An evaporative condenser water chilling unit adaptive load regulation and energy saving control method

Abstract

The application discloses a kind of evaporative condensing cold water unit self-adapting load regulation and energy-saving control method, obtains the cold load state of unit, environment heat exchange state and operating state, establishes working condition reference state under stable condition and determines reference comprehensive energy consumption;Condensing fan and / or spray operating parameter regulation are implemented, determine the working condition disturbance according to the change of cold load and environment heat exchange state before and after control action, and determine the reference energy consumption change caused by working condition disturbance;Subtract reference energy consumption change from actual energy consumption change, obtain the net energy consumption response and energy-saving contribution corresponding to control action;According to energy-saving contribution, adjust adjustment object, direction and step length, form candidate operating point and determine low comprehensive energy consumption operating point under the condition of satisfying unit operating constraint;When working condition changes obviously, re-establish working condition reference state and execute energy-saving regulation.

Description

Technical Field

[0001] This invention relates to the field of energy-saving control technology for chiller units, specifically to an adaptive load regulation and energy-saving control method for evaporative condensing chiller units. Background Technology

[0002] Evaporative condensing chillers enhance condensation heat exchange through airflow and spray water evaporation. They are typically equipped with a compressor, condenser fan, spray circulation pump, and corresponding monitoring and control components. Current energy-saving control methods generally adjust condenser fan speed and spray water flow rate based on parameters such as condensing pressure, chilled water temperature, unit load, or real-time energy efficiency, and judge the adjustment effect by analyzing the changes in power or energy efficiency before and after the adjustment. Under relatively stable load and environmental conditions, this method can improve unit operating efficiency to a certain extent.

[0003] However, in actual operation, the terminal cooling load, ambient wet-bulb temperature, and air humidity continuously change, simultaneously affecting the compressor load, condenser heat dissipation demand, and the heat exchange status of the evaporative condenser. Existing technologies still have the following problems:

[0004] 1. The sources of energy consumption changes are difficult to distinguish. During the implementation of control actions, the cooling load and environmental heat exchange conditions may change simultaneously, so that the actual overall energy consumption change includes the effects of both control actions and operating condition disturbances.

[0005] 2. The actual energy-saving contribution of control actions is difficult to accurately identify. A decrease in load or an improvement in environmental conditions may naturally lead to a reduction in overall energy consumption. If the power or energy efficiency is directly compared before and after control, it is easy to misjudge the energy consumption reduction caused by changes in operating conditions as the energy-saving effect produced by control actions.

[0006] 3. Misjudgment of energy-saving contribution further affects the direction of adjustment. When the energy-saving effect of control actions is misjudged, ineffective adjustment may continue to expand or the direction of effective adjustment may be changed prematurely, causing repeated adjustments to fan and spray parameters, making it difficult to stably approach the low overall energy consumption operating range.

[0007] 4. Existing energy-saving operating points are difficult to adapt to changes in operating conditions. When the cooling load or environmental heat exchange conditions change significantly, the energy-saving evaluation benchmarks and operating parameters determined under the original operating conditions may no longer be applicable, affecting the stability and adaptability of energy-saving control under dynamic operating conditions.

[0008] In view of this, the present invention provides an adaptive load regulation and energy-saving control method for evaporative condensing chillers to solve the above problems. Summary of the Invention

[0009] The purpose of this invention is to provide an adaptive load regulation and energy-saving control method for evaporative condensing chillers, which solves the problems of dynamic load and environmental changes interfering with the energy consumption evaluation of the unit, making it difficult to accurately identify the energy-saving contribution of control actions, easily misjudging the direction of adjustment, and making it difficult to stably track the low-energy-consumption operating point.

[0010] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides an adaptive load regulation and energy-saving control method for evaporative condensing chillers, comprising the following steps:

[0011] The cooling load status, ambient heat exchange status, and unit operating status of the evaporative condensing chiller are obtained. When the control parameters remain unchanged and the cooling load status and ambient heat exchange status meet the stability conditions, a reference operating status is established, and the reference comprehensive energy consumption is determined.

[0012] Adjust at least one of the condenser fan operating parameters and spray operating parameters according to the current control parameters, and obtain the cooling load status, environmental heat exchange status, unit operating status and actual comprehensive energy consumption after the control action;

[0013] The operating condition disturbance is determined based on the changes in cooling load and environmental heat exchange state before and after the control action. The operating condition disturbance is then input into the response relationship corresponding to the operating condition reference state to determine the baseline energy consumption change caused by the operating condition disturbance under the condition that the control parameters remain unchanged.

[0014] Determine the actual energy consumption change relative to the reference energy consumption, subtract the reference energy consumption change from the actual energy consumption change to obtain the net energy consumption response corresponding to the current control action, and determine the energy saving contribution of the current control action based on the net energy consumption response.

[0015] The adjustment object, adjustment direction and adjustment step size are determined according to the energy saving contribution corresponding to the condenser fan operation parameters and the spray operation parameters. Candidate operating points are generated and the unit operation constraints are verified on the candidate operating points.

[0016] Among the candidate operating points that satisfy the unit operating constraints, the adjustment direction and adjustment step size are adjusted according to the energy saving contribution corresponding to the continuous control action until the preset convergence condition is met. The candidate operating point that satisfies the unit operating constraints and has the lowest comprehensive energy consumption is determined as the current low comprehensive energy consumption operating point, and the evaporative condensing chiller is controlled to operate according to the current low comprehensive energy consumption operating point.

[0017] Furthermore, the cooling load status is determined based on the chilled water supply temperature, chilled water return temperature, and chilled water flow rate; the environmental heat exchange status includes at least two of the environmental dry-bulb temperature, environmental wet-bulb temperature, and environmental relative humidity; the unit operating status includes at least two of the compressor operating power, condenser fan operating power, spray circulation pump operating power, condensing pressure, evaporating pressure, and condenser side temperature; and the current cooling load is determined based on the chilled water flow rate and the temperature difference between the chilled water supply temperature and the chilled water return temperature.

[0018] Furthermore, establishing the aforementioned operating condition reference state includes:

[0019] During the observation period when the operating parameters of the condenser fan and the spray system remain unchanged, the cooling load status, ambient heat exchange status, and unit operating status are continuously acquired.

[0020] When the changes in cooling load and ambient heat exchange are within their respective stable ranges, the operating condition reference state is determined based on the cooling load and ambient heat exchange states during the observation period, and the reference comprehensive energy consumption corresponding to the operating condition reference state is determined based on the compressor energy consumption, condenser fan energy consumption, and spray circulation pump energy consumption.

[0021] Furthermore, the load disturbance component is determined based on the change in the current cooling load relative to the cooling load corresponding to the operating condition reference state, and the environmental heat exchange disturbance component is determined based on the changes in the ambient wet-bulb temperature and ambient relative humidity relative to the operating condition reference state. The operating condition disturbance quantity is formed based on the load disturbance component and the environmental heat exchange disturbance component. The response relationship is used to characterize the correspondence between the changes in the cooling load state and the environmental heat exchange state and the changes in the comprehensive energy consumption when the control parameters remain unchanged. The operating condition disturbance quantity is input into the response relationship to obtain the baseline energy consumption change quantity.

[0022] Furthermore, the actual overall energy consumption after the control action will be... Compared with reference comprehensive energy consumption The difference is determined as the actual change in energy consumption. : ;

[0023] The change in the baseline energy consumption is denoted as... The net energy consumption response corresponding to the current control action is determined according to the following formula. : ;

[0024] The degree to which the current control action increases or decreases the overall energy consumption relative to the baseline energy consumption corresponding to the operating condition disturbance is determined based on the direction and magnitude of the net energy consumption response, and the energy-saving contribution of the current control action is determined accordingly.

[0025] Furthermore, by changing one of the operating parameters of the condenser fan and the spray pump while keeping the other constant, the net energy consumption response of the corresponding control action is obtained. Based on each net energy consumption response and the corresponding adjustment amount of the operating parameter, the unit adjustment energy saving contribution of the condenser fan and the spray circulation pump under the current operating conditions is determined.

[0026] The energy-saving contribution per unit of adjustment is compared, and the operating parameter with the larger energy-saving contribution per unit of adjustment is adjusted first. When the energy-saving contribution per unit of adjustment corresponding to the operating parameter decreases to the preset switching condition, the adjustment object is switched.

[0027] Furthermore, if the net energy consumption response obtained after implementing control actions in the current adjustment direction indicates a reduction in overall energy consumption, the current adjustment direction should be maintained.

[0028] When the net energy consumption response indicates that the overall energy consumption has not decreased, the current adjustment direction is changed or the adjustment step size is reduced, and the adjustment direction and adjustment step size of the next control cycle are determined based on the changes in net energy consumption response corresponding to at least two consecutive control actions.

[0029] The condenser fan operating parameters include at least one of the following: fan operating frequency, number of fans in operation, or fan air volume; the spray operating parameters include at least one of the following: spray circulation pump operating frequency, number of spray circulation pumps in operation, spray water flow rate, or spray interval period.

[0030] Furthermore, the unit operating constraints include at least the chilled water supply temperature constraint, condensing pressure constraint, compressor compression ratio constraint, and evaporative condenser heat exchange state constraint.

[0031] When the operating status of any unit corresponding to a candidate operating point does not meet the corresponding unit operating constraints, the candidate operating point is canceled, and the previous candidate operating point that meets the unit operating constraints is restored. The adjustment direction of the corresponding operating parameters is changed or the adjustment step size is reduced before a new candidate operating point is generated.

[0032] Furthermore, during the continuous generation of candidate operating points that meet the unit's operating constraints, the adjustment step size is reduced when the energy-saving contribution corresponding to the continued adjustment along the current adjustment direction gradually decreases.

[0033] When the difference in comprehensive energy consumption between consecutive candidate operating points is less than the preset energy consumption change threshold and the adjustment step size reaches the preset minimum range, it is determined that the preset convergence condition is met, and the candidate operating point that meets the unit operation constraints and has the lowest comprehensive energy consumption is determined as the current low comprehensive energy consumption operating point.

[0034] Furthermore, during operation at the current low overall energy consumption operating point, the cooling load status and environmental heat exchange status are continuously acquired. When the change in the cooling load status or environmental heat exchange status relative to the corresponding status when the current low overall energy consumption operating point is determined exceeds the operating condition reconstruction conditions, the current operating condition reference status is stopped, the operating condition reference status is re-established, and energy-saving adjustment is re-executed.

[0035] The conditions for reconstructing the operating conditions include at least one of the following: the change in ambient wet-bulb temperature within a preset observation window exceeds a preset temperature threshold; the rate of change in cooling load within a preset observation window exceeds a preset load threshold; and the deviation between the actual energy consumption change and the baseline energy consumption change continuously exceeds a preset tolerance range.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] This invention establishes a reference operating condition when the cooling load and environmental heat exchange conditions are relatively stable, providing a unified energy consumption comparison benchmark for control actions. By identifying changes in cooling load and environmental heat exchange conditions during control actions and determining the expected benchmark energy consumption change caused by such disturbances, the impact of external operating condition changes on actual energy consumption changes can be separated. This avoids misjudging energy consumption reduction caused by load decreases or improved environmental heat exchange conditions as energy-saving effects from condenser fan or spray pump adjustments. Based on this, the actual energy-saving contribution of control actions is determined according to the net energy consumption response, enabling the adjustment objects, directions, and step sizes of the condenser fan and spray circulation pump to be adaptively adjusted based on the actual energy-saving effect. The low comprehensive energy consumption operating point corresponding to the current operating condition is determined through operational constraint verification and convergence judgment. When the cooling load or environmental heat exchange conditions change significantly, the reference operating condition is re-established and energy-saving optimization is performed. This reduces the interference of dynamic operating conditions on the judgment of energy-saving adjustment direction and improves the accuracy, stability, and adaptability of energy-saving control under varying load and environmental conditions. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below.

[0039] Figure 1 This is a schematic diagram of the evaporative condensing chiller unit and its control system of the present invention;

[0040] Figure 2 This is a flowchart of the adaptive load regulation and energy-saving control method for evaporative condensing chiller units of the present invention;

[0041] Figure 3 This is a schematic diagram showing the relationship between the actual energy consumption change, the baseline energy consumption change, and the net energy consumption response before and after the control action of the present invention.

[0042] Figure 4 This is a schematic diagram illustrating the process of coordinated adjustment of operating parameters of the condenser fan and the spray circulation pump, and optimization of the low overall energy consumption operating point in this invention. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention.

[0044] This invention addresses the problem that during the operation of evaporative condensing chillers, changes in terminal cooling load and environmental heat exchange conditions, along with the control actions of the condenser fan and spray circulation pump, affect the overall energy consumption of the unit. This means that the energy consumption changes before and after the control actions do not directly reflect the actual energy-saving effect of the control actions. The invention establishes a reference operating condition when the cooling load and environmental heat exchange conditions are relatively stable and determines the corresponding reference overall energy consumption. After adjusting the operating parameters of the condenser fan and / or spray circulation pump, the operating condition disturbance is determined based on the changes in cooling load and environmental heat exchange conditions before and after the control actions. The baseline energy consumption change is then determined, assuming the control parameters remain unchanged. This baseline energy consumption change is extracted from the actual energy consumption change to obtain the net energy consumption response corresponding to the current control action. The energy-saving contribution of the control action is evaluated based on this net energy consumption response, and the operating parameters of the condenser fan and spray circulation pump are adjusted accordingly. Under the condition of satisfying the unit's operating constraints, the low overall energy consumption operating point corresponding to the current operating condition is gradually determined.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment provides an evaporative condensing chiller unit, including an evaporative condensing chiller unit body, an evaporative condenser, a condensing fan, a spray circulation pump, a chilled water pump, and a controller.

[0047] The main body of an evaporative condensing chiller unit includes a compressor and a corresponding refrigerant circulation section. The refrigerant discharged from the compressor enters the evaporative condenser, and condensation and heat release are completed through air flow, spray water evaporation, and heat and mass transfer between refrigerants. After throttling and evaporative heat exchange, it returns to the compressor.

[0048] Evaporative condensers are equipped with condenser fans and spray circulation pumps. The condenser fans create airflow through the heat exchange area of ​​the evaporative condenser; the air-side heat exchange capacity is altered by changing the fan's operating frequency, number of fans in operation, or airflow rate. The spray circulation pumps supply circulating water to the heat exchange area of ​​the evaporative condenser; the water-side evaporative heat exchange capacity is altered by changing the pump's operating frequency, number of fans in operation, spray water flow rate, or spray interval.

[0049] The chilled water side is connected to the terminal load through chilled water supply pipeline and chilled water return pipeline. The terminal load can be an air conditioning terminal or a process cooling equipment. The chilled water pump is used to drive the chilled water to circulate between the evaporative condensing chiller unit and the terminal load.

[0050] A supply water temperature sensor T1, a return water temperature sensor T2, and a flow sensor F1 are installed on the chilled water side. The controller obtains the chilled water supply temperature based on the supply water temperature sensor T1, the chilled water return temperature based on the return water temperature sensor T2, and the chilled water flow rate based on the flow sensor F1.

[0051] The current cooling load is determined based on the chilled water flow rate and the temperature difference between the chilled water supply and return water. The formula is as follows:

[0052] ;

[0053] in, This indicates the current cooling load. This indicates the density of chilled water. This indicates the specific heat capacity of chilled water. Indicates chilled water flow rate, Indicates the chilled water return temperature. This indicates the temperature of the chilled water supply.

[0054] A discharge pressure sensor P1 is installed on the compressor discharge side, and a suction pressure sensor P2 is installed on the compressor suction side to obtain the condensing pressure and evaporating pressure, respectively. A spray water flow sensor F2 is installed in the spray circulation pipeline to obtain the actual spray water flow rate.

[0055] An environmental parameter sensor is installed at a corresponding location on the evaporative condenser to acquire at least two of the following: ambient dry-bulb temperature, ambient wet-bulb temperature, and ambient relative humidity. Among these, the ambient wet-bulb temperature and ambient relative humidity reflect the thermal and humidity state of the air during evaporative cooling and the evaporative heat transfer capacity, and can be used as the main parameters for determining the ambient heat transfer state.

[0056] The controller also acquires multiple unit operating parameters, including compressor operating power, condenser fan operating power, spray circulation pump operating power, condensing pressure, evaporating pressure, and condensing side temperature. Among these, the energy consumption corresponding to the compressor, condenser fan, and spray circulation pump is used to determine the unit's actual overall energy consumption.

[0057] The controller is connected to the aforementioned sensors, condenser fan, spray circulation pump, and unit control unit to acquire operating data and adjust the condenser fan operating parameters and spray operation parameters based on the subsequently determined energy-saving adjustment results.

[0058] Example 2

[0059] like Figure 2 and Figure 3 As shown, this embodiment focuses on how to separate the effects of changes in cooling load and environmental heat exchange conditions from the actual energy consumption changes of the unit under dynamic operating conditions, and determine the actual energy-saving contribution of control actions accordingly, including the following steps:

[0060] S101. Acquire unit operating data: The controller acquires the cooling load status, ambient heat exchange status, and unit operating status of the evaporative condensing chiller according to the preset sampling period.

[0061] The cooling load status is determined based on the chilled water supply temperature, chilled water return temperature, and chilled water flow rate, and the current cooling load is determined according to the method described in Example 1.

[0062] The ambient heat transfer state includes at least two of the ambient dry-bulb temperature, ambient wet-bulb temperature, and ambient relative humidity. Preferably, at least the ambient wet-bulb temperature is used to characterize the thermal and humidity state of the air surrounding the evaporative condenser, and the ambient relative humidity is used to characterize the air's ability to continue absorbing water vapor.

[0063] The unit's operating status includes multiple parameters such as compressor operating power, condenser fan operating power, spray circulation pump operating power, condensing pressure, evaporating pressure, and condensing side temperature.

[0064] The above operating data establishes a time correspondence based on the sampling time, so that the cooling load status, environmental heat exchange status and unit operating status within the same sampling period can correspond to each other.

[0065] S102. Establish operating condition reference state: Before implementing energy-saving adjustment, the controller keeps the operating parameters of the condenser fan and the spray operation unchanged, and continuously acquires the cooling load state, the ambient heat exchange state and the unit's comprehensive energy consumption within the preset observation period.

[0066] The controller determines whether the changes in cooling load, ambient wet-bulb temperature, and ambient relative humidity during the observation period are within their respective preset stable ranges.

[0067] When all the above parameters meet the corresponding stability conditions, a reference operating condition for the current control cycle is established based on the cooling load and environmental heat exchange status during the current observation period, and the unit's comprehensive energy consumption under this reference operating condition is determined as the reference comprehensive energy consumption. .

[0068] When the cooling load or ambient heat exchange conditions have not yet met the stability conditions, the controller continues to acquire operating data and postpones the establishment of the operating condition reference state until an observation period that meets the stability conditions is formed.

[0069] Through the above processing, subsequent control actions have a relatively stable operating condition reference basis, avoiding the direct use of the instantaneous operating state undergoing significant load changes or environmental changes as the starting point for evaluating control actions.

[0070] S103. Implement control actions and acquire operating data after control actions: After establishing the operating condition reference state, the controller implements control actions on at least one of the condenser fan operating parameters and spray operating parameters according to the current control parameters.

[0071] The condenser fan operating parameters may include at least one of the following: condenser fan operating frequency, number of operating units, or air volume; the spray operating parameters may include at least one of the following: spray circulation pump operating frequency, number of operating units, spray water flow rate, or spray interval period.

[0072] For example, the operating frequency of the condenser fan can be adjusted while keeping the spray operating parameters unchanged, or the operating frequency of the spray circulation pump or the spray water flow rate can be adjusted while keeping the operating parameters of the condenser fan unchanged.

[0073] After the control action is executed and a preset response time has elapsed, the controller reacquires the cooling load status, ambient heat exchange status, and unit operating status, and determines the actual comprehensive energy consumption after the control action. .

[0074] S104. Determine the operating condition disturbance during the control action: Since the terminal cooling load and external environmental heat exchange conditions may change synchronously during the implementation of the control action, the controller does not directly judge whether the current control action produces an energy-saving effect based on the increase or decrease of the comprehensive energy consumption before and after the control action, but first determines the operating condition disturbance during the control action.

[0075] Specifically, the load disturbance component is determined based on the change in the current cooling load before and after the control action relative to the cooling load corresponding to the operating condition reference state.

[0076] The environmental heat transfer disturbance component is determined based on the changes in environmental heat transfer parameters such as ambient wet-bulb temperature and ambient relative humidity before and after the control action relative to the operating condition reference state.

[0077] The operating condition disturbance quantity corresponding to the current control cycle is formed based on the load disturbance component and the environmental heat exchange disturbance component.

[0078] For example, when the terminal load demand decreases during the implementation of control actions, the compressor operating power may decrease even if the operating parameters of the condenser fan and spray system remain completely unchanged. Therefore, this change in cooling load cannot be directly used as the energy-saving effect of the current control action.

[0079] Similarly, when the ambient wet-bulb temperature decreases or the air humidity changes to favor evaporative heat transfer, the heat exchange conditions of the evaporative condenser improve, and the condensing pressure and compressor operating power may decrease accordingly. This energy consumption change caused by the change in ambient heat exchange conditions also needs to be distinguished from the energy consumption change generated by the control actions themselves.

[0080] S105. Determine the baseline energy consumption change corresponding to the operating condition disturbance: Based on the operating condition disturbance determined in S104 and the operating condition reference state established in S102, the controller determines the baseline energy consumption change expected to be caused by the change in current cooling load and environmental heat exchange conditions, assuming that the condenser fan operating parameters and spray operating parameters remain unchanged. .

[0081] Specifically, a response relationship is established between the cooling load state, the ambient heat exchange state, and the unit's overall energy consumption near the reference operating condition. This response relationship describes the change in overall energy consumption corresponding to changes in the cooling load state or the ambient heat exchange state when the control parameters remain constant.

[0082] When the unit is first put into energy-saving control and sufficient historical stable operation data has not yet been formed, an initial response relationship is established based on the unit design parameters and the corresponding data between different cooling load states, environmental heat exchange states and comprehensive energy consumption obtained in advance.

[0083] With historical stable operating data already established, the cooling load status, ambient heat exchange status, and unit comprehensive energy consumption can be obtained during multiple stable operating periods when the condenser fan operating parameters and spray operating parameters remain unchanged. The corresponding energy consumption response relationship can be determined based on the change relationship between different stable states.

[0084] When there are multiple response relationships corresponding to different cooling load states and environmental heat exchange states, select the response relationship corresponding to the current operating condition reference state and its cooling load state and environmental heat exchange state, and use the selected response relationship to determine the reference energy consumption change corresponding to the current operating condition disturbance.

[0085] After acquiring new steady-state data during unit operation, the current response relationship is updated based on this data, gradually adapting it to the actual operating characteristics of the unit. Data acquired under disturbance conditions is not used as steady-state data for updating the response relationship, to avoid incorporating energy consumption changes caused by control actions or significant operating condition fluctuations into the energy consumption response relationship corresponding to the disturbance.

[0086] The operating condition disturbance determined in S104 is matched with the response relationship to obtain the baseline energy consumption change expected to be generated by the current operating condition disturbance.

[0087] The baseline energy consumption change is used to characterize the expected change in the unit's overall energy consumption if no adjustment of the condenser fan or spray operating parameters is implemented during the current control cycle, but only changes in the actual detected cooling load and environmental heat exchange conditions occur.

[0088] S106. Determine the net energy consumption response corresponding to the control action: such as Figure 3 As shown, the comprehensive energy consumption corresponding to the reference operating condition is... The actual comprehensive energy consumption after the control action is implemented is .

[0089] The difference between the two is defined as the actual change in energy consumption: ;

[0090] in, This indicates the actual change in energy consumption before and after the control action.

[0091] Since the actual energy consumption change is affected by both control actions and operating condition disturbances, the baseline energy consumption change determined in S105 is subtracted from the actual energy consumption change to obtain the net energy consumption response corresponding to the current control action:

[0092] in, This indicates the net energy consumption response corresponding to the current control action.

[0093] When the above symbol conventions are used, if the net energy consumption response is less than zero, it indicates that after removing the expected energy consumption impact of changes in cooling load and environmental heat exchange conditions, the current control action still further reduces the unit's overall energy consumption, and therefore the current control action has an energy-saving contribution.

[0094] When the net energy consumption response is greater than zero, it indicates that the actual energy consumption change after the control action may mainly come from the decrease in cooling load or the improvement of environmental heat exchange conditions, or the energy consumption increase of the current control action itself has exceeded the amount of compressor energy consumption reduction it brings. Therefore, the overall energy consumption reduction detected on the surface cannot be directly identified as the energy-saving effect produced by the current control action.

[0095] For example, if a decrease in the unit's actual overall energy consumption is detected after a control action, and a significant decrease in the cooling load occurs simultaneously, the controller first determines the baseline energy consumption reduction expected from this load change based on the degree of cooling load reduction and the current operating condition reference state. If the actual energy consumption reduction is less than the baseline energy consumption reduction, it indicates that although the actual overall energy consumption appears to have decreased, the current control action itself has not generated a corresponding energy-saving contribution.

[0096] Conversely, if there is an additional energy reduction after deducting the baseline energy consumption change expected from changes in cooling load and ambient heat exchange conditions, then this additional reduction corresponds to the net energy saving effect of the current control action.

[0097] S107. Determine the energy-saving contribution of the control action based on the net energy consumption response: The controller determines the energy-saving contribution of the current control action based on the direction and magnitude of the net energy consumption response; the greater the energy reduction represented by the net energy consumption response, the more obvious the actual energy-saving effect brought about by the current control action after excluding the influence of changes in cooling load and changes in environmental heat exchange conditions.

[0098] When the net energy consumption response is close to zero, it indicates that the current control action has a small actual impact on the overall energy consumption, and the necessity to continue increasing the adjustment in the current direction is reduced.

[0099] When the net energy consumption response indicates an increase in overall energy consumption, it means that the current control action has not made an effective energy-saving contribution, and the adjustment amount will not continue to be increased in the same way in subsequent control cycles.

[0100] Thus, the controller obtains the evaluation results of control actions that are not directly governed by the current cooling load fluctuations and changes in the environmental heat exchange state, and uses the energy-saving contribution as the basis for subsequently determining the adjustment object, adjustment direction, and adjustment step size.

[0101] This can be understood as follows: The controller first establishes a reference operating condition state corresponding to the current cooling load state and the ambient heat exchange state. After implementing the control action, it identifies the operating condition disturbances that occur during the control period. Based on the operating condition disturbances, it determines the expected baseline energy consumption change if the current control action is not implemented. Then, it separates the baseline energy consumption change from the actual energy consumption change, thereby obtaining the net energy consumption response corresponding to the current control action itself. Based on the net energy consumption response, it evaluates the actual energy saving contribution of the current control action.

[0102] The above process enables the controller to avoid misidentifying energy consumption reductions caused by natural load decreases or improved environmental conditions as energy-saving effects from fan or spray regulation.

[0103] Example 3

[0104] like Figure 2 and Figure 4 As shown, this embodiment, based on the energy-saving contribution of the control action determined in Embodiment 2, coordinates the condenser fan and the spray circulation pump, and determines the low comprehensive energy consumption operating point corresponding to the current operating condition under the condition of satisfying the unit's operating constraints. This includes the following steps:

[0105] S201. Determine the unit adjustment energy-saving contribution corresponding to the operating parameters of the condenser fan and the spray: Under the current operating condition reference state, the controller implements control actions on the operating parameters of the condenser fan and the spray respectively.

[0106] When evaluating the operating parameters of the condenser fan, the operating parameters of the spray system are kept constant, while the operating parameters of the condenser fan are changed. The net energy consumption response and energy-saving contribution corresponding to the control action are determined according to the method in Example 2.

[0107] When evaluating the spray operation parameters, keep the condenser fan operation parameters unchanged, change the spray operation parameters, and determine the net energy consumption response and energy saving contribution corresponding to the control action in the same way.

[0108] Based on the energy-saving contribution of each control action and the corresponding adjustment of operating parameters, determine the unit adjustment energy-saving contribution of the condenser fan and spray operating parameters under the current operating conditions.

[0109] When different operating parameters are expressed using different physical quantities, the adjustment amount can be normalized according to the allowable adjustment range of the corresponding operating parameters so that the energy-saving contribution of unit adjustment of condensing fans and spray circulation pumps can be compared on a unified scale.

[0110] S202. Determine the adjustment object, adjustment direction, and adjustment step size: The controller compares the unit adjustment energy-saving contribution of the condenser fan and spray operation parameters, and prioritizes the operation parameter with the larger unit adjustment energy-saving contribution as the current adjustment object.

[0111] For the current object to be regulated, the controller determines the direction of the next control action based on the net energy consumption response corresponding to the previous control action.

[0112] If the net energy consumption response indicates a further reduction in overall energy consumption after implementing control actions in the current adjustment direction, the current adjustment direction should be maintained.

[0113] If, after implementing control actions in the current adjustment direction, the net energy consumption response indicates that the overall energy consumption has not been further reduced, the current adjustment amount should not be increased. Instead, the adjustment direction should be changed or the adjustment step size should be reduced.

[0114] As the energy-saving contribution of continuous control actions gradually decreases, the controller gradually reduces the adjustment step size to improve the accuracy of determining the operating point when approaching the low overall energy consumption region.

[0115] When the energy-saving contribution per unit of the current regulated object decreases to the preset switching condition, the controller switches to another regulated object and redetermines the corresponding regulation direction and regulation step size for that regulated object.

[0116] S203. Generate candidate operating points: Based on the adjustment object, adjustment direction and adjustment step determined in S202, adjust the operating parameters of the condenser fan or the spray operation parameters to form new candidate operating points.

[0117] like Figure 4As shown, the initial operating point can correspond to a higher overall energy consumption. The controller sequentially generates multiple candidate operating points based on the actual energy-saving contribution of continuous control actions, and prioritizes moving in the direction that can reduce overall energy consumption.

[0118] When the energy-saving contribution of a certain regulating object gradually decreases, the controller switches the regulating object or reduces the regulating step size, so that the candidate operating point gradually moves closer to the low comprehensive energy consumption region under the current operating conditions.

[0119] S204. Verify unit operation constraints for candidate operating points: For each candidate operating point formed, the controller determines whether the candidate operating point meets the unit operation constraints.

[0120] The unit operation constraints may include at least chilled water supply temperature constraints, condensing pressure constraints, compressor compression ratio constraints, and evaporative condenser heat exchange state constraints.

[0121] Among them, the chilled water supply temperature constraint is used to ensure that the unit can still meet the terminal cooling demand; the condensing pressure constraint and compressor compression ratio constraint are used to prevent the compressor from entering an unsuitable operating range in order to reduce the energy consumption of auxiliary equipment; the evaporative condenser heat exchange state constraint is used to ensure that the current air volume and spray state can maintain the required condensation heat exchange process.

[0122] When a candidate operating point meets the above unit operating constraints, the candidate operating point is taken as a valid candidate operating point, and subsequent energy-saving evaluations are carried out.

[0123] When the operating status of any unit in the candidate operating points exceeds the corresponding constraints, the candidate operating point is canceled, the controller is restored to the previous operating point that satisfies the unit operating constraints, and the adjustment direction of the corresponding operating parameters is changed or the adjustment step size is reduced before regenerating the candidate operating point.

[0124] S205. Determine whether the candidate operating point has reached the convergence condition: The controller compares the actual comprehensive energy consumption changes between consecutive effective candidate operating points and, in conjunction with the current adjustment step size, determines whether it has approached the low comprehensive energy consumption operating region.

[0125] When the overall energy consumption difference between consecutive candidate operating points is still large, it indicates that the current operating parameters still have room for further adjustment. The controller continues to determine the net energy consumption response and energy saving contribution of the next control action according to the method of Example 2, and updates the adjustment direction and adjustment step size accordingly.

[0126] When the overall energy consumption difference between consecutive candidate operating points is less than the preset energy consumption change threshold, and the current adjustment step size has been reduced to the preset range, the controller determines that the current optimization process meets the convergence condition.

[0127] S206. Determine the low comprehensive energy consumption operating point: When the convergence condition is met, the controller selects the candidate operating point with the lowest actual comprehensive energy consumption from the candidate operating points formed during the current optimization process that meet the unit operation constraints as the current low comprehensive energy consumption operating point.

[0128] The controller controls the unit's operation according to the condenser fan operating parameters and spray operating parameters corresponding to the low overall energy consumption operating point.

[0129] The low overall energy consumption operating point is not the lowest power state determined independently of the unit's cooling demand, but rather a low overall energy consumption operating state formed under the premise of meeting the chilled water supply temperature, condensing pressure, compressor operating status, and evaporative condenser heat exchange requirements, based on the current cooling load and environmental heat exchange status.

[0130] S207. Monitor changes in operating conditions and determine whether to re-establish the operating condition reference state: During the period when the unit is operating at the current low comprehensive energy consumption operating point, the controller continuously acquires the cooling load state and the ambient heat exchange state, and determines whether the current operating condition is still compatible with the operating condition when the low comprehensive energy consumption operating point was determined.

[0131] When the change in ambient wet-bulb temperature within the preset observation window exceeds the preset temperature threshold, it indicates that the ambient heat exchange conditions of the evaporative condenser have changed significantly.

[0132] When the rate of change of cooling load within the preset observation window exceeds the preset load threshold, it indicates that the terminal cooling demand has significantly deviated from the load state when the current low comprehensive energy consumption operating point was determined.

[0133] Furthermore, when the deviation between the actual energy consumption change and the baseline energy consumption change determined based on the current response relationship exceeds the preset tolerance range within multiple consecutive control cycles, it indicates that the original operating condition reference state or the corresponding response relationship can no longer accurately reflect the current unit operating status.

[0134] When any of the above-mentioned operating condition reconstruction conditions occur, the controller stops using the original operating condition reference state and maintains the current control parameters that meet the unit's operating constraints, while continuously acquiring new cooling load and ambient heat exchange states. Once the unit re-establishes an observation period that meets the stability conditions, the controller re-establishes the operating condition reference state based on this observation period, determines the new reference comprehensive energy consumption, and selects, corrects, or updates the response relationship corresponding to the new operating condition reference state based on the new stable operating data.

[0135] After reconstructing the operating reference state, the controller re-adjusts the condenser fan operating parameters and / or spray operating parameters. Based on the changes in cooling load and environmental heat exchange states before and after the control action, new operating condition disturbances are determined, and the net energy consumption response and energy-saving contribution of the control action are re-determined according to the method in Example 2. On this basis, the controller again compares the energy-saving contributions of the condenser fan and spray operating parameters, forms new candidate operating points, and performs operating constraint verification and convergence judgment, thereby re-determining the low overall energy consumption operating point corresponding to the changed cooling load and environmental heat exchange states.

[0136] Through the above processing, when energy-saving control is first implemented, an initial evaluation basis can be formed using pre-acquired operating condition-energy consumption data. During subsequent operation, stable operating data can be used to update the response relationship. When the cooling load or environmental heat exchange conditions change significantly, a new operating condition reference state is established and the corresponding response relationship is matched. Therefore, the energy-saving contribution of control actions is always evaluated based on an energy consumption change benchmark adapted to the current operating conditions, reducing the interference of dynamic load and environmental heat exchange condition changes on the judgment of energy-saving adjustment direction.

[0137] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for adaptive load regulation and energy-saving control of an evaporative condensing chiller unit, characterized in that, Includes the following steps: The cooling load status, ambient heat exchange status, and unit operating status of the evaporative condensing chiller are obtained. When the control parameters remain unchanged and the cooling load status and ambient heat exchange status meet the stability conditions, a reference operating status is established, and the reference comprehensive energy consumption is determined. Adjust at least one of the condenser fan operating parameters and spray operating parameters according to the current control parameters, and obtain the cooling load status, environmental heat exchange status, unit operating status and actual comprehensive energy consumption after the control action; The operating condition disturbance is determined based on the changes in cooling load and environmental heat exchange state before and after the control action. The operating condition disturbance is then input into the response relationship corresponding to the operating condition reference state to determine the baseline energy consumption change caused by the operating condition disturbance under the condition that the control parameters remain unchanged. Determine the actual energy consumption change relative to the reference energy consumption, subtract the reference energy consumption change from the actual energy consumption change to obtain the net energy consumption response corresponding to the current control action, and determine the energy saving contribution of the current control action based on the net energy consumption response. The adjustment object, adjustment direction and adjustment step size are determined based on the energy-saving contribution corresponding to the operating parameters of the condenser fan and the spray operation parameters. Candidate operating points are generated, and the unit operation constraints of the candidate operating points are verified. Among the candidate operating points that satisfy the unit operating constraints, the adjustment direction and adjustment step size are adjusted according to the energy saving contribution corresponding to the continuous control action until the preset convergence condition is met. The candidate operating point that satisfies the unit operating constraints and has the lowest comprehensive energy consumption is determined as the current low comprehensive energy consumption operating point, and the evaporative condensing chiller is controlled to operate according to the current low comprehensive energy consumption operating point.

2. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 1, characterized in that, The cooling load status is determined based on the chilled water supply temperature, chilled water return temperature, and chilled water flow rate; the environmental heat exchange status includes at least two of the environmental dry-bulb temperature, environmental wet-bulb temperature, and environmental relative humidity; the unit operating status includes at least two of the compressor operating power, condenser fan operating power, spray circulation pump operating power, condensing pressure, evaporating pressure, and condensing side temperature; the current cooling load is determined based on the chilled water flow rate and the temperature difference between the chilled water supply temperature and the chilled water return temperature.

3. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 2, characterized in that, Establishing the aforementioned operating condition reference state includes: During the observation period when the operating parameters of the condenser fan and the spray system remain unchanged, the cooling load status, ambient heat exchange status, and unit operating status are continuously acquired. When the changes in cooling load and ambient heat exchange are within their respective stable ranges, the operating condition reference state is determined based on the cooling load and ambient heat exchange states during the observation period, and the reference comprehensive energy consumption corresponding to the operating condition reference state is determined based on the compressor energy consumption, condenser fan energy consumption, and spray circulation pump energy consumption.

4. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 3, characterized in that, The load disturbance component is determined based on the change in the current cooling load relative to the cooling load corresponding to the reference operating condition. The environmental heat exchange disturbance component is determined based on the changes in the ambient wet-bulb temperature and ambient relative humidity relative to the reference operating condition. The operating condition disturbance is formed based on the load disturbance component and the environmental heat exchange disturbance component. The response relationship is used to characterize the correspondence between the changes in the cooling load state and the environmental heat exchange state and the changes in the overall energy consumption when the control parameters remain unchanged. The operating condition disturbance is input into the response relationship to obtain the baseline energy consumption change.

5. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 4, characterized in that, The actual overall energy consumption after the control action Compared with reference comprehensive energy consumption The difference is determined as the actual change in energy consumption. : ; The change in the baseline energy consumption is denoted as... The net energy consumption response corresponding to the current control action is determined according to the following formula. : ; The degree to which the current control action increases or decreases the overall energy consumption relative to the baseline energy consumption corresponding to the operating condition disturbance is determined based on the direction and magnitude of the net energy consumption response, and the energy-saving contribution of the current control action is determined accordingly.

6. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 5, characterized in that, By changing one of the operating parameters of the condenser fan and the spray pump while keeping the other constant, the net energy consumption response of the corresponding control action is obtained. Based on each net energy consumption response and the corresponding adjustment amount of the operating parameter, the unit adjustment energy saving contribution of the condenser fan and the spray circulation pump under the current operating conditions is determined. The energy-saving contribution per unit of adjustment is compared, and the operating parameter with the larger energy-saving contribution per unit of adjustment is adjusted first. When the energy-saving contribution per unit of adjustment corresponding to the operating parameter decreases to the preset switching condition, the adjustment object is switched.

7. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 6, characterized in that, When the net energy consumption response obtained after implementing control action in the current adjustment direction indicates a reduction in overall energy consumption, the current adjustment direction shall be maintained. When the net energy consumption response indicates that the overall energy consumption has not decreased, the current adjustment direction is changed or the adjustment step size is reduced, and the adjustment direction and adjustment step size of the next control cycle are determined based on the changes in net energy consumption response corresponding to at least two consecutive control actions. The condenser fan operating parameters include at least one of the following: fan operating frequency, number of fans in operation, or fan air volume; the spray operating parameters include at least one of the following: spray circulation pump operating frequency, number of spray circulation pumps in operation, spray water flow rate, or spray interval period.

8. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 7, characterized in that, The unit operation constraints include at least the chilled water supply temperature constraint, condensing pressure constraint, compressor compression ratio constraint, and evaporative condenser heat exchange state constraint. When the operating status of any unit corresponding to a candidate operating point does not meet the corresponding unit operating constraints, the candidate operating point is canceled, and the previous candidate operating point that meets the unit operating constraints is restored. The adjustment direction of the corresponding operating parameters is changed or the adjustment step size is reduced before a new candidate operating point is generated.

9. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 8, characterized in that, During the continuous generation of candidate operating points that meet the unit's operating constraints, the adjustment step size is reduced when the energy-saving contribution corresponding to the continued adjustment along the current adjustment direction gradually decreases. When the difference in comprehensive energy consumption between consecutive candidate operating points is less than the preset energy consumption change threshold and the adjustment step size reaches the preset minimum range, it is determined that the preset convergence condition is met, and the candidate operating point that meets the unit operation constraints and has the lowest comprehensive energy consumption is determined as the current low comprehensive energy consumption operating point.

10. The adaptive load regulation and energy-saving control method for evaporative condensing chillers according to claim 9, characterized in that, During operation at the current low overall energy consumption operating point, the cooling load status and environmental heat exchange status are continuously acquired. When the change in the cooling load status or environmental heat exchange status relative to the corresponding status when the current low overall energy consumption operating point is determined exceeds the operating condition reconstruction conditions, the current operating condition reference status is stopped, the operating condition reference status is re-established, and energy-saving adjustment is re-executed. The conditions for reconstructing the operating conditions include at least one of the following: the change in ambient wet-bulb temperature within a preset observation window exceeds a preset temperature threshold; the rate of change in cooling load within a preset observation window exceeds a preset load threshold; and the deviation between the actual energy consumption change and the baseline energy consumption change continuously exceeds a preset tolerance range.

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