FFU group-control technology is a core necessity for modern large-scale cleanrooms, especially in industries such as semiconductors, display panels, and biopharmaceuticals. It represents a leap from "single-point control" to "intelligent networked control," significantly improving the reliability, energy efficiency, and manageability of cleanroom environments.
I. What is FFU Group-Control Technology?
FFU group-control technology refers to the use of a central control system to centrally monitor, uniformly manage, and intelligently regulate hundreds or thousands of FFUs in a cleanroom. It integrates these originally independent devices into a coordinated and efficiently operating intelligent network.
II. Addressing the Pain Points of Traditional Control
1. Low Management Efficiency: It is impractical for technicians to manually adjust the fan speed of thousands of FFUs one by one.
2. High Energy Consumption: FFUs are major energy consumers in cleanrooms (accounting for 40–60 % of total power). Traditional control methods cannot adjust speed on demand, leading to full-speed operation year-round and huge energy waste.
3. Poor Stability: Voltage fluctuations can cause FFU speed variations, leading to instability in cleanroom pressure and airflow.
4. No Fault Warning: If a single FFU fails (e.g., filter blockage or motor damage), it cannot be detected in time, potentially affecting the production environment or even causing product batch loss.
5. Lack of Data Support: There is no way to record operational data, making energy analysis and optimization difficult.
III. Main Control Modes and Strategies
Group-control systems support multiple intelligent control modes that can be used flexibly or in combination according to different needs:
1. Constant Face Velocity Mode
- Principle: The system sets a target face velocity (e.g. 0.45 m/s). Each FFU automatically adjusts its motor speed based on its built-in velocity sensor feedback to maintain constant velocity.
- Advantage: Ensures uniform and stable airflow in the cleanroom.
- Disadvantage: As filter resistance increases, motor speed must continuously rise to maintain velocity, which is not energy-optimal.
2. Constant Airflow Mode
- Principle: The system sets a target airflow value. The FFU adjusts speed based on its airflow–speed–static pressure characteristic curve to maintain constant airflow.
- Advantage: Better maintains room air change rate and differential pressure.
- Disadvantage: Requires accurate FFU characteristic curve data.
3. Total Airflow Mode
- Principle: Instead of controlling individual FFUs, the system controls the total airflow of all FFUs in a zone. When filter resistance increases, the system uniformly increases the speed of all FFUs to maintain total airflow.
- Advantage: Simple control strategy.
- Disadvantage: Lower control precision; cannot ensure uniform face velocity for each FFU.
4. Differential Pressure Control Mode (Most Energy-Efficient and Advanced)
- Principle: Uses room differential pressure as the core control target. A pressure sensor installed in the room monitors the pressure difference with a reference area in real time. If the differential pressure falls below the setpoint, the system automatically increases the average speed of all FFUs in that zone to raise the pressure. If the differential pressure is too high, the system reduces the average speed.
- Advantage: Highly energy-efficient. During non-production periods or low activity, speed can be significantly reduced, offering substantial energy savings. It also directly safeguards the core safety barrier of the cleanroom-differential pressure.
IV. Key Functional Advantages of FFU Group-Control Systems
1. Centralised Monitoring and Visualisation: Real-time graphical monitoring of each FFU's status (on/off, speed, velocity, power) and alarms (filter blockage, communication failure, motor fault) on a computer.
2. Intelligent Alarming and Early Warning: The system can set alarm thresholds (e.g. final filter resistance). When FFU differential pressure is too high, an alarm is triggered to prompt filter replacement, enabling predictive maintenance and preventing environmental loss of control.
3. Energy Saving: Through differential pressure control, scheduled speed reduction (e.g. lower speed at night), and zonal control, the system can significantly reduce FFU cluster energy consumption-typically by 30–50 %.
4. Simplified Commissioning and Validation: No need for on-site individual adjustment; all FFU parameters can be set and grouped via software, greatly shortening commissioning time and generating reports suitable for GMP/FDA qualification.
5. Data Recording and Traceability: The system automatically records all operational data and alarm events and can generate custom reports to meet quality traceability and audit requirements.
V. Technology Development Trends
1. Wireless Communication: Adoption of ZigBee, LoRa and other wireless technologies to replace wired RS-485, simplifying installation-especially for retrofit projects.
2. IoT and Cloud Platforms: Connecting FFU group-control systems to industrial IoT platforms enables cloud-based monitoring, big data analytics and remote O&M.
3. AI-Based Energy Optimisation: Using AI algorithms and historical data plus production schedules to learn cleanroom environmental patterns and achieve finer, smarter energy-saving control.
VI. Conclusion
In short, FFU group-control technology upgrades cleanroom environmental control from "infrastructure" to "intelligent strategy." It is not only a means to achieve a stable environment but also a key tool for enterprises to reduce operating costs, improve management levels and realise smart manufacturing.
