JP6789847B2 - Absorption chiller - Google Patents

Description

The present invention relates to an absorption chiller, and more particularly to an absorption chiller capable of detecting an increasing tendency of gas usage.

Generally, there is known an absorption chiller provided with a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, and connecting these with pipes to form circulation paths for an absorbent liquid and a refrigerant, respectively. The absorption chiller is used, for example, for central air conditioning in office buildings.
In such an absorption chiller, conventionally, for example, a single-effect operation of heating an absorption liquid using hot water supplied to an exhaust heat regenerator as a heat source and heating the absorption liquid using a gas burner provided in a high-temperature regenerator as a heat source. It is configured to enable single-effect operation, and is equipped with a mode changeover switch that switches the operation mode of each operation. When the operation mode is switched from single-double effect operation to single-effect operation by this mode changeover switch, The control device has a technology for stopping the gas burner and controlling the temperature of the absorption liquid in the high-temperature regenerator so as to shift to the single-effect operation when the temperature of the absorption liquid drops below a predetermined temperature at which the absorption liquid is sufficiently diluted. It is disclosed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-048958

Generally, in the conventional exhaust heat utilization absorption chiller, since the heat of exhaust hot water is used as a heat source, it is possible to control so as to reduce the amount of gas used.
However, in the conventional technique, it has not been determined whether the gas reduction amount is larger or smaller than the assumed reduction amount. Therefore, since it is not possible to detect an increasing tendency of the amount of gas used, it is not possible to take appropriate measures and maintain the COP above a certain level.

The present invention has been made in view of the above circumstances, and it is possible to detect an increasing tendency of the gas usage amount, and when the gas usage amount is increasing, a forecast is issued to prompt an appropriate response. It is an object of the present invention to provide an absorption chiller capable of holding COP above a certain level.

In order to achieve the above object, the present invention includes an exhaust heat regenerator, a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, and connects these with pipes to provide circulation paths for an absorbent liquid and a refrigerant, respectively. In the formed absorption chiller that utilizes exhaust heat, the amount of gas used that is detected regularly is acquired, and the average amount of gas used for one month is increased by more than a predetermined amount from the assumed amount of gas used. When it is determined, it is equipped with a control device that issues a forecast of maintenance instructions, and the control device is based on a pre-made assumed gas usage curve without exhaust heat, and is assumed gas without exhaust heat according to the cooling load. In addition to calculating the usage amount, the estimated gas usage amount with exhaust heat is calculated according to the cooling load based on the estimated gas usage amount curve with exhaust heat, and the estimated gas reduction rate is calculated based on these estimated gas usage amounts. In addition to the calculation, the measured gas reduction rate is calculated based on the measured gas usage amount, the ratio of the measured gas reduction rate to the assumed gas reduction rate is calculated, and when this ratio becomes 80% or less, maintenance is performed. The control device is characterized in that when the exhaust heat recovery amount is 80% or less of the rated exhaust heat recovery amount, a forecast is issued to prompt the confirmation of the cause of the decrease in the exhaust heat recovery amount. To do.

According to this, when the control device determines that the average gas usage has increased by more than a predetermined amount from the assumed gas usage, a forecast issuance of maintenance instructions is issued, and appropriate measures are taken by the forecast issuance. be able to. In addition, when the ratio of the measured gas reduction rate to the assumed gas reduction rate becomes low due to the control device, a forecast is issued. Therefore, by taking appropriate measures by forecasting, the COP is maintained above a certain level. can do. Furthermore, since the factors that increase the amount of gas used are presented, the maintenance worker can take appropriate measures by issuing the forecast.

According to the present invention, when the control device determines that the average gas usage has increased by a predetermined amount or more from the assumed gas usage, a forecast issuance of a maintenance instruction is issued. Therefore, appropriate measures are taken by the forecast issuance. By doing so, the COP can be maintained above a certain level.

The schematic block diagram of the absorption chiller which concerns on 1st Embodiment of this invention. The block diagram which shows the control structure of 1st Embodiment. The flowchart which shows the operation of 1st Embodiment. The graph which shows the relationship of the assumed gas use amount with respect to the cooling load of 2nd Embodiment. The flowchart which shows the operation of 2nd Embodiment.

The first invention includes a waste heat regenerator, a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, and these are connected by pipes to form a circulation path for an absorbent liquid and a refrigerant, respectively. In the heat utilization type absorption chiller, if the gas usage amount that is detected regularly is acquired and it is judged that the average gas usage amount for one month has increased by more than the specified amount from the assumed gas usage amount, maintenance It is characterized by being equipped with a control device for issuing a forecast of an instruction.
According to this, when the control device determines that the average gas usage has increased by more than a predetermined amount from the assumed gas usage, a forecast issuance of maintenance instructions is issued, and appropriate measures are taken by the forecast issuance. As a result, the COP can be maintained above a certain level.

The second invention is characterized in that the control device calculates a cooling load and calculates the assumed gas usage amount based on the calculated cooling load.
According to this, since the estimated gas usage amount according to the cooling load is calculated, it is possible to issue a forecast according to the cooling load.

In the third invention, the control device calculates the estimated gas usage without exhaust heat according to the cooling load based on the assumed gas usage curve without exhaust heat created in advance, and also has exhaust heat. Based on the assumed gas usage curve, calculate the estimated gas usage with exhaust heat according to the cooling load, calculate the estimated gas reduction rate based on these estimated gas usage, and based on the measured gas usage. The measured gas reduction rate is calculated, the ratio of the measured gas reduction rate to the assumed gas reduction rate is calculated, and when this ratio becomes 80% or less, a forecast is issued to instruct maintenance. It is characterized by doing.
According to this, when the ratio of the measured gas reduction rate to the assumed gas reduction rate becomes low by the control device, a forecast is issued. Therefore, by taking appropriate measures by the forecast issuance, the COP is set to a certain level. It can be held above.

A fourth aspect of the present invention is characterized in that the control device controls the forecast issuance when the cooling load is 40% or more.
According to this, when the cooling load is 40% or more, the forecast issuance is controlled, and when the cooling load is less than 40%, the forecast is not controlled. When the cooling load is less than 40%, the gas burner is controlled to be turned on and off, so an error occurs due to this control, and the increasing tendency of the gas consumption cannot be stably determined.

A fifth aspect of the invention is characterized in that, when the exhaust heat recovery amount is the rated exhaust heat recovery amount × 80% or less, the control device issues a notification prompting confirmation of a factor for reducing the exhaust heat recovery amount.
According to this, the factors that increase the amount of gas used are presented, so that the maintenance worker can take appropriate measures by issuing the forecast.

The sixth invention includes a vacuum degree detecting means for detecting that the vacuum degree is lowered, and when the control device determines that the vacuum degree is lowered by the vacuum degree detecting means, the vacuum degree is reduced. It is characterized by issuing a notification prompting confirmation.
According to this, the factors that increase the amount of gas used are presented, so that the maintenance worker can take appropriate measures by issuing the forecast.

A seventh aspect of the invention is characterized in that the control device issues an alarm prompting confirmation of an operating state of the device, except when it is determined that the amount of exhaust heat recovered and the degree of vacuum are lowered.
According to this, the factors that increase the amount of gas used are presented, so that the maintenance worker can take appropriate measures by issuing the forecast.

An eighth invention is characterized in that a remote monitoring system capable of communicating with the control device is provided, and a forecast is issued by the remote monitoring system based on information sent from the control device.
According to this, it is possible to notify the maintenance worker of the increase in gas consumption by issuing a forecast by the remote monitoring system.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the absorption chiller according to the first embodiment. The absorption chiller 100 uses water as a refrigerant and an aqueous solution of lithium bromide (LiBr) as an absorption liquid, and this absorption liquid is relatively generated by a heat source generator (for example, a solar water heater or a cogeneration device). It is an exhaust heat recovery type (so-called Genelink) absorption chiller-heater equipped with an exhaust heat regenerator that heats with hot water at a low temperature (for example, about 80 ° C.).

As shown in FIG. 1, the absorption chiller 100 includes an evaporator 1, an absorber 2 arranged in parallel with the evaporator 1, and an evaporator absorber body 3 containing 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 juxtaposed with the low-temperature regenerator 6, and these low-temperature regenerator 6 and the condenser 7 are housed. It includes a low temperature regenerator condenser body 8, an exhaust heat regenerator 9 that uses hot water supplied from other equipment as a heat source, and an exhaust heat regenerator body 11 that houses the exhaust heat regenerator 9.

In the present embodiment, the low temperature regenerator body 8 and the exhaust heat regenerator body 11 are integrally connected and formed, so that gas (steam) can communicate between the exhaust heat regenerator 9 and the low temperature regenerator 6. ing.
Further, the absorption chiller 100 includes a low temperature heat exchanger 12, a high temperature heat exchanger 13, a refrigerant drain heat recovery device 17, a rare absorbent pump 45, an intermediate absorbent pump 46, and a concentrated absorbent pump 47. And a refrigerant pump 48, and each of these devices is connected by pipes via absorption liquid tubes 21 to 25, refrigerant pipes 31 to 35, and the like to form a circulation path.

The evaporator 1 is provided with a chilled water pipe 14 for circulating and supplying a brine that has exchanged heat with a refrigerant in the evaporator 1 to a heat load (for example, an air conditioner) (not shown). A heat transfer tube 14A formed in a part thereof is arranged in the evaporator 1.
Further, on the upstream side of the heat transfer tube 14A of the chilled water pipe 14, a chilled water inlet temperature sensor 70 for measuring the temperature on the inlet side of the brine flowing in the chilled water pipe 14 is provided, and the heat transfer tube 14A of the chilled water pipe 14 is provided. A chilled water outlet temperature sensor 71 for measuring the temperature on the outlet side of the brine flowing through the chilled water pipe 14 is provided on the downstream side of the chilled water pipe 14. The chilled water pipe 14 is provided with a chilled water differential pressure sensor 72 that detects the pressure difference between the inlet side and the outlet side of the chilled water pipe 14.
The absorber 2 and the condenser 7 are provided with a cooling water pipe 15 for sequentially flowing the cooling water to the absorber 2 and the condenser 7, and each heat transfer tube 15A formed in a part of the cooling water pipe 15 is provided. , 15B are arranged in the absorber 2 and the condenser 7, respectively.

Further, in the exhaust heat regenerator 9, hot water at a relatively low temperature (for example, about 80 ° C.) generated by a heat source generator (for example, a solar water heater or a cogeneration apparatus) (not shown) is used in the exhaust heat regenerator 9. The exhaust hot water supply pipe 16 for circulating supply is provided in. The exhaust hot water supply pipe 16 adjusts the flow rate of the heat transfer pipe 16A arranged in the exhaust heat regenerator 9, the bypass pipe 16B connected in parallel to the heat transfer pipe 16A, and the hot water supplied to the heat transfer pipe 16A. It is equipped with a three-way valve 28 that can be switched for the purpose.
The exhaust hot water inlet temperature sensor 73 is provided on the exhaust hot water inlet side of the exhaust hot water supply pipe 16, and the exhaust hot water outlet temperature sensor 74 is provided on the exhaust hot water outlet side of the exhaust hot water supply pipe 16. There is. The exhaust hot water supply pipe 16 is provided with an exhaust hot water differential pressure sensor 75 that detects the pressure difference between the inlet side and the outlet side of the exhaust hot water supply pipe 16.

The absorber 2 has a function of absorbing the refrigerant vapor evaporated in the evaporator 1 into the absorbing liquid and keeping the pressure in the evaporator absorber body 3 in a high vacuum state. At the lower part of the absorber 2, a rare absorption liquid reservoir 2A for absorbing the refrigerant vapor and accumulating the diluted rare absorption liquid is formed, and the rare absorption liquid reservoir 2A has a rare absorption liquid pump 45. One end of the liquid pipe 21 is connected. The rare absorption liquid pipe 21 includes a branched rare absorption liquid pipe 21A that branches on the downstream side of the rare absorption liquid pump 45.
The branched rare absorption liquid pipe 21A rejoins the rare absorption liquid pipe 21 on the downstream side of the low temperature heat exchanger 12 of the rare absorption liquid pipe 21 after passing through the refrigerant drain heat recovery device 17. The other end of the rare absorption liquid pipe 21 is connected to a spreader 9A provided in the exhaust heat regenerator 9.

A heat transfer tube 16A formed in a part of the exhaust hot water supply pipe 16 is arranged in the exhaust heat regenerator 9, and the hot water is circulated through the exhaust hot water supply pipe 16 to be sprayed through the spreader 9A. The absorbed liquid can be regenerated by heating, that is, the refrigerant in the absorbed liquid can be evaporated to concentrate the absorbed liquid.
Further, an absorption liquid pool in which the absorption liquid sprayed through the sprayer 9A is collected is formed in the lower part of the exhaust heat regenerator 9, and the first intermediate absorption liquid pipe having the intermediate absorption liquid pump 46 is formed in this absorption liquid pool. One end of 22 is connected. The other end of the first intermediate absorption liquid tube 22 is opened to the air layer portion 5B located above the heat exchange portion 5A formed in the high temperature regenerator 5 after passing through the high temperature heat exchanger 13. ..
Further, the first intermediate absorption liquid pipe 22 is branched into the first branch pipe 22A and the second branch pipe 22B on the downstream side of the intermediate absorption liquid pump 46, and the first branch pipe 22A does not pass through the high temperature heat exchanger 13. Then, after passing through the exhaust gas heat exchanger 41 provided in the exhaust path 40, the air layer portion 5B in the high temperature regenerator 5 is opened. The second branch pipe 22B is open in the low temperature regenerator 6.

The high temperature regenerator 5 is configured by accommodating the gas burner 4 in the shell 60, and a heat exchange unit 5A for heating and regenerating the absorbed liquid using the flame of the gas burner 4 as a heat source is formed above the gas burner 4. An exhaust path 40 through which the 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. Further, a gas pipe 61 to which fuel gas is supplied and an intake pipe 63 to which air from a blower 62 is supplied are connected to the gas burner 4, and fuel gas and air are connected to the gas pipe 61 and the intake pipe 63. A control valve 64 for controlling the amount of gas is provided.
Further, the gas pipe 61 is provided with a gas flow meter 65 for detecting the flow rate of the fuel gas.

On the side of the heat exchange unit 5A, an intermediate absorption liquid reservoir 5C is formed in which the intermediate absorption liquid that has flowed out from the heat exchange unit 5A after being heat-regenerated by the heat exchange unit 5A is collected. One end of the second intermediate absorption liquid pipe 23 is connected to the lower end of the intermediate absorption liquid reservoir 5C, and the second intermediate absorption liquid pipe 23 is provided with a high temperature heat exchanger 13. The high-temperature heat exchanger 13 heats the absorption liquid flowing through the first intermediate absorption liquid pipe 22 by the heat of the high-temperature intermediate absorption liquid flowing out from the intermediate absorption liquid reservoir 5C, and the gas burner 4 in the high-temperature regenerator 5 We are trying to reduce fuel consumption.
The other end of the second intermediate absorption liquid pipe 23 is connected to the concentrated absorption liquid pipe 25 connecting the low temperature regenerator 6 and the absorber 2. Further, the upstream side of the high temperature heat exchanger 13 of the second intermediate absorption liquid pipe 23 and the absorber 2 are connected by an absorption liquid pipe 24 in which an on-off valve V1 is interposed.

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 absorption liquid accumulated in the absorption liquid reservoir 6A formed in the low-temperature regenerator 6, and regenerates the absorption liquid in the absorption liquid reservoir 6A. A heat transfer tube 31A formed in a part of a 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 in the above. By flowing the refrigerant vapor through the refrigerant pipe 31, the heat of the refrigerant vapor is transmitted to the absorption liquid accumulated in the absorption liquid reservoir 6A through the heat transfer pipe 31A, and the absorption liquid is further concentrated.
One end of the concentrated absorption liquid pipe 25 is connected to the absorption liquid reservoir 6A of the low temperature regenerator 6, and the other end of the concentrated absorption liquid pipe 25 is a concentrated liquid sprayer provided in the upper part of the air layer portion 2B of the absorber 2. It is connected to 2C. The concentrated absorption liquid pipe 25 is provided with a concentrated absorption liquid pump 47 and a low temperature heat exchanger 12. The low-temperature heat exchanger 12 heats the rare absorption liquid flowing through the second rare absorption liquid tube 21C by the heat of the concentrated absorption liquid flowing out from the absorption liquid reservoir 6B of the low-temperature regenerator 6.

Further, the upstream side of the concentrated absorption liquid pump 47 of the concentrated absorption liquid pipe 25 and the upstream side of the intermediate absorption liquid pump 46 of the first intermediate absorption liquid pipe 22 are connected by a first bypass pipe 26 that bypasses the high temperature regenerator 5. The concentrated absorption liquid pipe 25 is provided with a second bypass pipe 27 that bypasses the concentrated absorption liquid pump 47 and the low temperature heat exchanger 12.
When the operation of the intermediate absorption liquid pump 46 is stopped, the absorption liquid flowing out from the absorption liquid pool of the exhaust heat regenerator 9 is the first intermediate absorption liquid pipe 22, the first bypass pipe 26, and the concentrated absorption liquid pump. 47, It is supplied into the absorber 2 through the low temperature heat exchanger 12 and the concentrated absorption liquid tube 25. Further, when the operation of the concentrated absorption liquid pump 47 is stopped, the absorption liquid flowing out from the absorption liquid pool of the exhaust heat regenerator 9 is the first intermediate absorption liquid pipe 22, the first bypass pipe 26, and the second bypass pipe. It is supplied into the absorber 2 through 27 and the concentrated absorption liquid tube 25.

As described above, the air 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 and a refrigerant drain heat recovery device 17 piped to the absorption liquid reservoir 6A of the low temperature regenerator 6, and is located upstream of the heat transfer pipe 31A of the refrigerant pipe 31 and the air layer portion of the absorber 2. It is connected to 2B by a refrigerant pipe 32 in which an on-off valve V2 is interposed.
Further, one end of a refrigerant pipe 34 through which the refrigerant flowing out of the refrigerant liquid pool 7A flows is connected to the refrigerant liquid reservoir 7A of the condenser 7, and the other end of the refrigerant pipe 34 is a downwardly curved U-seal portion 34A. It is connected to the air layer portion 1A of the evaporator 1 via.
A refrigerant liquid reservoir 1B in which the liquefied refrigerant is stored is formed below the evaporator 1, and a refrigerant pump 48 is interposed between the refrigerant liquid reservoir 1B and the spreader 1C arranged above the air layer portion 1A of the evaporator 1. It is connected by a refrigerant pipe 35.

Next, the control configuration of this embodiment will be described.
FIG. 2 is a block diagram showing a control configuration of the present embodiment.
As shown in FIG. 2, the absorption chiller 100 of the present embodiment includes a controller 50, and the controller 50 includes a control device 51. The control device 51 centrally controls each part of the absorption chiller 100, and is a CPU as an arithmetic execution unit, a ROM that non-volatilely stores a basic control program that can be executed by the CPU, predetermined data, and the like. , RAM, and other peripheral circuits.
Further, the control device 51 includes a chilled water inlet temperature sensor 70, a chilled water outlet temperature sensor 71, a chilled water differential pressure sensor 72, a hot water inlet temperature sensor 73, and a hot water outlet temperature sensor 74, which includes a hot water differential pressure sensor 75 and a gas flow rate. A total of 65 detection signals are configured to be input respectively.
Further, the controller 50 includes a memory 52, a timer 53, an operation unit 54, and an operation display unit 55, respectively.

The controller 51 of the controller 50 controls the fuel control valve 64 of the gas burner 4 of the absorption chiller 100 to control the combustion by the gas burner 4, and also controls the rare absorption liquid pump 45, the intermediate absorption liquid pump 46, and the concentrated absorption. It is configured to control the drive of the liquid pump 47 and the refrigerant pump 48. Further, the control device 51 of the controller 50 controls the rare absorption liquid pump 45, the intermediate absorption liquid pump 46, the concentrated absorption liquid pump 47, and the refrigerant pump 48 by controlling the rare absorption liquid pump 45, the intermediate absorption liquid pump 46, and the intermediate absorption liquid pump 46. , The flow rate is controlled by the concentrated absorption liquid pump 47 and the refrigerant pump 48. Further, the control device 51 is configured to control the opening and closing of each of the valves 28, V1 and V2.

Further, the controller 50 is configured to be able to communicate with the remote monitoring system 80 via, for example, a wireless or wired communication means, and is configured to transmit the information acquired by the controller 50 to the remote monitoring system 80. There is.

In the present embodiment, the control device 51 detects the inlet temperature of the exhaust hot water by the exhaust hot water inlet temperature sensor when the cooling operation is started, and when the exhaust hot water inlet temperature is 70 ° C. or higher, the control device 51 , Judge that there is exhaust heat.
When it is determined that there is exhaust heat, the control device 51 detects the amount of gas used by the current gas burner 4 and calculates the cooling load. The amount of gas used is detected by the gas flow meter 65.
The cooling load is calculated based on the following formula.
Cooling load = (Cold water inlet / outlet temperature difference ÷ Rated chilled water inlet / outlet temperature difference) × (Cold water differential pressure value ÷ Rated chilled water differential pressure value) 0.5 × 100 (%)
That is, the difference between the inlet side temperature and the outlet side temperature of the chilled water is calculated by the chilled water inlet temperature sensor 70 and the chilled water outlet temperature sensor 71. Next, since the cold water differential pressure value and the cold water flow rate have a certain relationship, the cold water flow rate can be obtained by calculating the 0.5th power of the cold water differential pressure value with respect to the rated cold water differential pressure value. ..

Next, the control device 51 determines whether or not the cooling load is 40% or more, and if the cooling load is 40% or more, calculates the assumed gas usage amount. If the cooling load is less than 40%, the control of this embodiment is not performed.
Here, the reason why the control is performed only when the cooling load is 40% or more is that when the cooling load is less than 40%, the control for dealing with the cooling load is performed by the gas burner 4 as a system setting. This is because the combustion is controlled to be ON and OFF, so that an error in the determination value described later may occur. Therefore, it is not always necessary to judge whether or not the cooling load is 40% or more, and the setting may be made according to the cooling load that can be switched to ON / OFF control of combustion by the gas burner 4.

Next, the control device 51 calculates the assumed gas usage amount.
The estimated gas usage is calculated based on the following formula.
Estimated gas usage = (A x cooling load) -B
Here, A and B are constants for each system specification.

After calculating the assumed gas usage amount, the control device 51 obtains a determination value of the gas usage amount. The judgment value is calculated by the following formula.
Judgment value = (gas usage ÷ estimated gas usage) -1
The calculation of the determination value is performed, for example, once a day at a predetermined time, and the control device 51 obtains the average value of the calculated determination values.
The control device 51 determines whether or not the average determination value is equal to or greater than a predetermined value once a month, for example, at the end of the month.

In the present embodiment, when the determination value is 0.1 or more, that is, when the gas usage amount is 10% or more, the control device 51 is configured to determine that the gas usage amount is increasing. Has been done.
When the control device 51 determines that the determination value is 0.1 or more, the control device 51 controls to issue a forecast issuing instructing maintenance. The forecast issuance of the maintenance instruction is performed, for example, by displaying the maintenance instruction on the operation display unit 55.
When the control device 51 determines that the determination value is 0.1 or more, the controller 50 transmits the information to the remote monitoring system 80, and the remote monitoring system 80 issues a forecast of maintenance instructions. You may.

A factor that is considered to be an increase in the amount of gas used is, for example, a decrease in the amount of exhaust heat recovered.
Therefore, when the exhaust heat recovery amount ≤ the rated exhaust heat recovery amount × 80 (%), the control device 51 determines that the exhaust heat recovery amount is decreasing, and the factor that the exhaust heat recovery amount is decreasing. Give maintenance instructions to prompt confirmation of.

As another factor, for example, the inside of the absorption chiller 100 is normally operated at a pressure below the atmosphere, but the internal pressure of the absorption chiller 100 becomes high and the degree of vacuum decreases. If so, gas consumption is expected to increase. When determining whether or not the degree of vacuum is reduced, for example, although not shown, an air bleeding device is attached to the absorber 2, and when the internal pressure of the absorption chiller 100 becomes high, the bleeding device The bleed pressure inside increases. Therefore, when it is determined by the vacuum degree detecting means that the bleeding pressure of the bleeding device has increased, it can be determined that the degree of vacuum has decreased.
In this case, when the control device 51 determines that the degree of vacuum inside the absorption chiller 100 has decreased, the control device 51 gives a maintenance instruction to prompt confirmation of the cause of the decrease in the degree of vacuum.
When the absorption chiller 100 is controlled to issue a forecast of a decrease in the degree of vacuum, the forecast is issued due to an increase in the amount of gas used and the forecast of the decrease in the degree of vacuum is issued at the same time. If it is reported, a forecast may be issued to prompt confirmation of a decrease in the degree of vacuum.

Further, when the decrease in the exhaust heat recovery amount and the decrease in the degree of vacuum are not confirmed, the control device 51 gives a maintenance instruction to prompt the confirmation of the operating state of each device in the absorption chiller 100.

When the forecast issuance of the maintenance instruction is issued, the maintenance worker of the absorption chiller 100 carries out the maintenance of the absorption chiller 100 in accordance with the maintenance instruction.
When the amount of gas used becomes less than the assumed amount of gas used due to the implementation of this maintenance, the control device 51 determines that the amount of gas used has decreased, and notifies the remote monitoring system 80 of the maintenance measures and results. It is transmitted, and the remote monitoring system 80 informs the user of the action content and result as a remote monitoring report.
In the above embodiment, when the amount of gas used is 10% or more, it is determined that the amount of gas used is increasing. Therefore, when the amount of gas used is less than 10%. , The amount of gas used may be judged to be appropriate.

Next, the operation of this embodiment will be described.
During the cooling operation, brine (for example, cold water) is circulated and supplied to a heat load (not shown) through the cold water pipe 14. The control device 51 puts heat into the absorption chiller 100 so that the outlet side temperature of the brine evaporator 1 (the temperature detected by the chilled water outlet temperature sensor 71) becomes a predetermined set temperature, for example, 7 ° C. Is controlled.
Specifically, in the control device 51, for example, the heat load is large, and the temperature of the hot water supplied to the exhaust heat regenerator 9 via the exhaust hot water supply pipe 16 reaches a predetermined temperature (for example, 85 ° C.). At that time, the rated amount of hot water is supplied from the exhaust hot water supply pipe 16 to the exhaust heat regenerator 9, all the pumps 45 to 48 are started, and the gas is burned in the gas burner 4, and the chilled water outlet temperature sensor 71 measures. The thermal power of the gas burner 4 is controlled so that the temperature of the brine is 7 ° C.

In this case, the rare absorbent liquid conveyed from the absorber 2 to the exhaust heat regenerator 9 by the rare absorbent liquid pump 45 via the rare absorbent liquid pipe 21 is the exhaust hot water in the absorbent liquid pool in the exhaust heat regenerator 9. The refrigerant in the rare absorption liquid is evaporated and separated by being heated by the hot water supplied from the supply pipe 16 through the pipe wall of the heat transfer pipe 16A.

A part of the intermediate absorption liquid whose absorption liquid concentration has increased by evaporating and separating the refrigerant is passed through the high temperature heat exchanger 13 or the exhaust gas heat exchanger 41 by the intermediate absorption liquid pump 46 of the first intermediate absorption liquid pipe 22. It is heated and sent to the high temperature regenerator 5. The rest of the intermediate absorption liquid is sent to the low temperature regenerator 6 through the second branch pipe 22B.
Since the intermediate absorption liquid sent to the high temperature regenerator 5 is heated by the flame by the gas burner 4 and the high temperature combustion gas in the high temperature regenerator 5, the refrigerant in the intermediate absorption liquid evaporates and separates. The intermediate absorption liquid whose concentration has increased by evaporating and separating the refrigerant in the high temperature regenerator 5 is sent to the concentrated absorption liquid pipe 25 via the high temperature heat exchanger 13 and merges with the absorption liquid via the low temperature regenerator 6. ..

On the other hand, the intermediate absorbent liquid sent to the low temperature regenerator 6 is heated by the high temperature refrigerant vapor supplied from the high temperature regenerator 5 via the refrigerant pipe 31 and flowing into the heat transfer tube 31A, and the refrigerant is further separated and concentrated. Is further increased, and this concentrated absorption liquid merges with the above-mentioned absorption liquid 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 absorption liquid pump 47, and the concentrated liquid spreader. It is sprayed from 2C.

The refrigerant separated and generated by the low temperature regenerator 6 enters the condenser 7, condenses, and accumulates in the refrigerant liquid reservoir 7A. Then, when a large amount of refrigerant liquid is accumulated in the refrigerant liquid pool 7A, this refrigerant liquid flows out from the refrigerant liquid pool 7A, enters the evaporator 1 via the refrigerant pipe 34, is pumped by the operation of the refrigerant pump 48, and is sprayed. It is sprayed from the vessel 1C onto the heat transfer tube 14A of the cold water tube 14.
The refrigerant liquid sprayed on the heat transfer tube 14A removes heat of vaporization from the brine passing through the inside of the heat transfer tube 14A and evaporates. Therefore, the brine passing through the inside of the heat transfer tube 14A is cooled, and thus the brine having a lowered temperature is released. The heat load is supplied from the chilled water pipe 14, and a cooling operation such as cooling is performed.
Then, the refrigerant evaporated in the evaporator 1 enters the absorber 2, is absorbed by the concentrated absorption liquid supplied from the low temperature regenerator 6 and sprayed from above, and accumulates in the rare absorption liquid reservoir 2A of the absorber 2, which is rare. The circulation carried to the exhaust heat regenerator 9 by the absorbent pump 45 is repeated.

At this time, the amount of heating by the gas burner 4, specifically, the amount of fuel gas supplied to the gas burner 4 is controlled by the control device 51 so that the temperature measured by the chilled water outlet temperature sensor 71 becomes a predetermined 7 ° C.

Further, in the operation in which the gas burner 4 does not burn, the absorbing liquid is heated in the exhaust heat regenerator 9 by the hot water supplied from the exhaust hot water supply pipe 16 to evaporate and separate the refrigerant. Then, the absorption liquid having a high absorption liquid concentration is returned to the absorber 2 via the first bypass pipe 26, the concentrated absorption liquid pump 47, and the low temperature heat exchanger 12.
On the other hand, the refrigerant vapor separated and generated by the exhaust heat regenerator 9 enters the refrigerant liquid reservoir 7A of the condenser 7 via the low temperature regenerator 6 and flows into the evaporator 1 via the refrigerant pipe 34.
The refrigerant liquid flowing into the evaporator 1 is sprayed from the spreader 1C onto the heat transfer tube 14A of the chilled water pipe 14 by the operation of the refrigerant pump 48, and takes heat from the brine passing through the heat transfer tube 14A to evaporate and absorb it. Circulation is performed in which the container 2 is absorbed by the absorbing liquid sprayed from above. The heat generated when the absorbing liquid absorbs the refrigerant is cooled by the heat transfer tube 15A of the cooling water pipe 15 arranged in the absorber 2.

At this time, the amount of heating in the exhaust heat regenerator 9, specifically, the amount of hot water taken into the heat transfer tube 16A from the exhaust hot water supply pipe 16 so that the temperature measured by the chilled water outlet temperature sensor 71 becomes a predetermined 7 ° C. That is, the opening degree of the three-way valve 28 is controlled by the control device 51.

Next, the control operation according to the present embodiment will be described with reference to the flowchart shown in FIG.
In the present embodiment, when the cooling operation is started (ST1), the control device 51 detects the inlet temperature of the exhaust hot water by the exhaust hot water inlet temperature sensor, and whether or not the exhaust hot water inlet temperature is 70 ° C. or higher. (ST2). When the exhaust hot water inlet temperature is 70 ° C. or higher (ST2: YES), the control device 51 determines that there is exhaust heat.
When it is determined that there is exhaust heat, the control device 51 determines whether or not the predetermined time of the day (in this case, the predetermined time is shown as an example of 13:00) has been reached (ST3). ), When the predetermined time is reached (ST3: YES), the control device 51 detects the amount of gas used by the current gas burner 4 and calculates the cooling load (ST4).

Next, the control device 51 determines whether or not the cooling load is 40% or more (ST5), and if the cooling load is 40% or more (ST5: YES), calculates the assumed gas usage amount (ST6). ).
After calculating the assumed gas usage amount, the control device 51 obtains a determination value of the gas usage amount (ST7) and obtains an average value of the calculated determination values (ST8).
At the end of the month (ST9: YES), the control device 51 determines whether or not the average determination value is 0.1 or more (ST10).
Then, when the determination value is 0.1 or more (ST10: YES), the control device 51 determines that the amount of gas used is increasing, and issues a forecast issuing an instruction for maintenance (ST11).

When the forecast issuance of the maintenance instruction is issued, the maintenance worker of the absorption chiller 100 carries out the maintenance of the absorption chiller 100 according to the maintenance instruction (ST12).
After performing this maintenance (ST12: YES), the control device 51 determines whether or not the gas usage amount is equal to or less than the assumed gas usage amount (ST13). When the gas usage is less than the expected gas usage (ST13: YES), the control device 51 determines that the gas usage has decreased and transmits the maintenance procedure details and results to the remote monitoring system 80. Then, the remote monitoring system 80 informs the user of the action content and the result as a remote monitoring report (ST14).

As described above, in the present embodiment, when the gas usage amount detected periodically is acquired and it is determined that the average gas usage amount for one month is increased by a predetermined value or more from the assumed gas usage amount. The control device 51 for issuing a forecast of maintenance instructions is provided.
According to this, when the control device 51 determines that the average gas usage amount has increased by a predetermined amount or more from the assumed gas usage amount, a forecast issuance of a maintenance instruction is issued. Therefore, an appropriate response is taken by the forecast issuance. By doing so, the COP can be maintained above a certain level.

Further, in the present embodiment, the control device 51 calculates the cooling load, and calculates the assumed gas usage amount based on the calculated cooling load.
According to this, since the estimated gas usage amount according to the cooling load is calculated, it is possible to issue a forecast according to the cooling load.

Further, in the present embodiment, the control device 51 controls the forecast issuance when the cooling load is 40% or more.
According to this, since the forecast issuance is controlled when the cooling load is 40% or more, there is no error due to the control when the cooling load is less than 40%, and the gas consumption tends to increase. You can make a stable judgment.

Further, in the present embodiment, when the exhaust heat recovery amount is the rated exhaust heat recovery amount × 80% or less, the control device 51 issues a report prompting confirmation of the factor for reducing the exhaust heat recovery amount.
According to this, the factors that increase the amount of gas used are presented, so that the maintenance worker can take appropriate measures by issuing the forecast.

Further, in the present embodiment, the vacuum degree detecting means for detecting that the vacuum degree is lowered is provided, and when the control device 51 determines that the vacuum degree is lowered by the vacuum degree detecting means, the vacuum degree is reduced. Is issued to prompt confirmation of.
According to this, the factors that increase the amount of gas used are presented, so that the maintenance worker can take appropriate measures by issuing the forecast.

Further, in the present embodiment, the control device 51 issues a warning prompting confirmation of the operating state of the device except when it is determined that the amount of exhaust heat recovered and the degree of vacuum are lowered.
According to this, the factors that increase the amount of gas used are presented, so that the maintenance worker can take appropriate measures by issuing the forecast.

Further, in the present embodiment, the remote monitoring system 80 capable of communicating with the control device 51 is provided, and the remote monitoring system 80 issues a forecast based on the information sent from the control device 51.
According to this, the maintenance worker can be notified of the increase in the amount of gas used by issuing a forecast by the remote monitoring system 80.

Next, the second embodiment of the present invention will be described.
Since the configuration and control configuration of the absorption chiller 100 in the second embodiment are the same as those in the first embodiment, they will be described with reference to FIGS. 1 and 2 in the description of the second embodiment. ..
In the present embodiment, the control device 51 calculates the assumed gas usage amount with respect to the cooling load as in the first embodiment.
This estimated gas usage is calculated by calculating the estimated gas usage when there is exhaust heat and the estimated gas usage when there is no exhaust heat, and is based on the estimated gas usage when there is exhaust heat. Create an estimated gas usage curve and an estimated gas usage curve based on the estimated gas usage when there is no exhaust heat in advance.

FIG. 4 is a graph showing the relationship between the assumed gas usage amount and the cooling load. In FIG. 4, the solid line shows the assumed gas usage curve when there is exhaust heat, and the broken line shows the assumed gas usage curve when there is no exhaust heat.
The assumed gas usage curve created in this way is stored in the memory 52.

Then, in the present embodiment, the control device 51 calculates the estimated gas usage amount A from the assumed gas usage amount curve without exhaust heat based on the cooling load. Further, the control device 51 calculates the estimated gas usage amount B from the assumed gas usage amount curve with exhaust heat based on the cooling load.
After that, the control device 51 calculates the assumed gas reduction rate C based on the following formula.
C = (AB) ÷ A × 100 (%)
Further, the control device 51 detects the actually measured gas usage amount D, and calculates the actually measured gas reduction rate E based on the following formula.
E = (AD) ÷ A × 100 (%)

After performing the above calculation, the control device 51 calculates the ratio of the measured gas reduction rate E to the assumed gas reduction rate C based on the following formula, and when this ratio becomes 80% or less, maintenance is performed. It is configured to control to issue a forecast to instruct.
(E ÷ C) × 100 (%) ≦ 80 (%)
In this embodiment, the forecast is issued when the ratio of the measured gas reduction rate E to the assumed gas reduction rate C is 80% or less, but this ratio is the absorption chiller 100. It can be changed as appropriate according to the system.

Next, with reference to FIG. 4, a case where the cooling load is 70% will be specifically described as an example.
According to the assumed gas usage curve when there is no exhaust heat, the estimated gas usage A when the cooling load is 70% is 530 kW. According to the assumed gas usage curve when there is exhaust heat, the estimated gas usage B when the cooling load is 70% is 400 kW.
As a result, the assumed gas reduction rate C becomes as follows.
C = (530-400) ÷ 530 × 100 = 24.5%

Further, when the actually measured gas consumption D is 350 kW, the actually measured gas reduction rate E is as follows.
E = (530-350) ÷ 530 × 100 = 34.0%
In this case, the ratio of the measured gas reduction rate E to the assumed gas reduction rate C is as follows.
(E ÷ C) × 100 = (34.0 ÷ 24.5) × 100 = 138%
Therefore, since this ratio is larger than 80%, the forecast is not issued.

Next, the control operation according to the present embodiment will be described with reference to the flowchart shown in FIG.
In the present embodiment, when the cooling operation is started (ST21), the control device 51 is an example of a predetermined time in a day (in this case, a predetermined time of 13:00) as in the first embodiment. (ST22), and when the predetermined time is reached (ST22: YES), the control device 51 detects the amount of gas used by the current gas burner 4 and cools the air. Calculate the load (ST23).

Then, the control device 51 calculates the estimated gas usage amount A from the assumed gas usage amount curve without exhaust heat based on the cooling load (ST24). Further, the control device 51 calculates the estimated gas usage amount B from the assumed gas usage amount curve with exhaust heat based on the cooling load (ST25).
After that, the control device 51 calculates the assumed gas reduction rate C (ST26).
Further, the control device 51 calculates the actually measured gas reduction rate E based on the actually measured gas usage amount D (ST27).

After performing the above calculation, the control device 51 calculates the ratio of the measured gas reduction rate E to the assumed gas reduction rate C (ST28), and determines whether or not this ratio is 80% or less (ST29). ..
Then, when it is determined that the ratio of the measured gas reduction rate E to the assumed gas reduction rate C is 80% or less (ST29: YES), it is controlled to issue a forecast issuing an instruction for maintenance (ST30).

In this embodiment as well, as in the first embodiment, the control device 51 determines whether or not the cooling load is 40% or more, and the assumed gas is used only when the cooling load is 40% or more. The amount may be calculated.
Further, when the forecast issuance of the maintenance instruction is issued, the maintenance worker of the absorption chiller 100 performs the maintenance of the absorption chiller 100 in accordance with the maintenance instruction, and then the control device 51 uses gas. Judges whether or not the gas usage is less than the expected gas usage, and when it is judged that the gas usage has decreased, the maintenance measures and results are transmitted to the remote monitoring system 80, and the remote monitoring system 80 is used for remote control. The action content and result may be notified to the user as a monitoring report.

As described above, in the present embodiment, the control device 51 calculates the estimated gas usage without exhaust heat according to the cooling load based on the assumed gas usage curve without exhaust heat created in advance. At the same time, based on the assumed gas usage curve with exhaust heat, the estimated gas usage with exhaust heat is calculated according to the cooling load, the estimated gas reduction rate is calculated based on these estimated gas usage, and the actual measurement is performed. Calculate the measured gas reduction rate based on the amount of gas used in the above, calculate the ratio of the measured gas reduction rate to the assumed gas reduction rate, and when this ratio becomes 80% or less, issue a forecast to instruct maintenance. Control to do.
According to this, when the ratio of the measured gas reduction rate to the assumed gas reduction rate becomes low by the control device 51, the forecast is issued. Therefore, the COP is kept constant by taking appropriate measures by the forecast issuance. Can be held above the standard.

It should be noted that the present embodiment shows one aspect to which the present invention is applied, and the present invention is not limited to the above-described embodiment.
For example, in the above-described embodiment, the case where the exhaust heat of hot water (warm drainage) is applied to an absorption chiller using exhaust heat as a heat source has been described, but the present invention is not limited to this, and exhaust of steam. It can also be applied to an absorption chiller that uses heat as a heat source and uses exhaust heat.

As described above, the absorption chiller according to the present invention is suitable for the absorption chiller utilizing exhaust heat, and the COP should be maintained at a certain level or higher by taking appropriate measures by issuing a forecast. Can be used for the required applications.

1 Evaporator 2 Absorber 4 Gas burner 5 High temperature regenerator 6 Low temperature regenerator 7 Condenser 9 Exhaust heat regenerator 12 Low temperature heat exchanger 13 High temperature heat exchanger 14 Cold water pipe 15 Cooling water pipe 16 Exhaust hot water supply pipe 21 Rare absorption liquid pipe 45 Rare absorption liquid pump 46 Intermediate absorption liquid pump 47 Concentrated absorption liquid pump 48 Refrigerant pump 50 Controller 51 Controller 52 Memory 53 Timer 65 Gas flow meter 70 Cold water inlet temperature sensor 71 Cold water outlet temperature sensor 72 Cold water differential pressure sensor 73 Exhaust water inlet Temperature sensor 74 Exhaust hot water outlet temperature sensor 75 Exhaust hot water differential pressure sensor 80 Remote monitoring system 100 Absorption chiller

Claims (6)

It is equipped with an exhaust heat regenerator, a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, and these are connected by piping to form circulation paths for the absorbent liquid and the refrigerant, respectively. In the refrigerator
A control device that acquires the gas usage that is detected on a regular basis and issues a forecast of maintenance instructions when it is determined that the average gas usage for one month has increased by more than a predetermined amount from the assumed gas usage. Prepare,
The control device calculates the estimated gas usage without exhaust heat according to the cooling load based on the assumed gas usage curve without exhaust heat created in advance, and also makes the estimated gas usage curve with exhaust heat. Based on this, calculate the estimated gas usage with exhaust heat according to the cooling load.
The estimated gas reduction rate is calculated based on these assumed gas usage amounts, and the measured gas reduction rate is calculated based on the actually measured gas usage amount.
The ratio of the measured gas reduction rate to the assumed gas reduction rate is calculated, and when this ratio becomes 80% or less, a forecast is issued to instruct maintenance.
The control device is an absorption chiller characterized in that when the exhaust heat recovery amount is 80% or less of the rated exhaust heat recovery amount, an alarm prompting confirmation of a factor for reducing the exhaust heat recovery amount is issued . The absorption chiller according to claim 1, wherein the control device calculates a cooling load and calculates the assumed gas usage amount based on the calculated cooling load. The absorption chiller according to claim 1 or 2, wherein the control device controls forecast issuing when the cooling load is 40% or more . Equipped with a vacuum degree detecting means for detecting that the degree of vacuum is decreasing,
Any one of claims 1 to 3, wherein the control device issues an alarm prompting confirmation of the degree of vacuum when it is determined by the means for detecting the degree of vacuum that the degree of vacuum has decreased. The absorption chiller described in the section. Claims 1 to 4 are characterized in that the control device issues a warning prompting confirmation of the operating state of the device, except when it is determined that the amount of exhaust heat recovered and the degree of vacuum are lowered. The absorption chiller according to any one of the above. Equipped with a remote monitoring system capable of communicating with the control device
The absorption chiller according to any one of claims 1 to 5 , wherein a forecast is issued by the remote monitoring system based on the information sent from the control device .

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