Face velocity is the approach speed of air entering the core face:<\/p>\n
It is measured in metres per second (m\/s).<\/p>\n 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 a smaller core.<\/p>\n Doubling face velocity roughly quadruples the Perte de charge<\/a> across the core, which raises fan power. But a smaller core is cheaper and fits tighter casings. Selection is a balance: pick the face area that meets effectiveness at an acceptable fan penalty. This is the same lever discussed for les \u00e9changeurs \u00e0 plaques<\/a> and their pressure-drop budgets.<\/p>\n Is higher face velocity ever good?<\/strong> Only when space is tight and fan energy is cheap; otherwise lower velocity wins on lifecycle cost.<\/p>\n Does face velocity equal duct velocity?<\/strong> Not exactly – it is referenced to the core opening, which may differ from the connecting duct.<\/p>\n Need help specifying the right air-to-air heat recovery for your project? Contact the QIYU engineering team<\/a> – WhatsApp +86 157 5335 5505, or email kuns913@gmail.com.<\/p>\n Questions fr\u00e9quemment pos\u00e9es<\/strong><\/p>\n Face velocity is the volumetric airflow divided by the frontal area of the core; it is the speed of air entering the exchanger face.<\/p>\n<\/div>\n Pressure drop rises roughly with the square of face velocity, while effectiveness improves only marginally; lowering face velocity with a larger core is the usual way to cut fan energy.<\/p>\n<\/div>\nface_velocity = volumetric_flow \/ core_face_area<\/code><\/p>\nTypical range<\/h2>\n
The core-size vs pressure-drop trade-off<\/h2>\n
Frequently asked questions<\/h2>\n
What is face velocity?<\/h3>\n
Why does face velocity affect pressure drop?<\/h3>\n