Definition Face velocity is the approach speed of air entering the core face: face_velocity = volumetric_flow / core_face_area It is measured in metres per second (m/s). Typical range For HVAC air-to-air cores, face velocity usually sits between 1.5 and 3.5 m/s. Lower is gentler on the core and the fan; higher packs more flow into […]
Heat Exchanger Pressure Drop and Fan Energy
A heat exchanger only saves energy if the recovered heat exceeds the extra electricity needed to push air through it. That trade-off is governed by pressure drop. What Drives Pressure Drop? Face velocity (higher speed = steeper rise) Core depth and plate count Surface corrugation and coating thickness Dust or fiber loading on fins Reading […]
Tunnel and Underground Ventilation Heat Recovery: Reclaiming Fan Energy
Tunnels and underground spaces move enormous volumes of air, and the ventilation fans are among the largest energy consumers on the whole facility. Jet fans push air along the tunnel, supply and exhaust fans replace it, and in a cold-climate region the incoming air is heated before it enters so it does not freeze the […]