WO2023153421A1

WO2023153421A1 - Remote monitoring system for absorption refrigerator

Info

Publication number: WO2023153421A1
Application number: PCT/JP2023/004139
Authority: WO
Inventors: 修司石崎; 佑太増渕
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2022-02-08
Filing date: 2023-02-08
Publication date: 2023-08-17
Also published as: JP2023115746A

Abstract

According to the present disclosure, a remote monitoring system for an absorption refrigerator is provided which can continuously monitor COP decrease and, if COP has decreased, implement control for improving COP.　The present invention: comprises an absorption refrigerator 100 that comprises a high-temperature regenerator 5, a low-temperature regenerator 6, an evaporator 1, a condenser 7, and an absorber 3, and that is formed by connecting these using piping and respectively forming circulation paths for an absorbent and a refrigerant; and comprises a server-purpose control unit 57 that implements COP improvement response control which changes a driving frequency of a diluted absorbent pump 45 if it is determined that COP is decreasing. If it is determined that the COP after the COP improvement response control has worsened compared to the COP before the COP improvement response control, the server-purpose control unit 57 stops the COP improvement response control and controls the driving frequency of the diluted absorbent pump 45 so as to return said frequency to before.

Description

Absorption Chiller Remote Monitoring System

The present invention relates to a remote monitoring system for an absorption chiller, and more particularly to a remote monitoring system for an absorption chiller that accurately determines a decrease in heat exchange efficiency in a condenser.

In Patent Document 1, a control device detects whether a difference between a cold water set temperature and a cold water outlet temperature, which are stable conditions, is within a predetermined range in the vicinity of a plurality of cooling loads, and whether the cooling water outlet temperature is within a predetermined range. If the assumed concentrated liquid concentration is lower than a predetermined value when the stable condition continues for a predetermined period of time, the absorption chiller performs a correction process to reduce the inverter frequency of the dilute absorbent pump. Disclose.
Patent document 2 calculates the COP during cooling operation, calculates the COP increase/decrease rate from the calculated COP and the assumed COP, and determines that the average COP increase/decrease rate for one month is equal to or less than a predetermined value. , an absorption chiller equipped with a control device for issuing a maintenance instruction forecast.

JP 2019-190708 A JP 2018-169075 A

The present disclosure provides a remote monitoring system for an absorption chiller that can constantly monitor the COP drop and perform control to improve the COP when the COP drops.

In order to achieve the above object, the remote monitoring system for an absorption chiller of the present disclosure comprises a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, which are connected by piping to monitor absorption liquid and refrigerant. Absorption refrigerators each forming a circulation path are provided, and when it is determined that the COP is lowered, a control unit is provided to perform control for improving the COP by changing the driving frequency of the dilute absorbent pump, wherein the control unit When it is determined that the COP after the COP-improvement control is worse than the COP before the COP-improvement control, the COP-improvement control is stopped and the drive frequency of the dilute absorbent pump is restored. do.
This specification includes all the contents of Japanese Patent Application No. 2022-018140 filed in Japan on February 8, 2022.

According to the present disclosure, when the control unit performs COP improvement control for improving the COP when the COP has decreased, and determines that the COP after the COP improvement control is worse than the COP before the COP improvement control In addition, by stopping the control for improving the COP and controlling it so that the drive frequency of the dilute absorbent pump is restored, the effect of the control for improving the COP can be confirmed and safety can be ensured. .

FIG. 1 is a schematic configuration diagram of an absorption chiller according to Embodiment 1. FIG. 2 is a block diagram showing a control configuration according to Embodiment 1; FIG. 3 is a flowchart showing the operation of the first embodiment; FIG. 4 is a graph showing the relationship between cold water flow rate and cold water flow rate output FIG. 5 is a graph showing the relationship between the gas flow rate and the opening degree of the gas fuel valve FIG. 6 is an explanatory diagram showing the process of cause analysis processing

(Knowledge, etc. on which the invention is based)
At the time when the inventors came up with the present disclosure, there was a technique in an absorption chiller for judging the COP based on the concentration of the absorbent during stable operation and for monitoring the rate of increase or decrease of the COP every month. Ta.
However, in such an absorption chiller, the COP reduction is not always monitored, and when the COP is reduced, the cause of the COP reduction is analyzed and the COP improvement control based on this analysis is systemized. We have discovered the problem that it is impossible to do so, and have come to constitute the subject matter of the present disclosure in order to solve the problem.
Accordingly, the present disclosure provides a remote monitoring system for an absorption chiller that can constantly monitor the decrease in COP and perform control to improve the COP when the COP has decreased.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially the same configurations may be omitted. This is to avoid the following description from becoming more redundant than necessary and to facilitate understanding by those skilled in the art.
It should be noted that the accompanying drawings and the following description are provided to allow those skilled in the art to fully understand the present disclosure and are not intended to limit the claimed subject matter thereby.

(Embodiment 1)
Embodiment 1 will be described below with reference to the drawings.
[1-1. composition]
[1-1-1. Configuration of Absorption Chiller]
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an absorption chiller according to this embodiment. The absorption chiller 100 uses water as a refrigerant and a lithium bromide (LiBr) aqueous solution as an absorption liquid.

As shown in FIG. 1, the absorption refrigerator 100 includes an evaporator 1, an absorber 2 arranged in parallel with the evaporator 1, and an evaporator absorber barrel 3 housing the evaporator 1 and the absorber 2. , a high-temperature regenerator 5 equipped with a gas burner (heating means) 4, a low-temperature regenerator 6, a condenser 7 arranged in parallel with this low-temperature regenerator 6, and these low-temperature regenerator 6 and condenser 7 are housed. and a cold regenerator condenser barrel 8 .
The absorption refrigerator 100 includes a low temperature heat exchanger 12, a high temperature heat exchanger 13, a refrigerant drain heat recovery device 17, a dilute absorbent pump 45, a rich absorbent pump 47, and a refrigerant pump 48. These devices are pipe-connected via absorption liquid pipes 21 to 25 and refrigerant pipes 31 to 35 to form a circulation path.

The evaporator 1 is provided with a cold water pipe 14 for circulating and supplying the brine heat-exchanged with the refrigerant in the evaporator 1 to a heat load (for example, an air conditioner) not shown. A partially formed heat transfer tube 14A is arranged in the evaporator 1 .
The absorber 2 and the condenser 7 are provided with cooling water pipes 15 for passing cooling water through the absorber 2 and the condenser 7 in sequence. , 15B are arranged in the absorber 2 and the condenser 7 respectively.

The absorber 2 has the function of absorbing the refrigerant vapor evaporated in the evaporator 1 into the absorbing liquid and keeping the pressure inside the evaporator absorber barrel 3 in a high vacuum state. In the lower part of the absorber 2, a dilute absorbent reservoir 2A is formed in which the dilute absorbent diluted by absorbing the refrigerant vapor is stored. One end of the liquid pipe 21 is connected. The dilute absorbent pipe 21 is provided with a branched dilute absorbent pipe 21 A that branches downstream of the dilute absorbent pump 45 .
After passing through the refrigerant drain heat recovery device 17, the branched dilute absorbent pipe 21A joins the dilute absorbent pipe 21 again on the downstream side of the low temperature heat exchanger 12 of the dilute absorbent pipe 21. The other end of the dilute absorbent pipe 21 passes through the high-temperature heat exchanger 13 and is open to the air layer portion 5B located above the heat exchange portion 5A formed in the high-temperature regenerator 5 .
The dilute absorbent pipe 21 is branched into a second branch pipe 21B on the downstream side of the low temperature heat exchanger 12, and the second branch pipe 21B opens into the low temperature regenerator 6.

The high-temperature regenerator 5 is configured by housing a gas burner 4 in a shell 60, and above the gas burner 4, a heat exchange section 5A is formed to heat and regenerate the absorbent using the flame of the gas burner 4 as a heat source. An exhaust path 40 through which exhaust gas burned by the gas burner 4 flows is connected to the heat exchange section 5A, and an exhaust gas heat exchanger 41 is provided in the exhaust path 40 . A gas pipe 61 supplied with fuel gas and an intake pipe 63 supplied with air from a blower 62 are connected to the gas burner 4. Fuel gas and air are connected to these gas pipe 61 and intake pipe 63. A control valve 64 is provided to control the amount of

Formed on the side of the heat exchanging portion 5A is an intermediate absorbent reservoir 5C in which the intermediate absorbent flowing out of the heat exchanging portion 5A after being thermally regenerated in the heat exchanging portion 5A is accumulated. One end of a second intermediate absorbent pipe 23 is connected to the lower end of the intermediate absorbent reservoir 5C, and the second intermediate absorbent pipe 23 is provided with a high-temperature heat exchanger 13 . The high-temperature heat exchanger 13 heats the absorbent flowing through the first intermediate absorbent tube 22 with the heat of the high-temperature intermediate absorbent flowing out of the intermediate absorbent reservoir 5C. We are trying to reduce fuel consumption.
The other end of the second intermediate absorbent pipe 23 is connected to a rich absorbent pipe 25 that connects the low temperature regenerator 6 and the absorber 2 . The upstream side of the high-temperature heat exchanger 13 of the second intermediate absorbent pipe 23 and the absorber 2 are connected by an absorbent pipe 24 with an on-off valve V1 interposed therebetween.

The low-temperature regenerator 6 uses the refrigerant vapor separated by the high-temperature regenerator 5 as a heat source to heat and regenerate the absorbent accumulated in the absorbent reservoir 6A formed in the low-temperature regenerator 6. , a heat transfer pipe 31A formed in a part of the refrigerant pipe 31 extending from the upper end of the high temperature regenerator 5 to the bottom of the low temperature regenerator 6 is arranged. By circulating the refrigerant vapor through the refrigerant pipe 31, the heat of the refrigerant vapor is transmitted to the absorbent accumulated in the absorbent reservoir 6A via the heat transfer pipe 31A, and the absorbent is further concentrated.
One end of a concentrated absorbent pipe 25 is connected to the absorbent reservoir 6A of the low-temperature regenerator 6, and the other end of the concentrated absorbent pipe 25 is connected to a concentrated solution sprayer provided above the air layer portion 2B of the absorber 2. 2C is connected. A concentrated absorbent pump 47 and a low temperature heat exchanger 12 are provided in the concentrated absorbent pipe 25 . The low-temperature heat exchanger 12 heats the dilute absorbent flowing through the dilute absorbent tube 21 with the heat of the concentrated absorbent flowing out of the absorbent reservoir 6B of the low-temperature regenerator 6 .

A bypass pipe 27 that bypasses the concentrated absorbent pump 47 and the low-temperature heat exchanger 12 is provided in the concentrated absorbent pipe 25 .
When the operation of the concentrated absorbent pump 47 is stopped, the absorbent accumulated in the absorbent reservoir 6A of the low temperature regenerator 6 is supplied into the absorber 2 through the concentrated absorbent pipe 25 and the bypass pipe 27 .

As described above, the gas layer portion 5B of the high-temperature regenerator 5 and the refrigerant liquid reservoir 7A formed at the bottom of the condenser 7 are connected by the refrigerant pipe 31 . The refrigerant pipe 31 includes a heat transfer pipe 31A connected to the absorbent reservoir 6A of the low-temperature regenerator 6 and a refrigerant drain heat recovery device 17. It is connected to the portion 2B by a refrigerant pipe 32 in which an on-off valve V2 is interposed.
One end of a refrigerant pipe 34 through which the refrigerant flowing out from the refrigerant reservoir 7A flows is connected to the refrigerant reservoir 7A of the condenser 7, and the other end of the refrigerant pipe 34 is a downwardly curved U-seal portion 34A. is connected to the gas layer portion 1A of the evaporator 1 via the .
Below the evaporator 1, a refrigerant reservoir 1B in which liquefied refrigerant is accumulated is formed. It is connected by a refrigerant pipe 35 in between.

The cooling water pipe 15 is provided with a cooling water inlet temperature sensor 36 for detecting the temperature of the cooling water flowing through the cooling water pipe 15 on the inlet side and a cooling water outlet temperature sensor 37 for detecting the temperature on the cooling water outlet side. there is
The cold water pipe 14 is provided with a cold water inlet temperature sensor 38 for detecting the temperature of the cold water flowing through the cold water pipe 14 on the inlet side and a cold water outlet temperature sensor 39 for detecting the temperature on the cold water outlet side.

The absorption chiller 100 of this embodiment also includes an air bleeder 70 , and the air bleeder 70 includes a tank 71 . An air bleed pipe 52 communicating with the air layer portion 2B of the absorber 2 is connected to the upper portion of the tank 71 . A return pipe 73 that communicates with the bottom of the absorber 2 is connected to the bottom of the tank 71 . Furthermore, an absorbent pipe 75 connected to the dilute absorbent pipe 21 via an ejector pump 74 is connected to the upper portion of the tank 71 .
By driving the ejector pump 74 , the dilute absorbent in the dilute absorbent tube 21 is taken into the tank 71 through the absorbent tube 75 . The dilute absorbent flowing through the absorbent pipe 75 creates a negative pressure inside the tank 71, thereby extracting not only the non-condensable gas stored in the upper part of the absorber 2 but also the refrigerant vapor and vaporized absorbent. It is guided above the tank 51 through the trachea 72 .

Of the gas led to the tank 71, the refrigerant vapor and the vaporized absorbing liquid dissolve and are absorbed by the absorbing liquid accumulated in the lower part of the tank 71, but the noncondensable gas cannot dissolve in the absorbing liquid. It is stored above the tank 71 . Then, the absorbent accumulated in the lower part of the tank 71 is returned to the absorber 3 through the return pipe 73 .

[1-1-2. control configuration]
Next, the control configuration of this embodiment will be described.
FIG. 2 is a block diagram showing the control configuration of this embodiment.
As shown in FIG. 2 , the absorption chiller 100 of this embodiment includes a controller 50 , and the controller 50 includes a refrigerator controller 51 . The refrigerator controller 51 centrally controls each part of the absorption chiller 100, and stores a CPU as an arithmetic execution unit, a basic control program executable by the CPU, predetermined data, and the like in a non-volatile manner. A memory such as a ROM and a RAM for storing data and other peripheral circuits are provided.
Further, detection signals from the cooling water inlet temperature sensor 36, the cooling water outlet temperature sensor 37, the cold water inlet temperature sensor 38, and the cold water outlet temperature sensor 39 are input to the refrigerator controller 51, respectively. .

The refrigerator control unit 51 of the controller 50 controls the fuel control valve 64 of the gas burner 4 of the absorption refrigerator 100 to control the combustion by the gas burner 4, and the dilute absorbent pump 45 and the rich absorbent pump 47. and drive control of the refrigerant pump 48 . Furthermore, the refrigerator control unit 51 of the controller 50 performs inverter control of the dilute absorbent pump 45, the rich absorbent pump 47 and the refrigerant pump 48, so that the dilute absorbent pump 45, the intermediate absorbent pump 46, the rich absorbent It is configured to perform flow rate control by the liquid pump 47 and the refrigerant pump 48 . Further, the refrigerator controller 51 is configured to control the opening and closing of the valves 28, V1 and V2.

Further, a cloud adapter 52 is connected to the controller 50 , and various refrigerator data acquired by the refrigerator controller 51 of the controller 50 are sent to the cloud adapter 52 .
The cloud adapter 52 includes an adapter control unit 53. The adapter control unit 53 includes a CPU as an arithmetic execution unit, and a ROM that nonvolatilely stores a basic control program that can be executed by this CPU, predetermined data, and the like. , memory such as RAM, and other peripheral circuits.
Here, the refrigerator data includes, for example, cold water inlet temperature, cold water outlet temperature, high temperature regenerator temperature, condensing temperature, cooling water inlet temperature, cooling water outlet temperature, absorbent temperature, absorbent concentration, refrigerant temperature, control valve Various data such as the degree of opening are included.
The cloud adapter 52 includes an adapter communication unit 54 that communicates with the cloud server 56 of the cloud 55 .

The cloud server 56 includes a server control unit 57. The server control unit 57 includes a CPU as an arithmetic execution unit, and a ROM that nonvolatilely stores a basic control program executable by this CPU, predetermined data, and the like. , memory such as RAM, and other peripheral circuits.
In the present embodiment, the server controller 57 functions as the controller of the present disclosure.
The cloud server 56 includes a server communication unit 58 that communicates with the cloud adapter 52 .
The server control unit 57 of the cloud server 56 acquires the refrigerator data sent from the cloud adapter 52 by the server communication unit 58, and based on this refrigerator data, judges the COP decrease, analyzes the cause of the COP decrease, and determines the COP. It is configured to take measures to improve it.

[1-2. motion]
Next, the operation of this embodiment will be described.
During a cooling operation such as cooling, brine (for example, cold water) is circulated and supplied to a heat load (not shown) through the cold water pipe 14 . The refrigerator control unit 51 puts the brine into the absorption refrigerator 100 so that the outlet side temperature of the brine evaporator 1 (the temperature detected by the cold water outlet temperature sensor 39) becomes a predetermined set temperature, for example, 7°C. The amount of heat applied is controlled.
Specifically, the refrigerator controller 51 activates all the

pumps

45, 47, and 48 and controls the combustion of the gas in the gas burner 4 so that the brine temperature measured by the cold water outlet temperature sensor 39 is controlled to a predetermined 7°C.

In this case, the lean absorbent from the absorber 2 is heated by the lean absorbent pump 45 via the lean absorbent tube 21 via the low temperature heat exchanger 12 and the high temperature heat exchanger 13 or the exhaust gas heat exchanger 41. It is sent to the high temperature regenerator 5 .
The absorbent sent to the high-temperature regenerator 5 is heated by the flame from the gas burner 4 and the high-temperature combustion gas in the high-temperature regenerator 5, so that the refrigerant in the absorbent evaporates and separates. The intermediate absorbent whose concentration has increased by evaporating and separating the refrigerant in the high-temperature regenerator 5 is sent to the concentrated absorbent pipe 25 via the high-temperature heat exchanger 13 and joins the absorbent that has passed through the low-temperature regenerator 6. .

On the other hand, the absorbent sent to the low-temperature regenerator 6 is heated by the high-temperature refrigerant vapor that is supplied from the high-temperature regenerator 5 through the refrigerant pipe 31 and flows into the heat transfer pipe 31A. This concentrated absorbent is combined with the absorbent that has passed through the high-temperature regenerator 5, and is sent to the absorber 2 via the low-temperature heat exchanger 12 by the concentrated absorbent pump 47, whereupon it is sent to the concentrated liquid sprayer 2C. distributed from.

The refrigerant separated and produced by the low-temperature regenerator 6 enters the condenser 7, is condensed, and accumulates in the refrigerant liquid reservoir 7A. When a large amount of refrigerant liquid accumulates in the refrigerant liquid reservoir 7A, this refrigerant liquid flows out from the refrigerant liquid reservoir 7A, enters the evaporator 1 via the refrigerant pipe 34, is pumped by the operation of the refrigerant pump 48, and is dispersed. It is sprayed from the vessel 1C onto the heat transfer tubes 14A of the cold water tubes 14.
Since the refrigerant liquid sprayed over the heat transfer tubes 14A takes heat of vaporization from the brine passing through the heat transfer tubes 14A and evaporates, the brine passing through the heat transfer tubes 14A is cooled, and the brine whose temperature has been lowered in this way is Cooling operation such as cooling is performed by supplying the heat load from the cold water pipe 14 .
The refrigerant evaporated in the evaporator 1 enters the absorber 2 and is absorbed by the concentrated absorbent supplied from the low-temperature regenerator 6 and sprayed from above. The circulation of the absorbent pump 45 to the high-temperature regenerator 5 is repeated.

Next, control according to this embodiment will be described with reference to the flowchart shown in FIG.
FIG. 3 is a flow chart showing the operation of this embodiment.
In the present embodiment, the adapter controller 53 acquires stabilized refrigerator data (ST1), and calculates the current COP while the absorption refrigerator 100 is operating in cooling operation or heating operation. (ST2).
The current COP is obtained by COP=refrigerating capacity÷gas combustion heat quantity.
The refrigerating capacity is obtained by (chilled water inlet temperature - chilled water outlet temperature) x chilled water flow rate.
The chilled water inlet temperature can be obtained by a chilled water inlet temperature sensor 38 and the chilled water outlet temperature can be obtained by a chilled water outlet temperature sensor 39 .

FIG. 4 is a graph showing the relationship between cold water flow rate and cold water flow rate output.
This graph is generated in advance by a worker performing measurement using a differential pressure sensor when the absorption chiller 100 is installed.
The cold water flow rate output can be obtained by providing a cold water differential pressure sensor, but in the present embodiment, the graph shown in FIG. 4 is used to measure the cold water flow rate output. Calculate the flow rate.
The chilled water flow rate output can be obtained by monitoring the control state of the absorption chiller 100, for example. The chilled water flow rate output may be acquired by any one of the refrigerator controller, the adapter controller 53 , and the server controller 57 .

By acquiring the cold water inlet temperature and the cold water outlet temperature from the cold water inlet temperature sensor 38 and the cold water outlet temperature sensor 39 in this manner and obtaining the cold water flow rate using the graph, the refrigeration capacity can be increased without providing a cold water differential pressure sensor. can be calculated. A cold water differential pressure sensor may be provided to calculate the refrigerating capacity.

Next, the gas combustion calorie is obtained by gas combustion calorie=unit gas calorific value×gas flow rate.
FIG. 5 is a graph showing the relationship between the gas flow rate and the degree of opening of the gas fuel valve.
This graph is generated in advance by a worker performing measurement using a gas flow meter when the absorption chiller 100 is installed.
The opening degree of the gas fuel valve can be acquired by monitoring the control state of the absorption chiller 100, for example. The degree of opening of the gas fuel valve may be acquired by any one of the refrigerator controller, the adapter controller 53 , and the server controller 57 .
The unit gas calorific value is a predetermined value. By calculating the gas flow rate from the graph based on the degree of opening of the gas fuel valve, the gas combustion heat quantity can be calculated without providing a gas flow meter. A gas flow meter may be provided to calculate the gas combustion heat quantity.
If the refrigerating capacity and the gas combustion heat quantity can be calculated, the current COP can be obtained.

The adapter control unit transmits the calculated current COP information to the cloud server 56 (ST3).
The server control unit 57 of the cloud server 56 compares the current COP sent from the cloud adapter 52 with the assumed COP serving as a reference to obtain the deviation between the current COP and the assumed COP (ST4), and the COP decreases. It is determined whether or not (ST5).
The server control unit 57 determines that the COP is normal if the deviation between the current COP and the assumed COP is within a predetermined threshold. On the other hand, when the COP deviation is higher than the predetermined threshold value, it is determined that the COP has decreased.
The server control unit 57 obtains the deviation between the current COP and the assumed COP a plurality of times (for example, 10 times) while the operation state of the absorption chiller 100 is stable, and determines the difference between the current COP and the assumed COP. If the deviation is higher than, for example, 10%, it is determined that the COP is declining.
When the server control unit 57 determines that the COP has decreased, it performs cause analysis processing (ST6).

FIG. 6 is an explanatory diagram showing the steps of the cause analysis process.
As shown in FIG. 6, the cause analysis processing performed by the server control unit 57 includes: cooling water contamination determination, vacuum degree decrease determination, cold water hunting tendency determination, high-temperature regenerator liquid level start/stop tendency determination, combustion start/stop tendency determination , high cooling water temperature determination, extraction performance inspection, and high temperature regenerator temperature rise tendency determination are performed.
The order of each process of these cause analysis processes is not limited to the order shown in FIG. 6, and may be performed in any order or simultaneously.

In the cooling water contamination determination, the contamination coefficient is calculated from the cooling water inlet/outlet temperature of the condenser and the condensed refrigerant temperature.
The contamination coefficient (ACOND) can be calculated by contamination coefficient=(dTc−dTc0)×100÷dTc0.
dTc and dTc0 can be calculated by the following formulas.
dTc = condensation temperature - (cooling water outlet temperature - cooling water intermediate temperature)
dTc0 = 1.0021 x (cooling water outlet temperature - cooling water intermediate temperature)
If the contamination coefficient is 90 or more, it is determined that the cooling water is contaminated.

The determination of the degree of vacuum is based on whether or not the prediction forecast of the "decrease in the degree of vacuum" of the absorption chiller 100 has been issued or not, and the prediction of the "decrease in the degree of vacuum" of the absorption chiller 100 has occurred 10 times/month in the most recent time. It is determined whether or not it has been reported, and whether or not the chamber pressure (non-condensable gas storage tank pressure) change ≧1.5 [kPa/H]. When the chamber pressure changes by 1.5 [kPa/H] or more, the change is about three times the expected change.
In such a situation, it is confirmed that the inhibitor (corrosion inhibitor) tends to be insufficient.

Cold water hunting tendency determination is to determine whether the COP has decreased due to the influence of disturbance.
Cold water hunting tendency determination is made based on whether or not the cold water outlet temperature has continued to be ±0.2° C./min or more for 60 minutes.

The high-temperature regenerator liquid level start/stop tendency determination is to determine whether the COP has decreased due to insufficient adjustment of the solution circulation amount.
The high-temperature regenerator liquid level start/stop tendency determination is made based on whether or not the liquid level starts/stops five times/hour or more for three hours.

The combustion start/stop tendency determination is to determine whether the COP has decreased due to the influence of the burner's fuel use failure or disturbance.
Combustion start/stop tendency determination is made based on whether or not combustion starts/stops twice or more per hour and the refrigerating capacity ratio of 40% or more continues for three hours.

The cooling water temperature high determination is to determine whether the COP has decreased due to insufficient performance of the cooling tower.
The high cooling water temperature determination is made based on whether or not a high cooling water temperature forecast has been issued.

The extraction performance inspection is to determine whether the COP has decreased due to insufficient collection of non-condensable gas in the extraction system.
The air bleed performance check is determined based on whether or not an alarm for the air bleed performance check has been issued.

The high-temperature regenerator temperature rise trend determination is to determine whether the COP has decreased due to an excessive rise in the temperature of the high-temperature regenerator.
The high-temperature regenerator temperature rise tendency determination is made based on whether or not the temperature of the high-temperature regenerator has reached 162° C. or higher.

When the server control unit 57 determines that any one of the causes is applicable as a result of the COP decrease cause analysis, the server control unit 57 makes a maintenance proposal based on the corresponding determination (ST10).
The maintenance proposal is made, for example, by sending a report on the operating status of the previous month at the beginning of the month to, for example, a remote monitoring center. In the report, describe the cause of COP decrease judged to be applicable. Thereby, the maintenance worker can obtain the cause of the decrease in COP and the index of the maintenance.
When the server control unit 57 determines that none of the cases apply and the cause of the COP decrease cannot be identified as a result of the COP decrease cause analysis, the server control unit 57 performs COP improvement control. (ST8).

When performing COP improvement control, the server control unit 57 obtains the deviation between the current concentration of the absorbing liquid and the assumed concentration.
The current concentration of the absorbent can be calculated by acquiring the high temperature regenerator temperature and the low temperature regenerator refrigerant outlet temperature with a temperature sensor and applying the acquired temperatures to a predetermined formula.
The server control unit 57 performs control so as to change the drive frequency of the dilute absorbent pump 45 based on the difference between the calculated current concentration of the absorbent and the assumed concentration.

　The drive frequency is controlled as follows. When the assumed density-current density=0.1 to 1.0, the driving frequency is controlled to -3 Hz. When the assumed density-current density=1.1 to 1.5, the drive frequency is controlled to -5 Hz. When the assumed density-current density=1.6 to 2.0, the driving frequency is controlled to -8 Hz. If the assumed density - current density = 2.1 or more, the inspection is instructed without changing the driving frequency.

After performing the control for improving the COP, the server control unit 57 confirms the effect of the control for improving the COP (ST9).
To check the effect, the server control unit 57 obtains the COP deviation after the COP improvement control after performing the COP improvement control, and compares it with the COP deviation before the COP improvement control.
When the COP deviation after the COP improvement control is larger than the COP deviation before the COP improvement control + 2%, that is, the COP has deteriorated even though the COP improvement control has been performed. If so, the control for improving the COP is stopped, and the drive frequency of the dilute absorbent pump 45 is restored.
After that, the server control unit 57 does not perform the COP improvement control until the absorption chiller 100 stops.

The server control unit 57 confirms the effect and takes safety measures against excessive control.
The safety measures for excessive control are either the concentrated liquid concentration calculated value of the absorbing liquid is above the first threshold (e.g., 64 wt%) or the temperature of the high-temperature regenerator is above the second threshold (e.g., 158°C). is satisfied, the control for improving the COP is stopped until the operation is stopped, and the drive frequency of the dilute absorbent pump 45 is restored.
After that, the server control unit 57 does not perform the COP improvement control until the absorption chiller 100 stops.
Note that the first threshold and the second threshold described above are set to values smaller than the condition for stopping the absorption chiller 100 . For example, the conditions for stopping the absorption chiller 100 are assuming that the concentrated liquid concentration calculated value of the absorbing liquid is 65.5 wt % or more, or the temperature of the high-temperature regenerator is 165° C. or more, the first threshold is 64 wt %, and the second threshold is 64 wt %. 2 is set to 158°C. By setting the threshold values in stages in preparation for the occurrence of an abnormality in this manner, the absorption chiller 100 first stops the COP improvement control when an abnormality occurs, and then stops when the abnormality is not resolved. can take appropriate action.

[1-3. effects, etc.]
As described above, in this embodiment, the high-temperature regenerator 5, the low-temperature regenerator 6, the evaporator 1, the condenser 7, and the absorber 3 are provided. The server control unit 57 (control unit) includes the absorption chiller 100 formed respectively, and performs control for improving the COP by changing the drive frequency of the dilute absorbent pump 45 when it is determined that the COP has decreased. When the server control unit 57 determines that the COP after the COP improvement control is worse than the COP before the COP improvement control, the server control unit 57 stops the COP improvement control and drives the dilute absorbent pump 45. Control to restore the frequency.
According to this, when the COP is reduced, the control unit performs the COP improvement control for improving the COP, and when it is determined that the COP after the COP improvement control is worse than the COP before the COP improvement control. By stopping the COP improvement control and restoring the drive frequency of the dilute absorbent pump 45, the effect of the COP improvement control can be confirmed and safety can be ensured. .

Further, in the present embodiment, a high-temperature regenerator 5, a low-temperature regenerator 6, an evaporator 1, a condenser 7 and an absorber 3 are provided, and these are connected by piping to form circulation paths for the absorbent and the refrigerant, respectively. and a server control unit 57 (control unit) that performs control for improving the COP by changing the drive frequency of the dilute absorbent pump 45 when it is determined that the COP has decreased, When the server control unit 57 determines that the concentrated liquid concentration calculation value of the absorbent or the temperature of the high-temperature regenerator 5 has reached or exceeded a predetermined threshold value, the server control unit 57 restores the driving frequency of the weak absorbent pump 45. to control.
According to this, when the COP is lowered, the server control unit 57 performs COP improvement control for improving the COP, and the concentrated liquid concentration calculation value of the absorbent or the temperature of the high-temperature regenerator 5 is set to a predetermined threshold value. When it is determined that the above condition has been reached, the control for improving the COP is stopped and the drive frequency of the dilute absorbent pump 45 is restored to the original frequency, thereby confirming the effect of the control for improving the COP. Safety can be ensured.

Further, in the present embodiment, when the server control unit 57 (control unit) controls to restore the driving frequency of the dilute absorbent pump 45, the COP Improvement control is not implemented.
According to this, when the server control unit 57 controls to restore the drive frequency of the dilute absorbent pump 45, the COP improvement control is not performed until the absorption chiller 100 stops. , safety can be ensured when COP is not recognized to improve.

Further, in the present embodiment, when the control for improving COP is performed, the server control unit 57 (control unit) controls the dilute absorbent pump 45 based on the difference between the assumed concentration of the absorbent and the current concentration. Control is performed to change the amount of change in the driving frequency.
According to this, it is possible to perform COP improvement control according to the degree of COP decrease.

In the present embodiment, the cloud adapter 52 capable of communicating with the cloud server 56 is connected to the absorption chiller 100, and the control unit is the server control unit 57 of the cloud server 56 or the adapter control unit of the cloud adapter 52. It is part 53 .
According to this, the server control unit 57 of the cloud server 56 or the adapter control unit 53 of the cloud adapter 52 can perform analysis processing of whether or not the COP has decreased, the cause of the COP decrease, and the like.

(Other embodiments)
As described above, Embodiment 1 has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments with modifications, replacements, additions, omissions, and the like. Also, it is possible to combine the constituent elements described in the first embodiment to form a new embodiment.

Each unit shown in FIG. 2 is an example, and the specific implementation is not particularly limited. In other words, it is not always necessary to mount hardware corresponding to each part individually, and it is of course possible to adopt a configuration in which one processor executes a program to realize the function of each part. Further, part of the functions implemented by software in the above-described embodiments may be implemented by hardware, or part of the functions implemented by hardware may be implemented by software.

Further, in Embodiment 1, an example in which the server control unit 57 of the cloud server 56 is used as the control unit has been described, but the present disclosure is not limited to this. For example, the adapter controller 53 of the cloud adapter 52 may be used.
Further, the refrigerator controller may be provided with the same function as the adapter controller 53, and the refrigerator controller may be used as the controller.

In the first embodiment, the server control unit 57 compares the current COP with an assumed COP that serves as a reference, and determines whether the COP has decreased based on the deviation between the current COP and the assumed COP. However, the present disclosure is not limited to this.
For example, even if the deviation between the current COP and the assumed COP is within a predetermined threshold, if the current COP is slightly lower than the assumed COP (for example, 2%), the maintenance proposal is for the absorption chiller 100 maintenance may be proposed. At this time, COP decrease cause analysis processing and COP improvement control are not performed.

In the first embodiment, the server control unit 57 always performs COP improvement control when the cause of COP reduction cannot be identified. Whether or not to perform the control may be switched by the user, the property on which the absorption chiller 100 is installed, or the setting of the absorption chiller 100 .

The present disclosure is applicable to an absorption chiller capable of monitoring the COP drop and analyzing the cause of the COP drop when the COP drops.

1 evaporator 2 absorber 3 absorber 4 gas burner 5 high temperature regenerator 6 low temperature regenerator 7 condenser 12 low temperature heat exchanger 13 high temperature heat exchanger 14 cold water pipe 15 cooling water pipe 17 refrigerant drain heat recovery device 21 dilute absorbent pipe 36 Cooling water inlet temperature sensor 37 Cooling water outlet temperature sensor 38 Cold water inlet temperature sensor 39 Cold water outlet temperature sensor 41 Exhaust gas heat exchanger 45 Dilute absorbent pump 46 Intermediate absorbent pump 47 Concentrated absorbent pump 48 Refrigerant pump 50 Controller 51 For refrigerator Control unit 52 Cloud adapter 53 Adapter control unit 54 Adapter communication unit 55 Cloud 56 Cloud server 57 Server control unit 58 Server communication unit 64 Fuel control valve 70 Bleed device 100 Absorption chiller V1 On-off valve V2 On-off valve

Claims

An absorption chiller comprising a high-temperature regenerator, a low-temperature regenerator, an evaporator, a condenser, and an absorber, which are connected by piping to form circulation paths for the absorbing liquid and the refrigerant, respectively,
A control unit that performs control for improving the COP by changing the driving frequency of the dilute absorbent pump when it is determined that the COP has decreased,
When the control unit determines that the COP after the COP-improvement control is worse than the COP before the COP-improvement control, the control unit stops the COP-improvement control and restores the drive frequency of the dilute absorbent pump. remote monitoring system for absorption chillers.
An absorption chiller comprising a high-temperature regenerator, a low-temperature regenerator, an evaporator, a condenser, and an absorber, which are connected by piping to form circulation paths for the absorbing liquid and the refrigerant, respectively,
A control unit that performs control for improving the COP by changing the driving frequency of the dilute absorbent pump when it is determined that the COP has decreased,
When the controller determines that the concentrated solution concentration calculation value of the absorbent solution or the temperature of the high-temperature regenerator exceeds a predetermined threshold value, the controller controls the drive frequency of the weak absorbent pump to return to the original frequency. Remote monitoring system for absorption chillers.
3. The control unit according to claim 1 or 2, wherein when the control unit restores the drive frequency of the dilute absorbent pump, the control unit does not perform the COP improvement control until the absorption chiller stops. Remote monitoring system for absorption chillers.
2. When the control for improving COP is performed, the control unit performs control so as to change the change amount of the drive frequency of the dilute absorbent pump based on the difference between the assumed concentration of the absorbent and the current concentration. 4. The remote monitoring system for an absorption chiller according to any one of claims 3 to 4.
connecting a cloud adapter capable of communicating with a cloud server to the absorption chiller;
The remote monitoring system for an absorption chiller according to any one of claims 1 to 4, wherein the control unit is a server control unit of the cloud server or an adapter control unit of the cloud adapter.