JP7611679B2 - Ventilation control device and ventilation control method - Google Patents

Description

This invention relates to a ventilation control device and a ventilation control method.

An air conditioning control system performs air conditioning control for a controlled space (room) (see, for example, Patent Document 1). Conventionally, such air conditioning control systems may control the amount of outside air taken in for ventilation of the controlled space to be reduced as much as possible during periods when the load on the air conditioner is high (summer and winter) in order to conserve energy.

In this case, for example, the air conditioning control system may perform ventilation control ( _CO2 control) using the concentration of _CO2 . There are two types of _CO2 control: "control of the ratio of outside air and return air" and "variable control of the minimum air volume setting in a supply air VAV (Variable Air Volume) unit."

In the "control of the ratio of outside air and return air", as shown in FIG. 7A, for example, the air conditioning control system performs control to increase the ratio of outside air contained in the supply air according to the concentration of CO ₂ in the controlled space or return air measured by a CO ₂ sensor. That is, when the concentration of CO ₂ in the controlled space or return air is equal to or higher than a set value (e.g., 900 ppm), the air conditioning control system increases the ratio of outside air (increases the amount of outside air and decreases the amount of return air accordingly), and when the concentration of CO ₂ is less than the set value, the air conditioning control system controls so as not to take in as much outside air as possible. This control is performed by calculating the required amount of outside air within the range between the minimum amount of outside air (local exhaust amount) and the design amount of outside air. The local exhaust amount is the amount of exhaust air discharged to the outside by an exhaust fan (such as the exhaust fan 8 shown in FIG. 1, which will be described later) provided in the controlled space. The design amount of outside air is the amount of outside air taken in that satisfies the ventilation standard value determined by the design.
In FIG. 7A, reference numeral 701 indicates the amount of outside air supplied to the air conditioner, reference numeral 702 indicates the amount of return air supplied to the air conditioner out of the amount of air sent from the controlled space by the return air fan (return air fan air volume), and reference numeral 703 indicates the amount of exhaust air exhausted to the outside out of the return air fan air volume (general exhaust volume).

In "variable control of minimum air volume setting in supply air VAV unit," the air conditioning control system controls the supply air VAV unit to increase the minimum blow-out volume (minimum air volume) according to the _CO2 concentration in the controlled space measured by the _CO2 sensor, as shown in Fig. 7B (i.e., blows out if there is little supply of air to maintain room temperature). Note that Fig. 7B shows a case where the air conditioning control system performs cooling.
In Fig. 7B, reference numeral 704 indicates the range in which the minimum air volume in the supply VAV unit is increased or decreased according to the _CO2 concentration. The upper limit of the minimum air volume is a value determined by design. The lower limit of the minimum air volume can be set up to 0 if the air conditioning control system includes a control to maintain the minimum air volume of the air conditioner.

In addition, when an air conditioning control system only uses "control of the ratio of outside air and return air" as _CO2 control, it is common for a _CO2 sensor to be installed in the return air duct in the air conditioning control system, taking into account ease of maintenance.

For example, air conditioning control systems may also perform ventilation control (headcount control) using the number of people in the controlled space. In this headcount control, the air conditioning control system measures the number of people in the controlled space and controls the amount of outside air taken in according to that number.

In addition, as shown in FIG. 8, for example, the air conditioning control system may have a function to implement control to increase the proportion of outside air before opening the chilled water valve (outside air cooling control) when the cooling energy consumption can be reduced by taking in outside air. That is, in this case, the air conditioning control system sets the amount of outside air taken in to less than the designed outside air volume when outside air cooling is disabled, but makes it possible to make the amount of outside air taken in greater than or equal to the designed outside air volume when outside air cooling is enabled, thereby reducing the amount of cold energy consumed. Note that with outside air cooling control, there is no change in the amount of air supplied, and the amount of outside air taken in can be increased to the maximum outside air volume.

As shown in Fig. 9, the control range of the air supply volume (air supply volume supplied from the air conditioner) in the air conditioning control system is the range between the minimum air supply volume and the rated air supply volume, and the air conditioning control system adjusts the air supply volume according to the load condition of the controlled space, etc. The minimum air supply volume is the minimum value of the air supply volume that the air conditioner has as an equipment.
Furthermore, the control range of the amount of outdoor air taken in by the air conditioning control system (amount of outdoor air supplied to the air conditioner) is a range between the minimum outdoor air volume (local exhaust volume) and the designed outdoor air volume when outdoor air cooling is disabled, and the air conditioning control system adjusts the amount of outdoor air taken in by _CO2 control. Furthermore, the control range of the amount of outdoor air taken in by the air conditioning control system (amount of outdoor air supplied to the air conditioner) is a range between the required outdoor air volume and the maximum outdoor air volume when outdoor air cooling is enabled, and the air conditioning control system adjusts the amount of outdoor air taken in by outdoor air cooling control.
In FIG. 9, reference numeral 901 indicates the control range of the amount of supply air, reference numeral 902 indicates the control range of the amount of outdoor air taken in (when outdoor air cooling is disabled), and reference numeral 903 indicates the control range of the amount of outdoor air taken in (when outdoor air cooling is enabled).

JP 2018-173200 A

On the other hand, during an epidemic of an airborne infectious disease, it is necessary to prioritize reducing the risk of infection for people in the controlled space over energy conservation, and to increase the proportion of outside air in the supply air as much as possible. However, with conventional air conditioning control systems, the amount of outside air taken in does not exceed the designed amount of outside air except when controlling outdoor air cooling.
Thus, it cannot be said that conventional air conditioning control systems are able to flexibly control the proportion of outside air contained in the supply air.

This invention was made to solve the above problems, and aims to provide a ventilation control device that can flexibly control the proportion of outside air contained in the supply air in comparison to conventional methods.

The ventilation control device of the present invention is characterized in that it comprises a level setting unit that receives user input and sets a normal level that increases the proportion of outside air taken in when the CO2 concentration is 900 ppm or higher _and controls to take in as little outside air as possible when the CO2 concentration is less than 900 ppm _, and one or more levels for controlling to increase the proportion of outside air contained in the supply air relative to the normal level, and an outside air volume control unit that controls the proportion of outside air contained in the supply air generated by the air conditioner for the controlled space, based on the level set by the level setting unit.

With the above-mentioned configuration, this invention makes it possible to flexibly control the proportion of outside air contained in the supply air, compared to the conventional method.

1 is a diagram showing a configuration example of an air conditioning control system according to a first embodiment; FIG. 2 is a diagram illustrating a configuration example of a controller according to the first embodiment. 5 is a flowchart showing an example of a ventilation control operation by the controller according to the first embodiment. 4A and 4B are diagrams for explaining the effect of the ventilation control operation by the controller according to the first embodiment. 5A and 5B are diagrams for explaining a case where the amount of outside air taken in is simply increased in the air-conditioning control system according to embodiment 1. FIG. 6A and 6B are diagrams for explaining the effect of the ventilation control operation by the controller according to the first embodiment. 7A and 7B are diagrams explaining _CO2 control by a conventional air conditioning control system, where FIG. 7A explains "control of the ratio of outside air and return air" and FIG. 7B explains "variable control of the minimum air volume setting in the supply VAV unit." FIG. 1 is a diagram illustrating outdoor air cooling control by a conventional air conditioning control system. FIG. 1 is a diagram showing an example of a control range of the amount of supply air and the amount of intake of outside air by a conventional air conditioning control system.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
Embodiment 1.
Fig. 1 is a diagram showing an example of the configuration of an air conditioning control system according to embodiment 1. Note that arrows shown in Fig. 1 indicate the flow of air.
An air conditioning control system performs air conditioning control for a controlled space (room). Fig. 1 shows a specific floor in a building, and illustrates a case in which the air conditioning control system performs air conditioning control for a plurality of rooms provided on that floor. Fig. 1 shows two private rooms 101a, 101b and one large room 102 as controlled spaces. A corridor 103 is connected to the large room 102, and the corridor 103 is further connected to a small room 104 such as a toilet.

The air conditioning control system shown in Fig. 1 includes an outside air VAV unit 1, a cold water valve (valve) 2a, a hot water valve (valve) 2b, a humidifier valve 3, an air conditioner 4, a temperature sensor 5, a temperature sensor 6, a supply air VAV unit 7, an exhaust fan 8, a return air fan 9, a return air damper 10, an exhaust VAV unit 11, a temperature and humidity sensor 12, a _CO2 sensor 13, a _CO2 sensor 14, a human detection sensor 15, and a controller 16. In Fig. 1, connection lines between the controller 16 and each part of the air conditioning control system are not shown.

The controller 16 is realized by a processing circuit such as a system LSI (Large Scale Integration) or a CPU (Central Processing Unit) that executes a program stored in a memory or the like.

The outdoor air VAV unit 1 is provided in the outdoor air duct 17, takes in outdoor air from the outdoor air port 18, and supplies the outdoor air to the air conditioner 4. The amount of outdoor air taken in by the outdoor air VAV unit 1 (the amount of outdoor air supplied to the air conditioner 4) is controlled by the controller 16.

The cold water valve 2a is provided in a cold water supply passage 19a through which cold water flows, and opens and closes the cold water supply passage 19a by adjusting the opening degree. The cold water valve 2a adjusts the flow rate of cold water in the cold water supply passage 19a, and adjusts the amount of cold water supplied to a cold water coil 401a (described later) of the air conditioner 4. The opening degree of the cold water valve 2a is controlled by the controller 16.
The cold water valve 2a may also have a function of measuring the flow rate of cold water in the cold water supply passage 19a.

The hot water valve 2b is provided in a hot water supply passage 19b through which hot water flows, and opens and closes the hot water supply passage 19b by adjusting the opening degree. The hot water valve 2b adjusts the flow rate of hot water in the hot water supply passage 19b, and adjusts the amount of hot water supplied to a hot water coil 401b (described later) of the air conditioner 4. The opening degree of the hot water valve 2b is controlled by the controller 16.
The hot water valve 2b may also have a function of measuring the flow rate of hot water in the hot water supply passage 19b.

The humidification valve 3 is provided in the supply path 20 through which water or steam flows, and opens and closes the supply path 20 by adjusting the opening degree. This humidification valve 3 adjusts the flow rate of water or steam in the supply path 20, and adjusts the amount of water or steam supplied to a humidifier 402 (described later) included in the air conditioner 4. The opening degree of this humidification valve 3 is controlled by the controller 16.

The air conditioner 4 generates conditioned air for the controlled space using outside air from the outside air VAV unit 1 and return air from the return air damper 10, and supplies the conditioned air as supply air to the supply air VAV unit 7 via the supply air duct 21. The air conditioner 4 shown in FIG. 1 has a cold water coil (coil) 401a, a hot water coil (coil) 401b, a humidifier 402, and a supply air fan 403.

The cold water coil 401a is connected to a cold water supply passage 19a, and cold water is supplied from the cold water supply passage 19a.
The hot water coil 401b is connected to a hot water supply passage 19b, and hot water is supplied from the hot water supply passage 19b.
The humidifier 402 is connected to the supply path 20 and receives water or steam from the supply path 20 .
In the air conditioner 4, heat exchange is performed with the outside air from the outside air VAV unit 1 and the return air from the return air damper 10 using a cold water coil 401a or a hot water coil 401b, and the humidity is adjusted using a humidifier 402, thereby generating conditioned air.
The supply air fan 403 supplies the conditioned air as supply air to the supply air VAV unit 7 via the supply air duct 21. The rotation speed of the supply air fan 403 is controlled by the controller 16.

Note that FIG. 1 shows a case where the coils of the air conditioner 4 are a cold water coil 401a and a hot water coil 401b. However, this is not limited to the above, and the air conditioner 4 may have a cold or hot water coil as a coil. In this case, the air conditioning control system is provided with a cold or hot water supply path as a supply path through which cold water or hot water flows, and a cold or hot water valve that opens and closes the cold or hot water supply path is provided as a valve. Note that the cold or hot water valve may have a function of measuring the flow rate in the cold or hot water supply path.

The temperature sensor 5 is provided in the supply air duct 21 and measures the temperature of the supply air from the air conditioner 4. The temperature measured by the temperature sensor 5 is notified to the controller 16.

The temperature sensor 6 is provided in the controlled space and measures the temperature of the controlled space. The temperature measured by this temperature sensor 6 is notified to the supply air VAV unit 7. In FIG. 1, one temperature sensor 6 is provided in the private room 101a, one is provided in the private room 101b, and two are provided in the large room 102.

The supply air VAV unit 7 is installed in the controlled space and supplies the supply air from the air conditioner 4 to the controlled space through the supply air port 22. Based on the temperature measured by the temperature sensor 6 installed in the controlled space to which it supplies supply air, the supply air VAV unit 7 adjusts the amount of supply air (air volume) it blows out so that the temperature matches the set temperature. The amount of supply air blown out by the supply air VAV unit 7, together with the set temperature and the temperature measured by the temperature sensor 6, is notified to the controller 16 as the load status of the controlled space. In FIG. 1, one supply air VAV unit 7 is installed in the private room 101a, one in the private room 101b, and two in the large room 102.

The exhaust fan 8 is provided in the controlled space, and exhausts the air in the controlled space to the outside through the exhaust port 23. In FIG.
In FIG. 1, the large room 102 and the corridor 103 are connected via an air vent 24 .

The return air fan 9 is provided in the return air duct 25 and supplies the air in the controlled space as return air to the return air damper 10 via a return air port 26 provided in the controlled space.

The return air damper 10 is provided in the return air duct 25, and opens and closes the return air duct 25 by adjusting the opening degree. This return air damper 10 adjusts the flow rate of the return air in the return air duct 25, and adjusts the amount of return air supplied to the air conditioner 4 (return air volume). The opening degree of this return air damper 10 is controlled by the controller 16.

The exhaust VAV unit 11 is provided in the return air duct 25 and exhausts at least a portion of the return air from the return air fan 9 to the outside via the exhaust port 27 as exhaust. Note that the exhaust volume (general exhaust volume) by the exhaust VAV unit 11 may become zero. The exhaust volume by the exhaust VAV unit 11 is controlled by the controller 16.

The temperature and humidity sensor 12 is installed in the return air duct 25 and measures the temperature and humidity of the return air. The temperature and humidity measured by the temperature and humidity sensor 12 are notified to the controller 16.

The CO2 sensor 13 is provided in the space to be controlled and measures the concentration of _CO2 in the space to be controlled. The concentration of _CO2 measured by the _CO2 sensor ₁₃ is notified to the controller 16. In Fig. 1, one _CO2 sensor 13 is provided in the private room 101a.

The CO ₂ sensor 14 is provided in the return air duct 25 and measures the concentration of CO ₂ in the return air duct 25. The concentration of CO ₂ measured by this CO ₂ sensor 14 is notified to the controller 16.

The human detection sensor 15 is provided in the controlled space and measures the number of people present in the controlled space. The number of people measured by the human detection sensor 15 is notified to the controller 16. In FIG. 1, one human detection sensor 15 is provided in the private room 101b.

The controller 16 performs air conditioning control based on the information notified from each part.
For example, the controller 16 controls the supply air by controlling the cold water valve 2a, the hot water valve 2b, the humidification valve 3, and the air conditioner 4. Specifically, the controller 16 controls the opening degree of the cold water valve 2a or the opening degree of the hot water valve 2b and the opening degree of the humidification valve 3 so that the temperature and humidity of the controlled space become the set temperature and the set humidity based on the temperature measured by the temperature sensor 5. That is, the controller 16 adjusts the temperature of the supply air from the air conditioner 4 by controlling the amount of cold water supplied to the cold water coil 401a or the amount of hot water supplied to the hot water coil 401b, and adjusts the humidity of the supply air from the air conditioner 4 by controlling the amount of water or steam supplied to the humidifier 402. The controller 16 also adjusts the supply amount (supply air amount) of the supply air from the air conditioner 4 by controlling the rotation speed of the supply air fan 403 so as to satisfy the blowing amount required by the supply air VAV unit 7. At this time, the controller 16 may change the set temperature, etc., depending on the load condition of the controlled space notified by the supply air VAV unit 7.

In addition, the controller 16 (ventilation control device) controls the outdoor air VAV unit 1, the return air damper 10 and the exhaust VAV unit 11, thereby controlling ventilation (the amount of outdoor air taken in).
The controller 16 shown in FIG. 1 performs ventilation control using the concentration of CO ₂ (CO ₂ control) and ventilation control using the number of people in the controlled space (number of people control).

In the _CO2 control, the controller 16 controls the amount of outside air taken in based on the _CO2 concentration measured by the _CO2 sensor 13 or the _CO2 concentration measured by the _CO2 sensor 14. The controller 16 shown in Fig. 1 performs "control of the ratio of outside air and return air" and "variable control of the setting of the minimum air volume in the supply air VAV unit 7" as _CO2 control.

That is, in “controlling the ratio of outside air and return air”, the controller 16 controls the amount of outside air taken in based on the CO ₂ concentration measured by the CO ₂ sensor 13 or the CO ₂ concentration measured by the CO ₂ sensor 14 .
At this time, when the operation mode of the controller 16 is an energy saving priority mode described later, the controller 16 increases the ratio of the amount of outside air taken in (increases the amount of outside air and reduces the amount of return air accordingly) when the concentration of _CO2 is equal to or higher than a set value (e.g., 900 ppm), as in the conventional case, and controls so as to take in as little outside air as possible when the concentration of _CO2 is below the set value. On the other hand, when the operation mode of the controller 16 is a ventilation mode described later, the controller 16 controls so as to increase the ratio of outside air, while controlling so as to stop increasing the amount of outside air taken in or reduce the amount of outside air taken in when the processing capacity of the air conditioner 4 becomes equal to or higher than a threshold value.

Furthermore, in the "variable control of the minimum air volume setting in the supply air VAV unit 7", as in the conventional case, the controller 16 controls the supply air VAV unit 7 to increase the minimum blow-out volume (minimum air volume) based on the _CO2 concentration measured by the _CO2 sensor 13 (i.e., blows out air if there is little supply of air to maintain room temperature).

In addition, in the case of headcount control, the controller 16 controls the amount of outside air taken in based on the number of people measured by the human detection sensor 15.
At this time, when the operation mode of the controller 16 is the energy saving priority mode, the controller 16 performs the same control as in the conventional case. On the other hand, when the operation mode of the controller 16 is the ventilation mode, the controller 16 performs control to increase the proportion of outside air, and when the processing capacity of the air conditioner 4 becomes equal to or greater than a threshold value, the controller 16 performs control to stop increasing the amount of outside air taken in or to reduce the amount of outside air taken in.

In the following, the system (controlled space) in which the controller 16 controls the ventilation volume (amount of outside air taken in) based on the _CO2 concentration will be referred to as the _CO2 control system, and the system (controlled space) in which the controller 16 controls the ventilation volume (amount of outside air taken in) based on the number of people in the controlled space will be referred to as the number of people control system.

The controller 16 may also have a function of controlling outdoor air cooling. In this case, when the controller 16 determines that outdoor air cooling is effective for the controlled space, it controls the amount of outdoor air supplied to the air conditioner 4 before controlling the supply air temperature with the chilled water valve 2a.

As shown in FIG. 2, the controller 16 has a function of controlling ventilation in the air conditioning control system, which includes an operation mode setting unit 1601, a ventilation level setting unit 1602, an outdoor air volume calculation unit 1603, a ventilation deficiency determination unit 1604, a setting confirmation unit 1605, a ventilation state determination unit 1606, a valve state determination unit 1607, and an outdoor air volume control unit 1608.

The operation mode setting unit 1601 sets the operation mode of the controller 16. Examples of the operation modes of the controller 16 include an energy saving priority mode, a ventilation mode, and a maximum ventilation mode.
The energy saving priority mode is a mode in which the same control as the conventional control is performed, in which energy saving is prioritized and control is performed to reduce the intake of outside air as much as possible.
The ventilation mode is a mode that prioritizes ventilation and performs control to maximize the intake of outside air while maintaining the environment of the controlled space.
The maximum ventilation mode is a mode that controls the intake of maximum outside air, but this mode may cause a deterioration in the temperature of the controlled space.

In this operation mode setting unit 1601, for example, a screen for setting the operation mode is displayed on a display device (not shown) used by a user (such as a building manager or a person in the controlled space). Then, the operation mode setting unit 1601 sets the operation mode to the operation mode selected by the user using the screen.

The ventilation level setting unit 1602 sets a level (ventilation level) when the operation mode of the controller 16 is the ventilation mode. The ventilation level includes, for example, the allowable concentration of _CO2 or the allowable outdoor air volume per person. The ventilation level setting unit 1602 can set the ventilation level from a plurality of levels. For example, the ventilation level setting unit 1602 can set the ventilation level from among a level (level 1) in which the allowable concentration of _CO2 is 900 ppm and the allowable outdoor air volume per person is 30 ^m3 /h, a level (level 2) in which the allowable concentration of _CO2 is 700 ppm and the allowable outdoor air volume per person is 40 ^m3 /h, and a level (level 3) in which the allowable concentration of _CO2 is 500 ppm and the allowable outdoor air volume per person is 50 ^m3 /h. In this example, the controller 16 performs control so as to increase the proportion of outdoor air contained in the supply air as the level number increases.

In this ventilation level setting unit 1602, for example, a screen for setting the ventilation level is displayed on a display device used by the user. Then, the ventilation level setting unit 1602 sets the ventilation level to the ventilation level selected by the user using the screen.

The operation mode setting unit 1601 and the ventilation level setting unit 1602 constitute a "level setting unit that sets a level based on at least one of the indicators of the environment of the controlled space and energy consumption." Examples of the environment of the controlled space include air quality and thermal environment. In the above example, the energy saving priority mode corresponds to level 0 (control that reduces the proportion of outside air contained in the supply air compared to the ventilation mode (levels 1 to 3)), and the maximum ventilation mode corresponds to level 4 (control that increases the proportion of outside air contained in the supply air compared to the ventilation mode (levels 1 to 3)).

Outside air amount calculation section 1603 calculates, for each supply air VAV unit 7, the amount of outside air contained in the supply air blown out by supply air VAV unit 7.
In this case, first, the outdoor air volume calculation unit 1603 calculates the volume of supply air from the air conditioner 4 based on the volume of supply air blown out from each supply air VAV unit 7. Then, the outdoor air volume calculation unit 1603 calculates the outdoor air introduction ratio based on the volume of outdoor air taken in and the volume of supply air. The outdoor air introduction ratio is the ratio of the volume of outdoor air taken in to the volume of supply air. Then, the outdoor air volume calculation unit 1603 calculates, for each supply air VAV unit 7, the volume of outdoor air contained in the supply air blown out by the supply air VAV unit 7 based on the outdoor air introduction ratio and the volume of supply air blown out from each supply air VAV unit 7.

The ventilation insufficiency determination unit 1604 determines whether or not there is an insufficient ventilation state for each system.
At this time, the ventilation insufficiency determination unit 1604 determines that the _CO2 control system is in a state of insufficient ventilation if the _CO2 concentration is equal to or higher than a threshold value (e.g., 1000 ppm), and determines that the ventilation insufficiency state is not present otherwise.
Furthermore, for the number of people control system, the ventilation insufficiency determination unit 1604 determines that there is insufficient ventilation if the value obtained by multiplying the number of people in the controlled space by a threshold value (e.g., 30 ^m3 /h) is equal to or greater than the amount of outside air contained in the supply air blown out by the supply air VAV unit 7 installed in the controlled space, and determines that there is no insufficient ventilation in other cases. Note that the ventilation insufficiency determination unit 1604 uses the calculation result by the outside air amount calculation unit 1603 for the amount of outside air contained in the supply air blown out by the supply air VAV unit 7.

The result of the determination by the ventilation insufficiency determination unit 1604 is displayed on the display device used by the user. The user may then change the setting of the operation mode in the operation mode setting unit 1601 and the setting of the ventilation level in the ventilation level setting unit 1602 based on the result of the determination displayed on the display device. That is, in this case, the operation mode setting unit 1601 sets the operation mode to the operation mode selected by the user based on the result of the determination by the ventilation insufficiency determination unit 1604. Also, the ventilation level setting unit 1602 sets the ventilation level to the ventilation level selected by the user based on the result of the determination by the ventilation insufficiency determination unit 1604.

The setting confirmation unit 1605 confirms the operation mode set by the operation mode setting unit 1601.

When the setting confirmation unit 1605 confirms that the operating mode is the ventilation mode, the ventilation state determination unit 1606 determines whether the ventilation state for each system satisfies the ventilation level set by the ventilation level setting unit 1602.

At this time, for example, for the _CO2 control system, the ventilation state determination unit 1606 compares the _CO2 concentration with the allowable concentration indicated by the ventilation level and determines whether the ventilation state is "insufficient,""appropriate," or "excessive" with respect to the ventilation level. That is, when the _CO2 concentration is equal to or greater than the allowable concentration, the ventilation state determination unit 1606 determines that the ventilation state is insufficient with respect to the ventilation level, when the _CO2 concentration is equal to or greater than the lower limit and less than the allowable concentration, the ventilation state is appropriate with respect to the ventilation level, and when the _CO2 concentration is less than the lower limit, the ventilation state is excessive with respect to the ventilation level. The lower limit is a value smaller than the allowable concentration, and the value changes depending on the allowable concentration (for example, the lower limit = allowable concentration - 50).

Also, for example, for the number of people control system, the ventilation state determination unit 1606 compares the value (indoor required outdoor air volume) obtained by multiplying the number of people in the controlled space by the allowable outdoor air volume indicated by the ventilation level with the outdoor air volume (indoor supply outdoor air volume) contained in the supply air blown out by the supply air VAV unit 7 provided in the controlled space, and determines whether the ventilation state is "insufficient,""appropriate," or "excessive" for the ventilation level. That is, the ventilation state determination unit 1606 determines that the ventilation state is insufficient for the ventilation level when the indoor required outdoor air volume is equal to or greater than the indoor supply outdoor air volume, determines that the ventilation state is appropriate for the ventilation level when the indoor required outdoor air volume is equal to or greater than the lower limit value and less than the indoor supply outdoor air volume, and determines that the ventilation state is excessive for the ventilation level when the indoor required outdoor air volume is less than the lower limit value. The lower limit value is a value smaller than the indoor supply outdoor air volume, similar to the lower limit value in the case of the _CO2 control system, and the value changes depending on the indoor supply outdoor air volume. It should be noted that the ventilation state determination unit 1606 uses the calculation result by the outside air volume calculation unit 1603 for the amount of outside air contained in the supply air blown out by the supply air VAV unit 7.

The valve state determination unit 1607 determines the capacity state of the valve when the ventilation state determination unit 1606 determines that the ventilation state in at least any one of the systems is insufficient for the ventilation level.
At this time, if the valve opening is equal to or greater than a threshold value (e.g., 90% (initial value)), the valve state determination unit 1607 determines that the controllable characteristics of heat exchange by the valve are in an insufficient capacity state, and otherwise determines that the controllable characteristics of heat exchange by the valve are not in an insufficient capacity state.
Furthermore, if the valve has a function of measuring the flow rate in the supply path, the valve state determination unit 1607 may determine the capacity state of the valve based on the flow rate. In this case, the valve state determination unit 1607 determines that the controllable characteristic of heat exchange by the valve is in an insufficient capacity state when the flow rate in the supply path is equal to or greater than a threshold value (e.g., near the rated flow rate), and otherwise determines that the controllable characteristic of heat exchange by the valve is not in an insufficient capacity state.

The outdoor air volume control unit 1608 controls the amount of outdoor air taken in (ventilation volume) by controlling the outdoor air VAV unit 1, the exhaust VAV unit 11, and the return air damper 10 based on the operation mode set by the operation mode setting unit 1601 and the ventilation level set by the ventilation level setting unit 1602.

At this time, if the setting confirmation unit 1605 confirms that the operating mode is energy saving priority mode, the outdoor air volume control unit 1608 performs normal control (control to reduce the intake of outdoor air as much as possible without causing insufficient ventilation).
Furthermore, when the setting confirmation unit 1605 confirms that the operation mode is the maximum ventilation mode, the outside air amount control unit 1608 performs control to take in the maximum amount of outside air.

Furthermore, when the setting confirmation unit 1605 confirms that the operation mode is the ventilation mode, the outside air volume control unit 1608 performs control to increase the amount of outside air taken in as much as possible while maintaining the environment of the controlled space.
That is, when the valve state determination unit 1607 determines that the controllable characteristic of the heat exchange by the valve is not in a capacity insufficient state, the outdoor air amount control unit 1608 controls to increase the amount of outdoor air taken in. Also, when the valve state determination unit 1607 determines that the controllable characteristic of the heat exchange by the valve is in a capacity insufficient state, the outdoor air amount control unit 1608 controls to stop the increase in the amount of outdoor air taken in or to reduce the amount of outdoor air taken in. Also, when the ventilation state determination unit 1606 determines that the ventilation state in all systems is excessive for the ventilation level, the outdoor air amount control unit 1608 controls to reduce the amount of outdoor air taken in. Also, when the ventilation state determination unit 1606 determines that the ventilation state in none of the systems is insufficient for the ventilation level and that the ventilation state in any of the systems is not excessive for the ventilation level, the outdoor air amount control unit 1608 controls to maintain the amount of outdoor air taken in without changing it.

2 shows a case where the ventilation insufficiency determination unit 1604 is provided in the controller 16. However, the ventilation insufficiency determination unit 1604 is not an essential component, and may not be provided in the controller 16.
2 shows a case where the outside air volume calculation unit 1603 is provided in the controller 16. However, if the controller 16 does not control the number of people, the outside air volume calculation unit 1603 is not necessary.

Next, an example of a ventilation control operation by the controller 16 according to the first embodiment shown in FIG. 2 will be described with reference to FIG.
The operation mode setting unit 1601 sets the operation mode of the controller 16. The ventilation level setting unit 1602 sets the ventilation level when the operation mode of the controller 16 is the ventilation mode. In this way, the controller 16 can select the "ventilation mode" as a countermeasure to prevent infectious diseases, and can set the "ventilation level" to balance the amount of outside air taken in and the amount of energy consumed.

In an example of ventilation control operation by the controller 16 of embodiment 1 shown in Figure 2, as shown in Figure 3, first, the outdoor air volume calculation unit 1603 calculates the volume of outdoor air contained in the supply air blown out by the supply air VAV unit 7 for each supply air VAV unit 7 (step ST301).
In this case, first, as shown in the following formula (1), the outside air amount calculation unit 1603 calculates the supply air amount based on the supply air blow-out amount of each supply air VAV unit 7. Then, as shown in the following formula (2), the outside air amount calculation unit 1603 calculates the outside air introduction ratio based on the outside air intake amount and supply air amount. Then, as shown in the following formula (3), the outside air amount calculation unit 1603 calculates the amount of outside air contained in the supply air blown out by the supply air VAV unit 7 for each supply air VAV unit 7 based on the outside air introduction ratio and the supply air blow-out amount of each supply air VAV unit 7.
Supply air volume=Σ(air supply volume of each supply VAV unit 7) (1)
Outdoor air intake ratio = outdoor air intake amount ÷ supply air amount (2)
Amount of outside air contained in the supply air blown out by each supply air VAV unit 7 = Amount of supply air blown out by each supply air VAV unit 7 × Outside air introduction ratio (3)

Next, the ventilation insufficiency determining unit 1604 determines whether or not each system is in an insufficient ventilation state (step ST302).
At this time, the ventilation insufficiency determination unit 1604 determines that the _CO2 control system is in a state of insufficient ventilation if the _CO2 concentration is equal to or higher than a threshold value (e.g., 1000 ppm), and determines that the ventilation insufficiency state is not present otherwise.
In addition, for the number of people control system, the ventilation insufficiency determination unit 1604 determines that there is an insufficient ventilation state if the number of people in the controlled space multiplied by a threshold value (e.g., 30 ^m3 /h) is equal to or greater than the amount of outside air contained in the supply air blown out by the supply air VAV unit 7 installed in the controlled space, and determines that there is no insufficient ventilation state in any other cases.

The result of the determination by the ventilation insufficiency determination unit 1604 is displayed on the display device used by the user. The user may then change the setting of the operation mode in the operation mode setting unit 1601 and the setting of the ventilation level in the ventilation level setting unit 1602 based on the result of the determination displayed on the display device. That is, in this case, the operation mode setting unit 1601 sets the operation mode to the operation mode selected by the user based on the result of the determination by the ventilation insufficiency determination unit 1604. Also, the ventilation level setting unit 1602 sets the ventilation level to the ventilation level selected by the user based on the result of the determination by the ventilation insufficiency determination unit 1604.

Next, the setting confirmation unit 1605 confirms whether the operation mode set by the operation mode setting unit 1601 is the ventilation mode (step ST303).

In this step ST303, if the setting confirmation unit 1605 confirms that the operation mode is the ventilation mode, the ventilation state determination unit 1606 determines whether the ventilation state in any system is insufficient for the ventilation level (step ST304).
At this time, the ventilation status determination unit 1606 determines that, for the _CO2 control system, if the _CO2 concentration is equal to or higher than the allowable concentration, the ventilation status is insufficient relative to the ventilation level, and otherwise determines that the ventilation status is not insufficient relative to the ventilation level.
In addition, for the number of people control system, the ventilation status determination unit 1606 determines that the ventilation status is insufficient for the ventilation level if the amount of outdoor air required indoors is equal to or greater than the amount of outdoor air supplied indoors, and otherwise determines that the ventilation status is not insufficient for the ventilation level.

In this step ST304, if the ventilation state determination unit 1606 determines that the ventilation state in at least one of the systems is insufficient relative to the ventilation level, the valve state determination unit 1607 determines whether the controllable characteristics of heat exchange by the valve are in a capacity insufficient state (step ST305).
At this time, if the valve opening is equal to or greater than a threshold value (e.g., 90% (initial value)) or if the flow rate in the supply path is equal to or greater than a threshold value (e.g., near the rated flow rate), the valve state determination unit 1607 determines that the controllable characteristics of heat exchange by the valve are in an insufficient capacity state, and otherwise determines that the controllable characteristics of heat exchange by the valve are not in an insufficient capacity state.

If the valve state determination unit 1607 determines in step ST305 that the controllable characteristics of the heat exchange by the valve are not in a capacity insufficient state, the outside air volume control unit 1608 controls the amount of outside air taken in to be increased (step ST306).

On the other hand, if the valve state determination unit 1607 determines in step ST305 that the controllable characteristic of the heat exchange by the valve is in a capacity insufficient state, the outdoor air volume control unit 1608 stops the increase in the amount of outdoor air taken in or reduces the amount of outdoor air taken in (step ST307). At this time, for example, when the valve opening degree is in a first range (e.g., 90% or more and less than 95%), the outdoor air volume control unit 1608 stops the increase in the amount of outdoor air taken in, and when the valve opening degree is in a second range (e.g., 95% or more) that is larger than the first range, reduces the amount of outdoor air taken in. The above is also the case when the capacity state of the valve is determined by the flow rate in the supply path.

On the other hand, if in step ST304 the ventilation status determination unit 1606 determines that the ventilation status in none of the systems is insufficient relative to the ventilation level, it determines whether the ventilation status in all of the systems is excessive relative to the ventilation level (step ST308).
At this time, the ventilation status determination unit 1606 determines that, for the _CO2 control system, the ventilation status is excessive for the ventilation level if the _CO2 concentration is below the lower limit value, and otherwise determines that the ventilation status is not excessive for the ventilation level.
In addition, for the number of people control system, the ventilation state determination unit 1606 determines that the ventilation state is excessive for the ventilation level if the amount of outdoor air required indoors is less than a lower limit value, and otherwise determines that the ventilation state is not excessive for the ventilation level.

If the ventilation state determination unit 1606 determines in step ST308 that the ventilation state in all systems is excessive relative to the ventilation level, the outdoor air volume control unit 1608 controls the amount of outdoor air taken in to be reduced (step ST309).

On the other hand, if the ventilation state determination unit 1606 determines in step ST308 that the ventilation state in any system is not excessive relative to the ventilation level, the outdoor air volume control unit 1608 controls the amount of outdoor air taken in to be maintained unchanged (step ST310).

On the other hand, in step ST303, if the setting confirmation unit 1605 confirms that the operation mode is not the ventilation mode, it checks whether the operation mode is the energy saving priority mode (step ST311).

If the setting confirmation unit 1605 confirms in step ST311 that the operating mode is the energy saving priority mode, the outdoor air volume control unit 1608 performs normal control (control to reduce the intake of outdoor air as much as possible without causing insufficient ventilation) (step ST312).

On the other hand, if the setting confirmation unit 1605 confirms in step ST311 that the operating mode is not the energy saving priority mode (i.e., the maximum ventilation mode), the outdoor air volume control unit 1608 performs control to take in as much outdoor air as possible (step ST313).

As described above, according to this embodiment 1, the controller 16 (ventilation control device) includes a level setting unit (operation mode setting unit 1601 and ventilation level setting unit 1602) that sets a level based on at least one of the indicators of the environment of the controlled space and energy consumption, and an outside air volume control unit 1608 that controls the proportion of outside air contained in the air supplied to the controlled space generated by the air conditioner 4 based on the level set by the level setting unit. This makes it possible for the controller 16 (ventilation control device) according to embodiment 1 to flexibly control the proportion of outside air contained in the supply air compared to conventional methods. Furthermore, this controller 16 makes it possible to balance the environment of the controlled space with consuming a large amount of energy.

Furthermore, in the controller 16 according to embodiment 1, when the amount of outside air is increased for ventilation, priority is given to increasing the proportion of outside air contained in the supply air, so the conveying power does not increase as in the _CO2 control of the conventional supply air VAV unit 7 (it is possible to take in a large amount of outside air without increasing the amount of supply air).

For example, as shown in Figure 4, consider a case where four or more people are present in a controlled space with a capacity of four people. Figure 4B shows a case where six people are present in a controlled space with a capacity of four people. In this case, the controller 16 according to embodiment 1 prioritizes increasing the proportion of outside air when in ventilation mode, making it possible to take in a large amount of outside air without increasing the amount of air supplied. As a result, appropriate outside air can be supplied even when more than the capacity of the controlled space is present.

Furthermore, in the controller 16 (ventilation control device) shown in FIG. 2, the outdoor air volume control unit 1608 increases the amount of outdoor air taken in when the valve state determination unit 1607 determines that the controllable characteristic of the heat exchange by the valve is not in a capacity insufficient state, and stops the increase in the amount of outdoor air taken in or reduces the amount of outdoor air taken in when the valve state determination unit 1607 determines that the controllable characteristic of the heat exchange by the valve is in a capacity insufficient state. As a result, this controller 16 (ventilation control device) can take in more outdoor air while maintaining the environment in the controlled space compared to the conventional method. That is, this controller 16 constantly monitors the processing capacity of the air conditioner 4 (valve opening or flow rate in the supply path), and when the processing capacity of the air conditioner 4 becomes equal to or greater than a threshold value, stops the increase in the amount of outdoor air taken in or reduces the amount of outdoor air taken in, thereby making it possible to take in the maximum amount of outdoor air while maintaining the environment in the controlled space. The effects of this configuration are shown below.

For example, as shown in FIG. 5, consider a case where the design value of the outdoor air ratio in an air conditioning control system is 1/5, and the outdoor air ratio is simply increased to 4/5 to perform cooling. In FIG. 5A (when the outdoor air ratio is 1/5), the outdoor air temperature is 36°C, the return air temperature is 26°C, the temperature inside the air conditioner 4 is 28°C, and the supply air temperature is 15°C. In this case, when high-temperature outdoor air is taken in, the temperature inside the air conditioner 4 rises. If the temperature inside the air conditioner 4 rises above the design value, the air conditioner 4 will not be able to cool the room, and the supply air temperature will rise. In FIG. 5B (when the outdoor air ratio is 4/5), the temperature inside the air conditioner 4 rises to 34°C, and the opening of the cold water valve 2a becomes 100%, so the air conditioner will not be able to cool the room, and the supply air temperature rises to 17°C. In other words, this state is a typical example of a state in which the control of heat exchange by the valve deviates from the controllable characteristics. In theory, normal control operations that use a lot of return air, which is already controlled to the target room temperature, will not deviate from the controllable range. However, if you switch to a state where a lot of outside air is used for ventilation purposes, it is important to note that there is a possibility of deviation from the controllable range.

As such, if an air conditioning control system were to simply try to bring in a lot of outside air as a measure to prevent infectious diseases, the capacity of the air conditioner 4 would be insufficient, and the indoor environment could deteriorate.

In contrast, as shown in FIG. 6, for example, in an air conditioning control system, when the design value of the outdoor air ratio is 1/5, consider a case where cooling is performed by increasing the outdoor air ratio while monitoring the processing capacity of the cold water valve 2a. In FIG. 6A (when the outdoor air ratio is 1/5), the outdoor air temperature is 36°C, the return air temperature is 26°C, the temperature inside the air conditioner 4 is 28°C, and the supply air temperature is 15°C. In this case, when high-temperature outdoor air is taken in, the temperature inside the air conditioner 4 rises. However, in the controller 16 shown in FIG. 2, the amount of outdoor air taken in is increased while monitoring the processing capacity of the air conditioner 4, and when the processing capacity of the air conditioner 4 becomes equal to or greater than a threshold value, the increase in the amount of outdoor air taken in is stopped or the amount of outdoor air taken in is reduced. In FIG. 6B, the increase in the amount of outdoor air taken in is stopped when the opening degree of the cold water valve 2a reaches 90% (the increase in the outdoor air ratio is stopped at 1/2). In this case, the cooling capacity of the air conditioner 4 remains unchanged, so the supply air temperature can be maintained at 15°C without increasing.

In the above, the ventilation level includes the allowable _CO2 concentration and the allowable amount of outdoor air per person. However, the ventilation level may include the allowable temperature of the controlled space. In this case, the ventilation level may include, for example, a level (level 5) where the allowable temperature is room temperature + 0.5°C or a level (level 6) where the allowable temperature is room temperature + 1.0°C.
In this case, the outside air amount control unit 1608 increases the amount of outside air taken in when the valve state determination unit 1607 determines that the controllable characteristic of heat exchange by the valve is not in a capacity insufficient state or when the temperature measured by the temperature sensor 6 is determined to be below the allowable temperature. That is, even when the valve state determination unit 1607 determines that the controllable characteristic of heat exchange by the valve is in a capacity insufficient state, the outside air amount control unit 1608 increases the amount of outside air taken in when the temperature measured by the temperature sensor 6 is below the allowable temperature. On the other hand, when the valve state determination unit 1607 determines that the controllable characteristic of heat exchange by the valve is in a capacity insufficient state and the temperature measured by the temperature sensor 6 is equal to or higher than the allowable temperature, the outside air amount control unit 1608 stops increasing the amount of outside air taken in or reduces the amount of outside air taken in.

Furthermore, in winter, increasing the amount of outside air taken in may result in a decrease in humidity in the controlled space. Therefore, the ventilation level may include the allowable humidity of the controlled space. Examples of allowable humidity include 40%, 45%, or 50%. The ventilation status determination unit 1606 then compares the humidity measured by the humidity sensor 12 with the allowable humidity to determine whether the ventilation status for each system satisfies the ventilation level set by the ventilation level setting unit 1602.

In the above, the level setting unit (operation mode setting unit 1601 and ventilation level setting unit 1602) has been described as accepting manual input from the user to set the levels (operation mode and ventilation level). However, this is not limiting, and the level setting unit may set the level automatically. In this case, the level setting unit sets the level based on at least one of the power consumption status (the difference between the contracted power and the current power consumption), the demand response, or the outside air conditions, for example.

In addition, any of the components of the embodiments of the present invention may be modified or omitted within the scope of the invention.

1 Outdoor air VAV unit 2a Cold water valve (valve)
2b Hot water valve (valve)
Reference Signs List 3: Humidification valve 4: Air conditioner 5: Temperature sensor 6: Temperature sensor 7: Supply air VAV unit 8: Exhaust fan 9: Return air fan 10: Return air damper 11: Exhaust VAV unit 12: Temperature and humidity sensor 13: _CO2 sensor 14 _{: CO2} sensor 15: Person detection sensor 16: Controller 17: Outdoor air duct 18: Outdoor air vent 19a: Cold water supply path (supply path)
19b Hot water supply path (supply path)
20 Supply path 21 Intake duct 22 Intake port 23 Exhaust port 24 Vent 25 Return air duct 26 Return air port 27 Exhaust port 101a, 101b Private room 102 Large room 103 Corridor 104 Small room 401a Chilled water coil (coil)
401b Hot water coil (coil)
402 Humidifier 403 Supply air fan 1601 Operation mode setting unit 1602 Ventilation level setting unit 1603 Outside air volume calculation unit 1604 Ventilation insufficiency determination unit 1605 Setting confirmation unit 1606 Ventilation state determination unit 1607 Valve state determination unit 1608 Outside air volume control unit

Claims (6)

a level setting unit that, by receiving a user input, sets one of a normal level for increasing the proportion of outside air intake when the CO2 concentration is 900 ppm or more and controlling so as not to take in as much outside air as possible when the CO2 concentration is less than 900 ppm, and one or more levels for controlling to increase _the proportion of _outside air contained in the supply air relative to the normal level;
and an outside air volume control unit that controls the ratio of outside air contained in the air supplied to the controlled space generated by the air conditioner based on the level set by the level setting unit. The ventilation control device according to claim 1 , wherein the outdoor air volume control unit is capable of setting the volume of outdoor air taken into the air conditioner to be equal to or greater than a designed outdoor air volume that satisfies a ventilation standard value determined by design. a valve state determination unit that determines a capacity state of a valve that opens and closes a supply path that supplies cold water or hot water for heat exchange to the air conditioner;
The ventilation control device according to claim 2, characterized in that the outdoor air volume control unit increases the amount of outdoor air taken in when the valve state determination unit determines that the controllable characteristic of heat exchange by the valve is not in a capacity insufficient state, and stops increasing the amount of outdoor air taken in or reduces the amount of outdoor air taken in when the valve state determination unit determines that the controllable characteristic of heat exchange by the valve is in a capacity insufficient state. A temperature sensor that measures a temperature of the controlled space;
a valve state determination unit that determines a capacity state of a valve that opens and closes a supply path that supplies cold water or hot water for heat exchange to the air conditioner,
The ventilation control device according to claim 2, characterized in that the outside air volume control unit increases the amount of outside air taken in when the valve state determination unit determines that the controllable characteristic of heat exchange by the valve is not in a state of insufficient capacity or when the temperature measured by the temperature sensor is determined to be below an allowable value, and stops increasing the amount of outside air taken in or reduces the amount of outside air taken in when the valve state determination unit determines that the controllable characteristic of heat exchange by the valve is in a state of insufficient capacity and the temperature measured by the temperature sensor is determined to be equal to or higher than an allowable value. The ventilation control device according to claim 3 or 4, wherein the valve state determination unit determines a capacity state of the valve based on an opening degree of the valve or a flow rate in the supply path. A level setting unit receives a user input and sets one of a normal level for increasing the ratio of the amount of outside air taken in when the CO2 concentration is 900 ppm or more and controlling to take in as little outside air as possible when the CO2 concentration is less than 900 ppm, and one or more levels for controlling to increase the ratio _of outside air _contained in the supply air relative to the normal level;
and a step of an outside air volume control unit controlling a ratio of outside air contained in air supplied to a controlled space generated by an air conditioner based on the level set by the level setting unit.

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