of this embodiment, the airflow rate (notch) of the second fan 51 is controlled according to the relative humidity of the space 5. This makes it possible to maintain low viral infectivity without excessively humidifying the space 5 or constantly operating the second fan 51 at a high airflow rate. Therefore, in the reduction method (reduction system 4) of this embodiment, it is possible to expect effective measures against infectious viruses without worsening the indoor environment, such as by increasing mold growth or noise.

[0139] In this embodiment, the processing of each step of the reduction method can be performed by executing a program unit 37 included in the control device 17 of the reduction system 4 shown in Fig. 2 by the arithmetic device 31. Fig. 11 is a flowchart showing an example of the processing procedure of a virus reduction method according to another embodiment of the present invention.

[0140] [Measure the relative humidity of the space] In the reduction method of this embodiment, first, the relative humidity of the space 5 shown in Fig. 10 is measured (step S1). Step S1 can be performed in the same procedure as step S1 in the previous embodiments.

[0141] [Filtering the air in the space (purification process)] Next, in the reduction method of this embodiment, the second fan 51 shown in Fig. 10 is operated to supply air (space air) Ai in the space 5 to the filter 52 and filter it (cleaning step S5). Fig. 12 is a flowchart showing an example of the processing procedure of the cleaning step S5.

[0142] [Determine whether the relative humidity in the space is above the threshold] In the cleaning step S5 of this embodiment, first, it is determined whether the relative humidity of the space 5 shown in FIG. 1 is equal to or lower than a predetermined threshold (step S51). Step S51 of this embodiment can be performed based on the same processing procedure as step S21 shown in FIG. 4. If the relative humidity of the space 5 is equal to or lower than the threshold ("Yes" in step S51), it is determined that the infectivity of the virus in the space 5 is high. In this case, the first cleaning step S52 is performed. On the other hand, if the relative humidity of the space 5 is higher than the threshold ("No" in step S51), it is determined that the infectivity of the virus in the space 5 is low. In this case, the second cleaning step S53 is performed.

[0143] [The lower the relative humidity in the space, the greater the fan's airflow (first cleaning process)] Next, in the cleaning step S5 of this embodiment, the lower the relative humidity in the space 5 shown in FIG. 1, the larger the airflow rate of the second fan 51 is set (first cleaning step S52).

[0144] In the first cleaning step S52 of this embodiment, the relative humidity of the space 5 (shown in FIG. 1) input into the relative humidity storage unit 36a shown in FIG. 2 and a first cleaning unit 44 included in the cleaning unit 37d of the program unit 37 are read into the working memory 33. The first cleaning unit 44 is a program for increasing the airflow rate of the second fan 51 as the relative humidity of the space 5 shown in FIG. 10 decreases. Execution of this first cleaning unit 44 by the calculation device 31 causes the control device 17 to function as a means for increasing the airflow rate as the relative humidity decreases.

[0145] In the first cleaning step S52 of this embodiment, when the operation of the second fan 51 shown in Fig. 10 is stopped, the first cleaning unit 44 (control device 17) shown in Fig. 2 starts the operation of the second fan 51. This allows the space air Ai to be filtered by the filter 52, and the space air Ai can be purified. Furthermore, as in the previous embodiments, when the operation of the air conditioner 19 is stopped, a step (not shown in the flowchart) of conditioning the space air Ai with the air conditioner 19 may be carried out.

[0146] As described above, in this embodiment, when it is determined that the infectivity of the virus is high ("Yes" in step S51), the first cleaning step S52 is performed. In the first cleaning step S52 when it is determined that the infectivity is high, the lower the relative humidity of the space 5, the larger the airflow rate of the second fan 51 is (in this example, the fan is operated at a notch with a larger airflow rate). This promotes the reduction (attenuation) of the virus due to filtration by the filter 52 and the inactivation of the virus due to the increase in the airflow velocity of the space air Ai, thereby maintaining the infectivity of the virus at a low level.

[0147] The airflow rate of the second fan 51 can be set appropriately as long as it can promote the reduction of viruses and maintain the infectivity of the viruses at a low level. The airflow rate of the second fan 51 is preferably set to, for example, an airflow rate equivalent to or greater than the required ventilation rate of the space 5 (0.5 times / h).

[0148] On the other hand, in the first cleaning step S52 of this embodiment, the higher the relative humidity of the space 5 (i.e., the closer the relative humidity is to or below the threshold value and the closer the relative humidity is to the threshold value), the smaller the airflow rate (notch) of the second fan 51 is reduced. In this case, for example, the airflow rate of the second fan 51 (for example, a weak notch) may be set to an airflow rate corresponding to a ventilation rate close to the required ventilation rate of the space 5 (0.5 times / h). This can prevent the indoor environment from being deteriorated due to noise generated when the second fan 51 is operating. Furthermore, an increase in power consumption of the second fan 51 can be prevented.

[0149] As described above, in the first cleaning step S52 (first cleaning unit 44 shown in FIG. 2) of this embodiment, the lower the relative humidity of the space 5, the larger the airflow (notch) of the second fan 51 is made, which can promote the reduction (attenuation) and inactivation of viruses. On the other hand, in the first cleaning step S52 of this embodiment, the higher the relative humidity of the space 5, the smaller the airflow (notch) of the second fan 51 is made, which can reduce noise and power consumption during operation of the second fan 51. As a result, the reduction method (reduction system 4) of this embodiment can be expected to be effective in preventing infectious diseases without worsening the indoor environment.

[0150] If the airflow rate of the second fan 51 is uniformly increased (for example, set to a strong notch) as the relative humidity of the space 5 decreases, the number of viruses will be reduced (infectivity will be reduced), but the noise and power consumption during operation of the second fan 51 will increase. Therefore, in the first cleaning step S52 (first cleaning unit 44 shown in FIG. 2 ), it is preferable to increase the airflow rate (notch) of the second fan 51 in stages as the relative humidity of the space 5 decreases. Similarly, it is preferable to decrease the airflow rate of the second fan 51 in stages as the relative humidity of the space 5 increases. This makes it possible to set the airflow rate of the second fan 51 in a way that can achieve a good balance between the trade-off between "reducing viruses (reducing infectivity)" and "reducing noise and power consumption."

[0151] The airflow rate of the second fan 51 can be set to increase (decrease) in stages as appropriate. For example, as in the previous embodiments, as shown in Fig. 5, an airflow rate (notch) may be specified for each predetermined range of relative humidity so that the airflow rate of the second fan 51 increases in stages as the relative humidity in the space 5 decreases. This allows the airflow rate of the second fan 51 to be uniquely determined according to the relative humidity.

[0152] In the first cleaning step S52 (first cleaning unit 44 shown in FIG. 2) of this embodiment, as shown in FIG. 5, the airflow rate (notch) of the second fan 51 is increased stepwise in response to a decrease in the relative humidity of the space 5. As a result, in the first cleaning step S52 of this embodiment, the airflow rate (notch) of the second fan 51 can be set to achieve a good balance between reducing viruses (reducing infectivity) and reducing noise and power consumption. Therefore, the reduction method (reduction system 4) of this embodiment can be expected to be more effective in preventing infectious viruses without worsening the indoor environment.

[0153] [Set the fan airflow rate based on the required ventilation rate for the space (second cleaning process)] Next, in the cleaning step S5 of this embodiment, the air volume (notch) of the second fan 51 is set based on the air volume corresponding to the required ventilation frequency of the space 5 (second cleaning step S53).

[0154] In the second cleaning step S53 of this embodiment, a second cleaning section 45 included in the cleaning section 37d of the program section 37 shown in Fig. 2 is loaded into the working memory 33. The second cleaning section 45 is a program for setting the air volume (notch) of the second fan 51 based on the air volume corresponding to the required ventilation rate for the space 5 shown in Fig. 10. When the second cleaning section 45 is executed by the calculation device 31, the control device 17 can function as a means for setting the air volume (notch) of the second fan 51 based on the air volume corresponding to the required ventilation rate.

[0155] In the second cleaning step S53 of this embodiment, when the operation of the second fan 51 shown in Fig. 10 is stopped, the second cleaning unit 45 (control device 17) shown in Fig. 2 starts the operation of the second fan 51. This allows the space air Ai to be filtered by the filter 52, and the space air Ai can be purified. Furthermore, as in the previous embodiments, when the operation of the air conditioner 19 is stopped, a step (not shown in the flowchart) of conditioning the space air Ai with the air conditioner 19 may be carried out.

[0156] As described above, in this embodiment, when it is determined that the infectivity of the virus is low ("No" in step S51), the second cleaning step S53 is performed. In the second cleaning step S53 when it is determined that the infectivity is low, the air volume of the second fan 51 (weak notch in this example) is set based on the air volume corresponding to the required ventilation rate of the space 5. This keeps the air volume (notch) of the second fan 51 to the minimum necessary, making it possible to effectively reduce the noise and power consumption of the second fan 51 without deteriorating the effectiveness of measures against infectious viruses.

[0157] [Virus reduction method (another example of the second embodiment)] In the first cleaning step S52 (first cleaning unit 44 shown in FIG. 2) of the embodiments described above, as shown in FIG. 5, attention is focused only on the relative humidity of space 5, and the lower the relative humidity, the larger the airflow rate (notch) of second fan 51 is set, but this is not limiting. For example, the airflow rate (notch) of second fan 51 may be determined based on a previously prepared relationship between the relative humidity, virus infectivity titer air change rate, and the airflow rate (notch) of second fan 51 so that the virus infectivity titer air change rate is equal to or greater than a predetermined number.

[0158] As explained in the previous embodiments, the smaller the virus infectivity ventilation rate F, the higher the virus infectivity. For this reason, it is preferable to determine the air volume (notch) of the second fan 51 so that the virus infectivity ventilation rate F is equal to or greater than a predetermined number. In this embodiment, as in the previous embodiments, the air volume (notch) of the second fan 51 is determined so that the virus infectivity ventilation rate F is equal to or greater than 5 times / h.

[0159] The infectivity of the virus (virus infectivity ventilation rate F) varies depending on the relative humidity of the space 5 and the airflow rate (notch) of the second fan 51. For this reason, it is preferable to determine the airflow rate (notch) of the second fan 51 based on the relationship between the virus infectivity ventilation rate F, the relative humidity, and the airflow rate (notch) of the second fan 51 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example). To enable such determination of the airflow rate of the second fan 51, it is preferable to include a relationship obtaining step of determining the above relationship prior to the cleaning step S5.

[0160] [Relationship Acquisition Process (Relationship Acquisition Method)] Next, the relationship acquisition step (relationship acquisition method) of this embodiment will be described. In this relationship acquisition step, a relationship between the relative humidity, the virus infectivity titer air change rate F, and the airflow rate (notch) of second fan 51, which has been prepared in advance, is acquired. In this embodiment, as in the previous embodiments, the relationship between the virus infectivity titer air change rate F, the relative humidity, and the airflow rate of first fan 16 is preferably acquired in the test chamber described in the above-mentioned document, rather than in house 1 shown in FIG. 10. Furthermore, as in the previous embodiments, the relationship acquisition step (relationship acquisition method) of this embodiment is performed based on the same procedure as the flowchart shown in FIG. 6.

[0161] [Identifying the decay of infectivity titer under multiple conditions (Step 1)] In the relationship acquisition step (relationship acquisition method) of this embodiment, first, the decay over time of the infectivity titer of airborne viruses is identified under a plurality of conditions that associate the airflow rate (notch) of the second fan 51 with the relative humidity of the air (first step S71). In this embodiment, as in the previous embodiments, the first identification unit 41 shown in Fig. 1 is executed by the calculation device 31, causing the control device 17 to function as a means for identifying the decay of the infectivity titer under a plurality of conditions.

[0162] The multiple conditions can be set as appropriate as long as the airflow rate (notch) of the second fan 51 is associated with the relative humidity of the air. In this embodiment, the airflow rate is set to the controllable airflow rate (strong notch, weak notch, and off notch) of the second fan 51 shown in FIG. 10. The relative humidity can be set to the same values ​​as in the previous embodiments (25% RH, 50% RH, and 75% RH), for example. In this embodiment, these three airflow rates (notches) are associated with the three relative humidities, thereby setting nine conditions. Furthermore, the elapsed time t can be set to the same values ​​as in the previous embodiments.

[0163] In the first step S71 of this embodiment, as in the previous embodiments, the attenuation of the infectivity titer (ratio C1 / C t The decay of the infectious titer (ratio C1 / C t ) is input to the infectivity titer attenuation storage unit 36c shown in FIG.

[0164] [Identifying the viral infectivity ventilation rate F under multiple conditions (Step 2)] Next, in the relationship acquisition step (relationship acquisition method) of this embodiment, the virus infectivity titer air change rate F is identified under a plurality of conditions (nine conditions in this example) from the results of the first step S71 (second step S72). In this embodiment, as in the previous embodiments, the second identification unit 42 shown in FIG. 1 is executed by the calculation device 31, causing the control device 17 to function as a means for identifying the virus infectivity titer air change rate F under a plurality of conditions.

[0165] In the second step S72 of this embodiment, the elapsed time t and the decay of the infectivity titer (ratio C1 / C t ) are respectively substituted into the above formula (1). As a result, the virus infectivity titer ventilation rate F is specified for each of the multiple conditions. The specified virus infectivity titer ventilation rate F is input into the infectivity titer ventilation rate memory unit 36d shown in FIG. 2.

[0166] [Identify relationships based on the results of the second step (third step)] Next, in the relationship acquisition step (relationship acquisition method) of this embodiment, the relationship between the relative humidity, the virus infectivity titer ventilation rate, and the air volume (notch) of the second fan 51 is identified based on the result of the second step S72 (third step S73). In this embodiment, as in the previous embodiments, the third identification unit 43 shown in FIG. 1 is executed by the calculation device 31, allowing the control device 17 to function as a means for identifying the above relationship.

[0167] In the third step S73, a relationship R can be appropriately determined among the relative humidity H, the virus infectivity air change rate F, and the air volume (notch) A of the second fan 51. As shown in Fig. 7, the relationship R may include a first relationship R1 between the air relative humidity H and the virus infectivity air change rate F, determined for each air volume (notch) A of the second fan 51. Note that the first relationship R1 can be determined based on the same procedure as in the previous embodiments.

[0168] In the first relationship R1 (R1a to R1c), the virus infectivity air change rate F in the current space 5 can be specified based on the airflow rate (either high notch, low notch, or off notch) of the second fan 51 currently operating and the relative humidity in the current space 5. This virus infectivity air change rate F can be acquired based on the same specification procedure as the virus infectivity air change rate F in the previous embodiments.

[0169] The identified virus infectivity ventilation rate F can be used to determine the infectivity (infection risk) of the virus in the current space 5 shown in Figure 1. In this embodiment, when the virus infectivity ventilation rate F is equal to or greater than the above number (in this example, 5 times / h), it can be determined that the infectivity is low.

[0170] The first relationship R1 (R1a to R1c) can also be used to identify the air volume (notch) A of the second fan 51 such that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example). Such an air volume (notch) of the second fan 51 can be obtained based on the same identification procedure as the air volume (notch) A of the first fan 16 in the previous embodiments.

[0171] In each of these first relationships R1 (R1a to R1c), the lower the relative humidity H, the lower the virus infectivity air change rate F. Therefore, when the virus infectivity air change rate F is less than the above number (5 times / h in this example) due to a decrease in relative humidity H, the air volume (notch) A of the second fan 51 is increased. Therefore, in the first cleaning step S52, as in the previous embodiments, the lower the relative humidity H, the larger the air volume (notch) of the second fan 51 can be.

[0172] Furthermore, the relationship R is not limited to the first relationship R1 determined for each air volume (notch) A of the second fan 51. The relationship R may include a second relationship R2 between the air volume (notch) A of the second fan 51 and the virus infectivity ventilation rate F determined for each air relative humidity H, as shown in Fig. 8. The second relationship R2 can be determined based on the same procedure as in the previous embodiments.

[0173] In the second relationship R2 (R2a to R2c), the virus infectivity air change rate F in the current space 5 can be specified based on the airflow rate of the second fan 51 currently operating (either high notch, low notch, or off notch) and the relative humidity in the current space 5 (either 25%, 50%, or 75% RH). This virus infectivity air change rate F can be obtained based on the same specification procedure as the virus infectivity air change rate F in the previous embodiments.

[0174] The identified virus infectivity ventilation rate F can be used to determine the infectivity (infection risk) of the virus in the current space 5 shown in Figure 1. In this embodiment, when the virus infectivity ventilation rate F is equal to or greater than the above number (in this example, 5 times / h), it can be determined that the infectivity is low.

[0175] The second relationship R2 (R2a to R2c) can also be used to identify the air volume (notch) A of the second fan 51 such that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example). Such air volume (notch) A of the second fan 51 can be obtained based on the same identification procedure as for the air volume (notch) A of the first fan 16 in the previous embodiments.

[0176] In each of these second relationships R2 (R2a to R2c), the virus infectivity ventilation rate F decreases as the relative humidity H decreases. Therefore, when the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) due to a decrease in relative humidity H, the air volume (notch) A of the second fan 51 is increased. Therefore, in the first cleaning step S52, as in the previous embodiments, the air volume (notch) of the second fan 51 can be increased as the relative humidity H decreases.

[0177] In this way, in the relationship acquisition process (relationship acquisition method) of this embodiment, the above relationship R (including the first relationship R1 and the second relationship R2) is determined in advance, making it possible to estimate the virus infectivity titer ventilation rate F without actually measuring the infectivity titer in the house 1 shown in Figure 1.

[0178] The first relationship R1 can estimate the virus infectivity air change rate F with greater accuracy than the second relationship R2, which is limited to relative humidity (25% RH, 50% RH, and 75% RH). Therefore, the first relationship R1 is preferably used to determine whether the virus infectivity air change rate F is equal to or greater than the above-mentioned rate (5 times / h in this example). On the other hand, the second relationship R2 can be used to identify the air volume (notch) A of the second fan 51 that will result in the virus infectivity air change rate F being equal to or greater than the above-mentioned rate.

[0179] The manner in which the first relationship R1 and the second relationship R2 are used is not limited to the manner described above. For example, the first relationship R1 may be used to identify the air volume (notch) A of the second fan 51, and the second relationship R2 may be used to determine the virus infectivity titer air change rate F. Furthermore, only the first relationship R1 or only the second relationship R2 may be used to identify the air volume (notch) A of the second fan 51 and to determine the virus infectivity titer air change rate F. The first relationship R1 and the second relationship R2 are input to the relationship storage unit 36e shown in FIG. 2.

[0180] [First cleaning process] Next, an example of the processing procedure of the first cleaning step S52 of another embodiment of the present invention will be described. In the first cleaning step S52 of this embodiment, as in the previous embodiments, the lower the relative humidity of the space 5, the larger the airflow rate (notch) of the second fan 51. This airflow rate (notch) of the second fan 51 is determined based on the relationship R obtained in the relationship obtaining step (relationship obtaining method) so that the virus infectivity ventilation rate F is equal to or greater than the above number of times (5 times / h in this example).

[0181] In this embodiment, similarly to the previous embodiments, the first cleaning step S52 can be performed by the first cleaning unit 44 included in the cleaning unit 37d of the program unit 37 shown in Fig. 2 being executed by the arithmetic device 31. Fig. 13 is a flowchart showing an example of the processing procedure for the first cleaning step S52 according to another embodiment of the present invention.

[0182] [Identify the current viral infectivity ventilation rate F] In the first cleaning step S52 of this embodiment, first, the virus infectivity titer air change rate F in the current space 5 is identified (step S521). In this embodiment, for example, from among the multiple first relationships R1 shown in FIG. 7, a first relationship R1b (shown by a dashed line) of an air volume identical to the current air volume of the second fan 51 (for example, weak notch) is identified. Then, the virus infectivity titer air change rate F at the intersection of the identified first relationship R1b and the relative humidity H in the current space 5 can be identified as the virus infectivity titer air change rate F in the current space 5. The identified virus infectivity titer air change rate F is input to the infectivity titer air change rate memory unit 36d shown in FIG.

[0183] [Determine whether the viral infectivity ventilation rate is above the specified rate] Next, in the first cleaning step S52 of this embodiment, it is determined whether the current virus infectivity ventilation rate F in the space 5 is equal to or greater than the above rate (5 times / h in this example) (step S522).

[0184] If the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example) ("Yes" in step S222), it is determined that the space 5 is sufficiently purified at the current air volume (notch) A of the second fan 51, and that the infectivity of viruses such as influenza viruses is low. In this case, the operation of the second fan 51 is maintained based on the current air volume A of the second fan 51. Note that, if there are multiple air volumes (notches) A ​​of the second fan 51 that result in the virus infectivity ventilation rate F being equal to or greater than the above number, the smallest air volume (notch) A of these air volumes (notches) A ​​may be determined based on a procedure similar to that of step S523 described below. This can effectively suppress deterioration of the indoor environment, such as noise.

[0185] If the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) ("No" in step S522), it is determined that the current airflow rate (notch) A of the second fan 51 is not sufficient to purify the space 5, and that the infectivity of viruses such as influenza viruses is high. In this case, step S523 is performed to determine the airflow rate (notch) A of the second fan 51 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example).

[0186] [Set the air volume so that the virus infectivity ventilation rate is equal to or greater than the specified number of times] Next, in the first cleaning step S52 of this embodiment, the air volume (notch) A of the second fan 51 is determined so that the virus infectivity ventilation rate F is equal to or greater than the above rate (5 times / h in this example) (step S523).

[0187] In this embodiment, for example, from among the multiple second relationships R2 shown in FIG. 8, a second relationship R2c is identified that has a relative humidity H (e.g., 25% RH) that is the same as or closest to the relative humidity in the current space 5. Then, in the identified second relationship R2c, an airflow rate (e.g., a strong notch) A of the second fan 51 that makes the virus infectivity ventilation rate F equal to or greater than the above-mentioned number (5 times / h in this example) can be identified. Furthermore, the airflow rate (notch) A of the second fan 51 that can make the virus infectivity ventilation rate F equal to or greater than the above-mentioned number may be identified from the intersection of the identified second relationship R2c and the above-mentioned number of virus infectivity ventilation rates F (5 times / h in this example). Furthermore, when multiple notches are identified, it is preferable to determine the smallest notch (e.g., a weak notch) among these notches. This can suppress deterioration of the indoor environment, such as noise.

[0188] [Set fan speed to determined speed] Next, in the first cleaning step S52 of this embodiment, the determined air volume (notch) A is set for the second fan 51 (step S524). In this embodiment, the air volume (notch) A is determined based on the relationship R between the relative humidity H, the virus infectivity air change rate F, and the air volume (notch) A of the second fan 51 so that the virus infectivity air change rate F is equal to or greater than the above number (5 times / h in this example). Setting such air volume A for the second fan 51 makes it possible to reliably reduce the infectivity of viruses in the space 5.

[0189] In this embodiment, when multiple air volumes (notches) A ​​are identified that make the viral infectivity ventilation rate F equal to or greater than the above number (in this example, 5 times / h), the smallest air volume A (for example, a weak notch) among these air volumes (notches) A ​​is determined. This reduces noise during operation of the second fan 51, making it possible to achieve a greater infectious virus countermeasure effect without worsening the indoor environment.

[0190] [Virus reduction system (third embodiment)] The reduction system 4 in the above-described embodiments has been exemplified as including the ventilation fan (first fan) 16 shown in Fig. 1 and including the second cleaning fan 51 and filter 52 shown in Fig. 10, but is not limited to these. Fig. 14 is a cross-sectional view conceptually showing an example of a house 1 according to yet another embodiment of the present invention.

[0191] The reduction system 4 of this embodiment includes, for example, the ventilation fan (first fan) 16 shown in Fig. 1 and the cleaning second fan 51 and filter 52 shown in Fig. 10. As in the previous embodiments, the reduction system 4 of this embodiment also includes a humidity sensor 15 and a control device 17. In this embodiment, the first fan 16, the second fan 51, the filter 52, the humidity sensor 15, and the control device 17 are the same as in the previous embodiments.

[0192] [Space ventilation and air purification] In the reduction system 4 of this embodiment, similarly to the previous embodiments, by operating the first fan 16, outside air Ao is supplied to the space 5 and space air Ai is exhausted to the outdoors 27. This replaces the space air Ai, and the space 5 (above-floor space 2) can be ventilated.

[0193] Furthermore, in the reduction system 4 of this embodiment, as in the previous embodiments, the second fan 51 is operated to filter the space air Ai by the filter 52, and the filtered space air Ai is supplied to the space 5. This purifies the space air Ai.

[0194] In this manner, in the reduction system 4 of this embodiment, by ventilating the space 5 and purifying the space air Ai, the particles (including viruses) floating in the space air Ai can be captured while being discharged to the outdoors 27. As a result, in the reduction system 4 of this embodiment, the particles floating in the space air Ai are further reduced, enabling further reduction of viruses.

[0195] [Findings of the inventors] As a result of extensive research, the inventors have found that increasing the airflow rates of both the first fan 16 and the second fan 51 tends to promote the attenuation of viruses associated with the replacement and filtration of the space air Ai and the inactivation of viruses associated with an increase in the airflow velocity of the space air Ai. They have also found that the lower the relative humidity of the space 5, the lower the infectivity of viruses (infection risk) can be maintained without humidifying the space 5 by increasing the airflow rates of both the first fan 16 and the second fan 51.

[0196] [Virus reduction method (third embodiment)] Based on the above findings, the reduction method (reduction system 4) of this embodiment controls the airflow (notch) of the first fan 16 and the second fan 51 according to the relative humidity of the space 5. This makes it possible to maintain low viral infectivity without excessively humidifying the space 5 or constantly operating the first fan 16 and the second fan 51 at high airflow rates. Therefore, the reduction method (reduction system 4) of this embodiment can be expected to be effective in preventing infectious viruses without worsening the indoor environment through factors such as mold growth and noise.

[0197] In this embodiment, the processing of each step of the reduction method can be performed by having the program unit 37 included in the control device 17 of the reduction system 4 shown in Fig. 2 executed by the arithmetic device 31. Fig. 15 is a flowchart showing an example of the processing procedure of a virus reduction method according to yet another embodiment of the present invention.

[0198] [Measure the relative humidity of the space] In the reduction method of this embodiment, first, the relative humidity of the space 5 shown in Fig. 14 is measured (step S1). Step S1 can be performed in the same procedure as step S1 in the previous embodiments.

[0199] [Replacing the air in the space and ventilating it (ventilation process)] Next, in the reduction method of this embodiment, the air (space air) Ai in the space 5 shown in Fig. 14 is replaced and ventilated (ventilation step S2). In the ventilation step S2 of this embodiment, as in the previous embodiments, the space air Ai is replaced and the space 5 is ventilated by operating the fan (first fan) 16.

[0200] The ventilation step S2 of this embodiment is performed based on the procedure shown in Fig. 4, as in the previous embodiments. Therefore, in the ventilation step S2, if the relative humidity in the space 5 is equal to or lower than the threshold value ("Yes" in step S21), the virus is determined to be highly infective, and the first ventilation step S22 is performed. On the other hand, if the relative humidity in the space 5 is higher than the threshold value ("No" in step S21), the virus is determined to be low infective in the space 5, and the second ventilation step S23 is performed.

[0201] In the first ventilation step S22, the lower the relative humidity of the space 5, the greater the airflow rate of the first fan 16. This promotes virus reduction (attenuation) due to the replacement of the space air Ai and virus inactivation due to the increased airflow velocity of the space air Ai, thereby maintaining low viral infectivity. Furthermore, in the first ventilation step S22, as shown in FIG. 5, it is preferable to increase the airflow rate (notch) of the first fan 16 in stages according to the decrease in the relative humidity of the space 5. This makes it possible for the reduction method (reduction system 4) of this embodiment to be effective in preventing infectious viruses without worsening the indoor environment.

[0202] In the second ventilation step S23, the air volume (notch) of the first fan 16 is set based on the required ventilation rate of the space 5. This keeps the air volume (notch) of the first fan 16 to the minimum required, making it possible to effectively suppress the noise and power consumption of the first fan 16 without deteriorating the effectiveness of measures against infectious diseases.

[0203] [Filtering the air in the space (purification process)] Next, in the reduction method of this embodiment, a second fan 51 different from the first fan 16 shown in FIG. 14 is operated so that the air (space air) Ai in the space 5 is supplied to the filter 52 and filtered (cleaning process S5).

[0204] The cleaning step S5 is performed based on the processing procedure shown in Fig. 12. Therefore, in the cleaning step S5, if the relative humidity in the space 5 is equal to or lower than the threshold value ("Yes" in step S51), the virus is determined to be highly infective, and the first cleaning step S52 is performed. On the other hand, if the relative humidity in the space 5 is higher than the threshold value ("No" in step S51), the virus is determined to be low infective in the space 5, and the second cleaning step S53 is performed.

[0205] In the first cleaning step S52, the lower the relative humidity of the space 5, the greater the airflow rate of the second fan 51. This promotes virus reduction (attenuation) due to filtration by the filter 52 and virus inactivation due to an increase in the airflow velocity of the space air Ai, thereby maintaining low viral infectivity. Furthermore, in the first cleaning step S52, as shown in FIG. 5, it is preferable to increase the airflow rate (notch) of the second fan 51 in stages according to a decrease in the relative humidity of the space 5. This makes it possible for the reduction method (reduction system 4) of this embodiment to be effective in preventing infectious viruses without worsening the indoor environment.

[0206] In the second cleaning step S53, the air volume (notch) of the second fan 51 is set based on the required ventilation rate of the space 5. This keeps the air volume (notch) of the second fan 51 to the minimum required, making it possible to effectively suppress the noise and power consumption of the second fan 51 without deteriorating the effectiveness of measures against infectious diseases.

[0207] As described above, in the reduction method of this embodiment, by performing both the ventilation step S2 and the cleaning step S5, particles (including viruses) floating in the space air Ai can be collected while being exhausted to the outdoors 27. As a result, the ventilation method (reduction system 4) of this embodiment further reduces the number of particles floating in the space air Ai, enabling further reduction of viruses. Furthermore, in the reduction method of this embodiment, by operating both the first fan 16 and the second fan 51, the airflow velocity of the space air Ai can be further increased, further promoting the inactivation of viruses. Therefore, the ventilation method (reduction system 4) of this embodiment can be expected to be effective in preventing infectious viruses without worsening the indoor environment. Note that the embodiment is not limited to the embodiment in which the cleaning step S5 is performed after the ventilation step S2, as shown in FIG. 15 . For example, the ventilation step S2 may be performed after the cleaning step S5, or the ventilation step S2 and the cleaning step S5 may be performed simultaneously.

[0208] [Virus reduction method (another example of the third embodiment)] In the embodiments described above, in the first ventilation step S22 and the first cleaning step S52, attention is focused only on the relative humidity of the space 5 shown in Fig. 5, and the lower the relative humidity, the greater the airflow rates of the first fan 16 and the second fan 51. However, this is not limiting. For example, the airflow rates of the first fan 16 and the second fan 51 may be determined based on a previously prepared relationship between the relative humidity, the virus infectivity titer air change rate, and the fan airflow rates (the combination of the airflow rates of the first fan 16 and the second fan 51) so that the virus infectivity titer air change rate is equal to or greater than the aforementioned rate.

[0209] As explained in the previous embodiments, the smaller the virus infectivity ventilation rate F, the higher the virus infectivity. Therefore, it is preferable to determine the air volume of the first fan 16 and the air volume of the second fan 51 so that the virus infectivity ventilation rate F is equal to or greater than a predetermined number. In this embodiment, as in the previous embodiments, the air volume of the first fan 16 and the air volume of the second fan 51 are determined so that the virus infectivity ventilation rate F is equal to or greater than 5 times / h.

[0210] The infectivity of a virus (virus infectivity ventilation rate F) varies depending on the relative humidity of the space 5 and the airflow rate of the fans (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51). Therefore, it is preferable to determine the airflow rate of the first fan 16 and the airflow rate of the second fan 51 based on the relationship between the virus infectivity ventilation rate F, the relative humidity, and the airflow rate of the fans (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h). To enable such determination of the airflow rates of the first fan 16 and the second fan 51, it is preferable to include a relationship obtaining step of determining the above relationship prior to the cleaning step S5.

[0211] [Relationship Acquisition Process (Relationship Acquisition Method)] Next, the relationship acquisition step (relationship acquisition method) of this embodiment will be described. In this relationship acquisition step, a previously prepared relationship between the relative humidity, the virus infectivity titer air change rate F, and the fan airflow rate (the combination of the airflow rate of first fan 16 and the airflow rate of second fan 51) is acquired. In this embodiment, as in the previous embodiments, the relationship between the virus infectivity titer air change rate F, the relative humidity, and the fan airflow rate (the combination of the airflow rate of first fan 16 and the airflow rate of second fan 51) is preferably acquired in the test chamber described in the above-mentioned document, rather than in house 1 shown in FIG. 14. Furthermore, as in the previous embodiments, the relationship acquisition step (relationship acquisition method) of this embodiment is performed based on the same procedure as the flowchart shown in FIG. 6.

[0212] [Identifying the decay of infectivity titer under multiple conditions (Step 1)] In the relationship acquisition step (relationship acquisition method) of this embodiment, first, the decay over time of the infectivity titer of airborne viruses is identified under a plurality of conditions correlating the fan airflow rates (combinations of the airflow rates of the first fan 16 and the second fan 51) with the relative humidity of the air (first step S71). In this embodiment, as in the previous embodiments, the first identification unit 41 shown in Fig. 1 is executed by the arithmetic device 31, allowing the control device 17 to function as a means for identifying the decay of the infectivity titer under a plurality of conditions.

[0213] The multiple conditions can be set as appropriate as long as the fan airflow rates (combinations of the airflow rates of the first fan 16 and the second fan 51) are associated with the relative humidity of the air. In this embodiment, the airflow rates are set as combinations (nine types in this example) of the airflow rates (strong notch, weak notch, and stop notch) that can be controlled by the first fan 16 shown in FIG. 14 and the airflow rates (strong notch, weak notch, and stop notch) that can be controlled by the second fan 51. The relative humidity can be set, for example, to the same values ​​as in the previous embodiments (25% RH, 50% RH, and 75% RH). In this embodiment, these nine airflow rates (notches) are associated with three relative humidities, thereby setting 27 types of conditions. The elapsed time t can be set as in the previous embodiments.

[0214] In the first step S71 of this embodiment, as in the previous embodiments, the attenuation of the infectivity titer (ratio C1 / C t The decay of the infectious titer (ratio C1 / C t ) is input to the infectivity titer attenuation storage unit 36c shown in FIG.

[0215] [Identifying the viral infectivity ventilation rate F under multiple conditions (Step 2)] Next, in the relationship acquisition step (relationship acquisition method) of this embodiment, the virus infectivity titer air change rate F is identified under a plurality of conditions (27 conditions in this example) from the results of the first step S71 (second step S72). In this embodiment, as in the previous embodiments, the second identification unit 42 shown in FIG. 1 is executed by the calculation device 31, causing the control device 17 to function as a means for identifying the virus infectivity titer air change rate F under a plurality of conditions.

[0216] In the second step S72 of this embodiment, the elapsed time t and the decay of the infectivity titer (ratio C1 / C t) are respectively substituted into the above formula (1). As a result, the virus infectivity titer ventilation rate F is specified for each of the multiple conditions. The specified virus infectivity titer ventilation rate F is input into the infectivity titer ventilation rate memory unit 36d shown in FIG. 2.

[0217] [Identify relationships based on the results of the second step (third step)] Next, in the relationship acquisition step (relationship acquisition method) of this embodiment, the relationship between the relative humidity, the virus infectivity ventilation rate, and the fan airflow rate (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) is identified based on the result of the second step S72 (third step S73). In this embodiment, as in the previous embodiments, the third identification unit 43 shown in FIG. 1 is executed by the calculation device 31, allowing the control device 17 to function as a means for identifying the above relationship.

[0218] In the third step S73, a relationship R between the relative humidity H, the virus infectivity air change rate F, and the fan airflow rate A (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) can be appropriately specified. The relationship R may include a first relationship R1 between the air relative humidity H and the virus infectivity air change rate F, specified for each fan airflow rate A (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51). FIG. 16 is a graph showing an example of the first relationship according to another embodiment of the present invention.

[0219] The first relationship R1 can be determined based on the same procedure as in the previous embodiments. In Fig. 16, a combination of the strong notch of the first fan 16 and the stop notch of the second fan 51, a combination of the weak notch of the first fan 16 and the stop notch of the second fan 51, and a combination of the stop notch of the first fan 16 and the stop notch of the second fan 51 are shown as representative examples.

[0220] In the first relationship R1, the virus infectivity air change rate F in the current space 5 can be determined based on the airflow rate A of the currently operating fans (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) and the current relative humidity in the space 5. This virus infectivity air change rate F can be obtained based on the same determination procedure as the virus infectivity air change rate F in the previous embodiments.

[0221] The identified virus infectivity ventilation rate F can be used to determine the infectivity (infection risk) of the virus in the current space 5 shown in Figure 1. In this embodiment, when the virus infectivity ventilation rate F is equal to or greater than the above number (in this example, 5 times / h), it can be determined that the infectivity is low.

[0222] The first relationship R1 can also be used, for example, to identify the fan airflow rate A (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) such that the virus infectivity air change rate F is equal to or greater than the above number (in this example, 5 times / h). As a specific identification procedure, first, for each of the multiple first relationships R1, the virus infectivity air change rate F corresponding to the current relative humidity H in the space 5 (for example, 55% RH) is determined. Next, of the multiple first relationships R1, the first relationship R1 that results in the virus infectivity air change rate F being equal to or greater than the above number is identified. In this example, the first relationship R1a (first fan: strong notch, second fan: off notch) and the first relationship R1b (first fan: weak notch, second fan: off notch) shown in FIG. 16 are identified. Then, it can be determined that the combination of the air volume of the first fan 16 and the air volume of the second fan 51 in the determined first relationships R1a and R1b can make the virus infectivity ventilation rate F equal to or greater than the above-described rate.

[0223] In each of these first relationships R1 (first relationships R1a to R1c in FIG. 16), the virus infectivity titer air change rate F decreases as the relative humidity H decreases. Therefore, the lower the relative humidity H, the greater the airflow of the fans (the combination of the airflow of first fan 16 and the airflow of second fan 51) is increased when the virus infectivity titer air change rate F is less than the above number (5 times / h in this example). Therefore, in the first ventilation step S22 (shown in FIG. 9) and the first cleaning step S52 (shown in FIG. 13), the lower the relative humidity H, the greater the airflow of first fan 16 (the airflow of first fan 16 and / or the airflow of second fan 51) can be increased, as in the previous embodiments.

[0224] Furthermore, the relationship R is not limited to the first relationship R1 specified for each fan air volume (a combination of the air volume of the first fan 16 and the air volume of the second fan 51). The relationship R may include, for example, a second relationship R2 between the fan air volume A (a combination of the air volume of the first fan 16 and the air volume of the second fan 51) and the virus infectivity ventilation rate F specified for each air relative humidity H. Fig. 17 is a graph showing an example of the second relationship R2 according to another embodiment of the present invention.

[0225] The second relationship R2 can be determined based on the same procedure as in the previous embodiments. In Fig. 17, a combination of the strong notch of the first fan 16 and the stop notch of the second fan 51, a combination of the weak notch of the first fan 16 and the stop notch of the second fan 51, and a combination of the stop notch of the first fan 16 and the stop notch of the second fan 51 are shown as representative examples.

[0226] In the second relationship R2, the virus infectivity air change rate F in the current space 5 can be determined based on the airflow rates of the currently operating fans (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) and the current relative humidity in the space 5 (any of 25%, 50%, or 75% RH). This virus infectivity air change rate F can be obtained based on the same determination procedure as for the virus infectivity air change rate F in the previous embodiments.

[0227] The identified virus infectivity ventilation rate F can be used to determine the infectivity (infection risk) of the virus in the current space 5 shown in Figure 1. In this embodiment, when the virus infectivity ventilation rate F is equal to or greater than the above number (in this example, 5 times / h), it can be determined that the infectivity is low.

[0228] The second relationship R2 can also be used, for example, to identify the airflow rate (notch) A of the second fan 51 that will make the virus infectivity air change rate F equal to or greater than the above number (in this example, 5 times / h). As a specific identification procedure, first, from among the multiple second relationships R2, a second relationship R2c is identified that has a relative humidity H (e.g., 25% RH) that is the same as or closest to the relative humidity in the current space 5. Then, in the identified second relationship R2c, a fan airflow rate A (a combination of the airflow rate (strong notch) of the first fan 16 and the airflow rate (stop notch) of the second fan 51) that will make the virus infectivity air change rate F equal to or greater than the above number (in this example, 5 times / h) can be identified.

[0229] In each of these second relationships R2 (second relationships R2a to R2c in FIG. 17), the virus infectivity ventilation rate F decreases as the relative humidity H decreases. Therefore, when the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) due to a decrease in relative humidity H, the airflow of the fans (the combination of the airflow of first fan 16 and the airflow of second fan 51) is increased. Therefore, in the first ventilation step S22 (shown in FIG. 9) and the first cleaning step S52 (shown in FIG. 13), the airflow of the fans (the airflow of first fan 16 and / or the airflow of second fan 51) can be increased as the relative humidity H decreases, as in the previous embodiments.

[0230] In this way, in the relationship acquisition process (relationship acquisition method) of this embodiment, the above relationship R (including the first relationship R1 and the second relationship R2) is determined in advance, making it possible to estimate the virus infectivity titer ventilation rate F without actually measuring the infectivity titer in the house 1 shown in Figure 1.

[0231] The first relationship R1 can estimate the virus infectivity air change rate F with greater accuracy than the second relationship R2, which is limited to relative humidity (25% RH, 50% RH, and 75% RH). Therefore, the first relationship R1 is preferably used to determine whether the virus infectivity air change rate F is equal to or greater than the above-mentioned rate (5 times / h in this example). On the other hand, the second relationship R2 can be used to identify the fan airflow rate A (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) that will make the virus infectivity air change rate F equal to or greater than the above-mentioned rate.

[0232] The manner in which the first relationship R1 and the second relationship R2 are used is not limited to the manner described above. For example, the first relationship R1 may be used to identify the fan airflow rate A (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51), and the second relationship R2 may be used to determine the virus infectivity titer air change rate F. Furthermore, either only the first relationship R1 or only the second relationship R2 may be used to identify the fan airflow rate A (the combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) and to determine the virus infectivity titer air change rate F. The first relationship R1 and the second relationship R2 are input to the relationship storage unit 36e shown in FIG. 2.

[0233] [First ventilation process] Next, an example of the processing procedure of the first cleaning step S52 of this embodiment will be described. In the first ventilation step S22 of this embodiment, as in the previous embodiments, the air volume (notch) of the first fan 16 is increased as the relative humidity of the space 5 decreases. This air volume (notch) of the first fan 16 is determined based on the relationship R (shown in FIGS. 16 and 17) obtained in the relationship acquisition step (relationship acquisition method) so that the virus infectivity ventilation frequency F is equal to or greater than the above frequency (5 times / h in this example).

[0234] In this embodiment, similarly to the previous embodiments, the first ventilation step S22 can be performed by the first ventilation section 39 included in the ventilation section 37c of the program section 37 shown in Fig. 2 being executed by the arithmetic device 31. The first ventilation step S22 of this embodiment is performed based on the processing procedure shown in Fig. 9.

[0235] [Identify the current viral infectivity ventilation rate F] In the first ventilation step S22 of this embodiment, first, the virus infectivity titer air change rate F in the current space 5 is identified (step S221). In this embodiment, for example, from among the multiple first relationships R1 shown in FIG. 16 , a first relationship R1 (for example, first relationship R1b shown by a dashed line) that is identical to the current fan airflow rate (the combination of the airflow rate of first fan 16 and the airflow rate of second fan 51) is identified. Then, the virus infectivity titer air change rate F at the intersection of the identified first relationship R1b and the relative humidity H in the current space 5 can be identified as the virus infectivity titer air change rate F in the current space 5. The identified virus infectivity titer air change rate F is input to the infectivity titer air change rate memory unit 36d shown in FIG. 2.

[0236] [Determine whether the viral infectivity ventilation rate is above the specified rate] Next, in the first ventilation step S22 of this embodiment, it is determined whether the current virus infectivity ventilation rate F in the space 5 is equal to or greater than the above rate (5 times / h in this example) (step S222).

[0237] If the virus infectivity ventilation rate F is equal to or greater than the above number (in this example, 5 times / h) ("Yes" in step S222), the space 5 is sufficiently ventilated at the current fan airflow rate A (the combination of the airflow rates of the first fan 16 and the second fan 51). Therefore, it is determined that the infectivity of viruses such as influenza viruses is low. In this case, the operation of the first fan 16 is maintained based on the current fan airflow rate A (the combination of the airflow rates of the first fan 16 and the second fan 51).

[0238] If the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) ("No" in step S222), the current fan airflow rate A (the combination of the airflow rates of the first fan 16 and the second fan 51) is not sufficient to ventilate the space 5. Therefore, it is determined that the infectivity of viruses such as influenza viruses is high. In this case, step S223 is performed to determine the airflow rate (notch) A of the first fan 16 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example).

[0239] [Set the air volume so that the virus infectivity ventilation rate is equal to or greater than the specified number of times] Next, in the first ventilation step S22 of this embodiment, the air volume (notch) A of the first fan 16 is determined so that the virus infectivity ventilation rate F is equal to or greater than the above rate (5 times / h in this example) (step S223).

[0240] In this embodiment, for example, from among the multiple second relationships R2 shown in FIG. 17, a second relationship R2c is identified that has a relative humidity H (e.g., 25% RH) that is the same as or closest to the relative humidity in the current space 5. Then, in the identified second relationship R2c, a fan airflow rate A (a combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) that makes the virus infectivity air change rate F equal to or greater than the above number (5 times / h in this example) can be identified. Furthermore, from the intersection of the identified second relationship R2c and the above number of virus infectivity air changes F (5 times / h in this example), a fan airflow rate A (a combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) that can make the virus infectivity air change rate F equal to or greater than the above number can be identified. Then, the airflow rate of the first fan 16 included in this identified combination can be determined as the airflow rate (notch) of the first fan 16 that can make the virus infectivity air change rate F equal to or greater than the above number (5 times / h in this example).

[0241] [Set fan speed to determined speed] Next, in the first ventilation step S22 of this embodiment, the determined air volume A is set for the first fan 16 (step S224). In this embodiment, the air volume (notch) A of the first fan 16 is determined based on the relationship R between the relative humidity H, the virus infectivity ventilation rate F, and the fan air volume A (the combination of the air volumes of the first fan 16 and the second fan 51) so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h). Setting such air volume A for the first fan 16 makes it possible to reliably reduce the infectivity of viruses in the space 5. Therefore, the reduction method of this embodiment makes it possible to more effectively combat infectious viruses without worsening the indoor environment.

[0242] [First cleaning process] Next, an example of the processing procedure of the first cleaning step S52 of this embodiment will be described. In the first cleaning step S52 of this embodiment, as in the previous embodiments, the lower the relative humidity of the space 5, the larger the airflow rate (notch) of the second fan 51. This airflow rate (notch) of the second fan 51 is determined based on the relationship R (shown in FIGS. 16 and 17) obtained in the relationship acquisition step (relationship acquisition method) so that the virus infectivity ventilation rate F is equal to or greater than the above number of times (5 times / h in this example).

[0243] In this embodiment, similarly to the previous embodiments, the first cleaning step S52 can be performed by the first cleaning unit 44 included in the cleaning unit 37d of the program unit 37 shown in Fig. 2 being executed by the arithmetic device 31. The first cleaning step S52 in this embodiment is performed based on the processing procedure shown in Fig. 13.

[0244] [Identify the current viral infectivity ventilation rate F] In the first cleaning step S52 of this embodiment, first, the virus infectivity titer air change rate F in the current space 5 is identified (step S521). In this embodiment, for example, from among the multiple first relationships R1 shown in FIG. 16 , a first relationship R1 (for example, first relationship R1b shown by a dashed line) that is identical to the current fan airflow rate (the combination of the airflow rate of first fan 16 and the airflow rate of second fan 51) is identified. Then, the virus infectivity titer air change rate F at the intersection of the identified first relationship R1b and the relative humidity H in the current space 5 can be identified as the virus infectivity titer air change rate F in the current space 5. The identified virus infectivity titer air change rate F is input to the infectivity titer air change rate memory unit 36d shown in FIG. 2.

[0245] [Determine whether the viral infectivity ventilation rate is above the specified rate] Next, in the first cleaning step S52 of this embodiment, it is determined whether the current virus infectivity ventilation rate F in the space 5 is equal to or greater than the above rate (5 times / h in this example) (step S522).

[0246] If the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example) ("Yes" in step S522), the space 5 is sufficiently ventilated at the current fan airflow rate A (the combination of the airflow rates of the first fan 16 and the second fan 51). Therefore, it is determined that the infectivity of viruses such as influenza viruses is low. In this case, the operation of the second fan 51 is maintained based on the current fan airflow rate A (the combination of the airflow rates of the first fan 16 and the second fan 51).

[0247] If the virus infectivity ventilation rate F is less than the above number (5 times / h in this example) ("No" in step S522), the current fan airflow rate A (the combination of the airflow rates of the first fan 16 and the second fan 51) is not sufficient to reduce viruses in the space 5. Therefore, it is determined that the infectivity of viruses such as influenza viruses is high. In this case, step S523 is performed to determine the airflow rate (notch) A of the second fan 51 so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example).

[0248] [Set the air volume so that the virus infectivity ventilation rate is equal to or greater than the specified number of times] Next, in the first cleaning step S52 of this embodiment, the air volume (notch) A of the second fan 51 is determined so that the virus infectivity ventilation rate F is equal to or greater than the above rate (5 times / h in this example) (step S523).

[0249] In this embodiment, for example, from among the multiple second relationships R2 shown in FIG. 17, a second relationship R2c is identified that has a relative humidity H (e.g., 25% RH) that is the same as or closest to the relative humidity in the current space 5. Then, in the identified second relationship R2c, a fan airflow rate A (a combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) at which the virus infectivity air change rate F is equal to or greater than the above number (5 times / h in this example) can be identified. Furthermore, from the intersection of the identified second relationship R2c and the above number of virus infectivity air changes F (5 times / h in this example), a fan airflow rate A (a combination of the airflow rate of the first fan 16 and the airflow rate of the second fan 51) that can make the virus infectivity air change rate F equal to or greater than the above number can be identified. Then, the airflow rate of the second fan 51 included in this identified combination can be determined as the airflow rate (notch) A of the second fan 51 at which the virus infectivity air change rate F can be equal to or greater than the above number (5 times / h in this example).

[0250] [Set fan speed to determined speed] Next, in the first cleaning step S52 of this embodiment, the determined air volume A is set for the second fan 51 (step S524). In this embodiment, the air volume (notch) A of the second fan 51 is determined based on the relationship R between the relative humidity H, the virus infectivity ventilation rate F, and the fan air volume A (the combination of the air volumes of the first fan 16 and the second fan 51) so that the virus infectivity ventilation rate F is equal to or greater than the above number (5 times / h in this example). Setting such air volume A for the second fan 51 makes it possible to reliably reduce the infectivity of viruses in the space 5. Therefore, the reduction method of this embodiment makes it possible to more effectively combat infectious viruses without worsening the indoor environment.

[0251] As described above, in the reduction method of this embodiment, the air volumes of first fan 16 and second fan 51 are respectively determined based on the relationship R between relative humidity, virus infectivity ventilation rate, and fan air volume (the combination of the air volumes of first fan 16 and second fan 51) so that the virus infectivity ventilation rate is equal to or greater than the above number (5 times / h). As a result, in this embodiment, it is possible to expect a greater effect in preventing infectious viruses without worsening the indoor environment.

[0252] [Virus Reduction System (Fourth Embodiment)] In the reduction system 4 of the above-described embodiments, as shown in Fig. 13, a configuration including a ventilation fan (first fan) 16 and a cleaning second fan 51 has been exemplified, but the present invention is not limited to such a configuration. Fig. 18 is a cross-sectional view conceptually illustrating an example of a house 1 according to yet another embodiment of the present invention.

[0253] In the reduction system 4 of this embodiment, the first fan 16 is operated to perform a ventilation process in which the space air Ai is replaced and ventilated, and a cleaning process in which the space air Ai is supplied to the filter 52 and filtered. This makes it possible to omit the second fan 51 shown in FIG. 14, and the running costs of the reduction system 4 can be reduced.

[0254] The first fan 16 is for pressurizing (supplying) air (in this example, air including outside air Ao via the air flow Af) into the space 5. In this embodiment, the operation of the first fan 16 can be controlled by the control device 17. The first fan 16 in this embodiment is disposed inside the chamber 22, but is not particularly limited thereto, and may be disposed, for example, outside the chamber 22. The first fan 16 is controlled in multiple stages, as in the previous embodiments.

[0255] [Chamber] The chamber 22 in this embodiment is formed in a box shape having an internal space. The chamber 22 is disposed in the above-floor space 2, but is not particularly limited thereto, and may be disposed in the under-floor space 3, for example.

[0256] In this embodiment, the chamber 22 is formed with an air vent 23 that allows air to pass between its interior and the above-floor space 2 (space 5). In addition, a first duct 24 and a second duct 25 are connected to the chamber 22.

[0257] The first duct 24 in this embodiment is for connecting the chamber 22 and the above-floor space 2 (space 5). One end of the first duct 24 is connected to the chamber 22. The other end of the first duct 24 is connected to the above-floor space 2. In this embodiment, a first fan 16 is connected to the first duct 24. By operating the first fan 16, air inside the chamber 22 is sucked into the first duct 24, and an air flow Af can be generated in the chamber 22 and the first duct 24. The air inside the chamber 22 sucked into the first duct 24 (air flow Af) can be supplied to the above-floor space 2.

[0258] The second duct 25 in this embodiment is for connecting the chamber 22 and the underfloor space 3. One end of the second duct 25 is connected to the chamber 22. The other end of the second duct 25 is connected to the underfloor space 3.

[0259] In this embodiment, the second duct 25 is provided with an outside air supply fan 18. This outside air supply fan 18 is for pressurizing and sending outside air Ao (underfloor air Au) for ventilation to the chamber 22 via the second duct 25. In this embodiment, the operation of the outside air supply fan 18 can be controlled by the control device 17. The outside air Ao is introduced into the underfloor space 3 from the outside air inlet 13.

[0260] The filter 52 in this embodiment is disposed inside the chamber 22 and is provided upstream of the first fan 16 in the flow direction of the airflow Af. This allows the air, purified by capturing fine particles (including viruses) on the filter 52, to be supplied to the space 5 (above-floor space 2) through the first duct 24.

[0261] The indoor unit 19a in this embodiment is provided inside the chamber 22 and is arranged upstream of the filter 52 in the flow direction of the airflow Af. This indoor unit 19a takes in at least a portion of a mixture containing space air (return air circulated through the above-floor space 2) Ai that has circulated through the space 5 and under-floor air Au (outside air Ao). Meanwhile, conditioned air Ac that has been conditioned by the heat exchanger is discharged from the indoor unit 19a. As a result, conditioned air Ac can be generated inside the chamber 22.

[0262] [Space ventilation and air purification] In the reduction system 4 of this embodiment, an airflow Af is generated in the chamber 22 and the first duct 24 by operating the first fan 16. This airflow Af contains a mixture of space air Ai and underfloor air Au (outdoor air Ao), and conditioned air Ac resulting from heat exchange with the mixture in the indoor unit 19a. Furthermore, the airflow Af (including the conditioned air Ac and the mixture) passes through a filter 52, thereby capturing fine particles (including viruses) contained in the airflow Af. This allows the airflow Af to be purified.

[0263] The air flow Af purified by the filter 52 is supplied to the space 5 (above-floor space 2) through the first duct 24. Then, air (return air) Ai circulated through the space 5 can be collected in the chamber 22. Also, a portion of the space air Ai is exhausted to the outdoors 27, for example, via the exhaust port 26 and the exhaust fan 21. The exhaust fan 21 can be controlled by the control device 17.

[0264] In this manner, in the reduction system 4 of this embodiment, by operating the first fan 16, the outside air Ao (underfloor air Au) is supplied to the space 5, and the space air Ai is exhausted to the outdoors 27. This allows the space air Ai to be replaced, and the space 5 (above-floor space 2) to be ventilated.

[0265] Furthermore, in the reduction system 4 of this embodiment, by operating the first fan 16, the space air Ai is filtered by the filter 52, and the filtered space air Ai is supplied to the space 5. This purifies the space air Ai.

[0266] In this manner, in the reduction system 4 of this embodiment, the first fan 16 is operated to ventilate the space 5 and purify the space air Ai. Therefore, the particles (including viruses) floating in the space air Ai can be collected while being discharged to the outdoors 27. As a result, in the reduction system 4 of this embodiment, the particles floating in the space air Ai are further reduced, enabling further reduction of viruses.

[0267] [Virus reduction method (fourth embodiment)] In the reduction method (reduction system 4) of this embodiment, the airflow rate (notch) of the first fan 16 is controlled according to the relative humidity of the space 5 based on the processing procedures shown in Figures 3 and 4. This makes it possible to maintain low viral infectivity without excessively humidifying the space 5 or constantly operating the first fan 16 at a high airflow rate. Note that in this embodiment, by performing the ventilation step S2 shown in Figures 3 and 4, not only ventilation is performed by replacing the space air Ai, but also purification is performed by supplying the space air Ai to the filter 52 and filtering it. Therefore, the ventilation step S2 (including the first ventilation step S22) also serves as a purification step (including the first purification step).

[0268] 5, in the first ventilation step (first cleaning step) S22 of this embodiment, the air volume (notch) of the first fan 16 is increased in stages in accordance with a decrease in the relative humidity of the space 5. As a result, in the first ventilation step (first cleaning step) S22 of this embodiment, the air volume (notch) of the first fan 16 can be set to achieve a good balance between a reduction in viruses (reduction in infectivity) and a reduction in noise and power consumption.

[0269] [Virus reduction method (another example of the fourth embodiment)] In the first ventilation step (first cleaning step) S22 of this embodiment, the air volume (notch) of first fan 16 is determined based on a previously prepared relationship between the relative humidity, the virus infectivity titer air change rate, and the air volume (notch) of first fan 16 so that the virus infectivity titer air change rate is equal to or greater than a predetermined number. In this case, prior to the ventilation step (cleaning step) S2, it is preferable to perform the relationship acquisition step (relationship acquisition method) shown in Fig. 6 to acquire the first relationship R1 shown in Fig. 7 and the second relationship R2 shown in Fig. 8. The procedure for acquiring the first relationship R1 and the second relationship R2 is as described above.

[0270] In the first ventilation step (first cleaning step) S22 of this embodiment, as in the previous embodiments, the airflow rate (notch) of the first fan 16 is increased as the relative humidity of the space 5 decreases. The airflow rate (notch) of the first fan 16 is determined based on the relationship R obtained in the relationship acquisition step (relationship acquisition method) so that the virus infectivity ventilation frequency F is equal to or greater than the above frequency (5 times / h in this example).

[0271] In the first ventilation step (first cleaning step) S22 of this embodiment, step S221 is performed to identify the virus infectivity air change rate F in the current space 5 based on the processing procedure shown in FIG. 9 . Furthermore, step S222 is performed to determine whether the virus infectivity air change rate F in the current space 5 is equal to or greater than the aforementioned rate (5 times / h in this example). At this time, if the virus infectivity air change rate F is less than the aforementioned rate ("No" in step S222), step S223 is performed to determine the air volume (notch) A of the first fan 16 so that the virus infectivity air change rate F is equal to or greater than the aforementioned rate. Then, step S224 is performed to set the determined air volume A to the first fan 16. As a result, the reduction method of this embodiment can reliably reduce the infectivity of viruses in the space 5, making it possible to more effectively combat infectious viruses without worsening the indoor environment.

[0272] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified and implemented in various ways.

[0273] [Note] The present invention includes the following aspects.

[0274] [Invention 1] A method for reducing viruses floating in space, comprising: measuring the relative humidity of the space; a ventilation step of replacing and ventilating the space by operating a fan, The ventilation step includes a first ventilation step in which the air volume of the fan is increased as the relative humidity becomes lower. Virus reduction methods. [Invention 2] A method for reducing viruses floating in space, comprising: measuring the relative humidity of the space; a cleaning step of supplying the air in the space to a filter and filtering it by operating a fan; The cleaning step includes a first cleaning step in which the air volume of the fan is increased as the relative humidity becomes lower. Virus reduction methods. [Invention 3] A method for reducing viruses floating in space, comprising: measuring the relative humidity of the space; a ventilation step of replacing and ventilating the space by operating a first fan; a cleaning step of supplying air in the space to a filter and filtering the air by operating the first fan or a second fan different from the first fan, the ventilation step includes a first ventilation step of increasing the air volume of the first fan as the relative humidity becomes lower, the cleaning step includes a first cleaning step in which the air volume of the first fan or the second fan is increased as the relative humidity becomes lower. Virus reduction methods. [Invention 4] The virus reduction method according to Invention 1, wherein the first ventilation step increases the air volume stepwise in accordance with the decrease in the relative humidity. [Invention 5] 3. The virus reduction method according to claim 2, wherein the first cleaning step increases the air volume stepwise in accordance with the decrease in the relative humidity. [Invention 6] The first ventilation step includes increasing the air volume stepwise in accordance with the decrease in the relative humidity, The virus reduction method according to Invention 3, wherein the first cleaning step increases the air volume stepwise in accordance with the decrease in the relative humidity. [Invention 7] 7. The method for reducing viruses according to any one of claims 1 to 6, further comprising the step of conditioning the air in the space with an air conditioner. [Invention 8] 8. The method for reducing a virus according to any one of claims 1 to 7, wherein the virus includes an influenza virus. [Invention 9] The virus reduction method according to any one of Inventions 1 to 8, wherein the air volume is determined based on a predetermined relationship between relative humidity, virus infectivity air change rate, and air volume of the fan so that the virus infectivity air change rate is equal to or greater than a predetermined number. [Invention 10] further comprising a relation obtaining step of obtaining the relation; The relationship acquisition step includes: a first step of determining the decay over time of the infectivity titer of the airborne virus under a plurality of conditions correlating the air volume and the relative humidity of the air; A second step of determining the virus infectivity titer and ventilation rate for the plurality of conditions based on the results of the first step; identifying the relationship based on the result of the second step; 10. The method for reducing a virus according to claim 9, comprising: [Invention 11] The virus reduction method according to invention 10, wherein the relationship includes a first relationship between the relative humidity of the air and the virus infectivity / air change rate, specified for each air volume. [Invention 12] 12. The method for reducing viruses according to claim 10 or 11, wherein the relationship includes a second relationship between the air volume and the virus infectivity titer / air change rate, which is specified for each relative humidity of the air. [Invention 13] 13. The method for reducing a virus according to any one of claims 9 to 12, wherein the number of times is 5 times / h or more. [Invention 14] A system for reducing viruses floating in space, comprising: a humidity sensor for measuring the relative humidity of the space; With fans, a control device that operates the fan to replace and ventilate the air in the space, The control device includes a first ventilation unit that increases the air volume of the fan as the relative humidity decreases. Virus reduction system. [Invention 15] A system for reducing viruses floating in space, comprising: a humidity sensor for measuring the relative humidity of the space; With fans, a control device that operates the fan to supply air in the space to a filter and filter it; The control device includes a first cleaning unit that increases the airflow rate of the fan as the relative humidity decreases. Virus reduction system. [Invention 16] A system for reducing viruses floating in space, comprising: a humidity sensor for measuring the relative humidity of the space; a first fan and / or a second fan; a control device; The control device a ventilation unit that operates the first fan to replace and ventilate the air in the space; a purifying unit that supplies air in the space to a filter and filters it by operating the first fan or a second fan different from the first fan, the ventilation unit includes a first ventilation unit that increases the airflow rate of the first fan as the relative humidity decreases, the purifying unit includes a first purifying unit that increases the airflow rate of the first fan or the second fan as the relative humidity decreases. Virus reduction system. [Invention 17] 15. A virus reduction system according to claim 14, wherein the first ventilation section increases the airflow volume in stages in accordance with the decrease in the relative humidity. [Invention 18] 16. A virus reduction system according to claim 15, wherein the first purification section increases the airflow volume in stages in accordance with the decrease in the relative humidity. [Invention 19] the first ventilation section increases the airflow rate in stages in response to the decrease in the relative humidity, 17. A virus reduction system according to claim 16, wherein the first purification section increases the airflow volume in stages in accordance with the decrease in the relative humidity. [Invention 20] 20. A virus reduction system according to any one of claims 14 to 19, further comprising an air conditioner for conditioning the air. [Invention 21] 21. A virus reduction system according to any one of claims 14 to 20, wherein the virus includes influenza virus. [Invention 22] 22. A virus reduction system according to any one of claims 14 to 21, wherein the air volume is determined based on a previously prepared relationship between relative humidity, virus infectivity titer air change rate, and air volume of the fan so that the virus infectivity titer air change rate is equal to or greater than a predetermined rate. [Invention 23] the control device includes a relationship acquisition unit that determines the relationship; The relationship acquisition unit a first determination unit that determines the decay over time of the infectivity titer of the airborne viruses under a plurality of conditions that correlate the air volume and the relative humidity of the air; a second identification unit that identifies the virus infectivity titer and ventilation rate for the plurality of conditions based on the results identified in the first identification unit; a third identification unit that identifies the relationship from the result identified by the second identification unit; 23. A virus reduction system according to claim 22, comprising: [Invention 24] 24. A virus reduction system according to claim 23, wherein the relationship includes a first relationship between the relative humidity of the air and the virus infectivity ventilation rate, specified for each air volume. [Invention 25] 25. A virus reduction system according to invention 23 or 24, wherein the relationship includes a second relationship between the air volume and the virus infectivity ventilation rate, specified for each relative humidity of the air. [Invention 26] 26. A virus reduction system according to any one of claims 22 to 25, wherein the frequency is 5 times / h or more. [Explanation of symbols]

[0275] 5 Space 16 Fans Ai Air

Claims

1. A method for reducing viruses floating in space, comprising: measuring the relative humidity of the space; a ventilation step of replacing and ventilating the space by operating a fan, The ventilation step includes a first ventilation step of increasing the air volume of the fan as the relative humidity becomes lower. Virus reduction methods.

2. A method for reducing viruses floating in space, comprising: measuring the relative humidity of the space; a cleaning step of supplying the air in the space to a filter and filtering it by operating a fan; The cleaning step includes a first cleaning step in which the air volume of the fan is increased as the relative humidity becomes lower. Virus reduction methods.

3. A method for reducing viruses floating in space, comprising: measuring the relative humidity of the space; a ventilation step of replacing and ventilating the space by operating a first fan; a cleaning step of supplying air in the space to a filter and filtering the air by operating the first fan or a second fan different from the first fan, the ventilation step includes a first ventilation step of increasing the air volume of the first fan as the relative humidity decreases, the cleaning step includes a first cleaning step of increasing the air volume of the first fan or the second fan as the relative humidity becomes lower. Virus reduction methods.

4. The virus reduction method according to claim 1 , wherein the first ventilation step increases the air volume in stages in accordance with the decrease in the relative humidity.

5. The virus reduction method according to claim 2 , wherein the first cleaning step increases the airflow rate in stages according to the decrease in the relative humidity.

6. the first ventilation step includes increasing the air volume stepwise in accordance with the decrease in the relative humidity, The virus reduction method according to claim 3 , wherein the first cleaning step increases the airflow rate in stages according to the decrease in the relative humidity.

7. The virus reduction method according to claim 1 , further comprising the step of conditioning the air in the space with an air conditioner.

8. The method for reducing a virus according to claim 1 , wherein the virus includes an influenza virus.

9. 4. The virus reduction method according to claim 1, wherein the air volume is determined based on a predetermined relationship between the relative humidity, the virus infectivity titer air change rate, and the air volume of the fan, so that the virus infectivity titer air change rate is equal to or greater than a predetermined number.

10. further comprising a relation obtaining step of obtaining the relation; The relationship acquisition step includes: a first step of determining the decay over time of the infectivity titer of the airborne viruses under a plurality of conditions correlating the air volume and the relative humidity of the air; A second step of identifying the virus infectivity titer and ventilation rate for the plurality of conditions based on the results of the first step; identifying the relationship based on the result of the second step; The method for reducing viruses according to claim 9, comprising:

11. The virus reduction method according to claim 10 , wherein the relationship includes a first relationship between the relative humidity of the air and the virus infectivity ventilation rate, which is specified for each air volume.

12. The virus reduction method according to claim 10 , wherein the relationship includes a second relationship between the air volume and the virus infectivity ventilation rate, which is specified for each relative humidity of the air.

13. The virus reduction method according to claim 9, wherein the number of times is 5 times / h or more.

14. A system for reducing viruses floating in space, comprising: a humidity sensor for measuring the relative humidity of the space; With fans, a control device that operates the fan to replace and ventilate the air in the space, the control device includes a first ventilation unit that increases the air volume of the fan as the relative humidity decreases, Virus reduction system.

15. A system for reducing viruses floating in space, comprising: a humidity sensor for measuring the relative humidity of the space; With fans, a control device that operates the fan to supply air in the space to a filter and filter it; The control device includes a first cleaning unit that increases the airflow rate of the fan as the relative humidity decreases. Virus reduction system.

16. A system for reducing viruses floating in space, comprising: a humidity sensor for measuring the relative humidity of the space; a first fan and / or a second fan; a control device; The control device a ventilation unit that operates the first fan to replace and ventilate the air in the space; a purifying unit that supplies air in the space to a filter and filters it by operating the first fan or a second fan different from the first fan, the ventilation unit includes a first ventilation unit that increases the airflow rate of the first fan as the relative humidity decreases, the purifying unit includes a first purifying unit that increases the air volume of the first fan or the second fan as the relative humidity decreases. Virus reduction system.

17. The virus reduction system according to claim 14 , wherein the first ventilation section increases the airflow rate in stages in response to a decrease in the relative humidity.

18. The virus reduction system according to claim 15 , wherein the first purification unit increases the airflow rate in stages in response to a decrease in the relative humidity.

19. the first ventilation unit increases the airflow rate in stages in response to the decrease in the relative humidity, The virus reduction system according to claim 16 , wherein the first purification unit increases the airflow rate in stages in response to a decrease in the relative humidity.

20. 17. The virus reduction system of claim 14, further comprising an air conditioner for conditioning the air.

21. 17. The virus reduction system of claim 14, wherein the virus comprises an influenza virus.

22. The virus reduction system according to any one of claims 14 to 16, wherein the air volume is determined based on a predetermined relationship between the relative humidity, the virus infectivity titer air change rate, and the air volume of the fan, so that the virus infectivity titer air change rate is equal to or greater than a predetermined number.

23. the control device includes a relationship acquisition unit that determines the relationship; The relationship acquisition unit a first determination unit that determines the decay over time of the infectivity titer of the airborne viruses under a plurality of conditions that correlate the air volume and the relative humidity of the air; a second identification unit that identifies the virus infectivity and ventilation rate for the plurality of conditions based on the results identified by the first identification unit; a third identification unit that identifies the relationship from the result identified by the second identification unit; 23. The virus reduction system of claim 22, comprising:

24. The virus reduction system of claim 23, wherein the relationship includes a first relationship between the relative humidity of the air and the virus infectivity ventilation rate, specified for each air volume.

25. The virus reduction system of claim 23, wherein the relationship includes a second relationship between the air volume and the virus infectivity ventilation rate, specified for each relative humidity of the air.

26. The virus reduction system of claim 22, wherein the frequency is 5 times / h or more.

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