JP7404937B2 - air supply system - Google Patents

Description

The present invention relates to an air supply system.

Conventionally, rooms such as stores, for example, are provided with air supply systems. The air supply system includes an air supply fan and a differential pressure detection sensor. The air supply fan supplies external air to the inside of the store. The differential pressure detection sensor detects the differential pressure between the inside and outside of the store.

In such an air supply system, the pressure inside the store is equal to the pressure outside the store (atmospheric pressure), or the pressure inside the store is equal to the pressure outside the store, depending on the detection result of the differential pressure detection sensor. (For example, see Patent Document 1) by driving an air supply fan so that the pressure becomes higher than the atmospheric pressure (atmospheric pressure).

Japanese Patent Application Publication No. 2001-153441

By the way, in the above-mentioned air supply system, the air supply fan and the differential pressure detection sensor, which are the constituent elements, are mainly arranged in the attic of the store. The duct in which the differential pressure detection sensor is installed is installed in the attic of the store in a manner that communicates the inside and outside of the store, but if the duct is damaged, it should be checked visually. It is difficult. Therefore, even if the duct is damaged and the detection result by the differential pressure detection sensor is different from the original differential pressure inside and outside the store, it cannot be detected unless the differential pressure detection sensor is malfunctioning.

The above air supply system relies on the detection accuracy of the differential pressure sensor, and as described above, even if the duct or the like is damaged, the air supply fan is driven based on the detection result of the differential pressure sensor. Driving the air supply fan in this way not only causes the air supply fan to be driven unnecessarily, leading to an increase in power consumption, but also poses a risk of not being able to achieve positive pressure in the store. Yes, not desirable.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to provide an air supply system that can satisfactorily diagnose whether or not there is a failure in an element that detects the differential pressure between the inside and outside of a target room.

In order to achieve the above object, the air supply system according to the present invention provides an air supply system for controlling the inside of the target room based on the differential pressure detected by the differential pressure detection sensor that detects the differential pressure between the inside and outside of the target room. An air supply system comprising a control unit that performs normal operation to drive an air supply fan that supplies external air, wherein the control unit operates the air supply fan when a condition for starting a failure diagnosis operation is satisfied. After the first differential pressure is detected by the differential pressure detection sensor while being driven at one of the maximum frequency and minimum frequency of the allowable range for a predetermined time, the air supply fan is operated at the other of the maximum frequency and the minimum frequency of the allowable operating range. A second differential pressure is detected by the differential pressure detection sensor while driving for a predetermined period of time, and whether the absolute value of the difference between the first differential pressure and the second differential pressure is greater than or equal to a preset value. The control unit performs a failure diagnosis operation to determine whether the failure diagnosis operation is such that the number of consecutive times the absolute value is determined to be less than the set value is equal to or greater than a predetermined reference number of times in the failure diagnosis operation. In this case, the system is characterized in that the notification section is caused to perform a notification operation.

Further, the air supply system according to the present invention provides an air supply system that supplies external air to the inside of the target room based on a differential pressure detected by a differential pressure detection sensor that detects a differential pressure between the inside and outside of the target room. The air supply system includes a control unit that performs normal operation to drive an air fan, and the control unit controls the air supply fan to a maximum frequency within an allowable operating range and a After the first differential pressure is detected by the differential pressure detection sensor while driving at one of the minimum frequencies for a predetermined time, the air supply fan is driven for a predetermined time at the other of the maximum frequency and the minimum frequency of the allowable operation range. A second differential pressure is detected by the differential pressure detection sensor, and the immediate difference detected by the differential pressure detection sensor immediately before the supply air fan is driven for a predetermined period of time at one of the maximum frequency and minimum frequency of the permissible operating range. At least one of a first absolute value of the difference between the pressure and the first differential pressure and a second absolute value of the difference between the first differential pressure and the second differential pressure is set in advance. The controller performs a fault diagnosis operation to determine whether the first absolute value and the second absolute value are less than the set value in the fault diagnosis operation. If the number of consecutive times it is determined that this is the case is greater than or equal to a predetermined reference number, the notification unit is caused to perform a notification operation.

Further, in the air supply system of the present invention, the control unit controls the air supply fan at a predetermined frequency when the air supply fan is stopped at the time when the start condition for the failure diagnosis operation is satisfied. It is characterized by being driven for a predetermined period of time.

According to the present invention, when the control unit satisfies the start condition for the failure diagnosis operation, the control unit drives the air supply fan at one of the maximum frequency and the minimum frequency within the allowable operating range for a predetermined period of time, and uses the differential pressure detection sensor to operate the first air supply fan. After detecting the differential pressure of The control unit performs a fault diagnosis operation to determine whether the absolute value of the difference with the second differential pressure is equal to or greater than a preset value, and in the fault diagnosis operation, the control unit determines whether the absolute value If the number of consecutive judgments that the value is less than the value is equal to or greater than a predetermined reference number, the alarm unit will perform an alarm operation, so the absolute value of the difference in differential pressure when a pressure difference is forcibly created. This has the effect that it is possible to effectively diagnose whether or not there is a failure in the element that detects the differential pressure between the inside and outside of the target chamber.

Further, according to the present invention, when the control unit satisfies the starting conditions for the failure diagnosis operation, the control unit operates the air supply fan at one of the maximum frequency and minimum frequency within the allowable operating range for a predetermined period of time, and uses the differential pressure detection sensor to operate the air supply fan. After detecting the first differential pressure, the second differential pressure is detected by the differential pressure detection sensor while driving the air supply fan at the other of the maximum frequency and the minimum frequency within the allowable operating range for a predetermined period of time, and the air supply fan is operated. A first absolute value of the difference between the immediately preceding differential pressure detected by the differential pressure detection sensor and the first differential pressure immediately before driving for a predetermined time at one of the maximum frequency and the minimum frequency of the allowable range, and the first differential pressure. and a second absolute value of the difference between the differential pressure and the second differential pressure. In the diagnostic operation, if the number of consecutive times it is determined that the first absolute value and the second absolute value are less than the set value is equal to or greater than a predetermined reference number, the notification unit is caused to perform an notification operation. , it is possible to use the absolute value of the differential pressure difference when a pressure difference is forcibly created, and it is possible to effectively diagnose whether there is a failure in the element that detects the differential pressure between the inside and outside of the target room. It has the effect of being able to do it.

FIG. 1 is a schematic diagram schematically showing an air supply system according to an embodiment of the present invention. FIG. 2 is a block diagram schematically showing a characteristic control system of the air supply system according to the embodiment of the present invention. FIG. 3 is a flowchart showing the processing contents of the fault diagnosis operation performed by the fault diagnosis operation control processing section of the control section shown in FIG. FIG. 4 is a flowchart showing the contents of the differential pressure determination process shown in FIG. 3. FIG. 5 is a flowchart showing processing contents of a modification of the differential pressure determination processing shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an air supply system according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram schematically showing an air supply system according to an embodiment of the present invention, and FIG. 2 schematically shows a characteristic control system of the air supply system according to an embodiment of the present invention. FIG. In the air supply system illustrated here, the target room is, for example, a store 1 such as a convenience store or a supermarket. The store 1 is provided with an air conditioner 10 and exhaust devices 20a and 20b.

The air conditioner 10 adjusts the temperature, humidity, cleanliness, etc. of the air inside the store 1 (hereinafter also referred to as the store) (hereinafter also referred to as internal air) and maintains it in a comfortable condition. It is equipped with The indoor unit 11 is installed on the ceiling or the like inside the store, and is connected through a refrigerant pipe 13 to an outdoor unit 12 installed outside the store 1 (hereinafter also referred to as outside the store). In such an air conditioner 10, the refrigerant circulates between the indoor unit 11 and the outdoor unit 12 while repeating compression, condensation, adiabatic expansion, and evaporation, thereby adjusting the temperature of the internal air. Note that here, the air conditioner 10 cools internal air, and the indoor unit 11 is provided with a plurality of (for example, four) air outlets 11a.

Although not shown in the drawing, the store 1 has an entrance/exit for customers etc. formed in a part of the outer wall 2, and inside the store there is a cooking area where food is prepared, a showcase etc. A product storage device is installed.

A plurality of exhaust devices 20a and 20b (two in the illustrated example) are provided, and exhaust flow paths 21a and 21b are provided at locations separated from each other. The exhaust channels 21a and 21b are provided in the attic so as to communicate between the inside of the store and the outside of the store, and exhaust fans 22a and 22b are disposed in the middle thereof. The exhaust fans 22a and 22b are driven by operating an operating section (not shown) installed in the store 1 for the purpose of ventilating the store 1 and discharging odors and the like. When the exhaust fans 22a, 22b are driven, such exhaust devices 20a, 20b introduce internal air from the inlets 23a, 23b of the exhaust channels 21a, 21b, and allow the air to pass through the exhaust channels 21a, 21b. It is then discharged outside the store.

Although the exhaust devices 20a and 20b have been described as having exhaust channels 21a and 21b that communicate the inside of the store and the outside of the store, the exhaust devices 20a and 20b are formed on the outer wall 2 of the store (target room) 1. An exhaust fan called a ventilation fan may be installed in the exhaust hole. In this case, the opening of the exhaust hole that faces the interior of the store serves as an inlet, and by driving the exhaust fan, internal air is introduced through the inlet and exhausted outside the store.

The air supply system includes a differential pressure detection device 30, an air supply device 40, and a control section 50. The differential pressure detection device 30 includes a differential pressure detection duct 31 and a differential pressure detection sensor 32.

The differential pressure detection duct 31 is installed in the attic so as to communicate between the inside of the store and the outside of the store. The differential pressure detection duct 31 has an opening 33 at one end facing into the store, and an opening 34 at the other end facing outside the store. The differential pressure detection duct 31 allows air to flow along its axial direction.

The differential pressure detection sensor 32 is disposed at an arbitrary location in the differential pressure detection duct 31, and detects the differential pressure between the inside of the store and the outside of the store. This differential pressure detection sensor 32 provides the detection result to the control unit 50 as a differential pressure signal.

The air supply device 40 includes an air supply flow path 41. The air supply channel 41 is provided in the attic in a manner that communicates the inside of the store with the outside of the store, and one end faces the outside of the store and is provided with an outside air introduction port 42. The other end faces into the store and is provided with air supply ports 43a and 43b. Further, in the air supply flow path 41, an air supply fan 44 is disposed between the outside air introduction port 42 and the branch point. The air supply fan 44 is driven according to a command given from the control section 50. Further, an air supply fan detection sensor 44a is provided near the air supply fan 44. The air supply fan detection sensor 44a detects whether or not the air supply fan 44 is being driven, and provides the detection result to the control unit 50 as a detection signal.

Such an air supply device 40 introduces external air from an outside air introduction port 42 when the air supply fan 44 is driven, and blows it into the store from air supply ports 43a and 43b after passing through the air supply flow path 41. It is something. In the air supply device 40, the air supply ports 43a and 43b are arranged near the inlet ports 23a and 23b of the exhaust devices 20a and 20b.

More specifically, the air supply port 43a is arranged closer to the inlet 23a than the air outlet 11a of the air conditioner 10, and the air supply port 43b is arranged closer to the air outlet 11a of the air conditioner 10. is also arranged in a manner close to the introduction port 23b.

The control unit 50 centrally controls the operation of each part of the air supply system according to programs and data stored in the storage unit 55, and includes a normal operation control processing unit 51 and a failure diagnosis operation control processing unit 52. ing.

The normal operation control processing unit 51 uses the differential pressure signal given from the differential pressure detection sensor 32 to make the pressure inside the store equal to the pressure outside the store (atmospheric pressure), or to make the pressure inside the store higher than the pressure outside the store. Normal operation is performed in which the air supply fan 44 is driven so that the air supply fan 44 becomes larger.

The failure diagnosis operation control processing unit 52 determines through a clock unit (not shown) that a preset start time (for example, around 1:00) has passed while a predetermined interval time (for example, about 48 hours) has passed. In this case, the failure diagnosis operation described below is performed assuming that the start conditions for the failure diagnosis operation are satisfied, and the input processing section 521, the fan drive processing section 522, the first judgment processing section 523, the second judgment processing section 524, and the output A processing section 525 is provided.

The input processing section 521 inputs the differential pressure signal from the differential pressure detection sensor 32 and the detection signal from the air supply fan detection sensor 44a.

The fan drive processing section 522 sends a drive command at an arbitrary frequency to the air supply fan 44 to drive the air supply fan 44 at the frequency.

The first determination processing section 523 calculates the absolute value of the difference in differential pressure from each differential pressure input through the input processing section 521, and calculates the absolute value of the difference in differential pressure in the differential pressure determination process in the failure diagnosis operation, although the details will be described later. It is determined whether or not there is a setting value (for example, 1 Pa) included in the setting value information read out from the storage unit 55, and if there is a setting value or more, it is determined as "OK". If there is no value equal to or greater than the set value, it is determined as "NG".

When the differential pressure determination process through the first determination processing unit 523 is determined to be “NG”, the second determination processing unit 524 counts the number of consecutive determinations as “NG”, and calculates the number of consecutive counts. It is determined whether or not the number of times is equal to or greater than the reference number of times (for example, four times) included in the reference number of times information read from the storage unit 55.

The output processing section 525 outputs a notification command to the notification section 60. Here, the notification section 60 performs a notification operation based on the notification command output from the output processing section 525. In the present embodiment, the notification section 60 is constituted by a display section that displays various information constituting the management device of the store 1, for example. The notification operation performed by the notification section 60 is to display a warning on the display section.

Note that the control unit 50 may be realized by, for example, causing a processing device such as a CPU (Central Processing Unit) to execute a program, that is, by software, or may be realized by hardware such as an IC (Integrated Circuit). Alternatively, it may be realized using a combination of software and hardware.

In the air supply system having the above configuration, under the condition that the exhaust devices 20a and 20b are operating, the normal operation control processing section 51 of the control section 50 detects the difference given from the differential pressure detection sensor 32. The pressure signal drives the air supply fan 44 so that the pressure inside the store is equal to the pressure outside the store (atmospheric pressure), or the pressure inside the store is greater than the pressure outside the store. The external air outside the store introduced through 42 passes through the air supply flow path 41 and is blown into the store through the air supply ports 43a and 43b.

The air supply port 43a is arranged closer to the inlet 23a than the air outlet 11a of the air conditioner 10, and the air inlet 43b is arranged closer to the inlet than the air outlet 11a of the air conditioner 10. 23b, most of the external air blown out from the air supply port 43a is introduced into the exhaust flow path 21a through the inlet 23a without circulating inside the store, and is discharged outside the store. Most of the external air discharged through the air supply port 43b and blown out from the air supply port 43b is introduced into the exhaust flow path 21b through the inlet port 23b without circulating inside the store, and is discharged outside the store.

That is, the amount of air blown into the store through the air supply device 40 and circulated within the store can be reduced, and the amount of outside air entering the store can be reduced.

The control unit 50 that is performing such normal operation sends a message through the clock unit that if the preset start time has elapsed while the predetermined interval time has elapsed, it assumes that the start conditions for the failure diagnosis operation are satisfied and starts the next operation. Carry out troubleshooting operations such as:

FIG. 3 is a flowchart showing the processing contents of the fault diagnosis operation performed by the fault diagnosis operation control processing section 52 of the control section 50 shown in FIG.

In this failure diagnosis operation, the failure diagnosis operation control processing section 52 determines whether or not the air supply fan 44 is being driven by inputting the detection signal from the air supply fan detection sensor 44a through the input processing section 521. (Step S101).

If the air supply fan 44 is not driving (step S101: No), that is, if the air supply fan 44 has stopped driving due to some factor, the failure diagnosis operation control processing unit 52 controls the air supply through the fan drive processing unit 522. A drive command is sent to the fan 44 at the rated frequency (for example, about 40 Hz) to drive the air supply fan 44 at the rated frequency (step S102), and the air supply fan 44 is driven for a predetermined period of time (for example, about 30 minutes to 60 minutes). The process waits for the elapsed time (step S103). If the predetermined time has elapsed (step S103: Yes), the failure diagnosis operation control processing unit 52 performs differential pressure determination processing (step S104).

On the other hand, if the air supply fan 44 is being driven in step S101 (step S101: Yes), the failure diagnosis operation control processing unit 52 performs differential pressure determination processing (step S104).

FIG. 4 is a flowchart showing the contents of the differential pressure determination process shown in FIG. 3. The failure diagnosis operation control processing unit 52 of this differential pressure determination process determines whether or not a differential pressure signal is input from the differential pressure detection sensor 32 through the input processing unit 521, that is, the differential pressure (immediate differential pressure) detected by the differential pressure detection sensor 32 is detected. It is determined whether or not it has been detected (step S104A).

If it is determined that the immediately preceding differential pressure has not been detected by the differential pressure detection sensor 32 (step S104A: No), the failure diagnosis operation control processing unit 52 repeats this process. On the other hand, when the immediately preceding differential pressure is detected by the differential pressure detection sensor 32 (step S104A: Yes), that is, when the differential pressure signal from the differential pressure detection sensor 32 is input through the input processing section 521, the failure diagnosis operation control processing section 52 sends a drive command at the maximum frequency (for example, about 60 Hz) within the allowable operating range to the air supply fan 44 through the fan drive processing unit 522 to drive the air supply fan 44 at the maximum frequency (step S104B); Waiting for input of a differential pressure signal from the differential pressure detection sensor 32 through the input processing unit 521 until a preset time (for example, about 10 to 15 minutes) has elapsed after starting the process of step S104B; That is, the process waits for the differential pressure (first differential pressure) to be detected by the differential pressure detection sensor 32 (step S104C, step S104D).

If the first differential pressure is detected and the set time has elapsed (step S104C: Yes, step S104D: Yes), the failure diagnosis operation control processing section 52 allows the air supply fan 44 to operate through the fan drive processing section 522. Sends a drive command at the minimum frequency of the range (for example, about 15 Hz) to drive the air supply fan 44 at the minimum frequency (step S104E), and waits for a preset time after starting the process of step S104E. (for example, about 10 to 15 minutes), the input processing unit 521 waits for the input of the differential pressure signal from the differential pressure detection sensor 32, that is, the differential pressure (second differential pressure) by the differential pressure detection sensor 32. Waits for detection (step S104F, step S104G).

If the second differential pressure is detected and the set time has elapsed (step S104F: Yes, step S104G: Yes), the failure diagnosis operation control processing section 52 determines the immediately preceding differential pressure and the second differential pressure through the first determination processing section 523. The absolute value of the difference from the first differential pressure (first absolute value) and the absolute value of the difference between the first differential pressure and the second differential pressure (second absolute value) are calculated (step S104H ).

The failure diagnosis operation control processing unit 52 that has calculated the first absolute value and the second absolute value reads the setting value information from the storage unit 55 through the first determination processing unit 523, and calculates the first absolute value and the second absolute value. The set value (for example, 1 Pa) included in the set value information is compared, and the second absolute value and the set value are compared (step S104I).

As a result of the above step S104I, if at least one of the first absolute value and the second absolute value is greater than or equal to the set value (step S104J: Yes), that is, if only the first absolute value is greater than or equal to the set value, If only the second absolute value is greater than or equal to the set value, or if the first absolute value and the second absolute value are greater than or equal to the set value, the failure diagnosis operation control processing unit 52, through the first determination processing unit 523, OK'' and stored in the storage unit 55 (step S104K), and then the procedure is returned to end the current differential pressure determination process.

On the other hand, as a result of step S104I, if at least one of the first absolute value and the second absolute value is not equal to or greater than the set value (step S104J: No), that is, the first absolute value and the second absolute value are If it is less than the set value, the failure diagnosis operation control processing unit 52 makes a determination of “NG” through the first determination processing unit 523 and stores it in the storage unit 55 (step S104L), and then returns the procedure to the current one. The differential pressure determination process ends.

The failure diagnosis operation control processing unit 52 that has carried out the differential pressure determination process determines whether or not there is an “NG” determination in the differential pressure determination process through the second determination processing unit 524 (step S105), and determines “NG”. If there is no error (step S105: No), the procedure is returned to end the current failure diagnosis operation.

On the other hand, if there is an "NG" determination (step S105: Yes), the failure diagnosis operation control processing section 52 counts the number of consecutive "NG" determinations through the second determination processing section 524 (step S106). ” It is determined whether the number of consecutive determinations is equal to or greater than the reference number (for example, four times) included in the reference number of times information read from the storage unit 55 (step S107).

If the number of consecutive "NG" determinations is not equal to or greater than the reference number (step S107: No), the failure diagnosis operation control processing unit 52 returns the procedure and ends the current failure diagnosis operation.

On the other hand, if the number of consecutive "NG" determinations is equal to or greater than the reference number (step S107: Yes), the failure diagnosis driving control processing section 52 outputs a notification command to the notification section 60 through the output processing section 525 (step S107: Yes). S108). Thereby, the notification section 60 performs a notification operation such as displaying a warning on the display section. Thereafter, the failure diagnosis operation control processing unit 52 returns the procedure and ends the current failure diagnosis operation.

The control unit 50 that has performed such a failure diagnosis operation then drives the air supply fan 44 at the rated frequency for a predetermined period of time, and then performs the above-mentioned normal operation.

As explained above, according to the air supply system according to the embodiment of the present invention, the control unit 50 drives the air supply fan 44 at the maximum frequency for a set period of time when the start conditions for the failure diagnosis operation are satisfied. After the first differential pressure is detected by the differential pressure detection sensor 32, the second differential pressure is detected by the differential pressure detection sensor 32 while driving the air supply fan 44 at the minimum frequency for a set time, and the air supply fan 44 The first absolute value of the difference between the immediately preceding differential pressure and the first differential pressure detected by the differential pressure detection sensor 32 immediately before driving at the maximum frequency; and the first absolute value of the difference between the first differential pressure and the second differential pressure. A fault diagnosis operation is performed in which it is determined whether at least one of the second absolute value of the difference is greater than or equal to a set value. If the number of consecutive times it is determined that the absolute value of Absolute values can be used, and the presence or absence of a failure in the differential pressure detection device 30 that detects the differential pressure inside and outside the store 1 can be diagnosed favorably.

This prevents the air supply fan 44 from being driven unnecessarily and increasing power consumption, and also drives the air supply fan 44 so that the pressure inside the store 1 is greater than the pressure outside the store 1. This makes it possible to create positive pressure in the store 1.

According to the air supply system, if the air supply fan 44 has stopped driving at the time when the failure diagnosis operation start condition is satisfied, the control unit 50 drives the air supply fan 44 at the rated frequency for a predetermined period of time. , the differential pressure (immediate differential pressure) can be detected while the air supply fan 44 is being driven, thereby improving the accuracy of determining the presence or absence of a failure.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various changes can be made.

In the embodiment described above, the immediately preceding differential pressure was detected and the first absolute value and the second absolute value were calculated, but in the present invention, as shown in FIG. 5, the immediately preceding differential pressure is detected. The first differential pressure and the second differential pressure are detected to determine whether the absolute value of the difference between the first differential pressure and the second differential pressure is equal to or greater than a set value. You can also do this.

FIG. 5 is a flowchart showing processing contents of a modification of the differential pressure determination processing shown in FIG. 4. Note that the processes other than the differential pressure determination process (steps S101 to S103 and steps S105 to S108) in the failure diagnosis operation are the same as in the embodiment described above, so only the differential pressure determination process will be described here. .

The failure diagnosis operation control processing unit 52 for this differential pressure determination process sends a drive command at the maximum frequency (for example, about 60 Hz) within the allowable operating range to the air supply fan 44 through the fan drive processing unit 522, and the air supply fan 44 at the maximum frequency (step S104B), and by the time a preset time (for example, about 10 to 15 minutes) has elapsed after starting the process of step S104B, the differential pressure is increased through the input processing unit 521. The process waits for input of the differential pressure signal from the detection sensor 32, that is, waits for detection of the differential pressure (first differential pressure) by the differential pressure detection sensor 32 (step S104C, step S104D).

If the first differential pressure is detected and the set time has elapsed (step S104C: Yes, step S104D: Yes), the failure diagnosis operation control processing section 52 allows the air supply fan 44 to operate through the fan drive processing section 522. Sends a drive command at the minimum frequency of the range (for example, about 15 Hz) to drive the air supply fan 44 at the minimum frequency (step S104E), and waits for a preset time after starting the process of step S104E. (for example, about 10 to 15 minutes), the input processing unit 521 waits for the input of the differential pressure signal from the differential pressure detection sensor 32, that is, the differential pressure (second differential pressure) by the differential pressure detection sensor 32. Waits for detection (step S104F, step S104G).

If the second differential pressure is detected and the set time has elapsed (step S104F: Yes, step S104G: Yes), the failure diagnosis operation control processing section 52, through the first determination processing section 523, detects the first differential pressure. The absolute value of the difference between and the second differential pressure is calculated (step S104h).

The failure diagnosis operation control processing unit 52 that has calculated the absolute value reads the set value information from the storage unit 55 through the first determination processing unit 523, and compares the absolute value and the set value (for example, 1 Pa) (step S104I ).

As a result of step S104I, if the absolute value is equal to or greater than the set value (step S104j: Yes), the failure diagnosis operation control processing section 52 determines "OK" through the first determination processing section 523, and stores the information in the storage section 55. It is stored (step S104K), and then the procedure is returned to end the current differential pressure determination process.

On the other hand, as a result of the above step S104I, if the absolute value is not equal to or greater than the set value (step S104j: No), the failure diagnosis operation control processing section 52 determines "NG" through the first determination processing section 523 and stores it in the storage section 55. (step S104L), and then the procedure is returned to end the current differential pressure determination process.

By performing a failure diagnosis operation that includes such differential pressure determination processing, the absolute value of the differential pressure difference when a pressure difference is forcibly created can be used to detect the differential pressure inside and outside the store 1. The presence or absence of a failure in the differential pressure detection device 30 can be diagnosed successfully.

In the embodiments described above and the example shown in FIG. 5, the air supply fan 44 was driven at the maximum frequency and then at the minimum frequency, but in the present invention, the air supply fan 44 was driven at the minimum frequency. It may be possible to drive it at the maximum frequency later.

DESCRIPTION OF SYMBOLS 1... Store (target room), 10... Air conditioner, 20a, 20b... Exhaust device, 30... Differential pressure detection device, 31... Duct for differential pressure detection, 32... Differential pressure detection sensor, 40... Air supply device, 41... Air supply flow path, 42...Outside air introduction port, 43a, 43b...Air supply port, 44...Air supply fan, 44a...Air supply fan detection sensor, 50...Control unit, 51...Normal operation control processing unit, 52...Failure diagnosis operation Control processing section, 521... Input processing section, 522... Fan drive processing section, 523... First judgment processing section, 524... Second judgment processing section, 525... Output processing section, 55... Storage section, 60... Notification section.

Claims (3)

A control unit that performs normal operation to drive an air supply fan that supplies external air to the inside of the target room based on the differential pressure detected by a differential pressure detection sensor that detects the difference in pressure between the inside and outside of the target room. An air supply system comprising:
When the starting conditions for the failure diagnosis operation are satisfied, the control unit controls the differential pressure detection sensor to detect a first differential pressure while driving the air supply fan at one of a maximum frequency and a minimum frequency within an allowable operating range for a predetermined period of time. After detecting the second differential pressure, the differential pressure detection sensor detects a second differential pressure while driving the air supply fan at the other of the maximum frequency and the minimum frequency of the allowable operating range for a predetermined period of time; A fault diagnosis operation is performed to determine whether the absolute value of the difference with the second differential pressure is greater than or equal to a preset value,
The control unit may cause the notification unit to perform a notification operation if the number of consecutive times the absolute value is determined to be less than the set value is equal to or greater than a predetermined reference number in the failure diagnosis operation. Characteristic air supply system. A control unit that performs normal operation to drive an air supply fan that supplies external air to the inside of the target room based on the differential pressure detected by a differential pressure detection sensor that detects the difference in pressure between the inside and outside of the target room. An air supply system comprising:
When the starting conditions for the failure diagnosis operation are satisfied, the control unit controls the differential pressure detection sensor to detect a first differential pressure while driving the air supply fan at one of a maximum frequency and a minimum frequency within an allowable operating range for a predetermined period of time. After detecting the second differential pressure, the differential pressure detection sensor detects a second differential pressure while driving the air supply fan at the other of the maximum frequency and minimum frequency of the allowable operating range for a predetermined period of time, and the air supply fan is operated at the second differential pressure. a first absolute value of the difference between the immediately preceding differential pressure detected by the differential pressure detection sensor immediately before driving for a predetermined time at one of the maximum frequency and minimum frequency of the allowable operating range and the first differential pressure; A fault diagnosis operation is performed to determine whether at least one of the second absolute value of the difference between the first differential pressure and the second differential pressure is equal to or higher than a preset value,
In the failure diagnosis operation, the control unit determines that the number of consecutive times that the first absolute value and the second absolute value are less than the set value is equal to or greater than a predetermined reference number of times. An air supply system characterized by causing a notification unit to perform a notification operation. The control unit may drive the air supply fan at a predetermined frequency for a predetermined period of time if the air supply fan has stopped driving at the time when the start condition for the failure diagnosis operation is satisfied. The air supply system according to claim 1 or claim 2.

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