KR100792714B1 - Method of rule-based fault detection and diagnosis in air-handling system with detailed classification - Google Patents

Abstract

A method of fault detection and diagnosis based on rules with detailed classification in an air handling system is provided to detect single fault for a predetermined component part in a short time for instant repair of the part, thereby minimizing the maintenance cost for a building and taking effective countermeasures for aged facilities. A method of fault detection and diagnosis based on rules with detailed classification in an air handling system includes the steps of assigning a predetermined coefficient as a threshold value required for fault diagnosis and collecting data values measured from component parts of the air handling system, and determining whether an outdoor air temperature factor is abnormal among the data values. If the outdoor air temperature is in a predetermined range, a mode corresponding to range is automatically selected. In the selected mode, a pre-assigned threshold value is read out to determine fault of a plurality of temperature factors according to a plurality of fault determining formulas assigned to the corresponding mode and to determine data on positive or negative direction of signals of the abnormal component part. If thermodynamic determination formulas for respective system parts are satisfied and the fault determination formulas including two or more of the temperature factors relating to each other are satisfied simultaneously, the temperature factors commonly included in the fault determination formulas are determined as fault factors.

Description

METHODS OF RULE-BASED FAULT DETECTION AND DIAGNOSIS IN AIR-HANDLING SYSTEM WITH DETAILED CLASSIFICATION}

1 is a view showing a relationship between a heating coil valve, a cooling coil valve and a mixed air damper for four operation modes in the conventional APAR method.

Figure 2 is a schematic diagram showing the configuration of the failure diagnosis and detection device of the classification rule-based method in the air conditioning system according to an embodiment of the present invention.

3 is a flowchart of a method of diagnosing and detecting a failure of a classification rule-based method in an air conditioning system according to an exemplary embodiment of the present invention.

4 is a detailed flowchart of a fixed diagnosis and detection method in Mode 1 of FIG. 3.

5 is a detailed flowchart of a fixed diagnosis and detection method in Mode 2 of FIG. 3.

FIG. 6 is a detailed flowchart of a fixed diagnosis and detection method in mode 3 of FIG. 3.

FIG. 7 is a flowchart of a fixed diagnosis and detection method in mode 4 of FIG. 3. FIG.

<Explanation of symbols for the main parts of the drawings>

110: first tachometer 120: second tachometer

130: first frequency meter 140: second frequency meter

210: first potentiometer 220: second potentiometer

230: third potentiometer 240: fourth potentiometer

310: outside temperature sensor 320: air supply temperature sensor

330: mixed air temperature sensor 340: circulating air temperature sensor

350: outside reference temperature sensor 400: central control unit

The present invention relates to a method and apparatus for detecting and diagnosing a failure of a detailed rule type rule-based method in an air conditioning system. More particularly, when any one of the components in the air conditioning system fails, A classification rule to locate and provide specific information on the positive or negative direction of the fault signal to prevent energy loss in the entire system due to degradation of the component in the shortest time. The present invention relates to a method and apparatus for detecting and diagnosing faults based on the method.

Recently, as buildings are getting higher and more intelligent, facility systems are more diversified and complex. As the building's heating, ventilation and air conditioning (HVAC) systems grow, automation, and complexity increase, the potential for economic loss and risk amplification in the event of failure increases. The impor- tant or poorly constructed building air conditioning systems can increase the energy consumption by 30-50% per year, indicating the importance of verification and performance diagnostic systems for energy installations.

Therefore, in order to secure trouble-free operation and diagnosis in various types of buildings, a distributed, automated verification and performance diagnosis system that can perform fault detection and diagnosis flexibly and effectively is required.

In particular, in energy facilities such as air conditioning facilities, the amount of energy that can be saved by the improvement of management technology is not negligible and can be increased by more than 20 ~ 30% after improving the failure condition by re-supervision of the air conditioning facilities of commercial buildings. Therefore, the importance of the fault detection and diagnosis system can be seen from this.

In order to achieve energy saving by optimal operation of the building, it is possible to predict or detect the gradual deterioration of the system according to the failure or aging, which is caused by the optimal control of the building equipment and the performance of the facility, and to quickly or in advance when the failure occurs. It must be dealt with. In addition, the performance degradation should be prevented, and the safety of the system should be secured to prevent inefficient waste of energy and deterioration of the indoor environment. Therefore, in order to maximize the effect of energy saving, pleasant indoor environment preservation, and maintenance cost reduction, it is necessary to develop and provide real-time automatic failure prediction and diagnosis system that can be used in connection with the building automation system. .

Under these circumstances, the US NIST proposed a rule-based air conditioner fault detection and diagnosis method. In this case, the conventional AHU Performance Assessment Rule (APAR) is a diagnostic tool that uses expert rules inferred from a material balance relationship, an energy balance relationship, and a temperature distribution for each site to detect a failure of the air conditioner. The control signal of each part is used to determine the operation mode, and expert rules corresponding to each operation mode are used to determine whether there is a mechanical failure or a controller failure.

Then, the conventional rule-based air conditioner fault detection and diagnosis method proposed by the US NIST, that is, the air conditioner performance evaluation rule (APAR) will be described in more detail.

First, the operation mode will be described. The expert rule used for fault detection and diagnosis is for a single supply duct variable airflow or constant airflow air conditioner with equipment and controls for heating coils, air conditioning coils and economizers. The rules focus on the temperature control of the air conditioner and the temperature distribution of the parts. Therefore, only components and controllers directly related to temperature are dealt with.

The temperature controller of the air conditioner adjusts the air supply temperature supplied from the duct at the rear of the air supply fan to a set value. The outside air is sucked into the air conditioner and mixed with the air circulated from the building to control the temperature while passing through the heating and cooling coils. The operation mode of the air conditioner can be classified into four types according to the season to maintain the air supply temperature and ventilation during the use period. 1 illustrates the relationship between the heating coil valve, the cooling coil valve and the mixed air damper for the four operation modes. Four operating modes are determined by various thermal relationships, including internal and external thermal loads.

In heating mode of mode 1, in order to maintain the heating temperature, the heating coil valve is adjusted to adjust the supply air temperature to a set value, and the cooling coil valve is closed. The mixed air damper is left open with a minimum degree of opening to maintain minimal ventilation.

When the cooling load increases, the operation mode of the AHU (Air Handling Unit) is changed from the heating mode to the mode 2 (mode 2) that is the cooling mode using the outside air. In mode 2, the heating and cooling coil valve is closed and the mixed air damper is adjusted to maintain the supply air temperature at the cooling set point.

As the cooling load increases further, the mixed air damper will fully open and shut down and switch to mode 3, a mechanical cooling mode. When the air conditioner is operated in the mechanical cooling mode, the cooling set point is maintained by the control of the cooling coil valve, and the heating coil valve is closed. The outdoor damper will remain at its maximum or minimum.

Mode 3 is an area where mechanical cooling is performed when the outdoor damper is 100% open, and mode 4 is an area where mechanical cooling is performed when the outdoor damper is in a minimum state. 2 summarizes the relationship between the operation mode and the control signal depending on the temperature.

Meanwhile, the 'expert rule' for air conditioner performance evaluation is as follows.

The basis of the method for fault detection is an expert rule that can evaluate the performance of the air conditioner. The APAR performance diagnosis tool is a summary of the air conditioner's rules for computer implementation. The APAR diagnostic tool used control signals and occupancy information to determine the mode of the air conditioner and defined a set of rules that could specify the relationship between the temperature sensors applicable to the mode.

The rule used a qualitative model that represents the relationship between the measured temperature signal and the control signal. Since four operation modes are used in AHU, the rules applicable to each mode are set separately. The operation mode can be determined by the digital control signal of the heating / cooling coil valve and the air mixing damper.

Once the operating mode has been established, the necessary rules can be generated using the measurement signals used to control the AHU based on the law of conservation of mass and energy and the temperature distribution.

First, in heating mode 1, the control valve of the heating coil is adjusted to maintain the air supply temperature at the set point, the cooling coil is closed and the external air suction damper is kept at the minimum position. The rule based on the measured temperature is as follows, and when the formulas described below are satisfied, it means 'failure'.

Rule 1.Tsa <Tma + ΔTsf-ε _t

Rule 2.For | Tra-Toa | ≥ΔTmin: | Qoa / Qsa-(Qoa / Qsa) min |> ε _f

Where Tsa is the supply air temperature, Tma is the mixed air temperature, ΔTsf is the temperature increase through the air supply blower, Tra is the circulating air temperature, Toa is the outside air temperature, ΔTmin is the minimum allowable temperature difference between the recovered air temperature and the outside air temperature, Qoa / Qsa can be expressed as the temperature ratio (Tma-Tra) / (Toa-Tra) as the outside temperature ratio, (Qoa / Qsa) min is the minimum allowable value of the outside temperature ratio, ε _t is the tolerance value according to the thermometer, And ε _f is the error tolerance (function of temperature measurement error) related to the flow rate.

Rule 1 shows the inconsistency between the supply air temperature and the mixed air temperature. In heating mode, the air supply temperature must be higher than the mixed air temperature. When considering the temperature increase in the blower, the sum of the temperature increase in the blower and the mixed air temperature is added. The air supply temperature value should be higher. Rule 2 is regarded as a failure when the value of the outside air taken into the air conditioner is too high or too low. The rule is applied only when the temperature difference (Tra-Toa) is above the tolerance in consideration of the error of the temperature measurement. ε _t , ε _f , ΔTsf, and ΔTmin are preset values by the user. Regarding the control signal, the rule can be made as follows.

Rule 3. | u _hc -1 | ≤ ε _hc and Tsa, s-Tsa ≥ ε _t

Rule 4. | u _hc -1 | ≤ ε _hc

Here, u _hc is a normalized heating coil valve control signal [0, 1], u _hc = 0 is the valve is closed, u _hc = 1 is 100% open. Tsa, s is the air supply temperature set value, ε _hc is the allowable value of the heating coil control signal.

The control signal of the valve is adjusted by using analog signal output value such as 4 ~ 20mA of current output or 1 ~ 5Volt of voltage output according to the type of controller. The output of 4mA or 1Volt corresponds to the state where the heating or cooling valve is completely closed. The expression represented by [0] in this specification corresponds to this and is equivalent to an output of 0%. In addition, the output of 20mA or 5Volt corresponds to the state in which the heating or cooling valve is fully open. The expression represented by [1] in this specification corresponds to 100% output. As described above, in the air conditioning system, 0 and 1 are denoted as [0, 1] for the purpose of understanding the technology because the above output methods are often different for each controller.

Rule 3 indicates an uncontrollable condition in which the cooling coil valve is fully open but fails to maintain the set temperature of the air supply. Rule 4 represents a situation in which attention is needed to maintain the maximum value of the control value under different conditions. ε _hc and ε _t are values determined by the operator according to facility characteristics. The control signals of the cooling coil valve and the mixed air damper should always be checked, the cooling coil valve should be closed for mode 1 and the mixed air damper should be set to the minimum of the external air damper.

Second, in the air cooling mode (mode 2), the air supply temperature is controlled to a set value using a mixed air damper, and the cooling coil and the heating coil are closed. The rules of mode 2 are as follows.

Rule 5.Toa> Tsa, s-ΔTsf + ε _t

Rule 6.Tsa> Tra-ΔTrf + ε _t

Rule 7.Tsa-ΔTsf-Tma | > ε _t

Here, ΔTrf is a temperature rise value through the circulation blower. Rule 5 is when the outside temperature is too high in this mode. Rule 6 shows the mismatch between the air supply temperature and the circulating air temperature. The supply air temperature should be lower than the circulation air temperature plus the temperature rise through the circulation blower. Rule 7 shows the mismatch between the supply air temperature and the mixed air temperature. Since the cooling and heating coils do not operate, the air supply temperature should be approximately equal to the sum of the mixed air temperature and the temperature rise through the air supply blower. ε _t , ΔTsf and ΔTrf are driver settings.

Third, in the cooling mode (mode 3) using the cooling coil in the state of 100% air damper, the set value of the air supply temperature is controlled by the cooling coil valve.In the mixed air damper, the air intake damper is opened to the maximum and the heating coil valve is closed. . The rules in mode 3 are as follows.

Rule 8.Toa <Tsa, s-ΔTsf-ε _t

Rule 9.Toa> Tco + ε _t

Rule 10. | Toa-Tma | > ε _t

Rule 11.Tsa> Tma + ΔTsf + ε _t

Rule 12.Tsa> Tra-ΔTrf + ε _t

Where Tco is the change over air temperature that changes from mode 3 to mode 4. Rule 8 is the case where the outside temperature is too low to apply mode 3, and Rule 9 is the case where the outside temperature is too high. Rules 10 to 12 show the temperature mismatch between the outside air temperature and the mixed air temperature, the air supply temperature and the mixed air temperature, and the air supply temperature and the circulating air temperature. ε _t , ΔTrf and ΔTsf driver settings. Rules 3 and 4 (Rules 3 and 4) may apply the same rule to the cooling mode by the cooling coil. The rules are as follows.

Rule 13. | u _cc -1 | ≤ ε _cc and Tsa, s-Tsa ≥ ε _t

Rule 14.u _cc -1 | ≤ ε _cc

Here, u _cc is a normalized cooling coil valve control signal [0, 1], ucc = 0 is a valve closed state, ucc = 1 is 100% open, and epsilon _cc is an allowable value of a cooling coil control signal.

Similarly, Rule 13 is an uncontrollable condition in which the cooling coil valve is not opened and does not maintain the set point of the supply air temperature and shows a high value. In Rule 14, the air supply temperature is within the allowable range. Attention is needed because the control limit state is reached. ε _cc and ε _t are user set values.

Fourth, in the control mode (mode 4) using the cooling coil at the minimum opening degree of the external air damper, the air intake temperature is controlled by using the cooling coil valve with the external air suction damper at the minimum position. In mode 4 the rules are as follows:

Rule 15.Toa <Tco-ε _t

Rule 16.Tsa> Tma + ΔTsf + ε _t

Rule 17.Tsa> Tra-ΔTrf + ε _t

Rule 18.For | Tra-Toa | ≥ΔTmin: | Qoa / Qsa-(Qoa / Qsa) min |> ε _f

Rule 15 indicates that the ambient temperature is too low for mode 4. Rules 16 and 17 indicate incompatibility between supply temperature and mixed air temperature and supply temperature and circulating air temperature. Rule 18 indicates that the proportion of outside air entering the air conditioner is too low. ε _t , ε _f , ΔTmin, ΔTrf and ΔTsf are driver settings.

Rules 13 and 14 may also apply to mode 4. Repeating rules 13 and 14 for mode 4, we get

Rule 19. | u _cc -1 | ≤ ε _cc and Tsa-Tsa, s ≥ ε _t

Rule 20. | u _cc -1 | ≤ ε _cc

The descriptions of Rules 19 and 20 are the same as those of Rules 13 and 14.

Fifth, the following rules are for the unknown mode based on the control signals of the cooling coil valve, the heating coil valve, and the mixed air damper. Failure of any of the following rules is a fault condition.

Rule 21.u _cc > ε _cc , u _hc > ε _hc and ε _d <u _d <1-ε _d

Rule 22.u _hc > ε _hc and u _cc > ε _cc

Rule 23.u _hc > ε _hc and u _d > ε _d

Rule 24.ε _d <u _d <1-ε _d and u _cc > ε _cc

Here, u _d is the normalized mixed air damper control signal [0, 1], when u _d is 0, the air intake damper is closed, and u _d = 1 is 100% open. And ε _d is the allowable value of the mixed air damper control signal.

Rule 21 states that the mixed air damper, cooling coil valve and heating coil valve are controlled simultaneously. Rule 22, 23, and 24 (Rule 22, 23, 24) is a state in which at least two valves or dampers are driven simultaneously. ε _cc , ε _hc and ε _d are user set values.

Sixth is the rule applicable to all living modes, and it is regarded as a failure if the following conditions are met.

Rule 25. | Tsa-Tsa, s | > ε _t

Rule 26.Tma <min (Tra, Toa)-ε _t

Rule 27.Tma> max (Tra, Toa) + ε _t

Rule 25 is the case where the supply air temperature does not maintain the set value, and rules 26 and 27 require that the temperature of the mixed air be determined as the value between the maximum and minimum of the outside air and circulating air temperature. Indicates that ε _t is the operator set point. Rule 25 is a rule that is satisfied at the same time when rule 3, 13 or 19 is satisfied, to find a failure when these rules are not satisfied.

Seventh, frequent mode changes may be caused by instability of the supervisory control or the field controller, so that the mode changes within a given time period may be detected and detected.

Rule 28. [Mode changes per unit time]> MTmax

Where MTmax is the number of allowable mode changes per given time.

The following rules are used to summarize the rules used in the APAR Performance Diagnostic Tool.

All the rules summarized in Table 1 above are expressed as failures when the corresponding conditions are met. Table 2 below summarizes the faults that can satisfy each rule.

Here, not all the failure situations are listed in Table 2, but the failures that can be detected by the rules are summarized and the possible effects of the failures associated with each rule are examined. The defined effects include comfort, quality of internal air, energy, maintenance and plant life, and in some cases one or more serious effects may occur.

In particular, the most important component of an HVAC system is temperature. Maintaining the specified indoor temperature and the specified air supply temperature is of paramount importance. Therefore, it is most important to consider the temperature measuring sensor in the fault diagnosis algorithm, and the fault detection method proposed by the above-described APAR method is also concentrated in this part.

However, the above-mentioned conventional APAR method alone cannot accurately diagnose the cause and location of all failures of the air conditioning system, and merely detects the presence or failure of a failure that satisfies the rules. There was a realistic problem required.

That is, in modern times, as air conditioning facilities become more complicated, many failures are prone to occur, while maintenance is becoming difficult. Therefore, the fault detection and diagnosis tool for air conditioners should be robustly designed to be applied to various systems. The above-mentioned APAR is applied to real buildings only after the diagnosis range and performance are reviewed using a device installed in a simulation or laboratory. There is a problem that can be done.

In addition, the conventional rule-based air conditioner fault detection and diagnosis method (APAR) described above should determine at least two faults detected by the rule-based method determined in each mode in which the HVAC system operates. Since there is a high failure estimation method, a single failure cannot be detected.

That is, the APAR method means that all the variables used in the equation are likely to fail when the failure determination equations are satisfied. Assuming that the "A" element (or variable) has failed in the system and the failure is determined using the APAR method, all equations including the "A" element (or variable) will satisfy the failure determination equation. There is a drawback that one element fails and it is not possible to pinpoint it, and many other elements, including the "A" element, also assume a failure.

As a result, according to the above-described APAR estimation method, it is possible to diagnose a failure when multiple failures occur at the same time, but when a single failure occurs, it is accurate about the failure factor or the failure part of which component has failed. But it is difficult to find a quick decision. For example, when only Tsa is a failure (meaning that the temperature sensor measuring Tsa is a failure) in the failure determination formula according to Rule 6 and 7, in Mode 2, all of the failure determination formulas according to Rule 6 and 7 are satisfied. The Tsa, Tra, and Tma variables all fail or one or two of them are determined to be faulty, which leads to a problem of ambiguity in the determination of a specific part.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a signal for a failure part signal for a specific element in order to overcome the disadvantage of multiple failure estimation, which is a limitation of the conventional APAR algorithm. A detailed classification rule-based fault detection and diagnosis method and an apparatus using such a method in an air conditioning system to enable a single fault detection to know specific information about positive or negative directionality. To provide.

That is, in the present invention, the purpose of determining the directionality (positive and negative failure) when determining the failure of the temperature sensor portion, the purpose of the determination of the directionality (positive failure, negative failure) is specifically What it means is:

In general, it is assumed that the temperature measured by the temperature sensor installed in the air conditioning system is reading the air supply temperature of 18 ° C in the summer (the summer air supply temperature is set to 18 ° C). In this case, a positive fault means a fault that indicates a positive value higher than the actual temperature, and a negative fault indicates a fault that indicates a negative value lower than the actual temperature.

If it is assumed that the temperature measured by the air supply temperature sensor installed in the air conditioning system in the summer is reading a temperature as high as + 10 ℃ due to a positive failure than the normal state, the temperature is not read as the normal air supply temperature of 18 ℃. This means reading the temperature at 28 ° C. In this case, the controller of the air conditioning system determines that the air supply setting temperature has not reached 18 ° C. and continues to operate, and operates with the full performance of the system. Therefore, people living in buildings feel uncomfortable due to continuous cooling and energy consumption is much higher than before.

Likewise, assuming that the temperature measured by the air supply temperature sensor installed in the air conditioning system is reading lower than -10 ℃ due to a negative fault than the normal state, the temperature is not read as the normal air supply temperature of 18 ℃. It is meant to read the temperature at 8 ° C. In this case, the controller of the air conditioning system has already determined that the air supply temperature set point is 18 ℃. That is, it is determined that the temperature is much lower than the air supply temperature set value of 18 ℃ to stop the operation of the cooler. Therefore, people who live in the building will be judged that the cooling is not done and feel uncomfortable.

The fault diagnosis method according to the present invention has the advantage of reducing energy consumption and minimizing the inconvenience of residents by determining in real time such a positive (+) fault and a negative (-) fault by informing the air conditioning system manager. This can be used more effectively in diagnosing the failure of the HVAC system by informing the administrator of failure-related information than simply classifying a single failure factor.

In addition, the present invention makes it easy to achieve compatibility with the HVAC system installed in the existing medium and large buildings by using the signals of the low-cost sensor and the existing temperature sensor, thereby making the air conditioning system actually applicable to the existing building The present invention provides a method for detecting and diagnosing faults using a detailed classification rule-based method and a device using the same.

In order to achieve the above object, the method of detecting and diagnosing single site failures of a detailed rule type rule-based method in an air conditioning system according to the present invention,

A) assigning a limit value required for the diagnosis to a constant constant and collecting measured data values from the elements installed in the air conditioner system;

B) determining whether an outside temperature factor is abnormal among the data values;

C) determining whether the outside temperature is within a predetermined range and automatically selecting a mode corresponding to each range; And

D) After reading the predetermined limit value in the selected mode, the information on the positive or negative directionality of the signal of the failure region and the signal of the failure region is determined by a plurality of failure determination formulas assigned to the mode. However, when satisfying the thermodynamic judgment equations of each part of the system and simultaneously satisfying a plurality of failure judgment equations including two or more related temperature factors, the common temperature factors included in the failure judgment equation are determined as the failure factor. Making;

Characterized in that it comprises a.

Hereinafter, an apparatus for diagnosing single site failure of a detailed classification type rule-based method in an air conditioning system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Classification rule-based fault detection and diagnosis device

FIG. 2 is a diagram illustrating a detailed classification rule-based failure diagnosis apparatus in an air conditioning system according to an embodiment of the present invention, and the failure of the classification rule-based method in an air conditioning system according to an embodiment of the present invention. 2, the first and second tachometers 110 and 120, the first to fourth potentiometers 210 to 240, the outside air temperature sensor 310, the air supply temperature sensor 320, and the mixed air as illustrated in FIG. 2. The temperature sensor 330, the circulating air temperature sensor 340, the outdoor reference temperature sensor 350, and the central control unit 400 are configured.

The first tachometer 110 measures the rotational speed of the supply blower 10 according to the input signal of “4-20 mA” output from the central controller 400, and then measures the rotation speed of the first tachometer 110 to the central controller 400. The second tachometer 120 measures the rotational speed of the return blower 20 according to the analog input signal of “4-20 mA” output from the central control unit 400, and then outputs the central control unit. It serves to output to (400). In this case, in implementing the present invention, instead of the first and second tachometers 110 and 120, the first and second frequencies for measuring the frequencies of the air supply fan 10 and the ventilation air blower 20 according to an arbitrary input signal may be measured. It is also possible to configure the two frequency meter (130, 140).

In addition, the first potentiometer 210 is installed in the driving unit of the VAV damper 50 and measures the voltage output value according to whether the VAV damper 50 is driven, and outputs it to the central controller 400. The second potentiometer 220 is installed in the driving unit of the external air damper 60 measures the voltage output value according to whether the external air damper 60 is driven and outputs it to the central control unit 400. 230 is installed in the driving unit of the exhaust damper 70 measures the voltage output value according to whether the exhaust damper 70 is driven to output to the central control unit 400, the fourth potentiometer 240 is mixed It is installed in the driving unit of the damper 80 serves to measure the voltage output value according to whether the mixed damper 80 is driven and outputs it to the central control unit 400.

On the other hand, the outside temperature sensor 310 measures the outside air temperature and serves to output to the central control unit 400, the air supply temperature sensor 320 measures the air supply temperature and then outputs to the central control unit 400 And, the mixed air temperature sensor 330 measures the mixed air temperature and then outputs to the central control unit 400, the circulating air temperature sensor 340 measures the circulating air temperature and then the central control unit The outside reference temperature sensor 350 measures a reference value for diagnosing an abnormality of the outside temperature sensor 310, and then outputs the reference value to the central control unit 400. .

In addition, the central control unit 400 includes the first and second tachometers 110 and 120, the first to fourth potentiometers 210 to 240, the outside air, outside air reference, air supply, mixed air, and circulating air temperature sensor 310. To 350) detect the presence or absence of failures of the components driven in the mode, and then display the failure presence result to the operator. Here, the central control unit 400 is the first and second tachometers 110 and 120, the first to fourth potentiometers 210 to 240, the outside air, outside air reference, air supply, mixed air and circulating air temperature sensor ( As a method of obtaining the measurement result values of 310 to 350, a moving average method may be used, thereby minimizing an error in failure diagnosis due to an error value that may occur according to the measurement.

At this time, the central control unit 400 diagnoses the failure of the air supply fan 10 or the ventilation fan 20, respectively, the output value of the first and second tachometers 110, 120 and the air supply blower ( 10) Or, if the ratio of the signal (4-20mA) input to the ventilation blower 20 exceeds the preset limit value, each fault is diagnosed.

In addition, the central control unit 400 diagnoses the failure of the VAV damper 50, the external air damper 60, the exhaust damper 70, or the mixed damper 80, respectively, and the first or fourth potentiometer 210. If the ratio between the voltage output value of the reference signal 240 and the open command input of the damper commanded by the controller exceeds the preset limit value, the fault is diagnosed.

Classification and Rule-Based Single Site Failure Detection and Diagnosis

Then, the failure diagnosis process for each mode performed by the central control unit 400 in the operation process of the single-part failure diagnosis device of the classification type rule-based method in the air conditioning system according to an embodiment of the present invention having the configuration as described above. This will be described in detail. FIG. 3 is a flowchart of a method for diagnosing and detecting a failure of a classification rule-based method in an air conditioning system according to an embodiment of the present invention, and FIG. 4 is a method for fixing and detecting in the mode 1 of FIG. 3. 5 is a detailed flowchart of the fixed diagnosis and detection method in mode 2 of FIG. 3, FIG. 6 is a detailed flowchart of the fixed diagnosis and detection method in mode 3 of FIG. 3, and FIG. 7 shows a detailed flowchart of the fixed diagnosis and detection method in mode 4 of FIG. 3.

On the other hand, as described above, the most important component of the HVAC system is temperature. Maintaining the specified indoor temperature and the specified air supply temperature is of utmost importance. Therefore, it is most important to consider the temperature measuring sensor in the fault diagnosis algorithm, and the fault detection method proposed by APAR is also concentrated in this part.

As pointed out above, the APAR method has a disadvantage in that it does not know the exact failure factor or location due to failure detection of two or more factors. The fault detection and diagnosis method based on the classification rule-based algorithm according to the present invention has been developed as a method for improving the problem.

Limited value  And data collection steps

As shown in Fig. 3, the start of the classification rule-based fault detection and diagnosis algorithm according to the present invention is to designate a limit value necessary for fault diagnosis as a constant constant. This means defining values of ε, ΔT, etc., used in all relations.

Once the system's limits are selected, signals such as voltage, temperature, and pressure from elements or measurement equipment installed in the HVAC system are monitored in real time. The measured data values are sent to the signal collector to minimize the errors in troubleshooting due to the error values that can be generated by using the moving average method.

Mode selection  step

As illustrated in FIG. 3, the central control unit 400 selects a mode based on the ambient temperature T _OA measured in the HVAC system when data is obtained using the moving average concept. Restrictions related to the selection of the operation mode require "T _{OA , HT, set} , T _{OA , cool, set} , T _{OA , cool, min, set} ", which are programmed to values that can be changed as necessary. In the diagnostic algorithm according to the present invention, an element for applying the energy equation for the first time in determining the failure of each element of the air conditioning system is an external temperature (T _OA ) sensor. The signal of the outside air temperature (T _OA ) sensor is compared with the reference outside air temperature (T _{OA , ref} ) sensor signal as a reference, and it is determined that there is no abnormality if the difference in the value is within a limited value (for example, 1.5 K). If it is determined that the signal of the outside temperature (T _OA ) sensor measured here is a failure signal, it should be diagnosed first. If it is determined that the failure is not a failure, the mode 1 to 4 may be used according to the condition that meets the various setting criteria of FIG. Move to any one to perform the failure diagnosis determination in the mode.

That is, the method of setting the operation mode in the present invention depends entirely on the "outside air temperature". After the operation mode is first selected according to the outside temperature, coefficient values such as the maximum damper opening value, the minimum damper opening value, and the error value of the heating / heating valve are applied to each operation mode (modes 1 to 4).

On the other hand, the method of the central control unit 400 to determine whether the outside temperature (T _OA ) is abnormal before the mode selection is determined to be normal when the following [Equation 1], and if it is not satisfied it is determined to be a failure. .

Where T _OA is the outside temperature, T _{OA .ref} is the outside reference temperature, and ε _OA is the allowable value of the outside temperature.

mode  1 Detection and Diagnosis Method

As shown in FIG. 4, the central control unit 400 selects the current mode as the mode 1 when the following Equation 2 is satisfied.

Here, T _OA is the outside temperature, and T _OA , _{HT, set} is the outside air heating coil set temperature.

Mode 1 is the operation method to keep the indoor temperature by blocking the outside air in winter and continuously heating the ventilation, and the open air damper should be 100% closed. Therefore, the central control unit 400 initially measures the data of each element, and first determines whether the open air damper is open. In mode 1, the open signal of the external damper output from the automatic control unit is generated to close 100%. At this time, if the external air damper is not 100% closed, the central control unit 400 compares the input signal and the output signal supplied to the damper, and if it is not determined to be a failure, the external air temperature is determined again to determine modes 2, 3, and 4 Change to one control mode.

The central control unit 400 checks the signal supplied to the heating coil after diagnosing whether the signal T _OA of the outside temperature in the control mode is broken by the method of [Equation 1] again. In this case, if there is no output signal supplied to the heating coil 30, a failure of the heating coil 30 is suspected and should be diagnosed as a failure.

In this case, the method of diagnosing the failure of the heating coil 30 in the mode 1 by the central control unit 400 is determined to be normal when the following Equation 3 is satisfied, and is determined to be a failure when not satisfied. .

Here, V _{HT .set} is an output signal supplied to the heating coil.

On the other hand, the present invention satisfies the thermodynamic determination equation of each part of the system by using equations including temperature factors T _OA , T _RA , and T _ma that are related to each other in mode 1, and faults including temperature factors that are related to each other. If the judgment is satisfied, it is judged as a failure factor. The reason for such a determination is possible, as described above, because the present invention corresponds to an algorithm that accurately finds only when one element is a failure. It is assumed that the present invention is not applicable when multiple elements are simultaneously failed. This is because Such matters may be determined and applied in the same manner to the following mode.

At this time, the central control unit 400 may determine the failure of the mixed air temperature sensor using the following [Equation 4] and [Equation 5] in the next diagnostic step. If Equation 4 is satisfied, it is determined to be a failure, and if not satisfied, it is determined to be normal.

Where T _OA is the outside air temperature, T _ma is the mixed air temperature, and ε _ma is the allowable value due to the temperature measurement error.

In mode 1, the mixed air temperature in the air conditioner is typically higher than the ambient air temperature. If the mixed air temperature is lower than the outside air temperature in winter, it may be regarded as a failure due to a temperature (T _ma- ) having a negative tendency than the normal temperature of the mixed air temperature.

At this time, the central control unit 400 determines that the positive (+) mixed air temperature is broken when the following Equation 5 is satisfied in the next diagnosis step, and normal if not satisfied.

Where T _SA is the air supply temperature, T _ma is the mixed air temperature, ε _t is the allowable value due to the temperature measurement error, T _OA is the outside air temperature, and T _RA is the circulating air temperature.

Since the analysis of the failure condition of T _ma -is performed in the previous step, satisfying [Equation 5] is due to the failure condition (T _ma +) where the mixed air temperature is positive than the normal value. Corresponding.

Then, the central control unit 400 may determine whether there is a failure of the air supply temperature sensor using the following Equation 6 and Equation 7 in the next diagnosis step. If Equation 6 is satisfied, it is judged as a negative fault of the air supply temperature sensor, and if not satisfied, it is determined to be normal.

Where T _SA is the air supply temperature, T _ma is the mixed air temperature, and ε _SA is the allowable value due to the temperature measurement error.

In mode 1, the air supply temperature in the air conditioner is typically higher than the mixed air temperature. If the air supply temperature is lower than the mixed air temperature, the air supply temperature is displayed as a temperature (T _SA- ) which tends to be negative (-) than the normal temperature, it can be determined that the failure.

Then, the central control unit 400 is a failure condition (T) indicating that the air supply temperature is a positive value (+) than the normal value when the first formula and the second formula in the following Equation 7 are simultaneously satisfied in the next diagnostic step (T). _SA +), the air supply temperature sensor T _SA + is determined to be abnormal, and when not satisfied, it is determined to be normal.

Where T _SA is the air supply temperature, T _{SA .set} is the air supply set temperature, ε _SA is the air supply temperature tolerance value, ε _hc is the tolerance coefficient of the heating coil control signal, u _hc is the normalized heating coil valve control signal [0, 1].

In the process so far, abnormal factors for T _OA , T _ma , and T _SA can be determined.

Thereafter, the central control unit 400 may determine whether the ventilation temperature sensor is faulty using the following Equation 8 and Equation 9 in the next diagnosis step. If Equation 8 is satisfied, it is judged as a negative fault of the ventilation temperature sensor, and if not satisfied, it is determined to be normal.

Where T _RA is the circulating air temperature, T _ma is the mixed air temperature, T _OA is the outside air temperature, and ε _t is the allowable value due to the temperature measurement error.

In mode 1, the circulating air temperature in the air conditioner is usually not significantly different from the mixed air temperature. If the ventilation temperature is lower than the mixed air temperature minus the outside air temperature, the circulating air temperature is indicated as a temperature (T _RA- ) having a negative tendency than the normal temperature and may be regarded as a failure.

Then, when the central control unit 400 satisfies Equation 9 below, the central control unit 400 determines that the circulating air temperature corresponds to a failure condition (T _RA +) indicating a positive value (+) rather than the normal value, and circulating air. It determines with abnormality of the temperature sensor _TRA +, and when it is not satisfied, it determines with normal.

Therefore, when the central control unit 400 satisfies the following Equation 9 in diagnosing the abnormality of the circulating air temperature (T _RA ) in the next diagnosis step, the ventilation temperature is a positive (+) value than the normal value. It is determined that it corresponds to the failure condition (T _SA +), and it is determined to be a failure.

Here, T _ma is the mixed air temperature, ε _f is the allowable value by the error related to the flow rate, T _OA is the outside air temperature, T _RA is the circulating air temperature.

At this time, satisfying the relational expressions of [Equation 8] and [Equation 9] in the state that the abnormality for T _OA , T _ma , T _SA does not occur means an abnormality for the circulating air temperature (T _RA ) factor. It is. Finally, if it is not determined that the failure factors in the above-mentioned conditions of the energy equation, it is determined that the HVAC system is operating normally, and thus the central control unit 400 performs the first data collection process again.

mode  2 fault detection and diagnosis method

As shown in FIG. 5, the central control unit 400 selects the current mode as the mode 2 when the following Equation 10 is satisfied as a result of the above-described mode selection step.

Here, T _OA is the outside air temperature, T _{OA , HT, set} is the outside air heating coil set temperature, T _{OA, cool, set} is the outside air cooling coil set temperature.

Mode 2 is an operation method that maintains the indoor temperature by blocking heating coils and cooling coils and continuously ventilating under the condition of outside air where the temperature is higher than in winter, such as spring and autumn. Mode 2 operates to satisfy the conditions of air supply temperature and room temperature only by adjusting the opening degree of the external air damper.

When the current mode is selected as the mode 2, the central control unit 400 first measures data of each element, and then first determines whether the outside temperature T _OA is abnormal using Equation 1 above. Here, if it is determined that the signal of the ambient temperature (T _OA ) measured is a fault signal, it should be diagnosed first.

에 대한 정의가 필요하다. 이는 [수학식 11]로 표현된 것 과 같이 댐퍼의 개도, 외기온도 및 환기온도의 비율에 의해 정의된 ‘기준 혼합공기 온도(reference mixed air temperature)’를 나타낸다. In mode 2

We need a definition of This represents the 'reference mixed air temperature' defined by the ratio of the damper opening degree, the outside air temperature and the ventilation temperature, as expressed by [Equation 11].

는 기준 혼합공기온도이고, T_OA는 외기온도이고, T_{OA ,HT,set}은 외기 난방코일 설정온도이며, T_{OA ,cool,set}은 외기 냉방코일 설정온도이다. here,

Is the reference mixed air temperature, T _OA is the outside air temperature, T _{OA , HT, set} is the outside air heating coil set temperature, and T _{OA , cool, set} is the outside air cooling coil set temperature.

Before using the trouble diagnosis equation, it is possible to first determine whether the external damper is broken. The open signal of the damper is represented by voltage. Mode 2 aims to keep the indoor temperature at the appropriate set point by introducing the outside air, so that the goal cannot be achieved unless the outdoor damper is activated. Therefore, after setting the minimum value of the external air damper as shown in [Equation 12], if the damper opening degree is smaller than this, the damper should be checked for failure.

V _{OA , damper}   < V _{OA , damper, min}

Here, V _{OA and damper} are opening signals of the external air damper, and V _{OA , damper and min} are minimum opening signals of the external air damper.

According to Equation 13 below, the outside air temperature T _OA cannot be an absolute higher temperature than the air supply set temperature T _{SA , set} . Therefore, if Equation 13 is satisfied, it is determined that the air supply set temperature T _{SA, set} is incorrectly specified.

Where T _OA is the outside temperature, T _{SA .set} is the air supply set temperature, and ε _t is the permissible value due to the temperature measurement error.

In mode 2, the operation of the cooling coil and the heating coil is stopped, so when the valves of the cooling coil and the heating coil are opened, a failure is checked.

In the next step, a failure of the negative directionality T _ma -of the mixed air temperature can be detected. Mode 2 to a spring, because the outside temperature of the season, such as a fall is also available for the there is a lower temperature than the temperature inside the air conditioner system, the air inlet when the temperature of the T _ma than T _OA low configuration, the signal T _OA is not a malfunction If Equation 13 is satisfied, it is determined that the temperature of the mixed air is a fault having a negative directionality, otherwise it is determined to be normal.

Where T _ma is the mixed air temperature, T _OA is the outside air temperature, and ε _MA is the allowable value due to the mixed air temperature measurement error.

In the next step, the actual mixed air temperature and the reference mixed air temperature can be compared to determine the directionality at the time of the failure of the circulation air temperature (T _RA ). Using Equation 15, the actual mixed air temperature is higher than the standard mixed air temperature in which outside air and ventilation are mixed. Since it is already determined that T _OA is a normal state, it can be seen that the value of the reference mixed air temperature by T _RA is a problem. Therefore, in order to satisfy Equation 15, a fault having a directionality of T _RA -must occur. If the actual mixed air temperature does not satisfy [Equation 15], it is not a failure of T _RA −, and thus it is possible to determine the failure of T _RA + using Equation 16.

는 기준 혼합공기온도이고, T_ma는 혼합공기온도이다.here,

Is the reference mixed air temperature and T _ma is the mixed air temperature.

The operating condition in mode 2 is to introduce the outside air into the air conditioner system and to introduce it into the room through the air blower. Therefore, it is difficult to generate a large temperature difference between the room temperature and the system temperature. If the failure of T _RA is not diagnosed, T _ma + failure can be diagnosed by comparing the mixed air temperature and the ventilation temperature as shown in [Equation 17].

Where T _ma is the mixed air temperature, T _RA is the circulating air temperature, and ε _t is the allowable value due to the temperature measurement error.

If it reaches this stage, it is possible to detect and diagnose the failure of T _OA , T _RA and T _ma , including directionality.

In the next step, the central control unit 400 may diagnose whether there is an abnormality in the air supply temperature T _SA using Equation 18 below, and if it satisfies Equation 18 below, it is determined to be a failure. If it is not satisfied, it is determined to be normal. In mode 2, the temperature difference between the mixed air temperature and the air supply temperature passing through the air conditioner system is not large. The temperature rise of the air during the passing of the air blower may occur insignificantly, but this does not consider the temperature rise of the air passing through the blower because it does not show a big difference. Therefore, T _SA is unlikely to show a significantly smaller value than T _ma . If Equation 18 is satisfied, it is diagnosed as a fault having a T _SA − direction.

Where T _SA is the air supply temperature, ε _t is the allowable value due to the temperature measurement error, and T _ma is the mixed air temperature.

At this time, if the central control unit 400 does not satisfy the above Equation 18, the air supply temperature T _SA using the first equation (left) and the second equation (right) of Equation 19 below. It is possible to diagnose the abnormality of +), and if it satisfies the following [Equation 19], it determines the supply air temperature (T _SA +) factor as a failure, and if not satisfactory.

Where T _SA is the air supply temperature, T _RA is the circulating air temperature, T _ma is the mixed air temperature, and ε _t is the allowable value due to the temperature measurement error.

Therefore, by using the failure determination proceeded so far, it can be known whether the failure of T _OA , T _ma , T _SA .

If the condition that does not satisfy the relational expression mentioned so far to determine the failure factor, it is determined that the HVAC system is operating normally, the central control unit 400 again processes the data collection process.

mode  3 fault detection and diagnosis method

As shown in FIG. 6, the central control unit 400 selects the current mode as the mode 3 when the following Equation 20 is satisfied as a result of the above-described mode selection step.

Here, T _OA is the outside air temperature, T _{OA , cool, set} is the outside air cooling coil set temperature, T _{OA , cool, min, set} is the outside air cooling coil minimum set temperature.

Mode 3 is an operation method that maintains the indoor temperature by controlling the cooling coils under the condition of outside air, where the temperature is slightly higher than in spring and autumn as in early summer. At this time, the opening degree of the outdoor air damper 60 is 100% open, the outdoor air is introduced, and the heating coil 30 is not in operation. That is, only the adjustment of the cooling coil 40 is operated to satisfy the air supply temperature condition.

The central control unit 400 initially measures the data of each element in mode 3 and first determines whether the open air damper 60 is open. The opening signal of the external air damper 60 output from the automatic control unit is generated to open 100%. At this time, if the outdoor air damper 60 is not 100% open, the central control unit 400 compares the input signal and the output signal supplied to the outdoor air damper 60, and if it is not determined to be a failure, the external air temperature is reset again. By judging, the control mode is changed to one of the modes 2, 3 and 4.

If a signal is output from the heating coil 30, there is a possibility that it is operating in mode 1, and thus the failure detection process of mode 1 is used.

In the following process, the central control unit 400, when no signal is output from the heating coil 30, the fault for the outside temperature (T _OA ) factor by using a condition that satisfies three equations in Equation 21 below. Diagnose whether or not. The failure of the external temperature (T _OA ) factor is diagnosed once because it is diagnosed at the beginning of mode 3.

T _OA  < T _{SA , set}  -ε _t

T _OA  > T _co  + ε _t

| T _OA  - T _ma | > ε _t

Where T _OA is the ambient temperature, T _{SA .set} is the air supply set temperature, ε _t is the allowable value due to the temperature measurement error, T _CO is the conversion temperature from mode 3 to mode 4, and T _ma is mixed air Temperature.

Thereafter, the central control unit 400 determines that a failure is satisfied when [Equation 22] is satisfied in order to first determine a failure of the air supply temperature, and determines that the failure is normal.

T _SA  - T _{SA , set}  > ε _SA

Where T _SA is the air supply temperature, T _{SA .set} is the air supply set temperature, and ε _t is the allowable value due to the temperature measurement error.

Thereafter, when the outside temperature T _OA is normal, the central control unit 400 diagnoses an abnormality of the conversion temperature T _CO changing from the mode 3 to the mode 4 using Equation 23 below. If the following Equation 23 is satisfied, it is determined to be a failure, and if not satisfied, it is determined to be normal. Here, the temperature of the conversion temperature (T _CO ) is a designated value, not a measured value, and therefore, determination of an operator or an expert of the air conditioner system is required.

Where T _OA is the outside temperature, ε _t is the allowable value due to the temperature measurement error, and T _CO is the conversion temperature changing from mode 3 to mode 4.

After diagnosing T _OA and T _CO and T _SA for abnormalities, the central control unit 400 may diagnose whether there is an abnormality with respect to the mixed air temperature T _ma , which may satisfy Equation 24 below. If not, it is determined to be a failure and if not satisfied, it is determined to be normal.

Where T _OA is the outside air temperature, ε _t is the allowable value due to the temperature measurement error, and T _ma is the mixed air temperature.

On the other hand, it is possible to diagnose whether or not the supply air temperature (T _SA ) by using only the relationship of the equation (25) below. The failure of the air supply temperature (T _SA ) has already been diagnosed in [Equation 22]. Therefore, it is once again diagnosed whether the air supply temperature T _SA has failed.

Where T _SA is the air supply temperature, T _ma is the mixed air temperature, ΔT _SF is the temperature rise through the air supply blower, and ε _t is the allowable value due to the temperature measurement error.

Thereafter, the central control unit 400 may diagnose the abnormality of the circulating air temperature T _RA using Equation 26 below in a state where the air supply temperature T _SA is normal, which is described below. If Equation 26 is satisfied, it is determined to be a failure, and if not satisfied, it is determined to be normal. That is, satisfying [Equation 26] in the absence of a failure with respect to the air supply temperature T _SA indicates a failure of the circulating air temperature T _RA .

Here, T _SA is the air supply temperature, T _RA is the circulating air temperature, ΔT _SF is the temperature rise through the air supply blower, ε _t is the allowable value due to the temperature measurement error.

Thereafter, the central control unit 400 diagnoses the failure of the normalized cooling coil valve control signal [0, 1] (u _CC ) using Equation 27 below, ] Is determined to be a failure, and when not satisfied, it is determined to be normal.

Where u _CC is the normalized cooling coil valve control signal [0, 1], ε _CC is the allowable coefficient of the cooling coil control signal, T _SA is the air supply temperature, T _{SA .set} is the air supply set temperature, ε _t Is the allowable value due to temperature measurement error.

The central control unit 400 determines that the HVAC system is in a normal operation if it does not satisfy the relational expression mentioned to determine the failure factor to date, thereby moving back to the first data collection process.

mode  4 Detection and Diagnosis Method

As shown in FIG. 7, the central control unit 400 selects the current mode as the mode 4 when the following Equation 28 is satisfied as a result of the above-described mode selection step.

Here, T _OA is the outside air temperature and T _{OA , cool, min, set} is the minimum set temperature of the air cooling coil.

Mode 4 is an operation method of maintaining the indoor temperature by adjusting the cooling coil 40 in the condition of the outdoor air, such as midsummer, the outdoor air temperature is higher than early summer. At this time, the opening degree of the outdoor air damper 60 is closed by 100% to block the inflow of outside air and to prevent the loss of energy, so that the heater or the heating coil 30 is not in operation.

에 대한 정의가 필요하다. 이는 [수학식 11]로 표현된 것과 같이 댐퍼의 개도, 외기온도 및 환기온도의 비율에 의해 정의된 ‘기준 혼합공기 온도(reference mixed air temperature)’를 나타낸다. Even in mode 4

We need a definition of This represents the 'reference mixed air temperature' defined by the ratio of the damper opening degree, the outside air temperature, and the ventilation temperature, as expressed by Equation (11).

The central control unit 400 initially measures the data of each element in mode 4, and then first determines whether the open air damper 60 is open. The opening signal of the external air damper 60 output from the automatic control unit is generated to be closed by 100%, that is, open by 0%. At this time, if the outdoor air damper 60 is not closed 100%, the central control unit 400 compares the input signal and the output signal supplied to the external air damper 60, and if it is not determined that the failure here, the external air temperature is determined again and the mode Change to one of 2, 3, 4 control mode.

Subsequently, when the signal of the outside temperature T _OA is normal, the central control unit 400 diagnoses the abnormality of the conversion temperature T _CO changing from the mode 3 to the mode 4 using Equation 29 below. However, if the following Equation 29 is satisfied, it is determined to be a failure, and if not satisfied, it is determined to be normal.

Where T _OA is the ambient temperature, T _CO is the conversion temperature from mode 3 to mode 4, and ε _t is the permissible value due to temperature measurement error.

Mode 4 is a summer operation mode, there is no operation of the heating coil, it can be determined as a failure when a signal of the valve of the heating coil is opened. On the other hand, since the cooling coil may stop instantaneously when the air supply temperature is satisfied, determining that the cooling coil does not operate may cause an algorithmic error. In this case, it is determined whether the air supply temperature is higher than the air supply set temperature and diagnosed as a failure of the cooling coil when both conditions are satisfied.

Subsequently, the central control unit 400 checks the failure of the mixed air temperature. In mode 4, Equation 30 is used to diagnose the failure of T _ma- . In summer conditions, the outside temperature is higher than the air temperature inside the air conditioning system. However, in the case of the mixed air temperature, if it includes a specific value (ε _{ma, summer} ), it may be formed higher than the outside temperature. Even if the specific value is sufficiently large, the fault having the direction of T _ma -if the expression (30) is satisfied. You can judge.

Where T _ma is the mixed air temperature, T _OA is the outside air temperature, and ε _{ma, summer} is the allowable value due to the temperature measurement error.

Subsequently, the central controller 400 may compare the actual mixed air temperature with the reference mixed air temperature to determine the directionality at the time of the failure of the circulating air temperature T _RA . Using Equation 31, the actual mixed air temperature is higher than the standard mixed air temperature in which outside air and ventilation are mixed. In mode 4, ventilation is the majority. Since T _OA is already determined to be a normal state, it can be seen that the value of the reference mixed air temperature by T _RA is a problem. Therefore, in order to satisfy Equation 31, a fault having a directionality of T _RA -must occur. If the actual air mixture temperature not satisfy the equation 31] T _RA - failure can determine a failure of the _RA + T using the equation 32] as not.

는 기준 혼합공기온도이다. here,

Is the reference mixed air temperature.

Mode 4 operation condition has an operation condition that continuously cools only the outside air introduced into the room and supplies it to the room without introducing the outside air into the air conditioner system. If the failure of the circulating air temperature is not diagnosed, the mixed air temperature (T _ma +) failure can be diagnosed by comparing the mixed air temperature and the ventilation temperature as shown in [Equation 33]. If it reaches this stage, it is possible to detect and diagnose the failure of T _OA , T _RA and T _ma , including directionality.

T _SA failure is determined using Equations 34 and 35. In mode 4, the mixed air temperature passing through the air conditioning system is lowered through the cooling coil to form the air supply temperature. In general, since T _SA is significantly smaller than T _ma , it is difficult to diagnose a failure by comparing the supply air temperature with the mixed air temperature. To do this, set a specific value (ε _{SA, summer} ) for the air supply temperature as shown in [Equation 34], and if the sum of the air supply temperature and the specific value is lower than the mixed air temperature, the fault of the negative air supply temperature (T _SA) Judging by-).

Then, using Equation 35, a failure having a positive direction T _SA + of the air supply temperature can be detected. If the value of T _{SA indicates} a value larger than T _RA and T _ma at the same time, it can be judged as a failure of the air supply temperature.

If the condition that does not satisfy the relational expression mentioned so far to determine the failure factor, the central control unit 400 determines that the system is operating normally, and moves back to the first data collection process.

On the other hand, within the plurality of modes described above, it is determined whether or not each of the flow charts is fixed, and if a failure is found in a specific equation, the system operator is informed of the failure (in the drawing, the printing function on the flowchart is This corresponds to the failure diagnosis.

Although the present invention has been described in more detail with reference to the embodiments, the present invention is not necessarily limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.

As described above, according to the detailed classification rule-based fault detection and diagnosis method in the air conditioning system of the present invention, the disadvantage of the specification of the fault region by the multiple fault estimation which is the limitation of the existing APAR algorithm is overcome. In addition, it is possible to detect a single failure of a specific element in a short time and enable immediate maintenance, thereby minimizing the cost of building operation, efficiently preparing the element for aging equipment, and reducing the effort of the system operator. There is this.

In addition, detailed information on the positive (+) or negative (-) direction of the signal of the failure site can be known, which is advantageous for the system designer or the system operator's facility maintenance and operation when the system is diagnosed. In other words, the fault diagnosis method according to the present invention has the advantage of reducing energy consumption and minimizing the inconvenience of residents by determining the positive and negative faults in real time and notifying the air conditioning system manager. have. This can be used more effectively in diagnosing the failure of the HVAC system by informing the administrator of failure-related information than simply classifying a single failure factor.

In addition, according to the classification rule-based fault detection and diagnosis method and the apparatus using the method in the air conditioning system of the present invention, unlike the model-based fault detection and diagnosis method that can be applied only to a specific building or system, HVAC Cooling down buildings by measuring temperatures in specific parts of the system and installing low cost sensors. By grasping information on the operation of mechanical elements required for heating, it has the advantage that it can be applied comprehensively to the fault detection and diagnosis of medium and large buildings.

Claims (12)

A) assigning a limit value required for the diagnosis to a constant constant and collecting measured data values from the elements installed in the air conditioner system; B) determining whether an outside temperature factor is abnormal among the data values; C) determining whether the outside temperature is within a predetermined range and automatically selecting a mode corresponding to each range; And D) After reading the predetermined limit value in the selected mode, the information on the positive or negative directionality of the signal of the failure region and the signal of the failure region is determined by a plurality of failure determination formulas assigned to the mode. However, when satisfying the thermodynamic judgment equations of each part of the system and simultaneously satisfying a plurality of failure judgment equations including two or more related temperature factors, the common temperature factors included in the failure judgment equation are determined as the failure factor. Making; Single-site failure detection and diagnosis method of a detailed classification rule-based method in the air conditioning system comprising a. The method of claim 1, The data value measured by the step A is sent to the signal collector, using a moving average method to minimize the error of the failure diagnosis due to the error value that can occur according to the measurement in the air conditioning system, characterized in that A classification and rule-based method for detecting and diagnosing single site failures. The method of claim 1, When the outside temperature factor of step B is abnormal, when T _OA is the outside temperature, T _{OA .ref} is the outside reference temperature, and ε _OA is the allowable value of the outside temperature,

If it satisfies the condition is determined to be normal, if not satisfactory it is determined as a failure point detection and diagnostic method of the single-site failure of the detailed classification type rule-based method in the air conditioning system. The method of claim 1, When the determination result of the mode selection step of step C, T _OA is the outside temperature and T _OA , _{HT, set} is the outside heating coil set temperature

If it satisfies the current mode is selected as mode 1 and the single-site failure detection and diagnostic method of the detailed classification type rule-based method in the air conditioning system, characterized in that it determines whether the open air damper. 5. The method of claim 4, wherein T _SA is the air supply temperature, T _SA.set is the air supply set temperature, ε _SA is the air supply temperature tolerance value, ε _hc is the tolerance coefficient of the heating coil control signal, ε _f is related to the flow rate Is the allowable value due to the error, ε _MA is the allowable value due to the mixed air temperature measurement error, and u _hc is the normalized heating coil valve control signal, The step D, d1) In the mode 1, the external air temperature (T _OA ), the circulating air temperature (T _RA ), and the mixed air temperature (T _MA ) are selected as the temperature factors that are related to each other, and no abnormality of the T _OA occurs initially. Occation,

If satisfies the negative mixed air temperature factor is abnormal, otherwise it is determined that the negative mixed air temperature factor is normal,

Is called the outside temperature ratio,

When is the minimum allowable value of the outside temperature ratio,

If it satisfies the positive mixed air temperature factor is abnormal, otherwise determining that the positive mixed air temperature factor is normal; d2) If the formula of step d1 is not satisfied,

Is satisfied, the negative air supply temperature factor is abnormal. Otherwise, the negative air supply temperature factor is diagnosed as normal,

Determining that the positive air supply temperature factor is abnormal, otherwise determining that the positive air supply temperature factor is normal; And d3) after the abnormalities of T _OA , T _MA and T _SA are determined by d1 to d2,

If it is satisfied that there is an error in the negative circulating air temperature factor, otherwise it is determined that the negative circulating air temperature factor is normal, and when ΔT _min is set to the allowable value between the circulating air and the outside air temperature and the minimum temperature difference,

Determining that the negative circulating air temperature factor is abnormal, otherwise determining that the negative circulating air temperature factor is normal; Single-site failure detection and diagnosis method of the detailed classification type rule-based method in the air conditioning system comprising a. The method of claim 1, When the determination result of the mode selection step of step C, T _OA is the outside temperature, T _{OA, HT, set} is the outside air heating coil set temperature, and T _{OA , cool, set} is the outside air cooling coil set temperature,

When the current mode is satisfied, the current mode is selected as mode 2 and the single-part failure detection of the detailed classification type rule-based method in the air conditioning system, characterized in that the operation is performed to satisfy the conditions of the air supply temperature and the room temperature only by adjusting the opening degree of the external air damper. And diagnostic methods. The method of claim 6, wherein T _SA is the air supply temperature, T _RA is the circulating air temperature, ε _t is the tolerance value due to the temperature measurement error, ε _SA is the air supply temperature tolerance value, ε _MA is due to the mixed air temperature measurement error Allowable value, T _MA is the mixed air temperature,

Is the reference mixed air temperature, The step D, d1) when no abnormality of T _OA occurs initially in Mode 2,

If there is a failure that has a negative directionality in the mixed air temperature, otherwise determining that the mixed air temperature is normal; d2)

If it satisfies the fault has a negative directionality in the circulating air temperature, otherwise it is determined that the circulating air temperature is normal,

If there is a failure having a positive directionality in the circulating air temperature, if not the step of determining that the circulating air temperature is normal; d3)

If there is a failure that has a positive directionality in the mixed air temperature, otherwise, determining that the mixed air temperature is normal; d4)

If it is satisfied that there is a fault having a negative direction to the air supply temperature, otherwise it is determined that the air supply temperature is a failure,

If it satisfies the fault having a positive direction to the air supply temperature, otherwise determining that the air supply temperature is normal; Single-site failure detection and diagnosis method of the detailed classification type rule-based method in the air conditioning system comprising a. The method of claim 1, As a result of judging by the mode selection step of step C, when T _OA is the outside temperature, T _{OA , cool, set} is the outside air cooling coil set temperature, and T _{OA , cool, min, set} is the outside air cooling coil minimum set temperature,

If the current mode is satisfied, the mode is selected as mode 3, and the air damper is opened 100% and the air conditioner is operated to satisfy the rapid temperature conditions only by adjusting the cooling coil. Method for detecting and diagnosing single site failures. The method of claim 8, wherein T _OA is the outside temperature, T _SA is the air supply temperature, T _SA.set is the air supply set temperature, ΔT _SF is the temperature rise through the air supply blower, ε _t is allowed by the temperature measurement error Value, ε _SA is the supply air temperature tolerance value, T _CO is the conversion temperature changing from mode 3 to mode 4, T _MA is the mixed air temperature, T _RA is the circulating air temperature, u _CC is the normalized cooling coil valve Ε _CC is the allowable coefficient of the cooling coil control signal, The step D, d1)

If the formula of the three commonly satisfied by outside temperature (T _OA) which is fixed to the printing, or if the outside temperature are also determining that the normal factor; d2) determining that the supply air temperature is normal when T _SA -T _{SA, set} > ε _SA is satisfied; d3) If the outside temperature (T _OA ) is normal,

Determining that the conversion temperature is normal when the conversion temperature T _CO changing from the mode 3 to the mode 4 is not satisfied; d4) After diagnosing T _OA and T _CO and T _SA for abnormalities,

Determining that there is a failure in the mixed air temperature (T _MA ), otherwise determining that the mixed air temperature is normal; d5)

Re-diagnosing whether or not the air supply temperature has failed by a method of determining that the air supply temperature is normal if there is a fault in the air supply temperature (T _SA ); d6) When the air supply temperature (T _SA ) is normal,

If it satisfies the circulating air temperature (T _RA ) has a failure, otherwise determining that the circulating air temperature is normal; And d7) after that

If it satisfies the normalized cooling coil valve control signal [0, 1] (u _CC ) has a failure, otherwise determining that the control signal is normal; Single-site failure detection and diagnosis method of the detailed classification type rule-based method in the air conditioning system comprising a. The method of claim 1, As a result of the determination by the mode selection step of step C, when T _OA is the outside temperature and T _{OA , cool, min, set} is the minimum set temperature of the air cooling coil,

If the current mode is satisfied, the current mode is selected as mode 4, and the open air damper is 100% closed to block the inflow of outside air and operate to satisfy the air supply temperature condition only by adjusting the cooling coil. A classification and rule-based method for detecting and diagnosing single site failures. _11. The method of claim 10, wherein T _OA is the outside air temperature, T _SA is the air supply temperature, T _SA.set is the air supply set temperature, ε _SA is the air supply temperature tolerance value, ΔT _SF is the temperature rise through the air supply blower, ε _t is the allowable value due to temperature measurement error, T _CO is the conversion temperature changing from mode 3 to mode 4, T _MA is the mixed air temperature, T _RA is the circulating air temperature, u _CC is the normalized cooling coil valve Ε _CC is the allowable coefficient of the cooling coil control signal, ΔT _min is the allowable value between the circulating air and the outside temperature and the minimum temperature difference, ε _f is the allowable value due to the error related to the flow rate, and ε _{MA, summer} is the temperature measurement Tolerance due to error, ε _{SA, summer} is Is a specific value set for the supply air temperature,

Is the reference mixed air temperature, The step D, d1) If the signal of outside temperature (T _OA ) is normal,

Determining that the conversion temperature is normal when the conversion temperature T _CO changing from the mode 3 to the mode 4 is not satisfied; d2)

If it satisfies the fault has a negative directionality in the mixed air temperature, otherwise determining that the mixed air temperature is normal; d3) By comparing the actual mixed air temperature with the reference mixed air temperature, determine the directionality in case of failure of circulating air temperature (T _RA ),

If it satisfies the fault has a negative directionality in the circulating air temperature, otherwise it is determined that the circulating air temperature is normal,

If there is a failure having a negative directionality in the circulating air temperature, if not the step of determining that the circulating air temperature is normal; d4) If the failure of the circulating air temperature is not diagnosed, compare the mixed air temperature with the ventilation temperature,

If it satisfies the fault having a positive directionality in the mixed air temperature, otherwise determining that the mixed air temperature is normal; d5)

If it is satisfied that there is a fault in the negative air supply temperature, otherwise it is determined that the air supply temperature is normal,

If it satisfies the fault having a positive direction to the air supply temperature, otherwise determining that the air supply temperature is normal; Single-site failure detection and diagnosis method of the detailed classification type rule-based method in the air conditioning system comprising a. The method according to any one of claims 2 to 11, wherein In the air conditioning system, if the abnormality is found in a specific equation sequentially in the corresponding mode, and the abnormality is found in a specific formula, the system operator is notified of the found factor and the additional failure diagnosis in each mode is stopped. A method for detecting and diagnosing single-site failures in a detailed classification rule-based approach.

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