JP2018017477A - Air conditioning system and operation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict cut-off of water stopping due to excessive flow rate when a heat source machine is changed over at the time of increasing the number of stages of the heat source machine.SOLUTION: This invention relates to an air conditioning system 100 comprising a communicating pipe 11 communicating between a first feeding header 4 and a second returning header 10 and the same flow rate as the maximum rated flow rate of freezers 1A, 1B, 1C are stored in advance and a control device 13 for changing-over operations of the freezers 1A, 1B and 1C on the basis of the operation combination. The control device 13 starts an operation of the freezer after its changing-over after the freezer being operated is stopped under a case in which it satisfies a condition in which [flow rate during operation + additional flow rate - maximum communication flow rate]>a load flow rate is attained under an assumption that a return flow rate detected by a flow meter 22 is applied as a load flow rate, a total rated flow rate of the freezer in operation is applied as a flow rate in operation and a total of rated flow rate of the additional freezer by changing-over in operation of the freezer is applied as a flow rate after being changed over.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air conditioning system and an operation control method, and more particularly to an operation control method for controlling the operation of a plurality of heat source devices in an air conditioning system based on a flow rate of a thermal fluid returned from a load device to a return header.

  There are air conditioning systems installed in factories and buildings. The air conditioning system includes a plurality of heat source devices that generate a thermal fluid such as cold water cooled to a predetermined temperature, a feed header that is supplied with the thermal fluid from the plurality of heat source devices, and an air conditioner that is supplied with the thermal fluid from the feed header. Based on a load device such as a device, a return header to which the heat fluid exchanged in the load device is returned, a communication pipe communicating the feed header and the return header, and a flow rate of the thermal fluid returned from the load device to the return header And a control device for controlling the operation of the plurality of heat source devices. A plurality of refrigerators having different rated flow rates are used for the plurality of heat source devices.

  In this air conditioning system, when the flow rate of the heat fluid returned from the load device increases and it is necessary to increase the heat source device, the control device starts from the operating heat source device to the rated flow rate of the operating heat source device. Switch to heat source equipment with a larger rated flow. At this time, after starting the operation of the heat source device to be operated next, an overlap operation for stopping the heat source device in operation is performed (see, for example, Patent Document 1). According to this overlap operation, when the flow rate of the heat fluid returned from the load device increases, when the heat source device is increased, the currently operating heat source device and the next scheduled heat source device are temporarily Since the operation is performed in an overlapping manner, the thermal fluid maintained at a predetermined temperature can be supplied to the load device without interruption.

JP 59-9442 A

  In the overlap operation described in Patent Literature 1, the heat source device being operated and the heat source device scheduled to be operated next are overlapped and operated. During this overlap operation, the heat fluid is supplied to the load device by both the heat source devices, so that a large amount of heat fluid is temporarily supplied to the load device. The supply amount exceeding the flow rate of the thermal fluid required by the load device is returned from the feed header to the return header through the communication pipe and returned to the heat source device.

  However, when the maximum communication flow rate of the communication pipe is small, that is, when it is difficult to sufficiently return the thermal fluid from the feed header to the return header, the supply amount of the thermal fluid from the heat source device is required by the load device. The total flow rate of the thermal fluid flow and the maximum communication flow rate of the communication pipe is exceeded, and the thermal fluid cannot return to the return header, making it difficult to return the thermal fluid to the heat source device. This state is called an excessive flow rate in the feed header. If this excessive flow rate occurs, the flow rate of the thermal fluid is insufficient on the upstream side of the heat source device, and the heat source device may issue a water stop alarm and stop the water stop.

  Therefore, an object of the present invention is to suppress water stoppage due to excessive flow rate when the heat source device is switched when the heat source device is increased.

The air conditioning system of the present invention includes a plurality of heat source devices that generate a thermal fluid, a feed header that collects the thermal fluids from the plurality of heat source devices, a load device that is supplied with the thermal fluid from the feed header, A return header that distributes the thermal fluid heat-exchanged in the load device to the plurality of heat source devices, a flow rate detector that detects a return flow rate of the thermal fluid returned from the load device to the return header, and the feed An operation combination of a plurality of heat source devices based on the return flow rate of the thermal fluid, and a communication pipe that communicates the header and the return header and sets the maximum rated flow rate and the same flow rate of the heat source devices as the maximum communication flow rate. Is stored in advance, and a control device that switches operation of the plurality of heat source devices based on the operation combination, wherein the control device The return flow detected by the detector is the load flow, the total rated flow of the heat source equipment in operation is the operating flow, and the total rated flow of the heat source equipment added by switching the operation of the heat source equipment is When the additional flow rate
(In-operation flow rate + additional flow rate−maximum communication flow rate)> When the condition of load flow rate is satisfied, the operation of the heat source device after switching is started after the heat source device in operation is stopped.

The air conditioning system of the present invention includes a plurality of heat source devices that generate thermal fluid, a feed header that collects the thermal fluids from the plurality of heat source devices, and a load device that is supplied with the thermal fluid from the feed header. A return header that distributes the thermal fluid heat-exchanged in the load device to the plurality of heat source devices, and a flow rate detector that detects a return flow rate of the thermal fluid returned from the load device to the return header, A communication pipe that communicates the feed header and the return header, the maximum rated flow rate of the plurality of heat source devices and the same flow rate as the maximum communication flow rate, and a plurality of the heat source devices based on the return flow rate of the thermal fluid. An air conditioning system that stores an operation combination in advance and includes a control device that switches operation of the plurality of heat source devices based on the operation combination, and the control device includes: The return flow detected by the flow rate detector is a load flow rate, there are a plurality of operating heat source devices, the total of the rated flow rates of the plurality of heat source devices is the operating flow rate, and by switching the operation of the heat source device When the total rated flow rate of the heat source equipment to be added is the additional flow rate,
(Operating flow rate + additional flow rate-maximum communication flow rate)> When the condition of load flow rate is satisfied,
(In-operation flow rate + additional flow rate-load flow rate) <part of the operating heat source device that satisfies the condition of the maximum communication flow rate is stopped, and the operation of the added heat source device is started, and then the remaining operation The heat source device inside is stopped.

The operation control method of the present invention includes a plurality of heat source devices that generate a thermal fluid, a feed header that collects the thermal fluids from the plurality of heat source devices, and a load to which the thermal fluid is supplied from the feed header. A return header that distributes the thermal fluid heat-exchanged in the load device to the plurality of heat source devices, and a flow rate detector that detects a return flow rate of the thermal fluid returned from the load device to the return header. The return flow rate of the thermal fluid is applied to an air conditioning system including a communication pipe that connects the feed header and the return header, and has a maximum communication flow rate that is the same as the maximum rated flow rate of the plurality of heat source devices. An operation control method for switching the operation of the plurality of heat source devices based on the operation combination of the plurality of heat source devices based on the method, wherein the return flow rate detected by the flow rate detector is negative. When the flow rate, the sum of the rated flow of the heat source device during operation and during operation the flow rate and the sum of the rated flow rate of the heat source device to be added by switching operation of the heat source device and post-switching rate,
(In-operation flow rate + additional flow rate−maximum communication flow rate)> When the condition of load flow rate is satisfied, the operation of the heat source device after switching is started after the heat source device in operation is stopped.

  ADVANTAGE OF THE INVENTION According to this invention, when switching a heat source apparatus at the time of the stage increase of a heat source apparatus, the water-stop stop by excessive flow volume can be suppressed.

1 is a schematic configuration diagram of a two-pump air conditioning system in a first embodiment. It is a flowchart which shows the process by the control apparatus in 1st Embodiment. It is a flowchart which shows the process by the control apparatus in 1st Embodiment. It is a table which shows the relationship of the load flow volume in 1st Embodiment, the flow volume during driving | operation, and the communication pipe flow volume. It is a flowchart which shows the process by the control apparatus in 2nd Embodiment. It is a part of table | surface which shows the relationship of the load flow volume in 2nd Embodiment, the flow volume during driving | operation, and a communicating pipe flow volume. It is a part of table | surface which shows the relationship of the load flow volume in 3rd Embodiment, the flow volume during driving | operation, and a communicating pipe flow volume.

  A two-pump air conditioning system 100 showing the first embodiment will be described. The air conditioning system 100 is a central air conditioning system used for air conditioning of large facilities such as factories, buildings, and shopping malls. In the air conditioning system 100, a plurality of refrigerators 1A, 1B, 1C (heat source devices) are centrally installed in one place, and cold water (thermal fluid) cooled by these refrigerators 1A, 1B, 1C is air conditioners 7A, 7B, 7C. Air is supplied to (load equipment) for air conditioning.

  As shown in FIG. 1, an air conditioning system 100 includes a plurality of refrigerators 1A, 1B, and 1C arranged in parallel, primary chilled water pumps 2A, 2B, and 2C provided in the refrigerators 1A, 1B, and 1C, respectively, A plurality of secondary chilled water pumps 5A, 5B, 5C, 5D connected to the water supply pipes 3A, 3B, 3C on the outlet side of the machines 1A, 1B, 1C via the first feed header 4, and secondary chilled water pumps A plurality of air conditioners 7A, 7B, and 7C connected to 5A, 5B, 5C, and 5D via the second feed header 6 and the water pipes 3A, 3B, and 3C and arranged in parallel, and the air conditioners 7A, 7B, and 7C And the first return header 9 and the second return header 10 connected via the return water pipes 8A, 8B, and 8C, and the communication pipe 11 that connects the first feed header 4 and the second return header 10. A throttle valve 12 provided in the communication pipe 11 and an air conditioner Control device 13 for controlling the number of operating refrigerators 1A, 1B, 1C, primary chilled water pumps 2A, 2B, 2C and secondary chilled water pumps 5A, 5B, 5C, 5D according to the load conditions of A, 7B, 7C. And.

  Between the first feed header 4 and the second feed header 6, the cold water of the second feed header 6 is converted into secondary cold water by the differential pressure between the second feed header 6 and the first feed header 4. A bypass valve 14 for returning to the pumps 5A, 5B, 5C, 5D is provided.

The rated flow rates of the refrigerators 1A, 1B, and 1C are different from each other. For example, the rated flow rate of the refrigerator 1A is 170 m ³ / h, the rated flow rate of the refrigerator 1B is 80 m ³ / h, and the rated flow rate of the refrigerator 1C is It is set to 50 m ³ / h. Further, the maximum communication flow rate of the communication pipe 11 is set to 170 m ³ / h which is substantially the same as the maximum rated flow rate of the refrigerators 1A, 1B, 1C.

  The air conditioning system 100 includes a plurality of detection devices for detecting the state of cold water flowing through the air conditioning system 100. That is, the air conditioning system 100 includes a feed header temperature sensor 20 that detects the temperature of the cold water in the second feed header 6 and a return water temperature sensor 21 that detects the temperature of the cold water heat-exchanged in the air conditioners 7A, 7B, and 7C. And a flow meter 22 as a flow rate detector that detects the flow rate of cold water (load flow rate) that is returned after heat exchange in the air conditioners 7A, 7B, and 7C, and a return that detects the temperature of the cold water in the second return header 10. And a header temperature sensor 23. The return water temperature sensor 21 and the flow meter 22 are respectively provided between the first return header 9 and the second return header 10.

  These detection devices are electrically connected to the control device 13, and the detection result is input to the control device 13. The control device 13 is also electrically connected to the refrigerators 1A, 1B, 1C, primary chilled water pumps 2A, 2B, 2C, and secondary chilled water pumps 5A, 5B, 5C, 5D.

  The control device 13 controls the number of operating refrigerators 1A, 1B, 1C based on the load state of the air conditioners 7A, 7B, 7C, the input detection result, an instruction from a control panel (not shown), and the primary cold water. Direct digital controller (DDC) 13a for controlling the pumps 2A, 2B, 2C and the secondary chilled water pumps 5A, 5B, 5C, 5D, the rated flow rate of each refrigerator 1A, 1B, 1C and the maximum communication flow rate of the communication pipe 11 Are stored in the storage unit 13b. The storage unit 13b also stores a program for the DDC 13a to control the number of operating refrigerators 1A, 1B, and 1C. That is, in the present embodiment, an operation combination for operating the refrigerators 1A, 1B, and 1C is stored so as to always exceed the cold water flow rate (load flow rate) detected by the flow meter 22. The storage unit 13b includes a hard disk drive (HDD), a random access memory (RAM), and the like.

  Specifically, the operation combinations of the refrigerators 1A, 1B, and 1C shown in FIG. 4 are stored. In the air conditioning system 100, it is necessary to always supply chilled water exceeding the load flow rate, and the operation is started in order from the refrigerator 1C having a smaller rated flow rate, and the refrigeration is performed when the rated flow rate of the refrigerator 1C is insufficient with respect to the load flow rate. When the total flow rate of the refrigerators 1B and 1C is insufficient, the refrigerator 1A is increased in place of the refrigerators 1B and 1C. Further, when the load flow rate increases, the refrigerator 1B or the refrigerator 1C is added to the refrigerator 1A, and when the load flow rate further increases, all of the refrigerators 1A, 1B, 1C are operated. . Further, when the load flow rate is decreased, control is performed to decrease in the reverse order to the above-described increase.

  Further, the control device 13 has the following four operation control methods when increasing the number of stages of the refrigerators 1A, 1B, and 1C, depending on the load flow rate, the operation status of the refrigerators 1A, 1B, and 1C, and the like. Four control methods are used properly. That is, after stopping the operating freezer, the control device 13 stops the operating prioritized control for starting the operation of the switched freezer and the operating freezer after a predetermined time after starting the switched freezer operation. Operation priority control, continuous operation control to start the operation of the additional refrigerator while continuing all the operations of the operating refrigerator, and the operation of the additional refrigerator while continuing a part of the operation of the operating refrigerator And partly continuous operation control to start. A detailed description of how to use these four operation control methods will be described later. The in-operation refrigerator means a refrigerator that is currently in operation, the post-switching refrigerator means a refrigerator that is operated after switching operation, and the additional refrigerator is added by switching operation. Means a freezer.

  The general flow of cold water in the air conditioning system 100 will be described. The cold water pumped by the primary cold water pumps 2A, 2B, 2C is cooled in the refrigerators 1A, 1B, 1C and sent to the first feed header 4. In the first feed header 4, the cold water pumped by the primary cold water pumps 2A, 2B, 2C is gathered. The chilled water in the first feed header 4 is pumped by the secondary chilled water pumps 5A, 5B, 5C, 5D and sent to the air conditioners 7A, 7B, 7C via the second feed header 6 and the water feed pipes 3A, 3B, 3C. Sent. The cold water supplied to the air conditioners 7A, 7B, and 7C is subjected to heat exchange in the air conditioners 7A, 7B, and 7C, and passes through the return pipes 8A, 8B, and 8C, the first return header 9, and the second return header 10. To the primary cold water pumps 2A, 2B, 2C. The chilled water that has returned to the primary chilled water pumps 2A, 2B, and 2C is again pumped by the primary chilled water pumps 2A, 2B, and 2C, and the first feed header 4, the second feed header 6, and the air conditioners 7A and 7B. , 7C, the first return header 9 and the second return header 10 are circulated.

  Next, the operation switching control of the refrigerators 1A, 1B, and 1C by the control device 13 will be described with reference to the flowcharts shown in FIGS. 2 and 3 and the table shown in FIG. In the table shown in FIG. 4, the flow rate detected by the flow meter 22 is the load flow rate, the total of the rated flow rates of the operating refrigerators 1A, 1B, and 1C is the operating flow rate, and the load flow rate, the operating flow rate, and the communication pipe 11 The flow rate relationship is shown.

  In step S100 of FIG. 2, the detection result of the flow meter 22 is acquired, and the process proceeds to step S101. The cold water flow rate detected by the flow meter 22 is a load flow rate in the air conditioners 7A, 7B, and 7C. In step S101, the rated flow rate of the operating refrigerator is totaled to obtain the operating flow rate, and the process proceeds to step S102.

  In step S102, the load flow rate and the operating flow rate are compared. As a result of the comparison, if the load flow rate is larger than the operating flow rate (Yes), the process proceeds to step S103. In step S103, the operating flow rate does not satisfy the load flow rate. It is determined that an additional stage is necessary, and the process proceeds to step S104.

  In step S104, the total rated flow rate of the chiller after the stage increase is calculated before the stage increase of the chiller. Here, a case will be described in which the sum of the rated flow rates of the additional refrigerators added by the stage increase is calculated before the stage increase of the refrigerator. The additional refrigerator to be added next can be grasped by the combination of the refrigerator operations stored in advance. If there are multiple additional refrigerators to be added next, calculate the sum of the rated flow rates of those additional refrigerators as the additional flow rate, and if there is one additional refrigerator to be added next, the rated flow rate of that additional refrigerator To the step S105 shown in FIG.

In step S105, it is determined whether the following conditional expression X is satisfied.
(Flow during operation + Additional flow-Maximum communication flow)> Load flow ... Conditional expression X

  That is, the flow rate obtained by subtracting the maximum communication flow rate of the communication pipe 11 from the flow rate obtained by adding the operating flow rate calculated in step S101 and the additional flow rate calculated in step S104 is compared with the load flow rate detected in step S100. In step S105, when the conditional expression X is satisfied (Yes), the process proceeds to step S106. In step S106, the additional flow rate is compared with the load flow rate. As a result of the comparison, when the additional flow rate is larger than the load flow rate (Yes), the process proceeds to step S107 and stop priority control is performed. That is, after stopping the freezer during operation, the operation of the additional freezer that is the post-switching freezer is started, and the series of controls is completed.

  In step S106, if the additional flow rate is equal to or lower than the load flow rate (No), the process proceeds to step S108 where partial continuous operation control is performed. That is, in step S108, since the load flow rate cannot be covered only by the additional flow rate, it is necessary to supply a part of the operation flow rate. For this reason, when the operating flow rate is the sum of a plurality of operating refrigerators, among the operating refrigerators supplying the operating flow rate, the operating refrigerator that can provide a flow rate difference of (load flow rate−additional flow rate) The chiller is stopped during other operations. Then, the operation of the additional refrigerator is started and the flowchart is ended.

Here, the reason why the conditional expression X is determined in step S105 when increasing the number of refrigerators will be described with reference to the numerical values in the table of FIG. As indicated by the change from the symbol E1 to the symbol E2 in FIG. 4, when the detection result (load flow rate) of the flow meter 22 increases from 120 m ³ / h to 130 m ³ / h, the refrigerator operated until then The operating flow rate of 130 m ³ / h, which is the sum of the rated flow rates of 1B and 1C, is not sufficient, and it is necessary to increase (add) the refrigerator 1A. At this time, when the refrigerator 1A is added, if the above-described operation priority control is performed, the three refrigerators 1A, 1B, and 1C are temporarily operated simultaneously as indicated by reference numeral E2. By these operations, the first feed header 4 is supplied with chilled water having a total rated flow rate of 300 m ³ / h of the refrigerators 1A, 1B, and 1C.

Since the load flow rate required in the air conditioners 7A, 7B, and 7C is 130 m ³ / h, other cold water (flow rate 170 m ³ / h) is returned to the second return header 10 through the communication pipe 11. However, since the maximum communication flow rate of the communication pipe 11 is 170 m ³ / h, the communication pipe 11 is filled with cold water, resulting in an excessive flow rate, and the cold water cannot be completely returned to the second return header 10. The flow rate of cold water is insufficient on the upstream side of the cold water pumps 2A, 2B, 2C. If this state continues, the air conditioning system 100 may issue a water stop alarm in the refrigerators 1A, 1B, 1C and the primary chilled water pumps 2A, 2B, 2C and stop the water stop. For this reason, when this condition is judged by the above-mentioned conditional expression X and the conditional expression X is satisfied, that is, when the flow rate is excessive, as shown by the symbol E3 in FIG. I do.

In this stop priority control, first, the operating refrigerators 1A, 1B, and 1C are stopped as indicated by reference numeral E3 in FIG. When the refrigerators 1A, 1B, and 1C are stopped, the flow rate during operation by the refrigerators 1A, 1B, and 1C becomes 0 m ³ / h, and the communication pipe flow rate temporarily becomes 0 m ³ / h. And only the refrigerator 1A required in order to cover a load flow volume is drive | operated as shown with the code | symbol E4 of FIG. By performing this stop priority control, to the load flow 130m ³ / h, rated flow 170m ³ / h of the refrigerator 1A is supplied cold water exceeding the load flow 130m ³ / h (flow rate 40 m ³ / h) is It is returned to the second return header 10 via the communication pipe 11.

  On the other hand, in step S102, when the load flow rate is smaller than the operating flow rate (No), since the load flow rate can be supplied by the current operating refrigerator, the operation of the current operating refrigerator is maintained. To end the series of controls.

  In Step S105, when the conditional expression X is not satisfied (No), that is, when it is unlikely that the water stoppage is stopped, the process proceeds to Step S109. In step S109, the additional flow rate is compared with the load flow rate. As a result of the comparison, when the additional flow rate is higher than the load flow rate (Yes), the process proceeds to step S110, and in step S110, the operating refrigerator is stopped after a predetermined time after the operation of the additional refrigerator that is the switched refrigerator is started. Perform operation priority control. In this operation priority control, the refrigerator during operation and the additional refrigerator are operated so as to overlap for a predetermined time.

Specific control in steps S109 and S110 will be described with reference to FIG. As indicated by reference numerals F1 and F2, when the detection result (load flow rate) of the flow meter 22 increases from 40 m ³ / h to 50 m ³ / h, the rated flow rate 50 m ³ / h of the operating refrigerator 1C is insufficient. It is necessary to increase the stage of the refrigerator 1B (rated flow rate 80 m ³ / h). At this time, since the additional flow rate is larger than the load flow rate, after the addition of the refrigerator 1B, the cold water supply by the operating refrigerator 1C is not necessary, and the refrigerators 1B and 1C are switched when switching from the refrigerator 1C to the refrigerator 1B. After performing the overlap operation for a predetermined time, the operating refrigerator 1C is stopped (see symbol F3). Further, similar operation priority control is performed in the portion indicated by the reference symbol G.

  In step S109, when the additional flow rate is equal to or lower than the load flow rate (No), the process proceeds to step S111. In step S111, continuous priority control is performed to start the operation of the additional refrigerator while continuing the operation of the operating refrigerator. In this continuous priority control, an additional refrigerator is added to the operating refrigerator and both refrigerators are operated.

Specific control in steps S109 and S111 will be described with reference to FIG. As indicated by reference numerals H1 and H2, when the detection result (load flow rate) of the flow meter 22 increases from 70 m ³ / h to 80 m ³ / h, the operating flow rate 80 m ³ that is the rated flow rate of the operating refrigerator 1B. / H becomes insufficient, and it is necessary to increase (add) the refrigerator 1C. At this time, since only the additional refrigerator 1C cannot cover the load flow rate, it is necessary to operate the two refrigerators 1B and 1C in order to cover the load flow rate. For this reason, the additional refrigerator 1C is added to the operating refrigerator 1B, and cold water exceeding the load flow rate is supplied by these refrigerators 1B and 1C (see reference H2). Further, similar continuous operation control is performed in the portions indicated by the symbols J and K.

  In this way, as indicated by the symbol E2 in FIG. 4, when the stage of the refrigerator is increased, the possibility that the water supply is stopped due to excessive flow rate is determined by the conditional expression X, and when the possibility of the water supply stop is high, the stop priority control is performed. The flow rate excess in the 1st feed header 4 is suppressed, and the shortage of the cold water flow rate in the upstream of the refrigerators 1A, 1B, 1C and the primary chilled water pumps 2A, 2B, 2C is suppressed. As a result, it is possible to prevent the water stoppage by preventing the water stop alarm from being issued.

  Although cold water was supplied to the air conditioners 7A, 7B, 7C using the refrigerators 1A, 1B, 1C as the heat source equipment, hot water was supplied to the air conditioners 7A, 7B, 7C using a boiler or the like as the heat source equipment. May be. The present invention can also be applied to a one-pump air conditioning system.

  Next, a second embodiment will be described with reference to FIGS. Parts similar to those of the first embodiment described with reference to FIGS. 1 to 4 are denoted by the same reference numerals and description thereof is omitted.

  In the second embodiment, it is assumed that there are a plurality of operating refrigerators. Since the combination of operating refrigerators is stored in the storage unit 13b of the control device 13, the number of operating refrigerators can be grasped based on this combination.

  In the second embodiment, the process up to step S106 in FIG. 5 is the same as in the first embodiment. As a result of comparing the additional flow rate and the load flow rate in step S106, the additional flow rate is greater than the load flow rate (Yes). Proceed to step S120.

  In step S120, since the additional flow rate exceeds the load flow rate, it is not necessary to continuously operate the operating refrigerator as in step S108. However, when switching the operation of the refrigerator, all the refrigerators are temporarily turned on. Since it may be difficult to maintain the cold water temperature by stopping, a part of the refrigerator during operation is continuously operated to prevent this. For this reason, among the plurality of operating refrigerators, the operation of some of the operating refrigerators is continued, and the other operating refrigerators are stopped. At the same time, the operation of the additional refrigerator is started, and the process proceeds to step S121.

In step S120, among the plurality of operating refrigerators, selection of a refrigerator that continues operation and a refrigerator that stops operation is performed based on the following conditional expression Y.
(Operating flow rate + additional flow rate-load flow rate) <maximum communication flow rate ··· Conditional Y
That is, among the plurality of operating refrigerators, the operating refrigerator satisfying the conditional expression Y is stopped and the operation of the other operating refrigerators is continued so as not to cause an excessive flow rate in the first feed header 4. To do.

  In step S121, it is confirmed that the operation of the additional refrigerator is started, and the rest of the operating refrigerator is stopped. Then, a series of control is complete | finished.

Specific control in steps S120 and S121 will be described with reference to FIG. As the sign L1 in FIG 6 illustrates a change in the code L2, the detection result of the flow meter 22 (load flow) is 120 m ³ / If was increased to 130m ³ / h from h, the refrigerator was driving until then The operating flow rate of 130 m ³ / h, which is the sum of the rated flow rates of 1B and 1C, is not sufficient, and it is necessary to increase the number of stages of the refrigerator 1A.

  At this time, based on the conditional expression Y, the operation of either one of the refrigerators 1B and 1C is continued and the other is stopped. In the case shown in FIG. 6, the condition formula Y is satisfied regardless of which of the refrigerators 1B and 1C is stopped, so the operation of the refrigerator 1B is continued and the refrigerator 1C is stopped. With the stop of the refrigerator 1C, the primary cold water pump 2C is also stopped, and after the primary cold water pump 2C is stopped, the operation of the refrigerator 1A is started.

As shown at L2, refrigerator 1A, 1B is operated, to the load flow (130m ³ / h), the refrigerator 1A, 1B sum of rated flow of (250m ³ / h) is supplied, this The cold water (flow rate 120 m ³ / h) other than is returned to the second return header 10 through the communication pipe 11. Thereafter, as indicated at L3, since the refrigerator 1B is also stopped, to the load flow (130m ³ / h), the rated flow of the refrigerator 1A (170m ³ / h) is supplied.

  As described above, in the second embodiment, according to the conditional expression Y, among the plurality of operating refrigerators, the operation of some of the operating refrigerators is continued, and the other operating refrigerators are replaced. Since it stops, the chilled water temperature at the time of refrigerating stage addition can be maintained. As a result, excessive flow rate in the first feed header 4 can be suppressed, and the chilled water temperature when the refrigerator is increased can be maintained.

Next, a third embodiment will be described with reference to FIG. In the third embodiment, five refrigerators 1D, 1E, 1F, 1G, and 1H are provided instead of the three refrigerators 1A, 1B, and 1C in FIG. The refrigerators 1D, 1E, 1F, 1G, and 1H have the same rated flow rate (100 m ³ / h). Further, the order of operation is determined in advance, and the stages are increased in the order of the refrigerators 1D, 1E, 1F, 1G, and 1H according to the load flow rate. When stepping down, step down in the reverse order. The maximum communication flow rate of the communication pipe 11 is set to 100 m ³ / h, which is substantially the same as the maximum rated flow rate of the refrigerators 1D, 1E, 1F, 1G, 1H.

As indicated by reference numeral M1 in FIG. 7, when the detection result (load flow rate) of the flow meter 22 is 350 m ³ / h, the refrigerators 1D, 1E, 1F, 1G are operated according to a predetermined operation sequence, A total flow rate of these refrigerators, 400 m ³ / h, is supplied. As a result, cold water (flow rate 50 m ³ / h) exceeding the load flow rate 350 m ³ / h is returned to the second return header 10 via the communication pipe 11.

As indicated by reference numeral M2 in FIG. 7, when the refrigerator 1G fails, the refrigerator 1H is operated instead of the refrigerator 1G. That is, the refrigerator 1H is operated as an alternative operation of the refrigerator 1G. Thereafter, as shown by the symbol M3 in FIG. 7, when the repair of the refrigerator 1G is completed and the refrigerator 1G is restored, both the refrigerators 1G and 1H are temporarily operated. That is, in this case, all of the refrigerators 1D, 1E, 1F, 1G, and 1H are operated. As a result, cold water (flow rate 150 m ³ / h) exceeding the load flow rate 350 m ³ / h is returned to the second return header 10 via the communication pipe 11. However, since the maximum communication flow rate of the communication pipe 11 is 100 m ³ / h, the communication pipe 11 is filled with cold water, resulting in an excessive flow rate. If this state continues, the air conditioning system 100 may issue a water stop alarm and stop the water stop. For this reason, when the refrigerator 1G is restored, as shown by the symbol M4 in FIG. 7, the operation of the refrigerator 1G is performed after the refrigerator 1H and the primary chilled water pump (not shown) of the refrigerator 1H are stopped. To start.

  In this way, even when the refrigerators 1D, 1E, 1F, 1G, and 1H have the same rated flow rate, as shown by the symbols M2 and M3 in FIG. When the possibility is high, and when such a case is detected, an excessive flow rate due to the step increase is suppressed. As a result, it is possible to prevent the water stoppage by preventing the water stop warning from being caused by excessive flow rate.

1A, 1B, 1C refrigerator, 2A, 2B, 2C primary chilled water pump, 3A, 3B, 3C water pipe, 4 first feed header, 5A, 5B, 5C, 5D secondary chilled water pump, 6 second feed Header, 7A, 7B, 7C Air conditioner, 8A, 8B, 8C Return pipe, 9 First return header, 10 Second return header, 11 Communication pipe, 12 Throttle valve, 13 Control device, 13a DDC, 13b Storage unit , 14 Bypass valve, 20 Feed header temperature sensor, 21 Return water temperature sensor, 22 Flow meter, 23 Return header temperature sensor, 100 Air conditioning system, X, Y Conditional expression.

Claims (3)

A plurality of heat source devices for generating a thermal fluid;
A feed header that collects the thermal fluid from a plurality of the heat source devices;
A load device to which the thermal fluid is supplied from the feed header;
A return header that distributes the thermal fluid heat-exchanged in the load device to the plurality of heat source devices;
A flow rate detector for detecting a return flow rate of the thermal fluid returned from the load device to the return header;
A communication pipe that connects the feed header and the return header, and has a maximum communication flow rate that is the same as the maximum rated flow rate of the plurality of heat source devices,
A control device that previously stores an operation combination of the plurality of heat source devices based on the return flow rate of the thermal fluid, and switches the operation of the plurality of heat source devices based on the operation combination;
An air conditioning system comprising:
The controller is
The return flow rate detected by the flow rate detector is a load flow rate, the total rated flow rate of the operating heat source device is the operating flow rate, and the rated flow rate of the heat source device is added by switching the operation of the heat source device. When the total flow is an additional flow rate,
(Operating flow rate + additional flow rate−maximum communication flow rate)> When the condition of load flow rate is satisfied, after the heat source device being operated is stopped, the operation of the heat source device after switching is started. system. A plurality of heat source devices for generating a thermal fluid;
A feed header that collects the thermal fluid from a plurality of the heat source devices;
A load device to which the thermal fluid is supplied from the feed header;
A return header that distributes the thermal fluid heat-exchanged in the load device to the plurality of heat source devices;
A flow rate detector for detecting a return flow rate of the thermal fluid returned from the load device to the return header;
A communication pipe that connects the feed header and the return header, and has a maximum communication flow rate that is the same as the maximum rated flow rate of the plurality of heat source devices,
A control device that previously stores an operation combination of the plurality of heat source devices based on the return flow rate of the thermal fluid, and switches the operation of the plurality of heat source devices based on the operation combination;
An air conditioning system comprising:
The controller is
The return flow rate detected by the flow rate detector is a load flow rate, and there are a plurality of operating heat source devices, the total of the rated flow rates of the plurality of heat source devices is the operating flow rate, and by switching the operation of the heat source device When the total rated flow rate of the heat source equipment to be added is the additional flow rate,
(Operating flow rate + additional flow rate-maximum communication flow rate)> When the condition of load flow rate is satisfied,
(In-operation flow rate + additional flow rate-load flow rate) <part of the operating heat source device that satisfies the condition of the maximum communication flow rate is stopped, and the operation of the added heat source device is started, and then the remaining operation An air conditioning system characterized in that the heat source device is stopped. A plurality of heat source devices for generating a thermal fluid;
A feed header that collects the thermal fluid from a plurality of the heat source devices;
A load device to which the thermal fluid is supplied from the feed header;
A return header that distributes the thermal fluid heat-exchanged in the load device to the plurality of heat source devices;
A flow rate detector for detecting a return flow rate of the thermal fluid returned from the load device to the return header;
A communication pipe that connects the feed header and the return header, and has a maximum communication flow rate that is the same as the maximum rated flow rate of the plurality of heat source devices,
An operation control method for switching operation of a plurality of heat source devices based on an operation combination of the plurality of heat source devices based on the return flow rate of the thermal fluid,
The return flow rate detected by the flow rate detector is a load flow rate, the total rated flow rate of the operating heat source device is the operating flow rate, and the rated flow rate of the heat source device is added by switching the operation of the heat source device. When the total is the flow rate after switching,
(Operating flow rate + additional flow rate−maximum communication flow rate)> When the condition of load flow rate is satisfied, after the heat source device in operation is stopped, the operation of the heat source device after switching is started. Control method.

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