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 […]
Fan Static Pressure Class: Matching the Fan to the Recovery Core
Static vs total pressure Total pressure is the full energy of the moving air; static pressure is the usable pushing force after velocity energy is set aside. Fans are classed by the static pressure they can develop against a system – and the recovery core is one of the biggest resistances in that system. Core […]
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 […]