An adaptive energy-saving control method and system for heating and ventilation system of a thermal power plant

Abstract

This invention discloses an adaptive energy-saving control method and system for HVAC systems in thermal power plants, relating to the field of intelligent control technology for HVAC systems in thermal power plants. The method includes: real-time acquisition of operating parameters of the HVAC system; feedforward calculation of the plant's cooling load at future times based on the operating parameters; automatic switching between a first operating mode and a second operating mode based on a comparison of outdoor and indoor air enthalpy values ​​and outdoor temperature; in any mode, calculating a condensation risk coefficient based on the difference between equipment surface temperature and air dew point temperature, and implementing anti-condensation intervention when the coefficient is below a warning threshold; in the second operating mode, utilizing low-grade waste heat from the power plant to reheat the dehumidified air with equal humidity, raising the supply air temperature to a safe range above the dew point temperature. This invention can utilize free cold sources and low-grade waste heat to eliminate heat and cold offsetting, achieving proactive anti-condensation and load feedforward control, significantly reducing HVAC system energy consumption and ensuring the safety of electrical equipment.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology for heating, ventilation, and air conditioning (HVAC) systems in thermal power plants, specifically to an adaptive energy-saving control method and system for HVAC systems in thermal power plants. Background Technology

[0002] The heating, ventilation, and air conditioning (HVAC) system of a thermal power plant undertakes important tasks such as ventilation and cooling of the plant, temperature and humidity control of electrical equipment rooms, and environmental protection for personnel inside the plant. The electrical equipment in the power plant is densely arranged and has a large overall heat dissipation. Key electrical equipment such as frequency converter cabinets and DCS control cabinets are extremely sensitive to surface condensation. Condensation can directly threaten the insulation safety of the equipment and even cause serious accidents such as unit tripping. Currently, most mainstream HVAC systems in the industry adopt a fixed threshold single feedback control mode. This operating mode has many problems that urgently need to be solved. The system cannot comprehensively judge the availability of free cooling sources by combining outdoor meteorological conditions. During the transition season and winter when the outdoor air has natural cooling conditions, mechanical refrigeration equipment continues to run, resulting in a large amount of outdoor cooling source being wasted. In summer, in order to meet the air dehumidification needs, the air is deeply cooled, and then the supply air temperature is increased by electric reheaters, resulting in a significant cooling and heating offsetting phenomenon. At the same time, a large amount of low-grade waste heat generated normally in the plant cannot be connected to the HVAC system for utilization and can only be directly discharged, resulting in low overall energy utilization. In addition, the existing control method can only take remedial measures passively after condensation occurs, without real-time monitoring of equipment surface temperature and prediction of condensation risk, leaving electrical equipment with long-term safety hazards. Furthermore, the traditional control logic does not link with generator set operating data, and cannot predict changes in plant heat and humidity load in advance. The adjustment action has a significant lag, resulting in frequent fluctuations in indoor heat and humidity environment, which makes it difficult to meet the comprehensive use requirements of thermal power plant equipment safety, environmental stability and energy-saving operation. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide an adaptive energy-saving control method and system for HVAC systems in thermal power plants, which solves the problems of low utilization rate of free cold sources, heat and cold offsetting, high risk of condensation, and control lag in existing systems.

[0004] To achieve the above objectives, the embodiments of this invention provide the following technical solutions:

[0005] This application provides an adaptive energy-saving control method for a heating, ventilation, and air conditioning (HVAC) system in a thermal power plant, comprising the following steps: S1, real-time acquisition of operating parameters of the HVAC system, including outdoor air temperature, outdoor relative humidity, indoor air temperature, indoor relative humidity, equipment surface temperature, and generator load prediction; S2, feedforward calculation of the plant's cooling load at future times based on the generator load prediction; S3, automatic mode switching between a first operating mode and a second operating mode based on the comparison between outdoor and indoor air enthalpy and the outdoor air temperature; S4, in any operating mode, calculation of a condensation risk coefficient based on the difference between equipment surface temperature and indoor air dew point temperature, and execution of anti-condensation intervention when the condensation risk coefficient is lower than a warning threshold; S5, when the HVAC system is in the second operating mode, utilizing the low-grade waste heat of the power plant, a waste heat reheat module located at the rear end of the air conditioning unit's surface cooler is used to perform isohumid reheating of the dehumidified air, raising the supply air temperature to a safe range above the dew point temperature.

[0006] Furthermore, the specific criteria for mode switching in S3 are as follows: The outdoor air enthalpy is calculated using the air enthalpy calculation formula based on the collected outdoor air temperature and relative humidity; the indoor air enthalpy is calculated using the air enthalpy calculation formula based on the collected indoor air temperature and relative humidity; the expression for the air enthalpy calculation formula is: ,in This is the enthalpy of air. The corresponding air temperature, The corresponding air humidity is determined by the corresponding air temperature and the corresponding relative humidity. When the outdoor air enthalpy is less than the indoor air enthalpy and the outdoor air temperature is less than or equal to the preset switching threshold, it is determined that an outdoor cold source can be used, and the HVAC system switches to the first operating mode, that is, the refrigeration unit is turned off, the fresh air valve is opened to full opening, and the return air valve is closed; otherwise, the system switches to the second operating mode, that is, the refrigeration unit is started or maintained, the fresh air valve is adjusted to the minimum allowable opening, and the return air valve is opened.

[0007] Furthermore, S4 further includes: calculating the indoor air dew point temperature based on the indoor air temperature and humidity, using the following formula: ,in, , , , Indoor air temperature, in °C; The relative humidity of indoor air is expressed as a percentage (%). The indoor air dew point temperature is used; the surface temperature of the equipment is obtained through an infrared temperature sensor; a condensation risk coefficient is calculated based on the equipment surface temperature and the indoor air dew point temperature; according to the numerical range of the condensation risk coefficient, the status is determined as safe, warning, or dangerous, and corresponding anti-condensation intervention strategies are triggered.

[0008] Furthermore, the anti-condensation intervention strategy specifically includes: in the first operating mode, adjusting the opening ratio of the fresh air valve and the return air valve to introduce some hot return air to increase the supply air temperature, while reducing the frequency of the supply fan to reduce the supply air speed; in the second operating mode, prioritizing the use of the waste heat reheat module to increase the supply air temperature, and activating the backup low-power electric reheater when the waste heat is insufficient.

[0009] Furthermore, in step S5, the target supply air temperature is set as the sum of the indoor air dew point temperature and a preset safety margin. The flow rate of hot water entering the waste heat exchange coil is controlled via PID regulation to ensure that the actual supply air temperature is controlled within a preset deviation range of the target supply air temperature. The expression for the target supply air temperature is: ,in, For the target supply air temperature, This refers to the indoor air dew point temperature. This is a preset safety margin.

[0010] Furthermore, in S2, the plant's cooling load at future times is calculated using a feedforward method, specifically expressed as follows: ,in, For sensible heat load, the calculation expression is: , The heat dissipation coefficient of the corresponding device. The corresponding heat transfer coefficient of the building envelope, This represents the predicted load value for the generator set. Outdoor air temperature Set the indoor temperature. The latent heat load is calculated using the following expression: , For air supply volume, The humidity level of indoor air. The moisture content of the supplied air. It is the latent heat of vaporization of water.

[0011] Furthermore, S4 also includes variable air volume adjustment logic, that is, real-time monitoring of indoor carbon dioxide concentration. When the indoor carbon dioxide concentration exceeds the set upper limit, the fresh air volume and total air supply volume are increased first to dilute it. After the indoor carbon dioxide concentration drops below the target value, the air supply volume is adjusted for energy saving according to the temperature deviation.

[0012] Accordingly, this application also provides an adaptive energy-saving control system for a thermal power plant's HVAC system, comprising: a data acquisition unit for real-time acquisition of operating parameters of the HVAC system, including outdoor air temperature, outdoor relative humidity, indoor air temperature, indoor relative humidity, equipment surface temperature, and generator load prediction values; a load prediction unit connected to the output of the data acquisition unit for receiving the generator load prediction values ​​and performing feedforward calculations on the plant's cooling load at future times based on the generator load prediction values; and a mode switching unit connected to the outputs of the data acquisition unit and the load prediction unit, respectively, for calculating the plant's cooling load based on a comparison of outdoor and indoor air enthalpy values, and in conjunction with outdoor... The air temperature automatically switches between the first and second operating modes. The anti-condensation control unit is connected to the outputs of the data acquisition unit and the mode switching unit, respectively. It is used to calculate the condensation risk coefficient based on the difference between the equipment surface temperature and the indoor air dew point temperature in any operating mode. When the condensation risk coefficient is lower than the warning threshold, anti-condensation intervention is performed. The waste heat utilization unit is connected to the outputs of the mode switching unit and the anti-condensation control unit, respectively. When the HVAC system is in the second operating mode, it uses the low-grade waste heat from the power plant to perform isohumid reheating on the dehumidified air through the waste heat reheat module set at the rear end of the air conditioning unit's surface cooler, raising the supply air temperature to a safe range above the dew point temperature.

[0013] Furthermore, the anti-condensation control unit includes: a dew point temperature calculation subunit, used to calculate the indoor air dew point temperature based on the indoor air temperature and relative humidity; a data receiving module, used to receive the equipment surface temperature collected by the infrared temperature sensor; a risk coefficient calculation subunit, used to calculate the condensation risk coefficient and determine the safe state, warning state, or dangerous state based on the numerical range; and an intervention strategy execution subunit, used to execute corresponding anti-condensation interventions according to the current operating mode, wherein: in the first operating mode, the opening ratio of the fresh air valve and the return air valve is adjusted and the frequency of the supply fan is reduced; in the second operating mode, the waste heat utilization unit is preferentially used to increase the supply air temperature, and when the waste heat is insufficient, the backup low-power electric reheater is activated.

[0014] The beneficial effects of this invention are as follows: By constructing a closed-loop adaptive control system with multi-data fusion and multi-objective collaboration, it can fully explore and utilize free outdoor cold sources and low-grade waste heat in the plant area, fundamentally reducing ineffective energy consumption and heat-cooling offsetting problems in the HVAC system. At the same time, it takes equipment anti-condensation as the core control objective, realizing the transformation from passively dealing with condensation problems to actively predicting risks, comprehensively ensuring the operational safety of electrical equipment in the plant area. Relying on generator load prediction to achieve feedforward control, it effectively eliminates the lag of traditional control methods, allowing the indoor thermal and humid environment to remain stable for a long time. The entire control logic takes into account multiple core needs such as equipment safety, personnel comfort, and energy saving and consumption reduction, and can adapt to various operating conditions under different climate conditions and different unit loads throughout the year in thermal power plants, greatly improving the overall operational reliability and comprehensive operational efficiency of the system. Attached Figure Description

[0015] Figure 1 A flowchart illustrating an adaptive energy-saving control method for a heating, ventilation, and air conditioning system in a thermal power plant, provided as an embodiment of this application;

[0016] Figure 2 This is a schematic diagram of the structure of an adaptive energy-saving control system for a heating, ventilation, and air conditioning system in a thermal power plant, provided as an embodiment of this application. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0018] In this invention, the terms "system" and "network" are used interchangeably. "Multiple" refers to two or more; therefore, in this invention, "multiple" can also be understood as "at least two." "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / ", unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, it should be understood that in the description of this invention, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0019] Example 1:

[0020] like Figure 1As shown in the embodiment of this application, an adaptive energy-saving control method for the heating, ventilation, and air conditioning (HVAC) system of a thermal power plant is provided, including the following steps: S1, real-time acquisition of the operating parameters of the HVAC system, including outdoor air temperature, outdoor relative humidity, indoor air temperature, indoor relative humidity, equipment surface temperature, and generator load prediction; S2, based on the generator load prediction, feedforward calculation of the plant's cooling load at future times; S3, based on the comparison result of outdoor air enthalpy and indoor air enthalpy, and combined with outdoor air temperature, automatic mode switching between a first operating mode and a second operating mode; S4, in any operating mode, calculating the condensation risk coefficient based on the difference between equipment surface temperature and indoor air dew point temperature, and executing anti-condensation intervention when the condensation risk coefficient is lower than the warning threshold; S5, when the HVAC system is in the second operating mode, utilizing the low-grade waste heat of the power plant, through a waste heat reheat module installed at the rear end of the air conditioning unit's surface cooler, performing isohumid reheating of the dehumidified air to raise the supply air temperature to a safe range above the dew point temperature.

[0021] In another possible embodiment, the HVAC controller first continuously collects comprehensive operating parameters according to a preset adjustable acquisition cycle. Outdoor environmental parameters are collected by outdoor temperature and humidity sensors located in the shaded areas of the plant's exterior walls; indoor environmental parameters are collected by indoor temperature and humidity sensors distributed in areas such as the electronic equipment room, power distribution room, and turbine room; equipment safety parameters are collected by infrared non-contact temperature sensors equipped with self-cleaning air curtains, capturing the surface temperature of critical electrical equipment; and indoor air quality parameters are collected by carbon dioxide concentration sensors installed in the air conditioning return air main and return air vents in various areas. Simultaneously, the controller reads the current load of the generator sets and the load forecast for the next 1 to 3 hours from the power plant's DCS system via a communication interface, and also collects the data sent by the air conditioning system. All collected data, including return air temperature, air volume, and unit operating status, are cached within the controller. The controller then uses its built-in calculation model, combined with the generator load forecast curve and outdoor weather trends, to calculate the sensible and latent heat loads of the plant. These are then superimposed to obtain the overall cooling load of the plant. Pre-adjustment is achieved based on 1-3 hour load forecasts, overcoming the limitations of traditional passive feedback control. The controller then retrieves real-time temperature and humidity data to calculate indoor and outdoor air enthalpy values. Combined with the real-time outdoor temperature, a dual-condition judgment is performed. Based on the judgment result, the system is switched to either all-air energy-saving ventilation mode (first operating mode) or mechanical refrigeration plus recirculating air mode (second operating mode), simultaneously controlling the refrigeration unit, fresh air valve, and return air. Once the valve completes its linkage action, the controller prioritizes adjusting the supply air volume and fresh air volume based on the indoor carbon dioxide concentration to ensure indoor air quality in any system operating mode. Based on this, it performs energy-saving air volume adjustments in conjunction with indoor temperature, while continuously calculating the indoor air dew point temperature and condensation risk factor. According to the risk level and the current operating mode, it takes corresponding anti-condensation intervention actions. Subsequently, when the system is in mechanical refrigeration plus circulating air mode, the controller activates the waste heat reheat process, introducing low-grade waste heat, such as condensate from the plant turbine, into the waste heat exchange coil at the rear of the air conditioning unit's surface cooler. This performs isohumid reheating of the dehumidified low-temperature air. Only when the waste heat supply is insufficient or interrupted is a backup low-power electric reheater activated as a supplement. The entire process is repeated cyclically. The system operates adaptively under all conditions. During transitional seasons when outdoor temperatures are suitable and the outdoor air enthalpy is significantly lower than the indoor air enthalpy, the system automatically switches to an all-air energy-saving ventilation mode (Mode 1). The refrigeration unit completely shuts down, relying on outdoor fresh air to remove heat from the factory equipment. At this time, the equipment surface temperature is much higher than the indoor dew point temperature, and the condensation risk factor is within a safe range (≥3℃). There is no need to activate anti-condensation intervention or heating equipment; the system can maintain stable operation simply by maintaining the frequency converter operation of the fan. In the high-temperature and high-humidity environment of summer, when the outdoor air enthalpy is higher than the indoor air enthalpy, the system switches to a mechanical refrigeration plus circulating air mode (Mode 2). The fresh air valve maintains a minimum sanitary opening, and the controller continuously monitors the dew point temperature and equipment surface temperature. Once it detects that the condensation safety margin is narrowing, the system will activate the ventilation mode.The system automatically activates the waste heat reheat module to raise the supply air temperature, bringing the dehumidified, low-temperature air to a safe temperature range. The backup electric reheater is not used throughout the process. The refrigeration unit also benefits from the increased supply air temperature, resulting in optimized energy efficiency. Even in extremely cold winter conditions, although the outdoor enthalpy and temperature meet the criteria for all-air ventilation, the indoor carbon dioxide concentration is near its upper limit, and the extremely cold fresh air can cause a sudden drop in equipment surface temperature. Therefore, the system does not fully open the fresh air valve; instead, it adjusts the mixing ratio of fresh and return air and reduces the fan speed. While utilizing the free outdoor cooling source, it avoids excessively cold equipment and discomfort for personnel. The entire process relies on the air system for condensation control.

[0022] By constructing a closed-loop adaptive control system that integrates multiple data and coordinates multiple objectives, it can fully explore and utilize free outdoor cold sources and low-grade waste heat in the plant area, fundamentally reducing ineffective energy consumption and heat-cooling offsetting problems in the HVAC system. At the same time, it takes equipment anti-condensation as the core control objective, realizing the transformation from passively dealing with condensation problems to proactively predicting risks, comprehensively ensuring the operational safety of electrical equipment in the plant area. Relying on generator load forecasting to achieve feedforward control, it effectively eliminates the lag of traditional control methods, keeping the indoor thermal and humidity environment stable for a long time. The entire control logic takes into account multiple core needs such as equipment safety, personnel comfort, and energy saving and consumption reduction, and can adapt to various operating conditions under different climate conditions and unit loads throughout the year in thermal power plants, significantly improving the overall operational reliability and comprehensive operational efficiency of the system.

[0023] In this embodiment, the specific criteria for mode switching in S3 are as follows: The outdoor air enthalpy is calculated using the air enthalpy calculation formula based on the collected outdoor air temperature and relative humidity; the indoor air enthalpy is calculated using the air enthalpy calculation formula based on the collected indoor air temperature and relative humidity; the expression for the air enthalpy calculation formula is: ,in This is the enthalpy of air. The corresponding air temperature, The corresponding air humidity is determined by the corresponding air temperature and the corresponding relative humidity. When the outdoor air enthalpy is less than the indoor air enthalpy and the outdoor air temperature is less than or equal to the preset switching threshold, it is determined that an outdoor cold source can be used, and the HVAC system switches to the first operating mode, that is, the refrigeration unit is turned off, the fresh air valve is opened to full opening, and the return air valve is closed; otherwise, the system switches to the second operating mode, that is, the refrigeration unit is started or maintained, the fresh air valve is adjusted to the minimum allowable opening, and the return air valve is opened.

[0024] In another possible embodiment, the controller first retrieves the real-time indoor and outdoor dry-bulb temperatures and relative humidity, and calculates the outdoor and indoor air enthalpy values ​​respectively according to a unified air enthalpy calculation formula. The air humidity in the formula is derived from the temperature and relative humidity of the corresponding area. The outdoor temperature switching threshold is a limited value that can be flexibly adjusted according to the regional climate. Next, the controller synchronously compares the outdoor air enthalpy, indoor air enthalpy, and real-time outdoor temperature, performing a dual-condition judgment. Then, when the outdoor air enthalpy is less than the indoor air enthalpy and the outdoor temperature does not exceed the preset switching threshold, the system determines that the outdoor air meets the conditions for free cooling, and immediately issues a shutdown command to the refrigeration unit, while simultaneously adjusting the fresh air valve to full opening. With the status and return air valve adjusted to the fully closed position, the system officially enters the all-air energy-saving ventilation mode (first operating mode). Finally, when the outdoor air enthalpy is greater than or equal to the indoor air enthalpy, or the outdoor temperature exceeds the preset switching threshold, the system determines that it cannot meet the cooling demand by relying on outdoor fresh air. It then starts or maintains the continuous operation of the refrigeration unit, adjusts the fresh air valve to the minimum opening to meet the hygiene requirements of personnel, and opens the return air valve to reduce the cooling load by circulating indoor air. The system then enters the mechanical refrigeration plus circulating air mode (second operating mode). In the transitional season with suitable climate, this dual judgment rule can accurately identify the free cooling source window period and orderly complete the linkage switching of the refrigeration unit and air valve to ensure that the air system operating condition is always stable.

[0025] By employing a dual-judgment logic that combines air enthalpy with outdoor temperature, the system can simultaneously consider the impact of temperature and humidity on HVAC loads, effectively avoiding the problem of incorrect mode switching caused by a single temperature judgment, significantly improving the accuracy of free cold source identification, and clarifying the standard operating logic of refrigeration units, fresh air valves, and return air valves under different operating modes. This ensures more coordinated cooperation among the various components of the air system, maintains stable system operation, and ensures that the minimum fresh air opening set in cooling mode can continuously guarantee the basic ventilation needs of personnel in the plant, achieving a balance between energy-saving operation and indoor hygiene.

[0026] In this embodiment, step S4 further includes: calculating the indoor air dew point temperature based on the indoor air temperature and humidity, using the following formula: ,in, , , , Indoor air temperature, in °C; The relative humidity of indoor air is expressed as a percentage (%). The indoor air dew point temperature is used; the surface temperature of the equipment is obtained through an infrared temperature sensor; a condensation risk coefficient is calculated based on the equipment surface temperature and the indoor air dew point temperature; according to the numerical range of the condensation risk coefficient, the status is determined as safe, warning, or dangerous, and corresponding anti-condensation intervention strategies are triggered.

[0027] In another possible embodiment, the controller first retrieves real-time indoor air temperature and relative humidity data, and continuously calculates the indoor air dew point temperature using a standardized fitting formula. This formula incorporates fixed fitting coefficients to ensure the accuracy of the dew point temperature calculation. The dew point temperature value is updated in real-time according to changes in indoor temperature and humidity. Next, infrared non-contact temperature sensors deployed on the outside of the inverter cabinet, DCS control cabinet, and distribution panel continuously collect the surface temperature of the equipment. Self-cleaning air curtains at the sensor front end prevent dust from adhering to the sensor probe surface, avoiding dust interference with temperature measurement accuracy and ensuring the accuracy and validity of the temperature data. Finally, the controller subtracts the indoor dew point temperature from the measured surface temperature of the equipment. Temperature is used to calculate the condensation risk coefficient, and three risk levels are divided according to the range of the risk coefficient. When the risk coefficient is greater than 3℃, it is judged as a safe state, which means that there is no risk of condensation on the equipment surface and no intervention is required. When the risk coefficient is between 1℃ and 3℃, it is judged as a warning state, which means that there is a potential risk of condensation on the equipment and preventive intervention measures need to be initiated. Finally, when the risk coefficient is less than or equal to 1℃, it is judged as a dangerous state, which means that condensation is about to occur or has already occurred and strong intervention measures need to be initiated immediately. In the high temperature and high humidity environment in summer, this judgment process can accurately identify the condensation risk caused by low temperature air supply and provide reliable data support for subsequent intervention actions.

[0028] By calculating the indoor air dew point temperature and combining it with infrared sensors to directly collect the equipment surface temperature, the actual condensation conditions on site can be accurately reproduced, making the risk assessment results more consistent with the actual operating conditions of the power plant. The three-level risk classification can match different handling methods according to the severity of the hidden dangers, which can not only protect the insulation safety of electrical equipment in all aspects and prevent equipment operation failures caused by condensation, but also avoid unnecessary heating and ventilation operations, effectively reducing excess energy consumption.

[0029] In this embodiment of the application, the anti-condensation intervention strategy specifically includes: in the first operating mode, adjusting the opening ratio of the fresh air valve and the return air valve to introduce some hot return air to increase the supply air temperature, while reducing the frequency of the supply fan to reduce the supply air speed; in the second operating mode, prioritizing the use of the waste heat reheat module to increase the supply air temperature, and when the waste heat is insufficient, activating the backup low-power electric reheater.

[0030] In another possible embodiment, the system first identifies the current operating mode and condensation risk level. Then, if the system is in the all-air energy-saving ventilation mode (first operating mode) and triggers a warning or dangerous state, the system will not start any heating equipment. Instead, it will adjust the opening ratio of the fresh air valve and the return air valve to introduce some warmer indoor return air to mix with the outdoor fresh air, thereby increasing the overall supply air temperature. At the same time, it will adjust the operating frequency of the variable frequency fan to reduce the supply air velocity and weaken the direct impact of the low-temperature airflow on the surface of electrical equipment. This eliminates the risk of condensation from both the air temperature and air velocity perspectives. Then, if the system is in the mechanical refrigeration plus circulating air mode (second operating mode), the system will proceed as follows: Furthermore, when a warning or dangerous state is triggered, the system will prioritize increasing the opening of the waste heat hot water pipeline valves, relying on the low-grade waste heat in the plant area to raise the supply air temperature to avoid the risk of condensation. Finally, only when the waste heat supply is interrupted or the waste heat flow or temperature cannot meet the heating requirements will the system start the low-power electric reheater as a backup for supplementary heating. In extremely cold winter environments, when the system is in ventilation mode, it relies on adjusting the fresh air and return air ratio and reducing the air velocity to avoid low-temperature condensation and equipment overcooling problems throughout the process, without using heating equipment, thus maximizing the utilization value of the free cold source. In summer operating conditions, the system prioritizes using waste heat to complete the heating, significantly reducing the frequency of starting and stopping the electric reheater.

[0031] By relying on the air system to regulate and prevent condensation in the all-air ventilation mode (first operating mode), the energy-saving advantage of the free outdoor cold source is fully preserved. In the mechanical refrigeration plus circulating air mode (second operating mode), the waste heat resources of the plant area are used first, which greatly reduces the start-up time of electric heating equipment. All kinds of intervention actions are deeply integrated with the original operating mode. On the basis of effectively eliminating the risk of condensation and ensuring equipment safety, the energy-saving operation effect of the system is maintained to the maximum extent.

[0032] In this embodiment, the target supply air temperature in step S5 is set as the sum of the indoor air dew point temperature and a preset safety margin. The flow rate of hot water entering the waste heat exchange coil is controlled by PID regulation to ensure that the actual supply air temperature is controlled within a preset deviation range of the target supply air temperature. The expression for the target supply air temperature is: ,in, For the target supply air temperature, This refers to the indoor air dew point temperature. This is a preset safety margin.

[0033] In another possible embodiment, the controller first calculates the dynamic target supply air temperature based on the real-time calculated indoor dew point temperature, adding a preset safety margin of 2-3℃. The safety margin ensures that the supply air temperature is always higher than the air dew point temperature, reserving sufficient safety margin to prevent condensation. When the indoor dew point temperature changes, the target supply air temperature will also be dynamically updated synchronously. Then, the controller collects the actual supply air temperature at the air outlet of the air conditioning unit in real time. The waste heat exchange coil is fixedly installed at the rear end of the air conditioning unit's surface cooler. The low-temperature air after dehumidification will flow through the heat exchange coil to complete the isohumidity heating. Then, the controller compares the measured supply air temperature with the dynamic target supply air temperature and continuously adjusts the opening of the electric proportional regulating valve on the waste heat hot water pipeline through a PID closed-loop algorithm to accurately control the flow rate of waste heat hot water entering the heat exchange coil. Finally, the supply air temperature is kept stable within the target range for a long time. In the high temperature and high humidity conditions of summer, this set of adjustment logic can accurately raise the temperature of the low-temperature air after dehumidification by the surface cooler to the safe range, which not only completely eliminates the risk of condensation, but also makes full use of the low-grade waste heat of the plant area.

[0034] The dynamically updated target supply air temperature can adapt to real-time changes in indoor temperature and humidity, always maintaining a stable and reasonable safety margin against condensation. This eliminates the risk of condensation from the perspective of temperature control logic. The continuous flow regulation based on the PID algorithm can allocate waste heat hot water on demand according to temperature control requirements, effectively improving the cascade utilization efficiency of low-grade waste heat in the factory area. At the same time, it keeps the supply air temperature stable, optimizes the overall thermal and humidity environment of the factory, and also reduces the operating losses of air conditioning equipment caused by frequent temperature fluctuations.

[0035] In this embodiment of the application, the feedforward calculation of the factory's cooling load at future times is performed in step S2, and the specific expression is as follows: ,in, For sensible heat load, the calculation expression is: , The heat dissipation coefficient of the corresponding device. The corresponding heat transfer coefficient of the building envelope, This represents the predicted load value for the generator set. Outdoor air temperature Set the indoor temperature. The latent heat load is calculated using the following expression: , For air supply volume, The humidity level of indoor air. The moisture content of the supplied air. It is the latent heat of vaporization of water.

[0036] In another possible embodiment, the controller first obtains the generator load forecast data for the next one to three hours from the power plant's DCS system. Then, combining the generator heat dissipation coefficient, the building envelope heat transfer coefficient, the outdoor real-time temperature, and the indoor set temperature, the sensible heat load of the plant is calculated. The sensible heat load is mainly formed by the heat dissipation of the generator operation and the heat transfer of the building envelope. Then, combining the total system air volume, indoor air humidity, air supply humidity, and the fixed latent heat of vaporization of water, the latent heat load of the plant is calculated. The latent heat load is mainly used to treat the water vapor generated by the air and personnel in the plant. Finally, the controller superimposes the sensible heat load and the latent heat load to obtain the total cooling load of the plant. Based on the load forecast results, the controller adjusts parameters such as fan air volume and chiller output in advance to achieve feedforward control. Under various operating conditions throughout the year, this calculation model can predict the heat dissipation and dehumidification needs of the plant in advance, providing accurate data support for system mode switching and equipment output adjustment.

[0037] By combining the unique heat dissipation characteristics of generator units in thermal power plant buildings and distinguishing between sensible heat load and latent heat load for quantitative calculation, the overall accuracy of cold load prediction is effectively improved. The feedforward adjustment mode based on load prediction fundamentally alleviates the lag problem of traditional feedback control, allowing HVAC equipment to adapt to load changes in advance, and the overall system operation is more stable and orderly.

[0038] In this embodiment of the application, S4 further includes variable air volume adjustment logic, that is, real-time monitoring of indoor carbon dioxide concentration, when the indoor carbon dioxide concentration exceeds the set upper limit, priority is given to increasing the fresh air volume and total air supply volume to dilute it, and after the indoor carbon dioxide concentration drops below the target value, the air supply volume is adjusted for energy saving according to the temperature deviation.

[0039] In another possible embodiment, carbon dioxide concentration sensors placed at the return air vents of the factory building first monitor indoor air quality indicators in real time. The system sets indoor air quality control as the highest priority. Then, when the indoor carbon dioxide concentration exceeds the preset upper limit, the controller will prioritize adjusting the opening of the fresh air valve and increase the operating frequency of the variable frequency fan to increase the overall air volume. The indoor carbon dioxide is diluted by outdoor fresh air until the concentration falls back to within the standard range. Then, when the carbon dioxide concentration reaches the standard, the system releases the ventilation priority constraint and switches to an energy-saving air volume adjustment mode based on indoor temperature deviation. The fan output and fresh air volume are reasonably reduced to reduce energy consumption. Finally, all air volume adjustment actions are linked with the anti-condensation control logic throughout the process. Once the adjustment of air volume and fresh air ratio triggers a condensation warning, the system will simultaneously activate the corresponding anti-condensation intervention measures. In extremely cold winter environments, when the carbon dioxide concentration in the factory building is high, the system will prioritize increasing ventilation to improve air quality, while coordinating with the adjustment of the fresh air and return air ratio to avoid low-temperature condensation problems.

[0040] By prioritizing air quality related to human respiratory health through a tiered airflow regulation logic, the system strictly ensures indoor hygiene standards in industrial plants. Once the air quality meets the standards, it automatically switches to an energy-saving operation mode to avoid energy waste caused by excessive ventilation. The airflow regulation and anti-condensation control work together to achieve a synergistic balance of multiple goals, including human comfort, electrical equipment safety, and system energy saving.

[0041] It should be noted in this embodiment that the innovative improvements of this invention are concentrated at the level of control method, control logic, and supporting control system, without modifying the existing structure of the heating, ventilation, and air conditioning (HVAC) system of a thermal power plant, such as its main body structure, equipment layout, and piping construction. Since the HVAC system of a thermal power plant is well-known prior art, this specification and its embodiments will not provide a detailed description of the inherent mechanical structure and piping arrangement of this existing system. The entire text focuses on a complete description of the innovative aspects of this invention, such as the control flow, decision rules, intervention logic, and hardware control unit, which distinguish it from existing technologies.

[0042] Example 2:

[0043] Reference Figure 2 This application also provides an adaptive energy-saving control system for a thermal power plant's heating, ventilation, and air conditioning (HVAC) system, comprising: a data acquisition unit for real-time acquisition of operating parameters of the HVAC system, including outdoor air temperature, outdoor relative humidity, indoor air temperature, indoor relative humidity, equipment surface temperature, and generator load prediction values; a load prediction unit connected to the output of the data acquisition unit for receiving the generator load prediction values ​​and performing feedforward calculations on the plant's cooling load at future times based on the generator load prediction values; and a mode switching unit connected to the outputs of the data acquisition unit and the load prediction unit, respectively, for calculating the plant's cooling load based on a comparison of outdoor and indoor air enthalpy values, and in conjunction with outdoor air... Temperature automatically switches between the first and second operating modes; the anti-condensation control unit is connected to the outputs of the data acquisition unit and the mode switching unit, respectively, and is used to calculate the condensation risk coefficient based on the difference between the equipment surface temperature and the indoor air dew point temperature in any operating mode. When the condensation risk coefficient is lower than the warning threshold, anti-condensation intervention is performed; the waste heat utilization unit is connected to the outputs of the mode switching unit and the anti-condensation control unit, respectively, and is used to utilize the low-grade waste heat of the power plant when the HVAC system is in the second operating mode. Through the waste heat reheat module set at the rear end of the air conditioning unit's surface cooler, the dehumidified air is reheated at the same humidity, raising the supply air temperature to a safe range above the dew point temperature.

[0044] In another possible embodiment, the hardware control system first adopts a hierarchical modular architecture, which includes a data acquisition unit, a load forecasting unit, a mode switching unit, an anti-condensation control unit, and a waste heat utilization unit. All units achieve bidirectional data transmission and control command linkage. The data acquisition unit integrates outdoor temperature and humidity sensors, indoor temperature and humidity sensors, carbon dioxide concentration sensors, infrared temperature sensors, and a communication module that interfaces with the power plant's DCS system. It is responsible for collecting all environmental parameters, equipment parameters, and generator load parameters required for system operation and synchronously distributing all data to the other functional units. Then, the load forecasting unit has a built-in cooling load calculation model, which receives parameters from the data acquisition unit and calculates future loads. The system calculates the cooling load feedforward and transmits the load results to the mode switching unit and the anti-condensation control unit. The mode switching unit, equipped with enthalpy and temperature determination algorithms, combines environmental parameters and load data to automatically switch operating modes and sends the current operating mode command to the anti-condensation control unit and the waste heat utilization unit. The anti-condensation control unit is responsible for dew point calculation, condensation risk determination, variable air volume adjustment, and output of various intervention commands. Finally, the waste heat utilization unit receives the mode signal and heating demand, and regulates the waste heat pipeline valves and heat exchange equipment to complete the isohyet reheat operation. The entire system can be directly embedded into the HVAC and DCS system of a newly built thermal power plant, or it can be connected to the existing control system of an existing power plant in a side-by-side manner without changing the main structure of the original equipment.

[0045] In this embodiment, the anti-condensation control unit includes: a dew point temperature calculation subunit for calculating the indoor air dew point temperature based on indoor air temperature and relative humidity; a data receiving module for receiving the equipment surface temperature collected by an infrared temperature sensor; a risk coefficient calculation subunit for calculating the condensation risk coefficient and determining a safe, warning, or dangerous state based on the numerical range; and an intervention strategy execution subunit for executing corresponding anti-condensation interventions according to the current operating mode, wherein: in the first operating mode, the opening ratio of the fresh air valve and the return air valve is adjusted and the frequency of the supply fan is reduced; in the second operating mode, the waste heat utilization unit is preferentially used to increase the supply air temperature, and when the waste heat is insufficient, the backup low-power electric reheater is activated.

[0046] In another possible embodiment, the anti-condensation control unit is first disassembled into a dew point temperature calculation subunit, a sensing subunit, a risk factor calculation subunit, and an intervention strategy execution subunit. Each subunit works collaboratively according to a fixed signal flow sequence. The dew point temperature calculation subunit receives indoor temperature and humidity parameters transmitted by the data acquisition unit, continuously calculates the indoor dew point temperature based on a predetermined fitting formula, and transmits the calculation results to the risk factor calculation subunit in real time. Then, the sensing subunit, using an infrared temperature sensor as its core hardware, continuously collects the surface temperature of key electrical equipment and synchronously uploads it to the risk factor calculation subunit. Finally, the risk factor calculation subunit combines the received data... The condensation risk coefficient is calculated from the dew point temperature and the equipment surface temperature to determine the risk level. At the same time, combined with the current system operation mode, the risk level and mode signal are sent to the intervention strategy execution subunit. Finally, the intervention strategy execution subunit has built-in differentiated intervention logic, which completes the control actions of the fresh air valve, return air valve, variable frequency fan, waste heat pipeline regulating valve, and standby electric reheater according to the received instructions. At the same time, it executes the variable air volume adjustment logic corresponding to the carbon dioxide concentration. Each subunit performs its own function and operates independently. The failure of a single subunit will not affect the normal operation of other modules. The temperature probes of the sensing subunit can also be flexibly added or removed according to the number of electrical equipment in the plant.

[0047] Furthermore, in another possible embodiment, a self-cleaning air curtain installed at the front end of the sensor continuously blows out clean airflow, preventing dust from the power plant site from adhering to the surface of the temperature measuring lens. This eliminates the need for manual cleaning and ensures long-term temperature measurement accuracy. Next, the system allows for setting a full range of adjustable parameters in the human-machine interface, including outdoor temperature switching thresholds, anti-condensation safety margins, carbon dioxide concentration alarm upper limits, and minimum opening of the fresh air valve. Maintenance personnel can flexibly modify these parameters according to the climate characteristics and on-site operational requirements of the project location, improving the system's regional adaptability. Finally, the system incorporates electric reheater priority control logic, always adhering to the switching rule of "waste heat priority, electric reheat backup," only switching when waste heat is interrupted or the flow... When the flow rate is insufficient, the electric reheater is activated to minimize electric heating energy consumption. Subsequently, all variable frequency supply and exhaust fans in the entire system adopt variable frequency soft start mode, with smooth start-up and speed adjustment processes. This avoids the current and mechanical shocks generated when fixed speed fans start and stop, extending the service life of fan motors, bearings, and blades. Finally, the system has a built-in energy consumption metering and data recording module, which can statistically analyze the power consumption of the chiller unit, fans, and electric reheater, as well as the amount of waste heat recovered and utilized in real time. The system's operating status, alarm information, and energy-saving data are displayed through a human-machine interface in the form of trend curves and operation reports. This not only allows maintenance personnel to intuitively view the energy-saving effect but also provides complete data basis for subsequent system parameter optimization and operation strategy adjustment.

[0048] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0049] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0050] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. An adaptive energy-saving control method for a heating, ventilation, and air conditioning (HVAC) system in a thermal power plant, characterized in that, Includes the following steps: S1. Real-time acquisition of operating parameters of the HVAC system, including outdoor air temperature, outdoor relative humidity, indoor air temperature, indoor relative humidity, equipment surface temperature, and generator load prediction. S2. Based on the predicted load value of the generator set, perform feedforward calculation on the cooling load of the plant at future times; S3. Based on the comparison between the outdoor air enthalpy and the indoor air enthalpy, and combined with the outdoor air temperature, automatically switch between the first operating mode and the second operating mode. S4. In any operating mode, the condensation risk coefficient is calculated based on the difference between the equipment surface temperature and the indoor air dew point temperature. When the condensation risk coefficient is lower than the warning threshold, anti-condensation intervention is performed. S5. When the HVAC system is in the second operating mode, the low-grade waste heat of the power plant is used to reheat the dehumidified air through the waste heat reheat module set at the rear end of the air conditioning unit's surface cooler, raising the supply air temperature to a safe range above the dew point temperature.

2. The adaptive energy-saving control method for the heating, ventilation, and air conditioning system of a thermal power plant according to claim 1, characterized in that, The specific criteria for determining mode switching in S3 are as follows: The outdoor air enthalpy is calculated using the air enthalpy calculation formula based on the collected outdoor air temperature and relative humidity. The indoor air enthalpy is calculated using the air enthalpy calculation formula based on the collected indoor air temperature and relative humidity. The expression for the formula for calculating the enthalpy of air is: ,in This is the enthalpy of air. The corresponding air temperature, The corresponding air humidity is determined by the corresponding air temperature and the corresponding relative humidity. When the outdoor air enthalpy is less than the indoor air enthalpy and the outdoor air temperature is less than or equal to the preset switching threshold, the outdoor cold source is determined to be usable, and the HVAC system switches to the first operating mode, that is, the refrigeration unit is turned off, the fresh air valve is opened to full opening, and the return air valve is closed; otherwise, the system switches to the second operating mode, that is, the refrigeration unit is started or maintained, the fresh air valve is adjusted to the minimum allowable opening, and the return air valve is opened.

3. The adaptive energy-saving control method for the heating, ventilation, and air conditioning system of a thermal power plant according to claim 1, characterized in that, S4 further includes: The indoor air dew point temperature is calculated based on the indoor air temperature and humidity using the following formula: ,in, , , , Indoor air temperature, in °C; The relative humidity of indoor air is expressed as a percentage (%). This refers to the indoor air dew point temperature. The surface temperature of the device is obtained using an infrared temperature sensor; The condensation risk coefficient is calculated based on the surface temperature of the equipment and the dew point temperature of the indoor air. Based on the numerical range of the condensation risk coefficient, the state is determined to be safe, warning, or dangerous, and corresponding anti-condensation intervention strategies are triggered.

4. The adaptive energy-saving control method for the heating, ventilation, and air conditioning system of a thermal power plant according to claim 3, characterized in that, The anti-condensation intervention strategy specifically includes: In the first operating mode, the opening ratio of the fresh air valve and the return air valve is adjusted to introduce some hot return air to increase the supply air temperature, while the frequency of the supply fan is reduced to reduce the supply air speed. In the second operating mode, the waste heat reheat module is used first to increase the supply air temperature. When the waste heat is insufficient, the backup low-power electric reheater is activated.

5. The adaptive energy-saving control method for the heating, ventilation, and air conditioning system of a thermal power plant according to claim 1, characterized in that, In step S5, the target supply air temperature is set as the sum of the indoor air dew point temperature and a preset safety margin. The flow rate of hot water entering the waste heat exchange coil is controlled via PID regulation to ensure that the actual supply air temperature is controlled within a preset deviation range of the target supply air temperature. The expression for the target supply air temperature is: ,in, For the target supply air temperature, This refers to the indoor air dew point temperature. This is a preset safety margin.

6. The adaptive energy-saving control method for the heating, ventilation, and air conditioning system of a thermal power plant according to claim 1, characterized in that, In step S2, the feedforward calculation of the factory's cooling load at future times is specifically expressed as follows: ,in, For sensible heat load, the calculation expression is: , The heat dissipation coefficient of the corresponding device. The corresponding heat transfer coefficient of the building envelope, This represents the predicted load value for the generator set. Outdoor air temperature Set the indoor temperature. The latent heat load is calculated using the following expression: , For air supply volume, The humidity level of indoor air. The moisture content of the supplied air. It is the latent heat of vaporization of water.

7. The adaptive energy-saving control method for the heating, ventilation, and air conditioning system of a thermal power plant according to claim 1, characterized in that, The S4 also includes variable air volume regulation logic, which monitors the indoor carbon dioxide concentration in real time. When the indoor carbon dioxide concentration exceeds the set upper limit, the fresh air volume and total air supply volume are increased first to dilute it. After the indoor carbon dioxide concentration drops below the target value, the air supply volume is adjusted for energy saving based on the temperature deviation.

8. An adaptive energy-saving control system for a heating, ventilation, and air conditioning system in a thermal power plant, characterized in that, An adaptive energy-saving control method for a thermal power plant HVAC system as described in any one of claims 1-7, comprising: The data acquisition unit is used to collect the operating parameters of the HVAC system in real time. The operating parameters include outdoor air temperature, outdoor air relative humidity, indoor air temperature, indoor air relative humidity, equipment surface temperature, and generator load prediction. The load forecasting unit is connected to the output of the data acquisition unit and is used to receive the load forecast value of the generator set and perform feedforward calculation of the plant's cooling load at future times based on the load forecast value of the generator set. The mode switching unit is connected to the output terminals of the data acquisition unit and the load prediction unit respectively, and is used to automatically switch between the first operating mode and the second operating mode based on the comparison results of the outdoor air enthalpy value and the indoor air enthalpy value, and in combination with the outdoor air temperature. The anti-condensation control unit is connected to the output terminals of the data acquisition unit and the mode switching unit, respectively. It is used to calculate the condensation risk coefficient based on the difference between the equipment surface temperature and the indoor air dew point temperature in any operating mode. When the condensation risk coefficient is lower than the warning threshold, anti-condensation intervention is performed. The waste heat utilization unit is connected to the output terminals of the mode switching unit and the anti-condensation control unit, respectively. When the HVAC system is in the second operating mode, it utilizes the low-grade waste heat from the power plant to perform isohumid reheating on the dehumidified air through the waste heat reheat module located at the rear end of the air conditioning unit's surface cooler, thereby raising the supply air temperature to a safe range above the dew point temperature.

9. The adaptive energy-saving control system for the HVAC system of a thermal power plant according to claim 8, characterized in that, The anti-condensation control unit includes: The dew point temperature calculation subunit is used to calculate the indoor air dew point temperature based on the indoor air temperature and relative humidity. The data receiving module is used to receive the surface temperature of the device collected by the infrared temperature sensor; The risk coefficient calculation subunit is used to calculate the condensation risk coefficient and determine the safe, warning, or dangerous state based on the numerical range. The intervention strategy execution subunit is used to perform corresponding anti-condensation interventions according to the current operating mode. In the first operating mode, the opening ratio of the fresh air valve and the return air valve is adjusted and the frequency of the supply air fan is reduced. In the second operating mode, the waste heat utilization unit is used first to increase the supply air temperature. When the waste heat is insufficient, the backup low-power electric reheater is activated.

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