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Technical Analysis of Clean Air Conditioning Control System
2025/4/25
The clean air conditioning control system is specifically applied to the purification air conditioning systems of clean workshops, microelectronics workshops, semiconductor workshops, GMP, biopharmaceutical enterprises, chemical clean workshops and other industries. It can achieve automatic regulation of system temperature and humidity, pressure difference, dew point, air volume and air velocity, as well as various safety protection, interlocking and energy-saving operation control functions. Maximize the control and precision requirements of temperature, humidity and pressure difference in the clean workshop, and provide a high-cleanliness and low-energy consumption indoor environment for the enterprise's production process.
Adjust the opening degree of the valve;
Air valve opening degree
Filter pressure difference
Supply air temperature and humidity
Supply air velocity
Return air (indoor) temperature and humidity monitoring and constant temperature and humidity control (circulating unit)
Exhaust air (indoor or supply air) temperature and humidity monitoring and independent regulation and control of constant temperature and humidity (DC system);
System air volume and pressure control
Summer/winter mode conversion control
Indoor pressure monitoring and control function
Self-diagnosis function for system hardware faults
Start-stop control of the supply fan
Automatic input function for disinfection and self-cleaning control processes (a proprietary function of the pharmaceutical factory system);
Interlock control of exhaust fan and supply fan (direct current system)
Detection of the operation and fault status of supply and exhaust fans
Differential pressure alarm for medium and low-efficiency filters
Various electrical safety protection functions such as overcurrent and short circuit;
The function of accumulating the operating time of vulnerable parts of the unit and providing maintenance prompts;
Fire signal interlock control
The interlock control function of process exhaust, process dust removal equipment and air conditioning fresh air and supply air systems (a proprietary function of the pharmaceutical factory system). Independent regulation and control of temperature and humidity in multi-unit operating rooms;
Air supply fan pressure difference protection control due to lack of air.
Product technical characteristics
1. Clean engineering mainly filters dust, bacteria and other substances in the air through the circulation of air volume, achieving control over non-biological and biological particles in the air and meeting the dust-free standard. Therefore, sufficient air volume is needed to ensure the dust-free level inside the room. The air volume of clean engineering is generally calculated based on the indoor air change rate, which is usually 10 times or even dozens of times. Especially in unidirectional flow clean rooms, the air change rate can reach hundreds of times the volume of the room.
2. Cleanroom engineering generally requires at least three levels of filters: primary, medium and high. The combined resistance of these three levels of filters is approximately 700 to 800 Pascals. Cleanroom engineering usually adopts centralized supply and return air to ensure the maintenance of positive and negative pressure regulation requirements in the cleanroom. Therefore, the pipeline resistance in the cleanroom is generally more than twice that of ordinary air conditioners. Therefore, the supply air unit of the air handling unit in a clean room generally adopts a backward-curved airfoil fan or a fan without a casing to achieve a sufficiently high supply and return air pressure head. The lower the air leakage rate of the air handling units used in clean engineering is, the more energy can be saved for customers and the lower the operating costs will be.
3. The accuracy of temperature and humidity control in a cleanroom is to meet the process requirements. For instance, in the manufacturing of certain electronic products, the control of temperature and humidity is subject to extremely strict requirements. To achieve constant temperature and humidity, it is required that the air handling unit of the clean engineering at least have functional sections such as cooling, heating, humidification and dehumidification, and a precise control method is needed. For instance, the heat exchanger should adopt high-efficiency hydrophilic fins, and the water flow rate should be controlled by proportional integral. The humidification volume should also be regulated by proportional integral or PID to achieve higher control accuracy.
4. Fully understand the purification requirements of various industries. In response to the control requirements of the industries, integrate modern purification air conditioning technology, automatic control and computer communication technology to measure, analyze and control the operating energy consumption of refrigeration and air conditioning system equipment, and provide a high-precision and low-energy consumption constant temperature and humidity environment. Flexibly adopt the optimal control strategy for different types of air conditioning systems and thermal and humidity treatment solutions; Comprehensively consider the operating environment of the system and maximize the utilization of outdoor fresh air during the transitional seasons to achieve energy-saving control of the system. It works well in coordination with air conditioning systems such as rotary dehumidification systems, fresh air pretreatment systems, and deep dehumidification systems, providing reliable and high-precision control for low-humidity environments. The controller, sensors, actuators and electrical components have all been strictly tested and verified. Imported and domestic superior brands are adopted to ensure the stability, reliability, high efficiency and energy saving of the system. It adopts an integrated design of strong and weak electricity to eliminate system interference, simplify system wiring, ensure stable system operation and facilitate operation and maintenance. The upper human-machine interface in the form of a touch screen is adopted for centralized management and simplified operation. The standard MODBUS RTU protocol is adopted, and the network communication interface supporting the mainstream international communication protocols is reserved to realize the connection with third-party systems such as the DCS system or the building system.
