Industrial cooling tower intelligent fog dispersal and water saving control system based on environmental parameter self-adaption

Abstract

The invention relates to the technical field of industrial circulating water cooling and energy conservation and environmental protection, and discloses an intelligent fog dispersal and water saving control system for an industrial cooling tower based on environmental parameter self-adaption, which comprises a cooling tower, a sensing network, a variable flow resistance spraying matrix and a controller, and the interior of the tower is divided into a central wet exchange area and an edge dry air bypass area. The controller calculates a fog dispersal target dry-wet flow ratio according to environmental parameters, solves a target water spraying density based on a pneumatic-hydraulic flow resistance coupling model, and further adjusts the variable frequency pump station and the partition valve group. The system actively adjusts the air flow resistance of a filler layer by changing the spraying flux and the effective area of a wet area, and passively reconstructs dry and wet air distribution by utilizing a parallel flow channel pressure balance principle. A mechanical air valve easy to corrode is abandoned, pneumatic parameters are regulated and controlled through hydraulic parameters, the problems that a traditional fog dispersal tower is poor in season adaptability and an executing mechanism is prone to failure are solved, and the system reliability and the energy-saving and water-saving effects are improved.

Description

Technical Field

[0001] This invention relates to the field of industrial circulating water cooling and energy-saving and environmental protection technology, specifically to an intelligent defogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters. Background Technology

[0002] Industrial cooling towers, as key waste heat emission devices in industries such as power, chemical, and metallurgy, operate under low-temperature and high-humidity weather conditions. The discharged saturated, hot, humid air mixes with the outside cold air and condenses, easily forming visible plumes. This not only causes visual pollution but also leads to icing and corrosion of surrounding facilities, as well as environmental hygiene problems caused by the spread of bacterial aerosols. To solve this problem, combined dry and wet cooling towers are widely used. Their basic principle is to mix unsaturated, hot, dry air with saturated, moist air, reducing the relative humidity of the mixture to eliminate plumes.

[0003] In existing wet and dry combined cooling tower technology systems, to adapt to seasonal weather changes and control the fogging effect, it is usually necessary to adjust the airflow ratio between the wet cooling section (packing zone) and the dry cooling section (air-cooled coils or bypass). Currently, the mainstream adjustment method is to install large mechanical air guide valves or louvers inside the air duct or at the air inlet. However, the internal operating environment of the cooling tower is harsh, constantly exposed to high temperature, high humidity, and corrosive chemicals. Under these conditions, the rotating shafts, linkages, and blades of the mechanical air valves are prone to corrosion and jamming, and scale buildup from splashing circulating water can also cause actuator malfunctions. Especially in severe winters, the water vapor condensing on the surface of the mechanical air valves easily freezes, causing the valves to freeze and lock, losing their regulating function. This not only reduces the system's operational reliability but also increases maintenance costs and downtime risks.

[0004] Furthermore, existing control strategies often employ relatively crude fixed-proportional adjustments or simple temperature threshold switching, lacking in-depth analysis of the coupling relationship between ambient air enthalpy, moisture content, and the heat and mass exchange process within the tower. This control method struggles to calculate the minimum wet-dry mixing ratio required to eliminate plumes based on real-time changing environmental parameters, leading to unnecessary high-load operation of the fan and wasted energy; or it fails to maintain a stable defogging effect when weather conditions fluctuate. Simultaneously, due to the lack of proactive and precise control over spray hydraulic parameters, traditional technologies struggle to simultaneously ensure full-load cooling performance in summer while also addressing deep defogging and maximum water conservation needs in winter, making it difficult to achieve efficient and stable operation across seasons.

[0005] Therefore, this invention proposes an intelligent defogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters to address the shortcomings of existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an intelligent defogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters. This system solves the technical problems of traditional dry-wet combined cooling towers, which rely on mechanical air guide devices to adjust the airflow ratio, leading to corrosion, scale buildup, jamming, and freezing failure of the actuators under high temperature, high humidity, and severe cold conditions. Simultaneously, it addresses the lack of precise calculation of environmental enthalpy and humidity in existing control methods, making it difficult to achieve the optimal balance between defogging effect and operating energy and water consumption under all-weather conditions, and the difficulty of a single fixed structure simultaneously meeting the needs of efficient cooling in summer and deep defogging in winter.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an intelligent defogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters, including the industrial cooling tower body, sensor network layout, variable flow resistance spray matrix device, fan drive system, and controller architecture.

[0008] The industrial cooling tower is physically divided internally into a central wet exchange zone and an edge dry air bypass zone. The central wet exchange zone, located at the tower's axis and filled with a water-spraying packing layer, serves as the primary site for heat and mass exchange. The edge dry air bypass zone surrounds the central wet exchange zone, has no water-spraying packing inside, and is used for the flow of dry air that has not undergone wet exchange. A physical partition separates the central wet exchange zone and the edge dry air bypass zone, dividing the tower's internal space vertically into two independent airflow channels: a first airflow channel and a second airflow channel.

[0009] The sensor network is used to collect operating parameters from both the exterior and interior of the cooling tower. Specifically, it includes ambient temperature and humidity transmitters and atmospheric pressure transmitters located in the air inlet area, as well as temperature sensors, flow meters, and differential pressure transmitters installed in the circulating water pipelines and inside the tower. These sensors monitor in real time the ambient dry-bulb temperature, ambient relative humidity, atmospheric pressure, inlet and outlet water temperatures, circulating water flow rate, and the static pressure difference on the air side of the central moisture exchange zone.

[0010] The variable flow resistance spray matrix device is positioned above the central wet exchange zone and is used to distribute water to the water-spraying packing layer. This device includes a variable frequency pump station unit, a zone control valve group, and an atomizing nozzle array. The atomizing nozzle array is physically divided into several independent concentric control zones on a horizontal projection plane, including, from the inside out, a first core spray zone, a second intermediate spray zone, and an edge spray zone. The variable frequency pump station unit and the zone control valve group work together to independently adjust the water supply status and spray pressure of each concentric control zone.

[0011] The controller architecture is the core computing and control unit of the system. The central processing unit is configured to receive data collected by the sensor network and calculate the target dry-to-wet mass flow rate ratio required to eliminate visible plumes based on environmental parameters. The intelligent defogging and water-saving control system for industrial cooling towers, based on environmental parameter adaptation, abandons the traditional mechanical damper-based airflow regulation mode and innovatively adopts a coupled control strategy that uses hydraulic parameters to regulate aerodynamic parameters. The central processing unit, based on an aerodynamic-hydraulic flow resistance coupling model, uses the target dry-to-wet mass flow rate ratio as input and inversely solves for the target water density in the central wet exchange zone required to achieve that ratio.

[0012] Based on the calculated target spray density, the controller sends frequency adjustment commands to the variable frequency pump station unit and opening / closing control commands to the zone control valve group. By changing the actual spray water mass flux per unit cross-sectional area and the effective spray area in the central wet exchange zone, the system actively alters the gas-liquid two-phase flow state within the spray packing layer.

[0013] As the mass flux of sprayed water increases, the effective airflow cross-section within the packing layer decreases, and the frictional resistance at the gas-liquid interface increases, thereby increasing the aerodynamic resistance of the central wet exchange zone. Under the pressure balance principle of parallel flow channels, the airflow through the high-resistance central wet exchange zone decreases, while the airflow through the relatively constant resistance edge dry air bypass zone passively increases, thus achieving physical reconstruction and precise allocation of the dry and wet air flow ratio within the tower.

[0014] Furthermore, to achieve precise defogging based on thermodynamic states, the controller executes a control strategy based on enthalpy difference trajectory optimization. The system constructs a mathematical model of the enthalpy-humidity diagram of moist air, calculates the geometric relationship between the line connecting the ambient air state point and the air state point at the outlet of the humid zone and the saturation curve, and thereby determines the minimum dry-wet mixing ratio required to eliminate plume fog.

[0015] The system uses numerical iteration to determine the unique control variable, the target spray density. When the required spray density exceeds the adjustment range of a single pump or the entire area, the system reduces the effective wet area by closing the outer edge spray zone, thereby establishing the required local high wind resistance in the remaining open area through high-flux spraying.

[0016] The intelligent defogging and water-saving control system for industrial cooling towers, based on environmental parameter adaptation, has multi-condition adaptive adjustment capabilities. Under full-load cooling conditions in summer, the controller sets the target dry-to-wet mass flow ratio to the minimum value and opens all spray zones to maximize the effective heat exchange area. At this time, the spray density per unit area is reduced, the wind resistance in the wet zone is reduced, and the incoming airflow is naturally prioritized to the central wet exchange zone to improve cooling efficiency.

[0017] In winter or late autumn, under strong defogging conditions, the controller forcibly shuts down the outer layer and part of the intermediate spray zone, leaving only the core spray zone and running the water pump at high frequency. This creates a high-density hydraulic resistance field in the core area, forcing most of the incoming airflow to flow to the edge dry air bypass zone. By mixing a large amount of dry air with a small amount of humid and hot air, the mixed gas state point is ensured to be far away from the saturation zone.

[0018] During the transitional season water-saving operation, the system limits the airflow through the wet zone by increasing the wind resistance of the wet zone. It utilizes the cold air flowing through the edge dry air bypass zone to exchange sensible heat with the water flow in the wet zone through physical partitions, thereby reducing water evaporation loss while meeting the cooling requirements.

[0019] Furthermore, the intelligent defogging and water-saving control system for industrial cooling towers, based on adaptive environmental parameters, incorporates a closed-loop feedback correction mechanism. The controller utilizes actual differential pressure data from a micro-differential pressure transmitter to online correct the parameters of the flow resistance model, compensating for resistance characteristic drift caused by packing aging or scaling. Simultaneously, it dynamically adjusts the control gain using relative humidity feedback data from the outlet mixed air, ensuring the stability and reliability of the defogging effect. Through an industrial communication interface, the system can upload a complete set of operational data, including environmental parameters, fluid state, and equipment operating frequency, to a host computer, enabling remote monitoring and data management.

[0020] This invention provides an intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters. It offers the following advantages: 1. This invention establishes an adjustable aerodynamic resistance field within the packing layer through the coordinated operation of a variable frequency pump station and a zoned control valve group. It utilizes fluid dynamics principles to passively reconstruct the airflow ratio between the central wet exchange zone and the peripheral dry air bypass zone, eliminating large mechanical moving parts within the cooling tower airflow channel. This solves the problems of traditional mechanical air valves being prone to corrosion, scale buildup, jamming, and freezing failure in winter under high temperature and humidity conditions, improving the system's operational reliability and achieving continuous stepless adjustment of airflow distribution.

[0021] 2. This invention provides a controller that calculates the critical wet-dry mixing ratio and corresponding target spray density required to eliminate visible plumes based on real-time collected ambient temperature, humidity, and heat load data. This avoids the over-mixing of air or incomplete defogging caused by empirical estimation in traditional control methods. This on-demand supply control mode limits the amount of dry air introduced to the minimum necessary level while ensuring complete elimination of plumes, reducing the fan energy consumption required to drive the dry air flow, and reducing the evaporation loss of circulating water by reducing the effective spray area.

[0022] 3. This invention constructs a concentric partitioned topology of a central humidification zone and an edge dry air bypass zone. Combined with multi-level spray partition control, this allows the system to activate all spray zones in full-load summer mode to maximize air-water contact area and ensure cooling performance. In strong defogging mode in winter, the system only activates the core high-density spray zone, using high hydraulic resistance to force most of the incoming airflow to the dry air bypass zone, thus enhancing the defogging effect. This structure enables a single device to adaptively adapt to extreme seasonal conditions, resolving the technical contradiction of conventional defogging cooling towers simultaneously achieving efficient cooling in summer and deep defogging in winter. Attached Figure Description

[0023] Figure 1 This is a system overall block diagram of the present invention; Figure 2 This is a block diagram of the electrical control system architecture of the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see the appendix Figure 1 To be continued Figure 2 The present invention provides an intelligent defogging and water-saving control system for industrial cooling towers based on environmental parameter adaptation, comprising four core components: industrial cooling tower body, variable flow resistance spray matrix device, sensor network layout, and controller architecture.

[0026] Industrial cooling towers consist of a tower structure, an air intake system, a water distribution system, and a fan drive system. The tower structure is physically divided into a central wet exchange zone and an edge dry air bypass zone in a horizontal cross-sectional space.

[0027] The central humidification zone is located at the geometric center of the tower structure, and is a cylindrical or polygonal column structure, serving as the main heat and mass exchange area. The peripheral dry air bypass zone surrounds the central humidification zone, forming a concentric sleeve structure. A vertically extending physical partition is installed between the central humidification zone and the peripheral dry air bypass zone.

[0028] The physical partition is made of non-permeable, corrosion-resistant composite material, which strictly isolates the internal space of the tower structure in the vertical direction into a first air flow channel and a second air flow channel that are independent of each other and do not interfere with each other's fluids. The first air flow channel corresponds to the internal space of the central moisture exchange zone, and the second air flow channel corresponds to the internal space of the edge dry air bypass zone.

[0029] The tower structure has circumferential or dual-sided air inlets at its bottom. These inlets are directly connected to ambient air and simultaneously connected to the bottom inlets of the central humidification zone and the edge dry air bypass zone, allowing ambient air to enter both zones simultaneously under negative pressure. A converging mixing duct is located at the top of the tower structure. The top outlets of both the central humidification zone and the edge dry air bypass zone converge into the internal mixing space of the mixing duct. A fan drive system is installed at the throat or outlet section of the mixing duct to generate a continuous negative pressure field within the tower structure, driving ambient air through both the central humidification zone and the edge dry air bypass zone.

[0030] The central humidification zone is filled with a water-spraying packing layer. This packing layer is composed of multiple layers of corrugated sheets made of polyvinyl chloride (PVC) or polypropylene (PP) stacked in an alternating pattern, providing a large surface area for air-water two-phase contact and heat and mass exchange. The packing layer has specific fluid resistance characteristics, which determine the pressure loss gradient as air flows through the central humidification zone.

[0031] The edge dry air bypass zone is designed as a cavity channel, or has low flow resistance guide plates installed inside along the airflow direction to reduce eddy current losses. No water-spraying packing layer is installed in the edge dry air bypass zone, and it remains in a state of no liquid water spraying during operation. This ensures that the air flowing through the edge dry air bypass zone only exchanges sensible heat with the physical partitions and does not undergo moisture exchange, thus maintaining a low humidity level in the air.

[0032] The variable flow resistance spray matrix device is installed above the water distribution packing layer in the central wet exchange zone. It is used to evenly distribute water to the surface of the water distribution packing layer and establish an adjustable aerodynamic resistance field. The variable flow resistance spray matrix device mainly consists of a water supply network unit, a zone control valve group, a variable frequency pump station unit, and an array of atomizing nozzles.

[0033] The atomizing nozzle array is distributed in a concentric ring or rectangular array pattern on the horizontal projection plane of the central moisture exchange zone. Based on its radial distance from the central axis of the tower structure, the atomizing nozzle array is physically divided into... Each zone is a separate concentric control area, comprising, from the inside out, a first core spray zone, a second intermediate spray zone, and a third... Edge spray zone. Among them, It is a natural number greater than or equal to 2.

[0034] Each concentric control zone corresponds to a set of independent annular water supply branch pipes. Several vertically downward high-pressure atomizing nozzles are evenly distributed on the annular water supply branch pipes at predetermined intervals. The high-pressure atomizing nozzles are solid conical or wide-angle fan-shaped nozzles. The internal flow channel structure of the high-pressure atomizing nozzles is specially designed so that the average diameter of the ejected droplets and the spray diffusion angle change monotonically with the inlet water pressure, thereby altering the physical properties of the gas-liquid interface.

[0035] The variable frequency pump station unit comprises several variable frequency centrifugal pumps connected in parallel. The suction inlets of the variable frequency centrifugal pumps are connected to the circulating water tank, and their discharge outlets converge into the main water supply pipe. The main water supply pipe connects to the first core spray zone, the second intermediate spray zone, and the third... via zone control valve groups. The ring-shaped water supply branch pipes of the edge spray zone are connected. The zone control valve group includes several proportional regulating valves or on / off solenoid valves controlled by electrical signals, which are used to independently conduct or cut off the water flow to each concentric control zone, thereby changing the effective spray area of ​​the central wet exchange zone.

[0036] The variable flow resistance spray matrix device can precisely control the actual spray water mass flux per unit cross-sectional area of ​​the central wet exchange zone by adjusting the operating frequency of the variable frequency centrifugal pump and the opening degree of the zone control valve group. The individual flow rate of the high-pressure atomizing nozzle and the inlet water pressure follow the orifice outflow equation: ; In the formula: The volumetric flow rate of a single high-pressure atomizing nozzle, expressed in cubic meters per second; The flow coefficient of the high-pressure atomizing nozzle is determined by the geometry of the internal flow channel of the nozzle. This represents the effective cross-sectional area of ​​the high-pressure atomizing nozzle outlet, in square meters. The static pressure of the water supply at the inlet of the high-pressure atomizing nozzle is expressed in Pascals. This refers to the density of the circulating cooling water, expressed in kilograms per cubic meter.

[0037] The actual spray water mass flux (i.e., spray density) in the central wet exchange zone is obtained by summing the total flow rates of the nozzles in all open areas: ; In the formula: The average water density in the central wet exchange zone is the input variable in the aforementioned fluid resistance characteristic equation, expressed in kilograms per square meter per second. This represents the number of sprinkler zones that are currently active. For the first The number of nozzles in each spray zone; For the first Volumetric flow rate of a single nozzle within a spray zone; This represents the total horizontal cross-sectional area of ​​the central humidification zone, expressed in square meters.

[0038] As the operating frequency of the variable frequency centrifugal pump increases, the inlet water pressure rises, leading to an increase in the actual spray water mass flux. With this increase, the thickness of the water film formed on the surface of the spray packing layer increases, and the number density of droplets suspended in the packing gaps increases. This results in a contraction of the free cross-section of the airflow and an increase in the frictional shear force between the gas and liquid phases, thereby achieving active adjustment of the air-side resistance in the central wet exchange zone. Since the edge dry air bypass zone does not have an atomizing nozzle array, its airflow resistance remains relatively stable, unaffected by the operating frequency of the variable frequency centrifugal pump or the status of the zone control valve group.

[0039] The sensor network layout is used to acquire real-time external environmental parameters, internal thermodynamic state parameters, and fluid dynamic parameters of the tower structure, providing high-precision data input for the controller architecture's calculations. The sensor network layout includes an environmental parameter acquisition unit, a tower internal aerodynamic resistance monitoring unit, a circulating water heat load monitoring unit, and an outlet mixing state feedback unit. All sensors within these units are connected to the input ports of the central control cabinet via shielded signal cables or industrial fieldbuses.

[0040] The environmental parameter acquisition unit is located upstream of the air inlet of the industrial cooling tower, on the windward side, in an area unaffected by the humid, hot recirculated air discharged from the tower structure itself. The unit includes an ambient temperature and humidity transmitter and an atmospheric pressure transmitter. The ambient temperature and humidity transmitter measures the dry-bulb temperature and relative humidity of the ambient air in real time. The atmospheric pressure transmitter measures the absolute atmospheric pressure under current operating conditions in real time. Both the ambient temperature and humidity transmitters are equipped with radiation shields to protect the measurements from solar radiation and thermal radiation from surrounding objects.

[0041] The tower-mounted aerodynamic resistance monitoring unit is specifically designed to monitor the airflow resistance in the central humidification zone, providing feedback on the wind resistance effect caused by the spray water. This unit includes a micro-differential pressure transmitter. The transmitter has a high-pressure tap and a low-pressure tap. The high-pressure tap is connected via an air duct to the air inlet space below the water-spraying packing layer in the central humidification zone. The low-pressure tap is connected via an air duct to the air outlet space above the water collector in the central humidification zone. The micro-differential pressure transmitter outputs the real-time static pressure difference signal on the air side of the central humidification zone, which characterizes the actual fluid resistance under the current spray water mass flux and air velocity.

[0042] The circulating water heat load monitoring unit includes an inlet water temperature sensor, an outlet water temperature sensor, and an electromagnetic flow meter. The inlet water temperature sensor probe is inserted into the center of the internal flow channel of the main water supply pipe to measure the temperature of the circulating water entering the cooling tower. The electromagnetic flow meter is installed in series on the main water supply pipe to measure the total circulating water mass flow rate. The outlet water temperature sensor probe is submerged in the water collection pan or outlet manifold at the bottom of the tower structure to measure the temperature of the cooled circulating water. Both the inlet and outlet water temperature sensors are armored platinum resistance thermometers or thermocouples.

[0043] The outlet mixing status feedback unit is located above the throat of the mixing duct or at the outlet section. The outlet mixing status feedback unit includes an outlet air temperature and humidity transmitter. The transmitter is fixed to a bracket, and its probe extends into the area where the airflow is uniformly mixed. It monitors the final state of the mixture after the humid, hot air discharged from the central moisture exchange zone and the dry air discharged from the edge dry air bypass zone have mixed, specifically including the mixed outlet air temperature and the mixed outlet air relative humidity. The mixed outlet air relative humidity data is used for closed-loop verification to determine whether the current defogging effect has reached the preset critical unsaturated state.

[0044] The controller architecture is built upon an industrial-grade programmable logic controller (PLC) or distributed control system (DCS), serving as the core for the entire system's computation and execution. At the physical level, the controller architecture includes a central processing unit (CPU), analog input modules, digital input modules, analog output modules, digital output modules, and an industrial communication bus interface. The CPU interacts bidirectionally with the analog input modules, digital input modules, analog output modules, and digital output modules via an internal bus.

[0045] The analog input module is equipped with a multi-channel high-precision analog-to-digital converter (A / D). The input ports of the analog input module are electrically connected to the ambient temperature and humidity transmitter, atmospheric pressure transmitter, micro-differential pressure transmitter, inlet water temperature sensor, outlet water temperature sensor, electromagnetic flowmeter, and outlet air temperature and humidity transmitter via shielded signal transmission lines. The analog input module receives 4-20mA standard current signals or 0-10V standard voltage signals output from the aforementioned sensors and converts the collected ambient dry-bulb temperature, relative humidity, atmospheric pressure, static pressure difference in the central humidification zone, inlet water temperature, outlet water temperature, circulating water flow rate, and mixed outlet air status parameters into digital signals, which are then transmitted to the central processing unit.

[0046] The central processing unit integrates a microprocessor and non-volatile storage media. The non-volatile storage media pre-stores a database of humid air thermodynamic properties, a mathematical model of fluid resistance characteristics, and a PID closed-loop control algorithm program. The microprocessor is configured to execute the control algorithm program, calculating the air humidity and specific enthalpy under the current operating conditions based on received real-time environmental parameters, constructing a humid air enthalpy-humidity diagram mathematical model, and calculating the target dry-to-wet air mass flow rate ratio based on the set defogging critical point. The microprocessor further uses the fluid resistance characteristic mathematical model to inversely calculate the target water density in the central moisture exchange zone required to achieve the target dry-to-wet air mass flow rate ratio, and generates corresponding control command codes.

[0047] The analog output module is equipped with a multi-channel digital-to-analog converter (D / A). The output ports of the analog output module are electrically connected to the fan inverter in the fan drive system and the water pump inverter in the variable frequency pump station unit via control cables. The analog output module converts the control command codes generated by the central processing unit into analog voltage or current signals with control frequencies, thereby adjusting the output frequencies of the fan inverter and the water pump inverter, thus controlling the fan speed and the circulating water pump speed, and achieving continuous adjustment of the total air volume and the mass flux of the spray water in the central humidification zone.

[0048] The digital output module is electrically connected to each solenoid valve in the zone control valve group via relays or solid-state switches. The central processing unit, based on the calculated target spray density and the preset spray zoning strategy, outputs high and low level switching signals through the digital output module to control the first core spray zone, the second intermediate spray zone, and the... The edge spray zone corresponds to the open or closed state of the valves on the water supply pipeline, thereby changing the effective spray area and airflow resistance distribution of the central wet exchange zone.

[0049] The industrial communication bus interface adopts an RS485 or industrial Ethernet physical interface, supporting Modbus-RTU or TCP / IP communication protocols. The controller architecture communicates with the host computer monitoring terminal through the industrial communication bus interface to achieve remote monitoring of system operating parameters, historical data storage, and alarm information push. When the outlet mixing status feedback unit detects that the relative humidity of the mixed outlet air exceeds the preset safety threshold, the central processing unit triggers the defogging failure protection logic. By adjusting the signal value of the analog output module, it forcibly increases the output frequency of the water pump inverter to increase the air resistance in the wet zone, forcing more dry air to pass through the edge dry air bypass zone.

[0050] The module for modeling the variable operating condition flow resistance characteristics of the packing layer is built into the computational logic of the central processing unit. It is used to quantify the hydrodynamic behavior of the gas-liquid two-phase countercurrent contact process inside the central wet exchange zone. The model treats the water-spraying packing layer as a porous medium with anisotropic porosity and establishes a nonlinear functional relationship between the static pressure drop on the air side, the airflow velocity, and the mass flux of the sprayed water based on the modified Ergun equation.

[0051] The water-spraying filler layer is composed of multiple layers of corrugated plates stacked in an alternating manner, forming a specific surface area. and initial porosity The system consists of a three-dimensional mesh channel. Under dry conditions with the spray system off, the resistance to airflow through the water-spraying packing layer mainly stems from the frictional resistance between the air and the packing surface, as well as the shape resistance caused by changes in the channel cross-section. Under wet conditions with the spray system on, the circulating cooling water spreads across the packing surface to form a flowing water film, and forms falling droplets in the gaps between the packing layers.

[0052] The presence of a flowing water film reduces the effective hydraulic radius of the packing channel, and the surface undulation of the water film increases the friction coefficient of the airflow. Falling droplets directly impede the momentum of the counter-flowing air. The variable-condition flow resistance model of the packing layer calculates the total air-side resistance of the central wet exchange zone. It can be decomposed into the superposition of the dry packing reference resistance term and the gas-liquid coupling additional resistance term, and its mathematical expression is as follows: ; Expanding the above items into air surface velocity and spray water quality flux Empirical correlation: ; In the formula: This represents the total air resistance, measured in Pascals. The air surface velocity, measured in meters per second, is the air velocity across the cross-section of the empty tower in the central humidification zone. This value is derived from the total air volume. After deducting the bypass air volume, divide by the cross-sectional area of ​​the central humidification zone. It can be concluded that; The mass flux of spray water per unit cross-sectional area is expressed in kilograms per square meter per second. This value is calculated from the real-time flow feedback value of the variable frequency pump station unit. This is the reference resistance term for dry packing, characterizing the pressure loss of pure air flowing through dry packing; This is an additional resistance term for gas-liquid coupling, characterizing the extra pressure loss generated by the water film contraction channel and the droplet drag effect; This is the dry resistance structural coefficient, the value of which depends on the specific surface area of ​​the packing, the corrugation angle, and the packing height, and is measured in Pascals per second per meter. Power; It is the dry velocity index, and its value ranges from 1.8 to 2.0 in turbulent flow. The wet resistance interference coefficient characterizes the gain sensitivity of spray water to airflow resistance, and its unit is a dimensional constant. The spray density influence index characterizes the nonlinearity of the effect of changes in spray water volume on wind resistance, with a value ranging from 0.5 to 1.2. The wet velocity index represents the weight of the influence of airflow velocity on the coupling resistance under wet conditions.

[0053] , , , and All parameters are pending model parameters. During the initial system debugging phase, the central processing unit controlled the variable frequency pump station unit and the fan drive system to conduct stepped variable operating condition tests, collecting multiple sets of data. The data points are used to determine the specific values ​​of the above parameters through least squares regression fitting, and then stored in a non-volatile storage medium.

[0054] The modeling module for the variable operating condition flow resistance characteristics of the packing layer reveals the physical mechanism of the central wet exchange zone as a virtual pneumatic valve: when the output frequency of the variable frequency centrifugal pump is increased by the central processing unit, the mass flux of the spray water... Increase. According to the above formula, the additional resistance term of gas-liquid coupling increases. Follow of The exponential growth of this power leads to an increase in the total air-side drag in the central humidification zone. Increase. Under the constraint of pressure balance in parallel channels, this increase in resistance forces the intake airflow into the tower to redistribute, resulting in a decrease in the airflow through the high-resistance central wet exchange zone and a passive increase in the airflow through the low-resistance edge dry air bypass zone. This achieves the technical effect of changing the air-side flow field distribution simply by adjusting the water-side parameters.

[0055] The pressure balance model of the dry-wet parallel flow channel is built into the computational logic of the central processing unit to analyze the dynamic balance between airflow distribution and flow channel resistance inside the tower structure. The airflow channel inside the tower structure is topologically abstracted into two parallel fluid branches: a central wet exchange zone branch with variable flow resistance characteristics and an edge dry air bypass zone branch with fixed flow resistance geometry.

[0056] The edge dry air bypass zone branch is considered an aerodynamic component with defined geometric parameters. Due to the absence of liquid spray interference in this area, the air-side drag of the edge dry air bypass zone... Strictly follow the laws of turbulent flow, and the dry air velocity flowing through the region. It is proportional to the square of the value. This relationship is described by the characteristic equation of the dry channel resistance: ; In the formula: The air-side resistance of airflow through the edge dry air bypass zone, measured in Pascals; The overall flow resistance coefficient of the edge dry air bypass zone is determined by the channel length, hydraulic diameter, and inlet / outlet local resistance coefficient of the edge dry air bypass zone, and is a dimensionless constant. The average density of the air flowing through this area is expressed in kilograms per cubic meter. The dry air velocity is measured in meters per second within the dry air bypass zone at the edge.

[0057] Based on the principle of parallel piping in fluid mechanics, under steady-state operating conditions, the static pressure difference between the two ends of the central wet exchange zone branch and the peripheral dry air bypass zone branch must remain equal. The system establishes the following pressure balance constraint equation: ; Based on the aforementioned packing laminar flow resistance characteristic model, the equilibrium equation can be specifically expanded as follows: ; To achieve precise control over the mixing and defogging process, the central processing unit introduces a target dry-to-wet mass flow ratio. As a control intermediate variable, the target dry-to-wet mass flow rate ratio. Defined as the dry air mass flow rate through the edge dry air bypass zone. Mass flow rate of moist air flowing through the central moisture exchange zone The ratio of the velocity to the fluid velocity. According to the fluid continuity equation, the relationship between this ratio and the flow velocity is: ; By reorganizing the above formulas, the dry air velocity can be obtained. With humid air velocity The coupling relationship is: ; In the formula: The effective cross-sectional area of ​​the central humidification zone is expressed in square meters. The effective cross-sectional area of ​​the edge dry air bypass zone is expressed in square meters.

[0058] The central processing unit constructs the target spray water mass flux by simultaneously solving the pressure balance constraint equations and the flow velocity coupling equations. The reverse solution algorithm is used. The velocity coupling equation is substituted into the right side of the pressure balance equation to eliminate the dry air velocity. The information about the velocity of moist air was obtained. Target dry-to-wet mass flow rate ratio and spray water quality flux The closed-loop equilibrium equations are: ; In the actual control loop, the central processing unit knows the current total air volume demand or the fan operating frequency (i.e., it knows the total air volume demand). and (weighted sum), and calculate the required result based on environmental parameters. The central processing unit uses numerical iteration or a pre-defined lookup table method to solve for the unique unknown control variable in the closed-loop equilibrium equations described above. That is, the target spray water mass flux .

[0059] This solution process reflects the core control logic of this system: when the demand for defogging increases, the calculated... When the pressure is increased, the pressure demand on the right side of the equation also increases. To maintain equilibrium, the left side of the equation must be increased by increasing the spray water mass flux. This increases resistance in the wet zone. This means the system automatically calculates a higher spray density command, compressing the airflow by increasing water-side resistance, forcing more air to meet the flow conditions on the right side of the equation, and thus flowing towards the edge dry air bypass zone, achieving adaptive physical reconfiguration of airflow distribution.

[0060] The environmental parameter analysis and fog elimination critical point calculation module is the first step in the control method based on enthalpy difference trajectory optimization, and is executed by the central processing unit. The main function of this module is to construct the air wet state space using the thermodynamic equation of state based on real-time external meteorological conditions, and calculate the minimum dry-wet mixing ratio required to eliminate plume fog based on the geometric characteristics of the saturation curve.

[0061] The central processing unit first reads real-time data collected by the ambient temperature and humidity transmitter and the atmospheric pressure transmitter through the analog input module, including the ambient dry-bulb temperature. relative humidity and atmospheric pressure Based on the above parameters, the central processing unit calculates the saturated water vapor partial pressure of the current ambient air according to the Goff-Glazy formula or the Magnus modified formula. Its calculation expression is: ; In the formula, The partial pressure of saturated water vapor at ambient temperature, expressed in Pascals. , , This is an empirical constant determined based on the properties of water vapor.

[0062] Then, the central processing unit calculates the actual water vapor partial pressure of the ambient air. Moisture content and enthalpy The calculation formula is as follows: ; ; ; In the formula: Moisture content of ambient dry air, expressed in kilograms of water per kilogram of dry air; Specific enthalpy of ambient air, expressed in kilojoules per kilogram; This is the specific heat capacity of dry air at constant pressure, expressed in kJ / (kg·℃). The latent heat of vaporization of water at 0℃ is expressed in kJ / kg. This is the isobaric specific heat capacity of water vapor, expressed in kJ / (kg·℃).

[0063] The central processing unit locates the state point representing the ambient air state in the enthalpy-humidity diagram (HD diagram) mathematical model constructed in its internal memory. Meanwhile, the system uses feedback from the outlet water temperature sensor... Based on the pre-defined heat exchange efficiency model within the tower, the state point of the humid and hot air at the outlet of the central humid exchange zone is estimated. Set state points Located on the saturation curve with a relative humidity of 100%, its temperature is approximately equal to The corresponding specific enthalpy is denoted as Moisture content is recorded as .

[0064] To determine the critical conditions required to eliminate visible plumes, the central processing unit performs a tangent optimization or connection truncation algorithm. This is because the mixed gas exiting from the top of the tower will mix with ambient air after leaving the duct. Further mixing causes its state change trajectory to follow the mixing point. With environmental points The connection line moves. If this connection line intersects the saturation curve, a condensation plume will be generated. Therefore, the central processing unit calculates the connection point of the environment. With state point Find the equation of the straight line and solve for the intersection of this line and the saturation curve. The intersection point. If an intersection point exists, it will be closer to the environment point. The intersection point on one side is defined as the critical saturation point. Its specific enthalpy is .

[0065] To ensure the reliability of fog removal and to reserve a safety margin, the system sets a target mixing point. enthalpy Should meet: ; In the formula, This value is a preset positive real number to ensure that the mixing state point deviates from the saturation region and enters the unsaturated region, thus providing a safety margin for fog removal.

[0066] Based on the laws of conservation of energy and mass (lever law), the central processing unit calculates the amount of energy needed to reach the target mixing point. Required dry air mass flow rate in the edge dry air bypass zone Moist air mass flow rate with central humidity exchange zone Target dry-to-wet mass flow ratio : ; In this calculation logic, since no moisture exchange occurs in the edge dry air bypass zone and it is assumed that the sensible heat exchange when passing through the airflow baffle is known or negligible, the specific enthalpy of the dry air entering the mixing zone is set. Approximately equal to the specific enthalpy of ambient air The calculated As the core control target parameter, it is passed to the subsequent aerodynamic-hydraulic flow resistance coupling solution module for inverse calculation of the required spray water mass flux. When the calculation results show When the system indicates that it can naturally dissipate fog without the need for dry air or that fog cannot be dissipated under the current environmental conditions, the system will automatically switch to the normal operating mode or the maximum fog dissipation mode.

[0067] The specific execution steps of the control strategy described in this invention are periodically executed by the central processing unit in the controller architecture, with the time interval of each control cycle set to [missing information]. The execution process mainly includes the data acquisition and target construction step S1, the flow resistance and flow rate reverse solution step S2, the multivariable actuator linkage adjustment step S3, and the closed-loop feedback correction step S4.

[0068] In step S1, the central processing unit first synchronously acquires real-time signals from the ambient temperature and humidity transmitter, atmospheric pressure transmitter, inlet water temperature sensor, outlet water temperature sensor, and electromagnetic flowmeter via the analog input module to obtain the ambient dry-bulb temperature. relative humidity Atmospheric pressure Inlet water temperature Outlet water temperature and circulating water flow Based on the above data, the central processing unit calculates the total heat dissipation load requirement under the current operating conditions. : ; In the formula, The specific heat capacity of water, The preset target effluent temperature. Simultaneously, the central processing unit calls the aforementioned environmental parameter analysis and defogging critical point calculation module, based on real-time environmental parameters ( , , Based on the characteristics of the saturation curve, the target dry-to-wet mass flow rate ratio of the edge dry air bypass zone to the central wet exchange zone required to eliminate plume fog was calculated. .

[0069] In step S2, the central processing unit, based on the determined and the estimated total air volume under the current operating conditions of the fan. Using the aforementioned physical modeling mechanism of aerodynamic-hydraulic flow resistance coupling, the required target water spray density in the central wet exchange zone is solved in reverse. The central processing unit will Substituting the pressure balance constraint equations and combining them with the fluid continuity equations: ; ; ; Through numerical iterative algorithms, under known conditions... , Given the structural constant, solving the above system of equations simultaneously yields the unique unknown control variable. This value represents the amount of air-side fluid resistance needed to establish within the tower to force the airflow to follow a specific pattern. The proportion of water flow rate per unit area that must be achieved on the surface of the water-spraying packing layer in the central wet exchange zone.

[0070] In step S3, the central processing unit calculates the target spray density. and total heat dissipation load requirements The central processing unit generates coordinated control commands for the variable frequency pump station unit, zone control valve group, and fan drive system. The central processing unit first determines... Is it within the effective adjustment range allowed by the system? .like Within this range, the system maintains the number of currently active sprinkler zones. The target output frequency of the water pump inverter remains unchanged, and is calculated according to the following formula. : ; In the formula, The rated frequency of the water pump This represents the total area of ​​the currently activated sprinkler zones. This is the rated flow rate. If the calculated... Exceeding (That is, extremely high air resistance is required, but a single pump has reached its limit), the central processing unit issues a command to shut down the outermost layer of the pump. The control valves corresponding to the edge spray zone reduce the effective wet area. This increases the actual water spray density in the remaining open areas while keeping the total water supply constant. This is to achieve higher local fluid resistance. Simultaneously, the central processing unit adjusts its operation based on the total heat dissipation load requirements. Based on the relationship with the actual air-to-water ratio, the target output frequency of the fan inverter is calculated using a PID algorithm. This ensures that overall heat exchange requirements are met while the flow is reconstructed.

[0071] In step S4, the system executes closed-loop correction logic based on state feedback. The central processing unit reads the actual differential pressure feedback from the micro differential pressure transmitter. And calculate its difference from the model-predicted pressure difference. The deviation value. If the absolute value of the deviation value exceeds the preset threshold, it indicates that the flow resistance characteristics of the packing layer have drifted (such as scaling or aging), and the system automatically introduces a correction factor. For model parameters Update: ; In addition, the central processing unit reads the mixed air relative humidity fed back from the outlet air temperature and humidity transmitter. .like If the flow rate remains consistently above the defogging safety threshold (e.g., 90%), it indicates that the current airflow distribution is not meeting the defogging requirements. The system then triggers the defogging enhancement mechanism, increasing the target dry-to-wet mass flow rate ratio in the next control cycle. Multiply by the gain factor Thus, in step S2, a larger solution is calculated. Furthermore, by increasing the water-side resistance, the airflow in the wet zone is compressed until the outlet condition meets the requirements.

[0072] The winter / late autumn strong defogging mode is designed for ambient dry bulb temperature. Below a preset low temperature threshold (e.g., 5°C) and ambient relative humidity Dedicated control logic is used for meteorological conditions exceeding a preset high humidity threshold (e.g., 80%). Under these conditions, the ambient air state point is extremely close to the saturation curve on the enthalpy-humidity chart, and the slope of the saturated water vapor partial pressure change with temperature is small. Therefore, the critical unsaturation required to eliminate visible plumes is extremely high, necessitating a very large target dry-to-wet mass flow rate ratio. .

[0073] After detecting that the environmental parameters meet the aforementioned triggering conditions, the central processing unit automatically enters the strong fog suppression control subroutine. The central processing unit calculates the parameters based on the environmental parameter analysis module... Substitute the aerodynamic-to-hydraulic flow resistance coupling model into the inverse solution. Due to the required... The values ​​are relatively large, and according to the principle of flow resistance balance, the central humidification zone must have extremely high air-side resistance. To resist the incoming airflow, most of the air is forced to flow to the edge dry air bypass zone where the resistance is relatively constant.

[0074] Calculated target spray density This will exceed the rated water spray density under normal cooling conditions. To achieve this high-density spray target and prevent pump overload, the central processing unit issues a command via the digital output module to forcibly shut down the first... The zonal control valve groups corresponding to the edge spray zone and part of the second intermediate spray zone only keep the innermost first core spray zone in the open state. This is achieved by reducing the effective spray area of ​​the central moisture exchange zone. The variable frequency pump station unit centrally transports all circulating water flow to the first core spray area.

[0075] The variable frequency pump station unit operates at near-rated or high frequencies under the control of the analog output module, causing the high-pressure atomizing nozzles in the first core spray zone to eject high-momentum droplet clusters. These high-density droplet clusters form a thick water film on the packing surface, reducing the air permeability porosity within the packing layer. The temperature drops sharply, and the interfacial friction coefficient between the gas and liquid phases increases dramatically. The first core spray zone physically forms a hydraulic and wind-resistant wall with a high pressure drop.

[0076] Due to the pressure displacement effect of the hydraulic wind resistance wall, the cold air entering the bottom of the tower undergoes drastic flow field reconstruction driven by the static pressure difference. The vast majority of the incoming airflow (e.g., 60% to 80% of the total air volume) passively bypasses the high-resistance first core spray zone and flows instead into the lower-resistance edge dry air bypass zone. The dry, cold air flowing through the edge dry air bypass zone absorbs sensible heat (if heat conduction occurs through airflow baffles) or remains isenthalpic without increasing its absolute moisture content, and flows upward at high speed. Only a small portion of the incoming airflow (e.g., 20% to 40% of the total air volume) overcomes the high resistance to pass through the first core spray zone. This portion of air undergoes high-intensity heat and mass exchange with the high-density circulating water. Although the outlet air is nearly saturated, its absolute mass flow rate... It is suppressed.

[0077] Inside the mixing duct, a large flow of dry air from the edge dry air bypass zone... With a small flow of humid air from the first core spray zone Turbulent mixing is employed. Due to the extremely high proportion of dry air, the mixed air state point rapidly moves away from the saturation curve along the mixing line on the enthalpy-humidity chart, ultimately resulting in a deeply unsaturated exhaust gas, thus completely eliminating visible plumes in low-temperature, high-humidity environments. Furthermore, the extremely high water density and flow velocity maintained in the first core spray zone effectively prevent icing of the packing material and inlet louvers under low-temperature conditions; while the closed edge spray zone, lacking water flow, physically eliminates the risk of icing.

[0078] The summer full-load cooling mode is designed for ambient dry-bulb temperatures. Temperatures exceeding a preset high temperature threshold (e.g., 20°C) or ambient relative humidity The control logic is set for meteorological conditions below a preset low humidity threshold (e.g., 50%). Under this condition, the ambient air has a strong hygroscopic capacity, and the trajectory of the state point after the exhaust humid and hot air mixes with the ambient air is located far below the saturation curve, eliminating the thermodynamic risk of generating visible plumes. At this time, the primary adjustment objective of the control system shifts from allocating the dry air ratio on demand to maximizing the evaporative heat dissipation efficiency of the central moisture exchange zone.

[0079] After detecting that the environmental parameters meet the above-mentioned summer operating conditions, the central processing unit automatically adjusts the target dry-to-wet mass flow ratio. The value is set to the minimum or zero value allowed by the system, and the maximum cooling efficiency control subroutine is entered. The central processing unit issues a command through the digital output module, simultaneously opening all valves in the zone control group that lead to the first core spray zone, the second intermediate spray zone, and the... Control valves for the edge spray zone. At this time, the effective spray area of ​​the central moisture exchange zone... Reaching the maximum value, that is .

[0080] Maintain the total circulating water flow in the variable frequency pump station unit. Under constant conditions, due to the increase in spray area, the actual spray water mass flux per unit cross-sectional area increases. The calculation relationship is as follows: ; Based on the aforementioned packing layer variable operating condition flow resistance model: ; because As the value decreases, the second term on the right side of the equation, representing the additional resistance from gas-liquid coupling, changes. The decrease indicates that, at a physical level, the cross-section of the airflow channel within the water-spraying packing layer increases, weakening the momentum resistance of the falling droplets on the airflow. This is relative to the fixed flow resistance coefficient of the edge dry air bypass zone. The overall flow resistance characteristics of the central wet exchange zone exhibit a low resistance state.

[0081] Subject to the principle of pressure balance in parallel flow channels Under the same pressure drop, the total airflow entering the bottom of the tower is controlled by [the pressure drop factor]. A passive redistribution will occur based on changes in the flow resistance ratio. More ambient air will preferentially flow towards the central moisture exchange zone, where the flow resistance is reduced, thus increasing the surface velocity of the moist air. Naturally increases, while the dry air velocity flowing through the edge dry air bypass zone increases. The corresponding reduction. This airflow distribution result ensures that the vast majority of the incoming air volume participates in the air-water heat and mass exchange process, maximizing the specific surface area of ​​air-water contact and the mass transfer driving force.

[0082] In this mode, the central processing unit locks the operating frequency of the variable frequency centrifugal pump at the rated operating point or the flow rate required by the process side via an analog output module. Simultaneously, the central processing unit starts based on the outlet water temperature. A single-loop PID control strategy is used to adjust the output frequency of the fan drive system. When the monitored... Higher than the preset target water temperature At this time, the central processing unit increases the fan speed, thereby increasing the total airflow. Because the central humidification zone is in a low flow resistance state at this time, the increased... This will primarily be converted into effective cooling air volume. The increase in [something] ensures that the cooling tower has the maximum cooling capacity under high heat load conditions in summer.

[0083] The transitional season water-saving mode is an optimized control logic designed for meteorological conditions where the ambient dry-bulb temperature and relative humidity are within a mild range (such as spring and autumn). Under these conditions, the heat dissipation load demand of industrial cooling towers is typically lower than the design peak, and the ambient air has a certain sensible heat cooling capacity. The system's control objective is to minimize the evaporation loss of cooling water while ensuring that the circulating water outlet temperature meets process requirements.

[0084] After detecting that environmental parameters have entered the transitional season range, the central processing unit activates the water-saving optimization control algorithm. The core logic of this algorithm is to utilize the variable flow resistance of the central humidification zone to precisely regulate the air mass flow rate through the humidification zone, maintaining it at only the minimum level required to meet latent heat dissipation, and directing the remaining air flow rate to the edge dry air bypass zone.

[0085] In this mode, the heat and mass exchange process inside the tower structure is transformed from simple wet evaporative cooling to a synergistic mechanism of latent heat exchange in the wet zone and sensible heat conduction through the baffles. The physical baffles located between the central wet exchange zone and the peripheral dry air bypass zone act as an intermediate heat exchange medium. The spray water flowing through the central wet exchange zone and the dry, cold air flowing through the peripheral dry air bypass zone exchange sensible heat indirectly through the physical baffles, bearing part of the heat dissipation load and thus reducing dependence on moisture evaporation.

[0086] The central processing unit performs the following specific adjustment steps: First, the central processing unit is based on the real-time collected inlet water temperature. and the set target outlet water temperature The system calculates the real-time heat load under the current operating conditions. Then, it calculates the specific enthalpy of the ambient air. and moisture content Construct a model for predicting evaporation loss rate: ; In the formula, This is the evaporation correction factor. This represents the saturated air moisture content at the outlet of the wet zone. As can be seen from the formula, under certain external environmental conditions, reducing the mass flow rate of the wet zone... This is a direct way to reduce evaporation loss.

[0087] Next, the central processing unit calculates the time required to satisfy the following conditions: Minimum wet zone air volume under constraints Based on the aforementioned pressure balance model for parallel dry and wet flow channels, the solution is obtained in reverse to limit the airflow to... The required wet zone fluid resistance value.

[0088] To establish this target resistance, the central processing unit, through a digital output module, controls the zone control valve group to close the outermost layer. In the edge spray zone, only the inner area remains operational, thereby reducing the effective spray area. Meanwhile, the central processing unit adjusts the variable frequency pump station unit to maintain a medium-to-high level of spray water mass flux over the reduced spray area. This localized high-density spraying strategy ensures the wettability and heat exchange efficiency of the packing surface in the central area, while artificially increasing airflow resistance by increasing the local droplet density and water film thickness.

[0089] Increased This process passively distributes the airflow entering the tower, forcing most of the air to flow towards the dry air bypass zone at the edge, where resistance is lower. This dry air carries away the heat transferred by the physical partitions without coming into contact with water, and ultimately dilutes the humid air within the mixing duct.

[0090] Finally, the central processing unit executes a fine-tuning closed loop based on the outlet water temperature. If it detects... This indicates insufficient cooling capacity. The system can be adjusted by fine-tuning the frequency of the variable frequency water pump or opening some valves in the intermediate spray zone to moderately reduce the cooling capacity. This allows more air to enter the humid zone to increase evaporative heat dissipation; if The system maintains its current high-resistance water-saving state, thereby achieving the best balance between water and energy consumption throughout its entire life cycle.

Claims

1. An intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters, characterized in that, include: An industrial cooling tower, wherein the interior of the industrial cooling tower is physically divided into a central wet exchange zone and an edge dry air bypass zone; The central moisture exchange zone is provided with a water-spraying filler layer, the edge dry air bypass zone is arranged around the central moisture exchange zone and has no water-spraying filler inside, and a physical partition is provided between the edge dry air bypass zone and the central moisture exchange zone. The sensor network layout is used to collect the ambient dry-bulb temperature, ambient relative humidity and atmospheric pressure outside the cooling tower in real time, and to collect the inlet water temperature, outlet water temperature, circulating water flow rate and static pressure difference on the air side of the central moisture exchange zone inside the cooling tower. A variable flow resistance spray matrix device is installed above the central wet exchange zone to distribute water to the water spraying packing layer and establish an adjustable aerodynamic resistance field. The variable flow resistance spray matrix device includes a variable frequency pump station unit, a zone control valve group, and an atomizing nozzle array. The fan drive system is used to adjust the speed of the drive motor of the exhaust fan at the top of the cooling tower; The controller architecture includes a central processing unit, which receives data collected by the sensor network layout and calculates the target dry-wet mass flow rate ratio required to eliminate plume based on the ambient dry-bulb temperature and ambient relative humidity. The central processing unit, based on the aerodynamic-hydraulic flow resistance coupling model, inversely solves for the target spray density in the central wet exchange zone required to achieve the target dry-wet mass flow rate ratio. It then sends frequency adjustment commands to the variable frequency pump station unit and opening / closing control commands to the zone control valve group. By changing the spray water mass flux and effective spray area of ​​the central wet exchange zone, it adjusts the air flow resistance in the wet zone and physically distributes the air flow ratio between the central wet exchange zone and the edge dry air bypass zone.

2. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters as described in claim 1, characterized in that, The environmental parameter acquisition unit in the sensor network layout includes: An ambient temperature and humidity transmitter is installed on the windward side upstream of the air inlet of the cooling tower to measure the ambient dry-bulb temperature and the ambient relative humidity. An atmospheric pressure transmitter installed in the air inlet area of ​​the cooling tower is used to measure the atmospheric pressure. The central processing unit receives the ambient dry-bulb temperature, ambient relative humidity, and atmospheric pressure through an analog input module, and calculates the specific enthalpy and moisture content of the ambient air by combining the saturation curve.

3. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 1, characterized in that, The circulating water heat load monitoring unit in the sensor network layout includes: An inlet water temperature sensor installed in the center of the flow channel inside the main water supply pipe is used to monitor the inlet water temperature; The outlet water temperature sensor is installed in the cooling tower water collection pan or outlet water manifold to monitor the outlet water temperature; An electromagnetic flow meter, installed in series on the main water supply pipe, is used to monitor the flow rate of the circulating water; The central processing unit calculates the total heat dissipation load requirement based on the ambient dry-bulb temperature, the ambient relative humidity, the atmospheric pressure, and the preset target outlet water temperature.

4. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 1, characterized in that, The structural features of the variable flow resistance spray matrix device are as follows: The atomizing nozzle array is physically divided into N independent concentric control areas on the horizontal projection plane of the central moisture exchange zone, including a first core spray area, a second intermediate spray area, and an Nth edge spray area arranged sequentially from the inside out. The zone control valve group includes multiple independently controlled solenoid valves or regulating valves, which respectively control the water supply branch pipes leading to each concentric control zone; The variable frequency pump station unit includes several variable frequency centrifugal pumps connected in parallel. The central processing unit controls the actual spray water mass flux and effective spray area per unit cross-sectional area of ​​the central wet exchange zone by adjusting the operating frequency of the variable frequency centrifugal pumps and the number of opening zones of the control valve group.

5. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 4, characterized in that, The central processing unit executes the following defogging control strategy based on enthalpy difference trajectory optimization: The central processing unit constructs a mathematical model of the enthalpy-humidity diagram of humid air, calculates the line connecting the ambient air state point and the air state point at the outlet of the humid zone, and solves the critical relationship between the line connecting the ambient air state point and the air state point at the outlet of the humid zone and the saturation curve, and determines the minimum dry-wet mixing ratio required to eliminate plume fog, i.e., the target dry-wet mass flow rate ratio. The central processing unit uses a pre-stored variable-condition flow resistance model of the packing layer and the pressure balance equation of the dry and wet parallel flow channels to iteratively solve for the unique control variable, namely the target water spray density, with the target dry-wet mass flow ratio as the input variable. When the calculated target water spray density is within the effective adjustment range, the central processing unit adjusts the frequency of the variable frequency pump station unit. When the target water spray density exceeds the range, the central processing unit controls the zone control valve group to close the outer Nth edge spray zone, reduce the effective spray area and increase the water spray density of the remaining area.

6. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 1, characterized in that, The central processing unit is configured with multiple adaptive operating modes, including a summer full-load cooling mode: When the ambient dry-bulb temperature is higher than a preset high-temperature threshold or the ambient relative humidity is lower than a preset low-humidity threshold, the central processing unit sets the target dry-wet mass flow rate ratio to a minimum or zero. The central processing unit controls the zone control valve group to open all valves leading to the central humidification zone; The central processing unit controls the fan drive system and performs PID regulation based on the outlet water temperature.

7. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 1, characterized in that, The sensor network layout also includes: The tower internal aerodynamic resistance monitoring unit includes a micro differential pressure transmitter. The high-pressure tap of the micro differential pressure transmitter is connected to the bottom of the water-spraying packing layer, and the low-pressure tap is connected to the top of the water collector. It is used to monitor the static pressure difference on the air side of the central humidification zone in real time. The outlet mixing status feedback unit includes an outlet air temperature and humidity transmitter installed at the mixing duct to monitor the relative humidity of the mixed outlet air; The central processing unit corrects the parameters of the flow resistance characteristic model online based on the deviation between the actual monitored static pressure difference and the model predicted pressure difference. When the relative humidity of the mixed outlet air is higher than the safety threshold, the central processing unit automatically increases the gain coefficient of the target dry-wet mass flow rate ratio.

8. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 4, characterized in that, The control logic of the central processing unit in the strong defogging mode during winter or late autumn is as follows: When the ambient dry-bulb temperature is lower than a preset low-temperature threshold and the ambient relative humidity is higher than a preset high-humidity threshold, the central processing unit calculates a high target dry-wet mass flow rate ratio. The central processing unit controls the partition control valve group to forcibly close the Nth edge spray zone and part of the second intermediate spray zone, leaving only the innermost first core spray zone open. The central processing unit controls the variable frequency pump station unit to operate at high frequency, forming a hydraulic and wind resistance wall in the first core spray area, forcing most of the incoming airflow to flow to the edge dry air bypass area.

9. The intelligent anti-fogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 1, characterized in that, The physical partition is made of non-permeable and thermally conductive composite material, which isolates the internal space of the tower into a first airflow channel and a second airflow channel in the height direction. During the transitional season water-saving mode, the central processing unit increases the spray water mass flux of the central wet exchange zone to increase the wind resistance of the wet zone, restricts the air flow through the wet zone, and utilizes the dry air flowing through the edge dry air bypass zone to perform indirect sensible heat exchange through the physical partition.

10. The intelligent defogging and water-saving control system for industrial cooling towers based on adaptive environmental parameters according to claim 1, characterized in that, Also includes: An industrial communication bus interface is used to connect the controller architecture to a host computer monitoring terminal; The central processing unit uploads system operation status data in real time through the industrial communication bus interface. The system operation status data includes: ambient temperature and humidity, inlet and outlet water temperature, circulating water flow rate, static pressure difference of the central humidification zone, operating frequency of the variable frequency pump station unit, switching status of the zone control valve group, fan operating frequency, and relative humidity of the mixed outlet air.

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