This is a classic cleanroom design issue. FFU Fan Filter Units (FFU) and traditional air handling unit (AHU) systems are two main cleanroom air supply solutions. Below is a concise comparison of their advantages and disadvantages.
I. Core Concept Differences
1. FFU System:
- Distributed, modular design. Each FFU is an independent unit with its own fan and HEPA/ULPA filter, installed directly on the ceiling grid to form the cleanroom’s air supply ceiling.
2. Traditional AHU System:
- Centralized design. A large AHU processes air centrally and distributes it through an extensive ductwork network to HEPA filter boxes in the cleanroom.
II. Comparison of Advantages and Disadvantages
System Structure and Space Occupancy
- FFU System:
- Advantages: No large ductwork, saving ceiling space and reducing height requirements. Modular layout is flexible.
- Disadvantages: Ceiling is filled with FFUs, requiring reserved maintenance passages.
- Traditional AHU System**:
- Advantages: Centralized management in the machine room, fewer devices in the cleanroom.
- Disadvantages: Requires large ducts, occupying significant ceiling space and demanding higher building height.
Airflow Control and Cleanliness
- FFU System:
- Advantages: Extremely uniform airflow, stable unidirectional flow. Easily achieves local high cleanliness and adjustable indoor pressure gradients.
- Disadvantages: Uniformity depends on outlet layout and commissioning, with potential attenuation at distant outlets.
- Traditional AHU System:
- Advantages: Uniformity is easier to achieve with proper outlet layout.
- Disadvantages: Less flexible for local control, with potential uniformity issues at distant outlets.
Energy Consumption
- FFU System:
- Advantages: High fan efficiency (often using EC motors), efficient at partial load. Smart group control for energy savings.
- Disadvantages: Multiple fans, potentially large total installed motor power.
- Traditional AHU System:
- Advantages: Fewer fans (usually 1-2 large fans).
- Disadvantages: Lower fan efficiency, fixed frequency operation, high ductwork resistance, and high energy loss.
Flexibility and Scalability
- FFU System:
- Advantages: Modular design allows easy layout adjustments and expansion by adding FFUs.
- Disadvantages： Very rigid once installed, with significant effort required for changes.
- Traditional AHU System:
- Advantages: Centralized management.
- Disadvantages: Requires extensive ductwork modification for layout changes or expansion.
Maintenance and Management
- FFU System:
- Advantages**: Single FFU failure does not affect the entire system. Filter replacement can be done within the cleanroom.
- Disadvantages**: Numerous maintenance points, though manageable with remote monitoring.
- Traditional AHU System**:
- **Advantages**: Centralized equipment, convenient for maintenance.
- **Disadvantages**: Central fan failure can paralyze the system, requiring system shutdown for maintenance.
Noise and Vibration
- FFU System:
- Disadvantages: Distributed noise sources can lead to cumulative background noise.
- Traditional AHU System:
- Advantages: Main noise source is in the machine room, with lower background noise in the cleanroom after sound attenuation.
Initial Investment Cost
- FFU System:
- Disadvantages: Higher initial equipment procurement costs due to individual FFU costs.
- Traditional AHU System:
- Advantages: Lower initial equipment procurement costs.
Long-term Operating Costs
- FFU System:
- Advantages: Significant energy-saving potential, lower long-term electricity costs, and controllable maintenance costs.
- Traditional AHU System:
- Disadvantages: High energy consumption and potential for increased maintenance costs due to system complexity.
III. Summary and Selection Recommendations
FFU System
- Core Features: Flexible, efficient, energy-saving, modular.
- Typical Applications: Large-area, high-cleanliness (ISO Class 1-5) cleanrooms, dynamic production lines (e.g., semiconductor, display panels, pharmaceuticals), phased construction, and renovation projects with height constraints.
Traditional AHU System
- Core Features: Centralized, simple, low initial investment.
- Typical Applications: Small to medium-sized cleanrooms with lower cleanliness requirements (ISO Class 6-9), fixed-layout production workshops (e.g., medical devices, food packaging), tight budgets, and scenarios with high background noise requirements.
Modern Trends
The FFU system is now the mainstream choice for high-grade, large-area cleanrooms, driven by its significant energy-saving potential and unparalleled flexibility to meet the demands of modern high-tech production lines. Traditional AHU systems are increasingly limited to specific applications. When selecting a system, a lifecycle cost (LCC) analysis is essential, not just a comparison of initial investments.
Post time: Sep-13-2025