A control method and system for a ventilation and air conditioning system of a main plant building of a thermal power plant

Abstract

The present application relates to a kind of control method and system of thermal power plant main plant ventilation and air conditioning system, belong to environmental control technical field, system includes data acquisition layer, control layer and execution layer;The data acquisition layer is in real time by sensing network Acquisition all key parameters required for control decision;The control layer includes strategy analysis decision module and control instruction execution module, the strategy analysis decision module exports current optimal system operation mode instruction and specific control set value for each execution device;The control instruction execution module is used to convert the instruction exported by strategy analysis decision module into the identifiable signal of each execution device controller, and issue execution;The execution layer is the execution device to be controlled, for realizing the full-spectrum environmental regulation from natural ventilation to mechanical refrigeration.The present application is by method innovation and not large-scale equipment modification, constructs an intelligent, collaborative, adaptive thermal power plant main plant environmental control system.

Description

Technical Field

[0001] This invention relates to the field of environmental control technology, and in particular to a control method and system for the ventilation and air conditioning system of the main building of a thermal power plant. Background Technology

[0002] The main building of a thermal power plant is the core building of the plant. Its interior space is large and complex, and it is densely packed with high-heat-generating equipment such as steam turbine generator sets, various high-voltage motors, transformers, and high-temperature steam pipes. This results in strong convection and thermal radiation inside the building, forming a significant vertical temperature gradient (thermal stratification). That is, a large amount of waste heat accumulates in the upper space of the building, while the lower working areas (such as the turbine operating floor and the vicinity of the central control room) need to maintain a relatively suitable temperature and air quality to ensure the work efficiency of the operators and the safe and reliable operation of the equipment.

[0003] To cope with this complex thermal environment, thermal power plants both domestically and internationally generally adopt a combined environmental control scheme in their main plant buildings, which mainly includes the following three subsystems:

[0004] Roof natural ventilators: Utilizing the principle of thermal pressure, when the air inside the factory is heated and rises, the hot air is exhausted to the outside through operable ventilators on the roof (such as streamlined or spherical ventilators), while outdoor air is introduced through air inlets at the bottom. Their advantages include energy saving, no power required, and an effective means of removing excess heat from the upper parts of the building.

[0005] Mechanical ventilation system: Consists of supply fans installed on the side walls or bottom of the plant and exhaust fans on the roof, which force airflow through mechanical power. Its functions include providing fresh air to the work area, diluting harmful gases or dust, and providing emergency ventilation in specific areas (such as cable trays and battery rooms).

[0006] Layered air conditioning or field air conditioning system: Air conditioning outlets (such as swirl nozzles, nozzles, etc.) are usually set in the lower areas where personnel activities are frequent and equipment is sensitive. The downward jet of cold air creates a temperature and humidity environment that meets the requirements in the work area, while the upper space is not controlled or only heat is exhausted.

[0007] The main problems and shortcomings of existing technologies:

[0008] However, in actual engineering applications and operation management, the above three subsystems are usually designed, installed, and controlled separately by different disciplines (HVAC, electrical, and thermal control), lacking effective logical coordination and unified optimization management, resulting in an operational effect of "1+1+1<3". Specific problems and shortcomings are as follows:

[0009] Inefficient energy utilization and conflicting operating modes:

[0010] Unnecessary air conditioning energy consumption: During transitional seasons and even winter, when outdoor air temperatures are low and there is natural cooling potential, air conditioning systems may still operate at the set temperature (e.g., to maintain a constant local temperature) due to simple or independent control systems, failing to fully utilize outdoor cold air and thermal pressure ventilation for "free cooling." During periods with natural ventilation, simple air conditioning temperature control strategies can waste up to 30% to 50% of cooling energy consumption.

[0011] Ventilation modes can cancel each other out: the operation of mechanical supply and exhaust systems and natural ventilators can cause airflow interference. Forcibly opening roof ventilators without organized air supply may disrupt the designed thermal pressure flow field, instead drawing hot air from above into the work area, reducing heat dissipation efficiency, and even increasing the air conditioning load. This "internal friction" caused by the lack of overall airflow organization optimization is common in existing independent control systems.

[0012] The control objective is singular, lacking multi-parameter collaborative decision-making.

[0013] Most existing control systems use "temperature" as a single or primary control objective, such as starting and stopping the air conditioner based solely on the temperature at a certain point in the work area. This control strategy ignores the coupled effects of multiple parameters, including outdoor meteorological conditions (temperature, enthalpy), thermal stratification within the plant (temperature difference ΔT), dynamic changes in equipment heat load, and indoor air quality (such as dust concentration).

[0014] The result is often control lag or overreaction. For example, when equipment starts or stops, causing a sudden change in heat generation, a single temperature feedback control will respond slowly; or when fresh air is introduced when the outdoor air enthalpy is high (high temperature and high humidity), it will unnecessarily increase the load on the air conditioning dehumidification and cooling.

[0015] Low level of intelligence, unable to achieve dynamic optimization operation:

[0016] Current technologies lack an intelligent decision-making center capable of comprehensively processing multi-source information and possessing multiple preset operating strategies. Each subsystem essentially operates independently, or only involves simple manual / time-sequential linkage. There is a lack of continuous accumulation and learning optimization capabilities for operational data. The system cannot adaptively adjust control parameters (such as mode switching thresholds) by comparing energy consumption performance under different strategies, resulting in a lack of sustained improvement in long-term energy efficiency.

[0017] The reasons and difficulties for the above-mentioned problems and shortcomings are as follows:

[0018] The underlying cause of these problems lies in the fact that traditional design and management models treat ventilation and air conditioning as independent functional units, rather than as an "integrated system" serving the same environmental goal. The main difficulties encountered in solving these problems include:

[0019] System modeling is difficult: the airflow organization and heat transfer process in tall, open factory buildings are extremely complex and difficult to describe accurately with simple mathematical models, which poses a challenge to designing a universally applicable collaborative control algorithm.

[0020] Multi-objective optimization trade-offs: How to balance multiple sometimes conflicting objectives such as "energy saving", "thermal comfort" and "air quality" within the same set of control logic is the core challenge in strategy formulation.

[0021] Compatibility with existing systems: The key to whether a technical solution can be practically applied is how to achieve a leap in energy efficiency through optimized control strategies without making large-scale modifications to the main plant structure and existing equipment. Summary of the Invention

[0022] To address the aforementioned technical problems and overcome the shortcomings of existing environmental control systems in the main building of thermal power plants, such as independent operation of various environmental control systems, single control strategies leading to energy waste, poor environmental control effects, and difficulties in multi-objective coordination, this invention provides a control method and system for the ventilation and air conditioning system of the main building of a thermal power plant.

[0023] A control system for the ventilation and air conditioning system of the main building of a thermal power plant includes a data acquisition layer, a control layer, and an execution layer;

[0024] The data acquisition layer collects all the key parameters required for control decision-making in real time through a sensor network.

[0025] The control layer includes a strategy analysis and decision module and a control instruction execution module. The strategy analysis and decision module contains a multi-mode collaborative operation strategy library, receives data from the sensor network, judges the stored operation modes based on priority and conditions, and outputs the current optimal system operation mode instruction and specific control settings for each execution device.

[0026] The control command execution module is used to convert the commands output by the strategy analysis and decision-making module into recognizable signals for each execution device controller, and then send them out for execution.

[0027] The execution layer is a controlled execution device used to achieve full-spectrum environmental regulation, from natural ventilation to mechanical refrigeration.

[0028] Furthermore, the implementing equipment includes roof natural ventilators, supply fans, exhaust fans, and a stratified air conditioning system. Roof natural ventilators: their blade opening can be continuously or in stages adjusted from 0% to 100%. Mechanical supply and exhaust fans: their motors are equipped with variable frequency drives (VFDs) to achieve stepless adjustment of airflow. Stratified air conditioning system (air handling units (AHUs) or local air conditioning units): it has cooling, heating, and air supply modes, and the airflow (fan frequency) and air temperature are adjustable.

[0029] Furthermore, the data acquisition layer includes an environmental parameter acquisition unit, a meteorological parameter acquisition unit, and an equipment status and load acquisition unit.

[0030] Furthermore, the environmental parameter acquisition unit includes:

[0031] Lower working area temperature and humidity sensors: located in the working area, used to monitor the core thermal comfort parameters of temperature T_w and relative humidity RH_w in the personnel activity area;

[0032] Upper space temperature sensor: Located in the area where hot air gathers, used to monitor the upper space temperature T_u, and calculate the temperature difference ΔT using T_u and T_w;

[0033] Dust concentration sensor in the work area: placed near the coal mill layer, coal conveyor belt or main inspection passage, to monitor the concentration of inhalable particulate matter C_d in the air.

[0034] Furthermore, the meteorological parameter acquisition unit is installed on the roof of the main plant or in an unobstructed area to collect at least the outdoor dry-bulb temperature T_out and relative humidity to obtain the enthalpy value H_out.

[0035] Furthermore, the equipment status and load acquisition unit obtains data from the power plant's distributed control system or equipment controller, including the real-time opening degree of the roof natural ventilator, the operating frequency and start / stop status of the mechanical supply / exhaust fans, and the operating mode and set parameters of the air conditioning unit.

[0036] Furthermore, the equipment status and load acquisition unit obtains data from the equipment controller through the power plant's distributed control system to estimate the real-time equipment heating load Q_equip in the plant. The equipment heating load Q_equip is used as a feedforward input to predictively adjust the base frequency setpoint of the mechanical supply and exhaust fans or the aggressiveness of the ventilation strategy when selecting or switching operating modes.

[0037] Furthermore, the control layer also includes a data storage and self-optimization module, which continuously stores system operation data and energy consumption data, and periodically runs optimization algorithms to compare actual energy consumption with theoretical optimal values ​​or historical best values ​​under different external conditions, fine-tunes key threshold parameters in the strategy library, and realizes the system's incremental self-optimization.

[0038] A control method for the ventilation and air conditioning system of the main building of a thermal power plant, comprising:

[0039] Step 100, Real-time Data Acquisition and Fusion: Synchronously acquire all sensor data and device status, and perform validity verification and data smoothing processing;

[0040] Step 200, Intelligent decision-making for operating mode: The multi-mode collaborative operation strategy library makes a step-by-step and priority judgment. The multi-mode collaborative operation strategy library defines several preset joint operation modes. Each mode corresponds to a control logic for the collaborative work of each execution device. The control switching of the mode is controlled according to the parameters T_out, H_out, T_u, T_w, ΔT, C_d and Q_equip.

[0041] Step 300, Control command generation and issuance: Based on the selected mode, generate a set of control commands containing the target status of each device and issue them to the field execution devices;

[0042] Step 400, Monitoring and Adaptive Optimization: Monitor the execution effect of instructions and energy consumption data, and automatically or semi-automatically optimize the threshold parameters in the strategy library through long-term data learning.

[0043] Furthermore, the preset joint operation mode includes:

[0044] Dust control priority mode, judgment condition: dust concentration in any work area exceeds the safety limit, action: regardless of the current temperature control mode, immediately enhance the lower air supply in the affected area to form a positive pressure barrier, and activate the dust exhaust fan in that area.

[0045] Nighttime ventilation and cold storage mode: Judgment conditions: During non-working hours, the outdoor dry-bulb temperature T_out < the upper space temperature T_u, and the working area temperature T_w is higher than the preset nighttime setting value. Action: Start some mechanical supply and exhaust fans and open the roof ventilator appropriately to use the low-temperature nighttime air to cool the entire factory structure and store cold energy to reduce the air conditioning load for the next day.

[0046] Natural ventilation-dominated mode: Judgment conditions: The outdoor dry-bulb temperature T_out is lower than the first set temperature threshold and ΔT > the first temperature difference threshold. Actions: Turn off or minimize the air conditioning cooling / heating; Based on the ΔT value, dynamically calculate and adjust the optimal opening of the roof ventilator through a lookup table method or PI control algorithm; At the same time, start some exhaust fans to form a combined heat dissipation flow field with thermal pressure ventilation as the main method and mechanical exhaust ventilation as the auxiliary method.

[0047] Air conditioning and ventilation coordinated mode: Judgment conditions: The outdoor dry bulb temperature T_out is between the first and second set temperature thresholds, or ΔT is too small to drive effective thermal pressure ventilation. Action: Start the stratified air conditioning system to ensure the set temperature T_w of the lower working area; at the same time, according to the upper space temperature T_u, dynamically adjust the opening of the roof ventilator or the frequency of the mechanical exhaust fan to orderly and auxiliaryly discharge the upper residual heat that the air conditioning system could not handle, and prevent excessive heat accumulation.

[0048] Air conditioning-dominated closed mode: Judgment conditions: outdoor dry bulb temperature T_out > second set temperature threshold, or enthalpy H_out > indoor set air enthalpy. Actions: shut down roof ventilators to minimize infiltration into the building envelope; rely entirely on the air conditioning system to bear the indoor cooling load; mechanical ventilation only maintains the minimum necessary number of fresh air exchanges.

[0049] The beneficial effects of this invention are reflected in:

[0050] 1. Significant energy saving and consumption reduction: By intelligently sensing outdoor climate conditions and indoor thermal stratification, it effectively utilizes free outdoor cold air to replace or partially replace mechanical refrigeration. This avoids the energy waste caused by the continuous operation of air conditioning when outdoor conditions are suitable due to independent control of each system in existing technologies. Coordinated control avoids conflicts between mechanical air supply and natural ventilation airflow, ensuring smooth and efficient thermal pressure ventilation. Dynamic adjustment of the ventilator opening matches the exhaust volume with the real-time heat load, eliminating energy loss caused by excessive or insufficient ventilation.

[0051] 2. Comprehensive Improvement in Environmental Control Quality and Reliability: The system not only controls temperature but also prioritizes dust concentration control. When dust levels exceed limits, a dedicated ventilation and dilution procedure is immediately triggered to ensure occupational health and safety, achieving an upgrade from single-objective thermal comfort control to a comprehensive "safety-health-comfort" multi-objective guarantee. Furthermore, by introducing feedforward control based on equipment load (Q_equip), the system can predict the changing trends of major heat sources within the plant, thereby adjusting ventilation or air conditioning strategies in advance. This significantly reduces the inherent lag of traditional pure feedback control, resulting in smaller temperature fluctuations and a more stable environment in the work area. Simultaneously, the system's robustness in handling complex operating conditions is enhanced: a pre-set multi-mode strategy library covers various typical operating conditions, from extreme cold to extreme heat, and from low load to full load. The system automatically selects the most suitable mode based on real-time data, reducing reliance on manual intervention and lowering the risk of environmental out-of-control due to improper operation.

[0052] 3. Intelligent and self-optimizing system operation

[0053] Simplified operation, achieving "one-click optimization": The complex task of monitoring and operating multiple subsystems such as ventilators, fans, and air conditioners separately, which originally required operators to do so, is integrated into an intelligent process with automatic decision-making by a central strategy database. This greatly simplifies daily operation and management, and reduces the difficulty and workload for personnel.

[0054] It possesses parameter self-learning and continuous optimization capabilities: By recording operational data and energy consumption over a long period, the system can periodically analyze and adaptively fine-tune the threshold parameters for mode switching (such as temperature threshold and temperature difference threshold). This allows the system to self-adjust to adapt to the microclimate, equipment characteristic changes, or operating habits of a specific power plant, ensuring that long-term energy efficiency does not decline and may even continue to improve, thus solving the pain point of poor long-term applicability of fixed parameter control systems.

[0055] 4. Advantages in terms of economy and feasibility

[0056] Low retrofit cost and high return on investment: This solution is mainly based on software logic innovation and control upgrades of existing equipment, without the need for large-scale replacement or addition of expensive equipment such as HVAC main units. The retrofit cost of adding sensors and controllers is limited, while the resulting energy-saving benefits (especially electricity cost savings) are significant, the investment payback period is short, and the economic benefits are obvious.

[0057] Flexible deployment and strong compatibility: This solution can be embedded as an independent intelligent control module into the existing building automation system (BAS) or distributed control system (DCS) of power plants. It has standard requirements for the interface of existing equipment, and the implementation process has little interference with the normal operation of the power plant. It is easy to promote and apply in new construction or renovation projects. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the system structure of the present invention.

[0059] Figure 2 This is a flowchart of the collaborative control method of the present invention.

[0060] Figure 3 This is a schematic diagram of the decision logic of the multi-mode collaborative operation strategy library of the present invention. Detailed Implementation

[0061] The technical solutions of 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.

[0062] Example 1: Refer to Figure 1 As shown, this embodiment provides a basic implementation method for a coordinated control system for ventilation and air conditioning in the main building of a thermal power plant, which mainly solves the problems of high energy consumption and uncoordinated thermal environment control caused by the independent operation of each subsystem.

[0063] 1. System Composition and Deployment. The system is deployed in the main power plant building (taking the turbine hall of a 600MW unit as an example) as follows:

[0064] 1) Data Acquisition Layer:

[0065] Temperature sensor for lower working area: A Pt100 platinum resistance temperature sensor is selected and installed on a column next to the main inspection passage of the operating personnel on the turbine operating floor (elevation +12.6m). A total of 8 measuring points are set up, and the average value is taken as T_w. The installation height is 1.5m above the ground.

[0066] Upper space temperature sensor: Select the same type of sensor and place it in the four corner areas of the lower chord of the main plant building (elevation +30m), with a total of 4 measuring points. Take the average value as T_u.

[0067] Outdoor weather station: Installed on the unobstructed roof outside column A of the main plant building, containing temperature and humidity sensors, measuring T_out in real time and calculating the enthalpy value H_out.

[0068] 2) Execution layer:

[0069] Roof natural ventilators: 24 streamlined, electrically operated ventilators are evenly distributed on the roof of the turbine hall. Their electric actuators are controlled by 4-20mA analog signals and can achieve stepless adjustment from 0° (fully closed) to 90° (fully open).

[0070] Mechanical supply / exhaust fans: The factory originally had 4 supply fans and 6 exhaust fans, all of which were centrifugal fans equipped with frequency converters (VFDs). The VFDs accept 4-20mA signals to control the fan frequency (0-50Hz).

[0071] Layered air conditioning system: The turbine room operating floor is equipped with 4 combined air handling units (AHU), each with an air supply volume of 50,000 m³ / h. All units have cooling, heating and air supply modes, and the air supply temperature and fan frequency can be set through the DDC controller.

[0072] 3. Control Layer:

[0073] Field controller: An industrial programmable logic controller (PLC), such as the Siemens S7-1500 series, is used. All sensor signals (4-20mA / Modbus RTU) are connected to its analog and communication modules. All actuator control signals are output from it.

[0074] Monitoring server and human-machine interface (109, 110): Set up an industrial control computer in the central control room as a monitoring server, run configuration software (such as WinCC), and configure an operator station for display and manual intervention.

[0075] 2. Implementation of control methods. Refer to... Figure 2 and Figure 3 The following control logic is programmed into the PLC, with the control cycle set to 5 minutes:

[0076] Step S100: Data acquisition: The PLC periodically reads all sensor values, performs filtering (e.g., takes the 5-minute moving average), and calculates key parameters: ΔT = T_u - T_w, H_out.

[0077] Step S200: Mode Decision (Core): The strategy library presets the following thresholds: First temperature threshold = 18℃, Second temperature threshold = 28℃, Effective thermal pressure ventilation temperature difference threshold ΔT_th = 8℃.

[0078] (1) Pattern judgment (refer to) Figure 3 First, determine if it is within working hours (e.g., 06:00-22:00). If it is within working hours, execute the following logical decision tree:

[0079] Determine C_d (not yet connected in this embodiment, considered normal).

[0080] Determine if the conditions for Mode A are met: If T_out≤18℃ and ΔT>8℃, then enter Mode A (natural ventilation dominant).

[0081] If mode A is not met, then determine whether mode B is met: if T_out≤28℃, then enter mode B (air conditioning and ventilation in tandem).

[0082] Otherwise, enter mode C (air conditioning dominant).

[0083] During non-working hours, if T_out < T_u and T_w > 20℃, then enter mode N (nighttime ventilation and cold storage).

[0084] (2) Generation of mode execution instructions:

[0085] Mode A Instructions: ① Send a command to the AHU's DDC to set it to "supply air" mode, reducing the fan frequency to the lowest setting (20Hz). ② Calculate the target opening of the roof ventilator based on the real-time ΔT value using a preset lookup table (e.g., ΔT=8°C corresponds to 30% opening, ΔT=15°C corresponds to 70% opening, etc.), and output the corresponding 4-20mA signal. ③ Start two exhaust fans, fixing the frequency at 35Hz.

[0086] Mode B Instructions: ① Send a command to the AHU's DDC to set it to "Cooling" mode, with the supply air temperature set to 24℃. The fan frequency will be automatically adjusted to ensure the supply air temperature. ② Adjust the roof ventilator opening according to the T_u value (e.g., 20% opening when T_u < 35℃, 40% opening when T_u ≥ 35℃). ③ Start one exhaust fan at a frequency of 30Hz.

[0087] Mode C Instructions: ① Send a command to shut down all roof ventilators (0% opening). ② AHU operates at full cooling capacity, ensuring T_w ≤ 26°C. ③ Mechanical supply and exhaust fans maintain only the frequency required to meet the minimum fresh air volume (approximately 25Hz).

[0088] Mode N Instructions: ① Turn on all roof ventilators to a fixed opening of 50%. ② Start 2 supply fans and 3 exhaust fans, all at a frequency of 40Hz, and automatically stop after running for 4 hours.

[0089] Step S300: Instruction Issuance: The PLC synchronously sends the generated instruction set to each execution device through the output module and communication network.

[0090] Step S400: Monitoring: The system records the hourly pattern distribution, power consumption of major equipment, and average T_w and T_u values, generating reports and trend charts on the HMI for operators to analyze.

[0091] Function and Effect: This embodiment, through the aforementioned hardware and software deployment and control logic, achieves basic coordination of different ventilation and cooling methods within the main plant. On a spring day, when T_out = 16℃ and ΔT = 10℃, the system automatically enters Mode A, maintaining the working area temperature below 25℃ using natural ventilation. The four AHUs only need to operate in air supply mode, and it is estimated that this will save approximately 60% of the air conditioning cooling power consumption compared to traditional constant temperature control on that day.

[0092] In Example 1, the specific mode settings of its strategy library are as follows:

[0093] A strategy library containing at least three basic operating modes is preset in the control system, and mode selection and switching are performed according to the following logic based on the T_out, T_u, and T_w parameters:

[0094] First mode (natural ventilation dominant): When T_out is lower than the first preset threshold and ΔT is greater than the preset temperature difference threshold, the roof natural ventilator is turned on, and the air conditioning system is stopped or kept in a minimum operating state.

[0095] Second mode (air conditioning and ventilation coordination): When T_out is between the first preset threshold and the second preset threshold, or ΔT is less than or equal to the preset temperature difference threshold, the air conditioning system is controlled to start to maintain T_w within the set range, and the roof natural ventilator is controlled to operate at a lower opening degree than the first mode, or / and the mechanical exhaust fan is started to assist in heat dissipation.

[0096] The third mode (air conditioning dominant): When T_out is higher than the second preset threshold, the roof natural ventilator is turned off and the air conditioning system is controlled to bear the entire indoor cooling load.

[0097] The above model clearly defines how to logically and conditionally switch and combine different functional subsystems (natural ventilation, mechanical ventilation, air conditioning) based on specific and quantified environmental conditions (T_out and ΔT), thereby forming a continuous and optimized control spectrum from "completely free cooling" to "completely mechanical refrigeration", which directly solves the problems of "operation mode conflict" and "low energy utilization efficiency".

[0098] Dynamic control of rooftop natural ventilators: In either the first or second mode, the system dynamically calculates and adjusts the opening angle (or degree of opening) of the rooftop natural ventilators based on the real-time calculated ΔT value, using a lookup table or proportional-integral (PI) control algorithm, to match the exhaust volume with the current plant heat load. Simply "opening" or "closing" the ventilator is a coarse control method. This feature upgrades the ventilator operation from a "switching quantity" to an "analog quantity," enabling refined and on-demand adjustment of natural ventilation capacity. This is a key technology to ensure efficient and stable airflow organization in natural or mixed ventilation modes, avoiding insufficient or excessive airflow, and a crucial operation for putting collaborative control from concept to practice.

[0099] 1. Dust Control Priority Mode (Highest Priority): Judgment Condition: Dust concentration C_d in any work area exceeds the safety limit. Action Execution: Regardless of the current temperature control mode, immediately increase the lower air supply in the affected area (increase the air conditioning air volume or start the dedicated air supply fan) to form a positive pressure barrier, and activate the dust exhaust fan in that area. This mode ensures absolute priority for safety objectives.

[0100] 2. Nighttime Ventilation and Cooling Storage Mode: Judgment conditions: During non-working hours (e.g., midnight to early morning), T_out < T_u, and T_w is higher than the preset nighttime setting. Actions: Start some mechanical supply and exhaust fans and appropriately open roof ventilators to utilize the low-temperature nighttime air to "wash" and cool the entire factory structure, storing cooling capacity to reduce the air conditioning load for the next day. This feature fully utilizes time differences and natural cooling sources. It extends the utilization period of natural cooling sources, extending the energy-saving strategy from daytime to the entire day. Actively utilizing time differences to transfer load and reduce the air conditioning start-up load for the next day is an effective means of achieving deep energy savings.

[0101] 3. Daytime Mode Decision (Working Hours): When the above modes are not met, the system enters the daytime mode decision tree based on temperature and enthalpy.

[0102] Natural ventilation-dominated mode: Judgment conditions: T_out is lower than the first set temperature threshold (e.g., 18℃) and ΔT > the first temperature difference threshold (e.g., 8℃). Actions: Turn off or minimize air conditioning cooling / heating; dynamically calculate and adjust the optimal opening of the roof ventilator based on the ΔT value using a lookup table method or PI control algorithm; simultaneously, some exhaust fans can be activated to assist, forming a combined heat dissipation flow field dominated by thermal pressure ventilation and supplemented by mechanical exhaust. This mode maximizes the use of free cooling under suitable weather conditions.

[0103] Air conditioning and ventilation coordinated mode: Judgment condition: T_out is between the first and second set temperature thresholds (e.g., 28℃), or ΔT is too small to drive effective thermal pressure ventilation. Action: Activate the stratified air conditioning system to ensure the set temperature of the lower working area (T_w); simultaneously, based on the upper temperature T_u, dynamically adjust the opening of the roof ventilator or the frequency of the mechanical exhaust fan. The purpose is to systematically and supplementarily exhaust the upper residual heat that the air conditioning system has failed to handle, preventing excessive heat accumulation. This mode embodies the coordinated principle of "air conditioning maintaining the lower limit, ventilation exhausting the upper limit."

[0104] Air-conditioned Dominated Closed Mode: Judgment Criteria: T_out > Second Set Temperature Threshold, or H_out > Indoor Set Air Enthalpy (Introducing fresh air is uneconomical in this case). Actions: Close roof ventilators to minimize building envelope infiltration; rely entirely on the air conditioning system to handle indoor cooling load; mechanical ventilation maintains only the minimum necessary fresh air exchange rate. This mode aims to prevent the intrusion of high-enthalpy outdoor air under extreme weather conditions.

[0105] Example 2: Enhanced Adaptive Cooperative Control System. Based on Example 1, this example introduces additional technical features such as dust control, load feedforward, and parameter self-optimization, forming a more comprehensive and intelligent solution.

[0106] 1. System Enhancement Deployment

[0107] Add dust concentration sensors (102): Install one laser dust concentration detector in the coal mill level (elevation +6.3m) of the turbine hall and in the zero-meter feedwater pump area, and connect the signal to the PLC.

[0108] Accessing DCS load signals: The "generator active power (MW)" and "electric feedwater pump operating status" signals are read in real time from the power plant's DCS system via the OPC communication protocol, serving as the basis for estimating the heat load Q_equip of the main equipment in the plant. Settings: Q_equip is 100% at full load (600MW), 60% at 50% load, and 20% during shutdown.

[0109] Upgrade control software: Add a "Data Analysis and Optimization" service program to the monitoring server (109), which runs an optimization algorithm once a week.

[0110] 2. Enhance the implementation of control methods

[0111] Dust Priority Control (New Mode P): In the mode judgment logic of step S200, this mode is given the highest priority. If any dust sensor reading exceeds 8 mg / m³, the current mode is immediately interrupted, and mode P is forcibly entered. The instructions for mode P are: ① Immediately increase the frequency of the two exhaust fans above the dust-exceeding area to 50 Hz. ② Switch the adjacent AHU to "Fresh Air" mode, increasing the fan frequency to 45 Hz to create local positive pressure and dilution airflow. After 10 minutes, if the concentration drops below the limit, the original temperature control mode is automatically restored.

[0112] Load feedforward regulation: When generating mode commands in step S200, Q_equip is introduced as a feedforward correction factor. For example, in mode B, the base exhaust fan frequency is 30Hz. When the current Q_equip is 80%, the frequency correction is `30Hz (1 + 0.5(0.8-0.5)) = 34.5Hz`, where 0.5 is the assumed average load rate. This allows the system to proactively enhance ventilation when the load increases, improving response speed. The system obtains operating condition signals (such as generator load, main auxiliary machine operating current, or status) reflecting the heat load (Q_equip) of the main equipment in the plant from the distributed control system (DCS). When selecting or switching operating modes, Q_equip is used as a feedforward input to predictively adjust the base frequency setpoint of the mechanical supply and exhaust fans or the aggressiveness of the ventilation strategy. This upgrades the control from a simple "feedback response" to "feedforward-feedback composite control". By predicting the changing trends of the main heat sources in the plant, the system can adjust the ventilation volume earlier and more smoothly, reduce control lag, improve environmental stability, and potentially avoid frequent mode switching caused by sudden load changes.

[0113] Parameter self-optimization (new step S400 refinement): The data analysis service program performs the following operations weekly:

[0114] 1. Extract all data points from the past week that meet the conditions of 16℃≤T_out≤20℃ and the system is running in mode A.

[0115] 2. Analyze the minimum average opening of the roof ventilator required to maintain T_w≤26℃ at these points.

[0116] 3. If the average opening degree is consistently lower than the preset opening degree value of ΔT in the strategy library by more than 10%, the user will be prompted or the opening degree value of ΔT in the strategy library will be automatically reduced by 5%. A similar method can be used for temperature thresholds (such as the first threshold of 18℃), by analyzing the comprehensive energy consumption 24 hours before and after the mode switch to evaluate its rationality and suggest adjustments.

[0117] Functions and Effects: Building upon the energy-saving features of Example 1, this embodiment significantly improves system safety (rapid dust response) and the predictability and stability of control (load feedforward). Simultaneously, the self-optimization function enables the system to adapt to changes in efficiency or heat load caused by local modifications after long-term unit operation, ensuring that the collaborative control strategy remains in an optimal state over the long term and reducing the labor costs of later maintenance and adjustments. For example, when unit efficiency improves and heat generation decreases after maintenance, the system can automatically reduce ventilation intensity to avoid heat waste caused by excessive ventilation.

[0118] In the description of embodiments of the present invention, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0119] In the description of embodiments of the present invention, the term "and / or" is used only to describe the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " generally indicates that the preceding and following associated objects are in an "or" relationship.

[0120] 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 control system for the ventilation and air conditioning system of the main building of a thermal power plant, characterized in that, It includes a data acquisition layer, a control layer, and an execution layer; The data acquisition layer collects all the key parameters required for control decision-making in real time through a sensor network. The control layer includes a strategy analysis and decision module and a control instruction execution module. The strategy analysis and decision module contains a multi-mode collaborative operation strategy library, receives data from the sensor network, judges the stored operation modes based on priority and conditions, and outputs the current optimal system operation mode instruction and specific control settings for each execution device. The control command execution module is used to convert the commands output by the strategy analysis and decision-making module into recognizable signals for each execution device controller, and then send them out for execution. The execution layer consists of controlled execution devices used to achieve full-spectrum environmental regulation, ranging from natural ventilation to mechanical refrigeration. The implementing equipment includes a roof natural ventilator, a supply fan, an exhaust fan, and a stratified air conditioning system; The data acquisition layer includes an environmental parameter acquisition unit, a meteorological parameter acquisition unit, and an equipment status and load acquisition unit; The environmental parameter acquisition unit includes: Lower working area temperature and humidity sensors: located in the working area, used to monitor the core thermal comfort parameters of temperature T_w and relative humidity RH_w in the personnel activity area; Upper space temperature sensor: Located in the area where hot air gathers, used to monitor the upper space temperature T_u, and calculate the temperature difference ΔT using T_u and T_w; Dust concentration sensor in the work area: placed near the coal mill layer, coal conveyor belt or main inspection passage, to monitor the concentration of inhalable particulate matter C_d in the air; The meteorological parameter acquisition unit is installed on the roof of the main plant or in an unobstructed area, and at least collects the outdoor dry-bulb temperature T_out and relative humidity to obtain the enthalpy value H_out; The equipment status and load acquisition unit obtains data through the power plant's distributed control system or equipment controller to estimate the real-time equipment heat load Q_equip in the plant. The equipment heat load Q_equip is used as a feedforward input to predictively adjust the base frequency setpoints of the supply fan and exhaust fan or the aggressiveness of the ventilation strategy when selecting or switching operating modes. The control layer also includes a data storage and self-optimization module, which continuously stores system operation data and energy consumption data, and periodically runs optimization algorithms to compare actual energy consumption with theoretical optimal values ​​or historical best values ​​under different external conditions, fine-tunes key threshold parameters in the strategy library, and realizes the system's incremental self-optimization.

2. The control system for the ventilation and air conditioning system of the main building of a thermal power plant according to claim 1, characterized in that, The equipment status and load acquisition unit obtains data from the power plant's distributed control system or equipment controller, including the real-time opening degree of the roof natural ventilator, the operating frequency and start / stop status of the supply and exhaust fans, and the operating mode and set parameters of the air conditioning unit.

3. A control method for the ventilation and air conditioning system of the main building of a thermal power plant, employing the system described in any one of claims 1 to 2, characterized in that, include: Step 100, Real-time Data Acquisition and Fusion: Synchronously acquire all sensor data and device status, and perform validity verification and data smoothing processing; Step 200, Intelligent decision-making for operating mode: The multi-mode collaborative operation strategy library makes a step-by-step and priority judgment. The multi-mode collaborative operation strategy library defines several preset joint operation modes. Each mode corresponds to a control logic for the collaborative work of each execution device. The control switching of the mode is controlled according to the parameters T_out, H_out, T_u, T_w, ΔT, C_d and Q_equip. Step 300, Control command generation and issuance: Based on the selected mode, generate a set of control commands containing the target status of each device and issue them to the field execution devices; Step 400, Monitoring and Adaptive Optimization: Monitor the execution effect of instructions and energy consumption data, and automatically or semi-automatically optimize the threshold parameters in the strategy library through long-term data learning.

4. The control method for the ventilation and air conditioning system of the main building of a thermal power plant according to claim 3, characterized in that, The preset joint operation modes include: Dust control priority mode, judgment condition: dust concentration in any work area exceeds the safety limit, action: regardless of the current temperature control mode, immediately enhance the lower air supply in the affected area to form a positive pressure barrier, and activate the dust exhaust fan in that area. Nighttime ventilation and cold storage mode: Judgment conditions: During non-working hours, the outdoor dry-bulb temperature T_out < the upper space temperature T_u, and the working area temperature T_w is higher than the preset nighttime setting value. Action: Start some supply fans and exhaust fans, and open the roof natural ventilators appropriately to use the low-temperature nighttime air to cool the entire factory structure and store cold energy to reduce the air conditioning load for the next day. Natural ventilation dominant mode: Judgment conditions: The outdoor dry bulb temperature T_out is lower than the first set temperature threshold and ΔT > the first temperature difference threshold. Actions: Turn off or minimize the air conditioning cooling / heating; Based on the ΔT value, dynamically calculate and adjust the optimal opening of the roof natural ventilator through a lookup table method or PI control algorithm; At the same time, start some exhaust fans to form a combined heat dissipation flow field with thermal pressure ventilation as the main method and mechanical exhaust as the auxiliary method. Air conditioning and ventilation coordinated mode: Judgment conditions: The outdoor dry bulb temperature T_out is between the first and second set temperature thresholds, or ΔT is too small to drive effective thermal pressure ventilation. Action: Start the stratified air conditioning system to ensure the set temperature T_w of the lower working area; at the same time, according to the upper space temperature T_u, dynamically adjust the opening of the roof natural ventilator or the frequency of the exhaust fan to orderly and auxiliaryly discharge the upper residual heat that the air conditioning system could not handle, and prevent excessive heat accumulation. Air conditioning-dominated closed mode: Judgment conditions: outdoor dry bulb temperature T_out > second set temperature threshold, or enthalpy H_out > indoor set air enthalpy. Actions: shut down roof natural ventilators to minimize infiltration into the building envelope; rely entirely on the air conditioning system to bear the indoor cooling load; mechanical ventilation only maintains the minimum necessary number of fresh air exchanges.

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