JPH0510572B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diagnostic management method for air conditioning equipment that allows necessary maintenance information to be obtained quickly and accurately.

In recent years, the importance of air conditioning equipment has increased in the electronic equipment and pharmaceutical industries, and there is a strong demand for precision environmental control and reliability in preventing abnormal situations. For example, there are an increasing number of fields where failure of air conditioners cannot be tolerated, such as computer rooms, LSI manufacturing equipment, pharmaceutical manufacturing equipment, precision industry fields, and biological laboratories.

In order to deal with this, a centralized management system for air conditioning equipment has conventionally been normally provided. Typically, a central control room is provided within the building, where the electrical system equipment, crime prevention and disaster prevention equipment, water supply and drainage equipment, etc. in the building as well as air conditioners can be centrally managed. However, the mission of conventional centralized management systems for air conditioning equipment is to monitor and control air conditioning equipment based on input information from various sensors installed in equipment, and it is not possible to predict failures. Nakatsuta.

Therefore, if a failure occurs, we activate protection devices (backup air conditioners, etc.) and enter emergency operation to maintain the environment, and during that time, we investigate the cause of the failure and carry out repairs. Treatment is often required. However, such protection devices are usually inactive, and there are limitations in terms of their size and functionality, and new problems arise during long-term operation, so failures of the main device cannot be prevented. It would be better to prevent this from happening.

There are many conventional centralized control systems for air conditioners that output warning messages when an abnormal situation occurs, but most of these warning messages are used as commands for control operations.
It was not intended to diagnose the nature of the failure. Therefore,
In conventional systems, when an abnormality is recognized by an alarm, an air conditioning equipment engineer conducts an on-site inspection to determine the cause of the abnormality based on his experience and knowledge, and then decides whether maintenance work is necessary or not. Ta. Furthermore, although warning messages are used as reference during inspection work, identification of defective locations is still largely based on personal experience and knowledge. However, there are limits to the ability of such personal experience and knowledge to maintain equipment in good working order over a long period of time, and there are many equipment sites located in geographically distant locations where such failures cannot be tolerated. There are limits to their simultaneous management. Furthermore, the staff stationed in the central control room are rarely air conditioning engineers, and it is unreasonable to expect them to provide adequate maintenance information. For this reason, there has been a strong desire to develop a technology that can reliably predict failures of equipment in operation.

The present invention aims to provide a failure prediction technology for air conditioners that satisfies such requirements.
For this purpose, the present invention provides input information to a central monitoring system that monitors and controls air conditioning equipment based on input information from various sensor sections installed in equipment of air conditioning equipment. The present invention aims to provide a management system that is capable of diagnosing equipment by connecting an equipment diagnostic system that predicts failures in air conditioning equipment via a data bus line. Here, the equipment diagnosis system may be located inside the building where the central monitoring system is located, but it may also be located outside. The facility diagnosis system also includes accepting data from multiple central monitoring systems at various locations, and accepting data from these systems when multiple central monitoring systems exist within the same building.

According to the present invention, as this equipment diagnosis system, two aspects of the system, a system to be described in detail later as a "first diagnostic treatment method" and a system to be described in detail as a "second diagnostic treatment method", are used alone or in combination. and use it.

The former equipment diagnosis system (first diagnosis method)
In short, each detection signal from various sensors that detect the operating status of the air conditioner is input into a computer to monitor the operating status of the air conditioner, and at the same time, the detection signal is sent to the air blower while the air conditioner is operating. Select the current value and air volume, as well as the vibration and temperature of the blower motor, and obtain the correlation information between the correlation value of the blower current value and air volume and the cause of failure of the air conditioner, as well as the correlation value of the vibration and temperature of the blower motor. Correlation information between the defect cause items of the air conditioner is obtained in advance, and the detection signal of the blower current value and air volume, or the detection signal of the vibration and temperature of the blower motor reaches a value corresponding to the defect cause item. This system consists of a computer that outputs the items that cause the failure and predicts the location of the failure before the air conditioner breaks down.

The latter equipment diagnosis system (second diagnosis method)
In short, each detection signal from various sensors that detect the operating status of the air conditioner is input into a computer to monitor the operating status of the air conditioner, and at the same time, the detection signal is used to detect the compression during operation of the air conditioner. Select the machine current value and refrigerant pressure, obtain the correlation information between the correlation value of the compressor current value and refrigerant pressure, and the defect cause item of the air conditioner in advance, and generate the detection signal of the compressor current value and refrigerant pressure. When the value reaches the value corresponding to the defect cause item, a computer outputs the defect cause item, and the system predicts the defect location before the air conditioner breaks down.

The content of the present invention will be specifically explained below with reference to the drawings.

FIG. 1 shows a schematic system diagram of the management system of the present invention. As shown in the figure, signals detected by sensors in various facilities in the building are sent to the central monitoring system by the terminal transmission equipment, but at that time, these signals enter the data bus line and are transmitted from the data bus line to the central The central processing unit of the monitoring system picks up and receives these transmitted signals, and this central monitoring system takes on the task of monitoring and controlling various types of equipment as in the past. In the present invention, an equipment diagnosis system is connected to this data bus line. As detailed below, the equipment diagnosis system performs equipment diagnosis using a computer based on information input from the data bus line, and outputs the diagnosis results to a CRT (cathode ray tube), printer, or other magnetic recording medium. The most common form of this equipment diagnosis system is to install it at the equipment site and at a management company that handles maintenance work, and to connect the two with a line.

FIG. 2 is a flowchart illustrating how the functions of the management system of the present invention, such as abnormality prediction diagnosis, optimization control, and operation, are handled in the entire system.

The overall picture of the management system of the present invention is as shown in FIGS. 1 and 2, but the contents of the equipment diagnosis system, which is the gist of the system, will be explained in detail below using air conditioning in a computer room as an example. .

For example, in an air conditioning system in a computer room that is equipped with an air conditioner itself and a back-up air conditioner in the event of a failure, the main equipment is a device that operates continuously, so it is necessary to check for abnormalities and damage to each part in advance. It is necessary to predict and avoid situations that could lead to a shutdown. However, since unforeseeable and unavoidable emergencies are expected to occur, for such emergency situations, the state after the occurrence of the abnormality must be input (start/stop control).
By doing so, the transition will be made to backup startup. Taking this into consideration, this equipment diagnosis system outputs three types of messages: alarm messages, maintenance messages, and abnormality messages.

Alarm message (abnormality of each part leading to stoppage) These include, for example:

(a) Damage to the blower shaft (b) Breakage to the blower blades (c) Breakage to the blower bearing (d) Breakage to the blower belt (e) Burnout to the blower motor (f) Blower surging phenomenon When such a warning message is output An on-site inspection will be requested.

Maintenance messages (abnormalities that do not lead to shutdown) These include, for example, the following:

(a) Excessive air volume (improper damper adjustment, open inspection port) (b) Belt slip (c) Filter clogging (d) High free access resistance (e) Humidifier malfunction If a maintenance message like this is output, investigate. will be required.

Abnormal message (abnormality of unavoidable emergency stop) These include, for example:

(a) Power supply down (b) Control power supply down (c) Blower motor trips (d) Chilled water pipe damage or water leakage (e) Blower system damper or duct damage When such an abnormal message is output Automatic backup startup will be executed.

Next, it is also necessary to predict abnormalities in backup air conditioners. Backup models perform backup operation when the main unit stops abnormally or has reduced capacity.
Usually stopped. Therefore, equipment that is out of service for a long time has a high probability of failure and is difficult to manage. Therefore, it may be too late to diagnose the problem after it is actually in operation. For this reason, diagnose by performing rotational operation with the main body. In other words, in general, the protective device attached to the main unit predicts an abnormality in the parts that will lead to a shutdown and forcibly stops the system electrically. In many cases, it is unclear whether the protective device activated or not, and it is often difficult to analyze and investigate the cause. If backup operation is performed without investigating the cause of this problem, parts may be damaged or burnt out. Therefore, diagnosis should be made by rotating the main unit and backup operation as appropriate to ensure that the backup operation can be operated in the best possible condition. Prepare to become This backup diagnosis is classified into the following warning messages and maintenance messages.

Alarm message (activation of protective device) These include, for example:

(a) High pressure cut (b) Low pressure cut (c) Outdoor unit fan protection thermo (d) Indoor unit fan thermal (e) Compressor thermal (f) Compressor protection thermo If such a warning message is output, check the site. will be required.

Maintenance messages (causes for activating the protective device) These include, for example, the following:

(a) Abnormal outside temperature (b) Abnormal refrigerant amount (c) Defective expansion valve (d) Large indoor load (e) Abnormal air flow passing through the coil (f) Decreased outdoor performance (g) Abnormal bearing (h) Frost formation on the coil surface When such a maintenance message is output, an investigation is requested.

In order to actually diagnose an air conditioner (regardless of whether it is the main unit or backup type) as described above, detection signals from various sensors are input into the equipment diagnosis system, and a computer makes judgments about the equipment based on the input information. Then, these messages are categorized into the above-mentioned warning messages, maintenance messages, and abnormal messages and output.

A specific example of this diagnostic treatment will be explained below.

The first is to effectively use the correlation information between the current value of the blower motor and the airflow rate as input information for diagnosis.The second is to diagnose the relationship between the compressor current value and the refrigerant pressure. This is to use correlation information as input information and make a diagnosis based on this information.

[First diagnostic treatment]

First, the first diagnostic treatment method will be explained. this is,
When monitoring the operating status of an air conditioner by inputting each detection signal from various sensors that detect the operating status of the air conditioner into a computer, the current value of the blower motor while the air conditioner is operating is used as the detection signal. (hereinafter referred to as blower current value) and air volume,
Furthermore, the vibration and temperature of the blower motor are selected, and an alarm message, maintenance message, or abnormality message is selected and output from the correlation information between the blower current value and air volume, and the vibration or temperature information of the blower motor. That's true. This will be explained below with reference to FIGS. 3 to 6.

FIG. 3 shows the correlation between the blower current value and the air volume, which is used as a basis for detecting the causes of defects in various parts of the equipment from the operating state of the air conditioner. By monitoring the blower current value of an operating air conditioner as one input information and the air volume as the other input information, it is possible to classify the defective location based on the correlation between the two. For example, in some existing equipment, a band N (hatch area) of normal operation is determined as shown in Figure 3, but depending on the extent to which the correlation value of the two deviates from this band, If it shows a unique value, it is possible to classify where the cause of the defect exists.

More specifically, both the blower current value and the air volume are N.
If the drop is more than that, depending on the magnitude of the drop, A. Filter clogging, B. Belt slip, C. Large free access resistance, D. Surging phenomenon (varies), E. Belt breakage, etc. If the level becomes abnormally large, it is determined that there is an abnormality in the electrical system.

In addition, the blower current value increases from N, and the air volume decreases to N.
If the blower current value increases abnormally and the air volume decreases, depending on the degree, F bearing abnormality will be detected as the cause, and if the blower current value increases abnormally and the air volume decreases, the current value will be damaged or the bearing will be damaged. will be detected.

Further, when both the blower current value and the air volume become larger than N, information on excessive air volume is obtained.

The blower current value is taken from the ammeter and input into the computer. On the other hand, the air volume is output based on a relational expression determined from the characteristics of the current value of the blower and the air volume, and the above-mentioned judgment is made from the correlation between the air volume and the current value.

In Figure 4, a vibration sensor 2 and a surface temperature sensor 3 are attached to the bearing 1 of the blower motor, and a limit switch (not shown) is activated when the values detected by these sensors exceed a threshold value. , shows a state diagram in which the cause characteristic of a failure is identified by its ON-OFF signal. That is, when F, G, and H are determined from the monitoring of the blower current value and air volume shown in FIG. 3, motor abnormalities are classified and determined based on the ON-OFF signals shown in FIG. 4.

More specifically, if the limit switches of both the vibration sensor and the surface temperature sensor are ON, then the limit switch of the vibration sensor is ON.
So, the limit switch of the surface temperature sensor is
If it is OFF, there is an abnormality in the J dynamic balance, such as shaft eccentricity or blade damage.In addition, the limit switch of the vibration sensor is
If it is OFF and the limit switch of the surface temperature sensor is ON, determine whether the K bearing is lubricated or not.

All of the above output information is input to the computer, and the computer compares this monitor information with pre-registered stock information, selects an alarm message, maintenance message, or abnormality message, and sends an alarm buzzer, cathode ray tube, or even alarm message. Output to printer.

FIG. 5 shows an example of computer programming for implementing this first diagnostic procedure. A ₀ , AL, Amin, Amax in the flow of Figure 5 are the 6th
The values shown in the relationship diagram between air volume and blower current value are shown in the figure. Also, MD stands for a motor damper, and PAC stands for a package type air conditioner that is provided for backup in case of main unit failure.

As shown in the flowchart in Figure 5, various alarm messages (including abnormal messages) and maintenance messages can be selected and retrieved from the correlation information between the blower current value and air volume, as well as information about bearing vibration and temperature. Moreover, the location of the failure can also be displayed at this time. Therefore, according to this first diagnostic method, it becomes possible to perform a device diagnosis of a failure in an air conditioner reliably and easily, and to predict the failure and perform maintenance based on the prediction.
This means that it can be performed based on equipment judgment instead of conventional empirical rules.

[Second diagnostic treatment]

Next, the second diagnostic treatment method will be explained. When monitoring the operating status of an air conditioner by inputting each detection signal from various sensors that detect the operating status of the air conditioner into a computer, the compressor current during operation of the air conditioner is used as the detection signal. This is a method in which a value and refrigerant pressure are selected, and the correlation information between the compressor current value and refrigerant pressure is used to select and output an alarm message, maintenance message, or abnormal message. This will be explained with reference to FIGS.

FIG. 7 is a diagram showing the causal characteristics when the compressor current value and refrigerant pressure are input information. The compressor current value is detected by an ammeter, and the refrigerant pressure is detected by a pressure gauge, for example, the high pressure gas pressure on the compressor discharge side and the low pressure gas pressure on the evaporator outlet side, and these detection signals are detected while the air conditioner is operating. When monitored as input information, the cause of the failure can be identified as shown in FIG. In other words, in some existing equipment, a normal operation zone N (hatch area) is determined for both the high-pressure gas side and the low-pressure gas side, but the correlation value between the compressor current value and these refrigerant pressures is determined from this zone. The cause of the failure is classified according to the degree of deviation.

For example, in the correlation between the high-pressure gas side pressure of the refrigerant pressure and the compressor current value, if the compressor current value is detected to be higher than the normal value, depending on the tendency to increase, (b) Overfilling of refrigerant (c) Faulty expansion valve (d) Large indoor load (c) Large amount of air passing through the coil (decreased outdoor performance) Compressor bearing abnormality (compressor motor rare shot), etc. If the refrigerant pressure is lower than this and the compressor current value is abnormally high, it is determined that compressor bearing damage, fusible plug blowout, compressor motor burnout, etc. Of course, by the time such a situation occurs, the above judgment information will be obtained, so countermeasures will be taken before an accident occurs, and emergency protection devices will be activated automatically. You can also do that. Activation of such protection devices includes high pressure cut operation, compressor thermal activation,
Includes compressor protection thermostat. Note that the above information is not necessarily in this order, but it is used as a means of classification, and those that do not apply to this classification are removed, and the remaining information is determined to be the cause. be able to.

Then, in the correlation between the low-pressure gas side pressure of the refrigerant pressure and the compressor current value, if the compressor current value is detected to be lower than the normal value, the outside air temperature will decrease depending on the degree of the decrease. Insufficient refrigerant Defective expansion valve Reduced indoor load Reduced air flow passing through the coil If it is determined that there is frost on the coil surface, and the compressor current value drops abnormally, it may be due to freezing on the coil, backing of the refrigerant, or valve. This may lead to accidents such as cracking, motor burnout, etc. However, before such an accident occurs,
A low-pressure cut operation will be performed, and appropriate action will be taken from the information obtained along the way.

In this way, it is possible to identify the cause of equipment failure from the correlation information between compressor current value and refrigerant pressure. By detecting the temperature (referred to as temperature) and the current value of the blower motor (referred to as compressor current value), it is possible to determine the cause characteristic by selective judgment.

FIG. 8 shows an example of selection judgment similar to the above, and shows the causal characteristics depending on the suction air temperature and refrigerant pressure.
FIG. 8a shows the refrigerant overfilling characteristic in which an abnormality in the expansion valve is determined from information on the suction air temperature when refrigerant overfilling is determined in FIG. 7b.
That is, in the correlation between the intake air temperature and the high-pressure gas side pressure, an expansion valve abnormality is determined when the high-pressure gas side pressure is lower than the region of the normal operating characteristic N'. FIG. 8b shows the refrigerant shortage characteristic in which an abnormality in the expansion valve is determined from information on the suction air temperature when the refrigerant shortage is determined in FIG.
That is, in the correlation between the intake air temperature and the low-pressure gas side pressure, an expansion valve abnormality is determined when the low-pressure gas side pressure increases from the region of the normal operating characteristic N'.

Figure 9a shows that the increase in air flow passing through the coil (E) and the decrease in air flow passing through the coil (W) determined in Figure 7 are determined based on the input information of the indoor blower current value of the air conditioner, and this blower current value is used for normal operation. If the blower current value falls below the range N', it is determined whether the blower current has froze or not, depending on the degree of the drop.
If the increase exceeds N', determine whether there is a lack of filter, insufficient bearing lubrication, or poor shaft balance depending on the degree of increase.

Fig. 9b shows that the outdoor functional capacity decrease determined in Fig. 7 is determined from the input information of the outdoor blower current value of the air conditioner when this blower current value is within the normal operating range.
If the blower current value decreases below N′, it is determined that the rough-in clogging is occurring and the shaft is idling according to the degree of this decrease.
If the increase is greater than N', determine whether the bearing is abnormal (non-lubricated type) due to foreign matter or failure depending on the degree of increase.

All determinations of cause characteristics based on such input signals can be performed by a computer. The computer determines the cause of the failure based on each input signal,
Select and output alarm messages, maintenance messages, or abnormal messages to a cathode ray tube, printer, or alarm buzzer.

Figures 10a-d show examples of computer programming for this second diagnostic procedure. Further, e in FIG. 10 shows a flow for outputting a warning message when various protection devices are activated.

In this way, it is possible to diagnose the causes of failures in various parts of the air conditioner based on the correlation information between the compressor current value and refrigerant pressure. By analyzing the input, more accurate failure prediction diagnosis can be made.

The first and second diagnostic methods described above may be performed independently of each other, but by implementing both in combination, even more accurate diagnosis can be achieved.

The equipment diagnosis technology of the present invention has a feature that conventional management systems do not have, especially in that maintenance messages can be obtained, and by utilizing these maintenance messages, it is possible to detect malfunctions or breakdowns in air conditioning equipment in areas where defects or breakdowns are unacceptable. It becomes possible to ensure complete maintenance management. In other words, in the past, objective information similar to such maintenance messages could not be obtained, and diagnosis always depended on personal experience and knowledge ability, so depending on the timing and opportunity of diagnosis, it may be too late. The present invention can greatly improve the problem that it has been difficult to ensure the completeness of the product due to excessive labor required for inspection and repair. It is possible to quickly and accurately judge the situation and take measures to maintain the system at all times, and it is also possible to prevent accidents that may lead to breakdowns, thereby effectively achieving the purpose stated at the beginning.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an overall example of the building management system of the present invention, FIG. 2 is a system diagram showing an example of the relationship between diagnosis, control, and operation of the building management system of the present invention, and FIG. Figure 4 is an explanatory diagram for determining the cause of failure from the vibration and temperature of the motor. Figure 5 is a diagram for determining the cause of failure from the blower current value and air volume. A flowchart showing an example of computer programming. Fig. 6 is a relationship diagram between blower current value and air volume to explain the signal values in Fig. 5. Fig. 7 shows the cause of failure based on compressor current value and refrigerant pressure. Figure 8 is a cause characteristic diagram for making a judgment, Figure 8 is a cause characteristic diagram based on refrigerant pressure and suction air temperature, Figure 9 is a cause characteristic diagram based on blower current value, and Figures 10 a to e are for carrying out diagnosis according to the present invention. 1 is a flow diagram illustrating an example of a computer program. 1...Bearing, 2...Vibration sensor, 3...Surface temperature sensor.

Claims (1)

[Claims] 1. A central monitoring system that monitors and controls air conditioning equipment based on input information from various sensor units installed in the equipment of air conditioning equipment, based on the input information. A method of diagnosing and managing air conditioning equipment by connecting an equipment diagnosis system that predicts failures in air conditioning equipment via a data bus line, the method comprising: diagnosing air conditioning equipment using the equipment diagnosis system; Each detection signal from various sensors that detect the operating status of the air conditioner is input to the computer to monitor the operating status of the air conditioner. In addition, the vibration and temperature of the blower motor are selected, and the correlation information between the correlation value of the blower current value and air volume and the cause of the defect in the air conditioner, as well as the correlation value between the vibration and temperature of the blower motor and the defect in the air conditioner. Correlation information between the cause items is obtained in advance, and when the detection signal of the blower current value and air volume, or the vibration and temperature detection signal of the blower motor reaches a value corresponding to the cause item, the cause of the failure is determined. A method for diagnosing and managing air conditioning equipment, characterized in that a computer outputs items and predicts a defective part of the air conditioning equipment before it breaks down. 2. The central monitoring system, which monitors and controls air conditioning equipment based on input information from various sensors installed in equipment of air conditioning equipment, uses the above input information to detect malfunctions in air conditioning equipment. A method of managing air conditioning equipment while diagnosing it by connecting an equipment diagnosis system that makes predictions with a data bus line, the method of managing the air conditioning equipment while diagnosing the air conditioning equipment using the equipment diagnosis system. The operating status of the air conditioner is monitored by inputting each detection signal from various sensors that detect Correlation information between the correlation value of the machine current value and refrigerant pressure and the defect cause item of the air conditioner is obtained in advance, and the detection signal of the compressor current value and refrigerant pressure reaches the value corresponding to the defect cause item. A method for diagnosing and managing air conditioning equipment, characterized in that when a fault occurs, a computer outputs the cause of the fault, thereby predicting the location of the fault before the air conditioning equipment breaks down.