Start With the Duty
Plate exchangers are stationary, no-moving-parts cores. Selection begins with supply and exhaust airflow, indoor and outdoor design temperatures, and the allowable supply-air temperature.
Key Selection Parameters
- Face area - larger area at lower face velocity gives higher effectiveness
- Configuration - counterflow (70-75 percent) outperforms crossflow (60-65 percent)
- Material - aluminium for cost, polymer or epoxy-coated for corrosive or hygiene duty
- Separators - brazed, bonded, or welded depending on pressure and temperature
Sizing Rule of Thumb
Pick a target effectiveness (often 70 percent), then size the core so face velocity stays in the manufacturer's recommended band. Too high a velocity lowers effectiveness and raises fan power.
When Plate Is the Right Choice
- You want zero moving parts and minimal maintenance
- Air streams must stay fully separated (labs, hospitals)
- Sensible-only recovery is sufficient for your climate
Verify
Confirm the selection against an EN 308 or AHRI 1060 rating at your actual operating point, and check the added pressure drop against your fan's capability.
Before You Start
A successful Plate Heat Exchanger Selection Guide project begins with measurement. Record the supply and exhaust airflow rates, the temperatures on each side, and the hours the system runs per year. Note any contaminants in the exhaust and the available space for the core and ductwork. These figures decide both the type of exchanger and whether the payback makes sense.
Step-by-Step
First, choose the exchanger type from the air cleanliness and recovery target. Second, size the core using the measured airflow and the log-mean temperature difference, leaving margin for fouling. Third, lay out the duct path so the exhaust is filtered before the core and the supply side has drainage if it may condense. Fourth, add a bypass for free cooling and wire the fans to a simple control. Finally, commission the unit and record baseline temperatures.
Verification
After startup, compare the pre- and post-installation supply temperatures at the same outdoor condition. A steady recovery of 50 percent or more confirms correct sizing. Re-check each season and clean the exhaust side when the recovered temperature begins to fall, because fouling quietly erodes performance over time.
Frequently Asked Questions
Do I need a bypass? In most climates yes, so the system can free-cool when outdoor air is mild. How is sizing done? From measured airflow and the log-mean temperature difference, not from estimates.