JP4290705B2 - Diagnostic method and diagnostic system for air conditioner - Google Patents

Description

  The present invention relates to an air conditioner diagnosis method and diagnosis system, and more particularly to an air conditioner diagnosis system and diagnosis method suitable for remotely managing a plurality of air conditioners installed in a plurality of customers.

Conventionally, a technology for monitoring limited data of air conditioners is known in a center that centrally manages the operation of air conditioners (air conditioners), but the trigger of confirmation act is artificially performed. Currently. In addition, the determination of the degree of deterioration of the air conditioner relies on the visual confirmation at the site and the empirical judgment of the confirmer based on the operating state information of the air conditioner. Furthermore, a system that centrally manages the degree of deterioration of a plurality of air conditioners has not been realized. In this regard, a system that centrally diagnoses the operating states of a plurality of air conditioners remotely via a communication network has been proposed (see, for example, Patent Document 1). However, although this technology provides information by associating failure diagnosis information with repair information, its main purpose is to improve customer service and reduce communication costs. Specific diagnosis logic for air conditioners is disclosed. It has not been.
JP 2004-86675 A

  This invention is for solving such a problem, and provides the specific logic of the performance degradation diagnosis regarding the specific site | part of an air conditioner, and the technique regarding the centralized management of several air conditioners.

The gist of the present invention is as follows. That is,
(1) A step of obtaining operation data corresponding to an explanatory variable for a specific part of the air conditioner, a step of calculating a predetermined evaluation variable related to performance deterioration of the specific part based on the explanatory variable, and the evaluation variable A method of diagnosing deterioration of an air conditioner, comprising: determining that the specific portion is deteriorated in performance when the value exceeds a predetermined threshold value.

(2) The specific part is an outdoor unit heat exchanger, and the operation data includes an outdoor unit suction temperature (T1), an outdoor unit blowing temperature (T2), a refrigerant circulation amount (Gr), a refrigerant high pressure (Pc), It includes at least one of refrigerant low pressure (Pv), refrigerant high pressure temperature (Tc) or refrigerant low pressure temperature (Tv), and expansion valve opening, and the evaluation variable is a KA value of the outdoor unit heat exchanger. And

The present invention automatically diagnoses a performance deterioration state due to corrosion, dirt, etc. of an outdoor unit heat exchanger that is assumed to have the most significant function deterioration in an air conditioner. FIG. 5 is a diagram for explaining the logic for obtaining the KA value, which is an evaluation variable, using the Moliere diagram. In the figure, the heat exchange amount (heat dissipation amount) Qc in the condenser is
Qc = Gr (h3-h1 ′) (1)
Indicated by Here, the refrigerant circulation amount Gr can be obtained, for example, by measuring the compressor frequency fc. h1 ′ is the refrigerant enthalpy in a state of being supercooled from the condensation temperature Tc corresponding to the refrigerant high pressure Pc. The supercooling temperature can be obtained from the refrigerant circulation amount and the expansion valve opening, but an average supercooling temperature of 3 to 5 ° C. may be used approximately.

Using these, the KA value is expressed by the following equation.
KA = Qc / MTD (2)
Here, MTD is a logarithm average temperature difference, and MTD = (Δ1−Δ2) / log (Δ1 / Δ2)
Indicated by Δ1 = T1-Tc, Δ2 = T2-Tc.

  Since the KA value indicates the heat transfer performance of the heat exchanger at the time of measurement, it is possible to grasp the deterioration of the heat transfer performance due to corrosion, dirt, etc. of the outdoor unit heat exchanger by continuously monitoring the KA value. . In addition, preventive maintenance is possible by threshold management based on experience values.

(3) The ratio (deterioration degree) between the KA value at the time of evaluation and the KA value at the time of a new article is used as the threshold value.
Ratio of KA value (KA (t)) after elapse of time t from the new article to KA value (KA (0)) of the new article D1 = KA (t) / KA (0) is the heat exchanger deterioration at time t It can be said that it represents a degree. Therefore, by knowing the KA (0) data of the target air conditioner in advance and obtaining the KA value at the time of diagnosis, it is possible to diagnose the degree of deterioration at that time. Further, if a threshold value is provided for the degree of deterioration D1, quantitative preventive maintenance can be performed.

(4) As a threshold value, a regression curve of the degree of deterioration using the outdoor unit suction temperature as a parameter and the high-pressure protection control operation frequency is used.
(5) In this case, the degree of deterioration at which the high-pressure protection control operation frequency becomes a desired value with respect to a predetermined outdoor unit suction temperature can be set as a threshold value .

  FIG. 5 conceptually shows the principle of the present invention. The figure shows the regression curve using the operating temperature of the outdoor unit high-pressure protection control (high-pressure cut) operation and the degree of deterioration (D1) for a specific air conditioner and using the suction temperature as a parameter. In the figure, a value of “no high pressure cut operation” is selected as the threshold value (D1th) at a suction temperature of 40 ° C. By setting the time point at which the KA value corresponding to this is reached as a warning target, it is possible to avoid troubles due to, for example, shutdown due to aging. Furthermore, the determination table can be created based on the operation data of the same model installed in a plurality of customers.

(6) The specific part is an indoor unit blower, and the explanatory variables include at least an indoor unit blower frequency (fw), an indoor unit suction temperature (T3), an indoor unit blowing temperature (T4), and a compressor frequency (fc). In any case, the evaluation variable is an indoor unit air volume reduction rate.

  The present invention enables performance diagnosis by monitoring the amount of air blown from the indoor unit blower. The present invention is premised on sensible heat air conditioning. Possible causes of a decrease in the amount of air flow include resistance in the indoor air circulation circuit, which could not be assumed by the designer, air channel blockage, filter clogging, fan belt slip, and the like.

The principle of the present invention is as follows. In FIG. 6, the heat exchange amount (heat radiation amount) Qv in the evaporator is
Qv = Gr (h2′−h1 ′) (3)
Indicated by The refrigerant circulation amount Gr can be obtained by measuring the compressor frequency as described above. h2 ′ is the refrigerant enthalpy in a state of being heated from the saturation evaporation temperature Tv corresponding to the refrigerant low pressure (Pv). As the superheating temperature, an average supercooling temperature of 3 to 5 ° C. can be used approximately.

If the indoor unit air volume is F and the specific air heat is Cp, then Qv = F · Cp · (T4-T3)
F = Gr (h2′−h1 ′) / [Cp (T4-T3)] (4)
Indicated by

  The air flow rate reduction rate (D2) is obtained by the ratio of the air flow rate F (t) after the elapse of time t from the new time and the air flow rate F (0) at the new time or the design new time D2 = F (t) / F (0) Can do. Moreover, the deterioration degree can be diagnosed by providing a threshold value in advance.

(7) An air conditioner diagnostic system comprising a management server, one or more air conditioners installed at one or more customers, and capable of communicating with each other via a communication network. The server includes means for acquiring one or a plurality of operation data of each air conditioner, means for calculating a predetermined evaluation variable related to the soundness of a specific part of each air conditioner based on the operation data, and an evaluation variable A diagnosis of an air conditioner comprising: means for determining deterioration of the specific part when a predetermined threshold value is exceeded; and means for distributing a determination result to a customer side as necessary System.

According to each said invention, it becomes possible to determine quantitatively the performance degradation (deterioration degree) accompanying aged use etc. about the specific site | part of an air conditioner.
In addition, according to the invention of outdoor unit (condenser) performance diagnosis, automatic diagnosis, remote diagnosis, periodic inspection of deterioration conditions such as corrosion and dirt of heat exchangers of outdoor units that are assumed to be the most significant deterioration of air conditioner functions Diagnosis is possible.
Moreover, according to the indoor unit (blower) performance diagnosis invention, the air volume of the indoor unit blower, which is closely related to the air conditioning function, due to a decrease in the rotation speed due to the looseness of the belt or the operation outside the design assumption of the external static pressure It is possible to perform automatic diagnosis, remote diagnosis, and periodic diagnosis of airflow reduction.
In addition, according to the invention of consolidating operation data of a plurality of air conditioners on the management server, it is possible to centrally manage a plurality of air conditioners installed in a plurality of customers, and the accuracy of deterioration diagnosis is increased because the parameter of operation data is increased. Can be improved.

  Hereinafter, each embodiment of the air-water cooling operation control method of an air conditioner according to the present invention will be described in more detail with reference to FIGS. Needless to say, the scope of the present invention is described in the claims and is not limited to the following embodiments.

(Condenser deterioration diagnosis)
FIG. 1 is a diagram showing an air conditioner diagnosis system 1 according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of the air conditioner Aj. FIG. 3 is a diagram illustrating a deterioration diagnosis flow of the condenser 21a in the air conditioner diagnosis system 1.
Referring to FIG. 1, an air conditioner diagnosis system 1 mainly includes a management center 2 that centrally manages air conditioners installed at a plurality of customers, customers C1 to Cn, and a communication network 3 that connects the management center 2 and each customer. The configuration. The management center 2 includes a server 4 having a transmission / reception unit 4a, a deterioration degree calculation unit 4b, a diagnostic report creation unit 4c, and the like, and a database 4d. The database 4d stores a customer data table, a device data table, an operation data table, a deterioration degree determination table, etc. (not shown). The operation data table stores operation data of air conditioners installed in a plurality of customers. Further, a deterioration degree determination table as shown in FIG. 4 is created in advance based on the operation data. The equipment data table stores equipment data including a KA value at the time of a new article, which will be described later, a designed indoor unit blower air volume obtained from the static pressure outside the designed machine, and the like.

  The customer Ci includes a plurality of air conditioners A1 to Am, a transmission / reception control unit 5 that transmits operation data of each air conditioner to the management center 2 via the network 3, and a personal computer (PC) 8 that receives distribution of the device diagnosis report. ing. Other customers have the same configuration. As the communication network 3, for example, an Internet line, a public telephone network, ISDN, a dedicated line, a packet switching network, or the like can be used. Data communication between the server 4 and the transmission / reception control unit 7 is performed in the XML format.

  Next, referring to FIG. 2, an air conditioner Aj includes a compressor 23, a condenser 21a, an outdoor fan 21b, an outdoor unit 21 provided with an expansion valve 21c, an indoor unit 22 provided with an evaporator 22a and an indoor fan 22b, A refrigerant pipe 24 that connects the components of the outdoor unit 21 and the indoor unit 22 is provided as a main component. The refrigerant pipe 24 is filled with a refrigerant, and is configured so that the refrigerant circulates in a gas or liquid state according to the refrigeration cycle. In addition to the above, the air conditioner Aj includes various components constituting a heat pump system such as a four-way valve and an accumulator, but the illustration is omitted.

  Next, the operation data measuring means of the air conditioner Aj is configured as follows. The outdoor unit 21 is provided with a temperature sensor for measuring the suction temperature T1 and the blowout temperature T2, and the indoor unit 22 is provided with a temperature sensor for measuring the suction temperature T3 and the blowout temperature T4. As for the refrigerant piping system, sensors for measuring the refrigerant low pressure Pv and the low pressure temperature Te are arranged in the evaporator 22a, and sensors for measuring the high pressure Pc and the high pressure temperature Tc are arranged near the outlet of the condenser 21a. Has been. The measured value of each sensor, the opening degree of the expansion valve 21c, and the like are configured to be taken into the server 4 of the management center 2 via the transmission / reception control unit 5 and the communication network 3.

  The air conditioner diagnosis system 1 is configured as described above. Next, a deterioration diagnosis flow relating to the condenser 21a performed in the management server 4 will be described with reference to FIG. With the start of the diagnostic step, operation data is collected a predetermined number of times at predetermined time intervals (step S101). The operation data includes outside air temperature, compressor frequency, indoor fan frequency, outdoor fan frequency, expansion valve opening, high pressure, low pressure, high pressure or low pressure. The fetched data is stored in a predetermined storage area of the DB 4d of the management center 2.

  Further, the following calculation is performed using the average value of the collected data. First, the refrigeration cycle is estimated (step S102). First, the condensation pressure equivalent saturation temperature Tc is estimated based on the high pressure and the high pressure. Next, an evaporation pressure equivalent saturation temperature Tv is estimated based on the low pressure and the low pressure. Further, the condensation and evaporation pressure equivalent saturation temperature is corrected in consideration of the degree of supercooling and the degree of superheat (step S103). A standard value of 3 to 5 ° C. is used as the correction value. In the correction, it is also possible to calculate based on the expansion valve opening degree and the like.

Furthermore, the amount of heat exchange accompanying condensation is estimated by the above-described equation (1) (step S104), and then KA (t), which is the KA value at the time of evaluation, is calculated using equation (2) (step). S105). Further, the calculation of the deterioration degree I = KA (t) / KA (0) is performed (step S106). In addition, the value stored in the device table is used as the KA value (KA (0)) when new. Next, it is determined whether or not the deterioration degree D1 exceeds the threshold value D1th (step S107). Here, the threshold value D1th is determined based on a high pressure protection control operation limit for a predetermined temperature by contract with a customer or the like (for example, there is no high pressure cut at a suction temperature of 40 ° C.). When the threshold value is exceeded (YES in step S108), a warning mail is sent to the customer PC for warning (step S109). When the threshold is not exceeded, the determination result is stored (step S110), and the process waits until the next determination timing.
In the present embodiment, the determination of the maximum compressor capacity is performed based on the frequency, but other forms, for example, a form for detecting the rotational speed may be employed.
In this embodiment, the central control method is used to transmit the operation data to the management center. However, an individual management method may be used by using a stand-alone computer.

(Indoor unit blower diagnosis)
Next, another embodiment of the present invention will be described. This embodiment performs performance diagnosis of an indoor unit blower on the premise of sensible heat air conditioning. Since the configurations of the diagnosis system and the air conditioner are the same as those in the first embodiment, illustration and description thereof are omitted.
FIG. 4 is a diagram illustrating a deterioration diagnosis flow of the indoor unit blower 22b. With reference to the figure, steps S201 to S204 are the same as those in the first embodiment. However, it is different from the condenser 21a in that the heat exchange amount of the evaporator 22a is different. Next, the indoor unit air volume is estimated based on the above equations (3) and (4) (step S205). Next, the ratio of the air flow rate (W) and the design air flow rate (W0) at the time of the obtained evaluation and the calculation of W / W0 are performed (step S206), and it is further determined whether or not the predetermined threshold value D2th is exceeded. (Step S207). If the threshold value is exceeded, a warning mail is sent to the customer PC for warning (step S208). If the threshold is not exceeded, the determination result is stored (step S209), and the process waits until the next determination timing.

  In the present embodiment, the sensible heat air conditioning is assumed. However, it is possible to evaluate the latent heat air conditioning by measuring the amount of dehumidification.

  The present invention can be widely applied to a compression air conditioner regardless of the heat source type, the refrigerant type, the air conditioning system, and the like.

1 is a diagram illustrating an overall configuration of an air conditioner diagnosis system 1. FIG. It is a figure which shows the structure of air conditioner Aj. It is a figure which shows the condenser degradation degree determination flow in 1st embodiment. It is a figure which shows the indoor unit air blower deterioration degree determination flow in 2nd embodiment. It is a figure which shows the principle of deterioration degree threshold value management. It is a figure which shows the principle of this invention on a Moliere diagram (ph diagram).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Air-conditioner diagnostic system 2 ... Management center 3 ... Communication network 4 ... Management server 4a ... Transmission / reception unit 4b ... Degradation degree calculation unit 4c ... Diagnosis report creation unit 4d ... Database 5 ... Transmission / reception control unit 21 ... Outdoor unit 21a ... Condenser 21b ... Outdoor blower 21c ... Expansion valve 22 ... Indoor unit 22a ... Evaporator 22b ... Indoor fan 23 ... Compressor 24 ... Refrigerant pipes A1 to Am ... Air conditioners C1 to Cn ... Customer Pv .... Refrigerant low pressure Pc ... High pressure Tv ... Low pressure temperature Tc ... High pressure temperature

Claims (1)

For a specific part of the air conditioner, obtaining operation data corresponding to the explanatory variable;
Calculating a predetermined evaluation variable related to performance degradation of the specific part based on the explanatory variable;
When the evaluation variable exceeds a predetermined threshold, and determining that the specific portion is performance degradation,
The specific part is an outdoor unit heat exchanger,
The operation data includes at least one of an outdoor unit suction temperature, an outdoor unit blowing temperature, a refrigerant circulation amount, a refrigerant high pressure, a refrigerant low pressure, a refrigerant high pressure temperature or a refrigerant low temperature, and an expansion valve opening degree,
The evaluation variable is a deterioration degree determined based on a ratio between a KA value at the time of evaluation of the outdoor unit heat exchanger and a KA value at the time of a new product,
The threshold is defined as a degree of deterioration in which the high-pressure protection control operation frequency at a predetermined outdoor unit suction temperature is a predetermined value in the regression curve of the deterioration degree and outdoor unit high-pressure protection control operation frequency using the outdoor unit suction temperature as a parameter. The
A deterioration diagnosis method for an air conditioner characterized by the above.

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