A bigger, slower core recovers more heat but costs more and needs more fan power to push air through. Pressure drop is the hidden cost of every heat exchanger, and it scales roughly with the square of face velocity.
The core trade-off
- Low face velocity (under 1.5 m/s): high recovery, large core, low fan cost per unit, but bigger footprint.
- High face velocity (over 2.5 m/s): compact, but recovery drops and fan energy climbs fast.
A common sweet spot for plates is 1.5 to 2.5 m/s. Push higher only when space forces it.
Sizing for total cost
Recovery value (energy saved) versus fan cost (pressure drop times airflow times hours) should be balanced, not maximized independently. A 5 Pa saving on a 50,000 m3/h unit is worth real money over the equipment life. Tie this to the sizing guide and ROI walkthrough.
Specifying a unit for your project?
EN159 builds plate, rotary, heat-pipe and counterflow air-to-air exchangers. Send airflow (m3/h), inlet temperatures and available space and we will size it.
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