HVAC engineers

AHU Filter Selection and Calculation Understanding AHU Filter Selection in HVAC Systems Filters are critical components in an AHU because they remove dust particles and help maintain indoor air quality. Proper filter selection improves system performance, protects cooling coils, and reduces maintenance costs. Common Filter Types in AHU: Pre Filter - Removes larger particles (5-10 µm ) Fine Filter - Removes medium particles (1-5 μm ) HEPA Filter - Removes very fine particles for clean environments Typical applications: Office AHU → Pre + Fine Filter Clean Room → Pre + Fine + HEPA Pharmaceutical Area → Multi-stage filtration Filter Area Calculation Formula: Required Filter Area = Airflow ÷ Face Velocity Example: Airflow = 5000 CMH Convert airflow: 5000÷3600 = 1.39 m³/s Assume filter face velocity: 2.5 m/s Filter Area: 1.39÷2.5 Required Filter Area = 0.56 m² A=QVA=\frac{Q}{V}A=VQ Where: A = Filter area (m²) Q = Airflow (m³/s) V = Face velocity (m/s) Recommended Face Velocity: Pre Filter →...