Within plate exchangers, airflow arrangement sets the ceiling on performance. Counterflow (streams oppose) is thermodynamically superior; crossflow (streams perpendicular) is simpler to build.
Comparison
| Counterflow | Crossflow | |
|---|---|---|
| Max sensible effectiveness | Up to ~90% | Up to ~75% |
| Coldest supply temp | Lower | Higher |
| Manufacturing | More complex | Simpler, cheaper |
| Frost | Needs careful design | Easier partial bypass |
| Best use | Max recovery, cold climate | Cost-sensitive, moderate climate |
Why counterflow
Counterflow maintains the largest average temperature difference along the plate, so it extracts more energy and reaches lower supply temperatures - valuable in cold climates.
Why crossflow
Crossflow plates are easier to sheet-metal and seal, lowering first cost for buildings that do not need peak recovery.