JP4301085B2 - Deterioration diagnosis system for heat source equipment - Google Patents

Description

  The present invention relates to a heat source device such as a turbo chiller or an absorption chiller / heater in which cooling water is passed through a condenser and a deterioration diagnosis system thereof, and more particularly to a deterioration diagnosis of a heat source device that diagnoses performance deterioration due to dirt on a heat transfer tube. It is about the system.

  Conventionally, as an abnormality detection device for detecting an abnormality of a condenser of an absorption chiller / heater that is one of heat source devices, a circuit for calculating an average temperature difference of the condenser, and a circuit for calculating a heat exchange amount of the condenser Some have an arithmetic unit including a circuit for calculating the degree of abnormality of the condenser and a failure determination circuit (see, for example, Patent Document 1).

  In this prior art, in the condenser average temperature difference calculation circuit, the cooling water intermediate temperature obtained from the cooling water intermediate temperature sensor, that is, the cooling water inlet temperature Tco_mid of the condenser, and the cooling water of the condenser obtained from the cooling water outlet temperature sensor. The average temperature difference Tm of the condenser is calculated from the outlet temperature Tco_out and the condensed refrigerant temperature Tv_cond obtained from the condensed refrigerant temperature sensor by the following calculation formula.

Tm = {(Tv_cond−Tco_mid) + (Tv_cond−Tco_out)} / 2
In the condenser heat exchange amount calculation circuit, the cooling water intermediate temperature obtained from the cooling water intermediate temperature sensor, that is, the cooling water inlet temperature Tco_mid of the condenser, and the cooling water outlet temperature Tco_out of the condenser obtained from the cooling water outlet temperature sensor. From the cooling water flow rate Vco obtained from the cooling water flow rate sensor, the condenser heat exchange amount Qcond is calculated by the following formula.

Qcond = Vco × (Tco_out−Tco_mid)
Further, in the condenser abnormality degree calculation circuit, based on the actual condenser average temperature difference Tm obtained from the condenser average temperature difference calculation circuit and the condenser heat exchange amount Qcond obtained from the condenser heat exchange amount calculation circuit, The condenser abnormality Acond is calculated by the following equation.

Acond = (Tm−Tmn) / Tmn
Here, Tmn is an ideal average temperature difference during normal operation, and is previously graphed or tabled in relation to the condenser heat exchange amount Qcond and stored in the memory.

  Further, the condenser abnormality degree obtained from the condenser abnormality degree calculation circuit is supplied to the failure determination circuit and compared with a predetermined evaluation standard. Then, the failure determination circuit determines the degree of failure based on the comparison result and outputs the result to the display device.

Japanese Patent No. 3054554

  In the conventional heat source equipment diagnosis system, as described in Patent Document 1, the degree of failure is determined based on the degree of abnormality calculated from the measured values from the sensors installed in the heat source machine. In this case, the average temperature difference of the condenser, which is the basis of the degree of abnormality, varies depending on the amount of heat exchange of the condenser as described in Patent Document 1 above, so normalization using normal values is performed. However, the degree of abnormality is affected by the heat exchange amount of the condenser, and there is a problem that even if the degree of deterioration is the same, the value varies depending on the amount of heat exchange of the condenser. It was.

  In the above prior art, an ideal average temperature difference during normal operation is used as a reference value for diagnosis, but this standard depends on the definition and calculation method during normal operation. There was a problem that it was difficult to handle due to the large influence of factors other than deterioration. In particular, the procedure for associating with heat transfer tube contamination, which is the main cause of deterioration, is complicated and unclear.

  Furthermore, in the above-mentioned prior art, an ideal average temperature difference that is a reference value is stored in relation to the amount of heat exchange of the condenser, and a cooling water variable flow rate system is introduced that controls the flow rate of cooling water to save energy. The case is not considered. In this case, when the flow rate of the cooling water is decreased, the cooling water flow rate in the heat transfer tube and the heat transfer coefficient in the tube are decreased, and thus there is a problem that the degree of abnormality increases despite being normal.

Furthermore, in the above-described conventional technology, the connection form between the heat source device main body and the abnormality detection device is not mentioned, but this point is important when industrially used and operated.
The object of the present invention is to solve the above-mentioned problems, to cope with a system in which the heat exchange amount of the condenser, the difference in the model, and the flow rate of the cooling water fluctuate, and the usability that directly copes with the contamination of the heat transfer tube which is the main cause of deterioration. It is an object of the present invention to provide a deterioration diagnosis system for a heat source device having a good evaluation index and a method for calculating the same, and a practical operational form of this system that is easy to use in industry.

  In order to achieve the above object, in the heat source equipment deterioration diagnosis system according to the present invention, in addition to the measured values from each sensor as basic data for diagnosis, the heat transfer area of the condenser, the flow passage cross-sectional area of the cooling water, etc. By using the shape data of the equipment, the diagnosis is performed by calculating the deterioration diagnosis index directly related to the deterioration phenomenon such as heat transfer rate, heat transfer coefficient in the pipe, dirt coefficient, etc. The transmission rate is also taken into consideration. In addition, a monitoring center that performs diagnosis is connected to a plurality of heat source devices via an information communication network.

  The present invention makes it possible to perform deterioration diagnosis using the heat transfer rate of the condenser, which is a physical quantity directly related to the actual deterioration, the heat transfer coefficient in the pipe, and the contamination coefficient, and the correlation with the deterioration in the performance of the entire heat source device becomes clear. . For example, it is possible to easily predict how much the performance will recover when the dirt is removed by cleaning the heat transfer tubes, setting the time and contents of maintenance including cleaning of the heat transfer tubes appropriately, systematically, It can be done economically.

  Furthermore, according to the present invention, even when the flow rate of the cooling water flowing through the condenser of the heat source device fluctuates, the contamination coefficient of the heat transfer tube is calculated by eliminating this effect. Even when introduced, a suitable deterioration diagnosis system can be obtained. Furthermore, the deterioration diagnosis system can be efficiently operated by centrally managing a plurality of heat source devices by using the information communication network.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall view of a deterioration diagnosis system for heat source equipment according to the present invention. FIG. 2 is a diagram showing the measurement system of the heat source equipment portion of the deterioration diagnosis system according to the present invention for each of the steam soak absorption type refrigerator (a) and the turbo refrigerator (b). Further, FIG. 3 is a block diagram of a diagnostic apparatus of the degradation diagnostic system according to the present invention.

  As shown in FIG. 1, the deterioration diagnosis system includes a heat source unit 1, a heat source unit 2,..., A data recording unit 1a, 2a,. na, an information communication network 100 connected to these data recording units, and a deterioration diagnosis apparatus 200 connected to the information communication network 100.

  FIG. 2 (a) shows a connection diagram of signal lines between the heat source unit main body and the data recording unit when the heat source unit is a steam tank absorption chiller / heater. The absorption chiller / heater includes general high-temperature regenerator 31, low-temperature regenerator 32, condenser 33, evaporator 34, absorber 35, low-temperature heat exchanger 36, high-temperature heat exchanger 37, drain cooler 38, and the like. It is composed of In this embodiment, as a cooling water flow method, the cooling water is first passed through a part of the absorber 35, and then is passed through the condenser and then through the remaining part of the absorber. .

  In the data recording unit 1a, as measured values for detecting contamination of the heat transfer tube, the cooling water inlet temperature 33a to the condenser, the cooling water outlet temperature 33b from the condenser, the refrigerant vapor pressure 33c in the condenser, the condensation The measurement signal of the flow rate 33d of the cooling water that is passed through the absorber and the absorber is input. In addition, as measured values for diagnosing the performance of the entire heat source machine, the temperature 35a of cooling water supplied to the absorption chiller / hot water machine, the temperature 35b of cooling water sent from the absorption chiller / heater to a cooling tower (not shown), an evaporator The cold water inlet temperature 34a, the cold water outlet temperature 34b, the cold water flow rate 34d, the inlet pressure 31a of the heat source steam supplied to the high temperature regenerator 31, the drain temperature 31b from the high temperature regenerator to the drain cooler 38, the drain flow rate 38d, etc. are input. , Remembered.

  Next, FIG. 2B shows a connection diagram of signal lines between the heat source unit main body and the data recording unit when the heat source unit is a turbo refrigerator. The turbo refrigerator includes a compressor 71, a condenser 33, an evaporator, and the like, and a data recording unit 2a is installed. The cooling water is supplied to the condenser from the cooling water inlet pipe 82 and is discharged from the condenser through the cooling water outlet pipe 81.

  In the data recording unit 2a, as measured values for detecting contamination of the heat transfer tube, the cooling water inlet temperature 33a to the condenser, the cooling water outlet temperature 33b from the condenser, the refrigerant vapor pressure 33c in the condenser, the condensation The measurement signal of the cooling water flow rate 33d passed through the vessel is input.

  The measured values of these heat source machines are transmitted to the deterioration diagnosis apparatus 200 shown in FIG. The deterioration diagnosis apparatus 200 includes a calculation unit 210, a storage unit 250, a display unit 290, and the like, and the storage unit 250 stores a heat source machine specification database 251 (stores various specification data such as shape data and heat transfer characteristics). A deterioration history database 261 is stored. FIG. 3 is a block diagram showing calculation contents in the calculation unit 210. Hereinafter, taking the heat source device 1 as an example, a method for diagnosing deterioration of heat transfer tube contamination in the calculation unit 210 will be described in detail.

  In the calculation unit 200, the condenser cooling water inlet temperature TwCi, the condenser cooling water outlet temperature TwCo, the condenser pressure pC, and the condenser which are transmitted from the data recording unit 1a provided in the heat source device 1 via the information communication network 100. Equipment data such as the cooling water flow rate GwC, the condenser heat transfer area AC, the condensation heat transfer coefficient αCo, and the condenser cooling water flow path cross-sectional area SwC stored in the heat source unit specification database 251 of the storage unit 250 in FIG. Based on the physical properties of the cooling water, the deterioration of the heat transfer tube dirt is diagnosed by the following procedure.

  First, the refrigerant condensing temperature TC is calculated from the condenser pressure pC by the formula 1 of the thermophysical value of the refrigerant used in the heat source unit 1.

  The function ft of Equation 1 is determined by the type of refrigerant. For example, for an absorption chiller using water as a refrigerant, the relational expression between the water vapor pressure and the equilibrium temperature described in the steam table or the like is used.

  Next, the average heat exchange temperature difference ΔTC of the condenser is obtained by Equation 2 from the TC calculated by Equation 1, the condenser cooling water inlet temperature TwCi, and the condenser cooling water outlet temperature TwCo.

  The logarithmic average temperature difference ΔLTC may be obtained by the following equation (3).

  Next, the condenser exchange heat quantity QC is calculated by the following equation 4 from the condenser cooling water inlet temperature TwCi, the condenser cooling water outlet temperature TwCo, and the condenser cooling water flow rate GwC.

  Here, cpwC is the specific heat capacity of the cooling water, and is stored in the heat source unit specification database 251 in the storage unit 250 as a constant value. Note that this specific heat capacity may be calculated from the condenser cooling water inlet temperature TwCi, the condenser cooling water outlet temperature TwCo, or an average value of these, using Equation 5 representing the physical property value of water.

  Equation 5 is a function for obtaining the specific heat capacity of cooling water, that is, water from the temperature.

  The above calculation procedure is the same as that described in Patent Document 1. In the present embodiment, the average heat exchange temperature difference ΔTC of the condenser calculated by Equation 2, the condenser exchange heat quantity QC calculated by Equation 4, and the condenser heat transfer area AC stored in the heat source unit specification database 251 The condenser heat passage rate KC is obtained by the following equation (6).

  The condenser heat transfer area AC may be the area outside or inside the heat transfer tube when a tube group type condenser is used. In this embodiment, the area outside the tube is used, and the total area outside the tube of the heat transfer tube group of the condenser is represented by ACo.

  Next, the condenser heat passage rate KC calculated in Equation 6, the condensation heat transfer coefficient αCo stored in the heat source unit specification database 251, the total outside area of the condenser heat transfer tube group from ACi, and the condenser tube heat The transmission rate αCi is obtained by the following equation (7).

  Next, it shifts to the calculation of the fouling coefficient of the heat transfer tube. First, the condenser cooling water pipe flow velocity vwC is obtained from the condenser cooling water flow rate GwC and the condenser cooling water flow passage sectional area SwC stored in the heat source device specification database 251 by the following equation (8).

  Here, ρwC is the density of the cooling water, and is stored in the storage unit 250 as a constant value. Note that this density may be calculated from the condenser cooling water inlet temperature TwCi, the condenser cooling water outlet temperature TwCo, or an average value of these using Equation 9 representing the physical property value of water.

  Equation 9 is a function for determining the density of the cooling water, that is, the water from the temperature.

  Next, using the condenser cooling water pipe flow velocity vwC calculated in Expression 8 and the condenser cooling water heat transfer pipe inner diameter dCi stored in the heat source machine specification database 251, the condenser ideal pipe heat transfer coefficient αCii is expressed as Determined by 10.

  In Equation 10, NuwC is the average Nusselt number of the cooling water flowing in the condenser tube, and is obtained from the condenser cooling water tube flow velocity vwC by a commonly used Ditasuerbelter equation in this embodiment. Further, λwC is the thermal conductivity of the cooling water, and is obtained from the temperature of the cooling water using the physical property formula.

  Further, the condenser pipe fouling coefficient rCi is calculated by the following expression 11 from the condenser pipe heat transfer coefficient αCi calculated by Expression 7 and the condenser ideal pipe heat transfer coefficient αCii calculated by Expression 10.

  In the storage unit 250 of the diagnostic apparatus 200, the condenser tube contamination coefficient rCi calculated by Equation 10, the condenser tube heat transfer coefficient αCi calculated by Equation 7, and the condenser heat passage rate KC calculated by Equation 6 are stored. The deterioration history database 261 is stored over time.

  These values are stored as average values for each month, and are displayed as numerical values or as a trend display as shown by 299 in FIG. 1 by operating the display unit 290 of the diagnostic apparatus 200. Diagnosis is performed using this display result.

  In addition, time series data as shown in trend display example 299 is approximated by a function such as a linear expression to predict the progress of subsequent deterioration, and based on the result, heat transfer tube cleaning, cooling water quality management, etc. You can also plan for maintenance.

  The above description describes deterioration judgment by solving the mathematical formula, and this will be described with reference to FIG.

First, the refrigerant condensing temperature TC is obtained by Equation 1 using the measured condenser pressure 33c. Next, the condenser heat exchange temperature difference ΔTC is obtained by Equation 2 using the measured values of the condenser cooling water inlet temperature 33a and the condenser cooling water outlet temperature 33b and the refrigerant condensation temperature TC. Further, the condenser exchange heat quantity QC is obtained by Equation 4 using the condenser cooling water inlet temperature 33a, the condenser cooling water outlet temperature 33b, and the cooling water flow rate 33d. Next, the condenser heat passage rate KC is obtained by Equation 6 using the condenser heat exchange temperature difference ΔTC, the condenser exchange heat quantity QC, and the condenser heat transfer area AC. Further, the heat transfer coefficient αC _i in the condenser tube is obtained by Equation 7 using the condensation heat transfer coefficient αC _{0 and the} like and the condenser heat transfer coefficient KC.

  Next, the condenser cooling water pipe flow velocity vwC is obtained by the following equation (8) from the cooling water flow rate 33d and the condenser cooling water flow path sectional area SwC. From the condenser cooling water pipe flow velocity vwC and a condenser cooling water heat transfer pipe inner diameter dCi (not shown in the figure), an ideal heat transfer coefficient αCii in the condenser pipe is obtained by Equation (10). Next, the condenser pipe fouling coefficient rCi is obtained by Equation 11 using the condenser pipe heat transfer coefficient αCi and the condenser pipe ideal heat transfer coefficient αCii. Then, the deterioration coefficient database 261 stores the condenser pipe contamination coefficient, the condenser pipe heat transfer coefficient, and the condenser heat passage ratio in time series, and the results are displayed on the display section in time series. In addition, it is determined whether or not the condenser coefficient in the condenser tube exceeds a predetermined reference value (tube contamination diagnosis), and if it exceeds the reference value, a notification is made to perform cleaning or the like in the tube. Further, the degree of change in the condenser coefficient in the condenser tube is obtained, the progress of deterioration is predicted, and a maintenance plan or the like can be drawn up.

  As described above, in the present embodiment, the actual phenomenon is directly reflected on the heat transfer pipe contamination of the cooling water system, which is a representative factor of the deterioration of the heat source equipment, and there is a relationship with the performance deterioration of the heat source apparatus. Diagnosis is made using the obvious fouling coefficient rCi in the condenser tube and heat transfer coefficient αCi in the condenser pipe. Compared with the conventional technology that diagnoses from the heat exchange temperature difference and the heat exchange amount, the diagnosis result and the performance of the heat source machine It is possible to easily and accurately predict the relationship with deterioration and the performance recovery effect during heat transfer tube cleaning.

  Furthermore, in the present embodiment, the heat source unit specification database 251 is provided in the storage unit 250 of the diagnostic apparatus 200. Therefore, for each type of various heat source units, the condenser heat passage rate KC, condensation from the shape data of the model. The heat transfer coefficient αCi in the pipe and the contamination coefficient rCi in the condenser pipe can be calculated.

  Furthermore, in the present embodiment, the cooling water flow rate 33d is actually measured using a flow meter, so even when the cooling water flow rate during operation is different from the rated flow rate of the heat source unit or when a cooling water variable flow rate system is adopted. It is possible to perform diagnosis by calculating the condenser exchange heat quantity QC and the condenser pipe flow velocity vwC from the actually measured values.

  Further, in the present embodiment, since the plurality of heat source devices 1, 2,... N and the diagnostic device 200 are connected by the information communication network 100, the data management can be performed centrally and easily. By providing the specification database in the diagnostic apparatus 200, it is possible to prevent leakage of confidential data related to the internal shape of the heat source machine.

1 is an overall view of a deterioration diagnosis system for a heat source device according to the present invention. It is a measurement system diagram of the heat-source equipment part of the deterioration diagnosis system by this invention. It is a block diagram of the diagnostic apparatus of the degradation diagnostic system by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat source machine (steam smoke absorption type refrigerator), 2 ... Heat source machine (turbo refrigerator), 3, 4, ..., n ... Heat source machine, 1a, 2a, ..., na ... Data recording part, 31 ... High temperature regenerator, 32 ... low temperature regenerator, 33 ... condenser, 34 ... evaporator, 35 ... absorber, 36 ... low temperature heat exchanger, 37 ... high temperature heat exchanger, 38 ... drain cooler, 71 ... compressor, 81 ... Cooling water inlet piping, 82 ... cooling water outlet piping, 100 ... information communication network, 200 ... deterioration diagnosis device, 210 ... calculation unit, 250 ... storage unit, 251 ... heat source machine specification database, 261 ... heat source machine deterioration history database, 290 Display unit, 299 ... Display example, 31a ... Heat source steam pressure, 31b ... High temperature regenerator heat source drain outlet temperature, 33a ... Condenser cooling water inlet temperature, 33b ... Condenser cooling water outlet temperature, 33c ... Condenser pressure, 33d ... Condenser cooling water 34a ... Evaporator (heat source machine) cold water inlet temperature, 34b ... Evaporator (heat source machine) cold water outlet temperature, 34d ... Cold water flow rate, 35a ... Heat source machine cooling water inlet temperature, 35b ... Heat source machine cooling water outlet temperature, 38b ... Drain cooler drain outlet temperature, 38d ... Drain flow rate.

Claims (3)

In a deterioration diagnosis system for a heat source device for detecting contamination of a heat transfer tube of a heat source device to which cooling water is supplied from the outside, a cooling water inlet temperature detection means for a condenser through which the cooling water of the heat source device is passed, and A cooling water outlet temperature detecting means for the condenser, a refrigerant condensing temperature detecting means for the condenser, and a deterioration diagnosis device for detecting dirt in the heat transfer tube of the condenser, wherein the deterioration diagnosis device includes the condenser A storage unit that stores the shape data of the condenser, and the condenser cooling water inlet temperature, the condenser cooling water outlet temperature, the refrigerant condensing temperature detected by each of the detecting means, and the shape data stored in the storage unit A heat transfer rate calculating means for calculating the heat transfer rate of the vessel ,
The cooling water flow rate detecting means of the condenser is provided, and the heat passage rate calculating means of the deterioration diagnosis device is such that the cooling water inlet temperature of the condenser, the cooling water outlet temperature of the condenser detected by each of the detecting means, and the refrigerant Calculate the heat transfer rate of the condenser from the condensation temperature, the cooling water flow rate and the shape data stored in the storage unit,
The deterioration diagnosis device stores the condensation heat transfer coefficient in the storage part, and also calculates the condenser from the heat transfer rate calculated by the heat transfer rate calculation means, the shape data of the condenser, and the condensation heat transfer rate. The heat transfer coefficient calculation means for calculating the heat transfer coefficient in the pipe, the cooling water inlet temperature of the condenser or the cooling water outlet temperature of the condenser detected by each of the detection means, the cooling water flow rate, and the storage in the storage unit An ideal pipe heat transfer coefficient calculating means for calculating the ideal pipe heat transfer coefficient of the condenser from the obtained shape data, and a heat transfer pipe fouling coefficient of the condenser from the pipe heat transfer coefficient and the ideal pipe heat transfer coefficient. A deterioration diagnosis system for heat source equipment , comprising: a heat pipe contamination coefficient calculation means . The deterioration diagnosis system for a heat source device according to claim 1, wherein the deterioration diagnosis device has a heat passage rate storage means for storing the heat passage rate of the condenser calculated by the heat passage rate calculation means in a time series. , The heat transfer rate of the condenser, or a relative value or ratio based on the value at a predetermined time of the heat transfer rate of the condenser, or the heat transfer rate of the condenser, which is a part of the shape data. A deterioration diagnosis system for heat source equipment, comprising a display unit for displaying a value obtained by multiplying a heat area. The deterioration diagnosis system for a heat source device according to claim 1, wherein the deterioration diagnosis device has a fouling coefficient storage means for storing the heat transfer pipe fouling coefficient of the condenser calculated by the heat transfer pipe fouling coefficient calculation means in a time series. And a deterioration diagnosis system for a heat source device, comprising a display unit for displaying a relative value of a condenser fouling coefficient or a value of a condenser fouling coefficient at a predetermined time as a reference.

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