JP6900303B2 - Refrigerator performance diagnostic system - Google Patents

Description

The present invention relates to a performance diagnosis system and a performance diagnosis method for a refrigerator.

When the performance of the refrigerator deteriorates, it is necessary to promptly identify the cause and perform maintenance.

Patent Document 1 shows the actual performance under the evaluation operation condition based on the evaluation operation condition data for the purpose of accurately separating the tube cleaning and the overhaul as the maintenance contents to be performed for the performance deterioration of the refrigerator. The evaluation actual COP and the evaluation reference LTD are calculated, and the COP change amount indicating the difference between the evaluation actual COP and the evaluation standard COP and the LTD change amount indicating the difference between the evaluation actual LTD and the evaluation standard LTD are calculated. , A refrigerator deterioration diagnosis device and a refrigerator deterioration diagnosis method that classify cases according to whether or not the change amount ratio R between the COP change amount and the LTD change amount at the time of evaluation is within a certain determination region Q are disclosed. There is. Further, in Patent Document 1, when the change amount ratio R is within the constant determination area Q, tube cleaning is selected as the maintenance type when performing maintenance on the refrigerator, and the change amount ratio R is outside the determination area Q. If, it is disclosed that overhaul is selected as the maintenance type. Here, LTD is an abbreviation for Leaving Temperature Difference, which is one of the indexes indicating the performance of the refrigerator.

Japanese Unexamined Patent Publication No. 2016-205640

In the refrigerator deterioration diagnosis method described in Patent Document 1, if the cause of the change in COP is other than the dirt inside the tube, it is determined that the COP is overhauled, and it is not clear where the problem is occurring. In addition, when the judgment is overhaul, there is a possibility that parts that do not need to be replaced may be replaced, so that the repair cost may be unnecessarily expensive.

An object of the present invention is to identify the component causing the performance change when the performance of the refrigerator changes, and to perform a diagnosis for performing appropriate maintenance according to the priority of maintenance. To do.

The performance diagnosis system of the refrigerator of the present invention has a database regarding the relationship between the performance index value for each component of the refrigerator and the efficiency of the refrigerator, and is obtained from the values included in this database and the measurement data of the refrigerator. It is characterized in that the maintenance location of the refrigerator is specified by using the judgment material including the result of comparing the influence degree of the performance index value for each component on the efficiency.

According to the present invention, when the performance of a refrigerator changes, it is possible to identify the component causing the performance change and perform a diagnosis for performing appropriate maintenance according to the priority of maintenance. it can.

It is a block diagram which shows the performance diagnosis system of the refrigerator of this invention. It is a block diagram which shows the example of the performance diagnosis system of the refrigerator of this invention. It is a block diagram which shows the structure of the double-effect absorption chiller and the installation position of a measurement sensor. It is a flowchart which shows the performance diagnosis method of the refrigerator of an Example. It is a graph which shows an example of the contribution rate of the performance index value which is the breakdown of the cause of the efficiency decrease of a refrigerator. It is a graph which shows the relationship between refrigerating capacity and efficiency. It is a graph which shows the relationship between the performance index value of a component, and the efficiency of a refrigerator. It is a graph which shows the relationship between the increase amount of a condenser LTD and a cycle COP. It is a graph which shows the relationship between the increase amount of a condenser LTD and the contribution rate to the efficiency of a refrigerator. This is an example of a database of performance index values and refrigerator efficiency. This is an example of a database that corresponds to the relationship between the figure of merit and efficiency and the deterioration factors. This is an example of a database in which data for determining maintenance items and the calculation results are described together. This is an example of a display screen showing a part of the measurement data 50 in FIG. 2, a performance index value, and a maintenance location. This is an example of the second screen that displays detailed information such as the performance index value of the absorption chiller.

Hereinafter, examples will be described with reference to the drawings.

FIG. 1 shows a configuration example of the performance diagnosis system of the refrigerator in this embodiment.

In this figure, the performance diagnosis system of the refrigerator is a database of normal values of the arithmetic unit 51 connected to the refrigerator, the output unit connected to the arithmetic unit 51, the display device, the recording device, and the performance index value (first). Database) and a database (second database) on the relationship between performance index values and refrigerator efficiency. The arithmetic unit 51 has a measurement data, an arithmetic unit, a diagnostic unit, and a determination unit. Here, the performance index value is a value that serves as an index for diagnosing the performance of the refrigerator. In addition, the first database and the second database serve as criteria for determining the necessity of maintenance, which will be described later, and use the simulation results of the refrigerator, detailed data in the product test before shipment, and the like. be able to. Examples of the refrigerator include a turbo chiller, an absorption chiller, and the like.

The measurement data includes the actual temperature data of the refrigerator and the like. The measurement data is used in the calculation unit when calculating the efficiency and performance index value of the refrigerator. The calculated efficiency and performance index values of the refrigerator are compared with the first database by the diagnostic unit to determine whether or not they are normal. The determination unit determines the maintenance location using the performance index value calculated from the measurement data and the second database. The determination result is sent to the output unit, and if necessary, is transmitted to the display device and the recording device via the network.

FIG. 2 shows a part of a configuration example of the performance diagnosis system of the absorption chiller.

In this figure, the performance diagnostic device has the measurement data 50 and the arithmetic unit 51. The measurement data 50 includes the chilled water inlet temperature, the chilled water outlet temperature, the chilled water flow rate, and the like. The arithmetic unit 51 has an efficiency arithmetic unit, a performance determination unit, an element diagnosis unit, and a maintenance determination unit.

The efficiency calculation unit takes in the measurement data 50 and calculates the refrigerating capacity, the efficiency of the refrigerator, and the like.

The calculated efficiency of the refrigerator is determined by the performance determination unit as to whether or not it is an abnormal value by comparing it with a normal value. The element diagnosis unit calculates the performance index value of each component. The obtained performance index value obtains the influence on the efficiency of the refrigerator from the database of the relationship between the performance index value and the efficiency of the refrigerator, and the maintenance determination unit determines the necessity of maintenance. In the output section, the result is displayed on the screen or paper.

The calculation result can be displayed on another display device through the network. In addition, the calculation result can be stored in the recording device via the network. It is not necessary to have a network, but the presence of a network makes it possible to grasp the state of the device even at a remote location.

Further, the arithmetic unit 51 may be attached to the absorption chiller as a function of the absorption chiller, but the arithmetic unit 51 may be arranged on a server or the like by connecting the measurement data 50 to the network.
Although the output unit is connected to the display device and the recording device via the network, the refrigerator and the arithmetic unit may be connected to the network.

Further, by arranging the arithmetic unit 51 on a server or the like, restrictions such as calculation speed and recording capacity are almost eliminated, the calculation processing capacity is improved, and the measurement data 50 and the calculation result are recorded for decades. Can be done. Further, the calculation process may be distributed processing through the network. The recorded measurement data and calculation results can be viewed from anywhere in the world, although access is restricted by security, as long as they are connected to the network.

FIG. 3 is a configuration diagram showing a configuration of a double-effect absorption chiller to which the present invention is applied and an installation position of a measurement sensor.

In this figure, the absorption chiller includes an evaporator 1, an absorber 2, a high temperature regenerator 3, a low temperature regenerator 4, a condenser 5, a low temperature heat exchanger 6, and a high temperature heat exchanger 7. The low temperature heat exchanger 6 and the high temperature heat exchanger 7 may be referred to as solution heat exchangers.

An example in which water is used as the refrigerant and an aqueous solution of lithium bromide is used as the absorbing liquid will be described.

The evaporator 1 has a heat transfer tube through which cold water passes. The inside of the evaporator 1 is in a reduced pressure state in which air is removed and is lower than the atmospheric pressure, and the gas phase is kept in a state of being substantially filled only with water vapor. The refrigerant accumulated at the bottom of the evaporator 1 is sprayed on the chilled water heat transfer tube by the refrigerant pump 40 and evaporates. The water in the chilled water heat transfer tube is cooled because heat is taken away by the heat of vaporization of the refrigerant. The refrigerant (water) inside the evaporator 1 is set to evaporate at about 4 ° C. by heat exchange with cold water.

The vaporized refrigerant is absorbed by the lithium bromide aqueous solution in the absorber 2. The lower the temperature of the lithium bromide aqueous solution, the easier it is to absorb steam. Therefore, the cooling water is passed through the cooling water heat transfer tube provided inside the absorber 2 and the lithium bromide aqueous solution is sprayed outside the tube for cooling. It is supposed to be done.

The absorbing liquid whose concentration of lithium bromide is reduced by absorbing the refrigerant vapor is sent from the absorber 2 to the high temperature regenerator 3 by the solution pump 41. Meanwhile, the absorbing liquid passes through the low temperature heat exchanger 6 and the high temperature heat exchanger 7. By heating the absorption liquid in the heating unit 8, the refrigerant in the absorption liquid is evaporated and separated, and the absorption liquid is concentrated. City gas, heavy oil, steam, or the like is used as the heating source of the heating unit 8. The temperature of the absorbing liquid in the high temperature regenerator 3 is measured by the high temperature regenerator temperature sensor 17.

The refrigerant evaporated in the high temperature regenerator 3 is sent to the condenser 5 via the drain pipe. The drain pipe passes through the inside of the low temperature regenerator 4 on the way. At that time, the high-temperature refrigerant passing through the drain heat transfer tube and the absorbing liquid sent to the inside of the low-temperature regenerator 4 and sprayed are heat-exchanged. The absorbing liquid sent to the low temperature regenerator 4 is sent via a pipe branched between the low temperature heat exchanger 6 and the high temperature heat exchanger 7. The refrigerant generated from the absorbing liquid heated by the low temperature regenerator 4 is sent to the condenser 5. The absorption liquid concentrated by the high temperature regenerator 3 and the low temperature regenerator 4 is sent to the low temperature heat exchanger 6 by the solution spray pump 42, and the absorber 2 absorbs the refrigerant vapor to exchange heat with the diluted absorption liquid. Then, it is returned to the absorber 2.

The condenser 5 has a heat transfer tube through which cooling water passes. The refrigerant vapor generated in the high-temperature regenerator 3 and the low-temperature regenerator 4 is sent to the condenser 5, becomes a liquid by heat exchange with the heat transfer tube through which the cooling water passes, and accumulates at the bottom of the condenser 5. The accumulated refrigerant is sent to the evaporator 1.

The low-temperature heat exchanger 6 and the high-temperature heat exchanger 7 apply the heat of the high-temperature absorption liquid to the low-temperature absorption liquid in the process from the absorption liquid flowing from the absorber 2 to the high-temperature regenerator 3. As a result, the low-temperature absorbing liquid is preheated, and the fuel of the heating source of the heating unit 8 is saved.

The cold water pipe is connected to the indoor unit, and the cooling water pipe is connected to the cooling tower.

As shown in FIG. 3, the absorption chiller is equipped with a sensor for diagnosing the performance of each component.

Cold water pipe, cold water for measuring the cold water inlet temperature sensor 11 for measuring the cold water inlet temperature T _{a_in,} coolant outlet temperature sensor 12 for measuring the cold water outlet temperature T _{a_out,} and coolant flow rate V _a A flow rate sensor 60 is provided. An ultrasonic flow meter or the like may be used to measure the flow rate of chilled water, but the flow rate may be obtained from the differential pressure between the inlet pressure of chilled water and the outlet pressure of chilled water. Since the flow meter is more expensive than the pressure meter, the cost for measuring the flow rate can be reduced by using the pressure meter.

Refrigerating capacity _{R c} is coolant flow rate _{V a,} with cold water specific heat _{C a} and the cold water density [rho _a, is calculated by the following equation (1).

The cooling water piping, cooling water inlet temperature sensor 14 for measuring the inlet temperature T _{Co_in} cooling water, the cooling water outlet temperature sensor 15 for measuring the outlet temperature T _{Co_out} of coolant, and the coolant flow rate V A cooling water flow rate sensor 61 for measuring _{co is provided.} To measure the flow rate Ρ _{co of} cooling water, an ultrasonic flow meter or pressure gauge is used in the same way as for cold water.

In addition, when it is known in advance that the flow rate does not change, or when it is difficult to install a sensor for flow rate measurement, the flow rate value at the time of equipment installation is used to calculate the refrigerating capacity and heat dissipation amount. It is not necessary to measure at all times. By not constantly measuring the flow rate, electricity costs and data memory can be reduced.

The heat radiation amount R _r is calculated by the following formula (2) using the cooling water flow rate V _co , the cooling water specific heat C _co, and the cooling water density Ρ _co.

The efficiency of the refrigerator is calculated by the following formula (3) or (4).

When the flow rate of the heating source of the heating unit 8 such as gas or heavy oil can be measured, the COP (efficiency) of the above formula (3) is calculated. If the flow rate of the heating source of the heating unit 8 cannot be measured even with gas or heavy oil, or if it is difficult to measure the amount of heat consumed by the heating unit 8 such as steam-fired or hot-water-fired, the cycle of the above formula (4) Calculate COP. These calculations are performed by the efficiency calculation unit. The denominator of the above formula (4) ((heat dissipation amount)-(freezing capacity)) is defined as "heat input amount".

FIG. 4 is a flowchart showing a diagnostic processing process in the performance diagnostic system of the refrigerator of the present invention.

The efficiency calculation unit calculates the efficiency of the refrigerator (step S1), and the performance determination unit determines whether the efficiency of the refrigerator is normal (step S2). When it is normal, it is called "normal time" when the refrigerator is operating normally.

The element diagnosis unit calculates and diagnoses the performance index value of each component (component) (step S3). Using the database on the relationship between the efficiency of the refrigerator and the performance index value of each component, how much the performance index value of each component calculated in step 3 affects the efficiency, in other words, each component The degree of influence of the performance index value (“contribution rate” described later) is calculated (step S4). This makes it possible to compare the degree of influence.

The maintenance determination unit determines the necessity of maintenance (step S5). In this case, it is determined that the component having a large degree of influence has a high need for maintenance. On the other hand, if there is a component that requires maintenance when the predetermined value is reached even if the degree of influence is small, the maintenance of the component may be prioritized. Therefore, in step S5, other than the degree of influence, it may be a material for determining the necessity of maintenance. In other words, the determination in step S5 may not only compare the magnitude of the influence. In summary, in step S5, a judgment material including the result of comparing the value contained in the database with the degree of influence of the performance index value for each component obtained from the measurement data of the refrigerator on the efficiency of the refrigerator is used. Identify the maintenance location of the refrigerator.

In the output unit (terminal screen, data printing machine, etc.), the degree of abnormality, the degree of influence, etc. of each element that the person in charge of work needs to recognize is displayed (step S6). At this time, it is desirable to display the items that require high maintenance, the priority of maintenance, and the like.

As a result, maintenance (repair) can be performed according to the display, and it is possible to avoid replacement of parts on a scale larger than necessary.

FIG. 5 illustrates the breakdown of the causes of the efficiency reduction when the efficiency of the refrigerator is reduced by 10%. The percentage shown as a breakdown in the figure represents the degree of influence of the performance index value of each component on the efficiency of the refrigerator as a reduction in the efficiency, and in the present specification, the “contribution” of the performance index value is expressed. Call it "rate". The contribution rate is calculated in step S4 of FIG.

In the example shown in FIG. 5, the effect of the efficiency decrease due to the dirt on the cooling water tube is the largest. The contribution rate is 5%, which accounts for half of the decrease in the efficiency of the refrigerator. If there is something that does not fit into the database of performance index values and refrigerator efficiency, it is treated as "other". Even in this case, the component causing the efficiency decrease can be identified by determining the cause of the performance decrease by combining a plurality of performance index values.

As a result, when the efficiency is reduced, the causative factor can be visualized and confirmed. By visualizing the causative factors, it is possible to quickly maintain the refrigerator. Further, by determining the necessity of maintenance by the maintenance determination unit, only the parts requiring maintenance can be maintained.

Further, the efficiency of the refrigerator and the degree of abnormality of each element may be calculated in advance before diagnosing the performance of the refrigerator. However, the processing time can be determined by first determining the efficiency of the refrigerator. Can be reduced.

FIG. 6 is a graph showing an example of COP (efficiency) in a normal state with respect to the refrigerating capacity when the rated refrigerating capacity is 1. The horizontal axis is the ratio to the rated refrigerating capacity (refrigerating capacity ratio), and the vertical axis is COP (efficiency). Here, the refrigerating capacity ratio is the ratio of the measured refrigerating capacity to the rated refrigerating capacity.

In this figure, the curve is convex upward, and the COP (efficiency) is maximum when the refrigerating capacity ratio is around 0.4.

Regarding the refrigerating capacity during operation, it is desirable to compare the COP during operation with the COP during normal operation. However, having a database of the effects of the performance indicators of each component on all COP values would result in a huge amount of data. Since the amount of change in the value of each ability is small, the COP may be the degree of influence on the average value of the COP in the normal state, for example, the average value of 1.35 in the case of the graph of FIG.

The element diagnosis unit determines the performance of the components of the absorption chiller. _{The chilled water outlet temperature Ta_out} and the evaporation temperature T _eva are used for the diagnosis of the evaporator 1 (FIG. 3). Since it is difficult to measure the evaporation temperature _Teva by installing a temperature sensor near the cold water heat transfer tube in the evaporator 1, an evaporator refrigerant temperature sensor 13 is installed near the outlet of the evaporator 1 and if necessary. The measured value is corrected to obtain the evaporation temperature T _eva . _{If the evaporation temperature T eva} rises when the chilled water flow rate is constant, the degree of vacuum of the evaporator 1 may be deteriorated.

A chilled water heat transfer tube passes through the evaporator 1, and when the inside of the chilled water heat transfer tube becomes dirty, the value of the evaporator LTD (Leaving Temperature Difference) becomes larger than the normal value. The evaporator LTD is calculated by the following formula (5). The value of the evaporator LTD indicates that the cold water heat transfer tube is dirty.

Further, as another method for determining the performance of the evaporator 1, the value of KAe represented by the following formula (6) may be used. If the heat transfer performance deteriorates due to dirt on the cold water heat transfer tube or the like, the KAe value decreases.

Further, as another method for diagnosing the performance of the evaporator 1, the temperature efficiency η _A represented by the following formula (7) may be used for evaluation.

In the above formulas (5) to (7), the performance of the evaporator 1 may be diagnosed using only one of them, or all of them may be used. By using all of them, more accurate diagnosis becomes possible.

For the diagnosis of the absorber 2, the concentration of the absorbent (lithium bromide) contained in the absorber 2 is used. When an abnormality of the solution pump or solution spray pump for sending the absorbent liquid, clogging of the heat transfer tube due to crystal precipitation, or the like occurs, the concentration of the absorbent contained in the absorber 2 changes. The concentration of the absorbent is corrected by the absorber outlet temperature sensor 16 as necessary, the equilibrium temperature of the absorbent liquid inside the absorber 2 is calculated, and the chilled water outlet temperature is corrected as necessary. , Calculated by obtaining the saturation temperature of the refrigerant.

Further, the performance of the absorber may be determined by using the value of the absorber ATD (Approaching Temperature Difference) represented by the following formula (8). Here, T _sAo is the absorber outlet temperature, and T _{CD_in} is the cooling water inlet temperature.

For the diagnosis of the high temperature regenerator 3, the concentration of the absorbent contained in the high temperature regenerator 3 and the pressure of the high temperature regenerator 3 are used. If an abnormality occurs in the solution pump or solution spray pump for sending the absorbent liquid, or if the heat transfer tube is clogged due to crystal precipitation or the like, the concentration of the absorbent becomes higher than the normal value. For the concentration of the absorbent contained in the high temperature regenerator 3, the equilibrium temperature of the absorbent liquid in the high temperature regenerator 3 is calculated from the high temperature regenerator outlet temperature measured by the high temperature regenerator outlet temperature sensor 22, and the low temperature regenerator refrigerant is used. It is calculated by obtaining the saturation temperature in the high temperature regenerator 3 from the temperature sensor 20.

When the low-temperature regenerator refrigerant temperature sensor 20 cannot be installed, the concentration of the absorbent in the high-temperature regenerator 3 is calculated from the pressure of the high-temperature regenerator 3. Further, the performance may be diagnosed by the pressure value of the high temperature regenerator 3.

For the diagnosis of the low temperature regenerator 4, the concentration of the absorbent contained in the low temperature regenerator 4 is used. The low temperature regenerator solution outlet temperature sensor 21 is corrected as necessary to calculate the equilibrium temperature of the absorbed liquid inside the low temperature regenerator 4, and the condenser refrigerant temperature sensor 19 installed near the outlet of the condenser 5 is used. If necessary, the saturation temperature of the refrigerant inside the low temperature regenerator 4 is calculated, and the concentration of the absorbent contained in the low temperature regenerator 4 is calculated.

The cooling water outlet temperature T _{CD_out} and the condensation temperature T _Ce are used for the diagnosis of the condenser 5. Since it is difficult to measure the condensation temperature T _Ce by installing a temperature sensor near the cooling water heat transfer tube in the condenser 5, a condenser refrigerant temperature sensor 19 is installed and the measured value is corrected as necessary. The condensation temperature is T _Ce .

A cooling water heat transfer tube passes through the condenser 5, and when the inside of the cooling water heat transfer tube becomes dirty, the value of the condenser LTD becomes larger than the normal value. The condenser LTD is calculated by the following formula (9). The condenser LTD shows dirt in the cooling water heat transfer tube.

Further, as another method for determining the performance of the condenser 5, the value of KAc represented by the following formula (10) may be used. If the heat transfer performance deteriorates due to dirt on the cooling water heat transfer tube or the like, the KAc value decreases.

Further, as another means for diagnosing the performance of the condenser 5, the temperature efficiency η _C represented by the following formula (11) may be used for evaluation.

In the above formulas (9) to (11), the performance of the condenser 5 may be diagnosed using any one of these formulas, or all of them may be used. By using all of them, more accurate diagnosis becomes possible.

If it is possible to measure the cooling water temperature between the outlet of the absorber 2 and the inlet of the condenser 5, the cooling water intermediate temperature T _{CD_mid} is defined as the cooling water temperature in the above equations (9) to (11). The value is calculated using _{T CD_mid} instead of the water inlet temperature T _{CD_in.} By using the cooling water intermediate temperature T _{CD_mid} , more accurate diagnosis becomes possible.

The performance of the low temperature heat exchanger 6 is diagnosed by _{the temperature efficiency η lLX of the low temperature side fluid.} The temperature of the low temperature heat exchanger rare solution outlet temperature sensor 28 is _{defined as the low temperature heat exchanger rare solution outlet temperature T sLXwo,} and the temperature of the low temperature heat exchanger concentrated solution inlet temperature sensor 26 is _defined as the low temperature heat exchanger concentrated solution inlet temperature T sLXsi. The temperature of the absorber outlet temperature sensor 16 is _{defined as the absorber outlet temperature T sAo,} and the temperature efficiency η _lLX of the low temperature side fluid is calculated from these values by the following equation (12).

Further, the performance of the low temperature heat exchanger 6 may be diagnosed by _{the temperature efficiency η hLX of the high temperature side fluid.} In this case, the temperature of the low temperature heat exchanger concentrated solution outlet temperature sensor 27 is set to the low temperature heat exchanger concentrated solution outlet temperature T _{sLXso , and η hLX} is calculated using the following equation (13).

If holes are formed in the heat transfer tube or crystals are deposited inside the heat transfer tube, the temperature efficiency is lowered. Therefore, the performance of the heat exchanger can be diagnosed with temperature efficiency.

The performance of the high temperature heat exchanger 7 is diagnosed by _{the temperature efficiency η hHX of the low temperature side fluid.} The temperature of the high temperature heat exchanger rare solution outlet temperature sensor 24 is set to the high temperature heat exchanger rare solution outlet temperature T _sHXwo , the temperature of the high temperature regenerator outlet temperature sensor 22 is set to the high temperature regenerator outlet temperature T _sFBo , and the high temperature heat exchanger rare solution. The temperature of the inlet temperature sensor 23 is set to the high temperature heat exchanger rare solution inlet temperature T _{sHXwi , and η lHX} is calculated using the following formula (14).

Further, the performance of the high temperature heat exchanger 7 may be diagnosed by _{the temperature efficiency η hHX of the high temperature side fluid.} In this case, the temperature of the high temperature heat exchanger concentrated solution outlet temperature sensor 25 is set to the high temperature heat exchanger concentrated solution outlet temperature T _{sHXso , and η hHX} is calculated using the following formula (15).

When a fuel (heavy oil, etc.) that generates soot or the like during combustion is used as the heating source of the heating unit 8, the surface of the heat transfer tube of the high temperature regenerator becomes dirty, and the heat of the heating unit 8 is transferred to the high temperature regenerator 3. Since it is difficult to transmit, the efficiency of the absorption chiller is reduced. The dirt on the surface of the heat transfer tube of the high temperature regenerator is determined by using the following formula (16) _{by the high temperature regenerator temperature THG measured by the high temperature regenerator temperature sensor 17 and the exhaust gas temperature TEXG} measured by the exhaust gas temperature sensor 18. Evaluate by the calculated high temperature regenerator LTD.

In this embodiment, the absorption chiller in the case of double effect has been described, but it may be used in other absorption chillers such as single effect and triple effect. In that case, the temperature sensor is increased or decreased according to the components.

By using these mathematical formulas, the state of each component can be diagnosed.

In addition, it is possible to determine whether the abnormality is inside the cycle of the absorption chiller or the abnormality on the heating source side such as gas or hot water. Appropriate maintenance can be performed by identifying the abnormal location.

The maintenance determination unit has a database of the effects of the performance index values represented by the above equations (5) to (16) on the efficiency of the refrigerator.

FIG. 7 shows a generalized relationship between the performance index values of the components and the efficiency of the refrigerator. The components include those illustrated in FIG.

As shown in this figure, as the performance index value of the component increases, the efficiency of the refrigerator decreases.

In the case of the absorption chiller, the performance index values include the temperature efficiency of the condenser LTD, the evaporator LTD, the absorber ATD, the heat exchanger, and the solution concentration.

When the efficiency of the refrigerator is reduced, the contributions related to the efficiency reduction of each component are added up to obtain the "efficiency reduction rate" represented by the following formula (17).

FIG. 8A shows the relationship between the increase in the condenser LTD of the absorption chiller and the efficiency of the refrigerator (cycle COP) as an example showing the relationship between the performance index value of the component and the efficiency of the refrigerator. Is.

As shown in this figure, when the condenser LTD changes by 2K, the cycle COP decreases by about 4%.

FIG. 8B shows the degree of influence of the condenser LTD on the efficiency of the vertical axis of FIG. 8A, with the decrease in the efficiency of the refrigerator as the contribution rate to the efficiency of the refrigerator.

The system of the present invention holds a database regarding the degree of influence on the efficiency of the refrigerator (contribution rate to efficiency) when the performance index value of each component changes.

FIG. 9 shows an example of the database.

As shown in this figure, the system of the present invention holds data for each performance index value of each component as to how much the efficiency changes when the component value of each component changes. ..

For example, in the case of the condenser LTD, an increase of 1K reduces the efficiency of the refrigerator by 1.9%. When it is stored as table data, if the performance index value shows an intermediate value, for example, 1.6K, it may be rounded off and the degree of influence of the efficiency of the 2K value may be referred to.

As the form of the database, a function showing the relationship between the performance index value and the efficiency of the refrigerator may be used instead of the table. For example, in the case of the condenser LTD shown in FIG. 8B, the function represented by the following equation (18) is used as the database.

By using such a function, it is possible to calculate an accurate value rather than rounding off the intermediate value using table data.

The database showing the performance index value and the efficiency of the refrigerator stores the data calculated in advance for each model in the memory. In addition, a database may be created for each device from the test results of the performance test at the time of shipment. By creating a database for each device, individual differences of individual refrigerators can be reflected, so diagnosis can be made more accurately.

Maintenance may be performed from the one with the highest contribution rate of the performance index value of each component. That is, after calculating the contribution rate of the performance index value of each component, the priority of maintenance can be determined from the one having the largest influence on the efficiency of the refrigerator. As a result, proper maintenance of the refrigerator can be performed, and as a result, the efficiency of the refrigerator can be maintained with a minimum of repair and parts replacement work. Therefore, it is possible to reduce the cost of repair and the like, which is the running cost of the refrigerator, and the fuel cost.

In addition to the effect on the efficiency of the refrigerator, the priority of maintenance may be determined in consideration of the cost and period of maintenance, the non-operating time of the refrigerator at the time of repair, the progress rate of deterioration, and the like. For example, even if the degree of influence on efficiency is small, it is advisable to first maintain an abnormal part that directly leads to a device failure. As a result, the failure of the refrigerator can be prevented and maintenance can be performed efficiently. By performing maintenance efficiently, maintenance costs can be minimized and the performance of the refrigerator can be ensured.

Further, the logic for determining the priority of maintenance may be programmed in advance so that the device (system) automatically determines and displays the determination result. By making an automatic judgment, the priority of maintenance becomes clear at a glance, and maintenance personnel can perform maintenance without hesitation.

If the efficiency of the refrigerator has not changed and the performance index value is equal to or higher than a predetermined threshold value or there is no measured value, maintenance is displayed as a sensor abnormality.

Next, the database required to determine the maintenance items will be described.

FIG. 10A is an example of a database in which the relationship between the performance index value and the efficiency and the deterioration factor thereof are associated with each other.

FIG. 10B is an example of a database in which data for determining maintenance items and calculation results thereof are shown together.

As shown in FIG. 10A, the system of the present invention has a database of the degree of influence on the efficiency of the refrigerator (contribution rate to efficiency) when each performance index value changes. In addition, the deterioration factors and the corresponding maintenance contents are stored in advance as a database.

When each figure of merit changes, the effect of the change on the efficiency of the refrigerator is calculated in step S4 of FIG. 4, and the estimated amount of recovery of the efficiency of the refrigerator due to maintenance is calculated. Maintenance may be performed for items with a high efficiency recovery amount, but for example, if the value of the cost required for maintenance or the weighting coefficient is saved as a database in advance, the item with a high efficiency improvement effect per cost should be preferentially maintained. Can be done.

In the case of the example shown in FIG. 10B, the cooling water heat transfer tube is cleaned as a maintenance content.

Here, when considering the maintenance of the refrigerator, in the case of the absorption chiller, the performance related to the heat source such as the boiler is regarded as the heat input performance, and the performance related to the inside of the refrigerator such as the condenser is considered as the cycle performance. It is good. The overall performance (efficiency of the refrigerator) is the sum of the heat input performance and the cycle performance as shown in the following formula (19).

By dividing into heat input performance and cycle performance, it becomes easy to understand that an abnormality has occurred on either the outside of the refrigerator or the inside of the refrigerator. In the case of the inside of the refrigerator, maintenance work is often large-scale, but if an abnormality progresses, the refrigerator may not operate. Therefore, it is useful when prioritizing maintenance.

More specifically, the heat input performance and the cycle performance are distinguished as follows.

In the case of an absorption chiller, the heat input performance is the performance on the outside of the refrigerator, that is, on the atmosphere side, and exchanges heat with heat sources such as boilers, cooling water such as absorbers and condensers, and cold heat generated in evaporators. Performance related to cold water, etc. For example, in the case of a gas-fired boiler, soot, rust, etc. adhering to the surface (heat exchange surface with the absorption liquid, flow path of the combustion gas, etc.) in contact with the combustion gas of the high-temperature regenerator that heats and concentrates the absorption liquid affects it. It is thought that. It is considered that the scale (dirt) in these heat transfer tubes affects the cooling water, cold water, etc.

On the other hand, the cycle performance is the performance on the inside of the refrigerator, that is, on the decompression region side in the case of the absorption chiller, and is the performance on the inside of the absorber, the high temperature regenerator, the condenser, the evaporator and the like. For example, precipitation of crystals from the absorbent liquid in an absorber, high temperature regenerator, etc., mixing of solutes in a condenser, evaporator, etc., mixing of air, generation of gas due to a chemical reaction between the absorbent liquid and the material of the inner wall surface of the container. Etc. are considered to have an effect.

In the case of turbo chillers and other mechanical chillers, the heat input performance is the performance outside the chiller, with defects in the compressor power supply, electrical wiring, electronic circuits, etc., condenser cooling water, and evaporator. It is considered that the scale in the heat transfer tube such as cold water that exchanges heat with the generated cold heat has an effect.

On the other hand, the cycle performance is the performance inside the refrigerator, and it is considered that the distribution of the lubricating oil flowing together with the refrigerant, such as the flow path of the refrigerant, the expansion valve, the dirt inside the compressor, foreign matter, etc., affects the performance.

An example of output in the output unit will be described below.

FIG. 11A shows an example of a part of the measurement data 50 of FIG. 2 and a display screen (first screen) of the performance index value.

In this figure, the rated value and the current value of the refrigerating capacity, efficiency, chilled water outlet temperature and cooling water outlet temperature of the chiller are displayed. In addition, the overall performance, heat input performance, and cycle performance of the refrigerator are also displayed. Then, the maintenance of the condenser is displayed as the state of the refrigerator.

FIG. 11B shows an example of a second screen for displaying detailed information such as the state of each component.

By displaying as shown in this figure, it is possible to provide necessary information without being restricted by the size of the screen. Similar to this figure, it is possible to switch between the third screen and the fourth screen as needed.

In the display example of FIG. 11B, the performance of the evaporator and the condenser is deteriorated, but the performance of the condenser is deteriorated and the efficiency of the refrigerator is greatly affected, and it is displayed that the condenser needs maintenance. ing. The state of each component may be displayed in words such as normal, caution, abnormality, etc., or may be displayed in a bar graph or the like.

Further, the configuration diagram as shown in FIG. 3 may be simplified and displayed, and the temperature or the like may be displayed at each position in the diagram. Displaying as a configuration diagram has the advantage of being easier to understand intuitively than displaying only numerical values.

According to the present invention, when the efficiency of the refrigerator changes, it is possible to identify the location where a defect occurs and determine the priority of maintenance. As a result, the increase in fuel cost can be suppressed.

1: Evaporator, 2: Absorber, 3: High temperature regenerator, 4: Low temperature regenerator, 5: Condenser, 6: Low temperature heat exchanger, 7: High temperature heat exchanger, 8: Heating part, 11: Cold water inlet Temperature sensor, 12: Cold water outlet temperature sensor, 13: Evaporator refrigerant temperature sensor, 14: Cooling water inlet temperature sensor, 15: Cooling water outlet temperature sensor, 16: Absorber outlet temperature sensor, 17: High temperature regenerator temperature sensor, 18: Exhaust gas temperature sensor, 19: Condenser refrigerant temperature sensor, 20: Low temperature regenerator refrigerant temperature sensor, 21: Low temperature regenerator solution outlet temperature sensor, 22: High temperature regenerator outlet temperature sensor, 23: High temperature heat exchanger rare solution Inlet temperature sensor, 24: High temperature heat exchanger rare solution outlet temperature sensor, 25: High temperature heat exchanger concentrated solution outlet temperature sensor, 26: Low temperature heat exchanger concentrated solution inlet temperature sensor, 27: Low temperature heat exchanger concentrated solution outlet temperature Sensor, 28: Low temperature heat exchanger rare solution outlet temperature sensor, 29: Exhaust heat exchanger rare solution outlet temperature sensor, 30: Drain heat exchanger rare solution outlet temperature sensor, 31: Drain heat exchanger Drain outlet temperature sensor, 40 : Refrigerator pump, 41: Solution pump, 42: Solution spray pump, 50: Measurement data, 51: Computational device, 60: Cold water flow sensor, 61: Cooling water flow sensor.

Claims (5)

In a system for diagnosing the performance of refrigerators
It has a database on the relationship between the performance index value for each component of the refrigerator and the efficiency of the refrigerator.
By using a determination material containing the result of comparing the value included in the database with the degree of influence of the performance index value for each component obtained from the measurement data of the refrigerator on the efficiency, the refrigerator can be used. A performance diagnosis system for refrigerators, which is characterized by identifying maintenance points. In the performance diagnosis system of the refrigerator according to claim 1,
The database is a chiller performance diagnostic system that includes chiller simulation results or pre-shipment product test data. In the performance diagnosis system of the refrigerator according to claim 1,
The refrigerator is an absorption chiller.
The performance index value is a performance diagnostic system for a refrigerator, which includes any one or more of a condenser LTD, an evaporator LTD, an absorber ATD, a temperature efficiency of a heat exchanger, and a solution concentration. In the performance diagnosis system of the refrigerator according to claim 1,
A performance diagnosis system for a refrigerator having a function of displaying the total performance, heat input performance, and cycle performance of the refrigerator. In the performance diagnosis system for the refrigerator according to any one of claims 1 to 4.
A performance diagnosis system for a refrigerator having a function of automatically determining the maintenance location.

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