Ventilation control device and ventilation control method

Abstract

To provide a ventilation control device capable of separating VOC concentration derived from building material or the like defining and forming an indoor space from TVOC concentration of the indoor space.SOLUTION: A ventilation control device 20 includes: a TVOC acquiring unit 21 for acquiring TVOC concentration; a CO2 acquiring unit 22 for acquiring CO2 concentration; a room-staying person acquiring unit 23 for acquiring room-staying person information related to presence / absence of a person staying in the room; and a TVOC determination unit 24 for determining whether or not the acquired TVOC concentration includes VOC concentration derived from building material or the like defining and forming an indoor space on the basis of the TVOC concentration, the CO2 concentration, and the room-staying person information, and controlling a ventilation control unit 25 and a display control unit 26 on the basis of the determination result.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a ventilation control device and a ventilation control method. [Background technology]

[0002] Conventionally, technologies for improving the air quality of indoor spaces have been provided. For example, Patent Document 1 discloses a ventilation control technology for ventilating an indoor space based on the concentration of TVOCs (Total Volatile Organic Compounds) contained in the air in the indoor space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-85714 Summary of the Invention [Problem to be solved by the invention]

[0004] TVOCs are composed of VOCs derived from human breath and VOCs derived from building materials that define indoor spaces. VOCs derived from building materials that define indoor spaces may have adverse effects on the human body.

[0005] The ventilation control technology disclosed in Patent Document 1 only detects TVOC concentrations and does not distinguish between VOCs derived from human breath and VOCs derived from building materials that define an indoor space. For this reason, the ventilation control technology disclosed in Patent Document 1 cannot distinguish the VOC concentration derived from building materials that define an indoor space from the TVOC concentration in the indoor space.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a ventilation control device that can separate the VOC concentration derived from building materials that divide and form an indoor space from the TVOC concentration in the indoor space. [Means for solving the problem]

[0007] The ventilation control device according to the present disclosure includes a TVOC acquisition unit that acquires the TVOC concentration from a TVOC sensor that measures the TVOC concentration in the indoor space, a CO2 acquisition unit that acquires the CO2 concentration from a CO2 sensor that measures the CO2 concentration in the indoor space, an occupant acquisition unit that acquires occupant information regarding the presence or absence of occupants from an occupant detection unit that detects the presence or absence of occupants in the indoor space, a ventilation control unit that determines whether the acquired TVOC concentration includes a concentration of VOCs derived from the building materials that define the indoor space based on the TVOC concentration acquired by the TVOC acquisition unit, the CO2 concentration acquired by the CO2 acquisition unit, and the occupant information acquired by the occupant acquisition unit, and controls the ventilation unit that ventilates the indoor space based on the determination result, and a display control unit that controls a display unit that displays an alert, among which a TVOC determination unit that operates at least the ventilation control unit. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to separate the VOC concentration derived from building materials that divide and form an indoor space from the TVOC concentration in the indoor space. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing the configuration of a ventilation system to which a ventilation control device according to a first embodiment is applied. [Figure 2] FIG. 10 is a graph showing the transition of CO2 concentration after people have left the indoor space. [Figure 3] 3A to 3C are diagrams showing correlation coefficients between the measurement items in offices 1 to 3, which are indoor spaces. [Figure 4]4A to 4C are diagrams showing the results of cluster analysis of each measurement item in offices 1 to 3, which are indoor spaces. [Figure 5] 5A and 5B are graphs showing how CO2 concentration and TVOC concentration are linked. Fig. 5A shows the time trends of CO2 concentration and TVOC concentration. Fig. 5B shows the time derivative of the square of the difference between the standardized CO2 concentration and TVOC concentration. [Figure 6] 3 is a flowchart showing a ventilation control method according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0011] Embodiment 1 A ventilation control device 20 according to a first embodiment will be described with reference to FIGS. 1 to 6. FIG.

[0012] First, the configuration of a ventilation control device 20 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of a ventilation system to which the ventilation control device 20 according to the first embodiment is applied.

[0013] As shown in FIG. 1, the ventilation system according to the first embodiment includes a TVOC sensor 11, a CO2 sensor 12, an occupant detection unit 13, a ventilation control device 20, a ventilation unit 31, and a display unit 32.

[0014] The TVOC sensor 11 is installed, for example, inside an indoor space that is a target space. The TVOC sensor 11 measures the concentration of TVOCs contained in the air in the indoor space. The TVOC sensor 11 transmits a signal related to the measured TVOC concentration to the ventilation control device 20.

[0015] The CO2 sensor 12 is provided, for example, inside the indoor space. The CO2 sensor 12 measures the concentration of CO2 (carbon dioxide) contained in the air in the indoor space. The CO2 sensor 12 transmits a signal related to the measured CO2 concentration to the ventilation control device 20.

[0016] The occupancy detection unit 13 detects whether or not there are people in the indoor space. If there are people in the indoor space, the occupancy detection unit 13 may also detect the number of people. The occupancy detection unit 13 transmits occupancy information regarding the presence or absence of people and the number of people to the ventilation control device 20.

[0017] The occupant detection unit 13 is, for example, an entry / exit management system. This entry / exit management system is a system that uses an IC card given to each individual to identify the people who have entered or exited an indoor space and the number of people. The occupant detection unit 13 is, for example, a sensor such as an infrared sensor or an image sensor. In this case, the occupant detection unit 13 is installed in the indoor space, and can detect the presence or absence of people in the indoor space and the number of people.

[0018] The ventilation control device 20 receives a signal related to the TVOC concentration from the TVOC sensor 11. The ventilation control device 20 also receives a signal related to the CO2 concentration from the CO2 sensor 12. The ventilation control device 20 further receives occupancy information from the occupancy detection unit 13. Based on the TVOC concentration, CO2 concentration, and occupancy information, the ventilation control device 20 determines whether the acquired TVOC concentration includes a concentration of VOCs derived from building materials that define the indoor space. Next, based on the determination result, the ventilation control device 20 controls at least the ventilation unit 31 out of the ventilation unit 31 and the display unit 32, which will be described later.

[0019] The ventilation unit 31 receives a ventilation control signal from the ventilation control device 20. Upon receiving the ventilation control signal, the ventilation unit 31 ventilates the indoor space. For example, the ventilation unit 31 is composed of an air supply device that supplies air from the outdoor space to the indoor space, an exhaust device that exhausts air from the indoor space to the outdoor space, and an air filter. Therefore, the ventilation unit 31 filters the air taken in from the outdoor space by passing it through the air filter, and allows the air to flow into the indoor space, while also allowing the air in the indoor space to flow out to the outdoor space. Note that the ventilation unit 31 may be an air conditioner.

[0020] The display unit 32 receives a display control signal from the ventilation control device 20. Upon receiving the display control signal, the display unit 32 displays an alert. The alert displayed by the display unit 32 is an alarm or message calling for ventilation.

[0021] Here, the ventilation control device 20 has a TVOC acquisition unit 21, a CO2 acquisition unit 22, an occupant acquisition unit 23, a TVOC determination unit 24, a ventilation control unit 25, and a display control unit .

[0022] The TVOC acquisition unit 21 acquires a signal relating to the TVOC concentration from the TVOC sensor 11. The TVOC acquisition unit 21 transmits the signal relating to the TVOC concentration acquired from the TVOC sensor 11 to the TVOC determination unit 24.

[0023] The CO2 acquisition unit 22 acquires a signal relating to the CO2 concentration from the CO2 sensor 12. The CO2 acquisition unit 22 transmits the signal relating to the CO2 concentration acquired from the CO2 sensor 12 to the TVOC determination unit 24.

[0024] The occupant acquisition unit 23 acquires occupant information from the occupant detection unit 13. The occupant acquisition unit 23 transmits the occupant information acquired from the occupant detection unit 13 to the TVOC determination unit 24.

[0025] When no one is present in the indoor space, the TVOC determination unit 24 determines whether human breath remains in the indoor space based on the transition of the CO2 concentration. Next, when the TVOC determination unit 24 determines that human breath remains in the indoor space, it transmits a signal related to ventilation to the ventilation control unit 25.

[0026] In response to this, the ventilation control unit 25 sends a ventilation control signal to the ventilation unit 31, which then ventilates the indoor space. This reduces the CO2 concentration in the indoor space. As a result, the air in the indoor space does not contain human exhaled breath.

[0027] Next, when the air in the indoor space becomes air that does not contain human exhaled breath, the TVOC determination unit 24 acquires the TVOC concentration and estimates the acquired TVOC concentration as the concentration of VOCs derived from building materials that define the indoor space.

[0028] At this time, when the TVOC determination unit 24 acquires the TVOC concentration (the concentration of VOCs derived from building materials that divide the indoor space, etc.), if the TVOC concentration is equal to or greater than a predetermined regulatory value, it sends a signal regarding ventilation to the ventilation control unit 25 and a signal regarding display to the display control unit 26.

[0029] In response to this, the ventilation control unit 25 sends a ventilation control signal to the ventilation unit 31, causing the ventilation unit 31 to ventilate the indoor space. Furthermore, the display control unit 26 sends a display control signal to the display unit 32, causing the display unit 32 to display an alert. Note that ventilation by the ventilation unit 31 and display of the alert by the display unit 32 continue until the TVOC concentration falls below the regulated value.

[0030] Next, the above-mentioned series of operations when no one is present in the indoor space will be explained using Figure 2. Figure 2 is a diagram showing the transition of CO2 concentration after no one is present in the indoor space. Figure 2 is an example showing the transition of CO2 concentration in an office, which is an indoor space, from evening to morning.

[0031] The vertical axis on the left in Figure 2 represents the CO2 concentration in the indoor space. The vertical axis on the right in Figure 2 represents the TMP (temperature) and HUM (humidity) in the indoor space. The horizontal axis in Figure 2 represents the passage of time. In Figure 2, the solid line represents the CO2 concentration, the two-dot chain line represents the HUM, and the dashed line represents the TMP.

[0032] For example, at time t1 (around 180 minutes), the ventilation unit 31 is stopped.

[0033] Next, at time t2 (around 250 min), the ventilation unit 31 is stopped, causing the CO2 concentration to rise. Based on the change in CO2 concentration, the TVOC determination unit 24 determines that human exhaled breath remains in the office.

[0034] Next, at time t3 (around 350 min), the CO2 concentration reaches its highest. After this time t3, the CO2 concentration gradually decreases. This is thought to be because when people leave the office to finish work, the CO2 diffuses and its concentration gradually decreases.

[0035] Next, at time t4 (around 950 min), when the ventilation unit 31 starts operating before work starts, the CO2 concentration drops rapidly.

[0036] Next, at time t5 (around 1000 min), the air in the office becomes steady-state air that does not contain human exhaled breath. When the air in the office becomes air that does not contain human exhaled breath, the TVOC determination unit 24 acquires the TVOC concentration. The TVOC determination unit 24 also estimates the acquired TVOC concentration as the concentration of VOCs derived from building materials that define the office.

[0037] Next, at time t6 (around 1050 min), people start coming into the office, and the CO2 concentration starts to gradually increase.

[0038] On the other hand, when there is a person in the indoor space, the TVOC determination unit 24 determines whether the TVOC concentration includes a VOC concentration based on the transitions in the CO2 concentration and the TVOC concentration. That is, the TVOC determination unit 24 determines whether the air in the indoor space includes VOCs derived from building materials that define the indoor space based on the transitions in the CO2 concentration and the TVOC concentration.

[0039] Specifically, because there is a correlation between the CO2 concentration and the TVOC concentration, the TVOC determination unit 24 determines that the TVOC concentration contains a VOC concentration when the deviation value between the CO2 concentration and the TVOC concentration is equal to or greater than a predetermined value. That is, the TVOC determination unit 24 determines that the air in the indoor space contains VOCs derived from building materials that define the indoor space.

[0040] Next, TVOC determination unit 24 transmits a signal related to ventilation to ventilation control unit 25, and transmits a signal related to display to display control unit 26.

[0041] In response to this, the ventilation control unit 25 sends a ventilation control signal to the ventilation unit 31, causing the ventilation unit 31 to ventilate the indoor space. Furthermore, the display control unit 26 sends a display control signal to the display unit 32, causing the display unit 32 to display an alert. Note that ventilation by the ventilation unit 31 and display of the alert by the display unit 32 continue until the TVOC determination unit 24 determines that the air in the indoor space does not contain VOCs derived from building materials that define the indoor space.

[0042] Next, the correlation between CO2 concentration and TVOC concentration will be explained with reference to FIGS. 3 to 5.

[0043] 3A to 3C in Fig. 3 show the correlation coefficients between each measurement item in the indoor spaces of Office 1 to Office 3. The measurement items are, for example, IEQ (Indoor Environmental Quality: indoor air quality), CO2, TVOC, PM (suspended particulate matter), PMV (predicted mean thermal sensation report), and occupants (number of people in the room). The numerical values ​​in Fig. 3A to 3C indicate the correlation coefficients between each measurement item.

[0044] Here, for example, a human being has a height of 5.5 m. 3 In a chamber, the dose was 10-100μg / m per person for approximately one hour at rest. 3 It has been reported that it emits TVOCs (equivalent to 2.7 to 27 ppb of toluene). In addition, for example, when analyzing the above measurement items reported in a paper by Kim, J. et al. (Building and Environment, 156, 99-109, (2019)), the correlation coefficients shown in Figures 3A to 3C were obtained.

[0045] As shown in Figure 3A, the correlation coefficient between CO2 and TVOC is 0.92828, the correlation coefficient between Occupants and CO2 is 0.97365, and the correlation coefficient between Occupants and TVOC is 0.94731. These three correlation coefficients are much larger than the other correlation coefficients.

[0046] As shown in Figure 3B, the correlation coefficient between CO2 and TVOC is 9.99001, the correlation coefficient between Occupants and CO2 is 0.85658, and the correlation coefficient between Occupants and TVOC is 0.82042. These three correlation coefficients are much larger than the other correlation coefficients.

[0047] As shown in Figure 3C, the correlation coefficient between CO2 and TVOC is 0.79546, the correlation coefficient between Occupants and CO2 is 0.9935, and the correlation coefficient between Occupants and TVOC is 0.77744. These three correlation coefficients are much larger than the other correlation coefficients.

[0048] Therefore, as is clear from FIGS. 3A to 3C, it can be easily understood that CO2, TVOC, and occupants are correlated with each other.

[0049] 4A to 4C in Fig. 4 show the results of cluster analysis of each measurement item in the indoor spaces of Office 1 to Office 3. As shown in Fig. 4A to 4C, CO2, TVOC, and occupants belong to the same hierarchical level. Therefore, as is clear from Fig. 4A to 4C, it is easy to see that CO2, TVOC, and occupants are correlated with each other.

[0050] 3 and 4, it can be seen that when there are people in an indoor space, the CO2 concentration and the TVOC concentration are linked. Therefore, if this link is broken, it can be determined that VOCs other than those derived from human breath, i.e., VOCs derived from building materials that define the indoor space, have flowed into the indoor space.

[0051] Furthermore, whether or not the linkage between the CO2 concentration and the TVOC concentration has been broken can be determined using the following equations (1) to (3). Zc = (C - Cm) / Csd (1) Zv = (V - Vm) / Vsd (2) D = (Zc - Zv) 2 ···(3) C:CO2 concentration Cm: Average CO2 concentration per unit time Csd: Standard deviation of CO2 concentration per unit time V:TVOC concentration Vm: Average value of TVOC concentration per unit time Vsd: Standard deviation of TVOC per unit time

[0052] FIG. 5A is a diagram showing changes over time in CO2 concentration and TVOC concentration. The vertical axis on the left side of FIG. 5A represents the CO2 concentration in the indoor space. The vertical axis on the right side of FIG. 5A represents the TVOC concentration in the indoor space. The horizontal axis in FIG. 5A represents the passage of time. In addition, the solid line in FIG. 5A represents the TVOC concentration, the two-dot chain line represents a state in which the TVOC concentration deviates from the correlation with the CO2 concentration, and the dashed line represents the CO2 concentration.

[0053] FIG. 5B shows the transition of the time derivative with respect to "D" calculated by equation (3). The vertical axis of FIG. 5B represents the magnitude of the time derivative with respect to "D". The horizontal axis of FIG. 5B represents the passage of time. The solid line in FIG. 5B represents a state in which the TVOC concentration is correlated with the CO2 concentration, and the two-dot chain line represents a state in which the TVOC concentration deviates from the correlation with the CO2 concentration.

[0054] As shown in FIGS. 5A and 5B, as described above, by using equations (1) to (3), it is possible to determine whether the link between the CO2 concentration and the TVOC concentration has been broken.

[0055] Next, the ventilation control method according to the first embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the ventilation control method according to the first embodiment.

[0056] In step ST11, the TVOC sensor 11 starts measuring the TVOC concentration. In response to this, the TVOC acquisition unit 21 acquires the TVOC concentration and transmits the acquired TVOC concentration to the TVOC determination unit 24.

[0057] In step ST12, the CO2 sensor 12 starts measuring the CO2 concentration. In response to this, the CO2 acquisition unit 22 acquires the CO2 concentration and transmits the acquired CO2 concentration to the TVOC determination unit 24.

[0058] In step ST13, the occupant detection unit 13 starts detecting whether or not there is an occupant in the indoor space. In response to this, the occupant acquisition unit 23 acquires occupant information and transmits the acquired occupant information to the TVOC determination unit 24.

[0059] In step ST14, the TVOC determining unit 24 determines whether or not there is a person in the indoor space. If the TVOC determining unit 24 determines that there is no person in the indoor space (if NO), the ventilation control method proceeds to step ST15. On the other hand, if the TVOC determining unit 24 determines that there is a person in the indoor space (if YES), the ventilation control method proceeds to step ST21.

[0060] In step ST15, the TVOC determining unit 24 constantly monitors the transition of the CO2 concentration acquired by the CO2 acquiring unit 22.

[0061] In step ST16, the TVOC determination unit 24 determines whether human breath remains in the indoor space. If the TVOC determination unit 24 determines that human breath remains in the indoor space (YES), the ventilation control method proceeds to step ST17. On the other hand, if the TVOC determination unit 24 determines that human breath does not remain in the indoor space (NO), the ventilation control method proceeds to step ST18.

[0062] In step ST17, the ventilation control unit 25 controls the ventilation unit 31. Therefore, the ventilation unit 31 ventilates the indoor space. As a result, the air in the indoor space becomes air that does not contain human exhaled breath.

[0063] In step ST18, the TVOC determining unit 24 estimates the acquired TVOC concentration as the concentration of VOCs derived from building materials and the like that define the indoor space.

[0064] In step ST19, the TVOC determination unit 24 determines whether the acquired TVOC concentration is equal to or greater than a preset regulation value. If the TVOC determination unit 24 determines that the TVOC concentration is equal to or greater than the regulation value (YES), the ventilation control method proceeds to step ST20. On the other hand, if the TVOC determination unit 24 determines that the TVOC concentration is not equal to or greater than the regulation value (NO), the ventilation control method returns to step ST14.

[0065] In step ST20, the ventilation control unit 25 controls the ventilation unit 31. As a result, the ventilation unit 31 ventilates the indoor space. Furthermore, the display control unit 26 controls the display unit 32. As a result, the display unit 32 displays an alert. Then, the ventilation control method ends.

[0066] In step ST21, the TVOC determination unit 24 calculates the deviation between the transition of the TVOC concentration and the transition of the CO2 concentration.

[0067] In step ST22, the TVOC determination unit 24 determines whether or not there is a discrepancy in the correlation between the changes in TVOC concentration and the changes in CO2 concentration. If the TVOC determination unit 24 determines that there is a discrepancy (YES), the air in the indoor space contains VOCs derived from building materials that define the indoor space, and the ventilation control method proceeds to step ST23. On the other hand, if the TVOC determination unit 24 determines that there is no discrepancy (NO), the air in the indoor space does not contain VOCs derived from building materials that define the indoor space, and the ventilation control method returns to step ST14.

[0068] In step ST23, the TVOC determination unit 24 determines whether the deviation value between the CO2 concentration and the TVOC concentration is equal to or greater than a predetermined value. If the TVOC determination unit 24 determines that the deviation value is equal to or greater than the predetermined value, the ventilation control method proceeds to step ST20. On the other hand, if the TVOC determination unit 24 determines that the deviation value is not equal to or greater than the predetermined value, the air in the indoor space contains VOCs derived from building materials that define the indoor space, but the VOC concentration is at a level that does not adversely affect the human body, and the ventilation control method returns to step ST14.

[0069] As described above, the ventilation control device 20 according to the first embodiment includes a TVOC acquisition unit 21 that acquires the TVOC concentration from a TVOC sensor 11 that measures the TVOC concentration in the indoor space, a CO2 acquisition unit 22 that acquires the CO2 concentration from a CO2 sensor 12 that measures the CO2 concentration in the indoor space, an occupant acquisition unit 23 that acquires occupant information regarding the presence or absence of occupants from an occupant detection unit 13 that detects the presence or absence of occupants in the indoor space, a ventilation control unit 25 that determines whether the acquired TVOC concentration includes a concentration of VOCs derived from building materials that define the indoor space, based on the TVOC concentration acquired by the TVOC acquisition unit 21, the CO2 concentration acquired by the CO2 acquisition unit 22, and the occupant information acquired by the occupant acquisition unit 23, and controls a ventilation unit 31 that ventilates the indoor space based on the determination result, and a display control unit 26 that controls a display unit 32 that displays an alert. Of these, the ventilation control unit 25 is also equipped with a TVOC determination unit 24 that operates at least the ventilation control unit 25. Therefore, the ventilation control device 20 can separate the VOC concentration derived from the building materials that define the indoor space from the TVOC concentration in the indoor space.

[0070] It should be noted that, within the scope of the present disclosure, any of the components of the embodiments may be modified or omitted. [Explanation of symbols]

[0071] 11 TVOC sensor 12 CO2 sensor 13 Occupancy detection unit 20 Replacement control device 21 TVOC Acquisition Department 22 CO2 Acquisition Department 23. Acquisition Department for those in the same room 24 TVOC Determination Department 25 Replacement Control Department 26 represents the Ministry of Control 31 Replacement Department 32 Display unit

Claims

1. a TVOC acquisition unit that acquires a TVOC concentration from a TVOC sensor that measures a TVOC concentration in an indoor space; a CO2 acquisition unit that acquires a CO2 concentration from a CO2 sensor that measures a CO2 concentration in the indoor space; an occupant acquisition unit that acquires occupant information regarding the presence or absence of an occupant from an occupant detection unit that detects the presence or absence of an occupant in the indoor space; The device includes a ventilation control unit that controls a ventilation unit that ventilates the indoor space and a display control unit that controls a display unit that displays an alert, and a TVOC determination unit that determines whether or not the acquired TVOC concentration includes a concentration of VOCs derived from building materials that define the indoor space, based on the TVOC concentration acquired by the TVOC acquisition unit, the CO2 concentration acquired by the CO2 acquisition unit, and the occupant information acquired by the occupant acquisition unit. The device includes a ventilation control unit that controls a ventilation unit that ventilates the indoor space and a display control unit that controls a display unit that displays an alert, and a TVOC determination unit that operates at least the ventilation control unit. A ventilation control device characterized by:

2. The TVOC determination unit If no one is present in the indoor space, it is determined based on a transition of the CO2 concentration whether or not human exhaled breath remains in the indoor space; When determining that human exhaled air remains in the indoor space, a ventilation control signal is transmitted to the ventilation control unit; If it is determined that no human breath remains in the indoor space, the acquired TVOC concentration is estimated to be the concentration of VOCs derived from the building materials that define the indoor space.

2. The ventilation control device according to claim 1.

3. The TVOC determination unit If the acquired TVOC concentration is equal to or greater than a predetermined regulation value, a ventilation control signal is sent to the ventilation control unit, and a display control signal is sent to the display control unit.

3. The ventilation control device according to claim 2.

4. The TVOC determination unit If there is a person in the indoor space, it is determined whether or not the TVOC concentration includes a VOC concentration based on the transition of the CO2 concentration and the transition of the TVOC concentration.

4. The ventilation control device according to claim 1, wherein the ventilation control device is a ventilation control device.

5. The TVOC determination unit If the deviation value between the CO2 concentration and the TVOC concentration is equal to or greater than a predetermined value, it is determined that the TVOC concentration includes the VOC concentration.

5. The ventilation control device according to claim 4.

6. a step in which a TVOC acquisition unit acquires a TVOC concentration from a TVOC sensor that measures a TVOC concentration in an indoor space; a CO2 acquisition unit acquiring a CO2 concentration from a CO2 sensor that measures a CO2 concentration in the indoor space; an occupancy acquisition unit acquiring occupancy information regarding the presence or absence of an occupant from an occupancy detection unit that detects the presence or absence of an occupant in the indoor space; a TVOC determination unit determining whether or not the acquired TVOC concentration includes a concentration of VOCs derived from building materials that define the indoor space, based on the TVOC concentration acquired by the TVOC acquisition unit, the CO2 concentration acquired by the CO2 acquisition unit, and the occupant information acquired by the occupant acquisition unit, and operating at least the ventilation control unit out of a ventilation control unit that controls a ventilation unit that ventilates the indoor space and a display control unit that controls a display unit that displays an alert, based on the determination result. A ventilation control method characterized by:

Images