Pressure Drop Is Energy

Every core resists airflow. The fan must overcome that resistance, and fan power rises with pressure. Ignored, it can erase part of the saving.

What Drives It

• Face velocity - higher velocity, much higher drop
• Channel size - narrower channels raise drop
• Core depth and configuration

Typical Values

Plate cores: 50 to 150 Pa per side; rotary wheels: 100 to 250 Pa; heat pipes: 40 to 120 Pa. These are design-point figures.

Balance

There is a sweet spot: lower velocity lifts effectiveness but needs a bigger core. Size for the point where recovered energy minus extra fan energy is maximal.