Clean room purge air conditioning control system

Abstract

The application discloses a clean room purification air conditioner control system and belongs to the technical field of clean room purification air conditioner control. The system comprises a temperature and humidity control module, a filter control module and an air volume control module. The three modules are coupled with each other, the control precision is improved, the operation energy consumption is reduced and the maintenance cost is lowered under the premise of guaranteeing the cleanliness, temperature and humidity and pressure difference safety of the clean room.

Description

Technical Field

[0001] This invention relates to the field of cleanroom air conditioning control technology, and more specifically to a cleanroom air conditioning control system. Background Technology

[0002] Currently, cleanroom air conditioning systems generally adopt conventional control strategies such as independent temperature and humidity control, regular filter replacement, and a fixed fresh air-to-return air ratio to ensure the cleanliness, temperature, humidity, and pressure difference requirements within the cleanroom.

[0003] However, the aforementioned existing technologies have the following shortcomings in actual operation: First, under traditional temperature and humidity control methods, there is a significant time lag between the action of the actuator and changes in the air supply parameters, making it difficult to respond promptly to outdoor climate fluctuations and indoor load changes, resulting in large temperature and humidity fluctuations and low control accuracy. Simultaneously, temperature and humidity regulation are coupled, and temperature fluctuations can cause changes in relative humidity, interfering with humidity-sensitive process environments. Second, filter maintenance often relies on periodic replacement, differential pressure threshold alarms, or manual inspections, which cannot predict filter clogging trends and remaining lifespan in real time, easily leading to insufficient maintenance or excessive replacement, and even the risk of cleanroom contamination due to filter damage. Third, the fresh air-to-return air ratio is usually fixed or only roughly adjusted according to the season, failing to dynamically optimize based on outdoor meteorological parameters. During transitional seasons, free fresh air cooling sources cannot be fully utilized, and during cooling or heating seasons, introducing excessive fresh air increases unnecessary load, leading to high system energy consumption.

[0004] Therefore, how to provide a cleanroom air conditioning control system that can achieve precise decoupled control of temperature and humidity, intelligent early warning and maintenance of filters, and dynamic optimization of the fresh and return air ratio is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a cleanroom air conditioning control system to improve control accuracy, reduce operating energy consumption, and reduce maintenance costs while ensuring the safety of the cleanroom process environment.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A cleanroom air conditioning control system includes: The temperature and humidity control module is used to perform feedforward control of the surface cooler, heater and humidifier based on outdoor weather forecast data, and to perform cascade feedback control of the surface cooler, heater and humidifier based on the actual value and target value of indoor temperature and humidity. The temperature and humidity control module adopts a decoupled control strategy that prioritizes humidity content. The filter control module, connected to the temperature and humidity control module, is used to collect the real-time differential pressure of the filter, perform trend analysis on historical differential pressure data to predict the remaining service life, and trigger graded early warnings based on the remaining service life or the current differential pressure value. The air volume control module is connected to the temperature and humidity control module and the filter control module respectively. It is used to determine the energy-saving mode based on the comparison between the outdoor air enthalpy value and the indoor air enthalpy value, and dynamically optimize the fresh air return ratio based on the energy-saving mode and the minimum fresh air volume required to maintain the positive pressure of the clean room. When adjusting the air valve, it maintains a constant indoor pressure difference through feedforward compensation.

[0007] Furthermore, the temperature and humidity control module includes: The main circuit control unit is used to generate supply air temperature and humidity setpoints based on the target and actual indoor temperature and humidity values. The secondary loop control unit is used to generate feedback control quantities based on the supply air temperature and humidity setpoint and the actual supply air temperature and humidity values. The outdoor weather forecast data is used to generate a feedforward control quantity, which is used to adjust the output of the secondary loop control unit in advance or to directly act on the actuator.

[0008] Furthermore, the moisture content-priority decoupling control strategy includes: The actual indoor humidity is calculated based on indoor temperature and relative humidity. When the deviation between the actual indoor humidity and the preset humidity target value exceeds a threshold, the humidifier is adjusted first to eliminate the humidity deviation, and the temperature control command is limited during this stage.

[0009] Furthermore, the filter control module includes: The data acquisition and preprocessing unit is used to acquire the differential pressure values ​​of each filter; The reference differential pressure establishment unit is used to record the initial differential pressure value after the filter is initially installed; The differential pressure change trend analysis unit is used to analyze the rate of differential pressure change using linear regression or exponential regression algorithms. The lifespan prediction unit is used to calculate the remaining lifespan based on the current differential pressure value, a preset replacement threshold, and the rate of change of the differential pressure. The graded early warning unit is used to trigger different levels of early warning signals based on the ratio between the remaining service life or the current differential pressure value and the replacement threshold.

[0010] Furthermore, the tiered early warning unit includes: A Level 1 warning is triggered when the differential pressure reaches the first percentage of the replacement threshold or when the remaining service life is less than or equal to the first day; a Level 2 warning is triggered when the differential pressure reaches the second percentage of the replacement threshold or when the remaining service life is less than or equal to the second day; and a Level 3 warning is triggered when the differential pressure reaches the third percentage of the replacement threshold or when the remaining service life is less than or equal to the third day. The proportions are: first ratio < second ratio < third ratio, and the number of days on the first day > the number of days on the second day > the number of days on the third day.

[0011] Furthermore, in the airflow control module, determining the energy-saving mode includes: When the outdoor air enthalpy is greater than the sum of the indoor air enthalpy and the hysteresis interval, it is determined to be the cooling season mode; when the absolute value of the difference between the outdoor air enthalpy and the indoor air enthalpy is less than or equal to the hysteresis interval, it is determined to be the transition season mode; when the outdoor air enthalpy is less than the difference between the indoor air enthalpy and the hysteresis interval, it is determined to be the heating season mode.

[0012] Furthermore, the dynamic optimization of the new return air ratio includes: In cooling or heating season mode, the fresh air-return ratio is optimized to the proportion that only meets the minimum fresh air volume required to maintain positive pressure in the cleanroom; in transition season mode, the fresh air-return ratio is optimized to the maximum value under the constraints of meeting the minimum fresh air volume and the maximum allowable fresh air-return ratio of the system.

[0013] Furthermore, the airflow control module also includes: The execution unit is used to gradually change the opening of the air valve in a ramp adjustment manner, and monitor the indoor temperature, humidity and pressure difference during the adjustment process. When an over-limit trend occurs, it will pause or reverse.

[0014] Furthermore, the airflow control module also includes: The coordination unit is used to send the optimized new air supply status parameters to the temperature and humidity control module for feedforward coordinated adjustment.

[0015] Furthermore, the filter control module also includes: The abnormality diagnosis unit is used to monitor abnormal fluctuations in the rate of differential pressure change and to issue a warning of filter damage or abnormal airflow when the rate of differential pressure change suddenly increases.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention provides a cleanroom air conditioning control system that achieves precise control, energy-saving operation, intelligent maintenance, and visualized management of the cleanroom air conditioning system. While ensuring the safety of the cleanroom process, it achieves the ultimate energy-saving effect of on-demand supply. It has the following beneficial effects: (1) The introduction of meteorological data feedforward predictive control allows for advance adjustment before outdoor load changes are transmitted to the indoor environment, overcoming the thermal inertia delay of traditional control. Simultaneously, combined with a cascade control architecture, the main loop sets the air supply target, and the secondary loop responds quickly to disturbances, significantly improving control response speed and stability. A moisture content-priority decoupling strategy is adopted, using absolute humidity as the control variable to avoid interference from temperature fluctuations on humidity control, ensuring high-precision control of humidity-sensitive process environments and effectively preventing microbial growth or electrostatic hazards. (2) By predicting load changes through meteorological feedforward, the waste of cooling capacity caused by excessive adjustment is avoided; by dynamically optimizing the fresh air-return air ratio through enthalpy comparison, the outdoor fresh air is fully utilized for free cooling during the transition season, and the fresh air volume is automatically reduced during the cooling / heating season to reduce the load of the surface cooler / heater; at the same time, the intelligent early warning of the filter avoids the overload operation of the fan due to blockage. (3) Continuous monitoring and trend analysis of filter differential pressure are performed, and linear or exponential regression is used to predict the remaining service life. A tiered early warning system is also implemented, enabling maintenance personnel to be aware of replacement needs in advance, arrange spare parts procurement and maintenance plans, and avoid emergency procurement and passive downtime. Simultaneously, the anomaly diagnosis unit can identify sudden changes in differential pressure, providing timely warnings of filter damage or abnormal airflow, thus eliminating the risk of cleanroom contamination. As a result, filter replacement costs are reduced, the number of emergency procurements is decreased, and system reliability is improved. (4) The air volume control system uses a ramp adjustment method to change the opening of the air valve, avoiding temperature, humidity and pressure fluctuations caused by step changes; the pressure difference feedforward compensation unit adjusts the exhaust valve simultaneously when adjusting the fresh air return ratio to maintain a constant indoor pressure difference. The temperature and humidity control subsystem and the air volume control subsystem are linked through a collaborative unit to achieve feedforward information interaction, further suppressing disturbances. The overall control is smooth and has little impact, extending the service life of actuators and fans. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the system structure provided by the present invention; Figure 2 A schematic diagram of the temperature and humidity control module provided by the present invention; Figure 3 A schematic diagram of the air volume control module provided by the present invention. Detailed Implementation

[0019] 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.

[0020] See Figure 1This invention discloses a cleanroom air conditioning control system, comprising three main parts: a temperature and humidity control module, a filter control module, and an airflow control module. These three modules are coupled together to jointly ensure the cleanliness, temperature, humidity, and differential pressure safety of the cleanroom.

[0021] See Figure 2 In one specific embodiment, the temperature and humidity control module incorporates meteorological data prediction control and cascade control. Under traditional control methods, there is a significant time lag between the receiving of the chilled water valve's opening signal and the change in chilled water flow, coil temperature, and ultimately, the supply air temperature. This lag makes it difficult for the system to respond promptly to load changes, easily leading to problems such as large temperature and humidity fluctuations and inaccurate control.

[0022] To overcome the aforementioned shortcomings, this invention introduces a predictive control mechanism based on meteorological data. By accessing outdoor temperature and humidity forecast data for future time periods, the system can predict the building's upcoming heat load before outdoor climate changes are transmitted to the indoor environment. Based on this, it adjusts the opening of the chilled water valve in advance, ensuring that the coil temperature change trend is synchronized with the upcoming load demand, thereby effectively offsetting the control delay caused by thermal inertia.

[0023] Considering the inherent errors in weather forecast data and the inability to achieve complete accuracy, this invention retains a real-time feedback control loop in addition to predictive control. The system continuously collects actual indoor temperature and humidity data, dynamically correcting the predictive control results to ensure accurate and stable environmental control under various operating conditions. Precise load prediction avoids wasted cooling capacity due to over-adjustment, while the stable operation of the chiller unit helps maintain its high-efficiency operating range, thereby reducing overall system energy consumption.

[0024] Introducing cascade control, including: The main circuit control unit is used to generate supply air temperature and humidity setpoints based on the preset indoor temperature and humidity target values ​​and the actual indoor temperature and humidity values ​​detected by the indoor temperature and humidity sensor. The secondary loop control unit is used to generate control commands based on the supply air temperature and humidity setpoint and the actual supply air temperature and humidity values ​​detected by the supply air temperature and humidity sensor. An actuator drive unit is used to adjust the opening degree of the cold water valve of the surface cooler, the opening degree of the hot water valve of the heater, and the opening degree of the valve of the humidifier according to the control command.

[0025] Specifically, this invention employs a decoupled control strategy prioritizing humidity, automatically switching to a humidity-priority control mode when the humidity deviation exceeds a preset threshold, ensuring the priority of humidity control. This is particularly important for humidity-sensitive cleanroom processes (such as biopharmaceuticals and precision electronics manufacturing), effectively preventing microbial growth due to excessive humidity or electrostatic hazards due to excessively low humidity, significantly improving process safety. Preferably, the humidity main loop control unit uses absolute humidity (humidity d) instead of relative humidity as the control variable. Since absolute humidity is unaffected by temperature changes, it more accurately reflects the water vapor content in the air. Using absolute humidity as the control target effectively avoids humidity control interference caused by temperature fluctuations.

[0026] Connected to the indoor temperature and humidity sensor, it is used to calculate the actual indoor humidity d_in based on the detected indoor temperature T_in and indoor relative humidity RH_in, according to the following formula:

[0027] Where P_sat(T_in) is the saturated water vapor pressure at temperature T_in, and P_atm is the local atmospheric pressure; 1) Moisture content main circuit control: The moisture content main loop control unit is used to calculate and generate the supply air moisture content setpoint d_sup_set based on the preset indoor moisture content target value d_set and the actual indoor moisture content d_in calculated by the moisture content calculation unit. The moisture content main loop control unit adopts a proportional-integral-derivative control algorithm, and its control period is set to T_d1. The moisture content main loop control unit acts as the main controller, and its output priority is higher than that of the temperature control loop. When the moisture content deviation exceeds the preset threshold, the moisture content control command will take priority in occupying the actuator resources.

[0028] 2) Temperature main loop control: The temperature main loop control unit is used to calculate and generate the supply air temperature setpoint T_sup_set based on the preset indoor temperature target value T_set and the actual indoor temperature value T_in detected by the indoor temperature and humidity sensor. The temperature main loop control unit adopts a proportional-integral-derivative control algorithm. As a compensation controller, the output of the temperature main loop control unit is limited by the humidity control state. When the humidity control is in the priority adjustment stage, the temperature control command is limited and only compensates for the temperature deviation caused by the humidity adjustment.

[0029] In one specific embodiment, during operation, as the amount of contaminants intercepted gradually increases, the filter screen becomes increasingly clogged, resulting in a gradual increase in the pressure difference across the filter. When the pressure difference reaches a certain value, the filter needs to be replaced; otherwise, the following problems will occur: First, insufficient airflow and decreased cleanliness. After the filter becomes clogged, the airflow resistance increases, and with the fan speed remaining constant, the airflow will decrease significantly, leading to insufficient air changes in the cleanroom and compromising cleanliness. Second, a significant increase in energy consumption. To overcome the increased resistance, the fan needs to increase its speed, thus increasing energy consumption. When the filter is severely clogged, the fan may operate under overload for extended periods, not only consuming more electricity but also potentially shortening its lifespan. Third, excessive pressure difference may cause filter damage. When the pressure difference across the filter exceeds its structural limits, the filter paper may rupture, releasing the intercepted particles instantly and causing a serious cleanroom contamination incident.

[0030] In existing technologies, filter replacement is typically performed in the following ways: Regular replacement: Replace the filter at fixed intervals (such as every six months or every year). This method has obvious drawbacks—replacing it too early is wasteful, while replacing it too late may affect the cleanliness.

[0031] Threshold alarm system: Differential pressure sensors are installed before and after the filter. When the differential pressure reaches a set threshold (such as twice the initial differential pressure), an alarm signal is issued. Although this method is more reasonable than periodic replacement, it still has shortcomings—the alarm only sounds when the differential pressure reaches the threshold, and maintenance personnel need time to respond. During this period, the system may already be in a suboptimal operating state; moreover, it is impossible to predict the remaining lifespan of the filter, which is not conducive to spare parts procurement and maintenance planning.

[0032] Manual inspection system: Maintenance personnel periodically read the differential pressure gauge readings and manually determine whether replacement is needed. This method relies on personnel experience and cannot achieve real-time monitoring and early warning.

[0033] The filter control module of this invention adopts eight units for coordinated control: data acquisition and preprocessing unit, reference differential pressure establishment unit, differential pressure change trend analysis unit, remaining life prediction unit, graded early warning unit, and anomaly diagnosis unit.

[0034] Specifically, the data acquisition and preprocessing unit is used for: Collect the differential pressure value ΔP_i of each filter (i=1,2 correspond to the primary and secondary filters respectively); The collected data is filtered to eliminate transient fluctuations and interference. Specifically, the reference differential pressure establishment unit is used to record the initial differential pressure value ΔP_0i of the system under standard operating conditions after the initial installation of the filter: After the new filter is installed and the system is running stably, the current differential pressure value is automatically recorded as the initial reference. Accepts manually input nominal value of initial differential pressure; The reference pressure difference is used for subsequent assessment of the degree of blockage.

[0035] Specifically, the differential pressure change trend analysis unit is used for: Historical differential pressure data are stored, and differential pressure-time series {(t_j, ΔP_ij)} for each filter are constructed. Linear regression or exponential regression algorithms are used to analyze the trend of pressure difference over time and calculate the rate of pressure difference change k_i=d(ΔP_i) / dt. Based on historical data, predict the pressure difference value at future moments: ΔP_i(t)=ΔP_i(t0)+k_i×(t-t0) (linear model) or ΔP_i(t)=ΔP_i(t0)×exp(β_i×(t-t0)) (exponential model); Assess the clogging rate of different filters and identify abnormally accelerated clogging situations.

[0036] Specifically, the remaining lifetime prediction unit is used for: Based on the replacement threshold ΔP_max_i of each filter (usually 2-2.5 times the initial differential pressure, or determined according to the filter specification), combined with the current differential pressure value ΔP_i and the rate of change k_i, the remaining service life of the filter is calculated: RL_i=(1 / β_i)×ln(ΔP_max_i / ΔP_i) (exponential model) For multi-stage filters, comprehensive maintenance recommendations are provided, taking into account the remaining lifespan of each stage of the filter.

[0037] Specifically, the graded early warning unit is used to trigger early warning signals of different levels based on the remaining lifetime RL_i and the current pressure difference ΔP_i: Level 1 Warning (Attention Level): When ΔP_i≥0.7×ΔP_max_i or RL_i≤30 days, a yellow warning is issued, prompting maintenance personnel to pay attention to the filter and prepare spare parts; Level 2 warning (warning level): When ΔP_i≥0.85×ΔP_max_i or RL_i≤14 days, an orange warning is issued, prompting a replacement to be arranged in the near future; Level 3 warning (alarm level): When ΔP_i≥0.95×ΔP_max_i or RL_i≤3 days, a red alarm is issued, prompting immediate replacement arrangements; Over-limit alarm: When ΔP_i≥ΔP_max_i, an emergency alarm is issued, indicating that the filter has exceeded the limit and needs to be stopped and replaced immediately.

[0038] Specifically, the abnormal diagnosis unit is used to: monitor the abnormal fluctuations of the pressure difference change rate, and when k_i suddenly increases significantly, it indicates that there may be abnormal situations such as filter breakage or sudden increase in air volume; compare the pressure difference change laws of filters of the same model in different units to identify the abnormal clogging of individual filters. In a specific embodiment, refer to Figure 3 , the air volume control module is configured to execute the following new return air ratio dynamic optimization control logic, using seven major calculation units: data acquisition and calculation unit, fresh air demand calculation unit, enthalpy comparison and mode judgment unit, economic new return air ratio optimization unit, pressure difference feedforward compensation unit, variable new return air ratio execution unit, and coordination unit with the temperature and humidity control system. The seven major units work together to form a closed-loop control, continuously and dynamically optimize the new return air ratio, and achieve maximum energy conservation on the premise of ensuring the safe operation of the clean room.

[0039] Specifically, the data acquisition and calculation unit is used to: Real-time collect the outdoor temperature and humidity (T_out, RH_out), and calculate the outdoor air enthalpy h_out; Real-time collect the indoor temperature and humidity (T_in, RH_in), and calculate the indoor air enthalpy h_in; Real-time collect the indoor pressure difference ΔP; Real-time collect the fresh air volume Q_fresh, return air volume Q_return, and supply air volume Q_supply; Calculate the current new return air ratio R = Q_fresh / Q_return.

[0040] Specifically, the fresh air demand calculation unit is used to calculate the minimum fresh air volume Q_min that meets the following conditions according to the clean room specification requirements: the fresh air volume required to maintain the positive pressure of the clean room (calculated according to the pressure difference requirement and the room air leakage); Specifically, the enthalpy comparison and mode judgment unit is used to compare the outdoor enthalpy h_out with the indoor enthalpy h_in to judge the energy-saving mode to which the current working condition belongs: Cooling season mode: When h_out > h_in + δ_h (δ_h is the hysteresis interval to prevent frequent switching), the outdoor air enthalpy is higher than the indoor, and introducing outdoor fresh air will increase the cooling load. At this time, the fresh air volume should be reduced as much as possible; Transition season mode: When |h_out - h_in| ≤ δ_h, the outdoor air enthalpy is close to the indoor, and the fresh air can be fully utilized. At this time, on the basis of meeting the minimum fresh air volume, the fresh air ratio can be increased as much as possible; Heating season mode: When h_out < h_in - δ_h, the outdoor air enthalpy is lower than the indoor, and introducing outdoor fresh air will increase the heating load. At this time, the fresh air volume should be reduced as much as possible.

[0041] Specifically, the economic new return air ratio optimization unit is used to calculate the optimal new return air ratio under different modes: Cooling season mode (h_out>h_in+δ_h); At this time, fresh air should be minimized to reduce the cooling load. The optimal fresh-to-return air ratio R_opt should be minimized. R_opt=Q_min / Q_supply; This means that the fresh air volume is maintained at the minimum value that meets hygiene and pressure difference requirements.

[0042] Transitional season pattern (|h_out-h_in|≤δ_h); At this point, the outdoor air enthalpy is close to the indoor enthalpy, so introducing fresh air will not increase the load; on the contrary, it may reduce the burden on the surface cooler / heater. The optimal fresh-return air ratio can be maximized under the following constraints: Fresh air volume ≤ Supply air volume - Minimum return air volume (to ensure normal operation of return air duct); Fresh air volume ≥ Q_min; During the adjustment process, the pressure difference fluctuation shall not exceed the allowable range (e.g., ±2Pa).

[0043] R_opt=min(R_max, (Q_supply-Q_return_min) / Q_supply)

[0044] Where R_max is the maximum allowable fresh air to return air ratio of the system (usually determined by the design of the mixing section, such as 70%), and Q_return_min is the minimum return air volume to maintain the normal operation of the return air duct.

[0045] Heating season mode (h_out) <h_in-δ_h); At this time, fresh air should be minimized to reduce heat load. The optimal fresh-to-return air ratio should also be minimized. R_opt=Q_min / Q_supply; Specifically, the differential pressure feedforward compensation unit is used to pre-calculate the impact of damper operation on indoor differential pressure during the adjustment of the fresh air-return ratio, and to perform dynamic compensation. When the fresh air valve is fully open and the return air valve is fully closed, the indoor positive pressure tends to increase while the supply air volume remains constant. The differential pressure feedforward compensation unit calculates the opening of the exhaust valve that needs to be adjusted synchronously based on the preset valve-differential pressure characteristic model, so that the exhaust air volume increases synchronously and the differential pressure remains constant.

[0046] Compensation algorithm: ΔQ_exhaust = ΔQ_fresh - ΔQ_return; Wherein, ΔQ_fresh is the change in fresh air volume, ΔQ_return is the change in return air volume, and ΔQ_exhaust is the change in exhaust air volume that needs to be adjusted.

[0047] Specifically, the variable return air ratio execution unit is used for: Based on the target fresh air-return air ratio R_target calculated by the economic fresh air-return air ratio optimization unit, calculate the target opening degree of the corresponding fresh air valve, return air valve and exhaust air valve; The slope adjustment method is adopted to gradually change the opening of the air valve at a preset rate, so as to avoid fluctuations in temperature, humidity and pressure difference caused by abrupt changes. During the adjustment process, the indoor temperature, humidity and pressure difference are monitored in real time. If the trend of exceeding the limit is observed, the adjustment is immediately suspended or reversed. After adjustment, record the current new return air ratio and enter the steady-state monitoring stage.

[0048] Specifically, the coordination unit with the temperature and humidity control system is used to link the fresh air-to-return air ratio optimization with the temperature and humidity control system: When the fresh return air ratio changes, the air supply state changes accordingly, and the coordination unit sends the new air supply state parameters to the secondary loop of the cascade control system in real time. The secondary circuit quickly adjusts the opening of the chilled water valve / hot water valve according to the new air supply status to ensure that the air supply temperature and humidity meet the standards. This feedforward coordination avoids fluctuations in indoor temperature and humidity caused by changes in the fresh air-to-return air ratio.

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cleanroom air conditioning control system, characterized in that, include: The temperature and humidity control module is used to perform feedforward control of the surface cooler, heater and humidifier based on outdoor weather forecast data, and to perform cascade feedback control of the surface cooler, heater and humidifier based on the actual value and target value of indoor temperature and humidity. The temperature and humidity control module adopts a decoupled control strategy that prioritizes humidity content. The filter control module, connected to the temperature and humidity control module, is used to collect the real-time differential pressure of the filter, perform trend analysis on historical differential pressure data to predict the remaining service life, and trigger graded early warnings based on the remaining service life or the current differential pressure value. The air volume control module is connected to the temperature and humidity control module and the filter control module respectively. It is used to determine the energy-saving mode based on the comparison between the outdoor air enthalpy value and the indoor air enthalpy value, and dynamically optimize the fresh air return ratio based on the energy-saving mode and the minimum fresh air volume required to maintain the positive pressure of the clean room. When adjusting the air valve, it maintains a constant indoor pressure difference through feedforward compensation.

2. The cleanroom air conditioning control system according to claim 1, characterized in that, The temperature and humidity control module includes: The main circuit control unit is used to generate supply air temperature and humidity setpoints based on the target and actual indoor temperature and humidity values. The secondary loop control unit is used to generate feedback control quantities based on the supply air temperature and humidity setpoint and the actual supply air temperature and humidity values. The outdoor weather forecast data is used to generate a feedforward control quantity, which is used to adjust the output of the secondary loop control unit in advance or to directly act on the actuator.

3. The cleanroom air conditioning control system according to claim 1, characterized in that, The moisture content-priority decoupling control strategy includes: The actual indoor humidity is calculated based on indoor temperature and relative humidity. When the deviation between the actual indoor humidity and the preset humidity target value exceeds a threshold, the humidifier is adjusted first to eliminate the humidity deviation, and the temperature control command is limited during this stage.

4. The cleanroom air conditioning control system according to claim 1, characterized in that, The filter control module includes: The data acquisition and preprocessing unit is used to acquire the differential pressure values ​​of each filter; The reference differential pressure establishment unit is used to record the initial differential pressure value after the filter is initially installed; The differential pressure change trend analysis unit is used to analyze the rate of differential pressure change using linear regression or exponential regression algorithms. The lifespan prediction unit is used to calculate the remaining lifespan based on the current differential pressure value, a preset replacement threshold, and the rate of change of the differential pressure. The graded early warning unit is used to trigger different levels of early warning signals based on the ratio between the remaining service life or the current differential pressure value and the replacement threshold.

5. A cleanroom air conditioning control system according to claim 4, characterized in that, The hierarchical early warning unit includes: A Level 1 warning is triggered when the differential pressure reaches the first percentage of the replacement threshold or when the remaining service life is less than or equal to the first day; a Level 2 warning is triggered when the differential pressure reaches the second percentage of the replacement threshold or when the remaining service life is less than or equal to the second day; and a Level 3 warning is triggered when the differential pressure reaches the third percentage of the replacement threshold or when the remaining service life is less than or equal to the third day. The proportions are: first ratio < second ratio < third ratio, and the number of days on the first day > the number of days on the second day > the number of days on the third day.

6. A cleanroom air conditioning control system according to claim 1, characterized in that, In the airflow control module, determining the energy-saving mode includes: When the outdoor air enthalpy is greater than the sum of the indoor air enthalpy and the hysteresis interval, it is determined to be the cooling season mode; when the absolute value of the difference between the outdoor air enthalpy and the indoor air enthalpy is less than or equal to the hysteresis interval, it is determined to be the transition season mode; when the outdoor air enthalpy is less than the difference between the indoor air enthalpy and the hysteresis interval, it is determined to be the heating season mode.

7. A cleanroom air conditioning control system according to claim 6, characterized in that, The dynamically optimized fresh return air ratio includes: In cooling or heating season mode, the fresh air-return ratio is optimized to the proportion that only meets the minimum fresh air volume required to maintain positive pressure in the cleanroom; in transition season mode, the fresh air-return ratio is optimized to the maximum value under the constraints of meeting the minimum fresh air volume and the maximum allowable fresh air-return ratio of the system.

8. A cleanroom air conditioning control system according to claim 1, characterized in that, The air volume control module also includes: The execution unit is used to gradually change the opening of the air valve in a ramp adjustment manner, and monitor the indoor temperature, humidity and pressure difference during the adjustment process. When an over-limit trend occurs, it will pause or reverse.

9. A cleanroom air conditioning control system according to claim 1, characterized in that, The air volume control module also includes: The coordination unit is used to send the optimized new air supply status parameters to the temperature and humidity control module for feedforward coordinated adjustment.

10. A cleanroom air conditioning control system according to claim 1, characterized in that, The filter control module also includes: The abnormality diagnosis unit is used to monitor abnormal fluctuations in the rate of differential pressure change and to issue a warning of filter damage or abnormal airflow when the rate of differential pressure change suddenly increases.

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