Cooperative control method and device for internal and external circulation of chilled water system

Abstract

The invention relates to an internal and external circulation cooperative control method and device for a chilled water system, and belongs to the technical field of industrial refrigeration control. The method comprises the steps that the high-temperature area water level and the low-temperature area water level of an open type water tank are collected in real time; determining the water level difference between the high-temperature area water level and the low-temperature area water level of the open water tank; controlling the water level difference within a set threshold range as a first priority control target, and dynamically adjusting the total flow of the internal circulating pump set and / or the total flow of the external circulating pump set to realize the balance of the internal and external circulating flows on the two sides of the open water tank; on the basis that the first priority control target is met, second priority adjustment is carried out on the operation load of the salt water ice machine based on the preset multiple judgment rules, and supply and demand balance of the system cooling capacity is achieved, so that cooperative control over the internal and external circulation flow and the cooling capacity of the chilled water system is achieved, and then the cooling effect on materials of the reaction kettle is improved.

Description

Technical Field

[0001] This invention relates to the field of industrial refrigeration control technology, and in particular to a method and device for coordinated control of internal and external circulation in a chilled water system. Background Technology

[0002] In low-temperature reaction processes in industries such as chemical and pharmaceutical manufacturing, brine chillers are often used to produce chilled water. This chilled water is first buffered in an open-type partitioned water tank, and then pumped to the reactor jacket for heat exchange. In this typical system, the balance of water levels in the internal and external circulation on both sides of the open water tank baffle is a core element for stable system operation: when the external circulation flow rate is consistently greater than the internal circulation flow rate, the water level in the low-temperature zone will drop, potentially leading to cavitation; conversely, when the internal circulation flow rate is greater than the external circulation flow rate, the water level in the high-temperature zone will rise, risking overflow. Any imbalance in water levels will directly disrupt the system's original temperature gradient, potentially causing a significant increase in chiller energy consumption or even process cooling failure. Simultaneously, cooling capacity control is also crucial, as it directly affects the cooling effect of the chilled water system. Summary of the Invention

[0003] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method and device for coordinated control of internal and external circulation of chilled water system, which solves the technical problem of coordinated control of internal and external circulation flow and cooling capacity.

[0004] To achieve the above objectives, the main technical solutions adopted by the present invention include: The first aspect of this invention provides a method for coordinated control of internal and external circulation in a chilled water system.

[0005] The chilled water system internal and external circulation coordinated control method proposed in this embodiment of the invention includes at least one brine chiller, an open water tank divided into a high-temperature zone and a low-temperature zone by a baffle, an internal circulation pump group connected to the brine chiller in a one-to-one correspondence, and an external circulation pump group connected to the end of the process; the method includes: The water levels in the high-temperature zone and the low-temperature zone of the open water tank are collected in real time, and the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is determined based on the water levels in the high-temperature zone and the low-temperature zone of the open water tank. With controlling the water level difference within a set threshold range as the first priority control objective, the internal and external circulation flow balance on both sides of the open water tank is achieved by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group. Based on meeting the first priority control objective, and based on preset multiple judgment rules, the operating load of the brine chiller is adjusted with a second priority to achieve a balance between the supply and demand of cooling capacity in the system. The multiple judgment rules are judgment rules for determining whether to perform brine chiller operating load adjustment based on the main pipe water supply temperature, load rate, and the difference between internal and external circulation flow rates.

[0006] In some instances, the multiple judgment rules include a load reduction triple judgment rule and a load increase triple judgment rule; Based on satisfying the first priority control objective, and according to preset multiple judgment rules, the operating load of the brine ice machine is adjusted with a second priority to achieve a balance between the supply and demand of the system's cooling capacity, including: Based on meeting the first priority control objective, and according to the aforementioned triple load reduction judgment rule, the operating load of the brine ice machine is reduced to achieve a balance between the supply and demand of system cooling capacity; or, Based on meeting the first priority control objective, and according to the triple judgment rule for loading, the operating load of the brine ice machine is loaded to achieve a balance between the supply and demand of cooling capacity in the system.

[0007] In some instances, the step of reducing the operating load of the brine ice machine based on the triple load reduction judgment rule, while satisfying the first priority control objective, to achieve a balance between the supply and demand of system cooling capacity, includes: Determine whether the main water supply temperature of the external circulation pump set is lower than the preset reduction water temperature setting value; If the main water supply temperature of the external circulation pump set is lower than the preset reduction water temperature setting value, it is determined whether there is a brine ice machine currently in operation that is not in full-load operation. If a running brine ice machine is not operating at full load, then determine whether the difference between the total flow rate of the internal circulation pump group and the total flow rate of the external circulation pump group is greater than or equal to the preset reduction flow rate setting value. If the difference between the total flow rate of the internal circulation pump group and the total flow rate of the external circulation pump group is greater than or equal to the preset reduction flow rate setting value, then the operating load of the brine ice machine will be reduced.

[0008] In some instances, the step of loading the brine ice machine based on the triple-judgment rule, while satisfying the first priority control objective, to achieve a balance between the supply and demand of the system's cooling capacity, includes: Determine whether the main water supply temperature of the external circulation pump set is higher than the preset machine water temperature setting value; If the main pipe water supply temperature of the external circulation pump set is higher than the preset machine water temperature setting value, then it is determined whether the operating load of all working brine ice machines is higher than the first load threshold. If the operating load of all working brine ice machines is higher than the first load threshold, then determine whether the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset machine flow rate setting value. If the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset machine loading flow rate setting value, and there is a brine ice machine in a standby state, then the operating load of the brine ice machine will be loaded.

[0009] In some instances, the primary control objective is to control the water level difference within a set threshold range. This is achieved by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group to balance the internal and external circulation flow rates on both sides of the open water tank. This includes: If the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is greater than the positive allowable value, it is determined that the water level in the high-temperature zone is too high, and it is adjusted by increasing the total flow rate of the internal circulation pump group and / or decreasing the total flow rate of the external circulation pump group. If the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is less than the negative allowable value, it is determined that the water level in the low-temperature zone is too high, and the adjustment is made by reducing the total flow rate of the internal circulation pump group and / or increasing the total flow rate of the external circulation pump group.

[0010] In some instances, after achieving a balance between the supply and demand of cooling capacity in the system, the method includes: Obtain the return water temperature at the end of the process; If the return water temperature at the end of the process is higher than the sum of the upper limit of the set value and the positive dead zone value, then the total flow rate of the internal circulation pump group is increased. If the return water temperature at the end of the process is lower than the sum of the set lower limit and the negative dead zone value, then the total flow rate of the internal circulation pump group shall be reduced.

[0011] In some instances, after achieving a balance between the supply and demand of cooling capacity in the system, the method includes: A power consumption model is established for each pump in the external circulation pump group. The power consumption model represents the functional relationship between the pump's operating power consumption and its operating frequency. Based on meeting the total flow requirements and water supply pressure constraints of the external circulation pump set, optimization calculations are performed with the goal of minimizing the total operating power consumption of the external circulation pump set, and optimization results are obtained. Based on the optimization results, control commands are output for the start / stop status and / or operating frequency of each external circulation pump.

[0012] A second aspect of this invention provides a coordinated control device for internal and external circulation of a chilled water system, comprising at least one brine chiller, an open water tank divided into a high-temperature zone and a low-temperature zone by a baffle, an internal circulation pump group connected to each of the brine chillers, and an external circulation pump group connected to the end of the process; the device includes: The data acquisition unit is used to collect the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank in real time, and to determine the water level difference between the high-temperature zone and the low-temperature zone of the open water tank based on the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank. The flow regulation unit is used to achieve the balance of internal and external circulation flow on both sides of the open water tank by dynamically adjusting the total flow of the internal circulation pump group and / or the total flow of the external circulation pump group, with the first priority control target being to control the water level difference within a set threshold range. The load adjustment unit is used to adjust the operating load of the brine chiller in a second priority manner based on preset multiple judgment rules, on the basis of satisfying the first priority control target, so as to achieve a balance between the supply and demand of the system's cooling capacity; wherein, the multiple judgment rules are judgment rules for whether to perform brine chiller operating load adjustment based on the main pipe water supply temperature, load rate and the difference between internal and external circulation flow rates as judgment factors.

[0013] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the steps of the method described in the first aspect above.

[0014] A fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the program to implement the steps of the method described in the first aspect above.

[0015] The present invention discloses a method for coordinated control of internal and external circulation in a chilled water system, comprising: at least one brine chiller, an open water tank divided into a high-temperature zone and a low-temperature zone by a baffle, an internal circulation pump group connected to the brine chiller in a one-to-one correspondence, and an external circulation pump group connected to the end of the process; the method comprises: real-time acquisition of the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank, and determining the water level difference between the high-temperature zone and the low-temperature zone of the open water tank based on the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank; taking controlling the water level difference within a set threshold range as the first priority control objective, achieving a balance of internal and external circulation flow on both sides of the open water tank by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group; based on satisfying the first priority control objective, adjusting the operating load of the brine chiller according to a second priority based on preset multiple judgment rules to achieve a balance between the supply and demand of cooling capacity in the system; wherein, the multiple judgment rules are judgment rules for determining whether to perform brine chiller operating load adjustment based on the main pipe supply water temperature, load rate, and the difference between internal and external circulation flow rates as judgment factors. In this application, based on the balance of internal and external circulation flow on both sides of the water tank, the operating load of the brine chiller is adjusted with a second priority through multiple judgment rules to achieve a balance between the supply and demand of the system's cooling capacity. This is conducive to the coordinated control of the internal and external circulation flow and cooling capacity of the chilled water system, and thus helps to improve the cooling effect on the materials in the reactor. Attached Figure Description

[0016] Figure 1 A flowchart of a method for coordinated control of internal and external circulation in a chilled water system provided in an embodiment of the present invention; Figure 2 A structural diagram of a chilled water system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the overall architecture of a chilled water system internal and external circulation coordinated control system provided in an embodiment of the present invention; Figure 4 A flowchart of a chilled water system internal and external circulation coordinated control refrigeration unit unloading and shutdown process provided in an embodiment of the present invention; Figure 5 A flowchart of the loading and startup process of a chilled water system internal and external circulation coordinated control refrigeration unit is provided for an embodiment of the present invention; Figure 6 This is a schematic diagram of a chilled water system internal and external circulation coordinated control device provided in an embodiment of the present invention. Detailed Implementation

[0017] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The chilled water system internal and external circulation coordinated control method proposed in this invention is used to solve the problem of coordinated control of internal and external circulation flow and cooling capacity in chilled water systems. Based on the balance of internal and external circulation flow on both sides of the water tank, the operating load of the brine chiller is adjusted with a second priority through multiple judgment rules to achieve a balance between supply and demand of cooling capacity in the system. This is conducive to achieving coordinated control of internal and external circulation flow and cooling capacity in chilled water systems, and thus helps to improve the cooling effect on materials in the reactor.

[0019] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0020] Figure 1 This is a flowchart illustrating a method for coordinated control of internal and external circulation in a chilled water system, as provided in an embodiment of the present invention. Figure 1 As shown in the embodiment of the present invention, the method for coordinated control of internal and external circulation in a chilled water system includes at least one brine chiller, an open water tank divided into a high-temperature zone and a low-temperature zone by a baffle, an internal circulation pump group connected to the brine chiller in a one-to-one correspondence, and an external circulation pump group connected to the end of the process; the method includes: Step 100: Collect the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank in real time, and determine the water level difference between the high-temperature zone and the low-temperature zone of the open water tank based on the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank. Step 110: Taking controlling the water level difference within a set threshold range as the first priority control objective, the internal and external circulation flow balance on both sides of the open water tank is achieved by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group. Step 120: Based on satisfying the first priority control objective, the operating load of the brine chiller is adjusted to a second priority according to a preset multi-judgment rule to achieve a balance between the supply and demand of the system's cooling capacity; wherein, the multi-judgment rule is a judgment rule for whether to perform brine chiller operating load adjustment based on the main pipe water supply temperature, load rate and the difference between internal and external circulation flow rates as judgment factors.

[0021] In this exemplary embodiment, the brine chiller uses calcium chloride solution as a refrigerant and is capable of outputting chilled water at a temperature of -15°C. The open-type water tank has internal baffles that divide it into a high-temperature zone and a low-temperature zone. The high-temperature zone receives process return water, while the low-temperature zone stores the chilled water produced by the chiller. Overflow from the baffle's top outlet creates a temperature gradient between the two zones. The internal circulation pump pumps chilled water produced by the ice machine into the low-temperature zone of the water tank, while simultaneously drawing high-temperature process return water from the high-temperature zone and sending it into the ice machine. The external circulation pump draws chilled water from the low-temperature zone to provide cooling for the reactor, while simultaneously sending high-temperature process return water into the high-temperature zone of the water tank. After the chilled water absorbs and carries away the heat generated during the reaction in the reactor jacket, its own temperature will rise, and it will eventually return to the high-temperature zone of the water tank as return water.

[0022] Figure 2 This is a structural diagram of a chilled water system provided in an embodiment of the present invention. Figure 2 As shown, multiple brine chillers deliver the produced chilled water to the low-temperature zone of an open water tank. An internal circulation pump returns water from the high-temperature zone of the tank to the brine chiller; each internal circulation pump corresponds to one of the main units, forming a refrigeration unit. An external circulation pump draws chilled water from the low-temperature zone and delivers it to the final reaction vessel, while the return water from the reaction vessel flows into the high-temperature zone of the water tank. The low-temperature and high-temperature zones of the water tank are separated by baffles with an opening in the center to allow for overflow from both sides.

[0023] In this application, based on the balance of internal and external circulation flow on both sides of the water tank, the operating load of the brine chiller is adjusted with a second priority through multiple judgment rules to achieve a balance between the supply and demand of the system's cooling capacity. This is conducive to the coordinated control of the internal and external circulation flow and cooling capacity of the chilled water system, and thus helps to improve the cooling effect on the materials in the reactor.

[0024] In some instances, the multiple judgment rules include a load reduction triple judgment rule and a load increase triple judgment rule; Based on satisfying the first priority control objective, and according to preset multiple judgment rules, the operating load of the brine ice machine is adjusted with a second priority to achieve a balance between the supply and demand of the system's cooling capacity, including: Based on meeting the first priority control objective, and according to the aforementioned triple load reduction judgment rule, the operating load of the brine ice machine is reduced to achieve a balance between the supply and demand of system cooling capacity; or, Based on meeting the first priority control objective, and according to the triple judgment rule for loading, the operating load of the brine ice machine is loaded to achieve a balance between the supply and demand of cooling capacity in the system.

[0025] In this exemplary embodiment, based on satisfying the first priority control objective, and based on the triple load reduction judgment rule, the operating load of the brine ice machine is reduced to achieve a balance between the supply and demand of system cooling capacity; and Based on meeting the first priority control objective, and according to the aforementioned triple-judgment rule for loading, the operating load of the brine ice machine is adjusted to achieve a balance between the supply and demand of cooling capacity in the system. This facilitates corresponding operating load management operations under different conditions, thereby improving the effectiveness of coordinated control.

[0026] In some instances, the step of reducing the operating load of the brine ice machine based on the triple load reduction judgment rule, while satisfying the first priority control objective, to achieve a balance between the supply and demand of system cooling capacity, includes: Determine whether the main water supply temperature of the external circulation pump set is lower than the preset reduction water temperature setting value; If the main water supply temperature of the external circulation pump set is lower than the preset reduction water temperature setting value, it is determined whether there is a brine ice machine currently in operation that is not in full-load operation. If a running brine ice machine is not operating at full load, then determine whether the difference between the total flow rate of the internal circulation pump group and the total flow rate of the external circulation pump group is greater than or equal to the preset reduction flow rate setting value. If the difference between the total flow rate of the internal circulation pump group and the total flow rate of the external circulation pump group is greater than or equal to the preset reduction flow rate setting value, then the operating load of the brine ice machine will be reduced.

[0027] In this exemplary embodiment, if the main water supply temperature of the external circulation pump group is lower than the preset cooling water temperature setting, it indicates that the cooling effect of the chilled water system is relatively ideal, and a load reduction operation can be performed, indicating a need for load reduction. If any operating brine chillers are not operating at full load, it means that not all brine chillers are working at full load. At this time, multiple brine chillers may be operating at low load. Given the need for load reduction, a brine chiller load reduction operation can be performed to shut down some refrigeration units, thereby improving the overall efficiency of the chilled water system and reducing resource consumption.

[0028] If the difference between the total flow rate of the internal circulation pump set and the total flow rate of the external circulation pump set is greater than or equal to the preset reduction flow rate setting value, it indicates that the cooling capacity supplied is greater than the cooling capacity required, and it also indicates that the chilled water system needs to reduce its load at this time.

[0029] In some instances, the step of loading the brine ice machine based on the triple-judgment rule, while satisfying the first priority control objective, to achieve a balance between the supply and demand of the system's cooling capacity, includes: Determine whether the main water supply temperature of the external circulation pump set is higher than the preset machine water temperature setting value; If the main pipe water supply temperature of the external circulation pump set is higher than the preset machine water temperature setting value, then it is determined whether the operating load of all working brine ice machines is higher than the first load threshold. If the operating load of all working brine ice machines is higher than the first load threshold, then determine whether the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset machine flow rate setting value. If the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset machine loading flow rate setting value, and there is a brine ice machine in a standby state, then the operating load of the brine ice machine will be loaded.

[0030] In this exemplary embodiment, if the main water supply temperature of the external circulation pump group is higher than the preset set value for the added chilled water temperature, it indicates that the cooling effect of the chilled water system is not ideal, and a loading operation can be performed, indicating a need for loading. If the operating load of all working brine chillers is higher than the first load threshold (the first load threshold can be set as needed, for example, 80%), it indicates that all chillers are already operating at high load. At this time, there is a need to increase the operation of brine chillers, so a brine chiller loading operation can be performed to add some refrigeration units, thereby improving the overall working efficiency of the chilled water system.

[0031] If the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset additional flow rate setting value, it indicates that the cooling demand is greater than the cooling supply, and that the chilled water system needs to be loaded at this time.

[0032] In some instances, the primary control objective is to control the water level difference within a set threshold range. This is achieved by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group to balance the internal and external circulation flow rates on both sides of the open water tank. This includes: If the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is greater than the positive allowable value, it is determined that the water level in the high-temperature zone is too high, and it is adjusted by increasing the total flow rate of the internal circulation pump group and / or decreasing the total flow rate of the external circulation pump group. If the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is less than the negative allowable value, it is determined that the water level in the low-temperature zone is too high, and the adjustment is made by reducing the total flow rate of the internal circulation pump group and / or increasing the total flow rate of the external circulation pump group.

[0033] In this exemplary embodiment, the water level is the result of the accumulated flow and is the most direct and stable indicator of whether the internal and external flow is balanced. Therefore, the water level difference Lh-Ll is used as the main feedback signal.

[0034] If Lh-Ll > the set allowable water level difference △Lset, meaning the water level in the high-temperature zone is high, it indicates that the total external circulation flow rate is greater than the total internal circulation flow rate. In this case, the internal circulation pump flow rate can be increased or the total external circulation pump flow rate can be decreased. During the adjustment of the external circulation pump, it is necessary to ensure that the pressure of the main external circulation water supply pipe meets the process requirements.

[0035] If Ll-Lh>△Lset, meaning the water level in the low-temperature zone is high, it indicates that the total external circulation flow rate is less than the total internal circulation flow rate. In this case, the internal circulation pump flow rate can be reduced or the total external circulation pump flow rate can be increased. During the adjustment of the internal circulation pump flow rate, it is necessary to ensure that the flow rate of a single internal circulation pump is greater than or equal to the minimum evaporator flow rate of the corresponding ice machine to meet the normal operating conditions of the ice machine.

[0036] In some instances, after achieving a balance between the supply and demand of cooling capacity in the system, the method includes: Obtain the return water temperature at the end of the process; If the return water temperature at the end of the process is higher than the sum of the upper limit of the set value and the positive dead zone value, then the total flow rate of the internal circulation pump group is increased. If the return water temperature at the end of the process is lower than the sum of the set lower limit and the negative dead zone value, then the total flow rate of the internal circulation pump group shall be reduced.

[0037] In this exemplary embodiment, Maintain the temperature of the high-temperature zone in the water tank near the upper limit of the set value. If the temperature of the high-temperature zone in the water tank is too high, it indicates insufficient cooling capacity (insufficient ice machine capacity or insufficient internal circulation flow) or excessive external circulation; if the temperature of the high-temperature zone in the water tank is too low, the opposite is true.

[0038] Maintain the temperature of the water tank's low-temperature zone near the lower limit of the set value. If the temperature of the water tank's low-temperature zone is too low, it indicates excessive cooling capacity (excessive ice machine capacity); conversely, if the temperature of the water tank's low-temperature zone is too high, it indicates the opposite.

[0039] The key process return water temperature, ensuring it is less than or equal to the required process temperature, is the fundamental purpose of the system. This is achieved by adjusting the total external circulation flow rate and the ice machine output.

[0040] If the return water temperature at the end of the process is greater than the sum of the upper limit of the set value and the positive dead zone value, it means that the current cooling capacity cannot meet the cooling demand of the end users. In this case, the frequency of the internal circulation pump should be increased first to increase the output of the ice machine. If the return water temperature at the end of the process is less than the sum of the set lower limit and the negative dead zone value, it indicates that the current low temperature zone is too cold. The frequency of the internal circulation pump should be reduced first to reduce the output of the ice machine. The flow rate of the internal circulation pump has reached the minimum flow rate limit of the ice machine evaporator.

[0041] In some instances, after achieving a balance between the supply and demand of cooling capacity in the system, the method includes: A power consumption model is established for each pump in the external circulation pump group. The power consumption model represents the functional relationship between the pump's operating power consumption and its operating frequency. Based on meeting the total flow requirements and water supply pressure constraints of the external circulation pump set, optimization calculations are performed with the goal of minimizing the total operating power consumption of the external circulation pump set, and optimization results are obtained. Based on the optimization results, control commands are output for the start / stop status and / or operating frequency of each external circulation pump.

[0042] In this exemplary embodiment, the external circulation pump set consists of multiple variable frequency pumps of the same model connected in parallel. During flow regulation, the coordinated optimization of the external circulation pump set needs to be considered, requiring the establishment of a power consumption model for the pumps to accurately calculate the actual operating power and energy consumption of each device. The actual operating power consumption of the circulating water pumps is as follows.

[0043] ;in, In the formula, The power consumption of the circulating water pump. and The actual and rated frequencies of the circulating water pump are given; b0, b1, b2, and b3 are fitting coefficients, which vary depending on the type of water pump.

[0044] The goal is to minimize the total power consumption of the entire external circulation pump unit while ensuring the supply of chilled water and the required cooling capacity. The objective function for minimizing the total power consumption of the external circulation pump unit is as follows: = ; Let be the power consumption of the i-th circulating pump.

[0045] Furthermore, the optimization of the circulating water system must meet the water level balance constraint, and the frequency of the variable frequency pump must be within the normal range. ; Let be the pump frequency of the i-th circulating pump. This is the lower limit of the pump frequency of the i-th circulating pump. This represents the upper limit of the pump frequency for the i-th circulating pump.

[0046] Output results: The output of the optimization results includes water pump, start / stop signals, and operating frequency.

[0047] Figure 3 This is a schematic diagram of the overall architecture of a chilled water system internal and external circulation coordinated control system provided in an embodiment of the present invention. Figure 3As shown, the brine chiller and internal circulation pump 30 output low-temperature chilled water to the low-temperature zone 32 of the water tank. The reactor 34 returns high-temperature water to the high-temperature zone 31 of the water tank. The low-temperature zone 32 of the water tank supplies water to the external circulation pump 33, which in turn supplies water to the reactor 34. The reactor 34 then returns the water at a flow rate F... r Return water temperature T r Water supply temperature T s and water supply pressure P s It is transmitted to the intelligent control system.

[0048] Figure 4 This invention provides a flowchart of a chilled water system internal and external circulation coordinated control refrigeration unit unloading and shutdown process according to an embodiment of the invention. Figure 4 As shown, the cooling unit's unloading and shutdown process under coordinated internal and external circulation control includes: Step 40: Read the current operating parameters of the system; Step 41: Determine whether the main water supply temperature is less than or equal to the set value of the reducer water temperature; Step 42: If the main water supply temperature is less than or equal to the chiller water temperature setting value, determine whether there is a chiller operating at less than 100% capacity. Step 43: If the operating chiller load is less than 100%, determine whether the difference between the internal circulation flow and the external circulation flow is greater than or equal to the chiller reduction setting value. Step 44: If the difference between the internal circulation flow rate and the external circulation flow rate is greater than or equal to the reduction setting value, then shut down one cooling unit with the lowest load.

[0049] Figure 5 This invention provides a flowchart for the loading and startup of a refrigeration unit under coordinated internal and external circulation control in a chilled water system, as part of an embodiment of the present invention. Figure 5 As shown, the chilled water system's internal and external circulation coordinated control refrigeration unit loading and startup process includes: Step 50: Read the current operating parameters of the system; Step 51: Determine whether the main water supply temperature is greater than or equal to the set value of the machine water temperature; Step 52: If the main water supply temperature is greater than or equal to the set value of the chiller water temperature, determine whether the load of all operating chillers is greater than 85%. Step 53: If the load of all operating chillers is greater than 85%, then determine whether the difference between the external circulation flow rate and the internal circulation flow rate is greater than or equal to the set value of the chiller. Step 54: If the difference between the internal circulation flow rate and the external circulation flow rate is greater than or equal to the set value for the chiller, then determine if there are any unused chiller units with a load value of 0. Step 55: If there are unused chiller units with a load factor of 0, then add a chiller unit with the shortest cumulative operating time.

[0050] This invention provides a coordinated control device for internal and external circulation of a chilled water system, comprising at least one brine chiller, an open water tank divided into a high-temperature zone and a low-temperature zone by a baffle, an internal circulation pump group connected to the brine chiller in a one-to-one correspondence, and an external circulation pump group connected to the end of the process. Figure 6 This is a schematic diagram of a chilled water system internal and external circulation coordinated control device provided in an embodiment of the present invention. Figure 6 As shown, the device includes: The data acquisition unit 60 is used to collect the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank in real time, and to determine the water level difference between the high-temperature zone and the low-temperature zone of the open water tank based on the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank. The flow regulation unit 61 is used to achieve the balance of internal and external circulation flow on both sides of the open water tank by dynamically adjusting the total flow of the internal circulation pump group and / or the total flow of the external circulation pump group, with the first priority control target being to control the water level difference within a set threshold range. The load adjustment unit 62 is used to adjust the operating load of the brine chiller in a second priority manner based on preset multiple judgment rules, on the basis of satisfying the first priority control target, so as to achieve a balance between the supply and demand of the system's cooling capacity; wherein, the multiple judgment rules are judgment rules for whether to perform brine chiller operating load adjustment based on the main pipe water supply temperature, load rate and the difference between internal and external circulation flow rates as judgment factors.

[0051] In this exemplary embodiment, the brine chiller uses calcium chloride solution as a refrigerant and is capable of outputting chilled water at a temperature of -15°C. The open-type water tank has internal baffles that divide it into a high-temperature zone and a low-temperature zone. The high-temperature zone receives process return water, while the low-temperature zone stores the chilled water produced by the chiller. Overflow from the baffle's top outlet creates a temperature gradient between the two zones. The internal circulation pump pumps chilled water produced by the ice machine into the low-temperature zone of the water tank, while simultaneously drawing high-temperature process return water from the high-temperature zone and sending it into the ice machine. The external circulation pump draws chilled water from the low-temperature zone to provide cooling for the reactor, while simultaneously sending high-temperature process return water into the high-temperature zone of the water tank. After the chilled water absorbs and carries away the heat generated during the reaction in the reactor jacket, its own temperature will rise, and it will eventually return to the high-temperature zone of the water tank as return water.

[0052] like Figure 2As shown, multiple brine chillers deliver the produced chilled water to the low-temperature zone of an open water tank. An internal circulation pump returns water from the high-temperature zone of the tank to the brine chiller; each internal circulation pump corresponds to one of the main units, forming a refrigeration unit. An external circulation pump draws chilled water from the low-temperature zone and delivers it to the final reaction vessel, while the return water from the reaction vessel flows into the high-temperature zone of the water tank. The low-temperature and high-temperature zones of the water tank are separated by baffles with an opening in the center to allow for overflow from both sides.

[0053] In this application, based on the balance of internal and external circulation flow on both sides of the water tank, the operating load of the brine chiller is adjusted with a second priority through multiple judgment rules to achieve a balance between the supply and demand of the system's cooling capacity. This is conducive to the coordinated control of the internal and external circulation flow and cooling capacity of the chilled water system, and thus helps to improve the cooling effect on the materials in the reactor.

[0054] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be repeated here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0055] This invention provides a computer-readable storage medium, characterized in that it stores a chilled water system internal and external circulation coordinated control program thereon. When the chilled water system internal and external circulation coordinated control program is executed by a processor, it implements the chilled water system internal and external circulation coordinated control method described in the above embodiments.

[0056] This invention provides an electronic device, characterized in that it includes a memory, a processor, and a chilled water system internal and external circulation coordinated control program stored in the memory and executable on the processor. When the processor executes the chilled water system internal and external circulation coordinated control program, it implements the chilled water system internal and external circulation coordinated control method described in the above embodiments.

[0057] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0060] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for coordinated control of internal and external circulation in a chilled water system, characterized in that, The method comprises at least one brine ice machine, an open water tank divided into a high-temperature zone and a low-temperature zone by baffles, an internal circulation pump group connected to the brine ice machine in a one-to-one correspondence, and an external circulation pump group connected to the end of the process; the method includes: The water levels in the high-temperature zone and the low-temperature zone of the open water tank are collected in real time, and the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is determined based on the water levels in the high-temperature zone and the low-temperature zone of the open water tank. With controlling the water level difference within a set threshold range as the first priority control objective, the internal and external circulation flow balance on both sides of the open water tank is achieved by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group. Based on meeting the first priority control objective, and based on preset multiple judgment rules, the operating load of the brine chiller is adjusted with a second priority to achieve a balance between the supply and demand of cooling capacity in the system. The multiple judgment rules are judgment rules for determining whether to perform brine chiller operating load adjustment based on the main pipe water supply temperature, load rate, and the difference between internal and external circulation flow rates.

2. The method for coordinated control of internal and external circulation in a chilled water system according to claim 1, characterized in that, The multiple judgment rules include a three-fold judgment rule for load reduction and a three-fold judgment rule for load loading; Based on satisfying the first priority control objective, and according to preset multiple judgment rules, the operating load of the brine ice machine is adjusted with a second priority to achieve a balance between the supply and demand of the system's cooling capacity, including: Based on meeting the first priority control objective, and according to the aforementioned triple load reduction judgment rule, the operating load of the brine ice machine is reduced to achieve a balance between the supply and demand of system cooling capacity; or, Based on meeting the first priority control objective, and according to the triple judgment rule for loading, the operating load of the brine ice machine is loaded to achieve a balance between the supply and demand of cooling capacity in the system.

3. The method for coordinated control of internal and external circulation in a chilled water system according to claim 2, characterized in that, Based on satisfying the first priority control objective, and according to the triple load reduction judgment rule, the operating load of the brine ice machine is reduced to achieve a balance between the supply and demand of system cooling capacity, including: Determine whether the main water supply temperature of the external circulation pump set is lower than the preset reduction water temperature setting value; If the main water supply temperature of the external circulation pump set is lower than the preset reduction water temperature setting value, it is determined whether there is a brine ice machine currently in operation that is not in full-load operation. If a running brine ice machine is not operating at full load, then determine whether the difference between the total flow rate of the internal circulation pump group and the total flow rate of the external circulation pump group is greater than or equal to the preset reduction flow rate setting value. If the difference between the total flow rate of the internal circulation pump group and the total flow rate of the external circulation pump group is greater than or equal to the preset reduction flow rate setting value, then the operating load of the brine ice machine will be reduced.

4. The method for coordinated control of internal and external circulation in a chilled water system according to claim 2, characterized in that, Based on satisfying the first priority control objective, and according to the triple loading judgment rule, the operating load of the brine ice machine is loaded to achieve a balance between the supply and demand of the system's cooling capacity, including: Determine whether the main water supply temperature of the external circulation pump set is higher than the preset machine water temperature setting value; If the main pipe water supply temperature of the external circulation pump set is higher than the preset machine water temperature setting value, then it is determined whether the operating load of all working brine ice machines is higher than the first load threshold. If the operating load of all working brine ice machines is higher than the first load threshold, then determine whether the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset machine flow rate setting value. If the difference between the total flow rate of the external circulation pump group and the total flow rate of the internal circulation pump group is greater than or equal to the preset machine loading flow rate setting value, and there is a brine ice machine in a standby state, then the operating load of the brine ice machine will be loaded.

5. The method for coordinated control of internal and external circulation in a chilled water system according to claim 1, characterized in that, The first priority control objective is to control the water level difference within a set threshold range. This is achieved by dynamically adjusting the total flow rate of the internal circulation pump group and / or the total flow rate of the external circulation pump group to balance the internal and external circulation flow rates on both sides of the open water tank. This includes: If the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is greater than the positive allowable value, it is determined that the water level in the high-temperature zone is too high, and it is adjusted by increasing the total flow rate of the internal circulation pump group and / or decreasing the total flow rate of the external circulation pump group. If the water level difference between the high-temperature zone and the low-temperature zone of the open water tank is less than the negative allowable value, it is determined that the water level in the low-temperature zone is too high, and the adjustment is made by reducing the total flow rate of the internal circulation pump group and / or increasing the total flow rate of the external circulation pump group.

6. The method for coordinated control of internal and external circulation in a chilled water system according to claim 1, characterized in that, After achieving a balance between the supply and demand of cooling capacity in the system, the method includes: Obtain the return water temperature at the end of the process; If the return water temperature at the end of the process is higher than the sum of the upper limit of the set value and the positive dead zone value, then the total flow rate of the internal circulation pump group is increased. If the return water temperature at the end of the process is lower than the sum of the set lower limit and the negative dead zone value, then the total flow rate of the internal circulation pump group shall be reduced.

7. The method for coordinated control of internal and external circulation in a chilled water system according to claim 1, characterized in that, After achieving a balance between the supply and demand of cooling capacity in the system, the method includes: A power consumption model is established for each pump in the external circulation pump group. The power consumption model represents the functional relationship between the pump's operating power consumption and its operating frequency. Based on meeting the total flow requirements and water supply pressure constraints of the external circulation pump set, optimization calculations are performed with the goal of minimizing the total operating power consumption of the external circulation pump set, and optimization results are obtained. Based on the optimization results, control commands are output for the start / stop status and / or operating frequency of each external circulation pump.

8. A coordinated control device for internal and external circulation of a chilled water system, characterized in that, The device comprises at least one brine ice machine, an open water tank divided into a high-temperature zone and a low-temperature zone by a baffle, an internal circulation pump set connected to the brine ice machine in a one-to-one correspondence, and an external circulation pump set connected to the end of the process; the device includes: The data acquisition unit is used to collect the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank in real time, and to determine the water level difference between the high-temperature zone and the low-temperature zone of the open water tank based on the water level in the high-temperature zone and the water level in the low-temperature zone of the open water tank. The flow regulation unit is used to achieve the balance of internal and external circulation flow on both sides of the open water tank by dynamically adjusting the total flow of the internal circulation pump group and / or the total flow of the external circulation pump group, with the first priority control target being to control the water level difference within a set threshold range. The load adjustment unit is used to adjust the operating load of the brine chiller in a second priority manner based on preset multiple judgment rules, on the basis of satisfying the first priority control target, so as to achieve a balance between the supply and demand of the system's cooling capacity; wherein, the multiple judgment rules are judgment rules for whether to perform brine chiller operating load adjustment based on the main pipe water supply temperature, load rate and the difference between internal and external circulation flow rates as judgment factors.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 7.

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