JP4348449B2 - Absorption chiller / heater and its operation method - Google Patents

Description

  The present invention relates to an absorption chiller / heater and an operation method thereof. More specifically, the present invention relates to an absorption chiller / heater that can automatically clean a heat transfer tube and an operation method thereof. In the present specification, the absorption chiller / heater includes an absorption chiller.

  In the absorption chiller / heater, each part of the absorber, the condenser, the evaporator, and the regenerator is configured as a tubular heat exchanger that performs heat exchange via a tube wall. In general, the heat transfer efficiency of a pipe heat exchanger decreases when dirt is deposited on the pipe wall. However, the absorber and the condenser are scales because the cooling water circulation system is an open-air cycle using a cooling tower. There is a problem that the heat transfer efficiency is likely to be reduced because the portion is concentrated by heat radiation in the cooling tower, deposited in the tube, and adhered to the inner surface of the tube. For this reason, it is necessary to periodically clean the tube, and this is being implemented.

  In the washing and removing operation for the scale, it is necessary to dissolve and wash the scale using a chemical solution, which may cause environmental pollution due to washing.

  Therefore, a ball circulation cleaning method is generally performed in which a sponge ball is caused to flow through the cooling water circulation system, thereby cleaning the inner surface of the pipe (see Patent Documents 1 and 2, etc.). In the ball circulation cleaning method, for example, about several times a day, dozens of cleaning sponge balls having a size corresponding to the pipe diameter are supplied to the cooling water circulation system by the ball supply mechanism, and the sponge balls are supplied for a predetermined time. After the inside of the tube is circulated and cleaned, the ball is recovered by a ball recovery mechanism.

  However, in the ball circulation cleaning method, since the cleaning is usually performed while the sponge ball having a size slightly larger than the inner diameter of the heat transfer tube is pumped by cooling water, the operation state of the absorption chiller / heater is taken into consideration. If cleaning is started carelessly, the pressure balance and heat balance in the absorption chiller / heater system may be disrupted, resulting in abnormal operation.

  In order to avoid such abnormal operation, the ball circulation cleaning device is conventionally handled as a kind of equipment, and the operation of the ball circulation cleaning device is generally performed before or after the operation of the absorption chiller / heater. It is said that. In addition, in the case of an absorption chiller / heater that cannot be shut down, the passive operation of forcibly operating the absorption chiller / heater at a low load in response to a cleaning operation signal from the ball circulation cleaning device. Has been made. That is, there is a problem that there is a great restriction on cleaning by the ball circulation type cleaning device.

Therefore, the advent of the absorption chiller / heater that can be cleaned by the ball circulation cleaning device regardless of the operating condition and load of the absorption chiller / heater is eagerly desired by the parties concerned.
Japanese Patent Laid-Open No. 5-280899 Japanese Patent Laid-Open No. 5-126491

  The present invention has been made in view of the problems of the prior art, and an absorption chiller / heater that can be cleaned by a ball circulation cleaning device regardless of the operation status and load of the absorption chiller / heater and its operation It aims to provide a method.

The absorption chiller / heater of the present invention is an absorption chiller / heater comprising a cleaning device and a combustion device,
The absorption chiller / heater control device includes a cleaning schedule management unit, an operation state monitoring unit having a state index calculation unit, and a cleaning continuation determination unit.
The state index calculating means calculates a relative index obtained by dividing a state index represented by a ratio between a combustion amount during operation and a cooling water heat release amount by a maximum value of the state index,
The cleaning continuation determination unit has a cleaning continuation determination threshold ,
The cleaning continuation determination unit, to the relative index na determines cleaning continuation determination during operation by the threshold processing by the washing continuation determination threshold,
If the determination of the cleaning not is made in the determination, the control device, and wherein also be output from the combustion amount reduction command for commanding a reduction in combustion quantity of the combustion device.

In the absorption chiller / heater of the present invention, it is preferable that the threshold value for determining whether or not to continue washing can be changed based on a load condition or a seasonal factor of the absorption chiller / heater.

The operation method of the absorption chiller / heater of the present invention is the operation method of any one of the absorption chiller / heaters,
The procedure for setting the cleaning schedule;
Procedures for monitoring the operating conditions of the absorption chiller / heater,
Start the cleaning device and start cleaning,
A procedure for calculating a relative index;
A procedure for determining whether or not cleaning can be continued during operation by performing threshold processing on the relative index according to a threshold for determining whether or not cleaning can be continued;
A step of reducing the amount of combustion of the combustion device when the determination that the continuation of cleaning is impossible is made in the determination.

  According to the present invention, regardless of the operating conditions of the absorption chiller / heater, cleaning by the cleaning device can be performed, and whether or not the continuation can be continued during cleaning is determined. If this is done, the amount of combustion is reduced, so that it is possible to obtain an excellent effect that there is no possibility of causing abnormal operation of the absorption chiller / heater caused by washing.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

Embodiment 1
FIG. 1 shows an absorption chiller / heater according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the absorption chiller / heater K includes an absorber 1, an evaporator 2, a condenser 3, a high temperature regenerator 4, a low temperature regenerator 5, a high temperature heat exchanger 6, and a low temperature. The heat exchanger 7, the cooling tower 8, the cleaning device (cleaning means) 10, the combustion device 20, and the control device 30 are provided as main components.

  In the absorption chiller / heater K, similarly to the known absorption chiller / heater, the refrigerant (water) evaporated in the evaporator 2 is absorbed in the absorber 1 with LiBr (lithium bromide) as a main component. To be absorbed. Absorbent liquid (hereinafter referred to as a rare liquid) W having a reduced concentration due to absorption of the refrigerant is preheated by the low temperature heat exchanger 7 and then sent to the low temperature regenerator 5. The dilute liquid W sent to the low-temperature regenerator 5 is heated by the refrigerant vapor from the high-temperature regenerator 4, whereby a part of the refrigerant evaporates to become an intermediate liquid M, which is reserved in the high-temperature heat exchanger 6. After being heated, it is sent to the high temperature regenerator 4.

  The high temperature regenerator 4 has a combustion furnace E as a heating source in which the combustion of the combustion device 20 is performed, and the intermediate liquid M sent to the high temperature regenerator 4 is heated by the combustion of the combustion device 20 in the combustion furnace E. In addition, a concentrated liquid S is obtained in which a part of the refrigerant is evaporated and concentrated. The concentrated liquid S is sent to the high temperature heat exchanger 6 and used as a heating source for the preheating, and then mixed with the intermediate liquid M from the low temperature regenerator 5. The mixed liquid M is sent to the low-temperature heat exchanger 7 and used as a heating source for the preheating, and then sent to the absorber 1 as a sprayed concentrated liquid SS and sprayed in the absorber 1.

  The refrigerant evaporated in the high temperature regenerator 4 (hereinafter referred to as refrigerant vapor) is sent to the low temperature regenerator 5. The refrigerant vapor sent to the low temperature regenerator 5 is used as a heating source for heating the dilute liquid W, and together with the refrigerant vapor evaporated from the dilute liquid W in the low temperature regenerator 5, the refrigerant 3 is cooled with cooling water. It is cooled, liquefied and returned to the refrigerant. This refrigerant is sent to the evaporator 2 and dispersed in the evaporator 2, and vaporizes by removing the heat of vaporization from an object to be cooled such as water. Thereby, water (cold water) as a cooling object is cooled.

  As described above, the refrigerant evaporated in the evaporator 2 is sent to the absorber 1 and absorbed by the absorbing liquid.

  A part of the diluted liquid W from the absorber 1 is sent to an extraction device (not shown), and after the non-condensable gas is extracted, it is returned to the absorber 1.

  The cleaning device 10 has a sponge ball (cleaning ball, hereinafter simply referred to as a ball) for cleaning a heat transfer tube by a flow of cooling water in a circulation system I in which cooling water circulates between the absorber 1, the condenser 3 and the cooling tower 8. (Not shown; see JP-A-5-280889, etc.) is passed through the absorber 1 and the condenser 3, and the heat transfer tube inner surface is wiped by the ball surface to clean the inside of the tube.

  More specifically, the cleaning device 10 includes a ball supply mechanism 11 that supplies the balls to a pipe IF (hereinafter referred to as a cooling water supply pipe) IF that supplies cooling water cooled by the cooling tower 8 to the absorber 1. A ball recovery mechanism 12 that recovers the balls from a pipe (hereinafter referred to as a cooling water return pipe) IR that returns cooling water that has passed through the absorber 1 and the condenser 3 and has cooled the refrigerant to the cooling tower 8; And a cleaning operation unit 14, and a ball supply unit 11 a provided at the tip of the ball supply mechanism 11 is interposed at an appropriate position of the cooling water supply pipe IF, and is attached to the tip of the ball collection mechanism 12. The provided ball collection unit 12a is interposed at an appropriate position of the cooling water return pipe IR.

  Accordingly, the cleaning operation unit 14 starts or stops cleaning according to a command from the control device 30. That is, the cleaning operation unit 14 operates the ball supply mechanism 11 to supply a ball according to the control of the control device 30, passes the ball through the absorber 1 and the condenser 3, and sets the absorber 1 and the condenser 3. The inside of the heat transfer tube is washed, or the ball collecting mechanism 12 is operated to collect the balls and stop the washing.

  The cleaning operation unit 14 may be provided in the control device 30. Further, as the ball supply mechanism 11, the ball collection mechanism 12, and the ball storage mechanism 13, a known ball supply mechanism, a ball collection mechanism, and a ball storage mechanism can be preferably used. Therefore, detailed description of their configurations is omitted. .

  Combustion device 20 includes a burner, a fuel supply mechanism (fuel piping or the like), and a combustion adjustment mechanism (fuel flow rate adjustment valve or the like), and is controlled by control device 30. Since such a burner, a fuel supply mechanism, and a combustion adjustment mechanism can use a well-known burner, a fuel supply mechanism, and a combustion adjustment mechanism suitably, detailed description of those structures is abbreviate | omitted.

  The control device 30 controls the absorption chiller / heater K including the operation unit 31 that operates the start / stop of the absorption chiller / heater K, the control of the cleaning operation unit 14 of the cleaning device 10, and the combustion control of the combustion device 20. The control part 32 which makes | forms, the washing | cleaning schedule management part 33 which manages the washing | cleaning schedule of the washing | cleaning apparatus 10, the driving | running state monitoring part 34 which monitors the driving | running state of the absorption-type cold / hot water machine K during washing | cleaning, and the driving | running state monitoring part 34 As an output means for outputting a processing result of the operation state monitoring unit 34, the cleaning continuation determination unit 35, etc., as well as a built-in cleaning continuation determination unit 35 that determines whether continuation of cleaning is possible based on monitoring information from The image display device 36 is provided.

  Since the operation unit 31 and the control unit 32 are the same as those in a known absorption chiller / heater control device, a detailed description of their configurations is omitted.

  The cleaning schedule management unit 33 has, for example, a schedule relating to the cleaning interval and cleaning time, and outputs a cleaning command according to the schedule to the control unit 32.

  The operation state monitoring unit 34 includes a state index calculating unit 38 and calculates a state index indicating the operation state of the absorption chiller / heater K during the cleaning of the cleaning apparatus 10.

  The state index is calculated by the state index calculating means 38 as follows.

  In the absorption chiller / heater K, the relationship between the cooling load and the high-temperature regenerator pressure is usually a straight line as shown by a solid line in FIG. On the other hand, since the amount of cooling water decreases during cleaning of the cleaning device 10, the relationship between the cooling load and the high-temperature regenerator pressure is a straight line as shown by a broken line in FIG.

  Under such circumstances, when an index f represented by the ratio of the combustion amount Qf and the cooling water heat dissipation amount Qc is introduced, the index f becomes the maximum value fmax at the point where the broken line in FIG. Next, a relative index Rf obtained by dividing the index f by the index (reference index) fo at the point where the solid line in FIG. 4 intersects the operation threshold is introduced. The relative index Rf takes the value 1 at the point where the solid line in FIG. 4 intersects with the driving threshold, and the maximum value Rfmax at the point where the broken line in FIG. 4 intersects with the driving threshold. This means that if the relative index Rf does not exceed the maximum value Rfmax, the hot regenerator pressure will not exceed the operating threshold during cleaning. That is, if the relative index Rf does not exceed the maximum value Rfmax, it can be seen that the absorption chiller / heater K is in a washable state.

  Therefore, it is possible to determine whether or not the cleaning can be continued by appropriately thresholding the relative index Rf. Therefore, in this specification, this relative index Rf is defined as a state index.

  The relative index Rf, that is, the state index, can easily calculate the combustion amount Qf from the fuel flow rate, the cooling water radiation amount Qc can be easily calculated from the inlet / outlet temperature of the cooling water and the cooling water amount, and the cooling load can be calculated from the inlet / outlet of the cooling water. Since it can be easily calculated from the outlet temperature and the amount of cold water, it can be calculated by simple mathematical processing.

  The cleaning continuation determination unit 35 has a cleaning continuation determination threshold, performs a threshold process on the state index to determine whether cleaning can be continued, and outputs the result to the control unit 32. Therefore, when it is determined in this determination that cleaning cannot be continued, the control device 30 outputs a combustion amount reduction command for instructing the combustion device 20 to reduce the combustion amount.

  Here, the threshold value for determining whether or not to continue washing can be set to the maximum value Rfmax, but is set lower than the maximum value Rfmax in consideration of the load condition of the absorption chiller / heater K, seasonal factors, and the like. It is also possible to do. For example, in the absorption chiller / heater K having a heavy load fluctuation, the cleaning continuity determination threshold value is set low, while in the absorption chiller / heater K having a small load fluctuation, the cleaning continuity determination threshold value is set. It can also be set higher. In addition, in the summer season when there is a lot of cooling demand, the threshold value for determining whether or not to continue washing can be set low, while in the spring and autumn season when demand is relatively low, the threshold value for determining whether or not washing can be continued can be set higher.

  In addition, the control apparatus 30 which has this function is implement | achieved as a microcomputer incorporating the program corresponding to the said process, for example.

  Next, the operation of the absorption chiller / heater K having such a configuration will be described with reference to FIG. The following procedure is performed under the control of the control device 30.

  Procedure 1: Start up absorption-type cold / hot water machine K.

  Procedure 2: Absorption type cold / hot water machine K is normally operated.

  Step 3: Set the cleaning schedule. That is, the cleaning interval and the cleaning time are set.

  Procedure 4: The operating conditions of the absorption chiller / heater K are monitored. Specifically, the fuel flow rate, high-temperature regenerator pressure, cooling water inlet / outlet temperature, cooling water amount, cold water inlet / outlet temperature, and cooling water amount are monitored.

  Procedure 5: It is determined whether the high temperature regenerator pressure exceeds the operation threshold value. If the high temperature regenerator pressure exceeds the operation threshold value, the process proceeds to step 13. On the other hand, if the high temperature regenerator pressure does not exceed the operation threshold value, the process proceeds to step 6.

  Procedure 6: Start the cleaning apparatus 10 and start cleaning.

  Procedure 7: A state index is calculated.

  Step 8: Determine whether or not to continue cleaning. If the cleaning can be continued, the process proceeds to step 9, while if the cleaning cannot be continued, the process proceeds to step 13.

  Procedure 9: It is determined whether or not a predetermined cleaning time has elapsed. If the predetermined time has elapsed, the process proceeds to step 10. On the other hand, if the predetermined time has not elapsed, the process returns to step 4.

  Step 10: Finish washing.

  Procedure 11: Count down the number of washings.

  Procedure 12: It is determined whether or not the cleaning schedule is completed. That is, it is determined whether or not the number of remaining cleaning times is zero. If the cleaning schedule has been completed, the process proceeds to step 14. On the other hand, if the cleaning schedule has not been completed, the process returns to step 4.

  Procedure 13: Reduce the amount of combustion and return to Procedure 4.

  Procedure 14: This process is terminated.

  As described above, in the first embodiment, a cleaning schedule can be set regardless of the operation state and load of the absorption chiller / heater K, and cleaning is performed according to the cleaning schedule. Therefore, even if the cleaning device 10 is provided, the operation of the absorption chiller / heater K is not complicated. Further, the high temperature regenerator pressure during cleaning is monitored via a state index, and whether or not the cleaning can be continued is determined based on the state index. If it is determined in the determination that continuation of cleaning is not possible, the amount of combustion is automatically reduced. Therefore, safety during cleaning is also ensured. Therefore, the reduction in the operating rate of the absorption chiller / heater K due to the cleaning of the cleaning device 10 and the adverse effect on the absorption chiller / heater K are minimized.

Embodiment 2
The absorption chiller / heater K1 of the second embodiment of the present invention is a modification of the absorption chiller / heater K of the first embodiment, and the contents of the state index are modified. That is, in the first embodiment, the state index is related to the high temperature regenerator pressure, but in this second embodiment, the state index is related to the high temperature regenerator temperature. Therefore, the state index of the second embodiment can be calculated by the same procedure as the state index of the first embodiment by replacing the high temperature regenerator pressure in FIG. 4 with the high temperature regenerator temperature.

  The remaining configuration of the absorption chiller / heater K1 of the second embodiment is the same as that of the absorption chiller / heater K of the first embodiment.

  Next, the operation of the absorption chiller / heater K1 having such a configuration will be described with reference to FIG. The following procedure is performed under the control of the control device 30.

  Procedure 1: Start up absorption-type cold / hot water machine K.

  Procedure 2: Absorption type cold / hot water machine K is normally operated.

  Step 3: Set the cleaning schedule. That is, the cleaning interval and the cleaning time are set.

  Procedure 4: The operating conditions of the absorption chiller / heater K are monitored. Specifically, the fuel flow rate, the high temperature regenerator temperature, the cooling water inlet / outlet temperature, the cooling water amount, the cold water inlet / outlet temperature, and the cooling water amount are monitored.

  Procedure 5: It is determined whether or not the high temperature regenerator temperature exceeds the operation threshold. If the high temperature regenerator temperature exceeds the operation threshold value, the process proceeds to step 13. On the other hand, if the high temperature regenerator temperature does not exceed the operation threshold value, the process proceeds to step 6.

  Procedure 6: Start the cleaning apparatus 10 and start cleaning.

  Procedure 7: A state index is calculated.

  Step 8: Determine whether or not to continue cleaning. If the cleaning can be continued, the process proceeds to step 9, while if the cleaning cannot be continued, the process proceeds to step 13.

  Procedure 9: It is determined whether or not a predetermined cleaning time has elapsed. If the predetermined time has elapsed, the process proceeds to step 10. On the other hand, if the predetermined time has not elapsed, the process returns to step 4.

  Step 10: Finish washing.

  Procedure 11: Count down the number of washings.

  Procedure 12: It is determined whether or not the cleaning schedule is completed. That is, it is determined whether or not the number of remaining cleaning times is zero. If the cleaning schedule has been completed, the process proceeds to step 14. On the other hand, if the cleaning schedule has not been completed, the process returns to step 4.

  Procedure 13: Reduce the amount of combustion and return to Procedure 4.

  Procedure 14: This process is terminated.

  As described above, in the second embodiment, similarly to the first embodiment, the cleaning schedule can be set regardless of the operation state and load of the absorption chiller / heater K1, and the cleaning is performed according to the cleaning schedule. The Therefore, even if the cleaning device 10 is provided, the operation of the absorption chiller / heater K1 is not complicated. Further, the high temperature regenerator pressure during cleaning is monitored via a state index, and whether or not the cleaning can be continued is determined based on the state index. If it is determined in the determination that continuation of cleaning is not possible, the amount of combustion is automatically reduced. Therefore, safety during cleaning is also ensured. Therefore, the reduction in the operating rate of the absorption chiller / heater K1 and the adverse effect on the absorption chiller / heater K1 due to the cleaning of the cleaning device 10 are minimized.

  The present invention can be applied to an absorption chiller / heater including an absorption chiller.

It is the schematic of the absorption type cold / hot water machine which concerns on embodiment of this invention. It is a block diagram of the washing | cleaning apparatus of the embodiment. It is a block diagram of the control device of the embodiment. It is a graph which shows typically the relationship between a cooling load and a high temperature regenerator pressure. It is a flowchart which shows the operation | movement procedure of the absorption type cold / hot water machine of the embodiment. It is a flowchart which shows the operation | movement procedure of the absorption-type cold / hot water machine of Embodiment 2 of this invention.

Explanation of symbols

K Absorption Type Chilled and Hot Water Machine 1 Absorber 3 Condenser 4 High Temperature Regenerator 8 Cooling Tower 10 Cleaning Device 11 Ball Supply Mechanism 12 Ball Recovery Mechanism 13 Ball Storage Mechanism 14 Cleaning Operation Unit 20 Combustion Device 30 Control Device 33 Cleaning Schedule Setting Unit 34 Operation state monitoring unit 35 Washing continuation determination unit 38 State index calculation means

Claims (3)

An absorption chiller / heater comprising a cleaning device and a combustion device,
The absorption chiller / heater control device includes a cleaning schedule management unit, an operation state monitoring unit having a state index calculation unit, and a cleaning continuation determination unit.
The state index calculating means calculates a relative index obtained by dividing a state index represented by a ratio between a combustion amount during operation and a cooling water heat release amount by a maximum value of the state index,
The cleaning continuation determination unit has a cleaning continuation determination threshold ,
The cleaning continuation determination unit, to the relative index na determines cleaning continuation determination during operation by the threshold processing by the washing continuation determination threshold,
Wherein if the determination of the cleaning not is made in decision, the control device, the absorption chiller-heater according to claim also be output from the combustion amount reduction command for commanding a reduction in combustion quantity of the combustion device. The absorption chiller / heater according to claim 1, wherein the washing continuation determination threshold is changeable based on a load condition of the absorption chiller / heater or a seasonal factor. An operation method of the absorption chiller / heater according to claim 1 or 2 ,
The procedure for setting the cleaning schedule;
Procedures for monitoring the operating conditions of the absorption chiller / heater,
Start the cleaning device and start cleaning,
A procedure for calculating a relative index;
A procedure for determining whether or not cleaning can be continued during operation by performing threshold processing on the relative index according to a threshold for determining whether or not cleaning can be continued;
The method for operating an absorption chiller / heater includes a procedure for reducing the amount of combustion of the combustion device when it is determined in the determination that continuation of washing is not possible.

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