JPH0437339B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a failure diagnosis method for an air conditioner that prevents failures of the air conditioner by monitoring the operating status of the air conditioner.

For the management of air conditioning equipment in building management,
Various management techniques are required for temperature, humidity, dust, return air, disaster prevention, vibration, noise, airflow, corrosion, etc. Conventionally, management technology for such air conditioning equipment has largely depended on the personal experience, ability, and knowledge of maintenance personnel.As air conditioning equipment becomes more sophisticated and precision air conditioning control becomes more sophisticated, it has become increasingly difficult to manage it quickly and completely. has a limit. Especially in the management of buildings where precision air conditioning is required, such as computer rooms, semiconductor manufacturing equipment, pharmaceutical manufacturing equipment, etc., the importance of air conditioning equipment management is extremely high, and advanced management technology is required. Maintenance is an important issue, but there are problems in maintaining this through individual ability.

Generally, in normal building management, security equipment,
A control room is set up to centrally manage air conditioning equipment along with water supply and drainage equipment, electrical system equipment, disaster prevention equipment, etc., and in many cases, air conditioning equipment is also incorporated into the central management system. In such systems, the main focus is on automatic control of various devices, and the system is usually not intended to be used for detecting defective parts or predicting failures for maintenance purposes. Furthermore, it is rare for the personnel stationed in this central control room to be experts in air conditioning equipment, and therefore it is not possible to expect them to provide qualified maintenance information.

For these reasons, there is a strong desire to develop a failure prediction system for air conditioning equipment that cannot tolerate defects or failures.

The present invention has been made with the aim of satisfying this requirement. As a system that effectively achieves this objective, the present invention provides a system that monitors 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. As the detection signal of
Select the compressor current value and refrigerant pressure when the air conditioner is operating, and calculate 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. When the detection signals of the current value and refrigerant pressure reach values corresponding to the defect cause item, the computer outputs the defect cause item;
An object of the present invention is to provide a failure diagnosis method for an air conditioner that predicts a defective location before the air conditioner malfunctions.

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

FIG. 1 is a diagram showing the causal characteristics when the compressor current value and refrigerant pressure are used as input information. The compressor current value is detected with an ammeter, and the refrigerant pressure is detected with 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 in operation. When monitored as input information, the cause of the failure can be identified as shown in FIG. In other words, in some existing equipment, the normal operation band 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 within this band. The cause of the failure is classified according to the extent to which it deviates from the above.

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 (b) Large indoor load (c) Large air flow passing through the coil (decreased outdoor performance) Compressor bearing abnormality (c) Compressor motor rare shot, etc. can be determined. 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 1 to 1 is not necessarily in this order. There are the following causes of hot spots, and these can be used as a means of classification. In other words, it is possible to remove items that do not fall into this category and attribute the remaining items to the cause.

Similarly, 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, depending on the tendency to decrease, Insufficient refrigerant Defective expansion valve Indoor load reduction Reduced air flow passing through the coil If it is determined that there is frost on the coil surface, and the compressor current value decreases abnormally, it may be due to freezing of the coil, backing of the refrigerant, or This can lead to accidents such as valve cracks and motor burnouts. 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 the temperature) and the current value of the blower motor (referred to as the blower current value), it is possible to determine the causal characteristics by selectively determining the current value.

FIG. 2 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. 2a shows an example of the refrigerant overfilling characteristic for determining an expansion valve abnormality from information on the suction air temperature when refrigerant overfilling (b) in FIG. 1 is determined. 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. 2b shows an example of the refrigerant shortage characteristic in which an expansion valve abnormality 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 operation characteristic N'.

Fig. 3a 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 Fig. 1 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 is in the normal operating range.
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. 3b shows that the outdoor functional capacity decline determined in Fig. 1 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 falls below N', it is determined that the rough-in clogging is occurring and the shaft is idling according to the degree of the drop.
If the increase is greater than N', determine whether the bearing is abnormal (non-lubricated type) due to a foreign object, 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 4a-d show examples of this computer programming. Further, e in FIG. 4 shows a flow for outputting a warning message when various protection devices are activated.

In this way, the present invention diagnoses the causes of failures in various parts of the air conditioner based on the correlation information between the compressor current value and the refrigerant pressure, and the details of this correlation information are based on the intake air temperature and By analyzing the input of the blower current value, more accurate failure prediction and diagnosis can be performed. The results of such failure diagnosis can be judged by a computer and various warnings can be output, making conventional empirical maintenance work more reliable and improving the reliability of buildings where failures cannot be tolerated. The normal operation of the air conditioner can be guaranteed.

[Brief explanation of drawings]

Figure 1 is a failure cause characteristic diagram based on compressor current value and refrigerant pressure, Figure 2 is a failure cause characteristic diagram based on refrigerant pressure and suction air temperature, Figure 3 is a failure cause characteristic diagram based on blower current value, and Figure 4 a. -e are flow diagrams showing an example of a computer program used to implement the method of the present invention.

Claims (1)

[Claims] 1. 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 value while the air conditioner is in operation is used as the detection signal. and refrigerant pressure, and obtain correlation information in advance between the correlation value of the compressor current value and refrigerant pressure and the defect cause item of the air conditioner, and the detection signal of the compressor current value and refrigerant pressure is A failure diagnosis method for an air conditioner in which a computer outputs the cause of a failure when a value corresponding to the cause item is reached, and the failure location of the air conditioner is predicted before the air conditioner malfunctions.