What a Membrane Plate Does
A membrane plate exchanger uses a selective membrane instead of bare metal foil between the airstreams. Water vapour passes through the membrane while the air stays fully separated. You get latent (moisture) recovery with no moving parts and no stream mixing.
Key Selection Parameters
- Membrane type - standard vapour-permeable or engineered for higher flux
- Channel geometry - counterflow reaches higher effectiveness than crossflow
- Face velocity - keep within the band that balances effectiveness and pressure drop
- Condensate management - membranes condense on the exhaust side and need safe drainage
When to Choose Membrane
- You need humidity control but cannot accept a rotary wheel
- Isolation is mandatory (hospitals, labs, cleanrooms)
- You want no motor, seals, or bearings in the airstream
Size and Verify
Size like a plate core but confirm the latent effectiveness at your humidity ratio, not just the temperature. Check the EN 308 or AHRI 1060 rating at the actual operating point and confirm the drain path.
Before You Start
A successful Membrane 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.