Air conditioning system and pressure loss estimation method for the same

Abstract

To provide an air conditioning system capable of accurately estimating pressure loss from the rotation frequency of a fan.SOLUTION: An air conditioning system 1 is for air conditioning of a living room 5 in a building 2. The air conditioning system 1 includes an air conditioner 6, a duct 7, a fan 8, a fan control unit 15, and a pressure loss estimation unit 16. The fan control unit 15 controls a rotation frequency of the fan 8 so that an air volume of the fan 8 becomes a predefined amount in each of a plurality of notches. The pressure loss estimation unit 16 includes: a rotation frequency acquisition unit 17 for acquiring a rotation frequency RM of the fan 8 during operation with a maximum notch NM; a first estimation unit 21 for estimating the pressure loss of the fan 8 on the basis of the rotation frequency RM when the rotation frequency RM is equal to a threshold value TP or less; and a second estimation unit 22 for estimating the pressure loss on the basis of a first rotation frequency R1 and a second rotation frequency R2 when the rotation frequency RM is larger than the threshold value TP.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an air conditioning system and a method for estimating pressure loss therein. [Background technology]

[0002] For example, in a residential ducted whole-building air conditioning system, conditioned air is transported to rooms through ducts by the power of a fan. In this type of system, significant pressure loss can occur depending on the way the ducts are installed. Therefore, after the system is installed on-site, it is necessary to check whether a predetermined air volume is being achieved when the fan is operating at maximum air volume. Conventionally, this check has been performed by installing an air volume meter at the air outlet in the room to directly measure the air volume, but this requires a great deal of effort.

[0003] In response to this, for example, Patent Document 1 below proposes a method of estimating pressure loss from the rotation speed of a fan. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-033681 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method of estimating pressure loss based on the rotation speed of the fan, the accuracy of the estimation tends to decrease when the rotation speed of the fan is close to the upper limit of the fan's capacity, for example.

[0006] The present invention has been devised in view of the above circumstances, and has as its main object to provide an air conditioning system that can accurately estimate pressure loss from the rotation speed of the fan. [Means for solving the problem]

[0007] The present invention is an air conditioning system for air-conditioning a room in a building, comprising: an air conditioner; a duct for transporting air conditioned by the air conditioner to the room; The air conditioner includes a fan for pressure-feeding the air conditioned by the air conditioner to the room through the duct, a fan control unit for controlling operation of the fan, and a pressure loss estimation unit for estimating pressure loss of the fan, wherein the fan control unit has a plurality of notches and controls the rotation speed of the fan so that the air volume of the fan is a predetermined constant volume at each of the plurality of notches, and the plurality of notches include a maximum notch at which the air volume of the fan is maximum, and a first notch at which the air volume of the fan is smaller than the air volume of the maximum notch. and a second notch, and the pressure loss estimation unit includes: a rotation speed acquisition unit that acquires the rotation speed of the fan while it is operating at the maximum notch; a first estimation unit that, when the acquired rotation speed is equal to or less than a predetermined threshold, estimates the pressure loss of the fan based on the rotation speed; and a second estimation unit that, when the acquired rotation speed is greater than the threshold, estimates the pressure loss based on a first rotation speed that is the rotation speed of the fan while it is operating at the first notch and a second rotation speed that is the rotation speed of the fan while it is operating at the second notch. [Effects of the Invention]

[0008] By employing the above-described configuration, the air conditioning system of the present invention can accurately estimate the pressure loss from the rotation speed of the fan. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view conceptually showing a building in which an air conditioning system according to an embodiment of the present invention is installed. [Figure 2] 1 is a conceptual diagram showing the configuration of an air conditioning system according to an embodiment of the present invention. [Figure 3] FIG. 10 is a scatter plot showing the relationship between time and the number of rotations of the fan for one notch. [Figure 4] 1 is a rotation speed-pressure loss curve showing the relationship between the rotation speed of a fan and pressure loss. [Figure 5] 1 is a graph showing the relationship between the air flow rate of a fan and pressure loss in an air conditioning system. [Figure 6] 3 is a flowchart illustrating a pressure loss estimation method according to the present embodiment. [Figure 7] 10 is a flowchart in which the timings at which the first rotation speed and the second rotation speed are acquired are specified. [Figure 8] 8 is a flowchart in which the timings at which the first rotation speed and the second rotation speed are acquired are identified in a manner different from that of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are intended to illustrate the features of the present invention, but may include exaggerated representations and representations that differ from the dimensional ratios of the actual structure to facilitate understanding of the present invention. Furthermore, identical or common elements are designated by the same reference numerals throughout the embodiments, and redundant explanations will be omitted. Furthermore, the specific configurations shown in the embodiments and drawings are intended to facilitate understanding of the present invention, and the present invention is not limited to the specific configurations shown in the drawings. Furthermore, well-known configurations may be adopted as appropriate for configurations not described in this specification.

[0011] [building] FIG. 1 is a cross-sectional view conceptually showing a building 2 in which an air conditioning system 1 of this embodiment is installed. The building 2 of this embodiment is configured to include an underfloor space 3 and an above-floor space 4. A plurality of rooms 5 are provided in the above-floor space 4. The plurality of rooms 5 of this embodiment includes a first-floor room 5A and a second-floor room 5B. Note that the plurality of rooms 5 may be configured, for example, only with a first-floor room 5A, or may also include rooms on the third floor or higher (not shown), etc.

[0012] [Air conditioning system] FIG. 2 is a conceptual diagram showing the configuration of an air conditioning system 1 of this embodiment. As shown in FIG. 2, the air conditioning system 1 includes a control unit 9 and various devices 10 controlled by the control unit 9. The air conditioning system 1 of this embodiment includes an air conditioner 6 and a fan 8 as the devices 10. The air conditioning system 1 also includes a fan control unit 15 and a pressure loss estimation unit 16 as the control unit 9. The control unit 9 of the air conditioning system 1 includes a known arithmetic unit 25 including a CPU 26, a working memory 27, a storage device 28, etc., and the operation of the fan control unit 15 and the pressure loss estimation unit 16, which will be described later, is realized by a program unit 29 of this arithmetic unit 25. Furthermore, although devices that are less relevant to the present invention are omitted in FIGS. 1 and 2, the air conditioning system 1 of the present invention may include known devices.

[0013] [Air conditioner] 1, the air conditioner 6 of this embodiment is configured as, for example, a typical split-type air conditioner for home use. The air conditioner 6 includes an indoor unit 6A and an outdoor unit (not shown) installed outside the building 2 as a set.

[0014] The indoor unit 6A has an inlet 6i and an outlet 6o. The inlet 6i is for taking in air (in this example, a mixture of circulated air Ai and outside air Ao) into a heat exchanger (not shown) provided inside the indoor unit 6A. On the other hand, the outlet 6o is for discharging air Ac that has been conditioned by the heat exchanger (hereinafter may be simply referred to as "conditioned air"). The set temperature and air volume (blowout air volume) of the air conditioner 6 are controlled by, for example, a control unit 9.

[0015] The indoor unit 6A of this embodiment is housed, for example, inside a chamber box 12. The chamber box 12 is formed in a box shape with a space inside. The chamber box 12 of this embodiment is provided with an air supply port (not shown) for supplying air Ai circulated through multiple rooms 5 to the inside, and an outside air intake port (not shown) for supplying outside air (underfloor air) Ao to the inside. The outside air Ao of this embodiment is taken in from the underfloor space 3, for example, via an outside air supply duct 13 and an outside air supply fan 14. Note that the outside air Ao may also be taken in directly from outdoors.

[0016] [duct] The duct 7 of this embodiment is for transporting air Ac conditioned by the air conditioner 6 (hereinafter, sometimes simply referred to as "conditioned air") to the living room 5. The duct 7 of this embodiment is configured to include a first duct 7A and a second duct 7B.

[0017] The first duct 7A is for transporting the conditioned air Ac to the living room 5A on the first floor. One end of the first duct 7A is connected to the air conditioner 6 side (in this example, the air outlet 6o side inside the chamber box 12). The other end of the first duct 7A is connected to the living room 5A on the first floor. This allows the first duct 7A to communicate between the air conditioner 6 (chamber box 12) and the living room 5A on the first floor.

[0018] The second duct 7B is for transporting the conditioned air Ac to the living room 5B on the second floor. One end of the second duct 7B is connected to the air conditioner 6 side (in this example, the air outlet 6o side inside the chamber box 12). The other end of the second duct 7B is connected to the living room 5 on the second floor. This allows the second duct 7B to communicate between the air conditioner 6 (chamber box 12) and the living room 5 on the second floor.

[0019] In this embodiment, the plurality of ducts 7 are configured by the first duct 7A and the second duct 7B, but are not limited to this. For example, if the building 2 has rooms 5 on the third floor or higher, ducts 7 (not shown) communicating with these rooms 5 may be added.

[0020] [fan] The fan 8 of this embodiment is for pressurizing and sending the conditioned air Ac to the multiple rooms 5 through the multiple ducts 7. The fan 8 of this embodiment is housed in a chamber box 12, but is not particularly limited thereto. In this embodiment, the fan 8 is provided in each of the first duct 7A and the second duct 7B.

[0021] [Fan control unit] 2, the fan control unit 15 controls the operation of the fan 8. The fan control unit 15 has a plurality of notches, and controls the rotation speed of the fan 8 so that the air volume of the fan 8 is a predetermined constant amount for each of the plurality of notches.

[0022] The multiple notches include at least a maximum notch NM, a first notch N1, and a second notch N2. The maximum notch NM is a notch at which the airflow rate of the fan 8 is maximum. In this embodiment, the first notch N1 is a notch set to an airflow rate that is one level lower than the airflow rate set for the maximum notch NM. The second notch N2 is a notch set to an airflow rate that is one level lower than the airflow rate set for the first notch N1. In a preferred embodiment, the multiple notches in this embodiment include a third notch N3. The third notch N3 is a notch set to an airflow rate that is one level lower than the airflow rate set for the second notch N2, and in this embodiment, is a notch at which the airflow rate of the fan 8 is minimum. Note that in this embodiment, the airflow rates are set to gradually decrease in the order of the first notch N1, the second notch N2, and the third notch N3. However, this is not particularly limited, and the relationship between the airflow rates can be set arbitrarily as long as the airflow rate is set to a value lower than the airflow rate of the maximum notch NM.

[0023] In this embodiment, the maximum notch air volume is 800 m 3 / h. The first notch has an air volume of 640m 3 / h. The second notch has an air volume of 480m 3 / h. The air volume of the third notch is 170m 3 / h. Note that the number of notches and the airflow rate set for each notch are not limited to this. The switching of the notches is controlled by the fan control unit 15. The fan control unit 15 controls the rotation speed of the fan 8 in accordance with the set temperature and actual temperature of each room 5 so that the airflow rate of the fan 8 is the airflow rate corresponding to each notch.

[0024] FIG. 3 shows a scatter plot illustrating the relationship between time and the fan rotation speed for one notch. In FIG. 3, the horizontal axis represents time (sec) and the vertical axis represents the rotation speed (rpm) of the fan 8. As shown in FIG. 3, immediately after the fan 8 starts operating (t≦100), the rotation speed R varies widely between approximately 1100 and 1200 rpm. On the other hand, after the fan 8 has been operating for a while (t≧160), the variation in the rotation speed becomes smaller and the rotation speed stabilizes between 1110 and 1140 rpm. However, although the rotation speed R of the fan 8 stabilizes after the fan 8 has been operating for a while, if the rotation speed R of the fan 8 is close to the design upper limit of the fan's capacity (pressure loss), it becomes difficult to accurately determine the actual capacity of the fan 8, resulting in a problem of reduced accuracy in estimating the pressure loss of the fan 8. The inventors have found through various experiments that such variations in rotation speed and performance close to the upper limit have adverse effects when estimating the pressure loss of the fan 8, and have completed the present invention.

[0025] [Pressure loss estimation section] 2, the pressure loss estimation unit 16 estimates the pressure loss of the fan 8. From the viewpoint of improving the accuracy, the pressure loss estimation unit 16 of the present invention includes a rotation speed acquisition unit 17, a first estimation unit 21, and a second estimation unit 22.

[0026] [Rotation speed acquisition section] The rotation speed acquisition unit 17 acquires the rotation speed RM of the fan 8 while it is operating at the maximum notch NM. The rotation speed acquisition unit 17 of this embodiment acquires the rotation speed RM of the fan 8, for example, after operation at the maximum notch NM has continued for a predetermined time (for example, 30 to 180 seconds, and 160 seconds in this embodiment). This duration is specified in advance as the time required from when the fan 8 starts operating until the variation in the rotation speed becomes small. This makes it possible to acquire the rotation speed RM while reducing the influence of the variation in the rotation speed shown in FIG. 3. Furthermore, the rotation speed acquisition unit 17 of this embodiment acquires only one piece of data on the rotation speed RM. This makes it possible to save the storage capacity included in the calculation device 25.

[0027] In another embodiment, the rotation speed acquisition unit 17 may continue to acquire the rotation speed of the fan 8 for a predetermined time and determine the rotation speed RM of the fan 8 based on, for example, the average of the acquired data. This acquisition method can further reduce the influence of variations in the rotation speed of the fan 8. Although the rotation speed acquisition unit 17 can acquire the rotation speed RM of the fan 8 when the influence of variations in the rotation speed is reduced, as described above, if the rotation speed RM of the fan 8 is close to the design upper limit of the capacity (pressure loss) of the fan 8, it becomes difficult to accurately determine the actual capacity of the fan 8, and the estimation accuracy of the pressure loss of the fan 8 may be reduced. For this reason, the first estimating unit 21 and the second estimating unit 22 determine whether the rotation speed RM of the fan 8 is close to the design upper limit of the capacity (pressure loss) of the fan 8, and estimate the pressure loss based on the determination result.

[0028] [First estimation part] When the acquired rotation speed RM is equal to or less than a predetermined threshold value TP, the first estimation unit 21 estimates the pressure loss of the fan 8 based on this rotation speed RM.

[0029] FIG. 4 is a graph showing the relationship between the rotation speed of the fan 8 and pressure loss (hereinafter referred to as the "rotation speed-pressure loss curve"). In FIG. 4, the horizontal axis represents pressure loss (Pa) and the vertical axis represents the rotation speed (rpm) of the fan 8. The rotation speed-pressure loss curve can be obtained for each notch, and using this, the pressure loss occurring at that time can be estimated from the rotation speed of the fan 8. Note that FIG. 4 shows the rotation speed-pressure loss curve for the maximum notch NM. The rotation speed-pressure loss curve can be obtained, for example, by actually measuring multiple rotation speeds of the fan 8 and the corresponding pressure losses and obtaining a regression equation that approximately represents the distribution of these data. Note that if the manufacturer of the fan 8 publishes a rotation speed-pressure loss curve, this published curve may be used.

[0030] The first estimation unit 21 estimates the pressure loss PLM of the fan 8 at the maximum notch NM, for example, using the rotation speed-pressure loss curve shown in Fig. 4. For example, in a hypothetical case where the rotation speed RM is low, if the rotation speed RM acquired by the rotation speed acquisition unit 17 is, for example, 1000 rpm, the pressure loss PLM is estimated to be 96 Pa from the graph in Fig. 4 (see coordinate P1).

[0031] FIG. 5 shows a graph illustrating the relationship between the airflow rate of the fan 8 and pressure loss in the air conditioning system 1. In FIG. 5, the horizontal axis represents the airflow rate of the fan 8, and the vertical axis represents pressure loss. In FIG. 5, the graph Lim (shown by the bold line) represents the design upper limit of pressure loss at each airflow rate. If the measured pressure loss in the air conditioning system 1 exceeds the design upper limit, it is likely that some kind of malfunction has occurred, such as the system not being constructed as designed or an installed filter becoming clogged. In particular, it is important that the pressure loss of the air conditioning system 1 is below the design value when operating at the maximum notch NM.

[0032] When the rotation speed RM is sufficiently small, the pressure loss at the maximum notch NM falls far below the upper limit of the design, as shown in graph Gr1 (indicated by the dashed line) in Fig. 5. Therefore, in this case, no problem occurs even if the first estimating unit 21 estimates the pressure loss of the fan 8 using the rotation speed-pressure loss curve shown in Fig. 4.

[0033] However, as shown in graph Gr2 (shown by the two-dot chain line) in Fig. 5, when the pressure loss at the maximum notch NM is close to the design upper limit, estimating the pressure loss using the method of first estimator 21 may result in problems such as the estimated result being below the design upper limit even though the actual pressure loss exceeds the design upper limit due to the influence of variations in the rotation speed shown in Fig. 3. Furthermore, when the estimated result of pressure loss is close to the design upper limit, it is important to grasp as accurately as possible the extent of the difference between the estimated result and the upper limit.

[0034] [Second estimation part] In order to avoid the above-mentioned problems and to grasp the difference between the estimation result and the upper limit as accurately as possible, as shown in FIG. 2, when the acquired rotation speed RM is greater than the threshold value TP, the second estimation unit 22 estimates the pressure loss based on a first rotation speed R1, which is the rotation speed of the fan 8 operating at the first notch N1, and a second rotation speed R2, which is the rotation speed of the fan 8 operating at the second notch N2.

[0035] The second estimation unit 22 estimates the pressure loss using the following method. First, the second estimation unit 22 acquires the pressure loss corresponding to the first rotation speed R1 (hereinafter referred to as the "first pressure loss PL1") from the rotation speed-pressure loss curve for the first notch N1 (a curve similar to that in FIG. 4). The second estimation unit 22 also acquires the pressure loss corresponding to the second rotation speed R2 (hereinafter referred to as the "second pressure loss PL2") from the rotation speed-pressure loss curve for the second notch N2 (a curve similar to that in FIG. 4). This allows the pressure losses for the first notch N1 and the second notch N2 to be obtained.

[0036] Meanwhile, in equipment consisting of a fan and duct such as that of the present invention, it is known that the relationship between the fan's air volume Q and pressure loss P is expressed by the following formula (1). In formula (1), α is the air permeability, and n is the gap characteristic value. α and n are constants that are specific to the state of each installed equipment. These constants can be determined depending on the resistance of the duct, chamber, filter, etc., the installation state (duct length, bends, number of branches), etc. Q = α(P)1 / n…(1)

[0037] The second estimation unit 22 estimates the air volume (640 m) of the first notch N1. 3 / h) and first pressure loss PL1 and second notch air volume (480m 3 / h) and the second pressure loss PL2 are used as the air volume Q and the pressure loss P in the formula (1), and the air permeability α and the gap characteristic value n included in the above formula (1) are determined.

[0038] To determine the air permeability α and the gap characteristic value n in the above formula (1), first, take the logarithm of the air volume Q and pressure loss P in formula (1) to convert them into a linear formula in the following formula (2). y=ax+b…(2) where: a=1 / n b=logα

[0039] Let x1 be the logarithm of the airflow rate of the first notch N1, and y1 be the logarithm of the first pressure loss PL1 of the first notch N1. Furthermore, let x2 be the logarithm of the airflow rate of the second notch N2, and y2 be the logarithm of the second pressure loss PL2 of the second notch N2. From these two points (x1, y1) and (x2, y2), the variables a and b in the above equation (2) are determined. Here, since the variable a is equal to 1 / n, the gap characteristic value n in the above equation (1) can be determined from the determined variable a. Similarly, since the variable b is equal to logα, the air permeability α can be determined from the determined variable b.

[0040] In the second estimation unit 22, the air volume Q in the above formula (1) in which the air permeability α and the gap characteristic value n are specified is calculated based on the air volume at the maximum notch NM (800 m in this embodiment).3 / h). By substituting Λ / Λ, the pressure loss PLM at the maximum notch NM can be estimated. As described above, in the air conditioning system 1 of the present invention, in a state in which the accuracy of the estimation of the pressure loss PLM is likely to decrease (a state in which the rotation speed RM of the fan 8 is greater than the threshold value TP), the air permeability α and the gap characteristic value n in the above formula (1) are determined based on the first rotation speed R1 and the second rotation speed R2, rather than the rotation speed RM of the fan 8 at the maximum notch NM, which causes a decrease in accuracy, thereby estimating the pressure loss PLM with higher accuracy. Therefore, the air conditioning system 1 of the present invention can accurately estimate the pressure loss PLM from the rotation speed of the fan 8.

[0041] To further improve the accuracy, the second estimator 22 may estimate the pressure loss PLM based on the third rotation speed R3, which is the rotation speed of the fan 8 operating at the third notch N3, in addition to the first rotation speed R1 and the second rotation speed R2. That is, in addition to the data obtained at the first notch N1 and the second notch N2, data on the third rotation speed R3 and the corresponding pressure loss may also be added to determine the permeability α and the clearance characteristic value n in the above formula (1). In this case, the permeability α and the clearance characteristic value n may be determined, for example, based on the least squares method.

[0042] The threshold value TP can be determined appropriately from various perspectives. If the threshold value TP is too small, the second estimator 22 will perform the estimation even if the rotation speed RM of the fan 8 at the maximum notch NM is low, which will require a long time to estimate the pressure loss PLM. On the other hand, if the threshold value TP is too large, the accuracy of the estimation of the pressure loss PLM may decrease. For this reason, the threshold value TP is set, for example, by the following method. That is, the design upper limit PU of pressure loss at the maximum notch NM (shown in FIG. 5, 380 Pa in this example) is determined, and the rotation speed at coordinate P2 corresponding to the upper limit PU is determined from the rotation speed-pressure loss curve for the maximum notch NM shown in FIG. 4 as the upper limit RU of the rotation speed of the fan 8 (1760 rpm in this example). The threshold value TP is preferably determined based on this upper limit RU. In this embodiment, the threshold value TP is set, for example, to 0.85 to 0.95 times the upper limit RU of the rotation speed.

[0043] Fig. 6 is a flowchart showing the processing steps of the pressure loss estimation method performed by the air conditioning system 1 of this embodiment. As shown in Fig. 6, the pressure loss estimation method of the present invention includes an operation start step S1 of starting operation of the fan 8, a rotation speed acquisition step S2 of acquiring the rotation speed RM of the fan 8 operating at the maximum notch NM, a comparison step S3 of comparing the rotation speed RM with a predetermined threshold value TP, and an estimation step S4 of estimating the pressure loss of the fan based on the result of the comparison step S3.

[0044] In estimation step S4, if the rotation speed RM of the fan 8 operating at the maximum notch NM is equal to or less than a predetermined threshold value TP ("RM≦TP" in comparison step S3), the pressure loss PLM is estimated based on the rotation speed RM. On the other hand, if the rotation speed RM of the fan 8 operating at the maximum notch NM is greater than the threshold value TP ("RM>TP" in comparison step S3), the pressure loss PLM is estimated based on a first rotation speed R1, which is the rotation speed of the fan 8 operating at the first notch N1, and a second rotation speed R2, which is the rotation speed of the fan 8 operating at the second notch N2.

[0045] In the air conditioning system 1 of the present invention, the timing at which the first rotation speed R1 and the second rotation speed R2 are acquired is not particularly limited. FIG. 7 shows a flowchart specifying the timing at which the first rotation speed R1 and the second rotation speed R2 are acquired. In the embodiment shown in FIG. 7, a data preparation step Sa for acquiring the first rotation speed R1 and the second rotation speed R2 occurs before the rotation speed acquisition step S2 for acquiring the rotation speed RM of the fan 8 operating at the maximum notch NM. That is, the pressure loss estimation unit 16 of the air conditioning system 1 of this embodiment is configured to acquire the first rotation speed R1 and the second rotation speed R2 before acquiring the rotation speed RM during operation at the maximum notch NM. In this embodiment, the first rotation speed R1 and the second rotation speed R2 are acquired in advance as the rotation speed of the fan 8 increases, which prevents the program of the fan control unit 15 from becoming complicated.

[0046] FIG. 8 shows a flowchart of an embodiment different from that of FIG. 7. In the embodiment shown in FIG. 8, after a rotation speed acquisition step S2 for acquiring the rotation speed RM of the fan operating at the maximum notch NM, a data preparation step Sa for acquiring a first rotation speed R1 and a second rotation speed R2 is performed when the rotation speed RM is greater than a threshold value TP. That is, the pressure loss estimation unit 16 of the air conditioning system 1 of this embodiment is configured to acquire the first rotation speed R1 and the second rotation speed R2 when the rotation speed RM is greater than a predetermined threshold value TP. In this embodiment, because the first rotation speed R1 and the second rotation speed R2 are acquired only when necessary, the above estimation can be completed in a short time when the rotation speed RM is equal to or less than the threshold value TP.

[0047] As shown in Fig. 2, the air conditioning system 1 of this embodiment preferably further includes a display unit 23 that displays the estimated pressure loss PLM. The display unit 23 can be configured, for example, as a display (not shown) provided on the housing of the control unit 9 shown in Fig. 1. In addition, it is preferable that the air conditioning system 1 further includes a storage unit 24 that stores data of the estimated pressure loss PLM.

[0048] 6 to 8 include a display step S5 for displaying the estimated pressure loss PLM on the display unit 23 and a storage step S6 for storing the estimated pressure loss PLM. This allows the estimated pressure loss PLM to be effectively used to, for example, determine the installation status of the air conditioning system 1 or to determine whether a filter is clogged.

[0049] 1, when one air conditioning system 1 includes multiple fans 8, it is desirable to estimate the pressure loss described above for each fan. This allows the installation status of the air conditioning system 1 to be grasped more accurately.

[0050] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified and implemented in various ways.

[0051] [Note] The present invention includes the following aspects.

[0052] [Invention 1] An air conditioning system for air conditioning a room in a building, An air conditioner, a duct for transporting air conditioned by the air conditioner to the living room; a fan for pressure-feeding the air conditioned by the air conditioner to the living room through the duct; a fan control unit for controlling the operation of the fan; a pressure loss estimation unit that estimates a pressure loss of the fan, the fan control unit has a plurality of notches, and controls the rotation speed of the fan so that the air volume of the fan becomes a predetermined constant amount in each of the plurality of notches; the plurality of notches include a maximum notch at which the airflow rate of the fan is maximum, and first notches and second notches at which the airflow rate of the fan is smaller than the airflow rate of the maximum notch; The pressure loss estimation unit a rotation speed acquisition unit that acquires the rotation speed of the fan while it is operating at the maximum notch; a first estimation unit that estimates a pressure loss of the fan based on the rotation speed when the acquired rotation speed is equal to or less than a predetermined threshold; a second estimation unit that, when the acquired rotation speed is greater than the threshold value, estimates the pressure loss based on a first rotation speed that is the rotation speed of the fan operating at the first notch and a second rotation speed that is the rotation speed of the fan operating at the second notch. Air conditioning system. [Invention 2] 2. The air conditioning system according to claim 1, further comprising a display unit that displays the estimated pressure loss. [Invention 3] 3. The air conditioning system according to claim 1 or 2, further comprising a storage unit that stores data on the estimated pressure loss. [Invention 4] The air conditioning system according to any one of claims 1 to 3, wherein the pressure loss estimation unit is configured to acquire the first rotation speed and the second rotation speed before acquiring the rotation speed during operation at the maximum notch. [Invention 5] The air conditioning system according to any one of claims 1 to 3, wherein the pressure loss estimation unit is configured to acquire the first rotation speed and the second rotation speed when the rotation speed is greater than a predetermined threshold value. [Invention 6] the first notch is a notch set to an airflow rate that is one notch lower than the airflow rate set to the maximum notch, 6. The air conditioning system according to any one of claims 1 to 5, wherein the second notch is a notch set to an air volume that is one notch lower than the air volume set to the first notch. [Invention 7] 7. The air conditioning system according to any one of claims 1 to 6, wherein the rotation speed acquisition unit acquires the rotation speed after operation at the maximum notch has continued for a predetermined period of time. [Invention 8] A method for estimating pressure loss in an air conditioning system for air conditioning a room in a building, comprising: The air conditioning system includes: An air conditioner, a duct for transporting air conditioned by the air conditioner to the living room; a fan for pressure-feeding the air conditioned by the air conditioner to the living room through the duct; a fan control unit for controlling the operation of the fan; a pressure loss estimation unit that estimates a pressure loss of the fan, the fan control unit has a plurality of notches, and controls the rotation speed of the fan so that the air volume of the fan becomes a predetermined constant amount in each of the plurality of notches; the plurality of notches include a maximum notch at which the airflow rate of the fan is maximum, and first notches and second notches at which the airflow rate of the fan is smaller than the airflow rate of the maximum notch; The pressure loss estimation method includes: a rotation speed acquisition step of acquiring the rotation speed of the fan while it is operating at the maximum notch; a comparison step of comparing the rotation speed with a predetermined threshold value; an estimation step of estimating a pressure loss of the fan based on a result of the comparison step, In the estimation step, When the rotation speed of the fan operating at the maximum notch is equal to or less than a predetermined threshold, the pressure loss is estimated based on the rotation speed; When the rotation speed of the fan while operating at the maximum notch is greater than the threshold value, the pressure loss is estimated based on a first rotation speed that is the rotation speed of the fan while operating at the first notch and a second rotation speed that is the rotation speed of the fan while operating at the second notch. A method for estimating pressure loss in an air conditioning system. [Explanation of symbols]

[0053] 2. Building 5 Room 6. Air conditioner 7 Duct 8 Fans 15 Fan control unit 16 Pressure loss estimation section 17 Rotation speed acquisition section 21 1st estimation part 22 Second estimation part NM Maximum Notch N1 First notch N2 Second notch RM Fan speed when operating at maximum notch R1 First rotation speed R2 Second rotation speed TP Threshold

Claims

1. An air conditioning system for air conditioning a room in a building, An air conditioner, a duct for transporting air conditioned by the air conditioner to the living room; a fan for pressure-feeding the air conditioned by the air conditioner to the living room through the duct; a fan control unit for controlling the operation of the fan; a pressure loss estimation unit that estimates a pressure loss of the fan, the fan control unit has a plurality of notches, and controls the rotation speed of the fan so that the air volume of the fan becomes a predetermined constant amount in each of the plurality of notches; the plurality of notches include a maximum notch at which the airflow rate of the fan is maximum, and first notches and second notches at which the airflow rate of the fan is smaller than the airflow rate of the maximum notch; The pressure loss estimation unit a rotation speed acquisition unit that acquires the rotation speed of the fan while it is operating at the maximum notch; a first estimation unit that estimates a pressure loss of the fan based on the rotation speed when the acquired rotation speed is equal to or less than a predetermined threshold; a second estimation unit that, when the acquired rotation speed is greater than the threshold value, estimates the pressure loss based on a first rotation speed that is the rotation speed of the fan operating at the first notch and a second rotation speed that is the rotation speed of the fan operating at the second notch. Air conditioning system.

2. The air conditioning system according to claim 1 , further comprising a display unit that displays the estimated pressure loss.

3. The air conditioning system according to claim 2 , further comprising a storage unit that stores data of the estimated pressure loss.

4. 4. The air conditioning system according to claim 1, wherein the pressure loss estimation unit is configured to acquire the first rotation speed and the second rotation speed before acquiring the rotation speed during operation at the maximum notch.

5. 4. The air conditioning system according to claim 1, wherein the pressure loss estimation unit is configured to acquire the first rotation speed and the second rotation speed when the rotation speed is greater than a predetermined threshold value.

6. the first notch is a notch set to an air volume that is one notch lower than the air volume set to the maximum notch, 4. The air conditioning system according to claim 1, wherein the second notch is a notch set to an air volume that is one notch lower than the air volume set to the first notch.

7. The air conditioning system according to claim 1 , wherein the rotational speed acquisition unit acquires the rotational speed after operation at the maximum notch has continued for a predetermined period of time.

8. A method for estimating pressure loss in an air conditioning system for air conditioning a room in a building, comprising: The air conditioning system includes: An air conditioner, a duct for transporting air conditioned by the air conditioner to the living room; a fan for pressure-feeding the air conditioned by the air conditioner to the living room through the duct; a fan control unit for controlling the operation of the fan; a pressure loss estimation unit that estimates a pressure loss of the fan, the fan control unit has a plurality of notches, and controls the rotation speed of the fan so that the air volume of the fan becomes a predetermined constant amount in each of the plurality of notches; the plurality of notches include a maximum notch at which the airflow rate of the fan is maximum, and first notches and second notches at which the airflow rate of the fan is smaller than the airflow rate of the maximum notch; The pressure loss estimation method includes: a rotation speed acquisition step of acquiring the rotation speed of the fan while it is operating at the maximum notch; a comparison step of comparing the rotation speed with a predetermined threshold value; an estimation step of estimating a pressure loss of the fan based on a result of the comparison step, In the estimation step, When the rotation speed of the fan operating at the maximum notch is equal to or less than a predetermined threshold, the pressure loss is estimated based on the rotation speed; when the rotation speed of the fan while operating at the maximum notch is greater than the threshold value, estimating the pressure loss based on a first rotation speed that is the rotation speed of the fan while operating at the first notch and a second rotation speed that is the rotation speed of the fan while operating at the second notch; A method for estimating pressure loss in an air conditioning system.

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