Energy saving comparison between FFU fan filter unit air supply and traditional cabinet air supply system

This is a very core and practical problem. The energy-saving comparison between FFU fan filtration unit air supply system and traditional cabinet air supply system is a key consideration in modern clean room design.
Overall, the intelligent group control FFU system using DC motors (EC motors) has far better long-term energy efficiency than traditional wind cabinet systems in the vast majority of medium to large, high cleanliness applications. The following is a detailed comparative analysis:

•  Overcoming the energy-saving advantage in system resistance (FFU wins) is the most significant and fundamental energy-saving advantage of FFU systems.
• Traditional wind cabinet system: The fan needs to provide sufficient pressure head (static pressure) to overcome the resistance of the entire system, including:
• Resistance of the air handling unit itself.
•  Friction resistance of air supply ducts that are tens or even hundreds of meters long.
•  Local resistance of countless bends, tees, reducers, and dampers on pipelines.
•  Final resistance of high-efficiency filter.
• Conclusion: A large amount of energy is wasted on overcoming pipeline friction rather than directly used for air supply.
• FFU system:
•  Almost eliminated the air supply duct. The fresh air handling unit (MAU) only needs to send the processed fresh air to the static pressure box on the ceiling, and the required pressure head is very low (usually only 250-400Pa).
• FFU comes with its own fan, which only needs to overcome the resistance of its high-efficiency filter (HEPA/ULPA) (initial resistance is about 100-150Pa, final resistance is about 250-300Pa).
• Conclusion: Energy is efficiently and directly used to push air through filters, avoiding significant losses in pipeline transportation.
•  Energy saving advantage under partial load operation (FFU wins), as the cleanroom does not operate at maximum load for most of the time.
•  Traditional wind cabinet system: Even if the production equipment is partially shut down and the filter resistance does not reach the maximum value, the central wind turbine still operates at a fixed speed. In order to regulate the air volume, it is usually done by closing the air valve, which actually increases resistance to reduce the air volume, and is an extremely wasteful throttling regulation method.
•  FFU system: adopts frequency conversion+group control strategy.
•  Affinity Laws: The power consumption of a fan is proportional to the third power of its rotational speed (power ∝ rotational speed ³).
•  When the resistance of the filter increases with use, the FFU will automatically slightly increase the speed to maintain a constant air volume, and the power consumption will slowly increase.
•  When production demand decreases (such as at night or on weekends), or when the demand for fresh air decreases, the group control system can reduce the overall speed of all FFUs. A slight decrease in rotational speed will result in a significant reduction in power consumption.
• Conclusion: The FFU system achieves extremely high operating efficiency through speed regulation at partial loads, while traditional systems have even lower efficiency at partial loads.
•  Energy saving advantages in motor efficiency and thermal load (FFU wins)
•  Motor Efficiency: The efficiency of EC motors is much higher than that of traditional AC motors, especially at partial loads, with more obvious advantages.
•  Heat load: The heat generated by EC motors is much lower than that of AC motors. The dispersed arrangement of FFU ensures that heat is evenly dispersed and easily carried away by airflow. However, the large AC motors and their driving equipment in traditional wind cabinets generate concentrated heat, which becomes a significant internal heat source in clean rooms and requires additional air conditioning cooling capacity to offset it, resulting in waste of secondary energy.

• Assuming a cleanroom of Class 10000, the required air supply volume is 500000 cubic meters per hour.
• Plan A: Traditional wind cabinet system
• The total pressure head of the system requires about 1000 Pa (of which about 700 Pa is used to overcome pipeline resistance).
• Total power of fan: 110 kW (combined efficiency of fan and motor).
• Annual electricity consumption (at 100% load, operating throughout the year): 110 kW × 24 × 365=963600 kWh of electricity
• Option B: Intelligent EC-FFU System
• MAU requires a pressure head of only 350 Pa (overcoming the air conditioning unit itself and the fresh air duct).
• Total number of FFUs: 500 units, with a single unit processing air volume of 1000m ³/h.
• FFU average operating power consumption: 0.12 kW/unit (high-efficiency EC motor, operating at optimized speed).
• FFU total power: 500 × 0.12=60kW
• MAU fan power: 15 kW
• Total system power: 60+15=75kW
• Annual electricity consumption: 75 kW × 24 × 365=657000 kWh
• Annual energy savings: 963600-657000=306600 kWh
• Energy saving rate: (306600/963600) × 100% ≈ 31.8%
• Calculated at 1 yuan per kilowatt hour, it can save about 300000 yuan in electricity bills annually. The initial investment of FFU system can be recovered within a few years through electricity cost savings.