Air-conditioning system

Abstract

Provided is a low-cost air-conditioning system that has a simple configuration. An air-conditioning system (10) comprises: a ventilation unit (1) that has an exhaust fan (13) and an air intake port (11a) and sucks in air through the air intake port (11a) in association with the exhaust fan (13) being driven; an intake duct (4); a plurality of intake-side dampers (51, 52, 53, … , 5n); a carbon dioxide concentration sensor 2; and a control device. The control device opens the intake-side damper of the plurality of intake-side dampers (51, 52, 53, … , 5n) that corresponds to a room for which carbon dioxide concentration is to be detected, closes the remaining intake-side dampers, and drives the exhaust fan. The carbon dioxide concentration sensor 2 is provided to a merge pipe (4b) of the intake duct (4), a passage that conducts air inside the ventilation unit (1) downstream of the merge pipe (4b), or an exhaust duct (6) that conducts air downstream of the ventilation unit (1).

Description

Air conditioning system

[0001] The present disclosure relates to air conditioning systems.

[0002] In recent years, with the spread of infections such as COVID-19, it has become recommended to maintain good indoor air quality (IAQ) in a room. For example, a technology for maintaining good indoor air quality by ventilating a room is known, as described in Patent Document 1.

[0003] That is, Patent Document 1 describes a ventilation control device that includes "a level setting unit that sets a level based on at least one of the indicators of the environment and energy consumption of the space to be controlled, and an outside air volume control unit that controls the proportion of outside air contained in the air supplied to the space to be controlled, generated by an air conditioner, based on the level set by the level setting unit."

[0004] Japanese Patent Application Laid-Open No. 2022-085774

[0005] In the technology described in Patent Document 1, when detecting the carbon dioxide concentration in a predetermined room, ２ In this way, when the carbon dioxide concentration in each of the multiple rooms is to be detected individually, the CO ２ The installation of sensors increases costs and complicates the system.

[0006] Therefore, an object of the present disclosure is to provide an air conditioning system with a low cost and simple configuration.

[0007] In order to solve the above-mentioned problems, the air conditioning system according to the present disclosure includes an air conditioning unit having a first fan and an air intake port, and drawing in air through the air intake port as the first fan is driven; a first duct connecting the air intake port to each of a plurality of rooms; a plurality of first dampers provided in the first duct corresponding to each of the plurality of rooms; a sensor that detects a predetermined indicator of indoor air quality of at least some of the plurality of rooms; and a control unit that, when the sensor detects the predetermined indicator, opens a first damper of the plurality of first dampers that corresponds to the room for which the predetermined indicator is to be detected and closes the remaining first dampers, thereby driving the first fan; and the sensor is provided in a junction pipe of the first duct, in a flow path through which air inside the air conditioning unit flows downstream of the junction pipe, or in an exhaust duct through which air flows downstream of the air conditioning unit.

[0008] According to the present disclosure, it is possible to provide an air conditioning system with a low cost and simple configuration.

[0009] FIG. 1 is a configuration diagram of an air conditioning system according to an embodiment. FIG. 2 is a schematic cross-sectional view of a ventilation unit of the air conditioning system according to an embodiment. FIG. 3 is a functional block diagram of the air conditioning system according to an embodiment. FIG. 4 is a flowchart of processing executed by a control device regarding detection of carbon dioxide concentration in each room in the air conditioning system according to an embodiment. FIG. 5 is an explanatory diagram showing the state of each suction side damper when detecting carbon dioxide concentration in the air conditioning system according to an embodiment. FIG. 6 is an explanatory diagram of a case where carbon dioxide concentration in room R1 is detected in the air conditioning system according to an embodiment. FIG. 7 is a configuration diagram of an air conditioning system according to a first modified example. FIG. 8 is a configuration diagram of an air conditioning system according to a second modified example. FIG. 9 is a configuration diagram of an air conditioning system according to a third modified example.

[0010] <Embodiment> <Configuration of Air Conditioning System> FIG. 1 is a configuration diagram of an air conditioning system 10 according to an embodiment. The air conditioning system 10 shown in FIG. 1 is a system for ventilating multiple rooms R1, R2, R3, ..., Rn. Examples of facilities that include multiple rooms R1, R2, R3, ..., Rn include office buildings and residences (including detached houses and apartment buildings), as well as factories, warehouses, commercial facilities, complexes, and accommodation facilities. In the example of FIG. 1, the multiple rooms R1, R2, R3, ..., Rn are arranged adjacent to each other in sequence, but these rooms R1, R2, R3, ..., Rn do not necessarily have to be adjacent to each other in sequence. Furthermore, room ventilation is also considered to be included in "air conditioning."

[0011] As shown in Fig. 1, the air conditioning system 10 includes a ventilation unit 1 (air conditioning unit), a carbon dioxide concentration sensor 2 (sensor), and a control device 3 (control unit: see Fig. 3). The air conditioning system 10 also includes, as components related to exhaust from rooms R1, R2, R3, ..., Rn, an intake duct 4 (first duct), intake side dampers 51, 52, 53, ..., 5n (first dampers), and an exhaust duct 6. The air conditioning system 10 also includes, as components related to supplying air to rooms R1, R2, R3, ..., Rn, an outside air duct 7, an intake duct 8 (second duct), and intake side dampers 91, 92, 93, ..., 9n (second dampers).

[0012] The ventilation unit 1 is a device that ventilates rooms R1, R2, R3, ..., Rn. That is, the ventilation unit 1 exhausts air from rooms R1, R2, R3, ..., Rn to the outdoors and supplies fresh outdoor air (outdoor air) to rooms R1, R2, R3, ..., Rn. The ventilation unit 1 also has the function of exchanging heat between the air from rooms R1, R2, R3, ..., Rn and the fresh outdoor air. Such a ventilation unit 1 is installed, for example, in the attic space or machine room (not shown) of a facility (not shown) that includes rooms R1, R2, R3, ..., Rn.

[0013] The carbon dioxide concentration sensor 2 is a sensor for sequentially detecting the carbon dioxide concentration (a predetermined indicator of indoor air quality) in rooms R1, R2, R3, ..., Rn. In the example of FIG. 1 , the carbon dioxide concentration sensor 2 is provided inside the ventilation unit 1. Note that the carbon dioxide concentration in each of rooms R1, R2, R3, ..., Rn often varies depending on the volume of the room as well as the number of occupants and their activity levels. For example, even if rooms R1 and R2 have the same volume, if room R2 has a larger number of occupants and a larger activity level than room R1, the amount of carbon dioxide generated by the human body will be greater, resulting in a relatively higher carbon dioxide concentration in room R2.

[0014] The intake duct 4 (first duct) is a duct that connects the air intake port 11a of the ventilation unit 1 to each of the multiple rooms R1, R2, R3, ..., Rn. As shown in FIG. 1, the intake duct 4 includes a branch pipe 4a and a junction pipe 4b. The branch pipe 4a is a duct that guides air from each of the rooms R1, R2, R3, ..., Rn to the junction pipe 4b. The junction pipe 4b is a duct where the air guided from each of the rooms R1, R2, R3, ..., Rn via the branch pipe 4a joins. As shown in FIG. 1, the downstream end of the junction pipe 4b is inserted into the air intake port 11a of the ventilation unit 1.

[0015] The suction-side damper 51 shown in Fig. 1 has the function of adjusting the flow rate of air exhausted from room R1. That is, when an exhaust fan 13 (see Fig. 2) described below is driven at a predetermined rotational speed, the greater the opening of the suction-side damper 51, the greater the amount of air exhausted per unit time from room R1. The same applies to the remaining suction-side dampers 52, 53, ..., 5n. For example, a VAV (Variable Air Volume System) damper is used as such suction-side dampers 51, 52, 53, ..., 5n.

[0016] 1 , a plurality of suction side dampers 51, 52, 53, ..., 5n (first dampers) are provided in the suction duct 4 (first duct) so as to correspond to each of the plurality of rooms R1, R2, R3, ..., Rn. For example, the suction side damper 51 is provided in the suction duct 4 so as to correspond to room R1. Similarly, the remaining suction side dampers 52, 53, ..., 5n correspond to rooms R2, R3, ..., Rn, in that order. The plurality of suction side dampers 51, 52, 53, ..., 5n also have the function of switching between communication and cut-off between the ventilation unit 1 and each of the plurality of rooms R1, R2, R3, ..., Rn.

[0017] For example, when the exhaust fan 13 (see FIG. 2) is driven with the suction-side dampers 51, 52, 53, ..., 5n opened to a predetermined position, the air from each of the rooms R1, R2, R3, ..., Rn is guided to the air suction port 11a of the ventilation unit 1 via the suction duct 4. The air guided to the air suction port 11a exchanges heat in the total heat exchanger 12, and the air after heat exchange is exhausted sequentially via the exhaust port 11b and the exhaust duct 6. The exhaust duct 6 is a duct for exhausting the air that has undergone heat exchange in the total heat exchanger 12, and is inserted into the exhaust port 11b of the ventilation unit 1.

[0018] The outside air duct 7 shown in FIG. 1 is a duct that guides fresh outside air to the outside air intake 11c of the ventilation unit 1 and is inserted into the outside air intake 11c. The supply air duct 8 (second duct) is a duct that connects the air intake port 11d of the ventilation unit 1 (air conditioning unit) to each of the multiple rooms R1, R2, R3, ..., Rn. The supply air duct 8 is configured to include a main duct 8a and a branch duct 8b. The main duct 8a is a duct through which air flowing out through the air intake port 11d of the ventilation unit 1 flows. As shown in FIG. 1, the upstream end of the main duct 8a is inserted into the air intake port 11d of the ventilation unit 1. The branch duct 8b is a duct that guides the air flowing through the main duct 8a to each of the rooms R1, R2, R3, ..., Rn.

[0019] The intake air damper 91 shown in Fig. 1 has the function of adjusting the air volume when air is supplied from the ventilation unit 1 to the room R1. That is, when the intake air fan 14 (see Fig. 2) described below is driven at a predetermined rotational speed, the greater the opening of the intake air damper 91, the greater the volume of air supplied from the ventilation unit 1 to the room R1. The same applies to the remaining intake air dampers 92, 93, ..., 9n. For example, a VAV (Variable Air Volume System) damper is used as such intake air dampers 91, 92, 93, ..., 9n.

[0020] 1 , a plurality of suction-side dampers 51, 52, 53, ..., 5n (second dampers) are provided in the air supply duct 8 (second duct) so as to correspond to each of the plurality of rooms R1, R2, R3, ..., Rn. For example, the air supply damper 91 is provided in the air supply duct 8 so as to correspond to room R1. Similarly, the remaining air supply dampers 92, 93, ..., 9n correspond to rooms R2, R3, ..., Rn, in that order. The plurality of air supply dampers 91, 92, 93, ..., 9n also have the function of switching between communication and cut-off between the ventilation unit 1 and each of the plurality of rooms R1, R2, R3, ..., Rn.

[0021] Fig. 2 is a schematic cross-sectional view of the ventilation unit 1. The outline arrows in Fig. 2 indicate the direction of air flow. As shown in Fig. 2, the ventilation unit 1 (air conditioning unit) includes a housing 11, a total heat exchanger 12, an exhaust fan 13 (first fan), and an intake fan 14 (second fan).

[0022] The housing 11 is a housing that houses the total heat exchanger 12, the exhaust fan 13, and the supply fan 14. The housing 11 has an air inlet 11a to which the intake duct 4 (see FIG. 1) is connected, and an exhaust port 11b to which the exhaust duct 6 (see FIG. 1) is connected. The housing 11 also has an outside air intake 11c to which the outside air duct 7 (see FIG. 1) is connected, and an air supply port 11d to which the supply air duct 8 (see FIG. 1) is connected.

[0023] The total heat exchanger 12 is a heat exchanger that exchanges heat (exchanges sensible heat and latent heat) between fresh air from outdoors and air from rooms R1, R2, R3, ..., Rn (see FIG. 1). In the example of FIG. 2, the total heat exchanger 12 has a rectangular prism shape and is installed so as to divide the interior space of the housing 11 into four regions 15a, 15b, 15c, and 15d. The region 15a shown in FIG. 2 is a space for guiding air flowing in through the air intake 11a to the total heat exchanger 12. Another region 15b is a space for guiding air that has undergone heat exchange in the total heat exchanger 12 to the exhaust vent 11b. The region 15c is a space for guiding fresh air from outdoors to the total heat exchanger 12 through the outside air intake 11c. The other region 15d is a space for guiding air that has undergone heat exchange in the total heat exchanger 12 to the air supply vent 11d.

[0024] In the example of Fig. 2, the carbon dioxide concentration sensor 2 is provided in the region 15a of the housing 11. In other words, the carbon dioxide concentration sensor 2 (sensor) is provided in the "flow path" through which air flows inside the ventilation unit 1 (air conditioning unit) downstream of the junction pipe 4b (see Fig. 1) of the intake duct 4 (first duct: see Fig. 1). Note that the internal space of the cylinder that forms the air intake port 11a is also included in the "flow path" described above.

[0025] The exhaust fan 13 (first fan) shown in FIG. 2 is a fan that is driven to exhaust air from rooms R1, R2, R3, ..., Rn (see FIG. 1) and is provided in region 15b of the ventilation unit 1. When the exhaust fan 13 is driven, air is drawn into the ventilation unit 1 (air conditioning unit) through the air intake port 11a. More specifically, air from rooms R1, R2, R3, ..., Rn (see FIG. 1) is guided to the total heat exchanger 12 via the intake duct 4 (see FIG. 1) and the air intake port 11a. The air that has undergone heat exchange in the total heat exchanger 12 is exhausted outdoors via the exhaust port 11b and the exhaust duct 6 (see FIG. 1) in that order.

[0026] The supply air fan 14 (second fan) shown in FIG. 2 is a fan that is driven when supplying air to rooms R1, R2, R3, ..., Rn (see FIG. 1) and is provided in region 15d of ventilation unit 1. When supply air fan 14 is driven, fresh outdoor air is guided to total heat exchanger 12 via outside air duct 7 (see FIG. 1) and outside air intake port 11c in sequence. The air that has exchanged heat in total heat exchanger 12 flows out into supply air duct 8 (see FIG. 1) via air intake port 11d of ventilation unit 1 (air conditioning unit). The air flowing through supply air duct 8 is then supplied to each of rooms R1, R2, R3, ..., Rn (see FIG. 1).

[0027] While the ventilation unit 1 is operating, the exhaust fan 13 and the supply air fan 14 usually rotate at approximately the same speed, but depending on the operating mode, the exhaust fan 13 and the supply air fan 14 may be driven at different speeds.

[0028] Figure 3 is a functional block diagram of the air conditioning system 10. The control device 3 shown in Figure 3 is configured to include electronic circuits such as a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various interfaces (not shown). The CPU reads out programs stored in the ROM and loads them into the RAM, and the CPU executes various processes. The control device 3 may be built into the ventilation unit 1 (see Figure 2) or may be provided external to the ventilation unit 1.

[0029] The control device 3 receives predetermined operation signals from the remote control Re and also receives momentary detection values ​​from the carbon dioxide concentration sensor 2. Note that sensors other than the carbon dioxide concentration sensor 2 may be added as appropriate. Based on the operation signals from the remote control Re and the detection values ​​from the carbon dioxide concentration sensor 2, the control device 3 controls the exhaust fan 13 and the supply fan 14 in a predetermined manner, as well as the suction-side dampers 51, 52, 53, ..., 5n and the supply-side dampers 91, 92, 93, ..., 9n in a predetermined manner. Specifically, the higher the detected carbon dioxide concentration in room R1 during ventilation operation, the greater the opening degree of the suction-side damper 51 and the supply-side damper 91. This promotes ventilation of room R1. Note that the same applies to the ventilation of the remaining rooms R2, R3, ..., Rn.

[0030] <Processing of Air Conditioning System> Figure 4 is a flowchart of the processing executed by the control device regarding detection of the carbon dioxide concentration in each room (see also Figure 1 as appropriate). Note that the series of processing shown in Figure 4 may be performed before the start of ventilation operation by the ventilation unit 1, or may be performed while ventilation operation is being performed. In the following example, a case will be described in which the carbon dioxide concentration in each of rooms R1, R2, R3, ..., Rn is detected, but it is also possible to detect the carbon dioxide concentration in some of rooms R1, R2, R3, ..., Rn (for example, rooms R1, R2, R3).

[0031] In step S101, control device 3 drives exhaust fan 13 (see FIG. 2). Note that, although control of supply air fan 14 is not shown in FIG. 4, it may be performed as follows. That is, when control device 3 (controller) detects the carbon dioxide concentration (a predetermined index of indoor air quality) with carbon dioxide concentration sensor 2 (sensor), control device 3 (controller) may either keep supply air fan 14 (second fan) stopped or drive supply air fan 14.

[0032] When the control device 3 keeps the supply air fan 14 stopped, air is hardly supplied to the rooms R1, R2, R3, ..., Rn, regardless of the open / closed state of the supply air dampers 91, 92, 93, ..., 9n. Therefore, in this case, each of the supply air dampers 91, 92, 93, ..., 9n may be in either an open or closed state. The case where the supply air fan 14 is driven while detecting the carbon dioxide concentration in a specific room will be described later.

[0033] Next, in step S102, the control device 3 sets k=1. Here, "k" is a value that is incremented when the control device 3 switches the room for which the carbon dioxide concentration is to be detected (S106). In step S103, the control device 3 opens the suction side damper corresponding to room Rk and closes the remaining suction side dampers. For example, when k=1, the control device 3 opens the suction side damper 51 corresponding to room R1 and closes the remaining suction side dampers 52, 53, ..., 5n.

[0034] When the exhaust fan 13 (see FIG. 2) is driven in this state, the air in room R1 is guided to the ventilation unit 1 via the suction duct 4. On the other hand, for the remaining rooms R2, R3, ..., Rn, the suction-side dampers 52, 53, ..., 5n are closed, so that the air is hardly guided to the ventilation unit 1. Therefore, the carbon dioxide concentration sensor 2 installed in the ventilation unit 1 can detect the carbon dioxide concentration in room R1.

[0035] In this way, when detecting the carbon dioxide concentration (a predetermined index of indoor air quality) of a predetermined room with carbon dioxide concentration sensor 2, control device 3 (controller) opens the suction-side damper of the multiple suction-side dampers 51, 52, 53, ... 5n (first dampers) that corresponds to the room for which carbon dioxide concentration is to be detected, closes the remaining suction-side dampers, and drives exhaust fan 13 (first fan). This allows the carbon dioxide concentration of each of rooms R1, R2, ... , Rn to be detected with a single carbon dioxide concentration sensor 2, thereby reducing costs and simplifying the configuration.

[0036] In step S104, the control device 3 detects the carbon dioxide concentration of room Rk. That is, the control device 3 stores the detected value of the carbon dioxide concentration sensor 2 as the carbon dioxide concentration of room Rk. For example, the control device 3 stores the detected value of the carbon dioxide concentration sensor 2 when the suction side damper 51 is in the open state and the remaining suction side dampers 52, 53, ..., 5n are in the closed state as the detected value of the carbon dioxide concentration of room R1.

[0037] In step S105, the control device 3 determines whether the value of k is equal to n. Here, "n" is a value indicating the number of rooms R1, R2, R3, ..., Rn for which carbon dioxide concentration detection is to be performed. If the value of k is not equal to n in step S105 (S105: No), the processing by the control device 3 proceeds to step S106. In other words, if there is a room for which carbon dioxide concentration detection has not yet been performed, the processing by the control device 3 proceeds to step S106.

[0038] In step S106, the control device 3 increments the value of k. After performing the process of step S106, the control device 3 returns to step S103. In this way, the control device 3 sequentially switches the room whose carbon dioxide concentration is to be detected. For example, when switching the room whose carbon dioxide concentration is to be detected from room R1 to room R2, the control device 3 switches the suction side damper 51 corresponding to room R1 from the open state to the closed state, while switching another suction side damper 52 corresponding to room R2 from the closed state to the open state. The control device 3 also maintains the suction side dampers 53, ..., 5n corresponding to the remaining rooms R3, ..., Rn in the closed state. As a result, air from room R2 is guided to the ventilation unit 1 via the suction duct 4.

[0039] If the value of k is equal to n in step S105 (S105: Yes), the process by the control device 3 proceeds to step S107. That is, when the carbon dioxide concentrations of the rooms R1, R2, R3, ..., Rn have been detected, the process by the control device 3 proceeds to step S107.

[0040] In step S107, the control device 3 determines whether a predetermined time has elapsed. That is, the control device 3 determines whether a predetermined time has elapsed since the completion of detection of the carbon dioxide concentration in each of rooms R1, R2, R3, ..., Rn. The predetermined time is a cycle (e.g., one hour) when the series of processes shown in FIG. 4 is performed, and is set in advance. If the predetermined time has not elapsed in step S107 (S107: No), the control device 3 repeats the process of step S107. If the predetermined time has elapsed in step S107 (S107: Yes), the process of the control device 3 returns to "START" (RETURN).

[0041] Note that the flowchart in Figure 4 describes a case in which the control device 3 continues to drive the exhaust fan 13 (see Figure 2) while sequentially detecting the carbon dioxide concentrations of rooms R1, R2, R3, ..., Rn, but this is not limited to this. For example, the control device 3 may temporarily stop the exhaust fan 13 when switching the open / close state of at least one of the suction side dampers 51, 52, 53, ..., 5n. After switching the open / close state of at least one of the suction side dampers 51, 52, 53, ..., 5n, the control device 3 drives the exhaust fan 13 again. This prevents a large load from being placed on the suction side dampers 51, 52, 53, ..., 5n when switching the open / close state.

[0042] 5 is an explanatory diagram showing the state of each suction-side damper when detecting the carbon dioxide concentration (see also FIG. 1 as needed). Each column in FIG. 5 detects the carbon dioxide concentration of a specific room (for example, room R1) (CO ２ 5 shows the open / closed states of suction side dampers 51, 52, 53, ..., 5n when detecting the airflow. Also, "open" indicated by a bold frame in FIG. 5 indicates that a specific suction side damper is in the open state. Here, the "open" state of the suction damper does not necessarily have to be fully open, as long as air can flow through the suction side damper. Also, "closed" shown in FIG. 5 indicates that a specific suction side damper is in the closed state.

[0043] In FIG. 5 , "suction side damper of room R1" refers to the suction side damper 51 corresponding to room R1. The same applies to the suction side dampers of the remaining rooms R2, R3, ..., Rn. For example, when detecting the carbon dioxide concentration of room R1, the control device 3 opens the suction side damper 51 of room R1 and closes the suction side dampers 52, 53, ..., 5n of the remaining rooms R2, R3, ..., Rn. This allows the carbon dioxide concentration of room R1 to be detected by the carbon dioxide concentration sensor 2 provided in the ventilation unit 1. In the same manner, the control device 3 sequentially switches between rooms R1, R2, R3, ..., Rn as the room to be subjected to carbon dioxide concentration detection.

[0044] FIG. 6 is an explanatory diagram illustrating the case where the carbon dioxide concentration in room R1 is detected. In the flowchart (see FIG. 4 ), the intake air fan 14 is assumed to be stopped during carbon dioxide concentration detection. However, the following process may be performed. For example, when detecting the carbon dioxide concentration in room R1, the control device 3 may drive the exhaust fan 13 (see FIG. 2 ) and the intake air fan 14 (see FIG. 2 ). More specifically, when the control device 3 (controller) detects the carbon dioxide concentration (a predetermined indicator of indoor air quality) using the carbon dioxide concentration sensor 2 (sensor), it closes the intake air damper 91 (second dampers) corresponding to the room R1 whose carbon dioxide concentration is to be detected, and drives the intake air fan 14 (second fan; see FIG. 2 ).

[0045] This makes it possible to prevent air from flowing into room R1 through air supply duct 8 when detecting the carbon dioxide concentration in room R1. Therefore, the actual carbon dioxide concentration in room R1 does not gradually decrease during detection of the carbon dioxide concentration, and the carbon dioxide concentration can be detected with high accuracy.

[0046] 6, all of the intake air dampers 92, 93, ..., 9n of rooms R2, R3, ..., Rn that are not targets for carbon dioxide concentration detection are open, but this is not limiting. For example, while detecting the carbon dioxide concentration in room R1, some of the intake air dampers 92, 93, ..., 9n may be closed and the rest may be open. In short, it is sufficient to prevent new outside air from being supplied to room R1 when detecting the carbon dioxide concentration in room R1.

[0047] Furthermore, the control device 3 (controller) may repeatedly detect the carbon dioxide concentration (predetermined index) during a "period" during which each of the plurality of suction-side dampers 51, 52, 53, ..., 5n (first dampers) remains open or closed. In this case, the control device 3 may weight the detected carbon dioxide concentration (predetermined index) more heavily in the latter half of the "period" than in the first half. For example, assume that the period during which the suction-side damper 51 is open and the remaining suction-side dampers 52, 53, ..., 5n are closed is set to one minute, and detected values ​​are acquired every second (60 detected values ​​are acquired for room R1). In this case, the control device 3 may weight the detected carbon dioxide concentration values ​​obtained in the latter 30 seconds more heavily than the detected carbon dioxide concentration values ​​obtained in the first 30 seconds. A predetermined weighting coefficient multiplied by the detected carbon dioxide concentration may be used as the "weighting."

[0048] For example, when detecting the carbon dioxide concentration in room R1 and then detecting the carbon dioxide concentration in another room R2, immediately after switching the states of the suction-side dampers 51, 52, 53, ..., 5n, air from room R1 remains in the suction duct 4. After that, the air remaining in the suction duct 4 (air from room R1) is exhausted to the outside by driving the exhaust fan 13. Therefore, by weighting the detection values ​​in the latter half of the aforementioned "period" more heavily than in the first half, the carbon dioxide concentration in room R2 can be detected with high accuracy.

[0049] In addition, when the "period" during which each of the suction-side dampers 51, 52, 53, ..., 5n remains open or closed is one minute, the control device 3 may store the average of the carbon dioxide concentration detection values ​​for the latter 30 seconds (a total of 30 detection values ​​per second) as the carbon dioxide concentration of the specified room, instead of using the carbon dioxide concentration detection values ​​for the first 30 seconds (a total of 30 detection values ​​per second). Such processing is also included in the matter of weighting the carbon dioxide concentration detection values ​​more heavily in the latter half of the "period" than in the first half.

[0050] Furthermore, when the "period" during which each of the suction-side dampers 51, 52, 53, ..., 5n remains open or closed is one minute, the last one of the detected values ​​(or the average value of multiple detected values) obtained in the latter 30 seconds (a total of 30 detected values ​​per second) may be stored as the detected value of the carbon dioxide concentration, instead of using the detected value of the carbon dioxide concentration in the first 30 seconds. Such processing is also included in the matter of weighting the detected value of the carbon dioxide concentration more heavily in the latter half of the "period" than in the first half.

[0051] According to this embodiment, the carbon dioxide concentration in each of the rooms R1, R2, R3, ..., Rn is detected sequentially using the carbon dioxide concentration sensor 2 provided in the ventilation unit 1. Therefore, there is no particular need to provide a carbon dioxide concentration sensor 2 in each of the rooms R1, R2, R3, ..., Rn, and only one carbon dioxide concentration sensor 2 is required, which simplifies the configuration of the air conditioning system 10 and reduces costs.

[0052] While the air conditioning system 10 according to the present disclosure has been described above in the embodiments, the present disclosure is not limited to these descriptions and various modifications can be made. For example, while the embodiment has described a case in which the carbon dioxide concentration sensor 2 is provided in the ventilation unit 1, the present disclosure is not limited to this. That is, as will be described next, the carbon dioxide concentration sensor 2 may be provided in the junction pipe 4b (see FIG. 7) of the intake duct 4.

[0053] FIG. 7 is a configuration diagram of an air conditioning system 10A according to a first modified example. While FIG. 7 illustrates the carbon dioxide concentration sensor 2 outside the junction pipe 4b of the intake duct 4, the carbon dioxide concentration sensor 2 is actually installed inside (e.g., on the inner wall surface of) the junction pipe 4b of the intake duct 4 so that the carbon dioxide concentration can be detected. In this way, even when the carbon dioxide concentration sensor 2 is installed in the junction pipe 4b of the intake duct 4 (first duct) instead of the ventilation unit 1, the same effects as those of the embodiment can be achieved. The carbon dioxide concentration sensor 2 and the control device 3 (see FIG. 3) may be connected via wiring, or may communicate with each other wirelessly.

[0054] FIG. 8 is a configuration diagram of an air conditioning system 10B according to a second modification. While FIG. 8 illustrates the carbon dioxide concentration sensor 2 outside the exhaust duct 6, the carbon dioxide concentration sensor 2 is actually installed inside the exhaust duct 6 (e.g., on the inner wall surface) so that the carbon dioxide concentration can be detected. As shown in FIG. 8 , a configuration in which the carbon dioxide concentration sensor 2 is installed in the exhaust duct 6 through which air flows downstream of the ventilation unit 1 (air conditioning unit) also achieves the same effects as the embodiment. In this way, the carbon dioxide concentration sensor 2 (sensor) may be installed in the junction pipe 4b of the intake duct 4 (first duct), in the flow path through which air flows inside the ventilation unit 1 (air conditioning unit) downstream of the junction pipe 4b, or in the exhaust duct 6 through which air flows downstream of the ventilation unit 1 (air conditioning unit).

[0055] Fig. 9 is a diagram showing the configuration of an air conditioning system 10C according to a third modification. The air conditioning system 10C shown in Fig. 9 has a configuration in which the intake duct 8 (see Fig. 1) and intake-side dampers 91, 92, 93, ..., 9n (see Fig. 1) are omitted from the configuration described in the embodiment. Furthermore, the junction pipe 4b of the intake duct 4 is inserted into the air intake port 11a of the ventilation unit 1C, and the exhaust duct 6 is inserted into the exhaust port 11b. The ventilation unit 1C is equipped with an exhaust fan (not shown).

[0056] As the exhaust fan (not shown) is driven, air drawn into the ventilation unit 1C through the intake duct 4 is exhausted through the exhaust duct 6. A carbon dioxide concentration sensor 2 is provided downstream of the junction pipe 4b in the flow path through which air flows inside the ventilation unit 1C. As in the embodiment (FIGS. 4 and 5), the control device (not shown) of the ventilation unit 1C opens the intake-side damper corresponding to the room whose carbon dioxide concentration is to be detected and closes the remaining intake-side dampers, and then drives the exhaust fan (not shown). The control device then sequentially switches between rooms whose carbon dioxide concentration is to be detected. Even with this configuration, a single carbon dioxide concentration sensor 2 can detect the carbon dioxide concentration in each of rooms R1, R2, R3, ..., Rn.

[0057] Furthermore, in the embodiment, the carbon dioxide concentration sensor 2 is installed in the suction-side region 15a (see FIG. 2) of the housing 11 of the ventilation unit 1, but this is not limited thereto. For example, the carbon dioxide concentration sensor 2 may be installed in the exhaust-side region 15b instead of the suction-side region 15a. Because the carbon dioxide concentration in the exhaust-side region 15b is substantially equal to the carbon dioxide concentration in the suction-side region 15a, such a configuration achieves the same effects as the embodiment. Note that the region 15b (see FIG. 2) of the housing 11 is included in the "flow path" through which air flows inside the ventilation unit 1 (air conditioning unit) downstream of the junction pipe 4b. The internal space of the cylinder forming the exhaust port 11b is also included in the "flow path."

[0058] Furthermore, in the embodiment, the case where the control device 3 (controller) sequentially switches between rooms R1, R2, R3, ..., Rn as the detection target for carbon dioxide concentration (a predetermined indicator of indoor air quality) is described. However, this is not limited to this. That is, the carbon dioxide concentration sensor 2 (sensor) may be used to detect the carbon dioxide concentration (a predetermined indicator of indoor air quality) of at least some of the rooms R1, R2, R3, ..., Rn. In this case, the control device 3 (controller) sequentially switches between rooms R1, R2, R3, ..., Rn as the detection target for carbon dioxide concentration (a predetermined indicator of indoor air quality) for at least some of the rooms R1, R2, R3, ..., Rn. This type of processing also achieves the same effects as the embodiment.

[0059] Furthermore, in the ventilation unit 1 (see FIG. 1 ) described in the embodiment, a direct expansion coil (not shown) may be provided downstream of the air supply fan 14. The direct expansion coil is a heat exchanger that exchanges heat between the air flowing from the total heat exchanger 12 toward the air supply port 11d and the refrigerant. By providing such a direct expansion coil, air whose temperature has been adjusted to a predetermined value can be supplied to the rooms R1, R2, R3, ..., Rn.

[0060] In the embodiment, the air conditioning system 10 (see FIG. 1 ) includes the ventilation unit 1 (see FIG. 1 ). However, this is not limiting. For example, the air conditioning system may include a heat source unit (not shown) including a compressor, an expansion valve, an outdoor fan, and an outdoor heat exchanger, and an air conditioning unit including a fan and a heat exchanger. In such an air conditioning system, a refrigerant circulates sequentially through the compressor, the outdoor heat exchanger, the expansion valve, and the heat exchanger. Heat exchange occurs between air drawn into the air conditioning unit through the intake duct and the refrigerant flowing through the heat exchanger of the air conditioning unit. The heat-exchanged air is then supplied to each of the rooms R1, R2, R3, ..., Rn through the supply duct. Control of the multiple intake-side dampers provided in the intake duct and the multiple supply-side dampers provided in the supply duct is the same as in the embodiment, and therefore will not be described here.

[0061] Furthermore, the heat source unit (not shown) may be a unit (a so-called chiller) configured to adjust the temperature of air returning from an air conditioning unit (not shown) by heat exchange with cold or hot water. The embodiments can also be applied to various other types of air conditioning systems. Furthermore, undercut portions of doors (not shown) installed in the partition walls of adjacent rooms may be used instead of the air supply duct 8 (see FIG. 1 ) described in the embodiments. In this case, air is supplied to each room sequentially via the undercut portions of the doors.

[0062] In the embodiment, the carbon dioxide concentration sensor 2 detects the carbon dioxide concentration in each of the rooms R1, R2, R3, ..., Rn. However, this is not limited to this. For example, the "predetermined indicator of indoor air quality" may be the temperature, humidity, or concentration of suspended particulate matter in the air of the room to be detected, or the concentration of the refrigerant used for air conditioning. The "suspended particulate matter" may be, for example, an air pollutant such as PM2.5. Furthermore, when detecting the concentration of the refrigerant, for example, a refrigerant sensor (not shown) that detects refrigerant leakage from the refrigerant piping of the air conditioning unit is used.

[0063] Furthermore, multiple types of indicators of indoor air quality may be detected. For example, the predetermined indicator of indoor air quality may be at least one of the carbon dioxide concentration, temperature, humidity, concentration of suspended particulate matter in the air, and concentration of the refrigerant used for air conditioning in the room to be detected. Other indicators that may be included as "predetermined indicators of indoor air quality" include, for example, oxygen concentration and carbon monoxide concentration in the air, as well as the concentration of combustible gases such as methane and other hydrocarbons, the amount of specified bacteria or viruses in the air, the amount of dust, and specific odors.

[0064] The embodiment and the first, second, and third modified examples may be combined as appropriate. For example, the carbon dioxide concentration sensor 2 may be provided in the region 15a (see FIG. 2) of the ventilation unit 1 (air conditioning unit), a humidity sensor (not shown) may be provided in the junction pipe 4b (see FIG. 1) of the intake duct 4, and a refrigerant sensor (not shown) may be provided in the exhaust duct 6. In addition, various combinations of sensor types and installation locations are possible.

[0065] Furthermore, each embodiment has been described in detail to clearly explain the present disclosure, and is not necessarily limited to having all of the described configurations. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. Furthermore, the above-described mechanisms and configurations are those considered necessary for explanation, and do not necessarily represent all mechanisms and configurations of the product.

[0066] DESCRIPTION OF SYMBOLS 1, 1C Ventilation unit (air conditioning unit) 2 Carbon dioxide concentration sensor (sensor) 3 Control device (control unit) 4 Intake duct (first duct) 4a Branch pipe 4b Junction pipe 6 Exhaust duct 7 Outdoor air duct 8 Supply air duct (second duct) 10, 10A, 10B, 10C Air conditioning system 11 Housing 11a Air intake port 11b Exhaust port 11c Outdoor air intake port 11d Air supply port 12 Total heat exchanger 13 Exhaust fan (first fan) 14 Supply air fan (second fan) 15a, 15b Area (flow path) 51, 52, 53, ..., 5n Intake side damper (first damper) 91, 92, 93, ..., 9n Supply side damper (second damper) R1, R2, R3, ..., Rn rooms

Claims

1. An air conditioning system comprising an air conditioning unit having a first fan and an air suction port, sucking air through the air suction port with the driving of the first fan, a first duct connecting the air suction port and each of a plurality of rooms, a plurality of first dampers provided in the first duct corresponding to each of the plurality of rooms, a sensor detecting a predetermined index of the indoor air quality of at least a part of the plurality of rooms, and a control unit that, when the sensor detects the predetermined index, opens a first damper corresponding to a room to be detected for the predetermined index among the plurality of first dampers, closes the remaining first dampers, and drives the first fan. The sensor is provided in a confluence pipe of the first duct, a flow path through which air inside the air conditioning unit flows downstream of the confluence pipe, or an exhaust duct through which air flows downstream of the air conditioning unit.

2. The air conditioning system according to claim 1, wherein the control unit sequentially switches the room to be detected for the predetermined index for at least a part of the plurality of rooms.

3. The air conditioning system according to claim 1, wherein the control unit sequentially switches the room to be detected for the predetermined index for all of the plurality of rooms.

4. The air conditioning unit has a second fan that discharges air through an air supply port of the air conditioning unit, and includes a second duct connecting the air supply port and each of the plurality of rooms, and a plurality of second dampers provided in the second duct corresponding to each of the plurality of rooms. The control unit, when the sensor detects the predetermined index, closes a second damper corresponding to a room to be detected for the predetermined index among the plurality of second dampers and drives the second fan. The air conditioning system according to claim 1 is characterized by this.

5. The air conditioning unit has a second fan that discharges air through an air supply port of the air conditioning unit, further includes a second duct connecting the air supply port and each of the plurality of rooms, and the control unit maintains the second fan in a stopped state when the sensor detects the predetermined index. The air conditioning system according to claim 1 is characterized by this.

6. The control unit repeatedly detects the predetermined index during the period in which each of the plurality of first dampers remains in an open state or a closed state, and weights the detection value of the predetermined index more heavily in the second half of the period than in the first half of the period. The air conditioning system according to claim 1, characterized by this.

7. The predetermined index is at least one of the carbon dioxide concentration, temperature, humidity, concentration of suspended particulate matter in the air, and concentration of refrigerant used for air conditioning of the air in the room to be detected. The air conditioning system according to any one of claims 1 to 6, characterized by this.

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