Air conditioning system and ventilation control method

Abstract

Provided is an air conditioning system including a ventilation device. In order for ventilation to be performed for a minimum time and amount required while ensuring that the carbon dioxide concentration in a space to be ventilated does not exceed a prescribed value, the air conditioning system includes the ventilation device, and a control unit for controlling the ventilation device. The control unit acquires the carbon dioxide concentration of the space to be ventilated by the ventilation device and adjusts the ventilation amount of the ventilation device on the basis of a current value of the carbon dioxide concentration and the change of the carbon dioxide concentration over time.

Description

Air conditioning system and ventilation control method

[0001] The present disclosure relates to an air conditioning system and a ventilation control method.

[0002] There is an air conditioning system that adjusts the ventilation state of a room by controlling an air conditioner and a ventilator. For example, a technique is known in which carbon dioxide in a room is detected, and if the carbon dioxide concentration is equal to or higher than a threshold concentration, a ventilation processing mode is set that prioritizes ventilation processing, and the air conditioner 1 is stopped and the ventilator 3 is operated (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2000-088320

[0004] In an air conditioning system including a ventilation device, there is a demand for power saving by ventilating for the minimum time and amount necessary so that the carbon dioxide concentration in the space to be ventilated does not exceed a predetermined value.

[0005] However, in conventional technologies such as that shown in Patent Document 1, when the carbon dioxide concentration exceeds a threshold value, the ventilation device starts operating or the ventilation volume is increased, which has the problem of not being able to achieve sufficient power savings.

[0006] The present disclosure enables an air conditioning system including a ventilation device to perform ventilation for the minimum required time and amount within a range in which the carbon dioxide concentration in the space to be ventilated does not exceed a predetermined value.

[0007] An air conditioning system according to a first aspect of the present disclosure is an air conditioning system including a ventilation device and a control unit that controls the ventilation device, wherein the control unit acquires the carbon dioxide concentration of the space to be ventilated by the ventilation device, and adjusts the ventilation volume of the ventilation device based on the current value of the carbon dioxide concentration and the change in the carbon dioxide concentration over time.

[0008] According to the air conditioning system of the first aspect of the present disclosure, in an air conditioning system including a ventilation device, ventilation can be performed for the minimum required time and amount, so long as the carbon dioxide concentration in the space to be ventilated does not exceed a predetermined value.

[0009] In a second aspect of the present disclosure, the air conditioning system is configured to adjust the ventilation volume of the ventilator using the current value of the carbon dioxide concentration, a predetermined value that is a predetermined carbon dioxide concentration, and a time change in the carbon dioxide concentration. This allows the air conditioning system to reduce the ventilation volume while preventing the carbon dioxide concentration in the space to be ventilated from reaching a predetermined value by utilizing information on the time change in the carbon dioxide concentration.

[0010] In a third aspect of the present disclosure, in the air conditioning system according to the first aspect, the control unit adjusts the ventilation volume of the ventilator using the difference between the current carbon dioxide concentration and the predetermined carbon dioxide concentration value and the change in the carbon dioxide concentration over time. This allows the air conditioning system to reduce the ventilation volume while preventing the carbon dioxide concentration in the space to be ventilated from reaching the predetermined value by utilizing information on the difference between the current carbon dioxide concentration and the predetermined carbon dioxide concentration value.

[0011] A fourth aspect of the present disclosure is the air conditioning system according to the first aspect, wherein the control unit calculates a time required for the carbon dioxide concentration to reach a predetermined value based on the current value of the carbon dioxide concentration and a change in the carbon dioxide concentration over time, and adjusts the ventilation volume of the ventilation device based on the time required. This allows the air conditioning system to suppress the carbon dioxide concentration in the space to be ventilated from reaching the predetermined value by utilizing information on the time required for the carbon dioxide concentration to reach the predetermined value.

[0012] A fifth aspect of the present disclosure is an air conditioning system according to the first or fourth aspect, wherein the control unit increases the ventilation volume of the ventilation device by a first increase amount when the current value of the carbon dioxide concentration is smaller than a predetermined first value of the carbon dioxide concentration and the time required for the carbon dioxide concentration to reach the first predetermined value is within a first time.

[0013] In a sixth aspect of the present disclosure, in the air conditioning system according to the fifth aspect, when the arrival time is within a second time shorter than the first time, the control unit increases the ventilation volume of the ventilator by a second increase amount greater than the first increase amount. This allows the air conditioning system to suppress the ventilation volume while preventing the carbon dioxide concentration from exceeding a first predetermined value even when the carbon dioxide concentration is increasing rapidly.

[0014] In a seventh aspect of the present disclosure, in the air conditioning system according to the first or fourth aspect, when the current value of the carbon dioxide concentration is greater than a predetermined second value of the carbon dioxide concentration and the time until the carbon dioxide concentration reaches the second predetermined value is within a third time, the control unit reduces the sensor value of the ventilation device by a first reduction amount. This enables the air conditioning system to suppress the ventilation volume when the carbon dioxide concentration is decreasing rapidly.

[0015] An eighth aspect of the present disclosure is the air conditioning system described in the seventh aspect, wherein, when the arrival time is within a fourth time that is shorter than the third time, the control unit reduces the ventilation volume of the ventilation device by a second reduction amount that is greater than the first reduction amount, or stops operation of the ventilation device.

[0016] A ninth aspect of the present disclosure is an air conditioning system according to any one of the first to eighth aspects, wherein the control unit stops operation of the ventilation device when the current value of the carbon dioxide concentration is equal to or lower than a predetermined threshold value of the carbon dioxide concentration.

[0017] A tenth aspect of the present disclosure is an air conditioning system according to any one of the first to ninth aspects, wherein the air conditioning system includes a plurality of ventilation devices, and the control unit adjusts the ventilation volume of the plurality of ventilation devices based on the current value of the carbon dioxide concentration and the change in the carbon dioxide concentration over time.

[0018] An eleventh aspect of the present disclosure is an air conditioning system described in any of the first to tenth aspects, wherein the control unit determines the ventilation volume at a time interval longer than the time interval for measuring the carbon dioxide concentration.

[0019] In a twelfth aspect of the present disclosure, there is provided the air conditioning system according to any one of the first to eleventh aspects, wherein the control unit smoothes the acquired carbon dioxide concentration to calculate a change in the carbon dioxide concentration over time, thereby reducing the adverse effects of fluctuations in the carbon dioxide concentration data.

[0020] A thirteenth aspect of the present disclosure is an air conditioning system described in any of the first to twelfth aspects, wherein the air conditioning system includes the ventilation device and a communication device capable of communicating with the ventilation device, and the communication device has the control unit.

[0021] A ventilation control method according to a fourteenth aspect of the present disclosure is an air conditioning system including a ventilation device and a control unit that controls the ventilation device, wherein the control unit acquires the carbon dioxide concentration of a space to be ventilated by the ventilation device, and adjusts the ventilation volume of the ventilation device based on the current value of the carbon dioxide concentration and the change in the carbon dioxide concentration over time.

[0022] A program according to a fifteenth aspect of the present disclosure is provided in an air conditioning system including a ventilation device and a control unit that controls the ventilation device, and causes the control unit to acquire the carbon dioxide concentration of a space that is to be ventilated by the ventilation device, and adjust the ventilation volume of the ventilation device based on the current value of the carbon dioxide concentration and the change in the carbon dioxide concentration over time.

[0023] FIG. 1 is a diagram (1) showing an example of the configuration of an air conditioning system according to the present embodiment. FIG. 2 is a diagram for explaining an overview of processing according to the present embodiment. FIG. 3 is a diagram for explaining an example of the configuration of an air conditioning system according to the present embodiment. FIG. 4 is a diagram for explaining an example of the hardware configuration of a computer according to the present embodiment. FIG. 5 is a flowchart showing an example of ventilation volume adjustment processing according to the present embodiment. FIG. 1 is a diagram for explaining a ventilation volume determination processing according to Example 1. FIG. 2 is a diagram for explaining a ventilation volume determination processing according to Example 1. FIG. 3 is a diagram for explaining a ventilation volume determination processing according to Example 1. FIG. 1 is a diagram for explaining a ventilation volume determination processing according to Example 2. FIG. 2 is a diagram for explaining a ventilation volume determination processing according to Example 2. FIG. 3 is a diagram for explaining a ventilation volume determination processing according to Example 2. FIG. 1 is a diagram for explaining a ventilation volume determination processing according to Example 3. FIG. 2 is a diagram for explaining a ventilation volume determination processing according to Example 3. FIG. 3 is a diagram for explaining a ventilation volume determination processing according to Example 3. FIG. 4 is a diagram for explaining a ventilation volume determination processing according to Example 3. FIG. 5 is a flowchart (1) showing an example of ventilation volume adjustment processing according to Example 4. Fig. 10 is a diagram for explaining the ventilation volume adjustment process according to Example 4. Fig. 11 is a flowchart (2) showing an example of the ventilation volume adjustment process according to Example 4. Fig. 12 is a diagram for explaining the effect of the air conditioning system according to the present embodiment.

[0024] Hereinafter, an embodiment of the present disclosure (the present embodiment) will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0025] <Configuration of Air Conditioning System> Fig. 1 is a diagram (1) showing an example configuration of an air conditioning system according to this embodiment. In the example of Fig. 1, the air conditioning system 1 includes a communication device 10, ventilation devices 11a, 11b, ..., a CO2 sensor 12, and a management server 100 capable of communicating with the communication device 10 via a communication network N. The air conditioning system 1 may also include air conditioners 13a, 13b, ..., and an administrator terminal 20. In the following description, the term "ventilation device 11" will be used to refer to any ventilation device among the ventilation devices 11a, 11b, .... The term "air conditioner 13" will be used to refer to any air conditioner among the air conditioners 13a, 13b, ....

[0026] The ventilation device 11 is a ventilation device that targets ventilation of the target area 2. The number of ventilation devices 11 shown in FIG. 1 is an example, and the number of ventilation devices 11 may be one or more. The target area 2 is an example of a space that is targeted for ventilation by the ventilation device 11.

[0027] The CO2 sensor 12 is a sensor that measures the carbon dioxide concentration (hereinafter referred to as CO2 concentration) in the target area 2. The CO2 sensor 12 may be provided in the target area 2, or may be provided in a space through which air drawn in from the target area 2 passes. The CO2 sensor 12 may also be provided in the ventilation device 11 or the air conditioner 13.

[0028] The air conditioner 13 is an air conditioning device that conditions the target area 2. Note that the number of air conditioners 13 shown in Fig. 1 is an example, and the number of air conditioners 13 may be one or more. In this embodiment, the air conditioner 13 is optional and not essential.

[0029] The communication device 10 is an information processing device having a computer configuration, and is communicatively connected to, for example, the ventilation device 11, the CO2 sensor 12, and the air conditioner 13. The communication device 10 can also communicate with the management server 100 or the administrator terminal 20 via a communication network N, such as the Internet or a local area network (LAN). The communication device 10 acquires, for example, measurement data of the CO2 concentration in the target area 2 measured by the CO2 sensor 12, operation data of the ventilation device 11, and operation data of the air conditioner, and transmits the data to the management server 100. The communication device 10 also transfers control data addressed to the ventilation device 11 and control data addressed to the air conditioner 13, received from the management server 100, to the ventilation device 11 and the air conditioner 13.

[0030] The management server 100 is an information processing device having a computer configuration or a system including multiple computers. In the example of Fig. 1, the management server 100 includes a communication unit 101, a control unit 102, a storage unit 110, etc.

[0031] The communication unit 101 connects the management server 100 to the communication network N and executes communication processing for communicating with the communication device 10, the administrator terminal 20, and the like.

[0032] The control unit 102 is a processor such as a CPU (Central Processing Unit) included in the management server 100. The control unit 102 acquires the CO2 concentration in the target area 2 by executing a program stored in a storage medium such as the storage unit 110, and executes a ventilation volume adjustment process to adjust the ventilation volume of the ventilation device 11 based on the current value of the CO2 concentration and the change in the CO2 concentration over time.

[0033] The storage unit 110 is realized by a storage device or the like included in the management server 100, and stores various data, information, programs, and the like, including, for example, CO2 concentration data (CO2 concentration data 111) acquired by the control unit 102, and various setting information 112. Note that the storage unit 110 may be realized by another server that can communicate with the management server 100 via the communication network N, cloud storage, or the like.

[0034] The administrator terminal 20 is an information processing device such as a PC, tablet terminal, or smartphone that is used by an administrator 21 or the like who manages the air conditioning system 1. The administrator 21 can, for example, use the administrator terminal 20 to log in to the management server 100 and set or change the setting information 112. Note that in this embodiment, the administrator terminal 20 is optional and not essential.

[0035] <Processing Overview> Fig. 2 is a diagram for explaining the processing overview according to this embodiment. This diagram shows an example of the change over time in the CO2 concentration 201 in the target area 2, with the horizontal axis representing time and the vertical axis on the left representing the CO2 concentration [ppm]. This diagram also shows the change over time in the CO2 concentration 201 in the target area 2, with the horizontal axis representing time and the vertical axis on the right representing the ventilation volume [m ３ / h] shows an example of control of the ventilation volume 205 of the ventilation device 11 by the control unit 102.

[0036] CO2 concentration (carbon dioxide concentration) is 1 m ３ The CO2 concentration in the outside air is about 400 ppm, and the standard for the carbon dioxide concentration indoors is, for example, 1000 ppm or less.

[0037] When the ventilation device 11 is stopped, the CO2 concentration in the target area 2 increases due to people's breathing, for example, as shown in the time period t0 to t1 in Figure 2. Furthermore, the change in the CO2 concentration 201 over time differs depending on the number of people in the target area 2.

[0038] Therefore, the control unit 102 adjusts the ventilation volume of the ventilation device 11 based on, for example, the current value 202 of the CO2 concentration 201 in the target area 2 and the slope (change over time) 203 of the CO2 concentration 201 so that the CO2 concentration 201 falls within a range 206 from a first predetermined value (e.g., 1000 ppm) to a second predetermined value (e.g., 800 ppm).

[0039] For example, at time t1 in Figure 2, the control unit 102 starts operating the ventilation device 11 when it determines that the CO2 concentration 201 is likely to exceed a first predetermined value based on the current value 202 of the CO2 concentration 201 and the slope 203 of the CO2 concentration 201.

[0040] Preferably, the control unit 102 controls the ventilation volume of the ventilation device 11 in a stepwise manner based on the current value 202 of the CO2 concentration 201 and the slope 203 of the CO2 concentration 201. For example, the control unit 102 sets the ventilation volume of the ventilation device 11 to a larger value when the CO2 concentration 201 reaches the first predetermined value in a shorter time.

[0041] Note that the CO2 concentration 201 in the target area 2 changes depending on the number of people in the target area 2, even if the ventilation rate is the same. For example, assume that the number of people in the target area 2 decreases around time t2 in FIG. 2 , causing the CO2 concentration 201 in the target area 2 to decrease. In this case, for example, at time t2 in FIG. 2 , the control unit 102 reduces the ventilation rate of the ventilation device 11 when the CO2 concentration 201 is likely to fall below a second predetermined value based on the current value of the CO2 concentration 201 and the slope of the CO2 concentration 201. In the example of FIG. 2 , the control unit 102 reduces the ventilation rate of the ventilation device 11 by one level at time t2.

[0042] Similarly, for example, at time t3 in Fig. 2, when the current value of CO2 concentration 201 and the slope of CO2 concentration 201 indicate that CO2 concentration 201 is unlikely to exceed the first predetermined value, the control unit 102 again increases the ventilation rate of the ventilation device 11. In the example of Fig. 2, the control unit 102 increases the ventilation rate of the ventilation device 11 by one step at time t3.

[0043] Similarly, for example, at time t4 in Fig. 2, when the current value of CO2 concentration 201 and the slope of CO2 concentration 201 indicate that CO2 concentration 201 is likely to fall below the second predetermined value, the control unit 102 again reduces the ventilation rate of the ventilation device 11. In the example of Fig. 2, the control unit 102 reduces the ventilation rate of the ventilation device 11 by one step at time t4.

[0044] Furthermore, the control unit 102 stops the operation of the ventilation device 11, for example, at time t5 in Figure 2, when the current value of the CO2 concentration 201 and the slope of the CO2 concentration 201 indicate that the CO2 concentration 201 has fallen below a second predetermined value and is continuing to decrease.

[0045] For example, in the conventional technology disclosed in Patent Document 1, the operation of the ventilation device is started when the CO2 concentration exceeds a threshold value. However, in this method, when the CO2 concentration exceeds the threshold value, the operation of the ventilation device is started even if the increase in the CO2 concentration is gradual and does not reach 1000 ppm.

[0046] On the other hand, in this embodiment, the ventilation device 11 starts operating when the CO2 concentration 201 is likely to exceed 1000 ppm (an example of a first predetermined value) based on the current value 202 of the CO2 concentration 201 and the slope 203 of the CO2 concentration 201. Therefore, the air conditioning system 1 according to this embodiment can suppress unnecessary operation of the ventilation device 11. For example, the air conditioning system 1 can delay the start of operation of the ventilation device 11 until the last possible moment.

[0047] Furthermore, the air conditioning system 1 can suppress the ventilation rate while preventing the CO2 concentration from reaching the predetermined concentration by using any of information on the change in CO2 concentration over time, the difference between a predetermined value and the CO2 concentration, or the time it takes for the CO2 concentration to reach the predetermined value. Furthermore, the air conditioning system 1 can reduce the ventilation rate while preventing the CO2 concentration from reaching the predetermined concentration by changing the amount by which the ventilation rate is increased depending on the time it takes for the CO2 concentration to reach the predetermined concentration.

[0048] Furthermore, in conventional technology, if the CO2 concentration exceeds a threshold, the operation of the ventilation device 11 continues even if the CO2 concentration is on a decreasing trend. On the other hand, in this embodiment, even if the CO2 concentration exceeds 800 ppm (an example of a second predetermined value), if the CO2 concentration is on a decreasing trend, the ventilation rate of the ventilation device 11 is reduced or the operation of the ventilation device 11 is stopped. Therefore, with the air conditioning system 1 according to this embodiment, unnecessary operation of the ventilation device 11 can be further suppressed.

[0049] As described above, the air conditioning system 1 according to this embodiment can perform ventilation for the minimum required time and amount within a range in which the carbon dioxide concentration in the space to be ventilated (target area 2) does not exceed a predetermined value.

[0050] The configuration of the air conditioning system 1 shown in Fig. 1 is an example. For example, the communication unit 101, the control unit 102, the storage unit 110, and the like that are included in the management server 100 in Fig. 1 may be included in the communication device 10 as shown in Fig. 3. This allows the air conditioning system 1 to adjust the ventilation volume of the ventilator 11 based on the current value of the CO2 concentration 201 in the target area 2 and the change in the CO2 concentration 201 over time, without relying on the management server 100, so that the CO2 concentration 201 falls within a predetermined value range 206.

[0051] 4, the communication unit 101, the control unit 102, the storage unit 110, etc. may be included in the ventilation device 11. This allows the air conditioning system 1 to adjust the ventilation volume of the ventilation device 11 based on the current value of the CO2 concentration 201 in the target area 2 and the change in the CO2 concentration 201 over time, without relying on the communication device 10, so that the CO2 concentration 201 falls within a predetermined value range 206.

[0052] Furthermore, the communication unit 101, the control unit 102, the storage unit 110, etc. may be provided in a distributed manner in the management server 100, the communication device 10, the ventilation device 11, etc. In short, the communication unit 101, the control unit 102, the storage unit 110, etc. may be provided in any device within the air conditioning system 1 as long as they are included in the air conditioning system 1.

[0053] <Hardware Configuration> The management server 100, the communication device 10, the administrator terminal 20, etc. have the hardware configuration of a computer 500 as shown in Fig. 5. The management server 100 may be configured by a plurality of computers 500. The ventilation device 11 may also have the hardware configuration of a computer 500.

[0054] 5 is a diagram showing an example of the hardware configuration of a computer according to this embodiment. The computer 500 includes, for example, a control unit 102, a memory 501, a storage device 502, a communication I / F (Interface) 503, an output device 504, an input device 505, a drive device 506, and the like.

[0055] The control unit 102 is a processor such as a CPU that realizes various functions by executing predetermined programs stored in a storage medium such as the storage device 502 or the memory 501. Note that the control unit 102 may include a processor other than the CPU, such as a GPU (Graphics Processing Unit) or a DSP (Digital Signal Processor).

[0056] The memory 501 includes, for example, a RAM (Random Access Memory), which is a volatile memory used as a work area for the control unit 102, and a ROM (Read Only Memory), which is a nonvolatile memory that stores programs for starting the control unit 102. The storage device 502 is a nonvolatile, large-capacity storage device that stores an OS (Operating System), programs such as applications, and various data.

[0057] The communication I / F 503 includes various communication interfaces for communicating with other devices, such as a network interface card (NIC) that connects the computer 500 to a communication network N, or a wireless communication interface that performs wireless wide area network (WAN) communication or wireless LAN communication.

[0058] The output device 504 is an output device that outputs to the outside, such as a display, a speaker, or an LED (Light Emitting Diode). The input device 505 is an input device that accepts input from the outside, such as a touch panel, a keyboard, or a pointing device. Note that the output device 504 and the input device 505 may be display input devices such as a touch panel display.

[0059] The drive device 506 is a device for connecting a storage medium (recording medium) 507 to the computer 500. The storage medium 507 here includes, for example, a medium that records information optically, electrically, or magnetically, such as a CD-ROM, a flexible disk, or a magneto-optical disk. The storage medium 507 may also include, for example, a semiconductor memory that records information electrically, such as a ROM or a flash memory. The bus 508 is commonly connected to the above components and transmits, for example, address signals, data signals, and various control signals.

[0060] <Processing Flow> Next, the processing flow of the ventilation control method according to this embodiment will be described.

[0061] 6 is a flowchart showing an example of ventilation volume adjustment processing according to this embodiment. This processing shows an example of ventilation volume adjustment processing executed by the air conditioning system 1.

[0062] In step S601, the control unit 102 acquires the CO2 concentration (carbon dioxide concentration) in the target area 2. The target area 2 is an example of a space to be ventilated by the ventilation device 11.

[0063] Preferably, the control unit 102 acquires the CO2 concentration data 111 for the target area 2 measured by the CO2 sensor 12 at a first time interval (e.g., one-minute intervals), and sets the moving average of the CO2 concentration for a predetermined period (e.g., from the current time to 10 minutes ago) as the CO2 concentration for the target area 2. This makes it possible to reduce, for example, adverse effects due to fluctuations in the CO2 concentration data 111 for the target area 2.

[0064] The moving average is an example of a process for smoothing the CO2 concentration data 111. The control unit 102 may use a method other than the moving average to smooth the CO2 concentration data 111. The above-mentioned predetermined time interval (1 minute) and predetermined period (10 minutes) are merely examples, and other values ​​may be used.

[0065] The control unit 102 may acquire the CO2 concentration data 111 of the target area 2 measured at predetermined time intervals from the storage unit 110 or from the communication device 10. The control unit 102 may also acquire the CO2 concentration data 111 of the target area 2 from a cloud service that acquires and manages measurement results from the CO2 sensor 12, or may acquire the data from the CO2 sensor 12. The control unit 102 sets the CO2 concentration data 111 of the target area 2 before performing the processing of step S602, or a value obtained by smoothing the CO2 concentration data 111 of the target area 2 measured at predetermined time intervals using a method such as a moving average, as the current value of the CO2 concentration of the target area 2.

[0066] In step S602, the control unit 102 determines the ventilation volume of the ventilation device 11 based on the current value of the CO 2 concentration in the target area 2 and the change in the CO 2 concentration in the target area 2 over time.

[0067] Preferably, the control unit 102 executes a ventilation amount determination process to determine the ventilation amount of the ventilation device 11 at a second time interval (e.g., 5-minute interval) longer than the first time interval, based on the CO2 concentration in the target area 2 acquired at a first time interval (e.g., 1-minute interval). The ventilation amount determination process will be described later with reference to several examples.

[0068] In step S603, the control unit 102 determines whether the newly determined ventilation volume has been changed from the previous ventilation volume determined in step S602. If the ventilation volume has been changed, the control unit 102 proceeds to step S604. On the other hand, if the ventilation volume has not been changed, the control unit 102 ends the process of FIG. 6.

[0069] When the process proceeds to step S604, the control unit 102 instructs the ventilation device 11 to change the ventilation volume. In the example of Fig. 1 , the control unit 102 transmits control data to the communication device 10, instructing the ventilation device 11, whose ventilation volume has been changed, to change the ventilation volume. In response to this, the communication device 10 transfers the control data received from the management server 100 to the ventilation device 11, and the ventilation device 11 changes the ventilation volume in accordance with the transferred control data. Note that changing the ventilation volume includes starting or stopping the operation of the ventilation device 11.

[0070] (Ventilation Volume Determination Process) Next, the ventilation volume determination process executed by the control unit 102 in step S602 of FIG. 6 will be described.

[0071] 7A to 7C are diagrams for explaining a process for determining a ventilation volume according to Example 1. For example, as shown in Fig. 7A, the control unit 102 may determine the ventilation volume of the ventilation device 11 using correspondence information 710 that pre-stores a current value 711 of the CO2 concentration and a ventilation volume 713 of the ventilation device 11 that corresponds to a slope 712 of the CO2 concentration.

[0072] In the example of the correspondence information 710, the ventilation volume 713 of the ventilation device 11 is represented by three levels: "0 (stop)," "L," and "H." Here, "0 (stop)" indicates that the operation of the ventilation device 11 is stopped. Furthermore, "L" indicates that the ventilation device 11 is operated at low power, and "H" indicates that the ventilation device 11 is operated at high power. Furthermore, in the correspondence information 710, "-Y" represents a negative slope threshold (e.g., "-2"), and "Z" represents a positive slope threshold (e.g., "8"). For example, if the current value x of the CO2 concentration in the target area 2 is 850 ppm and the slope a of the CO2 concentration in the target area 2 is a value between -Y and Z (e.g., "1"), the control unit 102 can determine the ventilation volume of the ventilation device 11 to be "L" based on the correspondence information 710.

[0073] Here, the slope a is found by calculating the difference between the "current CO2 concentration value at the current time" and the "current CO2 concentration value one minute prior to the current time." For example, the control unit 102 calculates the slope a using the following formula (1): Slope a = (moving average CO2 concentration at the current time) - (moving average CO2 concentration one minute prior to the current time) (Formula 1). The moving average CO2 concentration at the current time is calculated, for example, by averaging the CO2 concentration over the 10 minutes from the current time to 10 minutes prior. Similarly, the moving average CO2 concentration one minute prior to the current time is calculated by averaging the CO2 concentration over the 10 minutes from 1 minute prior to the current time to 11 minutes prior. The "current value" may be a moving average as in Formula 1, or may be smoothed by some other method, or the CO2 concentration data 111 measured by the CO2 sensor 12 may be used. Furthermore, when calculating the slope a, the "current value of the CO2 concentration one minute before the current time" is just one example, and the difference from the current value of the CO2 concentration a predetermined time ago (e.g., 30 seconds, 1 minute, 5 minutes, etc.) can be used.

[0074] As another example, in the correspondence information 720 shown in FIG. 7B , the ventilation volume 721 of the ventilation device 11 is indicated by five levels: "-2," "-1," "0," "+1," and "+2." Here, "-2" indicates that the ventilation volume level of the ventilation device 11 is to be lowered by two levels, and "-1" indicates that the ventilation volume level of the ventilation device 11 is to be lowered by one level. "0" indicates that the ventilation volume level of the ventilation device 11 is not changed. Furthermore, "+1" indicates that the ventilation volume level of the ventilation device 11 is to be increased by one level, and "+2" indicates that the ventilation volume level of the ventilation device 11 is to be increased by two levels. Note that if the ventilation volume level after the change exceeds the maximum value, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the maximum value. Similarly, if the ventilation volume level after the change is below the minimum value, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the minimum value.

[0075] As another example, the correspondence information 730 shown in FIG. 7C indicates the ventilation volume 731 of the ventilation device 11 in five levels: "-40%, "-20%, "0", "+20%,," and "+40%." Here, "-40%" indicates that the ventilation volume of the ventilation device 11 is reduced by 40%, and "-20%" indicates that the ventilation volume of the ventilation device 11 is reduced by 20%. "0" indicates that the ventilation volume of the ventilation device 11 is not changed. Furthermore, "+20%" indicates that the ventilation volume of the ventilation device 11 is increased by 20%, and "+40%" indicates that the ventilation volume of the ventilation device 11 is increased by 40%. Note that if the ventilation volume after the change exceeds the maximum value, the control unit 102 sets the ventilation volume of the ventilation device 11 to the maximum value. Similarly, if the ventilation volume after the change is below the minimum value, the control unit 102 sets the ventilation volume of the ventilation device 11 to the minimum value.

[0076] Such correspondence information 710, 720, and 730 is included in, for example, the setting information 112 stored in advance in the air conditioning system 1. Furthermore, the setting values ​​of the correspondence information 710, 720, and 730 may be changeable by the administrator 21 or the like using the administrator terminal 20.

[0077] 8A, 8B, and 9 are diagrams for explaining a process for determining a ventilation volume according to Example 2. For example, as shown in Fig. 8A, when the slope a of the CO2 concentration is "a>0", the control unit 102 may determine the ventilation volume of the ventilation device 11 based on the time b required for the CO2 concentration in the target area 2 to reach a first predetermined value (e.g., 1000 ppm).

[0078] The slope a of the CO2 concentration can be calculated, for example, by subtracting the moving average of the CO2 concentration one minute before the current time from the moving average of the CO2 concentration at the current time. The arrival time b required for the CO2 concentration in the target area 2 to reach the first predetermined value can be calculated, for example, from the current CO2 concentration x and the slope a of the CO2 concentration using the following formula (2): Arrival time b = 1 / a × (1000 - x) ... (Formula 2)

[0079] For example, when the gradient a of the CO2 concentration is "a>0", the control unit 102 controls the ventilation volume of the ventilation device 11 based on the arrival time b as follows.

[0080] If the arrival time b is less than a predetermined first time T1 (e.g., 20 minutes) and greater than or equal to a predetermined second time T2 (e.g., 10 minutes), the control unit 102 increases the ventilation volume level of the ventilation device 11 by one level.

[0081] If the arrival time b is less than the second time T2 and is equal to or greater than a predetermined third time T3 (for example, 5 minutes), the control unit 102 increases the ventilation volume level of the ventilation device 11 by two steps.

[0082] If the arrival time is less than the third time T3, the control unit 102 increases the ventilation volume level of the ventilation device 11 by three levels. Note that if the ventilation volume level of the ventilation device 11 exceeds the maximum level as a result of the above control, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the maximum level.

[0083] Here, as an example, the control unit 102 controls the ventilation volume of the ventilation device 11 every five minutes, and the first time T1 is set to 20 minutes, which is four times five minutes. The second time T2 is set to 10 minutes, which is two times five minutes, and the third time T3 is set to five minutes. However, the above first time T1, second time T2, and third time T3 are merely examples, and other values ​​may be used.

[0084] In this way, it is desirable for the control unit 102 to set the ventilation volume of the ventilation device 11 to be larger if the CO2 concentration in the target area 2 reaches the first predetermined value in a shorter time.

[0085] Preferably, when the CO2 concentration in the target area 2 exceeds a predetermined threshold (e.g., 700 ppm), the control unit 102 executes the process of increasing the ventilation volume of the ventilation device 11. Alternatively, when the CO2 concentration in the target area is equal to or lower than the predetermined threshold, the control unit 102 stops the operation of the ventilation device 11.

[0086] Furthermore, for example, when the slope a of the CO2 concentration is "a≦0" as shown in FIG. 8B, the control unit 102 may determine the ventilation volume of the ventilation device 11 based on the time b required for the CO2 concentration in the target area 2 to reach a second predetermined value (e.g., 800 ppm).

[0087] For example, when the gradient a of the CO2 concentration is "a≦0", the control unit 102 controls the ventilation volume of the ventilation device 11 based on the arrival time b as follows.

[0088] If the arrival time b is less than a predetermined fourth time T4 (e.g., 20 minutes) and greater than or equal to a predetermined fifth time T5 (e.g., 10 minutes), the control unit 102 reduces the ventilation volume level of the ventilation device 11 by one level.

[0089] If the arrival time b is less than the fifth time T5 and is equal to or greater than a predetermined sixth time T6 (for example, 5 minutes), the control unit 102 reduces the ventilation volume level of the ventilation device 11 by two stages.

[0090] If the arrival time is less than the sixth time T6, the control unit 102 lowers by three levels the ventilation volume level of the ventilation device 11. Note that if the ventilation volume level of the ventilation device 11 falls below the minimum level as a result of the above control, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the minimum level or stops the operation of the ventilation device 11.

[0091] Here, as an example, the fourth time T4 is 20 minutes, the fifth time T5 is 10 minutes, and the sixth time T6 is 5 minutes. However, the fourth time T4, the fifth time T5, and the sixth time T6 are merely examples, and other values ​​may be used.

[0092] In this way, it is desirable for the control unit 102 to set the ventilation volume of the ventilation device 11 to a smaller value if the CO2 concentration in the target area 2 reaches the second predetermined value in a shorter time.

[0093] As another example, the control unit 102 may determine the ventilation volume of the ventilation device 11 based on the gradient a of the CO2 concentration in the target area 2 when the gradient a of the CO2 concentration is "a≦0", for example, as shown in Figure 9.

[0094] For example, when the gradient a of the CO2 concentration is "a≦0", the control unit 102 controls the ventilation volume of the ventilation device 11 based on the gradient a as follows.

[0095] If the slope b is less than a predetermined first slope Y1 (e.g., -2 = -20 ppm / 10 minutes) and greater than or equal to a predetermined second slope Y2 (e.g., -5 = -50 ppm / 10 minutes), the control unit 102 lowers the ventilation volume level of the ventilation device 11 by one level.

[0096] If the slope b is less than the second slope Y2, or if the CO2 concentration in the target area 2 is below a predetermined threshold (e.g., 700 ppm), the control unit 102 reduces the ventilation volume level of the ventilation device 11 by two levels.

[0097] If the ventilation volume level of the ventilation device 11 falls below the minimum level due to the above control, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the minimum level or stops the operation of the ventilation device 11.

[0098] Preferably, the control unit 102 executes the process of reducing the ventilation volume of the ventilation device 11 described above when the CO2 concentration in the target area 2 is equal to or lower than a first predetermined value (for example, 1000 ppm).

[0099] 10 is a diagram (1) for explaining a process for determining a ventilation volume according to Example 3. The control unit 102 may adjust the ventilation volume of the ventilation device 11 using, for example, a difference c between the current CO2 concentration value in the target area 2 and a predetermined CO2 concentration value (e.g., 1000 ppm) and a slope (change over time) a of the CO2 concentration.

[0100] 11A to 11C are diagrams (2) to (4) for explaining the process of determining the ventilation volume according to Example 3. For example, as shown in Fig. 11A, the control unit 102 may determine the ventilation volume of the ventilation device 11 using correspondence information 1110 that pre-stores a difference 1111 between a predetermined value of the CO2 concentration and the current value of the CO2 concentration, a gradient 1112 of the CO2 concentration, and a ventilation volume 1113 of the ventilation device 11 that corresponds to the difference 1111.

[0101] In the example of the correspondence information 1110, the ventilation volume 1113 of the ventilation device 11 is represented by three levels: "0 (stop)," "L," and "H." Here, "0 (stop)" indicates that the operation of the ventilation device 11 is stopped. Furthermore, "L" indicates that the ventilation device 11 is operated at low power, and "H" indicates that the ventilation device 11 is operated at high power. Furthermore, in the correspondence information 1110, "-Y" is a negative slope threshold (e.g., "-2"), and "Z" is a positive slope threshold (e.g., "8"). For example, if the difference c between the predetermined CO2 concentration value and the current CO2 concentration value is 100, and the slope a of the CO2 concentration is a value between Y and Z (e.g., "5"), the control unit 102 can determine the ventilation volume of the ventilation device 11 to be "L" based on the correspondence information 1110.

[0102] As another example, in the correspondence information 1120 shown in FIG. 11B , the ventilation volume 1121 of the ventilation device 11 is indicated by five levels: “−2,” “−1,” “0,” “+1,” and “+2.” Here, “−2” indicates that the ventilation volume level of the ventilation device 11 is to be lowered by two levels, and “−1” indicates that the ventilation volume level of the ventilation device 11 is to be lowered by one level. “0” indicates that the ventilation volume level of the ventilation device 11 is not changed. Furthermore, “+1” indicates that the ventilation volume level of the ventilation device 11 is to be increased by one level, and “+2” indicates that the ventilation volume level of the ventilation device 11 is to be increased by two levels. Note that if the ventilation volume level after the change exceeds the maximum value, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the maximum value. Similarly, if the ventilation volume level after the change is below the minimum value, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the minimum value or stops operation of the ventilation device 11.

[0103] As another example, the correspondence information 1130 shown in FIG. 11C indicates the ventilation volume 1131 of the ventilation device 11 in five levels: "-40%, "-20%, "0", "+20%,," and "+40%." Here, "-40%" indicates that the ventilation volume of the ventilation device 11 is reduced by 40%, and "-20%" indicates that the ventilation volume of the ventilation device 11 is reduced by 20%. "0" indicates that the ventilation volume of the ventilation device 11 is not changed. Furthermore, "+20%" indicates that the ventilation volume of the ventilation device 11 is increased by 20%, and "+40%" indicates that the ventilation volume of the ventilation device 11 is increased by 40%. Note that if the ventilation volume after the change exceeds the maximum value, the control unit 102 sets the ventilation volume of the ventilation device 11 to the maximum value. Similarly, if the ventilation volume after the change falls below the minimum value, the control unit 102 sets the ventilation volume of the ventilation device 11 to the minimum value or stops operation of the ventilation device 11.

[0104] Such correspondence information 1110, 1120, and 1130 is included in, for example, setting information 112 stored in advance in the air conditioning system 1. Furthermore, the setting values ​​of the correspondence information 1110, 1120, and 1130 may be changeable by the administrator 21 or the like using the administrator terminal 20.

[0105] Furthermore, the control unit 102 may determine the ventilation volume of the ventilation device 11 without relying on the correspondence information 1110 , 1120 , and 1130 .

[0106] For example, when the slope a of the CO2 concentration is "a>0", the control unit 102 may control the ventilation volume of the ventilation device 11 based on the difference c between a predetermined value of the CO2 concentration and the current value of the CO2 concentration as follows.

[0107] When the difference c between the predetermined CO2 concentration value and the current CO2 concentration value satisfies c<T7×a, the control unit 102 increases the ventilation volume level of the ventilator 11 by one level, where T7 is a preset seventh time T7 (e.g., 20 minutes), and a is the slope a of the CO2 concentration.

[0108] When the difference c between the predetermined CO2 concentration value and the current CO2 concentration value satisfies c<T8×a, the control unit 102 increases the ventilation volume level of the ventilation device 11 by two levels. Here, T8 is a preset eighth time T8 (e.g., 10 minutes). Note that if the ventilation volume level of the ventilation device 11 exceeds the maximum level as a result of the above control, the control unit 102 sets the ventilation volume level of the ventilation device 11 to the maximum level.

[0109] Furthermore, when the gradient a of the CO2 concentration is "a≦0", the control unit 102 may control the ventilation volume of the ventilation device 11 based on the gradient a of the CO2 concentration as follows.

[0110] When the gradient a of the CO2 concentration satisfies a<A1, the control unit 102 decreases the ventilation volume of the ventilation device 11 by one step, where A1 is a predetermined first gradient (for example, −5).

[0111] When the gradient a of the CO2 concentration satisfies a<A2, the control unit 102 reduces the ventilation rate of the ventilation device 11 by two stages. Here, A2 is a predetermined second gradient (e.g., −10). If the ventilation rate level of the ventilation device 11 falls below the minimum level as a result of the above control, the control unit 102 sets the ventilation rate level of the ventilation device 11 to the minimum level or stops the operation of the ventilation device 11.

[0112] For example, according to the first to third embodiments described above, the control unit 102 can determine the ventilation volume of the ventilation device 11 based on the current value of the CO2 concentration in the target area 2 and the change in the CO2 concentration over time.

[0113] [Example 4] In Example 4, an example of processing will be described in which the air conditioning system 1 includes multiple ventilation devices 11, and the control unit 102 adjusts the ventilation volume of the multiple ventilation devices 11 based on the current value of the CO2 concentration in the target area 2 and the change in the CO2 concentration in the target area 2 over time.

[0114] (Ventilation Volume Adjustment Process 1) Fig. 12 is a flowchart (1) illustrating an example of ventilation volume adjustment process according to Example 4. Note that detailed description of processes similar to the ventilation volume adjustment process described in Fig. 6 will be omitted here.

[0115] In step S1201, the control unit 102 acquires the CO2 concentration (carbon dioxide concentration) in the target area 2. Here, for example, as shown in Fig. 13, it is assumed that one CO2 sensor 12 is installed in the target area 2. Furthermore, it is assumed that the CO2 sensor 12 is installed, for example, in a location in the target area 2 where there are many people, and the control unit 102 adjusts the ventilation volume of the ventilation device 11b that is closest to the CO2 sensor.

[0116] Preferably, the control unit 102 acquires CO2 concentration data 111 for the target area 2 measured by the CO2 sensor 12 at a first time interval (e.g., one-minute intervals), and sets a moving average of the CO2 concentration for a predetermined period (e.g., from the current time to 10 minutes ago) as the CO2 concentration for the target area 2. Note that the moving average is an example of smoothing the CO2 concentration data 111. The control unit 102 may smooth the concentration data 111 using a method other than the moving average.

[0117] In step S1202, the control unit 102 determines the ventilation volume of the ventilation device 11b based on the current value of the CO 2 concentration in the target area 2 and the change in the CO 2 concentration in the target area 2 over time.

[0118] Preferably, the control unit 102 executes a ventilation amount determination process to determine the ventilation amount of the ventilation device 11 at a second time interval (e.g., 5-minute interval) longer than the first time interval based on the CO2 concentration in the target area 2 acquired at a first time interval (e.g., 1-minute interval). Note that the ventilation amount determination process can be, for example, the process described in Examples 1 to 3.

[0119] In step S1203, the control unit 102 determines whether the ventilation volume of the ventilation device 11b has been changed. If the ventilation volume has been changed, the control unit 102 proceeds to step S1204. On the other hand, if the ventilation volume has not been changed, the control unit 102 ends the process of FIG. 12.

[0120] 1, the control unit 102 transmits control data to the communication device 10 instructing the ventilator 11b, whose ventilation rate has been changed, to change the ventilation rate. In response, the communication device 10 transfers the control data received from the management server 100 to the ventilator 11b, and the ventilator 11b changes the ventilation rate in accordance with the transferred control data.

[0121] If two or more CO2 sensors 12 are installed in the target area 2, the control unit 102 may execute the same process for each of the ventilation devices 11 that are close to each CO2 sensor 12.

[0122] The process shown in Fig. 12 is an example. Instead of the process shown in Fig. 12, the control unit 102 may execute, for example, a ventilation volume adjustment process as shown in Fig. 14.

[0123] (Ventilation Volume Adjustment Process 2) Fig. 14 is a flowchart (2) illustrating an example of ventilation volume adjustment process according to Example 4. Note that detailed description of processes similar to the ventilation volume adjustment processes described in Figs. 6 and 12 will be omitted here.

[0124] In step S1401, the control unit 102 acquires the CO2 concentration (carbon dioxide concentration) in the target area 2. Here, for example, as shown in Fig. 13 , one CO2 sensor 12 is installed in the target area 2, and the control unit 102 adjusts the ventilation volume of the ventilators 11a, 11b, and 11c installed in the target area 2.

[0125] Preferably, the control unit 102 acquires CO2 concentration data 111 of the target area 2 measured by the CO2 sensor 12 at a first time interval (e.g., 1-minute intervals), and sets the moving average of the CO2 concentration for a predetermined period (e.g., from the current time to 10 minutes ago) as the CO2 concentration of the target area 2.

[0126] In step S1402, the control unit 102 determines the ventilation volumes of the ventilation devices 11a, 11b, and 11c based on the current value of the CO 2 concentration in the target area 2 and the change in the CO 2 concentration in the target area 2 over time.

[0127] Preferably, the control unit 102 executes a ventilation rate determination process to determine the ventilation rates of the ventilators 11a, 11b, and 11c at second time intervals (e.g., five-minute intervals) longer than the first time intervals, based on the CO2 concentrations in the target area 2 acquired at first time intervals (e.g., one-minute intervals). As an example, the control unit 102 may control the ventilators 11a, 11b, and 11c to have the same ventilation rate.

[0128] As another example, the ventilation devices 11a, 11b, and 11c may be weighted in advance based on, for example, locations where people tend to gather or locations where carbon dioxide tends to accumulate, and the ventilation rates of the ventilation devices 11a, 11b, and 11c may be controlled to be different. In this case, the control unit 102 may apply the processing described in Examples 1 to 3 to determine the ventilation rate of the ventilation device 11b that is closer to the CO2 sensor 12, and then determine the ventilation rates of the ventilation devices 11a and 11c based on the determined ventilation rate of the ventilation device 11b and the weights of the ventilation devices 11a, 11b, and 11c.

[0129] In step S1403, the control unit 102 determines whether the ventilation volume of the ventilators 11a, 11b, and 11c has been changed. If the ventilation volume has been changed, the control unit 102 proceeds to step S1404. On the other hand, if the ventilation volume has not been changed, the control unit 102 ends the process of FIG. 12.

[0130] In step S1404, the control unit 102 instructs the ventilation device 11, of the ventilation devices 11a, 11b, and 11c, whose ventilation volume has been changed, to change the ventilation volume.

[0131] In addition, if two or more CO2 sensors 12 are installed in the target area 2, the ventilation devices 11 corresponding to each CO2 sensor 12 are grouped in advance for each CO2 sensor 12, and the control unit 102 executes the processing of Figure 14 for each group.

[0132] <Regarding Effects> FIG. 15 is a diagram for explaining the effects of the air conditioning system 1 according to this embodiment. In a graph 1500 in FIG. 15 , the horizontal axis represents the number of people in the target area 2, and the vertical axis represents the ventilation volume. The ventilation volume is the sum of the ventilation volumes of the multiple ventilation devices 11, with level 4 corresponding to the sum of the ventilation volumes when the ventilation volumes of all the ventilation devices 11 are set to "strong," and level 3 corresponding to the sum of the ventilation volumes when the ventilation volumes of all the ventilation devices 11 are set to "weak." Furthermore, level 2 corresponds to the sum of the ventilation volumes when a mixture of ventilation devices 11 with "weak" ventilation volumes and ventilation devices 11 with "stopped" ventilation volumes is present, and level 1 corresponds to the sum of the ventilation volumes when all the ventilation devices 11 are "stopped."

[0133] In graph 1500, the state of number of people (1) is a state in which the target area 2 is close to capacity, the ventilation volume is level 4 and the CO2 concentration in the target area 2 is near 1000 ppm, and the ventilation volume is level 3 and the CO2 concentration in the target area 2 is above 1000 ppm. The state of number of people (2) is a state in which the number of people in the target area 2 is less than capacity, the ventilation volume is level 4 and the CO2 concentration in the target area 2 is approximately 800 ppm to 1000 ppm, and the CO2 concentration in the target area 2 is above 850 ppm but below 1000 ppm at level 3. The state of number of people (3) is a state in which the number of people in the target area 2 is small, the ventilation volume is level 3 and the CO2 concentration in the target area 2 is below 850 ppm, and the CO2 concentration in the target area 2 is above 1000 ppm at level 1. The state where the number of people is (4) is a state where the number of people in the target area 2 is even smaller, the ventilation volume is at level 1, and the CO2 concentration in the target area 2 is greater than 700 ppm and less than 1000 ppm.

[0134] The first line 1501 represents the relationship between the number of people and the ventilation rate at which the CO2 concentration reaches 1000 ppm, the second line 1502 represents the relationship between the number of people and the ventilation rate at which the CO2 concentration reaches 850 ppm, and the third line 1503 represents the relationship between the number of people and the ventilation rate at which the CO2 concentration reaches 700 ppm.

[0135] Furthermore, the line of threshold control 1511 indicates control in which the ventilation volume is set to level 3 when the CO2 concentration in target area 2 is between 700 ppm and 850 ppm, to level 4 when it exceeds 850 ppm, and to level 1 when it is 700 ppm or less. The line of this embodiment 1511 indicates control of the ventilation volume of all ventilation devices 11 according to this embodiment.

[0136] In the state (1), the threshold control 1511 and the present embodiment 1512 both set the ventilation volume to level 4 (the ventilation volumes of all the ventilation devices 11 are "strong").

[0137] When the number of people in target area 2 decreases and the area transitions from state (1) to state (2), in this embodiment 1512, the ventilation volume is switched from level 4 to level 3 (the ventilation volume of all ventilators 11 is set to "weak") based on the current value of the CO2 concentration and its change over time. Meanwhile, in threshold control 1511, ventilation continues at the ventilation volume of level 4 until the CO2 concentration in target area 2 falls to 850 ppm or less.

[0138] If the number of people in the target area 2 further decreases, in this embodiment 1512, the ventilation rate can be further reduced by one level based on the current value of the CO2 concentration and its change over time. For example, in the example of Fig. 15, the air conditioning system 1 changes the ventilation rate from level 3 to level 2 (a mixture of ventilators 11 with ventilation rates set to "weak" and ventilators 11 with ventilation rates set to "stopped").

[0139] If the number of people in target area 2 decreases further and the state transitions from (2) to (3), threshold control 1511 switches the ventilation volume of all ventilation devices 11 from level 4 to level 3.

[0140] If the number of people in target area 2 further decreases and the state transitions from (3) to (4), in this embodiment 1512, the ventilation volume of all ventilation devices 11 can be changed to level 1 (the operation of all ventilation devices 11 can be stopped) based on the current value of the CO2 concentration and the change over time. On the other hand, in threshold control 1511, ventilation continues at the ventilation volume level 3 until the CO2 concentration in target area 2 falls to 700 ppm or less.

[0141] As described above, according to this embodiment, ventilation can be performed for the minimum time and amount necessary so long as the carbon dioxide concentration in the space to be ventilated does not exceed a predetermined value. Therefore, according to this embodiment, the ventilation volume of the air conditioning system 1 can be reduced. Furthermore, by reducing the ventilation volume, the load on the air conditioner 13 of the air conditioning system 1 can also be reduced.

[0142] <Summary> The air conditioning system 1 according to the present disclosure is an air conditioning system 1 including a ventilation device 11 and a control unit 102 that controls the ventilation device 11, and the control unit 102 acquires the CO2 concentration (carbon dioxide concentration) of the target area 2 that is the target of ventilation by the ventilation device 11, and adjusts the ventilation volume of the ventilation device 11 based on the current value of the CO2 concentration and the change in the CO2 concentration over time.

[0143] According to the air conditioning system 1, the air conditioning system 1 including the ventilation device 11 can perform ventilation for the minimum required time and amount within a range in which the CO2 concentration in the target area 2 to be ventilated does not exceed a predetermined value.

[0144] Preferably, the control unit 102 adjusts the ventilation volume of the ventilation device 11 using the current value of the CO2 concentration in the target area 2, a predetermined value that is a predetermined CO2 concentration, and the change over time of the CO2 concentration in the target area 2. In this way, the control unit 102 can use information on the change over time of the CO2 concentration in the target area 2 to suppress the ventilation volume while preventing the CO2 concentration in the target area 2 from reaching the predetermined concentration.

[0145] Preferably, the control unit 102 adjusts the ventilation volume of the ventilation device 11 using the difference between the current value of the CO2 concentration in the target area 2 and a predetermined value that is a predetermined CO2 concentration, and the change over time in the CO2 concentration in the target area 2. In this way, the control unit 102 can use information on the difference between the current value of the CO2 concentration in the target area 2 and the predetermined value that is the predetermined CO2 concentration to suppress the ventilation volume while preventing the CO2 concentration in the target area 2 from reaching the predetermined concentration.

[0146] Preferably, the control unit 102 calculates the time required for the CO2 concentration in the target area 2 to reach a predetermined value based on the current value of the CO2 concentration in the target area 2 and the change over time in the CO2 concentration in the target area 2, and adjusts the ventilation volume of the ventilation device 11 based on the calculated time required for the CO2 concentration to reach a predetermined value. In this way, the control unit 102 can suppress the ventilation volume while preventing the CO2 concentration in the target area 2 from reaching the predetermined concentration by using information on the time required for the CO2 concentration in the target area 2 to reach a predetermined value.

[0147] Preferably, the control unit 102 increases the ventilation volume of the ventilation device 11 by a first increase amount when the current value of the CO2 concentration in the target area 2 is smaller than a predetermined first predetermined value of the CO2 concentration and the time required for the CO2 concentration in the target area 2 to reach the first predetermined value is within a first time.

[0148] Preferably, when the arrival time is within a second time that is shorter than the first time, the control unit 102 increases the ventilation volume of the ventilation device 11 by a second increase amount that is greater than the first increase amount. This allows the air conditioning system 1 to suppress the ventilation volume while preventing the CO2 concentration in the target area 2 from exceeding the first predetermined value, even when the CO2 concentration in the target area 2 is increasing at a high rate.

[0149] Preferably, the control unit 102 reduces the ventilation volume of the ventilation device 11 by a first reduction amount when the current value of the CO2 concentration in the target area 2 is greater than a predetermined second predetermined value of the CO2 concentration and the time required for the CO2 concentration in the target area 2 to reach the second predetermined value is within a third time.

[0150] Preferably, when the time it takes for the CO2 concentration in the target area 2 to reach the second predetermined value is within a fourth time that is shorter than the third time, the control unit 102 reduces the ventilation rate of the ventilation device 11 by a second reduction amount that is greater than the first reduction amount, or stops operation of the ventilation device 11. This allows the air conditioning system 1 to suppress the ventilation rate when the rate of decrease of the CO2 concentration in the target area 2 is fast.

[0151] Preferably, the control unit 102 stops the operation of the ventilation device 11 when the current value of the CO2 concentration in the target area 2 is equal to or lower than a predetermined threshold value of the CO2 concentration that has been determined in advance.

[0152] Preferably, the air conditioning system 1 includes a plurality of ventilation devices 11, and the control unit 102 adjusts the ventilation volume of the plurality of ventilation devices based on the current value of the carbon dioxide concentration and the change in the carbon dioxide concentration over time.

[0153] Preferably, the control unit 102 determines the ventilation volume of the ventilation device 11 at a time interval longer than the time interval at which the CO 2 concentration in the target area 2 is measured.

[0154] Preferably, the control unit 102 smooths the acquired CO2 concentration in the target area 2 to calculate the time change in the CO2 concentration in the target area 2. This allows the air conditioning system 1 to reduce the adverse effects of fluctuations in the CO2 concentration carbon dioxide concentration data in the target area 2.

[0155] Preferably, the air conditioning system 1 includes a ventilation device 11 and a communication device 10 capable of communicating with the ventilation device 11 , and the communication device 10 has a control unit 102 .

[0156] The ventilation control method of the present disclosure is an air conditioning system 1 including a ventilation device 11 and a control unit 102 that controls the ventilation device 11, in which the control unit 102 acquires the CO2 concentration of a target area 2 that is the target of ventilation by the ventilation device 11, and adjusts the ventilation volume of the ventilation device 11 based on the current value of the CO2 concentration of the target area 2 and the change in the CO2 concentration of the target area 2 over time.

[0157] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0158] This application claims priority based on Japanese Patent Application No. 2023-115680, filed with the Japan Patent Office on July 14, 2023, the entire contents of which are incorporated by reference into this international application.

[0159] REFERENCE SIGNS LIST 1 Air conditioning system 2 Target area (space to be ventilated) 10 Communication device 11, 11a, 11b, 11c Ventilation device 12 CO2 sensor 100 Management server 102 Control unit 500 Computer N Communication network

Claims

1. An air conditioning system including a ventilation device and a control unit that controls the ventilation device, wherein the control unit acquires a carbon dioxide concentration in a space that is to be ventilated by the ventilation device, and adjusts the ventilation volume of the ventilation device based on a current value of the carbon dioxide concentration and a change in the carbon dioxide concentration over time.

2. The air conditioning system of claim 1, wherein the control unit adjusts the ventilation volume of the ventilation device using a current value of the carbon dioxide concentration, a predetermined value that is a predetermined carbon dioxide concentration, and a change in the carbon dioxide concentration over time.

3. The air conditioning system of claim 1, wherein the control unit adjusts the ventilation volume of the ventilation device using the difference between the current value of the carbon dioxide concentration and the predetermined value of the carbon dioxide concentration and the change in the carbon dioxide concentration over time.

4. The air conditioning system of claim 1, wherein the control unit calculates a time required for the carbon dioxide concentration to reach a predetermined value, which is a predetermined carbon dioxide concentration, from a current value of the carbon dioxide concentration and a change in the carbon dioxide concentration over time, and adjusts the ventilation volume of the ventilation device based on the time required to reach the predetermined value.

5. The air conditioning system of claim 1, wherein the control unit increases the ventilation volume of the ventilation device by a first increase when the current value of the carbon dioxide concentration is smaller than a first predetermined value of the carbon dioxide concentration and the time required for the carbon dioxide concentration to reach the first predetermined value is within a first time.

6. An air conditioning system as described in claim 5, wherein the control unit increases the ventilation volume of the ventilation device by a second increase amount greater than the first increase amount when the arrival time is within a second time shorter than the first time.

7. The air conditioning system of claim 1, wherein the control unit reduces the ventilation volume of the ventilation device by a first reduction amount when the current value of the carbon dioxide concentration is greater than a second predetermined value of the carbon dioxide concentration set in advance and the time it takes for the carbon dioxide concentration to reach the second predetermined value is within a third time.

8. The air conditioning system of claim 7, wherein the control unit reduces the ventilation volume of the ventilation device by a second reduction amount greater than the first reduction amount, or stops operation of the ventilation device, when the arrival time is within a fourth time shorter than the third time.

9. An air conditioning system as claimed in any one of claims 1 to 8, wherein the control unit stops operation of the ventilation device when the current value of the carbon dioxide concentration is equal to or lower than a predetermined threshold value of the carbon dioxide concentration.

10. An air conditioning system as described in any one of claims 1 to 8, wherein the air conditioning system includes a plurality of ventilation devices, and the control unit adjusts the ventilation volume of the plurality of ventilation devices based on a current value of the carbon dioxide concentration and a change in the carbon dioxide concentration over time.

11. An air conditioning system according to any one of claims 1 to 8, wherein the control unit is configured such that the time interval for determining the ventilation volume is longer than the time interval for measuring the carbon dioxide concentration.

12. An air conditioning system according to any one of claims 1 to 8, wherein the control unit smoothes the acquired carbon dioxide concentration to calculate the change in the carbon dioxide concentration over time.

13. The air conditioning system according to any one of claims 1 to 8, comprising: the ventilation device; and a communication device capable of communicating with the ventilation device, the communication device having the control unit.

14. A ventilation control method in an air conditioning system including a ventilation device and a control unit that controls the ventilation device, wherein the control unit acquires a carbon dioxide concentration in a space that is to be ventilated by the ventilation device, and adjusts the ventilation volume of the ventilation device based on a current value of the carbon dioxide concentration and a change in the carbon dioxide concentration over time.

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