JP3208165B2 - Abnormality detector for absorption refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerator, and more particularly, to a device for detecting an abnormality of an absorption refrigerator, which detects an abnormality of an evaporator.

[0002]

2. Description of the Related Art For example, in Japanese Patent Application Laid-Open No. 1-142374, a temperature detector and a pressure detector are installed in an internal space of an evaporator, and output signals from the respective detectors are inputted. A refrigerator protection device including a setting device that outputs a refrigerator stop signal and an alarm signal when a value is reached is disclosed.

[0003]

In the above prior art, when the load increases while an abnormality occurs in the refrigerator, the pressure or temperature of the evaporator rises, and the stop signal of the refrigerator and the Although an alarm signal is output, when the refrigerator is partially loaded or when there is almost no load, the abnormality of the evaporator cannot be accurately detected, so that there is a problem that the detection of the abnormality of the refrigerator is delayed. Conventionally, whether or not the capacity of the refrigerator is insufficient is determined by, for example, whether or not the difference in temperature between the inlet and the outlet of the chilled water is equal to or more than the rated value, with the amount of combustion in the regenerator of the absorption refrigerator being 100%. . With such a determination method, there is a problem that it is not possible to determine the abnormality of the absorption chiller when the absorption chiller is partially loaded, as in the case of the abnormality determination of the evaporator.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an absorption refrigerator having a high-temperature regenerator 4, a condenser 7, an evaporator 1 and an absorber 2 connected by piping. Chilled water temperature detectors 36 and 37 for detecting the chilled water inlet temperature and the outlet temperature of the evaporator 1, a refrigerant temperature detector 38 for detecting the refrigerant temperature on the outlet side of the evaporator 1, and the detected temperature of each chilled water temperature detector. The chilled water load is calculated from the difference and the chilled water inlet / outlet temperature difference at 100% load, and the actual logarithmic average temperature difference of the evaporator is calculated from the detected temperatures of the chilled water temperature detector and the refrigerant temperature detector. An abnormality detector that includes an abnormality detector that outputs an abnormality signal by comparing an average temperature difference and a chilled water load, and that reliably detects an abnormality of the evaporator even when a partial load is applied to the absorption refrigerator. Things.

Further, chilled water temperature detectors 36 and 37 for detecting the chilled water inlet temperature and the outlet temperature of the evaporator 1 respectively, a pressure detector 45 for detecting the pressure in the evaporator 1, and these pressure detectors detect the temperature. The saturation temperature is obtained from the pressure, the actual logarithmic average temperature difference is calculated from the saturation temperature and the detection temperature of each chilled water temperature detector 36, 37, and the difference between the detected temperature of each chilled water temperature detector and 100% load A chilled water load is calculated from the chilled water inlet / outlet temperature difference, and an abnormality detector that outputs an abnormal signal by comparing the chilled water load with an actual logarithmic average temperature difference,
An object of the present invention is to provide an abnormality detection device that reliably detects an abnormality of the evaporator 1 before the temperature of the chilled water changes due to an abnormality even when the absorption refrigerator is partially loaded.

[0006] Chilled water temperature detectors 36 and 37 for detecting a chilled water inlet temperature and an outlet temperature of the evaporator 1 respectively;
A refrigerant temperature detector 38 for detecting the refrigerant temperature at the outlet side of
The relationship between the chilled water load when the evaporator 1 is healthy and the ideal logarithmic mean temperature difference is stored, and the chilled water load is determined from the difference between the detected temperatures of the respective chilled water temperature detectors and the chilled water inlet / outlet temperature difference when the load is 100%. Calculated, the ideal logarithmic mean temperature difference corresponding to the chilled water load is obtained from the relationship between the chilled water load and the ideal logarithmic average temperature difference corresponding to the chilled water load, and The actual log average temperature difference of the evaporator 1 is calculated from the detected temperatures of the chilled water temperature detectors 36 and 37 and the refrigerant temperature detector 38, and the actual log average temperature difference and the ideal log average temperature difference are compared to determine the ideal log average temperature. Equipped with an abnormality detector that outputs an abnormality signal when the ratio of the actual logarithmic average temperature difference to the temperature difference is equal to or greater than a predetermined value, and accurately distinguishes and absorbs changes in chilled water temperature due to changes in chilled water load and other abnormalities. Type refrigerator Even at partial load there is provided an abnormality detecting apparatus to reliably detect the abnormality of the evaporator 1.

[0007]

During operation of the absorption chiller, the abnormality detector 40 inputs signals from the chilled water temperature detectors 36 and 37 and the refrigerant temperature detector 38 to determine the difference between the chilled water inlet / outlet temperature difference and the chilled water inlet / outlet temperature difference at 100% load. , And the actual logarithmic average temperature difference is calculated from the temperature of the cold water inlet and outlet and the refrigerant temperature. If the logarithmic average temperature difference exceeds the abnormal line of the logarithmic average temperature difference of the load at that time, the abnormality detector 40 outputs an abnormality signal to notify the abnormality of the evaporator 1, so that the abnormality other than the summer season is performed. An abnormality can be detected even when the absorption refrigerator has a partial load in spring or the like, and maintenance and inspection work can be performed early on abnormality of the evaporator.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows that the refrigerant is, for example, water and an absorbing liquid (solution).
FIG. 1 is a schematic configuration diagram of an absorption chiller / heater, which is an absorption refrigerator using a lithium bromide (LiBr) solution, wherein 1 is an evaporator,
Reference numeral 2 denotes an absorber, 3 denotes an evaporator absorber body (hereinafter, referred to as a lower body) containing the evaporator 1 and the absorber 2, 4 denotes a high-temperature regenerator provided with, for example, a gas burner 5 and heated by a high-temperature heat source, 6
Is a low-temperature regenerator, 7 is a condenser, 8 is a low-temperature regenerator condenser body (hereinafter referred to as an upper body) containing the low-temperature regenerator 6 and the condenser 7, 9 is a low-temperature heat exchanger, and 10 is a high-temperature heat exchanger. , 11 to 15 are absorption liquid pipes, 16 is an absorption liquid pump, 17 and 18 are refrigerant pipes, 19 is a refrigerant circulation pipe, 20 is a refrigerant pump, 21 is a gas pipe connected to the gas burner 5, 22 is a heating amount. The control valve 23 is a cold water pipe provided with an evaporator heat exchanger 24 on the way, and each is connected to the pipe as shown in FIG.

Reference numeral 25 denotes a cooling water pipe, and an absorber heat exchanger 26 and a condenser heat exchanger 27 are provided in the cooling water pipe 25. 28 is a refrigerant bypass pipe connecting the refrigerant reservoir 29 of the evaporator 1 to the absorbent reservoir 30 of the absorber 2, 31 is an on-off valve, 32 is an absorbent bypass pipe connecting the absorbent pipe 12 and the absorber 2. , 33 is an on-off valve,
34 is a refrigerant vapor bypass pipe connecting the refrigerant pipe 17 and the absorber 2, and 35 is an on-off valve, and each of the on-off valves 31, 33,
35 is closed when supplying cold water and opened when supplying hot water.

Reference numerals 36 and 37 denote first and second temperature detectors which are chilled water inlet / outlet temperature detectors provided on the inlet side and outlet side of the evaporator 1 of the chilled water pipe 23, respectively. This is a refrigerant temperature detector provided on the suction side of the refrigerant pump 20 of the pipe 19. Reference numeral 40 denotes an abnormality detector, which is provided, for example, on a control panel (not shown) of the absorption refrigerator and is constituted by a microcomputer. Reference numeral 41 denotes a notification device provided on the control panel similarly to the abnormality detector 40 and operates by inputting a signal from the abnormality detector. The notification device 41 includes, for example, a display device 42 having a plurality of segment elements and a buzzer 43. Then, the display device 42 displays the abnormality detector 4
The character “ALARM” blinks based on the signal from “0”.

Hereinafter, the configuration of the abnormality detector 40 will be described with reference to FIG.
It will be described based on. 44 is the first and second temperature detectors 3
6, 37 and a central processing unit (hereinafter referred to as CPU) 4 which receives signals from the refrigerant temperature detector 38, converts the signals, and converts the signals.
Reference numeral 46 denotes a storage device (hereinafter referred to as a ROM) in which an arithmetic program or the like according to the present invention is stored; 47, an output interface for receiving a signal from the CPU 44 and outputting the signal to the notification device 41; -Face, 4
Reference numeral 8 denotes a signal generator (hereinafter referred to as CL) which outputs a signal every predetermined time.
Reference numeral 49 denotes a readable and erasable storage device (hereinafter, referred to as RAM) for storing the temperature detected by each temperature detector.

In the ROM 46, an actual logarithmic average temperature difference Tem is calculated from the chilled water inlet temperature T1, the chilled water outlet temperature T2, and the refrigerant temperature T3.

[0013]

(Equation 1)

And 1 during normal operation of the absorption refrigerator.
A program for calculating the chilled water load from the difference between the chilled water inlet temperature and the chilled water outlet temperature at the time of the 00% load and the actually detected difference between the chilled water inlet temperature and the chilled water outlet temperature, and the chilled water load and the logarithmic average temperature shown in FIG. The relationship with the difference is stored. In FIG. 3, A is an ideal line indicating the relationship between the chilled water load and the logarithmic average temperature difference when the absorption refrigerator is operating normally, and B is an abnormal line that outputs an abnormal signal.

During the operation of supplying cold water of the absorption refrigerator, the refrigerant evaporated in the high-temperature regenerator 4 flows to the condenser 7 through the low-temperature regenerator 6 as in the conventional absorption refrigerator, and the heat exchanger is connected to the condenser. After being condensed and liquefied by exchanging heat with the cooling water flowing through 27, it flows to the evaporator 1 via the refrigerant pipe 18. Then, the refrigerant exchanges heat with water flowing through the evaporator heat exchanger 24 to evaporate, and the water flowing through the evaporator heat exchanger 24 is cooled by heat of vaporization.
Then, cold water circulates through the load. Further, the refrigerant evaporated in the evaporator 1 is absorbed by the absorbing liquid in the absorber 2. The absorption liquid whose concentration has been reduced by absorbing the refrigerant is sent to the high-temperature regenerator 4 via the low-temperature heat exchanger 9 and the high-temperature heat exchanger 10 by the operation of the absorption liquid pump 16. The absorbing liquid sent to the high-temperature regenerator 4 is heated by the burner 5 to evaporate the refrigerant, and the medium-density absorbing liquid flows through the high-temperature heat exchanger 10 to the low-temperature regenerator 6. In the low-temperature regenerator 6, the absorbing liquid is heated by the refrigerant vapor flowing from the high-temperature regenerator 10 through the refrigerant pipe 17, and the refrigerant vapor is further separated to increase the concentration. The high-concentration absorbent is cooled down through the low-temperature heat exchanger 9 and sent to the absorber 2 where it is dispersed.

As described above, abnormality detection when the absorption refrigerator is in operation will be described with reference to the flowchart of FIG. The temperatures detected by the first and second temperature detectors 36 and 37 and the refrigerant temperature detector 38 are temporarily stored in the RAM 49 via the input interface 44 and the CPU 45. Then, the chilled water inlet temperature, chilled water outlet temperature and refrigerant temperature stored in the RAM 49 are read into the CPU 45 at predetermined time intervals based on a signal from the CLOCK 48, and the above equation (1), the program and the logarithm of the chilled water load are read from the ROM 46. The relationship with the average temperature difference is read. Then, the load (%) is calculated from the actual chilled water inlet / outlet temperature difference and the chilled water inlet / outlet temperature difference (5 ° C.) when the load is 100%. Here, for example, when the cold water inlet temperature is 10 ° C., the cold water outlet temperature is 7 ° C., and the temperature difference is 3 ° C., the load is 3 ° C.
/5=0.6 (60%).

Further, the CPU 45 calculates the actual logarithmic average temperature difference Tem from the chilled water inlet temperature, the chilled water outlet temperature, the refrigerant temperature and the equation (1). Here, for example, the cooling performance of the evaporator 1 is reduced due to contamination of the evaporator heat exchanger 24 and the like, so that the chilled water inlet temperature is 10 ° C. and the chilled water outlet temperature is 7 ° C.
When the refrigerant temperature is, for example, 4.3 ° C., the actual logarithmic average temperature difference is approximately 4.5 ° C. Since the logarithmic average temperature difference is higher than the value (4.0 ° C.) when the load of the abnormal line is 60% shown in FIG.
An abnormal signal is output via the face 47 and the abnormal detector 4
From 0, an abnormal signal is output to the notification device 41. And
ALARM is displayed on the display device 42 of the notification device 41, and the buzzer 43 sounds to notify the abnormality of the evaporator 1.

When the chilled water load is, for example, 60%, the actual logarithmic average temperature difference Tem calculated from the chilled water inlet temperature, the chilled water outlet temperature, the refrigerant temperature and the equation (1) is, for example, 3.
When the temperature is 5 ° C. and is lower than the value (4.0 ° C.) on the abnormal line when the load is 60%, the CPU 45 does not output the abnormal signal, and the notifying device 41 does not notify the abnormality. According to the above embodiment, the abnormality detector 40 calculates the actual logarithmic average temperature difference based on the chilled water inlet temperature, the chilled water outlet temperature, and the refrigerant temperature. If the abnormality exceeds the previously stored abnormality line, the abnormality detector 40 outputs a signal. Therefore, even if an abnormality occurs in the evaporator 1 even in an intermediate period other than summer or winter, an absorption type An abnormality can be detected at the initial stage of occurrence of an abnormality by detecting an abnormality at the time of partial load of the chiller / heater, and as a result, maintenance and inspection of the absorption chiller / heater can be performed more reliably. In the above embodiment, the refrigerant temperature detector 38 is connected to the refrigerant pump 2.
Although the refrigerant temperature detector 38 is provided in the refrigerant pipe 18 on the inlet side of the refrigerant pipe 0, the refrigerant temperature detector 38 may be provided in a refrigerant circulation path including the evaporator heat exchanger 24, the refrigerant reservoir 29, the refrigerant pump 20, and the refrigerant pipe 18. When the refrigerant temperature of the refrigerant pipe 18 on the inlet side of the refrigerant pump 20 is detected, the detected refrigerant temperature is closer to the saturation temperature of the evaporator 1 than when the refrigerant temperature on the outlet side is detected. The logarithmic average temperature difference can be calculated more accurately, and when the refrigerant temperature detector 38 is provided in the refrigerant reservoir 29, the detected refrigerant temperature becomes closer to the saturation temperature of the evaporator 1, and the actual logarithmic average The temperature difference can be calculated more accurately. Further, even when the refrigerant temperature detector 38 detects the refrigerant distribution temperature of the evaporator 1, the actual logarithmic average temperature difference can be accurately calculated.

Hereinafter, a second embodiment of the present invention will be described. It should be noted that a configuration that is not particularly described is the same as the above-described embodiment, and a detailed description is omitted. Reference numeral 45 denotes a pressure detector for detecting the pressure in the evaporator 1. In this embodiment, the relationship between the pressure of the evaporator 1 and the saturation temperature is stored in the ROM 46 of the abnormality detector 40. Then, the pressure in the evaporator 1 is detected by the pressure detector 45 to determine the saturation temperature, and the saturation temperature is substituted into the equation 1 instead of the refrigerant temperature to calculate the actual temperature from the inlet temperature, the chilled water outlet temperature and the saturation temperature. The logarithmic average temperature difference is calculated, and when this value exceeds the abnormal line, the abnormality detecting device 40 outputs an abnormal signal.

By obtaining the actual logarithmic mean temperature difference using the saturation temperature as in the above embodiment, the logarithmic mean temperature difference can be accurately calculated according to the saturation temperature. Anomalies can be more accurately detected before they occur. Further, as shown in the above embodiment, the actual logarithmic average temperature difference is obtained, the ratio of the chilled water load to the logarithmic average temperature difference is calculated, and when this ratio exceeds a predetermined value, the abnormality detection device 40 In this case, the same operation and effect as in the above embodiment can be obtained.

Further, an actual logarithmic average temperature difference is calculated from the chilled water inlet temperature, the chilled water outlet temperature and the refrigerant temperature or the saturation temperature, and a ratio of this value to the ideal logarithmic average temperature difference is calculated. Then, when this ratio exceeds a predetermined value, the abnormality detector 40 outputs an abnormality signal. For example, when the load is 60%, the actual log average temperature difference is 4.5 ° C., and the ideal log average temperature difference is 3.2 ° C., the above ratio is 4.5 / 3.2 = 1.
4, when it is larger than a predetermined value (for example, 1.25), the abnormality detector 40 outputs an abnormality signal. Further, the actual heat transmission coefficient which is the reciprocal of the above ratio is calculated, and when the heat transmission coefficient becomes a predetermined value (for example, 80%) or less, the abnormality detector 40 outputs an abnormality signal. Can obtain the same effect.

Although the above embodiment has been described based on the absorption type chiller / heater which can supply cold water or hot water, the absorption type chiller which supplies only cold water may be provided with the abnormality detector similarly to the above embodiment. Thereby, the same operation and effect can be obtained.

[0023]

According to the present invention, there is provided an abnormality detecting device for an absorption refrigerator configured as in the above embodiment, in which a chilled water temperature detector detects a chilled water inlet temperature and an outlet temperature of an evaporator, respectively.
A refrigerant temperature detector detects the refrigerant temperature of the refrigerant circuit having the refrigerant pump, and the abnormality detector calculates a chilled water load from a difference between the detected temperatures of the chilled water temperature detectors and a chilled water inlet / outlet temperature difference at 100% load. And, the actual logarithmic average temperature difference of the evaporator is calculated from the detected temperatures of each chilled water temperature detector and the refrigerant temperature detector, and the actual logarithmic average temperature difference is compared with the chilled water load to output an abnormal signal. For example, abnormalities in the evaporator can be reliably detected even during a partial load in the interim period other than summer, as a result, maintenance and inspection of the absorption chiller can be performed early to avoid the suspension of the absorption chiller. can do.

Also, the temperature of the cold water inlet and the outlet of the evaporator are detected, and the pressure inside the evaporator is detected to determine the saturation temperature.
The actual logarithmic average temperature difference of the evaporator is calculated from the chilled water inlet / outlet temperature and the saturation temperature, and the actual logarithmic average temperature difference is compared with the chilled water load to output an abnormal signal. An abnormality in the evaporator can be reliably detected before a change occurs.

Further, the temperature of the chilled water inlet and the temperature of the outlet of the evaporator are detected, the temperature of the refrigerant in the refrigerant circuit having the refrigerant pump is detected, and the abnormality detector detects the chilled water load and the ideal logarithmic average when the evaporator is sound. The relationship with the temperature difference is stored, the chilled water load is calculated, and the ideal logarithmic average temperature difference corresponding to the chilled water load is obtained from the relationship between the chilled water load and the ideal logarithmic average temperature difference, and from each detected temperature. The actual log-average temperature difference of the evaporator is calculated, and the actual log-average temperature difference is compared with the ideal log-average temperature difference. If the ratio of the actual log-average temperature difference to the ideal log-average temperature difference is equal to or more than a predetermined value, an abnormal signal is output. Output, it is possible to reliably distinguish between a change in chilled water temperature due to a load change and the occurrence of an abnormality and to detect an abnormality. As a result, the maintenance and inspection work of the absorption chiller can be performed more accurately. so That.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an absorption refrigerator showing one embodiment of the present invention.

FIG. 2 is a block diagram of an anomaly detector.

FIG. 3 is a relationship diagram between a load and a logarithmic average temperature difference.

FIG. 4 is a flowchart illustrating the operation of the abnormality detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 2 Absorber 4 High temperature regenerator 6 Low temperature regenerator 9 Low temperature heat exchanger 10 High temperature heat exchanger 20 Refrigerant pump 36 Cold water temperature detector 37 Cold water temperature detector 38 Refrigerant temperature detector 40 Abnormality detector

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 49/04

Claims (3)

(57) [Claims] 1. An absorption refrigerator in which a regenerator, a condenser, an evaporator, an absorber and the like are connected by pipes, a chilled water temperature detector for detecting a chilled water inlet temperature and an outlet temperature of the evaporator, and an evaporator. The temperature difference between the refrigerant temperature detectors for detecting the refrigerant temperature of the refrigerant circuit of
The chilled water load is calculated from the chilled water inlet / outlet temperature difference at the time of 0% load, and the actual logarithmic average temperature difference of the evaporator is calculated from the detected temperature of each chilled water temperature detector and the refrigerant temperature detector. An abnormality detector for comparing the difference with the chilled water load and outputting an abnormality signal; 2. An absorption refrigerator comprising a regenerator, a condenser, an evaporator, an absorber and the like connected by piping, a chilled water temperature detector for detecting a chilled water inlet temperature and an outlet temperature of the evaporator, and an evaporator. A pressure detector that detects the internal pressure, a saturation temperature is determined from the pressure detected by the pressure detector, an actual logarithmic average temperature difference is calculated from the saturation temperature and the detection temperature of each chilled water temperature detector, and An abnormality detector that calculates a chilled water load from a difference between the detected temperatures of the chilled water temperature detectors and a chilled water inlet / outlet temperature difference at a 100% load, compares the chilled water load with an actual logarithmic average temperature difference, and outputs an abnormality signal. An abnormality detection device for an absorption refrigerator, comprising: 3. An absorption refrigerator including a regenerator, a condenser, an evaporator, an absorber and the like connected by piping, a chilled water temperature detector for detecting a chilled water inlet temperature and an outlet temperature of the evaporator, and an evaporator. A refrigerant temperature detector that detects the refrigerant temperature of the refrigerant circulation path, and a relationship between the chilled water load and the ideal logarithmic average temperature difference when the evaporator is healthy are stored, and the difference between the detected temperatures of the respective chilled water temperature detectors is stored. And the chilled water inlet / outlet temperature difference at the time of 100% load, the chilled water load is calculated, the ideal logarithmic mean temperature difference corresponding to the chilled water load is obtained from the relationship between the chilled water load and the ideal logarithmic mean temperature difference, and Calculate the actual log average temperature difference of the evaporator from the detected temperatures of the detector and the refrigerant temperature detector, compare the actual log average temperature difference with the ideal log average temperature difference, and calculate the actual log average temperature for the ideal log average temperature difference. The difference ratio is less than the specified value An abnormality detector for an absorption refrigerator comprising: an abnormality detector that outputs an abnormality signal in the above case.