JP7799829B2 - Ventilation system and air conditioning system equipped with the same - Google Patents

Description

The present disclosure relates to a ventilation system that ventilates a room based on _CO2 concentration and an air conditioning system including the same.

Conventional technology initiates ventilation when the _CO2 concentration in a room is equal to or greater than a preset concentration threshold, or when the rate of increase in _CO2 concentration is equal to or greater than a concentration change rate threshold (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2000-88320

In the technology of Patent Document 1, the concentration threshold is set to a ventilation standard value that requires ventilation. Therefore, ventilation is initiated only after the _CO2 concentration reaches the ventilation standard value. Given that ventilation control requires maintaining the _CO2 concentration in the room at or below the ventilation standard value, there is room for improvement. Furthermore, in the technology of Patent Document 1, if the _CO2 concentration increases sharply due to a sudden increase in the number of people in the same room, ventilation is initiated when the rate of increase in _CO2 concentration exceeds the concentration change rate threshold. Therefore, in the technology of Patent Document 1, _ventilation is initiated when the rate of increase in CO2 concentration exceeds the concentration change rate threshold, even if the _CO2 concentration increases only temporarily and does not exceed the ventilation standard value. In other words, the technology of Patent Document 1 has the problem of unnecessary ventilation.

The present disclosure aims to solve the above-mentioned problems and to provide a ventilation system capable of performing appropriate ventilation according to the _CO2 concentration in the room, and an air conditioning system equipped with the same.

The ventilation system according to the present disclosure includes a _CO2 concentration detection device that detects the _CO2 concentration in a room, a ventilation device that ventilates the room, and a ventilation control device that has a first control mode that puts the ventilation device into operation when the _CO2 concentration is equal to or greater than a first concentration threshold that is lower than a ventilation reference value that is a reference value that requires ventilation, and a second control mode that puts the ventilation device into operation when it is estimated that the _{CO2 concentration will exceed the ventilation reference value based on the CO2 concentration} and the rate of increase of the _CO2 concentration , and the second control mode is a mode that puts the ventilation device into operation when the _CO2 concentration is equal to or greater than a second concentration threshold that is lower than the first concentration threshold and the rate of change of the CO2 _{concentration} is equal to or greater than a predetermined concentration change rate threshold .

The air conditioning system of the present disclosure is equipped with the above-mentioned ventilation system.

The ventilation system and air conditioning system according to the present disclosure can stably maintain the indoor _CO2 concentration at or below the ventilation standard value by operating in the first control mode compared to when the first concentration threshold is set to the ventilation standard value. Furthermore, the ventilation system can avoid unnecessary ventilation in the event of a temporary increase in _CO2 concentration that does not exceed the ventilation standard value by operating in the second control mode. In this way, the ventilation system can provide appropriate ventilation appropriate to the indoor _CO2 concentration situation by using the first control mode and the second control mode.

FIG. 1 is an explanatory diagram of a usage pattern of a ventilation system according to a first embodiment. FIG. 1 is a block diagram of a ventilation system according to a first embodiment. 4 is a control flowchart in the ventilation system according to the first embodiment. 4A and 4B are diagrams showing changes in CO ₂ concentration and changes in the rate of change of CO ₂ concentration in the ventilation system according to the first embodiment. FIG. 3 is a state transition diagram of the ventilation device in the ventilation system according to the first embodiment. FIG. 10 is an explanatory diagram of a usage pattern of a modified example of the ventilation system according to the first embodiment. FIG. 10 is a diagram showing the configuration of an air conditioning system according to a second embodiment.

Embodiment 1.
1 is an explanatory diagram of a usage pattern of a ventilation system 10 according to embodiment 1. The ventilation system 10 of embodiment 1 includes a ventilation control device 1, a _CO2 concentration detection device 2 that detects the _CO2 concentration in a room, and a ventilation device 3 that ventilates the room in which the _CO2 concentration detection device 2 is installed.

The ventilation control device 1 is a device that controls the ventilation device 3 based on the detection results of the _CO2 concentration detection device 2. The _CO2 concentration detection device 2 is composed of a concentration detection sensor, and is a device that detects the _CO2 concentration at regular intervals (for example, every minute) and transmits the detection results to the ventilation control device 1.

The ventilation device 3 is a device capable of ventilating a room and is equipped with an exhaust fan that expels indoor air to the outside and an intake fan that draws outdoor air into the room. The configuration of the ventilation device 3 is not limited to a configuration equipped with an exhaust fan and an intake fan, as long as it is a device capable of ventilating a room. The ventilation device 3 also has an operation switch 3a, which the user can operate to manually switch the ventilation device 3 on and off, or the ventilation control device 1 can automatically control the operation and stopping of the ventilation device 3. The operation switch 3a is not limited to being equipped on the ventilation device 3, and may also be configured so that the operation unit 13 (see Figure 2) of the ventilation control device 1, described below, has the same function as the operation switch 3a.

Figure 2 is a block diagram of the ventilation system 10 according to embodiment 1. The ventilation control device 1 includes a control unit 11, a memory unit 12, and an operation unit 13. The control unit 11 is configured as a microprocessor unit and includes a CPU, RAM, ROM, etc., and control programs, etc. are stored in the ROM. The control unit 11 controls the entire ventilation system in accordance with the control program. The control unit 11 is not limited to a microprocessor unit. For example, the control unit 11 may be configured as an updatable component such as firmware. The control unit 11 may also be a program module that is executed in response to commands from a CPU, etc. (not shown).

The memory unit 12 stores various thresholds and the like, which will be described later. The memory unit 12 includes ROM, RAM, and the like. The operation unit 13 is a unit where user input is performed. The operation unit 13 is composed of, for example, at least a button, a touch panel, or a display panel, and is a unit that accepts user instructions and outputs the content of the instructions to the control unit 11. The operation unit 13 has a setting unit 13a that sets the priority between a manual operation mode and an automatic operation mode. The manual operation mode is a mode in which the ventilation device 3 is controlled based on the operation of the operation switch 3a. The automatic operation mode is a mode in which the ventilation device 3 is controlled based on _{the CO2} concentration and the rate of increase of the _CO2 concentration detected by the CO2 concentration detection device 2. The ventilation control device 1 selects either the manual operation mode or the automatic operation mode according to the priority set in the setting unit 13a and controls the ventilation device 3. The operation of the ventilation system 10 will be described below assuming that the automatic operation mode is selected.

The ventilation control device 1 further includes an inter- _CO2 concentration detecting device communication unit 14 that communicates with the _CO2 concentration detecting devices 2, a ventilation device communication unit 15 that communicates with the ventilation devices 3, and an external device communication unit 16 that communicates with external devices 4 such as smartphones and tablets. Communication 5a between the _inter-CO2 concentration detecting device communication unit 14 and the _CO2 concentration detecting devices 2, communication 5b between the ventilation device communication unit 15 and the ventilation device 3, and communication 5c between the external device communication unit 16 and the external device 4 are performed wirelessly or via a cable. The ventilation control device 1 is configured to be incorporated into, for example, a remote control or the like.

The _CO2 concentration detecting device 2 includes a _CO2 concentration detecting unit 22 configured with a _CO2 sensor, and an inter-ventilation control device communication unit 21 that transmits the detection result detected by the _CO2 concentration detecting unit 22 to the inter- _CO2 concentration detecting device communication unit 14 of the ventilation control device 1. Note that, although an example of the _CO2 concentration detecting device 2 being an independent device that is installed separately from the ventilation control device 1 and the ventilation device 3 is shown in FIG. 1 , it may also be provided in the ventilation control device 1 or the ventilation device 3. The installation location of _{the CO2} concentration detecting device 2 is not particularly limited.

Here, ventilation control in embodiment 1 will be described. In ventilation control in embodiment 1, a first concentration threshold (e.g., 900 ppm) lower than a ventilation reference value (e.g., 1000 ppm), which is a reference value that requires ventilation, is preset. Furthermore, in ventilation control in embodiment 1, the following _two index values are preset to avoid unnecessary ventilation in the event of a temporary increase in CO2 concentration that does not exceed the ventilation reference value. That is, in addition to the first concentration threshold, the ventilation control device 1 is set with a second concentration threshold (e.g., 800 ppm) that is even lower than the first concentration threshold, and a concentration change rate threshold (e.g., 50 ppm/min), which is a threshold for the rate of change of the _CO2 concentration.

The ventilation control device 1 has a first control mode and a second control mode. The first control mode is a mode in which the ventilation device 3 is controlled based only on the _CO2 concentration. Specifically, the first control mode is a mode in which the ventilation device 3 is put into operation when the _CO2 concentration is equal to or greater than a first concentration threshold. The second control mode is a mode in which the ventilation device 3 is put into operation when it is estimated that the _CO2 concentration will exceed the ventilation reference value based on the _CO2 concentration and the rate of increase of the _CO2 concentration. Specifically, the second control mode is a mode in which the ventilation device 3 is put into operation when the _CO2 concentration is equal to or greater than a second concentration threshold and the rate of change of the _CO2 concentration is equal to or greater than a concentration change rate threshold. The ventilation control device 1 has the first control mode and the second control mode, and operates in the first control mode or the second control mode based on the detection result of the _CO2 concentration detection device 2.

The first concentration threshold, second concentration threshold, and concentration change rate threshold are stored in the memory unit 12. The concentration change rate threshold is determined, for example, as in (1) or (2) below and stored in the memory unit 12. The concentration change rate threshold may be determined by the user and input to the operation unit 13 and stored in the memory unit 12, or it may be determined by the control unit 11 or external device 4 and stored in the memory unit 12.

(1) The concentration change rate threshold is determined according to the size of the room. In this case, for example, the concentration change rate threshold corresponding to the size of the room is stored in advance in the storage unit 12, and when the user inputs the size of the room into the operation unit 13 during construction, the corresponding concentration change rate threshold is stored in the storage unit 12.
(2) The concentration change rate threshold is determined based on the conditions under which the _CO2 concentration previously exceeded the ventilation standard value. Specifically, for example, the concentration change rate threshold is determined as follows from previously logged _CO2 concentration data. The control unit 11 or the external device 4 calculates the maximum value of the rate of change of the _CO2 concentration from the time the _CO2 concentration becomes equal to or greater than the second concentration threshold to the time it reaches the first concentration threshold, and the maximum value of the rate of change of the _CO2 concentration from the time the _CO2 concentration becomes equal to or greater than the first concentration threshold to the time it reaches the ventilation standard value. If the former is greater, the control unit 11 or the external device 4 determines the maximum value as the new concentration change rate threshold.

3 is a control flowchart of the ventilation system 10 according to the first embodiment. When the _CO2 concentration detected by the _CO2 concentration detection device 2 is equal to or greater than the first concentration threshold (step S1: YES), the ventilation control device 1 drives the ventilation device 3 to operate (step S2). This step S2 is performed when the _CO2 concentration is equal to or greater than the first concentration threshold, and therefore corresponds to operation in the first control mode. When the ventilation control device 1 determines that the _CO2 concentration detected by the _CO2 concentration detection device 2 is not equal to or greater than the first concentration threshold (step S1: NO), it then determines whether the _CO2 concentration is equal to or greater than the second concentration threshold (step S3).

If the ventilation control device 1 determines that the _CO2 concentration is not equal to or greater than the second concentration threshold (step S3: NO), it stops the ventilation device 3 (step S4). On the other hand, if the ventilation control device 1 determines in step S3 that the _CO2 concentration is equal to or greater than the second concentration threshold (step S3: YES), it then determines whether the _CO2 concentration change rate is equal to or greater than a preset concentration change rate threshold (step S5). _{The CO2} concentration change rate is, for example, the _CO2 concentration change rate over the past minute, and is calculated by subtracting the _CO2 concentration from one minute ago from the current _CO2 concentration. _{The CO2} concentration change rate is calculated by the control unit 11 of the ventilation control device 1 and stored in the memory unit 12. If the ventilation control device 1 determines in step S5 that the _CO2 concentration change rate is not equal to or greater than the concentration change rate threshold (step S5: NO), it stops the ventilation device 3 (step S4).

On the other hand, if the ventilation control device 1 determines in step S5 that the _CO2 concentration change rate is equal to or greater than the concentration change rate threshold (step S5: YES), it operates the ventilation device 3 (step S6). This step S6 is performed when the second concentration threshold≦ _CO2 concentration<first concentration threshold and the _CO2 concentration change rate≧concentration change rate threshold, and therefore corresponds to operation in the second control mode.

The ventilation control device 1 repeatedly performs the above steps S1 to S6 at each control timing, which is, for example, one-minute intervals. The "Ventilation device: operating state" in step S2 and the "Ventilation device: operating state" in step S6 mean that if the ventilation device 3 was not operating at the previous control timing, the ventilation device 3 will start operating, and if the ventilation device 3 was operating at the previous control timing, the ventilation device 3 will continue operating. Furthermore, the "Ventilation device: stopped state" in step S4 means that if the ventilation device 3 was operating at the previous control timing, the ventilation device 3 will stop operating, and if the ventilation device 3 was stopped at the previous control timing, the operation will continue to be stopped.

FIG. 4 is a diagram showing changes in _CO2 concentration and changes in the _CO2 concentration change rate in the ventilation system 10 according to embodiment 1. FIG. 4 also shows state changes between the operating state and the stopped state of the ventilation device 3. FIG. 4(a) is a graph showing changes in _CO2 concentration [ppm]. FIG. 4(b) is a graph showing changes in the _CO2 concentration change rate [ppm/min]. In FIG. 4(b), a positive value for the _CO2 concentration change rate indicates an increase in _CO2 concentration, and a negative value for the _CO2 concentration change rate indicates a decrease in _CO2 concentration. FIG. 4(c) is a timing diagram showing changes between the operating state and the stopped state of the ventilation device 3. FIG. 5 is a state transition diagram of the ventilation device 3 in the ventilation system 10 according to embodiment 1. Please refer to the description of FIG. 4 below for the state transition of the ventilation device 3 in FIG. 5 as appropriate.

Between time t0 and time t1, the _CO2 concentration is less than the second concentration threshold as shown in (a), and the ventilation device 3 is in a stopped state as shown in (c).

At time t1, as shown in (a), the _CO2 concentration becomes equal to or greater than the second concentration threshold, and as shown in (b), the _CO2 concentration change rate becomes equal to or greater than the concentration change rate threshold (here, 50 ppm/min), so the ventilation device 3 changes from a stopped state to an operating state (second control mode) and starts ventilating the room.

At time t2, as shown in (a), the _CO2 concentration becomes equal to or higher than the first concentration threshold, and the ventilation device 3 continues to operate. Note that the operation mode has been changed from the second control mode to the first control mode.

Between time t2 and time t3, as shown in (a), the _CO2 concentration is equal to or higher than the first concentration threshold, so the ventilation device 3 continues to operate (first control mode).

At time t3, the _CO2 concentration falls below the first concentration threshold, as shown in (a). Therefore, at time t3, the ventilation device 3 changes from an operating state (first control mode) to a stopped state. Note that, at time t3, the _CO2 concentration is equal to or greater than the second concentration threshold, but the _CO2 concentration change rate is less than the concentration change rate threshold. Therefore, the ventilation control device 1 does not transition from an operating state (first control mode) to an operating state (second control mode), and the ventilation device 3 is in a stopped state. In other words, if the _CO2 concentration falls below the first concentration threshold while operating in the first control mode, the ventilation device 3 changes from an operating state (first control mode) to a stopped state. When the ventilation device 3 is in a stopped state at time t3, the _CO2 concentration changes from a decreasing to an increasing state, as shown in (a).

At time t4, as shown in (a), the _CO2 concentration again becomes equal to or greater than the first concentration threshold, causing the ventilation device 3 to change from the stopped state to the operating state (first control mode) as shown in (c), and start ventilating the room again. As a result, the _CO2 concentration decreases.

At time t5, as shown in (a), the _CO2 concentration falls below the first concentration threshold, and the ventilation device 3 changes from an operating state to a stopped state.

Here, when the _CO2 concentration change rate is less than the concentration change rate threshold, the ventilation control device 1 controls the switching between the operating state and the stopped state of the ventilation device 3 (hereinafter referred to as ON/OFF) using a first concentration threshold as a judgment criterion. Specifically, this ON/OFF control corresponds to the period from time t3 to time t5 in FIG. 4. In this way, when ON/OFF control is performed using the first concentration threshold as a judgment criterion, there is a possibility that the operation of the ventilation device 3 will undergo hunting, in which the operation is repeatedly turned ON/OFF in a short period of time. For this reason, the ventilation control device 1 may perform the following control.

The ventilation control device 1 uses the second concentration threshold instead of the first concentration threshold as the threshold for determining whether to switch the ventilation device 3 from the operating state to the stopped state. Specifically, referring to the example of FIG. 4 , the ventilation control device 1 switches the ventilation device 3 from the operating state to the stopped state at time t5, for example. However, instead of switching at time t5, the ventilation device 3 is switched from the operating state to the stopped state after time t5, when the _CO2 concentration falls below the second concentration threshold. The subsequent operation is the same as described above. However, even if the _CO2 concentration rises above the second concentration threshold immediately after falling below the second concentration threshold due to an increase in the number of people in the room, for example, the _CO2 increase rate is unlikely to exceed the concentration change rate threshold, given that the _CO2 concentration had been declining until then. Therefore, the ventilation device 3 is not repeatedly turned on and off in a short period of time.

As described above, the ventilation control device 1 has a first control mode and starts ventilation when the _CO2 concentration is equal to or higher than the first concentration threshold, which is lower than the ventilation reference value. Therefore, the ventilation system 10 can stably keep the _CO2 concentration in the room at or below the ventilation reference value, compared to when the first concentration threshold is set to the ventilation reference value.

Furthermore, if the ventilation control device 1 only has the first control mode and does not have the second control mode, the ventilation device 3 will enter an operating state at time t2 when the _CO2 concentration becomes equal to or greater than the first concentration threshold. When the ventilation device 3 enters an operating state at time t2, the rate of change of the _CO2 concentration in the room will decrease, but ventilation will not be able to keep up, and the _CO2 concentration will exceed the ventilation standard value, as shown by dotted line A in (a).

In contrast, the ventilation control device 1 of embodiment 1 has a second control mode, and determines at time t1, before time t2, that there is a possibility that the indoor _CO2 concentration will exceed the ventilation standard value, and operates the ventilation device 3. This allows the ventilation system 10 to prevent the _CO2 concentration from exceeding the ventilation standard value, as shown in (a).

Furthermore, the ventilation system 10 does not simply turn on the ventilation device 3 to start ventilation when the _CO2 concentration change rate exceeds the concentration change rate threshold, but also starts ventilation when the _CO2 concentration exceeds a second concentration threshold. This allows the ventilation system 10 to avoid unnecessary ventilation when the indoor _CO2 concentration temporarily increases but does not exceed the ventilation standard value. As a result, the ventilation system 10 can reduce unnecessary changes in room temperature and unnecessary power consumption caused by operating the ventilation device 3 at unnecessary times.

Here, a supplementary explanation will be given regarding FIG. 5 . In FIG. 5 , the arc-shaped arrows indicate that the corresponding operating states, i.e., the "operating state (first control mode),""operating state (second control mode)," and "stopped state," will continue, and the conditions for continuation are written in the balloons. Specifically, the "operating state (first control mode)" continues when " _CO2 concentration ≧ first concentration threshold." Furthermore, the "operating state (second control mode)" continues when "second concentration threshold ≦ _CO2 concentration < first concentration threshold, and _CO2 concentration change rate ≧ concentration change rate threshold." Furthermore, the "stopped state" continues when " _CO2 concentration < second concentration threshold, or (second concentration threshold ≦ _CO2 concentration < first concentration threshold, and concentration change rate threshold < _CO2 concentration change rate)."

The ventilation system 10 may be modified as follows: The ventilation system 10 may be appropriately combined with the following modifications.

In the above, the ventilation device 3 is assumed to have a constant ventilation volume, but it may also be one in which the ventilation volume can be changed by changing the fan rotation speed. If the ventilation device 3 is one in which the ventilation volume can be changed, the ventilation system 10 may change its operation as follows.

(1) The ventilation control device 1 sets the fan rotation speed to a first rotation speed in the first control mode and to a second rotation speed lower than the first rotation speed in the second control mode. Specifically, the first rotation speed is set to, for example, the maximum rotation speed of the device. That is, the ventilation control device 1 provides gentle ventilation when the _CO2 concentration is equal to or greater than the second concentration threshold but less than the first concentration threshold, and maximizes the ventilation volume when the _CO2 concentration is equal to or greater than the first concentration threshold.
(2) In the case of (1) above, the ventilation control device 1 separately sets a second concentration change threshold that is faster than the concentration change rate threshold. Then, in the second control mode, when the rate of increase of the _CO2 concentration is faster than the second concentration change threshold, the ventilation system 10 maximizes the ventilation volume even when the _CO2 concentration is equal to or greater than the second concentration threshold but less than the first concentration threshold, in the same way as when the CO2 concentration is equal to or greater than the first concentration threshold.

The ventilation control device 1 may correct the default first concentration threshold and second concentration threshold pre-set in the memory unit 12 according to the operating conditions as follows.

(1) The ventilation control device 1 acquires the number of people in the room, and if the number of people is equal to or greater than a preset number-of-people threshold, corrects the first and second concentration thresholds to lower them from the default values stored in the memory unit 12 so that the ventilation device 3 starts operating earlier. Furthermore, when the number of people detected by the number of people detection device 17 falls below the number-of-people threshold, the ventilation control device 1 restores the first and second concentration thresholds to their original values. The ventilation control device 1 may acquire the number of people in the room, for example, via wireless or wired communication from a human presence sensor 18 (see Figure 6 described below) separate from the ventilation system 10. An example of a separate human presence sensor is a pyroelectric sensor installed in an indoor unit (not shown) that air-conditions the room. The human presence sensor 18 may alternatively be, for example, an infrared sensor installed at the entrance to the room, which counts the number of people entering and exiting the room to acquire the number of people in the room.

(2) If the _CO2 increase rate reaches or exceeds a second concentration change threshold, which is faster than the concentration change rate threshold, before the _CO2 concentration reaches or exceeds the second concentration threshold, the ventilation control device 1 may temporarily lower the first concentration threshold and the second concentration threshold from their default values to start ventilation earlier.

(3) If the filter provided in the ventilation device 3 becomes clogged or the fan deteriorates, the ventilation volume of the ventilation device 3 will decrease even if the rotation speed remains the same. If the ventilation volume of the ventilation device 3 decreases, the _CO2 concentration may exceed the ventilation standard value even if the same control is performed by the ventilation control device 1. For example, if the _CO2 concentration exceeds the ventilation standard value even though the rate of increase of the _CO2 concentration has not increased, or if the _CO2 concentration exceeds the ventilation standard value even though there are not many people in the room, it can be assumed that the cause is a decrease in the ventilation volume.

When there is a decrease in ventilation volume due to deterioration of the ventilation device 3, the ventilation control device 1 lowers the first concentration threshold and the second concentration threshold below their default values so that ventilation begins earlier, and displays a message on the display device that ventilation is recommended. If the operation unit 13 is a display panel, the operation unit 13 may also function as the display device. The display device may also be configured as an indicator lamp such as an LED that lights up when ventilation is recommended.

Specific control involves the ventilation control device 1 correcting the first and second concentration thresholds to be lower than their default values when it detects a decrease in ventilation volume due to deterioration of the ventilation device 3. The ventilation control device 1 restores the first and second concentration thresholds to their original values when the decrease in ventilation volume due to deterioration of the ventilation device 3 is resolved. The situation where the decrease in ventilation volume due to deterioration of the ventilation device 3 is resolved corresponds to a user operation indicating that the filter has been cleaned, or a situation where there is sufficient ventilation and the filter is cleaned even without a user operation.

Detection of a decrease in ventilation volume due to deterioration of the ventilation device 3 may be performed, for example, by the ventilation control device 1 accumulating the operating time of the ventilation device 3 and detecting that the accumulated operating time exceeds a preset time as a decrease in ventilation volume due to deterioration of the ventilation device 3. This is intended to assume that if the ventilation device 3 has been operating for longer than the set time, it is natural that the filter will become clogged, and that a decrease in ventilation volume due to clogging is occurring. Furthermore, detection of a decrease in ventilation volume due to deterioration of the ventilation device 3 may be performed, for example, by a sensor that detects clogged filters.

The reduction amounts of the first and second density thresholds in (1), (2), and (3) above are not particularly limited and can be set arbitrarily. The reduction amounts of the first and second density thresholds may be set in advance, or may be input by the user via the operation unit 13.

In addition, there may be areas in a room where there are few people and areas where there are many people. In such cases, it is possible to perform the above control using the _CO2 concentration in the areas where there are many people. Therefore, the ventilation system 10 may have the configuration shown in Figure 6 below.

6 is an explanatory diagram of a usage form of a modified example of the ventilation system according to Embodiment 1. The ventilation system 10 includes a plurality of _CO2 concentration detecting devices 2. The _CO2 concentration detecting devices 2 are installed in a dispersed manner throughout the room. The ventilation control device 1 identifies, among the plurality of _CO2 concentration detecting devices 2, a _CO2 concentration detecting device 2 that is located near an area in the room where a large number of people are present, and performs the above-described control based on the detection results of the identified _CO2 concentration detecting device 2. A human presence sensor 18, separate from the ventilation system 10, is also installed in the room.

The human presence sensor 18 is composed of a pyroelectric sensor that detects infrared rays emitted from a heat source such as a person. Although not shown, the pyroelectric sensor has a sensor unit with multiple pyroelectric elements arranged in a vertical row. The pyroelectric sensor rotates and moves the sensor unit to scan the room and detect how many people are present in which area of the room. The detection results of the human presence sensor 18 are transmitted to the ventilation control device 1 via wireless or wired communication. Note that the human presence sensor 18 is not limited to a pyroelectric sensor, and can be any sensor that can identify the location and number of people in the room.

The ventilation system 10 identifies _CO2 concentration detection devices 2 located near areas with a large number of people in a room, for example, as follows. The ventilation system 10 identifies the location information of each CO2 concentration detection device 2 based on the wireless strength of wireless communication 5a. The ventilation control device 1 determines the number of people around each _CO2 concentration detection device 2 based on the location information of each _CO2 concentration detection device 2 identified based on the wireless strength and human detection information detected by the human presence sensor 18. The ventilation control device 1 identifies the _CO2 concentration detection device 2 located near the area with the largest number of people. The method of identifying _{the CO2} concentration detection device 2 located near the area with the largest number of people is not limited to the method based on the wireless strength described above. For example, the location information of each _CO2 concentration detection device 2 may be identified by determining the indoor location of each _CO2 concentration detection device in advance and identifying the location from the identification number of the _CO2 concentration detection device.

A ventilation system 10 of the first embodiment includes a _CO2 concentration detection device 2 that detects the _CO2 concentration in a room, and a ventilation device 3 that ventilates the room. The ventilation system 10 further includes a ventilation control device 1 that has a first control mode that operates the ventilation device 3 when the _CO2 concentration is equal to or higher than a _first concentration threshold that is lower than a _ventilation reference value that is a reference value requiring ventilation, and a second control mode that operates the ventilation device 3 when it is estimated that the CO2 concentration will exceed a predetermined ventilation reference value based on the _CO2 concentration and the rate of increase of the CO2 concentration. The ventilation control device 1 operates in the first control mode or the second control mode based on the _CO2 concentration and the rate of increase of the _CO2 concentration.

With the above configuration, the ventilation system 10 can stably maintain the indoor _CO2 concentration at or below the ventilation standard value by operating in the first control mode, compared to when the first concentration threshold is set to the ventilation standard value. Furthermore, the ventilation system 10 can avoid unnecessary ventilation when a temporary increase _{in CO2} concentration occurs that does not exceed the ventilation standard value by operating in the second control mode. In this way, the ventilation system 10 can provide appropriate ventilation that matches the indoor _CO2 concentration by appropriately controlling the ventilation timing.

The second control mode is a mode in which the ventilation device 3 is put into operation when the _CO2 concentration is equal to or higher than a second concentration threshold value that is lower than the first concentration threshold value and the rate of change of the _CO2 concentration is equal to or higher than a predetermined concentration change rate threshold value.

With the above configuration, the ventilation system 10 can avoid unnecessary ventilation when a temporary increase in CO ₂ concentration occurs such that the CO ₂ concentration does not exceed the ventilation standard value.

The ventilation control device 1 stops the ventilation device 3 when the _CO2 concentration is less than the second concentration threshold. Furthermore, the ventilation control device 1 changes the ventilation device 3 from an operating state to a stopped state when the _CO2 concentration falls below the first concentration threshold while operating in the first control mode.

With the above configuration, the ventilation system 10 can avoid unnecessary ventilation when the _CO2 concentration does not exceed the ventilation standard value.

The ventilation control device 1 is equipped with an operation unit 13 into which the user inputs the concentration change rate threshold, and the concentration change rate threshold is determined by the user inputting it into the operation unit 13.

With the above configuration, the ventilation system 10 can set the concentration change rate threshold by user input into the operation unit 13.

The ventilation system 10 is equipped with an operation switch 3a that switches the ventilation device 3 on and off, and the ventilation device 3 can be manually switched on and off by operating the operation switch 3a.

With the above configuration, the ventilation system 10 also allows the ventilation device 3 to be operated manually.

The ventilation system 10 includes a setting unit 13a that is operated by a user and that sets the priority between the manual operation mode and the automatic operation mode. The ventilation control device 1 controls the ventilation device 3 based on the _CO2 concentration and the rate of increase in the _CO2 concentration when the priority of the automatic operation mode is higher than the priority of the manual operation mode, and controls the ventilation device 3 based on the operation of the operation switch 3a when the priority of the manual operation mode is higher than the priority of the automatic operation mode.

With the above configuration, the ventilation system 10 allows the user to determine the priority between manual operation mode and automatic operation mode.

The ventilation control device 1 obtains the number of people in the room, and if the number of people is equal to or greater than a predetermined number of people threshold, it makes a correction to lower the first concentration threshold and the second concentration threshold, and if the number of people falls below the number of people threshold, it restores the first concentration threshold and the second concentration threshold to their original values.

With the above configuration, the ventilation system 10 can quickly put the ventilation device 3 into operation when the number of people in the room is equal to or greater than the occupancy threshold.

When the ventilation control device 1 detects a decrease in ventilation volume due to deterioration of the ventilation device 3, it lowers the first concentration threshold and the second concentration threshold, and when the decrease in ventilation volume due to deterioration of the ventilation device 3 is resolved, it restores the first concentration threshold and the second concentration threshold to their original values.

With the above configuration, the ventilation system 10 can prevent the CO ₂ concentration from exceeding the ventilation standard value when the ventilation device 3 deteriorates.

The ventilation system 10 is equipped with multiple _CO2 concentration detection devices 2, and the ventilation control device 1 identifies, from among the multiple _CO2 concentration detection devices 2, a _CO2 concentration detection device 2 that is located near an area in the room where there are many people, and controls the first control mode and the second control mode based on the detection results of the identified _CO2 concentration detection device 2.

With the above configuration, the ventilation system 10 can control the ventilation volume in the room based on the CO ₂ concentration in the area with the most people in the room.

Embodiment 2.
The second embodiment relates to an air conditioning system equipped with the ventilation system 10 of the first embodiment.

Figure 7 is a diagram showing the configuration of an air conditioning system 200 according to embodiment 2. The air conditioning system 200 comprises the ventilation system 10 of embodiment 1 and an air conditioner 100. The air conditioner 100 comprises an indoor unit 101 and an outdoor unit 102. The indoor unit 101 and the outdoor unit 102 are connected by connecting pipes 103 and 104. The air conditioner 100 conditions the air inside the room by circulating a refrigerant between the indoor unit 101 and the outdoor unit 102 via connecting pipes 103 and 104.

The air conditioning system 200 has a control device 1a that controls the entire air conditioning system. The control device 1a is configured to include the ventilation control device 1 of embodiment 1.

In the above-mentioned embodiment 1, the ventilation system 10 is configured to be used alone, but in embodiment 2, the ventilation system 10 is configured to be incorporated into the air conditioning system 200. In this way, the ventilation system 10 may be used alone or may be incorporated into the air conditioning system 200.

1 ventilation control device, 1a control device, 2 _CO2 concentration detection device, 3 ventilation device, 3a operation switch, 4 external device, 5a communication between _CO2 concentration detection device communication unit and _CO2 concentration detection device, 5b communication between ventilation device communication unit and ventilation device, 5c communication between external device communication unit and external device, 10 ventilation system, 11 control unit, 12 memory unit, 13 operation unit, 13a setting unit, 14 _CO2 concentration detection device communication unit, 15 ventilation device communication unit, 16 external device communication unit, 18 human presence sensor, 21 ventilation control device communication unit, 22 _CO2 concentration detection unit, 100 air conditioner, 101 indoor unit, 102 outdoor unit, 103 connecting piping, 104 connecting piping, 200 air conditioning system.

Claims (11)

a _CO2 concentration detection device that detects the _CO2 concentration in a room;
a ventilation device for ventilating the room;
a ventilation control device having a first control mode in which the ventilation device is put into an operating state when the _CO2 concentration is equal to or higher than a first concentration threshold value that is lower than a ventilation reference value that is a reference value requiring ventilation, and a second control mode in which the ventilation device is put into an operating state when it is estimated that the _CO2 concentration will exceed the ventilation reference value based on the _CO2 concentration and the rate of increase of the _CO2 concentration,
The second control mode is a mode in which the ventilation device is put into operation when the CO2 _{concentration} is equal to or higher than a second concentration threshold that is lower than the first concentration threshold, and the rate of change of the CO2 _{concentration} is equal to or higher than a predetermined concentration change rate threshold . Indoor CO ₂ CO concentration detection ₂ a concentration detection device;
a ventilation device for ventilating the room;
The CO ₂ a first control mode in which the ventilation device is put into an operating state when the CO concentration is equal to or greater than a first concentration threshold value that is lower than a ventilation reference value that is a reference value that requires ventilation; ₂ concentration and the CO ₂ Based on the rate of increase in the concentration, ₂ a second control mode that operates the ventilation device when the concentration is estimated to exceed the ventilation reference value;
The ventilation control device includes:
The CO ₂ concentration and the CO ₂ The operation of the first control mode or the second control mode is performed based on the rate of increase in concentration,
The CO ₂ Equipped with multiple concentration detection devices,
The ventilation control device includes:
A plurality of the CO ₂ Among the concentration detection devices, the CO ₂ Identifying the concentration detection device, ₂ A ventilation system that performs control in the first control mode and the second control mode based on the detection result of a concentration detection device. The second control mode is a mode in which the ventilation device is put into operation when the _CO2 concentration is equal to or higher than a second concentration threshold that is lower than the first concentration threshold, and the rate of change of the _CO2 concentration is equal to or higher than a predetermined concentration change rate threshold. The ventilation system according to claim 2 . The ventilation system according to claim 1 or 3 , wherein the ventilation control device stops the ventilation device when the _CO2 concentration is less than the second concentration threshold value. The ventilation control device changes the ventilation device from an operating state to a stopped state when the _CO2 concentration falls below the first concentration threshold while operating in the first control mode. The ventilation system according to any one of claims 1 to 3 . 4. The ventilation system according to claim 1 , wherein the ventilation control device includes an operation unit through which a user inputs the concentration change rate threshold, and the concentration change rate threshold is determined by the user inputting the concentration change rate threshold into the operation unit. A ventilation system as described in any one of claims 1 to 3, which is provided with an operation switch for switching on and off the ventilation device, and the operation switch can be operated to manually switch on and off the ventilation device. a setting unit that is operated by a user and sets the priority between a manual operation mode and an automatic operation mode;
The ventilation control device includes:
If the priority of the automatic operation mode is higher than the priority of the manual operation mode, control the ventilation device based on the _CO2 concentration and the rate of increase of the _CO2 concentration;
The ventilation system according to claim 7 , wherein when the priority of the manual operation mode is higher than the priority of the automatic operation mode, the ventilation device is controlled based on the operation of the operation switch. The ventilation control device includes:
acquiring the number of people in the room, and if the number of people is equal to or greater than a predetermined number-of-people threshold, performing a correction to decrease the first concentration threshold and the second concentration threshold;
The ventilation system according to claim 1 or 3 , wherein when the number of people falls below the number of people threshold, the first concentration threshold and the second concentration threshold are restored to their original values. The ventilation control device includes:
When a decrease in ventilation volume due to deterioration of the ventilation device is detected, the first concentration threshold and the second concentration threshold are decreased;
The ventilation system according to claim 1 or 3 , wherein the first concentration threshold and the second concentration threshold are restored to their original values when a decrease in ventilation volume due to deterioration of the ventilation device is resolved. An air conditioning system equipped with the ventilation system described in any one of claims 1 to 3.