Ventilation Filters

Reference data and engineering information about ventilation filters for hvac systems applications.

Overview

Engineering reference data for Ventilation Filters in HVAC systems.

$Q = \dot{m} c_p \Delta T$

Heat causing temperature change.

$Q = \dot{m} h_{fg} \Delta\omega$

Heat causing moisture change.

$COP = Q_c / W$

Coefficient of performance.

Ventilation filters are characterized by the following performance metrics:

Separation efficiency — ability to retain synthetic standard dust (weight and % statement)
Blacking efficiency — capability to retain atmospheric dust (optical measured and % statement)
Particle separation efficiency — capability to retain particles at fixed sizes (particle concentration measured and % statement)
Dust accumulation capacity — capability to keep standard dust before the pressure drop extends a certain value
Airflow resistance — static pressure drop of the filters

Typical dust concentrations exposed to filters in ventilation and air-conditioning systems:

Environment	Dust Concentration (mg/m³)
Rural and suburban districts	0.45 – 1.0
Metropolitan districts	1.0 – 1.8
Industrial districts	1.8 – 3.5

Made from felt, cloth, cellulose, glass, silk without adhesive liquid:

Filter Type	Air Velocity (m/s)	Resistance (N/m²)	Efficiency
Flat Panel (disposable)	0.1 – 1.0	25 – 250	20–35%
Continuous Roll (self-cleaning)	2.5	30 – 175	25%
Bag Filters	—	—	40–90%
HEPA	—	—	99.97% (≥0.3 μm)
ULPA	—	—	99.9997% (≥0.12 μm)

Panel type with viscous fluid coating, plates ~500 mm × 500 mm:

Filter Type	Air Velocity (m/s)	Resistance (N/m²)
Washable/Disposable	1.5 – 2.5	20 – 150
Continuous Roll (self-cleaning)	2.5	30 – 175

Type	Air Velocity (m/s)	Resistance (N/m²)	Efficiency
Electrostatic Precipitators	1.5 – 2.5	Negligible	30–40%
Absolute (dry panel, special coating)	2.5	250 – 625	—