JP6529380B2 - Condenser diagnostic method - Google Patents

Description

  The present invention relates to a condenser diagnosis method for diagnosing a deterioration state of a condenser.

As a method for diagnosing an abnormality in the operating state of a nuclear power plant or the like, there is, for example, the invention described in Patent Document 1.
In the invention according to the document, “When the state of the device changes from a normal steady state, the coefficient is used as a steady state variable in the approximation formula for the increment of the variable obtained by differentiating the relational expression representing the normal steady state. If the amount of fluctuation is large, use the average value of the coefficients before and after the fluctuation to reduce the error. In these equations, the amount of fluctuation from the steady-state value of the measurement point variable Is used to calculate the amount of fluctuation of the variable at another measurement point, and by comparing it with the amount of fluctuation of the measured value at that point, to identify the portion in which the function is abnormal, and further to relate to that portion By substituting the fluctuation amounts of variables of all measurement points into the relational expression and calculating the fluctuation amounts of variables of abnormal points, the abnormal points included in the portion are estimated. "

Patent No. 3359109 specification

However, in the invention described in Patent Document 1, there is a possibility that the operation load becomes very large in order to identify a relational expression that accurately represents a diagnosis target such as a nuclear power plant.
In view of the above-mentioned point, the present invention aims to “diagnose the deterioration state of the condenser by a new method different from the invention described in Patent Document 1.

  In the present application, in the condenser diagnosis method for diagnosing the deterioration state of the condenser, the first physical quantity actually measured in the transient state at a predetermined time (hereinafter referred to as normal time), which is measured at the refrigerant inlet of the condenser A first acquisition step of acquiring a first physical quantity based on a difference between an enthalpy and an enthalpy at a refrigerant outlet of the condenser, and a second physical quantity measured in a transient state under normal conditions, the heat exchange being performed in the condenser A second acquisition step of acquiring a second physical quantity based on a difference between the air temperature before the temperature change and the air temperature after heat exchange in the condenser, and a mathematical model relating the first physical quantity to the second physical quantity It is a mathematical expression model identification step of identifying, which is a mathematical expression model identification step of identifying the mathematical expression model using the first physical quantity and the second physical quantity, and a physical quantity corresponding to one of the first physical quantity and the second physical quantity. Positive A third acquisition step of acquiring a physical quantity (hereinafter referred to as a first diagnosis physical quantity) measured during a transient state of timing after time (hereinafter referred to as diagnosis timing), and the other of the first physical quantity and the second physical quantity A physical quantity corresponding to a physical quantity, which is a fourth acquisition process for acquiring a physical quantity (hereinafter referred to as second diagnosis physical quantity at the time of diagnosis) measured at a transition state of diagnosis timing, and a mathematical model identified in the mathematical model identification process A comparison reference physical amount determining step of determining a comparison reference physical amount obtained by substituting the first diagnosis physical amount, and a comparison step of comparing the comparison reference physical amount with the second diagnosis physical amount.

  That is, in the present invention, a mathematical expression model is identified using two types of physical quantities that are highly correlated with each other, that is, the first physical quantity and the second physical quantity. At this time, if an ARX model is used as a mathematical expression model, it is possible to reduce the calculation load at the time of mathematical expression model identification.

It is a schematic diagram of a vapor compression type refrigerator. It is process drawing which showed the process of the condenser diagnostic method which concerns on this embodiment in order of the process.

  The “invention embodiment” described below shows an example of the embodiment. That is, the invention-specifying matters and the like described in the claims are not limited to the specific configuration and the structure and the like described in the following embodiments.

First Embodiment
1. Vapor compression refrigerator (see Figure 1)
In the present embodiment, the condenser diagnosis method according to the present invention is applied to a condenser 1 used in a vapor compression type refrigerator. The heat exchanger exchanges heat between the high-temperature high-pressure gas-phase refrigerant discharged from the compressor 2 and the air (in the present embodiment, outdoor air) with the condenser 1, and condenses (liquefys) the gas-phase refrigerant. It is.

  The decompressor 3 decompresses the high-pressure liquid-phase refrigerant condensed by the condenser 1. The evaporator 4 exchanges heat between the decompressed low-pressure refrigerant and the object to be cooled (in the present embodiment, indoor air or water) to evaporate the low-pressure liquid-phase refrigerant.

  And, with the condenser diagnosis method according to the present embodiment, the deterioration state of the condenser 1 can be diagnosed. Deterioration of the condenser 1 means, for example, (a) a decrease in heat exchange capacity due to the surface of the condenser 1 becoming dirty, and (b) a heat exchange portion (core portion) of the condenser 1 being crushed or the like. Decrease in heat exchange capacity.

  The condenser diagnosis method according to the present embodiment is not a diagnosis method for clarifying the cause of deterioration, but whether the deterioration of the condenser 1 has occurred or whether the deterioration has progressed, that is, the condenser 1 is to diagnose the deterioration state.

2. Condenser Diagnosis Method FIG. 2 is a process chart showing the process of the condenser diagnosis method according to the present embodiment in the order of the processes.
<First acquisition process>
In the first acquisition step, the first physical quantity H1 actually measured in the transient state when predetermined (hereinafter referred to as normal) is acquired. The first physical quantity H1 is a physical quantity based on the difference between the enthalpy at the refrigerant inlet of the condenser 1 and the enthalpy at the refrigerant outlet of the condenser 1.

  The first physical quantity H1 according to the present embodiment is a value obtained by multiplying the value obtained by subtracting the specific enthalpy h2 at the refrigerant outlet of the condenser 1 from the specific enthalpy h1 at the refrigerant inlet of the condenser 1 by the mass flow rate Vm of the refrigerant (= It is Vm (h1-h2).

  The “transient state” means “when a preset time has elapsed since the number of revolutions of the compressor 2 exceeds a preset fluctuation range”. The normal time means, for example, (a) at the time of development test at the manufacturer, shipping test, etc., when the vapor compression type refrigerator is first installed and operated.

<Second acquisition process>
In the second acquisition step, the second physical quantity H2 actually measured at the time of the transient state in the normal state is acquired. The second physical quantity H2 is a physical quantity based on the difference between the air temperature before heat exchange in the condenser 1 and the air temperature after heat exchange in the condenser 1.

  The second physical quantity H2 according to the present embodiment is a mass flow rate Va of air to a value obtained by subtracting the air temperature T2 before heat exchange in the condenser 1 from the air temperature T1 after heat exchange in the condenser 1 And the specific heat C multiplied value (= Va · C (T1−T2)).

<Formula model identification process>
In the mathematical expression model identification step, the mathematical expression model that relates the first physical quantity H1 and the second physical quantity H2 is identified using the first physical quantity H1 and the second physical quantity H2. In the present embodiment, an ARX (Auto-Regressive eXogeneous) model is adopted as a mathematical expression model.

<Third acquisition process>
In the third acquisition step, a physical quantity corresponding to one of the first physical quantity H1 and the second physical quantity H2 (in the present embodiment, the first physical quantity H1), and a predetermined timing after the normal time (hereinafter, diagnosis timing ) (Hereinafter referred to as “the first diagnostic physical quantity Hr1.”) Obtained in the transient state.

  The diagnosis timing according to the present embodiment refers to timing every predetermined period (for example, 30 days) based on the time when the vapor compression type refrigerator is first installed and operated. That is, the diagnosis timing according to the present embodiment is a periodic timing such as 30 days from the first day when 30 days have passed from the day of first operation (hereinafter referred to as the first time). Timing.

  In addition, implementation of the 3rd acquisition process and the following 4th acquisition process-comparison process may be any of manual implementation by the manager who manages a vapor compression type refrigerator, and automatic implementation pre-programmed.

<Fourth acquisition process>
In the fourth acquisition step, the physical quantity corresponding to the other physical quantity (the second physical quantity H2 in the present embodiment) of the first physical quantity H1 and the second physical quantity H2 and measured at the transient state of the diagnosis timing (below , And the second diagnostic physical quantity Hr2).

<Comparison criteria physical quantity determination process>
In the comparison reference physical quantity determination step, a comparison reference physical quantity Hc obtained by substituting the first diagnosis physical quantity Hr1 into the mathematical expression model identified in the mathematical expression model identification step is determined.

<Comparison process>
In the comparison step, the comparison reference physical quantity Hc and the second diagnosis physical quantity Hr2 are compared. In the comparison step, for example, the following formula 1 is used. Then, the deterioration state of the condenser 1 (in the present embodiment, the degree of contamination of the condenser 1) is determined using the value (FIT) of Formula 1. The relationship between the value (FIT) of Equation 1 and the numerical value indicating the deterioration state of the condenser 1 is associated in advance by a test and is made into a database.

３．本実施形態に係る凝縮器診断方法の特徴
本実施形態では、互いに関係性の高い２種類の物理量、つまり第１物理量Ｈ１及び第２物理量Ｈ２を用いて数式モデルを同定する。このとき、数式モデルとしてＡＲＸモデルを採用しているので、数式モデル同定時の演算負荷を低減することが可能となり得る。

3. Characteristics of Condenser Diagnosis Method According to this Embodiment In this embodiment, a mathematical expression model is identified using two types of physical quantities that are highly related to each other, that is, the first physical quantity H1 and the second physical quantity H2. At this time, since the ARX model is adopted as the mathematical expression model, it is possible to reduce the operation load at the time of identification of the mathematical expression model.

  Therefore, the deterioration diagnosis accuracy of the condenser 1 can be improved. Furthermore, since abnormalities in the vapor compression type refrigerator (for example, air conditioners) can be quantitatively diagnosed, it is possible to reduce post-maintenance work and reduce unnecessary equipment maintenance (for example, replacement of the condenser 1). it can.

(Other embodiments)
In the above embodiment, the transient state is adopted as "when the preset time has elapsed from the time when the number of revolutions of the compressor exceeds the preset fluctuation range", but the present invention is limited thereto For example, “immediately after startup of the compressor” may be set as a transient state.

  In the above-mentioned embodiment, although the ARX model was adopted as a formula model, the present invention is not limited to this. Similarly, the equation used in the comparison step is not limited to the above equation.

  In the above embodiment, “surface contamination of the condenser” is mainly assumed as “deterioration of the condenser”, but the present invention is not limited to this, for example, the airtightness / liquid tightness of the condenser The decrease in condensation capacity due to the decrease in H may be regarded as “deterioration of the condenser”.

  In the above embodiment, the first physical quantity H1 is the first diagnostic physical quantity Hr1, and the second physical quantity H2 is the second diagnostic physical quantity Hr2. However, the present invention is not limited to this, and the first physical quantity H1 is not limited thereto. Alternatively, the second diagnosis physical quantity Hr2 may be used as the second diagnosis physical quantity Hr2, and the second physical quantity H2 may be used as the first diagnosis physical quantity Hr1.

  The present invention does not have to be limited to the above-described embodiment as long as it conforms to the spirit of the invention described in the claims. That is, the condenser 1 according to the above-described embodiment may be, for example, any of an air cooling type and a water cooling type. Moreover, the use of the said condenser 1 is unquestioned.

DESCRIPTION OF SYMBOLS 1 ... Condenser 2 ... Compressor 3 ... Decompression device 4 ... Evaporator

Claims (3)

In a condenser diagnostic method for diagnosing a deterioration state of a condenser,
A first physical quantity measured during a transient state at a predetermined time (hereinafter referred to as normal), which is based on the difference between the enthalpy at the refrigerant inlet of the condenser and the enthalpy at the refrigerant outlet of the condenser 1) a first acquisition process for acquiring one physical quantity;
The second physical quantity based on the difference between the air temperature before heat exchange in the condenser and the air temperature after heat exchange in the condenser, which is the second physical quantity actually measured in the transient state at the normal time A second acquisition process for acquiring
A mathematical expression model identification step of identifying a mathematical expression model that relates the first physical quantity and the second physical quantity, wherein the mathematical expression model identification process identifies the mathematical expression model using the first physical quantity and the second physical quantity;
A physical quantity corresponding to one physical quantity among the first physical quantity and the second physical quantity, and the physical quantity (hereinafter referred to as first diagnosis) measured in the transient state of timing after the normal time (hereinafter referred to as diagnosis timing). A third acquisition step of acquiring a physical quantity);
A physical quantity corresponding to the other physical quantity among the first physical quantity and the second physical quantity, and a fourth acquisition step of acquiring a physical quantity (hereinafter referred to as a second physical quantity at diagnosis) measured at a transition state of the diagnosis timing When,
A comparison reference physical amount determination step of determining a comparison reference physical amount obtained by substituting the first diagnosis physical amount into the equation model identified in the equation model identification step;
A condenser diagnostic method comprising: a comparison step of comparing the comparison reference physical quantity with the second diagnosis physical quantity.   The condenser diagnostic method according to claim 1, wherein the transient state is "when a preset time has elapsed from the time when the number of revolutions of the compressor exceeds a preset fluctuation range". .   The condenser diagnostic method according to claim 1, wherein the mathematical model is an ARX model.

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