JPH02208460A - Operation monitor for absorption refrigerator - Google Patents

Abstract

PURPOSE:To enhance the efficiency of operation, maintenance and management for an absorption refrigerator by indicating data stored in a data memory means through tables and graphs and also displaying enquiries for failure diagnosis or inference results. CONSTITUTION:A CPU 1, which is a device to monitor and control an absorption refrigerator, stores in time sequence physical quantities, such as temperature, vapor pressure, liquid level in a generator of the absorption refrigerator and the temperature and flow rate of a cooling water flow passage detected from various sensors 2, and respective operation instruction signal values of drive equipment for refrigerator 11 based on a signal of a calendar timer 10, and turns various kinds of data into tables or graphs and indicates them on a display device 5. With regards to enquiries for failure diagnosis from an input device 7, a failure location is inferred in reference to the knowledge base on a memory 4, and the results of enquiries and inference are displayed on the display device 5. It is, therefore, possible to enhance the operation, maintenance and management of the absorption refrigerator.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an operation monitoring device for an absorption refrigerator, an absorption heat pump, or an absorption chiller/heater (hereinafter referred to as an absorption refrigerator), and particularly relates to an operation monitoring device for an absorption refrigerator, an absorption heat pump, or an absorption chiller/heater (hereinafter referred to as an absorption refrigerator). Displays multiple types of information in real time, such as monitoring of current conditions, displaying time-series changes in operating conditions, displaying a Duering diagram representing the internal cycle of an absorption chiller, and a failure diagnosis expert system to identify the location of a failure when a failure occurs. , relates to an operation monitoring device for an absorption chiller that is switched.

(b) Conventional technology Regarding the operational management of absorption chillers, for example, see "Correct operation of gas absorption chiller/heaters and absorption chillers" published by the Japan Refrigeration and Air Conditioning Industry Association (first edition revised in February 1982). It is carried out according to the method.

According to the report, data such as temperature and pressure of each part of the absorption chiller is manually measured by an operation manager at regular intervals, recorded on a recording sheet, and compiled and saved as daily report data.

The operation manager then determines the operating status of the absorption chiller from this daily report data, and takes appropriate action if there is a problem. In addition, if a malfunction occurs in the absorption refrigerator,
Since a lamp on the control panel indicates which system is in trouble, the operations manager can identify the location of the fault based on experience.

This kind of operation maintenance and management requires knowledge and experience from the operation manager, and there is a large amount of work involved.Therefore, with the aim of increasing the efficiency of operation management, we have developed an operation recording device for absorption chiller drive equipment ( (Refer to Japanese Patent Laid-open Publication No. 108968/1983), etc. have been proposed.

This is a system that automatically records the number of times the absorption chiller drive equipment starts and stops, as well as the operation time, instead of manually, and can be retrieved as data in tables and graphs, and is used as a guide for maintenance timing.

By the way, the number of absorption refrigerators that use PID control to control the cold and hot water outlet temperature is increasing, but setting the optimal value of the PID parameter is extremely difficult, and theoretically Z iegle
The r-N 1chols method or the like can be used, but it is not always successful, so the PID parameters are usually fine-tuned by graphing the time-series changes in the measurement data. An absorption refrigerator that automates graphing for this purpose has not yet been developed.

On the other hand, regarding the expert system for failure diagnosis, a system using a laptop computer (Nikkei PC 19
(Refer to October 1988, No. 240, p. 187) has been developed, but an absorption refrigerator with a built-in expert system has not yet been developed.

(c) Problems to be solved by the invention-a. Problems in operation management of absorption chillers include: ■ In order to always operate the absorption chiller in an optimal condition,
It is necessary to know the dynamic characteristics of absorption refrigerators.

Therefore, an operation manager measures the temperature, pressure, etc. of each part of the absorption chiller at regular intervals and creates a table or graph. This work is very complicated and requires a lot of effort.

■ Duering diagrams are used to visually understand the status of the internal cycle of absorption chillers, but currently they are drawn manually, and in order to see moment-to-moment changes, a large number of Duering diagrams are required. must be drawn.

■ In order to take appropriate measures when a failure occurs in an absorption chiller, it is necessary to identify the failure location, analyze the cause of the failure, and take appropriate measures. It depends a lot. Prompt recovery from a failure minimizes the negative impact on others and also saves maintenance costs due to service calls. However, there is no systematic means to pinpoint the location of the failure.

In view of these problems, the present invention aims to provide an operation monitoring device for an absorption refrigerating machine that makes it possible to present information necessary for operational management of an absorption refrigerating machine in the form of tables and graphs that are easy for humans to understand. It is something.

(d) Means for Solving the Problems The absorption chiller operation monitoring device of the present invention senses physical quantities such as the temperature, vapor pressure, and liquid level in the generator of the absorption chiller, and the temperature and flow rate of the cold and hot water flow path. a detection means and a heating device for the generator;
An operating means for instructing the start and stop of each of absorption refrigerating machine driving equipment such as an absorption liquid pump and a refrigerant liquid pump, a data storage means for storing detection signals and operation command signal values in chronological order, and a failure diagnosis function. a failure location inference means having a knowledge database and an inference mechanism for the purpose of the invention; The present invention is characterized in that a display means, an input means for switching the display for arbitrarily selecting the display and inputting a response to the display, and an absorption chiller control section are connected via an interface.

(E) Function According to the present invention, the information necessary for operation management of the absorption chiller is automatically extracted and stored, and the information necessary for operation management of the absorption chiller is automatically stored and displayed in the form of graphs and tables that are easy for humans to understand, such as Düring diagrams and trend charts. This information can be provided to the administrator and displayed in a menu format.
can be displayed on one display device.

(F) Embodiment What is shown in FIG. 1 is a block diagram showing one embodiment of the present invention.

(1) is CP[J, (2) is various sensors for measuring temperature, pressure, etc. of each part of the absorption chiller, (3) is its interface, (4) is memory for storing measurement data, (5)
) is a display device such as a liquid crystal display, plasma display, or CRT. (6) is its interface, (
7) is an input device for switching various information displayed on the display device (5), and is a keyboard or a touch panel. (8) is its interface, (9) is a memory that stores control programs, data processing, display processing programs, etc., (lO) is a calendar timer, +11) is the drive equipment for the absorption refrigerator, and (12) is their This is an interface for starting and stopping. FIG. 2 is a system diagram of the absorption refrigerator drawn on the display device (5) shown in FIG.
For example, if you touch the area where ``Systematic Diagram'' is displayed with your finger, the touch panel detects the movement of your finger and the CPU (1) recognizes that the ``Systematic Diagram'' screen has been selected. Therefore, the CPU (1) displays the "system diagram" shown in FIG. 2 on the display device (5). This "system diagram" displays measurement data obtained from various sensors (2) placed in each part of the absorption chiller in real time at the corresponding locations. Furthermore, the on/off state of each pump is expressed by moving the flame of the gas burner left and right during combustion. By visually presenting each state inside the absorption refrigerating machine to the operation manager using this "system diagram", it is possible to make the operation manager understand the entire operation of the absorption refrigerating machine at a glance.

FIG. 3 is a screen displayed when "Dueling diagram" is selected on the menu screen [1] of FIG. 2.

Based on the data measured by each sensor (2), CPU (1
) is drawn. The drawing method will be explained below based on the double-effect absorption refrigerator shown in FIG. This double-effect absorption refrigerator uses water (820) as a refrigerant and an aqueous solution of lithium bromide (L i Br) as an absorbent (absorbing liquid).

In Figure 4, (21) is a high temperature regenerator equipped with a gas burner (B), (22) is a low temperature regenerator, (23) is a condenser, (24) is an evaporator, (25) is an absorber, ( 26) is a low temperature heat exchanger, (27) is a high temperature heat exchanger, (28) or 32) is an absorption liquid pipe, (33) is an absorption liquid pump, (3
4) or 36) is a refrigerant pipe, (37) is a refrigerant pump, (38) is a gas pipe connected to the gas burner (B),
(39) is a cold water pipe, and (40) is a cooling water pipe, which are connected to each other as shown in the figure. Also, (41)
is a high temperature regeneration pressure detector provided in the high temperature regenerator (21), (42) is a high temperature regeneration temperature detector provided in the high temperature regenerator (21), and (43) is provided in the low temperature regenerator (22). (44) is a condensing temperature detector provided in the condenser (23), (45) is an absorption temperature detector provided in the absorber (25), and (46) is a low temperature regeneration temperature detector provided in the evaporator (23). 24)
This is an evaporation temperature detector installed in the evaporation temperature sensor. Furthermore, (47) is for each detector (413, (421, (43), (44),
It is a control device such as a microcomputer that inputs signals from (45) and (46) and outputs a screen as a Dueling diagram to a plasma display (48).

When operating the above-mentioned double-effect absorption chiller, the high-temperature regenerator (21)
The evaporated refrigerant passes through the low-temperature regenerator (22) and then into the condenser (
23) and exchanges heat with the water flowing in the cooling water pipe (40) to condense and liquefy, and then flows to the evaporator (24) via the refrigerant pipe (35). And the refrigerant liquid is the cold water pipe (39)
It exchanges heat with the water inside and evaporates, and the heat of vaporization causes the cold water piping (
39) The water inside is cooled. Furthermore, the refrigerant evaporated in the evaporator (24) is absorbed into an absorption liquid in the absorber (25). Then, the absorption liquid whose concentration has become diluted by absorbing the refrigerant is transferred to the low-temperature heat exchanger (26) by the operation of the absorption liquid pump (33).
It is sent to the high temperature regenerator (21) via the high temperature heat exchanger (27). The absorption liquid that has entered the high temperature regenerator (21) is transferred to the burner (B
) to evaporate the refrigerant, and the medium-concentration absorption liquid passes through the high-temperature heat exchanger (27) and enters the low-temperature regenerator (22).

The absorption liquid is then transferred from the high temperature regenerator (2I) to the refrigerant pipe (3I).
4) is heated by the refrigerant vapor flowing through the refrigerant, and the refrigerant is further evaporated and separated, increasing its concentration. The highly concentrated absorption liquid passes through a low-temperature heat exchanger (26), where the temperature is lowered and the temperature is lowered into the absorber (26).
5) and is dispersed.

The state of the absorption liquid when the dual-effect absorption refrigerator is operated as described above will be explained based on the Dueling diagram shown in FIG. In Figure 5, fruit! 11(j) is a temperature-pressure diagram of saturated water vapor, and the solid line (k) is a crystal precipitation line of lithium bromide. In addition, point (g) is the state of the absorption liquid (intermediate liquid) determined from the high temperature regeneration temperature (a) and high temperature regeneration pressure (b), and point (h) is determined from the low temperature regeneration temperature (c) and condensation temperature (d). The state of the absorbing liquid (concentrated liquid) determined, point (1), is the state of the absorbing liquid (dilute liquid) determined from the absorption temperature (e) and the evaporation temperature (f). There are two calculation formulas used by the microcomputer. The first is formula f1, which calculates the concentration of the absorption liquid from the temperature and pressure. That is, concentration ζ=fl
(T, P), T: temperature, P: pressure The other formula is 2, which calculates the saturated steam pressure of water from the refrigerant temperature.

That is, saturated steam pressure P=f2(T), T:
Temperature The procedure for displaying the state of the absorption liquid in the absorption refrigerator on the Duering diagram is shown below according to Figure 6. Liquid) concentration is determined from the above formula ξ=fx(T, P).

In addition, the condensation pressure (42) can be calculated from the condensation concentration (d) by the above formula P
= f z (T).

Obtain from (T, P). Further, the evaporation pressure (m) is determined from the evaporation temperature (f) using the above equation P=fz(T). Furthermore, using the obtained evaporation pressure (m), the concentration of the absorbing liquid (dilute liquid) at point (i) is determined from the above equation ξ=ft('r, p).

After calculating the concentrations of the concentrated liquid, dilute liquid, and intermediate liquid as described above, the only thing left to do is to complete the Dueling diagram along the concentration lines. In other words, the intermediate liquid at the high-temperature regenerator volume port at point (g) passes through the pipe (29) with a constant concentration and is transferred to the high-temperature heat exchanger (27).
While exchanging heat with the dilute liquid to lower the temperature, it flows into the low temperature regenerator (22) through the pipe (30).

Since the pressure (R) of this low-temperature regenerator (22) has been previously determined, the point B(n) of the intermediate liquid here can be determined.

This intermediate liquid in state (n) is concentrated to a concentrated liquid in state (h) and flows out from the low temperature regenerator (22). This concentrated liquid passes through the pipe (31) with a constant concentration and passes through the low temperature heat exchanger (26).
) and flows into the absorber (25) through the pipe (32) while lowering the temperature. Since the pressure (m) of this absorber (25) has already been determined, the point of state (0) of this concentrated liquid can be determined. This concentrated liquid at point (0) absorbs refrigerant vapor in the absorber (25) and becomes a dilute liquid at point (1). The diluted liquid in the state of point (i) is absorbed by the absorption liquid pump (3).
3), it is sent again to the high temperature regenerator (21). The diluted liquid in the state of point (i) is passed through the low temperature heat exchanger (26) to the concentrated mixing regenerator (21).
). The high temperature regeneration pressure (b) is detected by a pressure detector (41
), the state of the diluted liquid that has flowed here is expressed as point (p). The concentration of the dilute solution is increased to point (g) again, and the cycle on the Dueling diagram is completed.

The data obtained by these calculations is converted into graphic data by the CPU and displayed on the plasma display. Absorption chiller operating personnel or service personnel can visually grasp the operating status of the absorption chiller by looking at the Düring diagram displayed graphically. This has the effect of dramatically improving the speed of judgment and making it possible to perform accurate processing.

Note that the refrigerant condensation temperature (g) in the low-temperature regenerator (22) is measured by the temperature detector (4) instead of the high-temperature regeneration pressure detector (41).
It goes without saying that the high-temperature regeneration pressure (b) may be determined by p = f 2 (T).

Furthermore, the condensation pressure (j2) of the condenser (23) and the evaporator (2
4) The evaporation pressure (m) may be directly detected by a pressure detector, and this is the screen displayed on the display device.

In this way, by trending (displaying a chart) the temperature and pressure data of each part according to the operating time on the display device (5), the dynamic characteristics of the absorption chiller can be visually expressed, and the operating status of the absorption chiller can be displayed. It is very useful for accurately understanding the
Furthermore, being able to see trends in temperatures related to each part on the same chart at the same time is useful for accurately understanding changes in the environment in which the absorption chiller is operating.

In other words, the load trends, changes in cooling water temperature, and even the control characteristics for load fluctuations can be grasped accurately at a glance, and the operator can accurately operate the absorption chiller. In addition, service personnel can accurately grasp changes in the absorption chiller and the environment in which it is operated, allowing them to perform accurate service and maintenance.Also, they can visually see the dynamic characteristics of the absorption chiller. Therefore, the set value for control, for example, the constant of PID control (P: proportionality constant 1
= Integral constant D: a constant You will be able to clearly see only what you need without having to worry about it, and you will be able to make faster and more accurate decisions. In addition, since the time and temperature axes can be freely enlarged or reduced, it is possible to see the overall trend and even the instantaneous dynamic characteristics, making it possible to maintain the absorption chiller in the optimum condition at all times. This has the effect of making it possible.

The screen shown in FIG. 8 is the screen that is displayed when menu g "Fault diagnosis" is selected. 0 The operation monitoring device of the present invention is in the fault diagnosis mode.

Screen (I): Question window Displays a list of questions to ask when performing fault diagnosis.

[l] Select the question using the l key on screen (V).

Screen (I): Answer window Display example answers for each question.

In the initial state, all possible considerations are displayed.

Screen (■): Results Window (A) Shows the number of conclusions drawn from the conditions set on screens (1) and <1).

Screen (■): Result window (B) Shows the content of the conclusion drawn from the conditions set in screens (1) and (1).

Screen (V): Operation window The currently operable items are displayed.

The failure diagnosis method will be explained using an example in which an absorption chiller cannot be operated. First, select the failure symptom displayed on the screen (I) (If). In this example, the shaded area on the 0 screen (If) for selecting a vehicle that cannot be operated indicates that the brightness has been reversed. In other words, this item is selected. In this state, if you select "Answer Setting" on screen [V], the entire screen changes as shown in FIG. 9. If you can see that the possible outcomes for the symptom of ``unable to drive'' have been narrowed down to 2.1, then the results are further narrowed down to 0 screen (1).
By selecting questions and answering the symptoms, a final conclusion is drawn from the fault diagnosis expert system.

Since the above-mentioned failure diagnosis can be performed, even an operation manager who is inexperienced in managing the operation of absorption chillers can easily identify the failure location and promptly take appropriate measures.

The screen shown in FIG. 10 is the screen that is displayed when "'Monitor'" is selected from the menu. Conventional control units were composed of lamps and numeric displays, but in the present invention, the graphic display on the display device that displays each of the information mentioned above is not included in conventional products. These operations are automatically performed, and they can be displayed as desired in real time, resulting in the effect of improving the efficiency of operation, maintenance, and management of the absorption chiller.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an operation monitoring device for an absorption chiller according to the present invention, Figs. 2 and 3 are explanatory diagrams showing examples of display on the display device in Fig. 1, and Fig. 4 is a double-effect absorption refrigerating machine. The system diagram of the machine, FIGS. 5 and 6 are explanatory diagrams showing a method of drawing a Dueling diagram, and FIGS. 7 to 10 are explanatory diagrams showing examples of display on a display device. (1)...CPU, (2)...Various sensors, (3)
(6) (8) (12)...Interface, (41
(9)...Memory, (5)...Display device, (7)...
... Input device, (10) ... Calendar timer, (1
1)...Drive equipment. Figure 1

Claims (1)

[Claims] (1) Detection means for sensing physical quantities such as the temperature, vapor pressure, and liquid level in the generator of the absorption chiller, and the temperature and flow rate of the cold and hot water flow path, the generator heating device, the absorption liquid pump, and the refrigerant liquid. An operating means for instructing the start and stop of each absorption chiller drive device such as a pump, a data storage means for storing detection signals and operation command signal values in chronological order, and a knowledge database and inference mechanism for fault diagnosis. a failure location inference means, a display means for displaying the data stored in the storage element of the data recording means in the form of a table or a graph, and displaying questions and inference results for fault diagnosis; 1. An operation monitoring device for an absorption refrigerating machine, characterized in that an input means for switching a display for selection and inputting a response to the display, and an absorption refrigerating machine control section are connected via an interface.