A clean room independent decoupling clean air conditioning system and a control method thereof

Abstract

The application discloses a clean workshop independent decoupling clean air conditioning system and a control method thereof, and belongs to the field of clean air conditioning system. The clean workshop independent decoupling clean air conditioning system comprises a cleanliness control module, a temperature control module and a humidity and positive pressure control module. The cleanliness control module is used for bearing clean air supply and particle control in a clean room. The temperature control module comprises a coil pipe and is used for bearing sensible heat load processing in the clean room. The temperature control module runs in a dry working condition by taking medium-temperature water as refrigerant and inputting the refrigerant into the coil pipe. The surface temperature of the coil pipe is always higher than the dew point temperature of indoor air. The humidity and positive pressure control module is used for bearing fresh air load, latent heat load and positive pressure maintenance in the clean room. The cleanliness control module, the temperature control module and the humidity and positive pressure control module are independently realized by air volume decoupling, load decoupling and control decoupling modes, and cooperatively maintain the cleanliness, temperature, humidity and positive pressure of the clean room environment in a steady state. The application adopts the independent decoupling design, controls the cleanliness and temperature and humidity, has no condensation risk in the dry working condition, is energy-saving and convenient to operate and maintain.

Description

Technical Field

[0001] This application relates to an independent decoupled cleanroom air conditioning system and its control method, belonging to the field of air conditioning system technology. Background Technology

[0002] Cleanrooms have strict requirements for coordinated control of temperature, humidity, cleanliness, and positive pressure. Early cleanroom air conditioning systems used independent control of temperature, humidity, and FFU start / stop. However, there were significant mutual constraints among the control loops: adjusting the temperature would affect the dehumidification effect, adjusting the humidity would interfere with the positive pressure and air supply uniformity, and maintaining the large circulation air volume would in turn affect the stability of temperature and humidity. This resulted in system oscillation, low control accuracy, and lag in response, making it impossible to achieve independent and precise control.

[0003] Therefore, traditional cleanroom air conditioning systems mostly adopt a centralized return air processing mode. Although this avoids direct conflicts between independent loops, it brings defects such as high energy consumption due to temperature and humidity coupling, easy growth of microorganisms in condensate and the risk of pollution, and difficulty in independently matching the cleanroom circulating air volume with the fresh air volume and load air volume as needed. Existing FFU plus dry coil solutions are also mostly simple equipment stacking, lacking systematic decoupling design, and still have not solved the problem of inter-loop constraints. Therefore, there is an urgent need for a cleanroom air conditioning system that can eliminate mutual interference between control loops and achieve truly independent and precise control. Summary of the Invention

[0004] According to one aspect of this application, a cleanroom independent decoupled air conditioning system is provided. The system adopts a three-module independent decoupled design to control cleanliness and temperature and humidity. There is no risk of condensation in dry conditions, and it is energy-saving and easy to operate and maintain.

[0005] A cleanroom independent decoupled air conditioning system includes: The cleanliness control module is located in the upper part of the cleanroom ceiling. It is responsible for clean air supply and particulate control in the cleanroom, but does not participate in temperature and humidity control. The temperature control module is located in the technical interlayer inside the ceiling of the clean room. The temperature control module includes a coil for handling the sensible heat load in the clean room. Medium-temperature water is used as the refrigerant and is introduced into the coil. The difference between the supply temperature of the medium-temperature water and the dew point temperature of the indoor air is set to be no less than 2~5℃, so that the temperature control module operates under dry conditions and the surface temperature of the coil is always higher than the dew point temperature of the indoor air. The humidity and positive pressure control module, including the fresh air handling unit and air supply duct, is used to handle the fresh air load, latent heat load and positive pressure maintenance in the clean room; The cleanliness control module, temperature control module, and humidity and positive pressure control module achieve functional independence through air volume decoupling, load decoupling, and control decoupling. During steady-state operation, they work together to maintain the cleanliness, temperature, humidity, and positive pressure of the cleanroom environment. The circulating air volume of the cleanliness control module is calculated according to the cleanliness requirements, and the fresh air volume of the humidity and positive pressure control module is calculated based on the largest value among the sum of the positive pressure maintenance and compensation exhaust air volume, the dehumidification air volume, and the minimum fresh air volume for personnel. The fresh air volume and the circulating air volume are independent of each other.

[0006] Furthermore, the cleanliness control module includes multiple FFU units, which are arranged in the ceiling of the cleanroom according to the required air volume for the cleanliness level. The cleanroom is equipped with a return air duct, and the return air inlet of the return air duct is connected to the air inlet side of the temperature control module, which is used to guide the return air from the cleanroom work area to the temperature control module. In the temperature control module, the coil is a copper tube with aluminum fins, the supply temperature of the medium-temperature water is 16-18℃ and the return temperature is 21-23℃, and the temperature control module does not have a condensate pan or drainage device. In the humidity and positive pressure control module, the fresh air handling unit is equipped with a surface cooling section and a reheating section. The surface cooling section uses low-temperature water as a refrigerant. The supply temperature of the low-temperature water is 6-8℃ and the return temperature is 12-14℃, which is used to treat the fresh air to the dew point state of the machine.

[0007] Furthermore, the fresh air handling unit also includes a variable frequency fan, which automatically adjusts its speed according to the feedback signal from the differential pressure sensor located at the entrance of the clean room, in order to maintain the positive pressure between the room and the outside at 10-15 Pa.

[0008] Furthermore, the cleanliness control module and the temperature control module are arranged in layers in the vertical space; The temperature control module is located in the upper static pressure box area of ​​the cleanliness control module, so that the return airflow first passes through the coil of the temperature control module for sensible heat exchange before entering the cleanliness control module.

[0009] Furthermore, it also includes a dual-temperature cold source system, which includes a first cold source for providing the low-temperature water and a second cold source for providing the medium-temperature water; The second cold source is at least one of a plate heat exchanger, a high-temperature chiller, or a natural cooling method.

[0010] According to another aspect of this application, a control method for an independently decoupled cleanroom air conditioning system is provided, comprising: S1. Activate the humidity and positive pressure control module to operate at an air volume 20-30% higher than the design air volume, and establish a positive pressure barrier in the cleanroom; S2. When the pressure difference reaches 1.5 times the set value, start the temperature control module, adjust the opening of the medium temperature water valve according to the feedback of the indoor temperature sensor, adjust the indoor temperature to the design value, and keep the surface temperature of the coil above the air dew point. S3. Synchronously start the cleanliness control module, so that the FFU unit in the cleanliness control module runs at the rated wind speed, and adjust the FFU speed according to the particle counter feedback of the working area to establish cleanliness. S4. The cleanliness control module, temperature control module, and humidity and positive pressure control module are controlled independently. The cleanliness control module maintains the circulating air volume to ensure cleanliness. The temperature control module adjusts the medium-temperature water flow rate according to the change of sensible heat load to maintain the temperature. The humidity and positive pressure control module adjusts the low-temperature water flow rate and reheat according to the indoor humidity sensor to maintain humidity, and adjusts the fresh air fan frequency according to the differential pressure sensor to maintain positive pressure.

[0011] Furthermore, in S4, when the indoor sensible heat load increases, only the opening of the water valve of the temperature control module is adjusted to increase the medium-temperature water flow rate, while the FFU air volume of the cleanliness control module remains unchanged. When the outdoor humidity increases, leading to an increase in indoor moisture load, only the low-temperature water flow rate and reheat of the humidity and positive pressure control module are adjusted, while the operating parameters of the temperature control module remain unchanged.

[0012] Furthermore, the cleanliness control module adopts a group control zoning strategy, independently adjusting the rotation speed of the FFU unit in the corresponding area based on the particle counter data of each area, thereby realizing differentiated control of cleanroom zones. The temperature control module and the humidity and positive pressure control module are adjusted uniformly according to the overall load of the cleanroom.

[0013] The beneficial effects that this application can produce include: The cleanroom air conditioning system and its control method provided in this application achieve independent and precise control of clean air supply, particulate control, sensible heat treatment, fresh air supply, and dehumidification and pressure stabilization through the triple decoupling operation of air volume, load, and control of three major modules: cleanliness, temperature, humidity, and positive pressure. The temperature control module uses medium-temperature water-cooled medium and maintains dry operation, which not only eliminates the risk of microbial growth and contamination of the clean environment by condensate, but also avoids energy waste caused by the cancellation of hot and cold air, significantly improving the accuracy and stability of temperature, humidity, and cleanliness control. At the same time, the fresh air volume and circulating air volume are independently calculated and matched, which can strictly guarantee the positive pressure of the cleanroom and the fresh air needs of personnel, while also optimizing the air volume configuration as needed, reducing system energy consumption and operating costs, and facilitating zoned control and maintenance, thus greatly improving the environmental reliability and overall energy efficiency of the cleanroom. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a cleanroom independent decoupled clean air conditioning system according to one embodiment of this application; Figure 2 This is a structural diagram of an independent decoupled cleanroom air conditioning system according to one embodiment of this application; Figure 3 This is a flowchart illustrating a control method for an independently decoupled cleanroom air conditioning system in one embodiment of this application; List of components and diagram labels: 1-Cleanliness control module; 2-Temperature control module; 3-Humidity and positive pressure control module; 4-Clean room; 5-Return air duct; 6-Technical interlayer. Detailed Implementation

[0015] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0016] See Figure 1-3 ,like Figure 1-2 As shown, a cleanroom independent decoupled air conditioning system includes: Cleanliness control module 1 is located on the upper part of the ceiling of cleanroom 4. It is responsible for clean air supply and particulate control in cleanroom 4, but does not participate in temperature and humidity control. Temperature control module 2 is located in the technical interlayer 6 inside the ceiling of clean room 4. Temperature control module 2 includes a coil for handling the sensible heat load in clean room 4. Medium-temperature water is used as the refrigerant and is introduced into the coil. The difference between the supply temperature of the medium-temperature water and the dew point temperature of the indoor air is set to be no less than 5°C, so that temperature control module 2 operates under dry conditions and the surface temperature of the coil is always higher than the dew point temperature of the indoor air. Humidity and positive pressure control module 3, including fresh air handling unit and air supply duct, is used to handle the fresh air load, latent heat load and positive pressure maintenance in clean room 4; The cleanliness control module 1, temperature control module 2, and humidity and positive pressure control module 3 achieve functional independence through air volume decoupling, load decoupling, and control decoupling. During steady-state operation, they work together to maintain the cleanliness, temperature, humidity, and positive pressure of the cleanroom environment. The circulating air volume of the cleanliness control module 1 is calculated according to the cleanliness requirements, and the fresh air volume of the humidity and positive pressure control module 3 is calculated based on the largest value among the sum of the positive pressure maintenance and compensation exhaust air volume, the dehumidification air volume, and the minimum fresh air volume for personnel. The fresh air volume and the circulating air volume are independent of each other.

[0017] Specifically, the cleanliness control module 1 is installed in the upper part of the ceiling of cleanroom 4. It is responsible for the clean air supply and the control of airborne particles within cleanroom 4. It does not participate in any temperature or humidity control, aiming to ensure the specificity of cleanliness control and avoid the impact of airflow disturbances, condensation, and other factors on cleanliness during temperature and humidity control. Simultaneously, it can flexibly adjust the air supply parameters according to cleanliness requirements to ensure that cleanroom 4 reaches the preset cleanliness level. The temperature control module 2 is installed in the technical interlayer 6 within the ceiling of cleanroom 4, specifically as a coil. It mainly bears the sensible heat load within cleanroom 4, i.e., loads that only change the air temperature without changing the air humidity, such as equipment heat dissipation and personnel heat dissipation. This module uses medium-temperature water as the refrigerant supplied to the coil. The difference between the medium-temperature water supply temperature and the indoor air dew point temperature is not less than 2~5℃, allowing the temperature control... Module 2 operates under dry conditions, with the coil surface temperature always higher than the dew point temperature of the indoor air. This prevents moisture in the air from condensing on the coil surface, reducing the risk of bacteria growth and contamination of cleanroom 4. It also lowers system maintenance costs and improves operational stability. Module 3, consisting of a fresh air handling unit and air supply ducts, serves three purposes: first, it handles the fresh air load by introducing fresh outdoor air to replace stale indoor air and ensure indoor air quality; second, it handles the latent heat load by changing the air humidity content and regulating indoor humidity, such as removing excess moisture to prevent excessive humidity in cleanroom 4 from causing equipment malfunctions or product dampness; and third, it maintains positive pressure in cleanroom 4 to prevent unfiltered polluted outdoor air from entering through door and window gaps, equipment interfaces, etc., and damaging the clean environment.

[0018] It is worth noting that the three modules work together through three methods: air volume decoupling, load decoupling, and control decoupling, so that they can operate independently without interfering with each other, while jointly ensuring that the various indicators of cleanroom 4 meet the standards. The circulating air volume of the cleanliness control module 1 is calculated solely based on the cleanliness level requirements of cleanroom 4. The fresh air volume of the humidity and positive pressure control module 3 must simultaneously meet three conditions and take the maximum value: the air volume required to maintain positive pressure in cleanroom 4 to offset indoor exhaust and air leakage; the air volume required for dehumidification calculated based on the indoor latent heat load; and the minimum fresh air volume for personnel to ensure the amount of fresh air needed for breathing. The air volume calculations for both modules are completely independent and do not affect each other, avoiding the problem of sacrificing one indicator to meet another in traditional systems. The cleanliness control module 1 only handles particulate control load, the temperature control module 2 only handles sensible heat load, and the humidity and positive pressure control module 3 only handles fresh air, latent heat, and positive pressure load. These three types of loads are independent of each other, eliminating the need for one module to handle multiple loads, thus improving control accuracy and operating efficiency. Each of the three modules uses independent control logic and control equipment, and can adjust in real time according to its own responsible indicators without mutual linkage or waiting, further improving the system's response speed and control stability.

[0019] The cleanliness control module 1 includes multiple FFU units, which are arranged in the ceiling of the cleanroom according to the required air volume for the cleanliness level. The cleanroom 4 is provided with a return air duct 5, and the return air inlet of the return air duct 5 is connected to the air inlet side of the temperature control module 2, which is used to guide the return air of the working area of ​​the cleanroom 4 to the temperature control module 2. In the temperature control module 2, the coil is a copper tube with aluminum fins, the supply temperature of the medium-temperature water is 16-18℃ and the return temperature is 21-23℃, and the temperature control module 2 does not have a condensate pan or drainage device. In the humidity and positive pressure control module 3, the fresh air handling unit is equipped with a surface cooling section and a reheating section. The surface cooling section uses low-temperature water as a refrigerant. The supply temperature of the low-temperature water is 6-8℃ and the return temperature is 12-14℃, which is used to treat the fresh air to the dew point state of the machine.

[0020] Specifically, the cleanliness control module 1 consists of multiple FFU (Fan-Filter Unit) units, which are arranged to fully cover the cleanroom ceiling according to the required air volume for the cleanliness level. FFU units are commonly used cleanroom air supply devices in cleanroom 4, equipped with their own fans and HEPA filters, and can directly supply clean air to cleanroom 4. Their full-coverage arrangement ensures uniform air supply to all areas of cleanroom 4, avoiding cleanliness dead zones. Furthermore, the start / stop and speed adjustment of individual FFUs can flexibly adapt to the cleanliness requirements of different areas, ensuring that the cleanliness of the entire cleanroom 4 meets the standards.

[0021] The coil in temperature control module 2 adopts a copper tube and aluminum fin structure, which has high heat transfer efficiency, corrosion resistance, and small size. It is suitable for installation in the technical interlayer 6 within the ceiling and can quickly achieve sensible heat exchange to meet the response requirements of temperature regulation. The supply temperature of medium-temperature water is 16-18℃, and the return temperature is 21-23℃. This temperature range ensures that the surface temperature of the coil is higher than the dew point temperature of the indoor air, avoiding condensation, and can efficiently remove the sensible heat load of the room, achieving precise temperature control. At the same time, medium-temperature water in this temperature range can be prepared in a more energy-efficient way, such as using waste heat or natural cooling, reducing system energy consumption. Furthermore, temperature control module 2 does not have a condensate pan or drainage device. Since no condensate will be generated on the surface of the coil, there is no need to install a condensate pan and drainage pipe. This not only simplifies the system structure and reduces installation costs, but also avoids problems such as water accumulation in the condensate pan leading to bacterial growth and drainage pipe blockage, further ensuring the clean environment of clean room 4. Optionally, a stainless steel condensate pan and drainage device can be installed for emergency drainage in special circumstances. In the humidity and positive pressure control module 3, the fresh air handling unit is equipped with a cooling section and a reheating section. The cooling section uses low-temperature water as the refrigerant, with a supply temperature of 6-8℃ and a return temperature of 12-14℃, treating the fresh air to the machine's dew point. The machine's dew point refers to the temperature at which water vapor in the air begins to condense after the fresh air has been cooled by the cooling section. Treating the fresh air to the machine's dew point maximizes the removal of water vapor from the fresh air, ensuring that the humidity of the fresh air entering the cleanroom 4 meets the standards. The reheating section heats the treated low-temperature fresh air to a suitable temperature, preventing temperature fluctuations in the cleanroom 4 caused by the low-temperature fresh air entering, while further improving the cleanliness of the fresh air. The high temperature also inhibits bacterial growth. The low-temperature water supply is 7-8℃, and the return temperature is 12-14℃, ensuring the cooling efficiency of the cooling section and quickly achieving dehumidification of the fresh air.

[0022] The fresh air handling unit also includes a variable frequency fan, which automatically adjusts its speed according to the feedback signal from the differential pressure sensor located at the entrance of the clean room 4, in order to maintain the positive pressure between the room and the outside at 10-15 Pa.

[0023] Specifically, the fresh air handling unit is equipped with a variable frequency fan, which can flexibly adjust its speed according to actual needs, thereby regulating the fresh air supply volume, achieving energy-saving operation and precise control. When the positive pressure reaches the standard, the fan operates at low speed; when the positive pressure is insufficient, the fan speeds up to supplement the fresh air volume. The speed adjustment of the variable frequency fan is automatically controlled by the signal feedback from the differential pressure sensor located at the entrance of cleanroom 4. The differential pressure sensor detects the pressure difference between cleanroom 4 and the outside in real time and transmits the detected pressure difference signal to the control system. The control system compares the actual pressure difference with the set pressure difference. If the actual pressure difference is lower than the set value, it controls the variable frequency fan to increase its speed, increase the fresh air supply volume, and increase the indoor positive pressure; if the actual pressure difference is higher than the set value, it controls the fan to decrease its speed, reduce the fresh air supply volume, and ensure that the positive pressure is stable within the set range. The indoor positive pressure to the outside is set to 10-15 Pa. If the positive pressure is too low, it cannot effectively block the entry of polluted outdoor air, damaging the clean environment; if the positive pressure is too high, it will make it difficult to open the doors and windows of cleanroom 4, increase energy loss, and may even cause indoor airflow turbulence, affecting the cleanliness. The positive pressure setting in this application can ensure the sealing performance of cleanroom 4, while also taking into account the energy efficiency and operational stability of the system.

[0024] The cleanliness control module 1 and the temperature control module 2 are arranged in layers in the vertical space; The temperature control module 2 is located in the upper static pressure box area of ​​the cleanliness control module 1, so that the return airflow first passes through the coil of the temperature control module 2 for sensible heat exchange before entering the cleanliness control module 1.

[0025] Specifically, the two modules are arranged vertically in layers, with temperature control module 2 located in the upper static pressure box area above cleanliness control module 1. The static pressure box is an enclosed space above the ceiling of cleanroom 4, whose main function is to stabilize airflow and evenly distribute air volume. Placing temperature control module 2 inside the static pressure box can make full use of the space advantage of the static pressure box, avoid structural conflicts between the two modules, and optimize the airflow path. The return airflow first passes through the coil of temperature control module 2 for sensible heat exchange before entering cleanliness control module 1. Specifically, the return air in cleanroom 4 first rises to the static pressure box above the ceiling, passes through the coil of temperature control module 2, removes heat from the return air through sensible heat exchange, and lowers the return air temperature. Then, the cooled return air enters cleanliness control module 1, is filtered by the FFU unit, and is then sent into cleanroom 4 as clean air at a suitable temperature. This layered layout and airflow path design, where the return air undergoes temperature treatment first, reduces the temperature load on the cleanliness control module 1, avoids the FFU unit from simultaneously undertaking temperature regulation tasks while delivering air, further enhances the decoupling effect, and improves the operating efficiency of both modules; at the same time, the temperature-regulated return air then enters the FFU filter, which can prevent high-temperature return air from affecting the performance of the FFU filter, while ensuring that the air delivered to cleanroom 4 is both clean and meets the temperature standards, thus improving the stability of the cleanroom 4 environment.

[0026] It also includes a dual-temperature cold source system, which includes a first cold source for providing the low-temperature water and a second cold source for providing the medium-temperature water; The second cold source is at least one of a plate heat exchanger, a high-temperature chiller, or a natural cooling method.

[0027] Specifically, the system provides two different temperatures of chilled water: low-temperature water for the surface cooling section of the humidity and positive pressure control module 3, and medium-temperature water for the coil of the temperature control module 2. These meet the different cooling needs of the two modules, avoiding the problem that a single cold source cannot meet the two temperature requirements, while also improving the energy efficiency of the system.

[0028] The first cold source is specifically designed to provide low-temperature water, primarily supplying refrigerant to the surface cooling section of the humidity and positive pressure control module 3 for dehumidifying the fresh air. Its cooling capacity and temperature accuracy must meet the requirements of fresh air dehumidification, and a conventional chiller unit can typically be used. The second cold source is specifically designed to provide medium-temperature water, supplying refrigerant to the coils of the temperature control module 2 for handling indoor sensible heat load. This claim specifies the optional types of the second cold source, including at least one of plate heat exchangers, high-temperature chiller units, or natural cooling methods. Plate heat exchangers can utilize industrial waste heat, residual heat, or other low-grade heat energy to heat chilled water to the medium-temperature range, achieving energy recovery and significantly reducing energy consumption, making them suitable for cleanrooms with waste heat resources. High-temperature chiller units are specifically designed for producing medium-temperature chilled water, with high operating efficiency and precise temperature control, suitable for scenarios without waste heat resources and requiring high temperature accuracy. In seasons with low outdoor temperatures, outdoor cold air can be used to directly cool the chilled water without starting the refrigeration unit, further reducing energy consumption and achieving energy-saving operation.

[0029] Example 1: The independent decoupled clean air conditioning system of a certain ISO5 cleanroom adopts the design concept of three independent subsystems operating in coordination, including cleanliness control module 1, temperature control module 2 and humidity and positive pressure control module 3.

[0030] The cleanliness control module 1 of the independent decoupled cleanroom air conditioning system is located in the upper part of the ceiling of cleanroom 4. It primarily handles clean air supply and particulate control within cleanroom 4, and does not participate in temperature and humidity control. This module includes multiple FFU units, and the air supply volume required for ISO Class 5 cleanliness is fully distributed throughout the cleanroom ceiling. In this system, the average unidirectional flow cross-sectional velocity is taken as 0.35 m / s, and the circulating air volume is 756,000 m³ / s. 3 / h, using EC motor FFU with specifications of 1200×1200mm, single unit air volume 2100m³ / h. 3A total of 360 units are required per hour. The FFU coverage rate is calculated to be 86.4%, the air velocity is 0.35 m / s, the filter grade is H14, and a group control system with independent speed adjustment in 6 zones is adopted.

[0031] Temperature control module 2 is located in the technical mezzanine 6 within the ceiling of cleanroom 4, and includes a coil to handle the sensible heat load within cleanroom 4. This module uses medium-temperature water as the refrigerant, with the supply temperature of the medium-temperature water and the dew point temperature of the indoor air set at no less than 5℃ to ensure that temperature control module 2 operates under dry conditions, with the coil surface temperature always higher than the indoor air dew point temperature. The coil uses a copper tube and aluminum fin structure. The supply temperature of the medium-temperature water is 16-18℃, and the return temperature is 21-23℃. Temperature control module 2 does not have a condensate pan or drainage device. In this system, the sensible heat load is 180kW; considering a safety factor of 1.2, the design load is 216kW. Using 16 / 21℃ medium-temperature water with a temperature rise of 5℃, the calculated water flow rate is approximately 37m³ / h. 3 / h, using 8 dry cooling coils, each with a sensible cooling capacity of 27kW and an air volume of 27000m³ / h. 3 / h. After verification, the dew point of the indoor unit at 22℃ / 50%RH is 11.1℃, the inlet water temperature of the coil is 16℃, the surface temperature is about 17-18℃, and the safety margin is greater than 6℃ to ensure no condensation.

[0032] The humidity and positive pressure control module 3 includes a fresh air handling unit and air supply ducts, used to handle the fresh air load, latent heat load, and maintain positive pressure within cleanroom 4. The fresh air handling unit has a cooling section and a reheat section. The cooling section uses low-temperature water as the refrigerant, with a supply temperature of 7-8℃ and a return temperature of 12-14℃, used to treat the fresh air to the machine's dew point. The fresh air handling unit also includes a variable frequency fan, which automatically adjusts its speed based on feedback signals from a differential pressure sensor located at the entrance of cleanroom 4, used to maintain a positive pressure of 10-15 Pa. In this system, the fresh air volume is calculated based on the largest value among the sum of maintaining positive pressure and compensating exhaust air volume, dehumidification air volume, and minimum fresh air volume for personnel; the designed fresh air volume is 9500 m³ / h. 3 / h (with a design safety margin of 1.1 times). The fresh air unit is equipped with a variable frequency fan, with an air volume range of 5000-12000m³ / h. 3 / h, with primary filter G4, medium filter F8 and high filter H13, the surface cooling section uses 6 / 12℃ low temperature water, 8 rows of pipes, which can treat fresh air to 11℃ / 95%RH, with a moisture content of 7.9g / kg. The reheat section uses electric heating or hot water reheating to raise the supply air temperature to 18℃ and send it to the ceiling static pressure box.

[0033] The cleanliness control module 1 and the temperature control module 2 are arranged in layers in the vertical space. The temperature control module 2 is located in the upper static pressure box area of ​​the cleanliness control module 1, so that the return airflow first passes through the coil of the temperature control module 2 for sensible heat exchange before entering the cleanliness control module 1.

[0034] The system also includes a dual-temperature cold source system, comprising a primary cold source for providing low-temperature water and a secondary cold source for providing medium-temperature water. The secondary cold source can be at least one of a plate heat exchanger, a high-temperature chiller, or natural cooling. In this system, the primary cold source uses a conventional chiller to provide 7 / 12°C low-temperature water for the fresh air unit and reheat cold source, with a load of approximately 120kW. The secondary cold source utilizes the 12°C return water from the primary cold source via a plate heat exchanger, or uses an independent high-temperature chiller to produce 16 / 21°C medium-temperature water for dry coils, with a load of 216kW. If natural cooling is used, 16°C medium-temperature water can be directly produced using a cooling tower during winter and transitional seasons, at which point the energy consumption of the secondary cold source is close to zero.

[0035] The cleanroom's independently decoupled cleanroom air conditioning system comprises a cleanliness control module 1, a temperature control module 2, and a humidity and positive pressure control module 3, which operate collaboratively through airflow decoupling, load decoupling, and control decoupling. Specifically, the circulating airflow of the cleanliness control module 1 is calculated based on cleanliness requirements, while the fresh airflow of the humidity and positive pressure control module 3 is calculated as the largest of the sum of maintaining positive pressure and compensating exhaust airflow, the dehumidification airflow, and the minimum fresh airflow for personnel. The fresh airflow and circulating airflow are independent of each other.

[0036] In a preferred embodiment, for locations requiring higher biosafety, such as Class A filling areas in biopharmaceutical manufacturing, the FFU can use a U15-grade ULPA filter. To prevent any microbial risks, the dry coil uses stainless steel fins, and the coil housing has an antibacterial coating. In addition to temperature and humidity control, the fresh air system is equipped with terminal high-efficiency filtration to ensure that the fresh air entering the clean room 4 meets Class A standards. The control logic adds interlock protection between the FFU operating status and differential pressure to ensure that the fresh air system automatically increases the air volume to maintain positive pressure in the event of any FFU failure.

[0037] Actual measurements show that the independent decoupled clean air conditioning system in this cleanroom reduces annual energy consumption by 32% compared to the traditional single-pass return air system, and reduces peak summer load by 28%; indoor temperature control accuracy reaches ±0.5℃, and humidity ±2%RH; after 12 months of continuous operation, there is no condensation or leakage in the dry coil area; the positive pressure is stable at 12±2Pa, and the cleanliness level continuously meets ISO 5 requirements.

[0038] like Figure 2 As shown, a control method for an independently decoupled cleanroom air conditioning system includes: S1. Activate humidity and positive pressure control module 3 to operate at an air volume 20-30% higher than the design air volume, and establish a positive pressure barrier in the cleanroom 4. S2. When the pressure difference reaches 1.5 times the set value, start the temperature control module 2, adjust the opening of the medium temperature water valve according to the feedback of the indoor temperature sensor, adjust the indoor temperature to the design value, and keep the surface temperature of the coil higher than the air dew point. S3. Simultaneously start the cleanliness control module 1, so that the FFU unit in the cleanliness control module 1 runs at the rated wind speed, and adjusts the FFU speed according to the particle counter feedback of the working area to establish cleanliness. S4. The cleanliness control module 1, temperature control module 2, and humidity and positive pressure control module 3 are controlled independently. The cleanliness control module 1 maintains the circulating air volume to ensure cleanliness. The temperature control module 2 adjusts the medium-temperature water flow rate according to the change of sensible heat load to maintain temperature. The humidity and positive pressure control module 3 adjusts the low-temperature water flow rate and reheat according to the indoor humidity sensor to maintain humidity, and adjusts the fresh air fan frequency according to the differential pressure sensor to maintain positive pressure.

[0039] Specifically, during the startup phase, the primary task is to establish a positive pressure barrier in cleanroom 4 to prevent polluted outdoor air from entering. Therefore, the humidity and positive pressure control module 3 is activated first, and the fresh air handling unit is operated at an airflow 20-30% higher than the design airflow. This is because there is no positive pressure in cleanroom 4 at the initial startup stage, and it is necessary to increase the fresh air volume to quickly fill the room, rapidly increase the indoor pressure, and shorten the time required to establish positive pressure. At the same time, the excess fresh air can also quickly replace the polluted air in the room, laying the foundation for subsequent temperature and cleanliness adjustments. When the pressure difference in cleanroom 4 reaches 1.5 times the set value, it indicates that the positive pressure barrier has been initially established. At this time, the temperature control module 2 is activated to avoid airflow turbulence affecting the positive pressure during temperature adjustment. An indoor temperature sensor monitors the indoor temperature in real time and transmits the signal to the control system. The control system compares the actual temperature with the design temperature. If the actual temperature is higher than the design value, the opening of the medium-temperature water valve is increased to increase the flow rate of medium-temperature water, thereby improving the sensible heat exchange efficiency of the coil and quickly lowering the indoor temperature. If the actual temperature is lower than the design value, the opening of the water valve is decreased to reduce the flow rate of medium-temperature water, thereby reducing the sensible heat exchange efficiency and raising the indoor temperature. Simultaneously, throughout the entire adjustment process, the surface temperature of the coil must always be kept higher than the dew point temperature of the indoor air to maintain dry operation and prevent condensation. Simultaneously with the activation of the temperature control module 2, the cleanliness control module 1 is also activated to achieve synchronous adjustment of temperature and cleanliness, shortening system startup time. The FFU unit initially operates at its rated fan speed, quickly delivering a large amount of clean air to the cleanroom 4 to initially establish a clean environment. A particle counter in the working area monitors the concentration of airborne particles in real time and transmits the signal to the control system. If the particle concentration is higher than the set value, the FFU speed is increased to increase the circulating air volume and accelerate the filtration and removal of particles. If the particle concentration is lower than the set value, the FFU speed is appropriately reduced to save energy, ultimately maintaining the cleanliness within the design requirements.

[0040] It is worth noting that the cleanliness control module 1 maintains the circulating air volume to ensure that the cleanliness meets the standards, and adjusts the FFU speed in real time based on the feedback from the particle counter, without considering changes in temperature and humidity; the temperature control module 2 maintains a stable indoor temperature, and adjusts the medium-temperature water flow rate in real time based on changes in the indoor sensible heat load, without intervening in cleanliness and humidity control, ensuring a rapid response in temperature regulation; the humidity and positive pressure control module 3 adjusts the low-temperature water flow rate of the cooling section and the reheating heat of the reheat section based on the humidity value fed back by the indoor humidity sensor to maintain the indoor humidity meeting the standards; and adjusts the frequency of the fresh air fan and changes the fresh air supply volume based on the differential pressure signal fed back by the differential pressure sensor to maintain the positive pressure between the indoor and outdoor environments within the range of 10-15Pa.

[0041] In S4, when the indoor sensible heat load increases, only the opening of the water valve of the temperature control module 2 is adjusted to increase the medium-temperature water flow, while the FFU air volume of the cleanliness control module 1 remains unchanged. When the outdoor humidity increases, leading to an increase in indoor moisture load, only the low-temperature water flow rate and reheat of the humidity and positive pressure control module 3 are adjusted, while the operating parameters of the temperature control module 2 remain unchanged.

[0042] Specifically, when the indoor sensible heat load increases, only the water valve opening of temperature control module 2 is adjusted to increase the medium-temperature water flow. This increased flow improves the sensible heat exchange efficiency of the coils, quickly removing the additional sensible heat load and maintaining the indoor temperature at the design value. Meanwhile, the FFU airflow of cleanliness control module 1 remains unchanged. Because changes in sensible heat load are unrelated to cleanliness, there is no need to adjust the FFU speed, avoiding fluctuations in cleanliness due to airflow changes and saving energy. Changes in sensible heat load only affect the indoor temperature, not the air humidity or particulate concentration. Therefore, only temperature control module 2 needs to respond independently, achieving load decoupling and control decoupling, avoiding the problem of cleanliness being affected when adjusting temperature in traditional systems. When outdoor humidity increases, leading to an increase in indoor moisture load, only the low-temperature water flow rate and reheat capacity of the humidity and positive pressure control module 3 need to be adjusted. Increasing the low-temperature water flow rate can improve the dehumidification efficiency of the surface cooling section and remove excess moisture from the fresh air. Adjusting the reheat capacity can heat the dehumidified low-temperature fresh air to a suitable temperature, preventing the indoor temperature from dropping due to dehumidification. The operating parameters of the temperature control module 2 remain unchanged because the change in moisture load is unrelated to the indoor sensible heat load, so there is no need to adjust the temperature control module 2, ensuring a stable indoor temperature. At the same time, it avoids interference with humidity control due to temperature adjustment. The change in moisture load only affects indoor humidity and does not affect indoor temperature and cleanliness. Therefore, only the humidity and positive pressure control module 3 needs to respond independently to ensure that the control of each indicator does not interfere with each other, thereby improving the stability and control accuracy of the system.

[0043] The cleanliness control module 1 adopts a group control zoning strategy, which independently adjusts the rotation speed of the FFU unit in the corresponding area according to the particle counter data of each area, so as to realize the differentiated control of the cleanroom 4 zones. The temperature control module 2 and the humidity and positive pressure control module 3 are adjusted uniformly according to the overall load of the clean room 4.

[0044] Specifically, the cleanliness requirements of different areas within a cleanroom may vary. Therefore, the cleanliness control module 1 adopts a group control zoning strategy, dividing the cleanroom 4 into multiple independent areas. Each area is equipped with an independent particle counter and FFU unit group. The control system independently adjusts the FFU unit speed of the corresponding area based on the data fed back from the particle counters in each area. In areas with high cleanliness requirements, the FFU speed is maintained at a higher level to ensure that the particle concentration meets the standards. In areas with lower cleanliness requirements, the FFU speed can be appropriately reduced to save energy. Through differentiated zoning control, the cleanliness requirements of different areas are met, energy waste is avoided, and the system can flexibly adapt to changes in production conditions in each area, improving the energy efficiency and flexibility of the system. Unlike cleanliness control, indoor temperature and humidity are holistic. The temperature and humidity of each area within the cleanroom 4 affect each other, making independent zoning control difficult. Therefore, these two modules are uniformly adjusted according to the overall load of cleanroom 4. Temperature control module 2 adjusts the medium-temperature water flow rate based on the average feedback values ​​of multiple temperature sensors in cleanroom 4 and the overall sensible heat load to ensure that the temperature of the entire cleanroom 4 is uniform and meets the standard, avoiding excessive temperature differences between areas. Humidity and positive pressure control module 3 adjusts the low-temperature water flow rate and reheat capacity based on the average feedback values ​​of multiple humidity sensors in cleanroom 4 and the overall latent heat load. At the same time, based on the feedback from the differential pressure sensor at the entrance of cleanroom 4, it uniformly adjusts the fresh air fan frequency to maintain the positive pressure stability of the entire cleanroom 4 and ensure that the humidity and positive pressure of each area meet the standards. The overall adjustment strategy adapts to the overall characteristics of temperature and humidity, ensuring the uniformity of the cleanroom 4 environment. At the same time, the overall adjustment simplifies the control logic, reduces the complexity of the control system, and improves the stability and reliability of system operation.

[0045] Example 2: A control method for an independently decoupled cleanroom air conditioning system in a Class A filling area cleanroom for biopharmaceutical manufacturing, applied to an ISO 5 cleanroom with dimensions of 30m × 20m × 3m and a volume of 1800m³. 3 The design temperature is 23±1℃, and the design humidity is 50±5%RH. The method includes the following steps: S1. Activate humidity and positive pressure control module 3, operating at an airflow 20-30% higher than the design airflow to establish a positive pressure barrier in the cleanroom 4. Specifically, this module operates at 9500m... 3 Operating at an airflow rate of / h, it quickly establishes a positive pressure of 10Pa and maintains it for 30 minutes to ensure that cleanroom 4 forms an effective airflow barrier between itself and the external environment.

[0046] S2. When the pressure difference reaches 1.5 times the set value, the temperature control module 2 is activated. Based on the feedback from the indoor temperature sensor, the opening of the medium-temperature water valve is adjusted to bring the indoor temperature to the design value, and the surface temperature of the coil is always higher than the air dew point. In this embodiment, when the pressure difference reaches 15Pa, the dry cooling coil is activated, and the water valve starts from 50% opening. Based on the PID adjustment according to the temperature sensor feedback, the indoor temperature is adjusted to 23℃. The coil uses 16 / 21℃ medium-temperature water, and the surface temperature of the coil is maintained at 17-18℃, which is much higher than the dew point temperature of 10.2℃ under the indoor conditions of 22℃ / 45%RH, ensuring no risk of condensation. To meet the high standard requirements of the biopharmaceutical Grade A area, the dry coil uses stainless steel fins, and the coil housing is coated with an antibacterial coating to prevent any microbial risks.

[0047] S3. Simultaneously start the cleanliness control module 1, causing the FFU unit in the cleanliness control module 1 to operate at the rated airflow speed. Adjust the FFU speed according to the particle counter feedback of the working area to establish the cleanliness level. The cleanliness control module 1 uses EC motor FFUs with specifications of 1200×1200mm and a single unit airflow of 2100m³ / h. 3 With a capacity of 360 units per hour, the FFU coverage rate reaches over 95%, far exceeding the requirements of conventional cleanrooms. This meets the stringent standards of the biopharmaceutical Class A filling area. The FFUs use U15 grade ULPA filters, with an efficiency of ≥99.9995% for 0.12μm particles, ensuring compliance with Class A cleanliness requirements.

[0048] S4. The cleanliness control module 1, temperature control module 2, and humidity and positive pressure control module 3 are controlled independently. Among them, the cleanliness control module 1 maintains the circulating air volume to ensure cleanliness, the temperature control module 2 adjusts the medium-temperature water flow rate according to the change of sensible heat load to maintain temperature, and the humidity and positive pressure control module 3 adjusts the low-temperature water flow rate and reheat according to the indoor humidity sensor to maintain humidity, and adjusts the fresh air fan frequency according to the differential pressure sensor to maintain positive pressure.

[0049] When the indoor sensible heat load increases, only the water valve opening of temperature control module 2 is adjusted to increase the medium-temperature water flow rate, while the FFU air volume of cleanliness control module 1 remains unchanged. For example, when the process equipment load increases from 120kW to 150kW, temperature control module 2 automatically increases the medium-temperature water flow rate from 37m³ / h. 3 / h to 45m 3 / h, while the FFU air volume remains constant to ensure that the cleanliness is not affected.

[0050] When increased outdoor humidity leads to increased indoor moisture load, only the low-temperature water flow rate and reheat capacity of the humidity and positive pressure control module 3 are adjusted, while the operating parameters of the temperature control module 2 remain unchanged. For example, when the outdoor humidity rises from 25.8℃ wet-bulb temperature to 28℃ wet-bulb temperature, the fresh air unit automatically increases the 7 / 12℃ low-temperature water flow rate and adjusts the reheat capacity accordingly to control the moisture content of the supply air below 7.8g / kg, while the medium-temperature water flow rate and temperature of the temperature control module 2 remain unchanged.

[0051] Cleanliness control module 1 adopts a group control zoning strategy, independently adjusting the FFU unit speed of the corresponding zone based on the particle counter data of each zone to achieve differentiated control of the cleanroom in four zones. In specific implementation, the entire filling area is divided into 6 independent control zones, each equipped with a 0.5μm particle counter. When the particle count in a certain zone approaches the limit, the FFU speed in that zone automatically increases by 5-10% until the particle count drops to a safe level; when the particle count remains below 50% of the limit, the FFU speed can be appropriately reduced to save energy.

[0052] Temperature control module 2 and humidity and positive pressure control module 3 are uniformly adjusted according to the overall load of clean room 4. Temperature control module 2 performs PID adjustment based on the average value of multiple temperature sensors in the room to control the temperature within the range of 24±0.5℃. Humidity and positive pressure control module 3 controls the humidity at 45±2%RH and the pressure difference at 12±2Pa based on the data from the indoor humidity sensor and differential pressure sensor.

[0053] In addition, the control logic incorporates interlocking protection between FFU operating status and differential pressure, ensuring that the fresh air system automatically increases airflow to maintain positive pressure in the event of any FFU failure. When any FFU failure is detected, the system automatically increases the fresh air fan frequency by 10% to maintain positive pressure at a safe level, while simultaneously triggering an alarm to prompt maintenance personnel to handle the situation promptly. Besides temperature and humidity control, the fresh air system also includes terminal high-efficiency filters to ensure that the fresh air entering cleanroom 4 meets Class A standards.

[0054] After the implementation of this control method, the temperature control accuracy of the biopharmaceutical Class A filling area reached ±0.5℃, the humidity was ±2%RH, the positive pressure was stable at 12±2Pa, the cleanliness continuously met the Class A requirements, the annual operating energy consumption was reduced by 32% compared with the traditional single-pass return air system, and the peak load in summer was reduced by 28%.

[0055] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A cleanroom independent decoupled air conditioning system, characterized in that, include: The cleanliness control module (1) is located on the ceiling of the clean room (4) and is used to handle the clean air supply and particulate control in the clean room (4), but does not participate in temperature and humidity control. Temperature control module (2) is located in the technical interlayer (6) inside the ceiling of clean room (4). The temperature control module (2) includes a coil for handling the sensible heat load in clean room (4). Medium-temperature water is used as a refrigerant and is introduced into the coil. The difference between the supply temperature of the medium-temperature water and the dew point temperature of the indoor air is set to be no less than 5°C, so that the temperature control module (2) operates under dry conditions and the surface temperature of the coil is always higher than the dew point temperature of the indoor air. The humidity and positive pressure control module (3), including the fresh air handling unit and the air supply duct, is used to handle the fresh air load, latent heat load and positive pressure maintenance in the clean room (4); The cleanliness control module (1), temperature control module (2), and humidity and positive pressure control module (3) achieve functional independence through air volume decoupling, load decoupling, and control decoupling, and work together to maintain the cleanliness, temperature, humidity, and positive pressure of the cleanroom environment during steady-state operation; wherein, the circulating air volume of the cleanliness control module (1) is calculated according to the cleanliness requirements, and the fresh air volume of the humidity and positive pressure control module (3) is calculated based on the maximum value of the sum of the positive pressure maintenance and compensation exhaust air volume, the dehumidification air volume, and the minimum fresh air volume for personnel, and the fresh air volume and the circulating air volume are independent of each other.

2. The cleanroom independent decoupled clean air conditioning system according to claim 1, characterized in that, The cleanliness control module (1) includes multiple FFU units, which are arranged in the ceiling of the cleanroom according to the required air supply volume for the cleanliness level. The cleanroom (4) is provided with a return air duct (5), and the return air inlet of the return air duct (5) is connected to the air inlet side of the temperature control module (2) to guide the return air of the working area of ​​the cleanroom (4) to the temperature control module (2). In the temperature control module (2), the coil is a copper tube with aluminum fins, the supply temperature of the medium-temperature water is 16-18℃ and the return temperature is 21-23℃, and the temperature control module (2) does not have a condensate pan and a drainage device. In the humidity and positive pressure control module (3), the fresh air handling unit is provided with a surface cooling section and a reheating section. The surface cooling section uses low-temperature water as a refrigerant. The supply temperature of the low-temperature water is 6-8℃ and the return temperature is 12-14℃, which is used to treat the fresh air to the dew point state of the machine.

3. The cleanroom independent decoupled clean air conditioning system according to claim 1, characterized in that, The fresh air handling unit also includes a variable frequency fan, which automatically adjusts its speed according to the feedback signal from the differential pressure sensor located at the entrance of the clean room (4) to maintain the positive pressure between the room and the outside at 10-15 Pa.

4. The cleanroom independent decoupled clean air conditioning system according to claim 1, characterized in that, The cleanliness control module (1) and the temperature control module (2) are arranged in layers in the vertical space; The temperature control module (2) is located in the upper static pressure box area of ​​the cleanliness control module (1), so that the return airflow first passes through the coil of the temperature control module (2) for sensible heat exchange before entering the cleanliness control module (1).

5. A cleanroom independent decoupled clean air conditioning system according to claim 1, characterized in that, It also includes a dual-temperature cold source system, which includes a first cold source for providing the low-temperature water and a second cold source for providing the medium-temperature water; The second cold source is at least one of a plate heat exchanger, a high-temperature chiller, or a natural cooling method.

6. A control method for an independently decoupled cleanroom air conditioning system, characterized in that, include: S1. Start the humidity and positive pressure control module (3) and run it with an air volume 20-30% higher than the design air volume to establish a positive pressure barrier in the clean room (4); S2. When the pressure difference reaches 1.5 times the set value, start the temperature control module (2), adjust the opening of the medium temperature water valve according to the feedback of the indoor temperature sensor, adjust the indoor temperature to the design value, and keep the surface temperature of the coil higher than the air dew point. S3. Simultaneously start the cleanliness control module (1) so that the FFU unit in the cleanliness control module (1) runs at the rated wind speed and adjusts the FFU speed according to the feedback of the particle counter in the working area to establish cleanliness. S4. The cleanliness control module (1), temperature control module (2), and humidity and positive pressure control module (3) are controlled independently. The cleanliness control module (1) maintains the circulating air volume to ensure cleanliness. The temperature control module (2) adjusts the medium-temperature water flow rate according to the change of sensible heat load to maintain temperature. The humidity and positive pressure control module (3) adjusts the low-temperature water flow rate and reheat according to the indoor humidity sensor to maintain humidity, and adjusts the fresh air fan frequency according to the differential pressure sensor to maintain positive pressure.

7. The control method for an independently decoupled cleanroom air conditioning system according to claim 6, characterized in that, In S4, when the indoor sensible heat load increases, only the water valve opening of the temperature control module (2) is adjusted to increase the medium temperature water flow rate, while the FFU air volume of the cleanliness control module (1) remains unchanged. When the outdoor humidity increases, leading to an increase in indoor moisture load, only the low-temperature water flow rate and reheat of the humidity and positive pressure control module (3) are adjusted, while the operating parameters of the temperature control module (2) remain unchanged.

8. The control method for an independently decoupled cleanroom air conditioning system according to claim 6, characterized in that, The cleanliness control module (1) adopts a group control zoning strategy, and independently adjusts the rotation speed of the FFU unit in the corresponding area according to the particle counter data of each area to realize the zoned differential control of the cleanroom (4). The temperature control module (2) and the humidity and positive pressure control module (3) are adjusted uniformly according to the overall load of the clean room (4).

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